2-丁烯醛生产废水的臭氧脱毒预处理

Crotonaldehyde manufacture wastewater (CMW) contains high-strength organic pollutants and is highly toxic to microorganisms, which makes it impossible to directly discharge into biological processing units. Therefore, ozone oxidation was employed to pretreat CMW to reduce its biological toxicity. The optimum reaction parameters of ozonation were obtained by monitoring the removal efficiencies of chemical oxygen demand (COD_Cr), total organic carbon (TOC), ultraviolet spectrum (UV₂₅₄) and the inhibition ratio of specific methanogenic activity (SMA). Moreover, the mechanism of detoxification by pre-ozonation was also discussed. The results showed that the optimal removal efficiencies of COD_Cr, TOC and UV_{254 nm} were 19.9%, 9.9% and 70.6%, respectively at a reaction time of 180 min, an initial pH of 3.0, a reaction temperature of 35 ℃ and an ozone concentration of 30.3 mg/L in gas phase and gas flow of 500 mL/min. The main organic pollutants, including crotonaldehyde, (E,E)-2,4-hexadienal, 3-(2-methyl-2-propylene)-5-pentanolactone, 5-formyl-6-methyl-4,5-dihydropyran and ethyl sorbate, were all removed by over 74.0%. The inhibition ratio of CMW to SMA was decreased from 82.0% to 47.2% after ozonation. The degradation process of COD_Cr, TOC and UV_{254 nm} by ozonation conforms to the first-order kinetic model and the R² values were 0.82, 0.97 and 0.94, respectively. This study indicated that the pre-ozonation could effectively degrade the main organic pollutants in the CMW and reduce its anaerobic biological toxicity to methanogenesis. The ozone oxidation process could be utilized as an efficient pretreatment method to CMW.