Technology development of membrane filtration for reactive dye removal from textile industries effluents

Effluents from textile industries contain different types of dyes. One of these dyes used in textile industries is Reactive dye. Because of high molecular weight and complex chemical structures, they show low levels of biodegradability. Hence, the direct disposal of these effluents to municipal wastewater treatment, produce problems in biological treatment processes. The aim of this research is to study the efficacy of membrane filtration process for reactive dye removal from textile industries effluents. In the first step, reactive dye biodegradability was studied through Zahen-Wellens method (ISO9888 1999). In the second step, four types of reactive dyes in 80, 100, 250, 500 and 1000 mg/L concentrations passed through spiral wound membrane modules of nanofilter (NF)with a molecular weight cut off (MWCO)of 300 and 600 dalton(Da) and reverse osmosis(RO) of 50 Da in different temperatures and pressures. In each step, permeate flux, rejection coefficient and ADMI (American Dye Manufacturer Institute) value were determined. Chemical Oxygen Demand (COD) and rejection coefficient (R%) for reactive dye was 25 and 12. 5 reactively. For NF 300, NF600 and RO, COD and R% were obtained (33%, 36%), (33%, 29%) and (45%, 99. 6%) respectively. The optimum operating condition of 30-35 oC temperature and 4 bar pressure for NF300 & 600Da and 7bar for RO were obtained. according to obtained results, concentration havent any effect on membrane performance. Results also clearly showed higher removal efficiency for the membrane treatment than for biodegradability studies.