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Nutrient Issues at the Blue Plains WWTP

Nutrient Issues at the Blue Plains WWTP . February 2004. Blue Plains Snapshot. Flow Design Annual Average: 16.2 m 3 /s (370 mgd) Peak: 43.8 m 3 /s (1 bgd) Effluent Limits NH 3 :1.0 mg/l (May 1 to Oct 30) 6.5 mg/l (Nov 1 to April 30 TP: 0.18 mg/l BOD5/TSS: 5/7 mg/l.

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Nutrient Issues at the Blue Plains WWTP

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  1. Nutrient Issues at the Blue Plains WWTP February 2004

  2. Blue Plains Snapshot • Flow • Design Annual Average: 16.2 m3/s (370 mgd) • Peak: 43.8 m3/s (1 bgd) • Effluent Limits • NH3:1.0 mg/l (May 1 to Oct 30) 6.5 mg/l (Nov 1 to April 30 • TP: 0.18 mg/l • BOD5/TSS: 5/7 mg/l

  3. Process Flow Diagram FeSO4 FeCl3 Aerated Grit Primary Sediment Secondary AS Nitrification Chlorine Dechlorination Potomac River Pumping Chlorination Filtration

  4. Blue PlainsNitrogen Control Efforts Goal:Reduce controllable loads of nutrients including nitrogen by 40% from the 1985 levels by the year 2000, and maintain those levels into the future Status: Nitrogen loads from Blue Plains declined by 7 million pounds per year from 1995 to 2003. The load was reduced by 49%, surpassing the Chesapeake Bay goal. This significant reduction was achieved through the use of Biological Nutrient Removal (BNR) Technology.

  5. Denitrification Process Selection • Lowest cost alternative for nitrogen removal - 1990 study • Bench testing showed promise • Low capital cost offsets operating costs • Process considered experimental - especially at this scale - Conduct pilot

  6. Denitrification Process Selection • Use excess capacity available in nitrification process • Conduct full plant study • Monitor results on both sides. • TN Goal 7.5 mg/L yearly average: • Winter: 8.58 mg/l • Summer: 5.55 mg/l

  7. Nitrification Facilities Lime Sedimentation Basins Secondary Effluent To Multimedia Reactors RAS WAS

  8. Denitrification Process Lime Methanol Sedimentation Basins Secondary Effluent To Multimedia Reactors RAS WAS

  9. IMA Shares at Blue Plains

  10. Nutrient Reduction Options @ Blue Plains • Meeting Maryland and/or Virginia’s load allocations would require: • Additional treatment for a portion of the flow, as needed (Blended Effluent) • Significant capital expenditures • Meeting ALL BP users’ needs – under a regulatory program -- would require: • Plant-wide facilities upgrade • Major capital expenditures • Costs will depend on the level of nutrient reduction (Tier) that will be needed

  11. Nutrient Reduction Options at Blue Plains Voluntary Program Estimated Costs (*) All WWTPs at their year 2000 levels (#) Blue Plains is at 7.5 mg/lit TN & 0.18 mg/lit TP; budget is for facilities needed to accommodate new digester effluent [$] Under NPDES permit requirement, the cost would be 30-50% higher

  12. Other Capital Costs Facing DCWASA • Ongoing 10 year Capital program • $1.8 billion • Infrastructure/plant rehabilitation • Technology enhancements supporting operational efficiencies • Proposed CSO Long-Term Control Plan • $1.265 billion over 15-25 years • Enhancement of water quality in tributaries of Chesapeake Bay, notably Anacostia River • Lead Service Replacement Issues • Emerging regulatory/security issues

  13. WASA’s CURRENT POSTURE • Meet all regulatory requirements • Continue strong support of state-by-state determination of methods to meet “caps” • Provide services to jurisdictions to assist in meeting their nutrient goals within Blue Plains capacity • Emphasize that DC’s primary appeal for federal assistance will be directed to the Anacostia CSO issue • Continue strong support of a VOLUNTARY (non-Regulatory) Nutrient Reduction Program

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