Forward Osmosis Process for Concentration of Treated Tannery Effluent

Forward Osmosis is a suitable pretreatment process for reverse osmosis for secondary-treated sewage reuse and secondary-treated industrial effluents. In this study, the FO process is investigated for concentrating synthetic secondary treated tannery effluents using 24 g.L-1 and 38 g.L-1 of NaCl solution as draw solution. Results showed that 38 g.L-1 NaCl solution when used, provided higher flux and lower flux decline ratio as compared to 24 g.L-1 NaCl solution. The solute rejection by FO membrane was more in FO experiments using 38 g.L-1 NaCl solution as DS as compared to 24 g.L-1 NaCl solution. Contact angle, Fourier transform infrared spectroscopy, and scanning electronic microscopy tests on pristine and chemically cleaned membranes indicated the change in membrane structure and the presence of foulants on the membrane surface, indicating insufficient chemical cleaning. Findings signify implications on the concentration of DS and the cleaning method adopted for concentrating treated tannery effluent efficaciously using the FO process.