Enhancing anaerobic digestion of waste activated sludge by dielectric barrier discharge pretreatment: Nutrient release, sludge hydrolysis and microbial community succession

A dielectric barrier discharge (DBD) pretreatment of waste activated sludge (WAS) was developed for boosting the releasing of organic matter from floc structures and microbial cells. The changes of protein and polysaccharide in different extracellular polymeric substances layers of SCOD releasing from sludge were determined by using three-dimensional fluorescence spectra. Significantly improved cumulative methane production was achieved via enhancing anaerobic digestion, which was 83.5% higher than that of the control. The formed center dot OH radicals play a key role in sludge hydrolysis, thus improving the biodegradability of WAS. Furthermore, highthroughput sequencing analysis showed that DBD pretreatment improved the relative abundances of the main functional microbes with respect to sludge hydrolysis and anaerobic digestion. Therefore, this study verifies the feasibility of DBD pretreatment in sludge hydrolysis and is expected to provide a practical new technology for anaerobic digestion of WAS.