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Enhanced methane production from the co-digestion of food waste and thermally hydrolyzed sludge filtrate
Although many technologies can be applied to sewage sludge (SS) and food waste (FW) treatment, high investment and operational costs, high land occupation, and the “not-in-my-backyard” effect pose many challenges in practice. Thus, it is important to develop and utilize low-carbon or negative-carbon...
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Published in: | Journal of environmental management 2023-09, Vol.342, p.118169-118169, Article 118169 |
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Main Authors: | , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Although many technologies can be applied to sewage sludge (SS) and food waste (FW) treatment, high investment and operational costs, high land occupation, and the “not-in-my-backyard” effect pose many challenges in practice. Thus, it is important to develop and utilize low-carbon or negative-carbon technologies to tackle the carbon problem. This paper proposes a method of anaerobic co-digestion of FW and SS, thermally hydrolyzed sludge (THS), or THS filtrate (THF) to enhance their methane potential. Compared to the co-digestion of SS with FW, the methane yield of the co-digestion of THS and FW was 9.7–69.7% higher, and that of the co-digestion of THF and FW was 11.1–101.1% higher. The synergistic effect was weakened with the addition of THS but enhanced with the addition of THF, potentially owing to the change in humic substances. Filtration removed most humic acids (HAs) from THS but retained fulvic acids (FAs) in THF. Moreover, THF produced 71.4% of the methane yield of THS, although only 25% of the organic matter permeated from THS to THF. This indicated that hardly biodegradable substances remained in the dewatering cake and were removed from anaerobic digestion systems. The results indicate that the co-digestion of THF and FW is an effective way to enhance methane production.
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•Thermally hydrolyzed sludge (THS) and its filtrate (THF) were tested in co-digestion.•THF exhibited better synergistic effect in the co-digestion with food waste than THS.•Co-digestion of THF and food waste lead to a methane yield of 338 mL/g COD at most.•Mechanical filtration removed humic acids from THS but remained fulvic acids in THF.•THF contained 25% COD of THS, but produced 75% of methane yield of THS. |
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ISSN: | 0301-4797 1095-8630 |
DOI: | 10.1016/j.jenvman.2023.118169 |