Electrochemical Catalytic Oxidation Treatment of Coking Wastewater RO Brine

Abstract

Coking wastewater RO brine is considered to be refractory, toxic, mutagenic and carcinogenic. Electrochemical oxidation has attracted wide attention in wastewater treatment because of its strong oxidation performance and ease of control. In this paper, the electrochemical degradation of NH3-N and COD were investigated at different anodes materials and current densities .The electrochemical oxidation using Ti/RuO2IrO2anode was effective and promising for advanced treatment of coking wastewater RO brine. COD and NH3-N concentration degraded 86% and 100% in 80min at the current density of 5 mA cm-2. Current density is the most important factor of organic degradation and energy consumption. When the current density was 10mA cm-2, the COD removal ratio quickly increased to 52.94% in 20min reaction time, but under high current density, the life of the electrode will be reduced. When the current density is too low, the electrolytic reaction time to reach standard needs to be 2h or more, which will perpetuate the equipment bulky, increase the cost of the equipment. The optimal current density is 5.0 ~ 7.5 mA cm-2. Unit per COD energy consumption is 114.4 kWh kgCOD-1, and unit per cubic meter wastewater energy consumption is 5.9 kWh m-3at the current density of 5 mA cm-2.