RESUMEN
Aims/objectives: The cognition about microbial population of activated sludge and their treatment potential will be very useful for industrial wastewater treatment plant operation. Methodology: In this study microbial population of activated sludge process that was used for pharmaceutical wastewater has been investigated. Sampling was done from return sludge line and after serial dilution 1500 plates were studied. Methods for separating the bacteria from wastewater was pour plate method. All bacterial samples were purified using nutrient Agar and Macconkey Agar culture. Bacteria were separated from return sludge line and classified into 3 groups after biochemical tests and morphological analysis, These include positive bacteria of Bacillus genus, Pseudomonas aeruginosa and Flavobacterium. Results: The biodegradability study on pharmaceutical effluent using identified cultures in laboratory scale showed that Bacillus spp. are the most efficient bacteria for organic matter degradation. Conclusion: Results of this study showed that providing a microbial bank of these spp. can be useful for resistant operation of activated sludge.