WASTEWATER SLUDGE TREATMENT CASE STUDY Metropolitan Sewer District (MSD) Cincinnati, Ohio
by user
Comments
Transcript
WASTEWATER SLUDGE TREATMENT CASE STUDY Metropolitan Sewer District (MSD) Cincinnati, Ohio
WASTEWATER SLUDGE TREATMENT CASE STUDY Metropolitan Sewer District (MSD) Cincinnati, Ohio Situation The Metropolitan Sewer District (MSD) of Greater Cincinnati, Ohio is a 90 mgd primary treatment, 55 mgd activated sludge treatment plant. Solids processing includes gravity thickening of primary sludge, dissolved air flotation, thickening of secondary sludge, holding tank storage, belt filter press dewatering and pumping of cake to the old outdated multiple hearth incinerator. Solution After an exhaustive feasibility study, MSD and the consultant, Black & Veatch, selected the ODI Hot Windbox HTFB ( high temperature fluid bed) to replace its existing aging © ONDEO Degremont, Inc. - October 2001 multiple hearth. The ODI incinerator was determined to be the most economic and environmental solution. The system was commissioned in June 2000. It is readily adapted to non-continuous operation and is easy to operate and maintain. The unit has met performance targets since its first few days of operation. Air emission rates are substantially lower than permit requirements, and there is no visible plume. System Description The unit is the largest municipal Hot Windbox HTFB built in the USA to date, with a design capacity of 72 dry ton per day. It is a 24 ft ID freeboard, equipped with a refractory arch distributor to minimize auxiliary fuel consumption. The system includes a heat recovery system with two heat exchangers, a quench pre-cooler and a venturi scrubber, which is followed by a cooling tray tower. Contract Type ONDEO Degremont, Inc. was contracted for the supply of the HTFB system, start-up, operator training and commissioning. Process Flow Diagram Compressed Air Continuous Emissions Monitoring System Exhaust Gas Duct High Pressure Water Pump Sand Storage Service Water Stack Sand Heat Exchangers Sludge Feed Primary Secondary Quench Sludge Dewatering Sludge Feed Pump Tray Scrubber Purge Air Blower Fluidizing Air Blower Auxiliary Fuel Oil Preheat Gas Feed Preheat Burner Combustion Air Venturi Scrubber Ash Treatment Preheat Auxiliary Cincinnati Metropolitan Sewer District System Air Emission Performance Air Pollutant PM, Lb/dry ton THC, ppmv as propane CO, ppmv as propane NOx, lb/dry ton SO2, lb/dry ton Opacity % Emission Testing 0.04 0.50 2.28 0.47 0.07 0 Permit Limit 1.30 100 N/A 5.00 7.40 20 P.O. Box 71390 Richmond, VA 23255-1390 • Tel: (804) 756-7600 Fax: (804) 756-7643 • www.ondeo-degremont-usa.com