Insight of persulfate-based treatments induced stable volatile fatty acids promotion during waste activated sludge anaerobic fermentation in semi-continuous-flow reactors: Focusing on variations of substrate and microbial functional profiles - Qin Zhang; Yuke Xu; Wenzhuo Li; Yiyun Liu; Zailiang Liu; Jun Zheng; Huijuan Zhang; Jingyang Luo (Journal of Cleaner Production, 2024)