Comparison between thermophilic and mesophilic anaerobic digestion of waste activated sludge by combined NaOH-microwave pretreatment

The purpose of this study was to investigate the performance of the thermophilic and mesophilic anaerobic digestion process (TADP, MADP) fed with NaOH-microwave pretreated waste activated sludge. The experiment was conducted in anaerobic CSTR reactors. During this experiment, the reactors were stable in operation and were not inhibited by ammonia. The methane production and reduction of organic matters from MADP were less than those from TADP. The dewatering performance of mesophilic sludge was better than that of the thermophilic sludge. The experimental results showed that the continuous TADP and MADP were effective, when the reactors were fed with the waste activated sludge pretreated by NaOH-microwave. MADP was more suitable to combine the NaOH-MW pretreatment process than TADP.

Automated summary

This study investigated the performance of TADP and MADP fed with NaOH-microwave pretreated waste activated sludge. The results showed that MADP had lower methane production and reduction of organic matters compared to TADP, but had better dewatering performance for mesophilic sludge. Therefore, MADP is more suitable for the NaOH-MW pretreatment process.