炼化企业停工大检修污水水质特性综合表征

Comprehensive analysis and characterization of overhaul wastewater from petrochemical refineries

炼化企业停工大检修期间无组织排放大量高浓度污水,对综合污水处理厂的正常运行构成严重冲击。将宏观污染指标与微观污染组成相结合,从污染负荷、体系稳定性、污染组成及生物毒性4方面,对清洗污水和清洗-钝化混合污水两类典型大检修污水进行水质特性综合分析。清洗污水和清洗-钝化混合污水均表现出极高的有机污染负荷、悬浮态和胶体态污染物、体系稳定性以及较强的急性生物毒性。清洗污水和清洗-钝化混合污水的有机污染组成复杂,两者的极性污染物组成均以OxS1类为主,前者以O3S1类污染物相对丰度最高,推测源自磺酸盐类表面活性物质;后者以O4S1类污染物相对丰度最高,推测源自烷基硫酸盐类或硫酸酯盐类表面活性物质。两者的弱极性污染物组成差异较大,清洗污水以醇醚类、醚类和石油烃类为主,而清洗-钝化混合污水则主要是小分子杂环类、芳香烃类和酚类。对两类典型大检修污水水质特性的分析研究可指导大检修污水预处理工艺开发,为炼化企业大检修期间综合污水处理厂的稳定运行提供支持。

During the overhaul of petrochemical refineries,a large amount of wastewater will be discharged unorganized,which has a serious impact on the operation of wastewater treatment system.In this study,macroscopic pollutant index analysis was combined with microscopic pollutant composition analysis,and the water quality of cleaning wastewater and cleaning-passivation wastewater were characterized from four aspects:pollutant load,system stability,pollutant composition,and biological toxicity.Both cleaning wastewater and cleaning-passivation wastewater exhibited high organic pollutant loads,high concentrations of suspended and colloidal pollutants,high system stability,and strong acute biological toxicity.The composition of polar pollutants of cleaning wastewater and cleaning-passivation wastewater was dominated by OxS1.Cleaning wastewater had the highest relative abundance of O3S1,which was speculated to be derived from alkyl benzene sulfonates.The relative abundance of O4S1 was the highest in cleaning-passivation wastewater,which was presumed to come from alkyl sulfates or sulfate surfactants.There was a significant difference in the composition of weakly polar pollutants between the cleaning wastewater and cleaning-passivation wastewater.Cleaning wastewater was mainly consisted of alcohol ethers,ethers,and petroleum hydrocarbons.Cleaning-passivation wastewater was mainly consisted of small molecule heterocycles,aromatic hydrocarbons,and phenols.The results could guide the development of pretreatment processes for overhaul wastewater,and provide support for the stable operation of comprehensive wastewater plant during overhaul of petrochemical refineries.