Treatment of agrochemical wastewater by thermally activated persulfate oxidation method: Evaluation of energy and reagent consumption

Abstract

Agrochemical wastewater is a potential danger to public health, the environment, and other livings, as it contains hazardous compounds that can harm plants and animals and cause many diseases in humans. In this work, the thermally activated persulfate (TAP) oxidation method, which is an effective and practical approach for degradation of agrochemical wastewater, was carried out. Optimization and modeling of total organic carbon (TOC) and decolorization of the agrochemical wastewater were studied using a central composite design. Persulfate was thermally activated and the effect of the temperature, treatment time, and persulfate concentration on the TAP method was detailed. Temperature and persulfate concentration were the most effective process parameters for TOC removal. Results, model coefficients, and analysis of variance (ANOVA) showed that the resulting model was precise and acceptable for predicting TOC and color removals. The feasibility of energy and reagent consumption was proposed. Under conditions where TOC and color removal rates were reached 70.2% and 100%, the electrical energy and persulfate consumption were 529.5 kWhm−3 and 21.6 kgm−3, respectively. Chemical composition analysis of wastewater and treated samples showed that the TAP method was able to degrade almost all compounds found in this study, including those resistant to oxidation. Ion chromatography analysis showed that the ion concentration of the wastewater samples changes with the applied temperature and the oxidant concentration.