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Honorable Chairman and <br />Board of County Commissioners <br />9/16/91 <br />Page 21 <br />one percent solids concentration up to a 12 percent solids concentration <br />reduces volume by over 90 percent and results in a non-fluid material. This <br />substantial reduction in volume is done primarily to decrease the capital and <br />operating costs of the subsequent sludge disposal process. <br />Two waste activated sludge feed pumps will feed the sludge from the sludge <br />holding tanks to the belt filter presses located in the solids processing <br />building. The pumps are heavy-duty, self -priming, positive displacement. <br />rotary lobe type, each rated at 185 gallons per minute (gpm). <br />The recommended dewatering process units are belt filter presses. This type <br />of mechanical dewatering unit employs an endless moving belt to dewater <br />sludge continuously. The process consists of three basic operational stages: <br />chemical conditioning of the feed sludge by polymer addition, gravity <br />drainage to a non-fluid consistency. and compaction of the partially <br />dewatered sludge. <br />The design loading of the belt filter presses is based upon the maximum <br />monthly solids loading of 21,025 lbs/day. This consists of 19,120 lbs/day of <br />raw waste activated sludge, 1,820 lbs/day of septage and 85 lbs/day of <br />polymer. Assuming a six-day per week and 12 hours per day operation of the <br />belt filter presses, a solids loading rate capacity of 2.044 lbs/hr is <br />required. A typical solids handling capacity of 600 lb/hr/meter is used for <br />design. Therefore. two 2.0 meter belt filter presses will handle the maximum <br />month solids loading. Additional presses may be added, if needed. <br />M. VRB2/5 <br />