title: Hydrolysis-acidogenesis of food waste in solid-liquid-separating continuous stirred tank reactor (SLS-CSTR) for volatile organic acid production.
abstract: The use of conventional continuous stirred tank reactor (CSTR) can affect the methane (CH4) recovery in a two-stage anaerobic digestion of food waste (FW) due to carbon short circuiting in the hydrolysis-acidogenesis (Hy-Aci) stage. In this research, we have designed and tested a solid-liquid-separating CSTR (SLS-CSTR) for effective Hy-Aci of FW. The working conditions were pH 6 and 9 (SLS-CSTR-1 and -2, respectively); temperature-37°C; agitation-300rpm; and organic loading rate (OLR)-2gVSL(-1)day(-1). The volatile fatty acids (VFA), enzyme activities and bacterial population (by qPCR) were determined as test parameters. Results showed that the Hy-Aci of FW at pH 9 produced ∼35% excess VFA as compared to that at pH 6, with acetic and butyric acids as major precursors, which correlated with the high enzyme activities and low lactic acid bacteria. The design provided efficient solid-liquid separation there by improved the organic acid yields from FW.
authors.affiliation: Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region, PR China.
authors.forename: Obulisamy Parthiba
authors.initials: OP
authors.lastname: Karthikeyan
authors.affiliation: Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region, PR China.
authors.forename: Ammaiyappan
authors.initials: A
authors.lastname: Selvam
authors.affiliation: Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region, PR China. Electronic address: jwcwong@hkbu.edu.hk.
authors.forename: Jonathan W C
authors.initials: JW
authors.lastname: Wong
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000143:Acids / Q000737:chemistry; D019149:Bioreactors; D020148:Butyric Acid / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D004798:Enzymes / Q000737:chemistry; D004867:Equipment Design; D005232:Fatty Acids, Volatile / Q000032:analysis* / Q000737:chemistry; D005502:Food; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008697:Methane / Q000032:analysis*; D012037:Refuse Disposal / Q000379:methods*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods
chemical_list: D000143:Acids; D004798:Enzymes; D005232:Fatty Acids, Volatile; D020148:Butyric Acid; D002244:Carbon; D008697:Methane; D019342:Acetic Acid
keywords: CSTR; Food waste; Hydrolysis–acidogenesis; Solid- and hydraulic-retention time; Volatile fatty acids