Int.J.Curr.Microbiol.App.Sci (2013) 2(6): 137-145 137 Original Research Article Coupled ozonation with aerobic sequential batch reactor for treatment of distillery wastewater A.Vimala Ebenezer 1 , P.Arulazhagan 2 , J.Rajesh Banu 1 , S.Adish Kumar 1* 1 Department of Civil Engineering, Regional Centre of Anna University, Tirunelveli 627007, Tamil Nadu, India 2 Centre of Excellence in Environmental Studies, King Abdulaziz University, Jeddah, Saudi Arabia *Corresponding author e-mail: adish2002@yahoo.co.in ABSTRACT Introduction The wastewater released from distilleries is known as spent wash which contains huge quantity of dissolved organic matter, dissolved solids, suspended solids, colour along with other pollutants. Distillery spent wash is the unwanted residual liquid waste generated during alcohol production and pollution caused by it is one of the most critical environmental issue (Mohana et al., 2009). In the year 1999 there were 285distilleries in India producing 2.7x 10 9 L of alcohol and generating 4x10 10 L of wastewater annually. This number has raised to 319, producing 3.25x 10 9 L of alcohol and generating 40.4x10 10 L of wastewater annually (Uppal 2004). The contribution of distillery waste in India to organic pollution is approximately seven times more than that of the entire Indian population. Upon discharge into surface water, such a high value of organic contents are decomposed by microbial action leading to serious damage to aquatic life in consonance with depletion of dissolved oxygen (Nagaraj and Arvind kumar 2008). Also the highly coloured nature of spentwash can block out sunlight from rivers and streams thus reducing oxygenation of the water by photosynthesis and hence becomes detrimental to aquatic life (Radhika et al., 2010). Because of using large quantities of ISSN: 2319-7706 Volume 2 Number 6 (2013) pp. 137-145 http://www.ijcmas.com Keywords Distillery; spent wash; ozonation; wastewater; Advanced oxidation process (AOPs). The present study details the treatment of distillery spent wash by ozonation followed by aerobic treatment in a sequential batch reactor. Ozonation was carried out in different stages by varying flow rate, contact time, addition of H 2 O 2 and addition of Fenton's reagent. The ozonation at flow rate of 0.015 m 3 /min and contact time of 1 h followed by reaction with Fenton's reagent for 1 h achieved 81% and 75% removal of colour and COD. This effluent from ozonation is carried over to sequential batch reactor which gave a removal efficiency of colour and COD at overall 90% and 88% respectively. Treatment of distillery spent wash with aerobic sequential batch reactor alone achieved only 13% COD removal. .