Abstract
Bioaugmentation of ammonia-tolerant methanogens into inhibited anaerobic
digestion (AD) reactors was demonstrated as an in-situ remediation
strategy to alleviate ammonia toxicity. This study investigated the
long-term performance of a novel bioaugmentation strategy, using
gel-immobilized ammonia tolerant methanogens (biogel) enhanced with
biochar to alleviate ammonia toxicity in thermophilic continuous
anaerobic systems. Three ammonia shocks were applied in four continuous
stirred-tank reactors, namely by adding biogel (R2), biochar (R3), both biogel and biochar (R4) and control reactor (R1), respectively. The results showed R1, R2, R3 and R4 suffered 31.3%, 28.6%, 26.0% and 17.1% methane production loss, respectively at 5.5 g NH4+-N L−1. R4 achieved 100% methane production recovery compared to 13% of R1. R3 and R4 successfully acclimatized to 6.5 g NH4+-N L−1 with 71.7% and 61.8% original methane yield compared to 36.9% and 35.6% for R1 and R2, respectively. The introduced Methanoculleus thermophilus sp. along with syntrophic partners was protected by the biochar, and its relative abundance in R4 was tenfold than R2.
Bioaugmentation developed a long-term ammonia resistance due to the
synergistic interaction between biogel and biochar on alleviating
ammonia inhibition, securing an additional gross profit of 11.8 $ ton−1 feedstock for the continuous biogas reactor.
Original language | English |
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Journal | Renewable Energy |
Volume | 195 |
Pages (from-to) | 590-597 |
Number of pages | 8 |
ISSN | 0960-1481 |
DOIs | |
Publication status | Published - 2022 |
Keywords
- Ammonia shock
- biochar
- Immobilized methanogens
- Methanosarcina spp.
- Syntrophic bacteria