Treatment Of Biologically Treated Distillery Effluent - A Case Study

Abstract

The paper addresses physico-chemical treatment of biologically treated distillery effluent using conventional and non-conventional coagulants. Conventional coagulants, viz. ferrous sulphate, ferric sulphate, and alum were used during the study. Ferrous sulphate in combination with lime was found to be optimal which could remove 78.50 percent COD with efficient removal of colour. Further, commercially available polyelectrolyte aid, Percol 47 was found to be suitable for the reduction of ferrous sulphate requirement from 20 gL −1 to 10 gL −1 , which produced the same quality of effluent without affecting the overall efficiency of the treatment. Non-conventional coagulants viz. wastewater from an iron pickling industry and titanium ore processing industry were also evaluated. The iron pickling wastewater also removed 86.8 percent and 92.5 percent residual COD and BOD, respectively, from the biologically treated distillery effluent. Further, commercial activated carbon was assessed for polishing the effluent after treatment with coagulants. A dose of 8 gL −1 of carbon with contact time of 45 minutes was found to be optimal. The effluent generated after treatment with activated carbon had COD concentrations less than the discharge standard for inland surface water as prescribed by Central Pollution Control Board (CPCB), Ministry of Environment and Forests (MOEF), Government of India.