Abstract: Water samples were collected from the key steps of two sewage treatment processes in a large petrochemical enterprise in Northwest China. The removal laws of volatile organic compounds in the whole wastewater treatment process were analyzed by ultraviolet-visible spectroscopy and purge-trap-GC-MS. 76 kinds of organic compounds were identified in total, while the chemical wastewaters (43) were more complex than the oil refinery wastewaters(32). The oil refining wastewater contains more sulfur compounds (sulfides and thiophene), which is the main source of fetor. Chemical sewage contains more nitrogenous compounds (nitro compounds, nitriles and cyanides), which are the main contributors to ammonia and total nitrogen. There are ten kinds of aromatic compounds, which contribute much to VOCs. The hydrolysis of chemical wastewater can produce some alcohols and ketones, which can improve the subsequent biodegradability. The biochemical treatment can remove the majority of alkanes, alkenes, alkynes and some alcohols, ketones, while aromatic hydrocarbons,polycyclic aromatic hydrocarbons and chlorinated hydrocarbon have lower biological degradability. As a result, these compounds still exist after biochemical process, which is an important reason for COD residue, and they are characteristic pollutants in refinery wastewater. The fine analysis in molecular level can provide a scientific basis for sewage treatment process evaluation, and thus help the process development and improvement.

Key words: chemical analysis, chromatography, drainage, volatile organic compounds, wastewater treatment process

摘要： 对西北某大型炼化企业炼油、化工两条污水处理流程的关键工艺环节进行水样采集，采用紫外可见光谱及吹扫捕集-气相色谱与质谱联用（GC-MS））解析了污水水样中挥发性有机成分的组成和含量的变化。共鉴定出有机物19类76种，化工污水当中的有机物（43种）相对炼油污水（32种）更加复杂。研究表明，炼油污水含较多的含硫化合物（硫醚、噻吩），是恶臭气体的主要来源；化工污水含较多的含氮化合物（硝基化合物、腈类、氰类），是氨氮及总氮的主要贡献者；芳香化合物种类多达数十种，对VOCs贡献较大。指出化工污水水解环节可产生部分醇、酮类化合物，提高后续污水可生化性。生化处理环节能去除污水中的绝大部分烷烃、烯烃、炔烃和少部分醇、酮；而芳香烃、多环芳烃、氯代烃生物降解性相对较差，生化后依旧具有残留，是污水处理COD残留的重要原因，可作为炼化特征有机污染物。提出分子水平的精细解析，能够为污水处理工艺评价提供科学依据，进而对工艺开发和工艺改进提供帮助。

关键词: 化学分析, 色谱, 排水, 挥发性有机物, 污水处理