Influence of draw solution type and properties on the performance of forward osmosis process: Energy consumption and sustainable water reuse

Abstract

Single and multi-component fertilizers were used as a draw solution (DS) in forward osmosis (FO) to produce high-quality water from synthetic and seawater solution, eliminating the need for DS regeneration and reducing the operational energy. The effect of DS type, concentration, circulation flow rates on the FO water flux (WF), specific water flux (SWF), percentage water recovery (%Wrecovery), reverse salt flux (RSF) and percentage salt rejection (%R) were studied. The results showed that single fertilizer draw solution (SFDSs) produced higher WF (4.43 L/m2.h), %Wrecovery (30%) and RSF (60%) in comparison with multi-component draw solution (MCDS) with WF, %Wrecovery and RSF of 2.57 L/m2.h, 17% and 46%, respectively. DS with higher concentration produced the highest SWF and %Wrecovery and consumed less energy. MCDS with concentration of 200 g/L showed SWF in the range of 14.0 to 10.4 L/m2h and energy consumption of 0.312 kW/h m3 in comparison with 10 to 7.8 L/m2h and 0.23 kW/h m3 for MCDS with concentration of 100 g/L. Increasing the recirculation flow rate showed minimum effect on WF and up to 35% energy saving. Pure water extracted using liquid fertilizers utilizing the unique FO mass transport properties balanced nutrient requirement and the water quality parameters, thereby sustaining the aquaponics industry. - 2019 Elsevier Ltd