Carol J. Miller

The re-eutrophication of Lake Erie: Harmful algal blooms and hypoxia

Lake Erie supplies drinking water to more than 11 million consumers, processes millions of gallons of wastewater, provides important species habitat and supports a substantial industrial sector, with >

Ultrasonic Testing for Compacted Clayey Soils

50 billion annual income to tourism, recreational boating, shipping, fisheries, and other industries. These and other key ecosystem services are currently threatened by an excess supply of nutrients, manifested in particular by increases in the magnitude and extent of harmful planktonic and benthic algal blooms (HABs) and hypoxia. Widespread concern for this important international waterbody has been manifested in a strong focus of scientific and public material on the subject, and commitments for Canada-US remedial actions in recent agreements among Federal, Provincial and State agencies. This review provides a retrospective synthesis of past and current nutrient inputs, impairments by planktonic and benthic HABs and hypoxia, modelling and Best Management Practices in the Lake Erie basin. The results demonstrate that phosphorus reduction is of primary importance, but the effects of climate, nitrogen and other factors should also be considered in the context of adaptive management. Actions to reduce nutrient levels by targeted Best Management Practices will likely need to be tailored for soil types, topography, and farming practices.

Characterization of humic substances in landfill leachate and impact on the hydraulic conductivity of geosynthetic clay liners

In this study, tests were conducted to investigate the use of ultrasonic methods to determine compaction characteristics of clayey soils. In particular, through-transmission test method was used to determine P-wave velocities in compacted clayey soils. Effects of soil type and compaction conditions on velocity were investigated. Tests were conducted on three soils that had low, medium, and high plasticity. Soils were prepared at water contents ranging from dry to wet of optimum using standard and modified compaction efforts. It was observed that velocity increased with increasing compactive effort and decreasing plasticity and clay content. Moreover, the variation of ultrasonic velocity with water content was similar to the variation of dry density with water content. Shapes of the water content versus velocity plots correlated well with the shapes of compaction plots. Access to two opposite surfaces of samples was required to perform through-transmission measurements. Additional tests were conducted to determine the feasibility of using surface-transmission with access required only to top surface of soils to measure velocity. Velocities that were similar to through-transmission velocities were obtained with surface measurements using correction factors. Through-transmission can be used in the laboratory; whereas surface-transmission can potentially be used in the field to determine ultrasonic velocity of compacted clayey soils. This method shows promise for determination of compaction properties of clayey soils in the field.

An integrated economic/emission/load profile management dispatch algorithm

A detailed characterization was performed on the humic substances present in landfill leachate derived from the older (10-year) and younger (6-month) municipal landfill cells at a site in Inchion, Korea. The characterization focused on the humic and fulvic acid components of the leachate, relying on information gleaned from the UV/visible spectroscopy, molecular weight distribution, and Fourier transform infrared spectroscopy. The effect of the leachates, and specific components of the leachates, on the hydraulic conductivity of a geosynthetic clay liner (GCL), was evaluated. The humic acid extracted from the older leachate was composed primarily of high molecular weight and aromatic compounds, which is typical for humic acids. However, the humic acid extracted from the younger leachate showed characteristics more similar with fulvic acids, indicating that the younger humic acid was at the initial stage of humification. The hydraulic conductivity of the GCLs to the humic and fulvic acids of the older and younger leachate was similar to those permeated with the distilled deionized water (DI). However, the hydraulic conductivity of the samples tested with the raw leachate was more than 200 times the DI value. This fact suggests that cations present in leachate, rather than humic substances, are the key factor in the increase of the permeability.

Data Quality and Failures Characterization of Sensing Data in Environmental Applications

Load profile management, among other load or demand side management (DSM) techniques, has been considered as an effective tool for power system operation and management. This paper introduces a load profile management program to be incorporated, along with the generation cost and emission constraints, in a dispatch algorithm to minimize the overall production cost over the period of the load profile management program. The algorithm has been implemented using Matlab optimization toolbox and tested on a 5-bus, 3-generator system. The simulation results are presented, compared and discussed for different scenarios with different levels of load management. The results show that the load management can help reduce generation costs and emissions.

Multiple sediment cores from reservoirs are needed to reconstruct recent watershed changes from stable isotopes (δ13C and δ15N) and C/N ratios: case studies from the mid-western United States

Environmental monitoring, targeting at discovering and understanding the environmental laws and changes, is one of the most important sensor network application domains. Environmental monitoring is one of the most important sensor network application domains. The success of those applications is determined by the quality of the collected data. Thus, it is crucial to carefully analyze the collected sensing data, which not only helps us understand the features of monitored field, but also unveil any limitations and opportunities that should be considered in future sensor system design. In this paper, we take an initial step and analyze one-month sensing data collected from a real-world water system surveillance application, focusing on the data similarity, data abnormality and failure patterns. Our major findings include: (1) Information similarity, including pattern similarity and numerical similarity, is very common, which provides a good opportunity to trade off energy efficiency and data quality; (2) Spatial and multi-modality correlation analysis provide a way to evaluate data integrity and to detect conflicting data that usually indicates appearances of sensor malfunction or interesting events; and (3) External harsh environmental conditions may be the most important factor on inflicting failures in environmental applications. Communication failures, mainly caused by lacking of synchronization, contribute the largest portion among all failure types.

Fractal dimension for the cracks of compacted clay liners in the landfill cover system in winter condition

Watershed land-use changes, including urbanization, have caused accelerated soil erosion, which in turn has increased sediment accumulation rates in most aging reservoirs in the mid-western United States (USA), thereby posing a threat to their longevity and productivity. We analyzed three sediment cores from each of two reservoirs in the mid-western USA, the Webber Dam impoundment in Michigan and Goshen Pond in Indiana. Core chronologies were established using 137Cs and 210Pb. Concentrations of organic carbon and nitrogen and their stable isotope compositions (δ13C and δ15N) were measured to investigate past land-use changes. We used three excess 210Pb-based (210Pbxs) sedimentation rate models (constant 210Pb flux and sedimentation, constant rate of supply of 210Pb and constant initial 210Pb concentration) to develop core chronologies and compared them to the chronology obtained from the 137Cs peak. Validation of the excess 210Pb-based chronology with137Cs-based chronology requires more than one 210Pbxs-based-model. That is, even in one watershed, output from more than one 210Pbxs-based model may have to be compared with an independent time marker. We compared C/N ratios, δ13C and δ15N among three time horizons in each of the three cores from the reservoirs (corresponding to dates of 1950, 1970 and 2010). Within a reservoir, there can be large differences between cores for a given time horizon, indicating there could be spatial differences in sources of C and N and the processes that influence carbon and nitrogen isotopes. We conclude that multiple sediment cores from reservoirs should be analyzed if carbon and nitrogen isotopes in sediments are to be used for paleoenvironmental inference.

A case study of energy cost optimization in Monroe water distribution system

The authors intend to show in this study, through the use of surface crack view, how a fractal approach might usefully model certain cracks in the surface. The use of a fractal model is an oversimplification. Nevertheless, the authors claim that we can not begin to solve more complex problems such as determining water movements in soil (or liner) before we first gain a deeper understanding of a simpler model of the sort described in this paper. As a result, fractal dimensions of four simulated cracks in the compacted clay liner by freezing/thawing effects were computed. The first two cracks analyzed appeared after the first freeze/thaw cycle while cracks #3 and #4 appeared after the second freeze/thaw cycle. Fractal dimensions between 1.12 and 1.23 have been measured for the four cracks.

A workshop on transitioning cities at the food-energy-water nexus

The most expensive part of operating water distribution system is the cost of energy required for pumping. With variable rate contracts, energy costs can vary during the day. As a result, the price of energy during peak demand is typically higher than other hours of a day. To save money and minimize user fees water distribution system may be able to shift energy usage to off-peak hours.

Linking load demands to power generation pollutant emissions based on locational marginal prices

Metropolitan development in the USA has historically relied on systems of centralized infrastructure that assume a population density and level of economic activity that has not been consistently sustained in post-industrial urban landscapes. In many cities, this has resulted in dependence on systems that are environmentally, economically, and socially unsustainable. Reliance on this deteriorating social and physical infrastructure results in waste and decreased efficiencies. While numerous cities could exemplify this trend, the present work highlights two compelling cases: Detroit, Michigan and Baltimore, Maryland. The paper provides important feedback from a recent workshop held with experts of both practical and academic backgrounds from both cities. The workshop focused on sustainability of the food-energy-water nexus within the context of transitioning urban landscapes, economies, and governance processes associated with post-industrial cities. The pursuit of environmental, economic, and social sustainability—especially in relation to food, energy, and water—is particularly challenging in aged and deteriorating post-industrial urban settings, and the importance of such cities to the global economy demands that attention be focused on research and education to support this mission. Given their age, geographic locations, and complex social-ecological histories, the examination and comparison of the cities of Detroit and Baltimore in the workshop described here provided a unique opportunity for evaluation of research, education and outreach needs, and opportunities in food, energy, and water (FEW) sustainability.