Resuspension of E. coli in sediment laden streams

Soupir，MichelleCBET-0967845 PI提出了实验室实验来测量E.大肠杆菌从沉积物床和现场实验，以测试再悬浮的关系，从实验室的结果。 尽管以前的工作表明，沉积物扰动可以占总粪便污染的大部分，标准的水质模型不包括再悬浮的粪便细菌作为一个来源。 PI先前表明，包括沉积物和水柱之间的相互作用可以提高微生物浓度的预测，但由于大多数模型，包括细菌的再悬浮或者指定再悬浮率或校准作为一个功能，只有排放，更好的方法来预测再悬浮是必要的。 所提出的工作的主要好处是能够识别，控制和隔离影响再悬浮的参数，以便可以开发和测试预测再悬浮的关系。本研究的主要目的是：（1）测定E.（2）建立了预测附着和未附着大肠杆菌再悬浮的关系;大肠杆菌作为一个功能的流量和沉积物的属性，和（3）评估的关系，在现场收集的数据。 他们假设（a）附着的E.大肠杆菌的再悬浮率与沉积物的再悬浮率成正比，因为水柱中的附着分数与沉积物床中的附着分数相同;大肠杆菌在比附着的E.杆菌 这些假设被封装在一个基于物理的，定量的框架提出来预测再悬浮。所提出的研究的智力价值来自于隔离和控制影响再悬浮的重要参数的能力。 通过三种类型沉积物的实验室实验，将首次测量E。大肠杆菌再悬浮，其中流速和沉积物性质系统地变化。 从实验室实验的数据将被用来测试和发展物理基础的关系，以预测再悬浮的E。大肠杆菌作为一个功能的属性的流量，沉积物，和有机体。 为了测试来自现场实验室实验的公式，再悬浮率计算的质量平衡应用到一个达到的斯阔溪在艾姆斯，IA将进行比较的预测。 由此产生的基于物理的关系将是重要的，减少水质模型的参数化，和实验室实验将提供一系列的条件下，这将有助于指导我们的结果在水质建模的应用信息。初步结果表明，水槽试验对研究沉积物再悬浮具有重要意义。杆菌更广泛的影响包括培训一名研究生和一名本科生;对学校进行外联;指导一名新的助理教授;帮助负责制定每日最大总负荷的爱荷华州自然资源部将研究结果纳入流域尺度水质模型，以制定更切合实际的负荷分配;并与艾姆斯水和污染控制区合作，该地区正在考虑为爱荷华州艾姆斯的污水处理厂增加消毒。 对E.在溪流中的大肠杆菌将改善对人类健康可能面临风险的条件的预测，并实施土地管理措施，以减少全国的细菌污染？的水体。

Soupir, MichelleCBET-0967845The PI proposes laboratory experiments to measure resuspension of E. coli from a sediment bed and field experiments to test the resuspension relationships developed from the laboratory results. Even though previous work suggests that sediment disturbance can account for the majority of total fecal contamination, standard water quality models do not include resuspension of fecal bacteria as a source. The PI previously showed that including interactions between the sediment and the water column can improve predictions of microbial concentrations, but because most models that include resuspension of bacteria either specify a resuspension rate or calibrate as a function of only discharge, better ways to predict resuspension are needed. The main benefit of the proposed work is the ability to identify, control, and isolate the parameters affecting resuspension so that relationships to predict resuspension can be developed and tested. The objectives of the proposed work are to (1) measure the resuspension of E. coli in controlled laboratory experiments, (2) develop relationships to predict resuspension of attached and unattached E. coli as a function of properties of the flow and sediment, and (3) assess the relationships with data collected in the field. They hypothesize that (a) the resuspension rate of attached E. coli will be proportional to the resuspension rate of sediment because the attached fraction in the water column will be the same as that in the sediment bed and (b) resuspension of unattached E. coli will occur at lower shear stresses than for attached E. coli. These hypotheses are encapsulated in a physically based, quantitative framework proposed to predict resuspension. The intellectual merit of the proposed research comes from the ability to isolate and control important parameters affecting resuspension. Laboratory experiments with flow over three types of sediment will provide the first measurements of E. coli resuspension in which flow rates and sediment properties are varied systematically. Data from the laboratory experiments will be used to test and develop physically based relationships to predict resuspension of E. coli as a function of properties of the flow, sediment, and organisms. To test the formulas derived from laboratory experiments in the field, resuspension rates computed from a mass balance applied to a reach of Squaw Creek in Ames, IA will be compared to the predictions. The resulting physically based relationships will be important for reducing the parameterization of water quality models, and the laboratory experiments will provide information over a range of conditions that will help to guide the application of our results in water quality modeling. Preliminary results, as well as previous work on sediment resuspension, show that the flume experiments will be useful for studying resuspension of E. coli. The broader impacts include training a graduate student and undergraduate student; conducting outreach to schools; mentoring a new assistant professor; helping the Iowa Department of Natural Resources, which is responsible for developing total maximum daily loads, to incorporate the research results into watershed scale water quality models to develop more realistic load allocations; and collaborating with the Ames Water and Pollution Control District, which is considering adding disinfection to the wastewater treatment plant in Ames, Iowa. Careful measurements and improved models of the fate and transport of E. coli in streams will improve predictions of conditions where a risk to human health is likely and the implementation of land management practices to reduce bacterial pollution in the nation?s water bodies.