Ultrasonic treatment was used treat the CEPT sludge. Metatranscriptomic analysis was used to characterize the microbial community of anaerobic digestion of Ultrasonic-treated CEPT sludge

Hong Kong has the world's largest scale application of Chemical Enhanced Primary Treatment process. The CEPT sludge was collected from local treatment facility. Ultrasonic treatment was applied to enhance the hydrolysis of the CEPT sludge before anaerobic digestion. In order to investigate the effect of ultrasonic treatment on the digestibility of CEPT sludge and corresponding microbial community, anaerobic digestion of ultrasound-treated CEPT sludge was carried out in lab-scale sequential batch reactors. Metatranscriptomes and metagenomes were constructed for the community in the batch reactor at three independent cycles.