Centre for Water Technology (WATEC), Department of Biological and Chemical Engineering, Aarhus University, Universitetsbyen 36, 8000, Aarhus C, Denmark.
Centre for Water Technology (WATEC), Department of Biological and Chemical Engineering, Aarhus University, Universitetsbyen 36, 8000, Aarhus C, Denmark.
J Environ Manage. 2023 Dec 15;348:119046. doi: 10.1016/j.jenvman.2023.119046. Epub 2023 Oct 11.
Sewage sludge management poses challenges due to its environmental impact, varying composition, and stringent regulatory requirements. In this scenario, hydrothermal liquefaction (HTL) is a promising technology for producing biofuel and extracting phosphorus from sewage sludge. However, the toxic nature of the resulting process water (HTL-PW) raises concerns about integrating HTL into conventional wastewater treatment processes. This study investigated the inhibitory effects of HTL-PW on the activity of the main microbial functions in conventional activated sludge. Upon recirculation of the HTL-PW from the excess sludge into the wastewater treatment plant, the level of COD in the influent is expected to increase by 157 mgO⋅L, resulting in 44% nitrification inhibition (IC of 197 mg⋅L). However, sorption of inhibitory compounds on particles can reduce nitrification inhibition to 27% (IC of 253 mg⋅L). HTL-PW is a viable carbon source for denitrification, showing nearly as high denitrification rates as acetate and only 17% inhibition at 157 mgO⋅L COD. Under aerobic conditions, heterotrophic organic nitrogen and organic matter conversion remains unaffected up to 223 mgO⋅L COD, with COD removal higher than 94%. This study is the first to explore the full integration of HTL in wastewater treatment plants for biofuel production from the excess activated sludge. Potential nitrification inhibition is concerning, and further long-term studies are needed to fully investigate the impacts.
污水污泥管理由于其对环境的影响、组成的变化和严格的监管要求而带来挑战。在这种情况下，水热液化 (HTL) 是一种从污水污泥中生产生物燃料和提取磷的有前途的技术。然而，产生的工艺水 (HTL-PW) 的毒性引起了将 HTL 整合到传统废水处理工艺中的关注。本研究调查了 HTL-PW 对常规活性污泥中主要微生物功能活性的抑制作用。当将 HTL-PW 从剩余污泥回流到废水处理厂时，进水的 COD 水平预计将增加 157mgO⋅L，导致硝化抑制 44%（IC 为 197mg⋅L）。然而，抑制化合物在颗粒上的吸附可以将硝化抑制降低至 27%（IC 为 253mg⋅L）。HTL-PW 是反硝化的可行碳源，其反硝化速率与乙酸几乎相同，在 157mgO⋅L COD 时仅抑制 17%。在好氧条件下，异养有机氮和有机物转化在高达 223mgO⋅L COD 的条件下不受影响，COD 去除率高于 94%。本研究首次探索了从剩余活性污泥中生产生物燃料，将 HTL 完全整合到废水处理厂中的情况。潜在的硝化抑制令人担忧，需要进一步进行长期研究以充分调查其影响。
