Pre-treatment of ammonia-nitrogen (NH_3–N) removal from scheduled waste leachate by air stripping

摘要

The effect of lime dosage, pH and air flow rate on the removal process of NH3-N from a scheduled waste landfill leachate was investigated by using a lab-scale air stripping column. The main objectives were to reduce NH3-N concentration prior further biological treatment and to investigate factors affecting air stripping processes. A central composite design (CCD) of response surface methodology (RSM) was employed to optimize the parameters affecting NH3-N removal from the leachate. It was observed that the optimal conditions obtained from desirable response (NH3-N removal) were predicted at lime dosage of 9.8 g L-1, pH = 11 and air flow rate of 2.25 L min(-1). Quadratic RSM predicted the maximum NH3-N removal to be 96.5% at these optimal conditions and concurred with the experiments which successfully removed 96.3% of NH3-N within 24 h. This study shows that the RSM could successfully predict the degree of NH3-N removal. The findings suggest that RSM approach was feasible for optimizing the air stripping process for NH3-N removal from scheduled waste landfill leachate in laboratory scale. Based on the obtained results, air stripping process can be used as an efficient pre-treatment for removal of NH3-N in scheduled waste leachate.