Renewable energy driven desalination processes with zero liquid discharge: System analysis and experimental assessment

Current global initiatives increasingly aim to promote environmentally sustainable processes, combining net-zero energy systems with activities that minimize the ecological impact. In this context, desalination is an attractive solution to water scarcity, but it faces as main challenges high energy consumption and brine generation. To address these issues, this study proposes technical methods to design renewable energy sources systems integrated into zero liquid discharge processes. The experimental prototype includes units, reverse osmosis, cooling tower, mechanical vapor compression, and wind-aided intensified evaporation. Solar photovoltaic and biomass energy sources cover thermal and electrical demand requirements. The theoretical analysis is evaluated through a real case study located in the South-East of Spain. Results show a global electricity consumption of 29 kWh/m 3 freshwater. The photovoltaic self-sufficiency system supplies 67% of the annual demand, though this percentage depends on monthly solar irradiance. The rated power of the PV system is also selected based on the surplus ratio (annual average of 19.81%), resulting in a 35 kWp installation. Moreover, the thermal demand is covered by biomass resource, requiring 64 kWh and enabling the evaporation of 50% of the feed stream. The environmental impact of these renewable solutions leads to a reduction in gas emissions of 77% to 84%, depending on the conventional energy sources replaced. • The feasibility of renewable energy in zero liquid discharge processes is evaluated. • Parametric analysis of the photovoltaic power potential is performed. • The photovoltaic self-sufficiency system supplies 67% of the annual demand. • The biomass boiler allows 50% evaporation of the brine stream. • Carbon footprint is reduced by 77–84% from conventional sources.