焦化废水处理工程中,经过生物和混凝处理后,排放到环境中的尾水COD处于(85±20)mg·L-1范围内,这部分COD主要由一些难生物降解的物质构成,对水体环境造成污染,也给水回用带来了技术上的难度.为实现尾水中残留有机物的进一步削减,降低其在环境当中的危害,采用臭氧流化床反应器对焦化废水尾水进行深度处理并通过三维荧光光谱仪以及气相色谱/质谱(GC/MS)分析其水质组成的变化.结果表明:尾水在反应过程中,投加的臭氧量与降解的COD之间的比值(O3(kg)/COD(kg))随反应时间的延长不断增大;当pH=10时,COD、UV254和色度的去除率分别为51.5%,87.3%和85.0%,去除效果优于pH=7和pH=5条件下的反应;臭氧氧化能够有效分解尾水中类色氨酸、类溶解性微生物副产物、类腐植酸和类酪氨酸物质;经臭氧氧化后,焦化废水尾水中一些难生物降解的有机物得到了部分或完全去除,转化为一些新的有机物,如烷烃、苯甲醇、己酸等物质.研究结果证明,影响尾水的臭氧氧化效率涉及反应器结构、废水溶液性质和反应条件.
After bio-treatment and coagulation of coking wastewater, the effluent still contains some non-biodegradable organics, and the COD concentration is about(85±20) mg·L-1, which would contaminate the water environment and cause difficulties in water reusing. To realize the further reduction of organic and the harm to environment, advanced treatment of bio-treated coking effluent was carried out by using ozone-fluidized bed and the composition was analyzed with three-dimensional fluorescence excitation-emission matrix and GC / MS. The results show that, within two hours reaction, the ratio of ozone dosage and COD degradation increased with time; under pH 10, the removal rate of COD, UV254 and color intensity were 51.5%、87.3% and 85.0% respectively, and the removal efficiency is higher than the reaction with that under pH 7 or 5. The results of three-dimensional fluorescence spectra shows that, ozonation can effectively decompose tryptophan-like, soluble microbial products-like, humic acid-like and tyrosine-like compounds in the bio-treated coking effluent. Results of GC / MS analysis also shows that some nonbiodegradable organics in wastewater have been partly or completely removed after ozonation, and alkane, benzyl alcohol, hexanoic acid were detected as by-products. The results showed that the reactor structure, coking wastewater properties and reaction conditions can significantly influence the ozonation efficiency for the advanced treatment of biological effluent.