Mary Leigh Wolfe

Environmental statistical process control using an augmented neural network classification approach

Abstract Shifts in the values of monitored environmental parameters can help to indicate changes in an underlying system. For example, increased concentrations of copper in water discharged from a manufacturing facility might indicate a problem in the wastewater treatment process. The ability to identify such shifts can lead to early detection of problems and appropriate remedial action, thus reducing the risk of long-term consequences. Statistical process control (SPC) techniques have traditionally been used to identify when process parameters have shifted away from their nominal values. In situations where there are correlations among the observed outputs of the process, however, as in many environmental processes, the underlying assumptions of SPC are violated and alternative approaches such as neural networks become necessary. A neural network approach that incorporates a geometric data preprocessing algorithm and identifies the need for increased sampling of observations was applied to facilitate early detection of shifts in autocorrelated environmental process parameters. Utilization of the preprocessing algorithm and the increased sampling technique enabled the neural network to accurately identify the process state of control. The algorithm was able to identify shifts in the highly correlated process parameters with accuracies ranging from 96.4% to 99.8%.

Work in progress - spiral curriculum approach to reformulate engineering curriculum

A theme-based spiral curriculum approach is being adopted to initiate the department-level reform (DLR) of the freshman engineering and the bioprocess engineering curricula at Virginia Tech. A large number of engineering faculty members are collaborating with experts in educational psychology and academic assessment to accomplish the objectives of this 3-year NSF supported project that began in September 2004. Successful implementation of the spiral approach will be used as a model for incorporating similar reforms in other engineering departments and elsewhere

Assessing the Effects of Climate Change on Waterborne Microorganisms: Implications for EU and U.S. Water Policy

ABSTRACT Despite advances in water treatment, outbreaks of waterborne diseases still occur in developed regions including the United States and Europe Union (EU). Water quality impairments attributable to elevated concentrations of fecal indicator bacteria, and associated with health risk, are also very common. Research suggests that the impact of such microorganisms on public health may be intensified by the effects of climate change. At present, the major regulatory frameworks in these regions (i.e., the US Clean Water Act [CWA] and the EU Water Framework Directive [WFD]), do not explicitly address risks posed by climate change. This article reviews existing U.S. and EU water quality regulatory legislation for robustness to climate change and suggests watershed modeling approaches to inform additional pollution control measures given the likely impacts on microbial fate and transport. Comprehensive analysis of future climate and water quality scenarios may only be achievable through the use of watershed-scale models. Unless adaptation measures are generated and incorporated into water policy, the potential threat posed to humans from exposure to waterborne pathogens may be amplified. Such adaptation measures will assist in achieving the aims of the EU WFD and US CWA and minimize impacts of climate change on microbial water quality.

Community DECISIONS: stakeholder focused watershed planning.

Successful watershed planning can be enhanced by stakeholder involvement in developing and implementing plans that reflect community goals and resource limitations. Community DECISIONS (Community Decision Support for Integrated, On-the-ground Nutrient Reduction Strategies) is a structured decision process to help stakeholders evaluate strategies that reduce watershed nutrient imbalances. A nutrient accounting algorithm and nutrient treatment database provide information on nutrient loadings and costs of alternative strategies to reduce loadings. Stakeholders were asked to formulate goals for the North Fork Shenandoah River Watershed in Virginia and select among strategies to achieve those goals. The Vector Analytic Hierarchy Process was used to rank strategies. Stakeholders preferred a Maximum strategy that included point source upgrades, riparian buffers, no-till corn silage, wheat cover, and bioretention filters in developed areas. Participants generally agreed that the process helped improve communication among stakeholders, was helpful for watershed planning, and should be used for TMDL (Total Maximum Daily Load) planning. Participants suggested more attention be paid to ensuring that all relevant issues are addressed and all information needed to make decisions is available. Watershed planning should provide stakeholders with clear scientific information about physical and socioeconomic processes. However, planning processes must give stakeholders adequate time to consider issues that may not have been addressed by existing scientific models and datasets.

Particle size impacts of subsurface-banded urea on nitrogen transformation in the laboratory

Replacing commercial urea granules (0.01–0.02 g) with urea pellets (1.5 g) could improve crop yield and reduce nitrogen (N) losses into the environment. Since urea particle size affects N transformations and, subsequently, N-loss pathways, laboratory studies were conducted to study the effects of subsurface-banded urea particle size or specific surface area (SSA) effects on dissolution, mechanism of dissolved urea movement, and N mineralization (urea hydrolysis and nitrification). To simulate subsurface banding, urea treatments were applied in a plane beneath the soil to Ross loam soil at volumetric soil moisture content (θv) of 31.4% (34 cbars) in all studies. At 50% dissolution, granules dissolved eight times faster than 1.5-g pellets. Molecular diffusion was likely the predominant mechanism of dissolved urea movement in both pellets and granules. Urea hydrolysis was significantly lower by 3.1% in 1.5-g pellets than in granules after 7 d. At 35 d, nitrification rate of the applied-N was 11% (significantly) lower in 1.5-g pellets than granules. Compared with granules, pellets dissolved slower and inhibited both urease and nitrifier activity to a greater extent; however, nitrification inhibition was likely the predominant mechanism that reduced nitrate availability for both uptake and loss. Hence, when granules and 1.5-g pellets are both subsurface-banded in the soil, slower nitrification in pellets could reduce the potential for N losses. However, greater benefits in terms of increased crop yield and N uptake and, potentially, reduced N losses are likely when surface-broadcast urea granules are replaced with subsurface-applied urea pellets.

TMDL Modeling of Fecal Coliform Bacteria with HSPF

Fecal coliform TMDLs were developed for nine watersheds in Virginia using the HSPF model. The primary HSPF algorithms used to simulate FC loading and fate in the models are described in detail. Parameter values are summarized for all HSPF parameters related to FC simulation, as well as source data used external to the model for developing input loads from the various individual FC sources. Although there are many areas of uncertainty in modeling fecal coliform, a scientific approach was used in the evaluation of sources, the representation of the sources, and the evaluation of parameters used to simulate fecal coliform fate and transport with the HSPF model for nine sub-watersheds. The similarity of source reductions called for in each of the nine TMDLs support recommendations for the regional application of key results from TMDL studies to watersheds with similar sources and for the use of adaptive implementation as presented in a recent National Research Council report to Congress assessing the scientific basis of TMDLs (NRC, 2001).

Sensitivity of streamflow and microbial water quality to future climate and land use change in the West of Ireland

This study applied catchment modeling to examine the potential effects of climate change and future land management variations on streamflow and microbial transport sensitivities for two locations in the west of Ireland (Black River and Fergus River). Simulations focused on plausible combined scenarios of climate, population and agricultural production variations for the 2041–2060 period and compares resultant impacts to a baseline existing period (1994–2007). The variations in monthly, seasonal and annual streamflow, and the daily microbial load (for E. coli) were used to assess sensitivities. Results indicate that possible future changes in microbial load for both the Fergus and Black catchments typically follow projected seasonal fluctuations in precipitation and streamflow. Increased winter rainfall (intensity and frequency) will cause significant impacts on microbial transport, representing a period of increased risk. An increase in microbial source loads to land, concomitantly with projected changes in climate is likely to exert greater microbial pollutant pressures on surface waters. The simulated scenarios, and resultant microbial load changes, suggest that future variations in land use/management may be as important as the effects of climate change on in-stream microbial pollutant loads. Outcomes from this study can prove useful for informing water resource managers and other decision makers about potential impacts. This information can instigate the development of adaptation measures needed to alleviate increased catchment pollution from microbial contaminants (and other pollutants) in future years.

Work in Progress: Using e-Portfolio to Define, Teach, and Assess ABET Professional Skills

While most engineering programs are confident developing specific criteria and assessment tools for the technical skills described in ABET Criterion 3a-k, the question of how to define, teach and assess the professional outcomes (teamwork, professional and ethical responsibility, communication, impact of engineering solutions, life-long learning, and contemporary issues) remains much more challenging. This paper will describe expectations that connect student work to professional skills, broken down by level and organized into ePortfolio assessment matrices. The authors drew on two well-known learning paradigms: Blooms taxonomy and Baxter Magoldas schema of Intellectual Development. Changes resulting from consulting with an external assessor are discussed. Finally, the paper will conclude with a series of problems and answers in using this digital tool to meet the divergent goals of students, faculty, and program administrators

Community DECISIONS (Community Decision Support for Integrated, On-the-ground Nutrient Reduction Strategies)

Successful watershed management can be enhanced by effective stakeholder involvement. Community DECISIONS (Community Decision Support for Integrated, On-the-ground Nutrient Reduction Strategies) was designed to assist watershed stakeholders in evaluating and selecting strategies to reduce watershed nutrient imbalances. The decision process begins with stakeholders formulating objectives for the watershed. Through the Vector Analytic Hierarchy Process (AHP), stakeholders rank the objectives. Alternative nutrient management strategies are simulated using a nutrient accounting algorithm and nutrient treatment database. Based on nutrient loadings and implementation costs estimated for each strategy, stakeholders determine which strategies best achieve their objectives.

Assessing the impacts of climate change on waterborne microorganisms

Scientific research suggests that the impact of pathogens, such as verotoxigenic (VTEC) Escherichia coli and Cryptosporidium, may be intensified by the potential effects of climate change. It is predicted that extremes of the hydrological cycle will accompany global warming and both are likely to affect the nature of pathogens in the environment and their fate and transport. Regulations, such as the EU Water Framework Directive and the US Clean Water Act, highlight the need for models capable of predicting fecal pathogen fluctuations from watersheds with varying land uses. Previous research work on the applicability of watershed models to simulate daily pathogen concentrations has indicated that sufficient capabilities exist to model pathogen transport; however, additional research is required to account for future climate variability and identify risk scenarios. Integration of watershed-pathogen modeling capabilities with climate change predictions can enable investigation into the potential impacts on pathogenic organisms. To date legislations, such as the Clean Water Act in the USA and the Water Framework Directive in Europe, have failed to take direct account of the risks posed by climate change. The objective of this study is to examine potential climate change impacts on pathogens and assess the use of watershed-pathogen modeling applications to prepare for future scenarios. Deriving relevant scenarios and simulation of these through watershed modeling applications can provide the basis to develop appropriate remediation measures in preparation for climate impacts on waterborne microorganisms.