Statistical Optimization of Vegetable Washwater Treatment Using Electrocoagulation

This study investigates the application of electrocoagulation (EC) for treating vegetable washwater (VWW). Preliminary EC experiments were carried out to define the operational parameter ranges supporting a subsequent statistical optimization of the process. The optimization aimed to identify the most efficient operating conditions for pollutant removal while minimizing energy consumption. VWWs were sampled from four root vegetable washings (potatoes, leeks, and red beets). Various EC tests carried out using a 500-mL reactor and a response surface methodology of experiments enabled us to obtain optimum operating conditions for the treatment of VWW. Thus, optimal conditions of a current intensity of 0.32 A for 8.8 min with aluminum electrodes gave total suspended solid (TSS) and turbidity reduction rates of 99% and 98%, respectively, along with a total phosphorus reduction rate of 93% for Farm 1. EC VWW treatment generally met the regulatory discharge limit of 50-mg/L TSS. Only TSS of Farm 4 remained well above the limit. EC also reduced neonicotinoid insecticides present in VWW by 38%, and the true color of beet roots decreased from 283 to 60 UCV. The energy costs associated with VWW clarification treatment ranged between CAD$0.06/m³ and CAD$0.09/m³.