Abstract:In order to solve the problem that petrochemical wastewater is difficult to meet the new local standards, the DNF-O3-BAC combined process was used to perform advanced treatment of it. Various nitrogen forms, COD, UV254 and molecular weight distribution in effluent were tested by ultraviolet spectroscopy, K2Cr2O7 oxidation method, etc., respectively. The effects of different carbon sources and C/N on denitrification performance of DNF unit were studied, and the advanced treatment mechanism of petrochemical wastewater by DNF-O3-BAC process was also explored. The results showed that the removal rate of ${\rm{NO}}_3^{-} $-N could reach 96.7% and almost no ${\rm{NO}}_2^{-} $-N accumulated at C/N of 4, HRT of 2h and the most suitable carbon source of sodium acetate. At the best O3 dosage of 20 mg·L?1, the removal rate of COD was about 45%, the B/C ratio was stable above 0.2, and the removal rate of UV254 reached 14%. At O3 dosage of 20 mg·L?1, the optimal contact time was 40 min, and COD removal rate reached 42%, the B/C ratio was stable at 0.28, and UV254 removal rate reached about 34%. Compared with influent water, the proportion of organic matter with molecular weight ≤1 kDa increased from 69% to 86%. Under the optimal conditions of each unit, the COD in effluent of DNF-O3-BAC process reached 25 mg·L?1, UV254 was stable at 0.11, and TN reached 2 mg·L?1. DNF-O3-BAC combined process could realize the degradation of organics and TN in petrochemical wastewater, and the effluent water quality met the local standards. Key words:advanced treatment/ ozone oxidation/ petrochemical wastewater/ combination process/ denitrification.
图1实验装置流程图 Figure1.Schematic diagram of experimental devices
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School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China Received Date: 2018-11-10 Accepted Date: 2019-05-26 Available Online: 2020-11-11 Keywords:advanced treatment/ ozone oxidation/ petrochemical wastewater/ combination process/ denitrification Abstract:In order to solve the problem that petrochemical wastewater is difficult to meet the new local standards, the DNF-O3-BAC combined process was used to perform advanced treatment of it. Various nitrogen forms, COD, UV254 and molecular weight distribution in effluent were tested by ultraviolet spectroscopy, K2Cr2O7 oxidation method, etc., respectively. The effects of different carbon sources and C/N on denitrification performance of DNF unit were studied, and the advanced treatment mechanism of petrochemical wastewater by DNF-O3-BAC process was also explored. The results showed that the removal rate of ${\rm{NO}}_3^{-} $-N could reach 96.7% and almost no ${\rm{NO}}_2^{-} $-N accumulated at C/N of 4, HRT of 2h and the most suitable carbon source of sodium acetate. At the best O3 dosage of 20 mg·L?1, the removal rate of COD was about 45%, the B/C ratio was stable above 0.2, and the removal rate of UV254 reached 14%. At O3 dosage of 20 mg·L?1, the optimal contact time was 40 min, and COD removal rate reached 42%, the B/C ratio was stable at 0.28, and UV254 removal rate reached about 34%. Compared with influent water, the proportion of organic matter with molecular weight ≤1 kDa increased from 69% to 86%. Under the optimal conditions of each unit, the COD in effluent of DNF-O3-BAC process reached 25 mg·L?1, UV254 was stable at 0.11, and TN reached 2 mg·L?1. DNF-O3-BAC combined process could realize the degradation of organics and TN in petrochemical wastewater, and the effluent water quality met the local standards.
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