2008 Facility Plan Update May 2008

Purpose  Comprehensive Plan through 2033 –Builds on Past Work –Adjust for Changing Conditions  Identify Capacity, Compliance, and Rehabilitation needs –Robert W. Hite Treatment Facility –Biosolids Management Program –Transmission System  Develop Cost-Effective Capital Improvement Program –To meet Future (more stringent) Effluent Quality Requirements –Accommodate Growth  Renewal 2003 Wastewater Utility Plan –Denver Regional Council of Governments (DRCOG)

Updates 2003 Wastewater Utility Plan Defines South Secondary Improvements (PAR 1085) Updates Transmission System InfoWorks Model Updates 2007 Land Use Model Updates Plant GPS-X and Hydraulic Models Includes PELs from Future Effluent Limits Study Updates 2003 Facility Plan & 2002 Service Area Utility Plan, and 2007 Biosolids Study Incorporates North Secondary Improvements (PAR 942) What’s Included in 2008 Update Does not include IS/Support facilities

South Secondary Improvements  Parallel Track –Ammonia Compliance Deadline December 31, 2014 Jan 08 South Secondary Predesign Define South Secondary Needs Jun 07Jul 07 Technical Team Review Develop Alternative Layouts and Costs Aug 07 Begin Facility Plan Feb 07 Complete Facility Plan Mar 08 Complete Predesign Mar 09

Metro District Service Area 615 square miles and includes City and County of Denver and parts of Adams, Arapahoe, and Jefferson counties Six Drainage Basins

Member Municipalities and Special Connectors 20 Member Municipalities and 25 Special Connectors

Metro District Service Area Including Brighton and South Adams

Population and Employment Projections  Projections based on: –Updated Member Municipality & Special Connector information –Current population, employment & boundary information from DRCOG  TAZ Data (Transportation Analysis Zones) –Buildout projections from the Land Use Model  Population – Increase 39% or 1.5% per year thru 2033  Employment – Increase 52% or 2.0% per year thru 2033

Flow and Load Projections  Unit Flow Factors –85 gallons per capita per day –17 gallons per day per employee  Developed Service Area Projections  Adjusted to Determine Primary Influent Flows and Loads –Exclusion of area tributary to a future Box Elder WWTP –Reduction in flow of 5 mgd for the Sand Creek Water Reclamation Facility –Additional loads, such as in-plant and hauled wastes –Increase in BOD loads from DIA

Historic and Projected Primary Influent Flow and Loads

Existing Robert W. Hite Treatment Facility Liquid Stream Capacity  Current max month rated capacity 220 mgd with EPC (~185 mgd Annual Average)  Capacity without EPC 161 mgd Annual Average (Secondary Treatment)  North and South Secondary Expansions required to meet capacity and regulatory requirements  RWHTF AAF capacity needs to be 210 mgd in 2033

Existing Robert W. Hite Treatment Facility Solids Stream Capacity  Improvements to the digesters and high-solids centrifuges are planned during

Existing Transmission System Summary  219 miles of interceptors, 12 miles of force mains and 4 lift stations  Capacity evaluation based on: –Previous modeling from 2002 SAUP –Updated Land Use Model –Updates to existing InfoWorks Model

Phase 5 Beyond 2023 Discharge Permit Requirements Anticipated to Remain Unchanged Through Planning Period 3Minimum dissolved oxygen, mg/L pH range, standard units 0.011Maximum chlorine residual, mg/L 30TSS, mg/L 17CBOD, mg/L – 8.68 – 8.68 – Nitrates (plus nitrites), mg-N/L Daily maximum 7-day average 30-day average – Total ammonia, mg-N/L Daily maximum 7-day average 30-day average Discharge Permit Requirements Anticipated to Change in Phase 2 Phase Phase Parameter Total phosphorus, mg-P/L Phasing Assumption Assumed Range Total nitrogen, mg-N/L Phasing Assumption Assumed Range Phase Parameter Discharge Permit Requirements Anticipated to Change in Phases 4 and 5 Regulatory Assumptions

Improvements and Project Implementation  Transmission System improvements driven by rehabilitation needs and capacity constraints due to growth  RWHTF improvements phased over planning period to meet capacity, regulatory, and rehabilitation needs  Used recently developed Metro District Cost Estimating Guide for consistent and better cost estimates  Recommended improvements “packaged,” according to type, location, and timing –Construction Efficiencies –Save Capital Costs  Goal of the phased program is to continuously meet customer service and regulatory requirements through the end of the planning period

Transmission System Rehabilitation  Inspection Program –Closed-circuit television and surface inspections –CCTV inspection annually on portion of system –CCTV taping of each interceptor every 10 years –Three categories based on degree of degradation  Transmission Division reviews to assess condition  Engineering Department performs second review, further refines the condition, develops a cost estimate and schedule

Transmission System Rehabilitation  CIPP  Slip Lining  Manhole Rehab

Transmission System Capacity Improvements  Transmission System hydraulic modeling –2002 model updated with Sand Creek Basin Wastewater Master Plan –Model updated with revised population, employment, and unit flows –Model runs performed for 2007, 2015, and 2030 –Assumed northeast Service Area flows will continue to RWHTF –Flow data being collected to further refine model calibration in 2008

Metro District Transmission System Capacity Concerns in 2015

Metro District Transmission System Capacity Concerns in 2030

Transmission System Project Implementation Schedule

Basis for RWHTF Recommended Improvements  2003 Facility Plan established basic direction –Five-stage air-activated sludge with BNR –Phasing out the high-purity oxygen system  North Secondary Improvements Project (PAR 942) –CaRRB process to address centrate treatment  Objective is to have similar processes in the North and South Complexes that operate and perform in a comparable fashion

RWHTF Recommended Improvements

RWHTF Project Implementation Schedule

Projected Capital Expenditures $1.86 billion projected $1,528,000,000 – RWHTF $332,000,000 – Transmission System

Questions

RWHTF Buildout Site Plan (230 mgd)