Life cycle assessment of the Pingjiang River water purification project in Suzhou

ABSTRACT This study presents the Pingjiang River Water Purification Project in Suzhou, a historic city facing water quality challenges due to urbanization. The project integrates advanced physical treatment techniques to restore water quality and ecological health while preserving the city's cultural heritage. The core component, the water purification plant, employs hollow-fibre ultrafiltration membrane technology to treat river water, achieving significant reductions in turbidity, suspended solids, total phosphorus, and chroma, along with improved transparency. Additionally, the plant's underground layout minimizes the land footprint, while sludge generated through the process is repurposed for brick manufacturing, supporting resource recovery. This study conducts a life cycle assessment to evaluate the environmental impacts of the plant's water purification process. Results show that electricity consumption, polyaluminium chloride, and sodium hypochlorite are the top contributors to environmental impacts, with a global warming potential of 0.207 kg CO2 eq/m3. However, the plant also offsets impacts through phosphorus removal and sludge reuse. Recommendations include optimizing chemical inputs, improving energy efficiency, and integrating renewable energy. The findings highlight the project's role in balancing water quality improvement with environmental tradeoffs and co-benefits, providing insights for sustainable urban river restoration in culturally significant contexts.