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Honorable Chairman and <br />Board of County Commissioners <br />9/16/91 <br />Page 22 <br />The expected performance of belt filter presses is dependent upon many <br />factors: type of sludge. quality of conditioning, pressure of rollers. <br />number of rollers, etc. However, with a feed concentration of 0.75 to 1.5 <br />percent of waste activated sludge, a cake with a solids concentration of 12 <br />to 18 percent can be expected. The specifications will require the belt <br />filter presses to achieve a minimum of 12 percent solids concentration and a <br />monthly average of 15 percent solids concentration. Polymer addition is <br />required at a rate of a minimum five to ten pounds of dry polymer per ton of <br />dry feed solids. Therefore. an overall solids capture of 95 percent is <br />expected. <br />Table 5 is a summary of the design criteria of the belt filter presses. The <br />dewatering building includes such items as the belt filter presses. polymer <br />system. cake conveyer system, and other necessary appurtenances. Also <br />included with the dewatering building design are two ram -eject type trailers <br />to haul the dewatered sludge to the landfill. <br />Class 1 reliability criteria require that a sufficient number of presses be <br />installed to enable the design sludge flow to be dewatered with the largest <br />capacity unit out of service. However, if the equipment is sized on Tess <br />than 24-hour per day operation, extension of normal working hours can be used <br />to make up lost capacity. Therefore, a full standby belt press will not be <br />installed. Also, no dewatered sludge storage will be needed. If sludge <br />cannot be hauled away, sludge inventories will temporarily be increased at <br />the wastewater treatment plants and the septage will be stored in the septage <br />holding tank. <br />M.VRB2/5 <br />