Introduction to Sludge Treatment Processes

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This post was last edited by yuchenchf on 2017-9-26 08:32. The treatment processes for sludge include methods such as concentration, digestion, dewatering, drying, and incineration, as well as final disposal. 　　(1) Sludge thickening. The purpose of sludge concentration is to initially dehydrate the sludge and reduce its volume, thereby creating conditions for further treatment. Concentration and dewatering methods include gravity sedimentation concentration, flotation concentration, and other concentration methods. 　　(2) Sludge digestion. To reduce the amount of sludge, prevent environmental pollution, and improve its value, it is generally necessary to subject it to digestion treatment. Sludge digestion involves using the metabolic activities of microorganisms to break down the organic substances in sludge into stable compounds, eliminating odors, killing parasite eggs, and reducing the volume of the sludge. The biogas produced during this process is also recovered and utilized. 　　(3) Sludge dewatering and drying. After concentration and digestion, the sludge still has a moisture content of around 96%, and its volume is large, making it difficult to transport and use; further dewatering and drying are required. The main methods for this purpose are natural evaporation and mechanical dewatering. 　　(4) Sludge incineration. After sludge is dried, its moisture content still ranges from 10% to 15%, and its volume remains large. Incineration can completely remove the moisture and organic impurities from the sludge, as well as kill pathogenic microorganisms. When some sludge contains toxic substances and is not suitable as agricultural fertilizer, or when it is difficult to utilize for other reasons, incineration is also used to prevent pollution. The device for burning sludge is a incinerator. 　　(5) Final treatment of sludge. When the sludge contains toxic substances such as heavy metal ions, further treatment is required, such as deep burial or disposal in the ocean. But final processing is generally rarely carried out; instead, it is used as needed during the processing process.