Study On Petrochemical Secondary Effluent Using Ozone-biological Aerated Filter

The wastewater with high energy consumption and high pollution generated by thepetrochemical industry has high concentration of organic pollutants,large amount ofqater, treating process is difficult and complex pollutants.In China, most of the largechemical industrial park wastewater through sewage treatment plants, effluent generallysatisfied discharge standards, But with China’s industrial wastewater emission targetsincreased every year, and faces growing water shortages and other serious problems, thedepth of petrochemical wastewater treatment has become an urgent problem.In this research, choseing ozone-BAF combined process of Petrochemicalsecondary effluent in-depth treatment.,systematic analysis of wastewater treatment planteffluent, ozone oxidation unit and BAF unit, various factors affecting the treatment ofpollutants run separately, In-depth study of the removal of wasterwater pollutants byozone-aBAFcombination technology and BAF-Ozone combined process,as well as acomprehensive analysis and a comparison on the various factors that influence thetreatment effect of wasterwater pollutants.The COD of petrochemical secondary effluent was between65~120mg/L, theconcentration of SS was between4.0~8.1mg/L and the concentration of NH4+-N wasbetween0.85~2.15mg/L, the TN of secondary effluent were fluctuations, some timescan not meet emission standards; wastewater contains many organic materials having anunsaturated bond, poor biodegradability, relative molecular mass of less than1Korganics more than50%of the total organic matter in water, relative molecular massof greater than1000K more than20%of the total organic matter, the organic matter theprotein contains a large amount of aromatic.The removal of waste-water colour and turbidity bu ozone is high.The ozoneoxidationof the secondary effluent showed that when the ozone dose of10mg/L and thecontact time of4min, the removals of COD, UV254were10.8%and11.6%. At the sametime, the ozonation changed the percentage of organic matters with relative molecularmass less than1K decreased18%.The biodegradability of secondary effluent by ozoneoxidation improve significantly. The removal of organic matters by ozone, in thealkaline conditions clearly stronger than acidic and neutral conditions.The aeration rate filter of the secondary effluent showed that the removalsefficiency of COD, UV254and NH4+-N were10.4%,7.64%,26%, respectively,when the gas-water ratio of4:1, the residence time of3h, BAF biodegradable function occursmainly in the lower packing (front from the water inlet30cm).The results of O3-BAF combined process showed that the O3-BAF process is betterthan BAF-O3in treating the petrochemical secondary effluent, The average COD ofinfluent was86.5mg/L, the average COD of effluent was49.4mg/L,the average UV254of influent was0.725, the average UV254of effluent was0.51,when the ozone dosage of10mg/L, ozone contact time of4min, BAF into the water to2L/h, hydraulic retentiontime was3h, gas-water ratio of4:1, By the GC-MS analysis, detected toxic andhazardous substances of wastewater has a significant reduction, Significantly improvedthe water quality of petrochemical wastewater.