污水处理厂中磷系阻燃剂浓度分布及归趋研究

发布时间：2018-03-01 16:10

本文关键词： 污水处理磷系阻燃剂环境归趋　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：作为溴代阻燃剂的替代品,磷系阻燃剂被广泛地作为阻燃剂和增塑剂使用。长距离大气运输的能力以及持久性使其在在全球范围内广泛存在于各类环境介质中。污水处理厂是磷系阻燃剂的重要环境归趋,如果处理不当,也有可能成为磷系阻燃剂的污染源。国际尤其是国内对于污水处理厂中磷系阻燃剂没有系统的研究,对它的环境多介质分布归趋研究尚不完善,本文将针对磷系阻燃剂在污水厂内污水、污泥及大气中的浓度及分布情况深入探讨磷系阻燃剂在污水处理系统中的归趋并运用环境多介质逸度模型对其进行模拟和验证。本课题采集哈尔滨市某污水厂不同流程处的水样,泥样和大气样品,通过回收率实验对比多种萃取和净化方法进行预处理方法的优化,最终确定液液萃取、震荡萃取和索式提取的方法分别对污水、污泥和大气样品进行预处理,用GC-MS对目标物进行检测。本课题还采用厌氧生物污泥法进行厌氧微生物对于磷系阻燃剂去除效果的实验室模拟。本研究中的7种目标物在污水厂中有6种被检出,TPr P低于检出限,进水中磷系阻燃剂总量为1180ng/L,TEHP浓度最大;出水中磷系阻燃剂总量523ng/L,其中TCEP浓度最大。我国污水厂中磷系阻燃剂污染在国际上仍然处于低等水平。A/O工艺和BAF工艺对EHDP和TEHP的去除都达到了90%以上,而氯代的磷系阻燃剂在污水处理过程中基本没有得到去除。厌氧污泥对磷系阻燃剂的降解效率不高,24h只有16.3%被降解。而污水厂的水力停留时间一般不超过24小时,所以污水厂中的磷系阻燃剂很难被活性污泥降解去除。厌氧污泥对TEHP和氯代的TCEP、TCPP的降解效率极低,这是由于三者结构上相似的位阻效应可能会在空间上阻碍水解酶的攻击进而延缓磷系阻燃剂的初级降解,而且TEHP极低的水溶性和很强的吸附趋势也降低了自身的生物利用度,使其难被降解。应用污水厂逸度模型对磷系阻燃剂在污水厂中的归趋进行模拟,模拟结果与实际检测数据拟合较好,通过灵敏度分析发现溶解度对整个模型的输出结果中的各个归趋途径都有显著影响。模型对污水厂各处理单元内污染物质的半衰期有一定的不确定性,而且物质在污水厂各介质间的传输系数需要根据不同污染物的理化性质进行反复校正,模型还需要进一步优化。
[Abstract]:As an alternative to brominated flame retardants, Phosphorous flame retardants are widely used as flame retardants and plasticizers. The ability and persistence of long-range atmospheric transport make them widely available in all kinds of environmental media on a global scale. Sewage treatment plants are important environmental trends for phosphorous flame retardants, If it is not treated properly, it may also become a source of pollution of phosphorous flame retardants. There is no systematic research on phosphorus flame retardants in sewage treatment plants, especially at home and abroad, and the study on the environmental multi-medium distribution of phosphorus flame retardants is not perfect. In this paper, for the phosphorus flame retardant in the sewage treatment plant, The concentration and distribution of sludge and atmosphere; the fate of phosphorous flame retardant in sewage treatment system and its simulation and verification by using environmental multimedium fugacity model. Water samples from the same process, Mud samples and atmospheric samples were pretreated by comparison of various extraction and purification methods through recovery experiments. The methods of liquid-liquid extraction, oscillating extraction and cable extraction were determined to pretreat sewage, sludge and atmospheric samples, respectively. GC-MS was used to detect the target. The anaerobic biological sludge method was also used to simulate the removal effect of phosphorus flame retardants by anaerobic microorganisms. Six of the 7 targets in this study were detected in wastewater treatment plants. TPr P was lower than the detection limit. The total amount of phosphorous flame retardant in the influent was 1180ng / L ~ (-1) TEHP concentration. The total amount of phosphorous flame retardants in effluent is 523ng / L, of which TCEP concentration is the largest. The removal of EHDP and TEHP in the domestic wastewater treatment plants is still at a low level at the international level. A- / O process and BAF process have achieved more than 90% removal of EHDP and TEHP. However, chlorinated phosphorous flame retardants have not been removed in the process of sewage treatment. The degradation efficiency of phosphorus flame retardants in anaerobic sludge is not high, only 16.3% of them have been degraded in 24 hours, and the HRT of wastewater treatment plants is generally less than 24 hours. Therefore, phosphorus flame retardants in wastewater treatment plants are difficult to be degraded by activated sludge. The degradation efficiency of anaerobic sludge to TEHP and chlorinated TCEP is extremely low. This is due to the fact that the similar steric resistance effect of the three structures may hinder the attack of hydrolase in space and delay the primary degradation of phosphorous flame retardants. Moreover, the extremely low water solubility and strong adsorption tendency of TEHP also reduce its bioavailability. The fugacity model of wastewater treatment plant is used to simulate the fate of phosphorous flame retardant in wastewater treatment plant. Through sensitivity analysis, it is found that solubility has a significant effect on all the regression pathways in the output of the whole model, and the model has some uncertainty on the half-life of pollutants in each treatment unit of the wastewater treatment plant. Moreover, the transfer coefficient of matter in the medium of wastewater treatment plant needs to be adjusted repeatedly according to the physical and chemical properties of different pollutants, and the model needs to be further optimized.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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