Landfill gas (LFG) contributes significantly to air pollution. Methane (CH4) and carbon dioxide (CO2) are the major constituents of LFG, and are significant greenhouse gases that play a vital role in causing global warming. Certain air pollutants from landfill sites are carcinogenic (e.g. benzene), while others are odorous (e.g. methyl mercaptan). Due to these potential negative impacts, there is need to forecast the yield and production rate of biogas generated. Limited work has been done on the modelling of LFG emissions for landfill sites in Durban. This study focuses on the estimation of air pollutant emissions from three landfill sites, namely Bisasar Road, Shongweni and Buffelsdraai using the LANDGEM model and comparing the results against the findings of Hofstetter Gas Yield Model which has been utilized before by Durban Solid Waste (DSW) for Bisasar Road landfill. The greenhouse gases of global concern, namely CH4, CO2 and halocarbons were investigated in this study. The LANDGEM model predicted CO2 emissions to be higher than CH4 and other greenhouse gases. The warm, moist climatic conditions suitable for CH4 oxidation may be responsible for the increased generation rates of CO2. The main components of LFG which cause landfill odour problems are sulphur-containing compounds. Methyl mercaptan is the component causing persistent bad odours in the landfills, contrary to popular belief that hydrogen sulphide is the major contributor to odour pollution. Hydrogen sulphide has been predicted by LANDGEM to be the sulphur-containing gas that is produced in greatest quantities. Benzene and vinyl chloride are the most hazardous compounds emitted from landfills, since they are carcinogenic. The emission rates of benzene were found to be higher than those of vinyl chloride in the active landfill sites of Bisasar Road and Shongweni. The LANDGEM model estimated total LFG emissions of 8.371 x 107 m3y-1 at Bisasar Road landfill, compared with a lower emission rate of 3.285 x 107 m3y-1 predicted by the Hofstetter model. The LANDGEM model revealed LFG to peak during the closure of the landfill, and to decline thereafter for a long period of time. The Hofstetter model showed that LFG could reach its maximum within three years of waste deposition. LANDGEM model is a widely used methodology for estimating LFG emissions. It is used in United States as regulatory model to quantify the potential LFG emissions produced from the landfill. This model can be used by landfill owners and operators to evaluate the performance of the landfill and to determine whether the landfill is still subject to regulatory requirements, especially in the countries where emission guidelines have been established. Therefore, in the developing country like South Africa, it is essential to quantify and evaluate the LFG emissions released from landfills despite the fact that no legal LFG emission guidelines are put in place yet. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

Populiariausias atliekų valdymo metodas ne tik pasaulyje, bet ir Lietuvoje vis dar išlieka atliekų deponavimas sąvartynuose. Lietuvoje, 2009 metų duomenimis, sąvartynuose buvo pašalinta 90,6 % atliekų. Šiame darbe trumpai aptariama atliekų sąvartynų įrengimo, bei sąvartyno lauko uždengimo tvarka ir rekomendacijos. Aptariami keturiuose uždarytuose Kauno rajono sąvartynuose (Digrių, Gaižėnėlių, Miškinių ir Ilgakiemio) atlikti uždengiamojo sluoksnio būklės tyrimai. Remiantis gautais tyrimų duomenimis daromos išvados apie sąvartynų būklę. Gauti rezultatai rodo, jog ne visi sąvartynai rekultivuojami laikantis taisyklių ir rekomendacijų. Kadangi pastaraisiais dešimtmečiais labai susirūpinta švarios aplinkos išsaugojimu, ekologija ir aplinkos taršos mažinimu, aktualus klausimas išlieka tinkamas atliekų tvarkymas, sąvartynų tinklo optimizavimas (taip pat visiškas jų atsisakymas, dėl valstybių politikos kitaip tvarkyti atliekas, pavyzdžiui, jas deginant), Lietuvoje svarbus klausimas yra senų ir nebenaudojamų savartynų uždarymas. Reikia pasirinkti tinkamą sąvartyno uždarymo būdą, kadangi blogai rekultivuotas sąvartynas, gali sukelti didelę ekologinę katastrofą. / The most popular method of waste management not only in the world, but also in Lithuania, remains depositing waste in landfills. In Lithuania (according to the 2009 data) 90.6% of waste was deposited at the landfills. This work discusses the installation of the landfill, the procedures and recommendations of creating the final landfill covers. There was performed a research on four closed landfills in Kaunas district (Digriai, Gaižėnėliai, Miškiniai and Ilgakiemis) to find out the condition of landfill’s cover layer. According to the findings, conclusions about the condition of these landfills are made. The results show that not all landfills undergo recultivation in accordance with the rules and guidelines. Preservation of the clean environment, ecology and reduction of the environmental pollution is the major concern for the last decades and the most relevant question remains the proper waste management, optimization of the landfill network (as well as the complete abandonment of the landfills, because of different waste management policies, such as incineration). Still, Lithuania has to deal with old and disused landfills, so the proper way to close the landfill must be chosen, because poorly recultivated landfill can cause large ecological catastrophe.

This project examines a sanitary landfill's potential for end-use development. The main purpose is to demonstrate that landfills that have been sited and operated without the development of an end-use plan will have much less end-use potential than those landfills that were sited with an end-use as a major objective.The project consists of three basic stages, introduction, background, and case study. The introduction outlines the project, stating the purpose, the limitations and assumptions, and goals and methods. The background section presents basic information pertaining to solid wastes management and planning, landfill siting and design, and end-use considerations. The case study presents an analysis of the Madison County Landfill in an attempt to demonstrate the end-use potential, or lack of potential, as a recreation facility. In addition to these three sections, there is also an evaluation of the project and a summary and conclusions. / Department of Landscape Architecture

With sufficient time, a high density polyethylene geomembrane will degrade and lose its engineering properties until ruptures signal the end of its service-life. This thesis examines the longevity of nine different geomembranes; five of them were of different thickness manufactured from the same resin. The degradation of properties and time to failure are investigated for geomembranes: in immersion tests; as a part of a landfill composite liner; and, exposed to the elements. The different thermal and stress histories associated with manufacturing geomembranes of different thickness are shown to affect their morphological structure; consequently, their stress crack resistance. When immersed in synthetic leachate, it was found that: (a) thicker geomembranes have a longer antioxidants depletion time but the effect of thickness decreases with temperature and is less than expected; (b) inferences of geomembrane’s longevity based on its initial properties may be misleading because a geomembrane may chemically degrade (as manifested by the change in melt index) despite the presence of a significant amount of stabilizers (as manifested by the measured high pressure oxidative induction time); and, (c) stress crack resistance may change before antioxidant depletion or chemical degradation takes place, likely, due to changes in geomembrane morphological structure with the maximum decrease being observed at 55oC. Reductions also were measured for geomembrane immersed in air and water at 55oC. The geomembrane aged in a simulated landfill liner at 85oC is shown to have service-life as little as three years with 30,000 to >2.0 million ruptures/hectare at failure. For exposed geomembranes in Alumbrera (Argentina), samples were exhumed from two mine facilities after ~16 years of exposure. The antioxidants in exposed samples depleted to residual and the stress crack resistance had dropped to as low as 70 hours. Samples were exhumed from a different exposed geomembrane in a test site in Godfrey (Canada) after six years of exposure. The antioxidants were partially depleted, with depletion to residual projected to take at least 20 years; however, despite no evidence of chemical ageing, the stress crack resistance had decreased from 330 to 190 hours, likely due to changes in the morphological structure of the geomembrane. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2014-02-28 04:59:20.834

Dagens stora materialanvändning är påfrestande för jordens naturresurser. En möjlig källa för framtida resurser är deponier; i avfallet som tidigare deponerats finns ofta såväl återvinningsbara metaller som avfall passande för energiåtervinning. Konceptet landfill mining (LFM) är ett sätt att utnyttja de resurser som finns i deponier och innebär att deponierna grävs ut med efterföljande material- och energiåtervinning.En deponi där landfill mining skulle kunna vara aktuellt är Filbornadeponin i Helsingborg. Tre avsnitt av Filbornadeponin anses vara extra intressanta för en eventuell utgrävning; Lagringsytan, BCR1 och Rökille. Detta examensarbete är en förstudie inför framtida LFM-projekt på Filbornadeponin och syftet är att identifiera kritiska faktorer för projektens genomförande. I arbetet ingår att ta fram materialsammansättningen för aktuella deponier samt en utredning av de ekonomiska och miljömässiga förutsättningarna för respektive projekt.Arbetet är fallstudieinspirerat med målet att kartlägga förutsättningarna för respektive deponi. Detta uppnås via en bakgrundsstudie för respektive deponi, där faktorer som deponivolym, avfallets ålder, materialsammansättning och metangasproduktion undersöks. Bakgrundsstudien kompletteras av en fältstudie där provgrävningar/provborrning, plockanalys och kemisk analys bidrar med mer information. För att genomföra de ekonomiska och miljömässiga beräkningarna ställs två scenarier upp för respektive deponi, ett referensfall där verksamheten fortgår som idag och ett landfill mining-scenario med utgrävning och efterföljande behandling enligt deponiernas specifika förutsättningar.De ekonomiska resultaten visar att två av tre deponier får en större kostnad för LFM-scenariot än för en fortsatt verksamhet liknande den idag. Samtidigt visar de miljömässiga resultaten att stora miljövinster finns kopplade till en utgrävning av de två deponierna Lagringsytan och BCR1. Vid en utgrävning av dessa kan utsläpp av stora mängder metanekvivalenter förhindras. Miljöresultaten för en utgrävning av Rökille uppvisar istället en försämrad miljöprestanda jämfört med referensfallet.Baserat på resultatet har främst sex stycken kritiska faktorer för lönsamhet och miljöprestanda påvisats: (1) Det är svårt att hitta tillgänglig data om en deponis materialsammansättning på förhand och den information som finns är ofta osäker. (2) Ett LFM-projekt kan förhindra framtida metanutsläpp. Dock finns risken att inbunden metangas förekommer i massorna, vilken kan frigöras vid utgrävningen. (3) Det krävs specifik utformning av separationsprocessen och lämplig teknik framtagen särskilt för landfill mining finns inte på marknaden i dagsläget. (4) Lagstiftningen inom området är oklar och ett flertal bestämmelser motverkar resursåtervinningen av gamla deponier. Exempelvis kan riktvärden för metallinnehåll och deponiskatt påverka utfallet för en utgrävning. (5) Metaller är i dagsläget de enda inkomstbringande materialfraktionerna i ett LFM-projekt. Dessutom ger återvinningen av metaller utsläppsbesparingar i form av undvikna utsläpp från jungfruliga metaller. (6) Kostnaden för att skicka bränslefraktionen till förbränning är den enskilt största kostnadsposten i LFM-scenarierna för de två deponierna med en brännbar fraktion. Samtidigt leder förbränningen till utsläpp av fossil koldioxid eftersom en stor del av det brännbara materialet utgörs av plast. / The extensive material use in today's society is demanding for the Earth's natural resources. A possible source for future resources is landfills; the landfills often contain both recyclable metals and other waste fractions suitable for energy recovery. The concept landfill mining (LFM) is a way to exploit the resources found in landfills. In a LFM-project the landfill is excavated with subsequent material and energy recycling.A location where landfill mining could be suitable is the Filborna landfill in Helsingborg. Three sections of the landfill are considered to be especially interesting for a possible excavation; Lagringsytan, BCR1, and Rökille. This thesis is a pilot study for future LFM-projects on Filborna with the aim to identify critical factors for the projects’ implementation. It includes retrieving the material composition of the landfills and an evaluation of the economic and environmental performance of each project.The method is a case study-approach with the goal to identify the specific conditions for each landfill. This is achieved by a background study for each landfill, where factors such as landfill volume, age, material composition, and methane production are examined. The background study complements through a field study where excavation/exploration drilling, picking analysis, and chemical analysis provide extended information. In order to perform the economic and environmental calculations, two scenarios are set up for each landfill; a reference case with business as usual and a LFM-scenario with excavation and subsequent treatment according to the specific landfill conditions.The financial calculations show that two out of three projects have a greater cost connected to the LFM-scenario than for the business as usual scenario. Regarding the environmental performance, the LFM-processes at the landfills Lagringsytan and BCR1 result in a reduction of greenhouse gas emissions compared to the reference case. On the contrary, the results show that the gypsym landfill Rökille yields more greenhouse gas emissions in the LFM-scenario.Based on the results, six critical factors for profitability and environmental performance are identified: (1) It is difficult to find data on a landfill’s material composition in advance and the information available is often uncertain. (2) A landfill mining project can prevent future methane emissions. However, it is possible that methane hidden in the landfill is released during excavation. (3) LFM requires a specific design of the separation process and suitable technology developed specifically for landfill mining is not available on the market today. (4) The law on this area is unclear and several regulations discourage resource recycling of old landfills. For example the limits for metal content and landfill taxation affect the outcome of an excavation. (5) Metals are the only material fractions generating an income in today’s LFM-projects. In addition, the recycling of metals leads to avoided emissions from virgin metals. (6) The cost of sending the fuel fraction to combustion is the largest single cost item in the LFM-scenarios for the two landfills with combustible waste. Also, the combustion causes emissions of fossil carbon dioxide due to the waste’s high plastic content.

The bioreactor landfill is an emerging concept for solid waste management that has gained significant attention in the last decade. This technology employs specific operational practices to enhance the microbial decomposition processes in landfills. However, the unsupervised management and lack of operational guidelines for the bioreactor landfill, specifically leachate manipulation and recirculation processes, usually results in less than optimal system performance. Therefore, these limitations have led to the development of SMART (Sensor-based Monitoring and Remote-control Technology), an expert control system that utilizes real-time monitoring of key system parameters in the management of bioreactor landfills. SMART replaces conventional open-loop control with a feedback control system that aids the human operator in making decisions and managing complex control issues. The target from this control system is to provide optimum conditions for the biodegradation of the refuse, and also, to enhance the performance of the bioreactor in terms of biogas generation. SMART includes multiple cascading logic controllers and mathematical calculations through which the quantity and quality of the recirculated solution are determined. The expert system computes the required quantities of leachate, buffer, supplemental water, and nutritional amendments in order to provide the bioreactor landfill microbial consortia with their optimum growth requirements. Soft computational methods, particularly fuzzy logic, were incorporated in the logic controllers of SMART so as to accommodate the uncertainty, complexity, and nonlinearity of the bioreactor landfill processes. Fuzzy logic was used to solve complex operational issues in the control program of SMART including: (1) identify the current operational phase of the bioreactor landfill based on quantifiable parameters of the leachate generated and biogas produced, (2) evaluate the toxicological status of the leachate based on certain parameters that directly contribute to or indirectly indicates bacterial inhibition, and (3) predict biogas generation rates based on the operational phase, leachate recirculation, and sludge addition. The later fuzzy logic model was upgraded to a hybrid model that employed the learning algorithm of artificial neural networks to optimize the model parameters. SMART was applied to a pilot-scale bioreactor landfill prototype that incorporated the hardware components (sensors, communication devices, and control elements) and the software components (user interface and control program) of the system. During a one-year monitoring period, the feasibility and effectiveness of the SMART system were evaluated in terms of multiple leachate, biogas, and waste parameters. In addition, leachate heating was evaluated as a potential temperature control tool in bioreactor landfills. The pilot-scale implementation of SMART demonstrated the applicability of the system. SMART led to a significant improvement in the overall performance of the BL in terms of methane production and leachate stabilization. Temperature control via recirculation of heated leachate achieved high degradation rates of organic matter and improved the methanogenic activity.

One of the serious and growing potential problems in most large urban areas is the shortage of land for waste disposal. Although there are some efforts to reduce and recover the waste, disposal in landfills is still the most common method for waste destination. An inappropriate landfill site may have negative environmental, economic and ecological impacts. Therefore, it should be selected carefully by considering both regulations and constraints on other sources. In this study, candidate sites for an appropriate landfill area in the vicinity of Ankara are determined by using the integration of Geographic Information Systems and Multicriteria Decision Analysis. For this purpose, sixteen input map layers including topography, settlements (urban centers and villages), roads (Highway E90 and village roads), railways, airport, wetlands, infrastructures (pipelines and power lines), slope, geology, land use, floodplains, aquifers and surface water are prepared and two different MCDA methods (Simple Additive Weighting and Analytic Hierarchy Process) are implemented in GIS environment. Comparison of the maps produced by these two different methods shows that both methods yield conformable results. Field checks also confirm that the candidate sites agree well with the selected criteria.

The purpose of this report is to increase the awareness about the problem that occur when the waste hierarchy is applied to management of contaminated land. The work with remediation of contaminated land in Sweden is part of the efforts towards reaching the national environmental objectives. Therefore a subsidiary aim is to analyze how this influences the prospects of reaching the objectives. The work consists of two parts; a case study and a comparative literature study that focus on England, the Netherlands and Sweden. The case study is intended to provide a practical perspective through a comparison of the climate impact from two methods. One of the methods does not take into account the waste hierarchy and the other is considered, by the principal, to do so. The calculation has been translated to carbon dioxide equivalents through the tool Carbon footprint from the Swedish Geotechnical Society. The literature study has focused on the national legislation connected to contaminated land within the respective countries with the purpose to see how they work with this and identify potential lessons that can be drawn from this comparison. A problem that is made visible through this study is that the waste hierarchy is not sufficiently implemented in the instruments used in Sweden. Landfill tax contribution to the compliance of the waste hierarchy is in the current situation, regarding contaminated soil, nonexistent. But the results of the literature study shows that there is potential for using landfill tax to implement the waste hierarchy in an efficient way. Lessons can be drawn from England, which has increased the accuracy of their landfill tax with two rates, depending on the waste type, and the fact that they have reversed their earlier exemption for contaminated soil. An experience from the case study is that there is a problem within the terminology connected to remediation and waste management in Sweden. The companies and the authorities do not agree about significant terms, for example the reuse and recycling of contaminated soil. This causes problems because the dissidence concerns the options under the hierarchy that should be prioritized.The case study shows that the climate impact from a remediation project can vary substantially between different methods. It would be more efficient if other environmental objectives such as reduced climate impact could be given more weigh in the method selection process than it does in the present situation. This would minimize the risks that a project has a negative impact on the work towards other environmental targets.

Thesis (M. Env. St.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1993. / Includes bibliographical references (leaves 142-161).

Thesis (M. Sc.)--University of Hong Kong, 1995. / Includes bibliographical references (leaves 107-112).