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June 2006

“Just In Time” Treatment Capacity“Just In Time” Treatment CapacityDevelopers and Utilities Can PartnerDevelopers and Utilities Can Partner

Pima County Wastewater ManagementPima County Wastewater Management

• Located in Southern Arizona

• Population Approaching 1 Million

• 3,300 Miles of Conveyance System

• 2 Major Wastewater Treatment Facilities

• 1 Wastewater Reclamation Facility

• 8 Smaller Outlying Treatment Facilities

• 68 mgd of Treated Wastewater

• $100 million Annual Department Budget

BackgroundBackground

• The Arizona District Population Segment of the pygmy-owl listed as endangered on March 10, 1997

• Critical habitat was designated on July 12, 1999

• Construction was underway for a 12.5 mgd expansion for the Tucson North Basin for completion in 2006

• Development began to move to outlying areas of the Tucson Metropolitan Area where pygmy-owl critical habitat was not designated

• Capacity needs in outlying areas increased and available funding was limited

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BackgroundBackground

ProjectedGrowthBefore1999

BackgroundBackground

PygmyOwl

Habitat

ProjectedGrowthBefore1999

BackgroundBackground

PygmyOwl

Habitat

ProjectedGrowthBefore1999

RedirectedGrowth

After 1999

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BackgroundBackground

• Without expanded capacity, growth and development would be constrained

• Contrary to the adopted land use policies

• Conflict with goals of elected officials in the region

• Pima County Wastewater Management entered into partnership agreements with the Developers to implement wastewater treatment capacity

• Partnerships are mutually satisfactory to meet the needs of all stakeholders

Avra Valley WWTF ExpansionAvra Valley WWTF Expansion

LocationLocation

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Location and Service AreaLocation and Service Area

IntroductionIntroduction

• Avra Valley WWTF was approaching capacity of 1.2 mgd in April 2006– Current population served: 13,000 (1.1 mgd)– Projected population in 2025: 61,000 (5.2 mgd)

IntroductionIntroduction

Developments in the Avra Valley service area

Años de OroBranding Iron IICaddis Haley EstatesCamino Verde EstatesCamino Verde VillagesCopper CrestDesert MeadowsDesert Meadows WestDiablo Village EstatesEagle Point EstatesGolden GateGrant Industrial Sites

Años de OroBranding Iron IICaddis Haley EstatesCamino Verde EstatesCamino Verde VillagesCopper CrestDesert MeadowsDesert Meadows WestDiablo Village EstatesEagle Point EstatesGolden GateGrant Industrial Sites

Sonoran Ranch EstatesSonoran Ranch VillagesStar ValleyStarr Ridge Tierra BonitaTucson EstatesTucson Mountain RanchTucson Mountain SanctuaryTucson Mountain VillageWestview Pointe Winchester Ranch

Sonoran Ranch EstatesSonoran Ranch VillagesStar ValleyStarr Ridge Tierra BonitaTucson EstatesTucson Mountain RanchTucson Mountain SanctuaryTucson Mountain VillageWestview Pointe Winchester Ranch

Millstone Industrial DistrictMountain Village Estates No. IIOld Tucson Estates Pascua PuebloPascua Yaqui CasinoPomegranate FarmsSan Joaquin OesteSan Joaquin Ranch EstatesShadow Mountain RanchSierra VillasSierra Villas NorthSnyder Hill Estates

Millstone Industrial DistrictMountain Village Estates No. IIOld Tucson Estates Pascua PuebloPascua Yaqui CasinoPomegranate FarmsSan Joaquin OesteSan Joaquin Ranch EstatesShadow Mountain RanchSierra VillasSierra Villas NorthSnyder Hill Estates

Existing dwelling units 7,732Under development 2,218Proposed 8,603

Total equivalent dwelling units 18,553

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IntroductionIntroduction

• Planning activities:– Interim Expansion Plan: Improvements to

increase capacity to 2.2 mgd

• Currently out to bid

• Completion date late 2006

– Long-range Plan: New 4.0 mgd expansion,existing 2.2 mgd facility taken off-line and rehabilitated for final capacity of 5.6 mgd

• Design and Construction-Manager-at-Risk contracts currently in Procurement

• Expected completion date January 2008

Interim Plan – 1.2 to 2.2 MGD ExpansionInterim Plan – 1.2 to 2.2 MGD Expansion

• Avra Valley Sewer Facilities Development Agreement provides funding

• Two-phase expansion planned initially

• Adding participants to agreement will allow:– Consolidation of two phases into one– Completion of Interim Capacity 2.2 MGD Expansion

to address:• Short-term need to increase capacity

• ADEQ permit requirements

– Plant effluent quality concerns before completion of Interim Plan

Interim Plan – 1.2 to 2.2 MGD ExpansionInterim Plan – 1.2 to 2.2 MGD Expansion

Existing Site PlanExisting Site Plan

Treatment process –Detail on next slide

PercolationPonds

Sludge Holding Tanks

Effluent Storage Basin

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Interim Plan – 1.2 to 2.2 MGD ExpansionInterim Plan – 1.2 to 2.2 MGD Expansion

Existing Process Site Plan

Headworks

Equalization Basin

Clarifiers

Oxidation ditch

Overflow Basins

Interim Plan – 1.2 to 2.2 MGD ExpansionInterim Plan – 1.2 to 2.2 MGD Expansion

Mixed Liquor Recycle Pumps (2)

Channel

Floating BrushAerators (4)

Anoxic BasinDiversion Structure

Self-cleaning Bar Screen

Future Growth NeedsFuture Growth Needs

Avra Valley WWTF – Capacity versus Demand

-

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

Sep-05

Dec-05

Mar-06

Jun-0

6

Sep-06

Dec-06

Mar-07

Jun-0

7

Sep-07

Dec-07

Mar-08

Jun-0

8

Sep-08

Dec-08

Mar-09

Jun-0

9

Sep-09

Dec-09

Mar-10

Jun-1

0

Sep-10

Dec-10

Mar-11

Jun-1

1

Sep-11

Dec-11

Mar-12

Jun-1

2

Oct-12

Jan-1

3

Apr-13

Jul-1

3

Oct-13

Jan-1

4

Apr-14

Jul-1

4

Oct-14

Jan-1

5

Apr-15

Jul-1

5

Oct-15

Date

Gal

lons

per

Day

2.2 MGD Interim Expansion

4.0 MGD Expansionand take 2.2 MGD off-line

Rehabilitate old facility to add 1.6 MGD

“Just In Time”

Projected Demand

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Proposed 4.0 MGD ExpansionProposed 4.0 MGD Expansion

• Concurrent design and construction of 2.2 mgd and 4.0 mgd Biological Nutrient Removal Oxidation Ditch (BNROD) expansions

• 4.0 mgd expansion to be completed in January 2008

• Upon completion, existing facility will be idled for future rehabilitation and capacity expansion

Proposed 4.0 MGD ExpansionProposed 4.0 MGD Expansion

Proposed 4.0 MGD Expansion

2.0 mgd BNRODs Clarifiers (2)

RAS/WAS Pump Station

Equalization

Headworks

Lift Station

Solids Handling

Tertiary Filtration & Disinfection

Effluent Storage

1.2 mgd BNROD

Corona de Tucson WWTF ExpansionCorona de Tucson WWTF Expansion

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LocationLocation

Location and Service AreaLocation and Service Area

Current Corona de Tucson WWTF Service Area

BackgroundBackground

• Existing Facility:– Aerated pond with soil aquifer treatment and

evaporation– Current capacity: 300,000 gpd– Current population served: ~2000– Projected population by Dec. 31, 2006

(based on developer projections): ~5000– Projected population in 2025: ~26,900

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BackgroundBackground

Existing Site Plan

EvaporationPond

Soil AquiferTreatment BasinsAeration

Basins

Projected Capacity DemandProjected Capacity Demand

Developments in the Corona de Tucson service area

Existing dwelling units 643Under development 4,276

Santa Rita RanchSanta Rita EstatesSanta Rita Ranch II & III & Block 1Oasis Santa RitaNew Tucson Units 2, 4, 5, 7-10Sycamore Canyon Blocks 1-18 & Lots 1-485

Proposed 5,272The Bells of Santa Rita (Phase I & II)MirasolSanta Rita FoothillsMt. FaganOther Developers

Total equivalent dwelling units 10,191

PlanningPlanning

• Planned improvements

• 1.3 mgd capacity will serve projected demand until 2012

4th quarter, 2006300,000 gpd to 1.3 mgd Expansion

CompleteDescription

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PlanningPlanning

300,000 gpd to 1.3 mgd Expansion

Projected Demand

100,000 to300,000 gpdExpansion

“Just In Time”

300,000 gpd to 1.3 mgd Expansion300,000 gpd to 1.3 mgd Expansion

• Two 500,000 gpd oxidation ditches and recharge basins will be added with provisions for improvement to Class A+ reclaimed water

• Funding– Funded under a Sewer Facilities Development

Agreement between Santa Rita Sewer Association (S.R.S.A., L.L.C.), and Pima County

• Schedule– Construction start: March 2006

– Construction completion: December 2006

Future Site PlanFuture Site Plan

New RechargeBasins

Combined OxidationDitches / Clarifiers

New Mechanical/Electrical and Admin. Complex

New DiversionStructure

18” Effluent

21” Sewer

Combined Construction Plan

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Small Town Sewer WoesSmall Town Sewer Woes

Small Town ChallengesSmall Town Challenges

• Sahuarita is a small incorporated town (1994) 15 miles south of Tucson (population 15,000)

• Located in the Tucson Basin (not part of the Pima County Sewer System)

• Limited funding and small CIP staff

• Permitted 250,000 gpd WWTP

• November 2005, treating 319,000 gpd

• July 2006, treating 419,000

• Construction of a 250,000 gpd expansion is complete, but not permitted

Small Town ChallengesSmall Town Challenges

• 500,000 gpd total capacity with the new expansion

• Could exceed capacity by the end of this year

• Trouble with regulatory compliance

• Little time left for additional capacity expansion

• Current “moratorium” on new home construction

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“Just In Time” Developer Delivery“Just In Time” Developer Delivery

Ground RulesGround Rules

• Developers to follow County project delivery methodology and technical standards

• Developers to finance construction with repayment in the form of connection fee credits recovered commensurate with new home construction (12-18 months)

• Design to be approved by Pima County Wastewater Management (PCWMD)

• Project Management to be joint effort between Developers and PCWMD

Avra Valley (1.2 to 2.2 mgd)Avra Valley (1.2 to 2.2 mgd)Pima County Expenses

Design $ 250,000

CM / Inspection $ 99,782

Direct/indirect completion charges $ 145,000

$ 494,782

Developer Expenses

Contract Construction $3,264,305

CM Charges $ 250,000

Direct Charges $ 50,000

$3,564,305

Total Project Costs $4,059,087

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Avra Valley (1.2 to 2.2 mgd)Avra Valley (1.2 to 2.2 mgd)

• Cost/Gal $ 4.06

• Average House Connection Fee $4,050.24

• Developer break even 880 units

• Developer break even 18 months

• This contract provides for credit against connection fees

Corona de Tucson (.3 to 1.3 mgd)Corona de Tucson (.3 to 1.3 mgd)

Pima County Expenses (Direct)

CM/Inspection over-site $ 100,000

WMD Direct/indirect completion charges $ 100,000

$ 200,000

Developer Costs

Initial Cost Estimate 1.0 mgd (incl design) $6,000,000

System Enhancements (Estimate) $ 500,000

$6,500,000

Total Project Costs $6,700,000

Corona de Tucson (.3 to 1.3 mgd)Corona de Tucson (.3 to 1.3 mgd)

• Cost/Gal $ 6.70

• Average House Connection Fee $4,050.24

• Developer break even 1,605 units

• Developer break even 18 – 24 mo

• This contract provides for cash reimbursement to the Developers

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SummarySummary

• Capacity availability tied to success of expansion schedule with no favoritism of one developer over another

• Developers can control their own destiny in regards to capacity timing

• Capacity letters sufficient for Developer’s project financing

• Regulatory compliance in regards to capacity is met (No new capacity, no system connection)

• Alternative source of project funding

Update

Where will development go next?

Pygmy owl delistedon May 15, 2006