Abstract
The present study aimed to investigate the ability and efficiency of biological treatment to decontaminate pharmaceutical wastewater using indigenous and/or exogenous bacteria. One indigenous bacterium isolated from final effluent of the pharmaceuticals processing wastewater and five exogenous bacteria were molecularly identified and used as individual or mixed free-living cultures in a batch mode remediation process. Raw pharmaceutical effluents had high levels of all the tested parameters makes it one of the strongest industrial effluents. Treatment of pharmaceutical effluent for 6 d was time and bacterial species-dependent. Pseudomonas fluorescens (PF) was the most efficient in removing all the tested parameters except NO3 which increased due to oxidation of NH3 while Bacillus amyloliquefaciens (S1) and Bacillus cereus (L1) characterized by the lowest efficiency for contaminants removal. There was a general trend of increasing the removal efficiency (RE) of all parameters by all the tested bacteria with increasing the exposure time. However, bulk changes in all parameters were achieved within the first 24 h. The highest removals recorded were 94.63%, 79.44%, 75.07%, 81.03%, 90%, 93.75%, 55.2%, 94.29%, and 15.6% for total dissolved solids (TDS), total suspended solids (TSS), biochemical oxygen demand, chemical oxygen demand, fat, oil and grease (FOG), nitrate (NO3), ammonia (NH3), phenol, and total viable count of bacteria (TVC), respectively. Despite the highly efficient removals achieved for the tested parameters, their residual levels of all the parameters still above the maximum permissible limits for the safe discharge except FOG. Therefore, it is highly recommended to use the most promising bacteria in a fixed form to bring the effluent to the safe limits for the environment.