florida water resource journal jan 2014

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Published byBUENA VISTA PUBLISHING for

Florida Water Resources Journal, Inc.

President: Patrick Lehman, P.E. (FSAWWA)Peace River/Manasota Regional Water Supply Authority

Vice President: Howard Wegis, P.E. (FWEA)Lee County Utilities

Treasurer: Rim Bishop (FWPCOA)Seacoast Utility Authority

Secretary: Holly Hanson (At Large)ILEX Services Inc., Orlando

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Florida Water Resources Journal, USPS 069-770, ISSN 0896-1794, is published monthly by Florida Water Resources Journal, Inc., 1402 Emerald Lakes Drive, Clermont, FL 34711, on behalf of the Florida Water & Pollution Control Operator’s Association, Inc.; Florida Section, American Water Works Association; andthe Florida Water Environment Association. Members of all three associations receive the publication as a service of their association; $6 of membership duessupport the Journal. Subscriptions are otherwise available within the U.S. for $24 per year. Periodicals postage paid at Clermont, FL and additional offices.

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Volume 66 January 2014 Number 1

Florida Water Resources Journal • January 2014 3

NEWS AND FEATURES4 Here’s to 65 Years—and to You!4 Poteet Re-Elected as FWPCOA Chair

10 Technology Spotlight18 2014 FWPCOA Officers and Committee Chairs29 Taste Test to be Held at Florida Water Resources Conference47 2013 FSAWWA Awards50 2013-2014 FSAWWA Board of Governors68 Third Water Festival a Huge Success—Kevin M. Vickers

TECHNICAL ARTICLES6 Reducing Operating Costs Through Treatment Optimization: Tampa’s Advanced Wastewater Treatment

Plant Experience—Charlie Lynch, Rory Jones, Emilie Moore, Steve Tamburini, and John Toomey12 Starting Up an Underloaded Biological Nutrient Removal Process—Craig Fuller, Charles Nichols,

Mark Addison, David Wilcox, and Dwayne Kreidler30 Removing One of the “I’s” from Infiltration and Inflow—Frederick Bloetscher, Dominic F. Orlando,

and Ronnie Navarro40 Incorporation of High-Level Ultraviolet Disinfection to Meet Stringent Effluent Discharge Disinfection

Byproducts Limits—Lynn Spivey, Sean Chaparro, Steve Schaefer, and William Harrington52 Separate or Combined Sidestream Treatment: That is the Question—Rod Reardon62 Getting More Out of Activated Sludge Plants by Using a BioMag Process—Derya Dursun and

Jose Jimenez

EDUCATION AND TRAINING20 TREEO Center Training23 Florida Water Resources Conference Exhibitor Prospectus and Call for Papers49 CEU Challenge53 FWPCOA Training Calendar61 FSAWWA Training67 FWPCOA State Short School68 FSAWWA Legislative Day in Tallahassee71 PACP/MACP/LACP Training78 ISA Water/Wastewater and Automatic Controls

Symposium

COLUMNS20 FWEA Focus—Greg Chomic22 FWEA Chapter Corner—Patricia DiPiero29 FSAWWA Speaking Out—Carl R. Larrabee Jr.59 Certification Boulevard—Roy Pelletier60 Spotlight on Safety—Doug Prentiss Sr.70 C Factor—Jeff Poteet

DEPARTMENTS72 Service Directories75 Classifieds78 Display Advertiser Index

ON THE COVER: The Okeechobee UtilityAuthority Cemetery Road WastewaterTreatment Plant. (photo: JamieGamiotea)

The Florida Water Resources Journal is excited about celebrating its65th anniversary of publication this year. What began in 1949 as TheOverflow, a black-and-white, copied, and stapled newsletter sponsoredby the Florida Water & Sewage Works Operators Association, is nowthe publication you see before you: a four-color, full-service maga-zine for Florida's ever-changing water and wastewater indus-try. It serves as the official publication for the FloridaWater & Pollution Control Operators Association(FWPCOA), the Florida Section of the AmericanWater Works Association (FSAWWA), and theFlorida Water Environment Association (FWEA).

The history of water in the last sixdecades mirrors the history of thestate. Without an abundant supplyof clean, safe water, Florida would nothave had such tremendous popu-lation and economic growth. In1949, the population of the state was2.5 million people; it now stands at close to20 million—an almost ten-fold increase!Without water, Florida wouldn't have become one of the toptourist destinations in the world, with more than 60 million visitorseach year. The Kennedy Space Center, and the attendant aerospace andmilitary industries, as well as Walt Disney World and many other en-tertainment complexes, couldn't function without this vital resource.And of course, water is essential for Florida's orange industry and everyother agricultural crop.

It's interesting to note that what also started in 1949 were the of-ficial Florida welcome centers that opened on major thoroughfaresacross the state to assist auto travelers with information about attrac-tions and interesting destinations—and offer everyone a complimen-tary cup of orange juice. The Journal has been assisting water industryprofessionals for the same number of years with the information theyneed to ensure a continuous source of life-giving water, for now andthe future.

With technical and feature articles; information on education andtraining; updates from the heads of the three organizations; columnson certification, safety, legal, contractor, and other issues; the latestnews and product information; and a classified and service directory,

we strive to keep you up-to-date on every pertinent waterissue.

As the state moves forward, so does the magazine.Beginning this year, look for several exciting new

features (including a new magazine title logo):Guest Columnist –Water and wastewater-re-lated company executives, from utilities,

manufacturers, distributors, and con-sulting firms, will present theirthoughts on the issues of theday.Reader Profile –Employees willbe highlighted, discussing theirjobs and the industry.Company Profile –A full-page

article will highlight a particular com-pany's history, projects, and services.

The 65th anniversary celebration will continue as we delveinto the history of the magazine with special articles publishedthroughout the year. In August, we will dedicate an entire issue to thehistory of the Journal, as well as that of FWPCOA, FSAWWA, andFWEA.

But it wouldn't be much of a celebration without you—thereader. You are the reason the magazine exists. You are responsible forthe success of the Journal and for the achievements in the industry thathave allowed your state to grow and thrive. And that is something tocelebrate, too.

Join us in honoring this great industry by submitting an article,photographs, or historical information, or a congratulatory or histor-ical advertisement, and show support for your magazine.

–Rick Harmon, Editor

Here's to 65 Years -and to You!Here's to 65 Years -and to You!

Jeff Poteet was re-elected as president of theFlorida Water & Pollution Control Association(FWPCOA) for 2014 by the organization’s boardof officers at their November 2013 meeting. Heserved as the organization’s president in 2013.

Poteet is general manager of the water andsewer department for the City of Marco Island. Hebegan his career as a wastewater operator trainee in1992, advancing to his current position in 2010.He is in charge of three drinking water facilities,two wastewater facilities, an aquifer storage and re-covery system, a reuse distribution system, and thecollection and distribution system for two separate drinking waterand wastewater service areas.

Poteet has served FWPCOA at both the regional and state level.At the regional level, Jeff has been active in setting up schools and

workshops since the late 1990s, and has held the postsof secretary/treasurer, vice chair, and chair. From 2003to 2008, Jeff served on the state board of directors asthe local region’s representative, in 2009 and 2010 assecretary/treasurer-elect, and in 2011 and 2012 as vicepresident.

“I’m excited about serving as the FWPCOApresident for another year, along with the rest of theslate of officers, who were also re-elected. I look for-ward to continuing to focus on opportunities to growour membership, find ways to get our members moreinvolved in the industry, and expand our training

programs. I am truly honored to have been given this opportunityfor a second term and I look forward to working with our sister as-sociations and other water-related organizations in the comingyear.” ��

Poteet Re-Elected as FWPCOA President

4 January 2014 • Florida Water Resources Journal


The City of Tampa (City) owns and oper-ates the Howard F. Curren AdvancedWastewater Treatment Plant (Plant). The

original facility was constructed in the 1950sand provided primary treatment of the City’swastewater prior to discharge to Tampa Bay.Various upgrade and expansion programs im-plemented by the City over the years have in-creased the capacity of the plant, providedhigher levels of treatment, increased energy ef-ficiency and enhanced cogeneration, improvedresiduals handling, and met other objectives.Currently, a combination of physical, chemical,and biological unit operations and processes areused to provide a high level of treatment.Treated effluent from the plant is discharged toTampa Bay, used within the plant for processpurposes and for irrigation, or provided to theCity’s reclaimed water customers through a dis-tribution network. The residuals handling sys-

tem at the plant receives sludge from the pri-mary settling facilities and the excess solids fromthe biological treatment stages. The system in-cludes volume reduction, stabilization, dewa-tering, and drying operations. Treated residualsfrom the heat drying system are hauled to a fer-tilizer company for further treatment andblending. Dewatered solids that have not beenthrough the heat drying process are disposed ofby land application.

The Plant has a permitted treatment ca-pacity of 96 mil gal per day (mgd) on an aver-age annual daily flow (AADF) basis. The 2011AADF for the Plant equaled 57.5 mgd. Cur-rently, the permit for the plant issued by theFlorida Department of Environmental Protec-tion (FDEP) requires high levels of carbona-ceous biochemical oxygen demand (CBOD5),total suspended solids (TSS) and nitrogen re-moval, as well as dechlorination and post aera-

tion. Furthermore, the FDEP permit sets limitsfor recoverable nickel and a trihalomethanecompound (dichlorobromomethane) and es-tablishes requirements related to effluent toxic-ity. The major treatment processes of the Plantare shown in Figure 1 and include:� High-Purity Oxygen (HPO) Carbonaceous

Reactors� Diffused Aeration Nitrification Reactors

(DARs) � Denitrification Filters

Reducing Operating Costs Through Treatment Optimization: Tampa’s Advanced

Wastewater Treatment Plant ExperienceCharlie Lynch, Rory Jones, Emilie Moore, Steve Tamburini, and John Toomey

Charlie Lynch is wastewater departmentchief engineer and Rory Jones is wastewaterengineer at City of Tampa. Emilie Moore isproject manager, Steve Tamburini is processengineer, and John Toomey is seniorengineer at Tetra Tech in Tampa.

F W R J

Figure 1. Howard F. Curren Advanced Wastewater Treatment Plant Process Schematic


Many of the treatment technologies em-ployed at the Plant are modern; however, ad-vances in biological nitrogen removalprocesses offer potential savings in operatingcosts. Also, other process enhancements andsupplementary technologies could offer eco-nomic benefits. Since the current flows andloadings are well below design values, it maybe possible to modify the treatment process toachieve nitrogen removal and increased effi-ciencies without building additional struc-tures. Like many public entities, the City isfacing significant financial constraints; there-fore, potential optimization programs involv-ing relatively small capital expenditures andthe savings in operation costs must result inshort payback periods. The operating budgetfor the Plant includes substantial costs forpower and the purchase of methanol for thedenitrification process. Due to the magnitudeof these costs and increasing fiscal pressures,the City authorized Tetra Tech to develop andevaluate specific alternatives that could lead toreductions in operating expenditures. Thiswork was conducted as part of the process op-timization feasibility study.

Process Optimization Feasibility Study

An initial assessment of the Plant identi-fied four general areas where the plant opera-tion could be optimized, resulting in potentialenergy savings and chemical reduction, andthus, reduced costs, including:� Alternative 1 - Enhancing anaerobic diges-

tion by increasing primary solids recovery.� Alternative 2 - Reducing the nitrification

requirements in the secondary basin bysidestream treatment of recycled ammoniathrough the SHARON® process (Alterna-tive 2A) or CAST process (Alternative 2B).

� Alternative 3 - Carrying out suspendedgrowth denitrification in the existing aera-tion basin to reduce methanol require-ments in the denitrification filters.

� Alternative 4 - Evaluating alternatives foroptimizing the HPO system.

Alternative 1 explored enhanced primaryclarification to increase the solids settling inthe clarifiers with a chemical coagulant andsending more solids to digestion. Optionsevaluated included the addition of iron or alu-minum salts upstream of primary settling toincrease primary treatment efficiency and co-generation as a result of increased anaerobicdigester loadings. A bench-scale study usingferric chloride was developed by Tetra Techand conducted by the City's laboratory andoperations staff.

Alternative 2 evaluated use of two tech-nologies for sidestream processes to treat recy-cled ammonia-nitrogen and thereby reduce theoxygen demand in the main aeration basin.One was the SHARON® process (Alternative2A), a biological process developed in Europe,and the other was the R-CAST® system (Alter-native 2B), a physical/chemical process with re-covery of ammonia for use as a fertilizer.

Alternative 3 evaluated denitrification inthe existing diffused aeration reactors (DARs)by setting up anoxic zones, thereby reducingoxygen demand in the DARs and chemicalmethanol needs in the denitrification filters.This is accomplished by creating anoxic zoneswithin the activated sludge treatment processwhere nitrate can be reduced to nitrogen gasby facultative bacteria. This process modifica-tion would be implemented within existingbasins and result in lower power consumptionand decreased chemical consumption in thesubsequent stages of treatment.

Alternative 4 evaluated turning down orreplacing the HPO system. The Plant has acryogenic HPO generation process, with ca-pacity to meet the oxygen demand for the fullplant capacity. Since the current oxygen de-mand is less than the design capacity, excessHPO is being generated. This alternative eval-uated turning off the HPO system and usingmechanical aeration within the various reac-tors to provide the oxygen needed for CBOD5

removal in the initial stage of treatment. The costs associated with the different al-

ternatives were developed utilizing the 2008electrical and methanol costs. Additionally, thepayback period for the proposed alternativeswas calculated, as shown in Table 1.

Alternative 3 appears marginal from aneconomic standpoint at current price levels forpower and methanol; however, the analysis in-

cluded costs for a new floor-cover-diffusedaeration system and the installation of an au-tomated aeration control system. The replace-ment of the aeration system should beconsidered normal renewal and replacementand an automated aeration system would be atypical feature for such a large plant. If thesetwo costs are removed from the analysis, sus-pended growth denitrification is very cost-ef-fective, resulting in a payback period of lessthan two years. Savings associated with thisoption are anticipated to be approximately$400,000 per year.

For Alternative 4, the existing HPO gen-eration system is producing significantly moreoxygen than needed to provide removal ofCBOD5. This situation results from a limitedturndown capability and there does not ap-pear to be a simple and effective means ofmodifying the HPO generators to correct thesituation. If the HPO generation systems wereto be shut down, the mechanical aeratorswithin the HPO train can be used to provideaeration in a conventional manner; however,the tank headspaces will need to be vented.

Based on these findings, it was recom-mended that the City further evaluate the via-bility of Alternatives 3 and 4.

Tampa Takes the Next Step

The evaluation of Alternatives 3 and 4 in-clude the development of a wastewater processmodel using GPS-X process simulation soft-ware. For Alternative 3, the model is used tohelp identify potential on/off aeration schemesin the DARs in an effort to achieve denitrifi-cation upstream of the denitrification filters todecrease methanol use. For Alternative 4, themodel is used to check the viability of con-

Table 1. Economic Sensitivity Based on 2008 Prices

Continued on page 8


verting the HPO reactors to air-activatedsludge reactors in an effort to decrease aera-tion cost and allow for denitrification in theDARs.

Alternative 3 ModelingFor Alternative 3, a calibrated GPS-X

model was prepared to demonstrate howon/off aeration could be implemented in theDARs to maximize denitrification, as shownin Figure 2. The amount and rate of denitrifi-cation is highly dependent on the amount ofCBOD available. A bypass around the HPOreactors can supply up to 30 percent of the pri-mary effluent flow directly to the DARs to in-crease the CBOD available for denitrification.

Despite operating the HPO reactors with a lowsolids retention time (SRT) of less than oneday, limited nitrification is achieved in theHPO reactors (typically effluent nitrate con-centrations between 6 to 12 mg/L) due towaste activated sludge (WAS) being recycledfrom the DARs to the HPO reactors. TheHPO bypass and limited nitrification in theHPO reactors allow for high-rate denitrifica-tion to occur if anoxic conditions are intro-duced at the beginning of the DARs.

Several variables were modeled to opti-mize denitrification, including the percent ofprimary effluent that bypasses the HPO reac-tors, static anoxic zones, and variable timingof on/off aeration. It was found that the opti-mal bypass flow was 30 percent of the influent

flow rate. Bypass above this percentage re-sulted in increased effluent ammonia concen-trations when operating at a constant SRT. Theincreased bypass flow changes the bacterialpopulation distribution between facultativeand autotrophic nitrifying bacteria. It wasfound that as more facultative bacteria aregrown in the DARs, less nitrifying bacteria arepresent, unless the mixed liquor concentrationis increased, which would result in overload-ing the clarifiers.

With a 30 percent bypass flow, it wasfound that the optimal denitrification per-formance was obtained using an on/off aera-tion scheme compared to the use of staticanoxic zones. Each DAR is divided into sixcells that can be operated as different aerationzones. The optimal denitrification perform-ance was found to occur when the first zonewas dedicated as anoxic, while Zones 2-5 wereoperated in an on/off aeration scheme. Zone6 was continuously aerated to maintain aero-bic conditions entering the clarifiers. Theon/off timing was modeled using equal on/offcycles of four hours at current loadings. Thedenitrification performance was found to be25 percent better using this approach, com-pared to using two static anoxic zones. Themodeling showed that the readily biodegrad-able influent CBOD was completely consumedby the end of Zone 1, indicating that high-ratedenitrification did not occur beyond Zone 1.Denitrification occurred during the off cyclesusing solubilization of particulate and col-loidal CBOD, and endogenous respiration asthe carbon sources. Using two static anoxiczones did not provide as much time for en-dogenous respiration to occur, resulting in lessdenitrification, which is why it did not per-form as well as on/off aeration.

At the current plant loading, the model-ing showed that between 6 and 10 mg/L of ni-trate could be denitrified in the DAR withouteffecting nitrification efficiency. Figure 3shows the denitrification performance undermaximum nitrogen concentrations at currentflows. By denitrifying in the DARs, lessmethanol is required in the denitrification fil-ters. The Plant currently doses 2.9 mg ofmethanol for every mg of nitrate denitrified inthe filters. This dose is close to the theoreticalminimum of 2.86 mg of methanol per mg ni-trate, indicating there is little room for opti-mizing the methanol dose rate. Denitrifying10 mg/L of nitrate in the DAR will save ap-proximately $1.1 million annually, based oncurrent methanol pricing of $1.50 per gal. Asflows increase at the Plant, additional aerationtime will be required to complete nitrification,which will decrease the off-cycle times, result-ing in a decrease in savings. In addition to the

Figure 2. Alternative 3Model Configuration

Figure 3. Denitrification Performance for Alternative 3 Using On/Off Aeration

Continued from page 7


methanol savings, aeration savings would berealized with anoxic oxidation of CBOD in thedenitrification process, which is estimated at$81,000 per year.

Alternative 4 ModelingFor Alternative 4, the HPO reactors in the

GPS-X model were converted to conventionalair activated sludge (CAS) reactors, as shownin Figure 4. The modeling showed that for thisalternative, the availability of CBOD in theDARs was still the limiting factor for optimiz-ing denitrification. The model was run at con-ditions that allowed for limited CBODremoval in the CAS reactors by operating at alow 0.5-day SRT and a low DO concentrationof 0.2 mg/L, which resulted in relatively highconcentrations of CBOD in the DARs. It wasfound that operating the DARs using aLudzack-Ettinger (LE) process (static anoxiczone at the head of the DARs without mixedliquor recycle) resulted in denitrification of 12to 16 mg/L of nitrate in the DARs, while usingan on/off aeration control resulted in onlydenitrifying 8 to 12 mg/L of nitrate. The DARSRT was maintained at 15 days for both modelruns, which resulted in the same effluent am-monia concentration of approximately 0.5mg/L. Figure 5 shows the denitrification per-formance for Alternative 4 under maximumnitrogen concentrations at current flows.

The estimated methanol savings for Al-ternative 4 using current methanol prices of$1.50 per gal increases to approximately $1.65million a year due to additional denitrificationin the DARs. In addition to methanol savings,Alternative 4 will realize significant aerationsavings. The net reduction in power con-sumption anticipated with this alternative isapproximately 3,680,000 kWh/year, whichwould decrease greenhouse gas emissions byover 2,900 tons/year. Cost savings under thisscenario are expected to equal approximately$250,000 a year and the capital investmentwould be relatively small.

On/off aeration had better denitrificationperformance for Alternative 3, but it did nothave better performance for Alternative 4. ForAlternative 4, there was adequate CBOD avail-able for denitrification throughout both anoxiczones in the LE process. While overall denitrifi-cation performance was better, there are severalconcerns using this approach. Denitrificationwithin the DAR clarifiers might be a problem,considering there will be relatively high con-centrations of nitrate going to the clarifiers,with an increased oxygen uptake rate due tomore CBOD removal in the DARs. While themodel predicted good overall performance withthe highest denitrification for Alternative 4, op-erating the HPO as CAS reactors with low SRT

and low DO could result in poor settleability.Predictions of changes in settleability cannot beaccurately modeled; therefore, a pilot demon-stration should be performed to demonstratethat good settleability can be maintained inboth the CAS and DARs.

Tampa Plans for Implementation

Treatment plants are designed to operateat a design capacity that is typically higherthan current flow and loading conditions.While plants are underloaded, there is usuallyample opportunity to optimize the processand operate with a different mindset when atcapacity. The Plant is currently loaded atabout 60 percent of design capacity. The Cityhas taken a systematic approach of perform-ing studies and evaluating alternatives, and hasbegun to implement the best optimizationstrategies by integrating the necessary im-

provements within planned capital replace-ment projects.

The aeration diffusers in the DARs needto be replaced. The design of the aeration dif-fusers in the DARs will incorporate the abilityto operate in on/off aeration mode as describedin Alternative 3. This will allow the City to takeadvantage of some methanol savings throughdenitrification in the DARs while the HPO sys-tem is in operation. The City is still evaluatingthe possibility of temporarily converting theHPO reactors to CAS reactors while the plant isunderloaded to maximize denitrification up-stream of the denitrification filters as describedin Alternative 4. The new aeration system in theDARs will be designed to incorporate such aconversion if it is made in the future. Imple-menting either alternative will result in signif-icant operational savings that can be used tofund future optimization and capital improve-ment projects in the future. ��

Figure 4. Alternative 4 Model Configuration

Figure 5. Denitrification Performance for Alternative 4


The PAT 949 CombinationTruck, at first glance, looks like a vac-uum truck; however, that is only partof the story (and its capabilities).

The PAT 949 CombinationTruck can vacuum, but the PolstonProcess™ also combines down-hole pumping capabilities. Thetruck overcomes the limitations ofvacuum technology, but the “restof the story” is that it is capable ofremoving material from very wetand/or deep conditions.

The proprietary technology,including both the equipment andprocess, was developed to reachand remove debris (sand) thatheretofore has not been removedbecause of the physical (gravity)limitations of vacuum technology.

Having an understanding ofthe natural limitations of vacuumtechnology is critical to under-standing this product’s role in themaintenance of wastewater collec-tion and treatment systems whilein operation. The equipment hasbeen designed to vacuum, as wellas reach and remove, material thatvacuum technology cannot, chal-lenging the limits of the currentmaintenance paradigm.

There are two naturally oc-curring limitations to all vacuumtechnology: depth and water.

Depth – As for the limita-tions associated with debris beinglocated at a very deep level, con-sider that a perfect vacuum canonly “suck” clean water about 30ft vertically. Why does this matter?Because many pipes and otherstructures are either buried verydeeply or have high walls to over-come. When you consider theheight of the debris box/tankabove the ground and add debris(sand) to the water, which in-creases the density, the effectiveheight (or suction reach) is short-ened significantly. This reduces

the effectiveness of vacuum capa-bilities. (Source: http://answers.yahoo.com/question/index?qid=20080220174717AAktnxG )

Water – As for the limitationsassociated with too much water,consider that a vacuum removesair; therefore, it accumulateswater and debris in the debrisbox/tank. In wet conditions (e.g.,structures with a lot of water), thedebris box/tank will fill up withwater sooner than with debris.When this occurs, the operationmust cease so that the debrisbox/tank can be emptied. Oncethe debris box/tank is full of wateror debris, it must be emptied.

To further illustrate: givenvery wet conditions (lots of waterpresent), two problems emerge forvacuum technology and both in-crease cost. First, the water keepsfilling up the debris box/tank so re-moving the debris (sand) takesmuch longer. This limits the rate ofdebris removal, and the longer ittakes, the more it costs. Secondly,the removed debris material mustgo to a landfill, which is always re-quired for wastewater systems. But,landfills only take “paint filter dry”debris, which is material with no“free” water. Costs increase whenmaterial is handled multiple timesto remove excess water.

The company’s process re-moves water; therefore, it accumu-

lates only debris (sand) in the de-bris box/tank. In wet conditions,the PAT 949 Combination Truckdebris box/tank fills up with debrisbecause the process continuouslyseparates, under pressure, thewater from the sand until the de-bris box is filled with the “paint fil-ter dry” material, which can thenbe immediately disposed of, withno additional handling.

In 2012, Polston AppliedTechnologies introduced anddemonstrated its new truckthroughout Florida. It features thesame vacuum capabilities familiarto the water and wastewater utilityindustry, as well as combining adown-hole system that adds ex-panded capabilities to the main-tenance tool bag.

In order to spotlight thetruck, the gravitational (or natu-ral) limitations of vacuum tech-nology are an important startingpoint in order to understand howit expands the maintenance capa-bilities available to the industry.The truck handles dry, damp, wet,and submerged debris from depthsto 150 ft below the surface.

The truck was designed toremove debris, such as sand; ragmaterial; and fats, oils, and grease(FOG), from structures in thewastewater collection and treat-ment systems while they remainin operation.

What is a Combination Truck?

The truck combines bothvacuum and down-hole capabili-ties. The vacuum system isequipped with a 3650-cfm blowerand the down-hole system beginswith a 2500-gpm minimum capa-bility. One of the most uniquefeatures of the truck is that bothcapabilities can be interchangedinstantly with a flip of a switch.

Both the vacuum and down-hole systems are mounted on thesame Peterbilt 367 Chasis. Thetruck is equipped with a minimumof 800 ft of jetter hose, with swiveland tilting action for large-diame-ter pipe cleaning. Finally, the 49-ftknuckleboom crane, which is cou-pled with a proprietary dripless,telescoping (vacuum and pressure)tube system, provides the dexterityand reach required to remove de-bris from collection and treatmentsystem structures.

The truck’s patented processremoves debris and “paint filterdry” material from wet or sub-merged conditions. For dry ordamp material, the truck assignsits vacuum technology the task.However, if there are significantamounts of water present, thenthe work must stop frequently be-cause the vacuum collects thewater that must be decanted, lim-iting the run time and the amountof sand removed in each load.

For wet and submerged condi-tions, the truck calls on its propri-etary down-hole technology capableof removing sand until loads of“paint filter dry” material are gener-ated and ready to be taken directlyto the landfill for final disposal.

The PAT 949 CombinationTruck “flips the switch” and tran-sitions to meet the demands ofany conditions encountered. ��

Poston Applied Technologies PAT 949 Combination Truck

T E C H N O L O G Y S P O T L I G H T

Technology Spotlight is a paid feature sponsored by the advertisement on the facing page. The Journal and its publisher do not endorse any product that appears in this column. If you would like to have your technology featured, contact Mike Delaney at 352-241-6006 or at [email protected].


In wastewater treatment facilities, someunit processes can be designed to be ex-tremely flexible for varying flow rates and

loads of wastewater. Examples of unitprocesses that will sometimes operate better atlower than designed loading rates include me-chanical bar screens, tertiary filters, pump sta-tions, and clarifiers. Processes that are difficultto operate in an underloaded state are biolog-ical treatment processes, including aerationbasins; biological nutrient removal (BNR) sys-tems; oxidation ditches; anoxic basins; andanaerobic basins for biological phosphorousremoval. This difficulty is compounded whenstarting up new or altered facilities, especiallywhen the Facility has permitted nutrient dis-charge limits. This article presents an exampleof an extremely underloaded startup (less than50 percent of capacity and less than 30 percenttotal nutrient capacity) and some key metricsand potential pitfalls to consider when start-ing up or operating such a facility.

Facility Expansion

Pre-Expansion FacilityPolk County’s Northeast Regional Waste-

water Treatment Facility (Facility) was an ex-isting wastewater treatment facility rated for anaverage annual treatment capacity of 3 mil gal

per day (mgd), with a maximum month influ-ent five-day carbonaceous biochemical oxygendemand (CBOD5) of 246 mg/l and Total Kjel-dahl Nitrogen (TKN) concentration of 40mg/l. The Facility is located near the intersec-tion of Interstate 4 and U.S. 27, in close prox-imity to theme parks and near the border toOsceola County, Lake County, and OrangeCounty. The Facility typically discharges a por-tion of its effluent to rapid infiltration basins(RIBs) for aquifer recharge. The RIBs have a re-ceiving permitted limit of 12 mg/l of nitrogenas nitrate to prevent a buildup in the soil.

The existing biological treatment unitprocess consisted of two Carrousel-type oxi-dation ditches, each rated for 1.5 mgd. Eachoxidation ditch has a volume of 0.75 mil gal(MG) for a hydraulic retention time (HRT) of12 hours. With a designed operating mixedliquor suspended solids (MLSS) concentrationof 3,500 mg/l, a solids retention time (SRT) of8.8 days is achieved. The ditches did not haveanoxic zones and were capacity-limited whenapproaching their aeration limits due to theirlimited ability to remove nitrates through bi-ological denitrification.

The upstream and downstream unitprocesses will not be discussed significantlydue to their ability to handle fluctuating flowmore easily. Downstream processes are af-

fected by the ability of the biological processesto perform correctly. When anoxic conditionsare not achieved prior to entering the clarifiers,it is common for denitrification to occur in theclarifiers, leading to a condition known assludge “pop-ups.”

Expanded Facility DesignWhen the Facility expansion design

began, the area was experiencing significantgrowth, with new development being permit-ted and constructed within the service area.When the original design began in 2006, it wasexpected that the Facility would be receivingmore than 3 mgd by the start of 2010. To ac-commodate the expected growth, the Facilitywas originally thought to require 9 to 12 mgdof treatment capacity. Although growth slowed,it was expected that the Facility still had an im-mediate need of 6 mgd of treatment capacity,with the capability to upgrade to 9 mgd in thefuture. To compound the hydraulic capacity re-quirements, influent sampling during the pre-liminary design indicated the maximummonth CBOD5 strength of the wastewater hadincreased from 246 mg/l to approximately 600mg/l and the influent TKN had increased from40 mg/l to approximately 65 mg/l. The increasein loading meant that the future Facility wouldneed to provide significantly more oxygen perunit volume of wastewater on an actual oxygenrequirement (AOR) basis than the original de-sign contemplated. The oxygen demand for theexpanded Facility was estimated to be 52,736lb/day (AOR) based on the design flow rate of6 mgd versus 12,384 lb/day for the original 3-mgd design.

To augment the existing oxidationditches, a BNR process was proposed with ex-

Starting Up an Underloaded Biological Nutrient Removal Process

Craig Fuller, Charles Nichols, Mark Addison, David Wilcox, and Dwayne Kreidler

Craig Fuller, P.E., is a senior water andwastewater engineer at URS Corporation inBartow. Charles Nichols is a regionalwastewater treatment plant manager andMark Addison, P.E., is the capital investmentprogram manager with Polk County Utilities.David Wilcox, P.E., is the water/wastewatergroup manager at URS Corporation inTampa. Dwayne Kreidler, P.E., is a seniorengineer at ARCADIS in Orlando.

F W R J

Figure 1. Schematic Layout of Biological Nutrient Removal: One Operational Mode

tensive flexibility. The process has a minimumtreatment volume of 2 MG, with a “floating”equalization volume of 1.5 MG, for a total vol-ume of 3.5 MG. The design MLSS for the Fa-cility was increased to 4,000 mg/l to decreasethe volume required so that an SRT similar tothe original design could be maintained. Thisalso maintained similar hydraulic retentiontine (HRT) metrics with the existing plant.

The BNR is split into four equal-sizetanks, with each tank having three aerationzones in the center and two nonaerated zones,one at each end. The air can be distributedthrough any, all, or none of 12 total aerationzones, each with a capacity of approximately1,400 standard cubic feet per minute (scfm)per zone using fine bubble aeration. The eightzones that do not have aeration are located ateach end of each tank. At the western end ofeach tank, recycling propeller pumps allow forthe return of up to 6 mgd per propeller pumpto the eastern end of the tank.

One of the intended operational modes ofthe biological treatment (as depicted in Figure1) has the raw wastewater and return activatedsludge (RAS) enter the BNR at the east end ofTank 1 going west. The mixed liquor pathchanges direction and travels north to Tank 2,then heads east. At the eastern end of Tank 2,the mixed liquor enters Tank 3, changes direc-tion, and heads West in Tank 3. Finally, themixed liquor enters Tank 4, heads east, andexits the process at the east end. The flow caneither go to the existing oxidation ditches forpolishing treatment, with the oxidation ditchesoperating either in parallel or in a series, or by-pass them and go to the clarifiers for clarifica-tion. With key recycle pumps in the BNR, thenitrates created by nitrifying bacteria can be re-turned to anoxic zones for nutrient removal.

In the mode of operation discussed, thebiological treatment system was envisioned tobe operated with the influent BNR tank, Tank1, having an anoxic zone at the front, followedby an aerobic zone. The recycle pump in Tank1 was intended to be on to allow for nitrogenrecycle and nutrient removal. The western endof Tank 2 was intended to generally be an aer-obic zone, followed by anoxic at the east end asthe mixed liquor enters Tank 3. The easternend of Tank 3 was intended to be anoxic, fol-lowed by aerobic at the western end, with therecycle pump in Tank 3 being on for nitrogenrecycle. Finally, the western end of Tank 4 wasintended to be aerobic, followed by the east-ern end being anoxic. Following the anoxicarea in Tank 4, the mixed liquor flow would ei-ther go to clarification or enter an aerobic zonein Oxidation Ditch #1, followed by an anoxiczone. The mixed liquor in Oxidation Ditch #1would then travel to Oxidation Ditch #2 for a

final aerobic zone, followed by an anoxic zone.Denitrification is accomplished by recycling

nitrified mixed liquor from Zone 5 in Tanks 1and 3 to Zone 1 in Tanks 1 and 3, respectively,which operate in an anoxic mode. Tank 4 has ananoxic zone present near the outlet to allow fordenitrification that had not previously occurred,increasing the ability of the clarification if the ox-idation ditches are bypassed. The amount of op-erational flexibility built into the BNR processrequires a determination of how large the anoxiczones and aerobic zones will be, the selected ox-idation reduction potential (ORP) for process

control, and a selection of the amount of nitro-gen recycle flow desired. The process calculationswill be discussed.

Facility Influent After ExpansionThe housing market had a sudden down-

turn during the design, and the slump contin-ued throughout the construction of the Facility.The result was that the influent flow was onlyabout 2.5 mgd when the expanded Facility wasready to be placed in operation. With all pack-age plants in the same area diverted to the Fa-

Continued on page 14



cility, maximum month influent flows of ap-proximately 3 mgd were recorded. In addition,the strength of the influent wastewater wasmore in line with what was seen prior to thepeaking events, or in the range of 300 mg/lCBOD5. The influent nitrogen was still high atabout 50-60 mg/l TKN, but not near the levelsroutinely seen during the design period.

With all four BNR tanks and both oxida-tion ditches in operation, the HRT was deter-mined to be approximately 28 hours and theSRT, excluding equalization, would be 22.3 daysbased on a MLSS of 4,000 mg/l as designed. Thenew RAS pumping system was capable of beingtuned to 3 mgd at a concentration of approxi-mately 8,000 mg/l, and was not an operationalproblem for the process.

While this extensive aeration capabilityand long SRT leads to relatively easy treatmentof CBOD5 and quick nitrification of ammo-nia, it can be tricky to operate the Facilityunder these conditions and still meet effluentnutrient limits. Upon initial startup of the fa-cility, some of the parameters were adjusted toallow for the Facility to operate better, such aslowering the MLSS to about 2,000 mg/l, re-sulting in an SRT of approximately 11 days.Operations staff was still recording a steady in-crease in effluent nitrate levels; in some in-stances, nitrate levels exceeded influentnitrogen levels. It was also noted that the ef-fluent quality of wastewater leaving the BNRwas sometimes better than the effluent qual-ity of the wastewater leaving the oxidationditches. It is speculated that nitrogen fixationand ammonification was occurring, where ni-trogen in the air was being converted to am-monia (Leschine, et al., 1988) then nitrified tonitrates due to the presence of anaerobic con-ditions, followed by very aerobic conditions.Although evidence indicated nitrogen fixation,more data would be necessary to prove it wasoccurring. Ammonification of TKN and nitri-fication was evident due to the increase in ni-trates through the process.

Operational Calculations

Process RecalculationsOperations staff was experiencing diffi-

culties meeting effluent nitrate requirements.Process calculations were revisited utilizing in-fluent flow rates of 2.5-3.5 mgd with bio-chemical oxygen demand (BOD) and TKNconcentrations of 275-300 mg/l and 50-60mg/l, respectively. The sizing of ideal treat-ment unit processes was considered based onboth current and projected flow rates andloadings. It was expected that the nutrientloading would be much higher than what was

actually measured, and influent flow would beclose to 3.5-4.5 mgd with the diversion of flowfrom existing package treatment plants in theservice area.

Recalculation of the ideal unit process pa-rameters was performed in order to allow theprocesses to work at their peak. While the BNRhas the capability of aeration and anoxic,among other treatment capabilities, if the zonesare not sized effectively, the treatment processescan get out of control, leading to large swingsin both oxygen demand and effluent waterquality from the biological unit process.

Food to Mass Ratio and Solids Retention TimeThe first items to consider are the food to

mass (F/M) ratio and the SRT. The BNR was in-stalled with fine bubble aeration and should,therefore, not be left without water in the basin.To lower the SRT to approximately eight days,as intended, both oxidation ditches would haveto be removed from the treatment process andthe MLSS would have to be lowered. It was cal-culated that if the MLSS was set to approxi-mately 2,500 mg/l, the SRT would be 7.9 days,excluding equalization volume. This would alsoachieve an F/M ratio of approximately 0.18-0.2,which is ideal for the treatment process. If theprocess were to be started up with all bays func-tioning and the MLSS at 4,000 mg/l, the F/Mratio would be only 0.07, or far below the levelsneeded to sustain the process. The following areexamples of the equations used to size the SRTand F/M ratios (Metcalf & Eddy, et al., 2003):

It is more common to calculate the SRTwith the rate of wasted sludge, but the calcula-tions can be compared to each other to verifyactual yield of MLSS from BOD and to con-firm the calculations based on wasting rate arecorrect.

Anoxic Zone RequirementsThe primary anoxic zone was the next

item to be considered. The specific denitrifica-tion rate (SDNR) was calculated based on thetypical minimum temperature of the waste-water. The size of the anoxic zone required isbased on the nitrogen to be denitrified, theSDNR, and the volatile portion of the MLSS,or mixed liquor volatile suspended solids(MLVSS). Because of the need for CBOD5 inthe denitrification process, it is critical that theanoxic zone be located at the front of the bio-logical process to allow it to be most effective.Based on the revised influent characteristics,

and a flow rate of 3 mgd, the minimum size ofthe anoxic zone was determined to be 0.477MG and the ideal size was determined to be ap-proximately 0.729 MG, which allows for con-version of some of the organic nitrogen toammonia/ammonium. The following are ex-amples of the equations used to size the anoxiczone (Metcalf & Eddy, et al., 2003).

The volume equation for the anoxic siz-ing allows removal of the influent TKN as am-monia, and while increasing that value, allowsconversion of organic nitrogen as BOD to am-monia/ammonium, which can occur if slightlyanaerobic conditions exist at the end of theanoxic zone. The first volume calculation ofthe size of the anoxic volume has no safety fac-tor and is typically the minimum volume to beeffective only for denitrification. The nitrogenremoval equation is somewhat conservative;the low wastewater temperature is actuallyabout 26°C and not all TKN can be removedthrough denitrification. These values arehigher than the “rule of thumb” volumes forhydraulic retention times of 2-4 hours due tohigher than typical influent TKN values.

Recycle RateThe nitrogen recycle rate is typically de-

termined by the target effluent nitrogen. Thereis typically no penalty for over-recycling to theanoxic zone, except that CBOD5 will be uti-lized early in the treatment process. Using toomuch CBOD5 early for aeration can lead to theneed to add a carbon source later in theprocess, adding to the expense of the opera-tion. With a properly-sized anoxic zone, and arecycle rate of five times influent (3 mgd in-fluent in this case), the nitrate effluent was cal-culated to be 6 mg/l. Therefore, the recycle ratewas set at this rate to allow for maximum re-duction of nitrate in the effluent. The follow-ing equation is used to calculate the requiredrecycle rate for removal of nitrates (Metcalf &Eddy, et al., 2003).

Oxygen RequirementsThe AOR, without a safety factor, was cal-

culated to check if the process was providingContinued on page 16



theoretical sufficient oxygen for the influentBOD and TKN. The following is a calculation

of the AOR in lbs for the existing system:Note that a credit was given for anoxic use

of nitrates, which is typically on the order of2.86 lbs of oxygen per lb of nitrate reduced(Metcalf & Eddy, et al., 2003). There was not asafety factor of 1.1 for the kS due to the use ofreal experimental efficiency in the aeration cal-culations in later calculations (Ott submittal,2009). Finally, the aeration volume was calcu-lated to see if the process had sufficient vol-ume to achieve full BOD oxidation andnitrification. The following calculations showthe minimum aerobic volume required toachieve full BOD oxidation and nitrification

(Metcalf & Eddy, et al., 2003):Note that these calculations exclude typical

design safety factors of 2.5 and are truly the min-imum. Even with the safety factors, it can be seenthat the rate-limiting step for oxidation is nitri-fication. Because of the high temperature of thewastewater, the volume required in practice is ex-tremely limited and is easily met, which is whydissolved oxygen (DO) had to be decreased tomatch the true demand. With the DO decreasedto 0.19, the total time required for full nitrifica-tion is approximately 0.167 days, or a volume of0.5 MG for the first aerobic zone. This approxi-mately matches the values seen in the field.

Process Calculation ComparisonTable 1 is a comparison of the actual

wastewater and process demands versus thedesign values of the plant. The 6-mgd designexample provided indicates what the processvalues would be if the full volume of the BNRand oxidation ditches were utilized, if the de-sign MLSS were held, and the maximum aer-ation rate were utilized. It is not intended toindicate an actual operational condition.

Operational ModificationsDue to the manner in which the recycle

pumps were installed, it is critical that nitrifica-tion is achieved in the first tank in which thewastewater enters, and that the nitrified waste-water is recycled back to the front of the tank

into the anoxic zone. This will allow for a largeamount of nitrogen conversion early and formuch of the nitrogen to leave the process as off-gas. Based on the process installed, at least twoof the zones in the influent tank (Tank 1) had tobe anoxic, and a third zone ideally would beslightly anoxic. The fourth zone then must beaerobic, with an ORP level high enough to ni-trify (not high enough to satisfy all of theCBOD5 demand) and low enough not to bleedthe aerobic environment into the fifth zonewhere the nitrogen recycle pumps sit recyclingthe nitrates. With operational trial, this level wasdetermined to be in the range of +25 to +50ORP in the fourth aeration zone by splitting airbetween the third zone and fourth zone, havingthe probe in the fourth zone. Note that theexact set point requires some trial and error andwill vary greatly based on the temperature ofthe wastewater and actual organisms present.

The second tank (Tank 2) was utilized tostabilize the wastewater, allowing for organicnitrogen conversion and additional denitrifi-cation. The air was spread uniformly with atarget ORP in the range of 0 mV +/- to keepthe wastewater active and in the anoxic range,but not overaerate it. This will allow for con-version of organic nitrogen to ammonia whichcan take time, except the nitrogen that is as-similated as solids.

The process in Tank 1 was emulated inTank 3 with slightly lower ORP set points. Tank3 would then nearly fulfill the CBOD5 demandfor the wastewater. The recycle rates are set atsimilar flow rates to allow for optimal nitrateremoval, reducing the minimum nitrogen ef-fluent to close to 6 mg/l. By satisfying the oxy-gen demand in Tank 3, Tank 4 is able to operatein a similar manner to Tank 2, stabilizing thewastewater and allowing for denitrification be-fore the MLSS goes to the clarification unitprocess for solids separation. The ORP setpoint, at the effluent of Tank 4, controls the aer-ation in Tank 4. To allow for faster and tightercontrol for the air to Tank 4, it is ideal to have afeed-forward loop by mixing the MLSS with thenitrogen recycle pump in Tank 4, as nearly alltreatment has already occurred and the penaltywill not be great, even if a “slug” is encountered.

With the volumes and aeration rates for theprocesses calculated, it was determined that,even with a significant safety factor, the oxida-tion ditches were not needed in the immediatefuture to meet effluent quality if all four tanksof the BNR are in operation. Not only were theynot needed, the effluent water quality would bebetter without them and the cost of Facility op-eration would decrease. The reason for the ef-fluent quality being better without the oxidationditches is due to the inability to “turn down” aer-ation below 60 percent of speed, or approxi-

Table 1. Calculated Process Values For Operation



mately 36 percent of aeration capability.To achieve better results and additional

recycle return, it was determined that Tanks 1,2, and 3 should be operated in parallel, andTank 4 should flow in the opposite direction,used as a completely stirred reactor and finalanoxic basin. This will allow a high ORP setpoint in Zone 4 of each tank, roughly +100mV, and the nitrogen recycle pump can be op-erated in each tank. This leads to the seven-times-influent recycle rate, and still allows thefeed-forward loop in Tank 4 to function. Fig-ure 2 depicts this proposed mode of operation.

Treatment ResultsWith the modifications to the wastewater

plants operation as described, the wastewatertreatment operators are able to achieve efflu-ent with CBOD5 at near 0 mg/l, and TKN inthe range of 1.5–3 mg/l with TN from 3–5mg/l. This is accomplished while deliveringonly about 3,000 scfm of air to the BNRprocess during peak events. While the processdesign equations indicated the recycle rate of5*Q will yield a finished quality of 6 mg/l ni-trate (Ekama, G. et al., 2008), empirical resultsfrom testing have shown that recycle rates of5*Q can yield nitrate in the range of 3 mg/l,which is approximately what has been meas-ured (Pennsylvania Department of Environ-mental Protection).

The effluent quality may not be possiblewhen the facility’s influent levels increase as thenitrogen recycle rate relative to influent will de-crease, but it can be close to that numberthrough careful monitoring of the facility.Noted items that must be monitored are theF/M ratio, along with SRT and HRT. Similar re-sults may be possible when flows approach 4.0–4.5 mgd, and it is necessary to add an oxidationditch as it will be used in series with the BNR.The target ORP values may have to decrease toprevent complete oxygen satisfaction of thetreatment process in the BNR, allowing the ox-idation ditch to operate at low speed to haveboth aerobic and anoxic zones present withinthe treatment process. If there isn’t sufficientCBOD5 remaining, the anoxic zone will not belarge enough to prevent denitrification in theclarifiers, which can be a serious issue.

Alternatively, the mode of the BNR oper-ation could be operated with Tanks 1 through 3in parallel, as shown in Figure 2 and describedpreviously. To achieve similar results at a flowof 6 mgd, BNR Tanks 1–3 could run in parallel,with relatively high ORP set points at the westend. This would keep a high recycle rate ([6mgd*3 Nrcy + 6 mgd RAS]/6 mgd-Q = 4*Q),allowing Tank 4 to operate as an effluent anoxicarea with minimal aeration provided early tokeep the mixed liquor ORP in the anoxic range

and remove nitrogen gas that may still be at-tached to solids in the process. The oxidationditches would be utilized as final polishing foradditional removal of nutrients, which wouldrequire a lower ORP set point in BNR Tanks 1–3 or a late addition carbon source. With the ex-isting oxidation ditches operating, and with arecycle rate of approximately 6 mgd each, thetotal recycle rate would be approximately 6*Q,or slightly less than the current 7*Q.

Potential Startup PitfallsOne major pitfall of the BNR process at

severe underloading can be overaerating. Dueto the capability of the BNR process to deliverair far beyond the potential demand, it is easyto overtreat the wastewater early in the BNR,with the remainder of the tank supplying airthat is not “demanded” by the organisms pres-ent. This can be seen by taking nitrogen pro-files. When operated in a series, an early tank,such as Tank 1, may have effluent with nitratesof 6 mg/l and less than 1 mg/l of ammoniagoing into Tank 2. However, Tank 3 may haveammonia at 2 or 3 mg/l, with nitrates at 12mg/l. This occurs due to ammonification and,potentially, biological nitrogen fixation, or theability of bacteria to convert nitrogen gas intoammonia or nitrate. To prevent this, the ORPcan be decreased in Tank 1, allowing more am-monia to bleed into the next tank. The processmust be more tightly controlled to prevent ex-tremely anaerobic conditions (below -50 mV)from existing in later stage tanks.

Another pitfall is undersizing the initialanoxic portion of the treatment process. If theinitial anoxic portion of the treatment processis not calculated, and it is sized too small, it maynot be sufficient in size to have meaningful den-

itrification. For example, attempting to operateTank 1 with only the first zone of Tank 1 asanoxic, or between 0.1 and 0.15 MG of anoxicvolume, resulted in nitrate levels of about 50mg/l leaving Tank 1. Further, the process had aninability of denitrifying to near the required lev-els within the process due to depleted CBOD5 inTanks 2 through 4. This was solved by movingthe aeration zones to the west and, further, byoperating Tanks 1 through 3 in parallel. By siz-ing zones properly and keeping track of key op-erational metrics of a BNR process, startup canquickly be followed by smooth operation.

References

• Goronszy, M.C., Bian, Y., Konicki, D., Jogan,M., and Engle, R., 1992, Oxidation ReductionPotential for Nitrogen and Phosphorous Re-moval in a Fed-Batched Reactor, ProceedingsWater Environment Federation Conference.

• Leschine, S. B., Holwell, K., Canaleparola, E.,1988, Nitrogen Fixation by Anaerobic Cellu-lolytic Bacteria, Journal Science, pages 1157-1159.

• Metcalf & Eddy, Tchobanoglous, G., Burton,F.L., Stensel, H.D., 2003, Wastewater Engi-neering: Treatment and Reuse, Chapter 11,McGraw and Hill.

• Ekama, G., Wentzel, M.C., Henze, M., 2008,Biological Wastewater Treatment: Principles,Modelling, and Design, Chapter 5, IWA Pub-lishing.

• Copithorn, 2002, Pennsylvania Departmentof Environmental Protection, Nutrient Con-trol Seminar, Transparency 64.

• Ott GmbH & Co., 2009, Northeast RegionalWastewater Treatment Facility Expansion,Specific Oxygen Transfer Efficiency Testing

Figure 2. Schematic Layout of Biological Nutrient Removal: Proposed Operational Mode


2014 FWPCOA OFFICERS & COMMITTEE CHAIRS

CORPORATE OFFICERS• President Jeff Poteet

(239) [email protected]

• Vice President David Denny(386) [email protected]

• Past President Raymond Bordner(727) [email protected]

• Secretary-Treasurer Rim Bishop(561) 627-2900, ext. [email protected]

• Secretary-Treasurer David Clanton(386) [email protected]

REGIONAL OFFICERSRegion 1• Director Odis Carter


• ChairNot available at press time

• Vice ChairNot available at press time

• Secretary-Treasurer Tom Walden(850) [email protected]

Region 2• Director Scott Anaheim


• Chair Josh Parker(904) [email protected]

• Vice Chair Larry [email protected]

• Secretary-TreasurerDavid Ashley(904) [email protected]

• Secretary-Treasurer-ElectRobert Boyle(904) [email protected]

Region 3• Director Wendell Maxwell


• Chair Russ Carson(321) [email protected]

• Vice Chair Kevin Shropshire(407) [email protected]

• Secretary Wayne [email protected]

• Treasurer Bobby Potts(321) [email protected]

Region 4 • Director Christina Pellegatti


• Chair Kelvin [email protected]

• Vice Chair Kimberly Ciranko(727) [email protected]

• Secretary Debra Englander(727) [email protected]

• Treasurer Janet DeBiasio(727) [email protected]

Region 5• Director Stephen Utter

(772) 978-5220 [email protected]

• Chair Brad Macek(772) 770-5045

• Vice Chair George Horner(772) [email protected]

• Secretary-TreasurerJohn Lang(772) [email protected]

Region 6• Director Phil Donovan


• Chair Pat [email protected]

• Vice Chair Vince Munn(561) [email protected]

• Secretary-Treasurer Greg Miegl(954) [email protected]

• Secretary-Treasurer-ElectPatti Brock(561) [email protected]

Region 7• Director Renee Moticker


• Chair John Feaster(954) [email protected]

• Vice Chair Nigel Harris(954) 921-3288, ext. [email protected]

• Secretary Linda Vargas(954) [email protected]

• Treasurer Laurence [email protected]

• Secretary-Treasurer-ElectTim McVeigh(954) [email protected]

Region 8• Director Jon Meyer


• Chair Justin Martin(786) [email protected]

• Vice Chair Fred Gleim(239) [email protected]

• Secretary-Treasurer Jack Green(239) [email protected]

• Secretary-Treasurer-ElectBill Smith(941) [email protected]

Region 9• Director Jim Smith


• Chair Glenn [email protected]

• Vice Chair (West) Jamie [email protected]

• Vice-Chair (East) Scott Ruland(386) [email protected]

• Secretary Frank Kelsey(386) [email protected]

• Treasurer Ron Cartwright(800) [email protected]

• Secretary-Treasurer-Elect Jeff Elder(386) [email protected]

Region 10• Director Mike Darrow


• Chair Cindy Sammons(863) [email protected]

• Vice Chair Alberto [email protected]

• Secretary-Treasurer Kather-ine Kinloch(863) 678-4182, ext. [email protected]

• Secretary-Treasurer-ElectDamon Summers(863) 678-4182, ext. [email protected]

Region 11• Director Thea Parslow


• Chair Mike Stephenson(407) 246-2213

• Vice Chair Dan Dashtaki(407) 246-2213


• Secretary-Treasurer Scott Stoll(407) [email protected]

• Secretary-Treasurer-ElectJohn Nalencz(407) 599-3563

Region 12• Director Gerry Schoonmaker

[email protected]• Chair Patrick Murphy

[email protected]• Vice Chair

John McRae Wolfe(813) [email protected]

• Secretary-Treasurer David [email protected]

Region 13• Director JM (Bud) Moody

[email protected] • Chair Stanley Young

[email protected]• Vice Chair Cameron Young


• Secretary Arnold Gibson(386) 466-3350

[email protected]• Treasurer Linda Andrews


STANDINGCOMMITTEE CHAIRSAWARDS & CITATIONS

Renee Moticker(954) [email protected]

CONSTITUTION AND RULESTom King(321) [email protected]

CUSTOMER RELATIONSNorma Corso(941) [email protected]

DUES AND FEESTom King(321) [email protected]

EDUCATIONArt Saey(954) [email protected]

ETHICSOdis Carter(850) [email protected]

HISTORICALAl [email protected]

JOB PLACEMENTJoan Stokes(407) 293-9465

MEMBERSHIPRim Bishop(561) 627-2900 Ext. [email protected]

POLICIES AND PROCEDURES

David Clanton(386) [email protected]

PROGRAM AND SHORT COURSE

Jim Smith(386) [email protected]

PUBLICITYJanet DeBiasio(727) [email protected]

SYSTEMS OPERATORSRaymond [email protected]

WEBSITEWalt [email protected]

SPECIAL COMMITTEE CHAIRSAUDIT

Tom King(321) [email protected]

EXAM CONSULTANTRaymond [email protected]

FWRJ/FWRC Tom King(321) [email protected]

LEGISLATIVEDavid Clanton(386) [email protected]

NOMINATINGRaymond [email protected]

OPERATORS HELPING OPERATORS

John [email protected]

PAT ROBINSON SCHOLARSHIP

Renee Moticker(954) [email protected]

SAFETYPeter M. Tyson(305) [email protected]

EDUCATION SUBCOMMITTEESBACKFLOW

Glenn [email protected]

CONTINUING EDUCATIONJoseph [email protected]

INDUSTRIALPRETREATMENT

Janet DeBiasio(727) [email protected]

PLANT OPERATIONSJamie [email protected]

RECLAIMED WATERScott Walden(407) 836-6865 [email protected]

STORMWATERTom King(321) [email protected]

ADMINISTRATION EXECUTIVE DIRECTOR

Tim McVeigh(954) [email protected]

TRAINING COORDINATORShirley Reaves(321) [email protected]

WEBMASTERWalt [email protected]

FWRC/FWRJ APPOINTMENTS• Third-Year Trustee Jeff Poteet


• Second-Year Trustee David Denny(386) [email protected]

• First-Year Trustee DavidClanton(386) [email protected]

• Member Rim Bishop(561) 627-2900, ext. [email protected]

• Member Tom King(321) [email protected]

• Member Al [email protected]

• Member Glenn [email protected]

For additional information on officers and committee chairs, visit the Association website at http://www.fwpcoa.org.


As I write this column we are enteringthe annual holiday season. We start theseason by giving thanks for our bless-

ings, followed by the celebration of Christmasjoy and hope, and conclude with resolutionsfor the new year. I have many blessings forwhich I am thankful, but as I look back on thelast quarter of 2013, I am particularly thank-ful for the generous spirit that is evidentamong FWEA leaders and members.

Florida Water Festival Fun!

The Third Annual Florida Water Festivalwas held once again at Crane’s Roost Park in

Altamonte Springs last October 26. I’ve at-tended every festival, and I’m pleased to reportthat this year’s was the best ever! The FloridaWater Festival continues to grow, thanks toStacey Smich of CH2M HILL and her plan-ning committee, the FWEA Public Communi-cation and Outreach Committee, the festivalsponsors, and the Central Florida Chaptermembers who volunteered to work, as well asthose who attended the event. Please read thenice article about the festival in this issue ofthe magazine authored by festival volunteerKevin Vickers of Kimley-Horn and Associates.If you have never attended the Florida WaterFestival, I highly recommend that you plan todo so this year with your family and friends! Itis a great opportunity to show thanks for theblessings of clean water that we all enjoy, buttoo often take for granted, and to educateeveryone about how we produce clean water.The Florida Water Festival will return toCrane’s Roost in October; Stacey and her teamalready have several new ideas that will ensure

that this year’s festival will be bigger and betterthan ever!

Our long-term goal for the festival incentral Florida is to grow and improve eachyear, and for more festivals to be hosted inother areas of the state. This year, the WestCoast Chapter has answered the call: it willhost the first Florida Water Festival at SpaBeach Park in downtown St. Petersburg onMarch 22. Juan Oquendo of Gresham Smithand Partners, chair of the chapter’s Water Fes-tival Planning Committee, is looking for vol-unteers and sponsors. If you are a member ofthe West Coast Chapter, or just want to help,I urge you to answer Juan’s call to service byvolunteering, sponsoring the festival, and at-tending with your family and friends. Juancan be reached at 813-440-1413 or [email protected]. Mark your cal-endars now and visit the FWEA website oftenfor updates!

Smooth Sailing Ahead

I am thankful for the support of the cen-tral Florida wastewater community that madethe first-ever technical seminar hosted by ournew Wastewater Process Committee such abig success! The seminar, titled “WastewaterTreatment from Stem to Stern: Righting theProcess Ship,” attracted a full house of 77 reg-istrants at the Polk County Utilities officesnear Winter Haven. Our thanks go out toGary Fries, Polk County director of utilitiesand FWEA Utility Council board member,and his staff, who graciously offered the useof the county’s training room for our event.Attendees listened attentively to presentationson a variety of topics, ranging from rawsewage screening system design to unconven-tional approaches to effluent disinfection thatminimize trihalomethane formation.

Committee Chair Jody Barksdale of Gre-sham Smith and Partners reported that helearned a lot while planning his first seminarand the information will be used to make fu-ture seminars even better. Planning is currentlyunderway for the second of this regional sem-inar series scheduled for May 15 in northeastFlorida in cooperation with our First CoastChapter. Later on in the fall, the seminar seriesmoves to southeast Florida, with a programtailored to wastewater issues specific to thatarea of the state. Look for details of these sem-inars on the “Events and Conferences” page ofthe FWEA website, www.fwea.org.

FWEA FOCUS

Greg ChomicPresident, FWEA

FWEA: Pausing to Give Thanks


First Coast Shootout

This past fall, our chapters were busyhosting fun networking activities for ourmembers and their guests, often in coopera-tion with members of our sister organizations.Notable among these events, our First CoastChapter, led by Chapter Chair Tim Harley ofSt. Johns County, teamed up with FSAWWARegion II to host the first annual Sporting ClayShoot on November 12. After going over basicgun safety, 44 shooters (some who had nevershot a gun before) split up in teams of four tocompete for trophies for first- through third-place team scores and top individual scores.The top team score of 272 was garnered by theCH2M HILL team of Floyd Register, BarryStewart, Mike Dykes, and Gordon Gruhn.Reese Comer, with Momberg & Comer Con-struction Services LLC, won top individualhonors with a score of 74 out of a possible 100.

Tim says that he was very pleased with thefirst-year turnout for this event and the feed-back from participants was very positive; it willonly get bigger and better as more people findout about it. The Sporting Clay Shoot prom-ises to be another fun joint annual networkingevent, along with the Don Maurer PuttingTournament held on the 18-hole natural grassputting greens at the World Golf Hall of Fame,and the Annual Golf Tournament, which ourFirst Coast Chapter members enjoy along withFSAWWA Region II members.

As mentioned earlier in this column, onMay 15, the First Coast Chapter teams up withthe FWEA Wastewater Process Committee tohost the next regional Wastewater ProcessSeminar. The seminar will be held during theday, followed later in the afternoon by whathas been called the best networking event inthe state: the Don Maurer Putting Tourna-ment. I would like to thank Tim Harley andhis First Coast Chapter steering committee forthe fine job they are doing for our members innortheast Florida!

Our New Year’s Resolution

As Florida’s go-to association for envi-ronmental water quality professionals, our res-olution for the new year is to continue to workhard for our members by hosting high-valueseminars and networking events around thestate, and we are starting the year off right withtwo outstanding training events in the monthof January.

If you are a collection system technicianand have been hoping to take the NASSCOPACP/MACP/LACP certification training, butcould not justify the high cost of travel to anout-of-state training venue, the FWEA Collec-

tions System Committee has the answer foryou. On January 21-23, the committee is host-ing the complete NASSCO certification forpipeline, manhole, and lateral assessment:Pipeline Assessment and Certification Pro-gram (16 hours), and Manhole and Lateral As-sessment and Certification Program (8 hours).All manuals, test materials and processing,break refreshments, and lunch each day are in-cluded in the $950 registration fee. Class size islimited. Unfortunately, due to NASSCO re-quirements, the registration deadline was Dec.13, 2013. But if you are interested in taking thistraining at a later date, keep checking theFWEA website for an encore of this trainingevent later in the year!

On January 30, the FWEA IntegratedWater Resources Committee will host a full-day seminar: “Sustainable Solutions Utilitiesare Implementing for Integrated Water Re-sources.” The program is packed with practicalintegrated water quality planning solutionsthat have been successfully implemented byutilities in central Florida. The high-qualityprogram is headlined by Thomas Frick,Florida Department of Environmental Protec-tion division director of environmental as-sessment and restoration, and David Childs ofHopping, Green and Sams, who serves the

FWEA Utility Council as its primary council.They will provide timely updates on regula-tory issues, including the status of the numericnutrient criteria regulations. Other speakersinclude noted experts Mark McNeal of ASRus,Steve McIntyre of Parsons Brinkerhoff,Michael Schmidt of CDM Smith, and ScottLee of AECOM; the utility perspective will beoffered by Flip Mellinger of Marion CountyUtilities, Chris Rader of Altamonte SpringsUtilities, and Robert Elmquist of Apopka Util-ities. The seminar is a great value at the $75member rate. It will be held at Second HarvestFood Bank’s spacious new conference facilityin Orlando, which has plenty of free parking.Please visit the FWEA “Calendar of Events” orthe “Conferences and Events” tabs on theFWEA website for all the details, and to regis-ter. Remember, if you are not a FWEA mem-ber, you can join online and then register atthe FWEA member rate and save $50. BothCEUs and PDHs will be provided!

In conclusion I would like to say a bigTHANK YOU! for your support of FWEAprofessional development and networkingevents. Please know that we are resolved tocontinue to earn your support by developingand offering members outstanding value foryour membership investment. ��


Patricia DiPiero

12th Annual Golf Tournament

The Southwest Chapter of the FloridaWater Environment Association joinedforces on September 27 with Region 5 of theFlorida Section of the American WaterWorks Association for the 12th Annual GolfTournament held at the Heritage Palms Golfand Country Club in Fort Myers.

The picture-perfect day drew 72 golfersand 12 hole sponsors. The tournamentraised over $3,000 and the proceeds were di-vided among the Roy Likins Scholarship,Norm Casey Scholarship, and the FloridaGulf Coast University Endowed Fund, whichwas established in 2005 by the chapter andthe Florida Gulf Coast University Founda-tion. The scholarship was awarded on No-vember 22 during the annual FGCUPresident’s Scholarship Luncheon. Thisyear’s recipient, a civil engineering student,received $700.

The Southwest Chapter would like tothank all of those who participated in an-other successful golf tournament, with all theproceeds going to supporting our futurewater and wastewater professionals.

Sixth Annual Southwest Water and

Wastewater Expo

The 6th Annual Southwest Water andWastewater Expo held last September al-lowed local water professionals and vendorsto come together for a day of training andlearning. The Expo provided continuing ed-ucation units (CEUs) and professional de-velopment hours (PDHs) to over 100registered students through five training ses-sions. Over 60 vendors were on hand to dis-play the latest equipment and services for thewater and wastewater industry. The Expoalso provides great opportunities for utilitiesand other water-related companies to high-light local projects and services.

Florida Gulf Coast University Student Chapter Events

The chapter continues to foster a greatrelationship with the FGCU Student Chap-ter. Throughout the school year, the chapterprovides “Lunch and Learn” sessions for thestudents. This is a great opportunity forthem to hear what is currently happening inthe utility, learn about real-world job expe-riences, and have an opportunity to askquestions, all while having a free lunch. Thestudents continue to participate in the Stu-dent Design Competition and our quarterlydinner meetings.

Patricia DiPiero is legislative and com-pliance programs manager with Lee CountyUtilities in Fort Myers. ��

FWEA CHAPTER CORNER

Southwest Chapter Update

Welcome to the FWEA Chapter Corner! Each month, the Public Relations Committee of the Florida Water Environment Association hosts this article to celebrate the success of recent

association chapter activities and inform members of upcoming events. To have information included for your chapter, send the details via email to Suzanne Mechler at [email protected].

SuzanneMechler

Southwest Chapter Holiday Social attendees Craig Pajer and Kirk Martin. Other Social attendees were Ron Cavalieri and Marc Lean.


Each year brings the FSAWWA a new slateof officers, a new dynamic, and a new setof challenges and opportunities to face.

All of the many resources of the section, in-cluding its finances, will be engaged: pastchairs, officers, support staff, and most im-portantly, its members. And all of these mem-bers are associated for a primary purpose:provide safe, reliable, affordable drinkingwater to their customers, the citizens of thestate of Florida. This coming year, as your newchair, I’d like to share some ideas we have andactions we’re taking to serve this purpose.

Ambassador Program

As with many associations, membershipin FSAWWA has slipped during the economicslowdown. This trend must reverse. Duringthe term of our Past Chair Jason Parrillo, theAmbassador Program was established underthe leadership of our current Chair-Elect MarkLehigh to provide outreach, primarily to util-

ities, regarding their level of participation inour section. Ambassadors have been selected,assigned to various utilities, and are currentlybeing equipped with statistics and member-ship benefit materials. As the new year begins,calendars will fill up with face-to-face meet-ings between utility officials and section am-bassadors.

I issue a call out to all of our members: Ifyou think your utility would benefit from apersonal meeting with our ambassadors,please contact Mark Lehigh ([email protected]) or Executive DirectorPeggy Guingona ([email protected]). Theywill assure that a timely meeting is scheduledwith your utility.

Mentoring Program

Now for the latest initiative: the FSAWWAMentoring Program. Our section has identi-fied a shortcoming that hurts membership re-cruitment and retention: too much timeelapses between a member signing up andthen becoming fully integrated into the asso-ciation. Those members who don’t “connect”will “disconnect.” Recruiting members must befollowed by a strong retention effort.

Opportunities abound for new membersto participate in ways that make a difference.

But connecting new members with those op-portunities hasn’t been effective for all of ournew members. A mentoring of new membersby “veterans” was chosen as the best way to fa-cilitate that effort.

At the section’s strategic planning retreatthis past October, 18 members (nine pairs con-nected as mentor/mentee) began the inaugu-ral mentoring class. They’re talking, emailing,meeting face-to-face, eating together, and mostimportantly, they’re sharing knowledge, wis-dom, and contacts. Guidelines for effectivepairings and ideas for personal contacts arebeing assembled for an expanded program be-ginning this year.

Sign-up forms for participation will beposted on the section’s website this month.Please give serious consideration to your par-ticipation as a mentor or mentee.

Also, please feel free to contact me any-time this year. I would enjoy talking with anyof our members or prospective members. Yoursection is as open as ever to new ideas to bet-ter serve our primary purpose: supplying safe,reliable, and affordable drinking water to thecitizens of Florida!

Last but not least—Jason Parrillo, youprovided great leadership this last year. Thankyou so much for your exemplary service to thesection! ��

Carl R. Larrabee Jr.Chair, FSAWWA

New Year, New Chair, New Mentoring Program

FSAWWA SPEAKING OUT

Taste Test to be Held at Florida Water Resources Conference

The Best Tasting Drinking WaterContest is held annually by the regionswithin the Florida Section of the AmericanWater Works Association (FSAWWA). Thewinners from these regional events are in-vited to participate in the statewide com-petition held in the spring at the FloridaWater Resources Conference to determinethe state’s best drinking water. The winnerfrom the state contest is then invited tocompete in the international event held atthe AWWA Annual Conference and Expo-sition (ACE) in June.

All of these events help to build ex-citement and pride within the drinkingwater industry. They offer the potential foroutreach to the public through media cov-erage of the contests, which also highlightsthe diversity of members who serve asjudges and represent a cross-section of theentire water community.

Traditionally, water utilities have beenconsidered the “silent service,” providingan essential commodity—water—everyday to their customers, in a usually contin-uous, uninterrupted manner. With today’s

ever-increasing public involvement, it isimportant to show that water utilities per-form “technical miracles” every day byproviding safe drinking water, maintainingthe public’s trust and confidence. Theseevents give the industry the opportunity toshowcase its life-giving product.

For more information about the re-gional and state contests, contact the sec-tion’s Public Affairs Council chair, JenniferMcElroy at [email protected], or PeggyGuingona, FSAWWA executive director [email protected].


The vast majority of water and sewerutilities in the United States are oper-ated by municipal governments or

local authorities. Local officials want to de-velop water and sanitary sewage systems thatwill meet the water and sewerage needs ofthe areas served by their utilities, ensure thatexisting and future utility systems are con-structed, operated, and managed at a rea-sonable cost to the users without outsidesubsidies, and develop a system that is com-patible with the area’s future growth.

The initial goal of the Clean Water Actwas to clean up the nation’s rivers andstreams through the removal of untreatedindustrial and domestic wastewaters, whichmeans that the top priority of wastewatersystems was to provide a level of servicemeeting state and federal regulatory require-ments, as well as the demands and expecta-tions of their customers. The initial focuswas on treatment plants, but once they wereconstructed, the priority shifted slightly tocombined systems, which had a propensityto overflow (sanitary sewer overflows, orSSOs) during rain events, due to hydrauliclimitations of the piping systems in com-bined sewers that were mostly in the North-

east and Midwest. Because the ratepayers bear the ultimate

cost of service, utilities usually try to developplans that will permit the utility to meet itspriorities at an affordable and stable cost forthe long term. These plans include long-termmaintenance and repair of the piping sys-tems; however, by their very nature (buriedpipes and protected facilities that are out ofthe public view), water and sewer utility op-erations are not in the forefront in the mindsof elected officials, local government man-agement, or finance personnel. Water andsewer services are viewed as basic services,which are not as “glamorous” as more visiblemunicipal services, such as industrial parks,community revitalization areas, publicbuildings, landscaping, public parks, orrecreational opportunities that gain positivecommunity headlines. Because of the tech-nical nature of water and sewer systems, theyare not well understood by local governmentofficials. The lack of obvious problems orcritical failures may lead local officials to be-lieve the water and sewer infrastructure to be“ok” as it is (Bloetscher, 2011). As a result,these piping systems may be neglected overtime.

Regulatory focus under the Clean WaterAct resulted in the development of the ca-pacity, management, operation, and mainte-nance (CMOM) program. This program isintended to ensure that sewer collection sys-tems, pumps, and wet wells are properlymaintained in an effort to eliminate sanitarysewer overflows from plugged pipes or lackof pumping capacity in lift stations. WithCMOM, pipe is inventoried and cleaningand repair work is tracked. Maintenance logsare also required for lift stations. Since keep-ing excess flows down benefits the utility fi-nancially, correction of leaks and infiltrationshould be priority projects. By reducing in-filtration and inflows into the gravity waste-water system, the utility can reduce costs atwastewater treatment plants.

The gravity collection system consists ofthe gravity pipes, manholes, service lines,and cleanouts. Collection system pipingthroughout North America prior to 1980 waspredominately vitrified clay, with polyvinylchloride (PVC) being a major pipe materialafter that. Vitrified clay pipe has been usedfor well over one hundred years because thepipe is resistant to deterioration from virtu-ally all chemicals that could be in the water,and from various soil conditions. It has along service life when installed correctly andleft undisturbed.

However, vitrified clay pipe is brittle, sosettling from improper pipe bedding, unsta-ble soil, surface vibrations, or freezing cancause the pipe to crack. Older vitrified claypipe has short joints—as small as 2 ft priorto 1920, and 6 to 10 ft prior to 1960. Fieldjoints were made prior to 1920, and evenlater. The joints were sealed with cement and

Removing One of the “I’s” from Infiltration and Inflow

Frederick Bloetscher, Dominic F. Orlando, and Ronnie Navarro

Frederick Bloetscher, Ph.D., P.E., LEED-AP,DWRE, is an associate professor at FloridaAtlantic University in Boca Raton andpresident of Public Utility Management andPlanning Services Inc. Dominic F. Orlando,P.E., is public services director, and RonnieNavarro, P.E., is a city engineer with Cityof Dania Beach.

F W R J

Figure 1. Coal tar epoxy on the outside of a manhole. Continued on page 32

cloth “diapers” wrapped around the joint.However, concrete is not waterproof and willcrack with time. The combination results inpiping with many joints, each of which hasthe potential to leak.

Temperature differences between thewarm wastewater and cooler soils can causethe exterior pipe surface to be damp. Thedampness encourages tree roots to migrateto, and wrap around, the pipe. Where cracksoccur, roots will enter the pipe. Over the longterm, the pipe will become broken and dam-aged from the roots, joint seals, and vibra-tions, and in colder climates, from freezing.When the pipe is submerged, like it is inmost of Florida, the pipe will constantly leak;

this is termed “infiltration.” Infiltration in-creases the base flow and will often be indi-cated by low-strength wastewater duringroutine tests. However, it generally does notlead to peak flows.

As costs to treat and pump wastewaterhave risen, much of the focus has been ondealing with removal of infiltration; one stepin this process is sealing manholes. Manholesare traditionally precast concrete or brick,with brick being the method of choice untilthe 1960s. Brick manholes suffer from thesame problems as vitrified clay sewer lines:the grout is not waterproof so it can leak sig-nificant amounts of groundwater. Precastconcrete manholes resolve part of this prob-lem, but concrete is not impervious either.

While elastomeric or bituminous seals areplaced between successive manhole rings, theconcrete is still exposed. Many utilities willrequire the exterior of the manholes to havea coal-tar or epoxy covering, which helps tokeep water out (see Figure 1). Lining the in-terior is of some value, but not nearly asmuch as coating the outside prior to backfill.

The major focus to remove infiltrationhas been, and continues to be, oriented tolining gravity pipe, which includes a signifi-cant amount of televising to find leaks. Tele-vising the sewer system and sealing andlining sections where leaks are noted is com-mon; however, many miles of videotapeshow virtually nothing, but with significantmoney spent. Part of this is because “infil-tration” and “inflow” are not the same, andstorm events do not highlight infiltrationnearly as much as inflow. The U. S. Environ-mental Protection Agency (EPA) has estab-lished infiltration criteria depending on thefootage of collection sewer in an area as fol-lows:

Table 1. EPA Infiltration Allowance(Bloetscher, 2011)

Sewage Footage Allowance Range(ft.) (gpd/in-mile)

> 100,000 2,000-3,00050,000-100,000 3,000-5,000

1,000-50,000 5,000-8,000

The criteria in Table 1 are used as a pri-mary indicator for the assessment and clas-sification of collection system infiltration,but it should be noted that, for even largesystems, the criteria may indicate 35 percentinfiltration in the total wastewater flow, andit fails to separate inflow.

Separating Inflow and Infiltration

Where there are peaks in wastewaterflows that match rainfall, inflow would ap-pear to be a more likely candidate for thecause of the peaks than infiltration frompipes that are constantly under the watertable. Storms highlight the need to reduce in-flow into the collection system so as not tooverwhelm the piping system hydraulically,causing plant damage or sewage overflowsinto streets because inflow results from a di-rect connection between the sewer systemand the surface. The removal or accidentalbreaking of a cleanout, unsealed manholecovers, laterals on private property, con-nected gutters or storm ponds, damagedchimneys from paving roads, or cracking of

Figure 3. Identification of inflow, infiltration, and base flow in a sewer system flowhydrograph.

Figure 2. Indication of inflow to the sewer system. (Bloetscher, 2011)



the pipe may be a significant source of inflowto the system, which can be identified easilyduring storm events.

Figure 2 shows a typical graph of rain-fall versus flow for a given utility. The peak-ing that correlates with the rainfall is inflow,not infiltration, since infiltration is part ofthe base flow that creeps upward with time.Infiltration looks much like the base flow.For the utility in Figure 3, the average dailywater is just over 2.05 mil gal per day (mgd),but the wastewater flow is over 3.8 mgd, in-dicating nearly 1.2 mgd of infiltration. Whenplant operators and engineers see peaks inflows after rain events, this is not indicativeof groundwater infiltration; it is indicative ofactive connections from the surface to thepiping system, which is inflow. The goodnews is that simple, low-tech methods can beused to detect inflow, which should be theprecursor to any infiltration investigation.

Resolving the Inflow Problem

Ongoing testing of the influent andmonitoring of the lift stations by a utilityprovides a measure to determine whether in-appropriate amounts of inflow are going tothe wastewater plant. This testing can take avariety of forms, such as a review of lift sta-tion run times, followed by analyses of theinfluent wastewater quality. Low-strengthwastewater is an indication of both infiltra-tion and inflow problems, and low-strengthwastewater during dry periods is infiltration;during wet events, it could be both.

Resoling Inflow

Resolving the inflow problems isstraightforward, and from a utility stand-point, the more benefit that can be gainedper dollar spent, the better. Lessening poten-tial regulatory actions from overflows is alsoa risky issue to address. Both indicate that in-flow should be the first priority, followed bytraditional televising and lining projects.

Inflow can be resolved in an orderlyfashion. The following outlines a basic pro-gram for inflow detection and correction forany utility system. The order of implemen-tation is important, and pursuing all steps inorder will resolve the majority of inflow is-sues, while permitting the utility to target thespecific areas where infiltration is a problem.The program as outlined also minimizes un-needed videotaping of the collection systemand permits more dollars to go toward fix-ing problems.

The first step is inspection of all sanitarysewer manholes for damage, leakage, or

other problems, which, while seeming obvi-ous, is often not the case. The manhole in-spection should include documentation ofcondition, global positioning system (GPS)location, and some form of numbering if notcurrently available. Use of a geographic in-formation system (GIS) database, with ties

to photographic data, is a useful addition.Most manholes have limited condition is-sues, but where the bench or walls are inpoor condition, they should be repaired withan impregnating resin. Deterioration may bean indication of wastewater quality concerns,

Figure 4. Installation procedure. (photos: USSI Inc.)



requiring the addition of chemicals to reducethe impact of hydrogen sulfide.

Next is the repair and sealing of chim-neys in all manholes to reduce inflow fromthe street during flooding events. The chim-ney includes the ring, cement extensions, liftrings, brick, or cement used to raise the man-hole ring. Manhole covers are often dis-turbed during paving or as a result of traffic.

Temperature, vibration, and traffic can breakthe seal between the steel ring and concrete.The crack between the ring and cover canleak a lot of water, as demonstrated by aMiami-Dade County test conducted severalyears ago (Miami-Dade 2010). The intent ofthe chimney seal is to prevent inflow fromthe area beneath the rim of the manhole, butabove the cone. To properly seal the system,a flexible polymer based coating, installed in

accordance with the following procedure,should be used (see Figure 4):1. Remove all loose mortar, concrete brick,

or other materials, as they will interferewith seal performance and adhesion.

2. High-pressure sandblast the chimney andring to create a dry, clean surface, freefrom dust and moisture.

3. Apply a primer coat to the clean chimneymaterial in accordance with manufacturerinstructions.

4. Allow the primer to cure as specified bythe manufacturer prior to application oflining material.

5. Apply the lining material on top of theprimer in accordance with manufacturerinstructions. The lining material shouldbe flexible but resistant to account forsurface loading, temperature, and vibra-tional changes that create most chimneydamage.

6. The primer and lining should have a fin-ished, dry thickness greater than 120 mL.

The following outlines a typical specifi-cation for the primer and seal:

Primer coat� Specific gravity > 1.0� >90 percent solids as measured by ASTM

D2369� Elongation 650 +/- 50 as measured by

ASTM D412� Adhesive strength > 700 psi on steel or

concrete as measured by Eclometer 109� Tensile strength = 3200 +/- 50 psi as

measured by ASTM D412� Tear resistance =325 +/- 10 psi as meas-

ured by ASTM D624� Nonflammable as measured by ASTM D-

93 in a Pensky-Martens closed cup� Temperature range -65 to 200 F � Minimal water absorption capacity (<0.5

percent)

Top Coat� Specific gravity > 1.0� >99 percent solids as measured by ASTM

D2369� As applied, solids greater than 70 percent� Ultimate elongation equal to or greater

than 850 percent +/- 50 as measured byASTM D412

� Elongation as applied equal to or greaterthan 335 percent +/- 10 as measured byASTM D412

� Adhesive strength > 700 psi on steel orconcrete as measured by Eclometer 109

� Tensile strength = 2000 +/- 50 psi asmeasured by ASTM D412

Figure 5. Inflow defender manhole rain dish showing installed dish, and both poly-carbonate and polyethylene versions. Note the ribs and depth of dish that improveslong-term strength. Note polycarbonate is required for newer, 30- or 48-in. manholecovers. Texas has mandated 30-in. holes for new manholes. Only stainless steel andpolycarbonate are available in the larger sizes.

Figure 6. Smoke Test. (photo: USSI Inc.)




� Tear resistance =300 +/- 10 psi as meas-ured by ASTM D624

� Nonflammable as measured by ASTM D-93 in a Pensky-Martens closed cup

� Temperature range -65 to 200 F � Minimal water absorption capacity (<0.5

percent)� Shore A hardness equal to 75 +/- 5 as

measured by ASTM 2240

The next step is to put dishes into themanholes. One might think that only man-holes in low lying areas get water into them,but surprisingly, every manhole dish, evenone that is properly installed, has water in it.Hence, it must be assumed that all manholesleak water between the rim and the cover.

Most collection system workers are fa-miliar with dishes at the bottom of the man-hole, where they are of limited use. This isbecause those dishes deform when filled withwater or are constructed is a manner that al-lows them to be knocked in when the cover isflipped. The solution is a deeper dish with re-inforcing ribs and a gasket. Figure 5 showstwo examples (note the man standing in theupside-down dish). The dishes shown aremade of a polycarbonate (shiny) and a poly-ethylene copolymer material that meet therequirements of Underwriters Laboratories(UL) Standard 94-HB and American Societyfor Testing and Materials (ASTM) specifica-tion Prime HDPE 250 to be suitable for at-mospheres found in manholes. Thepolymer-based dishes eliminate the dissimi-lar metals issues with stainless steel dishesand are available at a lower cost. The key isthe appropriate reinforcing to prevent dishesfrom dropping into the manhole. The gasketseal should be made of a closed-cell neo-prene material with pressure sensitive adhe-sive on one side for adhering to the dishbody, and be a minimum of ½ in. wide and0.125 in. thick. As the standards for man-holes gets larger (Texas rules are now 30 in.),only stainless steel and polycarbonate areavailable options.

To ensure the manhole dishes meet thesystem needs, a test can be run to evaluatedishes. Miami-Dade County tested dishesusing the following procedure three timeseach, where the average drain time was usedin the calculations of inflow rates (MiamiDade, 2010):

� Apply 2 ft of head pressure to the MHframe and cover.

� Document the time it takes the water todrain through the opening between theframe and the cover.

Figure 8. Areas where further infiltration investigation via televising is needed (only15 percent of the system).

Figure 7. LDL Plug De-sign. (photo: USSI Inc.)




� The volume of the water in gal and thedrain time is used to calculate an inflowrate.

The following scenarios were tested (nodish, standard dish, reinforced dish with gas-ket): � No insert inflow rate: 5.45 gal per minute

(gpm)� Standard insert inflow rate: 0.72 gpm � Inflow Defender Manhole Inflow Dish®

(reinforced with gasket): 0.002 gpmMiami-Dade County chose the latter

dish for obvious reasons. Similar tests shouldbe done in other locales.

Once the manholes are sealed, smoketesting can identify obvious surface connec-tions (see Figure 6). The normal protocol forsmoke testing will identify broken or miss-ing cleanout caps, surface breaks on publicand private property, connection of guttersto the sewer system, and stormwater connec-tions. All should be documented via photo-graph, by associated address, and public orprivate location. The public openings atcleanouts can be corrected immediatelyusing utility funds; the contractor can in-clude this cost to make immediate repairs inthe bid documents. However, if the cleanoutis broken, it may indicate mower or vehicledamage that can occur again. If missing, theresident may be using the cleanout to drainthe yard (more common than realized). Ineither case, the collection system needs to beprotected. Utility Sealing Services Inc.(USSI) in Venice developed a solution, calledthe LDL plug, consisting of the following(see Figure 7):� A molded, one-piece, synthetic urethane

polymer material plug body designed toalign and seal the cleanout.

� Inner seal of the plug shall consist of aPVC material fabricated with an internaltapered, beveled seat, with a thickness of0.187 in. and overall height of 1.25 in.

� Embedded retrieval hasp and hardwareshould protrude at least 1 in. above theplug body, have a thickness of 0.187 in.,and have hardware molded into the plugbody using corrosion-resistant material toallow removal by utility crews from thesurface.

� Plug has embedded steel to permit surfacedetection by a metal detector.

Installation in the vertical riser of thecleanout is undertaken as follows:� Remove cleanout cap (broken or other-

wise).� Wipe all cleanouts to remove soil and

moisture from the interior of cleanout

stack as they would interfere with theplug.

� Scuff the interior of stack with emerycloth.

� Swab interior scuffed area with PVC cleaner.� Swab exterior of inner seal ring of plug

with PVC cleaner.

Figure 10. Comparison of flows in October of 2011 at Dania Beach and aneighboring system. Note the spikes on the same neighboring system versus the lackof large spikes in Dania Beach. The gradual upticks are likely groundwater levelscreating infiltration.For Dania Beach, the 5-in. storm raised flows less than 0.5 mgd.

Figure 9. Comparison of flows in December of 2009 at Dania Beach and aneighboring system. Note the big spike after the rainfall that was not present on thesystem with limited rain (13 in. increased flows by over 2 mgd).



� Apply PVC glue to interior walls ofcleanout and exterior of inner seal ring ofplug.

� Slide inner seal ring into appropriatepoint in cleanout, align with depth gaugeinstallation tool, and twist to glue in place.

Notices should then be sent to propertyowners with documentation of the inflowconnections to their properties. This issometimes the most difficult part of the pro-gram due to political considerations, but itis necessary.

The final step is a low-flow investiga-tion, which is intended to target the infiltra-tion piece of the problem. Such an event willtake several days and must be planned to de-termine the priority manhole to start with,and the sequencing. Based on a projectedplan, the following protocol is based onwhere there is and isn’t flow:� Open the manholes.� Inspect them for flow.� Determine if the flow is significant. If flow

exists, open consecutive manholes up-stream to determine where flow is de-rived. Generally, a 2-in.-wide bead ofwater is a limit of “significant” infiltra-tion.

Figure 8 is an example from DaniaBeach. After 20 years of no investigation,only 15 percent of the pipe segments indi-cated infiltration leakage. This reduced the

televising and lining portion of its liningprogram by over $1 million, which morethan paid for the inflow reduction project.

Results

So, the question is: What is the cost, andhow successful is this type of protocol? TheCity of Dania Beach pursued this programfor its inflow correction to identify where in-filtration efforts should be concentrated. Theservice area consisted of 800 manholes, andthe total cost was $480,000, which includedfixing 25 manholes, sealing all 800 manholesand dishes, repairing 200 public inflowopenings, identifying 300 private connec-tions, and conducting two smoke test eventsand one midnight run.

In the past, the City of Dania Beach in-curred substantial peaks from “normal” rain-fall events. Figure 10 shows the City ofDania Beach and a neighboring communityin December 2009, when the rainfall on oneday was over 13 in. (although it was only 2.5in. the neighboring community). Significantflooding on the east side of Dania Beachlasted three weeks, in part because the sewersystem was sealed on public property, butopenings remained on private property. Fig-ure 11 shows October 2011, when 13 in. ofrain fell during the month, including 3.5-and 5-in. storms a week apart. While thedata is given on a daily basis, it is clear thatthe Dania Beach system did not incur thesustained peaks of the past, although infil-

tration remains an issue (currently undercontract).

The cost to treat wastewater averages$3.50/1000 gal. The City of Dania Beach hasestimated it saved 200,000 gal per day (gpd)over the course of a year as a result of its in-flow correction effort, while substantially re-ducing its peaks; this is a savings of over$250,000 per year. Payback is under twoyears.

In addition, Figure 10 shows the limitedareas for televising to correct infiltration, thenext phase of Dania Beach’s program. Only15 percent of the system had infiltrationidentified, and this is 20 years after the last“I and I” correction effort. Full television in-spection would have revealed nothing in 85percent of the system. An estimated 800,000gpm of inflow existed in the yellow pipes,which will yield substantial additional sav-ings. This effort has shown that investmentin infiltration and inflow reduction by theutility should provide confidence that it willsee reductions in inflow to the wastewatertreatment plant, and reductions in its oper-ating costs.

Most specifics can be discovered whendaily flow information is compared in agiven area before and after inflow repairs arecompleted. Cooper City, located in BrowardCounty, decided to pursue a pilot inflow re-duction program in spring 2012. Data for2011 and 2010 were compared to determinehow different the results were. Figure 11shows a comparison of pump times andrainfall (x 1000 for ease of graphical com-parison) for 2011 and summer 2012. Thegraphic does not show conclusive data, butbreaking the information down is more illu-minating. Figure 12 shows the same lift sta-tion with rainfall versus pump run time in2011. This was done for three lift stations inthe area, addressed with inflow correctionfor both 2011 and 2012.

More informative would be a graph ofrainfall versus pump time for specific stormevents; the concept is to determine if there isless run time post-inflow correction. The re-sults will show, on a line sloped for a rela-tionship, a greater slope, meaning morepump run time for a given rain event. Thedata were combined for the lift station basins(52 to 54) to find similar storm events eachyear; only these values were compared. Fig-ures 13 to 15 show a comparison of specificrain events versus pump run time. In eachcase, the slope of the line through the 2011values is substantially above the slope of the2012 rain events. For lift station 52 and 53,the pump run times do not change signifi-cantly, regardless of rain totals, indicating

Figure 11. Comparison of Cooper City lift station area flows before and after the G7 program in one of four lift station basins (typical).



that for this basin, most of the inflow hasbeen removed (Figures 13 and 14). In the liftstation 54 basin, the 2012 line is nearly flat,and there does not appear to have been asmuch inflow in this basin in 2011. Still achange in the slope is noted (Figure 15).

The results of the two case studies showsthat inflow is separate from infiltration, thepeaks in flows are inflow and can be removedrelatively easily, the costs are reasonable, andthe solutions relatively simple. Getting the

right technology and specifications is im-portant. Correcting inflow helps utilitiestarget the specific lines where infiltrationcorrection is needed, negating the televisingand cleaning of miles of pipe where no dam-age is found. This saves the utility money aswell. Overall, correcting inflow first willlikely reduce the overall cost of infiltrationand inflow correction, and bring a greater re-turn on invested dollars in the form of re-duced flows.

References

• Bloetscher, Frederick (2011), Managementfor Water and Wastewater Operators, AmericaWater Works Association; Denver, Colo. ��

Figure 12. Rainfall (x 1000) versus pump run time. Correlation for run time and rainfall was 0.5.

Figure 13. Comparison of rain events (in.) versus pump runtimes in 2011 and 2012 for Cooper City Lift Station 52. Theslope of the lines show that the inflow correction substantiallyreduced inflow. The 2012 graph shows virtually no effect ofrainfall on run times.

Figure 14. Comparison of rain events (in.) versus pump runtimes in 2011 and 2012 for Cooper City Lift Station 53. Theslope of the lines show that the inflow correction substantiallyreduced inflow. The 2012 graph shows virtually no effect ofrainfall on run times.

Figure 15. Comparison of rain events (in.) versus pump runtimes in 2011 and 2012 for Cooper City Lift Station 54. Theslope of the lines show that the inflow correction reduced inflow.


The South Cross Bayou Water Reclama-tion Facility (SCBWRF) in PinellasCounty was originally constructed in

1960 with a 15-mil-gal-per-day (mgd) averagecapacity. A 12-mgd expansion and other im-provements were implemented in the 1970sand 1980s. In 2004, the County completed aproject to expand the facility to an averageflow of 33 mgd, with a peak hourly flow of 66mgd. Effluent from the facility is currently dis-infected with chlorine gas, and on average, 20to 30 percent of the effluent is discharged viasurface water to the Joe’s Creek outfall, a ClassIII water body, with the remaining used forbeneficial reuse.

In 2010, the County entered into a con-sent order with the Florida Department of En-

vironmental Protection (FDEP) that requiredthe surface water discharge from the facility viathe Joe’s Creek outfall to meet regulatory lim-its by June 30, 2013 (subsequently amended toSept. 30, 2014), for trihalomethanes (THMs),which are disinfection byproducts (DBPs) ofchlorination. Specifically, water discharged toJoe’s Creek must contain less than 34 micro-grams per liter (µg/L) of chlorodibro-momethane (CDBM), and less than 22 µg/L ofdichlorobromomethane (DCBM). Both limitsare running annual averages (RAA) based ongrab samples collected monthly. These limitsdo not apply to the reuse and land applicationsystems.

In order to meet these limitations, a newadvanced disinfection system consisting of

high-level ultraviolet (UV) disinfection forsurface water discharges was planned and de-signed. Due to a tight consent order compli-

Incorporation of High-Level Ultraviolet Disinfection to Meet Stringent Effluent

Discharge Disinfection Byproducts Limits

Lynn Spivey, Sean Chaparro, Steve Schaefer, and William Harrington

Lynn Spivey is principal engineeringconsultant and Sean Chaparro, P.E., issenior environmental engineer withARCADIS-US Inc. in Tampa. SteveSchaefer, P.E., is principal engineer withParsons Water & Infrastructure Inc. inTampa. William Harrington, P.E., isengineering support services supervisor—planning and design section, with PinellasCounty.

F W R J



ance schedule, only prevalidated UV systemsfor reuse applications were considered, and aprepurchase of the selected UV system wascompleted to ensure that the tight complianceschedule could be met. The new UV system iscurrently under construction and will beretrofitted in the facility’s existing automaticbackwash filter basins.

This article discusses the methodologyand results of the evaluation completed to con-firm the required UV system capacity and theassessment of the major available prevalidated

UV systems that will meet the high-level disin-fection requirements of the facility. To mini-mize costs, a split stream treatment approachwas used, where the UV system would onlytreat a portion of the flow and then be blendedwith the chlorinated/dechlorinated streamprior to discharge. Various UV system capaci-ties were assessed to determine the “optimum”UV system capacity that will meet disinfectionrequirements at a UV transmittance (UVT)below the minimum prevalidated level, and en-sure that the blended stream can comply withthe running annual average surface water dis-

charge DBP limits. Provisions included in thecontract documents to verify and confirm thatthe UV system will meet disinfection require-ments at a design UVT below the minimumprevalidated levels are also presented.

Establishing the Design Ultraviolet Transmittance

For a UV system, the design UV dose is anindicator of the amount of pathogen reductionthat this system will achieve under the most chal-lenging design conditions. During validationtesting, specific UV doses are determined, whichrepresent the UV dose distribution of a specificUV system and account for the inherent vari-ability of UV intensity and hydraulics. The Na-tional Water Research Institute (NWRI) hasdeveloped guidelines to establish the ability ofcommercial UV systems to deliver specific UVdoses in a standardized way (Second Edition ofthe NWRI Guidelines for Drinking Water andReuse, or 2003 NWRI Guidelines). Most UVequipment manufacturers validate their UV sys-tems in general accordance with these guidelines.

The UVT is by far the most important waterquality parameter used for sizing UV systems.The UVT is a measurement of the UV light’s abil-ity to penetrate the water, which is necessary toinactivate pathogens. Lower UVT values signifythat UV light will travel shorter distances beforeattenuation; this means that more UV light willbe required in order to achieve a given design UVdose. As such, selection of a UVT design value iscritical due to its impact on disinfection efficacy,system size, footprint, capital costs, and operationand maintenance (O&M) costs.

Regarding reuse applications that requirehigh-level UV disinfection, the FDEP hasadopted by reference the 2003 NWRI guide-lines. For high-level disinfection of granularmedia filtration effluent, these guidelines rec-ommend the use of a minimum design doseof 100 mJ/cm2 and UVT254 value of 55 percent,or alternatively, a design UVT254 value corre-sponding to the 10th percentile of a set of datacollected at least three times a day over a min-imum period of six months.

In accordance with these guidelines, theSCBWRF installed an on-line UVT analyzerand started collecting real-time UVT data inthe fall of 2010. Each hourly value was aver-aged by the plant supervisory control and dataacquisition (SCADA) system logic from theon-line UVT analyzer continuous output sig-nal; 24 hourly average UVT254 values were thusgenerated each day. Figure 1 shows a chrono-logical graph of the average hourly UVT254 val-ues. As seen since the start of the UVT254

collection program, there has been a generaldownward trend, with occasional prolonged


Figure 1. Average Hourly UVT Value

Figure 2. Cumulative Frequency of UVT – Average Hourly Data


UVT dips, followed by recoveries. The UVTvalues have ranged between 40 and 75 percentthroughout the monitoring period.

This data set was subsequently used to de-termine a design UVT254 value based on the10th percentile approach as outlined in the2003 NWRI guidelines. The data set of aver-age hourly UVT254 values from Oct. 1, 2010, toNov. 18, 2011, was ranked in ascending orderrelative to the entire data set range, creating acumulative frequency graph. Figure 2 is the re-sult of this analysis. As seen in the figure, the10th percentile value recommended for designby the 2003 NWRI guidelines was 51 percent.This design UVT is lower than what would beanticipated from a facility with tertiary treat-ment and lower than the minimum 55 percentUVT that has been prevalidated for any high-level UV disinfection system.

A detailed review of operating data foundcorrelations between the low UVT254 valuesand rainfall, plant flow, and effluent total or-ganic carbon (TOC). The general relationshipamong these parameters is that rainfall causeshigh flows to enter the plant, in turn inducingan increase in TOC, with an associated de-crease in UVT254. Only a slight correlation be-tween lower UVT254 and higher effluent nitratewas observed. The levels of TOC and nitratemay be a direct consequence of an upsetwithin the plant process at times of high flow.

A broad-level process review and opera-tional shadowing of the SCBWRF was subse-quently completed to identify potentialopportunities to enhance the UVT throughbasic process changes within the existing treat-ment scheme. The process review and opera-tional shadowing identified a number ofprocess changes that may help improve treat-ment performance and increase UVT. How-ever, identified changes were not used tochange the design UVT of 51 percent, but in-stead were recommended for implementationas a long-term strategy to optimize system per-formance, increase UVT, and reduce operat-ing costs of the UV system when operational.

To assure the FDEP and Pinellas Countythat the UV system can meet disinfection re-quirements at a low design UVT of 51 percent,the selected UV manufacturer was required aspart of its contract agreement to:� Provide a performance guarantee based on

permitted effluent limits. � Complete site-specific computational fluid

dynamics (CFD) modeling of the systems andproviding detailed calculations and backupdocumentation demonstrating how the UVsystem would be sized to meet the designUVT of 51 percent based on validation dataat 55 percent (there is a systematic, validated


relationship between UVT and UV dose). � Maintain conservative safety factors

throughout design (validate with MS2, aconservative challenge organism; design forworst-case scenario, such as lamp aging andfouling factors; and provide a redundant

UV bank in each channel).� Successfully complete 21-day performance

testing at startup. Performance testing willinclude checkpoint bioassay testing and fecalcoliform reduction testing to confirm thatthe correct UV dose is applied and disinfec-tion requirements are met. Flow-split testing

will also be required to verify that an evenflow-split is achieved among UV channels.

Determining the Required Ultraviolet System Capacity

The required UV system capacity for theSCBWRF was evaluated based on several factors: � DBP effluent limits.� Historical DBP concentrations (October

2009 through 2011), which best representoperational conditions for the future UVsystem. The DBP data prior to this was notincluded due to plant improvements madein mid-2009, which successfully reducedand consistently maintained DBP levels.

� Historical surface water discharge (SWD)flows (October 2010 through November2011).

� Historical rainfall and reclaimed system de-mand (seasonal).

� System cost.

As previously indicated, the UV systemwas not sized to handle the entire permittedsurface water discharge flow (20 mgd). To min-imize costs, a split stream treatment approachwas used, where the UV system would onlytreat a portion of the surface water dischargeflow. The tertiary-treated effluent would besplit into two streams: one would be chlori-nated/dechlorinated, while the other streamwould be disinfected using UV. The UV-disin-fected effluent would have a DBP concentra-tion of 0 mg/L and would be blended with thechlorinated/dechlorinated tertiary effluentstream downstream of dechlorination beforedischarge to Joe's Creek. To determine the op-timal UV system capacity, a range of flows wereevaluated that would meet the annual averageDBP limits upon blending prior to surfacewater discharge. The following two overall op-erational protocols were evaluated:1. Year-round operation. Operating the UV sys-

tem year round for a selected UV system ca-pacity. Flows within the UV system capacitywill be discharged to Joe’s Creek with zeroDBPs.

2. Seasonal operation. Operating the UV sys-tem on a seasonal basis for a selected UVsystem capacity. For this scenario, the UVsystem would operate during periods of theyear when the UVT is at or above a selectedUVT value. During periods when the UVTis below the set point, the UV system wouldnot operate and the entire SWD flow wouldbe disinfected by chlorination prior to dis-charge. To determine the period where theUV system would not be operational, thedata set was assessed for months thatshowed the UVT below the design value. For


Figure 3. Year-Round UV System Operation DBP Concentrations Versus UV System Capacity

Figure 4. Seasonal UV System Operation DBP Concentrations Versus UV System Capacity


the data set of October 2010 through No-vember 2011, it was determined that the UVsystem would not be operational during themonths of July, August, and September.

Due to the overall variability and limitedamount of data available, future flows were esti-mated by assuming maximum monthly surfacewater flows based on historical data. The DBPconcentrations were estimated by assuming the90th percentile historical concentrations. Thetarget concentrations for each permitted DBPare 80 percent of the current permit limits. Thus,for the various UV system capacities presentedin the analysis, and for surface water discharge(SWD) flows greater than the UV system size,the blended DBP concentration was determinedusing following equation:

90th Percentile DBP Concentrations (µg/L):

Chlorinated Flow (mgd) * Average 90th per-centile DBP concentration for data set (µg/L)SWD (mgd)

The resulting capacity analysis for boththe year-round operation and seasonal opera-tion based on the analysis described are shownin Figure 3 and Figure 4.

In order to stay below 80 percent of theannual average DBP permit limits, a capacityof 10 mgd is required for year-round treat-ment. For seasonal treatment, a capacity of 13

mgd is required. The increase for seasonaltreatment is due to the higher influent andlower reclaimed flows at this time. It should be

Figure 5. Estimated DBP Concentrations for an 8 mgd UV System




noted that this particular seasonal treatmentanalysis had high rainfall and correspondinghigh SWD for the months of July through Sep-tember, but could vary considerably depend-ing on the weather (rainfall) in southwestFlorida. In addition, DBP formation is influ-enced by temperature, and during the sum-mer, when the UV system is not operational,the potential for DBP formation is the highestdue to the high temperatures. Therefore, year-round treatment may not always be more ef-fective than seasonal operation. A UV system

size of 10 mgd would provide the flexibility toutilize either operational option to meet theDBP regulatory effluent limits, depending onthe rainfall and amount of time the UV sys-tem is not operational. There is potential thatoperating on a seasonal basis may result inDBPs closer to the permitted limits.

To better illustrate the seasonal variationand implications throughout the entire yearfor the various system capacities, graphs wereprepared to show the estimated daily surfacewater discharge DBP concentrations, the run-ning annual DBP concentrations, SWD, and

UVT based on the calculations and assump-tions outlined . Figures 5 through 7 show themodeled DBP concentrations (based on theinformation and assumptions presentedabove) for year-long operation for UV systemcapacities of 8, 10, and 12 mgd.

As shown in the graphs, the number ofdays with DBP concentrations above 80 per-cent of the limits increases as the system sizedecreases. The RAA for the estimated DBPconcentrations are below the permit target forthe entire year for the 10- and 12-mgd capac-ities. This analysis shows that a UV system ca-pacity above 10 mgd may be too conservative,since only a few days per year are projectedabove the limits. The results also show that aUV system capacity of 8 mgd will result inprojected DCBM and RAA concentrationsabove the target limit during the high flow pe-riod. Based on these results, the UV systemwas designed for a capacity of 10 mgd, whichshould provide sufficient treatment capacityto ensure that effluent DBP concentrations ofthe blended flow stay within the DBP effluentlimits. The UV system design also provides theflexibility necessary to increase system capac-ity in the future, if needed or desired by theCounty, by providing room for additional UVchannels and required equipment.

Comparison of Prevalidated Ultraviolet Systems

A detailed review of the major prevali-dated UV systems available for high-level dis-infection of the SWD at the SCBWRF wasconducted to identify and compare the mainsystem characteristics, design criteria, and es-timated capital and O&M costs for each of theUV systems. The UV systems evaluated in-clude systems from Trojan, Ozonia, andWEDECO, all of which have been accepted bythe California Department of Public Health(CDPH) and FDEP for high-level disinfectionapplications. Calgon, another major UV man-ufacturer, did not participate in this initial as-sessment. The lamp orientation of the UVsystem (i.e., vertical, Ozonia versus horizontal,Trojan, and WEDECO) was an important con-sideration in evaluating the UV systems, sinceit has a significant impact on the requiredstructural modifications to retrofit the mod-ules within the existing filters, maintenance re-quirements, and overall capital and O&Mcosts.

Table 1 summarizes and compares the keydesign criteria, features, and maintenance re-quirements of the Trojan, Ozonia, andWEDECO UV systems evaluated. Table 2compares the capital, annual O&M, and pres-

Figure 7. Estimated DBP Concentrations for an 12 mgd UV System

Figure 6. Estimated DBP Concentrations for a 10 mgd UV System




Table 1. Comparison of Ultraviolet Systems

ent-worth costs for each of the UV system al-ternatives.

Selected Ultraviolet System

Based on the technical, maintenance, andcost evaluation of the various UV systems, dis-cussions with Pinellas County technical andmaintenance staff, and site visits to various op-erating UV disinfection systems run by othermunicipalities in Florida; the selected UV sys-tem for the SCBWRF was the vertical array UVsystem Aquaray 40HO, manufactured by Ozo-nia. This system was selected due to the fol-lowing distinguishing characteristics:� Greater ability to manage fluctuations in

liquid level due to the vertical lamp arrayconfiguration.

� Faster lamp startup time due to the type oflamp used.

� Ease of lamp replacement since modules donot need to be removed to replace lamps.

� Ease of downturn and flexibility of operationbecause of the ability of the system to turnoff individual rows of lamps within a mod-ule and provide faster ramp up capabilities.

� Lower life cycle costs. ��

Table 2. Ultraviolet System Cost Comparison Matrix



Earn CEUs by answering questions from previous Journal issues!

Contact FWPCOA at [email protected] or at 561-840-0340. Articles from past issues can be viewed on the Journal website, www.fwrj.com.

Members of the Florida Water &Pollution Control Association (FWPCOA)may earn continuing education unitsthrough the CEU Challenge! Answer thequestions published on this page, based onthe technical articles in this month’s issue.Circle the letter of each correct answer.There is only one correct answer to eachquestion! Answer 80 percent of thequestions on any article correctly to earn0.1 CEU for your license. Retests areavailable.

This month’s editorial theme is

Wastewater Treatment . Look aboveeach set of questions to see if it is forwater operators (DW), distributionsystem operators (DS), or wastewateroperators (WW). Mail the completedpage (or a photocopy) to: FloridaEnvironmental Professionals Training, P.O.Box 33119, Palm Beach Gardens, FL33420-3119. Enclose $15 for each set ofquestions you choose to answer (makechecks payable to FWPCOA). You MUSTbe an FWPCOA member before you cansubmit your answers!

Operators: Take the CEU Challenge!

1. In 2010, municipal wastewater treatment facilities consumedabout ______ of United States electrical demand.a. 4,000 kWh b. 25 million kWhc. 1.5 percent d. 60 percent

2. ___________ bacteria are autotrophic organisms capable ofconverting a mixture of ammonia and nitrite directly tonitrogen gas.a. Nitrifying b. Denitrifyingc. Annamox d. Aerobic

3. Which of the following is identified as a “separate” sidestreamtreatment process?a. InNitri b. MAUREENc. BAR d. BABE

4. Of the case study sites discussed, which facility has achievedenergy self-sufficiency?a. Sjolundab. Strassc. Robert W. Hited. 26th Ward

5. The seeding of a mainstream process with ammoniaoxidizing/nitrite oxidizing bacteria grown in a sidestreamreactor is calleda. fermentation.b. bioaugmentation.c. aerobic biosupplementation.d. anaerobic biosupplementation.

Separate or Combined Sidestream Treatment: That Is the Question

Rod Reardon(Article 2: CEU = 0.1 WW}

___________________________________________SUBSCRIBER NAME (please print)

Article 1 ________________________________________LICENSE NUMBER for Which CEUs Should Be Awarded

Article 2 ________________________________________LICENSE NUMBER for Which CEUs Should Be Awarded

If paying by credit card, fax to (561) 625-4858

providing the following information:

___________________________________________(Credit Card Number)

___________________________________________(Expiration Date)

1. Real-time ultraviolet light transmittance data obtained from a2010 South Cross Bayou Water Reclamation Facility(SCBWRF) test yielded a recommended ____ UVT254 designcriteria.a. 55 percent b. 51 percentc. 10 mJ/cm2 d. 100 mJ/cm2

2. After extensive review, which type of ultraviolet (UV) lamparray was selected for this application?a. Vertical b. Horizontalc. Circumferential d. Diagonal

3. The Florida Department of Environmental Protection (FDEP)consent order governing this facility’s discharge to landapplication systems limits dichlorobromomethane toa. 80 micrograms per liter.b. 34 micrograms per liter.c. 20 micrograms per liter.d. This compound is not limited.

4. Two of the three evaluated UV systems used _______ typelamps.a. mercury vapor b. sodium vaporc. high output amalgam d. laser

5. In order to stay below 80 percdent of the annual averagedisinfection byproduct permit limits, a UV treatment capacityof ____ mgd is required for seasonal treatment at this facility.a. 10 b. 13c. 15 d. 20

Incorporation of High-Level Ultraviolet Disinfection to Meet Stringent Effluent

Discharge Disinfection Byproducts Limits

Lynn Spivey, Sean Chapparro, Steve Schaefer, and William Harrington

(Article 1: CEU = 0.1 WW)



Executive CommitteeCarl R. Larrabee Jr., P.E.ChairSt. Johns River Water Management DistrictP.O. Box 1429Palatka, Florida 32178P: (386) 329-4222E: [email protected]

Jason P.F. Parrillo, P.E.Past ChairHydra Service Inc.111 Maritime DriveSanford, Florida 32771P: (407) 330-3456F: (407) 330-3404E: [email protected]

Mark D. LehighChair-ElectHillsborough County Water Resource Services332 N. Falkenburg RoadTampa, Florida 33619P: (813) 272-5977, ext. 43270F: (813) 635-8152E: [email protected]

Kimberly A. KunihiroVice ChairOrange County Utilities9124 Curry Ford RoadOrlando, Florida 32825P: (407) 254-9555F: (407) 254-9558E: [email protected]

William G. YoungSecretarySt. Johns County Utilities1205 State Road 16St. Augustine, Florida 32084P: (904) 209-2703F: (904) 209-2702E: [email protected]

Grace M. Johns, Ph.D.TreasurerHazen and Sawyer P.C.4000 Hollywood Blvd., Suite 750N Hollywood, Florida 33021P: (954) 987-0066F: (954) 987-2949E: [email protected]

Matt Alvarez, P.E.Outgoing General Policy Director (June 2014)CH2M HILL Inc.201 Alhambra Circle, Suite 600Coral Gables, Florida 33134P: (305) 443-6401F: (305) 443-8856E: [email protected]

Jeffrey W. Nash, P.E.Outgoing Association Director (June 2014)CDM Smith2301 Maitland Center Parkway, Suite 300Maitland, Florida 32751P: (407) 718-9956E: [email protected]

Jacqueline W. Torbert Incoming Association Director (June 2014)Orange County Utilities Water Division9150 Curry Ford Road, 3rd FloorOrlando, Florida 32825P: (407) 254-9850F: (407) 254-9848E: [email protected]

Matt Alvarez, P.E.Alternate Association Director (June 2014)CH2M HILL Inc.201 Alhambra Circle, Suite 600Coral Gables, Florida 33134P: (305) 443-6401F: (305) 443-8856E: [email protected]

Ana Maria Gonzalez, P.E.Incoming General Policy Director (June 2014)Hazen and Sawyer P.C.4000 Hollywood Blvd., Suite 750N Hollywood, Florida 33021P: (954) 987-0066F: (954) 987-2949E: [email protected]

Kim KowalskiTreasurer-ElectWager Company of Florida Inc.1611 Silk Tree CircleSanford, Florida 32773P: (407) 834-4667F: (407) 831-0091E: [email protected]

TrusteesFred BloetscherTrusteeFlorida Atlantic UniversityP.O. Box 221890Hollywood, Florida 33022-1890P: (239) 250-2423F: (954) 925-2692E: [email protected]

Christine S. EllenbergerTrusteeJacobs Engineering245 Riverside Avenue, Suite 300Jacksonville, Florida 32202P: (904) 636-5432, ext. 127F: (904) 636-5433E: [email protected]

Mark KellyTrusteeGarney Construction370 E Crown Point RoadWinter Garden, Florida 34787P: (321) 221-2833F: (407) 287-8777E: [email protected]

Dave SlonenaTrusteePinellas County Utilities14 S. Ft. Harrison AvenueClearwater, Florida 33756P: (727) 464-4441 F: (727) 464-3595 E: [email protected]

Tyler TedcastleTrusteeCDM Smith8381 Dix Ellis Trail, Suite 400Jacksonville, Florida 32256P: (904) 527-6721F: (904) 519-7090E: [email protected]

Council Chairs Christopher JarrettAdministrative Council ChairAmerican Cast Iron Pipe Company300 Primera Blvd., Suite 240Lake Mary, Florida 32746-2144P: (407) 804-1420F: (407) 804-1201E: [email protected]

Richard HewittContractors Council ChairPCL Construction Inc.3810 Northdale Blvd., Suite 200Tampa, Florida 33624-1873P: (813) 264-9500F: (813) 961-1576E: [email protected]

2013-2014 FSAWWA BOARD OF GOVERNORS

FloridaSectionAWWA

By Region


Todd LewisManufacturers/Associates Council ChairU.S. Pipe & Foundry LLC 14580 Saint Georges Hill Drive Orlando, FL 32828 P: (407) 592-1175F: (877) 505-1570E: [email protected]

Steve SoltauOperators Council ChairPinellas County Dept. of Environment & Infrastructure3655 Keller CircleTarpon Springs, Florida 34688-7813P: (727) 453-6990F: (727) 453-6962E: [email protected]

Jennifer McElroy Public Affairs Council ChairGainesville Regional UtilitiesP.O. Box 147117 Station A-136 Gainesville, Florida 32614P: (352) 393-1291F: (352) 334-2752E: [email protected]

Roberto DenisTechnical & Education Council ChairLiquid Solutions Group LLC369 Whitcomb DriveGeneva, Florida 32732P: (407) 349-3900F: (407) 349-3935E: [email protected]

Patrick LehmanUtility Council ChairPeace River Manasota Regional Water Supply Authority9415 Town Center ParkwayLakewood Ranch, Florida 34202P: (941) 316-1776F: (941) 316-1772E: [email protected]

Region Chairs Edward A. Bettinger, RS, MSRegion I Chair (North Central Florida)DOH – Bureau of Water Programs4052 Bald Cypress Way, Bin C-22Tallahassee, Florida 32399P: (850) 245-4240 ext. 2696F: (850) 921-0298E: [email protected]

Andrew MayRegion II Chair (Northeast Florida)JEA21 W. Church StreetJacksonville, Florida 32202-3158P: (904) 665-4510F: (904) 665-8099E: [email protected]

Greg Taylor, P.E.Region III Chair (Central Florida)CDM Smith2301 Maitland Center Parkway, Suite 300Maitland, Florida 32751P: (407) 660-2552, ext. 6329F: (407) 875-1161E: [email protected]

Emilie MooreRegion IV Chair (West Central Florida)Tetra Tech400 N. Ashley Avenue, Suite 2600Tampa, Florida 33602P: (727) 709-1705 F: (813) 282-7893E: [email protected]

Ronald CavalieriRegion V Chair (Southwest Florida)AECOM4415 Metro Parkway, Suite 404Fort Myers, Florida 33916-9402P: (239) 278-7996F: (239) 278-0913E: [email protected]

Mike Bailey, P.E.Region VI Chair (Southeast Florida)Cooper City Utilities11791 SW 49th StreetCooper City, Florida 33330-4447P: (954) 434-5519F: (954) 680-3159E: [email protected]

Juan AceitunoRegion VII Chair (South Florida)CH2M HILL Inc.201 Alhambra Circle, Suite 600Coral Gables, Florida 33134P: (305) 443-6401F: (305) 443-8856E: [email protected]

Brad MacekRegion VIII Chair (East Central Florida)City of Port St. Lucie6001 Silver Oak DriveFort Pierce, Florida 34982-3225P: (772) 461-0263F: (772) 461-6405E: [email protected]

Monica AutreyRegion IX Chair (West Florida Panhandle)Destin Water Users Inc.P.O. Box 308Destin Florida 32540-0308P: (850) 837-6146F: (850) 837-0465E: [email protected]

Richard AndersonInterim Region X Chair (West Central Florida)Peace River Manasota Regional Water Supply Authority8998 S.W. CR 769Arcadia, Florida 34269P: (863) 993-4565E: [email protected]

Kristen Sealey Region XI Chair (North Florida)Golder Associates Inc.6026 N.W. 1st Place Gainesville, Florida 32607P: (352) 336-5600F: (352) 336-6603E: [email protected]

Donald E. HammRegion XII Chair (Central Florida Panhandle)Bay County Utility Services3410 Transmitter Road Panama City, Florida 32404P: (850) 747-5703F: (850) 872-4805E: [email protected]

Section StaffPeggy GuingonaExecutive DirectorFlorida Section AWWA1300 Ninth Street, B-124Saint Cloud, Florida 34769P: (407) 957-8449F: (407) 957-8415E: [email protected]

Casey CumiskeyMembership Specialist/Training CoordinatorFlorida Section AWWA1300 Ninth Street, B-124Saint Cloud, Florida 34769P: (407) 957-8447F: (407) 957-8415E: [email protected]

Donna MetherallTraining CoordinatorFlorida Section AWWA1300 Ninth Street, B-124Saint Cloud, Florida 34769P: (407) 957-8443F: (407) 957-8415E: [email protected]

Jenny ArguelloStaff AssistantFlorida Section AWWA1300 Ninth Street, B-124Saint Cloud, Florida 34769P: (407) 957-8448F: (407) 957-8415E: [email protected]


In 2010, municipal wastewater treatment fa-cilities consumed about 25 bil kWh of elec-tricity. Individual facilities use anywhere

from 1,000 to 4,000 kWh per mil gal (MG)treated, depending on the level of treatmentand the overall efficiency of power use. Thisrepresents about 1.5 percent of the total powerdemand in the United States. About half of thepower demand at a wastewater treatment facil-ity is for aeration (10–20 kWh/populationequivalent [p.e.]/yr). Further, nitrification con-stitutes about half the power required for aer-ation, with the actual fraction depending onthe chemical oxygen demand/total Kjeldahl ni-trogen (COD/TKN) ratio in the influent to theaeration tank. Thus, the need for nitrificationconsumes roughly 6 bil kWh per year. While upto 60 percent of this incremental demand canbe offset by incorporating a high degree of den-itrification into the treatment process, the re-mainder still represents a huge power demand.Implementation of new techniques for reduc-ing the power requirement for nitrogen re-moval could significantly lower powerdemands at municipal wastewater treatmentfacilities.

While implementation of nitrogen re-moval at municipal wastewater treatmentplants provides significant public health andenvironmental benefits, nitrogen removalprocesses also require more electrical power tooperate and release more greenhouse gasesthan a comparable secondary treatmentprocess. A standard Modified Ludzack-Ettinger(MLE) process in Florida using an oxidationditch with aerobic holding or digestion of thewaste sludge will consume about 3,000 kWhper mg of water recovered and release over 4.7lbs of CO2 per lb of nitrogen removed. By im-plementing more efficient aeration and anaer-obic digestion, the power demand for this sameMLE process can be reduced about 10 to 20percent, not counting the energy that can berecovered from the biogas generated in the di-gestion process. Despite the attractiveness ofanaerobic digestion from an energy perspec-tive, the destruction of volatile solids during di-gestion releases significant amounts ofnitrogen, which is typically recycled into themainstream treatment process. This recycleload increases the process air, alkalinity, andcarbon requirements for nitrogen removal in

proportion to the mass of ammonia recycled.The magnitude of nitrogen recycle loads

from anaerobic digestion depends on the useof primary treatment, the importing of sludgefrom other facilities, the type of sludge stabi-lization employed, and the degree of volatilesolids destruction achieved. Depending on theplant configuration and dewatering schedule,recycling of sidestream ammonia can result indiurnal spikes in effluent ammonia or total ni-trogen (TN). Using a typical Florida waste-water treatment plant with conventionalnitrogen removal and mesophilic anaerobic di-gestion as an example, ammonia recycle willtypically be between 10 and 15 percent of theinfluent nitrogen load. However, with the ad-dition of sludge from other facilities and theuse of advanced digestion processes, the recycleload can approach 50 percent of the influent.

Overview of Nitrogen Cycle

Significant developments have occurredover the last ten to fifteen years that have im-proved the understanding of the nitrogen cycleand opened new opportunities for managinghigh ammonia sidestreams. One of the mostsignificant advancements in the understandingof the biology of nitrogen transformations isthe discovery of a group of microorganisms inthe phylum Planctomycetes; these have becomebetter known as anammox bacteria (Anaero-bic Ammonia Oxidation). Anammox bacteriaare autotrophic organisms capable of convert-ing a mixture of ammonia and nitrite directlyto nitrogen gas.

It is now recognized that previouslyknown organisms can transform nitrogen bymultiple metabolic pathways, more microor-ganisms are significantly involved in nitrogentransformations, and the interactions amonggroups of bacteria are more complex. The fol-lowing is a brief summary of the three mainapproaches to using conventional and innova-tive biology for nitrification and denitrificationof sidestreams:1. Conventional Nitrification and Denitrifica-

tion – Conventional biological nitrogen re-moval is a multistep process in which acombination of autotrophic and het-erotrophic bacteria sequentially convertsammonia to nitrogen gas according to the

following equations: a. Ammonia is oxidized to nitrite (NO2

-) byammonia oxidizing bacteria (AOBs): NH4

+ + 1.5 O2 → NO2- + H2O + 2 H+

b. Nitrite is converted to nitrate by nitriteoxidizing bacteria (NOBs): NO2

− + 0.5 O2 → NO3−

c. Nitrate is converted to nitrogen gas by or-dinary heterotrophic bacteria (OHOs)6NO3

− + 5CH3OH→ 3N2 + 5 CO2 + 7H2O+ 6OH−

According to these equations for conven-tional biological nitrogen removal processes,the need to remove ammonia affects oxygendemand and alkalinity. In addition, the rela-tively slow growth rate of nitrifiers AOBs andNOBs increases the required sludge inven-tory, but has relatively little effect on sludgeproduction, aside from the decreased yieldassociated with longer sludge retention time(SRT). Denitrification imposes additionalrequirements on biological nutrient removal(BNR) processes, including the need to con-trol dissolved oxygen (DO) input, and foradditional anoxic sludge inventory and suf-ficient carbon relative to the nitrogen to bereduced.

The stoichiometric oxygen requirementfor conventional nitrification is 1.5·32/14=3.43 mg O2/mg N for ammonia oxidationand 0.5·32/14 = 1.14 mg O2/mg N for nitriteoxidation. The first reaction consumes alka-linity. The required COD:N ratio for deni-trification is 2.86. Including sludgeproduction, the required COD:N ratio isabout 4, depending on the carbon source.

2. Shortcut Nitrification and Denitrification –Researchers at the Technical University ofDelft discovered that the conventional nitri-fication process could be stopped halfway;that is, after the formation of nitrite. Theygave this first application of partial nitrifica-tion (or nitritation) the name Sharon (Singlereactor system for High Ammonium Re-

Separate or Combined Sidestream Treatment:That is the Question

Rod Reardon

Rod Reardon is wastewater processengineer with Carollo Engineers inOrlando.

F W R J


FWPCOA TRAINING CALENDARSCHEDULE YOUR CLASS TODAY!

* Backflow recertification is also available the last day of BackflowTester or Backflow Repair Classes with the exception of Deltona

** Evening classes

*** any retest given also

JANUARY 7........Backflow Recert ..........................................Lady Lake ............$85/115

13-16........Backflow Tester ..........................................Deltona ................$375/40513-16........Backflow Tester ..........................................St. Petersburg ......$375/405

24........Backflow Tester Recert*** ........................Deltona ................$85/11527-31........Wastewater Collection C, B ......................Deltona ................$325/35527-31........Wastewater Collection A ..........................Orlando ..............$225/255

FEBRUARY3-7........Water Distribution Level 3, 2 ..................Deltona ................$275/305

10-12........Backflow Repair ........................................Deltona ................$275/30528........Backflow Tester Recert*** ........................Deltona ................$85/115

MARCH4........Backflow Recert ..........................................Lady Lake ............$85/115

3-6........Backflow Tester ..........................................St. Petersburg ......$375/40524-28........SPRING STATE SHORT SCHOOLSPRING STATE SHORT SCHOOL ............Ft. Pierce

28........Backflow Tester Recert*** ........................Deltona ................$85/115

APRIL7-9........Backflow Repair ........................................St. Petersburg ......$275/305

21-24........Backflow Tester ..........................................Deltona ................$375/40525........Backflow Tester Recert*** ........................Deltona ................$85/115

MAY6........Backflow Recert ..........................................Lady Lake ............$85/115

5-9........Wastewater Collection C, B ......................Deltona ................$325/35512-15........Backflow Tester ..........................................St. Petersburg ......$375/40519-21........Backflow Repair ........................................Deltona ................$275/305

23........Backflow Tester Recert*** ........................Deltona ................$85/115

You are required to have your

own calculator at state short schools

and most other courses.

Course registration forms are available at http://www.fwpcoa.org/forms.asp. For additional information on these courses or other training programs offered by the FWPCOA, please

contact the FW&PCOA Training Office at (321) 383-9690 or [email protected].



moval Over Nitrite). Stopping the nitrifica-tion reaction at a nitrite endpoint has alsobecome known as shortcut nitrification den-itrification (or shortcut NDN) since it by-passes or shortcuts the creation of nitrate.The comparable equations for shortcutNDN are as follows:d. Nitritation:

NH4+ + 1.5 O2 → NO2

− + 2 H2O + 2 H+

e. Denitritation: NO2

− + 0.5 CH3OH−→ 0.5 N2 + 0.5 CO2 +0.5 H2O + OH−

The COD:N ratio is 1.72 for denitritation.Including sludge production, the requiredCOD:N ratio is 2.4 (Mulder et al., 2006), de-pending on the carbon source, as comparedto about 4 for conventional denitrification.Oxygen demand is reduced 25 percent andcarbon demand is reduced 40 percent withshortcut NDN as compared to the conven-tional approach.

3. Partial Nitritation and Anammox – Sinceanammox bacteria require about a 50:50 mixof ammonia and nitrite, it is necessary to donitritation in combination with anammox.Only about one-half of the ammonia needsto be converted to nitrite to create the rightmix of feed.f. Nitritation:

NH4+ + 1.5 O2 → NO2

− + 2 H2O + 2 H+

g. Anammox:NH4

+ + NO2− → N2 + 2 H2O

h. Combined Sharon - AnammoxNH4

++ 0.75 O2 +HCO3– → 0.5 NH4+ + 0.5

NO2− + CO2+ 1.5 H2O

The anammox reaction is autotrophic and

has low biomass yield (0.11-0.13 g VSS/gNH4

+-N), but produces small amounts ofNO3

- (according to the molar ratioNO3/NH4

+ = 0.26). Overall nitrogen re-moval in the combined (partial nitritation-anammox) process requires less oxygen (1.9kg O2/kg N instead of 4.6 kg O2/kg N), hasno carbon source (instead of 2.4 – 4 kgCOD/kg N), has low sludge production (0.08instead of approximately 1 kg VSS/kg N),and reduces CO2 emission by more than 100percent because the combined process usesless power and consumes CO2.

Oxygen requirements, carbon demands,and alkalinity requirements resulting fromuse of these main groups of biologicalprocesses are summarized in Table 1.

Separate Methods of Sidestream Treatment

A variety of treatment processes have beendeveloped using both conventional and inno-vative biological concepts to treat high ammo-nia recycle streams. These sidestream treatmentprocesses can be grouped according to the feedstreams sent to the sidestream reactor. Onegroup of processes keeps the sidestream sepa-rate and treats the sidestream by itself. Theother group combines all or a portion of thereturn activated sludge (RAS) with the side-stream. Mixing RAS and the sidestream allowsthe use of some biological reactions (conven-tional, shortcut NDN, and bioaugmentation)and precludes others (anammox at this time).

All but one of the separate methods relieson some sort of biomass retention to developsufficient biomass for treatment. The exceptionis the Sharon process, which uses one or two

completely mixed stirred tank reactors withoutrecycle (chemostats). By operating at a low hy-draulic retention time (HRT), elevated tem-perature, and high ammonia concentrationthat results in the washout of NOBs, theSharon process operates to a nitrite endpoint.With the Sharon process, the nitrites are typi-cally removed by denitrification withmethanol. Anammox bacteria grow muchslower than nitrifiers, and their natural ten-dency to form relatively large granules withslightly greater density compared to normal ac-tivated sludge provides the basis for retainingthese bacteria in the treatment process.

Most separate sidestream treatmentprocesses are well suited for using partial nitri-tation—anammox. However, two of the sepa-rate sidestream processes, short solids retentiontime (SRT) and Sharon, are not applicable forpartial nitritation–anammox. The short SRTprocess, also known as InNitri™, is a side-stream-nitrifying activated sludge process withan aeration tank and clarifier, where wastesludge from the sidestream process is used toseed the mainstream process. There are no full-scale applications of the InNitri™ process.

Understanding of the characteristics ofanammox bacteria and the development ofmethods for using them for nitrogen removalhas evolved over time through research doneby numerous groups. Unfortunately, this hasresulted in a large number of names andpatents for essentially the same biology imple-mented in different reactor configurations withdifferent control methods. A glossary of termsassociated with sidestream treatment is pro-vided at the end of this article.

Current commercially available anammoxsystems for sidestream treatment include twosequencing batch reactor (SBR) processes, anupflow granular bed process, and a moving bedbiofilm reactor (MBBR) process. Dependingon the specific process, biomass retention isprovided by gravity settling, cyclones, granularsludge, or a fixed film on MBBR media. TheSBR processes use pH and DO control tomaintain environmental conditions for theanammox bacteria. The MBBR process relieson the biofilm and control of the DO at lowconcentrations to wash the NOBs out of theprocess. Unlike the SBR/cyclone process, theMBBR process measures NH4, NO2, and NO3,and then uses the ratios of NO2/NH4 andNO3/NH4 to control aeration. Media fills aretypically up to about 50 percent. The longstartup times required for the first anammoxprocesses are now avoided by seeding the reac-tors from other operating systems. The designvolumetric loading rate for the MBBR processis about 1 kg N/m3/d. The granular sludgeprocess can be loaded more heavily, up to


Table 1. Comparison of Biological Processes for Nitrogen Removal (from Jetten et al., 2002 & Ahn, 2006)


about 2 kg N/m3/d, but is reported to be lessstable at the higher loading rates. Anammox re-actions are inherently limited to a maximumammonia removal of about 90 percent; how-ever, they are capable of operating consistentlyat close to this limit.

The advantages of the separate sidestreammethods include the ability to use shortcutNDN and anammox bacteria, and to take ad-vantage of the warm temperature and high am-monia concentration to operate at highbiological reaction rates. Since the effluent istypically recycled to the mainstream process,higher ammonia concentration reactor effluentis acceptable and enables higher reaction rates.

The main advantages to the separate side-stream treatment process using anammox aretheir low energy requirement and their abilityto denitrify without carbon. Without the addi-tion of an external carbon source, sludge pro-duction is lower. As mentioned, the reactorconfigurations vary, but all use proven rectordesigns. The main disadvantages of anammoxprocesses are the slow growth rate of anammoxbacteria, and the need to inhibit or wash NOBsout of the process. The slow growth rate ofanammox bacteria requires seeding for rea-sonably quick startups, but there are nowenough of the systems in existence so that ob-taining seed sludge is feasible.

As a result of the need to prevent thegrowth of NOBs, and to limit the buildup ofnitrite concentrations, the process operatingrequirements are more complex, but the sys-tems are readily automated. While the elevatedtemperatures of sidestreams are conducive tohigher biological reaction rates, the sidestreamreactor temperature must be controlled withinthe range of about 30–40ºC. Depending on thesituation, this may require heating or coolingof the sidestream. Elevated concentrations ofsuspended solids in the sidestream can bedetrimental to the performance of some sepa-rate processes, and possibly require pretreat-ment. Foaming has been reported at severalseparate sidestream treatment facilities, andscaling of the media in one MBBR reactor wasa problem.

Combined Methods of Sidestream Treatment

The combined sidestream processes areknown by many names, including bioaugmen-tation regeneration (BAR); Aeration TankNo.3 (AT-3), named after work at the New YorkCity 26th Ward Water Pollution Control Plant(WPCP); bioaugmentation batch enhanced(BABE); mainstream autotrophic recycle en-abling enhanced N-removal (MAUREEN); andcentrate and RAS reaeration basin (CaRRB).

The common feature to this group of processesis the mixing of a high ammonia sidestreamwith RAS in a sidestream reactor, resulting insubsequent return of the sidestream to themain process. The use of RAS adds alkalinity,lowers temperature, and increases the biomassconcentration in the sidestream reactor.

While conventional microbial processesdo not provide the reduction in oxygen andcarbon demands of shortcut NDN and anam-mox, when used in sidestream reactors theycan provide substantial overall facility benefits.These include:� Bioaugmentation of the mainstream

process with nitrifiers resulting in a reduc-tion in the aerobic SRT needed to maintainnitrification, along with elimination of thesudden washout of nitrifiers that can occurunder wintertime conditions.

� Increased biomass inventory providinggreater overall process stability and reducedeffluent nitrogen, while enabling reducedsolids loading to secondary clarifiers.

� Reduced carbon requirements and im-proved mainstream denitrification if deni-trification is provided in the sidestreamprocess.

� Ability to increase anoxic volume, at the ex-pense of aerobic volume, to increase deni-trification capacity in an existing plant.

� Reduced mixed liquor recycle rates if nitriteor nitrate is returned to a pre-aerationanoxic zone in the mainstream process.

� Potential to inhibit NOBs, thereby combin-ing bioaugmentation with shortcut NDN.

Case Studies

Robert W. Hite Treatment Facility, Denver(CaRRB)

The Metro Wastewater Reclamation Dis-trict (MWRD) in Denver operates the 220-mgd Robert W. Hite Treatment Facility(Facility), which includes two separate primaryand secondary complexes that are served by acommon sludge complex, with mesophilicanaerobic digestion and centrifuge dewatering.In 2004, MWRD began planning improve-ments at the Facility to comply with tighterlimits on ammonia, NOx, and phosphorus.The initial strategy in the north secondarycomplex was based on the addition of two newaeration basins and secondary clarifiers to sup-plement the existing 12 aeration basins andsecondary clarifiers. As an alternative approach,the concept of combined sidestream treatmentwas evaluated and selected for implementation.The concept envisioned the construction ofcommon CaRRBs instead of two new aerationbasins and secondary clarifiers.

Because bioaugmentation reduces the re-

quired SRT for nitrification in the mainstreamprocess, the same nitrification performance canbe maintained at lower bioreactor MLSS con-centrations. This results in lower solids concen-trations entering the secondary clarifiers,subsequently increasing clarification capacity.The original improvements strategy would haverequired two aeration basins with a combinedvolume of 4.1 MG and two 130-ft diameter sec-ondary clarifiers. The CaRRB approach yieldedapproximately 20 percent more capacity thanthe original strategy with the construction ofonly 2.7 MG of centrate reaeration basins andwithout any new secondary clarifiers. This in-creased capacity resulted in a reduction in an-ticipated capital cost of approximately $17million when compared to the original strategy.

Combined sidestream treatment also al-lowed a reduction in the required mixed liquorreturn (MLR) pumping rate. Due to nitrifica-tion of centrate occurring in CaRRB, a signifi-cant amount of nitrate is generated andreturned to the anoxic zones in the mainstreamaeration basins. At MWRD, the CaRRB processgenerates approximately 6,000 to 8,000 ppd ofnitrate as N that is fed to mainstream anoxiczones. This is equivalent to 70 to 100 mgd ofMLR, or a reduction of 6 to 8 mgd per aerationbasin. This allowed installation of smallerpumps and provides an energy cost savings ofapproximately $80,000 per year.

Using combined sidestream treatment af-forded several important advantages over theoriginal improvements strategy, including in-creased capacity and performance at a lowercost, reduction in required mixed liquor returnpumping, and improved denitrification. TheCaRRB process has been in service since August2009 and performance has exceeded expecta-tions and confirmed the benefits offered by thisprocess. Based on this success, CaRRB is beingincorporated into the upgrades to the southsecondary complex now under construction.

26th Ward Water Pollution Control Plant,New York City (Aeration Tank 3)

Starting in 1992, as part of its program toeliminate the ocean disposal of sludge, NewYork City implemented a centralized sludge de-watering scheme where anaerobically digestedsludge from the City’s 14 WPCPs are pumpedor barged to eight centralized dewatering facil-ities. As a result, the nitrogen loads on theWPCPs that host the centralized dewatering fa-cilities are increased by 30-50 percent from theincreased centrate that is returned to the main-stream treatment processes. As centrate wasidentified as a significant source of nitrogen tothe WPCPs, the City undertook investigationsto find a feasible treatment method.



The New York City Department of Envi-ronmental Protection (DEP) investigationsinto centrate treatment began at the City’s 26thWard WPCP, which has a central dewateringfacility that receives sludge from up to fourother WPCPs. This 85-mgd WPCP, located inBrooklyn and discharging to Jamaica Bay, usesa high-rate, four-pass step-feed-activatedsludge process to treat average flows of about70 mgd. Three step-feed tanks, each with a vol-ume of 5 MG, provide aeration. Primary clar-ifier effluent is added to Passes B, C, and D ofthe step-feed aeration tanks, while RAS isadded to Pass A. Anoxic zones are present at thebeginning of Passes A, B, and C. After experi-menting with several configurations, the DEPsettled on a combined sidestream treatmentprocess in which AT-3 was dedicated to cen-trate treatment. All of the centrate (about 1.3mgd) is sent to AT-3, along with about 0.5-1.0mgd of RAS (out of 10-15 mgd). The centrateaverages about 750 mg/L ammonia with a sol-uble COD of 270 mg/L, a temperature of 28ºC,pH values of 8.3-8.5, and an alkalinity of 2,200mg/L as CaCO3. The effluent from AT-3 is re-turned to the RAS channel whereby it entersPass A of the other two aeration tanks.

The AT-3 combined sidestream treatmentprocess has proven to be very effective, and hasprovided significant benefits to the City. Bioaug-mentation of the mainstream, high-rate, step-feed BNR process (2-3 day SRT) at wintertimetemperatures as low as 12ºC, allows stable year-round nitrogen removal with lower effluent TNconcentrations. A calibrated process simulationmodel, based on extensive kinetic testing (Ra-malingam, 2007), predicts that use of the AT-3process is lowering the effluent TN during thewinter from 16 mg/L to 11 mg/L, and modelpredictions are in line with current perform-ance. In addition, the combination of high am-monia concentrations and high pH in thecentrate tank combined with low DO concen-trations in Pass A provides shortcut nitrification(inhibition of NOBs), resulted in a large reduc-tion in process air requirements, and a reduc-tion in carbon requirements in the step-feedBNR, which enhances denitrification. Estimatesare that process airflow has been reduced fromabout 24,000 scfm to 16,000 scfm by using theAT-3 process.

Sjölunda WWTP, Malmo, Sweden(ANITA™ Mox)

The Sjölunda Wastewater Treatment Plantprovides wastewater treatment for Malmo,Sweden’s third largest city, and surroundingareas. With a design capacity of 550,000 p.e.(about 50 mgd), the plant currently treats

about 37 mgd, on average. The plant uses acombination of primary clarifiers with ferroussulfate addition for phosphorus removal, high-rate activated sludge (3-day SRT) with pre-anoxic zones, nitrifying trickling filters, anddenitrifying MBBRs to meet effluent targetconcentrations of 0.3 mg/L total phosphorous(TP), on a monthly average, and 10 mg/L TN(annual average). Sludge treatment is providedby anaerobic digestion with centrifuge dewa-tering. The centrifuges operate about 50 per-cent of the time. When the plant was lastupgraded in 1999 to provide nitrogen removal,an equalization tank and a SBR (0.5 mgal) withNaOH addition were added to remove about1,500 lbs NH4

-N/d from the centrate and lessenthe ammonia load on the nitrifying tricklingfilters. The centrate nitrogen load is approxi-mately 20 percent of the influent nitrogen load.The centrate flow at Sjölunda averages about172,000 gal/day, with a mean ammonia con-centration of 855 mg/L, a mean soluble CODconcentration of 257 mg/L, and a mean totalsuspended solids concentration of 350 mg/L.

Beginning in August 2010, a new MBBR-based, separate sidestream treatment process,named ANITA™Mox, started operation atSjölunda. The new system treats about 30 per-cent of the centrate flow (the design N loadequals 440 lb N/d), while the remainder istreated by the existing SBR. The full-scaleANITA™ Mox plant consists of four13,200-galreactors with three different types of MBBRmedia (one with BiofilmChip M, two with K3,and one with AnoxK5), with media fills of about50 percent. The specific surface areas for thethree types of media are 500 m2/m3, 800 m2/m3,and 1200 m2/m3 respectively. Continuous aera-tion is provided by coarse bubble diffusers. DOis controlled to 0.5–1.5 mg/L. Neither tempera-ture nor pH is controlled with pH, varying from6.7-8.1, while reactor temperatures range from22–33ºC. The system supplier, Veolia, has usedthis facility to demonstrate its BioFarm conceptwhere media, with established anammox bio-mass, is used to seed and startup new facilities.Effluent typically contains about 100 mg/L ofNH4 and NO3, and about 1 mg/L NO2. The de-sign volumetric loading rate for the ANITA™Mox process is about 1 kg N/m3/d and theSjölunda facility has operated successfully atloadings up to 1.25 kg N/m3/d. The ANITA™Mox process consumes about 1.4–1.7 kWh/kgN removed. Studies on N2O generation in theMBBR and the SBR process suggest that theMBBR produces less N2O—about 0.75 percentof the TN removed versus about 4.1 percent ofthe TN removed for the SBR process.

In summary, the new, separate sidestreamtreatment process removes nitrogen, whileusing less power without carbon addition, pH,

or temperature control and producing less N2Othan the parallel SBR process, which only pro-vides nitrification.

Strass Wastewater TreatmentPlant, Strass im Zillertal, Austria

(Demon)

The Achental-Inntal-Zillertal WastewaterBoard owns and operates the Strass WastewaterTreatment Plant located in Strass im Zillertal(Tirol) Austria. The Strass plant is noted be-cause it has achieved energy self-sufficiency—producing more power than it consumes. Strassis also where the pH controlled DEamMONifi-cation (Demon) separate sidestream treatmentprocess was developed and first implemented.

The Demon process has been in operationat Strass since 2004, and currently treats about440–550 lb/d of nitrogen with maximum in-fluent loads about 900 lb/d. The distinguishingcharacteristics of the Demon process are 1) pHcontrol, 2) use of cyclones to retain anammoxgranules in the process, and 3) use of a SBR re-actor configuration. No chemicals are added tothe Demon process. The Demon is operated asan SBR with four cycles per day. The process iscontrolled within a very narrow pH bandaround 7.1. When the pH exceeds 7.1, the air isturned on, and when the pH drops below pH7.09, the air is turned off.

The Strass plant was commissioned in1989 to provide wastewater service to the pop-ulation of three valleys in Austria: the Achental,the Inntal, and the Zillertal. The plant dis-charges to the Isar River, one of the main trib-utaries of the Danube. The current ammonialimit is ≤ 5 mg N/L, and ≤ 10 mg/L during peakflows. Typical effluent nitrogen concentrationsare 4 mg/L NH3, 5-12 mg/L NO3, and 2 mg/LNO2. The plant achieves 50-60 percent removalof TN in winter, and 80-90 percent removal ofTN in the summer. The plant adds sodium alu-minate to remove phosphorus. Effluent totalphosphorus (TP) concentrations are typicallyabout 0.5 mg/L.

The treatment plant uses an A-B processas the mainstream treatment process. The Astage has a hydraulic retention time of about15-20 minutes and a SRT of about 0.5 days.The A stage provides about 50 percent removalof BOD5, and no more than 10-15 percent re-moval of TKN. Two A-stage aeration tankswere constructed; however, the plant only usesone. The B stage uses a MLE-type process im-plemented in an oxidation ditch configurationconsisting of four rectangular looped reactors,with each pair operating with anoxic and aer-obic zones. There is mixed liquor recycle usingsubmersible pumps with a maximum capacityof about 100 percent of design flow.


The plant has two egg-shaped digesters,and is able to produce about 1.8 ft3 of biogasper p.e. per day. The waste sludge from the Aand B stages; internal grease; external fats, oils,and grease (FOG); and external food waste aremixed and then fed to the anaerobic digesters.It is estimated that the plant receives about3,300 yd3/year in food waste, and about 1,300yd3/year in grease. The digesters operate withan HRT of about 40 days in summer, but only15 days in winter due to the high tourist loads.The digested sludge is thickened and then de-watered with a plate and frame press to a solidsconcentration of about 30 percent.

The Demon process was implemented inthe second, unused A-stage aeration tank. Theammonia concentration in the Demon feed (fil-trate) varies seasonally between 1,600–2,000mg/L. Filtrate COD concentration varies be-tween 500–1,500 mg/L. Typical effluent from theDemon process consists of 10–100 mg/L NH3

-

N, 30–100 mg/L NO3-N, <2 mg/L NO2

-N, and300 mg/L COD, with a maximum of 500 mg/L.Operating the Demon process at the Strass plantrequires 0.5–1.0 hours per day of labor.

In 2010, the plant generated about 10,900kWh/d from biogas, which is about 160 per-cent of the power required to run the plant.Implementation of the Demon process at theStrass plant reduced overall plant power de-mand by about 8.5 to 12 percent. Overall en-ergy demand at the Strass plant, per unit massof nitrogen removed, has decreased over time:� 6 kWh/kg N when operated as a conven-

tional nitrification/denitrification process.� ~3 kWh/kg N with sidestream nitrogen re-

moval provided by nitritation-denitritation.� 1.2 kWh/kg N with the current Demon

process (nitritation/anammox).

Summary

General guidelines have been published(van Loosdrecht, 2006) on factors to considerwhen evaluating the potential for implement-ing sidestream treatment. Depending on site-specific conditions, in particular, the limitingaspects of the treatment process, either a sepa-rate or a combined process may be most bene-ficial. When nitrification or denitrification islimiting in the mainstream process, combinedtreatment (bioaugmentation) may provide themost benefit, as was demonstrated at both theFacility in Denver and the 26th Ward WPCP inNew York. Separate treatment would be indi-cated if mainstream aeration capacity or car-bon is limiting, or to reduce air or energy use,as was demonstrated at the Strass plant.

Whether separate or combined sidestreamtreatment is best is a question that cannot be



answered in general, but must be answered forindividual facilities. A variety of separate andcombined sidestream treatment technologieshave been developed and successfully imple-mented at full-scale municipal wastewatertreatment plants. When appropriate circum-stances exist, they offer a strong set of tools forreducing the cost of treatment and optimizingnitrogen removal in BNR processes.

A Glossary of Terms for Sidestream Treatment

(some appear in the article)

AOBs ammonia oxidizing bacteriaAOA ammonia oxidizing archaeaAnammox anaerobic ammonium

oxidation; oxidation ofammonium to nitrogen gasunder anoxic conditions withnitrite as the electronacceptor; also a single-stagenitritation-anammox processusing granular sludge.

bioaugmentation seeding of a mainstreamprocess with AOBs/NOBsgrown in a sidestreamreactor; also known as AT-3,BABE, BAR, CaRRB, andMAUREEN

deammonification aerobic/anoxic process forautotrophic nitrogenremoval where about one-half of the NH4 is oxidized toNO2 and the remainder ofthe ammonia is convertedtogether with the NO2 tonitrogen gas; also known asDEMON, CANON, OLAND,SNAP, and DIB

denitrification anoxic process in whichnitrite and nitrate arereduced to gaseousnitrogen oxides (nitric oxide(NO), nitrous oxide (N2O)and free nitrogen (N2)

denitritation reduction of nitrite tonitrogen gas

nitrification aerobic, sequentialoxidation of ammonia tonitrite, and nitrite to nitrate

nitritation aerobic oxidation ofammonia to nitrite; alsoknown as SHARON orshortcut nitrification

NOBs nitrite oxidizing bacteria

Combined (Bioaugmentation) ProcessesAT-3 sidestream treatment

process; named after NYC

26th Ward WPCPBABE bioaugmentation batch

enhanced processBAR bioaugmentation

regeneration processCaRRB centrate and RAS reaeration

processMAUREEN mainstream autotrophic

recycle enabling enhancedN-removal

Separate (Shortcut Nitrification) ProcessesSharon single reactor for high

ammonia removal over nitrite

Separate (Nitritation-Anammox) ProcessesAnammox™ nitritation-anammox

process using a single-stage granular sludgebioreactor

ANITA™ Mox nitritation-anammoxprocess using a single-stage MBBR bioreactor

CANON complete autotrophicnitrogen removal over nitrite

DIB deammonification ininterval-aerated biofilmsystem

DeAmmon a nitritation-anammoxprocess using a single-stage MBBR bioreactor

DEMON pH controlledDEamMONification

OLAND oxygen-limited autotrophicnitrification-denitrification

SNAP single-stage nitrogenremoval using the anammoxand partial nitritation

References

• Ahn, Y.-H. (2006) Sustainable NitrogenElimination Biotechnologies: A Review.Process Biochem., 41, 1709-1721.

• Gustavsson, D. J. I. (2010) Biological SludgeLiquor Treatment at Municipal WastewaterTreatment Plants - A Review. VATTEN, 66,179-192.

• Hellinga, C.; Schellen, A. A. J. C.; Mulder, J.W.; van Loosdrecht, M. C. M.; Heijnen, J. J.(1998) The Sharon Process: An InnovativeMethod for Nitrogen Removal from Ammo-nium-Rich Waste Water. Water Sci. Technol.,37 (9), 135-142.

• Henze, M.; van Loosdrecht, M. C. M.; Ekama,G. A.; Brdjanovic, D. (2008) Biological Waste-water Treatment: Principles, Modeling, andDesign. IWA Publishing, London, UK.

• Katehis, D.; Stinson, B.; Anderson, J.;Gopalakrishnan, K.; Carrio, L.; A., P. (2002)Enhancement of Nitrogen Removal thru In-

novative Integration of Centrate treatment.Proceedings of the 75th Annual Water Envi-ronment Federation Technical Exhibition andConference; Chicago, IL, Sept. 29 – Oct. 2;Water Environment Federation: Alexandria,VA.

• Kos, P. (1998) Short SRT (Solids RetentionTime) Nitrification Process/Flowsheet. WaterSci. Technol., 38 (1), 23-29.

• Leu, S.-Y.; Stenstrom, M. K. (2010) Bioaug-mentation to Improve Nitrification in Acti-vated Sludge Treatment. Water Environ. Res.,82, 524-535.

• Luna, B.; Narayanan, B.; Rogowski, S.;Walker, S. (2010) Metro's CaRRB Diet - Cen-trate Treatment Process Tackles Big Chal-lenges in a Small Package. Proceedings of the83rd Annual Water Environment FederationTechnical Exhibition and Conference; New Or-leans, Oct. 2 – 6; Water Environment Feder-ation: Alexandria, VA.

• Mulder, J. W.; Duin, J. O. J., Goverde, J.;Poiesz, W. G.; van Veldhuizen, H.M.; vanKempen, R.; Roeleveld, P. (2006) Full-scaleexperience with the Sharon process throughthe eyes of the operators. Proceedings of the79th Annual Water Environment FederationTechnical Exhibition and Conference; Dallas,TX, Oct. 21 – 25; Water Environment Feder-ation: Alexandria, VA.

• Parker, D.; Wanner, J. (2007) Review of Meth-ods for Improving Nitrification throughBioaugmentation. Water Practice, 1, 1-16.

• Ramalingam, K.; Thomatos, S.; Fillos, J.;Dimitrios, K.; Deur, A.; Navvas, P.; Pawar, A.(2007) Bench and Full Scale Evaluation of anAlternative Sidestream BioaugmentationProcess. Proceedings of the 83rd Annual WaterEnvironment Federation Technical Exhibitionand Conference; San Diego, Oct. 13 – 17;Water Environment Federation: Alexandria,VA.

• van der Star, W. R.; Abma, W. R.; Blommers,D.; Mulder, J. W.; Tokutomi, T.; Strous, M.;Picioreanu, C.; van Loosdrecht, M. C. (2007)Startup of Reactors for Anoxic AmmoniumOxidation: Experiences from the First Full-Scale Anammox Reactor in Rotterdam. WaterRes., 41 (18), 4149-4163.

• van Dongen, L. G. J. M.; Jetten, M. S. M.; vanLoosdrecht, M. C. M. (2001) The CombinedSharon/Anammox Process – A SustainableMethod for N-Removal from Sludge Water.IWA Publishing: London, UK.

• van Loosdrecht, M. C. M.; Salem, S. (2006)Biological Treatment of Sludge Digester Liq-uids. Water Sci. Technol., 53 (12), 11-20.

• Wett, B.; Rostek, R.; Rauch, W.; Ingerle, K.(1998) pH-Controlled Reject Water Treatment.Water Sci. Technol., 137 (2), 165-172. ��




1. Which is a higher life form in the acti-vated sludge process: a free swimmingciliate, a stalked ciliate, or a rotifer?a. Free swimming ciliateb. Stalked ciliatec. Rotiferd. They are all the same.

2. Given the following data, what is thesolids loading rate on the secondary clar-ifiers?• Plant influent flow is 5.5 mgd• The return activated sludge (RAS) rate

is 50 percent of Q• There is one 100-ft diameter second-

ary clarifier• The aeration mixed liquor suspended

solids (MLSS) is 2,200 mg/La. 19.3 lbs/day/ft2

b. 8.6 lbs/day/ft2

c. 18.9 lbs/day/ft2

d. 15.5 lbs/day/ft2

3. What is the best definition of a shockload?a. An unexpected bump.b. A strong influent waste strength.c. A high concentration of total sus-

pended solids (TSS).d. A heavy truck load entering the

plant.

4. Which condition may produce the bestdenitrification efficiency in an aerationtank?a. High air supplyb. High aeration dissolved oxygen (DO)c. Low aeration DOd. Low RAS rate

5. Which zone of a biological nutrient re-moval (BNR) plant produces a release ofphosphorus and is responsible for condi-tioning the phosphorus for later uptakein the downstream zones?a. Anoxicb. Fermentationc. Aerobicd. Reaeration

6. Which group of bacteria is responsiblefor conversion of inorganic ammonia inwastewater?a. Carbon eatersb. Methanogensc. Autotrophicd. Heterotrophic

7. What is the advanced stage of activatedsludge called when bacteria oxidize theirown cell mass?a. Log growthb. Declining growthc. Cathodic protectiond. Endogenous respiration

8. Which group of bacteria can be faculta-tive and are responsible for carbona-ceous biochemical oxygen demand(CBOD5) removal and denitrification inthe activated sludge process?a. Heterotrophicb. Nitrosomonasc. Autotrophicd. Fermenters

9. How much alkalinity is required to con-vert 1.0 lb of ammonia-nitrogen duringthe nitrification process?a. 7.2 lbsb. 8.34 lbsc. 7.48 lbsd. 4.6 lbs

10. Which adjustment will create an in-creased contact time in the aerationtank?a. Lower the weir.b. Increase the air supply rate.c. Decrease the WAS rate. d. Decrease the RAS rate.

Answers on page 78

Readers are welcome to submitquestions or exercises on water or wastewater treatment plantoperations for publication inCertification Boulevard. Send your question (with the answer) or your exercise (with the solution) by email [email protected], or by mail to:

Roy PelletierWastewater Project Consultant

City of Orlando Public Works DepartmentEnvironmental Services

Wastewater Division5100 L.B. McLeod Road

Orlando, FL 32811407-716-2971

Certification Boulevard

Roy Pelletier

SEND US YOURQUEST IONS

Test Your Knowledge ofWastewater Treatment Topics

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ANSWERS? Check the Archives

Are you new to the water andwastewater field? Want to boostyour knowledge about topicsyouʼll face each day as awater/waste-water professional?

All past editions of CertificationBoulevard through the year 2000are available on the Florida WaterEnvironment Associationʼs websiteat www.fwea.org. Click the “SiteMap” button on the home page,then scroll down to the CertificationBoulevard Archives, located belowthe Operations Research Commit-tee.

Doug Prentiss Sr.

Applications for the2013 FWEA safetyawards started com-

ing in early this year, withseveral inquiries received at

the end of the year, which is a good indicatorfor water reclamation workers around ourstate. We have changed the submission re-quirements over the years based on the date ofthe Florida Water Resources Conference,where the awards are given out during theFWEA luncheon.

First-, second-, and third-place plaquesare eligible for Class A, B, C, and D treatmentand reclamation facilities. The FWEA Top Tenprogram also recognizes organizations thatpromote safe operations. Applications can beaccessed at www.fwea.org in the awards sec-tion, or by contacting me at [email protected]. The application can alsobe downloaded from my website atwww.dougprentiss.com. Please note the newsection for emergency response and high-haz-ard workers and teams.

Electronic submittals are not required butare encouraged. Please remember to include a

picture of your facility, along with a brief de-scription of why your organization was award-worthy in 2013. Your picture could end up ina future issue of this magazine.

The final day for sub-mission for any categoriesof the 2013 FWEA safetyawards is Feb. 15, 2014.

Doug Prentiss is pres-ident of DPI, providing awide range of safety services throughout Florida.He also serves as chair of the Florida Water En-vironment Association Safety Committee. ��

2013 FWEA Safety Award

ACCIDENT POTENTIAL RATING (Please check all processes and chemicals used atyour facility.)

� Raw Sewage Pumping � Screening � Grit Removal� Primary Clarifiers � Activated Sludge � Filters� Sludge hauling � Blowers � Pure Oxygen Generation� Mechanical Mixers � Secondary Clarifiers � Sludge drying� Reuse/Effluent Pumping � Post Aeration � Anaerobic Digestion� Aerobic Digestion � Holding Tanks � Sludge Thickening – Gravity� Sludge Thickening Mechanical � Vacuum Filters � Drying Beds� Incineration � Application � Lagoon/Polishing Ponds� Aerated Lagoon � Composting � Lime Stabilization

HAZARDOUS CHEMICALS USED: (State Pounds or Gallons used per day.)

� Chlorine.................................. ________ � SO2.................................. ________� Alum ...................................... ________ � Acid .................................. ________� Methanol ................................ ________ � Lime ................................ ________� Ozone .................................... ________ � Polymer............................ ________� Potassium Permanganate...... ________ � Caustic ............................ ________� Hydrogen Peroxide ................ ________ � Chlorine Compounds ...... ________

Other Chemicals: Identify Type, %, and GPD

1. ____________________________________________________________________

2. ____________________________________________________________________

3. ____________________________________________________________________

4. ____________________________________________________________________

SAFETY TEAMS: Examples: FlaWARN, Confined Space Rescue, Emergency Response,First Responders, Airline/SCBA Entry Teams, or any safety related group designated toperform safety functions for your facility.Please list name and purpose, additional narrative can be attached.

1. ____________________________________________________________________

2. ____________________________________________________________________

3. ____________________________________________________________________

4. ____________________________________________________________________

5. ____________________________________________________________________

Application Deadline: Feb. 15, 2014.Return completed application to: FWEA Safety Committee c/o Doug Prentiss, 13409 NW 202 Street, Alachua, FL 32615

Office/home Phone: (386) 462 3085 • Cell: 352 538 3491 • E-mail: [email protected]

Facility Name: ______________________________

__________________________________________

Facility Mailing Address: ______________________

__________________________________________

__________________________________________

Facility Phone Number: _______________________

Facility Address (if different from mailing address):

__________________________________________

__________________________________________

__________________________________________

Facility Category: (A. B, C, or D) ________

Average Daily Flow (mgd): ________

Number of Employees at Facility: ________

Number of Man-hours Worked at the Facility (January 1 to December 31, 2013): ________

Number of Lost Days for 2013: ________

When was last accident resulting in a fatality? ________

List type of accidents:

1. ________________________________________

2. ________________________________________

3. ________________________________________

On a separate attachment, describe your facility safetyprogram. Be sure to include in your description thenumber of safety training sessions, subjects covered,and length of training in hours during the 2013 calendaryear. Each facility must show actual man-hours spentat that facility and safety training done for that facility.

Electronic submissions may be sent to [email protected]

Please include a digital photo of your operation.

FLORIDA WATER ENVIRONMENT ASSOCIATION2013 SAFETY AWARD APPLICATION

SPOTLIGHT ON SAFETY



As nutrient requirements are tighten-ing in the United States, one of thebiggest challenges in wastewater

treatment has become to reliably meet efflu-ent limits in a sustainable manner. The reli-ability requirement is driven by the need tomeet strict effluent daily or weekly limits setin permits to protect the designated uses ofthe receiving water. Hence, facilities facingmore strict nutrient requirements have toconsider a wide, and possibly confounding,array of treatment technologies. In order toaddress this issue, The U.S. EnvironmentalProtection Agency (EPA) has recently pub-lished a technical document that includesprocess descriptions and operating factorsfor over 40 different treatment technologiesfor removing nitrogen, phosphorus, or both,from municipal wastewater streams ( EPA,2009).

Nutrient removal processes, however,come at a cost to municipal wastewater treat-ment facilities and their ratepayers. Althoughfunding from various sources might be avail-able, they are not generally sufficient to ad-dress all aspects of the necessaryimprovements for nutrient removal. Anotherimportant factor affecting the cost of nutri-ent removal at wastewater facilities is sitelimitations on physical expansion of theirtreatment facilities. Some plants are locatedin urban areas and do not have any way toobtain the physical space necessary to ex-pand. Space limitations can severely limit thetype of processes that can be used to reduce

nutrients (Naik and Strenstrom, 2011).Therefore, the BioMag process is a recentlydeveloped, emerging technology that aims toincrease the capacity of treatment plants andto enhance nutrient removal in facilities thathave limited spaces.

Objectives

The main objective of this article is tointroduce the BioMag process as an alterna-tive to enhance the capacity and effluentquality of existing treatment plants. Objec-tives that are more specific are:� To present the BioMag process and to

provide the advantages and disadvantagesof this emerging technology.

� To investigate nutrient removal capacityof this technology by providing severalexamples from existing pilot scale proj-ects.

� To discuss the design considerations ofthe BioMag process.

� To provide a case study to compare thefootprint of the BioMag process withother alternatives.

BioMag Process

The BioMag process is a ballasted floc-culation-aid wastewater treatment processthat uses magnetite to increase the specificgravity of biological floc. It was developedand patented by Cambridge Water Technol-ogy (CWT) in 2010 (Woodard et al., 2010),

which is currently owned by Siemens. Mag-netite (Fe3O4) is an inert iron ore, with a spe-cific gravity of 5.2 and a strong affinity forbiological solids. In this process, magnetiteintegrates with the biological floc, substan-tially increases the settling rate of the bio-mass, and improves overall solids removal.Figure 1 depicts the magnetite-introducedfloc (right side) and compares it with nor-mal floc. The dark spots appear on the rightimage are magnetite added into the process.

The BioMag process provides the abil-ity to operate the reactors at three to fourtimes above traditional activated sludgeprocess mixed liquor suspended solids(MLSS) concentrations, while still maintain-ing adequate settling and thickening in thesecondary clarifiers. This allows existing ac-tivated sludge systems to treat two to threetimes the original design flows and loadingsat food-to-microorganism ratios (F/M),which are similar to conventional activatedsludge systems, thereby increasing plant ca-pacity within the same footprint. Theprocess also facilitates nitrogen and phos-phorus removal by allowing plants to in-crease the sludge retention time (SRT) andfree up existing aeration tankage for use asanoxic and/or anaerobic zone(s). It providesenhanced and reliable removal of suspendedsolids, nitrogen, and phosphorus.

A schematic diagram of the BioMagprocess is illustrated in Figure 2. Mixedliquor is introduced with both recovered andvirgin magnetite in a continuously mixedtank before entering into activated sludge.Then, mixed liquor, including magnetite, isfed into the reactor where it is held in sus-pension through a combination of aerationand supplemental mechanical mixing. Afterclarifiers, the return activated sludge (RAS)is conveyed from the clarifier to the reactor.Activated sludge is wasted from the RAS lineand sent to a magnetite/waste activated

Getting More Out of Activated Sludge Plants by Using a BioMag Process

Derya Dursun and Jose Jimenez

Derya Dursun, Ph.D., P.E., is processengineer and Jose Jimenez, Ph.D., P.E., isvice president—technology and innovationat Brown and Caldwell in Maitland.

F W R J

Figure 1. Comparison of Flocs With and Without Magnetite Addition (from Andryszak et al., 2011)

sludge (WAS) separation system for removalof the magnetite prior to the sludge process-ing. The magnetite removed from the WASline is recovered and sent into the mixingtank. The magnetite separation and recoveryprocess starts with shear mills that applyhigh-shear forces to break up the floc. It isthen followed by a rotating magnetic drumto separate the magnetite from the WAS.Once separated, the WAS is sent to solidsprocessing facilities.

The BioMag magnetite recovery processhas an efficiency rate of 85 to 95 percent.Makeup magnetite is added to maintain thedesign MLSS-to-magnetite weight ratio of0.8 to 1.5 (optimum 1), depending on theapplication. Approximately 100 lbs ofmakeup magnetite are needed for mil gal(MG) of wastewater treated, based on an ap-proximation of the total sludge yield being 1dry ton/MG of wastewater treated. Averagecost for magnetite has been around $0.25/lb,which would be at $25 of magnetite cost for1 MG wastewater treated.

The main advantage of the BioMagprocess is that it can easily be applied to theconventional activated sludge process in con-fined spaces, with the advantage of eliminat-ing the need of any additional enhancednutrient removal (ENR) reactor and/or clar-ification capacity. It can notably enhance thecapacity of the facility, improve secondaryeffluent quality, and increase the nutrient re-moval capacity of the plant. The BioMagprocess also offers significant capitalcost/benefits compared to traditional bio-logical processes.

On the other hand, there are some dis-advantages of this technology not identifieduntil recently. The process is still in the in-fant phase, where there are some unknowns.The facility that decides to implement thistechnology would need to make some as-sumptions and would involve some risks as-sociated with the technology. Conducting apilot-scale project before implementation ofthe full-scale process would lower the risk;however, the process does not have much es-tablished information like other traditionalprocesses. Other than that, the BioMagprocess is not suited for intermittent opera-tion. The life of shear mills necessary for theseparation of magnetite from biological flocshas been questionable. If the facility does nothave an influent fine screen or primary clar-ifiers, a fine screen should be incorporatedinto the WAS line to protect the shear millfrom becoming clogged or damaged. Theprocess can also be energy intensive due tohigh mixing requirements and the amountof shear necessary to break the flocs in mag-

netite separation step. Major challenges ofthe BioMag process are addressed in theprocess design considerations section.

Nutrient Removal Capability

Due to the fact that the BioMag processis still being developed, there is limited dataavailable on nutrient removal capacity of theprocess. Table 1 provides the list of BioMagprojects.

As indicated in Table 1, almost all Bio-Mag applications aim to enhance nutrientremoval. Although the data from some facil-ities have been published in various confer-ence proceedings, some facilities are in theconstruction or design phase where no dataare available.

The Sturbridge Wastewater TreatmentPlant (WWTP) in Massachusetts has com-pleted successful full-scale demonstrationthat doubled the capacity of the plant’s acti-vated sludge system, resulting in BioMagprocess selection for application. This facilityhas a 1.3-mgd treatment capacity and in-

cludes an ENR upgrade, utilizing existingtankage. After the successful pilot project,construction activities were initiated in Feb-ruary 2010 and the project was completed inthe summer of 2012. There were many chal-lenges in the startup of the project; however,data collected to date clearly show that efflu-ent total nitrogen (TN) and total phospho-rus (TP) values of 3.0 mg/l and 0.05 mg/l areachievable (Catlow & Woodard, 2012).

Another successful full-scale demon-stration was conducted at Upper GwyneddWWTP in Pennsylvania. This facility in-cludes a 3-mgd enhanced nutrient removalupgrade and a 13-mgd wet weather flowtreatment, utilizing existing tankage. This fa-cility had to demonstrate TP < 0.2 mg/lwhile maintaining effluent total suspendedsolids (TSS) < 10 mg/l monthly average,TSS< 30 mg/l during a wet weather event,and effluent cBOD<5 mg/L. The results in-dicated that the facility could meet effluentrequirements by implementing the BioMagprocess.

Table 1. List of BioMag Process Applications

Figure 2. Schematic Diagram of BioMag Process (from Siemens)

Florida Water Resources Journal • January 2014 63Continued on page 64


The Mystic WWTP located in Con-necticut was in need of a process upgrade tomeet future requirements for effluent totalnitrogen. A full-scale demonstration of theBioMag process was completed from Sep-tember 2009 through January 2010 to verifyachievement of required process perform-ance (Moody et al., 2011). Based on the re-sults from the demonstration project, thefacility could meet effluent TN<5 mg/L andeffluent ammonia <1 mg/L. The sludge vol-ume index (SVI) was around 80 mL/g.

A pilot-scale project was conducted atthe Winebrenner WWTP, located in Mary-land. This four-stage Bardenpho facility isrequired to have a 0.6-mgd capacity, with anENR upgrade utilizing existing tankage. Theprocess has to achieve effluent TN <3.0 mg/Land TP < 0.3 mg/L. A full-scale four-monthdemonstration financed by the MarylandDepartment of Environment (MDE) met allsuccess criteria. The BioMag process was op-erated for varying influent loading condi-tions at a MLSS concentration of 10,000mg/L between 6-11°C, achieving TN < 3mg/L, TP < 0.2 mg/L, and TSS < 5 mg/Lwithout the use of effluent filters (Andryszaket al., 2011).

The 1.1-mgd-capacity TaneytownWWTP located in Maryland has two se-quencing batch reactors (SBRs). A full-scaletrial of the BioMag process was conducted in2010, representing its first application to anSBR. The full-scale project demonstrated ef-fluent TN and TP concentrations averaging1.2 mg/L and 0.11 mg/L, respectively. The fa-cility could successfully meet all perform-

ance requirements (TN < 3.0 mg/L and TP< 0.3 mg/L) by adopting the BioMag process(Lubenow et.al., 2011).

Although, BioMag is an emerging tech-nology, it presents promising results for ENRin pilot- and full-scale demonstration proj-ects. Still, application of this technology infull-scale projects is needed to be able to es-tablish the capabilities in nutrient removal.

Process Design Considerations

As indicated previously, there are manyareas that are not clearly identified in thisprocess. The first issue is the conveyance ofsolids, which includes magnetite. The trans-portation of dense solids in RAS and WASlines might require higher energy pump ca-pacity; however, settling in these lines mustbe eliminated.

The impact of magnetite on the life ofpipes, pumps, and valves is not well defined.The data available do not show major wearof equipment; however, since the processonly developed several years ago, there is nosufficient time to monitor this aspect of theprocess.

Another major area that requires fur-ther research and assessment is the mixingand aeration requirements of the BioMagprocess. Mixing is a crucial part of theprocess, not only to contact solids with mag-netite, but also to prevent the mixed liquorstratification. The high-dense flocs can easilysettle down in aeration tanks; hence, addi-tional mixers would be necessary to keep theflocs in suspension all the time. Mixing canbe very energy intensive and could notably

increase the operating cost. Other than mix-ing, the impact of magnetite addition onalpha value (ratio of process-to-clean-watermass transfer) has to be clearly identified.The issue has been addressed in several proj-ects; however, further research is essential todetermine this value, which has a major im-pact on aeration requirement of the process.

Addition of magnetite into biologicalflocs would vary the coagulation and floccu-lation kinetics, and the role and dose of co-agulants in a magnetite-introduced processneeds to be evaluated. The facility mightneed to change the chemical conditionerand/or dose, and to conduct optimizationstudies. The pH and alkalinity responsewould also have to be monitored.

Foaming was a major problem of theBioMag process that was identified at theSturbridge WWTP (Figure 3). Followingstartup of the facility’s new BioMag system,foaming was observed in each of the packagetreatment units. Microscopic examination ofthe facility’s mixed liquor indicated thatmuch of this foaming is attributable to mi-crothrix parvicella and nocardia bacteria. Theabundance of filaments observed at startupwas believed to be due to the prevalence ofthese bacteria during temporary treatmentsystem operation (Catlow & Woodard,2012); however, this issue has to be investi-gated comprehensively. The facility tried var-ious methods to resolve foaming issues, suchas RAS chlorination, defoamers, and surfacewasting. Surface wasting was identified as themost effective method to address the foam-ing issue; however, it was labor intensive.

Fate of residual magnetite that is wastedthrough WAS (the capture rate is around 95percent) is also not known at this stage. Ac-cumulation of magnetite in solids processes(such as digesters) could be problematic.Furthermore, the impact of magnetite in de-watering processes has not yet been reported.

Another important consideration iscontinuous facility operation while retro-fitting the BioMag process into the existingfacility. During retrofitting, when severalprocess units were offline, the facility still hasto meet the permit requirements; temporaryunits, flow diversion, and various modifica-tions might be necessary, especially in wetweather events.

A Case Study: Comparison of the Biomag Process With Conventional Technologies

The Marlay Taylor Water ReclamationFacility (WRF) in Maryland has a new per-mit to reduce the effluent nitrogen and phos-

Figure 3. Foaming Observed at Sturbridge Wastewater Treatment Plant (from Catlow & Woodard, 2012)



phorus loads from the facility to ENR levelsand to achieve 3mg/L TN and 0.3 mg/L TP;the WRF has explored cost- and energy-ef-fective solutions to upgrade the facility tomeet these ENR requirements. Three processalternatives were compared for requiredfootprint and initial capital cost, along witha 15-year present-worth analysis. The four-stage Bardenpho process was selected for theconventional alternative, and integratedfixed-film activated sludge (IFAS) was alsoused for comparison. In this facility, the foot-print of the BioMag process was found to besignificantly smaller than other options,since this process eliminates the need foradding a secondary clarifier and effluent fil-ters (Figure 4).

Since the BioMag process eliminates theneed for building additional units, this alter-native would require notably lower initialcapital costs compared to the conventionalfour-stage Bardenpho and hybrid IFASprocesses. For a 6-mgd annual average flow,the capital cost of BioMag was around 34percent less than the four-stage Bardenphoand 25 percent lower than the IFAS process(Dursun et al., 2012).

On the other hand, the BioMag processwas shown to be energy intensive due to thehigh mixing requirements and additional en-ergy consumption of the process-relatedequipment (Figure 5). Additional mixing,compressors, and shear mills to separate themagnetite from flocs, separators, and pumpswould significantly increase the energy de-mand of the conventional process.

As a basis for comparing the various op-tions, a present-worth analysis was also con-ducted for the WRF. The capital costs wereinflated to 2011 dollars, which represent thepresent worth. Energy and maintenancecosts were multiplied by the annual present-worth factors that provide the present worthfor a series of values for a 15-year period. Aninterest rate of 4.67 percent was used in theanalysis. Figure 6 exhibits the 15-year pres-ent-worth value of each alternative (Dursunet al., 2012).

Based on this analysis, the present-worth value of the three alternatives werequite similar to each other. The conventionalfour-stage Bardenpho process showedslightly higher value compared to the othertwo alternatives.

Conclusions

The BioMag process is a promisingemerging technology that might provide po-tential solutions for WWTPs that have to meetstrict ENR requirements in limited spaces:

� Based on demonstration and pilot-scaleprojects, the process demonstrated itsability to handle high MLSS concentra-tions and to achieve settling at a very highsolids loading rate.

� The process was proven to be successful inachieving ENR levels when adopted indifferent process configurations and usedto treat a wide variation of flows andloads.

� The BioMag process would provide morecapacity without building additionalunit(s) in treatment plants, while meetingtighter ENR requirements.

However, the process has to be imple-mented full scale to establish more details of theprocess that are not clearly identified at thispoint. Besides many advantages, the process hassome challenges, such as conveyance of solids,air and mixing requirements, equipment wear,foaming, the role of coagulants/chemicals, andthe fate of residual magnetite in biosolidprocesses. These areas require more researchand investigation. The initial capital costs forthe implementation of the process are relativelylow compared to conventional processes. Onthe other hand, the process might be energy in-tensive compared to other options.

Figure 5. Comparison of Energy Requirement

Figure 4. Comparison of Process Footprint (Required Area/Flow to be Treated)


References

• Andryszak R., Woodard S., Nash K., Duffy K.(2011) Enhanced Nutrient Removal Up-

grade of the Winebrenner Wastewater Treat-ment Plant Using BioMag™ Technology,WEFTEC Proceedings, Los Angeles, CA.

• Catlow I., Woodard S. (2009) Ballasted Bi-ological Treatment Process Removes Nu-trients and Doubles Plant Capacity,

WEFTEC Proceedings, Orlando, FL.• Catlow I., Woodard S. (2012) Startup of the

Nation’s First Combined BioMag/CoMagTreatment Facility: Challenges and Successes,WEFTEC Proceedings, New Orleans, LA.

• Dursun D., Jimenez J., Briggs A. (2012)Comparison of Process Alternatives forEnhanced Nutrient Removal: Perspectiveson Energy Requirements and Costs,WEFTEC Proceedings, New Orleans, LA.

• Lubenow B.L., Woodard S., Stewart D.W.,Kirkham R.A. (2011) Maximizing NutrientRemoval in an Existing SBR With a Full-Scale BioMag Demonstration, WEFTECProceedings, Los Angeles, CA.

• Moody M.B, Bishop A., McConnell W.C.(2011) Beyond Desktop Evaluation: KeyDesign Criteria for Mixing and Settling ofMagnetite-Impregnated Mixed Liquor,WEFTEC Proceedings, Los Angeles, CA.

• Naik K., and Strenstrom M. (2011) Eco-nomic and Feasibility Analysis of ProcessSelection and Resource Allocation in De-centralized Wastewater Treatment for De-veloping Regions, WEFTEC Proceedings,Los Angeles, CA.

• U.S. EPA (2009), Nutrient Control DesignManual EPA 600-R-09-012, Cincinnati,OH. ��

Figure 6. Present-Worth Analysis for Marlay Taylor Water Reclamation Facility




FREE BBQ DINNER

� Monday, March 24, 4:30 p.m. �

COURSES

SCHEDULE

Florida Water & Pollution Control Operators Association

FWPCOA STATE SHORT SCHOOLMarch 24 - 28, 2014

Indian River State College - Main Campus

– FORT PIERCE –

Backflow Prevention Assembly Tester ..........................$375/$405

Backflow Prevention Assembly Repairer ......................$275/$305

Backflow Tester Recertification ......................................$85/$115

Basic Electrical and Instrumentation ............................$225/$255

Facility Management Module I ......................................$275/$305

Reclaimed Water Distribution C, B & A ........................$225/$255(Abbreviated Course) ................................................$125/$155

Stormwater Management C & B ...................................$260/$290

Stormwater Management A .........................................$275/$305

Utility Customer Relations I, II & III................................$260/$290

Utilities Maintenance ....................................................$225/$255

Wastewater Collection System Operator C, B & A ......$225/$255

Water Distribution System Operator Level 3, 2 & 1 ......$225/$255

Wastewater Process Control ........................................$225/$255

Wastewater Sampling for Industrial Pretreatment& Operators................................................................$160/$190

Wastewater Troubleshooting ........................................$225/$255

Water Troubleshooting ..................................................$225/$255

CHECK-IN: March 23, 20141:00 p.m. to 3:00 p.m.

CLASSES: Monday – Thursday........8:00 a.m. to 4:30 p.m.

Friday........8:00 a.m. to noon

For further information on the school, including course registration forms and hotels, download the school announcement at www.fwpcoa.org/fwpcoaFiles/upload/2014SpringSchool.pdf

3209 Virginia AveFort Pierce, FL 34981

For more information call the

FWPCOA Training Office 321-383-9690

FWPCOA STATE SHORT SCHOOL


Kevin M. Vickers

Last Octoberbrought cooler weatherand the annual FloridaWater Festival to central

Florida. Sponsored by the Central FloridaChapter of FWEA, the third annual festivalwas hosted at Crane’s Roost Park in AltamonteSprings on October 26. And what a successthis event has become! Over 400 attendeesjoined volunteers and vendors to celebratewater, our most precious resource. The par-ticipants enjoyed live music, food, and facepainting, all while learning a little more aboutthe importance of water. Some attendees wereeven able to have caricatures of themselvesdrawn at the caricature booth.

One of the main events each year at the fes-tival is the annual Walk for Water. Participants areseparated into age groups and compete by carry-ing as many one-gallon water jugs as they canaround the park track. Scores for the event werebased on the number of gallons and the total dis-tance that each participant walked. The Walk forWater is an event that helps participants appreci-ate the weight of water and the effort that is re-quired to transport it over long distances, as isdone in many developing countries (mostly bywomen and children) every day. This year, the

event grew to 67 participants. Combined, they car-ried a total 214 gallons of water over 89 total miles.Congratulations to this year’s overall winner, JohnMercer, who walked a total of 20 gallon-miles.

Another very popular event is the studentdesign competition. Students were challengedwith designing and constructing a water filtra-tion system. Then, each competitor system wastested with two cups of contaminated water.Filtration systems were judged for total volumepassing the filter in 10 minutes and the turbid-ity after filtration. Congratulations to this year’swinners: Kaitlyn Bowman, Eliza Middleton,and Kyle Koehne from Milwee Middle School.

Several exhibitor booths were set uparound the park, representing Reiss Engineer-ing, South Florida Water Management District,

Third Annual Water Festival a Huge Success

Many attendees visited the face painting booth.


City of Sanford, Florida Water and PollutionControl Operators Association, City of Or-lando Wastewater Division, City of AltamonteSprings, American Society of Civil Engineers,Seminole County Conservation, SeminoleCounty Water Shed Management, GreenEdge/FWEA Biosolids, City of Mount Dora,and UF/IFAS Master Gardener Program.

This year’s festival was free to attendees andwas made possible by generous volunteers andsponsors. Many thanks to the volunteers who

helped organize and run the event, and a specialthank you to our sponsors: Hazen and Sawyer,CH2M HILL, City of Orlando, Orlando Utili-ties Commission, Florida Water EnvironmentAssociation, AECOM, Barnes Ferland & Asso-ciates, Carollo Engineers, CPH, FWPCOA, Gar-ney Construction, HDR, MTS Environmental,Reiss Environmental, Arcadis, Brindley Pietersand Associates, CDM Smith, Green Technolo-gies, Heyward, Neel-Schaffer, and Tetra Tech.

The Central Florida Chapter has already

begun planning for this year’s event. If youare interested in helping, please contact theFlorida Water Festival Committee ChairStacey Smich ([email protected]). Foradditional information and pictures of the2013 festival, check out the Florida Water Fes-tival’s Facebook page (https://www.face-book.com/FloridaWaterFestival).

Kevin M. Vickers, E.I., is project engineer withKimley-Horn and Associates Inc. in Ocala. ��

Participants in the student design competition test theirfilters.

Participants on the Walk for Water. Students in the student design competition wait forthe results from the judges.

Wow—2014 hasarrived! It ishard for me to

imagine that another year has passed. As Iget older, the years seem to go by faster andfaster; it must have something to do with thespace—time continuum! As I reflect on thispast year as your president, I am once againhumbled by the support of the industry, andespecially the members of our Associationwho help move this great organization for-ward. Our industry as a whole continues tobenefit as our members are educated bythose who have practical experience in thethings that we do. I hope that 2014 will be a

successful and prosperous year for all!

Final 2013 Board Meeting

The board of directors met last Novem-ber and several notable matters transpired.The board voted to put on a backflow testercourse at the Pinellas County Technical In-stitute (P-Tech) at no cost. This training ef-fort is to show our appreciation for thecontinued support P-Tech (an appropriateacronym for anyone in our industry!) hasrendered over the years.

Brad Hayes with the Florida Water En-vironment Association (FWEA) attendedthe meeting and thanked FWPCOA for ourcontinued support of the Operator’s Chal-lenge. If you don’t know, this is an annualcompetition for teams of utility personnel

from across the United States. The timedcompetition challenges the knowledge andabilities of the teams in the areas of processcontrol, safety, maintenance, collections,and laboratory procedures. This is truly anoutstanding event that our sister organiza-tion puts on and I encourage your utility, orbetter yet, your region, to put together ateam and compete in this event. For moreinformation on the Operator’s Challenge,please visit www.fwea.org.

Our Awards Committee chair, ReneMoticker, gave a brief report on the com-mittee’s activities. Rene reminded our re-gional directors of the FWPCOA awardsprogram. She asked the directors to remindtheir membership to submit nominationsfor our awards that will be given out at theFlorida Water Resource Conference in April,and for those that will be given out at ourAugust awards banquet. Although thesedates seem far in the future, they will be herebefore you know it. One of the best thingswe do as an organization is to recognize ex-cellence in our industry. Please take the timeto nominate those worthy for the recogni-tion that they deserve. The award criteriaand applications can be found at www.fwp-coa.org/awards.asp.

The election of officers took place at theNovember meeting and the current slate ofofficers will server another term: Dave Clan-ton (secretary-elect), Rim Bishop (secre-tary), Ray Bordner (past president), DaveDenny (vice president), and myself (presi-dent) will serve as the executive board in2014. I am truly thankful to have the oppor-tunity to work with such an outstandinggroup of people for another year. Please donot hesitate to contact anyone of us with anyconcerns, suggestions, or training requeststhat you might have and we will work as ateam to make your inquiry meet your ex-pectations.

Webmaster Recognition

Speaking of recognition, I would like tohighlight the efforts of the Association’swebmaster, Walt Smyser. Walt has supportedthe Association on both a regional and state


Jeff PoteetPresident, FWPCOA

Awards, Web Recognition, and Training Opportunities

C FACTOR

level for many years. He is extremely re-sponsive to the requests from our member-ship and continually offers solutions toissues that arise from time to time. An ex-ample of this would be a recent request bythis magazine to implement an automaticlink from our website job board to its web-site. Walt immediately tackled this task andfound a solution that met everyone’s needs.Walt’s knowledge of the industry has bene-fited the Association on many levels. Thankyou, Walt, for your efforts and continuedcontributions!

Education and Training Goals

At the beginning of my tenure as yourpresident I had set several goals. Many ofthese challenges were accomplished as ourtraining programs have expanded and all ofour regions have held training opportunitiesfor their membership. However, the mem-bership goal I set—an optimistic one—didnot come to fruition. In order for our organ-ization to continue to grow, we need to findways to expand our membership.

The expansion of our membershipneeds to occur in two areas: total member-ship and members who are engaged in theAssociation. Both of these areas have chal-lenged past presidents during their tenures.This past year, I visited several of our regionsin an effort to find out what they are doingthat makes them successful. I was hoping tosee more involvement; however, it seems tome that there are core individuals who are in-trinsically driven that help make their regionssuccessful. I personally believe if we get more

of our current members engaged in the As-sociation that our total membership will in-crease as a result of their enthusiasm.Therefore, in my second term as your presi-dent, I am going to focus on ways to get ourcurrent members more involved.

In 2014, we will have some outstandingtraining opportunities for those who want to ex-panded their knowledge and, at the same time,acquire continuing educations credits for licenserenewal. The FWPCOA will have two state shortschools this year: one in March and another inAugust. The Spring Short School, to be held

March 24-28, will be hosted at the Indian RiverState College and applications are available on-line. If you are unable to attend one of the stateschools, there will be training offered by all 13of our regions. If you are looking for some on-line training, our online program has expandedover the years and has an array of topics tochoose from. Please see our website (www.fwp-coa.org) for more information on the Associa-tion and additional regional information.

Our next board meeting will be held inHollywood on January 11. I hope to see youthere! ��


ENGINEERING DIRECTORY

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Engineering • Inspection

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ENGINEERING DIRECTORY

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[email protected]

EQUIPMENT & SERVICES DIRECTORY

Contact Mike Delaney at 352-241-6006

Fort Lauderdale954.351.9256

Gainseville352.335.7991

West Palm Beach561.904.7400

Jacksonville904.733.9119

Key West305.294.1645

Miami305.443.6401

Navarro850.939.8300

Orlando407.423.0030

Tampa813.874.0777 813.386.1990

Naples239.596.1715



CentralFloridaControls,Inc.

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On-Site Water Meter Calibrations

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Installation and System Start-up

Lift Station Controls Service and Repair

Instrumentation,Controls Specialists

Florida Certified in water meter testing and repair

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CEC Motor & Utility Services, LLC1751 12th Street EastPalmetto, FL. 34221

Phone - 941-845-1030Fax – 941-845-1049

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• Motor & Pump Services Test Loaded up to 4000HP, 4160-Volts

• Premier Distributor for Worldwide Hyundai Motors up to 35,000HP

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• UL 508A Panel Shop, engineer/design/build/install/commission

• Lift Station Rehabilitation Services, GC License # CGC1520078

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• Authorized Sales & Service for Aurora Vertical Hollow Shaft Motors

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C L A S S I F I E D SPosi t ions Avai lable

Purchase Private Utilities and Operating RoutesFlorida Corporation is interested in expanding it’s market in Florida.We would like you and your company to join us. We will buy orpartner for your utility or operations business. Call Carl Smith at 727-835-9522. E-mail: [email protected]

WATER PLANT OPERATORCITY OF TEMPLE TERRACE

Technical work in the operation of a water treatment plant andauxiliary facilities on an assigned shift. Performs quality control labtests and other analyses, monthly regulatory reports, and minoradjustments and repairs to plant equipment. Applicant must haveState of Florida D.E.P. Class “A”, “B”, or “C’ Drinking WaterCertification at time of application. Salary Ranges – “A”-$17.33 –26.01; “B”-$15.76-23.65; “C”-$14.33-21.50. Excellent benefitspackage. To apply and/or obtain more details contact City of TempleTerrace, Florida, Human Resources at (813) 506-6430 or visitwww.templeterrace.com. EOE/DFWP

AECOM is recruiting for a Project Engineer position in the Fort Myers, Florida office.

Candidate must have a minimum of BSCE and be licensed and/orregistered as professional engineer in Florida with 5-10 years ofexperience. Preferred Qualifications: Experience on pipe networkmodeling, pump station hydraulics, civil/mechanical design, waterand wastewater treatment facilities, preparation of design drawingsand technical specifications, and technical writing; Participation inprofessional organizations is strongly encouraged; Must have strongverbal and written communication skills. For more details and toapply online: www.www.aecom.com/Careers by indicating 90605BR:Project Engineer.

CITY OF WINTER GARDEN – POSITIONS AVAILABLE

The City of Winter Garden is currently accepting applications for the following positions:

- Wastewater Plant Operator Class C- Water Plant Operator Class C- Collection Field Tech - I- Collection Field Tech II- Utilities Operator II- Customer Service Technician I

Please visit our website at www.cwgdn.com for complete jobdescriptions and employment application. Applications may besubmitted online, emailed to [email protected] or faxed to 407-877-2795.

We are currently accepting employment applications for the following positions:

Water & Wastewater Licensed Operator’s – positions are available inthe following counties: Pasco, Polk, Highlands, Lee

Instrumentation Technician – Pasco

Maintenance Technicians – positions are available in the followinglocations: Jacksonville, Lake, Marion, Ocala and Palatka

Employment is available for F/T, P/T and Subcontract opportunitiesPlease visit our website at www.uswatercorp.com

(Employment application is available in our website)4939 Cross Bayou Blvd.

New Port Richey, FL 34652Toll Free: 1-866-753-8292

Fax: (727) 848-7701E-Mail: [email protected]

Water and Wastewater Utility Operations, Maintenance,Engineering, Management


Utilities Treatment Plant Operators & Trainees$41,138-$57,885/yr plus $50/biweekly for “B” lic.; 100/biweekly for “A”lic. Class “C” FL Operator Lic. required. Accepting unlicensedapplicants also, $37K. Apply: HR Dept., 100 W. Atlantic Blvd.,Pompano Beach, FL 33060. Open until filled. E/O/E. Visithttp://pompanobeachfl.gov for details.

Utility Operations SuperintendentCity of Fernandina Beach

The City of Fernandina Beach is seeking a Utility OperationsSuperintendent to oversee the operations, maintenance, andconstruction for the City’s sewer system located on Amelia Island. Itrequires a Florida State Class B Wastewater Operators license, CDLClass B Florida Driver’s License with tanker endorsement and 10 yearsprogressive supervisory experience in Utility operations. Salary rangeis $45,018 to $70,903. Interested candidates can apply on the City ofFernandina Beach’s web site at http://www.fbfl.us

Town of Lake Placid, FloridaDirector of Utilities

Civil Engineering Degree or Finance Degree preferred. Experience inmanaging and operating water and wastewater systems required.Experience in financial issues involving the management, operationand acquisition of utilities is required. Prefer that applicant have atleast a Florida dual “C” Certification in water and wastewatertreatment or ability to obtain within three months of hire.

Interested parties may mail resumes to Town Administrator by emailat [email protected], 311 W. Interlake Blvd, Lake Placid, FL33852. Download job description and emp. application from websiteat: www.lakeplacidfl.net. EOE/DFWP.

Utility Systems Manager - Pembroke Pines, FLU.S. Water Services Corporation is accepting applications for afull time Utility Systems Manager position in the City ofPembroke Pines Operation.

MANAGER CHARACTERISTICS: This is a management position responsible for supervising andmanaging the operation of assigned utility systems and requires abilityto exercise professional judgment and discretion in directingemployees. The ability to work well with others and solve complexproblems with minimal supervision while adhering to companypolicies and procedures is also required. Confident presence isnecessary when addressing a Private, Municipal, or other Governmententities either directly, or within Council or Owner Board Meetings.Understanding fiscal contract management is required.

QUALIFICATION REQUIREMENTS: 1. Possess experience in the Water and Wastewater Utility Service

Industry as a Total Utility System Manager (Utility Operations,Maintenance, Distribution and Collection Management, withCustomer Service oversight).

2. Minimum five years of successful hands on experience in utilityoperations as a system operator.

3. Completion of special educational programs related to supervisoryand management techniques is preferred.

4. Dual Water and Wastewater Certifications Preferred.

Licenses & Certificates:1. Possess a valid Florida Class C driver's license in compliance with

adopted Company driving standards.2. Possess Dual State Water and Wastewater Treatment Operator

Certificates.

Knowledge of:1. The operation and maintenance of pumps, motors, pressure

regulation equipment, chemical feed equipment and electronicautomatic control systems.

2. Applicable City, State and Federal codes regarding utility systemoperation and maintenance.

3. Administrative principles and methods, including goal setting,program development, scheduling, budget preparation andadministration, cost containment and employee supervision.

4. Principles, practices, and techniques of municipal public worksfunctions, including water and

wastewater activities.

Skill in:1. Supervising, training, motivating and evaluating staff.2. Exercising sound independent judgment within established

guidelines.3. Organizing work, setting priorities, meeting critical deadlines and

completing assignments with minimal supervision.4. Exercising resourcefulness in meeting and resolving problems.5. Representing the Company effectively in meetings with others.6. Use of common office software including Microsoft Office.7. Managing Budgets, Job Costing and Profitability.

For a complete job description, please visit our website atwww.uswatercorp.com

U.S. Water offers a competitive compensation and benefits packagealong with a strong growth-oriented working environment.

SALARY:The Salary Range for this position will be $90,000-$105,000.

United States Sugar CorpClewiston Florida is accepting applications for State Certified Wateroperators. All applicants must hold a minimum of a Class C WTPlicense as issued by the State of Florida. Current Pay scale:

C – $ 19.70B – $ 22.88A – $ 24.15

Email your resume to [email protected] ORApply online at www.ussugar.com


Shop Mechanics and Field Service Tech WantedManufactures repair and service facility is looking for quality peoplein the Orlando and Tampa area.

Shop mechanics: Must be experienced in pumps and motors repairs,minimum.

Field Service Tech: Must be experience in pumps, lift stations andcontrol panels. Must have a valid driver’s license and know how tooperate the Autocrane on the truck.Excellent benefit package with employee medical paid, 401K,vacations and holidays.Equal Opportunity Employer. Please send resumes [email protected] or fax to 407-330-3404

Posi t ions WantedTHOMAS WIERDA – Holds a Florida C Wastewater license and is seekinga part time position in a package or regular plant. Prefers southwestFlorida, Lee, Collier or Charlotte counties. Contact at 1786 Emerald CoveCircle, Cape Coral, Fl. 33991. 239-462-4085

STANFORD KNIGHT – Holds a Florida C Wastewater and C Water licensewith 10 years experience. Prefers the central Florida area but is willing torelocate. Contact at 1030 NW 118th St, Miami, Fl. 33168. 786-439-7317

BRIAN WEIGHTMAN – Has passed his C Water and Wastewater coursesand needs additional plant time. Has also taken Advanced & IndustrialWastewater 1 & 2. Proficient in Chemistry and Math(Teaches classes in thesesubjects). Prefers central Florida and east coast area and is willing to relocate.Contact at 1363 Wayne Ave., New Smyrna Beach, Fl. 32168. 386-478-9942

DARYL BROWN – Holds a Florida B Wastewater and C Water license withsix years experience. Prefers the Orlando, Winter Park or Winter Gardenarea of the state. Contact at 5445 Limelight Circle, Orlando, Fl. 32839.407-692-3333

From page 59

1. C) RotiferBeginning with the lowest life form, themicroorganism indicators are amoebas, smallflagellates, large flagellates, free swimmingciliates, stalk ciliates, rotifers, nematodes (worms)and water bears. So, of the three indicators listedin the question, the rotifer is the highest life formin the activated sludge process.

2. A) 19.3 lbs/day/ft2

FormulaTotal lbs per day entering the secondary clarifier÷ Total clarifier surface area in ft2

Total lbs per day entering the secondary clarifier = (5.5 mgd + 2.75 mgd) x 2,200 mg/L x 8.34lbs/gal = 151,371 lbs per day

Clarifier surface area = 3.14 x (50 ft x 50 ft) = 7,850 ft2

= 151,371 lbs per day ÷ 7,850 ft2

= 19.28 lbs per day per ft2

3. B) A strong influent waste strength.The term “loading” refers to the demand foroxygen placed on the activated sludge processfrom the flow being treated. A shock load is ahigh demand for oxygen (from CBOD5, COD ornitrogen) placed on the activated sludge processin a short period of time.

4. C) Low aeration DOBecause denitrification is an anoxic reaction, lowdissolved oxygen levels in the aeration tank willtypically result in the best denitrificationefficiency.

5. B) FermentationThe fermentation zone of a Bardenpho processreceives raw wastewater (usually after

preliminary treatment) and return activatedsludge (from secondary clarifiers). The MLSS ismixed and not aerated in the fermentation zonefor a time period of about 1 to 3 hours. Thiszone, absent of all sources of oxygen, basicallyactivates a group of phosphorus accumulatingorganisms (PAO), which trade phosphorus forCBOD5. These bugs release phosphorus fromtheir cells and “grab onto” food for laterdecomposition. A successful fermentation zonewill have phosphorus levels in the outlet abouttwo to four times higher than the inlet to thetank.

6. C) AutotrophicThere are two main groups of autotrophicbacteria that are responsible for the conversion ofinorganic ammonia to nitrate. The first group,called nitrosomonas (known as ammonia-oxidizing bacteria), convert ammonia to nitrite.The second group, called nitrobacter (known asnitrite-oxidizing bacteria), convert nitrite tonitrate. The process of nitrification does notnecessarily remove nitrogen from the wastewater;it only converts it to a more stable form.

7. D) Endogenous respirationEndogenous respiration takes place when thesludge is very old and food availability is very low(low F/M ratio, high SRT). This conditionencourages active bacteria still hungry to“cannibalize” other bacteria to find andassimilate their uneaten food (carbon) value.Endogenous respiration is known as “survival ofthe fittest,” and is on the far right side of thegrowth curve.

8. A) HeterotrophicFacultative heterotrophic bacteria are responsiblefor the conversion of nitrate (NO3) to freenitrogen gas (N2) in the absence of dissolvedoxygen. This activity, called denitrification,consumes some CBOD5 in the process.

9. A) 7.2 lbsNitrification consumes alkalinity at the rate ofabout 7.2 lbs of alkalinity for each lb of ammoniaoxidized. Because this action causes the mixedliquor pH to drop, biological denitrification isdesirable, which replenishes the alkalinity at arate of about 3.6 lbs of alkalinity for each lb ofnitrate that is consumed as a source of oxygen.The action of denitrification helps to stabilize theMLSS pH in a range acceptable to the nitrifyingbacteria.

10. D) Decrease the RAS rate.The total flow entering an aeration tank is Q plusQR (influent flow plus RAS flow). As the RAS flowis decreased, the contact time through the aerationtank zones is increased, due to a reduction of thetotal flow entering the aeration tank.

Columnist note: Hubert H. Barnes, P.E., mainte-nance superintendent for the City of HollywoodWastewater Treatment Plant, submitted the followingcomment concerning question 8 in this column in theNovember 2013 issue of the Journal. The question andanswer were related to cavitation of a high-servicewater pump.

It is insufficient to say that “This drop in pressurecauses gas pockets to form in the water, which then col-lapse” without explanation that the “gas” is actuallywater vapors, and that they collapse as the pump im-parts pressure energy to overcome the vapor pressureof the fluid. We are talking about a high-service pump,and therefore take it that there are no volatile gasestrapped in the water. The answer also stated that “Thiscan occur when a pump is trying to deliver more waterthat it was designed for.” Pumps do not try to do any-thing; they simply react to the suction and dischargeconditions.

Thank you, Hubert, for your comments and forreading Certification Boulevard. Your response mayhelp other readers who may have been confused aboutthe explanation to that question.Roy

Certification Boulevard Answer Key

Display Advertiser Index


Arcadis ....................................................78Blue Planet ..............................................15CEU Challenge ..........................................49CROM ......................................................57Data Flow ................................................41FSAWWA Drop Savers ..............................40FSAWWA Legislation Day ..........................68FSAWWA Operator Awards........................47FSAWWA Training ....................................61FWEA Collection System ..........................71

FWPCOA Short School ..............................67FWPCOA Training ......................................53Florida Water Resources Conference ..23-28Garney........................................................5Gerber Pumps E.C.....................................21GML Coatings ......................................45,66Hudson Pumps ........................................35ISA............................................................78McKim & Creed ........................................13Oldcastle ..................................................69

Polston ................................................10-11Rangeline ................................................79Regional Engineering ................................48Reiss Rngineering ....................................31Stacon ........................................................2Stantec ....................................................71Treeo ........................................................20US Water ..................................................43Wade Trim ................................................70Xylem ......................................................80

Editorial Calendar

January . . .Wastewater TreatmentFebruary . . .Water Supply; . . . . . . . . . .Alternative Sources

March . . . . .Energy Efficiency; . . . . . . . . . .Environmental Stewardship

April . . . . . .Conservation and Reuse; . . . . . . . . . .Florida Water Resources . . . . . . . . . .Conference

May . . . . . . .Operations and UtilitiesManagement

June . . . . . .Biosolids Management andBioenergy Production;

. . . . . . . . . .FWRC ReviewJuly . . . . . .Stormwater Management; . . . . . . . . . .Emerging Technologies

August . . . .Disinfection; Water QualitySeptember .Emerging Issues; . . . . . . . . . .Water Resources

ManagementOctober . . .New Facilities, Expansions

and UpgradesNovember .Water TreatmentDecember .Distribution and Collection

Technical articles are usuallyscheduled several months in advance andare due 60 days before the issue month(for example, January 1 for the Marchissue).

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florida water resource journal jan 2014

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