Physiochemical treatment of textile industry effluents

The study mainly focuses on the application of chemical coagulants (lime,alum and ferrous sulfate) and advanced oxidation processes (aops) (ozone treatment and fenton process,alone and in combination) to treat textile industry effluents,optimization of coagulation process for various coagulants in terms of process conditions,including coagulant dose,ph and settling time. the results revealed that alum was most effective. the efficiency of coagulation process was dose dependent and 400 mg/l dose of alum alone showed maximum color removal of 47%,57% and 54% of yellow,red and blue dyes,respectively in addition to the cod removal of 44%. the combined applications of alum and lime (300:75 mg/l) and lime and alum (300:75 mg/l) showed slightly better cod removal of 51%. however,color removal efficiency of all coagulants was at par. the ozonation process appeared the most promising for the treatment of waste water and color/cod removal,the efficiency of which increased with increasing the treatment time at constant ozone dose. for less polluted effluents,97% color removal was obtained after 1 minute and after 15 minutes for highly polluted effluents; the cod removal efficiency of the process for less polluted effluents was around 89% after 5 minutes ozonation and for highly polluted effluents 88% cod removal after 40 minutes. the performance of fenton process was extremely low as compared to ozonation process. increase in ph,significantly decreased the color removal efficiency of the process. cod removal efficiency of fenton process increased with an increase in settling time.