Strengthen Phosphorus BAF-ozone Combined Process Water Depth Study Of Petrochemical Secondary Treatment

With increasing environmental protection efforts, Operation and technology research of petrochemical industry wastewater treatment process is particularly urgent. Petrochemical wastewater treatment plant secondary effluent was large amount of the water, the organic matter was difficult to degradate and had some toxicity. If realized its recycling, not only can reduce the petrochemical wastewater to secondary pollution of natural water bodies, but also they can help relieve the water resources in China shortage of pressure. The upcoming implementation of the "petrochemical industry emission standards" from March 1, 2015, the COD emission limits is scheduled for 60 mg/L or less. Petrochemical sewage treatment plant secondary effluent COD concentration is generally higher than ordinary secondary effluent from sewage treatment plants, BOD5 is usually 5.0 mg/L or less.Due to wastewater treatment plant of large-scale industrial park usually focus on organic matter(COD) removal of adding nitrogen and phosphorus and other nutrients to adjust water quality, but the actual process has not nutrient removal unit. Secondary effluent biochemical cause excessive nutrients, especially phosphorus content exceeded the phenomenon is more common.This topic used to strengthen phosphorus BAF- ozone combination treatment of petrochemical wastewater effluent depth, examining the impact of reactor operating parameters for wastewater organics, nutrients removal effect.Studied biofilm activity and biological advantages of flora distribution of BAF. FeSO4 continuous dosing study the impact on the biological activity in the BAF and surface properties; and the relative molecular mass of petrochemical secondary effluent and this effluent water, three-dimensional fluorescence spectrum, semi-volatile organic compounds and other organic matter characteristics were studied.The effect of combination treatment operating conditions were investigated.The result shows that under the conditions of HRT =1h, gas-water ratio = 3: 1, dosage of ozone 30 mg·L-1, contact time of 30 min, the average removal rate of COD,TN,TP were 31.38%,9.12% and 67.61%.The effluent average COD, NH4 +-N, TN,TP and color were 45.54 mg·L-1, 1.81 mg·L-1, 16.98 mg·L-1, 0.44 mg·L-1and 20. The indexes of the effluent are up to the standard of pollutant discharge for petrochemical industry. Through the inlet and outlet water quality and biofilm activity of factor analysis, BAF segment microbial populations and their advantages of organic matter, nutrient removal along the flow direction of the gradient changes. Microbes are more concentrated in the lower part of the reactor, and higher microbial activity. The lower part of biofilm structure more closely, on the growth of a large number of bacteria, bacteria and filamentous bacteria. And continuous dosing FeSO4 for BAF effluent and Microbial activity was not inhibited. Because iron phosphate precipitate formed on the surface and makes the filter compact and less porosity biofilm. Ozonation contact early stage in order to change the structure of organic compounds in waste water to the open-loop, scission of small organic molecules, then the mineralization to CO2 and H2 O. FeSO4 dosing makes BAF effluent with a certain amount of Fe, ozonation improve efficiency. The proportion of organic raw water by the combined process of relative molecular mass of less than 1 × 103 increase. Ozone oxidation can make macromolecules wastewater broken into small molecules, and small molecules have be a certain removed. Ozone oxidation of secondary metabolites and microbial removal of humic acids have better results. GC-MS results showed that Biochemical petrochemical wastewater secondary effluent was detected about nine kinds of organic compounds in the main. After ozone oxidation of unsaturated bond-containing organic compounds removed the obvious.Considering the feasibility of the process, pharmaceutical costs and infrastructure costs, the combination of strengthen phosphorus BAF and ozone handle large petrochemical Secondary Effluent have good prospects for development.