Treatment of Ammonia Nitrogen Wastewater by Box-Behnken Optimized Bubble Discharge Plasma

Abstract

In this study, the Box-Behnken design model was used to plan the experiment, and the corresponding model was constructed using Design Expert software. Using this model, the interaction of various factors in the treatment of high-concentration ammonia nitrogen wastewater using bubble discharge plasma was investigated. Response surface model analysis and regression equation significance tests were conducted to optimize the treatment conditions for high-concentration ammonia nitrogen wastewater treated by plasma. Based on the single-factor test results, voltage, frequency, and air pressure were selected as the influencing factors, the removal rate of ammonia nitrogen was taken as the target value, and the response surface was analyzed. The results revealed the influence of the interaction between these factors on the removal rate of ammonia nitrogen, and determined the optimal reaction conditions: voltage 12.1 kV, frequency 165.9 Hz, pressure 0.01 MPa; under these conditions, the 50 min treatment rate of ammonia nitrogen reached 99.14%. Subsequently, these conditions were validated and their high efficiencies were demonstrated through degradation kinetics.

Keywords: Response surface analysis, Plasma, Bubble discharge, Degradation kinetics, NH3-N, Wastewater treatment