A free-piston batch reverse osmosis (RO) system for brackish water desalination: Experimental study and model validation

Batch RO is designed to achieve high energy efficiency and recovery in desalination. However, so far relatively few experiments on batch have been reported. Here we present an extensive experimental study of a single-acting, free-piston system using 8-inch spiral wound membrane. The was tested the laboratory with brackish feed water containing up 5 g/L NaCl. objective quantify performance terms Specific Energy Consumption (SEC), recovery, rejection, output. Sensitivity permeate flux recirculation flow rate also investigated. Performance compared against predictions theoretical model that accounts for salt retention, concentration polarization, longitudinal gradient module. For first time, osmotic backflow measured incorporated into model. concentrations ranging from 1 0.8, hydraulic SEC range 0.22–0.48 kWh/m3 electrical 0.48–0.83 kWh/m3. With improvements membrane permeability 4.4 8 LMH/bar, selection more efficient pumps, reduction valve friction losses, predicts will be lowered 0.14–0.39