Membrane desalination of ballast water using thermoelectric energy from waste heat

Ballast water management and treatment is an on-going issue for marine industry including small and bulk carriers, cruise ships, passenger ships and cargo vessels. Several regulations are implemented at regional, national and international levels to minimise the environmental impacts related to improper disposal of contaminated ballast water at ports. In this study, an environmentally benign approach for managing the ballast water on marine vessels is proposed. Thermoelectric energy harvested from main engine’s waste heat is considered as a primary source of energy for a reverse osmosis desalination process, which recovers the ballast water in the form of clean water to provide for fresh water supplies in ships. A case study is presented to elaborate the proposed scheme. The effects of seawater temperatures and energy recovery schemes on the freshwater production rates are also discussed. The proposed scheme provides a promising approach to ballast water management while allowing to provide in situ treatment for its beneficial use in shipping operations.