Treatment of Excess Sludge in Internal Circulation Sludge Thickening and Digestion Reactor

Excess sludge from a WWTP was treated by internal circulation sludge thickening and digestion( ICSTD) reactor. The characteristics of excess sludge in the reactor were investigated. The results showed that at temperature from 30 ℃ to 35 ℃,the maximum gas yield was 1. 6 m3/ m3sludge. The methane in biogas was 54% to 75%. The specific resistance to filtration was reduced from 513 × 1012 m / kg to 202 × 1012m / kg,and the sludge dewaterability gradually improved. As indicated by the results of elementary analysis,the reactor had a quite good digestion performance and some nitrogen removal ability. Methanosaeta was predominant species in the reactor.