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bioRxiv · 10.1101/2025.03.17.643612

Anaerobic co-digestion of sewage sludge and food waste: staging and carriers enhance system performance and process stability

Ali, M.·Pena, C. B.·De Vrieze, J.
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Abstract

Sewage sludge generated during biological wastewater treatment requires adequate treatment. Anaerobic digestion of sewage sludge is preferred, yet, it is often characterized by low biogas production rates. Co-digestion of sewage sludge with food waste could improve the hydrolysis rate and nutrients balance, resulting in higher biogas production rates. In this study, single- and two-stage anaerobic reactors were operated, with and without carriers in semi-continuous mode for 205 days for assessing the expected improved biogas production rates of sewage sludge and food waste co-digestion. Mono-digestion of sewage sludge resulted in average biogas production rates of 230{+/-}31 and 538{+/-}40 mLbiogas L-1 d-1 for single- and two-stage systems with carriers, respectively. Co-digestion of sewage sludge with food waste resulted in an improved biogas production rates in both systems. Average biogas production rates of 868{+/-}114 and 1507{+/-}174 mLbiogas L-1 d-1 were measured in single- and two-stage systems, respectively, with carriers during co-digestion of food waste (30%) and sewage sludge (70%). In all cases, the addition of carriers improved biogas production, and reduced volatile fatty acid accumulation. In conclusion, two-stage co-digestion of sewage sludge and food waste with carriers achieved the highest biogas production and long-term stability.

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Ali, M., Pena, C. B., De Vrieze, J.. 2025-03-17. Anaerobic co-digestion of sewage sludge and food waste: staging and carriers enhance system performance and process stability. https://doi.org/10.1101/2025.03.17.643612

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