Solubilizing waste activated sludge via thermal treatment to enhance the biodegradability

Abstract

The current work intends to unveil the performance of thermal treatment in improving the biodegradability of waste activated sludge (WAS). The thermal treatments of WAS were conducted at different temperatures (30oC, 60oC, 75oC, 90oC) as well as treatment durations (0, 1, 2, 4, 8, 16 hours), and its effects on the sludge biodegradability were measured in terms of soluble chemical oxygen demand (SCOD). The ANOVA analysis showed that both treatment temperature (P<0.001) and duration (P<0.001) had significantly enhanced the biodegradability of WAS. Accordingly, the results showed that the SCOD increased with increasing treatment temperature, with 90oC thermal treatment at 16 hours producing the highest SCOD of 163.39g/L. Although SCOD increased with longer treatment duration, the highest SCOD increment happened within the first 4 hours of treatment before slowing down gradually. Besides, the interaction between treatment temperature and duration was also significant (P[removed].