Optimization and kinetics studies on biodegradation of atrazine using mixed microorganisms

In this work, degradation of atrazine was carried out in batch reactors using mixed microorganisms obtained from pharmaceutical wastewater sludge. The effects of process parame- ters like pH, temperature, inoculum concentration, and agitation speed on atrazine degradation were studied and optimized using response surface methodology (RSM). The optimum condition for the maximum degradation of atrazine was pH – 6.7, temperature – 29.3 °C, inoculum concen- tration – 5%, and agitation speed – 137 rpm. At these conditions, the effect of atrazine concentra- tion was studied. From the results, it was found that increase in atrazine concentration decreases the degradation efficiency. The maximum atrazine degradation was found to be 94.4%. Various cell growth models and substrate inhibition models were used to describe the atrazine degradation kinetics. From the results, it was found that Haldane model fits the data well with R² value of 0.9001.