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Assessment of the potential for biogas production from wheat straw leachate in upflow anaerobic sludge blanket digesters

Assessment of the potential for biogas production from wheat straw leachate in upflow anaerobic sludge blanket digesters
Assessment of the potential for biogas production from wheat straw leachate in upflow anaerobic sludge blanket digesters
Wheat straw is a major potential source of waste biomass for renewable energy production, but its high salt content causes problems in combustion. The salts can be removed by washing, but this process also removes a proportion of the organic material which could potentially be recovered by anaerobic digestion of the washwater leachate. This approach would maximise the overall energy yield in an integrated process in which washwater could be recycled after further desalting. Leachate from cold water washing with a chemical oxygen demand (COD) of 1.2 g l?1 was fed to mesophilic upflow anaerobic sludge blanket (UASB) digesters at a loading rate of 1 g COD l?1 day?1 to determine the energy yield and any detrimental effects of the leached salts on the process. The specific methane production was 0.29 l CH4 g?1 CODadded, corresponding to a COD removal rate of 84%. Light metal cations in the leachate, especially potassium, were found to accumulate in the digesters and appeared to have a synergistic effect up to a concentration of ?6.5 mg K g?1 wet weight of the granular sludge, but further accumulation caused inhibition of methanogenesis. It was shown that gas production in the inhibited digesters could be restored within 12 days by switching the feed to a synthetic sewage, which washed the accumulated K out of the digesters.
anaerobic digestion, osmo-regulation, potassium, salinity inhibition, wheat straw leachate
0273-1223
2737-2744
Idrus, S.
8604cd14-7f21-416d-ab23-433843ef6ed2
Banks, C. J.
5c6c8c4b-5b25-4e37-9058-50fa8d2e926f
Heaven, S.
f25f74b6-97bd-4a18-b33b-a63084718571
Idrus, S.
8604cd14-7f21-416d-ab23-433843ef6ed2
Banks, C. J.
5c6c8c4b-5b25-4e37-9058-50fa8d2e926f
Heaven, S.
f25f74b6-97bd-4a18-b33b-a63084718571

Idrus, S., Banks, C. J. and Heaven, S. (2012) Assessment of the potential for biogas production from wheat straw leachate in upflow anaerobic sludge blanket digesters. Water Science & Technology, 66 (12), 2737-2744. (doi:10.2166/wst.2012.511).

Record type: Article

Abstract

Wheat straw is a major potential source of waste biomass for renewable energy production, but its high salt content causes problems in combustion. The salts can be removed by washing, but this process also removes a proportion of the organic material which could potentially be recovered by anaerobic digestion of the washwater leachate. This approach would maximise the overall energy yield in an integrated process in which washwater could be recycled after further desalting. Leachate from cold water washing with a chemical oxygen demand (COD) of 1.2 g l?1 was fed to mesophilic upflow anaerobic sludge blanket (UASB) digesters at a loading rate of 1 g COD l?1 day?1 to determine the energy yield and any detrimental effects of the leached salts on the process. The specific methane production was 0.29 l CH4 g?1 CODadded, corresponding to a COD removal rate of 84%. Light metal cations in the leachate, especially potassium, were found to accumulate in the digesters and appeared to have a synergistic effect up to a concentration of ?6.5 mg K g?1 wet weight of the granular sludge, but further accumulation caused inhibition of methanogenesis. It was shown that gas production in the inhibited digesters could be restored within 12 days by switching the feed to a synthetic sewage, which washed the accumulated K out of the digesters.

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Published date: 2012
Keywords: anaerobic digestion, osmo-regulation, potassium, salinity inhibition, wheat straw leachate
Organisations: Centre for Environmental Science

Identifiers

Local EPrints ID: 345824
URI: http://eprints.soton.ac.uk/id/eprint/345824
ISSN: 0273-1223
PURE UUID: 45e7ca7f-7669-4480-aa01-ef780effba1c
ORCID for S. Heaven: ORCID iD orcid.org/0000-0001-7798-4683

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Date deposited: 05 Oct 2015 15:53
Last modified: 17 Mar 2020 01:25

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