Date of Award

2003

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Civil and Environmental Engineering

First Advisor

Bewtra, J. K.,

Keywords

Engineering, Sanitary and Municipal.

Rights

CC BY-NC-ND 4.0

Abstract

Due to recent stringent environmental regulations and a high potential for soil, surface and ground water pollution, disposal of landfill leachate has become a problem in handling solid wastes from municipalities. Therefore, landfill leachate treatment is required as an essential part of the solid waste management. A wide range of high to low technologies is available for partial or full, on site treatment of municipal landfill leachates. The current research work demonstrates the potential of using floating aquatic plants, such as water hyacinth (Eichhornia crassipes) and giant salvinia (Salvinia molesta), for treatment of municipal landfill leachate. The experiments were carried out in seven phases. In the first phase, the ability of water hyacinth and giant salvinia to treat leachate was investigated. Phases Two and Three were carried out to investigate the growth and tolerance of water hyacinth plants, the successful plant, to certain salinity ions present in leachate. The effect of nutrient addition to the system was also investigated. The effect of leachate pH on the growth of water hyacinth and the removal of nitrogen were investigated in Phase Four. The last three phases were conducted to study the ability of water hyacinth to remove five heavy metals (Cr, Cu, Cd, Ni and Pb) commonly found in leachate. In Phases Five and Six, living biomass was used, whereas in Phase Seven, dry plant tissues were used. All experiments were conducted in batch reactors in a green house environment. The leachate samples were collected from Essex-Windsor Regional Landfill, Windsor, Ontario, Canada. Water hyacinth showed better performance than salvinia, with regard to growth in different leachate dilutions and removal of certain pollutants. Optimum growth took place when the initial chloride and sodium concentrations were 560 mg Cl L-1 and 330 mg Na L-1, respectively. The presence of chloride and sodium ions, up to a concentration of 1000 mg Cl L-1 and 600 mg Na L-1, in landfill leachate, with proper pH values, promoted the growth of plants. The optimum pH range for the leachate treatment with water hyacinth was from 5.8 to 6.0. However, it was observed that the plants could survive in a wide pH range of 4.0 to 8.0. It was found that living biomass of water hyacinth was a good accumulator for Cr, Cu and Cd. However, Pb and Ni were poorly accumulated in water hyacinth. Mathematical models for the prediction of metal removal by living biomass of water hyacinth were developed. Dry tissues of water hyacinth, shoots, roots and shoots + roots, also showed the ability to remove only cations from leachate. The removal was affected by the medium pH. The results indicate that typical leachates from both new and old landfill sites (more than 5 years) are amenable to water hyacinth treatment system, with regard to the effects of pH, chloride and sodium ions, and heavy metal concentrations on the plant growth.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2003 .E44. Source: Dissertation Abstracts International, Volume: 64-06, Section: B, page: 2893. Advisers: J. K. Bewtra; N. Biswas. Thesis (Ph.D.)--University of Windsor (Canada), 2003.

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