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Title: In-situ biogas upgrading during anaerobic digestion of food waste amended with walnut shell biochar at bench scale

Here, a modified version of an in-situ CO 2 removal process was applied during AD of food waste with two types of walnut shell biochar (WSB) at bench-scale under batch operating mode. Compared to the coarse WSB, the fine WSB has a higher ash content (43 vs. 36 wt%) and higher concentrations of calcium (31 vs. 19 wt% of ash), magnesium (8.4 vs. 5.6 wt% of ash) and sodium (23.4 vs. 0.3 wt% of ash), but a lower potassium concentration (0.2 vs. 40% wt% of ash). The 0.96 - 3.83 g biochar (g VS added) -1 fine WSB amended digesters produced biogas with 77.5-98.1% CH 4 content by removing 40-96% of the CO 2 compared to the control digesters at mesophilic and thermophilic temperature conditions. In a direct comparison at 1.83 g biochar (g VS added) -1, the fine WSB amended digesters (85.7% CH 4 content and 61% CO 2 removal) outperformed the coarse WSB amended digesters (78.9% CH 4 content and 51% CO 2 removal). Biochar addition also increased alkalinity as CaCO3 from 2,800 mg L -1 in the control digesters to 4,800-6,800 mg L -1 providing process stability for food waste AD.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Argonne National Lab. (ANL), Lemont, IL (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Waste Management and Research
Additional Journal Information:
Journal Volume: 35; Journal Issue: 6; Journal ID: ISSN 0734-242X
Publisher:
SAGE
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
California Energy Commission; USDOE
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 09 BIOMASS FUELS; CO2 removal; renewable methane; anaerobic digestion; biochar; food waste
OSTI Identifier:
1371563