Study on deep dewatering and resource utilization of sludge in municipal sewage treatment plant

In this study, the sludge of three municipal sewage treatment plants in Foshan City, Guangdong Province, China, was dewatered and recycled. The experimental results shown that after deep dewatering with different chemical conditioning reagents, the moisture content of municipal sewage sludge was decreased greatly, from about 97% to about 55%. After dewatering, the organic matter content of sludge was maintained at a high level which is beneficial to the composting treatment of the sludge. The organic matter content of sludge in Foshan No. 1 Sewage Treatment Plant and No. 2 Sewage Treatment Plant was more than 30%, while it was between 15% and 20% in Foshan No. 3 Sewage Treatment Plant. Sludge from all three sewage treatment plants neeed to add a small amount of nutrients to compost. After 14 days of the aerobic composting, the moisture content of the sewage sludge could be reduced to less than 50%, and all the index met the requirements of the agricultural standard.