An extensive series of experimental tests were carried out at the Sheffield municipal solid waste incinerator plant (30 MW) from September 1988 to July 1989 to investigate the influence of the design and operating parameters on the performance of the incinerator which burns domestic and commercial wastes (500 ton/day). The following measurements were made around the plant: temperature measurements, pressure measurements, flue gas composition analysis and determination of physical and chemical properties of Sheffield refuse. Several other miscellaneous measurements were also made to monitor the effect of variation of operating parameters on the performance characteristics of the incinerator. A combustion model of Essenhigh type was then employed to model the combustion processes inside the solid refuse bed on top of the travelling grate. In addition a mathematical model of the finite difference type (FLUENT) was used to predict the three dimensional reacting flows (gaseous phase) within the incinerator geometry. Experimental measurements of gas composition, temperature and exit velocity were compared with model predictions. Modelling results were generally in good agreement with measurements. As a result of the test data and the mathematical modelling of the whole process, suggestions for design improvements for the Sheffield municipal solid waste incinerator were made which will substantially increase the efficiency, reduce emissions of pollutants and reduce the maintenance costs at the plant. These are: a) replacing the existing secondary air system with secondary air nozzles and the use of more secondary air (up to 20 % of total air) in order to generate turbulence in the high intensity combustion zone where it is most needed and b) introducing a baffle into the main stream inside the radiation shaft in order to lower the gas temperatures entering the precipitator and to remove the existing recirculation zone in the shaft.

The response of the lux-biosensors to a range of environmental pollutants was determined, as well as the stability of the biosensors to a range of environmental parameters. The biosensors were found sensitive to a range of pollutants at environmentally relevant concentrations. These included the pollutants prevailing at the contaminated site (BTEX and major co-contaminants). Analysing the bioluminescence dose-response curves to different pollutants, it was observed that the shape of the response appeared to be indicative of the nature of the contaminant present. The application of the lux-biosensors in the screening of groundwater and sediment samples from the contaminated site, showed different levels of toxicity which correlated well with chemical analysis. The sample screening produced a toxicity map of the site, facilitating the identification of hot-spot areas that could be further investigated. Samples with high levels of toxicity were serial diluted and dose-response curves determined to increasing concentrations of the toxic sample, in site uncontaminated groundwater. The shape of the dose-response curve was indicative of the nature of the main pollutant present. The toxic effect of a pollutant detected by the biosensors in spiked environmental samples (groundwater from the study site) correlated with the effect of the same pollutant on mineralisation. This allowed subsequent use of biosensor toxicity for predictive assessment of degradation potential in the presence of the pollutant tested, validating the use of the lux bioassay as a management tool for bioremediation. The bioremediation of the major contaminants (BTEX) on site can be constrained by the presence of co-contaminants or adverse environmental conditions that inhibit microbial activity. The determination of these constraints is crucial for the success of the bioremediation technologies. Using biosensor response linked to sample manipulations, it was possible to determine the contribution of broad classes of pollutants to the total toxicity of the samples.

No description available.

Three techniques are investigated in order to assess their applicability for use in landfill design, construction and monitoring. Firstly, an assessment is made of QA procedures during liner construction through the detailed evaluation of two case studies. Construction QA procedures on-site are compared to available guidelines. The research illustrates the requirement for standardised, regulated QA procedures on landfill sites in order to provide a recognised framework for construction control. The Moisture Condition Value Test (MCV) is evaluated for use as a method of monitoring the placement of compacted clay landfill liners. London Clay and Mercia Mudstone, collected from the QA case study sites, are tested in terms of their suitability as engineered clay liners. Although, London Clay is the most acceptable it is this material which exhibits the poorest results in the MCV testing. This is due to seepage from the apparatus at high moisture contents. The research highlights the problems with the interpretation of the protocol for the testing and the differences between the Scottish and English Road Research Laboratory guidelines (Green & Hawkins, 1987). Thirdly, two airborne remote sensing techniques (ATM and CASI) are appraised as methods of monitoring landfill gas, or possibly leachate migration, from two case study landfill sites in South West England. Vegetation stress can be linked to landfill gas migration (Flower et al., 1981) and this stress can be detected as a deviation from normal spectral reflectances in vegetation (Honer et a!., 1983a). Anomalies are identified on-site through remote sensing but they cannot be directly attributed to the landfills. This research emphasises the effects of contamination from other sources. It also requires the use of a simultaneous ground survey to collate data from boreholes with measurements of soil and vegetation types. Essentially, the QA case studies and the remote sensing show potential for future use and suggestions are made in this thesis for further research. The MCV technique provides a method for assessing the controlling parameters of compaction. With further development of aspects outlined in this investigation there is the potential for specified use of these techniques In landfill engineering and monitoring.

Geossintéticos são materiais cada vez mais aplicados em aterros sanitários, cumprindo diferentes funções como barreiras para líquidos e gases. Na função de filtração, o uso destes materiais não está consagrado, principalmente, em função da possível colmatação total ou parcial dos geotêxteis por ação de microrganismos, a chamada colmatação biológica. Neste contexto, o presente trabalho visa avaliar a colmatação de geotêxteis tecidos e não tecidos submetidos ao fluxo de lixiviado de aterro sanitário. Foram utilizados três geotêxteis não tecidos de gramatura 200 g/m², sendo um de filamento contínuo de poliéster (PET) e dois de fibra curta, porém fabricados com polímeros diferentes poliéster e polipropileno (PET e PP) e um geotêxtil tecido de polipropileno, com gramatura 400 g/m². Para avaliar a colmatação dos geotêxteis montaram-se ensaios de permeabilidade de longa duração em que se mediu a condutividade hidráulica ao longo do tempo. Após os ensaios de permeabilidade, realizou-se microscopia eletrônica de varredura para avaliar o fechamento dos poros dos geotêxteis, além de avaliar o crescimento bacteriano ocorrido no interior do geotêxtil. Os resultados obtidos permitem constatar significativa redução da condutividade hidráulica dos materiais após o período de 30 dias de ensaios, onde notou-se a predominância do processo de cegamento. / Geosynthetics materials have been intensively used in landfills in different functions as liquid and gas barriers. As filters, geosynthetics are not completely accepted in designs, since total or partial geotextile clogging can occur for biotic deposition (or impregnation), usually named biological clogging. This work evaluates the clogging on nonwoven and woven geotextiles under leachate flow for landfill application. For this purpose, nonwoven geotextiles with short and long polyester filaments and mass per unit area of 200 g/m² were used, as well as polypropylene and polyester nonwoven geotextiles with mass per unit area of 400 g/m². Cross-plane permeability tests were periodically conducted in geotextiles samples which were under long term leachate flow. After each permeability test, scanning electron microscopy (SEM) was conducted to evaluate the source of pore geotextile clogging, as well as the bacteria growing into the geotextile matrix. Results have shown a significantly reduction on hydraulic conductivity of geotextile filters after 30 days of leachate flow, which was motivated by blinding process.

The UK contains 5000 unlined historical landfills in the coastal zone currently at risk of erosion within the next 50 years. These rely on natural attenuation in surrounding sediment to reduce the contaminant load to the environment. This thesis investigates the extent and magnitude of sediment metal contamination from historical estuarine landfills. An intensive investigation of Newlands historical landfill, Essex, indicated elevated metal concentrations in surface and sub-surface sediments. Surface sediment concentrations were similar to other industrially impacted estuaries, whilst peak metal concentrations at c. 50 cm depth were indicative of industrial activity in the mid-20th Century. Below this depth, sediments were enriched with Pb (EF > 2) and Zn (EF = 1.5) indicative of an historic leachate plume that extends c. 15 m from the landfill site boundary. These sediments present a secondary source of diffuse pollution and a site contamination load of c. 1200 kg Pb. In-situ XRF was demonstrated as a rapid contamination screening tool for Fe, Pb, Sr and Zn enabling a broad-scale investigation of historical landfills across SE England. Sediment cores from eight sites containing both hazardous and inert waste were screened. Concentrations and EFs of Pb and Zn at depth were significantly higher in hazardous sites compared to inert sites. Spatial distributions of Pb and Zn were comparable to Newlands historical landfill. This indicates that diffuse pollution from historical landfill sites with similar chemical and physical attributes to Newlands is likely to present a regional, if not national problem, with UK historical landfills presenting contaminated sediments, comprising a significant, previously unidentified and unquantified diffuse pollution source in the coastal zone.

The aim of this project was to identify a suitable solution to the problem of landfill leachate at the North Katoomba landfill site. Options were affected by a range of constraints including economics, location and the intrusion of ground water into the landfill. The initial goal was to contain and treat the leachate on site, with the eventual target to discharge into the nearest receiving waters. A constructed wetland option was devised and researched, involving identification of the major pollutants contained within the leachate, developing a concept design and estimating the likely removal efficiencies expected. Investigations identified the primary pollution parameters as microbial and nutrients. Metals were found to be low in concentration although the wetland has the capacity to deal with these pollutants should they become part of the pollution plume. A bench scale constructed wetland system was developed to give an indication of the removal efficiencies. The results suggest that a constructed wetland system would be appropriate for treating landfill leachate at the North Katoomba site. It is recommended that a constructed wetland be established in the field to determine the long term treatment prospects and the potential management problems in a practical application. / Master of Science (Hons)

Landfills are a potential pollution threat to both ground and surface water resources. This study focuses on two landfills, the Horotiu municipal waste landfill, near Hamilton, New Zealand, and the Maseru landfill in Lesotho. The Horotiu landfill is located less than 50 metres from the Waikato River and also sits on a shallow (lt;lm to water table) aquifer. In Lesotho, the Maseru landfill is 4 km from a river and 2 km from a water reservoir and rests on a huge aquifer. Over 5000 people depend on groundwater in the area between the landfill and the river. The objectives of my study were to: 1. compare and contrast conditions, management, and potential environmental impacts of the Horotiu and Maseru landfills; 2. evaluate the potential for groundwater contamination as the result of leachate migration; and 3. investigate the chemical characteristics of the landfill leachates and the impacts of the landfills on groundwater quality. The Horotiu study was based on the leachate and groundwater quality monitoring data obtained from the Hamilton City Council. Samples were collected every three months from 1991-2006 and analysed for about 30 chemical parameters. The data for the Maseru landfill consisted of groundwater quality collected by the author during July-September 2007 and borehole pumping data obtained from the Department of Water Affairs, in Lesotho. At Horotiu results indicate that the leachate had high concentrations of: NH4-N (630 mg/l), TOC (405 mg/l), BOD (126 mg/l), and COD (1289 mg/l), while heavy metals were in low concentrations (lt;0.1mg/l). Leachate quality was found to change with time and with rainfall. Groundwater samples obtained from the landfill boreholes indicated that the Horotiu landfill had an influence in the quality of groundwater. Groundwater at the down-slope side of the landfill had higher concentrations of all chemical parameters, except for NO3-N, SO4-2 and Reactive P, than the groundwater on the upstream side. The mean groundwater quality at Horotiu was within New Zealand drinking water standards though some standards were exceeded by some individual samples. In the Maseru landfill, the borehole water had high concentrations of chemical parameters such as EC (1580 μS/cm) and Chloride (190 mg/l), compared to the national average of 250 μS/cm and 28 mg/l. The Maseru landfill groundwater quality was within the WHO drinking water standard for all analysed chemical constituents, except lead. Groundwater beneath both landfills was influenced by leachate but the impacts are currently not at an alarming stage, for analysed chemical parameters. At Maseru introduction of landfill linings has potential to reduce the effect of leachate on groundwater.

This thesis has developed a suite of compound specific stable isotope tools to monitor landfill leachate and identify the infiltration of leachate to ground water and surface water. These tools have the power to indicate the fractional contribution multiple discrete sources of pollution are making to a single location. This journey began by developing two solid phase extraction (SPE) methods to extract non-polar and polar organic compounds from leachate with minimal fractionation of hydrogen or carbon isotopes. Non-polar compounds were successfully extracted using ENV+ SPE cartridges and polar compounds were successfully extracted using Strata-X SPE cartridges. The isotopic fractionation of non-polar compounds during ENV+ extraction varied significantly (up to 245⁰/₀₀ and 1.8⁰/₀₀ for D and ��C respectively, when eluted with acetonitrile and ethyl acetate, as recommended by manufacturers) but the fractionation of compounds eluted with dichloromethane was negligible (less than instrumental precision). Polar compounds were eluted from Strata-X cartridges with negligible isotopic fractionation using methanol. The direct comparison of SPE and liquid-liquid extraction found SPE to extract slightly more compound from leachate then liquid-liquid extraction (especially for polar compounds) and the isotopic compositions of compounds did not change with extraction methods. These new analytical methods subsequently were used to determine the isotopic compositions of organic compounds dissolved in leachates from three New Zealand landfills. The molecular and isotopic signature of leachate varied significantly between landfills, indicating the isotopic fingerprint of organic compounds in leachate is unsuitable as a universal tracer of leachate. However, compounds such as terpien-4-ol, methylethylbenzene and juvabione maintained their isotopic composition over short geographical distance-indicating their potential as site-specific tracers of leachate. Organic compounds analysed on a transect across the landfill boundary indicated polar compounds were more mobile than semi-volatile compounds and possessed a more conservative isotopic composition. However, hexadecanoic acid extracted from leachate and ground water was highly depleted in ��C (-72 ⁰/₀₀ to -40⁰/₀₀), indicative of methanogenic and sulfate reducing bacteria. These bacteria only live in highly reducing environments such as leachate; therefore their presence in the pristine environment can potentially indicate the release of leachate from the landfill. The final experiments traced the uptake and utilisation of leachate by periphyton. The isotopic composition of bulk periphyton, fatty acids and phytol indicated that microbial assimilation and utilisation of nutrients is a complex process. Fatty acid biomarkers for green algae and diatoms showed signs of leachate derived nutrients, however the availability of nutrients (carbon, nitrogen, water and light) caused significant changes in metabolic processes and isotopic compositions. Under slow growing conditions, the [delta]��C composition of periphyton became enriched in ��C as solar irradiation levels decreased (including shading by detritus and periphyton), while the [delta]D composition of fatty acid was controlled by the internal recycling of hydrogen. This study indicated the power of compound specific isotope analysis as a tool to detect the release of landfill leachate from a landfill, especially at locations with multiple potential sources of contaminants, and provides a sound platform for future research.

A study of soil and water samples obtained from Ford's Sanitary Landfill and a control area north of the landfill were investigated for the presence of bacterial pathogens on November 24, 1972, and March 8, 1973. This study revealed the presence of several bacterial pathogens of animal, plant, and human significance in the landfill area. The control area investigated exhibited only normal soil microflora of nonpathogenic significance.Ball State UniversityMuncie, IN 47306