Sludge Stabilization and Conditioning Process

In wastewater treatment system, generated sludge has to undergo proper pretreatment process before it is sent for dewatering or thickening. Therefore both Stabilization and Conditioning are considered as integral steps towards proper wastewater sludge handling and disposal. Usually the process involves prolonged storage in either specially designed large process buffer tank or even clarification basins depending on the size of treatment system. Certain higher capacity plants will also utilize aerobic digester or facultative lagoon with the primary aim to increase the detention period to store and condition the sludge.

Advanced wastewater system also installs additional facilities such as grit removal and shearing or grinding as special pretreatment steps. Grit removal basically works to remove large particle contaminants so that this can help to reduce wear and tear and also avoid damage to the sludge transfer pumps. Shearing or sludge grinding is also considered an important step because it helps to break down large solid or lumps into smaller size particles so that it won’t clog up piping and jam up inside the pumps. While it may introduce further cost to the whole operation, nevertheless doing this will actually reduces the likelihood of mechanical equipment breakdown which is even harder to deal with.

Sludge Conditioning also involve the use of chemicals or heat treatment system (Zimpro) whereby each method has it own advantages. Thermal stabilization as described earlier in the Zimpro url link above basically involves the use of heat treatment process in order to coagulate and breakdown the solid cell structure while overall reduce some of the water content so that it can be sent later for further decanting. Likewise for chemical conditioning process, either organic or inorganic chemicals or both can be used to achieve the same desired results. Basically choice of organic polymers is more preferred compared to inorganic chemical such as use of ferric chloride since it does not contribute to increase of sludge volume but however, high cost factor is the main reason that prevents widespread use.

Sludge Stabilization using chemicals on the other hand is a process whereby the sludge matter is mixed with chemicals so that it will stabilize the solids in terms of odor and pathogen removal. Further reading on this topic involves the use of lime stabilization to achieve the desired results.

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