Selection of sludge treatment
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Abstract:1,Centrifugal dehydratorThe decanter centrifugal dewatering machine is mainly composed of a rotating drum and a spiral pusher with a hollow shaft. After the sludge is fed into the drum from the hollow shaft, it is immediately thrown away under the cen…
The decanter centrifugal dewatering machine is mainly composed of a rotating drum and a spiral pusher with a hollow shaft. After the sludge is fed into the drum from the hollow shaft, it is immediately thrown away under the centrifugal force of thousands of times greater than the gravity generated by high-speed rotation. Inside the drum cavity. The specific gravity of the sludge particles is relatively large, so the centrifugal force generated is also large, and it is thrown on the inner wall of the rotating hub to form a solid layer; the water density is small and the centrifugal force is small, and a liquid layer is generated only inside the solid layer. The sludge in the solid layer is conveyed to the cone end of the drum under the slow push of the screw feeder, and is continuously discharged through the mud outlet of the drum. The liquid overflows from the water outlet to the outside of the drum, and is collected and discharged for dehydration. machine.
The characteristics of the decanter centrifugal dewatering machine: small footprint, simple operation, continuous operation, high degree of automation, less pollution to the working environment, less labor intensity of the operator; decanter centrifugal dehydration machine is more affected by the fluctuation of sludge load Small, due to the large centrifugal force, the sludge pretreatment (flocculation) is not high. Therefore, a flocculant with a smaller molecular weight can be selected with a small amount and a low operating cost.
The dewatering technology of centrifugal dewatering machine has made great progress in recent years, especially some foreign advanced technologies, such as the spiral centrifugal dewatering machine produced by Sweden's AlfaLayal Company, Germany's FlOwttwey Company, USA's Sharples Company, Japan's Ishikawa Harima Company, The mud cake has a solids content of more than 30%, continuous operation, stable and reliable, the slurry can be concentrated without high degree of automation, and the operation is carried out in a completely closed environment, without any sludge and sewage around the dehydrator. Existence and no foul odor can greatly improve the working environment of the operators, so it is favored by the industry and has great market potential.
2. Belt filter press dehydrator
The belt filter press dehydrator is composed of two upper and lower tensioned filter belts carrying the sludge layer, passing through a series of regularly arranged rollers in an S shape, and relying on the tension of the filter belt to form the squeezing layer and the sludge layer. Shear force, continuous operation, squeezes out the water in the sludge layer, thereby achieving sludge dehydration.
The belt filter press dehydrator is greatly affected by the sludge load fluctuation. When the sludge load is large, the sludge will overflow from both sides of the filter belt and contaminate the site. After the filter belt in operation is transferred to the lower part, a large amount of water will be backwashed. The sludge adhered to the filter belt does not block the pores of the filter belt. Because the belt filter press dehydrator is an open work, it has a greater pollution to the working environment and consumes a larger amount of water. The operation is tedious, the filter belt is often deviated, and the filter belt is worn out during the operation. It is necessary to adjust and replace the new filter belt in time. Therefore, the management control is relatively complicated and the quality of the operating operators is high. Sludge pretreatment (flocculation) requires high requirements, high molecular weight flocculants and large amounts are used, so it is expensive and costly.
3. Plate and frame filter press dehydrator
The plate and frame filter press is used to squeeze out the water in the sludge through the filter cloth to achieve the purpose of dehydration. It is mainly composed of a concave filter plate, a frame, an automatic-pneumatic closed system side plate suspension system, a filter plate vibration system, an air compression device, a filter cloth high-pressure washing device, and a photoelectric protection device on the side of the fuselage. When selecting equipment, the following aspects should be considered:
(1) Requirements for the solid content of mud cake. Compared with other types of dehydrators, the plate-and-frame filter presses have a high solid content of mud cakes, which can reach 65%. If considering the factors of reducing the land occupation of sludge stacking, plate-and-frame filter presses It should be a ^ scheme.
(2) Material of filter plate and filter cloth. Requires corrosion resistance and a certain tensile and compressive strength.
(3) How to move the filter plate. The requirements can be completed fully automatically or semi-automatically by a hydraulic-pneumatic device to reduce the labor intensity of the operator.
(4) Operators have high labor intensity, large floor area, large site pollution, large loss of filter cloth and filter plate, and low production efficiency.