title: Improved volatile fatty acids anaerobic production from waste activated sludge by pH regulation: Alkaline or neutral pH?
abstract: In this study, the anaerobic fermentation was carried out for volatile fatty acids (VFAs) production at different pH (between 7.0 and 10.0) conditions with untreated sludge and heat-alkaline pretreated waste activated sludge. In the fermentation with untreated sludge, the extent of hydrolysis of organic matters and extent of acidification at alkaline pH are 54.37% and 30.37%, respectively, resulting in the highest VFAs yield at 235.46mg COD/gVS of three pH conditions. In the fermentation with heat-alkaline pretreated sludge, the acidification rate and VFAs yield at neutral pH are 30.98% and 240.14mg COD/gVS, respectively, which are higher than that at other pH conditions. With the glucose or bovine serum albumin as substrate for VFAs production, the neutral pH showed a higher VFAs concentration than the alkaline pH condition. The results of terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that the alkaline pH caused low microbial richness. Based on the results in this study, we demonstrated that the alkaline pH is favor of hydrolysis of organic matter in sludge while neutral pH improved the acidogenesis for the VFAs production from sludge. Our finding is obvious different to the previous research and helpful for the understanding of how heat-alkaline pretreatment and alkaline fermentation influence the VFAs production, and beneficial to the development of VFAs production process.
authors.affiliation: School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, China.
authors.forename: Huijun
authors.initials: H
authors.lastname: Ma
authors.affiliation: School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, China.
authors.forename: Xingchun
authors.initials: X
authors.lastname: Chen
authors.affiliation: School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, 214122 Wuxi, China. Electronic address: liuhe@jiangnan.edu.cn.
authors.forename: He
authors.initials: H
authors.lastname: Liu
authors.affiliation: School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, 214122 Wuxi, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Liu
authors.affiliation: School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, 214122 Wuxi, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Fu
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D002417:Cattle; D005232:Fatty Acids, Volatile / Q000737:chemistry*; D005285:Fermentation; D005947:Glucose / Q000737:chemistry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D012150:Polymorphism, Restriction Fragment Length; D011134:Polysaccharides / Q000737:chemistry; D011506:Proteins / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D012995:Solubility; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater; D018508:Water Purification / Q000379:methods
chemical_list: D005232:Fatty Acids, Volatile; D005947:Glucose; D011134:Polysaccharides; D011506:Proteins; D012710:Serum Albumin, Bovine; D012722:Sewage; D062065:Wastewater
keywords: Alkaline pH; Anaerobic fermentation; Neutral pH; Pretreatment; Volatile fatty acids; Waste activated sludge