No description available.

The design characteristics of an active waste disposal capsule placed within a saturated groundwater environment is investigated, with the objective of developing a methodology to determine environmentally, technically and economically feasible conditions for its operation. In operation, conditions are created and maintained within and surrounding a containment cell to insure that a potential for convective inflow exists everywhere across an encapsulating barrier which tends to counter the potential for outward dispersion through the barrier. A computer algorithm based on the finite element method has been developed in the BASIC language to aid in the hydraulic analysis. Essentially, it provides a numerical solution to potential flow through porous media for two dimensional anisotropic solution domains of various materials. Data generated from this algorithm for cases of varying geometric material and boundary properties are used to verify and quantify assumed relationships involving critical design parameters which have been developed through dimensional analysis and physical reasoning. An expression describing the concentration profiles developed across the barrier is obtained by solving the one-dimensional convection-dispersion equation for steady conditions within and bounding the capsule barrier. Applying this result to an identified critical point allows conservative barrier design criteria to be developed so that operation of the active capsule results in only negligibly small amounts of contamination escaping through the barrier to the environment. By introducing cost coefficients which are descriptive of various aspects of construction, operation and maintenance of the active capsule, a total cost function is formulated from which, when minimized with respect to various design variables, optimizing criteria are developed. Finally, a predictor-corrector optimization program which incorporates the results of this study is developed and used to investigate an illustrative problem. / M.S.

Call number: LD2668 .T4 1985 R33 / Master of Science

Thesis (M.Sc. Environmental Science)--University of Waikato, 2008. / Title from PDF cover (viewed April 24, 2009) Includes bibliographical references (p. 138-147)

Accurate and detailed costs for individual municipal waste collection, treatment and landfill methods are not readily available. Neither is there a reliable means of comparing between two or more alternative options. However, before improvements to the management and planning of solid waste disposal can be achieved both are required. Currently, comparisons and planning in this field are highly ambiguous, often misleading, with individual operators using widely different accounting conventions and operating standards. The purpose of this work has been to establish accurate comparisons. Initially, detailed financial and technical information \'las collected from numerous operators, and then a standard basis for comparison (the "base case") was derived onto which the costs obtained were adjusted. Cost functions were also generated to interpret component costs fora range of sizes of operation. The economics of five collection methods, four transfer methods, seven bulk transport vehicle types and several landfill disposal variations are considered. For each a detailed appraisal of the component capital and operating costs has been made so as to identify the largest expenditures. The effect of uncertainty on cost estimates was also emphasised and explicitly considered by sensitivity analyses on selected economic and physical parameters. These analyses have indicated those component costs which exert the most significant influence on the total costs, and as such should be the most closely monitored by a waste manager. One notable example is the sensitivity of total landfill costs to leachate treatment. Six case studies are also presented. These are designed to demonstrate the versatility of the cost models derived and also the method developed for unambiguous economic comparison. This research provides a large financial data base on all of the collection, transfer and landfill methods in common use in Britain. Use of this information and the principles for comparison put forward would enable waste managers to incorporate sound financial appraisals into both their operational and forward planning decisions. This should subsequently improve not only the quality of their decisions but ultimately the standard of service they offer too.

The concentration of phenols in the soils environment and their fate was studied as a function of five different soil types, six different monohydroxyphenols, and three different municipal landfill leachates media. Concentrations of naturally occurring phenols were also followed for a period of one year in young and old leachates. Methods for analysis of phenols were reviewed for quantitative and qualitative analysis of phenols in landfill leachates. To determine the adsorptive capabilities of the soils used in this study, the isotherm approach was used after the equilibration time of phenols in soils was determined to be five days. Concentrations of phenols varying from 5 ppm to 100 ppm were used to construct isotherm graphs. The soil-phenol isotherm curves conformed very well to the Freundlich equation, indicating multiple adsorption mechanisms and slow equilibration times in the soilsphenols reactions. A statistical analysis of the isotherm data showed %-free iron oxides to be the most important soil characteristic for the adsorption of phenols by all soils; followed by soil pH and % clay in order of significance. High solubility and moderate polarity of phenols also were found to be favorable factors in the adsorption of phenols by soils. Naturally occurring phenols such as cresols disappeared fastèr from soil solutions than synthetic phenols. The reactivities of phenols with MSW leachates increased with the age of the leachates. Very young leachates, having low pH and high TOC levels favored synthetic phenols over naturally occurring phenols to react with. All leachates studied demonstrated an ability to remove from solution one or more of the six phenols used in large quantities over a period of 15 days or less. The overall performance of the leachates used in this study seemed to be a function of the humic acid levels found in them. Levels of naturally occurring phenols in leachates varied from several ppbs to more than 9000 ppbs for a year's period. The highest phenol levels were found in the young phenols and the lowest levels in the old phenols; indicating that pH and TOC concentration determine the amounts of phenols in solution. In column studies of perfusion of leachates through 10 cm of soil materials packed at field densities, no soil was able to stop the migration of phenols for more than 5 to 10 pore volume displacements. Low pH and high TOC levels seemed to play a much larger role in the migration of phenols through soils than the levels of phenols found in the leachates used. The use of phenol enriched deionized water passed through soil columns showed the fact that there is a clear dependency of adsorption of phenol on the flow rate. Slow rates favored adsorption of phenol by all soils studied. The TOC analysis of the effluents from the phenol enriched water-soil columns studies indicated that some mechanisms for the disappearance of phenol from soil solution may have been transformation reactions as well as adsorption reactions. Varying TOC levels with flux seemed to indicate that these reactions are much slower than the adsorption reactions. The use of Cu⁺² saturated soils in an attempt to correlate transformation reactions of phenol with transition metal catalytic properties failed to increase the adsorption and/or transformation of phenol in the soil media. The 4-aminoantipyrine colorimetric method performed well in the analysis of phenols in air unstable leachates. Gas-liquid chromatography using NPGSB+H₃PO₄ on Anakrom A 90/100 mesh was used for the quantitative and qualitative analysis of phenols in leachates.

No description available.

Porous plates delivered calcium chloride at a negative potential to the top of blocks of partially welded (20.1 x 20.1 x 66.6 cm) and densely welded (30.1 x 20.1 x 48.1 cm) tuff with discrete fractures. During infiltration, flux increased through the partially welded block's fracture as the applied suction was lowered to 2.3 cm. The wetting front advanced 66.6 cm in 239 days. Chloride concentration and temporal moments from five tracer tests with 0 to 5 cm of applied suction indicated that preferential fracture flow occurred. Displacement transducer data reflect a decrease in fracture aperture at several months prior to but not during tracer tests. Fracture transmissivities decreased an order of magnitude (6.4 x 10⁻⁹ to 4.2 x 10⁻¹⁰ M²/s) as the applied suction increased from 0 to 5 cm while the tensiometer data indicated a suction of about 20 cm of water within the fracture and matrix. Highest during infiltration to an initially dry block, inflow losses of 3 to 44 percent due to evaporation are the greatest source of error for the constant potential method used.

Dissertation submitted in compliance with the requirements for the Master's Degree in Technology: Biotechnology, Technikon Natal, 2001. / Landfills play an important role in the removal of waste from the surroundings. There is a limit to the types of waste that can be recycled and the landfill becomes the final method of waste disposal. Because waste constitutes a wide variety of materials, the microbial consortia that develop within a landfill will be equally varied, depending on the type of waste deposited, the temperature of the landfill and moisture content of the waste. The metabolism of these microbial consortia can result in products that are either harmful or beneficial. In order to increase the pool of knowledge on landfill microbiology, it is important to study the various consortia that inhabit the landfill to determine the various microbial interactions that occur and subsequently to manipulate these interactions to enhance the benefits of a landfill site and reduce the harmful effects. In this research, an attempt was made to isolate anaerobic cellulolytic bacteria from a landfill site. Six waste samples, varying in age were obtained over a period of two years. Samples were excavated from a maximum depth of 4m. Samples are processed in anaerobic, phosphate buffer and cultivated in various pre-reduced anaerobic media and incubated under anaerobic conditions. Samples were also collected from other potential anaerobic sites namely, anaerobic sludge, decomposing bagasse, compost, manure, rumen and pond sediment. Results of degradation of the cellulose source (Whatman No. 1 filter paper) indicated that it was possible to cultivate cellulose-degrading microorganisms from the landfill. Zones of clearing around colonies, which would be indicative of cellulose degradation on solid media, were not obtained. Samples from the anaerobic sludge, compost and rumen showed degradation of cellulose in liquid media but not on solid media. It is concluded that the solid media used was unsuitable for the cultivation of anaerobic, cellulolytic bacteria or that the anaerobic conditions employed were not adequate to initiate the growth of the anaerobic cellulolytic bacteria. / M

Thesis (MTech (Agriculture))--Cape Peninsula University of Technology, 2014. / In this study, laboratory and greenhouse experiments were conducted to evaluate the effects of utilization of land fill leachate for irrigation purposes on potted soil and Swiss chard, to provide more insight into effects of landfill leachates on the environment. Swiss chard was grown and irrigated with different concentrations of leachates in pot experiments. For several weeks, the experimental soil and Swiss chard leaves was analyzed to assess extent of change in different chemical compositions, post-irrigation. The leachate samples had a high electrical conductivity (mean = 383 mS cm-1) and high soluble salts content (mean values, Na = 714.5 mg/L, K= 56.8 mg/L, Ca = 133.7 mg/L, Mg = 68.8 mg/L, Cl = 983 mg/L); while the composition of heavy metals in these wastewater leachates were of low concentrations. The application of leachates in irrigation resulted in increased soil cation concentrations, particularly those of Na ions (increased sodicity). Similarly, an increase in electrical conductivity and pH were recorded in the soils after irrigation with leachates. The soil metal concentrations were low and there was no significant difference in soil heavy metal concentrations between the soils irrigated with leachate and those of the controls. The results also show significant (p <0.05) reduction (up to 50%) in Swiss chard growth with application of (100%, 50% and 25%) of leachate as source of irrigation water compared to the growth observed in leachate-free (control) irrigation systems. This reduction in growth was best attributed to the high cation content in plant tissue picked up from the soil which was high in cations as a result of leachate irrigation.