Nano-TiO2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO2 dosage and initial p H of the wastewater ...Nano-TiO2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO2 dosage and initial p H of the wastewater on the removal rate of COD were tested. The GC/MS and EEM techniques were used to qualitatively analyze organic compounds in the wastewater before and after treatment. The result showed that after the biologically treated chemical comprehensive wastewater was treated by nano-TiO2 photocatalytic oxidation under the conditions of reaction time 3 h,nano-TiO2 dosage 8 g/L,and pH 8. 0,the effluent COD was 61. 9 mg/L and its removal rate was 63. 8%. Additionally,the species of organic pollutants reduced from 12 to 6. Meanwhile,the content of humic-like and fulvic-like substances dropped dramatically.展开更多
Conventional biological treatment process is not very efficient for the treatment of petroleum refinery wastewater （PRW） that contains high-concentration of organic contaminants. Prior to biological treatment, an ad...Conventional biological treatment process is not very efficient for the treatment of petroleum refinery wastewater （PRW） that contains high-concentration of organic contaminants. Prior to biological treatment, an additional pretreatment process for PRW is required for the effluent to meet the discharge standards. While re-circulated bio-filter （RBF） has been applied as a pretreatment process in several PRW treatment plants, its effects have not been comprehen- sively evaluated. In this study, the parameters of operation, the changes in pollution indexes and contaminant composition in an engineered RBF have been investigated. We found that mainly highly active de-carbonization bacteria were present in the RBF, while no nitrification bacteria were found in the RBF. This indicated the absence of nitrification in this process. The biodegradable organic contaminants were susceptible to degradation by RBF, which decreased the Biological Oxygen Demand （BODs） by 83.64% and the Chemical Oxygen Demand （CODcr） by 54.63%. Consequently, the alkalinity and pH value of RBF effluent significantly increased, which was unfavorable for the control of operating parameters in subsequent biological treatment. Along with the decrease of CODcr, the RBF effluent exhibited a reduction in biodegradability. 834 kinds of recalcitrant polar organic contaminants remained in the effluent; most of the contaminant molecules having complex structures of aromatic, polycyclic and heterocyclic rings. The results of this study showed that RBF could efficiently treat PRW for biodegradable organic contaminants removal; however, it is difficult to treat bio-refractory organic contaminants, which was unfavorable for the subsequent biological treatment process operation. An improved process might provide overall guarantees for the PRW treatment.展开更多
文摘Nano-TiO2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO2 dosage and initial p H of the wastewater on the removal rate of COD were tested. The GC/MS and EEM techniques were used to qualitatively analyze organic compounds in the wastewater before and after treatment. The result showed that after the biologically treated chemical comprehensive wastewater was treated by nano-TiO2 photocatalytic oxidation under the conditions of reaction time 3 h,nano-TiO2 dosage 8 g/L,and pH 8. 0,the effluent COD was 61. 9 mg/L and its removal rate was 63. 8%. Additionally,the species of organic pollutants reduced from 12 to 6. Meanwhile,the content of humic-like and fulvic-like substances dropped dramatically.
基金supported by the National Natural Science Foundation of China (No. U1462201)China National Offshore Oil Corporation (CNOOC-KJ125 ZDXM 15 LH007 LH12) project
文摘Conventional biological treatment process is not very efficient for the treatment of petroleum refinery wastewater （PRW） that contains high-concentration of organic contaminants. Prior to biological treatment, an additional pretreatment process for PRW is required for the effluent to meet the discharge standards. While re-circulated bio-filter （RBF） has been applied as a pretreatment process in several PRW treatment plants, its effects have not been comprehen- sively evaluated. In this study, the parameters of operation, the changes in pollution indexes and contaminant composition in an engineered RBF have been investigated. We found that mainly highly active de-carbonization bacteria were present in the RBF, while no nitrification bacteria were found in the RBF. This indicated the absence of nitrification in this process. The biodegradable organic contaminants were susceptible to degradation by RBF, which decreased the Biological Oxygen Demand （BODs） by 83.64% and the Chemical Oxygen Demand （CODcr） by 54.63%. Consequently, the alkalinity and pH value of RBF effluent significantly increased, which was unfavorable for the control of operating parameters in subsequent biological treatment. Along with the decrease of CODcr, the RBF effluent exhibited a reduction in biodegradability. 834 kinds of recalcitrant polar organic contaminants remained in the effluent; most of the contaminant molecules having complex structures of aromatic, polycyclic and heterocyclic rings. The results of this study showed that RBF could efficiently treat PRW for biodegradable organic contaminants removal; however, it is difficult to treat bio-refractory organic contaminants, which was unfavorable for the subsequent biological treatment process operation. An improved process might provide overall guarantees for the PRW treatment.
