Surface water treatment for production of potable water by coagulation/filtration/nanofiltration membranes hybrid system.

Abstract

Providing potable water will be a challenge for humanity over the next years. In this research, water samples from the Gamasiab River (Iran) were purified to achieve drinking water by applying coagulation, conventional filtration in combination with the nanofiltration process. By using poly aluminum chloride as a coagulant, the turbidity decreased by 96.4%. The turbidity and COD decreased by 98.82% and 32.7%, respectively, via passing the effluent through the activated carbon. Membranes were made of polyethersulfone (PES). Cesium hydrogen phosphotungstic acid (Cs0.5 H2.5 PW12 O40 as CsPW) nanoparticles were incorporated into the polymer matrix to improve the hydrophilicity. The morphology of membranes was studied using the FE-SEM and AFM. The pure water flux and contact angle for the sulfonated PES with 1.5 wt.% CsPW were 51.9kg/m2 h and 55.49 °, respectively. The percentage of the turbidity, conductivity, TDS, and COD removal was found to be 99.9, 89.3, 89.3, and 86.6%, respectively, after the hybrid process. The removal of calcium, magnesium, nitrate, chloride, sodium, sulfate, and bicarbonate ions was 90.5, 83.4, 87.9, 60.7, 49, 86, and 80.5%, respectively. Based on these results, the river water meets the standards for drinking water after being purified by applying the aforementioned coagulation/filtration and nanofiltration processes. PRACTITIONER POINTS: The treatment of the Gamasiab River (Iran) was selected for this study to produce potable water. A hybrid systematic coagulation/filtration/nanofiltration (NF) was considered. Water quality parameters were measured and compared with the standard values. The cesium hydrogen phosphotungstic acid was incorporated into the NF to increase the hydrophilicity and water flux. Polyethersulfone was sulfonated to add the sulfonyl group to the polymer.