Добірка наукової літератури з теми "Sanitary landfills leaching environmental aspects Victoria"

Despite improved liner design, there are still reported incidences of landfill leachate, rich in heavy metals, percolating through to groundwater and threatening ecosystems. This thesis introduces the concept of segregating municipal solid wastes (MSW) according to their major heavy metals and their metal's adsorption compatibility. Each segregated portion can be disposed in a different landfill compartment to minimize leaching of these heavy metals with the greatest bioactive impact. The validity of the concept was evaluated by batch and column retention mobility studies using copper (Cu) alone or with either lead (Pb) or cadmium (Cd) in solutions bearing various pHs. This was supported by selective sequential extraction (SSE) to determine the affinity to specific liner fractions. The following summarizes the procedure used.
Beforehand, a soil column test using sand with 5 and 10% bentonite was conducted to develop an equation predicting liner permeability, k , under simulated field conditions. The column permeability test revealed that a liner with 5% bentonite resulted in a k value which respected the North American criteria of 10-5 m/s.
In the batch experiments, solutions with Cu alone or with Cd or Pb, adjusted to pH of 3.7, 5.5 or 7.5, were applied to sand liners with 0%, 5% or 10% bentonite, having CEC's of 2.0, 6.4, and 10.8 (cmol(+) kg-1 ), respectively. Bentonite, pH and Pb significantly affected Cu adsorption. Cu was adsorbed by the liners at pH <6.5 whereas Cu precipitated at pH >6.5. Cu retention was higher in the presence of Cd than in that of Pb, at all combinations of CEC and pH. Competition between metals was greater in liners with lower CEC and therefore fewer adsorption sites. Limiting Pb in a landfill compartment can improve Cu adsorption at pH's below the precipitating threshold.
In the SSE procedure, the liner samples were centrifuged, decanted from their solutions and each adsorption fraction analyzed for Cu content. Results indicated that the carbonate fraction adsorbed more Cu, and that Pb significantly increased the mobility of Cu due to competition for exchangeable sites.
In the final soil column test using a sand liner with 5% bentonite, the leachate had an initial pH of 3.7. The leaching test confirmed the compatibility of Cu with Cd. The leaching of Cu was greater in the presence of Pb. Total metals in leachate was greater for the Cu-Cd solutions than for the Cu-Pb, because of Cd's relatively high mobility. The sequential extraction results showed again that the carbonate fraction dominated metal adsorption. Total heavy metal leaching followed the order of Cu/Cd > Cu/Pb > Cu alone.
Thus, disposing MSW in landfill compartments based on their heavy metal compatibility can minimize migration of heavy metals.

This research involves the evaluation of municipal landfill leachates for specific hazardous compounds in an effort to qualitatively determine the potential for groundwater contamination. Leachate samples from five landfills were evaluated for thirteen EPA priority pollutants using gas chromatography. In addition, samples were analyzed for total organic carbon (TOC) and total organic halide (TOX). A solids analysis was performed on refuse excavated from one landfill. This analysis included organic halide determination of interstitial liquids, and a total halide determination for each solid sample. A solids/liquid partition coefficient was calculated from the results. The literature review includes a detailed section outlining the biological degradation of hazardous organic compounds in anaerobic environments similar to conditions found in landfills.

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