Formation of Halonitromethanes and Nitrosamines During Ozonation in Drinking Water Treatment

饮用水处理中臭氧化过程中卤代硝基甲烷和亚硝胺的形成

• 批准号: 1066567
• 负责人: Tanju Karanfil
• 金额: $ 32.39万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-02-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1066567&HistoricalAwards=false
• 关键词: Formation; Halonitromethanes; Nitrosamines; During; Ozonation

PI: Tanju KaranfilProposal Number: CBET-1066567Institution: Clemson UniversityTitle: Formation of Halonitromethanes and Nitrosamines During Ozonation in Drinking Water TreatmentHalonitromethanes (HNMs) and nitrosamines constitute two important classes of disinfection byproducts (DBPs) that can form during water treatment. HNMs have orders of magnitude higher cytotoxicity and genotoxicity than any of the regulated organic DBPs, while nitrosamines pose cancer risk at very low levels (i.e., ng/L). The PI?s recent research has shown that HNM formation was significantly higher during ozonation-chlorination as compared with other typical disinfection scenarios used in drinking water treatment. It was also demonstrated that the HNM formation increased with an increase in dissolved organic nitrogen (DON) content in water. However, little is known about the role of DON components and the identity of precursors causing HNM formation. Furthermore, the formation of nitrosamines during ozonation is controversial. Though previous studies have shown that ozonation decreased N-nitrosodimethylamine (NDMA) formation, recent works have reported an appreciable amount of NDMA formation after ozonation in both lab studies and full scale ozonation plants. Therefore, it will be critically important to investigate the formation of HNMs and nitrosamines during ozonation, and to understand the factors controlling their formation and speciation.The PI seeks to systematically investigate formation of HNMs and nitrosamines during ozonation, and to gain insight to their potential precursors and formation mechanisms. We hypothesize that the formation of N-DBPs is precursor specific, and different precursors/ mechanisms will involve in the formation of HNM or nitrosamines. Therefore, in this study, various formation mechanisms have been postulated and experimental plans are proposed to investigate the proposed mechanisms. The PI and coworkers will initially perform experiments with a set of carefully selected model nitrogenous organic compounds (Task 1). Reaction intermediates will be analyzed to examine the proposed formation mechanisms and to gain insight to the formation of HNMs and nitrosamines (Task 2). A monitoring study (Task 3) in selected natural waters is also planned to examine the relationship(s) between the precursors(based on Task 2 and 3) and the DBPs (HNM or Nitrosamines). The proposed work is novel because it will be the first time that the proposed mechanisms will be investigated. The findings are expected to provide important information about the potential role(s) of different organic nitrogen components in natural waters in the formation of HNMs and nitrosamines during ozonation.Understanding the formation of HNMs and nitrosamines is vital for finding strategies to control these compounds. There are approximately 250 ozonation plants in the US, and some of them are quiet large (500-800 MGD), serving very large populations. Research results will provide important information for ozonation plants worldwide (e.g., ozonation is widely implemented in Europe). An appreciable number of utilities in the US have been exploring alternative approaches to comply with the stringent requirements of the Stage 2 D/DBP Rule. Ozonation is one of the available alternatives. Therefore, the findings will be important for utilities considering ozonation. The knowledge from this work will improve our understanding of the nature of HNM and nitrosamine formation and directly impact practitioner?s ability to control the formation of these compounds in treatment facilities. The USEPA and state regulatory agencies can benefit from the results in developing both present and future procedures for managing these compounds. Implementing this project will also promote training and education of a wide range of students with diverse backgrounds and levels. The PI will offer a Creative Inquiry research course through this project, a unique program of Clemson University bringing undergraduate students from different departments studying various disciplines to work in small team-projects and earn college credits. Participating students will learn about water treatment processes, applied chemistry (i.e., DPB formation) and how to conduct scientific research. The project will also allow opportunities for high school and undergraduate students, particularly from underrepresented groups.

主要研究者：Tanju KaranfilProposal编号：CBET-1066567机构：克莱姆森大学标题：饮用水处理中臭氧化过程中卤代硝基甲烷和亚硝胺的形成卤代硝基甲烷（HNM）和亚硝胺构成了水处理过程中可能形成的两类重要消毒副产物（DBP）。 HNM的细胞毒性和遗传毒性比任何受管制的有机DBP高几个数量级，而亚硝胺在非常低的水平下（即，ng/L）的浓度。 私家侦探？最近的研究表明，与其他典型的饮用水处理消毒方案相比，臭氧氯化过程中HNM的形成明显较高。 结果还表明，HNM的形成增加与水中溶解性有机氮（DON）含量的增加。 然而，很少有人知道的DON组件的作用和身份的前体导致HNM形成。 此外，在臭氧化过程中亚硝胺的形成是有争议的。 虽然以前的研究表明，臭氧化减少N-亚硝基二甲胺（NDMA）的形成，最近的工作已经报道了可观的NDMA形成后，在实验室研究和全面的臭氧化工厂。 因此，研究臭氧氧化过程中HNMs和亚硝胺的形成，了解其形成和形态的控制因素，对臭氧氧化过程中HNMs和亚硝胺的形成具有重要意义。本研究旨在系统地研究臭氧氧化过程中HNMs和亚硝胺的形成，并深入了解其潜在的前体和形成机理。 我们推测N-DBPs的形成是前体特异性的，不同的前体/机制将参与HNM或亚硝胺的形成。 因此，在这项研究中，各种形成机制已被假定和实验计划，提出了调查所提出的机制。 PI和同事将首先使用一组精心选择的模型含氮有机化合物进行实验（任务1）。 将分析反应中间体，以检查拟议的形成机制，并深入了解HNM和亚硝胺的形成（任务2）。 此外，亦计划在选定的天然沃茨进行监测研究（任务3），以研究前体（基于任务2及3）与消毒副产物（六硝基甲烷或亚硝胺）之间的关系。 拟议的工作是新颖的，因为这将是第一次，拟议的机制将进行调查。 这些研究结果将为了解臭氧氧化过程中天然沃茨中不同有机氮组分在HNMs和亚硝胺形成中的潜在作用提供重要信息，了解HNMs和亚硝胺的形成对于寻找控制这些化合物的策略至关重要。 美国大约有250个臭氧化工厂，其中一些非常大（500-800 MGD），服务于非常大的人口。 研究结果将为全球臭氧化工厂提供重要信息（例如，臭氧化在欧洲得到广泛应用）。 在美国，不少公用事业公司一直在研究其他方法，以符合第二阶段D/DBP规则的严格要求。 臭氧化是一种可行的替代方法。 因此，研究结果将是重要的公用事业考虑臭氧化。 这项工作的知识将提高我们对HNM和亚硝胺形成的性质的理解，并直接影响从业者？控制这些化合物在处理设施中形成的能力。 美国环保局和州监管机构可以从开发当前和未来管理这些化合物的程序的结果中受益。实施这一项目还将促进对具有不同背景和水平的各种学生的培训和教育。 PI将通过这个项目提供一个创造性的探究研究课程，这是克莱姆森大学的一个独特的项目，使来自不同部门的本科生学习不同学科，在小型团队项目中工作，并获得大学学分。 参与的学生将学习水处理过程，应用化学（即，DPB的形成）以及如何进行科学研究。 该项目还将为高中生和本科生，特别是代表性不足的群体提供机会。