Research On The Treatment For The Concentrated Water Of Membrane System In Sewage Reuse Of Oil Refining And Chemical Enterprises

With our nation advocating the policies of energy saving,water conservation and emission reduction,more and more oil refining and chemical enterprises make sewage "zero emissions" as the ultimate goal of wastewater treatment, wastewater reuse become one of the main measures for "zero emissions".The membrane separating technology is an effective method to achieve the wastewater reuse of oil refining and chemical enterprises. With the membrane separating technology producing the recycle water purification, some concentrated water are also produced and need further treatment in order to achieve discharge standards. In this paper, the RO concentrated water collected from the wastewater reuse devices of a petrochemical company in Qingdao are used as the research object,and the treatment effect of following methods to treat concentrated water are separately studied.RO concentrated drainage of petrochemical sewage reuse was treated by Fenton, based on the single factor experiments, Response surface analysis results showed that the model regression results between H2O₂ dosage, FeSO4·7H2O dosage, initial pH and the COD removal rate were obvious. The optimum reaction conditions were that H2O₂ dosage, FeSO4·7H2O dosage, initial pH, reaction time and adding frequency were 0.66mL/L, 2.45g/L, 3.01,1.5h and three times respectively, under these conditions, COD removal rate reached 59.96% and the chromaticity removal rate reached 73.41%. The UV / Fenton treatment effect is significantly higher than the Fenton reagent.RO concentrated drainage of petrochemical sewage reuse was treated by suspended TiO₂ photo-catalysis, based on the single factor experiments, Response surface analysis results showed that the model regression results between initial pH, H2O₂ dosage, TiO₂ dosage, aeration quantity and the COD removal rate were obvious. The optimum reaction conditions were that mercury-lamp, pH value of, TiO₂ dosage of, H2O₂ dosage, aeration dosage, reaction time were 500 W, 3.92, 0.71g/L, 0.95ml/L, 0.68L/min,2h respectively, under these conditions, COD removal rate reached 94.79% and the chromaticity removal rate reached 98.34%. The treated wastewater can meet the Class I of integrated wastewater discharge standard in shandong peninsula basin.The TiO₂ photocatalysts immobilized on 13 X molecular sieve were prepared by powder sintering method.2g 13 X molecular sieves were added to the suspensions containing 0.4g TiO₂,and calcined 2.5h in the temperature of 500 to make the TiO₂/ molecular sieves. Adding the TiO₂/ molecular sieves to 250 ml concentrated water,the COD removal rate and the chromaticity removal rate of concentrated water reached 89.36%,98.69% respectively after treatment.But the catalytic activity falling fast, not suitable for resue.The TiO₂ photocatalysts immobilized on activated carbon of 60-80 mesh were prepared by sol-gel method under the condition of calcined 2h in the temperature of 500. Adding the TiO₂/ AC of 1.4g/L to 250 ml concentrated water, the COD removal rate and the chromaticity removal rate of concentrated water reached 89.36%,98.69% respectively after treatment.The TiO₂/AC still showed high catalytic activity after five time cyclic utilization.