Treatment of coke oven wastewater using ozone with hydrogen peroxide and activated carbon

Demand of metallurgical coke results in generation of large amount of coke oven wastewater. Treatment of this wastewater was done with ozone which was used in combination with activated carbon (AC) and H2O2 to increase the degradation of chemical oxygen demand (COD). To optimize the parameters which influence the COD degradation of coke oven wastewater Response surface methodology (RSM) was used. The optimized condition for treatment with ozone and activated carbon is pH 5, 13.5 min of reaction time and 2 g/L activated carbon while for the treatment using ozone along with H2O2 was pH 9.5, 3.5 g/L H2O2 concentration and 27.5 min of reaction time. The maximum degradation of COD achieved in the O-3/AC was 76.79% while in the O-3/H2O2 process the COD removal was 75.8%. Study of both the treatment processes suggests that both the processes follow pseudo second order kinetics with constants 16.10 x 10(-5) L/min.mg for the O-3/AC process and 7.04 x 10(-5) L/min.mg for the O-3/H2O2 process. The O-3/AC process is more acceptable in terms of fast rate of COD degradation, economy and efficiency of the process as it requires less time and hence proposed treatment scheme which could degrade COD of large volume of wastewater.