mark b. mcneal, p.g. 2004.pdf · mark b. mcneal, p.g. february 11, 2004 environmental permitting...
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Reclaimed Water ASR Permitting
Presented at the Presented at the
Presented byPresented by
Mark B. McNeal, P.G.Mark B. McNeal, P.G.
February 11, 2004February 11, 2004Environmental Permitting Environmental Permitting Short CourseShort CourseSponsored bySponsored by
Florida Chamber of ConferenceFlorida Chamber of Conference
Rosen Plaza HotelRosen Plaza HotelOrlando, FloridaOrlando, Florida
Today’s Presentation
• Introduction• ASR Feasibility• Technical Issues• Summary
PotentialSupply Deficit
PotentialExcess Supply
Mature reuse systems face supply and demand imbalances
Jan Feb March April May June July Aug Sept Oct Nov Dec
Incr
easi
ng D
eman
d
Reclaimed WaterDemand
ReclaimedWater Supply
Many storage options are available
ASR Wells
Surface Reservoirs
?????Above Ground Storage Tanks
Problem: 600 MG storage needed Problem: 600 MG storage needed Problem: 600 MG storage needed
6 ASR Wells6 ASR Wells•$5 to 6 million cost•3 acres of land•$5 to 6 million cost•3 acres of land
120 - 5MGStorage Tanks120 - 5MGStorage Tanks•>$100 million cost•100s of acres of land•>$100 million cost•100s of acres of land
ASR is most feasible in many cases
Reclaimed Water ASR• The seasonal storage of high quality
reclaimed water in a suitable aquifer during periods of low demand, for subsequent recovery during periods of high demand for beneficial use
• Different from deep well injection which is designed to dispose of effluent that does not necessarily meet reuse standards
Conceptual Reclaimed Water ASR Well
Class V, Group 3Class V, Group 3Injection WellInjection Well
Typical Recovery OperationTypical Recovery Operation(Excess Demand)(Excess Demand)
WRF orWRF orAWTPAWTP
Public AccessReuse System
Typical Recharge OperationTypical Recharge Operation(Excess Supply)(Excess Supply)
Public AccessReuse System
WRF orWRF orAWTPAWTP
Class V, Group 3Class V, Group 3Injection WellInjection Well
Zone of poor quality water
Low Permeability
Zone
Moderate Permeability
Zone
Low Permeability
Zone
>1,000mg/L TDS
Reclaimed water ASR programs are developing quickly along Florida’s west coast
Bonita Springs
Cycle Testing Initiated
South HillsboroughSt. Petersburg
SouthwestManatee County
Sarasota County
Lehigh Acres
Marco Island WWTP
Central Hillsborough
Manatee County North
City of Sarasota
Englewood
Northwest Hillsborough
Pinellas CountyLargo
Clearwater
Construction Permit IssuedASR Well Drilled
Feasibility Study
(2)
(5)
(7+)
Florida is out in front nationally in development of reclaimed water ASR
• Other states are less comfortable with reclaimed water use
• Artificial recharge and indirect potable reuse are more active elsewhere
• Other areas appear to be lagging in matching the quality of water to intended use
IDID--11
Reclaimed water ASR will become more widespread in the near future• Similar projects are underway in
– Arizona - Australia– California - Washington
• Other states recognize the need but must develop regulatory framework– South Carolina -- North Carolina– Georgia --Texas
• Yet other states must still become more comfortable with reuse
ASR will be the key to successful optimization of many reuse programs
• Reuse is often limited to 50 to 60 percent of annual ADF without seasonal storage for many Florida reuse systems
• ASR development in many cases–is the lowest cost option to expand reuse–has the lowest land requirements–is environmentally sensitive–has no negative aesthetics
Reclaimed water ASR programs take several years to implement
• Feasibility Study (3 to 6 months)• Permitting (10 to 15 months)• Well Construction (6 to 12 months)• Operational testing (2 to 4 years)
July 2001August 1996 January 1997
A feasibility study is important to address ASR preliminary issues• Supply and demand issues • Well siting • Reclaimed water
characterization• Existing wastewater
infrastructure and reuse system• Existing groundwater users• Native water quality and
hydrogeology• Drilling and testing program
Native water quality and hydrogeology drive selection of optimum storage zone and permitting strategy
Permitting Not Feasible
Limited Recovery
Proper Storage Zone SelectionMaximizes Recovery And Aids in
Permit Approval
Permitting for Reclaimed Water ASR Systems Similar to Potable Water ASR
• Technical Advisory Committee Formed– FDEP local and Tallahassee– Local WMD– EPA– County DOH– Other County agencies
• WMD Water Use Permit still required– Truly a Zero-Consumptive-Use permit– Should be relatively straight forward
Quality of Aquifer Dictates Effluent Quality Requirements• Greater than 10,000 mg/L TDS
– Secondary treatment only (BOD and TSS limits)– Similar to Deep Injection Wells
• Between 3,000 and 10,000 mg/L TDS– All primary DWSs– Secondary DWSs “waived”– Minimum criteria (“free-froms”)
• Between 1,000 and 3,000 mg/L TDS– As above, but Secondary DWSs also regulated
• Less than 1,000 mg/L TDS (62-610, FAC)– Same as above plus additional TOC and TOX limits
The reclaimed water must meet all primary Drinking Water Standards• Phthalate concerns may have to be addressed• Disinfection by-products can be successfully
addressed through chloramination– TTHMs reduced from 175 ppb to 30 ppb at NW
Hillsborough Co.• Nitrogen series may also
require process changes– Nitrate of <10 mg/L– Nitrite of <1 mg/L– Ammonia is not regulated
Coliform standards must be met at the well• Total coliform of 4 cfu/100 mL; not a reuse - but
a groundwater discharge - standard– Reuse systems are not sterile conveyance systems, not
constructed/operated as a drinking water system – Chloramines are more persistent than free chlorine,
but generally not as strong a disinfectant; maintaining elevated TRC at wellhead should control TC
• Fecal coliform must be (and have been) absent• Alternative disinfection
such as UV may be needed at the wellhead– Capital $80-$150k/well– O&M $3-$5k/year/well
UV
Secondary Drinking Water Standards must also be met
• Secondary DWSs are aesthetic rather than health-based standards– Color -- Manganese -- TDS --pH– Odor -- Iron --Chloride --Sodium
• Ambient groundwater is alternative standard• Exemptions are available and relatively easy to
obtain– WQCEs, ZODs, Chapter 120 Variance
• Regulated as average concentrations, rather than single sample exceedence
Initial test results from EWD are encouraging
• Storage zone is saline – 20,000 mg/L TDS– No other beneficial use
• 90 MG was recharged during first cycle– Only 12 MG was recovered – Due to lack of reuse demand not
water quality – Recovered water quality approached
1,100 mg/L TDS
• Approximately 450 mg currently in storage– 10 mg recovered with TDS approximately 500 mg/L
• Recovery efficiency showing improvement w/ increased storage
Blending of ASR water with reclaimed water will help meet irrigation quality
Water ReclamationFacility
1 mgd @ 2000 mg/L TDS
Chlorine Contact Basin
3 mgd @1000 mg/L TDS
(400 mg/L chlorides)
ASR Well
2000 mg/L TDS
2 mgd @500 mg/L TDS
Cycle testing is an important phase of the ASR program• Operational testing
necessary to justify FDEP operating permit issuance
• Defines recovery potential of the stored water
• Allows demonstration that drinking water standards can be maintained during recharge events, and reuse standards during recovery
Sufficient reject pond capacity provides flexibility during cycle testing
TPW-1Existing
Blowdown Pond
• High turbidity observed for 1 to 2 hours following recovery startup
• Existing pond sited for 15 to 20 minutes of recovery
• Larger pond will allow longer blowdown period during multiple ASR well startups
Reclaimed water ASR projects should be easier to develop than potable ASR• Source water costs “pennies” per 1000
gallons (pumping costs), therefore investment is minimal to develop “bubbles”
• Recovery to approximately twice the salinity of drinking water for many irrigation applications
• No re-treatment should be required prior to placing into the reuse system, following water quality demonstration
Major hurdles have been cleared over the past several years in Florida
PermittingFeasibility
Native water quality
characteri-zation
Authorization to Use
OperatingPermit
Recharge Water
Quality Issues
One hurdle remains . . .
Summary• Sustainable dry season supplies are becoming
increasingly critical for reuse reliability• ASR allows the reuse utility to maximize use
and minimize disposal of this resource• Substantial progress
has been made in Florida to recognize the benefits of reclaimed water ASR
• Further progress is needed to streamline implementation of these programs
Summary (cont.)• Reclaimed water ASR is a new use of a proven
technology to maximize reuse• Favorably received by FL regulatory agencies• May allow utility to transition into a zero-
discharge facility• Economical approach to large volumes of
seasonal storage• Future saltwater intrusion barriers or indirect
potable reuse applications may develop, but additional treatment is likely required
Reclaimed Water ASR Permitting
Presented at the Presented at the
Presented byPresented by
Mark B. McNeal, P.G.Mark B. McNeal, P.G.
February 11, 2004February 11, 2004Environmental Permitting Environmental Permitting Short CourseShort CourseSponsored bySponsored by
Florida Chamber of ConferenceFlorida Chamber of Conference
Rosen Plaza HotelRosen Plaza HotelOrlando, FloridaOrlando, Florida