ABSTRACT
Nitrate pollution has been universally recognized to have a plethora of negative effects on human health. Several treatment methods, with different performance levels, are available for drinking water treatment to reach World Health Organization (WHO) standards, but the most economical process has been biological denitrification. The heterotrophic biological denitrification (HBD) technique is finding more applications due to its cost-effectiveness. The process has significant dependence on temperature, inlet nitrate concentration, flow rate through the reactor, and the microbial strain used. The present work investigated the removal of nitrate using Pseudomonas stutzeri (NCIM 5136) as the microbial strain. Optimization of process variables, i.e., temperatures and flow rates, for nitrate removal using central composite design (CCD) with cotton as the carbon source was done, and a second-order polynomial model was obtained. The R2 value was 0.933, showing that the values predicted by the statistical design model were in good agreement with experimental values. The model also predicted the maximum denitrification of 598.462 mg/day at a flow rate of 5 ml/min and 40°C temperature with the strain Pseudomonas stutzeri (NCIM 5136). The polynomial model developed by the software was proved to be statistically valid by giving good correlation between the predicted and experimental values.
