Treatment of Industrial Wastewater Derived Organic Pollutants Using Electrochemical Methods Through Optimization of Operation Parameters.

• Main Author: Sharma, Swati
• Format: Others
• Published: North Dakota State University 2019
• Subjects: chemical oxygen demand; electrochemical peroxidation; electrocoagulation; electrooxidation; industrial wastewater; organic carbon
• Online Access: https://hdl.handle.net/10365/29268

Industrial operations produce a notable amount of wastewaters with high concentration of chemical oxygen demand (COD), mostly consisting of organic carbon compounds. The treatment performance of electrochemical methods for organic removal and the effects of process parameters are the subject of this research. Three research tasks were performed. The first task was the removal of organic pollutants from three different industrial wastewaters using two different electrochemical methods; combined electrocoagulation + electrooxidation (EC+EO) and b) electrochemical peroxidation (ECP). Using only EC process was found to be significantly successful in removing suspended and colloidal pollutants and could remove more than 90% COD and 80% of TOC. The study showed that combined EC+EO process had better removal capability compared to ECP when operated under similar process conditions. The second task was to study the effect of the process parameters; pH, H2O2 dosage, current density, and operation time; and to optimize and estimate the best treatment conditions for the methods using Box-Behnken Design (BBD). For sugar beet wastewater, the results showed that EO could remove 75% of organics at optimum conditions of pH 5.3; current density of 48.5 mA/cm2; and operation time of 393 min. The canola oil refinery wastewater achieved more than 90% pollutant removal when the conditions were optimized at pH 5.8 – 6 with applied current density of 9.2 mA cm-2¬ run for nearly 300 min. The rate of degradation of the wastewater derived organic pollutants followed a first order kinetics for all the wastewaters investigated and the models were validated for goodness of fit with high R2. The final task was to compare treatment efficiency between the electrochemical processes. Based on the energy consumed and the performance efficiency to remove COD, sCOD, TOC and DOC in the three different wastewaters studied, EC+EO process was found suitable for the treatment of canola and sunflower oil wastewater. On the other hand, from the model prediction and the experiments conducted, EO resulted in better removal capability compared to ECP. Also, the consumption of energy by ECP was comparatively higher than EO process while taking longer time of operation for significant removal. === North Dakota Water Resources Research Institute; North Dakota Agricultural Experimental Station; Frank Bain Agricultural Scholarship