title: Alkaline-mechanical pretreatment process for enhanced anaerobic digestion of thickened waste activated sludge with a novel crushing device: Performance evaluation and economic analysis.
abstract: Although various pretreatments have been widely investigated to enhance the anaerobic digestion (AD) of waste activated sludge (WAS), economic feasibility issues have limited real-world applications. The authors examined the performance and economic analysis of an alkaline-mechanical process with a novel mechanical crushing device for thickened WAS pretreatment. The pretreatment at 40gTS/L, pH 13, and 90min reaction time achieved 64% of solubilization efficiency and 8.3 times higher CH4 yield than the control. In addition, a synergistic CH4 yield enhancement was observed when the pretreated and raw WAS were used together as feedstock, and the greatest synergy was observed at a volumetric mixture ratio of 50:50. Economic estimates indicate that up to 22% of WAS treatment costs would be saved by the installation of the suggested process. The experimental results clearly indicate that the alkaline-mechanical process would be highly effective and economically feasible for the AD of thickened WAS.
authors.affiliation: Department of Civil and Environmental Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, Republic of Korea.
authors.forename: Si-Kyung
authors.initials: SK
authors.lastname: Cho
authors.affiliation: Department of Environmental Engineering, Daegu University, Jillyang, Gyeongsan, Gyeongbuk 712-714, Republic of Korea.
authors.forename: Hyun-Jun
authors.initials: HJ
authors.lastname: Ju
authors.affiliation: Willtech, R&DB Center 305, Gyeongsan, Gyeongbuk 712-902, Republic of Korea.
authors.forename: Jeong-Gyu
authors.initials: JG
authors.lastname: Lee
authors.affiliation: Department of Environmental Engineering, Daegu University, Jillyang, Gyeongsan, Gyeongbuk 712-714, Republic of Korea. Electronic address: sanghkim1@daegu.ac.kr.
authors.forename: Sang-Hyoun
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000693:Anaerobiosis / Q000187:drug effects; D000704:Analysis of Variance; D008697:Methane / Q000096:biosynthesis; D012722:Sewage / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000494:pharmacology*; D012995:Solubility; D014866:Waste Products / Q000032:analysis*; D018508:Water Purification / Q000191:economics* / Q000295:instrumentation / Q000379:methods*
chemical_list: D012722:Sewage; D014866:Waste Products; D012972:Sodium Hydroxide; D008697:Methane
keywords: Alkaline-mechanical pretreatment; Anaerobic digestion; Co-metabolism; Economic analysis; Waste activated sludge