The current Environmental Protection Agency (EPA) method utilized for analysis of trace organic chemicals and heavy metals leached from solid waste is the Extraction Procedure (EP) Toxicity Test. Because of various operational problems and limitations of the EP, the EPA has developed and plans to implement the Toxicity Characteristic Leaching Procedure (TCLP), which is an expanded version of the EP capable of analyzing more organic components, in particular volatile organic chemicals. The purpose of this research was to investigate and compare the ability of the EP and TCLP test procedures to quantitatively recover added surrogate standards (1,2-dibromoethane, bromoform, 1â chlorooctane, fusarex, heptachlor, and DDT) and also qualitatively identify and evaluate unknown trace organic chemicals in domestic wastewater sludges. In order to meet the research objectives established, three small (approximately 1 MGD or less) municipal wastewater treatment plants that land applied their sludges were analyzed. / Master of Science

This investigation has been carried out for the purpose of determining the effect of solid particle size distribution on the roasting and leaching of a complex sulfide ore. The effect of pulp density in the leaching process has also been studied. The oxidizing roast of the combined sulfide concentrates, prepared by bulk sulfide flotation and tabling, was conducted with a fluidized-bed kiln. The calcines were leached by dilute sulfuric acid in an autoclave. The following conclusions have been reached: 1. In the fluidized-bed roasting, the solid particles within the size range of minus 35 to plus 150-mesh would have a higher overflow rate from the fluidized bed. This inference might be effective only when the roasting is conducted under the conditions performed in this investigation. 2. In the process combining fluidized-bed roasting and dilute sulfuric acid leaching, the effect of solid particle size is significant. The solid particles within the size range of minus 65 to plus 150-mesh have the highest iron recovery, the highest copper and zinc extraction rates and the lowest sulfur content of leach residue. 3. In dilute sulfuric acid leaching there is no significant effect of pulp density within the range tested in this investigation. The general trends are: iron recovery decreases as the pulp density decreases, extraction rates of copper and zinc decrease as pulp density increases, and there is little pulp density effect on the sulfur content of leach residue. / Master of Science

This investigation deals with the application of high pressure and high-temperature leaching techniques to separate out zinc and copper from the iron constituents of a calcined sulfide ore. An important variable in this study proved to be the concentration of the leaching reagent -- sulfuric acid. The leaching temperature was varied within a range of 250°F to 550°F., and 8 cubic centimeters to 20 cubic centimeters of sulfuric acid in 2000 cubic centimeters of distilled water was employed as the leaching agent concentration. The major equipment utilized for roasting was the fluidized bed and an autoclave for leaching. After the physical and chemical treatments of roasting and leaching of the calcine, the resulting constituents were studied by means of quantitative chemical analysis. Numerical theories were used to correlate the points obtained into continuous functions of the leaching temperature, concentration of sulfuric acid and the recovery percentage. From these curves, it is concluded that the recovery of the impurities in the calcine is proportional to the leaching temperature and the concentration of the leaching agent. However, under certain circumstances, the leaching action causes loss of iron in the calcine, and the minimizing of the loss in leaching is also studied. / Master of Science

A framework for evaluating the risk of water pollution from the application of liquid dairy manure to agricultural fields was developed and applied. The GLEAMS (Groundwater Loading Effects of Agricultural Management Practices) (Ver 2.1) model was used to simulate NO₃-N leaching below the root zone for different land application rates of liquid dairy waste for fields in Georgia and Texas. Probability distributions of yearly-maximum nitrate concentrations were developed for each application rate at each site using the simulated nitrate concentrations. The probability of failure (exceeding 10 mg/L NO₃-N) for each application rate was determined from its corresponding distribution. An appropriate fine for farmers based on probability of failure for different land application rates was determined through economic analysis. The expected risk to farmers in monetary terms was determined for each application rate based on possible fines and the probability of failure. The monetary risk of nitrate leaching to ground water was compared to the social value of ground water. The probability of failure for liquid dairy waste application rates between 200 to 800 kg·N/ha/yr ranged from 0.0022 to 0.74 for Tifton, GA. The probability of failure for liquid dairy waste application rates between 0 and 1000 kg·N/ha/yr ranged from 0.00 to 0.85 for Overton, TX. The maximum application rate that was environmentally acceptable for both Texas and Georgia was 250 kg·N/ha/yr based on the probability of failure. Fines of $1100/ha and $700/ha for the Georgia and Texas sites, respectively, would provide farmers with economic incentives not to exceed an application rate of 250 kg·N/ha/yr. These fines resulted in risks to farmers of $814/ha in Georgia for 800 kg·N/ha/yr application rate and $595/ha in Texas for 1000 kg·N/ha/yr rate. This compares with a social value ranging from $860/ha to $1432/ha of clean ground water. / Master of Science

The stoichiometric Self-propagating High-temperature Synthesis (SHS) thermite reaction involving magnesium oxide (MgO), titanium dioxide (TiO₂), and boron oxide (B₂O₃) forms titanium diboride (TiB₂) and MgO as final products. Selective acid leaching is used to remove the MgO leaving high purity TiB₂ powder. The SHS method to produce TiB₂ is attractive because of the relatively low temperature required to initiate the reaction, fast reaction time, and product purity. This study investigates the acid leaching of SHS produced MgO/TiB2 and a stoichiometric mixture of commercial MgO and TiB₂ powders. Leaching was conducted at 90° C, 60° C, and 30° C at pH levels of 4.0, 2.5, and 1.0 by introduction of concentrated aliquots of HNO₃. This method maintains a minimum pH target throughout the leaching process, thereby sustaining a dynamic concentration to remove the oxide. The optimal leaching conditions were determined to be at 90° C at a minimum pH target of 2.5 for the SHS produced product. At these conditions, conversion percentages of 83%-84% of MgO were measured with only trace amounts of TiB2 measured in the solution (less than 100 ppm). Conversion percentages for each leaching condition and dissolution mass of solid MgO and TiB₂ at each pH are also reported. Results from powder XRD confirm the removal of MgO and minimal dissolution of TiB₂, and indicate the formation of unidentified compounds. Inductively coupled plasma mass spectrometry (ICP) was used to analyze the ionic composition and extent of leaching. Scanning electron microscopy (SEM) was used to observe the particle morphology of the leached powders. / Master of Science

Brass components are widely used in drinking water distribution systems as valves, faucets and other fixtures. They can be corroded by "dezincification," which is the selective leaching of zinc from the alloy. Dezincification in potable water systems has important practical consequences that include clogged water lines, premature system failure and leaks, and release of contaminants such as lead. Brass failures attributed to dezincification are known to occur at least occasionally all over the world, and have emerged as a significant problem in the U.S. recently due to the use of inexpensive high zinc brass fittings in cross-linked polyethylene (PEX) plumbing systems. As PEX systems gain popularity and leaded brass is recognized as an important source of lead in potable water systems, it is important to examine dezincification corrosion in more detail. An in-depth literature review revealed that conventional wisdom about dezincification was no longer adequate in explaining failures observed in modern water systems. Little research has been conducted since the landmark work of Turner et al. nearly half a century ago. The potential role of chloramines, phosphate inhibitors, and modern understanding of water chemistry need evaluation. The role of physical factors including stirring, heating and galvanic connections are also potentially influential. A mechanistic study of zinc solubility and corrosion of copper: zinc couples provided insight to factors that might mitigate and exacerbate zinc leaching from brass. Zinc solubility and corrosion was reduced by higher pH and bicarbonate, but was enhanced by higher chloride. Hardness ions including Mg⁺² and Ca⁺² had little effect. Alloys with higher zinc content had a greater propensity for dezincification corrosion. Stirring and galvanic connections caused brass to leach more metals and have higher weight loss. Heating may contribute to corrosion scale accumulation. A comprehensive examination of dezincification as a function of water chemistry used numerous techniques that include measurement of galvanic currents, metal leaching, and weight loss. In general, as would be predicted based on results of the study of solubility and corrosion of pure zinc, chloride emerged as an aggressive ion whereas bicarbonate was beneficial to brass corrosion. Hardness had little impact, and phosphates, silicates and Zn+2 inhibitors had a significant short-term benefit but little long-term benefit. The relationship between dezincification corrosion, lead leaching from brass, and water chemistry was investigated in Chapter 5. Surprisingly, lead and zinc leaching from a range of brasses were found to be negatively correlated. Hence, use of brasses that minimize dezincification problems might increase lead leaching. This thesis represents a comprehensive analysis of factors that are influential for dezincification and lead leaching from brass in premise water distribution systems through literature reviews, mechanistic investigations, bench-scale experiments, and case studies. Results can be used by water utilities, plumbing engineers, manufacturers and home owners to better prevent, recognize, and mitigate brass and dezincification corrosion problems. / Master of Science

No description available.

京都大学 / 新制・課程博士 / 博士(地球環境学) / 甲第24955号 / 地環博第246号 / 新制||地環||49(附属図書館) / 京都大学大学院地球環境学舎環境マネジメント専攻 / (主査)教授 勝見 武, 准教授 高井 敦史, 教授 越後 信哉 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM

M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology / Several technologies are currently being developed to mitigate the greenhouse gas CO2. One of these promising processes is industrial mineral carbonation whereby alkaline industrial wastes are taken as raw material. The process is a multi-step process which involves the extraction of calcium from industrial alkaline wastes and the subsequent reaction of extracted calcium rich supernatant with CO2 at elevated pH to form stable carbonates. Steelmaking slags were selected from four different plants in SA and used for this investigation owing this to their high calcium content. The potentially-suitable four slags were selected on the basis of their Ca content and high chemical reactivity. The objective of this investigation was to develop a common leach process for all four steel slags to achieve a complete Ca extraction from slags. A Ca rich solution was carbonated to achieve a stable carbonate that can be used. Experiments were carried out using ammonium reagents and a hydroxide reagent to investigate their suitability for the rapid, selective extraction of calcium. Calcium was leached under different experimental conditions including varying leachant concentrations, temperatures and solid to liquid ratios. The slags exhibited contrasting reactive properties to different leachants, which can essentially be explained in terms of differences in mineralogical composition, hence mineral solubility characteristics. Leaching with 2M NH4NO3 aqueous solution at room temperature extraction efficiency increased with increasing concentration. The extent of extraction was different for the four slags. WMO5 showed a complete dissolution of Ca within 20 min of experiment. This difference is due to their different Ca-containing minerals. Same is observed with aqueous NH4CL but WMO5 did not reach a complete dissolution as with NH4NO3. Aqueous NaOH made it impossible for Ca extraction due to its high pH and upon slag addition it was more elevated. Increasing solid to liquid ratio had an influence in percentage slag loss. The pH of leach solution was elevated to 9 making it difficult to extract Ca. Under controlled conditions (pH kept under 1) optimal slag dissolution was achieved with traces of larnite and large amount of brownmillerite. The generated Ca-rich leachate was carbonated in a 600 ml reactor vessel with liquid CO2. A stable carbonate aggregate was produced. / Council for Geoscience Vaal University of Technology

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