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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Implementing best management practices in small commercial and non-commercial animal enterprises

Godwin, Derek C. 24 February 1994 (has links)
Small commercial and non-commercial animal enterprises (SCAEs) raise a few beef cows, horses, pigs, sheep, poultry, and other animals on a few acres. These enterprises are often located in suburban areas of watersheds and show potential for degrading water quality through to increased bacterial, nitrogen, and phosphorus concentrations. SCAEs implement Best Management Practices (BNIPs) on a voluntary basis to control their water quality impacts. Off-stream watering areas, with animal access to streams, and covered manure storages are two BMPs which were analyzed in this thesis for effectiveness in reducing bacteria, nitrogen, and phosphorus from entering surface and groundwater in four SCAEs. The four cooperating SCAEs were located in the Tualatin River Basin, and the potential water quality improvements from implementing these two practices in all SCAEs in the basin were discussed. The BMP analyses use results from several studies. Two of these studies analyzed off-stream watering areas for reducing time animals spend watering at the stream. This time was measured and used to estimate the manure defecated in the stream. Reducing time animals spend at the stream decreases direct defecations in the stream and reduces water quality impacts of SCAEs. A third study analyzed a pasture pump as a possible off-stream watering device. It was analyzed for its ability to provide water to 27 Holstein dairy heifers without limiting water consumption. Daily water consumption from the pasture pump was not significantly different than daily consumption from an open water trough. A fourth study predicted the rainfall required to produce runoff from pastured areas in the Dairy-McKay Hydrological Unit Area within the Tualatin River Basin. These required rainfall amounts and runoff frequency were predicted for summer and winter soil conditions. The BMPs were analyzed for a variety of wet and dry conditions during the summer and winter. Off-stream watering areas were most effective in reducing water quality impacts of SCAEs for dry conditions during the summer and winter, while the covered manure storages were most effective during winter days of continuous rain. Off-stream watering areas reduced the time animals spent at the stream by 75%. Consequently, defecations at the stream were assumed to be reduced 75% and the SCAEs'water quality impacts decreased. Covered manure storages protect manure piles from rain and surface water runoff and prevent bacteria and nutrients from entering the stream or leaching to groundwater regardless of the weather. However, the amount prevented varies with weather conditions. An uncovered manure pile was estimated to cause no water quality impacts during dry weather. During wet weather, the bacteria and nutrients reaching the stream from an uncovered manure pile was estimated to be 60% of the quantity released. The maximum amount of nitrogen leaching to groundwater was estimated to be 10% of the amount applied to the pile since the previous rain. In addition to implementation costs of BMPs, there are changes in annual revenue and costs associated with the management changes. Partial budget analyses were conducted for the four SCAEs to determine their changes in annual monetary returns to management. Both BMPs resulted in negative changes in annual returns to management for all four enterprises. / Graduation date: 1994
2

Predicting nitrate concentrations in leachate resulting from land application of wastewater onto various crop systems including poplars

Motte, Marie Quitterie 23 September 1997 (has links)
Land application of industrial wastewater with high levels of nitrogen requires adequate management practices to prevent groundwater pollution by nitrates. In this study a predictive computerized model was developed for nitrate leachate concentrations resulting from land application of wastewater onto crop systems including poplars. The study included a literature review, development of a computer program that could serve this purpose, and a field investigation to test the validity of the computed predictions. The literature review focused on poplar water and nitrogen uptakes, and suggested that mature poplars could uptake up to 400 lb of nitrogen /acre/year and 2 3 million gallons of water per acre per year. The computer model, based on 10-day water and nutrient balances, takes into account a number of parameters such as wastewater quality, evapotranspiration and precipitation data, irrigation volumes, soil water holding capacities, fertilization, crop nutrient uptakes and crop coefficients. This study involves a number of assumptions selected to give conservative (i.e., worst case approach) model predictions. Attempts to validate the model were conducted through soil and groundwater sampling along with precipitation data collection in four distinct fields in Brooks, Oregon, from October 1996 to April 1997. The variations in nitrogen soil profiles from October to April helped determine the amount of nitrogen leaving the soil, and groundwater samples from 5 feet deep wells gave nitrate concentrations in groundwater below the root zone. A sensitivity analysis of the program demonstrated how important nitrogen and water uptakes values were to the model predictions. An increase of 1% in nitrogen uptake or of 0.4% in crop coefficients generated 1% decrease in nitrogen concentration of the leachate. These results are important to consider when adopting highly uncertain literature values for crop uptakes -especially with poplars. The field validation of the model showed promising results in terms of estimating average yearly leachate concentrations in nitrogen resulting from land application of wastewater, but also suggested that more groundwater wells were needed to obtain a statistically significant validation of the model. These preliminary field results indicate that the model can provide an indication of groundwater nitrogen concentration trends but needs to further verified to be used confidently as a predictive tool. / Graduation date: 1998
3

Collection and analyses of physical data for deep injection wells in Florida

Unknown Date (has links)
Deep injection wells (DIW) in Florida are regulated by the U.S. Environmental Protection Agency (USEPA) and the state of Florida through the Underground Injection Control regulations contained within the Safe Drinking Water Act. Underground injection is defined as the injection of hazardous waste, nonhazardous waste, or municipal waste below the lowermost formation containing an underground source of drinking water within one-quarter mile of the wellbore. Municipalities in Florida have been using underground injection as an alternative to surface disposal of treated domestic wastewater for nearly 40 years. The research involved collecting data as of September, 2007 on all the Class I DIWs in the state of Florida and evaluating the differences between them. The analysis found regional differences in deep well practice and canonical correlation analyses concluded that depth below the USDW is the most significant factor to prevent upward migration of the injected fluid. / by Jie Gao. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.
4

Les éco-industries : théorie de la firme et politiques optimales

Sans, Damien 20 November 2017 (has links)
Cette recherche s'intéresse à la modélisation des éco-industries et aux propriétés qui leurs sont généralement attribuées. Précisément, mettre l'accent sur les éco-industries requiert de faire des suppositions dont les conséquences ne sont pas triviales. Ce travail détaille ces conséquences ainsi que la pertinence de certaines. Le premier chapitre considère des éco-industries polluantes, alors que l'analyse économique sur ce sujet assume généralement que les biens et services environnementaux suppriment les polluants. Ce chapitre montre le mécanisme par lequel le marché distribue une activité aux éco-industries en fonction de leur technologie. Le deuxième chapitre enquête sur les limites à supposer une allocation de pollution positive à la solution optimale alors qu'une élimination complète serait possible. L'exemple de l'amiante montre qu'il existe des situations où la pollution-zéro est préférable à un niveau positif. Ce chapitre montre sous quelles conditions ce postulat est vrai. Le troisième travail se concentre sur la notion de services environnementaux. Ce chapitre montre que ceux-ci sont parfaitement substituables aux autorisations de polluer. L'Etat peut donc sélectionner le prix des services environnementaux et il devient possible d'établir une allocation optimale des ressources même en présence de compétition imparfaite. Enfin, le dernier chapitre détaille une supposée fusion entre un pollueur et son fournisseur de biens et services environnementaux. Il montre les répercussions de la fusion sur une firme non-intégrée et amène une discussion sur la différence entre réduction de la pollution en procédé-intégré ou en bout-de-chaîne. / This research focuses on the modeling of ecoindustries and the properties commonly assigned to them. Precisely, highlighting ecoindustries requires the making of some assumptions with nontrivial consequences. This work uncovers these consequences as well as the adequacy of some of them.The first chapter considers polluting ecoindustries, although economic analysis on the subject generally assumes that environmental goods and services suppress the pollutants. This chapter shows mechanisms through which the market distributes economic activity to ecoindustries according to their technology.The second chapter investigates the limits of supposing a positive pollution allocation at the optimal solution although complete suppression is feasible. The example of asbestos shows that there are situations in which zero-pollution is preferred to a positive amount. The chapter shows the conditions under which this hypothesis is true.The third work focuses on the concept of environmental services. This chapter shows that environmental services and pollution allowances are perfect substitutes, then the government can decide on their prices so that it is possible to decentralize a first-best allocation of resources even in the presence of imperfect competition.Finally, the last chapter details a fictional fusion between a polluter and its environmental goods and services supplier. It shows the consequences of such fusion on an unintegrated firm and opens a discussion on the difference between process-integrated and end-of-pipepollution abatement.

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