Research On Treating Coking Wastewater By High Voltage Pulse Discharge

Coking wastewater has large numbers of cyanide,hydroxybenzene,ammonia nitroge and organic compounds, it is dangerous for environment. This paper treat coking wastewater using discharge plasma generating by high voltage nanosecond pulse .In the treating process, many active plasma like ozone or hydronium were produce by actinic oxygenation and high-octane ion bombardment. If the condition is perfect , all the pollutants will be removed , and there is no second pollute.In this experiment , CN- were oxidated to be CNO- ,and then they were hydrolyzed to be NH3 and HCO-3,or they were oxidated to be N2 and CO2 directly. The COD of coking wastewater is high because of many kinds of aryl compounds , active plasma can break the chemical bond , then the aryl compounds were turned to be little molecules. The ammonia nitrogen were oxidated to be N2 and NO3-. We obtained some results as follow(pH=9.45):(1) The removal efficiency of CN- goes up gradually with airflow rate adding,SO2 concentration adding and reaction time prolonging. Airflow rate influence the removal efficiency of CN- more heavily than SO2 concentration.(2) The removal efficiency of ammonia nitrogen goes up with airflow rate adding , but SO2 concentration doesn't influences it much.(3) Airflow rate doesn't influence COD much, COD goes up in the early experiment ,and then goes down after 40 minutes.