Cited by 78Anaerobic Digestion and Biogas ProductionMicrobial Fuel Cells and BioremediationWastewater Treatment and Nitrogen Removal

Continuous medium chain carboxylic acids production from excess sludge by granular chain-elongation process

Wu, Qinglian, Feng, Xiaochi, Chen, Ying, Liu, Min, Bao, Xian·2021·Journal of Hazardous Materials

Abstract

Short chain carboxylic acids (SCCAs) production is one of the primary ways to recycle excess sludge (ES). However, the high cost for the SCCAs separation/extraction due to its complete miscibility in water hinders the practical application of SCCAs and the popularization of this recycling way. To overcome this barrier, this study performed an emerging chain elongation (CE) technology to upgrade the SCCAs-rich sludge fermentation broth into the highly hydrophobic medium chain carboxylic acids (MCCAs). In a continuous expanded granule sludge bed (EGSB) reactor, a maximal MCCAs yield of 67.39 % and the corresponding concentration of 9.80 g COD/L (224.97 mM C/L) were achieved. By supplying CO 2 at a loading rate of 2 [Formula: see text] to lower the hydrogen partial pressure, the ethanol utilization rate and the resulting MCCAs yield were further improved. In addition, three branched-MCCAs including iso-caproate, iso-heptylate, and iso-caprylate were obtained the first time from waste biomass with the average proportions of 6.17 %, 3.65 %, and 0.8 %, respectively. The branched-MCCAs came from the CE of branched-SCCAs. The granule sludges performing CE were mainly consisted of rod-shaped cells, and dominated by Clostridium sensu stricto and Clostridium IV. This study is expected to lay a foundation for recycling ES to MCCAs.

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Crossref · 10.1016/j.jhazmat.2020.123471

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  • CO2 supply facilitated oxidation of ethanol to acetyl-CoA by lowering partial pressure of hydrogen.

    “The CO2 supply facilitated oxidation of ethanol to acetyl-CoA by lowering the partial pressure of hydrogen [91].”

    From Food Waste Biorefinery: Pathway towards Circular Bioeconomy (2021) · cites this paper as [91]

  • A maximum yield of 72.86% of medium chain carboxylic acids was achieved by adding ethanol and CO2 at a loading rate of 2 L/d and 2.5-day hydraulic retention time of sludge fermentation broth.

    “They achieved maximum yield of 72.86% of medium chain carboxylic acids by adding ethanol and CO2 (at a loading rate of 2 L/d) at 2.5-day hydraulic retention time of sludge fermentation broth [91].”

    From Food Waste Biorefinery: Pathway towards Circular Bioeconomy (2021) · cites this paper as [91]

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Authors
Wu, Q., Feng, X., Chen, Y., Liu, M., & Bao, X.
Affiliations
  • Sichuan University (CN)
  • Harbin Institute of Technology (CN)
  • Nanyang Technological University (SG)
Corresponding author
Bao, Xian
Venue
Journal of Hazardous Materials
Publisher
Elsevier BV
Published
2021-01
Volume
402
Pages
123471
ISSN
0304-3894 (ISSN-L)
OpenAlex
W3042294927
Cited by
78
References
54
Citations by year
2026: 6 · 2025: 5 · 2024: 19 · 2023: 20 · 2022: 7 · 2021: 18 · 2020: 3
FWCI
6.36
Type
journal article
Language
en
Open access
closed
Locations
  • Journal of Hazardous Materials (publishedVersion)
  • PubMed (publishedVersion)
  • DR-NTU (Nanyang Technological University) (submittedVersion)
Funders
Sichuan Province Science and Technology Support Program
Topics
  • Physical Sciences › Engineering › Building and Construction › Anaerobic Digestion and Biogas Production
  • Physical Sciences › Environmental Science › Environmental Engineering › Microbial Fuel Cells and Bioremediation
  • Physical Sciences › Environmental Science › Pollution › Wastewater Treatment and Nitrogen Removal
Keywords
medium-chain carboxylic acids, chain extension, expanded granular sludge bed, short-chain carboxylic acids, branched carboxylic acids, CO2 supply, hydrogen partial pressure, ethanol utilization, Clostridium sensu stricto, biomass waste valorization
MeSH terms
Ethanol, Carboxylic Acids, Fermentation, Sewage, Biomass, Bioreactors

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