Tannin degrading microbes Bacillus laterosporus MTCC 6017, Klebsiella pnuemoniae MTCC7162 and Pseudomonas aeruginosa isolated from tannery effluents were tested for their ability to degrade vegetable tannins in tannery effluents, along with other polluting parameters in the effluents like COD and Total Dissolved Solids (TDS). An inexpensive Air-Lift Reactor (ALR) was designed to carry out effluent treatment (321) at a pilot scale. The efficiency of the ALR on the reduction of COD, tannin and TDS by the consortium of microorganisms was assessed at different air flow rates (0.1 l/s to 1.5 l/s) and three diluted loading rates (1: 5 to 1: 15). The optimum AFR rate was found to be between 0.5 and 1.0 l/s, to get significant result in 48 h. Reduction in the loading rates by means of dilution (1:5) enhanced the performance of the isolates under ALR, reduction increased to 87%, 89% and 549% for COD, tannin and TDS respectively at the end of 48 hours. © Enviromedia Printed in India. All rights reserved.