Effect of Substrate to Inoculum Ratio on Bioenergy Recovery from Food Waste, Yard Waste, and Biosolids by High Solids Anaerobic Digestion

Phillip J. Dixon, Sarina J. Ergas, James R. Mihelcic, Shakira R. Hobbs

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Residual biosolids from wastewater treatment facilities and the organic fraction of municipal solid waste (OFMSW), e.g., food and yard wastes (FW and YW), are difficult to manage due to increased waste generation and recent stringent regulations. The effect of substrate to inoculum ratio (S/I) on biochemical transformation mechanisms and biomethane production during high solids anaerobic digestion of FW, YW, and biosolids were investigated. Biochemical methane potential (BMP) assays were set up under mesophilic conditions at S/I of 1.0, 2.0, and 3.0 g OFMSW total solids (TS)/g inoculum TS. BMP with the lowest S/I (1.0) produced the highest cumulative CH4 yield of 126 mL CH4/(g VSadded), with 90% of its maximum yield by day 37, and a hydrolysis rate constant of 0.06/day. S/I 2.0 and 3.0 led to higher volatile fatty acid release than S/I 1.0. This resulted in pH-induced inhibition of methanogenesis, longer lag phases, and lower cumulative CH4 yields [S/I = 2.0 at 45.6-mL CH4/(g VSadded); S/I = 3.0 at 6.75-mL CH4/(g VSadded). The results showed that accumulation of inhibitory intermediates could cause system failure due to mass transfer limitation under low moisture conditions when S/I > 1.0 based on TS.

Original languageEnglish
Pages (from-to)1459-1465
Number of pages7
JournalEnvironmental Engineering Science
Volume36
Issue number12
DOIs
StatePublished - Dec 2019

Bibliographical note

Funding Information:
This material is based upon work supported by the Hinkley Center for Solid and Hazardous Waste Management and the National Science Foundation under Grant No. 1243510.

Keywords

  • biochemical methane potential
  • biosolids
  • high solids anaerobic digestion
  • hydrolysis rate constants
  • organic fraction of municipal solid waste

ASJC Scopus subject areas

  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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