Thesis (M.A.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 69-72).

Thesis (M.L.A.)--University of Hong Kong, 2005. / Includes special report study entitled: Landfill surface design considerations.

Thesis (M. L. A.)--University of Hong Kong, 2007. / Title proper from title frame. Includes special report study entitled: Restoration with native species in Hong Kong hillside. Also available in printed format.

Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 152-153).

Thesis (Ph.D.)--Tennessee Technological University, 2006. / Bibliography: leaves 590-601.

One particularly undesirable aspect of solid waste disposal on land is the contamination of water passing through the landfill site. The potential adverse environmental effects of these "leachates" have been recognized to the extent that their control and treatment is the subject of a great deal of current research in water pollution control. This study was initiated to investigate the possibility of reducing the amounts of oxygen demanding material in a high-strength landfill leachate by aerobic biological methods, without any prior removal of the heavy metals contained in that leachate. The effect of varying solids detention time was also investigated and the distribution of the heavy metals in the effluents was examined. Using very high mixed liquor volatile suspended solids concentrations, 8,000 to 16,000 mg/l, and a combination of air and mechanical mixing, anticipated foaming problems were controlled and stable digester operation was maintained at solids detention times as low as 10 days. For influent COD concentrations between 44,000 and 52,000 mg/l, settled effluent COD removal increased marginally from 96.8 to 99.2 percent, as the solids detention time increased from 10 to 60 days. Mixed liquor COD removal similarly increased from 51.5 to 75.7 percent. Increasing the solids detention time from 10 to 20 days, significantly improved the quality of the settled effluent with respect to oxygen demanding material. At solids detention times greater than 20 days, and with influent BOD₅ between 32,000 and 38,000 mg/l, settled effluent B0D₅ averaged 58.1 mg/1, as opposed to settled effluent BOD₅ greater than 125 mg/l when the solids detention time was 10 days or less. The leachate feed used in these studies contained a variety of heavy metals including aluminum (41.8 mg/l), cadmium (0.39 mg/l), chromium (1.9 mg/l), copper (0.24. mg/l), lead (1.44 mg/l), nickel (0.65 mg/l), and zinc (223 mg/l). Most of these metals including aluminum, cadmium, chromium, nickel and zinc were almost completely removed by the settling biological floe. Others were associated with the sludge solids to a lesser extent. Analysis of the kinetic parameters associated with the biostabilization process indicated that the high heavy metal concentrations in the mixed liquors inhibited the actual biological removal of oxygen demanding material in the digesters tested. The settling biological floe was found, however, to remove greater than 97 percent of the mixed liquor BOD₅ and greater than 96 percent of the mixed liquor COD when solids detention times were maintained greater than 20 days. Therefore, for best treatment results a solids detention time of at least 20 days is recommended and the food to micro-organism ratio should be kept below 0.15 lb.BOD₅/lb.MLVSS/ day. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Thesis (M.S.)--Ohio University, August, 1992. / Title from PDF t.p.

A relatively new concept of Municipal Solid Waste treatment is known as bioreactor landfill technology. Bioreactor landfills are sanitary landfills that use microbiological processes purposefully to transform and stabilize the biodegradable organic waste constituents in a shorter period of time. One of the most popular types of bioreactor landfills is the landfill with leachate recirculation. However, it is observed that ammonia rapidly accumulates in landfills that recirculate leachate and may be the component that limits the potential to discharge excess leachate to the environment. In the facultative landfill, leachate is nitrified biologically using an on-site treatment plant and converted by denitrifying bacteria to nitrogen gas, a harmless end-product. In this research, three pilot-plant scale lysimeters are used in a comparative evaluation of the effect of recirculating treated and untreated leachate on waste stabilization rates. The three lysimeters are filled with waste prepared with identical composition. One is being operated as a facultative bioreactor landfill with external leachate pre-treatment prior to recirculation, the second is being operated as an anaerobic bioreactor landfill with straight raw leachate recirculation, and the third one is the control unit and operated as a conventional landfill. Apart from environmental restrictions, geotechnical constraints are also imposed on new sanitary landfills. The scarcity of new potential disposal areas imposes higher and higher landfills, in order to utilize the maximum capacity ofthose areas. In this context, the knowledge of the compressibility of waste landfills represents a powerful tool to search for alternatives for optimization of disposal areas and new solid waste disposal technologies. This dissertation deals with and discusses the environmental and geotechnical aspects of municipal solid waste landfills. In the Environmental Engineering area, it compares the quality of the leachate and gas generated in the three lysimeters and discusses the transfer of the technology studied through lysimeters to procedures for full-scale operation. In the geotechnical area, this dissertation discusses the compressibility properties of the waste and provides a state-of-the-art review of MSW compressibility studies. It also evaluates the compressibility of MSW landfills for immediate and long-term settlements and proposes a new model for compressibility of waste landfills.

Thesis (M. Sc.)--University of Hong Kong, 1994. / Includes bibliographical references (leaf 78).

by Yu Chung Toi Samuel. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1986 / Bibliography: leaves 147-154