(376c) Degradation of 1,4-Dioxane in Wastewater with Electrochemical Advanced Oxidation Processes (EAOPs)

Woisetschläger, D., Graz University of Technology
Zelenka, J., VTU Technology
Humpl, B., VTU Engineering
Siebenhofer, M., Graz University of Technology

1,4-dioxane is frequently used in industry as a solvent for organic and inorganic compounds and can be found in effluents of pharmaceutical processes. It is specified as a toxic pollutant for the aquatic ecosystem and is a suspected carcinogen. Hence it is classified as a hazardous pollutant. Emission of 1,4-dioxane into wastewater must be prevented. Degradation of 1,4-dioxane with wastewater treatment processes based on mass transfer unit operations is not very efficient due to its high aqueous solubility and resistance to biodegradation. As a consequence alternative methods, such as advanced oxidation processes are required.

Electrochemical advanced oxidiation processes (EAOPs) provide effective water purification and can eliminate persistent pollutants. Although less economic than conventional treatment techniques for complete pollutant mineralization, EAOPs can be used cost effectively to partially oxidize persistent pollutants into less toxic and more biodegradable intermediates.

Aim of this project was technical evaluation of an effective and efficient 1,4-dioxane degradation process. Electrocatalysis and the process parameters mass transport, current density were investigated and modeled. Investigations were performed in a modified flow-through reactor with anodes of distinct O2 evolution overpotential (BDD anodes and Pt-coated titan anodes) and high electrochemical stability. Considering industrial scale application target was the optimization of the decomposition rate and energy consumption in terms of the area-time-yield. For a scale-up the maximum compound and electrode specific current density for defined flow conditions was determined. With an optimization of the area-time yield an industrial use of the electrochemical oxidation process for treatment of 1,4-dioxane contaminated wastewater is possible and economically feasible.