Enhanced methane production from waste-activated sludge via sodium percarbonate-assisted thermal hydrolysis

The development of efficient pretreatment technologies is an urgent task for the waste-activated sludge treatment industry. In this study, a novel sodium percarbonate (SPC)-assisted thermal hydrolysis (TH) pretreatment method was proposed and evaluated for its performance in sludge solubility and enhancing methane production. SPC (0.1 g/g total suspended solids, 24 h) assisted TH (140 °C, 30 min) pretreatment increased methane production by 37 % compared to the control, from 130 ± 4 mL/g volatile solids (VS) to 178 ± 5 mL/g VS. The free radicals produced by SPC induced the destruction of extracellular polymeric substances and the rupture of sludge cells, thus facilitating the release of organic matter such as proteins and polysaccharides.TH destroyed the sludge flocs with high temperature and high pressure while activating SPC to produce more free radicals, which further increased the solubility of the sludge. In addition, the SPC-assisted TH pretreatment enriched Firmicutes and Methanobacterium sp. This study revealed the synergistic effect of SPC and TH, providing an economical, effective, and environmentally friendly pretreatment technology for sludge treatment and methane production.