Removal of microplastics in food packaging industry wastewaters with electrocoagulation process: Optimization by Box-Behnken design

Abstract

Currently, the vast majority of studies on microplastics (MPs) focus on determining the quantity and presence of these particles in various receiving environments and their treatment in domestic wastewater treatment plants. However, little research has been conducted on the treatment of microplastics in industrial effluent. Therefore, in this study, effluent samples from the cooling water tank of a local food packaging manufacturing company were analyzed to determine the presence and quantity of MPs for the first time. MPs removal from industrial wastewater using the electrocoagulation (EC) method was optimized using the Box Behnken Design (BBD). A second-order model was developed to estimate the microplastic removal efficiency, and the R2, adjusted R2, and predicted R2 of the model were 0.9994, 0.9985, and 0.9962, respectively. The optimal reaction parameters resulting in the maximum removal rate of microplastics (99 %) were determined to be pH 6.74, current density of 3.16 mA cm−2, and duration of 13.58 min. The cost of microplastic treatment per m3 of wastewater in the EC system, operated under optimal conditions, was calculated as 0.125 $. In this study, it was concluded that the EC process is a highly efficient technique for the removal of MPs from industrial wastewater at a low cost. Determining the most favorable conditions with BBD for the EC process at the feasibility stage of treatment plants will provide economic benefits and increase treatment efficiency during the installation of large-scale plants.