2-丁烯醛生产废水的臭氧脱毒预处理

Detoxification of Crotonaldehyde Manufacture Wastewater Pretreated by Ozone Oxidation Process

CMW(crotonaldehyde manufacturing wastewater,2-丁烯醛生产废水)污染物浓度高、毒性强、直接采用生物法处理难度大.为了降低CMW的生物处理毒性,采用臭氧氧化法对CMW进行脱毒预处理,并通过考察不同臭氧氧化条件对废水CODCr、TOC(总有机碳)、UV254 nm去除率及SMA(specific methanogenic activity,比产甲烷活性)抑制率的影响,获得了优化的臭氧氧化条件,进一步分析了废水脱毒机理.结果表明:①优化的臭氧氧化条件为接触反应时间180 min、初始pH 3. 0、反应温度35℃、气相臭氧浓度30. 3 mg/L,进气流量500 m L/min;并且在该条件下,CMW中CODCr、TOC和UV254 nm的去除率分别为19. 9%、9. 9%和70. 6%,主要特征有机污染物〔包括2-丁烯醛、(E,E)-2,4-己二烯醛、3-(2-甲基-2-丙烯)-5-戊内酯、1,5-二甲基-1-烯-4-羰基-环氧己烷、山梨酸乙酯等〕的去除率在74. 4%以上.②厌氧产甲烷毒性试验结果显示,CMW的SMA抑制率由臭氧氧化前的82. 0%降至臭氧氧化后的47. 2%.③反应动力学研究显示,CMW中CODCr、TOC及UV254 nm的去除过程均符合一级反应动力学方程,R2分别为0. 82、0. 97、0. 94.研究显示,臭氧氧化预处理可以较好地去除CMW中的特征有机污染物,降低废水的厌氧生物处理毒性,是一种可行的脱毒预处理方法.

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(CODCr),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 CODCr,TOC and UV254 nmwere 19.9%,9.9%and 70.6%,respectively at a reaction time of 180 min,an initial p H 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 m L/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 CODCr,TOC and UV254 nmby ozonation conforms to the firstorder 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.