Collaborative Research: GOALI: WRF: Securing the Future of Direct and Indirect Potable Reuse ? N-nitrosodimethylamine (NDMA) Formation Pathways and Precursors

合作研究：GOALI：WRF：确保直接和间接饮用水再利用的未来？

• 批准号: 1803955
• 负责人: Megan Plumlee
• 金额: $ 7万
• 依托单位: Orange County Water District
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-15 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1803955&HistoricalAwards=false
• 关键词: Collaborative; Research; GOALI; WRF; Securing

The use of disinfectants during water treatment has effectively eradicated waterborne illness, but these disinfectants form low concentrations of carcinogenic chemical by-products. These by-products tend to form at higher levels in disinfected wastewater, a complication that is usually alleviated by time in rivers, lakes, and aquifers that allows for the degradation of these carcinogenic chemicals. However, this time for degradation is reduced in potable water reuse scenarios, putting the future of potable water reuse technologies at risk. This project will investigate the mechanisms of and potential solutions to the formation of a carcinogenic chemical, N-nitrosodimethylamine (NDMA), during advanced treatment of wastewater targeted for potable reuse. The project will also enhance educational opportunities for students at the college and middle school level, and provide new educational and research infrastructure in a partnership between two industrial partners and a university. If successful, this research can further enable the use of potable water reuse, a valuable technology that could support our nation's water security. N-nitrosodimethylamine (NDMA) is a carcinogenic compound that forms during chloramine disinfection. NDMA precursors that enter drinking water treatment plants are thought to originate in wastewater. Based on ongoing NDMA precursor research, some technologies used in potable reuse systems have been identified as technologies that reduce NDMA occurrence and formation: reverse osmosis (RO), which physically removes precursors, and strong ultraviolet (UV) light, which photolyzes NDMA to nitrite and dimethylamine. While these systems effectively reduce NDMA formation by 90%, NDMA formation still occurs at physiologically relevant concentrations (5 ng/L) in the disinfected water. The sources of these precursors are unknown, but preliminary research indicated that the treatment processes themselves may release a new subset of NDMA precursors into the water. The overarching hypothesis of this research is: Advanced treatment for potable reuse contributes NDMA precursors to the finished water via leaching NDMA precursors from RO and/or transforming unreactive organic matter to NDMA precursors during UV, hydrogen peroxide (UV/peroxide) treatment. The rationale that underlies the research is that NDMA is highly carcinogenic, and while RO and UV/peroxide remove most NDMA precursors, they also change the water chemistry which may cause occurrence of new NDMA precursors. The hypothesis will be tested by pursuing 4 specific aims: 1) Determine the reactivity of known precursors and chemical additions in forming NDMA; 2) Identify UV/peroxide transformation products and kinetics that "up-convert" unreactive organic N to reactive, NDMA precursors; 3) Characterize changes in bulk chemical characteristics of the NDMA precursor pool during advanced water treatment; and 4) Identify operational changes that minimize NDMA formation at pilot-scale. These aims will be investigated using novel mass spectrometric and separations techniques pioneered by members of the research team.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在水处理过程中使用消毒剂有效地根除了水传播疾病，但这些消毒剂形成低浓度的致癌化学副产品。这些副产品往往在消毒废水中形成更高的水平，这是一种复杂的情况，通常会随着时间的推移而减轻，河流，湖泊和含水层允许这些致癌化学品的降解。 然而，在饮用水再利用的情况下，这种降解时间减少，使饮用水再利用技术的未来处于危险之中。该项目将调查在用于饮用水再利用的废水的深度处理过程中形成致癌化学物质N-亚硝基二甲胺（NDMA）的机制和潜在解决方案。该项目还将增加大学和中学学生的教育机会，并在两个工业伙伴和一所大学之间的合作伙伴关系中提供新的教育和研究基础设施。如果成功，这项研究可以进一步实现饮用水的再利用，这是一项有价值的技术，可以支持我们国家的水安全。N-亚硝基二甲胺（NDMA）是一种致癌化合物，在氯胺消毒过程中形成。进入饮用水处理厂的NDMA前体被认为来自废水。根据正在进行的NDMA前体研究，已确定饮用水再利用系统中使用的一些技术是减少NDMA发生和形成的技术：物理去除前体的反渗透和将NDMA光解为亚硝酸盐和二甲胺的强紫外线。虽然这些系统有效地将NDMA形成减少了90%，但在消毒水中，NDMA形成仍在生理相关浓度（5 ng/L）下发生。这些前体的来源尚不清楚，但初步研究表明，处理过程本身可能会向水中释放一种新的NDMA前体。本研究的总体假设是：饮用水再利用的高级处理通过从RO中浸出NDMA前体和/或在UV、过氧化氢（UV/过氧化物）处理过程中将不反应的有机物转化为NDMA前体，将NDMA前体贡献给成品水。该研究的基本原理是NDMA具有高度致癌性，虽然RO和UV/过氧化物可以去除大多数NDMA前体，但它们也会改变水的化学性质，从而可能导致新的NDMA前体的出现。该假设将通过追求4个具体目标进行测试：1）确定已知前体和化学添加物在形成NDMA中的反应性; 2）确定UV/过氧化物转化产物和将非反应性有机N "上转换"为反应性NDMA前体的动力学; 3）表征在高级水处理过程中NDMA前体池的大量化学特性的变化;和4）确定在中试规模下使NDMA形成最小化的操作变化。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。