Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong; Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Kowloon Tong, Hong Kong; Institute of Bioresource and Agriculture, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
J Environ Manage. 2021 Jul 15;290:112457. doi: 10.1016/j.jenvman.2021.112457. Epub 2021 Apr 22.
This work investigated the impact of the addition of different biochar types on mitigation of volatile fatty acid (VFA) accumulation, methane recovery and digestate quality in mesophilic food waste-sludge co-digestion. Four biochars derived from agricultural and sludge residues under different pyrolysis temperatures were compared. Specific biochar properties such as pH, surface area, chemical properties and presence of surface functional groups likely influenced biochar reactions during digestion, thereby resulting in a varying performance of different biochars. Miscanthus straw biochar addition led to the highest specific methane yield of 307 ± 0.3 mL CH/g VS versus 241.87 ± 5.9 mL CH/g VS from control with no biochar addition over 30 days of the co-digestion period. Biochar supplementation led to enhanced process stability which likely resulted from improved syntrophic VFA oxidation facilitated by specific biochar properties. Overall, a 21.4% increase in the overall methane production was obtained with biochar addition as compared to control. The resulting digestate quality was also investigated. Biochar-amended digester generated a digestate rich in macro- and micro-nutrients including K, Mg, Ca, Fe making biochar-amended digestate a potential replacement of agricultural lime fertilizer. This work demonstrated that the addition of specific biochars with desirable properties alleviated VFA accumulation and facilitated enhanced methane recovery, thereby providing a means to achieve process stability even under high organic loading conditions in co-digestions. Moreover, the availability of biochar-enriched digestate with superior characteristics than biochar-free digestate adds further merit to this process.
本研究旨在探讨不同类型生物炭对缓解中温条件下食物垃圾-污泥共消化过程中挥发性脂肪酸（VFA）积累、甲烷回收和消化液质量的影响。比较了四种不同热解温度下由农业和污泥残渣制成的生物炭。特定的生物炭特性，如 pH 值、表面积、化学性质和表面官能团的存在，可能会影响消化过程中的生物炭反应，从而导致不同生物炭的性能有所不同。添加芒草秸秆生物炭可使特定甲烷产率最高，达到 307 ± 0.3 mL CH/g VS，而不添加生物炭的对照样在 30 天的共消化期内的甲烷产率仅为 241.87 ± 5.9 mL CH/g VS。生物炭的添加提高了工艺稳定性，这可能是由于特定生物炭特性促进了协同 VFA 氧化。与对照样相比，生物炭的添加使总甲烷产量增加了 21.4%。还对消化液的质量进行了研究。添加生物炭的消化液富含大量的宏量和微量营养物质，包括 K、Mg、Ca、Fe，使添加生物炭的消化液成为农业石灰肥料的潜在替代品。这项研究表明，添加具有理想特性的特定生物炭可以缓解 VFA 积累，并促进甲烷回收的增强，从而为共消化过程中即使在高有机负荷条件下实现工艺稳定性提供了一种方法。此外，生物炭丰富的消化液具有优于无生物炭消化液的特性，这为该工艺增加了更多价值。
