Ultra-Nano Filtration: A Promising Practice to Supply Potable Water from Surface Resources

Abstract

Membrane technology has grown rapidly in Iran in the last decade, however most of the installed capacities are to produce industrial water and rarely for potable water. Most of the installed plants use RO process to produce industrial and even potable water. In this study, Nanofiltration (NF) technology was employed for Karoon River desalination as an economic and energy saving treatment process. Unstable quality and high turbidity of Karoon River results in fouling on NF/RO membranes, leading to chemical washing once a month and replacing membranes within 6 month or per year. Thus, unlike of many water treatment plants which benefit traditional pretreatment processes; ultra-filtration (UF) has been used as an effective and helpful pretreatment process. To make the proposed system reliability more clear, UF-NF results after three month of operation were compared with an equivalent RO system. In fact, UF-NF system benefits a lower pressure drop due to lower fouling on membranes and also more suitable permeate quality for drinking than RO. Hence, the promising results of the present practice may offer a reasonable solution to solve potable water supply problems in some deprived and arid regions.