At present, the domestic sludge dewatering device mainly consists of the following forms:
(1) vacuum filtration
Vacuum filter dewatering machine can be continuously produced, can also be automatically controlled, but its ancillary equipment, filter filter cloth to be regular recoil cleaning, the operation process is complex, filter cloth is also easy to plug, dehydrated sludge moisture content is high, generally only for Digestion sludge dewatering, so this project should not be used.
(2) plate and frame filter
Plate and frame pressure filter dewatering effect is good, low prices, after dehydration sludge moisture content is low, labor operation intensity in general, operation and management and affordable. In the process design using plate and frame filter.
(3) belt filter
Belt filter press is currently widely used in sewage dewatering equipment, filter belt can be rotated, continuous operation, sludge treatment effect is stable and so on. But the centrifugal dehydration is expensive, the motor power, high operating costs. Only for large-scale sewage treatment works. Therefore, this project should not be used.
(4) sludge drying pool
Strictly speaking, the sludge drying tank should be called the sludge filter field. Because the sludge produced by the sewage treatment station is large, the area of the sludge drying pool is relatively large, the dehydration efficiency is relatively low, the sludge cleaning is inconvenient, Sludge water content is high, liquefied sludge is not subject to disposal of the surrounding environment is bound to secondary pollution, in the design will not be adopted.
Sludge dewatering equipment
1, plate and frame sludge dewatering machine:
Working principle: in a closed state, through the high-pressure pump into the sludge through the plate and frame of the squeeze, so that the sludge within the sludge through the filter cloth to achieve the purpose of dehydration.
Advantages: low prices, good at dehydration of inorganic sludge, mud cake water content is low.
Disadvantages: easy to plug, the need to use high-pressure pump, not suitable for oily sludge dehydration, it is difficult to achieve continuous automatic operation.
2, belt sludge dewatering machine:
Working principle: from the upper and lower tension of the belt with a layer of mud, from a series of regular arrangement of the roller cylinder, was S-shaped, relying on the tension of the filter itself, the formation of the sludge layer of the press and shear Force, the sludge layer of capillary water squeezed out, in order to achieve sludge dewatering.
Advantages: lower prices, the use of universal, technology is relatively mature.
Disadvantages: easy to plug, need a lot of water cleaning, resulting in secondary pollution.
3, centrifugal sludge dewatering machine: by the reprint and with a hollow shaft of the screw conveyor, the sludge from the hollow shaft into the drum, in the high-speed rotation of the centrifugal force, the production was thrown into the drum cavity. As the proportion is not the same, the formation of solid-liquid separation. The sludge is conveyed continuously to the drum at the conical end of the drum by the screw conveyor. The liquid of the liquid ring layer is discharged from the weir continuously to the drum.
Advantages: large processing capacity.
Disadvantages: power consumption, noise, vibration; maintenance more difficult, not suitable for the proportion of solid-liquid separation.