Int. J. Environment and Pollution, Vol. 32, No. 1, 2008 43 Copyright © 2008 Inderscience Enterprises Ltd. Treatment of distillery anaerobic effluent in a hybrid biological reactor Debabrata Mazumder* Civil Engineering Department, Bengal Engineering and Science University, Howrah 711103 (WB), India E-mail: debabrata@civil.becs.ac.in *Corresponding author Somnath Mukherjee Civil Engineering Department, Jadavpur University, Kolkata 700 032 (WB), India E-mail: snm_ju@yahoo.co.in Pradip K. Ray Civil Engineering Department, Bengal Engineering and Science University, Howrah 711103 (WB), India E-mail: pradipkumarray@hotmail.com Abstract: The treatability of anaerobic effluent from a molasses-based distillery was studied in a shaft-type hybrid bioreactor under purely suspended growth and hybrid system containing 5 mm tyre-tube beads. The Ks, k, Y and k found as 111.29 mg/l, 0.026/h, 0.4607 and 0.0040/h respectively. The maximum COD removal was 51.7% at a loading rate of 5.250 kg d –1 m –3 . The overall removal rate was 0.0431, 0.0452, 0.0484 and 0.053/h under 0, 10, 20 and 30 g/l of beads respectively. When attached biomass increased, the cell synthesis part of oxygen utilisation coefficient gradually decreased and that for endogenous respiration increased. Keywords: activated sludge; hybrid bioreactor; shaft-type; tyre-tube beads; distillery wastewater; post-anaerobic effluent. Reference to this paper should be made as follows: Mazumder, D., Mukherjee, S. and Ray, P.K. (2008) ‘Treatment of distillery anaerobic effluent in a hybrid biological reactor’, Int. J. Environment and Pollution, Vol. 32, No. 1, pp.43–56. Biographical notes: Debabrata Mazumder graduated in 1993 with Bachelor of Civil Engineering from Jadavpur University. He obtained his Masters in Civil Engineering with specialisation in environmental engineering from the same university in 1996. He received his PhD in Civil Engineering from Bengal Engineering and Science University, Shibpur (BESUS), in 2004. Now, he is a Lecturer in Civil Engineering Department of BESUS. In 2003, he became a Senior Lecturer in the same department. He has published 30 papers in various national and international journals and conferences.