The moisture content before sludge drying is very high, the remaining sludge moisture content reaches 99.2% to 99.5%, the sludge moisture content after concentration tank is 95% to 97%, and the moisture content after filtration is about 80%. The reason for reducing the moisture content and sludge drying is that the sludge production in the sewage plant is relatively large, and the sludge volume must be reduced to facilitate subsequent transportation and treatment.