Comparative evaluation of nanofiltration and reverse osmosis treatment of an effluent from dairy industry

Abstract

Abstract Nanofiltration (NF) and reverse osmosis (RO) membranes were evaluated for the treatment of the effluent of chemical‐biological treatment plant and the original effluent of dairy industry, respectively. A thin film composite type of spiral wound membrane (2 m2 area) with the NF (TFC‐S) and the RO (TFC‐HR) was used. The runs were conducted at approximately 16 and 30 % water recovery of a single membrane at different pressures and flowrates for the RO and NF, respectively. Permeate flux declined rapidly at the beginning of the run and then appeared to remain approximately constant after 50 h of operation at different pressures. At a pressure of 10 bar, the permeate fluxes of the NF and RO decreased from 46 l/m2h to 23 l/m2h after 88 h of operation and from 21 l/m2h to 10 l/m2h after 68 h of operation, respectively. The specific energy consumption increased as a function of time and decreased with increasing pressure for each membrane. The average specific energy consumption was obtained at 6 and 10 ...