Abstract
Acetic acid and methanol are found in wastewater of many
industries and they can be excellent substrates for anaerobic digestion
(AD). However, the research determining the efficient use of these
wastewater as AD substrates and evaluating their impact on the AD
process is scarce. The current study aims to assess the use of acetic
acid-rich (WW-HAc) and methanol-rich (WW–MeOH) wastewater for methane
production by evaluating (1) their effect on the AD process pH, (2)
their toxicity on a typical non-acclimated methanogenic inoculum, (3)
their effect on the methanogenic activity and (4) their effect on the
acetate metabolic pathway when co-digested in continuous, manure-based anaerobic reactors. The pH experimental results showed that an organic loading (OL) of 5.97 g VS L−1
of WW-HAc lowered the pH below the optimum range for AD (6.5–8.5). The
toxicity test on AD process showed that IC50 (half-maximal inhibitory
concentration) was 6.9 and 14.31 g VS L−1 for WW-HAc and WW-MeOH, respectively. In the continuous reactors experiment, high organic loading rates of up to 5.7 and 9.7 g VS L−1 d−1
for WW-HAc and WW-MeOH, respectively, where achieved under steady state
(i.e., less than 10% variation in production), with 79% and 87%,
respectively of the maximum theoretical methane production.
Radioisotopic analysis showed that aceticlastic methanogenesis was
dominant in both reactors. Overall, the assessment of using acetic
acid-rich and methanol-rich wastewater as substrates, revealed
significant production benefits for the AD process together with
operational restrictions that must be followed to prevent toxicities or
overloading effects.
Original language | English |
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Article number | 110987 |
Journal | Renewable and Sustainable Energy Reviews |
Volume | 144 |
Number of pages | 9 |
ISSN | 1364-0321 |
DOIs | |
Publication status | Published - 2021 |
Keywords
- Acetic acid
- Anaerobic co-digestion
- Cow manure
- CSTR
- Methanogenic pathway
- Methanol
- Radioisotope