Just In Time Treatment Capacity

Transcription

1 Just In Time Treatment Capacity Developers and Utilities Can Partner June 2006 Pima 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 Background 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 1

2 Background Projected Growth Before 1999 Background Pygmy Owl Habitat Projected Growth Before 1999 Background Pygmy Owl Habitat Redirected Growth After 1999 Projected Growth Before

3 Background 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 Expansion Location 3

4 Location and Service Area Introduction 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) Introduction Developments in the Avra Valley service area Años de Oro Branding Iron II Caddis Haley Estates Camino Verde Estates Camino Verde Villages Copper Crest Desert Meadows Desert Meadows West Diablo Village Estates Eagle Point Estates Golden Gate Grant Industrial Sites Millstone Industrial District Mountain Village Estates No. II Old Tucson Estates Pascua Pueblo Pascua Yaqui Casino Pomegranate Farms San Joaquin Oeste San Joaquin Ranch Estates Shadow Mountain Ranch Sierra Villas Sierra Villas North Snyder Hill Estates Sonoran Ranch Estates Sonoran Ranch Villages Star Valley Starr Ridge Tierra Bonita Tucson Estates Tucson Mountain Ranch Tucson Mountain Sanctuary Tucson Mountain Village Westview Pointe Winchester Ranch Existing dwelling units 7,732 Under development 2,218 Proposed 8,603 Total equivalent dwelling units 18,553 4

5 Introduction 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 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 Expansion Sludge Holding Tanks Percolation Ponds Effluent Storage Basin Treatment process Detail on next slide Existing Site Plan 5

6 Interim Plan 1.2 to 2.2 MGD Expansion Oxidation ditch Clarifiers Headworks Equalization Basin Overflow Basins Existing Process Site Plan Interim Plan 1.2 to 2.2 MGD Expansion Floating Brush Aerators (4) Mixed Liquor Recycle Pumps (2) Channel Diversion Structure Anoxic Basin Self-cleaning Bar Screen Future Growth Needs Avra Valley WWTF Capacity versus Demand 6,000,000 Just In Time 5,000,000 Projected Demand 4,000,000 Gallons per Day 3,000,000 2,000,000 1,000, MGD Expansion and take 2.2 MGD off-line Rehabilitate old facility to add 1.6 MGD - Sep-05 Dec-05 Mar-06 Jun-06 Sep-06 Dec-06 Mar-07 Jun-07 Sep-07 Dec MGD Interim Expansion Mar-08 Jun-08 Sep-08 Dec-08 Mar-09 Jun-09 Sep-09 Dec-09 Mar-10 Jun-10 Sep-10 Dec-10 Date Mar-11 Jun-11 Sep-11 Dec-11 Mar-12 Jun-12 Oct-12 Jan-13 Apr-13 Jul-13 Oct-13 Jan-14 Apr-14 Jul-14 Oct-14 Jan-15 Apr-15 Jul-15 Oct-15 6

7 Proposed 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 Expansion 1.2 mgd BNROD Effluent Storage Tertiary Filtration & Disinfection Solids Handling Headworks Lift Station RAS/WAS Pump Station Equalization 2.0 mgd BNRODs Clarifiers (2) Proposed 4.0 MGD Expansion Corona de Tucson WWTF Expansion 7

8 Location Location and Service Area Current Corona de Tucson WWTF Service Area Background 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 8

9 Background Evaporation Pond Aeration Basins Soil Aquifer Treatment Basins Existing Site Plan Projected Capacity Demand Developments in the Corona de Tucson service area Existing dwelling units 643 Under development 4,276 Santa Rita Ranch Santa Rita Estates Santa Rita Ranch II & III & Block 1 Oasis Santa Rita New Tucson Units 2, 4, 5, 7-10 Sycamore Canyon Blocks 1-18 & Lots Proposed 5,272 The Bells of Santa Rita (Phase I & II) Mirasol Santa Rita Foothills Mt. Fagan Other Developers Total equivalent dwelling units 10,191 Planning Planned improvements Description 300,000 gpd to 1.3 mgd Expansion Complete 4 th quarter, mgd capacity will serve projected demand until

10 Planning Just In Time 100,000 to 300,000 gpd Expansion 300,000 gpd to 1.3 mgd Expansion Projected Demand 300,000 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 Plan Combined Construction Plan New Recharge Basins Combined Oxidation Ditches / Clarifiers New Mechanical/ Electrical and Admin. Complex 18 Effluent New Diversion Structure 21 Sewer 10

11 Small Town Sewer Woes Small 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 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 11

12 Just In Time Developer Delivery Ground 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) 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 12

13 Avra Valley (1.2 to 2.2 mgd) Cost/Gal $ 4.06 Average House Connection Fee $4, 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) 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) Cost/Gal $ 6.70 Average House Connection Fee $4, Developer break even 1,605 units Developer break even mo This contract provides for cash reimbursement to the Developers 13

14 Summary 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 Pygmy owl delisted on May 15, 2006 Where will development go next? 14