First, sludge dewatering machine classification generally medium-sized sewage treatment plants are using mechanical dewatering. Many types of dewatering, dewatering principle can be divided by vacuum filtration, centrifugal filter press dewatering and dehydration three categories. 1. The belt filter press sludge dewatering belt filter press dewatering machine is up and down two tensioned belt clip with sludge filter layer, from a series of S-shaped after a regular arrangement of roll tube, relying on the filter with itself the formation of sludge blanket tension and shear press, the sludge layer capillary water squeezed out, get containing high solid content of the cake, in order to achieve sludge dewatering. 2. The centrifugal sludge dewatering centrifuge dewatering machine is mainly composed of reprinted and spiral conveyor belt consisting of a hollow shaft, after the sludge into the hollow shaft of the drum, the centrifugal force generated by high-speed rotation, immediately flung people rotating hub cavity. Sludge proportion of larger particles, thus centrifugal force is large, being left attached to the rotating hub wall, forming a solid layer; a little water density, the centrifugal force is small, only produce liquid layer on the inside of a solid layer. Solid layer of sludge at a slow push the screw conveyor, is transported to cone reproduced, reprinted around the exit continuously discharged liquid by four weir overflow discharge to reprint, the collection is discharged after dewatering machine. 3. The plate and frame filter press sludge dewatering machine frame by frame filter press is squeezed, the water within the sludge discharged through a filter cloth to achieve the purpose of dehydration. It mainly consists of recessed people type filter plate, frame, automatic - pneumatic suspension system closed system test board, Plates vibration systems, air compression device, high-pressure washing device and a cloth body side protector and the like. Third, sludge dewatering machine features 1. Sludge dewatering machine automatic operation, saving manpower most maintenance management easy. 2. Excellent durability and good mechanical properties, covers an area of ??the province. 3. Apply to a variety of sludge dewatering sludge dehydration, high efficiency, large capacity. 4. Multiple dehydration, strong drainage capacity, sludge cake moisture content is low. 5. Sludge dewatering machine saves energy, less power consumption, low speed, no vibration and no noise. 6. Cloth belt type continuous operation, convenient automatic washing operation. 7. Sludge dewatering filter cloth meandering automatic correction, smooth operation. 8. Cloth installation, exchange easy, maintenance simple. 9. Pharmacy plus less sludge dewatering, low operating cost, reasonable price. Fourth, use 1, 2 industrial wastewater sludge coagulation and sedimentation, the excess activated sludge wastewater 3, urban sewage treatment sludge excess 4, 5 community sewage sludge, water purification plant sludge dosing agglutination 6, disposal of surplus fertilizer sludge 7, factory production process of the solid-liquid separation