Salida Sanitary District
6200 Pirrone Road
The Belt Filter Press

Biosolids are a biproduct of the wastewater treatment process. Periodically a portion of the biomass in the ICEAS tanks needs to be removed to control the concentration. This excess biomass is pumped to an aerobic digester. The digester degrades the organic material in the biomass so that it will be suitable for land disposal. After the digestion process the biosolids must be dewatered and then dried. The "Belt Filter Press" is used to remove this excess water. The water removed at the belt press is returned to the beginning of the treatment the plant.

This pictures shows the first stage of the belt press. The liquid biosolids are pumped to the belt filter press and a small dose of liquid polymer is added. The polymer causes the very small biosolids particles in the mixture to cling together forming a flock. Once the water and floculated biosolids flow onto the belt, the water drains through the belt and the solids are trapped on the surface. As the belt moves the sludge towards the end a series of stationary plows turn the mixture over and over allowing more water to drain. At the end of the upper belt the partially dewatered solids fall onto a lower belt for the next stage of dewatering.

At the second stage of the belt press two middle belts sandwich the wet solids applying pressure to squeeze out more excess water. At the end of the second belt solids fall into a stainless steel hopper and a screw conveyor moves them to the truck.

The Freightliner sludge truck is used to haul the dewatered sludge into the solar driers.

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