Tsang Chin-kan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 165-176). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.v / Table of contents --- p.vi / List of tables --- p.ix / List of figures --- p.x / List of plates --- p.xii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Municipal solid waste generation and disposal --- p.1 / Chapter 1.2 --- Land filling --- p.3 / Chapter 1.3 --- Landfill sturcture --- p.6 / Chapter 1.3.1 --- Landfill envelope --- p.6 / Chapter 1.3.2 --- Landfill lining --- p.6 / Chapter 1.3.3 --- Leach ate collection and removal system --- p.9 / Chapter 1.3.4 --- Gas collection and control system --- p.9 / Chapter 1.3.5 --- Final cover system --- p.9 / Chapter 1.4 --- Landfill leach ate generation and characterization --- p.11 / Chapter 1.4.1 --- Landfill stabilization and leachate characteristics --- p.13 / Chapter 1.4.1.1 --- Aerobic phase / Chapter 1.4.1.2 --- Acetogenic phase / Chapter 1.4.1.3 --- Methanogenic phase / Chapter 1.4.2 --- Leachtate characteristic and landfill age --- p.15 / Chapter 1.5 --- Toxicity of landfill leachate --- p.17 / Chapter 1.6 --- Leachate treatment --- p.18 / Chapter 1.6.1 --- Land disposal --- p.19 / Chapter 1.6.1.1 --- Leachate recirculation / Chapter 1.6.1.2 --- Leachate irrigation / Chapter 1.7 --- Landfills in Hong Kong --- p.25 / Chapter 1.7.1 --- Landfill leachate generation in Hong Kong --- p.27 / Chapter 1.8 --- Selection of sampling sites --- p.29 / Chapter 1.9 --- Knowledge gaps --- p.33 / Chapter 1.10 --- Aims of thesis --- p.34 / Chapter 1.11 --- Project outlines --- p.34 / Chapter Chapter 2 --- Species selection for leachate irrigation / Chapter 2.1 --- Introduction --- p.35 / Chapter 2.2 --- Materials and Methods --- p.36 / Chapter 2.2.1 --- Leachate collection --- p.38 / Chapter 2.2.2 --- Chemical analysis of leachate --- p.38 / Chapter 2.2.3 --- Greenhouse pot experiment --- p.40 / Chapter 2.2.4 --- Plant harvesting and post harvest analysis --- p.43 / Chapter 2.2.4.1 --- Foliar N and P / Chapter 2.2.5 --- Statistical analysis and test endpoints --- p.43 / Chapter 2.3 --- Results and Discussion --- p.43 / Chapter 2.3.1 --- Leachate composition --- p.43 / Chapter 2.3.2 --- Plant growth performance --- p.45 / Chapter 2.3.3 --- Biomass production --- p.54 / Chapter 2.3.4 --- Chlorophyll fluorescence --- p.54 / Chapter 2.3.5 --- Tissue nutrient contents --- p.58 / Chapter 2.3.5.1 --- Foliar N / Chapter 2.3.5.2 --- Foliar P / Chapter 2.3.6 --- Effects on N-fixation --- p.60 / Chapter 2.3.7 --- Factors affecting N-fixation regarding leachate irrigation --- p.63 / Chapter 2.3.7.1 --- Soil mineral N content / Chapter 2.3.7.2 --- Soil acidity / Chapter 2.3.7.3 --- Salinity / Chapter 2.3.7.4 --- Soil aeration / Chapter 2.3.8 --- Species selection --- p.67 / Chapter 2.4 --- Conclusions --- p.68 / Chapter Chapter 3 --- Plant growth response of leachate irrigation on phosphorus-amended soil / Chapter 3.1 --- Introduction --- p.71 / Chapter 3.2 --- Materials and Methods --- p.73 / Chapter 3.2.1 --- Leachate sampling and analysis --- p.73 / Chapter 3.2.2 --- Experimental setup --- p.73 / Chapter 3.2.3 --- Plant and soil sampling --- p.74 / Chapter 3.2.3.1 --- Soil pH and electrical conductivity (EC) / Chapter 3.2.3.2 --- Soil N / Chapter 3.2.3.3 --- Soil P / Chapter 3.2.4 --- Statistical analysis --- p.76 / Chapter 3.3 --- Results and Discussion --- p.76 / Chapter 3.3.1 --- Leachate composition --- p.76 / Chapter 3.3.2 --- Plant growth performance --- p.78 / Chapter 3.3.3 --- Biomass --- p.83 / Chapter 3.3.4 --- Tissue contents --- p.87 / Chapter 3.3.4.1 --- Foliar N / Chapter 3.3.4.2 --- Foliar P / Chapter 3.3.5 --- Soil --- p.91 / Chapter 3.3.5.1 --- pH and electrical conductivity / Chapter 3.3.5.2 --- Soil N / Chapter 3.3.5.3 --- Soil P / Chapter 3.3.5.4 --- Addition of lime and gypsum / Chapter 3.4 --- Conclusions --- p.102 / Chapter Chapter 4 --- Responses in plant growth and soil biology to prolonged landfill leachate irrigation / Chapter 4.1 --- Introduction --- p.105 / Chapter 4.2 --- Materials and Methods --- p.107 / Chapter 4.2.1 --- Leachate sample and collection --- p.107 / Chapter 4.2.2 --- Soil column design --- p.107 / Chapter 4.2.3 --- Plant establishment --- p.107 / Chapter 4.2.4 --- Leachate application --- p.108 / Chapter 4.2.5 --- Soil and plant analysis --- p.108 / Chapter 4.2.5.1 --- Soil texture / Chapter 4.2.5.2 --- SOM / Chapter 4.2.5.3 --- Soil chloride content / Chapter 4.2.6 --- Soil and plant analysis --- p.110 / Chapter 4.2.6.1 --- Dehydrogenase / Chapter 4.2.6.2 --- Phosphatase / Chapter 4.2.6.3 --- Urease / Chapter 4.2.6.4 --- Nitrification / Chapter 4.2.7 --- Percolate --- p.112 / Chapter 4.2.8 --- Statistical analysis --- p.112 / Chapter 4.3 --- Results and Discussion --- p.113 / Chapter 4.3.1 --- Leachate --- p.113 / Chapter 4.3.2 --- Plants --- p.113 / Chapter 4.3.2.1 --- Plant growth / Chapter 4.3.2.2 --- Tissue contents / Chapter 4.3.3 --- Soil --- p.121 / Chapter 4.3.3.1 --- Soil texture / Chapter 4.3.3.2 --- pH and EC / Chapter 4.3.3.3 --- Soil N / Chapter 4.3.3.4 --- Soil P / Chapter 4.3.3.5 --- Soil C1' / Chapter 4.3.3.6 --- SOM / Chapter 4.3.4 --- Soil enzyme and nitrification --- p.132 / Chapter 4.3.4.1 --- Dehydrogenase / Chapter 4.3.4.2 --- Phosphatase / Chapter 4.3.4.3 --- Urease / Chapter 4.3.4.4 --- Nitrification / Chapter 4.3.4.5 --- Correlation analysis / Chapter 4.3.5 --- Percolate --- p.144 / Chapter 4.3.6 --- N balance --- p.150 / Chapter 4.3.7 --- N saturation --- p.153 / Chapter 4.4 --- Conclusions --- p.156 / Chapter Chapter 5 --- General conclusions / Chapter 5.1 --- Summary of findings --- p.158 / Chapter 5.2 --- General considerations regarding leachate irrigation --- p.161 / Chapter 5.3 --- Research prospects --- p.162 / References --- p.165

Wong Shiu Kai Raymond. / Thesis submitted in: July 2003. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 147-157). / Abstracts in English and Chinese. / ABSTRACT --- p.I / ACKNOWLEDGEMENTS --- p.V / TABLE OF CONTENTS --- p.VI / LIST OF ABBREVIATIONS --- p.IX / LIST OF TABLES --- p.X / LIST OF FIGURES --- p.XII / LIST OF PLATES --- p.XVII / Chapter 1. --- INTRODUCTION / Chapter 1.1 --- Landfilling of Solid Wastes --- p.1 / Chapter 1.2 --- Landfilling in Hong Kong --- p.3 / Chapter 1.3 --- Problems of Landfill Leachate --- p.5 / Chapter 1.4 --- Generation of Landfill Leachate --- p.6 / Chapter 1.5 --- Chemical Properties of Landfill Leachate --- p.9 / Chapter 1.6 --- Ecotoxicity of Landfill Leachate --- p.16 / Chapter 1.7 --- Identification of Leachate Toxicity / Chapter 1.7.1 --- Problem of identification of toxicants in landfill leachate --- p.21 / Chapter 1.7.2 --- Toxicity Identification Evaluation --- p.22 / Chapter 1.8 --- Aims of Thesis --- p.27 / Chapter 2. --- CHEMICAL CHARACTERIZATION OF LANDFILL LEACHATE / Chapter 2.1 --- Introduction --- p.30 / Chapter 2.2 --- Materials and Methods / Chapter 2.2.1 --- Site description --- p.33 / Chapter 2.2.2 --- Leachate collection --- p.38 / Chapter 2.2.3 --- Chemical analysis --- p.38 / Chapter 2.2.4 --- Statistical analysis --- p.41 / Chapter 2.3 --- Results and Discussion / Chapter 2.3.1 --- Chemical properties of landfill leachates --- p.41 / Chapter 2.3.2 --- Variation of chemical properties with different ages --- p.53 / Chapter 2.3.3 --- Variation of chemical properties with different season --- p.56 / Chapter 2.3.4 --- Principal Component Analysis --- p.85 / Chapter 2.4 --- Conclusions --- p.91 / Chapter 3. --- ECOTOXICOLOGICAL CHARACTERIZATION OF LANDFILL LEACHATE / Chapter 3.1 --- Introduction --- p.93 / Chapter 3.2 --- Materials and Methods / Chapter 3.2.1 --- Site description --- p.95 / Chapter 3.2.2 --- Leachate collection --- p.95 / Chapter 3.2.3 --- Toxicity tests --- p.95 / Chapter 3.2.3.1 --- Microtox® test --- p.96 / Chapter 3.2.3.2 --- Protozoan bioassay --- p.97 / Chapter 3.2.3.3 --- Algal bioassay --- p.99 / Chapter 3.2.3.4 --- Crustacean bioassays --- p.102 / Chapter 3.2.3.5 --- Statistical analysis --- p.104 / Chapter 3.3 --- Results and Discussion / Chapter 3.3.1 --- Leachate toxicity --- p.105 / Chapter 3.3.2 --- Sensitivity of tested organisms --- p.110 / Chapter 3.3.3 --- Principal Component Analysis --- p.113 / Chapter 3.3.4 --- Correlation with chemical properties --- p.116 / Chapter 3.4 --- Conclusions --- p.120 / Chapter 4. --- TOXICITY IDENTIFICATION EVALUATION OF MAJOR TOXICANTS IN LANDFILL LEACHATE / Chapter 4.1 --- Introduction --- p.122 / Chapter 4.2 --- Materials and Methods / Chapter 4.2.1 --- Site description --- p.124 / Chapter 4.2.2 --- Toxicity bioassays --- p.124 / Chapter 4.2.3 --- Phase I Toxicity characterization --- p.125 / Chapter 4.2.4 --- Phase II Toxicity identification and multiple manipulations --- p.126 / Chapter 4.2.5 --- Phase III Toxicity confirmation --- p.128 / Chapter 4.3 --- Results and Discussion / Chapter 4.3.1 --- Chemical properties of collected sample --- p.129 / Chapter 4.3.2 --- Phase I results --- p.130 / Chapter 4.3.3 --- Phase II results --- p.132 / Chapter 4.3.4 --- Phase III results --- p.138 / Chapter 4.3.5 --- Use of TIE in leachate monitoring --- p.139 / Chapter 4.4 --- Conclusions --- p.140 / Chapter 5. --- OVERALL CONCLUSIONS --- p.142 / REFERENCES --- p.147

Les Evénements Océaniques Anoxiques (OAE) sont des événements extrêmes qui se sont pro- duits majoritairement durant le Crétacé et qui sont caractérisés par un enfouissement massif et brutal de carbone organique. Ces événements ont été très étudiés durant ces 40 dernières années mais aucun consensus n’a été atteint quand aux processus à l’origine de leur déclenchement. Pour tenter de répondre aux questions encore en suspens, nous avons réalisé une étude géochimique approfondie (éléments majeurs et traces, compositions isotopiques en Nd et Hf) des différentes fractions (détritiques et authigènes) de sédiments marins déposés lors de l’événement océanique anoxique associé à la limite Cénomanien-Turonien (OAE2, 93.5Ma). Les deux sections étudiées représentent différents environnements de dépôt : un environnement peu profond et proche des sources continentales (Taghazoute, Maroc) et un environnement marin profond, loin des côtes (DSDP Site 367, Cap-Vert).A l’approche de l’OAE2, les compositions isotopiques du Nd et de l’Hf ne présentent que peu de variations. Ces observations reflètent une absence de changement dans le régime d’érosion continentale en amont des deux sections étudiées. Notre étude diverge du scenario proposant qu’un fort apport de nutriments résultant d’une altération continentale accrue soit à l’origine des OAEs. En revanche, les variations isotopiques (Nd) mesurées dans les fractions authigènes du Site 367, interprétées comme reflétant la composition océanique passée, supportent l’idée d’une contribution magmatique dans l’Océan Atlantique durant l’OAE2. Ces nouveaux résultats sont cohérents avec de précédentes études et confortent le rôle des grandes provinces magmatiques (plateau des Caraïbes) dans l’eutrophisation des océans qui précède les événements anoxiques.En outre, l’étude combinée des terres rares (REE) et des compositions isotopiques (Nd) de fractions authigènes obtenues par extraction chimique (leaching) démontre l’incorporation de matériel détritique dans ces fractions en milieu peu profond. Ces nouvelles observations questionnent l’idée que toute fraction authigène enregistre une composition chimique océanique pure. Enfin, l’étude complète des concentrations en éléments traces de ces mêmes fractions souligne le rôle important de la lithologie des sédiments sur la composition des leachates. Cette étude questionne également l’utilisation de certaines méthodes de leaching qui semblent favoriser l’extraction de phases détritiques externes lorsque les sédiments sont soumis à des étapes de leaching répétées. / Oceanic Anoxic Events (OAE) are brief and extreme events that mostly occurred during the Cretaceous and are defined by the burial of massive amounts of organic carbon. These events have been intensely investigated in the last 40 years but the mechanism that triggered OAEs remains problematic. In order to better constrain what causes these events, we realised a complete geochemical study (major and trace elements, isotopic compositions of Nf and Hf) of various sedimentary fractions (detrital and authigenic) for marine sediments associated with the Cenomanian-Turonian boundary event or OAE2 (93.5 Ma). We focused our study on two marine sections that represent different depositional settings : a shallow marine setting, close to the continental shelf (Taghazoute, Morocco) and a abyssal marine section (DSDP Site 367, Cape-Verde), far from the African shelf.The remarkable stability of the Nd-Hf decoupling in both sections indicates no obvious change of continental weathering approaching OAE2. Our conclusions diverge from the hypothesis that proposes an higher nutrient input through an enhanced continental weathering as a triggering mechanism of OAEs. However, Nd isotopic compositions of authigenic fractions measured at Site 367, interpreted as past oceanic composition, exhibit a positive isotopic excursion and indicate a magmatic contribution in the deep Atlantic Ocean during OAE2. These new data are consistent with previous isotopic studies and support the role of Large Igneous Province (in our case, the Caribbean Plateau) as nutrient provider and triggering mechanism of anoxic events.The combined study of rare earth elements (REE) and Nd isotopic compositions of authigenic fractions recovered by leaching demonstrates the incorporation of detrital material in authigenic fractions in shallow marine settings. These new results challenge the traditional belief that authigenic material always records an untouched seawater composition. Finally, the extensive study of trace element concentrations of these same fractions demonstrated the strong impact of sample lithology on their trace element content. Our study also questions the relevance of sequential leaching methods that facilitate external contamination when sediments are submitted to repeated leaching steps.

Cheng Chung-yin. / Thesis submitted in: December 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 185-195). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.vi / Table of contents --- p.viii / List of tables --- p.xi / List of figures --- p.xii / List of plates --- p.xiv / Plant species used in the experiments --- p.xv / Chapter 1 Introduction / Chapter 1.1 --- Soil wastes as an environmental challenge --- p.1 / Chapter 1.2 --- Landfilling --- p.1 / Chapter 1.2.1 --- Waste degradation --- p.4 / Chapter 1.2.2 --- Control of degradation by-products --- p.6 / Chapter 1.3 --- Landfill leach ate --- p.8 / Chapter 1.3.1 --- Generation and control of landfill leachate --- p.8 / Chapter 1.3.2 --- Leachate characterization --- p.10 / Chapter 1.3.3 --- Leachate from local landfills --- p.15 / Chapter 1.3.4 --- Leachate treatment --- p.15 / Chapter 1.4 --- Leachate irrigation --- p.16 / Chapter 1.4.1 --- Common practices of wastewater irrigation --- p.17 / Chapter 1.4.1.1 --- Spray irrigation / Chapter 1.4.1.2 --- Rapid infiltration / Chapter 1.4.1.3 --- Overland flow / Chapter 1.4.2 --- Effects of leachate irrigation --- p.19 / Chapter 1.4.2.1 --- Effect of leachate irrigation on soil percolate / Chapter 1.4.2.2 --- Effect of leachate irrigation on soil / Chapter 1.4.2.3 --- Effect of leachate irrigation on plants / Chapter 1.5 --- Landfilling in Hong Kong --- p.24 / Chapter 1.5.1 --- Climate --- p.24 / Chapter 1.5.2 --- Geography and economy --- p.25 / Chapter 1.5.3 --- Waste composition --- p.25 / Chapter 1.5.4 --- Leachate sampling sites --- p.27 / Chapter 1.6 --- Objectives of this study --- p.30 / Chapter 1.6.1 --- Knowledge gaps --- p.30 / Chapter 1.6.2 --- Project outline --- p.33 / Chapter Chapter 2 --- Phytotoxicity evaluation of landfill leachate using seed germination tests / Chapter 2.1 --- Introduction --- p.34 / Chapter 2.1.1 --- Tests involving the use of germinating seeds --- p.34 / Chapter 2.1.2 --- Importance of germination to plants --- p.34 / Chapter 2.1.3 --- Advantages of germination tests --- p.35 / Chapter 2.1.4 --- Limitations of using germination as an endpoint --- p.35 / Chapter 2.1.5 --- Methods of germination test --- p.36 / Chapter 2.1.5.1 --- Test design / Chapter 2.1.5.2 --- Plant species / Chapter 2.1.5.3 --- Measurement endpoints / Chapter 2.1.5.4 --- Statistical analysis and test endpoints / Chapter 2.2 --- Objectives of study --- p.41 / Chapter 2.3 --- Materials and methods --- p.42 / Chapter 2.3.1 --- Sample collection --- p.42 / Chapter 2.3.2 --- Chemical analysis --- p.42 / Chapter 2.3.3 --- Statistical analysis --- p.43 / Chapter 2.3.4 --- Phytotoxicity assay --- p.43 / Chapter 2.4 --- Results and discussion --- p.44 / Chapter 2.4.1 --- Leachate characterization --- p.44 / Chapter 2.4.1.1 --- Comparison among landfill sites / Chapter 2.4.2 --- Phytotoxicity assay --- p.51 / Chapter 2.4.2.1 --- Dose response relationships / Chapter 2.4.2.2 --- Implication of hormetic-like response on the selection of statistical model / Chapter 2.4.2.3 --- Phytotoxicity of leachate samples / Chapter 2.4.2.4 --- Comparison between species / Chapter 2.5 --- Conclusions --- p.65 / Chapter Chapter 3 --- Leachate irrigation: Effects on plant performance and soil properties / Chapter 3.1 --- Introduction --- p.67 / Chapter 3.2 --- Materials and methods --- p.70 / Chapter 3.2.1 --- Leachate sampling and analysis --- p.70 / Chapter 3.2.2 --- Leachate irrigation experiment --- p.71 / Chapter 3.2.3 --- Soil and plant analysis --- p.73 / Chapter 3.2.3.1 --- Soil sampling and preparation / Chapter 3.2.3.2 --- Soil texture / Chapter 3.2.3.3 --- pH and electrical conductivity / Chapter 3.2.3.4 --- Organic carbon / Chapter 3.2.3.5 --- Nitrogen / Chapter 3.2.3.6 --- Phosphorus / Chapter 3.2.3.7 --- Chloride / Chapter 3.2.3.8 --- Metals / Chapter 3.2.3.9 --- Foliage analysis / Chapter 3.3 --- Results and discussion --- p.75 / Chapter 3.3.1 --- Leachate --- p.75 / Chapter 3.3.1.1 --- Chemical properties / Chapter 3.3.1.2 --- Phytotoxicity / Chapter 3.3.2 --- Plant responses --- p.79 / Chapter 3.3.2.1 --- Growth / Chapter 3.3.2.2 --- Plant survival and health / Chapter 3.3.2.3 --- Tissue contents / Chapter 3.3.2.4 --- Incorporating the results of germination tests in leachate irrigation practice / Chapter 3.3.3 --- Soil --- p.101 / Chapter 3.3.3.1 --- Initial properties / Chapter 3.3.3.2 --- Soil reaction (pH) / Chapter 3.3.3.3 --- Nitrogen / Chapter 3.3.3.4 --- Phosphorus / Chapter 3.3.3.5 --- Conductivity / Chapter 3.3.3.6 --- Chloride / Chapter 3.3.3.7 --- Metals / Chapter 3.4 --- Conclusions --- p.119 / Chapter Chapter 4 --- Fate and distribution of N after soil application of landfill leachate / Chapter 4.1 --- Introduction --- p.121 / Chapter 4.1.1 --- The needs of external N supply in ecological restoration --- p.121 / Chapter 4.1.2 --- Objectives of study --- p.122 / Chapter 4.2 --- Materials and methods --- p.123 / Chapter 4.2.1 --- Leachate --- p.124 / Chapter 4.2.2 --- Soil column --- p.124 / Chapter 4.2.3 --- Plant selection and establishment --- p.127 / Chapter 4.2.3 --- Leachate application --- p.129 / Chapter 4.2.4 --- Post irrigation harvesting and analysis --- p.130 / Chapter 4.3 --- Results and discussion --- p.130 / Chapter 4.3.1 --- Leachate --- p.130 / Chapter 4.3.2 --- Plants --- p.132 / Chapter 4.3.2.1 --- Growth / Chapter 4.3.2.2 --- Tissue N contents / Chapter 4.3.3 --- Soil and soil percolate --- p.139 / Chapter 4.3.3.1 --- Percolate volume and soil moisture / Chapter 4.3.3.2 --- pH / Chapter 4.3.3.3 --- Electrical conductivity / Chapter 4.3.3.4 --- Nitrate / Chapter 4.3.3.5 --- Ammonium / Chapter 4.3.4 --- N balance of the soil-plant system --- p.160 / Chapter 4.3.4.1 --- Change in the N capital after leachate irrigation / Chapter 4.3.4.2 --- Leaching loss / Chapter 4.3.4.3 --- Unaccountable N loss / Chapter 4.4 --- Conclusions --- p.174 / Chapter Chapter 5 --- General conclusion / Chapter 5.1 --- Summary of findings --- p.176 / Chapter 5.2 --- Ecological consequence of increased and excess N deposition --- p.179 / Chapter 5.3 --- Research prospects --- p.182 / References --- p.185

CAPES / A produção de resíduos sólidos urbanos (RSU) aumenta a cada dia em razão da associação de uma série de fatores, tais como crescimento da população, aumento do poder aquisitivo, facilidade de acesso aos bens de consumo, etc. Em consequência, o gerenciamento e a disposição final tornaram-se um grande problema a ser encarado onde, atualmente, um dos principais meios de destinação final dos RSU é o aterro sanitário. Otimizar sua vida útil devido à ausência de terrenos adequados para este fim, principalmente em grandes centros urbanos, e exigências mais rígidas de órgãos controladores e reguladores, tornou-se um dos principais focos dos gestores tanto municipais quanto estaduais. Uma das formas de melhorar o aproveitamento das áreas de disposição de RSU é o aumento da altura do aterro, porém, se não for realizado de forma correta pode ocasionar danos significativos para o meio ambiente e para a sociedade. A presença de materiais com propriedades semelhantes às fibras existentes na massa de resíduos sólidos, como plásticos e têxteis, promovem um acréscimo na resistência ao cisalhamento da massa de RSU depositada em aterros, porém, esses materiais vão sofrendo decomposição e alterando suas propriedades e, consequentemente, podendo ocasionar mudanças na resistência ao cisalhamento ao longo do tempo. Desta forma, o presente trabalho tem por objetivo avaliar a influência do lixiviado na resistência à força de tração do plástico mole e como objetivos específicos avaliar a influência largura, distância entre as distância entre as ancoragens e taxa de carregamento, nas trações resultantes; verificar se há variação do pH, demanda química de oxigênio (DQO), alcalinidade, ácidos voláteis, nitrogênio amoniacal e fósforo total presentes no lixiviado, ao longo do tempo e avaliar a estrutura e componentes do plástico mole com e sem imersão no lixiviado. Foram utilizadas sacolas plásticas de supermercado, cortadas em tiras de 0,5 e 1,0 cm de largura, estas ficaram em contato com o lixiviado coletado em um aterro sanitário da região metropolitana de Curitiba-PR, e em seguida foram submetidas aos ensaios de força de tração, a cada quinze dias, variando a distância entre as ancoragens (0 cm, 7 cm e 21 cm) e a taxa de carregamento de ensaio (1 mm.min-1 e 4 mm.min-1). O estudo permitiu verificar que os ensaios realizados com largura de 1 cm resultaram em força de tração superior àquelas realizadas com largura de 0,5 cm. A distância entre as ancoragens e taxa de carregamento de ensaio interferem significativamente nos valores de força de tração obtidos, sendo que ensaios realizados com taxa de carregamento de 4 mm.min-1 resultaram em força de tração superior. Quando se leva em consideração o tempo de contato, não foi possível chegar a uma conclusão definitiva, pois o tempo de contato foi relativamente pequeno. Com a análise de microscopia eletrônica de varredura (MEV) e espectroscopia de energia dispersiva (EDS) foi possível verificar que há deposição de sólidos nas tiras plásticas após imersão no lixiviado e que há deposição de diferentes componentes químicos nas tiras plásticas como o alumínio, por exemplo. / The production of municipal solid waste (MSW) increases every day because of the association of a number of factors such as population growth, increased purchasing power, facility of access to consumer goods, etc. Consequently, the management and disposal have become a major problem to be faced where currently one of the main means of disposal of MSW is the landfill. Optimize its useful life due to ausence of suitable land for this purpose, especially in large urban centers, exigencies stricter controllers and regulators; it has become a major focus of both municipal and state managers. One way to improve the use of MSW disposal sites is increasing embankment height, but if not done properly can cause significant damage to the environment and society. The presence of materials with similar properties to existing fibers in the mass of solid waste such as plastics and textiles, promote an increase in mass of the shear strength of MSW landfill, but these materials are undergoing decomposition and changing its properties, consequently, may cause changes in shear strength over time. Thus, this study aims to evaluate the influence of the leachate on the tensile strength of the soft plastic and specific objectives to assess the width, distance between anchors and speed the resulting pulls, check for variation of pH, chemical oxygen demand (COD), alkalinity, volatile fatty acids, ammonia, nitrogen and total phosphorus present in the leachate over time and to assess the structure and the soft plastic components with and without immersion in the leachate. Plastics grocery bags, cut into 0.5 to 1.0 cm wide strips were used. These were in contact with leachate collected in a landfill in the metropolitan region of Curitiba-PR, and then were sub- jected to tensile tests, every fifteen days, varying the distance between the anchors (0 cm, 7cm and 21 cm ) and the test speed (1 mm.min-1 and 4 mm.min-1) .The study showed that the tests performed with a width of 1 cm resulted in those made with superior traction width of 0.5 cm. The distance between the anchors and speed of test interfere significantly in tensile values, and tests performed at a speed of 4 mm.min-1 resulted in superior traction. When taking into account the contact time was not possible to reach a definitive conclusion as contact time was relatively low. With the analysis of scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS) were unable to verify that there is deposition of solids in the plastic strips and that there are different chemical components present in the solid aluminum, for example.

CAPES / A produção de resíduos sólidos urbanos (RSU) aumenta a cada dia em razão da associação de uma série de fatores, tais como crescimento da população, aumento do poder aquisitivo, facilidade de acesso aos bens de consumo, etc. Em consequência, o gerenciamento e a disposição final tornaram-se um grande problema a ser encarado onde, atualmente, um dos principais meios de destinação final dos RSU é o aterro sanitário. Otimizar sua vida útil devido à ausência de terrenos adequados para este fim, principalmente em grandes centros urbanos, e exigências mais rígidas de órgãos controladores e reguladores, tornou-se um dos principais focos dos gestores tanto municipais quanto estaduais. Uma das formas de melhorar o aproveitamento das áreas de disposição de RSU é o aumento da altura do aterro, porém, se não for realizado de forma correta pode ocasionar danos significativos para o meio ambiente e para a sociedade. A presença de materiais com propriedades semelhantes às fibras existentes na massa de resíduos sólidos, como plásticos e têxteis, promovem um acréscimo na resistência ao cisalhamento da massa de RSU depositada em aterros, porém, esses materiais vão sofrendo decomposição e alterando suas propriedades e, consequentemente, podendo ocasionar mudanças na resistência ao cisalhamento ao longo do tempo. Desta forma, o presente trabalho tem por objetivo avaliar a influência do lixiviado na resistência à força de tração do plástico mole e como objetivos específicos avaliar a influência largura, distância entre as distância entre as ancoragens e taxa de carregamento, nas trações resultantes; verificar se há variação do pH, demanda química de oxigênio (DQO), alcalinidade, ácidos voláteis, nitrogênio amoniacal e fósforo total presentes no lixiviado, ao longo do tempo e avaliar a estrutura e componentes do plástico mole com e sem imersão no lixiviado. Foram utilizadas sacolas plásticas de supermercado, cortadas em tiras de 0,5 e 1,0 cm de largura, estas ficaram em contato com o lixiviado coletado em um aterro sanitário da região metropolitana de Curitiba-PR, e em seguida foram submetidas aos ensaios de força de tração, a cada quinze dias, variando a distância entre as ancoragens (0 cm, 7 cm e 21 cm) e a taxa de carregamento de ensaio (1 mm.min-1 e 4 mm.min-1). O estudo permitiu verificar que os ensaios realizados com largura de 1 cm resultaram em força de tração superior àquelas realizadas com largura de 0,5 cm. A distância entre as ancoragens e taxa de carregamento de ensaio interferem significativamente nos valores de força de tração obtidos, sendo que ensaios realizados com taxa de carregamento de 4 mm.min-1 resultaram em força de tração superior. Quando se leva em consideração o tempo de contato, não foi possível chegar a uma conclusão definitiva, pois o tempo de contato foi relativamente pequeno. Com a análise de microscopia eletrônica de varredura (MEV) e espectroscopia de energia dispersiva (EDS) foi possível verificar que há deposição de sólidos nas tiras plásticas após imersão no lixiviado e que há deposição de diferentes componentes químicos nas tiras plásticas como o alumínio, por exemplo. / The production of municipal solid waste (MSW) increases every day because of the association of a number of factors such as population growth, increased purchasing power, facility of access to consumer goods, etc. Consequently, the management and disposal have become a major problem to be faced where currently one of the main means of disposal of MSW is the landfill. Optimize its useful life due to ausence of suitable land for this purpose, especially in large urban centers, exigencies stricter controllers and regulators; it has become a major focus of both municipal and state managers. One way to improve the use of MSW disposal sites is increasing embankment height, but if not done properly can cause significant damage to the environment and society. The presence of materials with similar properties to existing fibers in the mass of solid waste such as plastics and textiles, promote an increase in mass of the shear strength of MSW landfill, but these materials are undergoing decomposition and changing its properties, consequently, may cause changes in shear strength over time. Thus, this study aims to evaluate the influence of the leachate on the tensile strength of the soft plastic and specific objectives to assess the width, distance between anchors and speed the resulting pulls, check for variation of pH, chemical oxygen demand (COD), alkalinity, volatile fatty acids, ammonia, nitrogen and total phosphorus present in the leachate over time and to assess the structure and the soft plastic components with and without immersion in the leachate. Plastics grocery bags, cut into 0.5 to 1.0 cm wide strips were used. These were in contact with leachate collected in a landfill in the metropolitan region of Curitiba-PR, and then were sub- jected to tensile tests, every fifteen days, varying the distance between the anchors (0 cm, 7cm and 21 cm ) and the test speed (1 mm.min-1 and 4 mm.min-1) .The study showed that the tests performed with a width of 1 cm resulted in those made with superior traction width of 0.5 cm. The distance between the anchors and speed of test interfere significantly in tensile values, and tests performed at a speed of 4 mm.min-1 resulted in superior traction. When taking into account the contact time was not possible to reach a definitive conclusion as contact time was relatively low. With the analysis of scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS) were unable to verify that there is deposition of solids in the plastic strips and that there are different chemical components present in the solid aluminum, for example.

Non-oxidative acid leaching of pyrrhotite from Kevitsa’s Ni-concentrate and methods to recover by-products, have been investigated. Selective dissolution of pyrrhotite (Fe1-xS, 0<x<0.25) can enrich the content of the valuable metals, such as Ni and Co, in the final concentrate and will reduce the amount of Fe and S sent to the smelters. The pyrometallurgical smelting of leached concentrate will thus give less formation of smelter by-products in form of slag and SO2. The leaching was studied through an experimental design plan with parameter settings of  38.8% to 57.8% H2SO4 and temperatures from 60 to 100°C. The best results were obtained in experiments carried out at the lower experimental range. Leaching at 60°C with an initial acid concentration of 38.8% H2SO4 was found sufficient to selectively dissolve most of the pyrrhotite; leaving an enriched solid residue. A QEMSCAN analysis of the solid residue confirmed that most of the pyrrhotite had been dissolved and showed that pentlandite was still the main Ni-mineral. Chemical assays showed that more than 95% of the Ni, Co, and Cu remained in the final residue.    The utilized leaching process generates by-products, in the form of large quantities of Fe2+ in solution and gaseous H2S. To recover Fe2+, crystallization of iron(ii) sulfate (FeSO4∙nH2O) from leach solution through cooling have been studied. The crystallized crystals were further dehydrated into the monohydrate (FeSO4∙H2O) through a strong sulfuric acid treatment (80%H2SO4). XRD analysis confirmed that FeSO4∙H2O was the main phase in the final crystals, and a chemical analysis showed a Fe content of about 30%, 1.5% Mg, 0.4% Ca, and 0.2% Ni.    The possibility to leach the concentrate by circulating the acidic solution from the crystallization stage has been tested. The recirculation of the solution showed no negative effects, as the recoveries of elements and chemical assays of the final solid residue were found to be similar to the obtained assay when the concentrate was leached in a fresh solution. / Icke-oxidativ syralakning av magnetkis från Kevitsas Ni-koncentrat har studerats samt metoder för tillvaratagande av biprodukter. Genom en selektiv upplösning av magnetkis (Fe1-xS, 0<x<0.25) kan värdefulla metaller som Ni och Co anrikas i det slutliga koncentratet. Samtidigt som mängden Fe och S som skickas till smältverken minskar, vilket också innebär att mindre biprodukter i form av slagg och SO2 erhålls vid den pyrometallurgiska smältningen av Ni-koncentratet. En experimentell design plan genomfördes för att studera lakningen där syrakoncentrationen varierades från 38.8% till 57.8%H2SO4 och temperatur från 60 till 100°C. Bäst resultat erhölls vid de lägre parameterinställningarna. Lakning vid 60°C med en initial syrakoncentration på 38.8%H2SO4 visade sig vara tillräcklig för att selektivt lösa upp merparten av all magnetkis och lämna kvar en anrikad produkt. Via QUEMSCAN bekräftades att merparten av all magnetkis hade löst upp sig och att huvudsakligt Ni-mineral fortfarande var pentlandit. Kemiska analyser visade att mer än 95% av Ni, Co och Cu stannade kvar i fasta godset.    Den tillämpade lakningsmetoden genererar biprodukter i form av stora mängder Fe2+ i lösning och H2S i gasform. För att tillvarata Fe2+ har kristallisering av laklösning som järn(ii) sulfat (FeSO4∙nH2O) studerats genom kylning. De kristalliserade kristallerna avvattnades till monohydrat, FeSO∙1H2O, genom avvattning i stark svavelsyra (80%H2SO4). XRD bekräftade FeSO∙1H2O som huvudfas i slutliga kristallerna och kemisk analys visade på ca 30%Fe med huvudsakliga orenheter i form av 1.5% Mg, 0.4%Ca och 0.2% Ni.    Möjligheten till att laka i återcirkulerad lösning efter kristallisering har undersökts. Lakning i återcirkulerad lösning visade inga negativa effekter då liknande halter och utbyten erhölls till det fasta godset.

The purpose of this research was to characterize the residual solids produced from hydraulic fracturing operations in the Marcellus Shale region. Four field samples were evaluated: drilling mud, treated sludge from the chemical treatment of process water, solids from the gravity settling of produced water, and sludge solidified prior to disposal in a municipal landfill. Cement kiln dust (CKD), used for solidification, was also considered in this study. All samples were subjected to a variety of laboratory techniques to determine their elemental composition and the potential for the elements to leach from the landfill. Strong acid digestion using a 3:1 combination of nitric acid to hydrochloric acid in a microwave with closed vessels was used to determine overall elemental composition. Leaching experiments were performed with de-ionized water and acetic acid (0.57%, pH 2.88) in an attempt to respectively evaluate the effects of weak and strong fluids that might be encountered by the residuals in landfill environments. Elements were analyzed by means of ICP-MS revealing the increased tendency for alkali metals, alkaline earth metals and halogens to leach. Leachablility was further increased for metals when exposed to acidic conditions. / Master of Science

Environmental concerns about winter nitrogen (N) leaching loss limit the amount of biosolids applied to winter small grains in Virginia. Ten field studies were established 2012-2014 in Virginia to determine the agronomic and environmental feasibility of fall biosolids applications to soft red winter wheat (Triticum aestivum L.). Eight studies were located in the Coastal Plain physiographic province and two in the Ridge and Valley physiographic province. The effects of eight biosolids and urea N treatments on 1) biomass production at Zadoks growth stage (GS) 25-30, 2) soil inorganic N at GS 25-30, 3) soil mineralizable N at GS 25-30,4) N use efficiency (NUE) at GS 58, 5) grain yield, 6) end-of-season soil inorganic N, and 7) estimated N recovery were studied. Anaerobically digested (AD) and lime stabilized (LS) biosolids were fall applied at estimated plant available N (PAN) rates of 100 kg N ha⁻¹ and 50 kg N ha⁻¹. The 50 kg N ha⁻¹ biosolids treatments were supplemented with 50 kg N ha⁻¹ as urea in spring. Urea N was split applied at 0, 50, 100 and 150 kg N ha⁻¹, with 1/3 applied in fall and 2/3 in spring. Biomass at GS 25-30 increased with urea N rate and biosolids always resulted in equal or greater biomass than urea. Soil mineralizable N at GS 25-30 rarely responded to fall urea or biosolids N rate, regardless of biosolids type. Biosolids and urea applied at the agronomic N rate resulted in equal grain yield and estimated N recovery in soils where N leaching loss risk was low, regardless of biosolids type or application strategy. Lime stabilized biosolids and biosolids/urea split N application increased grain yield and estimated N recovery in soils with high or moderate N leaching loss risk. Therefore, AD and LS biosolids can be fall-applied to winter wheat at the full agronomic N rate in soils with low N leaching loss risk, while LS biosolids could be applied to winter wheat at the full agronomic N rate in soils with moderate or high N leaching loss risk. / Master of Science

Chalcopyrite ore forms the significant fraction of copper deposits in the earth crust. However, it is also the most difficult to treat using conventional ferric leaching methods. Smelting and electro-refining are currently the methods used in treating chalcopyrite concentrate obtained from froth flotation. Due to the ever increasing environmental requirements on smelters by the Environmental Protection Agency, new smelters are scarce in the United States. The scarcity of smelters has led to the urgent need to find a novel leaching method for the abundant chalcopyrite deposits in the USA and the rest of the world. This chapter(one) of the dissertation, therefore, investigated the leaching of chalcopyrite ore at pH 2 using a newly discovered oxidant (peroxodisulfate). Our results show that chalcopyrite leaching using peroxodisulfate follows a surface reaction shrinking core model. The activation energy of chalcopyrite leaching using peroxodisulfate ion was calculated as 41.1 kJ mol⁻¹. We also report that the leaching of chalcopyrite ore is affected by particle size and that stirring hurts leaching of chalcopyrite. Additionally, we found that peroxodisulfate can produce from sulfuric ions electrochemically. Hydrogen peroxide, permanganate, peroxodisulfate and ferric ions are all strong oxidants that have been researched in production pregnant leach solution (PLS) from chalcopyrite ore leaching. Because, solvent extraction is the next step in the recovery of copper from pregnant leach solutions (PLS). The questions, therefore, arises as to the fate of the organic extractant used in solvent extraction coming in contact with strong oxidant residual in the PLS. In chapter two of the dissertation, we studied the effect of strong oxidant residual in PLS on the degradation of organic extractants during solvent extraction of copper. Exposed organic extractants were analyzed using interfacial tension(IFT), Fourier Transform Infrared (FTIR) spectroscopy and CG LS. The results obtained from IFT and FTIR analysis, show no effect on the organic extractants exposed to sunlight and PLS containing the residual strong oxidant. Finally in chapter 3, the dissertation exams alternative water source for the flotation of chalcopyrite. Mineral flotation is a water-intensive process in mining. In order to sustain mining operations such flotation, which rely heavily on water, chapter 3 of the dissertation looks at using alternative water sources (in this case reclaimed wastewater) in the flotation of chalcopyrite ores; this effort is to limit the mining industries dependence on fresh ground water particularly in the Southwest of United States where water is a scarce commodity. The research studied the effect of reclaimed waste water on chalcopyrite flotation via contact angle and surface energy measurements. Furthermore, atomic force microscopy (AFM) and flotation tests were used to supplement the findings from contact angle and surface studies. We conclude here that the contact angle of a pure chalcopyrite surface was determined to be 75.6 degrees. We also found that pure chalcopyrite mineral surface is slightly polar with surface energies γCuFeS2^(LW) = 41.4 mJ/m² (apolar), γCuFeS2^(AB) = 2.9 mJ/m² (polar). The high value of the surface energy indicates pure chalcopyrite surface is slightly hydrophobic.