Comparative study of the effect of loading increments on the mesophilic codigestion of waste activated sludge and food waste: Reactor performance, stability analysis, and microbial community

• Published in: Chemosphere (Oxford) 2022-12, Vol.308, p.136308-136308, Article 136308
• Main Authors: Xing, Bao-Shan, Tang, Xi-Fang, Wang, Ru, Cao, Sifan, Wen, Junwei, Zhang, Yi, Chang, Xiang-Lin, Wang, Xiaochang C., Chen, Rong
• Format: Article
• Language: English
• Subjects: Codigestion; Food waste; Loading increments; Loading rate; Methanosarcina; Waste activated sludge
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2022.136308

The performance and stability of mesophilic codigestion of waste activated sludge (WAS) and food waste (FW) were compared in two parallel, continuously stirred tank reactors using high- and low-magnitude loading increments for the loading regimes. The results indicated that a high methane (CH4) production of 6.98 L L−1·d−1 was realized without volatile fatty acid accumulation via low-magnitude loading increments at a high loading of 26.5 g-COD·L−1·d−1, and this system was more stable and achieved a higher efficiency than the codigestion system that used high-magnitude loading increments at similar loading and operating conditions. Furthermore, higher CH4 yields of 258–334 mL-CH4·g-COD−1, TCOD removal efficiencies of 64–79%, conversion ratios of 62–88%, and methanogenic activities of 0.37–0.40 g-CH4-COD·g-VS−1·d−1 were consistently maintained via the low-magnitude loading increments during the high-rate period. High abundances of the phyla Firmicutes (63.3%) and genus Methanosarcina (94.5%) contributed to the high rates and stable operating conditions of the mesophilic system for WAS and FW codigestion using low-magnitude loading increments. [Display omitted] •Two CSTR codigestion systems with different incremental loadings were compared.•Low-magnitude loading increments can lead to stable and high rates of codigestion.•A high abundance of Methanosarcina was induced via low-magnitude loading increments.•Low-magnitude loading increments provides an easy-to-apply and promising approach.