Abstract
Anaerobic digestion (AD) of black liquor (BL) in papermaking is of great
significance for energy recovery and environmental sustainability.
Unfortunately, inhibitory compounds, such as aromatic compounds in BL
hinder microbial activities if at high concentration, thus reducing the
efficiency of AD. The AD experiments with different gradients of organic
loading (1, 2, 4, 6, and 8 g COD/L) revealed that the maximum methane production inhibition rate of BL reached 40.74% at 2 g
COD/L. A three-dimensional iron-carbon electrolysis (3D-ICE)
pretreatment was performed for various time intervals (15, 30, 60, and
120 min) before AD (2 g COD/L) to explore the effect of 3D-ICE
pretreatment on improving the AD efficiency. The results showed that the
cumulative methane production changed from 114.10 mL CH4/g COD to 181.55, 139.40, 95.64, and 96.10 mL CH4/g COD, respectively. Moderate electrolysis (15 min)
enhanced the conversion of toxic and/or refractory substances into
readily degradable ones and improved the biochemical characteristics of
BL by degrading the refractory nitrogenous compounds and reducing the
secretion of extracellular polymeric substances. Furthermore, it was
found that the dominant bacteria (e.g. Aminicenantales, Mesotoga)
related to hydrolysis and fermentation of complex compounds such as
aromatic compounds and acetotrophic methanogenic archaea (e.g. Methanosaeta)
were significantly enriched, which was conducive to the conversion of
organic matters in BL into methane. This also indicated the positive
effect of 3D-ICE. Generally, 3D-ICE combined with AD is considered as an
effective way to recover energy from BL.
Original language | English |
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Article number | 108115 |
Journal | Journal of Environmental Chemical Engineering |
Volume | 10 |
Issue number | 4 |
Number of pages | 10 |
ISSN | 2213-3437 |
DOIs | |
Publication status | Published - 2022 |
Keywords
- Black liquor
- anaerobic digestion
- Three-dimensional iron-carbon electrolysis
- Extracellular polymeric substances
- Microbial community