Evaluation of operational performance in an integrated RO and RED hybrid desalination process using lava seawater

An integrated RO and RED hybrid process using lava seawater was evaluated in a pilot plant, confirming its effectiveness in reducing energy consumption and improving water quality. Two RO membrane modules were tested, LG SW 400 R and Vontron SW8040XLE-400, under varying operating pressures using both lava seawater and RED-treated water as feed. Lava seawater, naturally filtered through volcanic bedrock, exhibited lower salinity and a stable temperature, which contributed to reduced osmotic pressure compared to conventional seawater. Experimental results demonstrated that the RO process with lava seawater achieved comparable recovery and stable production TDS at relatively lower operating pressures and energy consumption than those of commercial RO processes. The hybrid RO process attained a flux recovery rate of approximately 40 %, with SEC values ranging from 2.412 to 3.062 kWh/m 3 , representing significant energy savings over stand-alone RO processes. Performance comparisons revealed that the LG SW 400 R module provided superior water quality with lower permeate conductivity, while the Vontron SW8040XLE-400 module delivered better energy efficiency. These findings indicate that the RO hybrid process not only reduces overall energy consumption but also improves operational stability and product water quality.