tryon creek wastewater treatment plan facilities plan

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Executive Summary Introduction Originally constructed in 1964, the Tryon Creek Wastewater Treatment Plant (TCWTP) has provided reliable wastewater treatment for both the City of Portland and City of Lake Oswego. The plant is successfully meeting the current treatment needs of both communities, and it continues to produce a high quality secondary effluent at an extremely low cost per gallon.

This facilities plan takes into account projected growth in wastewater flows and loads and future regulatory requirements. Moreover, it addresses potential modifications to the plant to accommodate community growth as the surrounding neighborhood transitions from an industrial area to a mixture of commercial and residential areas. The plan was developed with a 30-year planning horizon with a focus on the first 10-year increment to provide a long-term road map for improvements. With this plan, a framework is established to make cost-effective, near-term capital improvement program (CIP) decisions, take advantage of advancements in technology, minimize stranded investment, and build a facility that ultimately has the flexibility to meet the long-term regulatory and capacity requirements.

Approach Development of this facilities plan included a review of the study area characteristics comprising the physical environment, population growth projections, land use regulations, and project permitting requirements. Regarding condition and capacity assessments of the wastewater collection systems, this facilities plan relied upon other recent studies conducted for the City of Portland and City of Lake Oswego, but evaluated the condition of the TCWTP facilities using available information and performed high-level process and capacity analyses to confirm existing capacity and sizing of the TCWTP treatment facilities as compared to projected flows and loads.

Planning criteria and evaluation criteria were developed for the TCWTP facilities plan on the basis of City of Portland Bureau of Environmental Services (BES) Strategic Levels of Service (LOS) and the Vision and Guiding Principles developed with stakeholders in the TCWTP including the ten member Citizen Advisory Committee (CAC) and approved by an Oversight Committee (OSC) consisting of elected officials and executive level managers from both the City of Portland and the City of Lake Oswego. To identify the minimum requirements for development of treatment plant alternatives, the Strategic LOS and Vision and Guiding Principles were translated into more specific Tactical LOS.

As part of the facilities planning process, the project team analyzed and documented the various water quality and treatment requirements applicable to the TCWTP within the planning horizon to further define planning/ design criteria for the development and evaluation of alternatives.

Development and Evaluation of Alternatives The project team developed and evaluated whole-plant alternatives for initial screening of overall process unit configurations. This was accompanied by development of conveyance system alternatives pertaining to delivery of flow to the plant to accommodate the various alternatives. In conjunction with this, the project team developed and evaluated unit process technologies, and the results of these evaluations were incorporated into the development of several complete alternatives, which were then evaluated and ranked by the City of Portland BES and Lake Oswego staff based on the evaluation criteria and alternative analysis approach developed by BES and the CAC to identify a preferred alternative.

Low, medium, and high collection system infiltration and inflow reduction scenarios were developed and evaluated to determine the range of potential flow criteria to consider in development of whole-plant alternatives. The range, however, was found to be limited to 10 to 15 percent. With this limited range, it was found to be unlikely that the whole-plant alternative analysis would yield significantly different alternatives for the three scenarios.

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The Vision and Guiding Principles were used as evaluation criteria to compare and rank the viable alternatives and select a preferred alternative.

Based on feedback from BES and Lake Oswego staff, as well as the CAC, the preferred alternative was presented to the OSC on October 15, 2013, for endorsement.

Recommended Plan A process flow diagram of the recommended TCWTP improvements is shown in Figure ES-1. The 30-year recommended plan and a visualization of the facility at the end of the planning horizon are shown in Figures ES-2 and ES-3, respectively. The historic and projected design flows are presented in Table ES-1.

TABLE ES-1 Historic and Projected Design Flows Tryon Creek Wastewater Treatment Plant Facilities Plan

Condition Annual

(Jan–Dec) Wet Weather

(Jan–Apr, Nov–Dec) Dry Weather (May–Oct)

Historic Flows (million gallons per day)*

Average Daily 5.7 6.9 4.5

Maximum Month - 11.2 7.6

Maximum 7-Day - 15.7 9.9

Maximum Day - 29.1 13.6

2020 Flows (million gallons per day)















* Based on historical Daily Monitoring Report (DMR) flow data from January 2007 through December 2011.

Implementation Plan The primary goal of this planning effort was to develop a flexible, dynamic facilities plan that covers potential regulatory, social, environmental, and economic changes. An implementation plan was prepared to allow for the development of a capital plan that can be responsive to changing criteria.

Each component of the recommended plan is recommended on the basis of a distinct need—condition, capacity, performance, regulatory criteria, or some combination thereof—in order to meet endorsed Tactical LOS.

WBG010711142557PDX 432805.03.30.15.50 Rv1 06.20.14

FIGURE ES-1Recommended Plan Process Flow Diagram

Tryon Creek Wastewater Treatment Plant Facilities Plan

FIGURE ES-2Recommended 30-Year Site Plan


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Tryon Creek Wastewater Treatment Plant Facili es Plan Dec. 11, 2013Figure 7-2 RECOMMENDED SITE PLAN - 30 YEAR

PRIMARYEFFLUENT PUMP

STATION

T R Y O N C R E EK

CHEM. STORAGE

WET WEATHER PRIMARYCLARIFIER

BLENDEDSTORAGE

GENSET BLDG

FILTERS(FUTURE)

WASAER.

MAINT.

BLENDEDSTORAGE

PARKING

ENHANCEDBIOFILTER

STORAGEBLDG.

RAS/WASPUMP STATION

ELEC. ROOM

SECONDARYCLARIFIER

NO. 1

SECONDARYCLARIFIER

NO. 2

BIOTOWER

SOLIDSLOADOUT

WAS STORAGE & THICKENING

BASE BIOFILTER

CHLORINECONTACT

AERATIONBASIN

NUTRIENTREMOVAL(FUTURE)

DRY WEATHERPRIMARY CLARIFIER

INFLUENTPS

BLOWER BLDG

EX. P.S.

SECONDARYCLARIFIER

NO. 3

N. S

TATE

ST.

(O

R 43

)

FOOTHILLS RD.

ADMINBLDG

HEADWORKS

SENSITIVE LANDS AREA

WILLAMETTE RIVER GREENWAY

NATURAL RESOURCES AREA

FOOTHILLS PARK

FOOTHILLS DISTRICT FRAMEWORK PLAN

(ADOPTED JULY 2012)

WI

LL

AM

ET

TE

R

IV

ER

NATURAL RESOURCES BUFFER

FIGURE ES-3Recommended 30-Year Site Plan Visualization


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EXECUTIVE SUMMARY

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Five project triggers were considered to develop the implementation plan:

Condition. Condition triggers are based on deteriorating condition of system components. These improvements are recommended to eliminate increased maintenance and reduced performance and reliability associated with the failing component. The condition trigger is also used to bring system components up to current codes and BES standards. Since several unit processes are in the City of Lake Oswego Flood Hazard Area (and Federal Emergency Management Agency 100-year floodplain) and have flooded during historical flood events, flood hardening of structures is also considered a condition trigger.

Ongoing prioritization of improvements within this category should rely on the existing BES asset management program, which regularly evaluates the costs associated with maintaining aged equipment as compared to the risk associated with poor performance and reduced reliability.

Peak Flows. Peak flow triggers are based on the inability of a component to hydraulically pass as well as provide treatment (consistent with current regulatory requirements) for peak flows. BES and the City of Lake Oswego have committed to conveying all flows up to a 25-year storm, and BES is committed to treating all flows that enter the plant. As improvements and capacity upgrades are made to the upstream collection system (to prevent sanitary sewer overflows), additional peak flows will be conveyed to the plant. These treatment plant improvements are then necessary to meet National Pollutant Discharge Elimination System (NPDES) permit requirements.

Performance/Operability. Performance triggers are related to systems or components that simply do not work as intended, could work better, or were poorly designed, requiring excessive maintenance and/or operation time to make the system work. Some performance triggers relate to evolving industry standards, such as increased emphasis on odor control to address the concerns of neighbors who are encroaching on the plant boundary. The prioritization of these improvements is informed by labor and maintenance costs and impacts associated with not moving forward with the proposed improvement. Additionally, there are performance and operability triggered projects that bridge the gap between current and future plant configurations and allow for phased implementation of plant improvements.

Regulatory. Regulatory triggers are those improvements required to address evolving regulatory criteria. The TCWTP is currently in the process of an NPDES permit renewal with the Oregon Department of Environmental Quality. This renewal will likely include the designation of TCWTP as a Class I facility, requiring backup power improvements to meet reliability and redundancy requirements. In the near term (next 5 to 10 years), it is also possible that implementation of the Willamette Basin Standard and/or the elimination of blending will be mandated by regulatory agencies, requiring several secondary process improvements to enhance performance. In the long term, removal of more nutrients (ammonia, nitrogen, and phosphorus) from the discharge is also likely to be required.

Site Enhancements. These improvements are related to the interface between the TCWTP and the adjacent neighborhood and Foothills Park. Industry standards specific to the extent of improvements (e.g., odor control, site access, security, community safety, noise and light mitigation, visual screening, edge treatments, and stormwater management) have increased and are expected to continue to evolve as communities encroach on the boundaries of existing facilities. Base improvements represent those buffer and mitigation components that do not meet current industry standards. Enhanced improvements address a higher level of mitigation expected to be consistent with industry standards by the end of the planning horizon. Enhancement projects will be coupled with process improvement projects where possible for efficiency. Extensive enhancements to facilitate adjacent development are not envisioned as part of this plan, but could be considered if supplemental private funding were provided.

Figure ES-4 presents the anticipated potential timing of each of these process triggers.

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0 5 10 15 20 25 30

Enhanced Edge Treatments

Enhanced Odor Control

Base Edge Treatments

Base Odor Control

Nutrient Removal

Blending

Willamette Basin Standard

Class 1 Reliability

PERFORMANCE/OPERABILITY

CONDITION OF THE PLANT

PEAK FLOWS

Years

REG

ULATO

RY

SITE

ENHANCEM

ENTS

FIGURE ES-4 Project Triggers Timing

In addition to these triggers, the implementation plan considers a variety of criteria including constructability/sequencing, rate impacts to the consumer, continuous maintenance of existing assets, and avoidance of stranded investments. Based on these collective criteria, components of the recommended plan are grouped into project packages. In order to support the proposed sequencing of the recommended plan, some interim improvements are required to bridge the gap between the current and future plant configurations. These pertain specifically to the solids facilities components since they are not likely to be implemented in the first half of the planning horizon.

The recommended CIP is presented in Table ES-2 and illustrated in Figure ES-5. Total construction costs include contractor markups and profit, sales tax, and appropriate contingency. Actual construction costs will depend on a variety of factors such as the final project scope and market conditions at the time of project bidding. Program costs include the total construction costs, but also an additional markup to estimate the costs of engineering design, construction contracting, construction management, project administration, and legal costs.

All costs are in 2013 dollars and are Class 5 estimates. The range of accuracy for a Class 5 cost estimate is broad (+100 percent to –50 percent of the actual construction cost). It is important to communicate the level of accuracy to policymakers, decision-makers within both organizations (Portland BES and Lake Oswego), and stakeholders. This level of accuracy is reasonable for planning work.

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TABLE ES-2 Recommended Capital Improvement Program Tryon Creek Wastewater Treatment Plant Facilities Plan

Package Construction

Cost Program

Cost FY15 FY16 FY17 FY18 FY19 FY20 FY21 FY22 FY23 FY24 FY25–FY40

Headworks/Dry Weather Clarifier Project

$28,640,000 $40,170,000

Land Purchase/ Planning/Permitting

$3,000,000 $4,270,000 $2,135,000 $2,135,000

Design $5,130,000 $2,565,000 $2,565,000

CM/SDC/Overhead $5,130,000 $1,710,000 $1,710,000 $1,710,000

Construction $25,640,000 $25,640,000 $8,547,000 $8,547,000 $8,546,000

Influent Pump Station – Portland

$3,575,000 $5,200,000

Permitting $180,000 $90,000 $90,000

Design $720,000 $360,000 $360,000

CM/SDC/Overhead $720,000 $360,000 $360,000

Construction $3,575,000 $3,580,000 $1,790,000 $1,790,000

Tryon Interceptor Seismic Upgrade – Portland a

$2,530,000 $3,680,000

Permitting $130,000 $65,000 $65,000

Design $510,000 $255,000 $255,000

CM/SDC/Overhead $510,000 $255,000 $255,000

Construction $2,530,000 $2,530,000 $1,265,000 $1,265,000

Influent Piping Modifications – Lake Oswego b

$1,480,000 $2,150,000

Planning/Permitting $70,000 $35,000 $35,000

Design $300,000 $150,000 $150,000

CM/SDC/Overhead $300,000 $150,000 $150,000

Construction $1,480,000 $1,480,000 $740,000 $740,000

Aeration Basin Optimization Project

$4,100,000 $5,960,000

Planning/Permitting $210,000 $210,000

Design $820,000 $820,000

CM/SDC/Overhead $820,000 $410,000 $410,000

Construction $4,100,000 $4,110,000 $2,055,000 $2,055,000

Aeration Basin Capacity Project

$1,270,000 $1,840,000


Design $250,000 $250,000

CM/SDC/Overhead $260,000 $260,000

Construction $1,270,000 $1,270,000 $1,270,000

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TABLE ES-2 Recommended Capital Improvement Program Tryon Creek Wastewater Treatment Plant Facilities Plan

Package Construction

Cost Program

Cost FY15 FY16 FY17 FY18 FY19 FY20 FY21 FY22 FY23 FY24 FY25–FY40

Secondary Clarifier Project

$6,480,000 $9,400,000


Design $1,300,000 $650,000 $650,000

CM/SDC/Overhead $1,300,000 $650,000 $650,000

Construction $6,480,000 $6,480,000 $3,240,000 $3,240,000

Bankside Outfall Project $2,880,000 $4,110,000

Planning/Permitting $150,000 $280,000 $93,333 $93,333 $93,333

Design $550,000 $550,000

CM/SDC/Overhead $550,000 $550,000

Construction $2,730,000 $2,730,000 $2,730,000

Disinfection Project $4,630,000 $6,540,000

Planning/Permitting $370,000 $580,000 $580,000

Design $850,000 $425,000 $425,000

CM/SDC/Overhead $850,000 $425,000 $425,000

Construction $4,260,000 $4,260,000 $2,130,000 $2,130,000

Solids Facilities Project $9,000,000 $13,000,000 $13,000,000

Enhanced Odor Control $4,000,000 $5,800,000 $5,800,000

Nutrient Removal & Filters

$20,700,000 $30,000,000 $30,000,000

Site Access, Buffering, and Security Project

$1,300,000 $1,880,000 $1,880,000

Non-process Buildings Project

$2,600,000 $3,800,000 $3,800,000

RR&M Projects – Near Term

$2,800,000 $4,100,000 $410,000 $410,000 $410,000 $410,000 $410,000 $410,000 $410,000 $410,000 $410,000 $410,000

RR&M Projects – Long Term

$4,400,000 $6,400,000 $6,400,000

Total TCWTP Improvements

$92,800,000 $133,000,000 $2,775,000 $3,365,000 $5,440,000 $15,697,000 $10,667,000 $11,764,333 $1,898,333 $3,768,333 $7,655,000 $9,110,000 $60,880,000

Associated Portland System Improvements a

$6,105,000 $8,880,000 $155,000 $155,000 $615,000 $615,000 $3,670,000 $3,670,000

Associated Lake Oswego System Improvements b

$1,480,000 $2,150,000 $35,000 $185,000 $150,000 $890,000 $890,000

a Costs for Tryon Creek Interceptor Seismic Upgrade are part of a current BES CIP project in progress. b Costs for Lake Oswego Influent Piping Modifications are reflected in Lake Oswego's Collection System Master Plan.

CM = construction management; FY = fiscal year; SDC = service during construction.

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WBG010711142557PDX 432805.03.30.15.50 Rv3 06.23.14

FIGURE ES-5Phased Site Plan


$40,170,000

$5,960,000

$6,540,000

$4,110,000

$9,400,000

$1,840,000

$13,000,000

$3,800,000

$37,680,000

$10,500,000

$133,000,000

2015- 2020

2015- 2018

2020- 2023

2020- 2024

2021- 2024

2022- 2024

AFTER 2024

AFTER 2024

AFTER 2024

2015- 2040

EXECUTIVE SUMMARY

xxvii

Land Use Strategy The TCWTP is located within the City of Lake Oswego, and is, therefore, subject to the land use regulations and permit requirements of this jurisdiction. Expansion or alteration of plant infrastructure requires a land use permit from the City of Lake Oswego and is subject to the review process, criteria, and standards of the Lake Oswego Community Development Code (CDC). This permit comes at the conclusion of a land use application process where the applicant (in this case, Portland BES) must demonstrate to the satisfaction of the City of Lake Oswego that CDC criteria and standards have been met. The City of Lake Oswego’s Development Review Division will oversee the process and apply the code requirements.

The existing process is highly discretionary because of the existing code language. The discretionary nature of the process and the public hearings involved make it critical that BES and Lake Oswego engage the adjoining neighbors and stakeholders in understanding and supporting the required improvements at the TCWTP through early and ongoing public outreach efforts. The involvement of TCWTP-specific groups like the CAC will be an important element of this stakeholder outreach and support effort.

Very recently, BES suggested changes to the Lake Oswego CDC to more effectively address impacts from proposed TCWTP improvements. The suggested changes were to incorporate one of the following optional approaches:

Review planned facility improvements based on objective performance standards rather than the discretionary (subjective) conditional use criteria.

or

Create a master facility planning process that would allow a longer-term, staged approval while mitigating for neighborhood and environmental impacts.

These suggestions are under consideration by the City of Lake Oswego.

BES and Lake Oswego should continue to pursue these optional approaches to provide for greater certainty in the development review process while effectively mitigating existing and potential environmental or neighborhood impacts.

tryon creek wastewater treatment plan facilities plan

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