Strategies for recovery of imbalanced full-scale biogas reactor feeding with palm oil mill effluent.

Content Provider	Europe PMC
Author	Wongfaed, Nantharat Kongjan, Prawit Suksong, Wantanasak Prasertsan, Poonsuk O-Thong, Sompong
Editor	Eroglu, Ela
Copyright Year	2021
Abstract	BackgroundFull-scale biogas production from palm oil mill effluent (POME) was inhibited by low pH and highly volatile fatty acid (VFA) accumulation. Three strategies were investigated for recovering the anaerobic digestion (AD) imbalance on biogas production, namely the dilution method (tap water vs. biogas effluent), pH adjustment method (NaOH, NaHCO3, Ca(OH)2, oil palm ash), and bioaugmentation (active methane-producing sludge) method. The highly economical and feasible method was selected and validated in a full-scale application.ResultsThe inhibited sludge from a full-scale biogas reactor could be recovered within 30–36 days by employing various strategies. Dilution of the inhibited sludge with biogas effluent at a ratio of 8:2, pH adjustment with 0.14% w/v NaOH, and 8.0% w/v oil palm ash were considered to be more economically feasible than other strategies tested (dilution with tap water, or pH adjustment with 0.50% w/v Ca(OH)2, or 1.25% NaHCO3 and bioaugmentation) with a recovery time of 30–36 days. The recovered biogas reactor exhibited a 35–83% higher methane yield than self-recovery, with a significantly increased hydrolysis constant (kH) and specific methanogenic activity (SMA). The population of Clostridium sp., Bacillus sp., and Methanosarcina sp. increased in the recovered sludge. The imbalanced full-scale hybrid cover lagoon reactor was recovered within 15 days by dilution with biogas effluent at a ratio of 8:2 and a better result than the lab-scale test (36 days).ConclusionDilution of the inhibited sludge with biogas effluent could recover the imbalance of the full-scale POME-biogas reactor with economically feasible and high biogas production performance.
Journal	Peerj
Volume Number	9
PubMed Central reference number	PMC7797170
PubMed reference number	33505799
e-ISSN	21678359
DOI	10.7717/peerj.10592
Language	English
Publisher	PeerJ Inc.
Publisher Date	2021-01-07
Publisher Place	San Diego, USA
Access Restriction	Open
Rights License	This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited. ©2021 Wongfaed et al.
Subject Keyword	Acidified inhibition Full-scale biogas plant Microbial community Organic overloading Palm oil mill effluent Recovery strategy
Content Type	Text
Resource Type	Article
Subject	Neuroscience Medicine Agricultural and Biological Sciences Biochemistry, Genetics and Molecular Biology