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Lucero Saucedo, Sofia Liliana

University of British Columbia

Anaerobic digestion (AD) systems offer a sustainable approach for biomass resource recovery and energy production. This study explores the potential of solid digestate-derived biochar as an additive to enhance the stability and performance of AD systems, focusing on the effects of biochar dosage, pyrolysis temperature, and pyrolysis catalyst on methane production. Two series of tests were conducted: Test Series 1 using a mixture of chicken, hog, and dairy manure as the substrate, and Test Series 2 employing synthetic food waste. In Test Series 1, biochemical methane potential (BMP) tests were performed with biochar dosages of 0.1 and 0.6 g/g Total Solids. Results showed a marginal improvement in specific methane yield (SMY) at the lower dosage, but an increase of 9.0-53.5% at the higher dosage across all biochar types compared to the control. Hence, the study found a dosage-dependent relationship. The influence of pyrolysis temperature (400°C vs. 500°C) and catalysts (20 wt% K3PO4 vs. 10 wt% K3PO4/10 wt% clinoptilolite) on SMY exhibited opposite trends, and no direct correlation was found between specific surface area of biochar and SMY. In Test Series 2, BMP assays using synthetic food waste revealed a dosage-dependent relationship with SMY. At a lower biochar dosage (0.1 g/g TS), improvements in methane production were marginal, while a higher dosage (0.6 g/g TS) increased methane content by at least 10%, with yield improvements ranging from 35% to 52%. A three-way ANOVA indicated that biochar dosage significantly influenced methane yield, while pyrolysis temperature and catalyst had no statistically significant impact. Multiple linear regression analysis identified the dosage-adjusted aromaticity index as a significant factor affecting SMY, with a unit increase correlating to a 327 mL/g VS increase in SMY. The findings highlight the potential of solid digestate-derived biochar as a valuable additive in AD systems. Optimizing biochar dosage, feedstock, pyrolysis temperature, and catalyst can significantly enhance methane production and process stability. Tailored biochar properties and production conditions offer promising opportunities for improving the efficiency and sustainability of AD systems.

Text

2024-06-19

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/88505

Chemical and Biological Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/