Pre-Program Work. Omaha CSO Control Program. Agenda. City has worked on addressing CSOs for many years

Transcription

1 Omaha CSO Control Program 2008 IWPCA Conference Session 3C- Collection Systems CSO Program Management Approach Agenda Pre-Program Work Summary of Program Approach Steps One through Four Refinement Period Key Success Factors Tom Heinemann, CH2M HILL Pre-Program Work City has worked on addressing CSOs for many years Sewer Separation Projects underway since 1990 Mechanical Bar Screens installed for three CSOs Stormwater detention facilities constructed throughout area System-wide model developed since 2004 City has worked on addressing CSOs for many years Flow data collected to support the model Nine Minimum Controls Plan completed and implemented Elements of the preliminary LTCP developed Overflow Statistics for Representative Year (Existing) Missouri River Watershed Papillion Creek Watershed Total System Number of CSO Events Annual CSO Volume (MG) 2, ,429 Total Wet Weather Volume NA 7,243 1

2 September 16, 2005 Letter Required the City to: Submit a Substantively Complete LTCP by October 2007 Submit a Final LTCP by October 2009 Complete construction of LTCP controls by City Selected CSO Program Manager in February 2006 CH2M HILL/HDR/Lamp Rynearson responsible for: Coordinating a comprehensive LTCP Providing computer modeling Conducting accelerated study of Burt-Izard Basin Serving as regulatory lead Managing nine other consultant teams City Divided Combined Sewer System into 10 Basins 10 basins: 6 Complex / 4 Less Complex Missouri River Watershed Bridge Street Minne Lusa Burt-Izard Leavenworth South Interceptor Ohern/Monroe Papillion Creek Watershed Cole Creek Papillion Creek North Saddle Creek Papillion Creek South City Selected Basin Consultants PMT prepared a detailed RFP PMT participated but did not vote Complex Basin Consultants: Black & Veatch (Minne Lusa) HDR (Burt Izard & South Interceptor) Wade Trim (Leavenworth) CDM (Ohern/Monroe) Olsson Associates (Saddle Creek) City Selected Basin Consultants, cont. Less Complex Basin Consultants: HWS (Bridge Street) CDM (Cole Creek) EGA (Papillion Creek North) Black & Veatch (Papillion Creek South) A Quick & Consistent Start Was Essential Scopes of Work for Basin Types Scoping Session (July 2006) Consistent List of Tech Memos Basin Packets Program Management Plan Chartering Sessions PMT (April 2006) and Basin Consultants (September 2006) 2

3 Develop SC LTCP in Four Steps Summary of Program Approach Appropriate Technologies STEP 1 Screen CSO Control Technologies (December 2006) Fundamental Projects SC LTCP with Implementation Plan (October 2007) STEP 4 Develop Systemwide Plan (August 2007) STEP 2 Evaluate Basin (May 2007) STEP 3 Evaluate Watershed (June 2007) Costs vs. CSO Reduction for Watersheds Cost Effective Guidance/Tools Provided by PMT Detailed Protocols 1 Program Overview 2 Data and Information Collection & Coordination 3 System Characterization 4 Development & Evaluation 5 InfoNet Database Management Cost Estimating Tool and Reference Document Sewer Separation Guidance Decision Tool Pollutants of Concern Guidance/Tools Provided by PMT Public Participation Process Web Portal & FTP Site Calibrated InfoWorks Model Baseline Hydrographs for the Representative Year Step One: Screen CSO Control Technologies Screen CSO Control Technologies Fact sheets provided by PMT for 29 CSO control technologies Sewer system modifications Flow reduction Storage Satellite treatment PMT provided screening criteria CSO volume reduction, control of pollutants of concern, site suitability, plus six others Basin Consultants screened the technologies for suitability & fatal flaws for each CSO outfall 3

4 Evaluate Basin Step Two: Evaluate Basin PMT provided additional detail on the evaluation approach BCs combined viable control technologies into Basin PMT developed cross-basin alternatives Evaluations included both costs and non-monetary criteria; B/C ratios were developed. CSO Control Categories Sewer separation Full separation Public separation Storage and treatment Below-ground tanks Deep tunnels High-rate treatment Retention Treatment Basins (RTBs) Ballasted Flocculation/Sedimentation Key Concepts Existing Conditions Combined sewer system (CSS) in 2002 Baseline Conditions CSS following construction of Baseline Improvements Baseline Hydrographs CSO flow rates vs. time during Representative Year Control Levels 1, 2, 3 and 4 Level 1 9 overflows -- Level 3 1 overflow Level 2 4 overflows -- Level 4 0 overflows Benefit/Cost (B/C) ratio: Total Benefit Score from Decision Tool divided by normalized present worth cost Increasing Volume, MG Control of Combined Sewage Volume Total Existing Volume of Combined Sewage Volume Controlled at Control Level Volume Controlled, Baseline Volume Controlled, Existing Basic Assumptions for Evaluating CSO Controls Dewater storage tanks & tunnels within 72 hours Pollutant of concern: E coli (126 per 100 ml) Controls are based on precipitation in Representative Year (1969) Overflow statistics are based on calibrated InfoWorks Model 4

5 Cross Basin Alternative 3 Tunnels along Missouri River Feet Deep Feet in Diameter Treatment at the Missouri River Treatment Plant Public Stakeholders Participated in the Evaluations Public Stakeholders: Community Basin Panel (CBP) and Basin Advisory Panels (BAP) 3 Stakeholder Workshops - Fall of 2006 Decision Criteria Identified by CBP & BAP members CBP assigned initial weights (levels of importance) to the criteria Each BAP customized the weights BCs used the weights in the Decision Tool Stakeholder Workshops CBP Non-Monetary Criteria Weights Water Quality Improvement 16 Reduction of Combined Sewer Back-Ups into Basements 19 Reduction of Street Flooding 11 Minimizing Community Disruptions 13 Simplicity (Reliability) of Solutions 6 Opportunities for Infrastructure/Utility Improvements 13 Compatibility with Community 11 Opportunities for Community Enhancements 12 BAP Customized Weights Benefit/Cost Example $130 Total Benefit Score $ $65 $ Cost ($ Million) Benefit/Cost Ratio Alt. 1 Alt. 2 Alt. 3 Alt. 4 5

6 Burt-Izard Basin -- 85% Volume Capture Benefits and Costs Other Key Activities Monthly BC Progress Meetings Technical Workshops with BCs Monthly Big Picture Meetings Regular Meetings with NDEQ & EPA Other Key Activities, cont. Consent Order Negotiations with NDEQ CSO Monitoring Program with USGS CSO Week! BC Amendments for Field Work Step Three: Evaluate Watershed Development and Selection of Watershed BCs evaluated In-Basin BCs & PMT evaluated Cross-Basin City & PMT: Compiled the evaluations Developed and evaluated Watershed for MR Watershed Selected the to implement (MR & PC Watersheds) Step Four: Develop Systemwide Plan 6

7 Summary of LTCP Projects Deep Tunnel: 12.5 feet in diameter by 5.8 miles long 170 feet deep 6 Drop Shaft Complexes Retention Treatment Basins: 114 mgd at Missouri River WWTP 21 mgd at CSO mgd at CSO 205 Summary of LTCP Projects, cont. Sewer Separation (MR Watershed): Bridge Street, Burt-Izard, Minne Lusa, Ohern/Monroe, South Interceptor Basins Eliminate CSOs 103, 104, 120, 113, 116 Stormwater Tunnel in Minne Lusa Basin (17 feet diameter x 1.4 miles long) Sewer Separation (PC Watershed): Cole Creek, Papillion Creek North, Papillion Creek South Basins Eliminate CSOs 206, 207, 208, 209, 210,211, 212 Summary of LTCP Projects, cont. Other Projects: Industrial Lift Station and Force Main Missouri River WWTP Improvements South Interceptor Force Main Storage tanks in Cole Creek Basin (0.91 MG total volume) In-line storage at CSO 201 (0.1 MG) Cost of CSO Control Increases with Volume Captured Cost Knee of the Curve 85%) Floatables control for untreated overflows Million Gallons of CSO Volume Captured ( Level of Control ) Missouri River Watershed Capital Cost vs. Overflows Papillion Creek Watershed Capital Cost vs. Overflows $1,100,000,000 $450,000,000 Control Level 4 Control Level 4 Control Level 3 $1,050,000,000 Control Level 3 $400,000,000 $1,000,000,000 $950,000,000 Capital Cost $350,000,000 $300,000,000 Capital Cost Control Level 1 Control Level 2 Knee $900,000,000 $850,000,000 Control Level 1 Control Level 2 Knee $250,000,000 $200,000,000 $800,000,000 $150,000, Untreated Overflows Untreated Overflows 7

8 CSO Control Level 2 Was Chosen Exceeds Presumptive Level 4 overflows per year 85% capture of volume 85% capture of load Complies with Water Quality Standards Knee of Curve is apparent Substantively Complete LTCP Submitted on time by October 1, Presented to NDEQ, EPA and public in August. NDEQ/EPA comments have been received and responded to. Refinement Period began immediately. Final LTCP due in October Ongoing Refinement Tasks Refinement Period Tunnel Development & Risk Analysis Retention Treatment Basin Performance Evaluation Program Risk Analysis Sewer Separation Guidance Refinement Cost Tool Verification and Update Green Solutions Update & Recalibrate InfoWorks Model Construction Delivery Plan 18 others Key Success Factors Summary of Key Success Factors Detailed plan was developed early & followed Extensive guidance and tools provided to BCs BCs committed to program success Frequent team communication Close involvement of City staff 8

9 Key Success Factors, cont. Cooperative, trusting approach established with NDEQ & EPA Committed involvement of Public Stakeholders InfoWorks Model started well in advance of the Program CSO Week Discussion & Questions 9