C.o.d Reduction of Reactive Dyeing Effluent from Cotton Textile Industry

The present study focuses on the improvement in the effluent treatment for the effluent generated from a cotton textile industry employing three reactive dyeing methods viz., Exhaust method, Pad-Dry-Cure method, and Pad-Batch method. Stabilisation pond, aeration tank, and aerobic biological treatment (using E-Coli type bacteria) are simulated in the laboratory in a series operation. Results revealed an overall COD reduction of 80%, 90%, and 62% respectively for the effluent generated from each of the three above mentioned reactive dyeing methods. A subsequent polishing treatment with activated carbon can further bring down the COD levels of the effluents from the three reactive dyeing methods to well below 250 mg/L, which is the upper limit for disposal of effluents into surface water. A flow diagram incorporating the results of present study and the polishing treatment technique is proposed for better results.