Thesis (M.S.)--Ohio University, November, 1994. / Title from PDF t.p.

Thesis--Academic Board of Wageningen University and Academic Board of the UNESCO-IHE Institute for Water Education, 2008. / Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [304]-309).

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (leaves 164-176). Also available in electronic version.

One of the problems associated with the disposal of solid wastes in landfills, particularly in high precipitation areas, is the pollution caused by the production of the often highly contaminated leachate. This study was initiated to investigate the treatability of a low-strength municipal landfill leachate using aerobic digestion followed by activated carbon polishing, so that the most cost effective treatment system could be determined. Sludge desorption and leachate toxicity assessment were also included in the study. The aerated lagoon process alone was very effective in treating the leachate to a quality that is nearly acceptable for discharge to a receiving water. Only SO₄ and Fe in the settled effluent significantly exceeded the local requlatory standards for specific discharges. Carbon adsorption greatly improved the settled effluent quality in terms of color, Fe and COD. However, the addition of this polishing process for combined treatment may not be cost effective. For an influent COD of 1,600 mg/1 and with MLVSS concentrations ranging between 360 and 560 mg/1, the settled effluent COD removal increased from 82.6% to as high as 90.1% when 9C was increased from 2 to 10 days. For the corresponding influent BOD5 of about 1,000 mg/1 and with θ[sub c] greater than 3 days, the BOD5 removal efficiencies averaged 99.1% and the settled effluent BOD5's were no greater than 10 mg/1. This indicates that the raw leachate can be almost completely biodegraded by aerobic digestion. The metal removal efficiency in aerobic treatment was greater than 95% for Fe and Mn, better than 90% for Zn and Pb, and about 80% for Al. Metals expected to be mainly or significantly removed by chemical precipitation due to pH change during treatment included Ca, Fe, Mn, Zn and Pb. Analysis of the kinetic parameters associated with the biological treatment indicated that the concentrations of pollutants, such as heavy metals, in the leachate were not great enough to cause significant inhibition of biological growth. It also showed that this leachate could very likely be added to a domestic sewage, in a high percentage, for aerobic treatment without producing adverse effects. From a treatment efficiency point of view, the optimum solids detention time was found to be 7 to 10 days for leachate BOD₅ ranging from 1,000 to 3,000 mg/1. However, since the predicted θ[sub c] for failure was 0.42 day at 22°C for a 1,000 mg/1 BOD₅ leachate, a θ[sub c] of 2 to 4 days seems possible in the field. On the other hand, the effects of winter temperature on BOD₅ removal and sludge settleability, as well as many other unknown factors on the overall biological treatment efficiency must be considered. It was, therefore, felt that a solids detention time of 5 days or more would be the more realistic approach for a full-scale treatment system, despite the fact that an economic analysis favored a shorter θ[sub c]. / Applied Science, Faculty of / Civil Engineering, Department of / Unknown

No description available.

Thesis (Ph.D.) -- McMaster University, 1997. / Includes bibliographical references (leaves 170-178). Also available via World Wide Web.

Thesis (M. Phil.)--University of Hong Kong, 1998. / Includes bibliographical references (leaves 69-74).

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

Habitat restoration is an important tool in reducing the current decline in biodiversity. To determine the success of restoration, ecologists have previously focused on species richness or on the presence of rare species; little is known of species interactions. This study examines both the potential of restored landfill sites to support pollinating insects and how flower-insect interactions can be used in determining successful restoration. These are important attributes of ecosystem function. Standard belt transects were used to record flowering insect pollinated plants and flower-visiting insects on nine paired restored landfill and reference nature sites, in the broader Northamptonshire region (UK). Over the duration of this study, an area of 25,000m2 was surveyed for floral characteristics and approximately 138,000 floral units were counted from 98 plant species. A total of 201 flower visitor surveys were performed, with 942 flower-visiting insect samples taken. Flowering plant species richness and abundance of floral resources on restored landfill sites were not found to be significantly different from those on reference sites and the flower-visiting insect assemblages were similar in terms of species-richness and abundance. Interaction structures were examined and whilst the plant-insect assemblages had few species in common, both showed similar levels of nestedness and connectance. The differences in the species but similarity in the functioning of these assemblages emphasise the importance of examining interaction structures within a functional approach to the evaluation of restoration. There are 2,200 landfill sites in England and Wales covering some 28,000 ha, and this study highlights that their restoration can potentially provide an important resource for the conservation of pollinating insects and the services that they provide for both natural and agricultural plants.