Abstract: Sludge dewatering remains a global environmental challenge in wastewater treatment. Fenton conditioning technology has attracted widespread attention for its exceptional dewatering efficiency, while significant quantities of iron-rich sludge has been generated during the process, which requiring sustainable management solutions. To address this issue, a new process of iron-rich biochar sludge conditioning and dewatering-land application has been developed in the previous study. Taking this new process as the research object, Life Cycle Assessment (LCA)method was used to analyse the environmental impacts. The research results showed that compared with the Fenton red mud sludge conditioning and dewatering-landfill process, the new process has significantly improved the five types of environmental impacts, namely global warming potential, acidification potential, eutrophication potential, inhalable inorganic substances and ecotoxicity, which were reduced by 75.12%, 44.26%, 4.96%, 22.86% and 63.92%, respectively. Through standardized calculation of various environmental impact results, it was found that the total environmental impact potential value of the new process could be reduced by 25.89%, indicating that the new process of pyrolysis and resource utilization of iron-rich sludge has better environmental benefits.

Key words: sewage sludge, Fenton conditioning technology, sludge recycling, iron-rich sludge biochar, life cycle assessment