Studies in nanofiltration of dyes industry effluent

A large number of chemicals are being produced in the industries, which resulted in accumulation in the effluent stream. The impact of these effluents on the environment is very adverse, if it released directly without treatment. Nowadays, the treatment of the effluent before discharge is very important due to strict norms imposed by various government agencies. In our study, the effluent from a local effluent treatment plant (effluent from dyes factory) was procured and treated with hydrophilic polymeric and ceramic nanofiltration membranes. The membrane characterisation was done based on flux, permeability, flux recovery ratio, and flux decline ratio. The effluent received from ETP and treated effluent was characterised in terms of pH, total dissolved solids (TDS), Chemical Oxygen Demand (COD), Conductivity, Turbidity, and Osmolality. From our experimental study, more encouraging results were obtained. More than 50% COD reduction was observed in the process. The membrane flux was recovered by the physical (by using backwashing) and chemical process (by using sodium hypochlorite solution). The different range was used for optimising the appropriate process for recovery of membrane flux. About 95% membrane flux was recovered by physical process on both ceramic and polymeric membranes.