Physico-chemical Treatment of Wastewater From Clusters of Small Scale Cotton Textile Units

Abstract

Small scale industries can not own individual wastewater treatment facility due to non-availability of land and skilled manpower for operation and maintenance of wastewater treatment plants. A centralized wastewater treatment facility for clusters of small scale industries is appropriate. This concept is gaining popularity in recent years. In India, various textile process operations are undertaken by individual small scale units. The wastewater generated at these units is conveyed to a common effluent treatment facility comprising of equalization, flocculation-clarification, activated sludge process, secondary clarification and finally discharge into inland surface water bodies. The wastewater from small scale cotton textile processing units was highly coloured and alkaline with average BOD and COD concentration of 205 and 790 mgl−1, respectively. Due to the presence of several dyes, particularly reactive dyes, the biological treatment is often found less effective. Therefore, applicability of various physico-chemical treatment methods needs to be investigated in pursuit of an alternative to biological treatment of textile wastewater. A physico-chemical treatment scheme, involving chemical coagulation-sedimentation, dual media filtration, activated carbon adsorption followed by chemical oxidation was investigated in this paper. The quality of final treated wastewater in terms of BOD and COD was 18-24 and 230-240 mgl−1, respectively through this scheme. A scheme of treatment comprising coagulation-sedimentation, dual media filtration, activated carbon, chemical oxidation may be considered as an alternative to biological treatment of textile wastewater.