| The pesticide industrial wastewater was a kind of hazardous wastewater for environment and society, which generally have characteristic with high organic contents, deep chroma, obviously off-odour, high COD value, worse biodegradability. The oxadiazon industrial wastewater is the typical one of the difficult treated pesticide wastewater. The prominent and austere environmental issue is to deal with the pesticide wastewater effectively. Innovative treatment technology of the pesticide wastewater needs to be researched.In this paper, the treatment technology and methods at home and abroad of pesticide industrial wastewater were investigated at length. Dielectric barrier discharge (DBD) non-thermal plasma technology is worthy for treating pesticide in industrial wastewater in pre-research. Therefore, DBD non-thermal plasma technology was introduced into the oxadiazon industrial wastewater treatment. As the four aspets of the research were carried out:①The treatment device of DBD plasma was designed, and its structure was optimized by studing on the effect of the air gap distance, gas inlet position and input power on the discharge.②The main pollutants as the imitated wastewater of the oxadiazon wastewater were treatment by DBD plasma. The effect of the discharge condition(including input voltage and gas flow) and the water quality (including initial concentration, initial pH and water flow) on COD, TOC, chroma, ion concentration and conductive were studied on in this paper. In addition, the pathway and mechanism of the degradation were exploded by detecting the intermediate product.③The oxadiazon industrial wastewater were treatment by DBD plasma. The effect of the discharge condition and the water quality on COD, TOC, chroma, ion concentration and conductive were studied on. The better treatment condition and effect were confirmed finally.④The feasibility of the industrial amplification was verified by optimizing and magnified device and analyzing the energy efficiency.The following results were obtained by the above research.① The better condition was confirmed by multiple contrast experimental verification, such as, the discharge voltage was about 6 kV, the discharge current was about 12 mA, the solution flow rate was about 15～20 L/h, the Ar and O2 inlet flow rate were both about 40 mL/min; COD degradation rate was highest at the same treatment time when initial pH was about 8-10, and it was insusceptible with initial concentration of the samples.② The removal rate of the oxadiazon simulating aqueous solution which initial concentration was about 80 mg/L reached at about 99% during 30 min. The COD degradation rate was about 68.5% during 30 min and was about 96.1% after 300 min treatment. The removal rate of the 2,4-dichloro-5-nitro phenol simulating aqueous solution which initial concentration was about 220 mg/L reached at about 100% during 15 min. The COD degradation rate was about 88.9% after 180 min treatment③ The degradation products of the main pollutant was analyzed by multiple means. The result showed that the main pathway of degradation included being attacked, ring opening, and mineralization. Micromolecular organic acids were the main products of halfway mineralizing. The N and Cl which was the element of the pollutant were converted inorganic ions into aqueous solution finally.④ The oxadiazon industrial wastewater which was with brown-red color and pungent smell was converted to colorless and tasteless by DBD plasma treatment. The COD was reduced from 28250 mg·L-1 to2883 mg·L-1, the BODs/COD was increased from 0.28 to 0.68, the biodegradability was improved obviously. The COD of the wastewater which was treated by plasma was reduced from 2883 mg·L-1 to 853 mg-L-1 by biological treatment 3 days sequentially.⑤ The energy efficiency G (mg/J) and electrical energy efficiency E (mg/J) was in used to compare the energy dissipation of two reactors, the one was magnified device with liner DBD structure, the other one was coaxial DBD structure. The result showed that handling capacity of the former was 10 times of the latter, the real power was 6 times of the latter, the electrical energy efficiency of the former was improved about 60% than the latter, and the energy efficiency of the former was improved about 55% than the latter.The oxadiazon industrial wastewater was treated by DBD non-thermal plasma for the first time in my research. The degradation machnism of plasma treatment was explored by studying on the degradation of oxadiazon simulating aqueous solution. The liner DBD nonthermal plasma device was the effective amplifying device of the coaxial DBD plasma, and it is most prospective applied in oxadiazon industrial wastewater or the analogical industrial wastewater. |
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