Recessed Filter

Recessed-plate filter presses are used to remove water from liquid wastewater residuals and produce a non-liquid material referred to as cake. Dewatered cake varies in consistency from that of custard (12 to15 percent solids) to moist soil (20 to 40 percent solids) and is used for the following purposes: To reduce volume, saving money on storage and transportation. To eliminate free liquids prior to landfill disposal. To reduce fuel requirements if the residuals are to be incinerated or further dried. To produce a material with sufficient void space and volatile solids for composting when blended with a bulking agent. To reduce pooling or runoff, which can be a problem when liquid biosolids are land applied. To optimize alkaline stabilization processes. Recessed-plate filter presses are among the oldest types of dewatering devices and can produce the highest cake solids concentration of any mechanical dewatering equipment (Kemp, 1997). They are more commonly used in industrial applications than in municipal wastewater facilities.