Optimization of landfill leachate treatment by microwave oxidation using the Taguchi method

Abstract

Landfill leachate issue in Taiwan was often to be concerned for its treatment technology, effects, and costs. An experimental study using microwave oxidation process to treat leachate was designed and optimized using Taguchi L16 orthogonal array (OA) design, coupled with the signal-to-noise (S/N) ratio method and the analysis of variance (ANOVA) method, and compared the relationships between them. Three experimental factors, microwave (MW) power settings, persulfate (PS) doses, and MW irradiation time (T), as well as three target parameters, total organic carbon (TOC), color, and UV254, were studied. The optimal conditions were found to be: 550 W, 1 M, and 120 min for TOC removals of 80% and color removals of 96%; 775 W, 1 M, and 120 min for UV254 removals of 55%. The ranking of significance of experimental factors was: MW > PS > T for TOC removals, PS > MW > T for color removals, and MW > PS > T for UV254 removals. The quality loss function values were used to compare the quality loss situation among different experimental conditions in the Taguchi OA design. The predicted removals of target parameters under the optimal conditions by Taguchi method and ANOVA were similar to the actual results from the confirmation experimental runs.