Analyzing from the typical application of the sludge dewatering process, the whole process can be divided into four stages. The first stage is the sludge concentration, which is mainly to make the sludge initial volume reduction, which can reduce the volume of subsequent processing structures or the capacity of the equipment. In the second stage of the sludge dewatering process, the sludge digestion is mainly carried out to decompose the organic matter in the sludge.
The third part of the sludge dewatering process is called sludge dewatering, which further reduces the amount of sludge. The last stage is the disposal of sludge, mainly using some way to dispose the final sludge. In these four different stages, the produced clear liquid or filter liquor still contains a large amount of pollutants, which need to be sent to the sewage treatment system for treatment.
Combined with the main process described above, the typical sludge dewatering process can realize the " four modernizations" after the treatment of sludge. The so-called four modernizations mainly refers to the reduction, stabilization, harmlessness and resource. For example, before the sludge treatment, the sludge contains more water, and is large and liquid.
After the sludge dewatering process, it can reduce the total volume of the sludge, and gradually transform from the liquid into solid state, which is convenient for transportation and digestion. Moreover, the sludge itself contains more organic matter, it is easy to corrupt and produce a foul smell. After the above steps, the perishable substances can be decomposed and transformed, which is convenient for
transportation and disposal.
In fact, the sludge itself is a resource, so after the sludge dewatering process, it not only can kill bacteria and viruses, but also can further improve the fertilizer efficiency. At present, in the process of sludge thickening, the commonly used treatment processes are gravity concentration, centrifugal thickening and air flotation thickening.