The article discusses the challenge of managing waste-activated sludge (WAS) generated during water treatment processes and the limited conversion efficiency of various treatment methods. The study introduces an innovative solution using biochar-enhanced polyhydroxyalkanoates (PHA) biosynthesis to maximize the utilization of WAS resources. By using biochar derived from residual sludge as a catalyst, the system achieved an 81.04% increase in PHA synthesis efficiency during anaerobic digestion without requiring additional carbon sources or specialized bacteria. This approach offers a sustainable and practical solution for wastewater treatment, emphasizing environmental protection and resource development. The research demonstrates the successful application of biochar in enhancing PHA production, potentially addressing the challenges associated with WAS management and providing a pathway towards more efficient and sustainable water treatment practices. The study's findings support the development of innovative technologies for transforming waste products into high-value materials, contributing to waste reduction and environmental sustainability.