The City of Lynnwood. Centrifuge or Screw Press? To Incinerate or not to Incinerate a Best Practice Review

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1 The City of Lynnwood Centrifuge or Screw Press? To Incinerate or not to Incinerate a Best Practice Review

2 Agenda The City of Lynnwood Lynnwood Wastewater Treatment Evaluation Process O&M Cost Comparison Summary & Questions

3 The City of Lynnwood Population over 35,000 Fourth largest City in Snohomish County and twentyninth largest in Washington State. The city is a mix of urban, suburban, small city, crossroads, and bedroom community 16 miles north of Seattle the city covers 7.8 square miles Scriber Lake, Hall Lake and Swamp Creek all run through Lynnwood Central Washington University and Edmonds Community College have locations in Lynnwood

4 Lynnwood Wastewater Treatment Lynnwood provides sewer service to approximately 35,000 people with: 104 miles of sewer mains 6 lift stations 1 Wastewater Treatment Plant (WWTP) The Lynnwood WWTP treats sewage for 90% of Lynnwood plus a portion of Edmonds north of Olympic View Drive The facility has a rated capacity of 7.4 MGD and an average flow of 5 MGD. Peak flow has reached 20 MGD during severe storm weather The 36 diameter outfall into Browns Bay goes out approximately 1000 feet and is 120 feet deep 8,000-10,000 pounds of dried solids are incinerated daily

5 Lynnwood WWTP Biosolids Handling Challenges Dewatering The existing Centrifuges at end of life and require significant capital investment High risk of failure and cost of sludge hauling Funds allocated in CIP for new centrifuges High O&M costs, maintenance burden

6 Lynnwood WWTP Biosolids Handling Challenges Incineration New EPA air quality regulations for wastewater incineration Annual emissions testing High risk of failure and cost of sludge hauling

7 Dewatering Evaluation Process Why screw press? Tour facilities with existing installations Define performance requirements Sludge sampling, signed performance guarantees Evaluation matrix to determine manufacturer

8 Lynnwood Wastewater Treatment Evaluation Process Project team selected 3 screw press manufacturers Project team developed performance specification Each manufacturer signed the performance spec An evaluation matrix was developed by project team in order of City priorities and drivers The manufacturers were scored and the equipment was selected

9 Screw Press Matrix

10 Centrifuge vs Screw Press O&M Cost Comparisons O&M Costs Centrifuge Screw Press O&M $ 26,000 $ 1,000 Energy Use $ 11,000 $ 1,140 Total Annual O&M Costs $ 37,000 $ 2,140 **Ongoing dryer evaluation

11 Incineration vs. Drying Incineration challenges Risk of increasing EPA restrictions Sludge hauling 24/7 operation O&M Costs Rock formation Drying Benefits Fits limited WWTP real estate Reduced Sludge Hauling Risk Natural gas vs. diesel fuel Reduced O&M costs Marketable waste product **Ongoing dryer evaluation

12 Incineration vs. Drying O&M Cost Comparisons O&M Costs Incinerator Dryer Ash/Sludge Hauling $ 50,000 $ 70,000 Staff Overtime Cost $ 6,000 Sand Replacement & Downtime Cost $ 4,000 Emissions Testing (annual) $ 40,000 Annual Incinerator Down Time & Associated Hauling Costs $ 235,000 Dryer Annual Maintenance $ 5,000 Total Annual O&M Costs $ 335,000 $ 75,000 **Ongoing dryer evaluation

13 Project Goals Phase 1 Replace Centrifuge with Screw Press Limit City s risk Stretch CIP funding Replace end of life equipment, energy savings Increase system reliability Reduce annual energy consumption and O&M costs/labor Reduce project management burden on City staff

14 Energy Savings Performance Contracting City gets what they want Reduced burden on City staff Guaranteed maximum price Maximize grant/incentive dollars Leverage CIP funding to optimize cash flow

15 Laying the foundation of partnership Lynnwood selected Trane because Trane partnered with the City to make it the City s project Design Build Construction Lynnwood involved throughout design to shape the project through equipment/consultant selection and driving solutions Guaranteed Maximum Cost and Guaranteed Minimum Savings (known max budget before project starts) City maintains control over the project

16 Questions?