Showing papers on "Bioreactor landfill published in 2005"

The Fate of Nitrogen in Bioreactor Landfills

Abstract: Although bioreactor landfills have many advantages associated with them, challenges remain, including the persistence of ammonia-nitrogen in the leachate. It has been suggested that ammonia-nitrogen is one of the most significant long-term pollution problem in landfills and is likely a parameter that will determine when landfill postclosure monitoring may end. The fate of nitrogen in bioreactor landfills is not well understood. As more landfills transition operation to bioreactors, more attention must be paid to how operating the landfill as a bioreactor may affect the fate of nitrogen. Processes such as sorption, volatilization, nitrification, denitrification, anaerobic ammonium oxidation, and dissimilatory nitrate reduction may all occur.

Evaluating leachate contamination potential of landfill sites using leachate pollution index

Abstract: The dumping of solid waste in uncontrolled landfills can cause significant impacts on the environment and human health. The principal concern is focussed on the pollution potential due to migration of the leachate generated from the landfill sites into the groundwater, the surface water or the sea. In this paper, the concept of the leachate pollution index, a tool for quantifying the leachate pollution potential of landfill sites, has been described and its practical application has been demonstrated by comparing the leachate contamination potential of two active and two closed landfills sites in Hong Kong. It has been found that the leachate generated from the closed landfills can have equal or more contamination potential in comparison to the active landfill sites and hence, the remediation actions and post-closure monitoring should be ensured at the closed landfills till the leachate generated is stabilized and poses no further threat to the environment.

Leachate Recirculation Using Horizontal Trenches in Bioreactor Landfills

Abstract: Leachate recirculation in municipal solid waste (MSW) landfills operated as bioreactors offers significant economical and environmental benefits. Subsurface leachate recirculation in MSW landfills is commonly achieved by using horizontal trenches or vertical wells. Currently, there are no design guidelines available for leachate recirculation using a subsurface leachate recirculation system (LRS). The key objective of this study is to prepare design guidelines for LRS consisting of horizontal trenches. This paper presents a numerical study of LRS consisting of horizontal trenches. The design parameters evaluated in this study include: (1) Leachate injection pressure head; (2) hydraulic conductivity of trench backfill and MSW; (3) dimensions of trench; and (4) spacing and geometric formation of trenches. The finite-element saturated/unsaturated flow model HYDRUS-2D was used for the numerical study. The hydraulic performance of the LRS was evaluated primarily using the simulated recirculated leachate flux a...

The impact of Mpererwe landfill in Kampala–Uganda, on the surrounding environment

Abstract: Mpererwe landfill site receives solid wastes from the city of Kampala, Uganda. This study was carried out to assess and evaluate the appropriateness of the location and operation of this landfill, to determine the composition of the solid waste dumped at the landfill and the extent of contamination of landfill leachate to the neighbouring environment (water, soil and plants). Field observations and laboratory measurements were carried out to determine the concentration of nutrients, metals and numbers of bacteriological indicators in the landfill leachate. The landfill is not well located as it is close to a residential area (

Bioreactor landfills: state-of-the-art review

Abstract: ديمرتلاو فيلوتلاو ريودتلا ةداعإ تايلمع ديازت نم مغرلا ىلع ) دامر ىلإ ليوحتلا ( ةيحصلا نفادملا لازت لاف ، يتلا راكفلأا دحأ يويحلا لعافلا وذ تايافنلا نفدم دعيو ،ةبلصلا تلاضفلا نم صلختلل دئاسلا ليدبلا يه تايافنلل اهيلإ غلابلا هابتنلاا تتفل . ملل يئيبلا ماظنلا نمف ةمئلاملا فورظلل ىلثملا تاجردلا يخوت متي ،يويحلا لعافملا وذ نفد ىرخأ تلايدعت يأب مايقلا وأ ةبرتلا ةلاسغ ةفاضإب تلاضفلل يويحلا للاحنلال . تابث عيرست متي هنإف ،كلذل ةجيتنو تلاضفلا . سايق براجتو ةيربتخملا براجتلا نم ديدعلا ءارجإ مت ،ةيضاملا اماع نيثلاثلا للاخو ةداملا للحت ريثأتو يويحلا للاحنلاا تايلمعو ليوحتلا تلادعمو ،ةيوضعلا تلاضفلا للحت نيسحت ل وح ةدئارلا تاساردلاو تايافنلا نفادم يف تايلمعلا . يئيبلا ماظنلاب تايللآاو يويحلا للاحنلاا تايلمعل اضارعتسا هذه ثحبلا ةقرو مدقتو ا نفادم يف قبطت يتلا تاينقتلاو نفادملل نفادملا نم ةيعونلا هذه ريوطتو ةيويحلا تلاعافملا تاذ تايافنل . Despite increases in recycling, composting, and incineration, the sanitary landfill is still the predominant municipal solid waste disposal alternative. Today, “Bioreactor Landfill” is one idea that has gained significant attention. In the bioreactor landfill ecosystem, the conditions suitable for waste biodegradation are optimized by the addition of leachate or other amendments. As a result, the stabilization of wastes is accelerated. During the past 30 years, numerous laboratory experiments, lysimeter experiments, pilot-scale studies, and full-scale investigations have been done on enhancing organic waste decomposition, conversion rates and process effectiveness in landfills. This paper provides a review of the biodegradation processes and the mechanisms in landfill ecosystem, technologies applied in bioreactor landfills, and the development of the bioreactor landfill.

The Effect of Landfill Leachate Irrigation on Soil Gas Composition: Methane Oxidation and Nitrous Oxide Formation

Abstract: The treatment of landfill leachate by irrigation of the recultivation layer of landfills sites might interfere with greenhouse gas cycling in the soil through alteration of the microbial methane oxidation capacity and promotion of nitrous oxide formation. The interaction of landfill leachate irrigation, methane oxidation and nitrous oxide formation was investigated in a compost – gravel recultivation substrate with and without landfill gas fumigation during a two year lysimeter experiment. Microbial methane oxidation started 3 days after landfill gas addition, and it was promoted by less than 150 mm of landfill leachate application. While long term landfill leachate irrigation negatively affected methane oxidation corresponding to the increasing soil moisture content. In respect to nitrous oxide, formation was low under landfill gas fumigation, while landfill leachate application triggered nitrous oxide production. Only low amounts (< 200 mm) might avoid increasing greenhouse gas concentrations in landfill leachate irrigated soil.

Past, present, and future of MSW landfills in Japan

Abstract: This article focuses on the historical development of landfill technology since the beginning of the nineteenth century in Japan. The regulations and guidelines that form a framework for the technology are reviewed, and the historical background and the current state of Japanese municipal solid waste (MSW) management are described. Through the analysis of data collected from facility leaflets, changes in the leachate treatment system are surveyed. Finally, the concept of the “sustainable bioreactor landfill with low organics” is proposed.

Investigation of water flow in a bioreactor landfill using geoelectrical imaging techniques

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Characteristics of Wastes, Leachate, and Gas at Landfills Operated in Arid Climate

Abstract: A total of 14 liquid waste samples were collected from different sources at all five landfill sites and from disposal containers in Kuwait representing a model of arid countries. Al-Sulaybiya landfill (operating) and Al-Qurain landfill (closed) sites were selected for performing detailed investigation for leachate characteristics. Furthermore, Landfill gas samples were collected from ten boreholes at Al-Qurain landfill for the analysis of gas content ( C H4 and C O2 ) and flow rates. Municipal solid waste (MSW) landfills in Kuwait receive various types of liquid and solid wastes. The results obtained revealed that liquid waste and sludge disposal is the prime cause of large quantity of leachate generation in MSW landfills. The characteristics of leachate generated reflect the nature of liquid waste and sludges disposed in the landfill. The chemical analysis of liquid waste shows that all wastes have high-suspended solids and chemical oxygen demand concentrations. The MSW dumped in the landfill also contai...

Waste Containment and Remediation

Abstract: Proceedings of Geo-Frontiers 2005, held in Austin, Texas, January 24-26, 2005. Sponsored by the Geo-Institute of ASCE. This Geotechnical Special Publication contains 54 papers that address waste containment and remediation. Also included are updates for several technologies that have evolved significantly in the past decade since the publication of Geoenvironment 2000, such as bioreactor landfills and evapotranspiration final cover systems.

Facultative Landfill Bioreactors (FLB): Results of a Pilot-Scale Study

Abstract: This article presents results for the research conducted by the University of New Orleans in which three pilot-plant scale lysimeters were used in a comparative evaluation of the effect of recirculating treated and untreated leachate on waste stabilization rates. Three lysimeters were filled with waste prepared with identical composition. One was operated as a facultative landfill bioreactor (FLB) with external leachate pre-treatment prior to recirculation; the second was operated as anaerobic landfill bioreactor (ALB) with straight raw leachate recirculation; and the third one was the control unit and operated as a conventional (dry) landfill. A leachate treatment plant composed of an electrocoagulation/settling unit and two fluidized bed reactors (FBRs) in series was used in conjunction with the FLB lysimeter. In this article the results presented by de Abreu (2003) regarding organic matter stabilization, nitrogen management, stabilization phases, gas composition, leachate production, and waste compressibility in the three lysimeters are analyzed, showing that the Facultative Landfill Bioreactor is a promising technology for waste treatment and disposal.

Bioreactor Landfills - An Innovative Technology for Biostabilization of Municipal Solid Waste

Abstract: The bioreactor landfill is a concept that has recently attracted interest, especially in North America. In contrast to conventional “dry tomb” landfills, bioreactor landfills provide favourable conditions for microbes to biologically stabilize waste within a relatively short period of time. This is mainly achieved by leachate recirculation, introduction of additional moisture and enhancing other factors that promote bioactivity. Advantages of bioreactor landfills, such as increased landfill gas generation providing opportunities for energy recovery, leachate treatment, potential for air space recovery, greenhouse gas emission reduction, and reduced post-closure monitoring costs, have sparked more interest among solid waste management personnel. The City of Calgary sustainable landfill bio-cell (LBC) is a modified version of a bioreactor landfill. The LBC project is a full-scale pilot study fully funded by the City of Calgary Waste & Recycling Services Business Unit. It is designed to be operated under sequential anaerobic-aerobic conditions to incorporate advantages of both anaerobic and aerobic biodegradation. The development of the LBC provides the City of Calgary with a sustainable solid waste management option.

Leachate recirculation and potential concerns on landfill stabiity

Abstract: Many landfills around the United States are now allowed to recirculate leachate in a controlled manner. Various benefits and problems with leachate recirculation have been observed and reported in the literature. One of the potential issues with leachate recirculation is that slope stability could be reduced by over saturation of the waste. This paper presents a sensitivity analysis on the potential for slope stability failures due to elevated leachate levels within the waste mass. Several practical design and operational recommendations are suggested to help manage these issues.

Laboratory Investigation of TDR System to Monitor MSW Landfill Settlements

Abstract: Settlement in municipal solid waste (MSW) is an important factor affecting landfill management, whether the landfill is operated as a conventional or bioreactor landfill . Mechanical settlement results from compression and consolidation caused by the weight of the waste. Biological settlement occurs following det erioration and subsequent volume loss due to corrosion, oxidation, combustion and decay. Bioreactor landfill technology aims to optimize biological settlement through controlled leachate recirculation. Settlement measurements can allow managers to better estimate waste degradation rates, locate "hot" and "cold" spots, and increase bioreactor efficiency by directing leachate to low -settlement zones. This paper reviews past and current efforts to monitor MSW landfill settlements and presents a new method for monitoring settlement in landfills. Time domain reflectometry (TDR) is a technique utilized to locate and quantify physical changes along a transmission line, such as a coaxial cable, by tracking voltage reflections. While the TDR technique does not work well when cables are pulled in direct tension, it has been shown that prescribing loops along a cable significantly enhances the sensitivity of TDR measurements in tension. When cables are stretched such that the loop radius progressively decreases, v oltage reflection amplitude increases as the loop kinks at its apex. The proposed method was evaluated experimentally in a settlement tank filled with a simulated daily cover composed of a moist paper-sand mixture. The tank is a steel frame structure with tempered glass sheets as sidewalls for visual observation of waste settlement along the boundaries. A galvanized steel plate centered at the base of the tank can be lowered to create a subsidence zone. A series of experiments were performed using singl e-loop and multi-looped cables embedded in the waste and monitored as the plate is lowered. The results show that loops located within the subsidence zone compress as the waste settles, and that the magnitude of voltage reflection increases as the waste c ontinues to settle. Thus the method has the potential to detect and monitor local settlement in MSW landfills.

Nitrogen removal from landfill leachate using single or combined processes.

Abstract: The municipal solids waste (MSW) collected at Shanghai includes a high proportion of food waste, which is easily hydrolyzed to generate ammonia-nitrogen in leachate. This study investigated the efficiency of nitrogen removal from landfill leachate employing four different treatment processes. The simulated rainfall and direct leachate recycling produced strong leachate with high ammonia-nitrogen content, and resulted in the removal of only a small amount of nitrogen. Although pretreating the leachate using an aerobic reactor removed some nitrogen, most of which was transformed to biomass because of the high organic loading applied. Using the three-compartment system, which comprises a landfill column with fresh MSW, a column with well-decomposed refuse layer as the methane generator, and a nitrifier, the ammonia-nitrogen was converted into nitrogen gas and hence removed. Experimental results demonstrated the feasibility of adopting the three-compartment system for managing nitrogen in landfill leachate generated from high-nitrogen-content MSW.

Effects of Leachate Irrigation on Landfill Vegetation and Cover Soil Qualities

Abstract: Vegetation on cover soils, as recommended to protect cover soil from erosion, can be affected by leachate re-circulation employed for treating leachate or accelerating gas production in landfill. In this study, three tropical grasses were investigated for their tolerance to landfill leachate, The potted grasses in pots were irrigated with leachate at different concentrations. It appeared that all plant species were severely damaged when high concentration of leachate was applied. High electrical conductivity in leachate was not the major factor causing plant damage but high organic contents did affect their survival. Nevertheless, the irrigation of leachate at optimum concentration stimulated the growths of some plant species. The lysimeter study confirmed that two landfill gas exposed plants irrigated with leachate at a concentration of 1,770mgCOD.L -1 and hydraulic application rate of 0.57cm.d -1 were growing faster than the plants irrigated with rainwater. Improvement of soil qualities from additional nutrients gained from leachate was observed. This study suggests that the selection of appropriate grass species and provision of optimum organic loading rate should be considered in order to prevent the damage of landfill vegetation when leachate irrigation is practiced in the landfill.

Emission of non CO2 greenhouse gases from landfills of different age located in central Italy

Abstract: Landfill gas is a product of the natural biological decomposition of organic material contained in wastes deposited in landfills. This denomination generically indicates a gas mixture made of methane and carbon dioxide. These gases are produced until most of the organic material in the waste has been degraded. Emissions from municipal landfill sites are therefore potentially harmful to both local and global air quality; the global emissions of an important greenhouse gas such as methane are estimated to be between 20 and 70 Tg year−1. Moreover, landfills have been shown to be a major source of anthropogenic halogenated greenhouse gases such as chlorofluorocarbons (CFCs) and their hydrogenated substitutes (HCFCs, HFCs). These long-living gases are emitted into the atmosphere as a consequence of leakage occurring in landfills where chlorine containing equipment and materials have been dumped. In this study, municipal landfills of different ages located in Tuscany (central Italy) have been investiga...

Effects of leachate recirculation on landfill gas production

Abstract: Based on the typical MSW composition in Shanghai, lab-scale simulated landfill columns were used to study the effects of different leachate recirculation operations on landfill gas (LFG) production. Fresh leachate, pretreated leachate (anaerobic process or aerobic process), and leachate mixture (fresh leachate and leachate from a well-decomposed landfill) were recirculated to landfill columns respectively. The results indicated that the recirculation of leachate without any pretreatment inhibited methane fermentation, while the recirculation of leachate pretreated to some extent benefited to methane fermentation, in that it greatly improved the gas production rate, cumulative gas production Q_t, the ratio of Q_(eff)/Q_t (above 0.80, Q_(eff) means production of gas with methane concentration over 50%), and the ratio of Q_t/Q_p (above 0.40, Q_p means theoretic gas production), as well as shortened the gas production period into near one year. Different leachate pretreatment leaded to different effects, the descending sequence of effectiveness was anaerobic process, mixing with leachate with well-decomposed landfill, and aerobic process. Different leachate pretreatment processes and their treatment level were regarded to influence the methane fermentation and the amount of organic matter disposed ex situ, thus changing the production and quality of LFG.

New Idea on Treatment of Leachate from Municipal Solid Wastes—Application of Bioreactor Landfill Technology

Abstract: To solve the problem of expensive cost and complicated process of treating leachate from municipal solid wastes,simulating landfill experiments were conducted based on analyzing the characteristics of leachate treated by containment landfills and bioreactor landfills.The results indicate that the elimination ratios of COD(chemical oxygen demand) and NH_3-N in leachate from semi-aerobic bioreactor landfills reach up to 95% and 98% respectively.This shows a strong treatment function of bioreactor landfills,and this function can be used to lighten the great pressure of leachate treatment.The research provides a new idea and pathway for the treatment and pollution control of leachate from municipal solid waste landfills.

Dynamic variation of landfill gas production under different landfill treatment

Abstract: Based on the landfill principles, large scale installations of anaerobic and semi-aerobic landfills were established, with the concentrations of CH4, O2 and CO2 detected regularly. The results showed that the average CH4 concentration in semi-aerobic and anaerobic landfill installations was 7%-13% and 35%-50%, respectively, indicating the better effect of semi-aerobic landfill in reducing CH4 production. The CH4 and O2 concentrations in the two landfill installations all presented obvious spatial layer effect, i.e., under-layer > middle layer > upper layer for CH4, while upper layer > middle level > under-layer for O2.

Biochemical Lignin Related Processes in Landfills

Abstract: The objective of this study was to determine how the key features of bioreactor landfills; increased temperature, moisture and microbial activity, affect the biological stability of the landfill material. In the first part of the study the solubilization and degradation of lignin in paper exposed to these bioreactor landfill conditions are explored. The solubility of the lignin in paper was observed at different temperatures and over 27 weeks at 55°C and the anaerobic bioconversion of office paper, cardboard and Kraft lignin was observed in bench-scale reactors over 8 weeks. As the temperature rose, lignin solubility increased exponentially. With extended thermal treatment, the dissolution of lignin continues at a constant rate. This rate increases 15 times for paper and 1.5 times for cardboard in the presence of rumen inoculum compared to uninoculated systems. At around 6 weeks the inter-monomeric linkages between the solubilized lignin molecules began breaking down, releasing monomers. In cardboard and Kraft lignin, a significant amount of the monomers mineralize to CO2 and CH4 during this time period. The results indicate that small, but significant rates of lignin solubilization and anaerobic lignin degradation are likely to occur in bioreactor landfills due to both higher temperature and microbial activity. In the second part of the study, field data from the Outer Loop Recycling and Disposal Facility in Louisville, Kentucky was evaluated to determine the effectiveness of an anaerobic-aerobic landfill bioreactor (AALB) vs. the control landfill that is managed as a traditional landfill. Moisture, temperature, elevation and the amount of time the MSW has spent in the landfills (age) were measured and compared to determine the factors that affect the biological stability of the landfill. The results showed that the MSW in the AALB is more biologically stable than the MSW in the control landfill, indicating that they are more degraded. Additionally, elevation or location of the MSW was the key factor in determining the extent of MSW stability within the AALB and temperature is the key factor in determining the biological stability of the MSW in the control landfill. Higher temperatures correlated with a more biologically stable waste. The cellulose to lignin ratio (C/L ratio) and biochemical methane potential (BMP) were the main biological stability parameters used.