Comparing two enhancing methods for improving kitchen waste anaerobic digestion: bentonite addition and autoclaved de-oiling pretreatment

Duojiao Zhang, Na Duan*, Hailin Tian, Cong Lin, Yilin Zhang, Zhidan Liu

*Corresponding author for this work

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The effects of different enhancement methods, including adding bentonite (1.25%, w/w, wet substrate) and autoclaved de-oiling pretreatment (121 °C, 30 minutes), on the anaerobic digestion of kitchen waste (KW) were comparably studied. Mesophilic continuous stirred tank reactors were used under different organic loading rates (OLRs) of 1.11 to 1.84 gVS (volatile solid)L−1d−1 and two different hydraulic retention times (HRTs) (20 d and 25 d). In this study, two enhancement methods and extending HRT could prevent volatile fatty acids (VFA) accumulation and obtain a high methane production at low OLR. Owing to the effect of providing nutrients and buffering capacity, the maximum methane yield was obtained with adding bentonite at OLR of 1.39 gVSL−1d−1. However, for high OLR (1.84 gVSL−1d−1), a decrease of the methane yield and system breakdown occurred due to the accumulation of VFAs. Engineering design and process evaluation of a CSTR biogas plant treating with KW based on the laboratory experiment was stated.
Original languageEnglish
JournalProcess Safety and Environmental Protection
Pages (from-to)116-124
Publication statusPublished - 2018


  • Anaerobic digestion
  • Kitchen waste
  • Bentonite
  • Autoclaved de-oiling

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