Quantification of Unintentional Water Recycling in Surface Waters

0303627赛德拉克在分析化学方面的最新进展导致在城市废水中检测到许多以前被忽视的化学污染物。虽然这些废水衍生污染物的存在导致了对使用经过高度处理的废水来增加供水的项目的相当严格的审查，但很少有人注意到废水流出物的无意回收。20世纪70年代进行的一项调查结果表明，在一年中的某些时间里，超过770万美国居民从废水来源获得水，这些来源中有50%以上是废水。由于人口持续增长，特别是在干旱地区，目前接受受废水影响的水的人数可能会更高。由于许多废水来源的污染物在水处理过程中不会被去除，这一途径可能会导致大量人群暴露在致癌或内分泌干扰的化学物质中。智力价值本项目的目标是评估当前废水流出物无意循环的程度，并开发可用于评估水供应中废水来源污染物的潜在存在的工具。这些目标将通过水文建模和实地测量相结合来实现。在该项目的第一阶段，将确定非故意回收可能重要的地点，并将在地表水中发现的条件下评估一套保守的和反应性示踪剂。水文分析将包括估计在平均和低流量条件下饮用水取水口废水流出量的比例，以及水在抽取之前在河流中停留的时间。在这一初步分析的基础上，将在项目第二阶段选择三个地点进行进一步分析。在每个站点，水文模型将使用特定站点的数据进行改进，包括河流地貌、降雨量和污染物衰减率。该模型的预测将与在整个分水岭贡献地区进行的保守和反应性示踪剂的测量进行比较。模型预测和测量之间的差异将被用来改进模型，并获得更好的污染物衰减率估计。广泛影响除了为无意回收废水所带来的风险提供新的见解外，该项目还将通过为来自代表不足群体的学生提供新的研究机会，对科学和工程产生广泛影响。在研究的第一阶段，来自表现不佳的当地学校的高中生将帮助收集必要的数据，以确定哪些地方的无意回收是重要的。在该项目的第二阶段，来自代表性不足群体的本科生将协助实地工作和数据分析。

0303627 Sedlak Recent advances in analytical chemistry have led to the detection of numerous previously ignored chemical contaminants in municipal wastewater effluent. While the presence of these wastewater-derived contaminants has led to considerable scrutiny of projects in which highly treated wastewater is used to augment water supplies, little attention has been paid to the unintentional recycling of wastewater effluent. Results of a survey conducted during the 1970s suggested that over 7.7 million U.S. residents receive water from sources that consist of more than 50% wastewater effluent during some portion of the year. As a result of continued population growth, especially in arid regions, it is likely that the current number of people receiving wastewater-impacted water is even higher. Because many wastewater-derived contaminants are not removed during water treatment, this pathway could result in exposure of large populations to chemicals that are carcinogens or endocrine disrupters.Intellectual MeritThe objective of this project is to assess the current extent of unintentional recycling ofwastewater effluent and to develop tools that can be used to assess the potential presence of wastewater-derived contaminants in water supplies. These objectives will be accomplished through a combination of hydrologic modeling and field measurements. In the first phase of the project, locations where unintentional recycling is likely to be significant will be identified and a suite of conservative and reactive tracers will be evaluated under conditions found in surface waters. The hydrologic analysis will include estimation the fraction of wastewater effluent at drinking water intakes during average and low-flow conditions and the amount of time the water has spent in the river prior to abstraction. On the basis of this preliminary analysis, three sites will be chosen for further analysis during the second phase of the project. At each site, the hydrologic model will be refined using site-specific data including river morphology, precipitation and contaminant attenuation rates. Predictions from the model will be compared with measurements of conservative and reactive tracers made at locations throughout the contributing areas of the watershed. Discrepancies between model predictions and measurements will be used to refine the models and to obtain a better estimate of contaminant attenuation rates.Broader ImpactsIn addition to providing new insight into the risks posed by the unintentional recycling ofwastewater effluent, the project will have a broad impact on science and engineering byproviding new research opportunities for students from underrepresented groups. During the first phase of the research, high school students from low-performing local schools will assist in the collection of data needed to identify sites where unintentional recycling is significant. During the second phase of the project, undergraduate students from underrepresented groups will assist in field work and analysis of data.