A multi-objective optimization approach for holistic planning of the water system in dry bulk ports: integrating life cycle assessment and life cycle costing

Abstract

The increasing throughput of dry bulk ports is continuously escalating the demand for freshwater, challenging water resource management and port sustainability. Utilizing unconventional water resources is a potential solution, but the planning of water system designed to realize the efficient utilization of unconventional water resources in dry bulk ports remains poorly investigated. This study proposed a multi-objective optimization approach integrating life cycle assessment and life cycle costing for holistic planning of the water system. It considered environmental, economic, and social objectives while incorporating decision-makers' preferences. The utilization rate of unconventional water resources (URUWR), defined as the ratio of unconventional water resource utilization to total water consumption in ports, was regarded as the social objective. Huanghua Port was chosen as a case study. The results showed that the optimized schemes improved economic and environmental performance over the current scheme, while maintaining the URUWR ≥90 % (the development target for Huanghua Port). Specifically, prioritizing economic objectives reduced costs by 15.89 %–16.04 %, while prioritizing environmental objectives decreased environmental impact by 43.09 %–44.21 %; balancing both objectives achieved a 7.14 % cost reduction and a 20.11 % decrease in environmental impact. Contribution analysis revealed that optimizing the external water supply system was crucial for improving both objectives. Regarding cost-effectiveness, internal unconventional water resources were more advantageous and should be prioritized for development.