Effect of Pressure on Alginate Fouling in Forward Osmosis

The superior fouling resistance of forward osmosis (FO) desalination with respect to reverse osmosis (RO) has prompted debate over the effect of hydraulic pressure. We present a method of isolating the effects of pressure from other differences (e.g., internal concentration polarization) between FO and RO: pressurizing the entire FO module. This method revealed no evidence of foulant compaction and no decline in cleaning performance at elevated pressures as high as 40 bar. In contrast to previous findings, we conclude that low pressure does not contribute to the fouling resistance of FO.