No description available.

This dissertation explores technical regulations (sanitary and phytosanitary (SPS) measures, technical barriers to trade, and geographical indications) in Central American agricultural and food trade. In the first part, a framework to systematically evaluate the broad issues for developing countries is presented. Evaluation of the issues for Central America is based on interviews with about 100 persons in the region and in the United States (US), and on secondary sources. The topic is of significance in Central America, especially when related to SPS measures. The World Trade Organization (WTO) Agreements have had relatively little direct impact in improving Central America's response to technical regulations, while homologous Central American regional institutions may have been more successful, with indirect support from the WTO and the US, in reducing the incidence of illegitimate regulations in intra-regional trade. Central America may implement illegitimate barriers more against others in the region than against the US. Although the Central America Free Trade Agreement (CAFTA) may support Central America's capacity to meet more stringent technical regulations, the improvement may not be sufficiently perceptible. The potential for Central American greenhouse tomato exports to the US is analytically evaluated in the second part. These tomatoes may be admitted as the ban based on the risk of introduction of the Mediterranean fruit fly is partially lifted, due in part on discussions in the CAFTA negotiations. Mature green, vine-ripe and greenhouse tomatoes are heterogeneous in demand, and vine-ripe tomatoes are but greenhouse tomatoes are not heterogeneous by origin. A static partial equilibrium model is constructed for the US tomato market, where demand is based on multi-stage budgeting and supply is a function of own tomato price. When the Central American greenhouse excess supply function is introduced to the model, the region exports to the US, the aggregate greenhouse quantity increases, and its prices decrease. As greenhouse preference increases, greenhouse quantity and prices also increase. Changes are perceptible but small in the mature green and vine-ripe markets in the expected direction. Access by Central America is particularly beneficial when US consumer preferences shift further toward greenhouse over other tomatoes. / Ph. D.

This thesis examines the effects on demand, supply, imports, and prices of partial easing of sanitary and phytosanitary (SPS) barriers to trade in the U.S. market in the case of Mexican avocados. The SPS Agreement plays a role in the avocado market studied here through its implications for negotiations between countries that have not utilized the formal channels of the WTO for resolving disputes. A quarantine in place from 1914 until very recently banned entry of Mexican avocados into the U.S. market on grounds of risk of pest infestation. Since the early 1970s this quarantine has been a cause of dispute between the Mexican and U.S. governments, resulting in elaborate evaluations of possible pest risks and risk mitigation procedures that might be carried out. However, after the initiation of negotiations for the North American Free Trade Agreement (NAFTA) in 1991, the import ban was partially eased in 1995 allowing Mexico access to the Northeastern part of the U.S. during four winter months. After three years of successfully exporting without any pest outbreaks, Mexico requested increased access to an additional part of the U.S. market, which it was granted in 2001. This study develops a partial equilibrium trade model to investigate the effects that this increased access will have on the avocados markets. Hypothesized further increases in access are described, and their potential effects are evaluated as well. / Master of Science

Municipal solid waste landfills are convenient means of disposing of society's waste; once closed, they become a liability to the community due to attributes which contribute to soil and water contamination. Regulations state that adequate vegetation be used to maintain the integrity of the soil trash cover. Alternatives to leaving a landfill derelict include establishing meadow-type communities that enrich floristic diversity while providing adequate cover to protect the soil cap over the trash. In 1993, an experimental study was conducted at the Roanoke Regional Landfill where a mixture of native wildflowers and grasses and the standard revegetation mixture were sown on plots on varying aspects at the landfill. In 1993, the plots sown with the native mixture had a higher average species richness than the plots planted with the native mixture. Plots with the standard revegetation mixture had higher cover than plots planted with the native mixture. In 1993 and 1994, an observational study was conducted at the Chancellorsville landfill in Spotsylvania county. Wildflowers had been seeded on part of the landfill in 1992. It was observed that the wildflower mixture decreased in species richness. The areas revegetated with the standard revegetation mixture had high richness due to the presence of invasive plants. Average cover over time was higher in areas planted with the standard revegetation mixture. Without regulations quantifying standards for aboveground cover, other methods should be implemented to determine to what extent revegetation mixtures are maintaining the integrity of a soil cap. / Master of Science

The possibility of acetone shock loadings to phenol acclimated systems resulting in sequential substrate utilization and increased effluent phenol concentrations was evaluated. Phenol acclimated batch and continuous-flow systems, developed with seed from a municipal wastewater treatment plant, were shock loaded with acetone, bacto-peptone, and domestic primary effluent. Phenol and acetone utilization rates were then monitored using direct injection gas-liquid chromatography. The results of the investigation indicated that, under the described experimental conditions, qualitative shock loading of phenol acclimated/utilizing cultures had no significant effect on effluent phenol concentrations. Variations of system pH, however, were found to have extreme effects. / Master of Science

This thesis estimates the impact of non-tariff measures (NTMs) notified by the importing countries on agricultural trade. The non-tariff measures constitute the technical measures notified under the SPS and TBT agreements and the non-technical measures to trade. Two approaches are used; the inventory approach and the econometric approach which makes use of the gravity model. The inventory results suggest that African countries face more restrictions on their exports than what they impose on their imports. Also, Uganda, Senegal and Mali are among the top twenty most affected importers. The empirical results suggest that the impact of the overall group on non-tariff measures is ambiguous but when measures are disaggregated into technical and non-technical measures, the results show that the technical measures promote agricultural trade and that the non-technical measures restrict trade. Also, imports of industrialized nations from fellow industrialized nations are promoted by the technical measures but are restricted by non-technical measures, while those from non-industrialized countries are affected negatively by both technical and non-technical measures. Out of the five regions considered, Africa faces the largest negative impact by both technical and non-technical measures. / Master of Science

No description available.

No description available.

No description available.

by Tong Suk Wah. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 196-206). / Abstract --- p.i / Acknowledgments --- p.iv / Table of Contents --- p.v / List of Abbreviations --- p.ix / List of Tables --- p.xi / List of Figures --- p.xv / Chapter 1 --- Introduction / Chapter 1.1 --- Landfilling in Hong Kong --- p.1 / Chapter 1.2 --- Generation of Landfill Leachate --- p.3 / Chapter 1.3 --- Composition of Landfill Leachate --- p.6 / Chapter 1.4 --- Toxicity of Landfill Leachate --- p.12 / Chapter 1.5 --- Treatment of Landfill Leachate --- p.15 / Chapter 1.5.1 --- Physico-chemical treatment --- p.16 / Chapter 1.5.1.1 --- Coagulation/Flocculation/Precipitation --- p.16 / Chapter 1.5.1.2 --- Oxidation --- p.18 / Chapter 1.5.1.3 --- Activated carbon adsorption --- p.19 / Chapter 1.5.1.4 --- Ammonia stripping --- p.20 / Chapter 1.5.1.5 --- Reverse osmosis --- p.21 / Chapter 1.5.2 --- Biological treatment --- p.22 / Chapter 1.5.2.1 --- Aerobic treatment --- p.22 / Chapter 1.5.2.1.1 --- Activated sludge system --- p.23 / Chapter 1.5.2.1.2 --- Aeration lagoon --- p.25 / Chapter 1.5.2.1.3 --- Sequencing batch reactor --- p.26 / Chapter 1.5.2.1.4 --- Trickling filter --- p.27 / Chapter 1.5.2.1.5 --- Rotating biological contactor --- p.27 / Chapter 1.5.2.2 --- Anaerobic treatment --- p.29 / Chapter 1.5.3 --- Co-treatment with municipal wastewater --- p.32 / Chapter 1.5.4 --- Recirculation --- p.33 / Chapter 1.5.5 --- Irrigation --- p.34 / Chapter 1.6 --- Aims of the Thesis --- p.35 / Chapter 2 --- Characterization of Landfill Leachate / Chapter 2.1 --- Introduction --- p.37 / Chapter 2.2 --- Materials and Methods / Chapter 2.2.1 --- Description of landfill sites --- p.39 / Chapter 2.2.2 --- Leachate collection --- p.40 / Chapter 2.2.3 --- Chemical analysis --- p.40 / Chapter 2.2.4 --- Biological analysis --- p.41 / Chapter 2.2.5 --- Statistical analysis --- p.42 / Chapter 2.3 --- Results and Discussion / Chapter 2.3.1 --- Chemical properties of leachate --- p.43 / Chapter 2.3.2 --- Temporal variation of leachate quality --- p.61 / Chapter 2.3.3 --- Correlation of leachate quality and rainfall --- p.65 / Chapter 2.3.4 --- Biological composition of leachate --- p.86 / Chapter 2.4 --- Conclusions --- p.88 / Chapter 3 --- Toxicological Analysis of Landfill Leachate / Chapter 3.1 --- Introduction --- p.92 / Chapter 3.2 --- Materials and Methods / Chapter 3.2.1 --- Leachate collection --- p.93 / Chapter 3.2.2 --- Chemical analysis --- p.94 / Chapter 3.2.3 --- Biological toxicity testing --- p.94 / Chapter 3.2.3.1 --- Microtox test --- p.95 / Chapter 3.2.3.2 --- Algal bioassay、 --- p.95 / Chapter 3.2.3.3 --- Crustacean bioassay --- p.96 / Chapter 3.2.3.4 --- Fish bioassay --- p.98 / Chapter 3.3 --- Results and Discussion / Chapter 3.3.1 --- Chemical properties of leachate --- p.99 / Chapter 3.3.2 --- Microtox test --- p.105 / Chapter 3.3.3 --- Algal bioassay --- p.108 / Chapter 3.3.4 --- Crustacean bioassay --- p.115 / Chapter 3.3.5 --- Fish bioassay --- p.115 / Chapter 3.4 --- Conclusions --- p.120 / Chapter 4 --- Nitrification of Landfill Leachate / Chapter 4.1 --- Introduction --- p.124 / Chapter 4.2 --- Materials and Methods / Chapter 4.2.1 --- Collection and analysis of leachate --- p.127 / Chapter 4.2.2 --- Set-up of nitrification system --- p.128 / Chapter 4.2.3 --- Experiment 1: Effect of additional phosphate on the rate of nitrification --- p.130 / Chapter 4.2.4 --- Experiment 2: Effect of HRT on the rate of nitrification --- p.130 / Chapter 4.2.5 --- Experiment 3: Effect of additional organic carbon on the rate of nitrification --- p.131 / Chapter 4.2.6 --- Statistical analysis --- p.131 / Chapter 4.3 --- Results and Discussion / Chapter 4.3.1 --- Chemical properties of landfill leachate --- p.132 / Chapter 4.3.2 --- Experiment 1: Effect of additional phosphate on the rate of nitrification --- p.132 / Chapter 4.3.3 --- Experiment 2: Effect of HRT on the rate of nitrification --- p.144 / Chapter 4.3.4 --- Experiment 3: Effect of additional organic carbon on the rate of nitrification --- p.154 / Chapter 4.3.5 --- Inhibition of free ammonia and nitrous acid --- p.162 / Chapter 4.3.6 --- Fate of ammonia --- p.166 / Chapter 4.4 --- Conclusions --- p.170 / Chapter 5 --- Denitrification of Nitrified Leachate / Chapter 5.1 --- Introduction --- p.172 / Chapter 5.2 --- Materials and Methods / Chapter 5.2.1 --- Collection and analysis of landfill leachate --- p.175 / Chapter 5.2.2 --- Set-up of treatment system --- p.176 / Chapter 5.2.3 --- Statistical analysis --- p.178 / Chapter 5.3 --- Results and Discussion / Chapter 5.3.1 --- Performance of nitrification system --- p.178 / Chapter 5.3.2 --- Performance of denitrification system --- p.181 / Chapter 5.3.3 --- Improvement of treatment efficiency --- p.187 / Chapter 5.4 --- Conclusions --- p.190 / Chapter 6 --- General Conclusions --- p.192 / References --- p.196 / Appendices / "Appendix 1 Medium for enumeration of heterotrophic bacteria, fungi, carbohydrate-utilizing bacteria, protein-utilizing bacteria and lipid-utilizing bacteria" --- p.207 / Appendix 2 Preparation of Bristol's medium --- p.210 / Appendix 3 Enumeration of ammonia oxidizers by Most Probable Number Method --- p.211 / Appendix 4 Enumeration of nitrite oxidizers by Most Probable Number Method --- p.214