An environmental and economic sustainability assessment of a pressure retarded osmosis system

Abstract

Desalination can meet increasing water demands, but results in high energy consumption and the discharge of highly concentrated brine. Pressure retarded osmosis (PRO) can serve as an efficient energy recovery technology for desalination with the potential to address these challenges. This study provides an environmental and economic sustainability assessment on a hypothetical full-scale PRO system by performing a life cycle assessment (LCA) and a life cycle cost analysis (LCCA). In this hypothetical case study (in Tampa, Florida, USA), the amount of recovered energy impacted most LCA categories, indicating that the overall environmental impact would be lowered when integrated with a desalination plant. The levelized cost of energy (LCOE) ranged from 0.62 $(kWh)−1 to 0.69 $(kWh)−1 depending on the feed water source. Compared to wind power and photovoltaics, the PRO system was highly environmentally competitive due to low GHG emissions, but the baseline design was not found to be economically competitive. Lowering the LCOE would be possible when the feed solution comes from a wastewater treatment plant within 1 km and when high-quality treated wastewater is used to avoid pretreatment; this design achieved an LCOE of 0.14 $(kWh)−1. Future research is recommended on membrane advancements and maintenance improvements for fouling mitigation.