title: A modified anaerobic digestion process with chemical sludge pre-treatment and its modelling.
abstract: Activated Sludge Models (ASMs) assume an unbiodegradable organic particulate fraction in the activated sludge, which is derived from the decay of active microorganisms in the sludge and/or introduced from wastewater. In this study, a seasonal change of such activated sludge constituents in a municipal wastewater treatment plant was monitored for 1.5 years. The chemical oxygen demand ratio of the unbiodegradable particulates to the sludge showed a sinusoidal pattern ranging from 40 to 65% along with the change of water temperature in the plant that affected the decay rate. The biogas production in a laboratory-scale anaerobic digestion (AD) process was also affected by the unbiodegradable fraction in the activated sludge fed. Based on the results a chemical pre-treatment using H2O2 was conducted on the digestate to convert the unbiodegradable fraction to a biodegradable one. Once the pre-treated digestate was returned to the digester, the methane conversion increased up to 80% which was about 2.4 times as much as that of the conventional AD process, whilst 96% of volatile solids in the activated sludge was digested. From the experiment, the additional route of the organic conversion processes for the inert fraction at the pre-treatment stage was modelled on the ASM platform with reasonable simulation accuracy.
authors.affiliation: Faculty of Environmental Engineering, The University of Kitakyushu, 1-1, Hibikino, Wakamatsu, Kitakyushu 808-0135, Japan E-mail: hidenari-yasui@kitakyu-u.ac.jp.
authors.forename: N M
authors.initials: NM
authors.lastname: Hai
authors.affiliation: Faculty of Environmental Engineering, The University of Kitakyushu, 1-1, Hibikino, Wakamatsu, Kitakyushu 808-0135, Japan E-mail: hidenari-yasui@kitakyu-u.ac.jp.
authors.forename: S
authors.initials: S
authors.lastname: Sakamoto
authors.affiliation: Research Center for Environmental Technology and Sustainable Development, Hanoi University of Sciences, Vietnam National University, Hanoi, 334 Nguyen Trai Road, Thanh Xuan District, Hanoi, 10000, Vietnam.
authors.forename: V C
authors.initials: VC
authors.lastname: Le
authors.affiliation: GS E&C Research Institute, GS Engineering & Construction Co. Ltd, 417-1, Deokseong-ri, Idon-myeon, Cheoin-gu, Yongin-si, Gyeonggi-do, 449-831, Korea.
authors.forename: H S
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Hydromantis Environmental Software Solutions, Inc., Suite 1601, 1 James Street South, Hamilton, Ontario, L8P4R5, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Goel
authors.affiliation: Faculty of Environmental Engineering, The University of Kitakyushu, 1-1, Hibikino, Wakamatsu, Kitakyushu 808-0135, Japan E-mail: hidenari-yasui@kitakyu-u.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Terashima
authors.affiliation: Faculty of Environmental Engineering, The University of Kitakyushu, 1-1, Hibikino, Wakamatsu, Kitakyushu 808-0135, Japan E-mail: hidenari-yasui@kitakyu-u.ac.jp.
authors.forename: H
authors.initials: H
authors.lastname: Yasui
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D003198:Computer Simulation; D008962:Models, Theoretical; D010100:Oxygen; D012722:Sewage / Q000737:chemistry*; D013995:Time; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D012722:Sewage; D014874:Water Pollutants, Chemical; D010100:Oxygen