- Using UV/Peroxyacetic Acid to Remove Pharmaceuticals from Reclaimed Wastewater
- Investigating Changes of River Course of the Tennessee River and the Impact from Regional Climate Change
- Measuring Water Table Fluctuations under Different Irrigation Regimes in Western Tennessee Agroecosystems
- Urban Stream Restoration Planning: Towards Cost-Effective Mitigation of the Effects of Hydromodification
- Development of a Robust Model for Cross-Scale Prediction of Flow and Sediment Transport
- Environmental Impacts of Coal Ash Spill on Nutrient Cycling and Surface Water Quality in Eastern Tennessee
Project Number: 2016TN115B
Title: Using UV/Peroxyacetic Acid to Remove Pharmaceuticals from Reclaimed Wastewater
PI: John Buchanan, UTIA Biosystems Engineering and Soil Science
A reliable source of safe, clean water is a prerequisite for the production of fresh fruits and vegetables. Fresh produce is particularly susceptible to being contaminated by poor-quality water because it receives very little post-harvest processing and is often consumed raw. There is a strong consumer demand for fresh produce; the health benefits of fresh fruits and vegetables are well documented. A potential source of safe irrigation water is reclaimed water, or the use of highly-treated domestic wastewater. The assumption is that the wastewater would be free of suspended solids, has a very low oxygen demand, has no odors, and has no pathogens (tertiary treatment). A particular concern with this level of treatment is that many pharmaceutical compounds, such as hormones and antibiotics, are recalcitrant to the biological treatment process (oxygen demand reduction). Because of this concern, an additional level of wastewater treatment must be devised quaternary treatment the removal of trace organics to ensure the safe use of reclaimed water. Methods for trace organic compound removal include chemical oxidation (chlorine was mentioned above) and photo-oxidation (ultraviolet light). The objective of this project is to gain new knowledge about using a combination of oxidizers to remove certain trace organic compounds. Peroxyacetic acid (PAA) is strong oxidizer commonly used in Europe as a disinfectant. Ultraviolet light is gaining in popularity in the U.S. for providing disinfection. Each of this methods have advantages and disadvantages; by using these two methods in tandem there may be a symbiotic effect that improves the performance of both. The combination of chemical oxidizers and UV light is called Advanced Oxidation Processes (AOP). Most AOP research has been conducted on the H2O2/UV combination. This project proposes to use PAA as the chemical oxidizer. Commonly called peracetic acid (or ethaneperoxoic acid), this compound is the peroxide of acetic acid and is typically purchased as an quaternary equilibrium mixture containing acetic acid, hydrogen peroxide, peracetic acid and water. The peracetic acid solution has two peroxides hydrogen peroxide and peracetic acid. Peroxides are compounds that include a pair of oxygen atoms that are attached by a single covalent bond or O2-2. This is different from molecular oxygen that is a pair of double bonded oxygen atoms (O2). Peroxides are relatively unstable. The single-bonded oxygen pair is a higher energy state and so there is a strong tendency to revert back to molecular oxygen. This process makes peroxides strong oxidizers. Operating a UV source downstream from PAA injection can potentially break the chemical bond between the two oxygen atoms in PAA, and sequentially forms additional hydroxyl radicals. Hydroxyl radicals are strong oxidizers. A bench-scale, continuous-flow treatment system will be constructed to simulate point-of-use water treatment for the purpose of irrigation. Two concentrations (0.1 and 0.5 ppm) of four commonly-detected pharmaceutical compounds (17thinylestradiol, sulfamethoxazole, triclosan, and diclofenac) will be used to evaluate the treatment system performance. Two PAA injection rates will be used such to provide treatment concentrations of 1 ppm and 5 ppm. Likewise, UV exposure will be tested at two rates: approximately 35,000 and 50,000 W s cm-2. A full factorial of treatment combinations will be evaluated, including a non-treatment control, to study removal trace organic efficiency.
Project Number: 2016TN116B
Title: Investigating Changes of River Course of the Tennessee River and the Impact from Regional Climate Change
Team: Joshua Fu and Xinyi Dong, UT Civil and Environmental Engineering
Change of river course may significantly alter the water supply for agricultural farming, urban utility, and energy generation from dams. The Tennessee River provides water resource for multiple sates in Southeast US including Tennessee, Alabama, Mississippi, and Kentucky. Understanding the river course change of the Tennessee River is of special importance for the transboundary water management. But there has not been a systematic examination of river course change within the Tennessee River basin during the past decades. River course change is primarily driven by precipitation supply. In particular, massive runoff resulted from extreme precipitation may change the river course rapidly from year to year. Climate studies have indicated that extreme weather events such as heat wave and extreme precipitation are likely to intensify over North America in the future. So it is important to understand the impact of regional climate change on river course change during the past decade, and also probe into the potential changes of precipitation in the future. The investigation of regional climate impact on river course change can also provide information for water resource management or strategy design. We propose to investigate the changes of river course of the Tennessee River basin during the past 30 years from 1984 to 2014 with the Landsat satellite remote sensing product. The investigation will be conducted based on satellite products from Landsat. We will investigate the impact of regional climate change on river course based on modeling research with the National Centers for Environmental Protection (NCEP) reanalysis data, Community Earth System Model (CESM), and Weather Research and Forecasting (WRF) modeling system. The ground-based meteorology observations from National Climate Data Center (NCDC) will also be utilized to facilitate the analysis. We will also evaluate the potential impact of future climate change on precipitation over the Tennessee River basin, to provide support information for water resource management of the Southeastern US. The objective of this study is to improve of the knowledge about changes of river course of the Tennessee River during the past 30 years (from 1985 to 2014) to provide information for water source management.
Project Number: 2016TN117B
Title: Measuring Water Table Fluctuations under Different Irrigation Regimes in Western Tennessee Agroecosystems
Team: Christopher Wilson and Jon Hathaway, UT Civil and Environmental Engineering; Shawn Hawkins, UTIA Biosystems Engineering and Soil Science
The soil water balance is a prime control of the structure and function of agroecosystems, driving the dynamics of both the crops and soil microbial communities. However, maintaining the optimal level of soil moisture is increasingly a challenge, as weather patterns more frequently shift between extensive flooding and deep droughts. Exacerbating these complications are the stresses from encroaching urban areas in formerly agriculturally dominant landscapes. These projected changes, along with volatile corn prices, have prompted many farmers to consider irrigation in western Tennessee in hopes of maintaining high yield crops. In fact, there has been a ten-fold increase in the number of center-pivots between 2007 and 2012 in Tennessee, with the number of acres under irrigation increasing by about 40,000 each year. Irrigation has been shown to stabilize and even increase crop yields. In western Tennessee, this can translate to an extra 50 bushels per acre of corn or 300 additional pounds of cotton per acre. But, is irrigation truly sustainable? This is difficult to say, as the few measurements and predictions of water table fluctuations under irrigation schemes that are currently being made are insufficient for management level decision-making (i.e., are not adequate to be paired with economic models). As a result, a critical gap in our current monitoring and modeling capabilities is the lack of understanding about the interactions of soil moisture, infiltration, and pedology at different spatial and temporal resolutions and under different management practices. Such knowledge is important to quantify sufficiently water table fluctuations, especially in regions exhibiting high heterogeneity in landscape characteristics, to help us understand how irrigation impacts the available water resources and develop sensible water allocation plans for the region.
Project Number: 2016TN118B
Title: Urban Stream Restoration Planning: Towards Cost-Effective Mitigation of the Effects of Hydromodification
Team: Robert Woockman and John Schwartz, UT Civil and Environmental Engineering
In-stream channel degradation as a result of alterations to flow and/or sediment caused by urbanization can have detrimental ecological and socioeconomic impacts. Although steps have been taken to minimize these impacts through stormwater regulatory efforts, regulation typically takes the form of uniform volume control measures designed around a pre-disturbance condition. These uniform style regulations are often favored because the simplicity of implementation in a wide variety of municipal settings. Although implementation of such uniform regulations offers many conveniences for agencies, their effectiveness is not universal as a result of not integrating efforts with local stream system morphological attributes. Creating a scenario where additional costs may be imposed on the private sector, there is little or no improvement to externalities, and therefore social costs actually increase. This research proposes to integrate fluvial geomorphology concepts with engineering design and evaluate mitigation efforts through an economic framework. Hydrological modeling and field surveys are used to explore surrogate measures of eroding and resisting force with the intent to capture potential imbalances and define attributes that determine stability within the Ridge and Valley Province of Tennessee. Detailed in-situ flow monitoring was completed at three small stream systems to calibrate and validate coupled continuous simulation models of hillslope and in-channel processes. Models are utilized to explore response trajectory and efficacy of various mitigating suites with the intent to answer the following question: are cost effective mitigation strategies (intended to mitigate channel degradation in small stream systems) improved through consideration of stream channel erosive resistance elements? This research is expected to improve the body of knowledge available to municipalities as they move towards mitigating the impacts of urban hydromodification. Planning measures, which include an integrated systems approach, have the potential to improve channel protection flow design standards and guidance for in-lieu fee programs. This research is anticipated to result in three publications related to the topic discussed in the abstract. The central research questions that will be the focus of each article are listed below: What are the thresholds of destabilization, among 2nd and 3rd order stream reaches of the Ridge and Valley of Tennessee, and do these vary based on channel erosive resistance elements? Can the model platforms of SWMM & CONCEPTS be integrated successfully to represent Effective Work Regimes and the influence that channel erosive resistance elements and in- channel restoration practices have on regimes? Does the cost-effective BMP suite, for the purposes of mitigating channel instability due to urbanization, vary with consideration of channel erosive resistance elements and effective work performed on the channel? These questions are intended to improve our understanding of the linkages between urbanization, stormwater management policy, stream channel morphology, and degradational response over a range of watershed conditions and stream restoration practices. Although current research has made promising steps towards providing policy makers with adequate information and tools to cost effectively mitigate hydromodification effects, there remains a dearth of adequate information at regional levels. Therefore, it is the objective of this research to advance the available information necessary for cost effective mitigation strategies in the Ridge and Valley province of Tennessee. Through studying the interaction between increased eroding forces (due to hydrologic alteration) and resisting forces at the reach scale in 2nd and 3rd order streams.
Project Number: 2016TN119B
Title: Development of a Robust Model for Cross-Scale Prediction of Flow and Sediment Transport
Team: Benjamin Abban and Thanos Papanicolaou, UT Civil and Environmental Engineering
Current research objectives are to develop at state-of-the-art tool capable of simulating the transport of water and sediment from the plot scale to the watershed scale, while capturing important feedback effects across the scales. Such a tool is needed for effectively designing and monitoring practices for mitigating the impact of intensive management of landscapes by humans. Nearing the end of my PhD (expected in July, 2016), I have so far developed a coupled numerical model that links upland processes with in-stream processes in a dynamic fashion, and in addition is able to fully quantify uncertainty related to model predictions. The tool has been developed using several programming languages (C, C++, Fortran), statistical tools (OpenBUGS, R) and existing established models (3ST1D, WEPP). Several components of the tool have been presented in conferences, published as part of conference proceedings, or are in the process of being presented in a manuscript for peer-reviewed journals (see references below). The tool is a prime candidate for inclusion in the Community Surface Dynamics Modeling System (CSDMS), which is a collection of software for the earth science community to advance our understanding of earth surface processes. The tool, however, has one major bottleneck despite its utility. It is computationally demanding and so requires significant amount of time to perform a simulation. Thus, to further enhance the utility of the model and facilitate its ready adoption by the community, I am proposing to complete the following additional tasks for which I would like to be funded: Develop a parallel version of the tool that can run on everyday graphical processing units (GPUs) to considerably reduce computational time. Since most new desktops now are configured with GPUs, this enhancement should be well-received by the community. Present this novel work (in its entirety) to the earth science community at the upcoming European Geosciences Union (EGU) General Assembly in 2016, in hopes of getting valuable feedback from the entire community that can be used to further improve the tool and enhance our knowledge of cross-scale landscape processes. Publish the completed model in a peer-reviewed journal paper.
Project Number: 2016TN120B
Title: Environmental Impacts of Coal Ash Spill on Nutrient Cycling and Surface Water Quality in Eastern Tennessee
Team: Anna Szynkiewicz, UT Earth and Planetary Science
Coal ash is a waste product of coal burning in power plants to produce electricity. It contains verity of toxic metals that may contaminate locally surface waters used for drinking. Currently, there are 8 contaminated sites with coal ash disposal and 1 coal ash spill into surface water in Tennessee. However, research about environmental impacts of coal ash spills on the aquatic environment is still limited. Major objectives of this project are: 1) to evaluate water quality of Emory, Clinch and Tennessee rivers 8 years after the coal ash spill in Kingston, eastern Tennessee; 2) to determine if nutrient cycling via microbial sulfate reduction in the river bottom sediments can effectively immobilize toxic metals from coal ash spill due to formation of insoluble sulfides; 3) to determine changes of nutrient cycling (sulfur, carbon) in water column and sediments due to coal ash spill. Current contamination levels by toxic metals and impacts on nutrient cycling will be determined in the light of field and geochemical measurements that will include: pH, temperature, total dissolved solids, redox-oxidation potential, total dissolved oxygen, alkalinity, major cation and ion composition, and multiple sulfur-carbon-oxygen isotope analysis. This project has the potential to provide new, inexpensive, and relatively simple environmental tracers for state agencies and stakeholders in Tennessee and nationwide to evaluate the impacts of coal ash spills on surface water quality, nutrient cycling and metal bioremediation in contaminated sites.