title: A new process to improve short-chain fatty acids and bio-methane generation from waste activated sludge.
abstract: As an important intermediate product, short-chain fatty acids (SCFAs) can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane, most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60min can achieve the maximal hydrolyzation. Further, effects of different initial pHs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial pH9.0 with fermentation time of 6d, the production of which was 348.63mg COD/gVSS (6.8 times higher than the blank test) and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally, the effect of this low energy consumption pretreatment on methane generation was investigated.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: 2008zhangdong@tongji.edu.cn.
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Yinguang
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Dai
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: daixiaohu@tongji.edu.cn.
authors.forename: Xiaohu
authors.initials: X
authors.lastname: Dai
mesh_terms: D019149:Bioreactors / Q000382:microbiology; D005232:Fatty Acids, Volatile / Q000032:analysis / Q000378:metabolism*; D005285:Fermentation; D006868:Hydrolysis; D008697:Methane / Q000032:analysis / Q000378:metabolism*; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D005232:Fatty Acids, Volatile; D012722:Sewage; D008697:Methane
keywords: Low energy consumption process; Methane generation; Short-chain fatty acids; Waste activated sludge