“…At the same time, the methanogenesis must be prevented to reduce the VFA consumption from methanogens . To date, various methods based on the aforementioned principles have been investigated, which included plentiful pretreatment methods (Zhang et al, 2016;Fu et al, 2015), optimization of key operation parameters (Jiang et al, 2013;Chen and Wu, 2010;Chen et al, 2013a;Luo et al, 2014), and addition of methanogen inhibitor Chen et al, 2013b). However, all of the above-mentioned researches were based on adjusting pH to alkalinity or weak acidity by adding a large amount of NaOH or HCl.…”