Continuous flow electrocoagulation for MSG wastewater treatment using polymer coagulants via mixture-process design and response-surface methods

This study investigates the feasibility of applying a continuous wastewater treatment, which is accomplished using a plate-type electrocoagulator in a zigzag flow pattern in series of bipolar plates. Compared to conventional coagulation-flocculation techniques, the continuous flow electrocoagulation was found to be advantageous for the facile removal of COD and colored pollutants from wastewater. On the other hand, there are more operating cost accompanying the excess energy consumption and the short lifetime of electrodes due to high acidity and salt concentration in the monosodium glutamate (MSG) wastewater used. Hence, electrocoagulation experiments with a co-current feeding of polymer coagulants were conducted to improve the treatment for MSG wastewater. We applied statistical design of experiments in an effective approach for the screening and simulation of the influence of operational variables via mixture-process experiments and response-surface methods. The results of multiple regression analysis suggest crucial effects of applied cell voltage, feed flow rate, and ternary polymer coagulants on the response performance. This approach also led to the optimization of mixture constituents for ternary polymer coagulants under an electric field. Here the maximum removals of color and COD for MSG wastewater treatments were obtained at continuous removal rates of 86% and 68%, appreciably better than those of individual polymer components alone or without polymer used. This study therefore indicates the promising potential of the continuous flow electrocoagulation for wastewater treatments.

► Continuous flow electrocoagulator shows a zigzag up-flowing wastewater mixed with metallic species and polymer coagulants.
► Electrocoagulation for MSG wastewater treatment was modeled and analyzed with mixture-process design and response surface method.
► Increasing cell voltage and polymer dosage will increase removal rates of color and COD if flow rate and organic loading rate are constant.
► Increasing electric charge loading rate will decrease electrode lifetime.
► Maximal rate of decolorization and COD removal depends on optimal values of mixed-polymer dosage and operating variables.