Reseach Of Pretreatment Of Coke Plant Wastewater By Chemical Oxidation

The quality of this coke plant wastewater was changing largely and the organism was high with poor biodegradability, so the water needed to be pretreated to degrade some organism and improve its biodegradability, and then it was more benefit to the follow biochemical treatment. In view of the coke plant wastewater treatment process status and existing problems, sodium hypochlorite, ozone, Fenton reagent chemical oxidations were used to pre-treat coke plant wastewater in this article and based on this study, the effect of several joint technologies was also researched. The text results showed that:In this condition:sodium hypochlorite dosing quantity was35mg/L,waste water initial pH value was6-9, and the reaction time was25minutes, CODCr and ammonia nitrogen removal efficiency were36.1%and99.2%respectively, and water biodegradability (BOD5/CODCr) raised to0.115by0.068of the raw water.The optimal parameters for O3oxidation to pre-treat coke plant wastewater: initial pH value was9, water temperature was30centigrade and reaction time was3minutes, in this condition, CODCr was no lower than the raw water instead of high and water biodegradability can be increased to0.289.The primary and secondary factors infecting Fenton reagent oxidation to degrade coke plant wastewater were:Fe2+dosing quantity>H2O2dosing quantity>reaction time>reaction initial pH. The optimal process conditions for Fenton reagent oxidation to pre-treat coke plant wastewater were:Fe2+and H2O2dosing quantity being1.0g/L and7.2g/L respectively, initial pH value being3, the reaction time being35minutes, reaction temperature being30centigrade, in this condition, CODCr and ammonia nitrogen removal efficiency were as high as40%and78.6%respectively, and water biodegradability can be more than0.462.Through the economic analysis, pretreatment of coke plant wastewater processing cost of each ton of water were:sodium hypochlorite oxidation was0.084yuan, ozone oxidation was0.60yuan,7.7yuan for the Fenton reagent oxidation.Using coagulation, iron filings and microwave combined with O3in treatment of coke plant wastewater, the results showed that:the best was microwave combining with O3.When the microwave current was320mA, the removal rate of CODcr and biodegradability were respectively30.2%and0.355.Using coagulation, fly ash and microwave combined with Fenton reagent in treatment of coke plant wastewater, the results showed that:the best was microwave combining with Fenton reagent. When the microwave current was320mA, the removal rates of CODcr and ammonia nitrogen were respectively42.9%and94.6%, and the biodegradability reached to0.497.Comprehensively comparison, ozone oxidation was both technically and economically feasible, and if combined with microwave technology, the effect was much better.