Science.gov

Sample records for landfill gas composition

  1. Temporal variability of soil gas composition in landfill covers.

    PubMed

    Gebert, Julia; Rachor, Ingke; Gröngröft, Alexander; Pfeiffer, Eva-Maria

    2011-05-01

    In order to assess the temporal variability of the conditions for the microbial oxidation of methane in landfill cover soils and their driving variables, gas composition at non-emissive and strongly emissive locations (hotspots) was monitored on a seasonal, daily and hourly time scale on an old, unlined landfill in northern Germany. Our study showed that the impact of the various environmental factors varied with the mode of gas transport and with the time scale considered. At non-emissive sites, governed by diffusive gas transport, soil gas composition was subject to a pronounced seasonal variation. A high extent of aeration, low methane concentrations and a high ratio of CO(2) to CH(4) were found across the entire depth of the soil cover during the warm and dry period, whereas in the cool and moist period aeration was less and landfill gas migrated further upward. Statistically, variation in soil gas composition was best explained by the variation in soil temperature. At locations dominated by advective gas transport and showing considerable emissions of methane, this pattern was far less pronounced with only little increase in the extent of aeration during drier periods. Here, the change of barometric pressure was found to impact soil gas composition. On a daily scale under constant conditions of temperature, gas transport at both types of locations was strongly impacted by the change in soil moisture. On an hourly scale, under constant conditions of temperature and moisture, gas migration was impacted most by the change in barometric pressure. It was shown that at diffusion-dominated sites complete methane oxidation was achieved even under adverse wintry conditions, whereas at hotspots, even under favorable dry and warm conditions, aerobic biological activity can be limited to the upper crust of the soil.

  2. Easy landfill gas profits

    SciTech Connect

    Schleifer, R.

    1988-03-01

    Landfill and digester gases can be valuable fuels. Engine-driven energy recovery systems are a common sight today at landfills and wastewater treatment plants. Yet the complaint is still heard: ''Waste'' gases are tough on engines. That can be true when impurities and variability in landfill or digester gas are not controlled. But with today's fuel-system technology, control is not difficult. Typically, custom-engineered fuel systems for alternate-fuel engine applications can include filters, scrubbers, separators, calorimeters, or other devices needed to deliver an acceptable gas to the engine. It's important that this system is designed only after a thorough gas analysis.

  3. Evaluation Of Landfill Gas Decay Constant For Municipal Solid Waste Landfills Operated As Bioreactors

    EPA Science Inventory

    Prediction of the rate of gas production from bioreactor landfills is important to optimize energy recovery and to estimate greenhouse gas emissions. Landfill gas (LFG) composition and flow rate were monitored for four years for a conventional and two bioreactor landfill landfil...

  4. Landfill gas management in Canada

    SciTech Connect

    David, A.

    1997-12-31

    Landfill gas produced from solid waste landfills is one of the most significant sources of anthropogenic methane in Canada. Methane, a potent greenhouse gas, is 24.5 times more powerful than carbon dioxide by weight in terms of global climate change. Landfill gas recovery plays an important role in Canada`s commitment to stabilize greenhouse gas emissions at 1990 levels by the year 2000 under the United Nations Framework Convention on Climate Change. Landfill gas is a potentially harmful emission that can be converted into a reliable environmentally-sustainable energy source used to generate electricity, fuel industries and heat buildings. The recovery and utilization of landfill gas is a win-win situation which makes good sense from local, regional and global perspectives. It provides the benefits of (1) reducing the release of greenhouse gases that contribute to global warming; (2) limiting odors; (3) controlling damage to vegetation; (4) reducing risks from explosions, fires and asphyxiation; (5) converting a harmful emission into a reliable energy source; and (6) creating a potential source of revenue and profit. Canadian landfills generate about 1 million tons of methane every year; the equivalent energy of 9 million barrels of oil (eight oil super tankers), or enough energy to meet the annual heating needs of more than half a million Canadian homes. Currently, twenty-seven facilities recover and combust roughly 25% of the methane generated by Canadian landfills producing about 3.2 PJ (10{sup 15} Joules) of energy including 80 MW of electricity and direct fuel for nearby facilities (e.g., cement plants, gypsum board manufacturers, recycling facilities, greenhouses). This paper reviews landfill gas characteristics; environmental, health and safety impacts; landfill gas management in Canada; the costs of landfill gas recovery and utilization systems; and on-going projects on landfill gas utilization and flaring.

  5. Landfill gas project. Final report

    SciTech Connect

    1983-01-01

    The methane gas recovered from the landfill is used for space heating and water heating for the Florence-Lauderdale Humane Shelter 600 feet from the well head. The project to date and future development are described briefly. (MHR)

  6. Evaluation of the age of landfill gas methane in landfill gas-natural gas mixtures using co-occurring constituents.

    PubMed

    Kerfoot, Henry B; Hagedorn, Benjamin; Verwiel, Mark

    2013-06-01

    At a municipal solid waste landfill in southern California (USA) overlying a natural gas reservoir, methane was detected at concentrations of up to 40% (by volume) in perimeter soil gas probes. Stable isotope and (14)C values of methane together with gas composition (major components and volatile organic compounds) data were evaluated to assess the relative contributions of landfill gas and natural gas to the measured methane concentrations. The data was further used to estimate the residence time of the landfill gas in the probes. Results showed that up to 37% of the measured methane was derived from landfill gas. In addition, the landfill gas in the probe samples has undergone extensive alteration due to dissolution of carbon dioxide in pore water. Data further indicates that the measured methane was released from the waste approximately 1.2 to 9.4 years ago, rather than representing evidence of an ongoing release.

  7. Sour landfill gas problem solved

    SciTech Connect

    Nagl, G.; Cantrall, R.

    1996-05-01

    In Broward County, Fla., near Pompano Beach, Waste Management of North America (WMNA, a subsidiary of WMX Technologies, Oak Brook, IL) operates the Central Sanitary Landfill and Recycling Center, which includes the country`s largest landfill gas-to-energy plant. The landfill consists of three collection sites: one site is closed, one is currently receiving garbage, and one will open in the future. Approximately 9 million standard cubic feet (scf) per day of landfill gas is collected from approximately 300 wells spread over the 250-acre landfill. With a dramatic increase of sulfur-containing waste coming to a South Florida landfill following Hurricane Andrew, odors related to hydrogen sulfide became a serious problem. However, in a matter of weeks, an innovative desulfurization unit helped calm the landfill operator`s fears. These very high H{sub 2}S concentrations caused severe odor problems in the surrounding residential area, corrosion problems in the compressors, and sulfur dioxide (SO{sub 2}) emission problems in the exhaust gas from the turbine generators.

  8. Landfill Gas Effects on Evapotranspirative Landfill Covers

    NASA Astrophysics Data System (ADS)

    Plummer, M. A.; Mattson, E.; Ankeny, M.; Kelsey, J.

    2005-05-01

    The performance of an evapotranspirative landfill cover can be adversely affected by transport of landfill gases to the plant root zone. Healthy plant communities are critical to the success and effectiveness of these vegetated landfill covers. Poor vegetative cover can result in reduced transpiration, increased percolation, and increased erosion regardless of the thickness of the cover. Visual inspections of landfill covers indicate that vegetation-free areas are not uncommon at municipal waste landfills. Data from soil profiles beneath these areas suggest that anaerobic conditions in the plant-rooting zone are controlling plant distribution. On the same landfill, aerobic conditions exist at similar depths beneath well-vegetated areas. The movement of methane and carbon dioxide, generated by degradation of organic wastes, into the overlying soil cover displaces oxygen in the root zone. Monitoring data from landfills in semi-arid areas indicate that barometric pumping can result in hours of anaerobic conditions in the root zone. Microbial consumption of oxygen in the root zone reduces the amount of oxygen available for plant root respiration but consumption of oxygen and methane also produce water as a reaction byproduct. This biogenic water production can be on the order of centimeters of water per year which, while increasing water availability, also has a negative feedback on transport of landfill gases through the cover. Accounting for these processes can improve evapotranspirative landfill cover design at other sites.

  9. Mathematical modelling of landfill gas migration in MSW sanitary landfills.

    PubMed

    Martín, S; Marañón, E; Sastre, H

    2001-10-01

    The laws that govern the displacement of landfill gas in a sanitary landfill are analysed. Subsequently, a 2-D finite difference flow model of a fluid in a steady state in a porous medium with infinite sources of landfill gas is proposed. The fact that landfill gas is continuously generated throughout the entire mass of the landfill differentiates this model from others extensively described in the literature and used in a variety of different applications, such as oil recovery, groundwater flow, etc. Preliminary results are then presented of the application of the model. Finally, the results obtained employing data from the literature and experimental assays carried out at the La Zoreda sanitary landfill (Asturias, Spain) are discussed and future lines of research are proposed.

  10. Landfill gas cleanup for fuel cells

    SciTech Connect

    1995-08-01

    EPRI is to test the feasibility of using a carbonate fuel cell to generate electricity from landfill gas. Landfills produce a substantial quantity of methane gas, a natural by-product of decaying organic wastes. Landfill gas, however, contains sulfur and halogen compounds, which are known contaminants to fuel cells and their fuel processing equipment. The objective of this project is to clean the landfill gas well enough to be used by the fuel cell without making the process prohibitively expensive. The cleanup system tested in this effort could also be adapted for use with other fuel cells (e.g., solid oxide, phosphoric acid) running on landfill gas.

  11. Demonstration of landfill gas enhancement techniques in landfill simulators

    NASA Astrophysics Data System (ADS)

    Walsh, J. J.; Vogt, W. G.

    1982-02-01

    Various techniques to enhance gas production in sanitary landfills were applied to landfill simulators. These techniques include (1) accelerated moisture addition, (2) leachate recycling, (3) buffer addition, (4) nutrient addition, and (5) combinations of the above. Results are compiled through on-going operation and monitoring of sixteen landfill simulators. These test cells contain about 380 kg of municipal solid waste. Quantities of buffer and nutrient materials were placed in selected cells at the time of loading. Water is added to all test cells on a monthly basis; leachate is withdrawn from all cells (and recycled on selected cells) also on a monthly basis. Daily monitoring of gas volumes and refuse temperatures is performed. Gas and leachate samples are collected and analyzed on a monthly basis. Leachate and gas quality and quantity reslts are presented for the first 18 months of operation.

  12. LANDFILL GAS PRETREATMENT FOR FUEL CELL APPLICATIONS

    EPA Science Inventory

    The paper discusses the U.S. EPA's program, underway at International Fuel Cells Corporation, to demonstrate landfill methane control and the fuel cell energy recovery concept. In this program, two critical issues are being addressed: (1) a landfill gas cleanup method that would ...

  13. Landfill gas recovery: An analysis of results

    NASA Astrophysics Data System (ADS)

    Peterson, J. M.

    1982-02-01

    Aspects of landfill gas recovery including the range of gas recovery, production rates, corrosion, medium-Btu industrial applications, and conversion to electricity via an internal combustion engine were investigated. It is estimated that the landfill site studied is capable of producing more than 2.17 x 10 to the 13th power Btu's of gas per year for a period of over eight years.

  14. How landfill gas causes RCRA compliance problems

    SciTech Connect

    Kerfoot, H.B.

    1996-06-01

    The Resource Conservation and Recovery Act (RCRA) requires landfill operators to monitor groundwater at their facilities. This regulatory requirement is designed to prevent contamination that can result as rainfall drains through refuse, causing pollutants to leach into the groundwater. Several parameters commonly associated with leachate are monitored under RCRA as indicator parameters, or parameters that represent readily detected indicators of contamination. These parameters include volatile organic compounds (VOCs) and alkalinity. Because of its potentially high concentration of VOCs and non-volatile contaminants, landfill leachate represents the greatest threat to groundwater from solid waste facilities. However, other sources can elevate indicator parameters as well. Increasingly lower detection limits can be achieved for VOCs in groundwater, enabling detection of VOCs and carbon dioxide (CO{sub 2}) from landfill gas. In addition, CO{sub 2} from landfill gas can increase groundwater alkalinity. Releases of VOCs in landfill gas can be eliminated by minimizing the gas pressure within the landfill, either by installing a gas-collection system or upgrading an existing gas-collection system by adding wells or altering gas flow in portions of the system.

  15. Operating a fuel cell using landfill gas

    SciTech Connect

    Trippel, C.E.; Preston, J.L. Jr.; Trocciola, J.; Spiegel, R.

    1996-12-31

    An ONSI PC25{trademark}, 200 kW (nominal capacity) phosphoric acid fuel cell operating on landfill gas is installed at the Town of Groton Flanders Road landfill in Groton, Connecticut. This joint project by the Connecticut Light & Power Company (CL&P) which is an operating company of Northeast Utilities, the Town of Groton, International Fuel Cells (IFC), and the US EPA is intended to demonstrate the viability of installing, operating and maintaining a fuel cell operating on landfill gas at a landfill site. The goals of the project are to evaluate the fuel cell and gas pretreatment unit operation, test modifications to simplify the GPU design and demonstrate reliability of the entire system.

  16. Effects of landfill gas on subtropical woody plants

    NASA Astrophysics Data System (ADS)

    Chan, G. Y. S.; Wong, M. H.; Whitton, B. A.

    1991-05-01

    An account is given of the influence of landfill gas on tree growth in the field at Gin Drinkers' Bay (GDB) landfill, Hong Kong, and in the laboratory. Ten species ( Acacia confusa, Albizzia lebbek, Aporusa chinensis, Bombax malabaricum, Castanopsis fissa, Liquidambar formosana, Litsea glutinosa, Machilus breviflora, Pinus elliottii, and Tristania conferta), belonging to eight families, were transplanted to two sites, one with a high concentration of landfill gas in the cover soil (high-gas site, HGS) and the other with a relatively low concentration of gas (low-gas site, LGS). Apart from the gaseous composition, the general soil properties were similar. A strong negative correlation between tree growth and landfill gas concentration was observed. A laboratory study using the simulated landfill gas to fumigate seedlings of the above species showed that the adventitious root growth of Aporusa chinensis, Bombax malabaricum, Machilus breviflora, and Tristania confera was stimulated by the gas, with shallow root systems being induced. Acacia confusa, Albizzia lebbek, and Litsea glutinosa were gas-tolerant, while root growth of Castanopsis fissa, Liquidambar formosana, and Pinus elliottii was inhibited. In most cases, shoot growth was not affected, exceptions being Bombax malabaricum, Liquidambar formosana, and Tristania conferta, where stunted growth and/or reduced foliation was observed. A very high CO2 concentration in cover soil limits the depth of the root system. Trees with a shallow root system become very susceptible to water stress. The effects of low O2 concentration in soil are less important than the effects of high CO2 concentration. Acacia confusa, Albizzia lebbek, and Tristania conferta are suited for growth on subtropical completed landfills mainly due to their gas tolerance and/or drought tolerance.

  17. Landfill gas boosted to pipeline quality

    SciTech Connect

    Not Available

    1984-03-01

    The world's largest landfill recovery facility, located on Staten Island, went on stream in 1982 and is expected to produce 1.3 billion CF/yr of pipeline gas. Containing 45% carbon dioxide, the gas is compressed and cooled in stages to meet the requirements of the Selexol purification plant. Two 1120-kW (1500-hp) Copper Bessemer GMVS-8C integral gas engine-compressors, fueled by the landfill gas, provide the compression needed from the wells to the final solvent-contact stage.

  18. Emergency landfill gas control at the Milwaukee County Landfill

    SciTech Connect

    Michels, M.S.; Boone, D.A.

    1996-11-01

    In October 1994, up to 55 percent methane concentrations by volume were found below 76th Street in Franklin, Wisconsin. Numerous utilities exist below 76th Street which service homes located only 100 feet east. The Milwaukee County Landfill, located immediately west of 76th Street, was the source of methane gas. With winter weather conditions approaching, Milwaukee County was concerned that landfill gas (LFG) could migrate along utilities or in sandy soil and enter basements of adjacent homes. The County declared an emergency to immediately release funds and authorized a design/build contract to remedy the gas migration. CDM Engineers and Constructors, Inc. was selected for the project. The Milwaukee County Department of Public Works, Environmental Services Division led the project team. Numerous activities occurred simultaneously, including: (1) Public Relations, (2) Notification to Wisconsin DNR, (3) Design and Permitting, (4) Ordering the Flare, (5) Installing Methane Detectors in 29 Basements. Public relations included public forums with local residences, monthly newsletters, meetings with the ski hill operator, television interviews, local newspaper interviews, briefing the County Alderman and City of Franklin officials. Cooperation from Wisconsin DNR provided a 10-day turnaround for approval of the design. A perimeter active gas collection and flare system was employed to mitigate LFG. The system included eight gas extraction wells drilled to the base of the landfill and one horizontal trench (approximately 40 feet long). Extraction wells and trench were connected together with a buried 6-inch HDPE header pipe. Condensate is collected in a 550-gallon double-walled steel tank.

  19. Passive drainage and biofiltration of landfill gas: Australian field trial

    SciTech Connect

    Dever, S.A. . E-mail: stuart_dever@ghd.com.au; Swarbrick, G.E. . E-mail: g.swarbrick@unsw.edu.au; Stuetz, R.M. . E-mail: r.stuetz@unsw.edu.au

    2007-07-01

    In Australia a significant number of landfill waste disposal sites do not incorporate measures for the collection and treatment of landfill gas. This includes many old/former landfill sites, rural landfill sites, non-putrescible solid waste and inert waste landfill sites, where landfill gas generation is low and it is not commercially viable to extract and beneficially utilize the landfill gas. Previous research has demonstrated that biofiltration has the potential to degrade methane in landfill gas, however, the microbial processes can be affected by many local conditions and factors including moisture content, temperature, nutrient supply, including the availability of oxygen and methane, and the movement of gas (oxygen and methane) to/from the micro-organisms. A field scale trial is being undertaken at a landfill site in Sydney, Australia, to investigate passive drainage and biofiltration of landfill gas as a means of managing landfill gas emissions at low to moderate gas generation landfill sites. The design and construction of the trial is described and the experimental results will provide in-depth knowledge on the application of passive gas drainage and landfill gas biofiltration under Sydney (Australian) conditions, including the performance of recycled materials for the management of landfill gas emissions.

  20. Using landfill gas for energy: Projects that pay

    SciTech Connect

    1995-02-01

    Pending Environmental Protection Agency regulations will require 500 to 700 landfills to control gas emissions resulting from decomposing garbage. Conversion of landfill gas to energy not only meets regulations, but also creates energy and revenue for local governments.

  1. Soil gas investigations at the Sanitary Landfill

    SciTech Connect

    Wyatt, D.E.; Pirkle, R.J.; Masdea, D.J.

    1992-07-01

    A soil gas survey was performed at the 740-G Sanitary Landfill of Savannah River Plant during December, 1990. The survey monitored the presence and distribution of the C[sub 1]C[sub 4] hydrocarbons; the C[sub 5]-C[sub 10] normal paraffins; the aromatic hydrocarbons, BTXE; selected chlorinated hydrocarbons; and mercury. Significant levels of several of these contaminants were found associated with the burial site. In the northern area of the Landfill, methane concentrations ranged up to 63% of the soil gas and were consistently high on the western side of the access road. To the east of the access road in the northern and southern area high concentrations of methane were encountered but were not consistently high. Methane, the species found in highest concentration in the landfill, was generated in the landfill as the result of biological oxidation of cellulose and other organics to carbon dioxide followed by reduction of the carbon dioxide to methane. Distributions of other species are the result of burials in the landfill of solvents or other materials.

  2. Soil gas investigations at the Sanitary Landfill

    SciTech Connect

    Wyatt, D.E.; Pirkle, R.J.; Masdea, D.J.

    1992-07-01

    A soil gas survey was performed at the 740-G Sanitary Landfill of Savannah River Plant during December, 1990. The survey monitored the presence and distribution of the C{sub 1}C{sub 4} hydrocarbons; the C{sub 5}-C{sub 10} normal paraffins; the aromatic hydrocarbons, BTXE; selected chlorinated hydrocarbons; and mercury. Significant levels of several of these contaminants were found associated with the burial site. In the northern area of the Landfill, methane concentrations ranged up to 63% of the soil gas and were consistently high on the western side of the access road. To the east of the access road in the northern and southern area high concentrations of methane were encountered but were not consistently high. Methane, the species found in highest concentration in the landfill, was generated in the landfill as the result of biological oxidation of cellulose and other organics to carbon dioxide followed by reduction of the carbon dioxide to methane. Distributions of other species are the result of burials in the landfill of solvents or other materials.

  3. Partitioning Gas Tracer Technology for Measuring Water in Landfills

    NASA Astrophysics Data System (ADS)

    Briening, M. L.; Jakubowitch, A.; Imhoff, P. T.; Chiu, P. C.; Tittlebaum, M. E.

    2002-12-01

    Unstable landfills can result in significant environmental contamination and can become a risk to public health. To reduce this risk, water may be added to landfills to ensure that enough moisture exists for biodegradation of organic wastes. In this case risks associated with future breaks in the landfill cap are significantly reduced because organic material is degraded more rapidly. To modify moisture conditions and enhance biodegradation, leachate is typically collected from the bottom of the landfill and then recirculated near the top. It is difficult, though, to know how much leachate to add and where to add it to achieve uniform moisture conditions. This situation is exacerbated by the heterogeneous nature of landfill materials, which is known to cause short circuiting of infiltrating water, a process that has been virtually impossible to measure or model. Accurate methods for measuring the amount of water in landfills would be valuable aids for implementing leachate recirculation systems. Current methods for measuring water are inadequate, though, since they provide point measurements and are frequently affected by heterogeneity of the solid waste composition and solid waste compaction. The value of point measurements is significantly reduced in systems where water flows preferentially, such as in landfills. Here, spatially integrated measurements might be of greater value. In this research we are evaluating a promising technology, the partitioning gas tracer test, to measure the water saturation within landfills, the amount of free water in solid waste divided by the volume of the voids. The partitioning gas tracer test was recently developed by researchers working in the vadose zone. In this methodology two gas tracers are injected into a landfill. One tracer is non-reactive with landfill materials, while the second partitions into and out of free water trapped within the pore space of the solid waste. Chromatographic separation of the tracers occurs

  4. FUEL CELL ENERGY RECOVERY FROM LANDFILL GAS

    EPA Science Inventory

    International Fuel Cells Corporation is conducting a US Environmental Protection Agency (EPA) sponsored program to demonstrate energy recovery from landfill gas using a commercial phosphoric acid fuel cell power plant. The US EPA is interested in fuel cells for this application b...

  5. FIRST ORDER KINETIC GAS GENERATION MODEL PARAMETERS FOR WET LANDFILLS

    EPA Science Inventory

    Landfill gas is produced as a result of a sequence of physical, chemical, and biological processes occurring within an anaerobic landfill. Landfill operators, energy recovery project owners, regulators, and energy users need to be able to project the volume of gas produced and re...

  6. FIELD TEST MEASUREMENTS AT FIVE MUNICIPAL SOLID WASTE LANDFILLS WITH LANDFILL GAS CONTROL TECHNOLOGY--FINAL REPORT

    EPA Science Inventory

    Research was conducted to evaluate landfill gas emissions at five municipal solid waste landfills which have modern control technology for landfill gas emissions. Comprehensive testing was conducted on the raw landfill gas and the combustion outlet exhaust. The project had two ...

  7. Methane Gas Utilization Project from Landfill at Ellery (NY)

    SciTech Connect

    Pantelis K. Panteli

    2012-01-10

    Landfill Gas to Electric Energy Generation and Transmission at Chautauqua County Landfill, Town of Ellery, New York. The goal of this project was to create a practical method with which the energy, of the landfill gas produced by the decomposing waste at the Chautauqua County Landfill, could be utilized. This goal was accomplished with the construction of a landfill gas to electric energy plant (originally 6.4MW and now 9.6MW) and the construction of an inter-connection power-line, from the power-plant to the nearest (5.5 miles) power-grid point.

  8. An energy perspective on landfill gas

    SciTech Connect

    Hutchinson, P.J. )

    1993-01-01

    Globally, one billion metric tons of organic waste in the form of municipal solid waste are placed into solid-waste containment facilities every year. Complete biodegradation of this waste can generate approximately 2.8x10[sup 11] m[sup 3] (9.9 trillion cubic feet (Tcf) or 1.98x10[sup 8] metric tons) of biogas. Biogas consists of approximately equal proportions of methane and carbon dioxide; thus a year's worth of waste can potentially generate 1.4x10[sup 11] m[sup 3] (5 Tcf or 9.9x10[sup 7] metric tons) of methane. If we assume that landfill-biogas generation began only 20 years ago and has proceeded at a steady rate, then we can estimate that it can contribute 5x10[sup 10] m[sup 3] (1.8 Tcf or 36x10[sup 6] metric tons) of methane to the global atmospheric budget every year. Landfill gas is difficult to recover and use. Exploitation of biogas includes use as a raw product for heat energy, dehydration to produce electric generator fuel, refinement for commercial transportation, and use as a chemical feedstock. Controlled-reactor landfills, called [open quotes]biofills,[close quotes] are designed for optimum methane generation to ensure a steady and consistent rate of gas generation. Biofill mechanisms used to improve gas production include physical and chemical modifications to the modern landfill design. These methods can reduce the gas-generation time from 80 years to 5 years, can reduce the waste mass, and can reduce negative effects on the environment. 134 refs., 4 figs., 4 tabs.

  9. Landfill gas energy recovery: Turning a liability into an asset

    SciTech Connect

    Nichols, M.

    1996-08-01

    Until the past decade, landfill gas (LFG) was viewed as a nuisance at best and a hazard at worst. Today, municipalities and private-sector solid waste management companies are findings ways to put landfill gas to productive use. Landfill gas energy recovery eliminates detrimental air emissions; prevents landfill methane from contributing to global climate change; stops methane from migrating off-site and becoming a safety hazard or odor problem; and provides local utilities, industry, and consumers with a competitive, local source of power. In other words, LFG-to-energy facilities provide a unique form of recycling--solid waste is hauled to the landfill as refuse and returned to the consumer in the form of energy. US EPA`s Landfill Methane Outreach Program (LMOP) and new EPA regulations for control of landfill gas emissions work together to encourage greater use of LFT at many facilities across the US.

  10. Microbial mitigation of greenhouse gas emissions from landfill cover soils

    NASA Astrophysics Data System (ADS)

    Lee, Sung-Woo

    of pMMO-expressing methanotrophs was observed, suggesting that these methanotrophs were responsible for nitrous oxide production. Collectively, these data demonstrate that methanotrophic activity and community structure can be differentially affected by both landfill gas composition and amendments, thus providing insights as how best to manipulate methanotrophic processes to better mitigate greenhouse gas emissions.

  11. TEST RESULTS FOR FUEL-CELL OPERATION ON LANDFILL GAS

    EPA Science Inventory

    Test results from a demonstration of fuel-cell (FC) energy recovery and control of landfill gas emissions are presented. The project addressed two major issues: (i) the design, construction, and testing of a landfill-gas cleanup system; and (ii) a field test of a commercial phos...

  12. Gaseous methyl- and inorganic mercury in landfill gas from landfills in Florida, Minnesota, Delaware, and California

    NASA Astrophysics Data System (ADS)

    Lindberg, S. E.; Southworth, G.; Prestbo, E. M.; Wallschläger, D.; Bogle, M. A.; Price, J.

    2005-01-01

    Municipal waste landfills contain numerous sources of mercury which could be emitted to the atmosphere. Their generation of methane by anaerobic bacteria suggests that landfills may act as bioreactors for methylated mercury compounds. Since our previous study at a single Florida landfill, gaseous inorganic and methylated mercury species have now been identified and quantified in landfill gas at nine additional municipal landfills in several regions of the US. Total gaseous mercury occurs at concentrations in the μg m-3 range, while methylated compounds occur at concentrations in the ng m-3 range at all but one of the landfill sites. Dimethylmercury is the predominant methylated species, at concentrations up to 100 ng m-3, while monomethyl mercury was generally lower. Limited measurements near sites where waste is exposed for processing (e.g. working face, transfer areas) suggest that dimethylmercury is released during these activities as well. Although increasing amounts of landfill gas generated in the US are flared (which should thermally decompose the organic mercury to inorganic mercury), unflared landfill gas is a potentially important anthropogenic source of methylated mercury emissions to the atmosphere.

  13. Albany Interim Landfill gas extraction and mobile power system: Using landfill gas to produce electricity. Final report

    SciTech Connect

    1997-06-01

    The Albany Interim Landfill Gas Extraction and Mobile Power System project served three research objectives: (1) determination of the general efficiency and radius of influence of horizontally placed landfill gas extraction conduits; (2) determination of cost and effectiveness of a hydrogen sulfide gas scrubber utilizing Enviro-Scrub{trademark} liquid reagent; and (3) construction and evaluation of a dual-fuel (landfill gas/diesel) 100 kW mobile power station. The horizontal gas extraction system was very successful; overall, gas recovery was high and the practical radius of influence of individual extractors was about 50 feet. The hydrogen sulfide scrubber was effective and its use appears feasible at typical hydrogen sulfide concentrations and gas flows. The dual-fuel mobile power station performed dependably and was able to deliver smooth power output under varying load and landfill gas fuel conditions.

  14. Evaluation of Partitioning Gas Tracer Tests for Measuring Water in Landfills

    NASA Astrophysics Data System (ADS)

    Imhoff, P. T.; Han, B.; Jafarpour, Y.; Gallagher, V. N.; Chiu, P. C.; Fluman, D. A.; Vasuki, N. C.; Yazdani, R.; Augenstein, D.; Cohen, K. K.

    2003-12-01

    Methane is an important greenhouse gas, and landfills are the largest anthropogenic source in many developed countries. Bioreactor landfills have been proposed as one means of abating greenhouse gas emissions from landfills. Here, the decomposition of organic wastes is enhanced by the controlled addition of water or leachate to maintain optimal conditions for waste decomposition. Greenhouse gas abatement is accomplished by sequestration of photosynthetically derived carbon in wastes, CO2 offsets from energy use of waste derived gas, and mitigation of methane emission from the wastes. An important issue in the operation of bioreactor landfills is knowing how much water to add and where to add it. Accurate methods for measuring the amount of water in landfills would be valuable aids for implementing leachate recirculation systems. Current methods for measuring water are inadequate, though, since they provide point measurements and are frequently affected by heterogeneity of the solid waste composition and solid waste compaction. The value of point measurements is significantly reduced in systems where water flows preferentially, such as in landfills. Here, spatially integrated measurements might be of greater value. We are evaluating a promising technology, the partitioning gas tracer test, to measure the water saturation within landfills, the amount of free water in solid waste divided by the volume of the voids. The partitioning gas tracer test was recently developed by researchers working in the vadose zone. We report the results from laboratory and field tests designed to evaluate the partitioning gas tracer test within an anaerobic landfill operated by the Delaware Solid Waste Authority. Vertical wells were installed within the landfill to inject and extract tracer gases. Gas flow and tracer gas movement in the solid waste were controlled by the landfill's existing gas collection system, which included vertical wells installed throughout the landfill through

  15. Keeping landfill gas systems in tune

    SciTech Connect

    Blackman, L.; Myers, L.; Bjerkin, L.; Freemon, P.

    1998-01-01

    The efficiency of LFG recovery systems is influenced by many complex and interrelated factors including atmospheric conditions and LFG dynamics. In order to balance the operation of a LFG system, the factors that influence the system, such as the effects of atmospheric conditions must be understood and taken into consideration. The dynamics include: typical, daily diurnal changes in barometric pressure and the temperature and density of the ambient air due to local meteorological conditions; major changes in barometric pressure and the temperature and density of ambient air due to transient high and low pressure systems related to weather conditions; dynamics of the biochemical activity within the landfill; and dynamics of the LFG flowing through the gas extraction system pipe lines. These factors dramatically influence LFG density, mass flow, quantity, and quality. They also influence the ability of a well designed gas collection system to effectively control gas migration and to provide a reasonably high gas product for energy recovery. Thus, an efficient LFG extraction system must attempt to compensate for these varying and uncontrollable conditions.

  16. Estimating methane emissions from landfills based on rainfall, ambient temperature, and waste composition: The CLEEN model.

    PubMed

    Karanjekar, Richa V; Bhatt, Arpita; Altouqui, Said; Jangikhatoonabad, Neda; Durai, Vennila; Sattler, Melanie L; Hossain, M D Sahadat; Chen, Victoria

    2015-12-01

    Accurately estimating landfill methane emissions is important for quantifying a landfill's greenhouse gas emissions and power generation potential. Current models, including LandGEM and IPCC, often greatly simplify treatment of factors like rainfall and ambient temperature, which can substantially impact gas production. The newly developed Capturing Landfill Emissions for Energy Needs (CLEEN) model aims to improve landfill methane generation estimates, but still require inputs that are fairly easy to obtain: waste composition, annual rainfall, and ambient temperature. To develop the model, methane generation was measured from 27 laboratory scale landfill reactors, with varying waste compositions (ranging from 0% to 100%); average rainfall rates of 2, 6, and 12 mm/day; and temperatures of 20, 30, and 37°C, according to a statistical experimental design. Refuse components considered were the major biodegradable wastes, food, paper, yard/wood, and textile, as well as inert inorganic waste. Based on the data collected, a multiple linear regression equation (R(2)=0.75) was developed to predict first-order methane generation rate constant values k as functions of waste composition, annual rainfall, and temperature. Because, laboratory methane generation rates exceed field rates, a second scale-up regression equation for k was developed using actual gas-recovery data from 11 landfills in high-income countries with conventional operation. The Capturing Landfill Emissions for Energy Needs (CLEEN) model was developed by incorporating both regression equations into the first-order decay based model for estimating methane generation rates from landfills. CLEEN model values were compared to actual field data from 6 US landfills, and to estimates from LandGEM and IPCC. For 4 of the 6 cases, CLEEN model estimates were the closest to actual.

  17. Estimating methane emissions from landfills based on rainfall, ambient temperature, and waste composition: The CLEEN model.

    PubMed

    Karanjekar, Richa V; Bhatt, Arpita; Altouqui, Said; Jangikhatoonabad, Neda; Durai, Vennila; Sattler, Melanie L; Hossain, M D Sahadat; Chen, Victoria

    2015-12-01

    Accurately estimating landfill methane emissions is important for quantifying a landfill's greenhouse gas emissions and power generation potential. Current models, including LandGEM and IPCC, often greatly simplify treatment of factors like rainfall and ambient temperature, which can substantially impact gas production. The newly developed Capturing Landfill Emissions for Energy Needs (CLEEN) model aims to improve landfill methane generation estimates, but still require inputs that are fairly easy to obtain: waste composition, annual rainfall, and ambient temperature. To develop the model, methane generation was measured from 27 laboratory scale landfill reactors, with varying waste compositions (ranging from 0% to 100%); average rainfall rates of 2, 6, and 12 mm/day; and temperatures of 20, 30, and 37°C, according to a statistical experimental design. Refuse components considered were the major biodegradable wastes, food, paper, yard/wood, and textile, as well as inert inorganic waste. Based on the data collected, a multiple linear regression equation (R(2)=0.75) was developed to predict first-order methane generation rate constant values k as functions of waste composition, annual rainfall, and temperature. Because, laboratory methane generation rates exceed field rates, a second scale-up regression equation for k was developed using actual gas-recovery data from 11 landfills in high-income countries with conventional operation. The Capturing Landfill Emissions for Energy Needs (CLEEN) model was developed by incorporating both regression equations into the first-order decay based model for estimating methane generation rates from landfills. CLEEN model values were compared to actual field data from 6 US landfills, and to estimates from LandGEM and IPCC. For 4 of the 6 cases, CLEEN model estimates were the closest to actual. PMID:26346020

  18. USERS MANUAL: LANDFILL GAS EMISSIONS MODEL - VERSION 2.0

    EPA Science Inventory

    The document is a user's guide for a computer model, Version 2.0 of the Landfill Gas Emissions Model (LandGEM), for estimating air pollution emissions from municipal solid waste (MSW) landfills. The model can be used to estimate emission rates for methane, carbon dioxide, nonmet...

  19. Analysis of factors affecting methane-gas recovery from six landfills. Final report Jul 90-Jul 91

    SciTech Connect

    Campbell, D.; Epperson, D.; Davis, L.; Peer, R.; Gray, W.

    1991-09-01

    The report gives results of a pilot study of six U.S. landfills that have methane (CH4) gas recovery systems. (NOTE: The study was a first step in developing a field testing program to gather data to identify key variables that affect CH4 generation and to develop an empirical model of CH4 generation based on those variables. The field test program development, in turn, is part of EPA/AEERL's research program aimed at improving global landfill CH4 emissions estimates.) To evaluate the effects of climate on CH4 production and recovery, the six sites represented a variety of moisture and temperature patterns (i.e., hot and wet, cool and wet, hot and dry). Landfill gas was tested at each landfill to evaluate the quality of the gas recovery data available at each. The testing included assessing the adequacy of on-site instrumentation and scanning the landfill surfaces for organic vapors that would indicate emissions of CH4. In addition, information on waste composition and landfill characteristics was sought for each landfill. Except for flow measurements, the test procedures selected were well suited to the types of gas recovery installations encountered at the landfills visited. Based on comparisons between EPA Reference Method 3C and instrument analyses of the landfill gas compositions, all on-site analysis instruments appeared to be operating with reasonable accuracy.

  20. Fuel Flexibility: Landfill Gas Contaminant Mitigation for Power Generation

    SciTech Connect

    Storey, John Morse; Theiss, Timothy J; Kass, Michael D; FINNEY, Charles E A; Lewis, Samuel; Kaul, Brian C; Besmann, Theodore M; Thomas, John F; Rogers, Hiram; Sepaniak, Michael

    2014-04-01

    This research project focused on the mitigation of silica damage to engine-based renewable landfill gas energy systems. Characterization of the landfill gas siloxane contamination, combined with characterization of the silica deposits in engines, led to development of two new mitigation strategies. The first involved a novel method for removing the siloxanes and other heavy contaminants from the landfill gas prior to use by the engines. The second strategy sought to interrupt the formation of hard silica deposits in the engine itself, based on inspection of failed landfill gas engine parts. In addition to mitigation, the project had a third task to develop a robust sensor for siloxanes that could be used to control existing and/or future removal processes.

  1. Feasibility study: utilization of landfill gas for a vehicle fuel system, Rossman's landfill, Clackamas County, Oregon

    SciTech Connect

    1981-01-01

    In 1978, a landfill operator in Oregon became interested in the technical and economic feasibility of recovering the methane generated in the landfill for the refueling of vehicles. DOE awarded a grant for a site-specific feasibility study of this concept. This study investigated the expected methane yield and the development of a conceptual gas-gathering system; gas processing, compressing, and storage systems; and methane-fueled vehicle systems. Cost estimates were made for each area of study. The results of the study are presented. Reasoning that gasoline prices will continue to rise and that approximately 18,000 vehicles in the US have been converted to operate on methane, a project is proposed to use this landfill as a demonstration site to produce and process methane and to fuel a fleet (50 to 400) vehicles with the gas produced in order to obtain performance and economic data on the systems used from gas collection through vehicle operation. (LCL)

  2. EPA`s landfill methane outreach program: Helping facilities save money and protect the environment by using landfill gas

    SciTech Connect

    Walsh, J.

    1997-06-01

    Until the past decade, landfill gas (LFG) was viewed as a nuisance at best and a hazard at worst. Today, many landfill owners and private-sector solid waste management companies are finding ways to put landfill gas to productive use. Landfill gas energy recovery eliminates detrimental air emissions; prevents landfill methane from contributing to global climate change; stops methane from migrating off-site and becoming a safety hazard or odor problem; and provides local utilities, industry, and consumers with a competitive, local source of power. In other words, LFG-to-energy facilities provide a unique form of recycling - solid waste is hauled to the landfill as refuse and returned to the consumer in the form of energy. US EPA`s Landfill Methane Outreach Program (LMOP) works to encourage greater use of LFG at facilities across the US.

  3. Controlled Landfill Project in Yolo County, California for Environmental Benefits of Waste Stabilization and Minimization of Greenhouse Gas Emissions

    NASA Astrophysics Data System (ADS)

    Yazdani, R.; Augenstein, D.; Kieffer, J.; Cohen, K.

    2003-12-01

    The Department of Public Works of Yolo County, California, USA has been testing an advanced approach to landfill bioreactors, controlled (or "enhanced") landfilling, at its Yolo County Central Landfill site near Davis, CA, since 1994. Overall objectives have been the management of waste landfilling for: (1) rapid completion of total gas generation; (2) maximum, high-efficiency gas capture; (3) waste volume reduction; and (4) maximum greenhouse gas and carbon sequestration benefits. Methane generation is controlled and enhanced through carefully managed moisture additions, and by taking advantage of landfill temperature elevation. The generated landfill methane, an important greenhouse gas, is recovered with high efficiency through extraction from a porous recovery layer beneath a surface geomembrane cover. Instrumentation included a total of 56 moisture and 15 temperature sensors in the two cells, gas flow monitoring by positive displacement gas meters, and accurate quantification of liquid inputs and outputs. Gas composition, waste volume reduction, base hydrostatic head, and a range of environmental compliance parameters has been monitored since 1995. Partitioning gas tracer tests using the injection of two gases at dilute concentrations in the landfill have also been initiated to compute the fraction of pore space occupied by water between the points of tracer injection and tracer measurement. There has been rapid waste volume reduction in the enhanced cell that corresponds to the solids' reduction to gas. Monitoring is planned for the next several years, until stabilization parameters are determined complete. Encouraging performance is indicated by: (1) sensor data; (2) gas generation results; (3) data from landfill cores; and (4) decomposition-related indicators including rapid volume reduction. When data are synthesized, project results have attractive implications for new approaches to landfill management. Over seven-years, methane recoveries have averaged

  4. TECHNICAL ASSESSMENT OF FUEL CELL OPERATION ON LANDFILL GAS AT THE GROTON, CT, LANDFILL

    EPA Science Inventory

    The paper summarizes the results from a seminal assessment conducted on a fuel cell technology which generates electrical power from waste landfill gas. This assessment/ demonstration was the second such project conducted by the EPA, the first being conducted at the Penrose Power...

  5. LCA and economic evaluation of landfill leachate and gas technologies.

    PubMed

    Damgaard, Anders; Manfredi, Simone; Merrild, Hanna; Stensøe, Steen; Christensen, Thomas H

    2011-07-01

    Landfills receiving a mix of waste, including organics, have developed dramatically over the last 3-4 decades; from open dumps to engineered facilities with extensive controls on leachate and gas. The conventional municipal landfill will in most climates produce a highly contaminated leachate and a significant amount of landfill gas. Leachate controls may include bottom liners and leachate collection systems as well as leachate treatment prior to discharge to surface water. Gas controls may include oxidizing top covers, gas collection systems with flares or gas utilization systems for production of electricity and heat. The importance of leachate and gas control measures in reducing the overall environmental impact from a conventional landfill was assessed by life-cycle-assessment (LCA). The direct cost for the measures were also estimated providing a basis for assessing which measures are the most cost-effective in reducing the impact from a conventional landfill. This was done by modeling landfills ranging from a simple open dump to highly engineered conventional landfills with energy recovery in form of heat or electricity. The modeling was done in the waste LCA model EASEWASTE. The results showed drastic improvements for most impact categories. Global warming went from an impact of 0.1 person equivalent (PE) for the dump to -0.05 PE for the best design. Similar improvements were found for photochemical ozone formation (0.02 PE to 0.002 PE) and stratospheric ozone formation (0.04 PE to 0.001 PE). For the toxic and spoiled groundwater impact categories the trend is not as clear. The reason for this was that the load to the environment shifted as more technologies were used. For the dump landfill the main impacts were impacts for spoiled groundwater due to lack of leachate collection, 2.3 PE down to 0.4 PE when leachate is collected. However, at the same time, leachate collection causes a slight increase in eco-toxicity and human toxicity via water (0.007 E to 0

  6. LCA and economic evaluation of landfill leachate and gas technologies.

    PubMed

    Damgaard, Anders; Manfredi, Simone; Merrild, Hanna; Stensøe, Steen; Christensen, Thomas H

    2011-07-01

    Landfills receiving a mix of waste, including organics, have developed dramatically over the last 3-4 decades; from open dumps to engineered facilities with extensive controls on leachate and gas. The conventional municipal landfill will in most climates produce a highly contaminated leachate and a significant amount of landfill gas. Leachate controls may include bottom liners and leachate collection systems as well as leachate treatment prior to discharge to surface water. Gas controls may include oxidizing top covers, gas collection systems with flares or gas utilization systems for production of electricity and heat. The importance of leachate and gas control measures in reducing the overall environmental impact from a conventional landfill was assessed by life-cycle-assessment (LCA). The direct cost for the measures were also estimated providing a basis for assessing which measures are the most cost-effective in reducing the impact from a conventional landfill. This was done by modeling landfills ranging from a simple open dump to highly engineered conventional landfills with energy recovery in form of heat or electricity. The modeling was done in the waste LCA model EASEWASTE. The results showed drastic improvements for most impact categories. Global warming went from an impact of 0.1 person equivalent (PE) for the dump to -0.05 PE for the best design. Similar improvements were found for photochemical ozone formation (0.02 PE to 0.002 PE) and stratospheric ozone formation (0.04 PE to 0.001 PE). For the toxic and spoiled groundwater impact categories the trend is not as clear. The reason for this was that the load to the environment shifted as more technologies were used. For the dump landfill the main impacts were impacts for spoiled groundwater due to lack of leachate collection, 2.3 PE down to 0.4 PE when leachate is collected. However, at the same time, leachate collection causes a slight increase in eco-toxicity and human toxicity via water (0.007 E to 0

  7. Economic and environmental benefits of landfill gas utilisation in Oman.

    PubMed

    Abushammala, Mohammed Fm; Qazi, Wajeeha A; Azam, Mohammed-Hasham; Mehmood, Umais A; Al-Mufragi, Ghithaa A; Alrawahi, Noor-Alhuda

    2016-08-01

    Municipal solid waste disposed in landfill sites decomposes under anaerobic conditions and produces so-called landfill-gas, which contains 30%-40% of carbon dioxide (CO2) and 50%-60% of methane (CH4). Methane has the potential of causing global warming 25 times more than CO2 Therefore, migration of landfill-gas from landfills to the surrounding environment can potentially affect human life and environment. Thus, this research aims to determine municipal solid waste generation in Oman over the years 1971-2030, to quantify annual CH4 emissions inventory that resulted from this waste over the same period of time, and to determine the economic and environmental benefits of capturing the CH4 gas for energy production. It is found that cumulative municipal solid waste landfilled in Oman reaches 3089 Giga gram (Gg) in the year 2030, of which approximately 85 Gg of CH4 emissions are produced in the year 2030. The study also found that capturing CH4 emissions between the years 2016 and 2030 could attract revenues of up to US$333 million and US$291 million from the carbon reduction and electricity generation, simultaneously. It is concluded that CH4 emissions from solid waste in Oman increases enormously with time, and capture of this gas for energy production could provide a sustainable waste management solution in Oman.

  8. 40 CFR Table Hh-3 to Subpart Hh of... - Landfill Gas Collection Efficiencies

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Landfill Gas Collection Efficiencies... (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills Pt. 98, Subpt. HH, Table HH-3 Table HH-3 to Subpart HH of Part 98—Landfill Gas Collection...

  9. 40 CFR Table Hh-3 to Subpart Hh of... - Landfill Gas Collection Efficiencies

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Landfill Gas Collection Efficiencies... (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills Pt. 98, Subpt. HH, Table HH-3 Table HH-3 to Subpart HH of Part 98—Landfill Gas Collection...

  10. 40 CFR Table Hh-3 to Subpart Hh of... - Landfill Gas Collection Efficiencies

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Landfill Gas Collection Efficiencies... (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills Pt. 98, Subpt. HH, Table HH-3 Table HH-3 to Subpart HH of Part 98—Landfill Gas Collection...

  11. 40 CFR Table Hh-3 to Subpart Hh of... - Landfill Gas Collection Efficiencies

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Landfill Gas Collection Efficiencies... (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills Pt. 98, Subpt. HH, Table HH-3 Table HH-3 to Subpart HH of Part 98—Landfill Gas Collection...

  12. LIQUID NATURAL GAS (LNG): AN ALTERNATIVE FUEL FROM LANDFILL GAS (LFG) AND WASTEWATER DIGESTER GAS

    SciTech Connect

    VANDOR,D.

    1999-03-01

    This Research and Development Subcontract sought to find economic, technical and policy links between methane recovery at landfill and wastewater treatment sites in New York and Maryland, and ways to use that methane as an alternative fuel--compressed natural gas (CNG) or liquid natural gas (LNG) -- in centrally fueled Alternative Fueled Vehicles (AFVs).

  13. EMERGING TECHNOLOGIES FOR THE MANAGEMENT AND UTILIZATION OF LANDFILL GAS

    EPA Science Inventory

    The report gives information on emerging technologies that are considered to be commercially available (Tier 1), currently undergoing research and development (Tier 2), or considered as potentially applicable (Tier 3) for the management of landfill gas (LFG) emissions or for the ...

  14. FUEL CELL OPERATION ON LANDFILL GAS AT PENROSE POWER STATION

    EPA Science Inventory

    This demonstration test successfully demonstrated operation of a commercial phosphoric acid fuel cell (FC) on landfill gas (LG) at the Penrose Power Station in Sun Valley, CA. Demonstration output included operation up to 137 kW; 37.1% efficiency at 120 kW; exceptionally low sec...

  15. Feasibility study for utilization of landfill gas at the Royalton Road Landfill, Broadview Heights, Ohio. Final report

    SciTech Connect

    1983-09-01

    The technical viability of landfill gas recovery has been previously demonstrated at numerous sites. However, the economics of a full scale utilization system are dependent on proper market conditions, appropriate technologies, landfill gas quantity and quality, and public/purchaser acceptance. The specific objectives of this feasibility study were to determine: The available markets which might purchase landfill gas or landfill gas derived energy products; An extraction system concept design and to perform an on-site pumping test program; The landfill gas utilization technologies most appropriate for the site; Any adverse environmental, health, safety, or socioeconomic impacts associated with the various proposed technologies; The optimum project economics, based on markets and processes examined. Findings and recommendations were presented which review the feasibility of a landfill gas utilization facility on the Royalton Road Landfill. The three identified utilization alternatives are indeed technically feasible. However, current market considerations indicate that installation of a full scale system is not economically advisable at this time. This final report encompasses work performed by SCS Engineers from late 1980 to the present. Monitoring data from several extraction and monitoring wells is presented, including pumping rates and gas quality and quantity analysis. The Market Analysis Data Form, local climatological data, and barometric pressure data are included in the appendix section. 33 figures, 25 tables.

  16. Effectiveness of compacted soil liner as a gas barrier layer in the landfill final cover system.

    PubMed

    Moon, Seheum; Nam, Kyoungphile; Kim, Jae Young; Hwan, Shim Kyu; Chung, Moonkyung

    2008-01-01

    A compacted soil liner (CSL) has been widely used as a single barrier layer or a part of composite barrier layer in the landfill final cover system to prevent water infiltration into solid wastes for its acceptable hydraulic permeability. This study was conducted to test whether the CSL was also effective in prohibiting landfill gas emissions. For this purpose, three different compaction methods (i.e., reduced, standard, and modified Proctor methods) were used to prepare the soil specimens, with nitrogen as gas, and with water and heptane as liquid permeants. Measured gas permeability ranged from 2.03 x 10(-10) to 4.96 x 10(-9) cm(2), which was a magnitude of two or three orders greater than hydraulic permeability (9.60 x 10(-13) to 1.05 x 10(-11) cm(2)). The difference between gas and hydraulic permeabilities can be explained by gas slippage, which makes gas more permeable, and by soil-water interaction, which impedes water flow and then makes water less permeable. This explanation was also supported by the result that a liquid permeability measured with heptane as a non-polar liquid was similar to the intrinsic gas permeability. The data demonstrate that hydraulic requirement for the CSL is not enough to control the gas emissions from a landfill. PMID:17964132

  17. Effectiveness of compacted soil liner as a gas barrier layer in the landfill final cover system.

    PubMed

    Moon, Seheum; Nam, Kyoungphile; Kim, Jae Young; Hwan, Shim Kyu; Chung, Moonkyung

    2008-01-01

    A compacted soil liner (CSL) has been widely used as a single barrier layer or a part of composite barrier layer in the landfill final cover system to prevent water infiltration into solid wastes for its acceptable hydraulic permeability. This study was conducted to test whether the CSL was also effective in prohibiting landfill gas emissions. For this purpose, three different compaction methods (i.e., reduced, standard, and modified Proctor methods) were used to prepare the soil specimens, with nitrogen as gas, and with water and heptane as liquid permeants. Measured gas permeability ranged from 2.03 x 10(-10) to 4.96 x 10(-9) cm(2), which was a magnitude of two or three orders greater than hydraulic permeability (9.60 x 10(-13) to 1.05 x 10(-11) cm(2)). The difference between gas and hydraulic permeabilities can be explained by gas slippage, which makes gas more permeable, and by soil-water interaction, which impedes water flow and then makes water less permeable. This explanation was also supported by the result that a liquid permeability measured with heptane as a non-polar liquid was similar to the intrinsic gas permeability. The data demonstrate that hydraulic requirement for the CSL is not enough to control the gas emissions from a landfill.

  18. Hazard ranking of landfills using fuzzy composite programming

    SciTech Connect

    Hagemeister, M.E.; Jones, D.D.; Woldt, W.E.

    1996-04-01

    The environmental and health risks posed by unregulated landfills are concerns that must be addressed. These concerns have been highlighted with the recent reauthorization of the Resource Conservation and Recovery Act (RCRA) Subtitle D, which requires the closure of all unregulated landfills by October 1993. Most communities with unregulated landfills do not have the financial resources to conduct full-scale risk assessments. This paper proposes the use of a multicriteria assessment system as a tool for screening and prioritizing unregulated disposal sites according to their level of environmental and health hazard. This multicriteria assessment system uses a technique termed composite programming and allows for the use of imprecise information through fuzzy set theory. Using this methodology in landfill hazard assessment allows for the consideration of uncertainty associated with parameters that impact the hazard assessment. Additionally, the user can specify hazards that are most detrimental. The complexity of input parameters (first level indicators) were selected to minimize the time required to collect and/or analyze site-specific data. The result obtained in the assessment is a fuzzy number that indicates the most likely range of hazard and the largest likely range of hazard relative to the best and worst case scenarios. A case study, in which this method is applied to a small rural landfill, is presented to illustrate the methodology.

  19. Forecasting the settlement of a bioreactor landfill based on gas pressure changes.

    PubMed

    Qiu, Gang; Li, Liang; Sun, Hongjun

    2013-10-01

    In order to study the influence of settlement under gas pressure in bioreactor landfill, the landfill is simplified as a one-way gas seepage field, combining Darcy's Law, the gas equation of state, and the principle of effective stress and fluid dynamics of porous media theory. First assume that the bioreactor landfill leachate is fully recharged on the basis of gas mass conservation, then according to the changes in gas pressure (inside the landfill and surrounding atmosphere) during the gas leakage time and settlement in the landfill, establish a numerical model of bioreactor landfill settlement under the action of the gas pressure, and use the finite difference method to solve it. Through a case study, the model's improved prediction of the settlement of bioreactor landfill is demonstrated.

  20. Forecasting the settlement of a bioreactor landfill based on gas pressure changes.

    PubMed

    Qiu, Gang; Li, Liang; Sun, Hongjun

    2013-10-01

    In order to study the influence of settlement under gas pressure in bioreactor landfill, the landfill is simplified as a one-way gas seepage field, combining Darcy's Law, the gas equation of state, and the principle of effective stress and fluid dynamics of porous media theory. First assume that the bioreactor landfill leachate is fully recharged on the basis of gas mass conservation, then according to the changes in gas pressure (inside the landfill and surrounding atmosphere) during the gas leakage time and settlement in the landfill, establish a numerical model of bioreactor landfill settlement under the action of the gas pressure, and use the finite difference method to solve it. Through a case study, the model's improved prediction of the settlement of bioreactor landfill is demonstrated. PMID:23771879

  1. U.S. EPA'S RESEARCH TO UPDATE GUIDANCE FOR QUANTIFYING LANDFILL GAS EMISSIONS

    EPA Science Inventory

    Landfill emissions, if left uncontrolled, contribute to air toxics, climate change, tropospheric ozone, and urban smog. EPA's Office of Research and Development is conducting research to help update EPA's landfill gas emission factors. The last update to EPA's landfill gas emiss...

  2. Siloxane removal from landfill and digester gas - a technology overview.

    PubMed

    Ajhar, M; Travesset, M; Yüce, S; Melin, T

    2010-05-01

    This paper reviews technologies for the removal of volatile methyl siloxanes (VMS) from biogas. More than 20 years after identifying silicon dioxide in gas engines running on landfill and sewage gas, three technologies are commercially available to remove siloxanes today: adsorption, absorption and deep chilling. Newer concepts based on technologies other than sorption or condensation have not yet gained access to commercial biogas purification. These emerging siloxane removal concepts include biotrickling filters, catalysts, membranes, and in the case of sewage gas, sludge stripping, peroxidation and filtration at point inlet source. This work introduces the main principles of commercial siloxane removal systems and reviews scientific progress in the field over the last decade.

  3. Remote Real-Time Monitoring of Subsurface Landfill Gas Migration

    PubMed Central

    Fay, Cormac; Doherty, Aiden R.; Beirne, Stephen; Collins, Fiachra; Foley, Colum; Healy, John; Kiernan, Breda M.; Lee, Hyowon; Maher, Damien; Orpen, Dylan; Phelan, Thomas; Qiu, Zhengwei; Zhang, Kirk; Gurrin, Cathal; Corcoran, Brian; O’Connor, Noel E.; Smeaton, Alan F.; Diamond, Dermot

    2011-01-01

    The cost of monitoring greenhouse gas emissions from landfill sites is of major concern for regulatory authorities. The current monitoring procedure is recognised as labour intensive, requiring agency inspectors to physically travel to perimeter borehole wells in rough terrain and manually measure gas concentration levels with expensive hand-held instrumentation. In this article we present a cost-effective and efficient system for remotely monitoring landfill subsurface migration of methane and carbon dioxide concentration levels. Based purely on an autonomous sensing architecture, the proposed sensing platform was capable of performing complex analytical measurements in situ and successfully communicating the data remotely to a cloud database. A web tool was developed to present the sensed data to relevant stakeholders. We report our experiences in deploying such an approach in the field over a period of approximately 16 months. PMID:22163975

  4. Remote real-time monitoring of subsurface landfill gas migration.

    PubMed

    Fay, Cormac; Doherty, Aiden R; Beirne, Stephen; Collins, Fiachra; Foley, Colum; Healy, John; Kiernan, Breda M; Lee, Hyowon; Maher, Damien; Orpen, Dylan; Phelan, Thomas; Qiu, Zhengwei; Zhang, Kirk; Gurrin, Cathal; Corcoran, Brian; O'Connor, Noel E; Smeaton, Alan F; Diamond, Dermot

    2011-01-01

    The cost of monitoring greenhouse gas emissions from landfill sites is of major concern for regulatory authorities. The current monitoring procedure is recognised as labour intensive, requiring agency inspectors to physically travel to perimeter borehole wells in rough terrain and manually measure gas concentration levels with expensive hand-held instrumentation. In this article we present a cost-effective and efficient system for remotely monitoring landfill subsurface migration of methane and carbon dioxide concentration levels. Based purely on an autonomous sensing architecture, the proposed sensing platform was capable of performing complex analytical measurements in situ and successfully communicating the data remotely to a cloud database. A web tool was developed to present the sensed data to relevant stakeholders. We report our experiences in deploying such an approach in the field over a period of approximately 16 months. PMID:22163975

  5. Response of tomato plants to simulated landfill gas mixtures

    SciTech Connect

    Arthur, J.J.; Leone, I.A.; Flower, F.B.

    1985-01-01

    The roots of tomato plants were fumigated with simulated refuse-generated gas mixtures at levels of methane (CH/sub 4/), carbon dioxide (CO/sub 2/), and oxygen (O/sub 2/) previously measured in the atmospheres of landfill cover soils associated with poor growth or death of plants. A concentration of 18% CO/sub 2/ or greater, exceeded in almost 30% of thirty-two landfills examined throughout the US, caused reduced growth and visible symptoms on tomato after 1 wk, regardless of O/sub 2/ level. Doubling the CO/sub 2/ level to that encountered in a typical local site (Edgeboro Landfill) resulted in more severe symptom development and the subsequent death of plants. Methane, in concentrations of 20% and above, found in more than 25% of the landfills visited, while not observed to be toxic per se; was associated with drastic O/sub 2/ depletion in the soil atmosphere, which activity was believed to be the cause of the plant decline.

  6. Landfill gas and its influence on global climate change. Book chapter

    SciTech Connect

    Thorneloe, S.A.

    1993-01-01

    The report describes the relative importance of landfills to global warming and identifies the major sources of uncertainty with current emission estimates. It also provides an overview of EPA's research program on global landfill methane, including developing more reliable estimates of global landfill methane emissions, characterizing the current state of technology for controlling and utilizing landfill methane, and demonstrating innovative technologies for mitigating and utilizing landfill methane. Landfills are considered a major source of methane, which is a potent greenhouse gas. Because this source is amenable to cost effective control measures, research designed to reduce the uncertainty associated with methane emissions estimates has been given high priority.

  7. Passive landfill gas emission - Influence of atmospheric pressure and implications for the operation of methane-oxidising biofilters.

    PubMed

    Gebert, Julia; Groengroeft, Alexander

    2006-01-01

    A passively vented landfill site in Northern Germany was monitored for gas emission dynamics through high resolution measurements of landfill gas pressure, flow rate and composition as well as atmospheric pressure and temperature. Landfill gas emission could be directly related to atmospheric pressure changes on all scales as induced by the autooscillation of air, diurnal variations and the passage of pressure highs and lows. Gas flux reversed every 20 h on average, with 50% of emission phases lasting only 10h or less. During gas emission phases, methane loads fed to a connected methane oxidising biofiltration unit varied between near zero and 247 g CH4 h(-1)m(-3) filter material. Emission dynamics not only influenced the amount of methane fed to the biofilter but also the establishment of gas composition profiles within the biofilter, thus being of high relevance for biofilter operation. The duration of the gas emission phase emerged as most significant variable for the distribution of landfill gas components within the biofilter.

  8. Effect of enhanced leachate recirculated (ELR) landfill operation and gas extraction on greenhouse gas emissions

    NASA Astrophysics Data System (ADS)

    Samir, Sonia

    The bioreactor/ enhanced leachate recirculated (ELR) landfill operation with the addition of moisture/ leachate to the landfill, accelerate the process of landfill waste decomposition; and increase the generation of LFG over a shorter period of time. Since emissions from the landfills are directly related to the gas generation, the increase in gas generation might also increase the emission from the landfill. On the contrary, the presence of gas extraction is suggested to mitigate the fugitive emissions from the landfills. Therefore, the motivation of the current study was to evaluate the effect of ELR operation as well as the gas extraction on the greenhouse gas emissions from the landfill. The current study was conducted in the City of Denton Landfill, Texas. Methane emission was investigated using a portable FID and static flux chamber technique from the landfill surface. Emission was measured from an ELR operated cell (cell 2) as well as a conventional cell (cell 0) in the City of Denton Landfill. Methane emission for cell 2 varied from 9544.3 ppm to 0 ppm while for cell 0, it varied from 0 ppm to 47 ppm. High spatial variations were observed during monitoring from both cells 0 and cell 2 which could be recognized as the variation of gas generation below the cover soil. The comparison between emissions from the slope and surface of the landfill showed that more methane emission occurred from the slopes than the top surface. In addition, the average landfill emission showed an increasing trend with increase in temperature and decreasing trend with increasing precipitation. The effect of ELR operation near the recirculation pipes showed a lag period between the recirculation and the maximum emission near the pipe. The emission near the pipe decreased after 1 day of recirculation and after the initial decrease, the emission started to increase and continued to increase up to 7 days after the recirculation. However, approximately after 10 days of recirculation, the

  9. Estimating methane gas generation from Devil's swamp landfill using greenhouse gas emission models

    NASA Astrophysics Data System (ADS)

    Adeyemi, Ayodeji Thompson

    Greenhouse gas (GHG) has been a key issue in the study, design, and management of landfills. Landfill gas (LFG) is considered either as a significant source of renewable energy (if extracted and processed accordingly) or significant source of pollution and risk (if not mitigated or processed). A municipal solid waste (MSW) landfill emits a significant amount of methane, a potent GHG. Thus, quantification and mitigation of GHG emissions is an important area of study in engineering and other sciences related to landfill technology and management. The present study will focus on estimating methane generation from Devils swamp landfill (DSLF), a closed landfill in Baton Rouge, LA. The landfill operated for 53 years (1940-1993) and contains both industrial and municipal waste products. Since the Clean Air Act of 1963, landfills are now classified as New Source Performance Standard (NSPS) waste (i.e., waste that will decompose to generate LFG). Currently, the DSLF is being used as source of renewable energy through the "Waste to Energy" program. For this study, to estimate the methane potential in the DSLF, it is important to determine the characteristics and classification of the landfill's wastes. The study uses and compares different GHG modeling tools---LandGEM, a multiphase model, and a simple first-order model---to estimate methane gas emission and compare results with the actual emissions from the DSLF. The sensitivity of the methane generation rate was analyzed by the methane generation models to assess the effects of variables such as initial conditions, specific growth rate, and reaction rate constants. The study concludes that methane (L0) and initial organic concentration in waste (k) are the most important parameters when estimating methane generation using the models.

  10. The impact of landfilling and composting on greenhouse gas emissions--a review.

    PubMed

    Lou, X F; Nair, J

    2009-08-01

    Municipal solid waste is a significant contributor to greenhouse gas emissions through decomposition and life-cycle activities processes. The majority of these emissions are a result of landfilling, which remains the primary waste disposal strategy internationally. As a result, countries have been incorporating alternative forms of waste management strategies such as energy recovery from landfill gas capture, aerobic landfilling (aerox landfills), pre-composting of waste prior to landfilling, landfill capping and composting of the organic fraction of municipal solid waste. As the changing global climate has been one of the major environmental challenges facing the world today, there is an increasing need to understand the impact of waste management on greenhouse gas emissions. This review paper serves to provide an overview on the impact of landfilling (and its various alternatives) and composting on greenhouse gas emissions taking into account streamlined life cycle activities and the decomposition process. The review suggests greenhouse gas emissions from waste decomposition are considerably higher for landfills than composting. However, mixed results were found for greenhouse gas emissions for landfill and composting operational activities. Nonetheless, in general, net greenhouse gas emissions for landfills tend to be higher than that for composting facilities.

  11. A decision support tool for landfill methane generation and gas collection.

    PubMed

    Emkes, Harriet; Coulon, Frédéric; Wagland, Stuart

    2015-09-01

    This study presents a decision support tool (DST) to enhance methane generation at individual landfill sites. To date there is no such tool available to provide landfill decision makers with clear and simplified information to evaluate biochemical processes within a landfill site, to assess performance of gas production and to identify potential remedies to any issues. The current lack in understanding stems from the complexity of the landfill waste degradation process. Two scoring sets for landfill gas production performance are calculated with the tool: (1) methane output score which measures the deviation of the actual methane output rate at each site which the prediction generated by the first order decay model LandGEM; and (2) landfill gas indicators' score, which measures the deviation of the landfill gas indicators from their ideal ranges for optimal methane generation conditions. Landfill gas indicators include moisture content, temperature, alkalinity, pH, BOD, COD, BOD/COD ratio, ammonia, chloride, iron and zinc. A total landfill gas indicator score is provided using multi-criteria analysis to calculate the sum of weighted scores for each indicator. The weights for each indicator are calculated using an analytical hierarchical process. The tool is tested against five real scenarios for landfill sites in UK with a range of good, average and poor landfill methane generation over a one year period (2012). An interpretation of the results is given for each scenario and recommendations are highlighted for methane output rate enhancement. Results demonstrate how the tool can help landfill managers and operators to enhance their understanding of methane generation at a site-specific level, track landfill methane generation over time, compare and rank sites, and identify problems areas within a landfill site. PMID:26168873

  12. A decision support tool for landfill methane generation and gas collection.

    PubMed

    Emkes, Harriet; Coulon, Frédéric; Wagland, Stuart

    2015-09-01

    This study presents a decision support tool (DST) to enhance methane generation at individual landfill sites. To date there is no such tool available to provide landfill decision makers with clear and simplified information to evaluate biochemical processes within a landfill site, to assess performance of gas production and to identify potential remedies to any issues. The current lack in understanding stems from the complexity of the landfill waste degradation process. Two scoring sets for landfill gas production performance are calculated with the tool: (1) methane output score which measures the deviation of the actual methane output rate at each site which the prediction generated by the first order decay model LandGEM; and (2) landfill gas indicators' score, which measures the deviation of the landfill gas indicators from their ideal ranges for optimal methane generation conditions. Landfill gas indicators include moisture content, temperature, alkalinity, pH, BOD, COD, BOD/COD ratio, ammonia, chloride, iron and zinc. A total landfill gas indicator score is provided using multi-criteria analysis to calculate the sum of weighted scores for each indicator. The weights for each indicator are calculated using an analytical hierarchical process. The tool is tested against five real scenarios for landfill sites in UK with a range of good, average and poor landfill methane generation over a one year period (2012). An interpretation of the results is given for each scenario and recommendations are highlighted for methane output rate enhancement. Results demonstrate how the tool can help landfill managers and operators to enhance their understanding of methane generation at a site-specific level, track landfill methane generation over time, compare and rank sites, and identify problems areas within a landfill site.

  13. Comparison of green-house gas emission reductions and landfill gas utilization between a landfill system and an incineration system.

    PubMed

    Haibin Han; Jisheng Long; Shude Li; Guangren Qian

    2010-04-01

    Electricity generation and greenhouse gas (GHG) reductions were researched by making comparisons between municipal solid waste (MSW) landfill and incineration systems with three different electricity generation efficiencies - 10%, 21%, and 24.7%. For MSW landfill systems, it is shown that the total electricity generation is 198,747 MWh, and the total GHG emission reduction is 1,386,081 tonne CO( 2) during a 21-year operation period. For incineration systems, the total electricity generation is 611,801 MWh, and the total GHG emission reduction is 1,339,158 tonne CO(2) during a 10-year operation period even if the electricity generation efficiency is only 10%. It is also shown that electricity generation increases quicker than the GHG emission reductions with the increase of electricity generation efficiency. However, incineration systems show great superiority in LFG utilisation and GHG emission reductions.

  14. Lateral gas transport in soil adjacent to an old landfill: factors governing gas migration.

    PubMed

    Christophersen, M; Kjeldsen, P

    2001-12-01

    Field experiments investigating lateral gas transport in soil adjacent to an old landfill in Denmark during a one-year period were conducted. A significant seasonal variation, with low concentrations of methane and high concentrations of carbon dioxide in the summer, caused by methane oxidation was observed. There was a good correlation between pressure above the barometric pressure and the methane concentration in the soil, indicating that advective flow was the controlling process. This was confirmed by calculations. Diurnal measurement during a drop in barometric pressure showed that lateral migration of landfill gas was a very dynamic system and the concentrations of LFG at a specific place and depth changed dramatically within a very short time. The experiments showed that change in barometric pressure was an important factor affecting gas migration at the Skellingsted landfill in Denmark.

  15. Feasibility of landfill gas as a liquefied natural gas fuel source for refuse trucks.

    PubMed

    Zietsman, Josias; Bari, Muhammad Ehsanul; Rand, Aaron J; Gokhale, Bhushan; Lord, Dominique; Kumar, Sunil

    2008-05-01

    The purpose of this paper is to develop a methodology to evaluate the feasibility of using landfill gas (LFG) as a liquefied natural gas (LNG) fuel source for heavy-duty refuse trucks operating on landfills. Using LFG as a vehicle fuel can make the landfills more self-sustaining, reduce their dependence on fossil fuels, and reduce emissions and greenhouse gases. Acrion Technologies Inc. in association with Mack Trucks Inc. developed a technology to generate LNG from LFG using the CO2 WASH process. A successful application of this process was performed at the Eco Complex in Burlington County, PA. During this application two LNG refuse trucks were operated for 600 hr each using LNG produced from gases from the landfill. The methodology developed in this paper can evaluate the feasibility of three LFG options: doing nothing, electricity generation, and producing LNG to fuel refuse trucks. The methodology involved the modeling of several components: LFG generation, energy recovery processes, fleet operations, economic feasibility, and decision-making. The economic feasibility considers factors such as capital, maintenance, operational, and fuel costs, emissions and tax benefits, and the sale of products such as surplus LNG and food-grade carbon dioxide (CO2). Texas was used as a case study. The 96 landfills in Texas were prioritized and 17 landfills were identified that showed potential for converting LFG to LNG for use as a refuse truck fuel. The methodology was applied to a pilot landfill in El Paso, TX. The analysis showed that converting LFG to LNG to fuel refuse trucks proved to be the most feasible option and that the methodology can be applied for any landfill that considers this option.

  16. Feasibility of landfill gas as a liquefied natural gas fuel source for refuse trucks.

    PubMed

    Zietsman, Josias; Bari, Muhammad Ehsanul; Rand, Aaron J; Gokhale, Bhushan; Lord, Dominique; Kumar, Sunil

    2008-05-01

    The purpose of this paper is to develop a methodology to evaluate the feasibility of using landfill gas (LFG) as a liquefied natural gas (LNG) fuel source for heavy-duty refuse trucks operating on landfills. Using LFG as a vehicle fuel can make the landfills more self-sustaining, reduce their dependence on fossil fuels, and reduce emissions and greenhouse gases. Acrion Technologies Inc. in association with Mack Trucks Inc. developed a technology to generate LNG from LFG using the CO2 WASH process. A successful application of this process was performed at the Eco Complex in Burlington County, PA. During this application two LNG refuse trucks were operated for 600 hr each using LNG produced from gases from the landfill. The methodology developed in this paper can evaluate the feasibility of three LFG options: doing nothing, electricity generation, and producing LNG to fuel refuse trucks. The methodology involved the modeling of several components: LFG generation, energy recovery processes, fleet operations, economic feasibility, and decision-making. The economic feasibility considers factors such as capital, maintenance, operational, and fuel costs, emissions and tax benefits, and the sale of products such as surplus LNG and food-grade carbon dioxide (CO2). Texas was used as a case study. The 96 landfills in Texas were prioritized and 17 landfills were identified that showed potential for converting LFG to LNG for use as a refuse truck fuel. The methodology was applied to a pilot landfill in El Paso, TX. The analysis showed that converting LFG to LNG to fuel refuse trucks proved to be the most feasible option and that the methodology can be applied for any landfill that considers this option. PMID:18512437

  17. Development of the utilization of combustible gas produced in existing sanitary landfills: effects of corrosion at the Mountain View, CA Landfill Gas-Recovery Plant

    SciTech Connect

    Not Available

    1982-10-01

    Corrosion of equipment has occurred at the Mountain View, California Landfill Gas Recovery Plant. Corrosion is most severe on compressor valve seats and cages, tubes in the first and second stages of the interstage gas cooler, and first and second stage piping and liquid separators. Corrosion occurs because the raw landfill gas contains water, carbon dioxide, and oxygen. Some corrosion may also result from trace concentrations of organic acids present in the landfill gas. Corrosion of the third stage compressor, cooler, and piping does not occur because the gas is dehydrated immediately prior to the third stage. Controlling corrosion is necessary to maintain the mechanical integrity of the plant and to keep the cost of the gas competitive with natural gas. Attempts to reduce corrosion rates by injecting a chemical inhibitor have proved only partially successful. Recommendations for dealing with corrosion include earlier dehydration of the gas, selection of special alloys in critical locations, chemical inhibition, and regular plant inspections.

  18. LANDFILL GAS EMISSIONS MODEL (LANDGEM) VERSION 3.02 USER'S GUIDE

    EPA Science Inventory

    The Landfill Gas Emissions Model (LandGEM) is an automated estimation tool with a Microsoft Excel interface that can be used to estimate emission rates for total landfill gas, methane, carbon dioxide, nonmethane organic compounds, and individual air pollutants from municipal soli...

  19. Improved methodology to assess modification and completion of landfill gas management in the aftercare period

    SciTech Connect

    Morris, Jeremy W.F.; Crest, Marion; Barlaz, Morton A.; Spokas, Kurt A.; Akerman, Anna; Yuan, Lei

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Performance-based evaluation of landfill gas control system. Black-Right-Pointing-Pointer Analytical framework to evaluate transition from active to passive gas control. Black-Right-Pointing-Pointer Focus on cover oxidation as an alternative means of passive gas control. Black-Right-Pointing-Pointer Integrates research on long-term landfill behavior with practical guidance. - Abstract: Municipal solid waste landfills represent the dominant option for waste disposal in many parts of the world. While some countries have greatly reduced their reliance on landfills, there remain thousands of landfills that require aftercare. The development of cost-effective strategies for landfill aftercare is in society's interest to protect human health and the environment and to prevent the emergence of landfills with exhausted aftercare funding. The Evaluation of Post-Closure Care (EPCC) methodology is a performance-based approach in which landfill performance is assessed in four modules including leachate, gas, groundwater, and final cover. In the methodology, the objective is to evaluate landfill performance to determine when aftercare monitoring and maintenance can be reduced or possibly eliminated. This study presents an improved gas module for the methodology. While the original version of the module focused narrowly on regulatory requirements for control of methane migration, the improved gas module also considers best available control technology for landfill gas in terms of greenhouse gas emissions, air quality, and emissions of odoriferous compounds. The improved module emphasizes the reduction or elimination of fugitive methane by considering the methane oxidation capacity of the cover system. The module also allows for the installation of biologically active covers or other features designed to enhance methane oxidation. A methane emissions model, CALMIM, was used to assist with an assessment of the methane oxidation capacity of

  20. Analysis of a landfill gas to energy system at the municipal solid waste landfill in Gaziantep, Turkey.

    PubMed

    Tercan, Safak Hengirmen; Cabalar, Ali Firat; Yaman, Gokhan

    2015-08-01

    This paper presents an analysis of the electricity generation from municipal solid waste (MSW), via landfill gas valorization technology, at the landfill of Gaziantep City, Turkey. Rapid increase in population, and industrial developments, throughout the world including Turkey results in larger amount of waste materials generated, increased need for energy, and adverse affects on the environment and human health. Turkey plans to produce 1/3 of its electricity demand using renewable energy sources by the year of 2023. It is recommended to use each year around 25 million tonnes of the MSW generated nationwide for a renewable energy supply. In this study, a concise summary of current status of electricity generation from a MSW landfill gas plant (via biogas harnessing) located in Gaziantep City was analyzed as a case study.

  1. Numerical modeling of landfill gas and heat transport in the deformable MSW landfill body. Part 1. Development of the model

    NASA Astrophysics Data System (ADS)

    Kutsyi, D. V.

    2015-06-01

    The article is devoted to studying the parameters of wells that are used as part of vertical gas extraction systems for degassing landfills. To this end, approaches to modeling the main processes occurring in the landfill's porous medium are considered. The considered approaches served as a basis for elaborating a thermophysical gas and heat transport model that takes into account variation in the hydrodynamic properties of wastes resulting from their secondary settlement. The adequacy of the results obtained using the developed model is confirmed by the data of classic works. The effect the secondary settlement of wastes has on the distribution of pressure and temperature in the landfill body is determined. It is shown that compaction of wastes due to their secondary settlement results in a growth of pressure by 40% on the average.

  2. Greenhouse gas emissions from landfill leachate treatment plants: a comparison of young and aged landfill.

    PubMed

    Wang, Xiaojun; Jia, Mingsheng; Chen, Xiaohai; Xu, Ying; Lin, Xiangyu; Kao, Chih Ming; Chen, Shaohua

    2014-07-01

    With limited assessment, leachate treatment of a specified landfill is considered to be a significant source of greenhouse gas (GHG) emissions. In our study, the cumulative GHG emitted from the storage ponds and process configurations that manage fresh or aged landfill leachate were investigated. Our results showed that strong CH4 emissions were observed from the fresh leachate storage pond, with the fluxes values (2219-26,489 mg Cm(-2)h(-1)) extremely higher than those of N2O (0.028-0.41 mg Nm(-2)h(-1)). In contrast, the emission values for both CH4 and N2O were low for the aged leachate tank. N2O emissions became dominant once the leachate entered the treatment plants of both systems, accounting for 8-12% of the removal of N-species gases. Per capita, the N2O emission based on both leachate treatment systems was estimated to be 7.99 g N2O-N capita(-1)yr(-1). An increase of 80% in N2O emissions was observed when the bioreactor pH decreased by approximately 1 pH unit. The vast majority of carbon was removed in the form of CO2, with a small portion as CH4 (<0.3%) during both treatment processes. The cumulative GHG emissions for fresh leachate storage ponds, fresh leachate treatment system and aged leachate treatment system were 19.10, 10.62 and 3.63 Gg CO(2) eq yr(-1), respectively, for a total that could be transformed to 9.09 kg CO(2) eq capita(-1)yr(-1).

  3. Tapping Landfill Gas to Provide Significant Energy Savings and Greenhouse Gas Reductions - Case Study

    SciTech Connect

    2013-04-30

    BroadRock Renewables, LLC built two high efficiency electricity generating facilities that utilize landfill gas in California and Rhode Island. The two projects received a total of $25 million in U.S. Department of Energy funding from the American Recovery and Reinvestment Act (ARRA) of 2009. Private-sector cost share for the projects totaled approximately $186 million.

  4. Modelling the behaviour of mechanical biological treatment outputs in landfills using the GasSim model.

    PubMed

    Donovan, S M; Bateson, T; Gronow, J R; Voulvoulis, N

    2010-03-15

    The pretreatment of the biodegradable components of municipal solid waste (MSW) has been suggested as a method of reducing landfill gas emissions. Mechanical biological treatment (MBT) is the technology being developed to provide this reduction in biodegradability, either as an alternative to source segregated collection or for dealing with residual MSW which still contains high levels of biodegradable waste. The compost like outputs (CLOs) from MBT plants can be applied to land as a soil conditioner; treated to produce a solid recovered fuel (SRF) or landfilled. In this study the impact that landfilling of these CLOs will have on gaseous emissions is investigated. It is important that the gas production behaviour of landfilled waste is well understood, especially in European member states where the mitigation of gaseous emissions is a legal requirement. Results of an experiment carried out to characterise the biodegradable components of pretreated biowastes have been used with the GasSim model to predict the long term emissions behaviour of landfills accepting these wastes, in varying quantities. The landfill directive also enforces the mitigation of potential methane emissions from landfills, and the ability of landfill operators to capture gaseous emissions from low emitting landfills of the future is discussed, as well as new techniques that could be used for the mitigation of methane generation. PMID:20092874

  5. Bacterial community composition and abundance in leachate of semi-aerobic and anaerobic landfills.

    PubMed

    Zhang, Wei; Yue, Bo; Wang, Qi; Huang, Zechun; Huang, Qifei; Zhang, Zengqiang

    2011-01-01

    The abundance and phylogenetic composition of bacterial community in leachate of semi-aerobic and anaerobic landfill were compared through real-time polymerase chain reaction and denaturing gradient gel electrophoresis. In semi-aerobic landfill scenario, the bacterial 16S rRNA copy numbers in leachate had no significant reduction from initial stage to stable period. In the scenario of anaerobic landfill, the largest bacterial 16S rRNA gene copy number was found in leachate at initial stage, but it reduced significantly at stable period. Moreover, methane-oxidizing bacteria population in stable period was lower than that in initial period in both two landfill processes. However, semi-aerobic landfill leachate had more methanotrophic bacteria populations than that in the anaerobic one. Furthermore, according to the sequences and phylogenetic analysis, obvious difference could be detected in bacterial community composition in different scenarios. Proteobacteria and bacteroidetes took up a dominantly higher proportion in semi-aerobic landfill leachate. To summarize up, different landfill methods and its landfill ages had crucial impacts on bacterial abundance and composition in leachate of semi-aerobic and anaerobic landfills.

  6. Control of gas from landfills and/or marsh areas

    SciTech Connect

    Hanson, E.H.

    1997-12-31

    Landfills are the most well known source of methane formed by decomposition of organic material, but the authors have found that marsh gas generated by peat deposits also contain large quantities of methane and often become a formidable hazard. This is particularly true when small amounts of refuse or ground wood fill (hog fuel) has been placed on the marsh area to raise the ground elevation. It is well known that there is a natural propensity for methane generation and explosion from municipal solid waste landfills and marshlands. Despite this fact, in the Vancouver area, large, high value land development projects are taking place adjacent to methane generation areas and directly upon them. This is due to rapid growth and the consequent high demand for serviced building lots. Consequently, it became necessary to develop soils gas eradication systems which totally eliminate any danger of methane accumulation in buildings, in waste water and land drainage piping, and in underground electrical and telephone conduits. This was accomplished for a high caliber industrial/commercial site in Coquitlam, B.C. known as Pacific Reach Business Park. The site consists of about 180 acres and is underlain by peat and silt. It then became the recipient of municipal solid waste and ground wood waste (hog fuel), all of which produce methane. Finally it was topped with clay and dredged sand from the Fraser River. The biodegradation of carbon from the refuse plus the cellulose from the wood waste generated high volumes of methane. All of the underground municipal, telephone, and electrical conduits are protected from methane intrusion by a city-owned methane eradication system funded by the developer. The buildings each have built-in, custom designed, protection systems. Development is about 75% completed.

  7. Greenhouse gas emissions from landfill leachate treatment plants: A comparison of young and aged landfill

    SciTech Connect

    Wang, Xiaojun; Jia, Mingsheng; Chen, Xiaohai; Xu, Ying; Lin, Xiangyu; Kao, Chih Ming; Chen, Shaohua

    2014-07-15

    Highlights: • Young and aged leachate works accounted for 89.1% and 10.9% of 33.35 Gg CO{sub 2} yr{sup −1}. • Fresh leachate owned extremely low ORP and high organic matter content. • Strong CH{sub 4} emissions occurred in the fresh leachate ponds, but small in the aged. • N{sub 2}O emissions became dominant in the treatment units of both systems. • 8.45–11.9% of nitrogen was removed as the form of N{sub 2}O under steady-state. - Abstract: With limited assessment, leachate treatment of a specified landfill is considered to be a significant source of greenhouse gas (GHG) emissions. In our study, the cumulative GHG emitted from the storage ponds and process configurations that manage fresh or aged landfill leachate were investigated. Our results showed that strong CH{sub 4} emissions were observed from the fresh leachate storage pond, with the fluxes values (2219–26,489 mg C m{sup −2} h{sup −1}) extremely higher than those of N{sub 2}O (0.028–0.41 mg N m{sup −2} h{sup −1}). In contrast, the emission values for both CH{sub 4} and N{sub 2}O were low for the aged leachate tank. N{sub 2}O emissions became dominant once the leachate entered the treatment plants of both systems, accounting for 8–12% of the removal of N-species gases. Per capita, the N{sub 2}O emission based on both leachate treatment systems was estimated to be 7.99 g N{sub 2}O–N capita{sup −1} yr{sup −1}. An increase of 80% in N{sub 2}O emissions was observed when the bioreactor pH decreased by approximately 1 pH unit. The vast majority of carbon was removed in the form of CO{sub 2}, with a small portion as CH{sub 4} (<0.3%) during both treatment processes. The cumulative GHG emissions for fresh leachate storage ponds, fresh leachate treatment system and aged leachate treatment system were 19.10, 10.62 and 3.63 Gg CO{sub 2} eq yr{sup −1}, respectively, for a total that could be transformed to 9.09 kg CO{sub 2} eq capita{sup −1} yr{sup −1}.

  8. Landfill Gas Energy Cost Model Version 3.0 (LFGcost-Web V3.0)

    EPA Science Inventory

    To help stakeholders estimate the costs of a landfill gas (LFG) energy project, in 2002, LMOP developed a cost tool (LFGcost). Since then, LMOP has routinely updated the tool to reflect changes in the LFG energy industry. Initially the model was designed for EPA to assist landfil...

  9. U.S. EPA'S FIELD TEST PROGRAMS TO UPDATE DATA ON LANDFILL GAS EMISSIONS

    EPA Science Inventory

    The paper discusses a field test program in which the EPA is currently engaged to improve data on landfill gas (LFG) emissions. LFG emissions data in use at this time are based on determinations made in the late 1980s and early 1990s; changes in landfill operations, such as using...

  10. Estimates of solid waste disposal rates and reduction targets for landfill gas emissions

    NASA Astrophysics Data System (ADS)

    Powell, Jon T.; Townsend, Timothy G.; Zimmerman, Julie B.

    2016-02-01

    Landfill disposal of municipal solid waste represents one of the largest anthropogenic global methane emission sources, and recent policy approaches have targeted significant reductions of these emissions to combat climate change in the US (ref. ). The efficacy of active gas collection systems in the US was examined by analysing performance data, including fire occurrence, from more than 850 landfills. A generalized linear model showed that the operating status of a landfill--open and actively receiving waste or closed--was the most significant predictor of collection system performance. Gas collection systems at closed landfills were statistically significantly more efficient (p < 0.001) and on average 17 percentage points more efficient than those at open landfills, but open landfills were found to represent 91% of all landfill methane emissions. These results demonstrate the clear need to target open landfills to achieve significant near-term methane emission reductions. This observation is underscored by landfill disposal rates in the US significantly exceeding previously reported national estimates, with this study reporting 262 million tonnes in the year 2012 compared with 122 million tonnes in 2012 as estimated by the US Environmental Protection Agency.

  11. Effects of a temporary HDPE cover on landfill gas emissions: multiyear evaluation with the static chamber approach at an Italian landfill.

    PubMed

    Capaccioni, Bruno; Caramiello, Cristina; Tatàno, Fabio; Viscione, Alessandro

    2011-05-01

    According to the European Landfill Directive 1999/31/EC and the related Italian Legislation ("D. Lgs. No. 36/2003"), monitoring and control procedures of landfill gas emissions, migration and external dispersions are clearly requested. These procedures could be particularly interesting in the operational circumstance of implementing a temporary cover, as for instance permitted by the Italian legislation over worked-out landfill sections, awaiting the evaluation of expected waste settlements. A possible quantitative approach for field measurement and consequential evaluation of landfill CO(2), CH(4) emission rates in pairs consists of the static, non-stationary accumulation chamber technique. At the Italian level, a significant and recent situation of periodical landfill gas emission monitoring is represented by the sanitary landfill for non-hazardous waste of the "Fano" town district, where monitoring campaigns with the static chamber have been annually conducted during the last 5 years (2005-2009). For the entire multiyear monitoring period, the resulting CO(2), CH(4) emission rates varied on the whole up to about 13,100g CO(2) m(-2)d(-1) and 3800 g CH(4) m(-2)d(-1), respectively. The elaboration of these landfill gas emission data collected at the "Fano" case-study site during the monitoring campaigns, presented and discussed in the paper, gives rise to a certain scientific evidence of the possible negative effects derivable from the implementation of a temporary HDPE cover over a worked-out landfill section, notably: the lateral migration and concentration of landfill gas emissions through adjacent, active landfill sections when hydraulically connected; and consequently, the increase of landfill gas flux velocities throughout the reduced overall soil cover surface, giving rise to a flowing through of CH(4) emissions without a significant oxidation. Thus, these circumstances are expected to cause a certain increase of the overall GHG emissions from the given

  12. Investigation of Integrated Subsurface Processing of Landfill Gas and Carbon Sequestration, Johnson County, Kansas

    SciTech Connect

    K. David Newell; Timothy R. Carr

    2007-03-31

    The Johnson County Landfill in Shawnee, KS is operated by Deffenbaugh Industries and serves much of metropolitan Kansas City. Refuse, which is dumped in large plastic-underlined trash cells covering several acres, is covered over with shale shortly after burial. The landfill waste, once it fills the cell, is then drilled by Kansas City LFG, so that the gas generated by anaerobic decomposition of the refuse can be harvested. Production of raw landfill gas from the Johnson County landfill comes from 150 wells. Daily production is approximately 2.2 to 2.5 mmcf, of which approximately 50% is methane and 50% is carbon dioxide and NMVOCs (non-methane volatile organic compounds). Heating value is approximately 550 BTU/scf. A upgrading plant, utilizing an amine process, rejects the carbon dioxide and NMVOCs, and upgrades the gas to pipeline quality (i.e., nominally a heating value >950 BTU/scf). The gas is sold to a pipeline adjacent to the landfill. With coal-bearing strata underlying the landfill, and carbon dioxide a major effluent gas derived from the upgrading process, the Johnson County Landfill is potentially an ideal setting to study the feasibility of injecting the effluent gas in the coals for both enhanced coalbed methane recovery and carbon sequestration. To these ends, coals below the landfill were cored and then were analyzed for their thickness and sorbed gas content, which ranged up to 79 scf/ton. Assuming 1 1/2 square miles of land (960 acres) at the Johnson County Landfill can be utilized for coalbed and shale gas recovery, the total amount of in-place gas calculates to 946,200 mcf, or 946.2 mmcf, or 0.95 bcf (i.e., 985.6 mcf/acre X 960 acres). Assuming that carbon dioxide can be imbibed by the coals and shales on a 2:1 ratio compared to the gas that was originally present, then 1682 to 1720 days (4.6 to 4.7 years) of landfill carbon dioxide production can be sequestered by the coals and shales immediately under the landfill. Three coal--the Bevier

  13. GUIDANCE FOR EVALUATING LANDFILL GAS EMISSIONS FROM CLOSED OR ABANDONED FACILITIES

    EPA Science Inventory

    This document provides guidance to Superfund remedial project managers, on scene coordinators, facility owners, and potentially responsible parties for conducting an air pathway analysis for landfill gas (LFG) emissions under the Comprehensive Environmental Response, Compensation...

  14. Photoacoustic infrared spectroscopy for conducting gas tracer tests and measuring water saturations in landfills

    SciTech Connect

    Jung, Yoojin; Han, Byunghyun; Mostafid, M. Erfan; Chiu, Pei; Yazdani, Ramin; Imhoff, Paul T.

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Photoacoustic infrared spectroscopy tested for measuring tracer gas in landfills. Black-Right-Pointing-Pointer Measurement errors for tracer gases were 1-3% in landfill gas. Black-Right-Pointing-Pointer Background signals from landfill gas result in elevated limits of detection. Black-Right-Pointing-Pointer Technique is much less expensive and easier to use than GC. - Abstract: Gas tracer tests can be used to determine gas flow patterns within landfills, quantify volatile contaminant residence time, and measure water within refuse. While gas chromatography (GC) has been traditionally used to analyze gas tracers in refuse, photoacoustic spectroscopy (PAS) might allow real-time measurements with reduced personnel costs and greater mobility and ease of use. Laboratory and field experiments were conducted to evaluate the efficacy of PAS for conducting gas tracer tests in landfills. Two tracer gases, difluoromethane (DFM) and sulfur hexafluoride (SF{sub 6}), were measured with a commercial PAS instrument. Relative measurement errors were invariant with tracer concentration but influenced by background gas: errors were 1-3% in landfill gas but 4-5% in air. Two partitioning gas tracer tests were conducted in an aerobic landfill, and limits of detection (LODs) were 3-4 times larger for DFM with PAS versus GC due to temporal changes in background signals. While higher LODs can be compensated by injecting larger tracer mass, changes in background signals increased the uncertainty in measured water saturations by up to 25% over comparable GC methods. PAS has distinct advantages over GC with respect to personnel costs and ease of use, although for field applications GC analyses of select samples are recommended to quantify instrument interferences.

  15. Observations from using models to fit the gas production of varying volume test cells and landfills.

    PubMed

    Lamborn, Julia

    2012-12-01

    Landfill operators are looking for more accurate models to predict waste degradation and landfill gas production. The simple microbial growth and decay models, whilst being easy to use, have been shown to be inaccurate. Many of the newer and more complex (component) models are highly parameter hungry and many of the required parameters have not been collected or measured at full-scale landfills. This paper compares the results of using different models (LANDGEM, HBM, and two Monod models developed by the author) to fit the gas production of laboratory scale, field test cell and full-scale landfills and discusses some observations that can be made regarding the scalability of gas generation rates. The comparison of these results show that the fast degradation rate that occurs at laboratory scale is not replicated at field-test cell and full-scale landfills. At small scale, all the models predict a slower rate of gas generation than actually occurs. At field test cell and full-scale a number of models predict a faster gas generation than actually occurs. Areas for future work have been identified, which include investigations into the capture efficiency of gas extraction systems and into the parameter sensitivity and identification of the critical parameters for field-test cell and full-scale landfill predication.

  16. The Measurement of Landfill Gas Emissions with the Orbiting Carbon Observatory and CarbonSAT Satellites

    NASA Astrophysics Data System (ADS)

    Vigil, S. A.; Bovensmann, H.

    2010-12-01

    Landfill gas is a significant contributor to anthropogenic emissions of CH4 and CO2. The U.S. Environmental Protection Agency has estimated the total U.S. 2007 emissions of the CH4 component of landfill gas at 132.9 Tg CO2 Equivalent. This compares to total CH4 emission from all US sources in 2007 at 585.3 Tg CO2 Equivalent. Worldwide CH4 emissions from landfill gas have been estimated at 668 Tg CO2 Equivalent. Satellite remote sensing can also be used to characterize landfill gas emissions. The NASA Orbiting Carbon Observatory (OCO-2) and the proposed CarbonSAT (University of Bremen) satellites are particularly suited for this purpose. The Orbiting Carbon Observatory (OCO) was designed to provided high spatial resolution ( < 3 km2 footprints) and high accuracy ( 0.5 to 3 ppm) CO2 measurements. The original OCO satellite failed to achieve orbit in February 2009. A replacement satellite (OCO-2) is under construction and scheduled for launch in February 2013. These characteristics will allow the measurement of CO2 emissions from large landfills on the orbit path. Because surface landfill gas emissions include both CH4 and CO2 , the CH4 concentration can be inferred from CO2 concentrations. The CarbonSAT satellite which is being designed by the University of Bremen, Institute for Environmental Physics, has similar characteristics to OCO-2 but it has been optimized for measurement of both CH4 and CO2 . Key specifications for the CarbonSAT satellite include XCO2 single measurement error of < 1 to 3 ppm and XCH4 single measurement error of < 10 to 18 ppb. These characteristics will make it possible to detect both CO2 and CH4 emissions from large landfills. The spatial resolution and accuracy of the CO2 measurements from OCO-2 and CO2 and CH4 measurements from CarbonSAT present a unique opportunity to measure landfill gas emissions from large landfills such as exist in the United States and other developed countries. In general, landfills in the developed countries have

  17. Emission assessment at the Burj Hammoud inactive municipal landfill: Viability of landfill gas recovery under the clean development mechanism

    SciTech Connect

    El-Fadel, Mutasem; Abi-Esber, Layale; Salhab, Samer

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer LFG emissions are measured at an abandoned landfill with highly organic waste. Black-Right-Pointing-Pointer Mean headspace and vent emissions are 0.240 and 0.074 l CH{sub 4}/m{sup 2} hr, respectively. Black-Right-Pointing-Pointer At sites with high food waste content, LFG generation drops rapidly after site closure. Black-Right-Pointing-Pointer The viability of LFG recovery for CDMs in developing countries is doubtful. - Abstract: This paper examines landfill gas (LFG) emissions at a large inactive waste disposal site to evaluate the viability of investment in LFG recovery through the clean development mechanism (CDM) initiative. For this purpose, field measurements of LFG emissions were conducted and the data were processed by geospatial interpolation to estimate an equivalent site emission rate which was used to calibrate and apply two LFG prediction models to forecast LFG emissions at the site. The mean CH{sub 4} flux values calculated through tessellation, inverse distance weighing and kriging were 0.188 {+-} 0.014, 0.224 {+-} 0.012 and 0.237 {+-} 0.008 l CH{sub 4}/m{sup 2} hr, respectively, compared to an arithmetic mean of 0.24 l/m{sup 2} hr. The flux values are within the reported range for closed landfills (0.06-0.89 l/m{sup 2} hr), and lower than the reported range for active landfills (0.42-2.46 l/m{sup 2} hr). Simulation results matched field measurements for low methane generation potential (L{sub 0}) values in the range of 19.8-102.6 m{sup 3}/ton of waste. LFG generation dropped rapidly to half its peak level only 4 yrs after landfill closure limiting the sustainability of LFG recovery systems in similar contexts and raising into doubt promoted CDM initiatives for similar waste.

  18. Landfill-gas-to-Energy projects: analysis of net private and social benefits.

    PubMed

    Jaramillo, Paulina; Matthews, H Scott

    2005-10-01

    Methane emissions from municipal landfills represent 3% of the total United States greenhouse gas emissions that contribute to climate change. These methane emissions can be released to the air or collected and flared. This landfill gas also has the potential to be used to generate electricity. In 1994,the Environmental Protection Agency(EPA) created the Landfill Methane Outreach Program, with the objective of promoting the development of landfill-gas-to-energy projects around the country. There are currently 2,300 active landfills in the United States. Although there are already 382 operational projects, there are many more landfills with the potential to use the gas. EPA has identified at least 630 candidate landfills for energy projects, and many more have still not been identified. The objective of this paper is to evaluate total private and social benefits of landfill-gas-to-energy projects, taking into consideration not only the costs of installing and maintaining the necessary equipment and the revenues obtained from selling the electricity but also a valuation of the greenhouse gas emissions that would be prevented and the emissions of criteria pollutants created by the electricity generating equipment. It also evaluates the breakeven government subsidies that would be required to make such projects economically viable from private and social perspectives in comparison to current subsidies. It was found that the private breakeven price of electricity for these projects is lower than dollar 0.04/kWh. Moreover, the optimum social subsidywas found to be less than dollar 0.0085/ kWh, which is about 40% lower than the currently available federal tax break of dollar 0.015/kWh. The method developed for this paper can be applied to other renewable energy technologies, to show their relative social costs and benefits.

  19. Landfill gas effects on groundwater samples at a municipal solid waste facility.

    PubMed

    Kerfoot, H B

    1994-11-01

    A study was performed to determine the source of low concentrations of volatile organic compounds (VOCs) detected in groundwater samples at a solid waste management facility. The affected wells were identified as hydraulically upgradient of an old unlined facility, but downgradient of a new clay-lined landfill. These monitoring wells are close to both sites. Subsurface landfill gas migration was identified after a low permeability cap was installed on the older site. Subsurface gas pressure was monitored to identify horizontal landfill gas migration. Monitoring well headspace gases were evaluated to identify depressed oxygen concentrations and methane because of landfill gas migration into the well. Monitoring well headspace gas VOC concentrations were compared to groundwater VOC concentrations to determine the direction of phase transfer. A ratio above 1.0 of the observed well headspace gas concentration of a VOC to the concentration that would be in equilibrium with the groundwater concentration indicates gas-to-water phase transfer within the well. For the major gas-phase and aqueous-phase VOC, cis-1,2-dichloroethene, gas-to-water phase transfer is clearly indicated from the data for two of the four wells. Fifteen other VOCs were detected in monitoring well headspace gases but not in groundwater samples from the four wells studied. Only one compound in one well was detected in the groundwater sample but not in the headspace gases, and only one compound in one well was detected in both matrices at concentrations that suggested water-to-gas phase transfer. This study suggests that if landfill gas is suspected as the source of detected VOCs, monitoring well construction and stratigraphy are important considerations when attempting to differentiate between groundwater contamination by landfill gas and contamination from other sources.

  20. BUNCOMBE COUNTY WASTEWATER PRE-TREATMENT AND LANDFILL GAS TO ENERGY PROJECT

    SciTech Connect

    Jon Creighton

    2012-03-13

    The objective of this project was to construct a landfill gas-to-energy (LFGTE) facility that generates a renewable energy source utilizing landfill gas to power a 1.4MW generator, while at the same time reducing the amount of leachate hauled offsite for treatment. The project included an enhanced gas collection and control system, gas conditioning equipment, and a 1.4 MW generator set. The production of cleaner renewable energy will help offset the carbon footprint of other energy sources that are currently utilized.

  1. Modeling the final phase of landfill gas generation from long-term observations.

    PubMed

    Tintner, Johannes; Kühleitner, Manfred; Binner, Erwin; Brunner, Norbert; Smidt, Ena

    2012-06-01

    For waste management, methane emissions from landfills and their effect on climate change are of serious concern. Current models for biogas generation that focus on the economic use of the landfill gas are usually based on first order chemical reactions (exponential decay), underestimating the long-term emissions of landfills. The presented study concentrated on the curve fitting and the quantification of the gas generation during the final degradation phase under optimal anaerobic conditions. For this purpose the long-term gas generation (240-1,830 days) of different mechanically biologically treated (MBT) waste materials was measured. In this study the late gas generation was modeled by a log-normal distribution curve to gather the maximum gas generation potential. According to the log-normal model the observed gas sum curve leads to higher values than commonly used exponential decay models. The prediction of the final phase of landfill gas generation by a fitting model provides a basis for CO(2) balances in waste management and some information to which extent landfills serve as carbon sink.

  2. Gas breakthrough and emission through unsaturated compacted clay in landfill final cover

    SciTech Connect

    Ng, C.W.W.; Chen, Z.K.; Coo, J.L.; Chen, R.; Zhou, C.

    2015-10-15

    Highlights: • Explore feasibility of unsaturated clay as a gas barrier in landfill cover. • Gas breakthrough pressure increases with clay thickness and degree of saturation. • Gas emission rate decreases with clay thickness and degree of saturation. • A 0.6 m-thick clay layer may be sufficient to meet gas emission rate limit. - Abstract: Determination of gas transport parameters in compacted clay plays a vital role for evaluating the effectiveness of soil barriers. The gas breakthrough pressure has been widely studied for saturated swelling clay buffer commonly used in high-level radioactive waste disposal facility where the generated gas pressure is very high (in the order of MPa). However, compacted clay in landfill cover is usually unsaturated and the generated landfill gas pressure is normally low (typically less than 10 kPa). Furthermore, effects of clay thickness and degree of saturation on gas breakthrough and emission rate in the context of unsaturated landfill cover has not been quantitatively investigated in previous studies. The feasibility of using unsaturated compacted clay as gas barrier in landfill covers is thus worthwhile to be explored over a wide range of landfill gas pressures under various degrees of saturation and clay thicknesses. In this study, to evaluate the effectiveness of unsaturated compacted clay to minimize gas emission, one-dimensional soil column tests were carried out on unsaturated compacted clay to determine gas breakthrough pressures at ultimate limit state (high pressure range) and gas emission rates at serviceability limit state (low pressure range). Various degrees of saturation and thicknesses of unsaturated clay sample were considered. Moreover, numerical simulations were carried out using a coupled gas–water flow finite element program (CODE-BRIGHT) to better understand the experimental results by extending the clay thickness and varying the degree of saturation to a broader range that is typical at different

  3. A CASE STUDY DEMONSTRATING U.S. EPA GUIDANCE FOR EVALUATING LANDFILL GAS EMISSIONS FROM CLOSED OR ABANDONED FACILITIES--BUSH VALLEY LANDFILL, HARFORD COUNTY, MARYLAND

    EPA Science Inventory

    The purpose of the activities described in this document is to provide a demonstration of the procedures and methodologies described within the "Guidance for Evaluating Landfill Gas Emissions from Closed or Abandoned Facilities" (Guidance). This demonstration provides an example ...

  4. Sensitivity analysis of the waste composition and water content parameters on the biogas production models on solid waste landfills

    NASA Astrophysics Data System (ADS)

    Rodrigo-Ilarri, Javier; Segura-Sobrino, Francisco; Rodrigo-Clavero, Maria-Elena

    2014-05-01

    Landfills are commonly used as the final deposit of urban solid waste. Despite the waste is previously processed on a treatment plant, the final amount of organic matter which reaches the landfill is large however. The biodegradation of this organic matter forms a mixture of greenhouse gases (essentially Methane and Carbon-Dioxide as well as Ammonia and Hydrogen Sulfide). From the environmental point of view, solid waste landfills are therefore considered to be one of the main greenhouse gas sources. Different mathematical models are usually applied to predict the amount of biogas produced on real landfills. The waste chemical composition and the availability of water in the solid waste appear to be the main parameters of these models. Results obtained when performing a sensitivity analysis over the biogas production model parameters under real conditions are shown. The importance of a proper characterizacion of the waste as well as the necessity of improving the understanding of the behaviour and development of the water on the unsaturated mass of waste are emphasized.

  5. Recovery Act: Brea California Combined Cycle Electric Generating Plant Fueled by Waste Landfill Gas

    SciTech Connect

    Galowitz, Stephen

    2012-12-31

    The primary objective of the Project was to maximize the productive use of the substantial quantities of waste landfill gas generated and collected at the Olinda Landfill near Brea, California. An extensive analysis was conducted and it was determined that utilization of the waste gas for power generation in a combustion turbine combined cycle facility was the highest and best use. The resulting Project reflected a cost effective balance of the following specific sub-objectives: • Meeting the environmental and regulatory requirements, particularly the compliance obligations imposed on the landfill to collect, process and destroy landfill gas • Utilizing proven and reliable technology and equipment • Maximizing electrical efficiency • Maximizing electric generating capacity, consistent with the anticipated quantities of landfill gas generated and collected at the Olinda Landfill • Maximizing equipment uptime • Minimizing water consumption • Minimizing post-combustion emissions • The Project produced and will produce a myriad of beneficial impacts. o The Project created 360 FTE construction and manufacturing jobs and 15 FTE permanent jobs associated with the operation and maintenance of the plant and equipment. o By combining state-of-the-art gas clean up systems with post combustion emissions control systems, the Project established new national standards for best available control technology (BACT). o The Project will annually produce 280,320 MWh’s of clean energy o By destroying the methane in the landfill gas, the Project will generate CO2 equivalent reductions of 164,938 tons annually. The completed facility produces 27.4 MWnet and operates 24 hours a day, seven days a week.

  6. [Difference of contaminant composition between landfill leachates and groundwater and its reasons].

    PubMed

    He, Xiao-Song; Yu, Hong; Xi, Bei-Dou; Cui, Dong-Yu; Pan, Hong-Wei; Li, Dan

    2014-04-01

    In order to investigate the groundwater pollution by landfill leachates, the distribution characteristics of inorganic salt, organic compounds and heavy metals in leachastes from a simple landfill and groundwater and its reason were study using conventional analysis, fluorescence excitation-emission matrix spectra and multivariate statistical analysis. The results showed that the landfill was heterogeneous, and the extracts from the landfill wastes showed a high concentration of NH4(+) -N, but low contents of Cl-, SO4(2-), dissolved organic matter (DOM) and heavy metals. The nitrification process was blocked due to a strong reducing atmosphere in landfill, which caused a low concentration of NO3(-) -N and NO2(-) -N in leachates. Cu was mainly associated with DOM in leachates, while the distribution of the metals Ba, Cd, Cr, Fe, Mn, Ni, Zn and As was primarily related to hydrophobic organic compounds. The contaminate compositions in different groundwater were similar except for the groundwater under the landfill site. In contrast to landfill leachates, the groundwater showed a low concentration of NH4(+) -N, but high concentrations of Cl-, SO4(2-), DOM, NO3(-) -N and NO2(-) -N except for the groundwater under the landfill site. The organic compounds in the groundwater were mainly originated from microbial activity, and the distribution of the metals Ba, Cd, Cu, Fe, Mn and Ni was mainly related to fluorescecent organic matter in DOM. The results showed that the leak point of landfill leachates can be identified through the cluster analysis method on the basis of the contaminant composition in groundwater. PMID:24946594

  7. Recovery Act: Johnston Rhode Island Combined Cycle Electric Generating Plant Fueled by Waste Landfill Gas

    SciTech Connect

    Galowitz, Stephen

    2013-06-30

    The primary objective of the Project was to maximize the productive use of the substantial quantities of waste landfill gas generated and collected at the Central Landfill in Johnston, Rhode Island. An extensive analysis was conducted and it was determined that utilization of the waste gas for power generation in a combustion turbine combined cycle facility was the highest and best use. The resulting project reflected a cost effective balance of the following specific sub-objectives. 1) Meet environmental and regulatory requirements, particularly the compliance obligations imposed on the landfill to collect, process and destroy landfill gas. 2) Utilize proven and reliable technology and equipment. 3) Maximize electrical efficiency. 4) Maximize electric generating capacity, consistent with the anticipated quantities of landfill gas generated and collected at the Central Landfill. 5) Maximize equipment uptime. 6) Minimize water consumption. 7) Minimize post-combustion emissions. To achieve the Project Objective the project consisted of several components. 1) The landfill gas collection system was modified and upgraded. 2) A State-of-the Art gas clean up and compression facility was constructed. 3) A high pressure pipeline was constructed to convey cleaned landfill gas from the clean-up and compression facility to the power plant. 4) A combined cycle electric generating facility was constructed consisting of combustion turbine generator sets, heat recovery steam generators and a steam turbine. 5) The voltage of the electricity produced was increased at a newly constructed transformer/substation and the electricity was delivered to the local transmission system. The Project produced a myriad of beneficial impacts. 1) The Project created 453 FTE construction and manufacturing jobs and 25 FTE permanent jobs associated with the operation and maintenance of the plant and equipment. 2) By combining state-of-the-art gas clean up systems with post combustion emissions control

  8. Landfill Gas Conversion to LNG and LCO{sub 2}. Final Report

    SciTech Connect

    Brown, W.R.; Cook, W. J.; Siwajek, L.A.

    2000-10-20

    This report summarizes work on the development of a process to produce LNG (liquefied methane) for heavy vehicle use from landfill gas (LFG) using Acrion's CO{sub 2} wash process for contaminant removal and CO{sub 2} recovery. Work was done in the following areas: (1) production of natural gas pipeline methane for liquefaction at an existing LNG facility, (2) production of LNG from sewage digester gas, (3) the use of mixed refrigerants for process cooling in the production of LNG, liquid CO{sub 2} and pipeline methane, (4) cost estimates for an LNG production facility at the Arden Landfill in Washington PA.

  9. Methylated mercury species in municipal waste landfill gas sampled in Florida, USA

    NASA Astrophysics Data System (ADS)

    Lindberg, S. E.; Wallschläger, D.; Prestbo, E. M.; Bloom, N. S.; Price, J.; Reinhart, D.

    Mercury-bearing material has been placed in municipal landfills from a wide array of sources including fluorescent lights, batteries, electrical switches, thermometers, and general waste. Despite its known volatility, persistence, and toxicity in the environment, the fate of mercury in landfills has not been widely studied. The nature of landfills designed to reduce waste through generation of methane by anaerobic bacteria suggests the possibility that these systems might also serve as bioreactors for the production of methylated mercury compounds. The toxicity of such species mandates the need to determine if they are emitted in municipal landfill gas (LFG). In a previous study, we had measured levels of total gaseous mercury (TGM) in LFG in the μg/m 3 range in two Florida landfills, and elevated levels of monomethyl mercury (MMM) were identified in LFG condensate, suggesting the possible existence of gaseous organic Hg compounds in LFG. In the current study, we measured TGM, Hg 0, and methylated mercury compounds directly in LFG from another Florida landfill. Again, TGM was in the μg/m 3 range, MMM was found in condensate, and this time we positively identified dimethyl mercury (DMM) in the LGF in the ng/m 3 range. These results identify landfills as a possible anthropogenic source of DMM emissions to air, and may help explain the reports of MMM in continental rainfall.

  10. The Use of Biofilter to Reduce Atmospheric Global Warming Gas (CH4) Eemissions from Landfills

    NASA Astrophysics Data System (ADS)

    Park, S.; Thomas, J. C.; Brown, K. W.; Sung, K.

    2001-12-01

    The emission of greenhouse gasses resulting from anthropogenic activities is increasing the atmospheric concentration of these gases, which can influence the climatic system by changing the temperature, precipitation, wind and other climate factors. Methane (CH4) is a very potent greenhouse gas and CH4 emission from landfills in US has been reported as 37% of total anthropogenic source of CH4 emission. Properly designed soil biofilters may reduce atmospheric CH4 emissions from landfills and help reduce the accumulation of greenhouse gasses in the atmosphere. Biofilter performance was tested under a variety of environmental and design conditions. The results showed that biofilters have the potential to reduce CH4 emissions from landfills by as much as 83%. A quadratic equation was developed to describe the dependence of methane oxidation rate in a sandy loam textured soil as a function of soil temperature, soil moisture and ammonium nitrogen concentration. Using this equation and the averaged soil temperature and moisture contents, and census data for the largest cities of each of the 48 contiguous states, oxidation rates was calculated. A methane emission model was also developed to estimate the methane emission from municipal waste landfills with different covers. Older landfills with soil covers emitted an average of 83% of the generated CH4. Landfills with RCRA covers emitted 90% of the generated CH4 without biofilters and only 10% with biofilters. Thus, the installation of properly sized biofilters should significantly reduce atmospheric CH4 emissions from landfills.

  11. DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM LANDFILL GAS: PHASE II. PRETREATMENT SYSTEM PERFORMANCE MEASUREMENT

    EPA Science Inventory

    The report describes Phase II of a demonstration of the utilization of commercial phosphoric acid fuel cells to recover energy from landfill gas. This phase consisted primarily of the construction and testing of a Gas Pretreatment Unit (GPU) whose function is to remove those impu...

  12. Suitability of Tedlar gas sampling bags for siloxane quantification in landfill gas.

    PubMed

    Ajhar, M; Wens, B; Stollenwerk, K H; Spalding, G; Yüce, S; Melin, T

    2010-06-30

    Landfill or digester gas can contain man-made volatile methylsiloxanes (VMS), usually in the range of a few milligrams per normal cubic metre (Nm(3)). Until now, no standard method for siloxane quantification exists and there is controversy with respect to which sampling procedure is most suitable. This paper presents an analytical and a sampling procedure for the quantification of common VMS in biogas via GC-MS and polyvinyl fluoride (Tedlar) bags. Two commercially available Tedlar bag models are studied. One is equipped with a polypropylene valve with integrated septum, the other with a dual port fitting made from stainless steel. Siloxane recovery in landfill gas samples is investigated as a function of storage time, temperature, surface-to-volume ratio and background gas. Recovery was found to depend on the type of fitting employed. The siloxanes sampled in the bag with the polypropylene valve show high and stable recovery, even after more than 30 days. Sufficiently low detection limits below 10 microg Nm(-3) and good reproducibility can be achieved. The method is therefore well applicable to biogas, greatly facilitating sampling in comparison with other common techniques involving siloxane enrichment using sorption media.

  13. Treating landfill gas hydrogen sulphide with mineral wool waste (MWW) and rod mill waste (RMW).

    PubMed

    Bergersen, Ove; Haarstad, Ketil

    2014-01-01

    Hydrogen sulphide (H2S) gas is a major odorant at municipal landfills. The gas can be generated from different waste fractions, for example demolition waste containing gypsum based plaster board. The removal of H2S from landfill gas was investigated by filtering it through mineral wool waste products. The flow of gas varied from 0.3 l/min to 3.0 l/min. The gas was typical for landfill gas with a mean H2S concentration of ca. 4500 ppm. The results show that the sulphide gas can effectively be removed by mineral wool waste products. The ratios of the estimated potential for sulphide precipitation were 19:1 for rod mill waste (RMW) and mineral wool waste (MWW). A filter consisting of a mixture of MWW and RMW, with a vertical perforated gas tube through the center of filter material and with a downward gas flow, removed 98% of the sulfide gas over a period of 80 days. A downward gas flow was more efficient in contacting the filter materials. Mineral wool waste products are effective in removing hydrogen sulphide from landfill gas given an adequate contact time and water content in the filter material. Based on the estimated sulphide removal potential of mineral wool and rod mill waste of 14 g/kg and 261 g/kg, and assuming an average sulphide gas concentration of 4500 ppm, the removal capacity in the filter materials has been estimated to last between 11 and 308 days. At the studied location the experimental gas flow was 100 times less than the actual gas flow. We believe that the system described here can be upscaled in order to treat this gas flow.

  14. Terrestrial laser scanning for detection of landfill gas: a pilot study

    NASA Astrophysics Data System (ADS)

    Reshetyuk, Yuriy; Mårtensson, Stig-Göran

    2014-04-01

    Methane built up in landfills as a result of breaking down of organic materials can be a renewable energy source if it is taken advantage of. The aim of research presented in this paper is to detect landfill gas (that contains methane) by means of terrestrial laser scanning. The hypothesis is that where no surface leakage has been reported, the landfill gas will expand or migrate. Therefore, it is possible to detect it through repeated scanning of the same area and comparison of Digital Terrain Models (DTMs) generated from the point clouds. Only the most significant movements, i.e. vertical, are of interest in this case. During September-November 2011, a small area at Forsbacka landfill in the vicinity of Gävle was scanned 10 times. Epoch-to-epoch comparisons of the resulting DTMs have shown two significant changes (-27 and +19 mm) in elevation of the surface, and it is not impossible that they are caused by migrating landfill gas. The method tested in this study is deemed to be rigorous and accurate for detecting small-scale swell-shrink behaviour of the ground surface (in our case a landfill surface). However, both data processing and interpretation of the results have been considerably complicated by presence of low vegetation (weeds) on the study site, which was dificult to filter away completely from the data. Based on our pilot study, we recommend that a larger area and a longer period of time are chosen to give basis for more grounded conclusions about presence of landfill gas.

  15. Gas breakthrough and emission through unsaturated compacted clay in landfill final cover.

    PubMed

    Ng, C W W; Chen, Z K; Coo, J L; Chen, R; Zhou, C

    2015-10-01

    Determination of gas transport parameters in compacted clay plays a vital role for evaluating the effectiveness of soil barriers. The gas breakthrough pressure has been widely studied for saturated swelling clay buffer commonly used in high-level radioactive waste disposal facility where the generated gas pressure is very high (in the order of MPa). However, compacted clay in landfill cover is usually unsaturated and the generated landfill gas pressure is normally low (typically less than 10 kPa). Furthermore, effects of clay thickness and degree of saturation on gas breakthrough and emission rate in the context of unsaturated landfill cover has not been quantitatively investigated in previous studies. The feasibility of using unsaturated compacted clay as gas barrier in landfill covers is thus worthwhile to be explored over a wide range of landfill gas pressures under various degrees of saturation and clay thicknesses. In this study, to evaluate the effectiveness of unsaturated compacted clay to minimize gas emission, one-dimensional soil column tests were carried out on unsaturated compacted clay to determine gas breakthrough pressures at ultimate limit state (high pressure range) and gas emission rates at serviceability limit state (low pressure range). Various degrees of saturation and thicknesses of unsaturated clay sample were considered. Moreover, numerical simulations were carried out using a coupled gas-water flow finite element program (CODE-BRIGHT) to better understand the experimental results by extending the clay thickness and varying the degree of saturation to a broader range that is typical at different climate conditions. The results of experimental study and numerical simulation reveal that as the degree of saturation and thickness of clay increase, the gas breakthrough pressure increases but the gas emission rate decreases significantly. Under a gas pressure of 10 kPa (the upper bound limit of typical landfill gas pressure), a 0.6m or thicker

  16. Gas breakthrough and emission through unsaturated compacted clay in landfill final cover.

    PubMed

    Ng, C W W; Chen, Z K; Coo, J L; Chen, R; Zhou, C

    2015-10-01

    Determination of gas transport parameters in compacted clay plays a vital role for evaluating the effectiveness of soil barriers. The gas breakthrough pressure has been widely studied for saturated swelling clay buffer commonly used in high-level radioactive waste disposal facility where the generated gas pressure is very high (in the order of MPa). However, compacted clay in landfill cover is usually unsaturated and the generated landfill gas pressure is normally low (typically less than 10 kPa). Furthermore, effects of clay thickness and degree of saturation on gas breakthrough and emission rate in the context of unsaturated landfill cover has not been quantitatively investigated in previous studies. The feasibility of using unsaturated compacted clay as gas barrier in landfill covers is thus worthwhile to be explored over a wide range of landfill gas pressures under various degrees of saturation and clay thicknesses. In this study, to evaluate the effectiveness of unsaturated compacted clay to minimize gas emission, one-dimensional soil column tests were carried out on unsaturated compacted clay to determine gas breakthrough pressures at ultimate limit state (high pressure range) and gas emission rates at serviceability limit state (low pressure range). Various degrees of saturation and thicknesses of unsaturated clay sample were considered. Moreover, numerical simulations were carried out using a coupled gas-water flow finite element program (CODE-BRIGHT) to better understand the experimental results by extending the clay thickness and varying the degree of saturation to a broader range that is typical at different climate conditions. The results of experimental study and numerical simulation reveal that as the degree of saturation and thickness of clay increase, the gas breakthrough pressure increases but the gas emission rate decreases significantly. Under a gas pressure of 10 kPa (the upper bound limit of typical landfill gas pressure), a 0.6m or thicker

  17. ELECTRIC POWER GENERATION USING A PHOSPHORIC ACID FUEL CELL ON A MUNICIPAL SOLID WASTE LANDFILL GAS STREAM

    EPA Science Inventory

    The report gives results of tests to verify the performance of a landfill gas pretreatment unit (GPU) and a phorsphoric acid fuel cell system. The complete system removes contaminants from landfill gas and produces electricity for on-site use or connection to an electric grid. Th...

  18. Qualitative nontarget analysis of landfill leachate using gas chromatography time-of-flight mass spectrometry.

    PubMed

    Jernberg, Joonas; Pellinen, Jukka; Rantalainen, Anna-Lea

    2013-01-15

    Nontarget analysis means that a sample is analysed without preselection of the studied analytes. While target analysis attempts to determine whether certain selected compounds are present in the sample, nontarget analysis is performed to explore what unknown compounds can be found. We developed a nontarget method using a landfill leachate sample as a complex test sample. The method was based on the use of a gas chromatograph-time-of-flight mass spectrometer (GC-TOF-MS) for final analysis and a deconvolution computer application for data processing. This nontarget analysis method was tested and validated by applying it to a landfill leachate sample spiked with 11 organic pollutants that were treated as unknowns. Sensitivity was found to be the most critical parameter affecting the success of nontarget analysis. The limit of identification (LOI) was 2500 ng L(-1) for four of the 11 compounds, 500 ng L(-1) for three compounds and 100 ng L(-1) for one compound. Three compounds were not detected in any of the spiked samples. A six-stage identification process was developed based on the spiking experiments. The process was based on the forward fit value of the library hit, the number of deconvoluted ions and the accurate mass scoring of the measured ions. The process was applied to an unspiked leachate water sample. Altogether, 44 compounds were tentatively identified in the sample. Elemental compositions of 36 components were additionally determined for which an unequivocal compound identification could not be given. Nontarget analysis with GC-TOF-MS is a promising method for the qualitative analysis of complex water samples. However, we conclude that the computer application for nontarget analysis needs improvement to decrease the amount of manual work needed in the identification process.

  19. Kentucky State Primer. A Primer on Developing Kentucky's Landfill Gas-to-Energy Potential

    NASA Astrophysics Data System (ADS)

    2000-05-01

    Throughout the country, the number of landfill gas-to-energy (LFGTE) projects is growing. Recovering methane gas at solid waste landfills provides significant environmental and economic benefits by eliminating methane emissions while capturing the emissions energy value. The methane captured from landfills can be transformed into a cost-effective fuel source for generating electricity and heat, firing boilers, or even powering vehicles. Permits, incentive programs, and policies for LFGTE project development vary greatly from state to state. To guide LFGTE project developers through the state permitting process and to help them to take advantage of state incentive programs, the U.S. Environmental Protection Agencys (EPAs) Landfill Methane Outreach Program (LMOP) has worked with state agencies to develop individual primers for states participating in the State Ally Program. By presenting the latest information on federal and state regulations and incentives affecting LFGTE projects in this primer, the LMOP and Kentucky state officials hope to facilitate development of many of the landfills listed in Table A. To develop this primer, the Commonwealth of Kentucky identified all the permits and funding programs that could apply to LFGTE projects developed in Kentucky. It should be noted, however, that the regulations, agencies, and policies described are subject to change. Changes are likely to occur whenever a state legislature meets, or when the federal government imposes new directions on state and local governments. LFGTE project developers should verify and continuously monitor the status of laws and rules that might affect their plans or the operations of their projects.

  20. LANDFILL GAS ENERGY UTILIZATION EXPERIENCE: DISCUSSION OF TECHNICAL AND NON-TECHNICAL ISSUES, SOLUTIONS, AND TRENDS

    EPA Science Inventory

    The report discusses technical and non-technical considerations associated with the development and operation of landfill gas to energy projects. Much of the report is based on interviews and site visits with the major developers and operators of the more than 110 projects in the...

  1. Impact of different plants on the gas profile of a landfill cover

    SciTech Connect

    Reichenauer, Thomas G.; Watzinger, Andrea; Riesing, Johann; Gerzabek, Martin H.

    2011-05-15

    Research highlights: > Plants influence gas profile and methane oxidation in landfill covers. > Plants regulate water content and increase the availability of oxygen for methane oxidation. > Plant species with deep roots like alfalfa showed more stimulation of methane oxidation than plants with shallow root systems like grasses. - Abstract: Methane is an important greenhouse gas emitted from landfill sites and old waste dumps. Biological methane oxidation in landfill covers can help to reduce methane emissions. To determine the influence of different plant covers on this oxidation in a compost layer, we conducted a lysimeter study. We compared the effect of four different plant covers (grass, alfalfa + grass, miscanthus and black poplar) and of bare soil on the concentration of methane, carbon dioxide and oxygen in lysimeters filled with compost. Plants were essential for a sustainable reduction in methane concentrations, whereas in bare soil, methane oxidation declined already after 6 weeks. Enhanced microbial activity - expected in lysimeters with plants that were exposed to landfill gas - was supported by the increased temperature of the gas in the substrate and the higher methane oxidation potential. At the end of the first experimental year and from mid-April of the second experimental year, the methane concentration was most strongly reduced in the lysimeters containing alfalfa + grass, followed by poplar, miscanthus and grass. The observed differences probably reflect the different root morphology of the investigated plants, which influences oxygen transport to deeper compost layers and regulates the water content.

  2. Analysis of Indirect Emissions Benefits of Wind, Landfill Gas, and Municipal Solid Waste Generation

    EPA Science Inventory

    Techniques are introduced to calculate the hourly indirect emissions benefits of three types of green power resources: wind energy, municipal solid waste (MSW) combustion, and landfill gas (LFG) combustion. These techniques are applied to each of the U.S. EPA's eGRID subregions i...

  3. DATABASE OF LANDFILL GAS TO ENERGY PROJECTS IN THE UNITED STATES

    EPA Science Inventory

    The paper discusses factors influencing the increase of landfill gas to energy (LFG-E) projects in the U.S. and presents recent statistics from a database,. There has been a dramatic increase in the number of LFG-E projects in the U.S., due to such factors as implementation of t...

  4. DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM LANDFILL GAS - PHASE I FINAL REPORT: CONCEPTUAL STUDY

    EPA Science Inventory

    The report discusses results of a conceptual design, cost, and evaluation study of energy recovery from landfill gas using a commercial phosphoric acid fuel cell power plant. The conceptual design of the fuel cell energy recovery system is described, and its economic and environm...

  5. Effect of persistent trace compounds in landfill gas on engine performance during energy recovery: a case study.

    PubMed

    Sevimoğlu, Orhan; Tansel, Berrin

    2013-01-01

    Performances of gas engines operated with landfill gas (LFG) are affected by the impurities in the LFG, reducing the economic viability of energy recovery. The purpose of this study was to characterize the trace compounds in the LFG at the Odayeri Landfill, Istanbul, Turkey which is used for energy recovery. Composite gas samples were collected and analyzed for trace compounds (hydrocarbons, siloxanes, and volatile halogenated hydrocarbons) over a 3-year period. Trace compounds entering the gas engines, their impact on the engine performance were evaluated. The operational problems included deposit formation in the combustion chamber, turbocharger, and intercooler of engine before the scheduled maintenance times. High levels of hydrogen sulfide, as well as chlorinated and fluorinated compounds cause corrosion of the engine parts and decrease life of the engine oils. Persistence of siloxanes results in deposit formation, increasing engine maintenance costs. Pretreatment of LFG is necessary to protect the engines at the waste-to-energy facilities with persistence levels of siloxanes and volatile halogenated hydrocarbons.

  6. Evaluation of a 2-MW carbonate fuel cell power plant fueled by landfill gas. Final report

    SciTech Connect

    Meade, D.B.; Selander, S.; Rastler, D.M.

    1991-11-01

    This project assessed the technical and economic feasibility of operating an atmospheric pressure 2 MW carbonate fuel cell power plant on landfill gas. A commercially available low pressure gas pre-treatment system was identified for this application. System simulation studies were performed to identify component bottle-necks which would limit power production, or preclude system operation. An economic assessment was conducted to assess the competitiveness of the fuel cell system. The analysis confirmed the technical feasibility of operating Energy Research Corporation`s 2MW fuel cell system on landfill gas. Resulting net electrical efficiency was 50% based on the fuel`s lower heating value. Plant capital cost increased by {approximately}$180/kw; this was primarily for gas cleanup. Bus bar power costs for market entry and commercial fuel cell plants were found to be competitive with power produced from baseload coal plants in Minnesota.

  7. Evaluation of a 2-MW carbonate fuel cell power plant fueled by landfill gas

    SciTech Connect

    Meade, D.B. ); Selander, S. ); Rastler, D.M. )

    1991-11-01

    This project assessed the technical and economic feasibility of operating an atmospheric pressure 2 MW carbonate fuel cell power plant on landfill gas. A commercially available low pressure gas pre-treatment system was identified for this application. System simulation studies were performed to identify component bottle-necks which would limit power production, or preclude system operation. An economic assessment was conducted to assess the competitiveness of the fuel cell system. The analysis confirmed the technical feasibility of operating Energy Research Corporation's 2MW fuel cell system on landfill gas. Resulting net electrical efficiency was 50% based on the fuel's lower heating value. Plant capital cost increased by {approximately}$180/kw; this was primarily for gas cleanup. Bus bar power costs for market entry and commercial fuel cell plants were found to be competitive with power produced from baseload coal plants in Minnesota.

  8. Greenhouse gas emissions during MSW landfilling in China: influence of waste characteristics and LFG treatment measures.

    PubMed

    Yang, Na; Zhang, Hua; Shao, Li-Ming; Lü, Fan; He, Pin-Jing

    2013-11-15

    Reducing greenhouse gas (GHG) emissions from municipal solid waste (MSW) treatment can be highly cost-effective in terms of GHG mitigation. This study investigated GHG emissions during MSW landfilling in China under four existing scenarios and in terms of seven different categories: waste collection and transportation, landfill management, leachate treatment, fugitive CH4 (FM) emissions, substitution of electricity production, carbon sequestration and N2O and CO emissions. GHG emissions from simple sanitary landfilling technology where no landfill gas (LFG) extraction took place (Scenario 1) were higher (641-998 kg CO2-eq·t(-1)ww) than those from open dump (Scenario 0, 480-734 kg CO2-eq·t(-1)ww). This was due to the strictly anaerobic conditions in Scenario 1. LFG collection and treatment reduced GHG emissions to 448-684 kg CO2-eq·t(-1)ww in Scenario 2 (with LFG flare) and 214-277 kg CO2-eq·t(-1)ww in Scenario 3 (using LFG for electricity production). Amongst the seven categories, FM was the predominant contributor to GHG emissions. Global sensitivity analysis demonstrated that the parameters associated with waste characteristics (i.e. CH4 potential and carbon sequestered faction) and LFG management (i.e. LFG collection efficiency and CH4 oxidation efficiency) were of great importance. A further learning on the MSW in China indicated that water content and dry matter content of food waste were the basic factors affecting GHG emissions. Source separation of food waste, as well as increasing the incineration ratio of mixed collected MSW, could effectively mitigate the overall GHG emissions from landfilling in a specific city. To increase the LFG collection and CH4 oxidation efficiencies could considerably reduce GHG emissions on the landfill site level. While, the improvement in the LFG utilization measures had an insignificant impact as long as the LFG is recovered for energy generation.

  9. Greenhouse gas reduction by recovery and utilization of landfill methane and CO{sub 2} technical and market feasibility study, Boului Landfill, Bucharest, Romania. Final report, September 30, 1997--September 19, 1998

    SciTech Connect

    Cook, W.J.; Brown, W.R.; Siwajek, L.; Sanders, W.I.; Botgros, I.

    1998-09-01

    The project is a landfill gas to energy project rated at about 4 megawatts (electric) at startup, increasing to 8 megawatts over time. The project site is Boului Landfill, near Bucharest, Romania. The project improves regional air quality, reduces emission of greenhouse gases, controls and utilizes landfill methane, and supplies electric power to the local grid. The technical and economic feasibility of pre-treating Boului landfill gas with Acrion`s new landfill gas cleanup technology prior to combustion for power production us attractive. Acrion`s gas treatment provides several benefits to the currently structured electric generation project: (1) increase energy density of landfill gas from about 500 Btu/ft{sup 3} to about 750 Btu/ft{sup 3}; (2) remove contaminants from landfill gas to prolong engine life and reduce maintenance;; (3) recover carbon dioxide from landfill gas for Romanian markets; and (4) reduce emission of greenhouse gases methane and carbon dioxide. Greenhouse gas emissions reduction attributable to successful implementation of the landfill gas to electric project, with commercial liquid CO{sub 2} recovery, is estimated to be 53 million metric tons of CO{sub 2} equivalent of its 15 year life.

  10. Catalytically upgraded landfill gas as a cost-effective alternative for fuel cells

    NASA Astrophysics Data System (ADS)

    Urban, W.; Lohmann, H.; Gómez, J. I. Salazar

    The potential use of landfill gas as feeding fuel for the so-called molten carbonate fuel cells (MCFC) imposes the need for new upgrading technologies in order to meet the much tougher feed gas specifications of this type of fuel cells in comparison to gas engines. Nevertheless, MCFC has slightly lower purity demands than low temperature fuel cells. This paper outlines the idea of a new catalytic purification process for landfill gas conditioning, which may be supposed to be more competitive than state-of-the-art technologies and summarises some lab-scale results. This catalytic process transforms harmful landfill gas minor compounds into products that can be easily removed from the gas stream by a subsequent adsorption step. The optimal process temperature was found to be in the range 250-400 °C. After a catalyst screening, two materials were identified, which have the ability to remove all harmful minor compounds from landfill gas. The first material was a commercial alumina that showed a high activity towards the removal of organic silicon compounds. The alumina protects both a subsequent catalyst for the removal of other organic minor compounds and the fuel cell. Due to gradual deactivation caused by silica deposition, the activated alumina needs to be periodically replaced. The second material was a commercial V 2O 5/TiO 2-based catalyst that exhibited a high activity for the total oxidation of a broad spectrum of other harmful organic minor compounds into a simpler compound class "acid gases (HCl, HF and SO 2)", which can be easily removed by absorption with, e.g. alkalised alumina. The encouraging results obtained allow the scale-up of this LFG conditioning process to test it under real LFG conditions.

  11. TESTING OF FUEL CELLS TO RECOVER ENERGY FROM LANDFILL GAS: GROTON LANDFILL

    EPA Science Inventory

    The report summarizes the results of follow-on tests following a four-phase EPA program. The environmental impact of widespread use of this concept would be a significant reduction of global warming gas emissions (methane and carbon dioxide). The follow-on testing, conducted by N...

  12. Gas permeability of biochar-amended clay: potential alternative landfill final cover material.

    PubMed

    Wong, James Tsz Fung; Chen, Zhongkui; Ng, Charles Wang Wai; Wong, Ming Hung

    2016-04-01

    Compacted biochar-amended clay (BAC) has been proposed as an alternative landfill final cover material in this study. Biochar has long been proposed to promote crop growth, mitigate odor emission, and promote methane oxidation in field soils. However, previous studies showed that soil-gas permeability was increased upon biochar application, which will promote landfill gas emission. The objective of the present study is to investigate the possibility of using compacted BAC as an alternative material in landfill final cover by evaluating its gas permeability. BAC samples were prepared by mixing 425-μm-sieved peanut shell biochar with kaolin clay in different ratios (0, 5, 10, and 15 %, w/w) and compacting at different degrees of compactions (DOC) (80, 85, and 90 %) with an optimum water content of 35 %. The gas permeability of the BACs was measured by flexible wall gas permeameter and the microstructure of the BACs was analyzed by SEM with energy-dispersive x-ray spectroscopy (EDX). The results show that the effects of biochar content on BAC gas permeability is highly dependent on the DOC. At high DOC (90 %), the gas permeability of BAC decreases with increasing biochar content due to the combined effect of the clay aggregation and the inhibition of biochar in the gas flow. However, at low DOC (80 %), biochar incorporation has no effects on gas permeability because it no longer acts as a filling material to the retard gas flow. The results from the present study imply that compacted BAC can be used as an alternative final cover material with decreased gas permeability when compared with clay.

  13. Gas permeability of biochar-amended clay: potential alternative landfill final cover material.

    PubMed

    Wong, James Tsz Fung; Chen, Zhongkui; Ng, Charles Wang Wai; Wong, Ming Hung

    2016-04-01

    Compacted biochar-amended clay (BAC) has been proposed as an alternative landfill final cover material in this study. Biochar has long been proposed to promote crop growth, mitigate odor emission, and promote methane oxidation in field soils. However, previous studies showed that soil-gas permeability was increased upon biochar application, which will promote landfill gas emission. The objective of the present study is to investigate the possibility of using compacted BAC as an alternative material in landfill final cover by evaluating its gas permeability. BAC samples were prepared by mixing 425-μm-sieved peanut shell biochar with kaolin clay in different ratios (0, 5, 10, and 15 %, w/w) and compacting at different degrees of compactions (DOC) (80, 85, and 90 %) with an optimum water content of 35 %. The gas permeability of the BACs was measured by flexible wall gas permeameter and the microstructure of the BACs was analyzed by SEM with energy-dispersive x-ray spectroscopy (EDX). The results show that the effects of biochar content on BAC gas permeability is highly dependent on the DOC. At high DOC (90 %), the gas permeability of BAC decreases with increasing biochar content due to the combined effect of the clay aggregation and the inhibition of biochar in the gas flow. However, at low DOC (80 %), biochar incorporation has no effects on gas permeability because it no longer acts as a filling material to the retard gas flow. The results from the present study imply that compacted BAC can be used as an alternative final cover material with decreased gas permeability when compared with clay. PMID:26092359

  14. Numerical modeling of landfill gas and heat transport in the deformable MSW landfill body. Part 2. Verification and application of the model

    NASA Astrophysics Data System (ADS)

    Kutsyi, D. V.

    2015-07-01

    The article is devoted to studying the parameters of wells that are used as part of vertical landfill gas collection systems for degassing landfills. To this end, the thermophysical model developed in the first part of this work is considered. The model is constructed using the initial data obtained at real dump and landfill with subsequently comparing the calculation results with the data of experimental measurements. A method for determining the average hydrodynamic properties of wastes is proposed, using which the heterogeneity of wastes can be taken into account. The effect the operating and design parameters of the well have on its performance is investigated on the basis of these properties. It has been determined that increasing the suction pressure, drilling diameter, and perforation height allows the well production rate to be increased by around 10%. The effect the increase of the well production rate has on the landfill gas collection project's payback period is demonstrated taking typical dump and landfill as an example.

  15. A CASE STUDY DEMONSTRATING GUIDANCE FOR EVALUATING LANDFILL GAS EMISSIONS FROM CLOSED OR ABANDONED FACILITIES--SOMERSWORTH, NEW HAMPSHIRE

    EPA Science Inventory

    The purpose of the activities described in this document is to provide a demonstration of the procedures and methodologies described within the "Guidance for Evaluating Landfill Gas Emissions from Closed or Abandoned Facilities" (Guidance). This demonstration provides an example ...

  16. Impact of intermittent aerations on leachate quality and greenhouse gas reduction in the aerobic-anaerobic landfill method.

    PubMed

    Nag, Mitali; Shimaoka, Takayuki; Komiya, Teppei

    2016-09-01

    The aerobic-anaerobic landfill method (AALM) is a novel approach in solid waste management that could shorten the landfill post-closure period and minimize the environmental loads. In this study, the aerobic-anaerobic landfill method was evaluated by using intermittent aeration. In addition, the nitrification-denitrification process was assessed as a means of reducing the emission of greenhouse gases (GHGs) and improving the leachate quality during the degradation of the organic solid waste. The leachate quality and the gas composition in each of the reactors were measured during the experimental period (408days). The aeration process entailed the injection of air into plexiglass cylinders (200cm height×10 cm diameter), filled with fresh organic solid waste collected from a composting plant. Different aeration routines were applied, namely, continuous aeration (aerobic reactor A), aeration for three days/week (aerobic-anaerobic reactor B), aeration for 6h/day (aerobic-anaerobic reactor C), and no aeration (non-aerated reactor D). It was found that aerobic reactor A produced the best results in terms of reduction of GHGs and improvement of the leachate quality. The aerobic-anaerobic reactor C was found to be more effective than reactor B in respect of both the emission of GHGs and the leachate quality; moreover, compared with aerobic reactor A, energy costs were reduced by operating this reactor. The transition period phenomenon was investigated during an intensive seven-day experiment conducted on the discharged leachate obtained from aerobic-anaerobic reactors B and C. The experiment concerned the differences in the composition of the gas during the aeration and the non-aeration periods. It was found that the transition period between the aeration and non-aeration cycles, which followed the simultaneous nitrification-denitrification had a considerable effect on the leachate quality of both the reactors. The results indicated that AALM has the potential to reduce

  17. Impact of intermittent aerations on leachate quality and greenhouse gas reduction in the aerobic-anaerobic landfill method.

    PubMed

    Nag, Mitali; Shimaoka, Takayuki; Komiya, Teppei

    2016-09-01

    The aerobic-anaerobic landfill method (AALM) is a novel approach in solid waste management that could shorten the landfill post-closure period and minimize the environmental loads. In this study, the aerobic-anaerobic landfill method was evaluated by using intermittent aeration. In addition, the nitrification-denitrification process was assessed as a means of reducing the emission of greenhouse gases (GHGs) and improving the leachate quality during the degradation of the organic solid waste. The leachate quality and the gas composition in each of the reactors were measured during the experimental period (408days). The aeration process entailed the injection of air into plexiglass cylinders (200cm height×10 cm diameter), filled with fresh organic solid waste collected from a composting plant. Different aeration routines were applied, namely, continuous aeration (aerobic reactor A), aeration for three days/week (aerobic-anaerobic reactor B), aeration for 6h/day (aerobic-anaerobic reactor C), and no aeration (non-aerated reactor D). It was found that aerobic reactor A produced the best results in terms of reduction of GHGs and improvement of the leachate quality. The aerobic-anaerobic reactor C was found to be more effective than reactor B in respect of both the emission of GHGs and the leachate quality; moreover, compared with aerobic reactor A, energy costs were reduced by operating this reactor. The transition period phenomenon was investigated during an intensive seven-day experiment conducted on the discharged leachate obtained from aerobic-anaerobic reactors B and C. The experiment concerned the differences in the composition of the gas during the aeration and the non-aeration periods. It was found that the transition period between the aeration and non-aeration cycles, which followed the simultaneous nitrification-denitrification had a considerable effect on the leachate quality of both the reactors. The results indicated that AALM has the potential to reduce

  18. Assessment of soil-gas, soil, and water contamination at the former hospital landfill, Fort Gordon, Georgia, 2009-2010

    USGS Publications Warehouse

    Falls, Fred W.; Caldwell, Andral W.; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2011-01-01

    Soil gas, soil, and water were assessed for organic and inorganic constituents at the former hospital landfill located in a 75-acre study area near the Dwight D. Eisenhower Army Medical Center, Fort Gordon, Georgia, from April to September 2010. Passive soil-gas samplers were analyzed to evaluate organic constituents in the hyporheic zone of a creek adjacent to the landfill and soil gas within the estimated boundaries of the former landfill. Soil and water samples were analyzed to evaluate inorganic constituents in soil samples, and organic and inorganic constituents in the surface water of a creek adjacent to the landfill, respectively. This assessment was conducted to provide environmental constituent data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Results from the hyporheic-zone assessment in the unnamed tributary adjacent to the study area indicated that total petroleum hydrocarbons and octane were the most frequently detected organic compounds in groundwater beneath the creek bed. The highest concentrations for these compounds were detected in the upstream samplers of the hyporheic-zone study area. The effort to delineate landfill activity in the study area focused on the western 14 acres of the 75-acre study area where the hyporheic-zone study identified the highest concentrations of organic compounds. This also is the part of the study area where a debris field also was identified in the southern part of the 14 acres. The southern part of this 14-acre study area, including the debris field, is steeper and not as heavily wooded, compared to the central and northern parts. Fifty-two soil-gas samplers were used for the July 2010 soil-gas survey in the 14-acre study area and mostly detected total petroleum hydrocarbons, and gasoline and diesel compounds. The highest soil-gas masses for total petroleum hydrocarbons, diesel compounds, and the only valid detection of perchloroethene

  19. Evaluating effects of wind-induced pressure fluctuations on soil-atmosphere gas exchange at a landfill using stochastic modelling.

    PubMed

    Poulsen, Tjalfe G; Møldrup, Per

    2006-10-01

    The impact of wind turbulence-induced pressure fluctuations at the soil surface on landfill gas transport and emissions to the atmosphere at an old Danish landfill site was investigated using stochastic modelling combined with soil property and gas transport data measured at the site. The impacts of soil physical properties (including air permeability and volumetric water content) and wind-induced pressure fluctuation properties (amplitude and temporal correlation) on landfill gas emissions to the atmosphere were evaluated. Soil-air permeability and pressure fluctuation amplitude were found to be the most important parameters. Wind-induced gas emissions were further compared with gas emissions caused by diffusion and by long-term pressure variations (due to passing weather systems). Here diffusion and wind-induced gas transport were found to be equally important with wind-induced gas transport becoming the most important at lower soil-air contents.

  20. Characterization of trichloroethylene adsorption onto waste biocover soil in the presence of landfill gas.

    PubMed

    He, Ruo; Su, Yao; Kong, Jiaoyan

    2015-09-15

    Waste biocover soils (WBS) have been demonstrated to have great potential in mitigating trichloroethylene (TCE) emission from landfills, due to the relatively high TCE-degrading capacity. In this study, the characteristics of TCE adsorption on WBS in the presence of the major landfill gas components (i.e., CH4 and CO2) were investigated in soil microcosms. The adsorption isotherm of TCE onto WBS was fitted well with linear model within the TCE concentrations of 7000 ppmv. The adsorption capacity of TCE onto WBS was affected by temperature, soil moisture content and particle size, of which, temperature was the dominant factor. The adsorption capacity of TCE onto the experimental materials increased with the increasing organic matter content. A significantly positive correlation was observed between the adsorption capacity of TCE and the organic matter content of experimental materials that had relatively higher organic content (r = 0.988, P = 0.044). To better understand WBS application in practice, response surface methodology was developed to predict TCE adsorption capacity and emissions through WBS in different landfills in China. These results indicated that WBS had high adsorption capacity of TCE in LFG and temperature should be paid more attention to manipulate WBS to reduce TCE emissions from landfills.

  1. Characterization of trichloroethylene adsorption onto waste biocover soil in the presence of landfill gas.

    PubMed

    He, Ruo; Su, Yao; Kong, Jiaoyan

    2015-09-15

    Waste biocover soils (WBS) have been demonstrated to have great potential in mitigating trichloroethylene (TCE) emission from landfills, due to the relatively high TCE-degrading capacity. In this study, the characteristics of TCE adsorption on WBS in the presence of the major landfill gas components (i.e., CH4 and CO2) were investigated in soil microcosms. The adsorption isotherm of TCE onto WBS was fitted well with linear model within the TCE concentrations of 7000 ppmv. The adsorption capacity of TCE onto WBS was affected by temperature, soil moisture content and particle size, of which, temperature was the dominant factor. The adsorption capacity of TCE onto the experimental materials increased with the increasing organic matter content. A significantly positive correlation was observed between the adsorption capacity of TCE and the organic matter content of experimental materials that had relatively higher organic content (r = 0.988, P = 0.044). To better understand WBS application in practice, response surface methodology was developed to predict TCE adsorption capacity and emissions through WBS in different landfills in China. These results indicated that WBS had high adsorption capacity of TCE in LFG and temperature should be paid more attention to manipulate WBS to reduce TCE emissions from landfills. PMID:25909498

  2. Strategies to Optimize Microbially-Mediated Mitigation of Greenhouse Gas Emissions from Landfill Cover Soils

    SciTech Connect

    Jeremy Semrau; Sung-Woo Lee; Jeongdae Im; Sukhwan Yoon; Michael Barcelona

    2010-09-30

    The overall objective of this project, 'Strategies to Optimize Microbially-Mediated Mitigation of Greenhouse Gas Emissions from Landfill Cover Soils' was to develop effective, efficient, and economic methodologies by which microbial production of nitrous oxide can be minimized while also maximizing microbial consumption of methane in landfill cover soils. A combination of laboratory and field site experiments found that the addition of nitrogen and phenylacetylene stimulated in situ methane oxidation while minimizing nitrous oxide production. Molecular analyses also indicated that methane-oxidizing bacteria may play a significant role in not only removing methane, but in nitrous oxide production as well, although the contribution of ammonia-oxidizing archaea to nitrous oxide production can not be excluded at this time. Future efforts to control both methane and nitrous oxide emissions from landfills as well as from other environments (e.g., agricultural soils) should consider these issues. Finally, a methanotrophic biofiltration system was designed and modeled for the promotion of methanotrophic activity in local methane 'hotspots' such as landfills. Model results as well as economic analyses of these biofilters indicate that the use of methanotrophic biofilters for controlling methane emissions is technically feasible, and provided either the costs of biofilter construction and operation are reduced or the value of CO{sub 2} credits is increased, can also be economically attractive.

  3. Analysis of microbial community structure and composition in leachates from a young landfill by 454 pyrosequencing.

    PubMed

    Köchling, Thorsten; Sanz, José Luis; Gavazza, Sávia; Florencio, Lourdinha

    2015-07-01

    Microorganisms are responsible for degrading the raw leachate generated in sanitary landfills, extracting the soluble fraction of the landfill waste and biotransforming organic matter and toxic residues. To increase our understanding of these highly contaminated ecosystems, we analyzed the microbial communities in the leachate produced by three landfill cells of different ages. Using high-throughput 454 pyrosequencing of the 16S rRNA gene, we describe the structure of the leachate communities and present their compositional characteristics. All three communities exhibited a high level of abundance but were undersampled, as indicated by the results of the rarefaction analysis. The distribution of the taxonomic operational units (OTUs) was highly skewed, suggesting a community structure with a few dominant members that are key for the degradation process and numerous rare microorganisms, which could act as a resilient microorganism seeder pool. Members of the phylum Firmicutes were dominant in all of the samples, accounting for up to 62% of the bacterial sequences, and their proportion increased with increasing landfill age. Other abundant phyla included Bacteroidetes, Proteobacteria, and Spirochaetes, which together with Firmicutes comprised 90% of the sequences. The data illustrate a microbial community that degrades organic matter in raw leachate in the early stages, before the methanogenic phase takes place. The genera found fit well into the classical pathways of anaerobic digestion processes. PMID:25652654

  4. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test.

    PubMed

    Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

    2013-10-01

    Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.

  5. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test.

    PubMed

    Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

    2013-10-01

    Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane. PMID:23684695

  6. Annual Performance Assessment and Composite Analysis Review for the ICDF Landfill FY 2008

    SciTech Connect

    Karen Koslow Arthur Rood

    2009-08-31

    This report addresses low-level waste disposal operations at the Idaho Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Disposal Facility (ICDF) landfill from the start of operations in Fiscal Year 2003 through Fiscal Year 2008. The ICDF was authorized in the Operable Unit 3-13 Record of Decision for disposal of waste from the Idaho National Laboratory Site CERCLA environmental restoration activities. The ICDF has been operating since 2003 in compliance with the CERCLA requirements and the waste acceptance criteria developed in the CERCLA process. In developing the Operable Unit 3-13 Record of Decision, U.S. Department of Energy Order (DOE) 435.1, 'Radioactive Waste Management', was identified as a 'to be considered' requirement for the ICDF. The annual review requirement under DOE Order 435.1 was determined to be an administrative requirement and, therefore, annual reviews were not prepared on an annual basis. However, the landfill has been operating for 5 years and, since the waste forms and inventories disposed of have changed from what was originally envisioned for the ICDF landfill, the ICDF project team has decided that this annual review is necessary to document the changes and provide a basis for any updates in analyses that may be necessary to continue to meet the substantive requirements of DOE Order 435.1. For facilities regulated under DOE Order 435.1-1, U.S. DOE Manual 435.1-1, 'Radioactive Waste Management', IV.P.(4)(c) stipulates that annual summaries of low-level waste disposal operations shall be prepared with respect to the conclusions and recommendations of the performance assessment and composite analysis. Important factors considered in this review include facility operations, waste receipts, and results from monitoring and research and development programs. There have been no significant changes in operations at the landfill in respect to the disposal geometry, the verification of waste characteristics, and the

  7. Comparison between landfill gas and waste incineration for power generation in Astana, Kazakhstan.

    PubMed

    Inglezakis, Vassilis J; Rojas-Solórzano, Luis; Kim, Jong; Aitbekova, Aisulu; Ismailova, Aizada

    2015-05-01

    The city of Astana, the capital of Kazakhstan, which has a population of 804,474, and has been experiencing rapid growth over the last 15 years, generates approximately 1.39 kg capita(-1) day(-1) of municipal solid waste (MSW). Nearly 700 tonnes of MSW are collected daily, of which 97% is disposed of at landfills. The newest landfill was built using modern technologies, including a landfill gas (LFG) collection system.The rapid growth of Astana demands more energy on its path to development, and the viability analysis of MSW to generate electricity is imperative. This paper presents a technical-economic pre-feasibility study comparing landfill including LFG utilization and waste incineration (WI) to produce electricity. The performance of LFG with a reciprocating engine and WI with steam turbine power technologies were compared through corresponding greenhouse gases (GHG) reduction, cost of energy production (CEP), benefit-cost ratio (BCR), net present value (NPV) and internal rate of return (IRR) from the analyses. Results demonstrate that in the city of Astana, WI has the potential to reduce more than 200,000 tonnes of GHG per year, while LFG could reduce slightly less than 40,000 tonnes. LFG offers a CEP 5.7% larger than WI, while the latter presents a BCR two times higher than LFG. WI technology analysis depicts a NPV exceeding 280% of the equity, while for LFG, the NPV is less than the equity, which indicates an expected remarkable financial return for the WI technology and a marginal and risky scenario for the LFG technology. Only existing landfill facilities with a LFG collection system in place may turn LFG into a viable project.

  8. Comparison between landfill gas and waste incineration for power generation in Astana, Kazakhstan.

    PubMed

    Inglezakis, Vassilis J; Rojas-Solórzano, Luis; Kim, Jong; Aitbekova, Aisulu; Ismailova, Aizada

    2015-05-01

    The city of Astana, the capital of Kazakhstan, which has a population of 804,474, and has been experiencing rapid growth over the last 15 years, generates approximately 1.39 kg capita(-1) day(-1) of municipal solid waste (MSW). Nearly 700 tonnes of MSW are collected daily, of which 97% is disposed of at landfills. The newest landfill was built using modern technologies, including a landfill gas (LFG) collection system.The rapid growth of Astana demands more energy on its path to development, and the viability analysis of MSW to generate electricity is imperative. This paper presents a technical-economic pre-feasibility study comparing landfill including LFG utilization and waste incineration (WI) to produce electricity. The performance of LFG with a reciprocating engine and WI with steam turbine power technologies were compared through corresponding greenhouse gases (GHG) reduction, cost of energy production (CEP), benefit-cost ratio (BCR), net present value (NPV) and internal rate of return (IRR) from the analyses. Results demonstrate that in the city of Astana, WI has the potential to reduce more than 200,000 tonnes of GHG per year, while LFG could reduce slightly less than 40,000 tonnes. LFG offers a CEP 5.7% larger than WI, while the latter presents a BCR two times higher than LFG. WI technology analysis depicts a NPV exceeding 280% of the equity, while for LFG, the NPV is less than the equity, which indicates an expected remarkable financial return for the WI technology and a marginal and risky scenario for the LFG technology. Only existing landfill facilities with a LFG collection system in place may turn LFG into a viable project. PMID:25819927

  9. Gas Transport Parameters for Landfill Cover Soils: Effects of Soil Compaction and Water Blockages

    NASA Astrophysics Data System (ADS)

    Wickramarachchi, P. N.; Hamamoto, S.; Kawamoto, K.; Nawagamuwa, U.; Komatsu, T.; Moldrup, P.

    2009-12-01

    Recently, landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric CH4. landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest source of anthropogenic CH4 emission , the final cover system should also be designed for minimizing the biogas migration into the atmosphere or the areas surrounding the landfill. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil , there are few studies about gas transport characteristics of landfill cover soils. Therefore, the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size and water blockage effects on the gas exchange in t highly compacted final cover soil are largely unknown. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport . In this study, the effects of compaction level and water blockage effects on ka and Dp for two landfill final cover soils were investigated. The disturbed soil samples were taken from landfill final covers in Japan and Sri Lanka. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm) at two different compaction levels (2700 kN/m2 and 600 kN/m2). After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential (pF; pF equals to log(-ɛ) where ɛ is soil-water matric potential in cm H2O) of 1.5, 2.0, 3.0, 4.1, and with air-dried (pF 6.0) and oven-dried (pF 6.9) conditions. Results showed that measured Dp values

  10. Evaluation of a biologically active cover for mitigation of landfill gas emissions.

    PubMed

    Barlaz, M A; Green, R B; Chanton, J P; Goldsmith, C D; Hater, G R

    2004-09-15

    Landfills are the third largest source of anthropogenic CH4 in the United States, and there is potential for reduction in this source of greenhouse gases and other contaminants. The objective of this work was to contrast emissions of CH4 and non-methane organic compounds (NMOCs) from landfill cells covered with soil or a biologically active cover consisting of yard waste compost. On the basis of four field campaigns over 14 months, CH4 emissions from the biocover (BC) varied from -1.73 to 1.33 g m(-2) d(-1), with atmospheric uptake measured in 52% of tests. BC emissions did not increase when the gas collection system was turned off. Uptake of atmospheric CH4 was measured in 54% of tests on the soil cover (SC) when the gas collection was system active and 12% when the gas collection system was off. Many (26%) relatively high fluxes (>15 g m(-2) d(-1)) were measured from the SC as were some dramatic effects due to deactivation of the gas collection system. In tests with positive emissions, stable isotope measurements showed that the BC and SC were responsible for oxidation of 55% and 21% of the CH4 reaching the bottom of the respective cover. Seven of the highest 10 NMOC emissions were measured in the SC, and 17 of 21 fluxes for speciated organic compounds were higher in the SC. The relationship between CH4, NMOC, and individual organic compound emissions suggested a correlation between CH4 and trace organic oxidation. BCs can reduce landfill gas emissions in the absence of a gas collection system and can serve as a polishing step in the presence of an active system.

  11. Linking landfill hydrology and leachate chemical composition at a controlled municipal landfill (Kåstrup, Denmark) using state-space analysis.

    PubMed

    Poulsen, Tjalfe G; Moldrup, Per; Sørensen, Kirsten; Hansen, Jens Aa

    2002-10-01

    Leachate production and composition data for a municipal landfill measured over a 25-year period was used to investigate important processes and parameters. Long-term leachate production could be satisfactorily predicted from a simple top-layer landfill hydrology model while short-term predictions were less accurate, likely due to water storage in the waste. State-space and multiple regression modelling were used to identify relations between different parameters. State-space models proved most accurate in fitting measured data, likely because temporal correlation between measurements is accounted for unlike multiple regression. State-space modelling showed that temporal correlation in leachate production must be taken into account and confirmed that water storage inside the landfill is important. Temporal correlation is also important when predicting pH and chloride concentrations but less so for BOD5 and NH3/NH4+concentrations. Leachate flow did in general not have a strong impact upon leachate composition, small effects were observed for Cl-, and NH3/NH4+ concentrations. It was also observed that the mass load of nitrogen from the landfill was strongly dependent upon leachate nitrogen (ammonia/ammonium) concentrations and to a lesser degree upon leachate flow rates. This study introduces state-space modelling in solid waste management as a powerful tool to identify governing parameters for hydrological and bio-chemical processes.

  12. Greenhouse gas emissions during MSW landfilling in China: influence of waste characteristics and LFG treatment measures.

    PubMed

    Yang, Na; Zhang, Hua; Shao, Li-Ming; Lü, Fan; He, Pin-Jing

    2013-11-15

    Reducing greenhouse gas (GHG) emissions from municipal solid waste (MSW) treatment can be highly cost-effective in terms of GHG mitigation. This study investigated GHG emissions during MSW landfilling in China under four existing scenarios and in terms of seven different categories: waste collection and transportation, landfill management, leachate treatment, fugitive CH4 (FM) emissions, substitution of electricity production, carbon sequestration and N2O and CO emissions. GHG emissions from simple sanitary landfilling technology where no landfill gas (LFG) extraction took place (Scenario 1) were higher (641-998 kg CO2-eq·t(-1)ww) than those from open dump (Scenario 0, 480-734 kg CO2-eq·t(-1)ww). This was due to the strictly anaerobic conditions in Scenario 1. LFG collection and treatment reduced GHG emissions to 448-684 kg CO2-eq·t(-1)ww in Scenario 2 (with LFG flare) and 214-277 kg CO2-eq·t(-1)ww in Scenario 3 (using LFG for electricity production). Amongst the seven categories, FM was the predominant contributor to GHG emissions. Global sensitivity analysis demonstrated that the parameters associated with waste characteristics (i.e. CH4 potential and carbon sequestered faction) and LFG management (i.e. LFG collection efficiency and CH4 oxidation efficiency) were of great importance. A further learning on the MSW in China indicated that water content and dry matter content of food waste were the basic factors affecting GHG emissions. Source separation of food waste, as well as increasing the incineration ratio of mixed collected MSW, could effectively mitigate the overall GHG emissions from landfilling in a specific city. To increase the LFG collection and CH4 oxidation efficiencies could considerably reduce GHG emissions on the landfill site level. While, the improvement in the LFG utilization measures had an insignificant impact as long as the LFG is recovered for energy generation. PMID:24018116

  13. Passive and active soil gas sampling at the Mixed Waste Landfill, Technical Area III, Sandia National Laboratories/New Mexico

    SciTech Connect

    McVey, M.D.; Goering, T.J.; Peace, J.L.

    1996-02-01

    The Environmental Restoration Project at Sandia National Laboratories, New Mexico is tasked with assessing and remediating the Mixed Waste Landfill in Technical Area III. The Mixed Waste Landfill is a 2.6 acre, inactive radioactive and mixed waste disposal site. In 1993 and 1994, an extensive passive and active soil gas sampling program was undertaken to identify and quantify volatile organic compounds in the subsurface at the landfill. Passive soil gas surveys identified levels of PCE, TCE, 1,1, 1-TCA, toluene, 1,1,2-trichlorotrifluoroethane, dichloroethyne, and acetone above background. Verification by active soil gas sampling confirmed concentrations of PCE, TCE, 1,1,1-TCA, and 1,1,2-trichloro-1,2,2-trifluoroethane at depths of 10 and 30 feet below ground surface. In addition, dichlorodifluoroethane and trichlorofluoromethane were detected during active soil gas sampling. All of the volatile organic compounds detected during the active soil gas survey were present in the low ppb range.

  14. Characterization of wood plastic composites made from landfill-derived plastic and sawdust: Volatile compounds and olfactometric analysis

    SciTech Connect

    Félix, Juliana S.; Domeño, Celia; Nerín, Cristina

    2013-03-15

    Graphical abstract: This work details the characterization of VOCs of WPC, produced from residual materials which would have landfills as current destination, and evaluates their odor profile. Highlights: ► More than 140 volatile compounds were identified in raw materials and WPC products. ► Markers were related to the thermal degradation, sawdust or coupling agents. ► WPC prototype showed a characteristic odor profile of burnt, sweet and wax-like. ► Aldehydes, carboxylic acids, ketones and phenols were odor descriptors of WPC. - Abstract: Application of wood plastic composites (WPCs) obtained from recycled materials initially intended for landfill is usually limited by their composition, mainly focused on release of volatile organic compounds (VOCs) which could affect quality or human safety. The study of the VOCs released by a material is a requirement for new composite materials. Characterization and quantification of VOCs of several WPC produced with low density polyethylene (LDPE) and polyethylene/ethylene vinyl acetate (PE/EVA) films and sawdust were carried out, in each stage of production, by solid phase microextraction in headspace mode (HS-SPME) and gas chromatography–mass spectrometry (GC–MS). An odor profile was also obtained by HS-SPME and GC–MS coupled with olfactometry analysis. More than 140 compounds were observed in the raw materials and WPC samples. Some quantified compounds were considered WPC markers such as furfural, 2-methoxyphenol, N-methylphthalimide and 2,4-di-tert-butylphenol. Hexanoic acid, acetic acid, 2-methoxyphenol, acetylfuran, diacetyl, and aldehydes were the most important odorants. None of the VOCs were found to affect human safety for use of the WPC.

  15. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test

    SciTech Connect

    Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

    2013-10-15

    Highlights: • Equilibrium test was attempted to evaluate adsorption characteristics of siloxane. • L2 had higher removal efficiency in carbon compared to noncarbon adsorbents. • Total adsorption capacity of siloxane was 300 mg/g by coal activated carbon. • Adsorption characteristics rely on size of siloxane molecule and adsorbent pore. • Conversion of siloxane was caused by adsorption of noncarbon adsorbents. - Abstract: Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.

  16. Improved methodology to assess modification and completion of landfill gas management in the aftercare period

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Municipal solid waste landfills represent the dominant option for waste disposal in many parts of the world. While some countries have greatly reduced their reliance on landfills, there remain thousands of landfills that require aftercare. The development of cost-effective strategies for landfill af...

  17. Radiolytic Bubble Gas Hydrogen Compositions

    SciTech Connect

    Hester, J.R.

    2003-02-05

    Radioactive waste solids can trap bubbles containing hydrogen that may pose a flammability risk if they are disturbed and hydrogen is released. Whether a release is a problem or not depends, among other things, on the hydrogen composition of the gas. This report develops a method for estimating the hydrogen composition of trapped bubbles based on waste properties.

  18. Radiolytic Bubble Gas Hydrogen Compositions

    SciTech Connect

    Hester, J.R.

    2001-08-28

    Radioactive waste solids can trap bubbles containing hydrogen that may pose a flammability risk if they are disturbed and hydrogen is released. Whether a release is a problem or not depends, among other things, on the hydrogen composition of the gas. This report develops a method for estimating the hydrogen composition of trapped bubbles based on waste properties.

  19. The estimation of methane emissions from landfills with different cover systems

    NASA Astrophysics Data System (ADS)

    Park, S.; Lee, K.; Sung, K.

    2006-12-01

    Methane is a very potent greenhouse gas, second only to CO2 as an anthropogenic contributor to global warming. Landfills are important anthropogenic source in the CH4 emissions. Microbially mediated CH4 oxidation in landfills with conventional soil covers can serve as an efficient biological sink. Methane from modern sanitary landfills equipped with composite covers and gas collection system is vented directly to the atmosphere, except for some of the largest landfills at which it is collected and burned. However, previous laboratory research has shown that biofilters have the potential to reduce CH4 emissions from landfills with modern composite covers. In this study a CH4 emission model was developed. The model used the calculated CH4 oxidation rates to estimate CH4 emissions from landfills constructed with conventional soil covers, modern composite covers, and modern composite covers plus biofilters. According to the CH4 emission rates predicted by CH4 emission model, it was estimated that 90% of the generated CH4 was emitted to the atmosphere for landfills with modern composite cover. For landfills with modern composite cover plus biofilters, an average of only 9% of the generated CH4 was estimated to be emitted. For landfills with conventional covers, an average of 83% of the generated CH4 was estimated to be emitted. By comparing the CH4 emission rates from three different landfill types, the use of a properly managed biofilter should be an effective technique to reduce CH4 emissions from landfills.

  20. Characterization of wood plastic composites made from landfill-derived plastic and sawdust: volatile compounds and olfactometric analysis.

    PubMed

    Félix, Juliana S; Domeño, Celia; Nerín, Cristina

    2013-03-01

    Application of wood plastic composites (WPCs) obtained from recycled materials initially intended for landfill is usually limited by their composition, mainly focused on release of volatile organic compounds (VOCs) which could affect quality or human safety. The study of the VOCs released by a material is a requirement for new composite materials. Characterization and quantification of VOCs of several WPC produced with low density polyethylene (LDPE) and polyethylene/ethylene vinyl acetate (PE/EVA) films and sawdust were carried out, in each stage of production, by solid phase microextraction in headspace mode (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). An odor profile was also obtained by HS-SPME and GC-MS coupled with olfactometry analysis. More than 140 compounds were observed in the raw materials and WPC samples. Some quantified compounds were considered WPC markers such as furfural, 2-methoxyphenol, N-methylphthalimide and 2,4-di-tert-butylphenol. Hexanoic acid, acetic acid, 2-methoxyphenol, acetylfuran, diacetyl, and aldehydes were the most important odorants. None of the VOCs were found to affect human safety for use of the WPC. PMID:23259974

  1. Removal of hydrogen sulfide gas and landfill leachate treatment using coal bottom ash.

    PubMed

    Lin, C Y; Hesu, P H; Yang, D H

    2001-06-01

    Coal bottom ashes produced from three thermal power plants were used in column and batch experiments to investigate the adsorption capacity of the coal ash. Hydrogen sulfide and leachates collected from three sanitary landfill sites were used as adsorbate gas and solutions, respectively. Experimental results showed that coal bottom ash could remove H2S from waste gas or reduce the concentrations of various pollutants in the leachate. Each gram of bottom ash could remove up to 10.5 mg of H2S. In treating the landfill leachate, increasing ash dosage increased the removal efficiency but decreased the adsorption amount per unit mass of ash. For these tested ashes, the removal efficiencies of chemical oxygen demand (COD), NH3-N, total Kjeldhal nitrogen (TKN), P, Fe3+, Mn2+, and Zn2+ were 36.4-50, 24.2-39.4, 27.0-31.1, 82.2-92.9, 93.8-96.5, 93.7-95.4, and 80.5-82.2%, respectively; the highest adsorption capacities for those parameters were 3.5-5.6, 0.22-0.63, 0.36-0.45, 0.027-0.034, 0.050-0.053, 0.029-0.032, and 0.006 mg/g of bottom ash, respectively. The adsorption of pollutants in the leachate conformed to Freundlich's adsorption model.

  2. Assessment of soil-gas contamination at the 17th Street landfill, Fort Gordon, Georgia, 2011

    USGS Publications Warehouse

    Falls, W. Fred; Caldwell, Andral W.; Guimaraes, Wladmir G.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2012-01-01

    Assessments of contaminants in soil gas were conducted in two study areas at Fort Gordon, Georgia, in July and August of 2011 to supplement environmental contaminant data for previous studies at the 17th Street landfill. The two study areas include northern and eastern parts of the 17th Street landfill and the adjacent wooded areas to the north and east of the landfill. These study areas were chosen because of their close proximity to the surface water in Wilkerson Lake and McCoys Creek. A total of 48 soil-gas samplers were deployed for the July 28 to August 3, 2011, assessment in the eastern study area. The assessment mostly identified detections of total petroleum hydrocarbons (TPH), and gasoline- and diesel-range compounds, but also identified the presence of chlorinated solvents in six samplers, chloroform in three samplers, 2-methyl naphthalene in one sampler, and trimethylbenzene in one sampler. The TPH masses exceeded 0.02 microgram (μg) in all 48 samplers and exceeded 0.9 μg in 24 samplers. Undecane, one of the three diesel-range compounds used to calculate the combined mass for diesel-range compounds, was detected in 17 samplers and is the second most commonly detected compound in the eastern study area, exceeded only by the number of TPH detections. Six samplers had detections of toluene, but other gasoline compounds were detected with toluene in three of the samplers, including detections of ethylbenzene, meta- and para-xylene, and octane. All detections of chlorinated organic compounds had soil-gas masses equal to or less than 0.08 μg, including three detections of trichloroethene, three detections of perchloroethene, three chloroform detections, one 1,4-dichlorobenzene detection, and one 1,1,2-trichloroethane detection. Three methylated compounds were detected in the eastern study area, but were detected at or below method detection levels. A total of 32 soil-gas samplers were deployed for the August 11–24, 2011, assessment in the northern study

  3. Assessment of soil-gas and groundwater contamination at the Gibson Road landfill, Fort Gordon, Georgia, 2011

    USGS Publications Warehouse

    Falls, W. Fred; Caldwell, Andral W.; Guimaraes, Wladmir G.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2012-01-01

    Soil-gas and groundwater assessments were conducted at the Gibson Road landfill in 201 to provide screening-level environmental contamination data to supplement the data collected during previous environmental studies at the landfill. Passive samplers were used in both assessments to detect volatile and semivolatile organic compounds and polycyclic aromatic hydrocarbons in soil gas and groundwater. A total of 56 passive samplers were deployed in the soil in late July and early August for the soil-gas assessment. Total petroleum hydrocarbons (TPH) were detected at masses greater than the method detection level of 0.02 microgram in all samplers and masses greater than 2.0 micrograms in 13 samplers. Three samplers located between the landfill and a nearby wetland had TPH masses greater than 20 micrograms. Diesel was detected in 28 of the 56 soil-gas samplers. Undecane, tridecane, and pentadecane were detected, but undecane was the most common diesel compound with 23 detections. Only five detections exceeded a combined diesel mass of 0.10 microgram, including the highest mass of 0.27 microgram near the wetland. Toluene was detected in only five passive samplers, including masses of 0.65 microgram near the wetland and 0.85 microgram on the southwestern side of the landfill. The only other gasoline-related compound detected was octane in two samplers. Naphthalene was detected in two samplers in the gully near the landfill and two samplers along the southwestern side of the landfill, but had masses less than or equal to 0.02 microgram. Six samplers located southeast of the landfill had detections of chlorinated compounds, including one perchloroethene detections (0.04 microgram) and five chloroform detections (0.05 to0.08 microgram). Passive samplers were deployed and recovered on August 8, 2011, in nine monitoring wells along the southwestern, southeastern and northeastern sides of the landfill and down gradient from the eastern corner of the landfill. Six of the nine

  4. Measurements of methane emissions from landfills using mobile plume method with trace gas and cavity ring-down spectroscopy

    NASA Astrophysics Data System (ADS)

    Mønster, J.; Kjeldsen, P.; Scheutz, C.

    2012-04-01

    Methane is emitted to the atmosphere from both anthropogenic and natural sources. One of the major anthropogenic sources is methane produced by bacteria in anaerobic environments such as rice pads and landfills. Land filling has for many years been the preferred waste disposal method, resulting in a large methane production with a large contribution to the global increase in atmospheric green house gas concentration. Several steps have been taken to reduce the emission of methane from landfills. In order to validate the effect of these steps, a measurement method is needed to quantify methane emissions with a large spatial variation. One method is to use a highly sensitive and fast analytical method, capable of measuring the atmospheric concentration methane downwind from emission areas. Combined with down-wind measurements of a trace gas, emitted at a controlled mass flow rate, the methane emission can be calculated. This method is called the mobile plume method, as the whole plume is measured by doing several transects. In the current study a methane/acetylene analyzer with cavity ring-down spectroscopy detection (Picarro, G2203) was used to estimate methane from a number of Danish landfills. We measured at both active and closed landfills and investigated the difference in methane emission. At landfills where the emissions could have more than one origin, the source strength of the different emission areas was determined by accurate trace gas positioning and choosing appropriate wind speed and measurement distance. To choose these factors, we addressed the uncertainties and limitations of the method with respect to the configuration of the trace gas bottles and the distance between the emission area and the measurement points. Composting of organic material in large piles was done at several of the investigated landfills and where possible, the methane emission from this partly anaerobic digestion was measured as a separate emission.

  5. Is biodegradability a desirable attribute for discarded solid waste? Perspectives from a national landfill greenhouse gas inventory model.

    PubMed

    Levis, James W; Barlaz, Morton A

    2011-07-01

    There is increasing interest in the use of biodegradable materials because they are believed to be "greener". In a landfill, these materials degrade anaerobically to form methane and carbon dioxide. The fraction of the methane that is collected can be utilized as an energy source and the fraction of the biogenic carbon that does not decompose is stored in the landfill. A landfill life-cycle model was developed to represent the behavior of MSW components and new materials disposed in a landfill representative of the U.S. average with respect to gas collection and utilization over a range of environmental conditions (i.e., arid, moderate wet, and bioreactor). The behavior of materials that biodegrade at relatively fast (food waste), medium (biodegradable polymer) and slow (newsprint and office paper) rates was studied. Poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (PHBO) was selected as illustrative for an emerging biodegradable polymer. Global warming potentials (GWP) of 26, 720, -1000, 990, and 1300 kg CO(2)e wet Mg(-1) were estimated for MSW, food waste, newsprint, office paper, and PHBO, respectively in a national average landfill. In a state-of-the-art landfill with gas collection and electricity generation, GWP's of -250, 330, -1400, -96, and -420 kg CO(2)e wet Mg(-1) were estimated for MSW, food waste, newsprint, office paper and PHBO, respectively. Additional simulations showed that for a hypothetical material, a slower biodegradation rate and a lower extent of biodegradation improve the environmental performance of a material in a landfill representative of national average conditions.

  6. Is biodegradability a desirable attribute for discarded solid waste? Perspectives from a national landfill greenhouse gas inventory model.

    PubMed

    Levis, James W; Barlaz, Morton A

    2011-07-01

    There is increasing interest in the use of biodegradable materials because they are believed to be "greener". In a landfill, these materials degrade anaerobically to form methane and carbon dioxide. The fraction of the methane that is collected can be utilized as an energy source and the fraction of the biogenic carbon that does not decompose is stored in the landfill. A landfill life-cycle model was developed to represent the behavior of MSW components and new materials disposed in a landfill representative of the U.S. average with respect to gas collection and utilization over a range of environmental conditions (i.e., arid, moderate wet, and bioreactor). The behavior of materials that biodegrade at relatively fast (food waste), medium (biodegradable polymer) and slow (newsprint and office paper) rates was studied. Poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (PHBO) was selected as illustrative for an emerging biodegradable polymer. Global warming potentials (GWP) of 26, 720, -1000, 990, and 1300 kg CO(2)e wet Mg(-1) were estimated for MSW, food waste, newsprint, office paper, and PHBO, respectively in a national average landfill. In a state-of-the-art landfill with gas collection and electricity generation, GWP's of -250, 330, -1400, -96, and -420 kg CO(2)e wet Mg(-1) were estimated for MSW, food waste, newsprint, office paper and PHBO, respectively. Additional simulations showed that for a hypothetical material, a slower biodegradation rate and a lower extent of biodegradation improve the environmental performance of a material in a landfill representative of national average conditions. PMID:21615182

  7. PRESENT AND LONG-TERM COMPOSITION OF MSW LANDFILL LEACHATE: A REVIEW. (R827580)

    EPA Science Inventory

    The major potential environmental impacts related to landfill leachate are pollution of groundwater and surface waters. Landfill leachate contains pollutants that can be categorized into four groups (dissolved organic matter, inorganic macrocomponents, heavy metals, and xenobi...

  8. Using a Gas-Phase Tracer Test to Characterize the Impact of Landfill Gas Generation on Advective-Dispersive Transport of VOCs in the Vadose Zone

    PubMed Central

    Monger, Gregg R.; Duncan, Candice Morrison; Brusseau, Mark L.

    2015-01-01

    A gas-phase tracer test (GTT) was conducted at a landfill in Tucson, AZ, to help elucidate the impact of landfill gas generation on the transport and fate of chlorinated aliphatic volatile organic contaminants (VOCs). Sulfur hexafluoride (SF6) was used as the non-reactive gas tracer. Gas samples were collected from a multiport monitoring well located 15.2 m from the injection well, and analyzed for SF6, CH4, CO2, and VOCs. The travel times determined for SF6 from the tracer test are approximately two to ten times smaller than estimated travel times that incorporate transport by only gas-phase diffusion. In addition, significant concentrations of CH4 and CO2 were measured, indicating production of landfill gas. Based on these results, it is hypothesized that the enhanced rates of transport observed for SF6 are caused by advective transport associated with landfill gas generation. The rates of transport varied vertically, which is attributed to multiple factors including spatial variability of water content, refuse mass, refuse permeability, and gas generation. PMID:26380532

  9. Evaluation of aerated biofilter systems for microbial methane oxidation of poor landfill gas.

    PubMed

    Haubrichs, R; Widmann, R

    2006-01-01

    In the long-term, landfills are producing landfill gas (LFG) with low calorific values. Therefore, the utilization of LFG in combined heat and power plants (CHP) is limited to a certain period of time. A feasible method for LFG treatment is microbial CH(4) oxidation. Different materials were tested in actively aerated lab-scale bio-filter systems with a volume of 0.167 m(3). The required oxygen for the microbial CH(4) oxidation was provided through perforated probes, which distributed ambient air into the filter material. Three air input levels were installed along the height of the filter, each of them adjusted to a particular flow rate. During the tests, stable degradation rates of around 28 g/(m(3) h) in a fine-grained compost material were observed at a CH(4) inlet concentration of 30% over a period of 148 days. Compared with passive (not aerated) tests, the CH(4) oxidation rate increased by a factor of 5.5. Therefore, the enhancement of active aeration on the microbial CH(4) oxidation was confirmed. At a O(2)/CH(4) ratio of 2.5, nearly 100% of the CH(4) load was decomposed. By lowering the ratio from 2.5 to 2, the efficiency fell to values from 88% to 92%. By varying the distribution to the three air input levels, the CH(4) oxidation process was spread more evenly over the filter volume. PMID:16386886

  10. Evaluation of aerated biofilter systems for microbial methane oxidation of poor landfill gas.

    PubMed

    Haubrichs, R; Widmann, R

    2006-01-01

    In the long-term, landfills are producing landfill gas (LFG) with low calorific values. Therefore, the utilization of LFG in combined heat and power plants (CHP) is limited to a certain period of time. A feasible method for LFG treatment is microbial CH(4) oxidation. Different materials were tested in actively aerated lab-scale bio-filter systems with a volume of 0.167 m(3). The required oxygen for the microbial CH(4) oxidation was provided through perforated probes, which distributed ambient air into the filter material. Three air input levels were installed along the height of the filter, each of them adjusted to a particular flow rate. During the tests, stable degradation rates of around 28 g/(m(3) h) in a fine-grained compost material were observed at a CH(4) inlet concentration of 30% over a period of 148 days. Compared with passive (not aerated) tests, the CH(4) oxidation rate increased by a factor of 5.5. Therefore, the enhancement of active aeration on the microbial CH(4) oxidation was confirmed. At a O(2)/CH(4) ratio of 2.5, nearly 100% of the CH(4) load was decomposed. By lowering the ratio from 2.5 to 2, the efficiency fell to values from 88% to 92%. By varying the distribution to the three air input levels, the CH(4) oxidation process was spread more evenly over the filter volume.

  11. Assessing the performance of gas collection systems in select Chinese landfills according to the LandGEM model: drawbacks and potential direction.

    PubMed

    Sun, Yue; Yue, Dongbei; Li, Rundong; Yang, Ting; Liu, Shiliang

    2015-01-01

    In China, municipal solid waste (MSW) is primarily treated by landfilling. Landfill gas (LFG) collection effectively reduces methane emission from MSW landfills. An accurate system of LFG collection is important in landfill planning, design, and operation. However, China has not developed such systems. In this study, the efficiency of methane collection is calculated in three Chinese landfills with different collection systems (A: vertical wells for MSW before 2010; combined horizontal trenches and under-membrane pipes for MSW from 2011 onwards; B: combined horizontal trenches and vertical wells; C: vertical wells only). This efficiency was computed by dividing the quantity of methane obtained from landfill operation records by the quantity estimated based on the LandGEM model. Results show that the collection efficiencies of landfills with vertical wells and/or horizontal pipes ranged from 8.3% to 27.9%, whereas those of a system equipped with geomembrane reached 65.3%. The poor performance of the landfills was attributed to the open burning of early-stage LFG, LFG release from cracks in high-density polyethylene covers, and high levels of leachate within a landfill site. Therefore, this study proposes an integrated LFG collection system that can remove leachate and collect gas from landfills that accept waste with high moisture content. PMID:26510610

  12. Composition of bacterial and archaeal communities during landfill refuse decomposition processes.

    PubMed

    Song, Liyan; Wang, Yangqing; Zhao, Heping; Long, David T

    2015-12-01

    Little is known about the archaeal and the bacterial diversities in a landfill during different phases of decomposition. In this study, the archaeal and the bacterial diversities of Laogang landfill (Shanghai, China) at two different decomposition phases (i.e., initial methanogenic phase (IMP) and stable methanogenic phase (SMP)), were culture-independently examined using PCR-based 454 pyrosequencing. A total of 47,753 sequences of 16S rRNA genes were retrieved from 69,954 reads and analyzed to evaluate the diversities of the archaeal and bacterial communities. The most predominant types of archaea were hydrogenotrophic Methanomicrobiales, and of bacteria were Proteobacteria, Firmicutes, and Bacteroidetes. As might be expected, their abundances varied at decomposition phases. Archaea Methanomicrobiales accounts for 97.6% of total archaeal population abundance in IMP and about 57.6% in SMP. The abundance of archaeal genus Halobacteriale was 0.1% in IMP and was 20.3% in the SMP. The abundance of Firmicutes was 21.3% in IMP and was 4.3% in SMP. The abundance of Bacteroidetes represented 11.5% of total bacterial in IMP and was dominant (49.4%) in SMP. Both the IMP and SMP had unique cellulolytic bacteria compositions. IMP consisted of members of Bacillus, Fibrobacter, and Eubacterium, while SMP harbored groups of Microbacterium. Both phases had Clostridium with different abundance, 4-5 folds higher in SMP.

  13. A CASE STUDY DEMONSTRATING GUIDANCE FOR EVALUATING LANDFILL GAS EMISSIONS FROM CLOSED OR ABANDONED FACILITIES--SOUTH KINGSTOWN, RHODE ISLAND

    EPA Science Inventory

    The report describes a case study that applies EPA/600/R-05/123a, the guidance for conducting air pathway analyses of landfill gas emissions that are of interest to superfund remedial project managers, on-scene coordinators, facility owners, and potentially responsible parties. T...

  14. Greenhouse gas emissions from two-stage landfilling of municipal solid waste

    NASA Astrophysics Data System (ADS)

    Zhang, Yuanyuan; Yue, Dongbei; Nie, Yongfeng

    2012-08-01

    Simulations were conducted to investigate greenhouse gas emissions from aerobic pretreatment and subsequent landfilling. The flows in carbon balance, such as gas, leachate, and solid phases, were considered in the simulations. The total amount of CO2 eq. decreased as organic removal efficiency (ORE) increased. At ORE values of 0, 0.30, 0.41, and 0.54, the total amounts of CO2 eq. were 2614, 2326, 2075, and 1572 kg CO2 eq. per one ton dry matter, respectively; gas accounted for the main contribution to the total amount. The reduction in CO2 eq. from leachate was the primary positive contribution, accounting for 356%, 174%, and 100% of total reduction at ORE values of 0.30, 0.41, and 0.54, respectively. The CO2 eq. from energy consumption was the negative contribution to total reduction, but this contribution is considerably lower than that from gas. Aerobic pretreatment shortened the lag time of biogas production by 74.1-97.0%, and facilitated the transfer of organic carbon in solid waste from uncontrolled biogas and highly polluting leachate to aerobically generated CO2.

  15. In-Situ Quantification of Methanotrophic Activity in a Landfill Cover Soil Using Gas Push-Pull Tests

    NASA Astrophysics Data System (ADS)

    Gomez, K. E.; Gonzalez-Gil, G.; Schroth, M. H.; Zeyer, J.

    2007-12-01

    Landfills are both a major anthropogenic source and a sink for the greenhouse gas CH4. Methanogenic bacteria produce CH4 during the anaerobic digestion of landfill waste, whereas, methanotrophic bacteria consume CH4 as it is transported through a landfill cover soil. Methanotrophs are thought to be ubiquitous in soils, but typically exist in large numbers at oxic/anoxic interfaces, close to anaerobic methane sources but exposed to oxygen required for metabolism. Accurate in-situ quantification of the sink strength of methanotrophs in landfill cover soils is needed for global carbon balances and for local emissions mitigation strategies. We measured in-situ CH4 concentrations at 30, 60, and 100 cm depth at 18 evenly spaced locations across a landfill cover soil. Furthermore, we performed Gas Push-Pull Tests (GPPTs) to estimate in-situ rates of methanotrophic activity in the cover soil. The GPPT is a gas-tracer test in which a gas mixture containing CH4, O2, and non-reactive tracer gases is injected (pushed) into the soil followed by extraction (pull) from the same location. Quantification of CH4 oxidation rates is based upon comparison of the breakthrough curves of CH4 and tracer gases. We present the results of a series of GPPTs conducted at two locations in the cover soil to assess the feasibility and reproducibility of this technique to quantify methanotrophic activity. Additional GPPTs were performed with a methanotrophic inhibitor in the injection gas mixture to confirm the appropriate choice of tracers to quantify CH4 oxidation. Estimated CH4 oxidation rate constants indicate that the cover soil contains a highly active methanotrophic community.

  16. Integrated Cryogenic System for CO2 Separation and Lng Production from Landfill Gas

    NASA Astrophysics Data System (ADS)

    Chang, H. M.; Chung, M. J.; Park, S. B.

    2010-04-01

    An integrated cryogenic system to separate carbon dioxide (CO2) and produce LNG from landfill gas is investigated and designed. The main objective of this design is to eliminate the requirement of a standard CO2 removal process in the liquefaction system such distillation or (temperature or pressure) swing adsorption, and to directly separate carbon dioxide as frost at the liquefying channel of methane. Two identical sets of heat exchangers are installed in parallel and switched alternatively with a time period so that one is in separation-liquefaction mode while the other is in CO2 clean-up mode. A thermal regeneration scheme is presented for the purpose of saving energy and avoiding the stoppage of LNG production followed by the flow switching. The switching period is determined from results of a combined heat and mass transfer analysis on the CO2 freeze-out process.

  17. Assessment of soil-gas, soil, and water contamination at the former 19th Street landfill, Fort Gordon, Georgia, 2009-2010

    USGS Publications Warehouse

    Falls, W. Fred; Caldwell, Andral W.; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2011-01-01

    the creek. However, most TPH detections were located in and immediately adjacent to a debris field located within the former landfill and in areas where debris was not visible, including the northwestern and southeastern parts of the study area. Two of the four soil-gas samplers installed within a former military training area adjacent to the landfill also had TPH detections above the method detection level. Benzene, toluene, ethylbenzene, and xylene (as combined BTEX mass) were detected at 0.02 microgram or greater in three soil-gas samplers installed at the northwestern boundary and in five samplers installed in the southeastern part of the study area. There was no BTEX mass detected above the method detection level in samplers installed in the debris field. Toluene was the most frequently detected BTEX compound. Compounds indicative of diesel-range organics were detected above 0.04 microgram in 12 soil-gas samplers and had a distribution similar to that of TPH, including being detected in the debris field. Undecane was the most frequently detected diesel compound. Chloroform and naphthalene were detected in eight and two soil-gas samplers, respectively. Five soil-gas samplers deployed during September 2010 were analyzed for organic compounds classified as chemical agents and explosives, but none exceeded the method detection levels. Five composite soil samples collected from within the estimated boundaries of the former landfill were analyzed for 35 inorganic constituents, but none of the constituents detected exceeded regional screening levels for industrial soils. The sample collected in the debris field exceeded background levels for aluminum, barium, calcium, chromium, lead, nickel, potassium, sodium, and zinc. Three surface-water samples were collected in September 2010 from a stormwater outfall culvert that drains to the creek and from the open channel of the creek at upstream and downstream locations relative to the outfall. Toluene was detected at 0.661 mi

  18. Hydraulic permeability of bentonite-polymer composites for application in landfill technology

    NASA Astrophysics Data System (ADS)

    Dehn, Hanna; Haase, Hanna; Schanz, Tom

    2015-04-01

    Bentonites are often used as barrier materials in landfill technology to prevent infiltration of leachates to the natural environment. Since decades, geoenvironmental engineering aims at improving the hydro-mechanical performance of landfill liners. Various studies on the permeability performance of geosynthetic clay liners (GCLs) show effects of non-standard liquids on behaviour of Na+-bentonite regarding its sealing capacity. With increasing concentration of chemical aggressive solutions the sealing capacity decreases (Shackelford et al. 2000). An opportunity to improve the hydraulic permeability of the bentonites is the addition of polymers. The changes in hydraulic permeability performance of polymer treated and untreated bentonites while adding chemical aggressive solutions were studied by several authors. Results obtained by Scalia et al. (2014) illustrate that an increase in permeability can be prevented by adding polymer to Na+-bentonite. On the other hand, Ashmawy et al. (2002) presented results on the incapability of several commercial bentonite-polymer-products. The objective of this study is to characterize the influence of polymer addition on hydraulic performance of Na+-bentonite systematically. Therefore, the influence of 1% polymer addition of cationic and anionic polyacrylamide on the swelling pressure and hydraulic permeability of MX 80 bentonite was investigated. Preparation of bentonite-polymer composites was conducted (1) in dry conditions and (2) using solution-intercalation method. Experiments on hydraulic permeability were carried out using distilled water as well as CaCl2-solution. References Ashmawy, A. K., El-Hajji, D., Sotelo, N. & Muhammad, N. (2002), `Hydraulic Performance of Untreated and Polymer-treated Bentonite in Inorganic Landfill Leachates', Clays and Clay Minerals 50(5), 546-552. Scalia, J., Benson, C., Bohnhoff, G., Edil, T. & Shackelford, C. (2014), 'Long-Term Hydraulic Conductivity of a Bentonite-Polymer Composite Permeated

  19. Influence of mechanical-biological waste pre-treatment methods on the gas formation in landfills

    SciTech Connect

    Bockreis, A. . E-mail: a.bockreis@iwar.tu-darmstadt.de; Steinberg, I.

    2005-07-01

    In order to minimise emissions and environmental impacts, only pre-treated waste should be disposed of. For the last six years, a series of continuous experiments has been conducted at the Institute WAR, TU Darmstadt, in order to determine the emissions from pre-treated waste. Different kinds of pre-treated waste were incubated in several reactors and various data, including production and composition of the gas and the leachate, were collected. In this paper, the interim results of gas production and the gas composition from different types of waste after a running time of six years are presented and discussed.

  20. Evaluating leachate recirculation with cellulase addition to enhance waste biostabilisation and landfill gas production.

    PubMed

    Frank, R R; Davies, S; Wagland, S T; Villa, R; Trois, C; Coulon, F

    2016-09-01

    The effect of leachate recirculation with cellulase augmentation on municipal solid waste (MSW) biostabilisation and landfill gas production was investigated using batch bioreactors to determine the optimal conditions of moisture content, temperature and nutrients. Experimentation was thereafter scaled-up in 7L bioreactors. Three conditions were tested including (1) leachate recirculation only, (2) leachate recirculation with enzyme augmentation and (3) no leachate recirculation (control). Cumulative biogas production of the batch tests indicated that there was little difference between the leachate and control test conditions, producing on average 0.043m(3)biogaskg(-1) waste. However the addition of cellulase at 15×10(6)Utonne(-1) waste doubled the biogas production (0.074m(3)biogaskg(-1) waste). Similar trend was observed with the bioreactors. Cellulase addition also resulted in the highest COD reduction in both the waste and the leachate samples (47% and 42% COD reduction, respectively). In both cases, the quantity of biogas produced was closer to the lower value of theoretical and data-based biogas prediction indicators (0.05-0.4m(3)biogaskg(-1) waste). This was likely due to a high concentration of heavy metals present in the leachate, in particular Cr and Mn, which are known to be toxic to methanogens. The cost-benefit analysis (CBA) based on the settings of the study (cellulase concentration of 15×10(6)Utonne(-1) waste) showed that leachate bioaugmentation using cellulase is economically viable, with a net benefit of approximately €12.1million on a 5Mt mixed waste landfill. PMID:27397800

  1. Evaluating leachate recirculation with cellulase addition to enhance waste biostabilisation and landfill gas production.

    PubMed

    Frank, R R; Davies, S; Wagland, S T; Villa, R; Trois, C; Coulon, F

    2016-09-01

    The effect of leachate recirculation with cellulase augmentation on municipal solid waste (MSW) biostabilisation and landfill gas production was investigated using batch bioreactors to determine the optimal conditions of moisture content, temperature and nutrients. Experimentation was thereafter scaled-up in 7L bioreactors. Three conditions were tested including (1) leachate recirculation only, (2) leachate recirculation with enzyme augmentation and (3) no leachate recirculation (control). Cumulative biogas production of the batch tests indicated that there was little difference between the leachate and control test conditions, producing on average 0.043m(3)biogaskg(-1) waste. However the addition of cellulase at 15×10(6)Utonne(-1) waste doubled the biogas production (0.074m(3)biogaskg(-1) waste). Similar trend was observed with the bioreactors. Cellulase addition also resulted in the highest COD reduction in both the waste and the leachate samples (47% and 42% COD reduction, respectively). In both cases, the quantity of biogas produced was closer to the lower value of theoretical and data-based biogas prediction indicators (0.05-0.4m(3)biogaskg(-1) waste). This was likely due to a high concentration of heavy metals present in the leachate, in particular Cr and Mn, which are known to be toxic to methanogens. The cost-benefit analysis (CBA) based on the settings of the study (cellulase concentration of 15×10(6)Utonne(-1) waste) showed that leachate bioaugmentation using cellulase is economically viable, with a net benefit of approximately €12.1million on a 5Mt mixed waste landfill.

  2. Consolidated, multimedia environmental review and licensing of a landfill gas combustion/electrical generation system in Maryland

    SciTech Connect

    Goldstein, D.R.; Brown, D.H.; Ross, J.B.; Mountain, P.D.

    1999-07-01

    To build a power plant or transmission line in the State of Maryland, a company must obtain a Certificate of Public Convenience and Necessity (CPCN) from the Maryland Public Service Commission (PSC). As part of this licensing process, applicants must address a full range of environmental, engineering, socioeconomic, planning, need, and cost issues. The CPCN constitutes permission to construct and operate the facility, and includes issuance of the required air quality and water appropriations permits. The Maryland Power Plant Research Program (PPRP) serves as the lead agency for the consolidated review of CPCN projects. A recent project in Maryland involved the beneficial use of collected landfill gas from a closed municipal solid waste landfill for the generation of up to 4 Megawatts (MW) of electricity. This electrical generation will be continuously fed into the existing transmission system under a power purchase agreement with the local power company. The project is unique is several aspects: the use of former Rolls Royce aircraft engines fitted with generator sets to produce electricity; the beneficial reuse of landfill gas which is currently being flared at the landfill; and the collaborative environmental review that was conducted for this project that resulted in a streamlined licensing approach. This paper will include: a description of the landfill gas combustion/electrical generation system; an explanation of the review process conducted for the project including New Source Review, ambient air impacts assessed through air dispersion modeling, noise generation impacts, and ecological impacts; background on power plant licensing in Maryland; and a discussion of how the collaborative approach led by PPRP proved to be proactive and environmentally beneficial.

  3. The effectiveness of composite lining systems in controlling the leakage of leachate from sanitary landfills to groundwater.

    PubMed

    Gan, T Y; Friesen, G

    1991-10-01

    Leachate, the hazardous liquid that percolated through the refuse layers of a sanitary landfill, if it leaks through the landfill lining system, can become a serious source of groundwater pollution. In the past, leaks have been detected in many landfills lined with flexible membrane liners (FML) whose failure may be attributed to flaws such as imperfect seaming, rips, and tears of the membrane, or from chemical attack that dissolves the membrane. Recent studies have shown that composite lining systems which include either a clayey subbase or a layer of geotextile in addition to the FML, can substantially reduce the leakage of leachate. Therefore in this study, four different lining systems are proposed and evaluated to determine their effectiveness in controlling leachate flow under various degree of flaws (referred to as leakage fraction LF) in the FML. The Hydrologic Evaluation of Landfill Performance (HELP) computer model of the Environmental Protection Agency of USA, currently the most widely accepted model for predicting the performance of leachate collection systems in that country, is used to evaluate the following lining systems: (1) a single FML or liner, (2) a single FML with a clayey composite, (3) a single FML with a geotextile called Claymax, and (4) a double FML. Based on the climatic conditions and the present lining construction cost of Alaska, the study shows that a single FML or liner is the most economical but it is also the least effective in controlling leachate flow. Design (3), a single FML with a geotextile, costs about 50 percent more but it reduces the leakage of leachate by several orders. Design (2) is also effective but the cost incurred in constructing a 3 feet thick clayey subbase is prohibitive and thus to effectively and economically minimize the hazards of potential groundwater contamination by leachate, Design (3) is recommended as the composite lining system for future landfill sites.

  4. Enhanced Carbon Dioxide Capture from Landfill Gas Using Bifunctionalized Benzimidazole-Linked Polymers.

    PubMed

    Islamoglu, Timur; Behera, Swayamprabha; Kahveci, Zafer; Tessema, Tsemre-Dingel; Jena, Puru; El-Kaderi, Hani M

    2016-06-15

    Tuning the binding affinity of small gases and their selective uptake by porous adsorbents are vital for effective CO2 removal from gas mixtures for environmental protection and fuel upgrading. In this study, an amine-functionalized benzimidazole-linked polymer (BILP-6-NH2) was synthesized by a combination of pre- and postsynthetic modification techniques in two steps. Presynthetic incorporation of nitro groups resulted in stoichiometric functionalization (1 nitro/phenyl) in addition to noninvasive functionalization, where more than 80% of the surface area maintained compared to BILP-6. Experimental studies presented enhanced CO2 uptake and CO2/CH4 selectivity in BILP-6-NH2 compared to BILP-6, which are governed by the synergetic effect of benzimidazole and amine moieties. DFT calculations were used to understand the interaction modes of CO2 with BILP-6-NH2 and confirmed the efficacy of amine groups. Encouraged by the enhanced uptake and selectivity in BILP-6-NH2, we have evaluated its performance in landfill gas separation under vacuum swing adsorption (VSA) settings, which resulted in very promising working capacity and sorbent selection parameters outperforming most of the best solid adsorbent in the literature. PMID:27228220

  5. Effect of season, substrate composition, and plant growth on landfill leachate treatment in a constructed wetland

    SciTech Connect

    Surface, J.M. ); Peverly, J.H. . Dept. of Soil, Crops, and Atmospheric Sciences); Steenhuis, T.S. . Dept. of Agricultural and Biological Engineering); Sanford, W.E. )

    1991-01-01

    In 1989 the US, Geological Survey (USGS), in cooperation with Tompkins County, New York Departments of Planning and Solid Waste, began a 3-year study at a municipal solid-waste landfill near Ithaca, N.Y., to test the efficiency of leachate treatment by constructed wetlands and to examine the associated treatment processes. Specific objectives of the study were to examine: (1) Treatment efficiency as function of substrate composition and grain size, degree of plant growth, and seasonal changes in evapotranspiration rates and microbial activity; (2) effects of leachate and plant growth on the hydraulic characteristics of the substrate; and (3) chemical, biological, and physical processes by which nutrients, metals, and organic compounds are removed from leachate as it flows through the substrate. This report addresses the first two of these objectives and briefly discusses the third. It (1) describes the substrate plots, leachate-distribution system, sampling methods, and analytical procedures; and (2) presents results in terms of (a) percent removal rates of selected constituents between inflow- and outflow-sampling points, (b) seasonal effects on constituent-removal rates, and (c) effect of substrate composition on constituent removal and plant growth.

  6. Effect of season, substrate composition, and plant growth on landfill leachate treatment in a constructed wetland

    SciTech Connect

    Surface, J.M.; Peverly, J.H.; Steenhuis, T.S.; Sanford, W.E.

    1991-12-31

    In 1989 the US, Geological Survey (USGS), in cooperation with Tompkins County, New York Departments of Planning and Solid Waste, began a 3-year study at a municipal solid-waste landfill near Ithaca, N.Y., to test the efficiency of leachate treatment by constructed wetlands and to examine the associated treatment processes. Specific objectives of the study were to examine: (1) Treatment efficiency as function of substrate composition and grain size, degree of plant growth, and seasonal changes in evapotranspiration rates and microbial activity; (2) effects of leachate and plant growth on the hydraulic characteristics of the substrate; and (3) chemical, biological, and physical processes by which nutrients, metals, and organic compounds are removed from leachate as it flows through the substrate. This report addresses the first two of these objectives and briefly discusses the third. It (1) describes the substrate plots, leachate-distribution system, sampling methods, and analytical procedures; and (2) presents results in terms of (a) percent removal rates of selected constituents between inflow- and outflow-sampling points, (b) seasonal effects on constituent-removal rates, and (c) effect of substrate composition on constituent removal and plant growth.

  7. Landfill Gas Conversion to LNG and LCO{sub 2}. Phase II Final Report for January 25, 1999 - April 30, 2000

    SciTech Connect

    Brown, W. R.; Cook, W. J.; Siwajek, L. A.

    2000-10-20

    This report summarizes work on the development of a process to produce LNG (liquefied methane) for heavy vehicle use from landfill gas (LFG) using Acrion's CO{sub 2} wash process for contaminant removal and CO{sub 2} recovery.

  8. Integrated Combined Heat and Power/Advanced Reciprocating Internal Combustion Engine System for Landfill Gas to Power Applications

    SciTech Connect

    2009-02-01

    Gas Technology Institute will collaborate with Integrated CHP Systems Corporation, West Virginia University, Vronay Engineering Services, KAR Engineering Associates, Pioneer Air Systems, and Energy Concepts Company to recover waste heat from reciprocating engines. The project will integrate waste heat recovery along with gas clean-up technology system improvements. This will address fuel quality issues that have hampered expanded use of opportunity fuels such as landfill gas, digester biogas, and coal mine methane. This will enable increased application of CHP using renewable and domestically derived opportunity fuels.

  9. Steady-state analytical models for performance assessment of landfill composite liners.

    PubMed

    Xie, Haijian; Jiang, Yuansheng; Zhang, Chunhua; Feng, Shijin; Qiu, Zhanhong

    2015-08-01

    One-dimensional mathematical models were developed for organic contaminant transport through landfill composite liners consisting of a geomembrane (GM) and a geosynthetic clay liner (GCL) or a GM and a compacted clay liner (CCL). The combined effect of leakage through GM defects, diffusion in GM and the underlying soil liners, and degradation in soil liners were considered. Steady state analytical solutions were provided for the proposed mathematical models, which consider the different combinations of advection, diffusion, and degradation. The analytical solutions of the time lag for contaminant transport in the composite liners were also derived. The performance of GM/GCL and GM/CCL was analyzed. For GM/GCL, the bottom flux can be reduced by a factor of 4 when the leachate head decreases from 10 to 0.3 m. The influence of degradation can be ignored for GM/GCL. For GM/CCL, when the leachate head decreases from 10 to 0.3 m, the bottom flux decreases by a factor of 2-4. Leachate head has greater influence on bottom flux in case of larger degradation rate (e.g., half-life = 1 year) compared to the case with lower degradation rate (e.g., half-life = 10 years). As contaminant half-life in soil liner decreases from 10 to 1 year, bottom flux decreases by approximately 2.7 magnitudes of orders. It is indicated that degradation may have greater influence on time lag of composite liner than leachate head. As leachate head increases from zero to 10 m, time lag for GM/CCL can be reduced by 5-6 years. Time lag for the same composite liner can be reduced by 10-11 years as contaminant half-life decreases from 10 to 1 year. Reducing leachate head acting on composite liners and increasing the degradation capacity of the soil liner would be the effective methods to improve the performance of the composite liners. The proposed analytical solutions are relatively simple and can be used for preliminary design and performance assessment of composite liners. PMID:25893615

  10. Case study on prediction of remaining methane potential of landfilled municipal solid waste by statistical analysis of waste composition data.

    PubMed

    Sel, İlker; Çakmakcı, Mehmet; Özkaya, Bestamin; Suphi Altan, H

    2016-10-01

    Main objective of this study was to develop a statistical model for easier and faster Biochemical Methane Potential (BMP) prediction of landfilled municipal solid waste by analyzing waste composition of excavated samples from 12 sampling points and three waste depths representing different landfilling ages of closed and active sections of a sanitary landfill site located in İstanbul, Turkey. Results of Principal Component Analysis (PCA) were used as a decision support tool to evaluation and describe the waste composition variables. Four principal component were extracted describing 76% of data set variance. The most effective components were determined as PCB, PO, T, D, W, FM, moisture and BMP for the data set. Multiple Linear Regression (MLR) models were built by original compositional data and transformed data to determine differences. It was observed that even residual plots were better for transformed data the R(2) and Adjusted R(2) values were not improved significantly. The best preliminary BMP prediction models consisted of D, W, T and FM waste fractions for both versions of regressions. Adjusted R(2) values of the raw and transformed models were determined as 0.69 and 0.57, respectively. PMID:27444845

  11. Case study on prediction of remaining methane potential of landfilled municipal solid waste by statistical analysis of waste composition data.

    PubMed

    Sel, İlker; Çakmakcı, Mehmet; Özkaya, Bestamin; Suphi Altan, H

    2016-10-01

    Main objective of this study was to develop a statistical model for easier and faster Biochemical Methane Potential (BMP) prediction of landfilled municipal solid waste by analyzing waste composition of excavated samples from 12 sampling points and three waste depths representing different landfilling ages of closed and active sections of a sanitary landfill site located in İstanbul, Turkey. Results of Principal Component Analysis (PCA) were used as a decision support tool to evaluation and describe the waste composition variables. Four principal component were extracted describing 76% of data set variance. The most effective components were determined as PCB, PO, T, D, W, FM, moisture and BMP for the data set. Multiple Linear Regression (MLR) models were built by original compositional data and transformed data to determine differences. It was observed that even residual plots were better for transformed data the R(2) and Adjusted R(2) values were not improved significantly. The best preliminary BMP prediction models consisted of D, W, T and FM waste fractions for both versions of regressions. Adjusted R(2) values of the raw and transformed models were determined as 0.69 and 0.57, respectively.

  12. Cryogenic Heat-Exchanger Design for Freeze-out Removal of Carbon Dioxide from Landfill Gas

    NASA Astrophysics Data System (ADS)

    Chang, Ho-Myung; Chung, Myung Jin; Park, Seong Bum

    A cryogenic heat exchanger to remove carbon dioxide from landfill gas (LFG) is proposed and designed for applications to LNG production in distributed-scale. Since the major components of LFG are methane and carbon dioxide, CO2 removal is a significant pre-process in the liquefaction systems. A new and simple approach is proposed to directly remove carbon dioxide as frost on the surface wall along the cooling passage in a liquefying heat exchanger and to install two identical heat exchangers in parallel for alternative switching. As a first step of feasibility study, combined heat and mass transfer analysis is performed on the freeze-out process of CO2 in a counterflow heat exchanger, where CH4-CO2 mixture is cooled below its frost temperature in thermal contact with cold refrigerant. Engineering correlations for the analogy of heat and mass transfer are incorporated into numerical heat exchanger analysis with detailed fluid properties. The developed analytical model is used to estimate the distribution of CO2 accumulation and the required heat exchanger size with latent thermal load for the cryogenic CO2 removal in various operating conditions.

  13. Composition for absorbing hydrogen from gas mixtures

    DOEpatents

    Heung, Leung K.; Wicks, George G.; Lee, Myung W.

    1999-01-01

    A hydrogen storage composition is provided which defines a physical sol-gel matrix having an average pore size of less than 3.5 angstroms which effectively excludes gaseous metal hydride poisons while permitting hydrogen gas to enter. The composition is useful for separating hydrogen gas from diverse gas streams which may have contaminants that would otherwise render the hydrogen absorbing material inactive.

  14. A fully coupled model for water-gas-heat reactive transport with methane oxidation in landfill covers.

    PubMed

    Ng, C W W; Feng, S; Liu, H W

    2015-03-01

    Methane oxidation in landfill covers is a complex process involving water, gas and heat transfer as well as microbial oxidation. The coupled phenomena of microbial oxidation, water, gas, and heat transfer are not fully understood. In this study, a new model is developed that incorporates water-gas-heat coupled reactive transport in unsaturated soil with methane oxidation. Effects of microbial oxidation-generated water and heat are included. The model is calibrated using published data from a laboratory soil column test. Moreover, a series of parametric studies are carried out to investigate the influence of microbial oxidation-generated water and heat, initial water content on methane oxidation efficiency. Computed and measured results of gas concentration and methane oxidation rate are consistent. It is found that the coupling effects between water-gas-heat transfer and methane oxidation are significant. Ignoring microbial oxidation-generated water and heat can result in a significant difference in methane oxidation efficiency by 100%.

  15. A fully coupled model for water-gas-heat reactive transport with methane oxidation in landfill covers.

    PubMed

    Ng, C W W; Feng, S; Liu, H W

    2015-03-01

    Methane oxidation in landfill covers is a complex process involving water, gas and heat transfer as well as microbial oxidation. The coupled phenomena of microbial oxidation, water, gas, and heat transfer are not fully understood. In this study, a new model is developed that incorporates water-gas-heat coupled reactive transport in unsaturated soil with methane oxidation. Effects of microbial oxidation-generated water and heat are included. The model is calibrated using published data from a laboratory soil column test. Moreover, a series of parametric studies are carried out to investigate the influence of microbial oxidation-generated water and heat, initial water content on methane oxidation efficiency. Computed and measured results of gas concentration and methane oxidation rate are consistent. It is found that the coupling effects between water-gas-heat transfer and methane oxidation are significant. Ignoring microbial oxidation-generated water and heat can result in a significant difference in methane oxidation efficiency by 100%. PMID:25489976

  16. Research, development and demonstration in the design of sanitary landfill to optimize the generation and capture of compressible gas

    NASA Astrophysics Data System (ADS)

    Nosanov, M. E.; Teeple, F. E.; Buesch, S. C.

    1982-02-01

    The influences of selected factors on the generation and recovery of methane gas from sanitary landfills were investigated. The factors included encapsulation, shredding, air classifying, moisture, and pH. Facilities consisting of six model sanitary landfill cells, each with a capacity of approximately 450 cubic yards of municipal waste, and auxiliary subsystems were constructed. Municipal waste in each cell is contained in a 30-mil thick polyvinly chloride plastic sheeting forming a virtually gas-tight envelope. Two cells were filled with as-collected urban waste, two with shredded waste, and two with shredded and air classified waste, constituting three pairs of cells. One of each pair is a control cell with the other used as an experimental variable. Systems were provided for adding measured amounts of water, removing and recirculating leachate, and for extracting gas and measuring gas flow. During testing, gas production and internal cell characteristics were measured to determine the effects of mechanical processing, moisture content, and leachate pH.

  17. Metal-modified and vertically aligned carbon nanotube sensors array for landfill gas monitoring applications.

    PubMed

    Penza, M; Rossi, R; Alvisi, M; Serra, E

    2010-03-12

    Vertically aligned carbon nanotube (CNT) layers were synthesized on Fe-coated low-cost alumina substrates using radio-frequency plasma enhanced chemical vapour deposition (RF-PECVD) technology. A miniaturized CNT-based gas sensor array was developed for monitoring landfill gas (LFG) at a temperature of 150 degrees C. The sensor array was composed of 4 sensing elements with unmodified CNT, and CNT loaded with 5 nm nominally thick sputtered nanoclusters of platinum (Pt), ruthenium (Ru) and silver (Ag). Chemical analysis of multicomponent gas mixtures constituted of CO(2), CH(4), H(2), NH(3), CO and NO(2) has been performed by the array sensor responses and pattern recognition based on principal component analysis (PCA). The PCA results demonstrate that the metal-decorated and vertically aligned CNT sensor array is able to discriminate the NO(2) presence in the multicomponent mixture LFG. The NO(2) gas detection in the mixture LFG was proved to be very sensitive, e.g.: the CNT:Ru sensor shows a relative change in the resistance of 1.50% and 0.55% for NO(2) concentrations of 3.3 ppm and 330 ppb dispersed in the LFG, respectively, with a wide NO(2) gas concentration range measured from 0.33 to 3.3 ppm, at the sensor temperature of 150 degrees C. The morphology and structure of the CNT networks have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. A forest-like nanostructure of vertically aligned CNT bundles in the multi-walled form appeared with a height of about 10 microm and a single-tube diameter varying in the range of 5-35 nm. The intensity ratio of the Raman spectroscopy D-peak and G-peak indicates the presence of disorder and defects in the CNT networks. The size of the metal (Pt, Ru, Ag) nanoclusters decorating the CNT top surface varies in the range of 5-50 nm. Functional characterization based on electrical charge transfer sensing mechanisms in the metal-modified CNT-chemoresistor array

  18. Energy potential of modern landfills

    SciTech Connect

    Bogner, J.E.

    1990-01-01

    Methane produced by refuse decomposition in a sanitary landfill can be recovered for commercial use. Landfill methane is currently under-utilized, with commercial recovery at only a small percentage of US landfills. New federal regulations mandating control of landfill gas migration and atmospheric emissions are providing impetus to methane recovery schemes as a means of recovering costs for increased environmental control. The benefits of landfill methane recovery include utilization of an inexpensive renewable energy resource, removal of explosive gas mixtures from the subsurface, and mitigation of observed historic increases in atmospheric methane. Increased commercial interest in landfill methane recovery is dependent on the final form of Clean Air Act amendments pertaining to gaseous emissions from landfills; market shifts in natural gas prices; financial incentives for development of renewable energy resources; and support for applied research and development to develop techniques for increased control of the gas generation process in situ. This paper will discuss the controls on methane generation in landfills. In addition, it will address how landfill regulations affect landfill design and site management practices which, in turn, influence decomposition rates. Finally, future trends in landfilling, and their relationship to gas production, will be examined. 19 refs., 2 figs., 3 tabs.

  19. Greenhouse gas accounting of the proposed landfill extension and advanced incineration facility for municipal solid waste management in Hong Kong.

    PubMed

    Woon, K S; Lo, Irene M C

    2013-08-01

    The burgeoning of municipal solid waste (MSW) disposal issue and climate change have drawn massive attention from people. On the one hand, Hong Kong is facing a controversial debate over the implementation of proposed landfill extension (LFE) and advanced incineration facility (AIF) to curb the MSW disposal issue. On the other hand, the Hong Kong Special Administrative Region Government is taking concerted efforts to reduce the carbon intensity in this region. This paper discusses the greenhouse gas (GHG) emissions from four proposed waste disposal scenarios, covering the proposed LFE and AIF within a defined system boundary. On the basis of the data collected, assumptions made, and system boundary defined in this study, the results indicate that AIF releases less GHG emissions than LFE. The GHG emissions from LFE are highly contributed by the landfill methane (CH4) emissions but offset by biogenic carbon storage, while the GHG emissions from AIF are mostly due to the stack discharge system but offset by the energy recovery system. Furthermore, parametric sensitivity analyses show that GHG emissions are strongly dependent on the landfill CH4 recovery rate, types of electricity displaced by energy recovery systems, and the heating value of MSW, altering the order of preferred waste disposal scenarios. This evaluation provides valuable insights into the applicability of a policy framework for MSW management practices in reducing GHG emissions. PMID:23697849

  20. Greenhouse gas accounting of the proposed landfill extension and advanced incineration facility for municipal solid waste management in Hong Kong.

    PubMed

    Woon, K S; Lo, Irene M C

    2013-08-01

    The burgeoning of municipal solid waste (MSW) disposal issue and climate change have drawn massive attention from people. On the one hand, Hong Kong is facing a controversial debate over the implementation of proposed landfill extension (LFE) and advanced incineration facility (AIF) to curb the MSW disposal issue. On the other hand, the Hong Kong Special Administrative Region Government is taking concerted efforts to reduce the carbon intensity in this region. This paper discusses the greenhouse gas (GHG) emissions from four proposed waste disposal scenarios, covering the proposed LFE and AIF within a defined system boundary. On the basis of the data collected, assumptions made, and system boundary defined in this study, the results indicate that AIF releases less GHG emissions than LFE. The GHG emissions from LFE are highly contributed by the landfill methane (CH4) emissions but offset by biogenic carbon storage, while the GHG emissions from AIF are mostly due to the stack discharge system but offset by the energy recovery system. Furthermore, parametric sensitivity analyses show that GHG emissions are strongly dependent on the landfill CH4 recovery rate, types of electricity displaced by energy recovery systems, and the heating value of MSW, altering the order of preferred waste disposal scenarios. This evaluation provides valuable insights into the applicability of a policy framework for MSW management practices in reducing GHG emissions.

  1. Gas composition shifts in Devonian shales

    SciTech Connect

    Schettler, P.D.; Parmely, C.R. )

    1989-08-01

    Analysis of the gas composition of Devonian shale wells indicates that the composition of produced gas shifts during the production history of the well. Possible mechanisms to explain this behavior are examined in light of field and laboratory data. Application of diffusion theory is made to explain adsorption-like behavior exhibited by some shales.

  2. Well-to-Wheels analysis of landfill gas-based pathways and their addition to the GREET model.

    SciTech Connect

    Mintz, M.; Han, J.; Wang, M.; Saricks, C.; Energy Systems

    2010-06-30

    Today, approximately 300 million standard cubic ft/day (mmscfd) of natural gas and 1600 MW of electricity are produced from the decomposition of organic waste at 519 U.S. landfills (EPA 2010a). Since landfill gas (LFG) is a renewable resource, this energy is considered renewable. When used as a vehicle fuel, compressed natural gas (CNG) produced from LFG consumes up to 185,000 Btu of fossil fuel and generates from 1.5 to 18.4 kg of carbon dioxide-equivalent (CO{sub 2}e) emissions per million Btu of fuel on a 'well-to-wheel' (WTW) basis. This compares with approximately 1.1 million Btu and 78.2 kg of CO{sub 2}e per million Btu for CNG from fossil natural gas and 1.2 million Btu and 97.5 kg of CO{sub 2}e per million Btu for petroleum gasoline. Because of the additional energy required for liquefaction, LFG-based liquefied natural gas (LNG) requires more fossil fuel (222,000-227,000 Btu/million Btu WTW) and generates more GHG emissions (approximately 22 kg CO{sub 2}e /MM Btu WTW) if grid electricity is used for the liquefaction process. However, if some of the LFG is used to generate electricity for gas cleanup and liquefaction (or compression, in the case of CNG), vehicle fuel produced from LFG can have no fossil fuel input and only minimal GHG emissions (1.5-7.7 kg CO{sub 2}e /MM Btu) on a WTW basis. Thus, LFG-based natural gas can be one of the lowest GHG-emitting fuels for light- or heavy-duty vehicles. This report discusses the size and scope of biomethane resources from landfills and the pathways by which those resources can be turned into and utilized as vehicle fuel. It includes characterizations of the LFG stream and the processes used to convert low-Btu LFG into high-Btu renewable natural gas (RNG); documents the conversion efficiencies and losses of those processes, the choice of processes modeled in GREET, and other assumptions used to construct GREET pathways; and presents GREET results by pathway stage. GREET estimates of well-to-pump (WTP), pump

  3. Geochemical and VOC-constraints on landfill gas age and attenuation characteristics: A case study from a waste disposal facility in Southern California.

    PubMed

    Hagedorn, Benjamin; Kerfoot, Henry B; Verwiel, Mark; Matlock, Bruce

    2016-07-01

    In this study, a multi-tracer approach was applied to a complex, methane-impacted site in Southern California to (1) distinguish between natural gas and landfill gas (LFG)-derived methane impacts at site perimeter gas probes, (2) estimate the relative age of the LFG at these probes, and (3) document natural attenuation trends during a 3-year monitoring period. Relationships between methane and ethane values suggest that at the majority of probes, methane is from LFG and not from natural gas and that the relative contribution of LFG methane at these probes has increased over the monitoring period. To evaluate whether LFG is attenuating in the subsurface, the relative age of LFG was estimated by comparing readily degraded VOCs that are major constituents in LFG (toluene in this case) with those resistant to degradation (Freons). Time-series data trends are consistent with several probes being impacted by fresh LFG from recent releases that occurred after the update of the local LFG collection and control system (LFGCCS). Data further indicate some probes to be only affected by legacy LFG from a past release that occurred prior to the LFGCCS update and that, because of a lack of oxygen in the subsurface, had not been fully degraded. The outlined attenuation evaluation methodology is potentially applicable to other sites or even groundwater contaminants; however, the assessment is limited by the degree of homogeneity of the LFG source composition and non-LFG-derived toluene inputs to the analyzed samples. PMID:26601889

  4. BIOREACTOR LANDFILL DESIGN

    EPA Science Inventory

    Modern landfill design entails many elements including foundations, liner systems, leachate collection systems, stormwater control systems, slope stability considerations, leachate management systems, gas extraction systems, and capping and closure. The use of bioreactor technolo...

  5. Leaky Landfills.

    ERIC Educational Resources Information Center

    Jones, Linda L. Cronin

    1992-01-01

    Provides background information on landfills and describes an activity where students learn how a modern landfill is constructed and develop an understanding of the reasons for several regulations regarding modern landfill construction. Students design and construct working models of three types of landfills. (PR)

  6. Prediction of Combustion Gas Deposit Compositions

    NASA Technical Reports Server (NTRS)

    Kohl, F. J.; Mcbride, B. J.; Zeleznik, F. J.; Gordon, S.

    1985-01-01

    Demonstrated procedure used to predict accurately chemical compositions of complicated deposit mixtures. NASA Lewis Research Center's Computer Program for Calculation of Complex Chemical Equilibrium Compositions (CEC) used in conjunction with Computer Program for Calculation of Ideal Gas Thermodynamic Data (PAC) and resulting Thermodynamic Data Base (THDATA) to predict deposit compositions from metal or mineral-seeded combustion processes.

  7. Ammoniacal nitrogen and COD removal from semi-aerobic landfill leachate using a composite adsorbent: fixed bed column adsorption performance.

    PubMed

    Halim, Azhar Abdul; Aziz, Hamidi Abdul; Johari, Megat Azmi Megat; Ariffin, Kamar Shah; Adlan, Mohd Nordin

    2010-03-15

    The performance of a carbon-mineral composite adsorbent used in a fixed bed column for the removal of ammoniacal nitrogen and aggregate organic pollutant (COD), which are commonly found in landfill leachate, was evaluated. The breakthrough capacities for ammoniacal nitrogen and COD adsorption were 4.46 and 3.23 mg/g, respectively. Additionally, the optimum empty bed contact time (EBCT) was 75 min. The column efficiency for ammoniacal nitrogen and COD adsorption using fresh adsorbent was 86.4% and 92.6%, respectively, and these values increased to 90.0% and 93.7%, respectively, after the regeneration process. PMID:19945216

  8. USING LANDFILL GAS IN FUEL CELLS - A STEP CLOSER TO COMMERICAL REALITY

    EPA Science Inventory

    The article discusses Phase II and Phase III results of a U.S. EPA program underway at International Fuel Cells Corporation. The program involves controlling methane emissions from landfills using a fuel cell. The fuel cell would reduce air emissions affecting global warming, aci...

  9. Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil.

    PubMed

    Wickramarachchi, Praneeth; Kawamoto, Ken; Hamamoto, Shoichiro; Nagamori, Masanao; Moldrup, Per; Komatsu, Toshiko

    2011-12-01

    Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, ρ(b), and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D(p)/D(o), ratio of gas diffusion coefficients in soil and free air) and air permeability (k(a)) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting ρ(b) values ranging from 1.40 to 2.10 g cm(-3). Results showed that D(p) and k(a) values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2mm) under variably-saturated conditions for a given soil-air content (ε), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D(p) and k(a) was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D(p)/D(f), the ratio of measured D(p) to D(p) in total porosity (f), (ii) for air permeability k(a)/k(a)(,pF4.1), the ratio of measured k(a) to k(a) at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content (ε) to total porosity (f) (air saturation). Based on the normalized parameters, predictive power-law models for D(p)(ε/f) and k(a)(ε/f) models were developed based on a single parameter (water blockage factor M for D(p) and P for k(a)). The water blockage factors, M and P, were found to be linearly correlated to ρ(b) values, and the effects of dry bulk density on D(p) and k(a) for both '+gravel' and '-gravel' fractions were well accounted for by the new models.

  10. Quantifying spatial and temporal variability of methane emissions from a complex area source: case study of a central Indiana landfill

    EPA Science Inventory

    strengths, limitations, and uncertainties of these two approaches. Because US landfills are highly-engineered and composed of daily, intermediate, and final cover areas with differing thicknesses, composition, and implementation of gas recovery, we also expected different emissi...

  11. 2D Time-lapse Resistivity Monitoring of an Organic Produced Gas Plume in a Landfill using ERT.

    NASA Astrophysics Data System (ADS)

    Amaral, N. D.; Mendonça, C. A.; Doherty, R.

    2014-12-01

    This project has the objective to study a landfill located on the margins of Tietê River, in São Paulo, Brazil, using the electroresistivity tomography method (ERT). Due to huge organic matter concentrations in the São Paulo Basin quaternary sediments, there is subsurface depth related biogas accumulation (CH4 and CO2), induced by anaerobic degradation of the organic matter. 2D resistivity sections were obtained from a test area since March 2012, a total of 7 databases, being the last one dated from October 2013. The studied line has the length of 56m, the electrode interval is of 2m. In addition, there are two boreholes along the line (one with 3 electrodes and the other one with 2) in order to improve data quality and precision. The boreholes also have a multi-level sampling system that indicates the fluid (gas or water) presence in relation to depth. With our results it was possible to map the gas plume position and its area of extension in the sections as it is a positive resistivity anomaly, with the gas level having approximately 5m depth. With the time-lapse analysis (Matlab script) between the obtained 2D resistivity sections from the site, it was possible to map how the biogas volume and position change in the landfill in relation to time. Our preliminary results show a preferential gas pathway through the subsurface studied area. A consistent relation between the gas depth and obtained microbiological data from archea and bacteria population was also observed.

  12. Gas Permeable Chemochromic Compositions for Hydrogen Sensing

    NASA Technical Reports Server (NTRS)

    Bokerman, Gary (Inventor); Mohajeri, Nahid (Inventor); Muradov, Nazim (Inventor); Tabatabaie-Raissi, Ali (Inventor)

    2013-01-01

    A (H2) sensor composition includes a gas permeable matrix material intermixed and encapsulating at least one chemochromic pigment. The chemochromic pigment produces a detectable change in color of the overall sensor composition in the presence of H2 gas. The matrix material provides high H2 permeability, which permits fast permeation of H2 gas. In one embodiment, the chemochromic pigment comprises PdO/TiO2. The sensor can be embodied as a two layer structure with the gas permeable matrix material intermixed with the chemochromic pigment in one layer and a second layer which provides a support or overcoat layer.

  13. Alachua county southwest landfill gas production as a function of time. Master's thesis

    SciTech Connect

    Manley, G.R.

    1992-05-01

    Refuse disposal is an issue that must be addressed by virtually every community in the country. In the last twenty years, the demand for disposal techniques that minimize impact on the environment has increased. In addition, there has been a heightened interest in energy recovery from wastes as a method to reduce both the cost of waste disposal and national dependence on foreign energy supplies. The most common method of solid waste disposal in the United States is the utilization of sanitary landfills. Landfilling remains an economically viable method of solid waste disposal. Alternative means of disposal have often proven to be less effective in terms of both cost and in meeting solid waste disposal demands.

  14. Hydrogen sulfide generation in simulated construction and demolition debris landfills: impact of waste composition.

    PubMed

    Yang, Kenton; Xu, Qiyong; Townsend, Timothy G; Chadik, Paul; Bitton, Gabriel; Booth, Matthew

    2006-08-01

    Hydrogen sulfide (H2S) generation in construction and demolition (C&D) debris landfills has been associated with the biodegradation of gypsum drywall. Laboratory research was conducted to observe H2S generation when drywall was codisposed with different C&D debris constituents. Two experiments were conducted using simulated landfill columns. Experiment 1 consisted of various combinations of drywall, wood, and concrete to determine the impact of different waste constituents and combinations on H2S generation. Experiment 2 was designed to examine the effect of concrete on H2S generation and migration. The results indicate that decaying drywall, even alone, leached enough sulfate ions and organic matter for sulfate-reducing bacteria (SRB) to generate large H2S concentrations as high as 63,000 ppmv. The codisposed wastes show some effect on H2S generation. At the end of experiment 1, the wood/drywall and drywall alone columns possessed H2S concentrations > 40,000 ppmv. Conversely, H2S concentrations were < 1 ppmv in those columns containing concrete. Concrete plays a role in decreasing H2S by increasing pH out of the range for SRB growth and by reacting with H2S. This study also showed that wood lowered H2S concentrations initially by decreasing leachate pH values. Based on the results, two possible control mechanisms to mitigate H2S generation in C&D debris landfills are suggested. PMID:16933645

  15. Wastewater disposal to landfill-sites: a synergistic solution for centralized management of olive mill wastewater and enhanced production of landfill gas.

    PubMed

    Diamantis, Vasileios; Erguder, Tuba H; Aivasidis, Alexandros; Verstraete, Willy; Voudrias, Evangelos

    2013-10-15

    The present paper focuses on a largely unexplored field of landfill-site valorization in combination with the construction and operation of a centralized olive mill wastewater (OMW) treatment facility. The latter consists of a wastewater storage lagoon, a compact anaerobic digester operated all year round and a landfill-based final disposal system. Key elements for process design, such as wastewater pre-treatment, application method and rate, and the potential effects on leachate quantity and quality, are discussed based on a comprehensive literature review. Furthermore, a case-study for eight (8) olive mill enterprises generating 8700 m(3) of wastewater per year, was conceptually designed in order to calculate the capital and operational costs of the facility (transportation, storage, treatment, final disposal). The proposed facility was found to be economically self-sufficient, as long as the transportation costs of the OMW were maintained at ≤4.0 €/m(3). Despite that EU Landfill Directive prohibits wastewater disposal to landfills, controlled application, based on appropriately designed pre-treatment system and specific loading rates, may provide improved landfill stabilization and a sustainable (environmentally and economically) solution for effluents generated by numerous small- and medium-size olive mill enterprises dispersed in the Mediterranean region.

  16. Method for designing gas tag compositions

    DOEpatents

    Gross, K.C.

    1995-04-11

    For use in the manufacture of gas tags such as employed in a nuclear reactor gas tagging failure detection system, a method for designing gas tagging compositions utilizes an analytical approach wherein the final composition of a first canister of tag gas as measured by a mass spectrometer is designated as node No. 1. Lattice locations of tag nodes in multi-dimensional space are then used in calculating the compositions of a node No. 2 and each subsequent node so as to maximize the distance of each node from any combination of tag components which might be indistinguishable from another tag composition in a reactor fuel assembly. Alternatively, the measured compositions of tag gas numbers 1 and 2 may be used to fix the locations of nodes 1 and 2, with the locations of nodes 3-N then calculated for optimum tag gas composition. A single sphere defining the lattice locations of the tag nodes may be used to define approximately 20 tag nodes, while concentric spheres can extend the number of tag nodes to several hundred. 5 figures.

  17. Evolved gas composition monitoring by repetitive injection gas chromatography.

    PubMed

    White, Robert L

    2015-11-20

    Performance characteristics and applications of a small volume gas chromatograph oven are described. Heating and cooling properties of the apparatus are evaluated and examples are given illustrating the advantages of greatly reducing the air bath volume surrounding fused silica columns. Fast heating and cooling of the oven permit it to be employed for repetitive injection analyses. By using fast gas chromatography separations to achieve short assay cycle times, the apparatus can be employed for on-line species-specific gas stream composition monitoring when volatile species concentrations vary on time scales of a few minutes or longer. This capability facilitates repeated sampling and fast gas chromatographic separations of volatile product mixtures produced during thermal analyses. Applications of repetitive injection gas chromatography-mass spectrometry evolved gas analyses to monitoring purge gas effluent streams containing volatile acid catalyzed polymer cracking products are described. The influence of thermal analysis and chromatographic experimental parameters on effluent sampling frequency are delineated.

  18. Barometric pressure and gas composition

    NASA Technical Reports Server (NTRS)

    Malkin, V. B.

    1975-01-01

    Many factors affecting artificial gas atmosphere, which is used to maintain life during space flight, are considered. The wide variability of barometric pressure in spacecraft, due in large measure to spacecraft design is discussed. Explosive decompression is described; this develops from instantaneous depressurization of the cabin. Decompression sickness is reviewed, including bubble growth and evolution of gas bubbles in organisms. Dysbarism, hypoxia, and hypercapnia are also discussed.

  19. Compositional analysis of excavated landfill samples and the determination of residual biogas potential of the organic fraction.

    PubMed

    García, J; Davies, S; Villa, R; Gomes, D M; Coulon, F; Wagland, S T

    2016-09-01

    The objectives of this study were to assess the biogas potential of landfilled materials and to further validate the suitability of the enzymatic hydrolysis test EHT as a valuable alternative to substitute the standardised test currently in use (BMP). Both tests were applied to a range of landfill waste samples. The waste composition and volatile solids content (VS) profile together with the BMP test results showed that the biogas potential of the waste samples was directly related to their VS content, as expected. The positive correlation between the VS and the BMP test (r=0.67) suggests that the first could be used as a primary indicator of biogas potential of waste samples. Nevertheless, it should be validated against the BMP test because, occasionally, the VS content does not equate to the biogas production. This was mainly due to the paper content of the samples which also correlates positively (r=0.77) with the BMP biogas production. The EHT results showed a higher correlation with the BMP test (r=0.91) than in previous studies which used a wider mixture of enzymes containing cellulase, hemicellulase and carbohydrase. This finding positions the EHT as a quick assessing method for the biodegradability of waste samples in future sample regimes. PMID:27290632

  20. Mobile Robots for Localizing Gas Emission Sources on Landfill Sites: Is Bio-Inspiration the Way to Go?

    PubMed Central

    Hernandez Bennetts, Victor; Lilienthal, Achim J.; Neumann, Patrick P.; Trincavelli, Marco

    2011-01-01

    Roboticists often take inspiration from animals for designing sensors, actuators, or algorithms that control the behavior of robots. Bio-inspiration is motivated with the uncanny ability of animals to solve complex tasks like recognizing and manipulating objects, walking on uneven terrains, or navigating to the source of an odor plume. In particular the task of tracking an odor plume up to its source has nearly exclusively been addressed using biologically inspired algorithms and robots have been developed, for example, to mimic the behavior of moths, dung beetles, or lobsters. In this paper we argue that biomimetic approaches to gas source localization are of limited use, primarily because animals differ fundamentally in their sensing and actuation capabilities from state-of-the-art gas-sensitive mobile robots. To support our claim, we compare actuation and chemical sensing available to mobile robots to the corresponding capabilities of moths. We further characterize airflow and chemosensor measurements obtained with three different robot platforms (two wheeled robots and one flying micro-drone) in four prototypical environments and show that the assumption of a constant and unidirectional airflow, which is the basis of many gas source localization approaches, is usually far from being valid. This analysis should help to identify how underlying principles, which govern the gas source tracking behavior of animals, can be usefully “translated” into gas source localization approaches that fully take into account the capabilities of mobile robots. We also describe the requirements for a reference application, monitoring of gas emissions at landfill sites with mobile robots, and discuss an engineered gas source localization approach based on statistics as an alternative to biologically inspired algorithms. PMID:22319493

  1. Mobile robots for localizing gas emission sources on landfill sites: is bio-inspiration the way to go?

    PubMed

    Hernandez Bennetts, Victor; Lilienthal, Achim J; Neumann, Patrick P; Trincavelli, Marco

    2011-01-01

    Roboticists often take inspiration from animals for designing sensors, actuators, or algorithms that control the behavior of robots. Bio-inspiration is motivated with the uncanny ability of animals to solve complex tasks like recognizing and manipulating objects, walking on uneven terrains, or navigating to the source of an odor plume. In particular the task of tracking an odor plume up to its source has nearly exclusively been addressed using biologically inspired algorithms and robots have been developed, for example, to mimic the behavior of moths, dung beetles, or lobsters. In this paper we argue that biomimetic approaches to gas source localization are of limited use, primarily because animals differ fundamentally in their sensing and actuation capabilities from state-of-the-art gas-sensitive mobile robots. To support our claim, we compare actuation and chemical sensing available to mobile robots to the corresponding capabilities of moths. We further characterize airflow and chemosensor measurements obtained with three different robot platforms (two wheeled robots and one flying micro-drone) in four prototypical environments and show that the assumption of a constant and unidirectional airflow, which is the basis of many gas source localization approaches, is usually far from being valid. This analysis should help to identify how underlying principles, which govern the gas source tracking behavior of animals, can be usefully "translated" into gas source localization approaches that fully take into account the capabilities of mobile robots. We also describe the requirements for a reference application, monitoring of gas emissions at landfill sites with mobile robots, and discuss an engineered gas source localization approach based on statistics as an alternative to biologically inspired algorithms.

  2. Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil

    SciTech Connect

    Wickramarachchi, Praneeth; Kawamoto, Ken; Hamamoto, Shoichiro; Nagamori, Masanao; Moldrup, Per; Komatsu, Toshiko

    2011-12-15

    Highlights: > The effects of soil physical properties on gas transport parameters were investigated. > Higher values of D{sub p} and k{sub a} exhibited in the '+gravel' than the '-gravel' fraction at same soil-air content ({epsilon}). > Recent power law models for D{sub p} (WLR) and k{sub a} (RPL) were modified. > Model parameters were linearly related to easily measurable dry bulk density ({rho}{sub b}). - Abstract: Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, {rho}{sub b}, and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D{sub p}/D{sub o}, ratio of gas diffusion coefficients in soil and free air) and air permeability (k{sub a}) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting {rho}{sub b} values ranging from 1.40 to 2.10 g cm{sup -3}. Results showed that D{sub p} and k{sub a} values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2 mm) under variably-saturated conditions for a given soil-air content ({epsilon}), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D{sub p} and k{sub a} was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D{sub p}/D{sub f}, the ratio of measured D{sub p} to D{sub p} in total porosity (f), (ii) for air permeability k{sub a}/k{sub a,pF4.1}, the ratio of measured k{sub a} to k{sub a} at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content ({epsilon}) to total porosity (f) (air

  3. Measuring Water in Bioreactor Landfills

    NASA Astrophysics Data System (ADS)

    Han, B.; Gallagher, V. N.; Imhoff, P. T.; Yazdani, R.; Chiu, P.

    2004-12-01

    Methane is an important greenhouse gas, and landfills are the largest anthropogenic source in many developed countries. Bioreactor landfills have been proposed as one means of abating greenhouse gas emissions from landfills. Here, the decomposition of organic wastes is enhanced by the controlled addition of water or leachate to maintain optimal conditions for waste decomposition. Greenhouse gas abatement is accomplished by sequestration of photosynthetically derived carbon in wastes, CO2 offsets from energy use of waste derived gas, and mitigation of methane emission from the wastes. Maintaining optimal moisture conditions for waste degradation is perhaps the most important operational parameter in bioreactor landfills. To determine how much water is needed and where to add it, methods are required to measure water within solid waste. However, there is no reliable method that can measure moisture content simply and accurately in the heterogeneous environment typical of landfills. While well drilling and analysis of solid waste samples is sometimes used to determine moisture content, this is an expensive, time-consuming, and destructive procedure. To overcome these problems, a new technology recently developed by hydrologists for measuring water in the vadose zone --- the partitioning tracer test (PTT) --- was evaluated for measuring water in solid waste in a full-scale bioreactor landfill in Yolo County, CA. Two field tests were conducted in different regions of an aerobic bioreactor landfill, with each test measuring water in ≈ 250 ft3 of solid waste. Tracers were injected through existing tubes inserted in the landfill, and tracer breakthrough curves were measured through time from the landfill's gas collection system. Gas samples were analyzed on site using a field-portable gas chromatograph and shipped offsite for more accurate laboratory analysis. In the center of the landfill, PTT measurements indicated that the fraction of the pore space filled with water

  4. An analytical model for contaminant transport in landfill composite liners considering coupled effect of consolidation, diffusion, and degradation.

    PubMed

    Xie, Haijian; Yan, Huaxiang; Feng, Shijin; Wang, Qiao; Chen, Peixiong

    2016-10-01

    One-dimensional mathematical model is developed to investigate the behavior of contaminant transport in landfill composite liner system considering coupled effect of consolidation, diffusion, and degradation. The first- and second-type bottom boundary conditions are used to derive the steady-state and quasi-steady-state analytical solutions. The concentration profiles obtained by the proposed analytical solution are in good agreement with those obtained by the laboratory tests. The bottom concentration and flux of the soil liners can be greatly reduced when the degradation effect and porosity changing are considered. For the case under steady-state, the bottom flux and concentration for the case with t 1/2 =10 years can be 2.8 and 5.5 times lower than those of the case with t 1/2 =100 years, respectively. The bottom concentration and flux of the soil liners can be greatly reduced when the coefficient of volume compressibility decreases. For quasi-steady-state and with t 1/2 = 10 years, the bottom flux and concentration for the case with m v  = 0.02/MPa can be 17.4 and 21 times lower than the case with m v  = 0.5/MPa. This may be due to the fact that the true fluid velocity induced by consolidation is greater for the case with high coefficient of volume compressibility. The bottom flux for the case with single compacted clay liner (CCL) can be 1.5 times larger than that for the case with GMB/CCL considering diffusion and consolidation for DCM. The proposed analytical model can be used for verification of more complicated numerical models and assessment of the coupled effect of diffusion, consolidation, and degradation on contaminant transport in landfill liner systems. PMID:27370538

  5. An analytical model for contaminant transport in landfill composite liners considering coupled effect of consolidation, diffusion, and degradation.

    PubMed

    Xie, Haijian; Yan, Huaxiang; Feng, Shijin; Wang, Qiao; Chen, Peixiong

    2016-10-01

    One-dimensional mathematical model is developed to investigate the behavior of contaminant transport in landfill composite liner system considering coupled effect of consolidation, diffusion, and degradation. The first- and second-type bottom boundary conditions are used to derive the steady-state and quasi-steady-state analytical solutions. The concentration profiles obtained by the proposed analytical solution are in good agreement with those obtained by the laboratory tests. The bottom concentration and flux of the soil liners can be greatly reduced when the degradation effect and porosity changing are considered. For the case under steady-state, the bottom flux and concentration for the case with t 1/2 =10 years can be 2.8 and 5.5 times lower than those of the case with t 1/2 =100 years, respectively. The bottom concentration and flux of the soil liners can be greatly reduced when the coefficient of volume compressibility decreases. For quasi-steady-state and with t 1/2 = 10 years, the bottom flux and concentration for the case with m v  = 0.02/MPa can be 17.4 and 21 times lower than the case with m v  = 0.5/MPa. This may be due to the fact that the true fluid velocity induced by consolidation is greater for the case with high coefficient of volume compressibility. The bottom flux for the case with single compacted clay liner (CCL) can be 1.5 times larger than that for the case with GMB/CCL considering diffusion and consolidation for DCM. The proposed analytical model can be used for verification of more complicated numerical models and assessment of the coupled effect of diffusion, consolidation, and degradation on contaminant transport in landfill liner systems.

  6. LANDFILL BIOREACTOR PERFORMANCE, SECOND INTERIM REPORT

    EPA Science Inventory

    A bioreactor landfill is a landfill that is operated in a manner that is expected to increase the rate and extent of waste decomposition, gas generation, and settlement compared to a traditional landfill. This Second Interim Report was prepared to provide an interpretation of fie...

  7. METHANE PHYTOREMEDIATION BY VEGETATIVE LANDFILL COVER SYSTEMS

    EPA Science Inventory

    Landfill gas, consisting of methane and other gases, is produced from organic compounds degrading in landfills, contributes to global climate change, is toxic to various types of vegetation, and may pose a combustion hazard at higher concentrations. New landfills are required to ...

  8. Experimental and life cycle assessment analysis of gas emission from mechanically–biologically pretreated waste in a landfill with energy recovery

    SciTech Connect

    Di Maria, Francesco Sordi, Alessio; Micale, Caterina

    2013-11-15

    Highlights: • Bio-methane landfill emissions from different period (0, 4, 8, 16 weeks) MTB waste have been evaluated. • Electrical energy recoverable from landfill gas ranges from 11 to about 90 kW h/tonne. • Correlation between oxygen uptake, energy recovery and anaerobic gas production shows R{sup 2} ranging from 0.78 to 0.98. • LCA demonstrate that global impact related to gaseous emissions achieve minimum for 4 week of MBT. - Abstract: The global gaseous emissions produced by landfilling the Mechanically Sorted Organic Fraction (MSOF) with different weeks of Mechanical Biological Treatment (MBT) was evaluated for an existing waste management system. One MBT facility and a landfill with internal combustion engines fuelled by the landfill gas for electrical energy production operate in the waste management system considered. An experimental apparatus was used to simulate 0, 4, 8 and 16 weeks of aerobic stabilization and the consequent biogas potential (Nl/kg) of a large sample of MSOF withdrawn from the full-scale MBT. Stabilization achieved by the waste was evaluated by dynamic oxygen uptake and fermentation tests. Good correlation coefficients (R{sup 2}), ranging from 0.7668 to 0.9772, were found between oxygen uptake, fermentation and anaerobic test values. On the basis of the results of several anaerobic tests, the methane production rate k (year{sup −1}) was evaluated. k ranged from 0.436 to 0.308 year{sup −1} and the bio-methane potential from 37 to 12 N m{sup 3}/tonne, respectively, for the MSOF with 0 and 16 weeks of treatment. Energy recovery from landfill gas ranged from about 11 to 90 kW h per tonne of disposed MSOF depending on the different scenario investigated. Life cycle analysis showed that the scenario with 0 weeks of pre-treatment has the highest weighted global impact even if opposite results were obtained with respect to the single impact criteria. MSOF pre-treatment periods longer than 4 weeks showed rather negligible variation

  9. Methane emissions from MBT landfills

    SciTech Connect

    Heyer, K.-U. Hupe, K.; Stegmann, R.

    2013-09-15

    Highlights: • Compilation of methane generation potential of mechanical biological treated (MBT) municipal solid waste. • Impacts and kinetics of landfill gas production of MBT landfills, approach with differentiated half-lives. • Methane oxidation in the waste itself and in soil covers. • Estimation of methane emissions from MBT landfills in Germany. - Abstract: Within the scope of an investigation for the German Federal Environment Agency (“Umweltbundesamt”), the basics for the estimation of the methane emissions from the landfilling of mechanically and biologically treated waste (MBT) were developed. For this purpose, topical research including monitoring results regarding the gas balance at MBT landfills was evaluated. For waste treated to the required German standards, a methane formation potential of approximately 18–24 m{sup 3} CH{sub 4}/t of total dry solids may be expected. Monitoring results from MBT landfills show that a three-phase model with differentiated half-lives describes the degradation kinetics in the best way. This is due to the fact that during the first years of disposal, the anaerobic degradation processes still proceed relatively intensively. In addition in the long term (decades), a residual gas production at a low level is still to be expected. Most of the soils used in recultivation layer systems at German landfills show a relatively high methane oxidation capacity up to 5 l CH{sub 4}/(m{sup 2} h). However, measurements at MBT disposal sites indicate that the majority of the landfill gas (in particular at non-covered areas), leaves the landfill body via preferred gas emission zones (hot spots) without significant methane oxidation. Therefore, rather low methane oxidation factors are recommended for open and temporarily covered MBT landfills. Higher methane oxidation rates can be achieved when the soil/recultivation layer is adequately designed and operated. Based on the elaborated default values, the First Order Decay (FOD

  10. Waste management in the Irkutsk Region, Siberia, Russia: environmental assessment of current practice focusing on landfilling.

    PubMed

    Starostina, Vlada; Damgaard, Anders; Rechberger, Helmut; Christensen, Thomas H

    2014-05-01

    The municipal waste management system of the region of Irkutsk is described and a life cycle assessment (LCA) performed to assess the environmental performance of the system. Annually about 500 000 tons of waste are managed. The waste originates from three sources: household waste (27%), commercial waste (23%) and office & institutional waste (44%). Other waste of unknown composition constitutes 6%. Only 3% of the waste is recycled; 97% of the municipal waste is disposed of at the old Alexandrovsky landfill. The environmental impact from the current system is dominated by the landfill, which has no gas or leachate collection system. The global warming contribution is due to the emission of methane of the order of 420 000 tons CO2-equivalents per year. Collection and transport of the waste are insignificant compared with impacts from the landfill. As the old landfill runs out of capacity in a few years, the LCA modelling showed that introduction of a new and modern landfill with gas and leachate collection could improve the performance of the waste management system significantly. Collection of landfill gas and utilization for 30 years for electricity production (gas turbine) would reduce the global warming completely and result in a net saving of 100 000 CO2-equivalents per year due to storage of biogenic carbon in the landfill beyond 100 years. Considering other first-order degradation rates for the landfilled organic matter did not overtly affect the results, while assumptions about the top cover oxidation of methane significantly affected the results. This shows the importance of controlling the gas escape from the landfill.

  11. Waste management in the Irkutsk Region, Siberia, Russia: environmental assessment of current practice focusing on landfilling.

    PubMed

    Starostina, Vlada; Damgaard, Anders; Rechberger, Helmut; Christensen, Thomas H

    2014-05-01

    The municipal waste management system of the region of Irkutsk is described and a life cycle assessment (LCA) performed to assess the environmental performance of the system. Annually about 500 000 tons of waste are managed. The waste originates from three sources: household waste (27%), commercial waste (23%) and office & institutional waste (44%). Other waste of unknown composition constitutes 6%. Only 3% of the waste is recycled; 97% of the municipal waste is disposed of at the old Alexandrovsky landfill. The environmental impact from the current system is dominated by the landfill, which has no gas or leachate collection system. The global warming contribution is due to the emission of methane of the order of 420 000 tons CO2-equivalents per year. Collection and transport of the waste are insignificant compared with impacts from the landfill. As the old landfill runs out of capacity in a few years, the LCA modelling showed that introduction of a new and modern landfill with gas and leachate collection could improve the performance of the waste management system significantly. Collection of landfill gas and utilization for 30 years for electricity production (gas turbine) would reduce the global warming completely and result in a net saving of 100 000 CO2-equivalents per year due to storage of biogenic carbon in the landfill beyond 100 years. Considering other first-order degradation rates for the landfilled organic matter did not overtly affect the results, while assumptions about the top cover oxidation of methane significantly affected the results. This shows the importance of controlling the gas escape from the landfill. PMID:24692457

  12. Greenhouse gas emissions from municipal solid waste management in Indian mega-cities: a case study of Chennai landfill sites.

    PubMed

    Jha, Arvind K; Sharma, C; Singh, Nahar; Ramesh, R; Purvaja, R; Gupta, Prabhat K

    2008-03-01

    Municipal solid waste generation rate is over-riding the population growth rate in all mega-cities in India. Greenhouse gas emission inventory from landfills of Chennai has been generated by measuring the site specific emission factors in conjunction with relevant activity data as well as using the IPCC methodologies for CH4 inventory preparation. In Chennai, emission flux ranged from 1.0 to 23.5mg CH4m(-2)h(-1), 6 to 460microg N2Om(-2)h(-1) and 39 to 906mg CO2m(2)h(-1) at Kodungaiyur and 0.9 to 433mg CH4m(-2)h(-1), 2.7 to 1200microg N2Om(-2)h(-1) and 12.3 to 964.4mg CO2m(-2)h(-1) at Perungudi. CH4 emission estimates were found to be about 0.12Gg in Chennai from municipal solid waste management for the year 2000 which is lower than the value computed using IPCC, 1996 [IPCC, 1996. Report of the 12th session of the intergovernmental panel of climate change, Mexico City, 1996] methodologies.

  13. Apparatus for gas sorption measurement with integrated gas composition measurement device and gas mixing

    SciTech Connect

    Micklash. II, Kenneth James; Dutton, Justin James; Kaye, Steven

    2014-06-03

    An apparatus for testing of multiple material samples includes a gas delivery control system operatively connectable to the multiple material samples and configured to provide gas to the multiple material samples. Both a gas composition measurement device and pressure measurement devices are included in the apparatus. The apparatus includes multiple selectively openable and closable valves and a series of conduits configured to selectively connect the multiple material samples individually to the gas composition device and the pressure measurement devices by operation of the valves. A mixing system is selectively connectable to the series of conduits and is operable to cause forced mixing of the gas within the series of conduits to achieve a predetermined uniformity of gas composition within the series of conduits and passages.

  14. Landfill mining: Giving garbage a second chance

    SciTech Connect

    Cobb, C.C.; Ruckstuhl, K. )

    1988-08-01

    Some communities face the problems of lack of landfill space and lack of landfill cover dirt. In some cases, existing landfills may be mined to reclaim dirt for use as cover material and to recover space for reuse. Such mining also has the potential of recovering recyclables and incinerator fuels. Machinery to reclaim refuse deposits, and their heterogeneous composted ingredients, was successfully tested at two Florida landfills in June 1987. One of the Florida mining tests, at the Collier County landfill near the city of Naples, had goals of demonstrating an economical mechanical system to separate the depository's ingredients into usable or redisposable components, and to see if the method could enable the county to avoid the expenses associated with permanent closure of a full landfill. This paper describes the history of the Collier County landfill, the equipment and feasibility test, economics, the monitoring of odors, landfill gas, and heavy metals, and results of the test.

  15. Technical potential of electricity production from municipal solid waste disposed in the biggest cities in Brazil: landfill gas, biogas and thermal treatment.

    PubMed

    de Souza, Samuel Nm; Horttanainen, Mika; Antonelli, Jhonatas; Klaus, Otávia; Lindino, Cleber A; Nogueira, Carlos Ec

    2014-10-01

    This article presents an analysis of possibilities for electrical energy production by using municipal solid waste disposed in the biggest Brazilian cities. Currently, the municipal solid waste in Brazil is collected and disposed of at landfills, but there are also other technologies, which in addition to dealing with the garbage can also provide benefits in terms of energy provision. The following scenarios were studied in this work: electricity production from landfill gas (reference scenario); incineration of all municipal solid waste; anaerobic digestion of organic waste and incineration of refuse-derived fuel fractions after being separated in separation plants. According to this study, the biggest cities in Brazil generate about 18.9 million tonnes of municipal solid waste per year (2011), of which 51.5% is biogenic matter. The overall domestic consumption of electricity is 480,120 GWh y(-1) in Brazil and the municipal solid waste incineration in the 16 largest cities in the country could replace 1.8% of it using incinerators. The city of São Paulo could produce 637 GWh y(-1) with landfill gas, 2368 GWh y(-1) with incineration of municipal solid waste and 1177 GWh y(-1) with incineration of refuse-derived fuel. The latter two scenarios could replace 27% and 13.5% of the residential electrical energy consumption in the city. This shows that thermal treatment might be a viable option of waste-to-energy in Brazil.

  16. Technical potential of electricity production from municipal solid waste disposed in the biggest cities in Brazil: landfill gas, biogas and thermal treatment.

    PubMed

    de Souza, Samuel Nm; Horttanainen, Mika; Antonelli, Jhonatas; Klaus, Otávia; Lindino, Cleber A; Nogueira, Carlos Ec

    2014-10-01

    This article presents an analysis of possibilities for electrical energy production by using municipal solid waste disposed in the biggest Brazilian cities. Currently, the municipal solid waste in Brazil is collected and disposed of at landfills, but there are also other technologies, which in addition to dealing with the garbage can also provide benefits in terms of energy provision. The following scenarios were studied in this work: electricity production from landfill gas (reference scenario); incineration of all municipal solid waste; anaerobic digestion of organic waste and incineration of refuse-derived fuel fractions after being separated in separation plants. According to this study, the biggest cities in Brazil generate about 18.9 million tonnes of municipal solid waste per year (2011), of which 51.5% is biogenic matter. The overall domestic consumption of electricity is 480,120 GWh y(-1) in Brazil and the municipal solid waste incineration in the 16 largest cities in the country could replace 1.8% of it using incinerators. The city of São Paulo could produce 637 GWh y(-1) with landfill gas, 2368 GWh y(-1) with incineration of municipal solid waste and 1177 GWh y(-1) with incineration of refuse-derived fuel. The latter two scenarios could replace 27% and 13.5% of the residential electrical energy consumption in the city. This shows that thermal treatment might be a viable option of waste-to-energy in Brazil. PMID:25323146

  17. Mill Seat Landfill Bioreactor Renewable Green Power (NY)

    SciTech Connect

    Barton & Loguidice, P.C.

    2010-01-07

    The project was implemented at the Mill Seat landfill located in the Town of Bergen, Monroe County, New York. The landfill was previously equipped with a landfill gas collection system to collect methane gas produced by the bioreactor landfill and transport it to a central location for end use. A landfill gas to energy facility was also previously constructed at the site, which utilized generator engines, designed to be powered with landfill methane gas, to produce electricity, to be utilized on site and to be sold to the utility grid. The landfill gas generation rate at the site had exceeded the capacity of the existing generators, and the excess landfill gas was therefore being burned at a candlestick flare for destruction. The funded project consisted of the procurement and installation of two (2) additional 800 KW Caterpillar 3516 generator engines, generator sets, switchgear and ancillary equipment.

  18. Quantitative Analysis of Critical Factors for the Climate Impact of Landfill Mining.

    PubMed

    Laner, David; Cencic, Oliver; Svensson, Niclas; Krook, Joakim

    2016-07-01

    Landfill mining has been proposed as an innovative strategy to mitigate environmental risks associated with landfills, to recover secondary raw materials and energy from the deposited waste, and to enable high-valued land uses at the site. The present study quantitatively assesses the importance of specific factors and conditions for the net contribution of landfill mining to global warming using a novel, set-based modeling approach and provides policy recommendations for facilitating the development of projects contributing to global warming mitigation. Building on life-cycle assessment, scenario modeling and sensitivity analysis methods are used to identify critical factors for the climate impact of landfill mining. The net contributions to global warming of the scenarios range from -1550 (saving) to 640 (burden) kg CO2e per Mg of excavated waste. Nearly 90% of the results' total variation can be explained by changes in four factors, namely the landfill gas management in the reference case (i.e., alternative to mining the landfill), the background energy system, the composition of the excavated waste, and the applied waste-to-energy technology. Based on the analyses, circumstances under which landfill mining should be prioritized or not are identified and sensitive parameters for the climate impact assessment of landfill mining are highlighted. PMID:27282202

  19. Effect of an uncontrolled fire and the subsequent fire fight on the chemical composition of landfill leachate.

    PubMed

    Oygard, Joar Karsten; Måge, Amund; Gjengedal, Elin; Svane, Tore

    2005-01-01

    Landfill leachates sampled during and after an accidental landfill fire were analysed and the levels of selected metals and chemical compounds compared to those occurring in the leachate under normal conditions. The fire at the landfill site was put out by excavation and cooling by use of water. The investigation during the fire and fire fight revealed a moderate increase in the level of nitrogen and also in pH and conductivity. Heavy metals and COD in the leachate showed considerably increased levels. In general, the determined variables appeared to normalise within one week after the fire was extinguished. It can be concluded that landfill fires extinguished by excavation may lead to elevated leachate levels of especially COD and heavy metals, but that this is only a short-term effect. PMID:16009305

  20. Experimental and life cycle assessment analysis of gas emission from mechanically-biologically pretreated waste in a landfill with energy recovery.

    PubMed

    Di Maria, Francesco; Sordi, Alessio; Micale, Caterina

    2013-11-01

    The global gaseous emissions produced by landfilling the Mechanically Sorted Organic Fraction (MSOF) with different weeks of Mechanical Biological Treatment (MBT) was evaluated for an existing waste management system. One MBT facility and a landfill with internal combustion engines fuelled by the landfill gas for electrical energy production operate in the waste management system considered. An experimental apparatus was used to simulate 0, 4, 8 and 16weeks of aerobic stabilization and the consequent biogas potential (Nl/kg) of a large sample of MSOF withdrawn from the full-scale MBT. Stabilization achieved by the waste was evaluated by dynamic oxygen uptake and fermentation tests. Good correlation coefficients (R(2)), ranging from 0.7668 to 0.9772, were found between oxygen uptake, fermentation and anaerobic test values. On the basis of the results of several anaerobic tests, the methane production rate k (year(-1)) was evaluated. k ranged from 0.436 to 0.308year(-1) and the bio-methane potential from 37 to 12Nm(3)/tonne, respectively, for the MSOF with 0 and 16weeks of treatment. Energy recovery from landfill gas ranged from about 11 to 90kWh per tonne of disposed MSOF depending on the different scenario investigated. Life cycle analysis showed that the scenario with 0weeks of pre-treatment has the highest weighted global impact even if opposite results were obtained with respect to the single impact criteria. MSOF pre-treatment periods longer than 4weeks showed rather negligible variation in the global impact of system emissions. PMID:23910244

  1. Theory for a gas composition sensor based on acoustic properties.

    PubMed

    Phillips, Scott; Dain, Yefim; Lueptow, Richard M

    2003-01-01

    Sound travelling through a gas propagates at different speeds and its intensity attenuates to different degrees depending upon the composition of the gas. Theoretically, a real-time gaseous composition sensor could be based on measuring the sound speed and the acoustic attenuation. To this end, the speed of sound was modelled using standard relations, and the acoustic attenuation was modelled using the theory for vibrational relaxation of gas molecules. The concept for a gas composition sensor is demonstrated theoretically for nitrogen-methane-water and hydrogen-oxygen-water mixtures. For a three-component gas mixture, the measured sound speed and acoustic attenuation each define separate lines in the composition plane of two of the gases. The intersection of the two lines defines the gas composition. It should also be possible to use the concept for mixtures of more than three components, if the nature of the gas composition is known to some extent. PMID:14552356

  2. 30 CFR 36.26 - Composition of exhaust gas.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Composition of exhaust gas. 36.26 Section 36.26... EQUIPMENT Construction and Design Requirements § 36.26 Composition of exhaust gas. (a) Preliminary engine... the engine shall be adjusted so that the undiluted exhaust gas shall contain not more than...

  3. 30 CFR 36.26 - Composition of exhaust gas.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Composition of exhaust gas. 36.26 Section 36.26... EQUIPMENT Construction and Design Requirements § 36.26 Composition of exhaust gas. (a) Preliminary engine... the engine shall be adjusted so that the undiluted exhaust gas shall contain not more than...

  4. 30 CFR 36.26 - Composition of exhaust gas.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Composition of exhaust gas. 36.26 Section 36.26... EQUIPMENT Construction and Design Requirements § 36.26 Composition of exhaust gas. (a) Preliminary engine... the engine shall be adjusted so that the undiluted exhaust gas shall contain not more than...

  5. Quantification of landfill methane using modified Intergovernmental Panel on Climate Change's waste model and error function analysis.

    PubMed

    Govindan, Siva Shangari; Agamuthu, P

    2014-10-01

    Waste management can be regarded as a cross-cutting environmental 'mega-issue'. Sound waste management practices support the provision of basic needs for general health, such as clean air, clean water and safe supply of food. In addition, climate change mitigation efforts can be achieved through reduction of greenhouse gas emissions from waste management operations, such as landfills. Landfills generate landfill gas, especially methane, as a result of anaerobic degradation of the degradable components of municipal solid waste. Evaluating the mode of generation and collection of landfill gas has posted a challenge over time. Scientifically, landfill gas generation rates are presently estimated using numerical models. In this study the Intergovernmental Panel on Climate Change's Waste Model is used to estimate the methane generated from a Malaysian sanitary landfill. Key parameters of the model, which are the decay rate and degradable organic carbon, are analysed in two different approaches; the bulk waste approach and waste composition approach. The model is later validated using error function analysis and optimum decay rate, and degradable organic carbon for both approaches were also obtained. The best fitting values for the bulk waste approach are a decay rate of 0.08 y(-1) and degradable organic carbon value of 0.12; and for the waste composition approach the decay rate was found to be 0.09 y(-1) and degradable organic carbon value of 0.08. From this validation exercise, the estimated error was reduced by 81% and 69% for the bulk waste and waste composition approach, respectively. In conclusion, this type of modelling could constitute a sensible starting point for landfills to introduce careful planning for efficient gas recovery in individual landfills.

  6. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    SciTech Connect

    Don Augenstein

    1999-01-11

    ''Conventional'' waste landfills emit methane, a potent greenhouse gas, in quantities such that landfill methane is a major factor in global climate change. Controlled landfilling is a novel approach to manage landfills for rapid completion of total gas generation, maximizing gas capture and minimizing emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated and brought to much earlier completion by improving conditions for biological processes (principally moisture levels) in the landfill. Gas recovery efficiency approaches 100% through use of surface membrane cover over porous gas recovery layers operated at slight vacuum. A field demonstration project's results at the Yolo County Central Landfill near Davis, California are, to date, highly encouraging. Two major controlled landfilling benefits would be the reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role in reduction of US greenhouse gas emissions.

  7. Engineered Municipal Waste Landfills: Climate Significance, Benefits, and some Landfill "Geophysics"

    NASA Astrophysics Data System (ADS)

    Augenstein, D.; Yazdani, R.

    2002-12-01

    Municipal Solid Waste (MSW) landfills have unique features: Wastes worldwide emit biogenic methane to the atmosphere of magnitude comparable to the total atmospheric buildup between 1980 and 1990. Carbon sequestered in landfills is large in geologic terms Management of decomposition in landfilled waste is desirable: (a) Control of waste decomposition and methane promises over tenfold cheaper greenhouse gas abatement compared to most other greenhouse gas abatement strategies. This is due in part to carbon sequestration and landfill gas energy offset of fossil fuel consumption (b) Landfill gas energy potential worldwide, is up to 1% of world energy. Use of landfill gas conserves a resource otherwise wasted (c) Monetary benefits of landfill life extension from decomposition and rapid volume reduction can be quite attractive This is a benefit for the US, where landfills are increasingly difficult and expensive to site. (d) Landfills containing mixed waste can be significant sources of atmospheric and groundwater pollutants needing control. Control is possible from advancing landfill management approaches (e) The stabilization of waste lessens pollutant risk and needs for costly long-term landfill aftercare. Greater control of landfill decomposition has been advocated in the form of "controlled" or "bioreactor" landfills. (SWANA, 1999; Reinhart and Townsend, 1996). Field trials are encouraging by several environmental/monetary criteria. Control of moisture and temperature have given fivefold or more acceleration of methane generation (Augenstein et al, 1998, 2000). There has been rapid volume loss of the landfilled waste as well, with conversion of waste organics to gas. Many trials over years have shown potential for abatement of pollutants in landfill leachate. Demonstration work by the solid waste management community attests to the benefits potential. Increasing field demonstrations, have been accompanied by observation and/or solution of several issues. As noted

  8. Venice Park landfill: Working with the community

    SciTech Connect

    McAdams, C.L.

    1993-09-01

    Venice Park landfill was one of the first sites to be permitted under Michigan's proposed Public Act 641. PA 641 essentially changed the rules and regulations for landfills from the simple design of digging a hole and filling it. It also upgraded standards to those that are more sophisticated, including liners, leachate collection systems, and gas extraction systems. In 1992, methane gas from the landfill was collected into wells drilled into the trash varying in depth from 30-50 feet in depth. A vacuum pulls the gas from the trash into the wells, then through a piping system. The landfill uses about 80-100 kilowatts in-house. The remainder of the gas is sold to Consumers Power Co. which uses landfill gas to supply power to homes.

  9. Bringing new life to old landfills

    SciTech Connect

    Rabasca, L.

    1996-01-01

    On the West Coast, Waste Management, Inc. is bringing new life to old landfills. The Bradley Landfill in Sun Valley, CA, just outside of Los Angeles, is being transformed into a recycling park, while a few hundred miles north, in the San Francisco Bay Area, an old landfill is now home to a transfer station and recycling center. WMI began transforming the landfill in the early 1990s.The first change was to process wood and green waste rather than landfilling it. In 1993, WMI added a sorting facility, and in 1994, after the Jan. 17 Northridge earthquake, the company added a construction and demolition debris (C and D) facility. There also is a landfill gas collection facility on the site. In the future, WMI hopes to add the following facilities: composting, railhaul, alternative fuels production, tire processing, and soil remediation. WMI also hopes several companies that use recycled materials as feedstock will build their plants at the landfill.

  10. Release and fate of fluorocarbons in a shredder residue landfill cell: 2. Field investigations.

    PubMed

    Scheutz, Charlotte; Fredenslund, Anders M; Nedenskov, Jonas; Kjeldsen, Peter

    2010-11-01

    The shredder residues from automobiles, home appliances and other metal containing products are often disposed in landfills, as recycling technologies for these materials are not common in many countries. Shredder waste contains rigid and soft foams from cushions and insulation panels blown with fluorocarbons. The objective of this study was to determine the gas composition, attenuation, and emission of fluorocarbons in a monofill shredder residue landfill cell by field investigation. Landfill gas generated within the shredder waste primarily consisted of CH(4) (27%) and N(2) (71%), without CO(2), indicating that the gas composition was governed by chemical reactions in combination with anaerobic microbial reactions. The gas generated also contained different fluorocarbons (up to 27 μg L(-1)). The presence of HCFC-21 and HCFC-31 indicated that anaerobic degradation of CFC-11 occurred in the landfill cell, as neither of these compounds has been produced for industrial applications. This study demonstrates that a landfill cell containing shredder waste has a potential for attenuating CFC-11 released from polyurethane (PUR) insulation foam in the cell via aerobic and anaerobic biodegradation processes. In deeper, anaerobic zones of the cell, reductive dechlorination of CFCs to HCFCs was evident, while in the shallow, oxic zones, there was a high potential for biooxidation of both methane and lesser chlorinated fluorocarbons. These findings correlated well with both laboratory results (presented in a companion paper) and surface emission measurements that, with the exception from a few hot spots, indicated that surface emissions were negative or below detection. PMID:20444588

  11. Quantifying Uncontrolled Air Emissions from Two Florida Landfills

    EPA Science Inventory

    Landfill gas emissions, if left uncontrolled, contribute to air toxics, climate change, trospospheric ozone, and urban smog. Measuring emissions from landfills presents unique challenges due to the large and variable source area, spatial and temporal variability of emissions, and...

  12. Estimation of landfill emission lifespan using process oriented modeling

    SciTech Connect

    Ustohalova, Veronika . E-mail: veronika.ustohalova@uni-essen.de; Ricken, Tim; Widmann, Renatus

    2006-07-01

    Depending on the particular pollutants emitted, landfills may require service activities lasting from hundreds to thousands of years. Flexible tools allowing long-term predictions of emissions are of key importance to determine the nature and expected duration of maintenance and post-closure activities. A highly capable option represents predictions based on models and verified by experiments that are fast, flexible and allow for the comparison of various possible operation scenarios in order to find the most appropriate one. The intention of the presented work was to develop a experimentally verified multi-dimensional predictive model capable of quantifying and estimating processes taking place in landfill sites where coupled process description allows precise time and space resolution. This constitutive 2-dimensional model is based on the macromechanical theory of porous media (TPM) for a saturated thermo-elastic porous body. The model was used to simulate simultaneously occurring processes: organic phase transition, gas emissions, heat transport, and settlement behavior on a long time scale for municipal solid waste deposited in a landfill. The relationships between the properties (composition, pore structure) of a landfill and the conversion and multi-phase transport phenomena inside it were experimentally determined. In this paper, we present both the theoretical background of the model and the results of the simulations at one single point as well as in a vertical landfill cross section.

  13. Compositional effects on leaching of stain-guarded (perfluoroalkyl and polyfluoroalkyl substance-treated) carpet in landfill leachate.

    PubMed

    Kim, Minhee; Li, Loretta Y; Grace, John R; Benskin, Jonathan P; Ikonomou, Michael G

    2015-06-01

    Perfluoroalkyl and polyfluoroalkyl substances (PFASs) from stain-guard treated carpets in landfills continue to be released into the environment. To understand the leaching of PFASs from carpets to landfill leachate as a function of environmental factors, leaching concentrations of ten perfluoroalkyl carboxylic acids and four perfluoroalkyl sulfonic acids were quantified for different pHs, contact times, mixing speeds, and temperatures. Partitioning from carpet to leachate and distilled water at different pHs showed negligible differences. The total concentration of leaching PFASs in distilled water was approximately 1 ng L(-1) higher than in landfill leachate, indicating that the presence of multivalent cations in leachate could have a negative effect on leaching of PFASs. For all PFASs monitored, leaching increased with increasing contact time and temperature. Perfluorohexanoic and perfluoroheptanoic acids experienced the largest increases with contact time and temperature. Gibbs free energy (ΔG > 0), enthalpy (ΔH > 0), and entropy energy (ΔS < 0) indicated that PFAS leaching from carpet was dominantly controlled by entropy-driven processes and did not differ significantly among individual PFASs. PFAS concentrations in leachate with rotation of an end-over-end contactor were higher than under static conditions, but otherwise, varying the rotation speed had negligible influence. The results provide useful information for management of discarded stain-guard carpets in landfills.

  14. Compositional effects on leaching of stain-guarded (perfluoroalkyl and polyfluoroalkyl substance-treated) carpet in landfill leachate.

    PubMed

    Kim, Minhee; Li, Loretta Y; Grace, John R; Benskin, Jonathan P; Ikonomou, Michael G

    2015-06-01

    Perfluoroalkyl and polyfluoroalkyl substances (PFASs) from stain-guard treated carpets in landfills continue to be released into the environment. To understand the leaching of PFASs from carpets to landfill leachate as a function of environmental factors, leaching concentrations of ten perfluoroalkyl carboxylic acids and four perfluoroalkyl sulfonic acids were quantified for different pHs, contact times, mixing speeds, and temperatures. Partitioning from carpet to leachate and distilled water at different pHs showed negligible differences. The total concentration of leaching PFASs in distilled water was approximately 1 ng L(-1) higher than in landfill leachate, indicating that the presence of multivalent cations in leachate could have a negative effect on leaching of PFASs. For all PFASs monitored, leaching increased with increasing contact time and temperature. Perfluorohexanoic and perfluoroheptanoic acids experienced the largest increases with contact time and temperature. Gibbs free energy (ΔG > 0), enthalpy (ΔH > 0), and entropy energy (ΔS < 0) indicated that PFAS leaching from carpet was dominantly controlled by entropy-driven processes and did not differ significantly among individual PFASs. PFAS concentrations in leachate with rotation of an end-over-end contactor were higher than under static conditions, but otherwise, varying the rotation speed had negligible influence. The results provide useful information for management of discarded stain-guard carpets in landfills. PMID:25985932

  15. Seasonal greenhouse gas emissions (methane, carbon dioxide, nitrous oxide) from engineered landfills: Daily, intermediate, and final California cover soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We quantified the seasonal variability of CH4, CO2, and N2O emissions from fresh refuse and daily, intermediate, and final cover materials at two California landfills. Fresh refuse fluxes (g m-2 d-1) averaged CH4 0.053[+/-0.03], CO2 135[+/-117], and N2O 0.063[+/-0.059]. Average CH4 emissions across ...

  16. The environmental comparison of landfilling vs. incineration of MSW accounting for waste diversion.

    PubMed

    Assamoi, Bernadette; Lawryshyn, Yuri

    2012-05-01

    This study evaluates the environmental performance and discounted costs of the incineration and landfilling of municipal solid waste that is ready for the final disposal while accounting for existing waste diversion initiatives, using the life cycle assessment (LCA) methodology. Parameters such as changing waste generation quantities, diversion rates and waste composition were also considered. Two scenarios were assessed in this study on how to treat the waste that remains after diversion. The first scenario is the status quo, where the entire residual waste was landfilled whereas in the second scenario approximately 50% of the residual waste was incinerated while the remainder is landfilled. Electricity was produced in each scenario. Data from the City of Toronto was used to undertake this study. Results showed that the waste diversion initiatives were more effective in reducing the organic portion of the waste, in turn, reducing the net electricity production of the landfill while increasing the net electricity production of the incinerator. Therefore, the scenario that incorporated incineration performed better environmentally and contributed overall to a significant reduction in greenhouse gas emissions because of the displacement of power plant emissions; however, at a noticeably higher cost. Although landfilling proves to be the better financial option, it is for the shorter term. The landfill option would require the need of a replacement landfill much sooner. The financial and environmental effects of this expenditure have yet to be considered. PMID:22099926

  17. The environmental comparison of landfilling vs. incineration of MSW accounting for waste diversion.

    PubMed

    Assamoi, Bernadette; Lawryshyn, Yuri

    2012-05-01

    This study evaluates the environmental performance and discounted costs of the incineration and landfilling of municipal solid waste that is ready for the final disposal while accounting for existing waste diversion initiatives, using the life cycle assessment (LCA) methodology. Parameters such as changing waste generation quantities, diversion rates and waste composition were also considered. Two scenarios were assessed in this study on how to treat the waste that remains after diversion. The first scenario is the status quo, where the entire residual waste was landfilled whereas in the second scenario approximately 50% of the residual waste was incinerated while the remainder is landfilled. Electricity was produced in each scenario. Data from the City of Toronto was used to undertake this study. Results showed that the waste diversion initiatives were more effective in reducing the organic portion of the waste, in turn, reducing the net electricity production of the landfill while increasing the net electricity production of the incinerator. Therefore, the scenario that incorporated incineration performed better environmentally and contributed overall to a significant reduction in greenhouse gas emissions because of the displacement of power plant emissions; however, at a noticeably higher cost. Although landfilling proves to be the better financial option, it is for the shorter term. The landfill option would require the need of a replacement landfill much sooner. The financial and environmental effects of this expenditure have yet to be considered.

  18. Case study of landfill reclamation at a Florida landfill site.

    PubMed

    Jain, Pradeep; Townsend, Timothy G; Johnson, Patrick

    2013-01-01

    A landfill reclamation project was considered to recover landfill airspace and soil, reduce future groundwater impacts by removing the waste buried in the unlined area, and optimize airspace use at the site. A phased approach was utilized to evaluate the technical and economic feasibility of the reclamation project; based on the results of these evaluations, approximately 6.8 ha of the unlined cells were reclaimed. Approximately 371,000 in-place cubic meters of waste was mined from 6.8 ha in this project. Approximately 230,600 cubic meters of net airspace was recovered due to beneficial use of the recovered final cover soil and reclaimed soil as intermediate and daily cover soil, respectively, for the current landfill operations. This paper presents the researchers' landfill reclamation project experience, including a summary of activities pertaining to reclamation operations, an estimation of reclamation rates achieved during the project, project costs and benefits, and estimated composition of the reclaimed materials.

  19. 30 CFR 36.26 - Composition of exhaust gas.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Composition of exhaust gas. 36.26 Section 36.26 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND... EQUIPMENT Construction and Design Requirements § 36.26 Composition of exhaust gas. (a) Preliminary...

  20. 30 CFR 36.26 - Composition of exhaust gas.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Composition of exhaust gas. 36.26 Section 36.26 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND... EQUIPMENT Construction and Design Requirements § 36.26 Composition of exhaust gas. (a) Preliminary...

  1. Differences in volatile methyl siloxane (VMS) profiles in biogas from landfills and anaerobic digesters and energetics of VMS transformations

    SciTech Connect

    Tansel, Berrin Surita, Sharon C.

    2014-11-15

    Highlights: • In the digester gas, D4 and D5 comprised the 62% and 27% if siloxanes, respectively. • In landfill gas, the bulk of siloxanes were TMSOH (58%) followed by D4 (17%). • Methane utilization may be a possible mechanism for TMSOH formation in the landfills. • The geometric configurations of D4 and D5 molecules make them very stable. - Abstract: The objectives of this study were to compare the types and levels of volatile methyl siloxanes (VMS) present in biogas generated in the anaerobic digesters and landfills, evaluate the energetics of siloxane transformations under anaerobic conditions, compare the conditions in anaerobic digesters and municipal solid waste (MSW) landfills which result in differences in siloxane compositions. Biogas samples were collected at the South District Wastewater Treatment Plant and South Dade Landfill in Miami, Florida. In the digester gas, D4 and D5 comprised the bulk of total siloxanes (62% and 27%, respectively) whereas in the landfill gas, the bulk of siloxanes were trimethylsilanol (TMSOH) (58%) followed by D4 (17%). Presence of high levels of TMSOH in the landfill gas indicates that methane utilization may be a possible reaction mechanism for TMSOH formation. The free energy change for transformation of D5 and D4 to TMSOH either by hydrogen or methane utilization are thermodynamically favorable. Either hydrogen or methane should be present at relatively high concentrations for TMSOH formation which explains the high levels present in the landfill gas. The high bond energy and bond distance of the Si–O bond, in view of the atomic sizes of Si and O atoms, indicate that Si atoms can provide a barrier, making it difficult to break the Si–O bonds especially for molecules with specific geometric configurations such as D4 and D5 where oxygen atoms are positioned inside the frame formed by the large Si atoms which are surrounded by the methyl groups.

  2. Tunable Composite Membranes for Gas Separations.

    SciTech Connect

    Ferraris, J.P.; Balkus, K.J. Jr.; Musselman, I.H.

    1997-07-01

    Solution cast membranes of poly(3-dodecylthiophene) (PDDT) were studied for the room temperature separation of N{sub 2}, 0{sub 2}, and C0{sub 2} procedure for fabricating reproducible, smooth, uniformly thick (-35-pm), defect-free membranes was established. Permeability values were measured for as-cast PDDT membranes (PO{sub 2} = 9.4, PN{sub 2} = 20.2, PCO{sub 2} = 88. 2 Barrers) and selectivity values were calculated (XO{sub 2}/N{sub 2} = 2.2, XC0{sub 2}/N{sub 2} = 9.4). Chemically induced doping (-23%) with SbCI5 resulte in a decrease in permeability (PN{sub 2} = 3.5, P0{sub 2} =10.5, PCO{sub 2} = 48.5 Barrers) and a corresponding increase in permselectivity (X 0{sub 2}/N{sub 2} = 0, (xCO{sub 2}/N{sub 2} =14.0)). Membrane undoping with hydrazine partially reversed these trends (PN{sub 2} = 5.4, P0{sub 2} = 15.1, PCO{sub 2} = 62.9 Barrers), (XO{sub 2}/N{sub 2} = 2.8), (XCO{sub 2}/N{sub 2} =I 1. 6). The chemical composition cast, doped, and undoped PDDT membranes were determined using elemental analysis and energy dispersive x-ray spectrometry. Membrane microstructure was investigated by optical microscopy, TappingModeTM atomic force microscopy and scanning electron microscopy. The composition and microscopy results were correlated with changes in gas-transport properties. Two papers were presented at the Meeting of the North American Membranes Society, (June 2-4,1997, Baltimore, MD).

  3. Emissions of C&D refuse in landfills: a European case.

    PubMed

    López, Ana; Lobo, Amaya

    2014-08-01

    A field study was developed in a new landfill for refuse from construction and demolition (C&D) material recovery plants of small size (4 Ha.) in Europe, with the aim of evaluating the liquid and gas emissions in this type of facility at a large scale. It included characterization of the materials, monitoring leachate and gas quantity and composition. Besides thermometers, piezometers and sampling ports were placed in several points within the waste. This paper presents the data obtained for five years of the landfill life. The materials disposed were mainly made up of wood and concrete, similar to other C&D debris sites, but the amount of gypsum drywall (below 3% of the waste) was significantly smaller than other available studies, where percentages above 20% had been reported. Leachate contained typical C&D pollutants, such as different inorganic ions and metals, some of which exceeded other values reported in the literature (conductivity, ammonium, lead and arsenic). The small net precipitation in the area and the leachate recirculation into the landfill surface help explain these higher concentrations, thus highlighting the impact of liquid to solid (L/S) ratio on leachate characteristics. In contrast to previous studies, neither odor nuisances nor significant landfill gas over the surface were detected. However, gas samples taken from the landfill inside revealed sulfate reducing and methanogenic activity. PMID:24824964

  4. Emissions of C&D refuse in landfills: a European case.

    PubMed

    López, Ana; Lobo, Amaya

    2014-08-01

    A field study was developed in a new landfill for refuse from construction and demolition (C&D) material recovery plants of small size (4 Ha.) in Europe, with the aim of evaluating the liquid and gas emissions in this type of facility at a large scale. It included characterization of the materials, monitoring leachate and gas quantity and composition. Besides thermometers, piezometers and sampling ports were placed in several points within the waste. This paper presents the data obtained for five years of the landfill life. The materials disposed were mainly made up of wood and concrete, similar to other C&D debris sites, but the amount of gypsum drywall (below 3% of the waste) was significantly smaller than other available studies, where percentages above 20% had been reported. Leachate contained typical C&D pollutants, such as different inorganic ions and metals, some of which exceeded other values reported in the literature (conductivity, ammonium, lead and arsenic). The small net precipitation in the area and the leachate recirculation into the landfill surface help explain these higher concentrations, thus highlighting the impact of liquid to solid (L/S) ratio on leachate characteristics. In contrast to previous studies, neither odor nuisances nor significant landfill gas over the surface were detected. However, gas samples taken from the landfill inside revealed sulfate reducing and methanogenic activity.

  5. Investigation of greenhouse gas emissions from a landfill site and agriculture in the UK by deployment of an in-situ FTIR

    NASA Astrophysics Data System (ADS)

    Sonderfeld, Hannah; Humpage, Neil; Jeanjean, Antoine; Leigh, Roland; Allen, Grant; Boesch, Hartmut

    2016-04-01

    The main greenhouse gases (GHG) emitted by human activities in the UK are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Understanding and quantifying their emissions is essential to monitor and guide emission reduction measures. The GAUGE (Greenhouse gAs Uk and Global Emissions) project funded by NERC aims to improve the knowledge of the UK GHG budget by an extensive measurement program. In this presentation, we focus on two important sources of these GHG: Waste and agricultural sector. We are presenting data from the deployment of an in-situ FTIR (Ecotech) for continuous and simultaneous sampling of CO2, CH4, N2O and CO with a high time resolution in the order of minutes. During a two week field campaign at a landfill site near Ipswich in August 2014, measurements were taken within a radius of 320 m of the uncovered and active area of the landfill, which was still filled with new incoming waste. The data are analysed in detail for emission ratios of CH4 to CO2. Thereby a consistent ratio in favour of CO2 is found for these emissions. We have applied a computation fluid dynamics (CFD) model, constrained with local wind measurements and a detailed topographic map of the landfill site, to the in-situ concentration data to calculate emission fluxes of the active site. Since October 2014 the FTIR has been sampling from a church tower in Glatton as part of a near surface sampling network in East Anglia focusing on regional GHG emissions from agriculture. The site is mainly influenced by south westerly winds. A clear diurnal cycle is observed in summer for CO2, CH4 and N2O, which is less pronounced in the winter months. A simulation of the methane and nitrous oxide concentrations through application of the NAME model to the EDGAR and NAEI emission inventories illustrates some shortcomings in the available emission inventories for the probed region.

  6. In situ denitrification in controlled landfill systems

    SciTech Connect

    Onay, T.T.; Pohland, F.G.

    1996-11-01

    The characteristics of leachate from landfill disposal sites vary according to the operational stage of the landfill. Leachates from old landfills are often rich in ammonia nitrogen due to the hydrolysis and fermentation of nitrogenous fractions of biodegradable refuse substrates. The relative concentration accumulating as stabilization progresses is also influenced by washout as leachate is collected and removed for external treatment. However, in landfills operated as bioreactors with leachate containment, collection and in situ recirculation to accelerate decomposition of readily available organic fractions of the refuse, leachate ammonia nitrogen concentrations may accumulate to much higher levels. High leachate ammonia nitrogen concentrations in landfill leachate have been reported, resulting in separate treatment challenges if direct discharge to either land or receiving waters is practiced. External treatment options for landfill leachate may involve complex physical-chemical and/or biological processes for removal of both high-strength organic and inorganic fractions, including nitrogen. Such separate leachate treatment systems are often costly and difficult to control on a continuum. Therefore, this study focused on the investigation of landfill ammonia nitrogen generation patterns, and the potential for its in situ attenuation and conversion in landfills constructed to permit sequential nitrification and denitrification using leachate recirculation. Accordingly, the landfill is constructed and operated as a controlled bioreactor system, with opportunity to convert ammonia to nitrate by nitrification and nitrate to nitrogen gas by denitrification. The results presented in this paper focus on in situ landfill denitrification of nitrified ammonia.

  7. Methane oxidation in simulated landfill cover soil environments

    SciTech Connect

    Visscher, A. de; Thomas, D.; Boeckx, P.; Cleemput, O. van

    1999-06-01

    Methane is an important greenhouse gas. Its contribution to the enhanced global warming is estimated at 12%. A considerable fraction of the methane that is produced by landfills is oxidized by its covering soil before it can reach the atmosphere. This process was studied in soil columns that simulate landfill cover soil environments. The methane uptake was followed as a function of time. In soils of agricultural origin, a maximum value of 10.7 mol m{sup {minus}2}{sub column} d{sup {minus}1} was observed. Mixing sugar beet leaves with the soil led to a temporary stimulation of the methane oxidation rate, whereas a wheat straw amendment led to permanent stimulation. Soil originating from a real landfill cover oxidized on the order of 15 mol m{sup {minus}2}{sub column} d{sup {minus}1}, the highest value found in the literature to date. The soil gas composition was studied as a function of depth. With a new batch incubation technique, methane oxidation kinetics were determined in samples taken from the soil column. By combining this kinetic data with the soil gas composition data, the actively methane oxidizing zone in the soil column could be determined and an in situ assessment of oxygen limitation could be performed. Methane oxidation takes place mainly in the top 30 cm of the covering soil.

  8. Landfill aeration for emission control before and during landfill mining.

    PubMed

    Raga, Roberto; Cossu, Raffaello; Heerenklage, Joern; Pivato, Alberto; Ritzkowski, Marco

    2015-12-01

    The landfill of Modena, in northern Italy, is now crossed by the new high velocity railway line connecting Milan and Bologna. Waste was completely removed from a part of the landfill and a trench for the train line was built. With the aim of facilitating excavation and further disposal of the material extracted, suitable measures were defined. In order to prevent undesired emissions into the excavation area, the aerobic in situ stabilisation by means of the Airflow technology took place before and during the Landfill Mining. Specific project features involved the pneumatic leachate extraction from the aeration wells (to keep the leachate table low inside the landfill and increase the volume of waste available for air migration) and the controlled moisture addition into a limited zone, for a preliminary evaluation of the effects on process enhancement. Waste and leachate were periodically sampled in the landfill during the aeration before the excavation, for quality assessment over time; the evolution of biogas composition in the landfill body and in the extraction system for different plant set-ups during the project was monitored, with specific focus on uncontrolled migration into the excavation area. Waste biological stability significantly increased during the aeration (waste respiration index dropped to 33% of the initial value after six months). Leachate head decreased from 4 to 1.5m; leachate recirculation tests proved the beneficial effects of moisture addition on temperature control, without hampering waste aerobization. Proper management of the aeration plant enabled the minimization of uncontrolled biogas emissions into the excavation area.

  9. Assessing methods to estimate emissions of non-methane organic compounds from landfills.

    PubMed

    Saquing, Jovita M; Chanton, Jeffrey P; Yazdani, Ramin; Barlaz, Morton A; Scheutz, Charlotte; Blake, Don R; Imhoff, Paul T

    2014-11-01

    The non-methane organic compound (NMOC) emission rate is used to assess compliance with landfill gas emission regulations by the United States Environmental Protection Agency (USEPA). A recent USEPA Report (EPA/600/R-11/033) employed a ratio method to estimate speciated NMOC emissions (i.e., individual NMOC emissions): speciated NMOC emissions=measured methane (CH4) emission multiplied by the ratio of individual NMOCs concentration relative to CH4 concentration (C(NMOCs)/C(CH4)) in the landfill header gas. The objectives of this study were to (1) evaluate the efficacy of the ratio method in estimating speciated NMOC flux from landfills; (2) determine for what types of landfills the ratio method may be in error and why, using recent field data to quantify the spatial variation of (C(NMOCs)/C(CH4)) in landfills; and (3) formulate alternative models for estimating NMOC emissions from landfills for cases in which the ratio method results in biased estimates. This study focuses on emissions through landfill covers measured with flux chambers and evaluates the utility of the ratio method for estimating NMOC emission through this pathway. Evaluation of the ratio method was performed using CH4 and speciated NMOC concentration and flux data from 2012/2013 field sampling of four landfills, an unpublished landfill study, and literature data from three landfills. The ratio method worked well for landfills with thin covers (<40 cm), predicting composite NMOC flux (as hexane-C) to within a factor of 10× for 13 out of 15 measurements. However, for thick covers (⩾40 cm) the ratio method overestimated NMOC emissions by ⩾10× for 8 out of 10 measurements. Alternative models were explored incorporating other chemical properties into the ratio method. A molecular weight squared (MW)(2)-modified ratio equation was shown to best address the tendency of the current ratio method to overestimate NMOC fluxes for thick covers. While these analyses were only performed using NMOC fluxes

  10. Assessing methods to estimate emissions of non-methane organic compounds from landfills.

    PubMed

    Saquing, Jovita M; Chanton, Jeffrey P; Yazdani, Ramin; Barlaz, Morton A; Scheutz, Charlotte; Blake, Don R; Imhoff, Paul T

    2014-11-01

    The non-methane organic compound (NMOC) emission rate is used to assess compliance with landfill gas emission regulations by the United States Environmental Protection Agency (USEPA). A recent USEPA Report (EPA/600/R-11/033) employed a ratio method to estimate speciated NMOC emissions (i.e., individual NMOC emissions): speciated NMOC emissions=measured methane (CH4) emission multiplied by the ratio of individual NMOCs concentration relative to CH4 concentration (C(NMOCs)/C(CH4)) in the landfill header gas. The objectives of this study were to (1) evaluate the efficacy of the ratio method in estimating speciated NMOC flux from landfills; (2) determine for what types of landfills the ratio method may be in error and why, using recent field data to quantify the spatial variation of (C(NMOCs)/C(CH4)) in landfills; and (3) formulate alternative models for estimating NMOC emissions from landfills for cases in which the ratio method results in biased estimates. This study focuses on emissions through landfill covers measured with flux chambers and evaluates the utility of the ratio method for estimating NMOC emission through this pathway. Evaluation of the ratio method was performed using CH4 and speciated NMOC concentration and flux data from 2012/2013 field sampling of four landfills, an unpublished landfill study, and literature data from three landfills. The ratio method worked well for landfills with thin covers (<40 cm), predicting composite NMOC flux (as hexane-C) to within a factor of 10× for 13 out of 15 measurements. However, for thick covers (⩾40 cm) the ratio method overestimated NMOC emissions by ⩾10× for 8 out of 10 measurements. Alternative models were explored incorporating other chemical properties into the ratio method. A molecular weight squared (MW)(2)-modified ratio equation was shown to best address the tendency of the current ratio method to overestimate NMOC fluxes for thick covers. While these analyses were only performed using NMOC fluxes

  11. The Application Of Biofilter System For Reduction Of Methane Emissions From Modern Sanitary Landfills

    NASA Astrophysics Data System (ADS)

    Sung, K.; Park, S.

    2007-12-01

    Increased atmospheric concentrations of greenhouse gases (GHG) caused by anthropogenic activities has been related to global climate change. Methane, the second most important GHG after CO2, is 21 times more effective at trapping heat than CO2. Therefore, methane emission control is of utmost importance for global warming reduction. To minimize leachate production and protect groundwater resources, modern sanitary landfills are equipped with composite covers and gas collection systems. Methane from modern sanitary landfills is vented directly to the atmosphere, except for some of the largest landfills where it is recovered as energy and burned at the site. However, the efficiency of energy recovery systems in larger landfills is reduced as the amount of CH4 generated from landfill begins to decrease. In this study, the performance of a lab-scale model biofilter system was investigated to treat CH4 gas emitted from modern sanitary landfills by conducting batch and column experiments using landfill cover soil amended with earthworm cast as the filter bed medium. From the batch experiments to measure the influence of moisture content and temperature of the filter medium on CH4 removal capacity of a biofilter system, the optimum moisture content and temperature were found to be 10-15% by weight and 25-35°C, respectively. The column experiment was conducted to measure the influence of inlet CH4 concentration and CH4 loading rate on CH4 removal capacity of a biofilter system. As the inlet CH4 concentration decreased, the percentage of CH4 oxidized increased. Up to a CH4 loading rate of 2785 g CH4 m3 h- 1 (EBRT = 7.7 min), the CH4 removal efficiency of the biofilter was able to reach 100%. Based on the results of the study, the installation of a properly managed biofilter system should be capable of achieving a reduction in atmospheric CH4 emissions from modern sanitary landfills at low CH4 generation stage.

  12. Missing Halocarbon Source? Data from a Recent New England Landfill Field Campaign

    NASA Astrophysics Data System (ADS)

    Hodson, E. L.; Prinn, R.

    2005-12-01

    Anthropogenic emissions of long-lived halocarbons, namely chlorofluorocarbons (CFCs), hydrofluorocarbons (HCFCs), methyl chloroform (CH3CCl3), and carbon tetrachloride (CCl4) represent the largest source of atmospheric chlorine. All of these gases with the exception of the HCFCs are banned under the Montreal Protocol from being produced within the US or imported into the US. Several recent studies indicate that lingering emissions of these compounds are occurring around urban areas in the US. One possible source for these emissions is leakage from landfills. Landfill emissions are not currently considered explicitly in the published industry based global estimations of emissions for these gases. Previous studies have been done in the UK and suggested that this leakage may be significant (on the order of 1 Gg/year in the UK) in comparison with industry emissions estimates, but no measurement based estimates of Montreal Protocol gas emissions from US landfills have been previously reported. To further investigate this idea, flask samples were taken during the winter of 2004 at two Eastern Massachusetts landfills and during the summer of 2004 at four landfills in southwestern Britain. These studies showed more data was needed to create clear regression relationships between the landfill parameters (waste composition, landfill age, and total trash volume) and halocarbon gas emissions of CFC-12, CFC-11, CFC-113, and CH3CCl3. In a movement towards creating the necessary database of measurements, an intensive Fall 2005 landfill measurement campaign was conducted in New England. The results from this campaign will be presented, analyzed and compared to our results from the above two 2004 investigations.

  13. Cleaner Landfills

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Osmotek, Inc. developed the Direct Osmosis treatment system through SBIR funding from Ames Research Center. Using technology originally developed for flight aboard the Space Station, the company brought it to their commercial water purification treatment system, Direct Osmosis. This water purification system uses a direct osmosis process followed by a reverse osmosis treatment. Because the product extracts water from a waste product, Osmotek is marketing the unit for use in landfills. The system can treat leachate (toxic chemicals leached into a water source), by filtering the water and leaving behind the leahcate. The leachate then becomes solidified into substance that can not seep into water.

  14. Corrosion inhibition by control of gas composition during mist drilling

    SciTech Connect

    Hinkebein, T.E.; Snyder, T.L.

    1981-05-01

    Chemical compositional specifications have been generated for inert gases which reduce drill string corrosion when used in conjunction with mist drilling processes. These specifications are based on the assumption that the corrosion rate is dependent on the dissolved gaseous species concentrations. Data taken both from the literature and from a mist drilling field test with nitrogen in Valle Grande, NM, relate corrosion rates to fluid compositions. These solution compositions are then associated with gas phase compositions using equilibrium data available from the literature and material balances. Two sources of gas were considered: cryogenically purified nitrogen from air and exhaust gas from a diesel engine, which contain (in addition to N/sub 2/ and O/sub 2/) CO/sub 2/, NO/sub x/, SO/sub 2/, H/sub 2/O, and CO. A maximum concentration of 50 ppM O/sub 2/ in the gas phase is recommended to alleviate pitting corrosion.

  15. Geochemical processes in landfills

    NASA Astrophysics Data System (ADS)

    Förstner, Ulrich; Kersten, Michael; Wienberg, Reinhard

    The present review focusses on the qualitative long-term perspectives of processes and mechanisms controlling the interactions of critical pollutants with organic and inorganic substrates both in "reactor landfills" and in deposits, which already consist of rock-like material ("final storage quality"). The behavior of pollutants in landfills is determined by the chemistry of interstitial solutions, i.e. by pH and redox conditions, and concentration of inorganic and organic ligands; in "reactor landfills" these conditions are widely variable as a result of biochemical reactions, while "final storage quality" implies less variations of chemical interactions. In both alternatives, however, prediction of short- and long-term effects on groundwater quality should be based on the proportion of "active species" of compounds ("mobility concept"). Qualitative assessment of potentially mobile pollutants may involve a controlled significative intensivation of important parameters such as pH-values. Using sequential extraction rearrangements of specific solid "phases" can be evaluated prior to the actual remobilisation of the pollutant into the dissolved phase. From a geochemical point of view the "reactor landfill" is characterized by labile conditions during the initial aerobic and acid anaerobic phases, the former mainly due to uncontrolled interactions with organic solutes. On the other hand, final storage quality, which is defined by the composition of earth crust material, in most cases is not attained by simple incineration of municipal waste, i.e. by reduction of organic fractions only. There is, in particular, the problem of easily soluble minerals, such as chlorides. Nonetheless the type of inorganic residue deposits will increasingly receive prevalence as a method of final storage for municipal wastes in the future.

  16. Gas Composition Sensing Using Carbon Nanotube Arrays

    NASA Technical Reports Server (NTRS)

    Li, Jing; Meyyappan, Meyya

    2012-01-01

    This innovation is a lightweight, small sensor for inert gases that consumes a relatively small amount of power and provides measurements that are as accurate as conventional approaches. The sensing approach is based on generating an electrical discharge and measuring the specific gas breakdown voltage associated with each gas present in a sample. An array of carbon nanotubes (CNTs) in a substrate is connected to a variable-pulse voltage source. The CNT tips are spaced appropriately from the second electrode maintained at a constant voltage. A sequence of voltage pulses is applied and a pulse discharge breakdown threshold voltage is estimated for one or more gas components, from an analysis of the current-voltage characteristics. Each estimated pulse discharge breakdown threshold voltage is compared with known threshold voltages for candidate gas components to estimate whether at least one candidate gas component is present in the gas. The procedure can be repeated at higher pulse voltages to estimate a pulse discharge breakdown threshold voltage for a second component present in the gas. The CNTs in the gas sensor have a sharp (low radius of curvature) tip; they are preferably multi-wall carbon nanotubes (MWCNTs) or carbon nanofibers (CNFs), to generate high-strength electrical fields adjacent to the tips for breakdown of the gas components with lower voltage application and generation of high current. The sensor system can provide a high-sensitivity, low-power-consumption tool that is very specific for identification of one or more gas components. The sensor can be multiplexed to measure current from multiple CNT arrays for simultaneous detection of several gas components.

  17. Heat management strategies for MSW landfills.

    PubMed

    Yeşiller, Nazli; Hanson, James L; Kopp, Kevin B; Yee, Emma H

    2016-10-01

    Heat is a primary byproduct of landfilling of municipal solid waste. Long-term elevated temperatures have been reported for MSW landfills under different operational conditions and climatic regions around the world. A conceptual framework is presented for management of the heat generated in MSW landfills. Three main strategies are outlined: extraction, regulation, and supplementation. Heat extraction allows for beneficial use of the excess landfill heat as an alternative energy source. Two approaches are provided for the extraction strategy: extracting all of the excess heat above baseline equilibrium conditions in a landfill and extracting only a part of the excess heat above equilibrium conditions to obtain target optimum waste temperatures for maximum gas generation. Heat regulation allows for controlling the waste temperatures to achieve uniform distribution at target levels at a landfill facility. Two approaches are provided for the regulation strategy: redistributing the excess heat across a landfill to obtain uniform target optimum waste temperatures for maximum gas generation and redistributing the excess heat across a landfill to obtain specific target temperatures. Heat supplementation allows for controlling heat generation using external thermal energy sources to achieve target waste temperatures. Two approaches are provided for the supplementation strategy: adding heat to the waste mass using an external energy source to increase waste temperatures and cooling the waste mass using an external energy source to decrease waste temperatures. For all strategies, available landfill heat energy is determined based on the difference between the waste temperatures and the target temperatures. Example analyses using data from landfill facilities with relatively low and high heat generation indicated thermal energy in the range of -48.4 to 72.4MJ/m(3) available for heat management. Further modeling and experimental analyses are needed to verify the effectiveness

  18. Mitigation of methane emission from an old unlined landfill in Klintholm, Denmark using a passive biocover system

    SciTech Connect

    Scheutz, Charlotte; Pedersen, Rasmus Broe; Petersen, Per Haugsted; Samuelsson, Jerker

    2014-07-15

    Highlights: • An innovative biocover system was constructed on a landfill cell to mitigate the methane emission. • The biocover system had a mitigation efficiently of typically 80%. • The system also worked efficiently at ambient temperatures below freezing. • A whole landfill emission measurement tool was required to document the biocover system efficiency. - Abstract: Methane generated at landfills contributes to global warming and can be mitigated by biocover systems relying on microbial methane oxidation. As part of a closure plan for an old unlined landfill without any gas management measures, an innovative biocover system was established. The system was designed based on a conceptual model of the gas emission patterns established through an initial baseline study. The study included construction of gas collection trenches along the slopes of the landfill where the majority of the methane emissions occurred. Local compost materials were tested as to their usefulness as bioactive methane oxidizing material and a suitable compost mixture was selected. Whole site methane emission quantifications based on combined tracer release and downwind measurements in combination with several local experimental activities (gas composition within biocover layers, flux chamber based emission measurements and logging of compost temperatures) proved that the biocover system had an average mitigation efficiency of approximately 80%. The study showed that the system also had a high efficiency during winter periods with temperatures below freezing. An economic analysis indicated that the mitigation costs of the biocover system were competitive to other existing greenhouse gas mitigation options.

  19. Stable isotope signatures for characterising the biological stability of landfilled municipal solid waste.

    PubMed

    Wimmer, Bernhard; Hrad, Marlies; Huber-Humer, Marion; Watzinger, Andrea; Wyhlidal, Stefan; Reichenauer, Thomas G

    2013-10-01

    Stable isotopic signatures of landfill leachates are influenced by processes within municipal solid waste (MSW) landfills mainly depending on the aerobic/anaerobic phase of the landfill. We investigated the isotopic signatures of δ(13)C, δ(2)H and δ(18)O of different leachates from lab-scale experiments, lysimeter experiments and a landfill under in situ aeration. In the laboratory, columns filled with MSW of different age and reactivity were percolated under aerobic and anaerobic conditions. In landfill simulation reactors, waste of a 25year old landfill was kept under aerobic and anaerobic conditions. The lysimeter facility was filled with mechanically shredded fresh waste. After starting of the methane production the waste in the lysimeter containments was aerated in situ. Leachate and gas composition were monitored continuously. In addition the seepage water of an old landfill was collected and analysed periodically before and during an in situ aeration. We found significant differences in the δ(13)C-value of the dissolved inorganic carbon (δ(13)C-DIC) of the leachate between aerobic and anaerobic waste material. During aerobic degradation, the signature of δ(13)C-DIC was mainly dependent on the isotopic composition of the organic matter in the waste, resulting in a δ(13)C-DIC of -20‰ to -25‰. The production of methane under anaerobic conditions caused an increase in δ(13)C-DIC up to values of +10‰ and higher depending on the actual reactivity of the MSW. During aeration of a landfill the aerobic degradation of the remaining organic matter caused a decrease to a δ(13)C-DIC of about -20‰. Therefore carbon isotope analysis in leachates and groundwater can be used for tracing the oxidation-reduction status of MSW landfills. Our results indicate that monitoring of stable isotopic signatures of landfill leachates over a longer time period (e.g. during in situ aeration) is a powerful and cost-effective tool for characterising the biodegradability and

  20. Yolo County's Accelerated Anaerobic and Aerobic Composting (Full-Scale Controlled Landfill Bioreactor) Project

    NASA Astrophysics Data System (ADS)

    Yazdani, R.; Kieffer, J.; Akau, H.; Augenstein, D.

    2002-12-01

    elimination of methane production and acceleration of waste decomposition. In the first phase of this project a 12-acre module that contains a 9.5-acre anaerobic cell and a 2.5-acre aerobic cell has been constructed and filled with over 220,000 tons of municipal solid waste. Water and leachate addition began in April 2002 and to date less than 200,000 gallons of liquid has been added to the 3.5-acre anaerobic cell. The waste filling phase of the aerobic cell was completed in June of 2002 and a 12-inches soil cover and 12-inches of greenwaste compost cover was placed on top of the cell. A vacuum will be applied to the piping within the waste to draw air through the landfill. Instrumentations have been installed to monitor the following parameters: waste temperature, moisture, leachate volumes, leachate hydraulic head over the primary liner, leachate composition, gas volumes and composition. A supervisory Control and Data Acquisition (SCADA) system has been installed to monitor and control the operation of the bioreactor cells. Waste samples were taken from each cell for laboratory testing in early June 2002.

  1. Gas composition sensing using carbon nanotube arrays

    NASA Technical Reports Server (NTRS)

    Li, Jing (Inventor); Meyyappan, Meyya (Inventor)

    2008-01-01

    A method and system for estimating one, two or more unknown components in a gas. A first array of spaced apart carbon nanotubes (''CNTs'') is connected to a variable pulse voltage source at a first end of at least one of the CNTs. A second end of the at least one CNT is provided with a relatively sharp tip and is located at a distance within a selected range of a constant voltage plate. A sequence of voltage pulses {V(t.sub.n)}.sub.n at times t=t.sub.n (n=1, . . . , N1; N1.gtoreq.3) is applied to the at least one CNT, and a pulse discharge breakdown threshold voltage is estimated for one or more gas components, from an analysis of a curve I(t.sub.n) for current or a curve e(t.sub.n) for electric charge transported from the at least one CNT to the constant voltage plate. Each estimated pulse discharge breakdown threshold voltage is compared with known threshold voltages for candidate gas components to estimate whether at least one candidate gas component is present in the gas. The procedure can be repeated at higher pulse voltages to estimate a pulse discharge breakdown threshold voltage for a second component present in the gas.

  2. The environmental comparison of landfilling vs. incineration of MSW accounting for waste diversion

    SciTech Connect

    Assamoi, Bernadette; Lawryshyn, Yuri

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer Residential waste diversion initiatives are more successful with organic waste. Black-Right-Pointing-Pointer Using a incineration to manage part of the waste is better environmentally. Black-Right-Pointing-Pointer Incineration leads to more power plant emission offsets. Black-Right-Pointing-Pointer Landfilling all of the waste would be preferred financially. - Abstract: This study evaluates the environmental performance and discounted costs of the incineration and landfilling of municipal solid waste that is ready for the final disposal while accounting for existing waste diversion initiatives, using the life cycle assessment (LCA) methodology. Parameters such as changing waste generation quantities, diversion rates and waste composition were also considered. Two scenarios were assessed in this study on how to treat the waste that remains after diversion. The first scenario is the status quo, where the entire residual waste was landfilled whereas in the second scenario approximately 50% of the residual waste was incinerated while the remainder is landfilled. Electricity was produced in each scenario. Data from the City of Toronto was used to undertake this study. Results showed that the waste diversion initiatives were more effective in reducing the organic portion of the waste, in turn, reducing the net electricity production of the landfill while increasing the net electricity production of the incinerator. Therefore, the scenario that incorporated incineration performed better environmentally and contributed overall to a significant reduction in greenhouse gas emissions because of the displacement of power plant emissions; however, at a noticeably higher cost. Although landfilling proves to be the better financial option, it is for the shorter term. The landfill option would require the need of a replacement landfill much sooner. The financial and environmental effects of this expenditure have yet to be considered.

  3. COMPOSITION OF LOW-REDSHIFT HALO GAS

    SciTech Connect

    Cen Renyue

    2013-06-20

    Halo gas in low-z (z < 0.5) {>=}0.1 L{sub *} galaxies in high-resolution, large-scale cosmological hydrodynamic simulations is examined with respect to three components: cold, warm, and hot with temperatures of <10{sup 5}, 10{sup 5-6}, and >10{sup 6} K, respectively. Utilizing O VI {lambda}{lambda}1032, 1038 absorption lines, the warm component is compared to observations, and agreement is found with respect to the galaxy-O VI line correlation, the ratio of the O VI line incidence rate in blue to red galaxies, and the amount of O VI mass in star-forming galaxies. A detailed account of the sources of warm halo gas (stellar feedback heating, gravitational shock heating, and accretion from the intergalactic medium), inflowing and outflowing warm halo gas metallicity disparities, and their dependencies on galaxy types and environment is also presented. With the warm component securely anchored, our simulations make the following additional predictions. First, cold gas is the primary component in inner regions with its mass comprising 50% of all gas within galactocentric radius r = (30, 150) kpc in (red, blue) galaxies. Second, at r > (30, 200) kpc in (red, blue) galaxies the hot component becomes the majority. Third, the warm component is a perpetual minority, with its contribution peaking at {approx}30% at r = 100-300 kpc in blue galaxies and never exceeding 5% in red galaxies. The significant amount of cold gas in low-z early-type galaxies, which was found in simulations and in agreement with recent observations (Thom et al.), is intriguing, as is the dominance of hot gas at large radii in blue galaxies.

  4. Determination of nonylphenol isomers in landfill leachate and municipal wastewater using steam distillation extraction coupled with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry

    USGS Publications Warehouse

    Zhang, Caixiang; Eganhouse, Robert P.; Pontolillo, James; Cozzarelli, Isabelle M.; Wang, Yanxin

    2012-01-01

    4-Nonylphenols (4-NPs) are known endocrine disruptors and by-products of the microbial degradation of nonylphenol polyethoxylate surfactants. One of the challenges to understanding the toxic effects of nonylphenols is the large number of isomers that may exist in environmental samples. In order to attribute toxic effects to specific compounds, a method is needed for the separation and quantitation of individual nonylphenol isomers. The pre-concentration methods of solvent sublimation, solid-phase extraction or liquid–liquid extraction prior to chromatographic analysis can be problematic because of co-extraction of thousands of compounds typically found in complex matrices such as municipal wastewater or landfill leachate. In the present study, steam distillation extraction (SDE) was found to be an effective pre-concentration method for extraction of 4-NPs from leachate and wastewater, and comprehensive two-dimensional gas chromatography (GC × GC) coupled with fast mass spectral data acquisition by time-of-flight mass spectrometry (ToFMS) enhanced the resolution and identification of 4-NP isomers. Concentrations of eight 4-NP isomers were determined in leachate from landfill cells of different age and wastewater influent and effluent samples. 4-NP isomers were about 3 times more abundant in leachate from the younger cell than the older one, whereas concentrations in wastewater effluent were either below detection limits or <1% of influent concentrations. 4-NP isomer distribution patterns were found to have been altered following release to the environment. This is believed to reflect isomer-specific degradation and accumulation of 4-NPs in the aquatic environment.

  5. Determination of nonylphenol isomers in landfill leachate and municipal wastewater using steam distillation extraction coupled with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry.

    PubMed

    Zhang, Caixiang; Eganhouse, Robert P; Pontolillo, James; Cozzarelli, Isabelle M; Wang, Yanxin

    2012-03-23

    4-Nonylphenols (4-NPs) are known endocrine disruptors and by-products of the microbial degradation of nonylphenol polyethoxylate surfactants. One of the challenges to understanding the toxic effects of nonylphenols is the large number of isomers that may exist in environmental samples. In order to attribute toxic effects to specific compounds, a method is needed for the separation and quantitation of individual nonylphenol isomers. The pre-concentration methods of solvent sublimation, solid-phase extraction or liquid-liquid extraction prior to chromatographic analysis can be problematic because of co-extraction of thousands of compounds typically found in complex matrices such as municipal wastewater or landfill leachate. In the present study, steam distillation extraction (SDE) was found to be an effective pre-concentration method for extraction of 4-NPs from leachate and wastewater, and comprehensive two-dimensional gas chromatography (GC×GC) coupled with fast mass spectral data acquisition by time-of-flight mass spectrometry (ToFMS) enhanced the resolution and identification of 4-NP isomers. Concentrations of eight 4-NP isomers were determined in leachate from landfill cells of different age and wastewater influent and effluent samples. 4-NP isomers were about 3 times more abundant in leachate from the younger cell than the older one, whereas concentrations in wastewater effluent were either below detection limits or <1% of influent concentrations. 4-NP isomer distribution patterns were found to have been altered following release to the environment. This is believed to reflect isomer-specific degradation and accumulation of 4-NPs in the aquatic environment.

  6. Improving the gas-chromatographic determination of the composition of the gas liberated from a battery

    SciTech Connect

    Dmitriev, V.V.; Zubov, M.S.; Baulov, V.I.; Toguzov, B.M.

    1992-07-10

    Normally, gas chromatography is used for analyzing the gas composition that is liberated when batteries operate. Earlier work describes a gas-chromatographic technique for determining the composition of gas liberated from a battery. According to this reference, the gas is collected in an inverted burette over water. The gas is either sampled with a batching valve or with a medical syringe, which pierces the connecting vacuum hoses. The gas sample is injected into the chromatographic evaporator, and is separated on the chromatographic column into its individual components, each of which is analyzed on the detector. The method described was used to study gas liberation during the storage of charged nickel-zinc batteries. In the method described above, a high proportion of the gas specimen that accumulates and is collected in the measuring system occurs in the dead space volume. In this situation, it is very difficult to determine the liberated gas composition with a high degree of accuracy when the gas is liberated at low rates. Moreover, this method does not provide reliable system air tightness during long term operation of the batteries. 5 refs., 2 figs., 1 tab.

  7. Emissions of organo-metal compounds via the leachate and gas pathway from two differently pre-treated municipal waste materials - A landfill reactor study

    SciTech Connect

    Michalzik, B. Ilgen, G.; Hertel, F.; Hantsch, S.; Bilitewski, B.

    2007-07-01

    Due to their broad industrial production and use as PVC-stabilisers, agro-chemicals and anti-fouling agents, organo-metal compounds are widely distributed throughout the terrestrial and marine biogeosphere. Here, we focused on the emission dynamics of various organo-metal compounds (e.g., di,- tri-, tetra-methyl tin, di-methyl mercury, tetra-methyl lead) from two different kinds of pre-treated mass waste, namely mechanically-biologically pre-treated municipal solid waste (MBP MSW) and municipal waste incineration ash (MWIA). In landfill simulation reactors, the emission of the organo-metal compounds via the leachate and gas pathway was observed over a period of 5 months simulating different environmental conditions (anaerobic with underlying soil layer/aerated/anaerobic). Both waste materials differ significantly in their initial amounts of organo-metal compounds and their environmental behaviour with regard to the accumulation and depletion rates within the solid material during incubation. For tri-methyl tin, the highest release rates in leachates were found in the incineration ash treatments, where anaerobic conditions in combination with underlying soil material significantly promoted its formation. Concerning the gas pathway, anaerobic conditions considerably favour the emission of organo-metal compounds (tetra-methyl tin, di-methyl mercury, tetra-methyl lead) in both the MBP material and especially in the incineration ash.

  8. LANDFILL GAS CONVERSION TO LNG AND LCO{sub 2}. PHASE 1, FINAL REPORT FOR THE PERIOD MARCH 1998-FEBRUARY 1999

    SciTech Connect

    COOK,W.J.; NEYMAN,M.; SIWAJEK,L.A.; BROWN,W.R.; VAN HAUWAERT,P.M.; CURREN,E.D.

    1998-02-25

    Process designs and economics were developed to produce LNG and liquid carbon dioxide (CO{sub 2}) from landfill gas (LFG) using the Acrion CO{sub 2} wash process. The patented Acrion CO{sub 2} wash process uses liquid CO{sub 2} to absorb contaminants from the LFG. The process steps are compression, drying, CO{sub 2} wash contaminant removal and CO{sub 2} recovery, residual CO{sub 2} removal and methane liquefaction. Three flowsheets were developed using different residual CO{sub 2} removal schemes. These included physical solvent absorption (methanol), membranes and molecular sieves. The capital and operating costs of the flowsheets were very similar. The LNG production cost was around ten cents per gallon. In parallel with process flowsheet development, the business aspects of an eventual commercial project have been explored. The process was found to have significant potential commercial application. The business plan effort investigated the economics of LNG transportation, fueling, vehicle conversion, and markets. The commercial value of liquid CO{sub 2} was also investigated. This Phase 1 work, March 1998 through February 1999, was funded under Brookhaven National laboratory contract 725089 under the research program entitled ``Liquefied Natural Gas as a Heavy Vehicle Fuel.'' The Phase 2 effort will develop flowsheets for the following: (1) CO{sub 2} and pipeline gas production, with the pipeline methane being liquefied at a peak shaving site, (2) sewage digester gas as an alternate feedstock to LFG and (3) the use of mixed refrigerants for process cooling. Phase 2 will also study the modification of Acrion's process demonstration unit for the production of LNG and a market site for LNG production.

  9. Early rhizosphere microbiome composition is related to the growth and Zn uptake of willows introduced to a former landfill.

    PubMed

    Bell, Terrence H; Cloutier-Hurteau, Benoît; Al-Otaibi, Fahad; Turmel, Marie-Claude; Yergeau, Etienne; Courchesne, François; St-Arnaud, Marc

    2015-08-01

    Although plants introduced for site restoration are pre-selected for specific traits (e.g. trace element bioaccumulation, rapid growth in poor soils), the in situ success of these plants likely depends on the recruitment of appropriate rhizosphere microorganisms from their new environment. We introduced three willow (Salix spp.) cultivars to a contaminated landfill, and performed soil chemical analyses, plant measurements, and Ion Torrent sequencing of rhizospheric fungal and bacterial communities at 4 and 16 months post-planting. The abundance of certain dominant fungi was linked to willow accumulation of Zn, the most abundant trace element at the site. Interestingly, total Zn accumulation was better explained by fungal community structure 4 months post-planting than 16 months post-planting, suggesting that initial microbial recruitment may be critical. In addition, when the putative ectomycorrhizal fungi Sphaerosporella brunnea and Inocybe sp. dominated the rhizosphere 4 months post-planting, Zn accumulation efficiency was negatively correlated with fungal diversity. Although field studies such as this rely on correlation, these results suggest that the soil microbiome may have the greatest impact on plant function during the early stages of growth, and that plant-fungus specificity may be essential.

  10. Quantification of parameters influencing methane generation due to biodegradation of municipal solid waste in landfills and laboratory experiments.

    PubMed

    Fei, Xunchang; Zekkos, Dimitrios; Raskin, Lutgarde

    2016-09-01

    The energy conversion potential of municipal solid waste (MSW) disposed of in landfills remains largely untapped because of the slow and variable rate of biogas generation, delayed and inefficient biogas collection, leakage of biogas, and landfill practices and infrastructure that are not geared toward energy recovery. A database consisting of methane (CH4) generation data, the major constituent of biogas, from 49 laboratory experiments and field monitoring data from 57 landfills was developed. Three CH4 generation parameters, i.e., waste decay rate (k), CH4 generation potential (L0), and time until maximum CH4 generation rate (tmax), were calculated for each dataset using U.S. EPA's Landfill Gas Emission Model (LandGEM). Factors influencing the derived parameters in laboratory experiments and landfills were investigated using multi-linear regression analysis. Total weight of waste (W) was correlated with biodegradation conditions through a ranked classification scheme. k increased with increasing percentage of readily biodegradable waste (Br0 (%)) and waste temperature, and reduced with increasing W, an indicator of less favorable biodegradation conditions. The values of k obtained in the laboratory were commonly significantly higher than those in landfills and those recommended by LandGEM. The mean value of L0 was 98 and 88L CH4/kg waste for laboratory and field studies, respectively, but was significantly affected by waste composition with ranges from 10 to 300L CH4/kg. tmax increased with increasing percentage of biodegradable waste (B0) and W. The values of tmax in landfills were higher than those in laboratory experiments or those based on LandGEM's recommended parameters. Enhancing biodegradation conditions in landfill cells has a greater impact on improving k and tmax than increasing B0. Optimizing the B0 and Br0 values of landfilled waste increases L0 and reduces tmax.

  11. Landfill aeration for emission control before and during landfill mining.

    PubMed

    Raga, Roberto; Cossu, Raffaello; Heerenklage, Joern; Pivato, Alberto; Ritzkowski, Marco

    2015-12-01

    The landfill of Modena, in northern Italy, is now crossed by the new high velocity railway line connecting Milan and Bologna. Waste was completely removed from a part of the landfill and a trench for the train line was built. With the aim of facilitating excavation and further disposal of the material extracted, suitable measures were defined. In order to prevent undesired emissions into the excavation area, the aerobic in situ stabilisation by means of the Airflow technology took place before and during the Landfill Mining. Specific project features involved the pneumatic leachate extraction from the aeration wells (to keep the leachate table low inside the landfill and increase the volume of waste available for air migration) and the controlled moisture addition into a limited zone, for a preliminary evaluation of the effects on process enhancement. Waste and leachate were periodically sampled in the landfill during the aeration before the excavation, for quality assessment over time; the evolution of biogas composition in the landfill body and in the extraction system for different plant set-ups during the project was monitored, with specific focus on uncontrolled migration into the excavation area. Waste biological stability significantly increased during the aeration (waste respiration index dropped to 33% of the initial value after six months). Leachate head decreased from 4 to 1.5m; leachate recirculation tests proved the beneficial effects of moisture addition on temperature control, without hampering waste aerobization. Proper management of the aeration plant enabled the minimization of uncontrolled biogas emissions into the excavation area. PMID:26445364

  12. Carbon-fiber composite molecular sieves for gas separation

    SciTech Connect

    Jagtoyen, M.; Derbyshire, F.; Kimber, G.; Fei, Y.Q.

    1995-08-01

    The progress of research in the development of novel, rigid, monolithic adsorbent carbon fiber composites is described. Carbon fiber composites are produced at ORNL and activated at the CAER using steam or CO{sub 2} under different conditions, with the aims of producing a uniform degree of activation through the material, and of closely controlling pore structure and adsorptive properties The principal focus of the work to date has been to produce materials with narrow porosity for use in gas separations.

  13. Degradability of Chlorinated Solvents in Landfill Environment

    NASA Astrophysics Data System (ADS)

    Wang, J. Y.; Litman, M.

    2002-12-01

    The use of landfills as an in situ remediation system represents a cost-effective alternative for groundwater remediation in the source area. This research was conducted to investigate the intrinsic bioattenuation capacity of the landfill ecosystem for chlorinated aliphatic hydrocarbons (CAHs). This research, using excavated refuse samples, studied how the reductive dechlorination of CAHs is linked to the decomposition of solid waste in landfills. Most research effort in groundwater remediation has focused on the contaminant plumes beneath and downgradient from landfills, while the source area remediation has received increasing attention. Bioreactor landfill and leachate recirculation projects have been planned and implemented by the USEPA and some states. However, the use of bioreactor landfill has primarily been considered only to expedite refuse decomposition. This research provides an understanding of the biological fate of CAHs in landfills, an understanding that can lead to the bioreactor landfill system designed to promote the degradation of pollutants right at the source. The research was conducted in two complementary systems: simulated landfill bioreactors and batch degradation experiment in serum bottles. Refuse samples were excavated from a municipal solid waste landfill located in Wayland, Massachusetts, USA. Bioreactors were designed and operated to facilitate refuse decomposition under landfilling conditions. For each reactor, leachate was collected and recirculated back to the reactor and gas was collected into a gas bag and the methane production rate was monitored. Target CAHs, tetrachloroethene (PCE) and trichloroethene (TCE), were added to selected reactors and maintained at about 20 uM each in leachate. The design is to study the effect of long-term exposure of refuse microorganisms to CAHs on the degradation potential of these chemicals in landfills. Changes of biochemical conditions in bioreactors, including leachate pH, leachate COD, and

  14. Hydrological and geochemical factors affecting leachate composition in municipal solid waste incinerator bottom ash. Part I: The hydrology of Landfill Lostorf, Switzerland

    NASA Astrophysics Data System (ADS)

    Johnson, C. Annette; Richner, Gérald A.; Vitvar, Tomas; Schittli, Nina; Eberhard, Mark

    1998-10-01

    The objective of the investigation of the municipal solid waste incinerator (MSWI) bottom ash landfill, Landfill Lostorf, was to determine the residence time of water in the landfill and the flow paths through the landfill. Over a period of 22 months, measurements of rainfall, landfill discharge and leachate electrical conductivity were recorded and tracer experiments made. Over the yearly period 1995, approximately 50% of the incident rainfall was measured in the discharge. An analysis of single rain events showed that in winter, 90-100% of rainfall was expressed in the landfill discharge, whereas in summer months, the value was between 9 and 40% depending on the intensity of the rain event. The response to rainfall was rapid. Within 30-100 h, approximately 50% of water discharged in response to a rain event had left the landfill. The discharge was less than 4 l/min for approximately 50% of the measurement periods. Qualitative tracer studies with fluorescein, pyranine and iodide clearly showed the existence of preferential flow paths. This was further substantiated by quantitative tracer studies of single rain events using 18O/ 16O ratios and electrical conductivity measurements. The proportion of rainwater passing directly through the landfill was found to be between 20 and 80% in summer months and around 10% in winter months. The difference has been ascribed to the water content in the landfill. The average residence time of the water within the landfill has been estimated to be roughly 3 years and this water is the predominant component in the discharge over a yearly period.

  15. Learning from Landfills.

    ERIC Educational Resources Information Center

    Galus, Pamela

    2000-01-01

    Describes a project in which students developed an all-class laboratory activity called "The Decomposition of Organic and Inorganic Substances in a Landfill". Explores what conditions are necessary to facilitate decomposition in a landfill. (SAH)

  16. Tunable Composite Membranes for Gas Separations.

    SciTech Connect

    Ferraris, J.P.; Balkus, K.J. Jr.; Musselman, I.H.

    1997-10-01

    Poly(3-dodecylthiophene) films were solution cast and subsequently subjected to chemical oxidation (doping), followed by chemical undoping. The microstructure of each form of the membrane was determined by optical microscopy (OM), scanning electron microscopy (SEM) and TappingMode Atomic Force Microscopy (TMAFM). Energy dispersive x-ray spectrometry (EDS) was used to elucidate the chemical composition of the membranes. Changes in microstructure after exposure to or protection from the laboratory atmosphere, and after permeability measurements, were assessed by these same techniques to estimate the environmental stability of the membranes. Although dramatic changes in topology occur for films exposed to the laboratory atmosphere, these are greatly reduced when the films are stored in containers that limit the access of moisture. Films exposed to dry gases in the permeameter exhibit essentially no change to their original microstructures.

  17. Modelling of environmental impacts of solid waste landfilling within the life-cycle analysis program EASEWASTE

    SciTech Connect

    Kirkeby, Janus T.; Birgisdottir, Harpa; Bhander, Gurbakash Singh; Hauschild, Michael; Christensen, Thomas H.

    2007-07-01

    A new computer-based life-cycle assessment model (EASEWASTE) has been developed to evaluate resource and environmental consequences of solid waste management systems. This paper describes the landfilling sub-model used in the life-cycle assessment program EASEWASTE, and examines some of the implications of this sub-model. All quantities and concentrations of leachate and landfill gas can be modified by the user in order to bring them in agreement with the actual landfill that is assessed by the model. All emissions, except the generation of landfill gas, are process specific. The landfill gas generation is calculated on the basis of organic matter in the landfilled waste. A landfill assessment example is provided. For this example, the normalised environmental effects of landfill gas on global warming and photochemical smog are much greater than the environmental effects for landfill leachate or for landfill construction. A sensitivity analysis for this example indicates that the overall environmental impact is sensitive to the gas collection efficiency and the use of the gas, but not to the amount of leachate generated, or the amount of soil or liner material used in construction. The landfill model can be used for evaluating different technologies with different liners, gas and leachate collection efficiencies, and to compare the environmental consequences of landfilling with alternative waste treatment options such as incineration or anaerobic digestion.

  18. Effects of shielding gas compositions on arc plasma and metal transfer in gas metal arc welding

    SciTech Connect

    Rao, Z. H.; Liao, S. M.; Tsai, H. L.

    2010-02-15

    This article presents the effects of shielding gas compositions on the transient transport phenomena, including the distributions of temperature, flow velocity, current density, and electromagnetic force in the arc and the metal, and arc pressure in gas metal arc welding of mild steel at a constant current input. The shielding gas considered includes pure argon, 75% Ar, 50% Ar, and 25% Ar with the balance of helium. It is found that the shielding gas composition has significant influences on the arc characteristics; droplet formation, detachment, transfer, and impingement onto the workpiece; and weld pool dynamics and weld bead profile. As helium increases in the shielding gas, the droplet size increases but the droplet detachment frequency decreases. For helium-rich gases, the current converges at the workpiece with a 'ring' shape which produces non-Gaussian-like distributions of arc pressure and temperature along the workpiece surface. Detailed explanations to the physics of the very complex but interesting transport phenomena are given.

  19. The carbon isotopic composition of catalytic gas: A comparative analysis with natural gas

    SciTech Connect

    Mango, F.D.; Elrod, L.W.

    1999-04-01

    Tee idea that natural gas is the thermal product of organic decomposition has persisted for over half a century. Crude oil is thought to be an important source of gas, cracking to wet gas above 150 C, and dry gas above 200 C. But there is little evidence to support this view. For example, crude oil is proving to be more stable than previously thought and projected to remain intact over geologic time at typical reservoir temperature. Moreover, when oil does crack, the products do not resemble natural gas. Oil to gas could be catalytic, however, promoted by the transition metals in carbonaceous sediments. This would explain the low temperatures at which natural gas forms, and the high amounts of methane. This idea gained support recently when the natural progression of oil to dry gas was duplicated in the laboratory catalytically. The authors report here the isotopic composition of catalytic gas generated from crude oil and pure hydrocarbons between 150 and 200 C. {delta}{sup 13}C for C{sub 1} through C{sub 5} was linear with 1/n (n = carbon number) in accordance with theory and typically seen in natural gases. Over extended reaction, isobutane and isopentane remained lighter than their respective normal isomers and the isotopic differentials were constant as all isomers became heavier over time. Catalytic methane, initially {minus}51.87{per_thousand} (oil = {minus}22.5{per_thousand}), progressed to a final composition of {minus}26.94{per_thousand}, similar to the maturity trend seen in natural gases: {minus}50{per_thousand} to {minus}20{per_thousand}. Catalytic gas is thus identical to natural gas in molecular and isotopic composition adding further support to the view that catalysis by transition metals may be a significant source of natural gas.

  20. Development of an empirical model of methane emissions from landfills. Final report Mar-Dec 91

    SciTech Connect

    Peer, R.L.; Epperson, D.L.; Campbell, D.L.; von Brook, P.

    1992-03-01

    The report gives results of a field study of 21 U.S. landfills with gas recovery systems, to gather information that can be used to develop an empirical model of methane (CH4) emissions. Site-specific information includes average CH4 recovery rate, landfill size, tons of refuse (refuse mass), average age of the refuse, and climate. A correlation analysis showed that refuse mass was positively linearly correlated with landfill depth, volume, area, and well depth. Regression of the CH4 recovery rate on depth, refuse mass, and volume was significant, but depth was the best predictive variable (R2 = 0.53). Refuse mass was nearly as good (R2 = 0.50). None of the climate variables (precipitation, average temperature, dewpoint) were correlated with the CH4 recovery rate or with CH4 recovery per metric ton of refuse. Much of the variability in CH4 recovery remains unexplained, and is likely due to between-site differences in landfill construction, operation, and refuse composition. A model for global landfill emissions estimation is proposed.

  1. Generating CO(2)-credits through landfill in situ aeration.

    PubMed

    Ritzkowski, M; Stegmann, R

    2010-04-01

    Landfills are some of the major anthropogenic sources of methane emissions worldwide. The installation and operation of gas extraction systems for many landfills in Europe and the US, often including technical installations for energy recovery, significantly reduced these emissions during the last decades. Residual landfill gas, however, is still continuously produced after the energy recovery became economically unattractive, thus resulting in ongoing methane emissions for many years. By landfill in situ aeration these methane emissions can be widely avoided both, during the aeration process as well as in the subsequent aftercare period. Based on model calculations and online monitoring data the amount of avoided CO(2-eq). can be determined. For an in situ aerated landfill in northern Germany, acting as a case study, 83-95% (depending on the kind and quality of top cover) of the greenhouse gas emission potential could be reduced under strictly controlled conditions. Recently the United Nations Framework Convention on Climate Change (UNFCCC) has approved a new methodology on the "Avoidance of landfill gas emissions by in situ aeration of landfills" (UNFCCC, 2009). Based on this methodology landfill aeration projects might be considered for generation of Certified Emission Reductions (CERs) in the course of CDM projects. This paper contributes towards an evaluation of the potential of landfill aeration for methane emissions reduction.

  2. Internal friction and gas desorption of {C}/{C} composites

    NASA Astrophysics Data System (ADS)

    Serizawa, H.; Sato, S.; Kohyama, A.

    1994-09-01

    {C}/{C} composites are the most promising candidates as high heat flux component materials, where temperature dependence of mechanical properties and gas desorption behavior at elevated temperature are important properties. At the beginning, the newly developed internal friction measurement apparatus, which enables the accurate measurement of dynamic elastic properties up to 1373 K along with the measurement of gas desorption behavior, was used. The materials studied were unidirectional (UD) {C}/{C} composites reinforced with mesophase pitch-based carbon fibers, which were heat treated at temperatures ranging from 1473 to 2773 K which produced a variety of graphitized microstructures. Two-dimensional (2D) {C}/{C} composites reinfored with flat woven fabrics of PAN type carbon fibers were also studied. These materials were heat treated at 1873 K. From the temperature spectrum of internal friction of 2D {C}/{C} composites, these internal friction peaks were detected and were related to gas desorption. Also the temperature dependence of Young's modulus of UD {C}/{C} composites, negative and positive dependence of Young's modulus were observed reflecting microstructure changes resulting from the heat treatments.

  3. Geothermal gas compositions in yellowstone National Park, USA

    USGS Publications Warehouse

    Sheppard, D.S.; Truesdell, A.H.; Janik, C.J.

    1992-01-01

    Gas samples collected between 1974 and 1986 have been analysed for the ten major components. Samples have been collected almost exclusively from the tops of pools, which has degraded the value of the data, and limited inter-comparisons to the relatively insoluble components, Ar, N2, CH4, H2 and He. A general gas distribution pattern in the park, in terms of these components, shows the major heat source(s) to underlie the Gibbon and Mud Volcano areas with all other geothermal areas having gas compositions consistent with a general north-south water flow. Shoshone Basin gases show a large range of compositions and these are analysed in detail. The patterns conform to that which would be expected from an east-west flow or fluid with progressive boiling and subsequent dilution. ?? 1992.

  4. Geothermal gas compositions in yellowstone National Park, USA

    NASA Astrophysics Data System (ADS)

    Sheppard, D. S.; Truesdell, A. H.; Janik, C. J.

    1992-06-01

    Gas samples collected between 1974 and 1986 have been analysed for the ten major components. Samples have been collected almost exclusively from the tops of pools, which has degraded the value of the data, and limited inter-comparisons to the relatively insoluble components, Ar, N 2, CH 4, H 2 and He. A general gas distribution pattern in the park, in terms of these components, shows the major heat source(s) to underlie the Gibbon and Mud Volcano areas with all other geothermal areas having gas compositions consistent with a general north-south water flow. Shoshone Basin gases show a large range of compositions and these are analysed in detail. The patterns conform to that which would be expected from an east-west flow or fluid with progressive boiling and subsequent dilution.

  5. Quantification of methane emissions from 15 Danish landfills using the mobile tracer dispersion method

    SciTech Connect

    Mønster, Jacob; Samuelsson, Jerker; Scheutz, Charlotte

    2015-01-15

    Highlights: • Quantification of whole landfill site methane emission at 15 landfills. • Multiple on-site source identification and quantification. • Quantified methane emission from shredder waste and composting. • Large difference between measured and reported methane emissions. - Abstract: Whole-site methane emissions from 15 Danish landfills were assessed using a mobile tracer dispersion method with either Fourier transform infrared spectroscopy (FTIR), using nitrous oxide as a tracer gas, or cavity ring-down spectrometry (CRDS), using acetylene as a tracer gas. The landfills were chosen to represent the different stages of the lifetime of a landfill, including open, active, and closed covered landfills, as well as those with and without gas extraction for utilisation or flaring. Measurements also included landfills with biocover for oxidizing any fugitive methane. Methane emission rates ranged from 2.6 to 60.8 kg h{sup −1}, corresponding to 0.7–13.2 g m{sup −2} d{sup −1}, with the largest emission rates per area coming from landfills with malfunctioning gas extraction systems installed, and the smallest emission rates from landfills closed decades ago and landfills with an engineered biocover installed. Landfills with gas collection and recovery systems had a recovery efficiency of 41–81%. Landfills where shredder waste was deposited showed significant methane emissions, with the largest emission from newly deposited shredder waste. The average methane emission from the landfills was 154 tons y{sup −1}. This average was obtained from a few measurement campaigns conducted at each of the 15 landfills and extrapolating to annual emissions requires more measurements. Assuming that these landfills are representative of the average Danish landfill, the total emission from Danish landfills were calculated at 20,600 tons y{sup −1}, which is significantly lower than the 33,300 tons y{sup −1} estimated for the national greenhouse gas inventory for

  6. TUNABLE COMPOSITE MEMBRANES FOR GAS SEPARATIONS

    SciTech Connect

    J.P. Ferraris; K.J. Balkus, Jr.; I.H. Musselman

    1998-10-01

    Poly(3-octylthiophene), POT, membranes were selectively oxidized on one side using SbCl{sub 5} solutions (15, 20, and 25% w/w in CH{sub 3}CN). Oxidation with a 25% SbCl{sub 5} solution resulted in maximum decreases in permeability and increases in selectivity (P{sub N{sub 2}} = 3.1 {+-} 0.2, P{sub O{sub 2}} = 9.9 {+-} 0.1, P{sub CH{sub 4}} = 9.0 {+-} 0.1, P{sub CO{sub 2}} = 47.5 {+-} 0.3 Barrers, and {alpha}{sub O{sub 2}/N{sub 2}} = 3.2 {+-} 0.2, {alpha}{sub CO{sub 2}/N{sub 2}} = 15.3 {+-} 0.9, {alpha}{sub CO{sub 2}/CH{sub 4}} = 5.3 {+-} 0.3). Oxidation of a 30% NaY/POT composite membrane with a 17% w/w SbCl{sub 5} solution resulted in permeability values between the unmodified and oxidized POT membranes and selectivities similar to those of oxidized POT membranes (P{sub N{sub 2}} = 5.3 {+-} 0.6, P{sub O{sub 2}} = 16.7 {+-} 1.8, P{sub CH{sub 4}} = 15.3 {+-} 1.2, P{sub CO{sub 2}} = 80.1 {+-} 3.7 Barrers, {alpha}{sub O{sub 2}/N{sub 2}} = 3.2 {+-} 0.1, {alpha}{sub CO{sub 2}/N{sub 2}} = 15.2 {+-} 0.8, {alpha}{sub CO{sub 2}/CH{sub 4}} = 5.3 {+-} 0.2).

  7. Estimation of transport parameters of phenolic compounds and inorganic contaminants through composite landfill liners using one-dimensional mass transport model

    SciTech Connect

    Varank, Gamze; Demir, Ahmet; Yetilmezsoy, Kaan; Bilgili, M. Sinan; Top, Selin; Sekman, Elif

    2011-11-15

    Highlights: > We conduct 1D advection-dispersion modeling to estimate transport parameters. > We examine fourteen phenolic compounds and three inorganic contaminants. > 2-MP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,3,4,6-TeCP have the highest coefficients. > Dispersion coefficients of Cu are determined to be higher than Zn and Fe. > Transport of phenolics can be prevented by zeolite and bentonite in landfill liners. - Abstract: One-dimensional (1D) advection-dispersion transport modeling was conducted as a conceptual approach for the estimation of the transport parameters of fourteen different phenolic compounds (phenol, 2-CP, 2-MP, 3-MP, 4-MP, 2-NP, 4-NP, 2,4-DNP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,4,6-TCP, 2,3,4,6-TeCP, PCP) and three different inorganic contaminants (Cu, Zn, Fe) migrating downward through the several liner systems. Four identical pilot-scale landfill reactors (0.25 m{sup 3}) with different composite liners (R1: 0.10 + 0.10 m of compacted clay liner (CCL), L{sub e} = 0.20 m, k{sub e} = 1 x 10{sup -8} m/s, R2: 0.002-m-thick damaged high-density polyethylene (HDPE) geomembrane overlying 0.10 + 0.10 m of CCL, L{sub e} = 0.20 m, k{sub e} = 1 x 10{sup -8} m/s, R3: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick bentonite layer encapsulated between 0.10 + 0.10 m CCL, L{sub e} = 0.22 m, k{sub e} = 1 x 10{sup -8} m/s, R4: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick zeolite layer encapsulated between 0.10 + 0.10 m CCL, L{sub e} = 0.22 m, k{sub e} = 4.24 x 10{sup -7} m/s) were simultaneously run for a period of about 540 days to investigate the nature of diffusive and advective transport of the selected organic and inorganic contaminants. The results of 1D transport model showed that the highest molecular diffusion coefficients, ranging from 4.77 x 10{sup -10} to 10.67 x 10{sup -10} m{sup 2}/s, were estimated for phenol (R4), 2-MP (R1), 2,4-DNP (R2), 2,4-DCP (R1), 2,6-DCP (R2), 2,4,5-TCP (R2) and 2,3,4,6-TeCP (R1). For all reactors

  8. Landfill capping: The Croton Point Landfill experience

    SciTech Connect

    Srinivasaraghaven, R.; Gavin, J.M.; Landi, A.M.; Ritchie, M.D.

    1996-12-31

    The Croton Point Landfill Capping involved the installation of an impermeable, geosynthetic cap and the attendant geotechnical cover soils over a 113 acre hazardous waste landfill in Croton-On-Hudson, New York. The remediation process - Remedial Investigation, Feasibility Study (RI/FS) Remedial Design and Remedial Construction lasted six years. This paper sets forth some of the insights and experiences gained during that process and provides some practical recommendations. In particular, the paper evaluates the Croton Landfill experience in regard to Health and Safety; Stormwater Control; erosion and sediment control; QA/QC; leachate treatment and disposal; and wildlife control.

  9. Environmental assessment of Ammässuo Landfill (Finland) by means of LCA-modelling (EASEWASTE).

    PubMed

    Niskanen, Antti; Manfredi, Simone; Christensen, Thomas H; Anderson, Reetta

    2009-08-01

    The Old Ammässuo Landfill (Espoo, Finland) covers an area of 52 hectares and contains about 10 million tonnes of waste that was landfilled between 1987 and 2007. The majority of this waste was mixed, of which about 57% originated from households. This paper aims at describing the management of the Old Ammässuo Landfill throughout its operational lifetime (1987-2007), and at developing an environmental evaluation based on life-cycle assessment (LCA) using the EASEWASTE-model. The assessment criteria evaluate specific categories of impact, including standard impact categories, toxicity-related impact categories and an impact categorized as spoiled groundwater resources (SGR). With respect to standard and toxicity-related impact categories, the LCA results show that substantial impact potentials are estimated for global warming (GW), ozone depletion (OD), human toxicity via soil (HTs) and ecotoxicity in water chronic (ETwc). The largest impact potential was found for SGR and amounted to 57.6 person equivalent (PE) per tonne of landfilled waste. However, the SGR impact may not be viewed as a significant issue in Finland as the drinking water is mostly supplied from surface water bodies. Overall, the results demonstrate that gas management has great importance to the environmental performance of the Old Ammässuo Landfill. However, several chemicals related to gas composition (especially trace compounds) and specific emissions from on-site operations were not available or were not measured and were therefore taken from the literature. Measurement campaigns and field investigations should be undertaken in order to obtain a more robust and comprehensive dataset that can be used in the LCA-modelling, before major improvements regarding landfill management are finalized.

  10. Municipal Solid Waste Landfills Harbor Distinct Microbiomes.

    PubMed

    Stamps, Blake W; Lyles, Christopher N; Suflita, Joseph M; Masoner, Jason R; Cozzarelli, Isabelle M; Kolpin, Dana W; Stevenson, Bradley S

    2016-01-01

    Landfills are the final repository for most of the discarded material from human society and its "built environments." Microorganisms subsequently degrade this discarded material in the landfill, releasing gases (largely CH4 and CO2) and a complex mixture of soluble chemical compounds in leachate. Characterization of "landfill microbiomes" and their comparison across several landfills should allow the identification of environmental or operational properties that influence the composition of these microbiomes and potentially their biodegradation capabilities. To this end, the composition of landfill microbiomes was characterized as part of an ongoing USGS national survey studying the chemical composition of leachates from 19 non-hazardous landfills across 16 states in the continental U.S. The landfills varied in parameters such as size, waste composition, management strategy, geography, and climate zone. The diversity and composition of bacterial and archaeal populations in leachate samples were characterized by 16S rRNA gene sequence analysis, and compared against a variety of physical and chemical parameters in an attempt to identify their impact on selection. Members of the Epsilonproteobacteria, Gammaproteobacteria, Clostridia, and candidate division OP3 were the most abundant. The distribution of the observed phylogenetic diversity could best be explained by a combination of variables and was correlated most strongly with the concentrations of chloride and barium, rate of evapotranspiration, age of waste, and the number of detected household chemicals. This study illustrates how leachate microbiomes are distinct from those of other natural or built environments, and sheds light on the major selective forces responsible for this microbial diversity.

  11. Municipal solid waste landfills harbor distinct microbiomes

    USGS Publications Warehouse

    Stamps, Blake W.; Lyles, Christopher N.; Suflita, Joseph M.; Masoner, Jason R.; Cozzarelli, Isabelle M.; Kolpin, Dana W.; Stevenson, Bradley S.

    2016-01-01

    Landfills are the final repository for most of the discarded material from human society and its “built environments.” Microorganisms subsequently degrade this discarded material in the landfill, releasing gases (largely CH4 and CO2) and a complex mixture of soluble chemical compounds in leachate. Characterization of “landfill microbiomes” and their comparison across several landfills should allow the identification of environmental or operational properties that influence the composition of these microbiomes and potentially their biodegradation capabilities. To this end, the composition of landfill microbiomes was characterized as part of an ongoing USGS national survey studying the chemical composition of leachates from 19 non-hazardous landfills across 16 states in the continental U.S. The landfills varied in parameters such as size, waste composition, management strategy, geography, and climate zone. The diversity and composition of bacterial and archaeal populations in leachate samples were characterized by 16S rRNA gene sequence analysis, and compared against a variety of physical and chemical parameters in an attempt to identify their impact on selection. Members of the Epsilonproteobacteria, Gammaproteobacteria, Clostridia, and candidate division OP3 were the most abundant. The distribution of the observed phylogenetic diversity could best be explained by a combination of variables and was correlated most strongly with the concentrations of chloride and barium, rate of evapotranspiration, age of waste, and the number of detected household chemicals. This study illustrates how leachate microbiomes are distinct from those of other natural or built environments, and sheds light on the major selective forces responsible for this microbial diversity.

  12. Municipal Solid Waste Landfills Harbor Distinct Microbiomes.

    PubMed

    Stamps, Blake W; Lyles, Christopher N; Suflita, Joseph M; Masoner, Jason R; Cozzarelli, Isabelle M; Kolpin, Dana W; Stevenson, Bradley S

    2016-01-01

    Landfills are the final repository for most of the discarded material from human society and its "built environments." Microorganisms subsequently degrade this discarded material in the landfill, releasing gases (largely CH4 and CO2) and a complex mixture of soluble chemical compounds in leachate. Characterization of "landfill microbiomes" and their comparison across several landfills should allow the identification of environmental or operational properties that influence the composition of these microbiomes and potentially their biodegradation capabilities. To this end, the composition of landfill microbiomes was characterized as part of an ongoing USGS national survey studying the chemical composition of leachates from 19 non-hazardous landfills across 16 states in the continental U.S. The landfills varied in parameters such as size, waste composition, management strategy, geography, and climate zone. The diversity and composition of bacterial and archaeal populations in leachate samples were characterized by 16S rRNA gene sequence analysis, and compared against a variety of physical and chemical parameters in an attempt to identify their impact on selection. Members of the Epsilonproteobacteria, Gammaproteobacteria, Clostridia, and candidate division OP3 were the most abundant. The distribution of the observed phylogenetic diversity could best be explained by a combination of variables and was correlated most strongly with the concentrations of chloride and barium, rate of evapotranspiration, age of waste, and the number of detected household chemicals. This study illustrates how leachate microbiomes are distinct from those of other natural or built environments, and sheds light on the major selective forces responsible for this microbial diversity. PMID:27148222

  13. Municipal Solid Waste Landfills Harbor Distinct Microbiomes

    PubMed Central

    Stamps, Blake W.; Lyles, Christopher N.; Suflita, Joseph M.; Masoner, Jason R.; Cozzarelli, Isabelle M.; Kolpin, Dana W.; Stevenson, Bradley S.

    2016-01-01

    Landfills are the final repository for most of the discarded material from human society and its “built environments.” Microorganisms subsequently degrade this discarded material in the landfill, releasing gases (largely CH4 and CO2) and a complex mixture of soluble chemical compounds in leachate. Characterization of “landfill microbiomes” and their comparison across several landfills should allow the identification of environmental or operational properties that influence the composition of these microbiomes and potentially their biodegradation capabilities. To this end, the composition of landfill microbiomes was characterized as part of an ongoing USGS national survey studying the chemical composition of leachates from 19 non-hazardous landfills across 16 states in the continental U.S. The landfills varied in parameters such as size, waste composition, management strategy, geography, and climate zone. The diversity and composition of bacterial and archaeal populations in leachate samples were characterized by 16S rRNA gene sequence analysis, and compared against a variety of physical and chemical parameters in an attempt to identify their impact on selection. Members of the Epsilonproteobacteria, Gammaproteobacteria, Clostridia, and candidate division OP3 were the most abundant. The distribution of the observed phylogenetic diversity could best be explained by a combination of variables and was correlated most strongly with the concentrations of chloride and barium, rate of evapotranspiration, age of waste, and the number of detected household chemicals. This study illustrates how leachate microbiomes are distinct from those of other natural or built environments, and sheds light on the major selective forces responsible for this microbial diversity. PMID:27148222

  14. Stable isotope signatures for characterising the biological stability of landfilled municipal solid waste

    SciTech Connect

    Wimmer, Bernhard; Hrad, Marlies; Huber-Humer, Marion; Watzinger, Andrea; Wyhlidal, Stefan; Reichenauer, Thomas G.

    2013-10-15

    Highlights: ► The isotopic signature of δ{sup 13}C-DIC of leachates is linked to the reactivity of MSW. ► Isotopic signatures of leachates depend on aerobic/anaerobic conditions in landfills. ► In situ aeration of landfills can be monitored by isotope analysis in leachate. ► The isotopic analysis of leachates can be used for assessing the stability of MSW. ► δ{sup 13}C-DIC of leachates helps to define the duration of landfill aftercare. - Abstract: Stable isotopic signatures of landfill leachates are influenced by processes within municipal solid waste (MSW) landfills mainly depending on the aerobic/anaerobic phase of the landfill. We investigated the isotopic signatures of δ{sup 13}C, δ{sup 2}H and δ{sup 18}O of different leachates from lab-scale experiments, lysimeter experiments and a landfill under in situ aeration. In the laboratory, columns filled with MSW of different age and reactivity were percolated under aerobic and anaerobic conditions. In landfill simulation reactors, waste of a 25 year old landfill was kept under aerobic and anaerobic conditions. The lysimeter facility was filled with mechanically shredded fresh waste. After starting of the methane production the waste in the lysimeter containments was aerated in situ. Leachate and gas composition were monitored continuously. In addition the seepage water of an old landfill was collected and analysed periodically before and during an in situ aeration. We found significant differences in the δ{sup 13}C-value of the dissolved inorganic carbon (δ{sup 13}C-DIC) of the leachate between aerobic and anaerobic waste material. During aerobic degradation, the signature of δ{sup 13}C-DIC was mainly dependent on the isotopic composition of the organic matter in the waste, resulting in a δ{sup 13}C-DIC of −20‰ to −25‰. The production of methane under anaerobic conditions caused an increase in δ{sup 13}C-DIC up to values of +10‰ and higher depending on the actual reactivity of the MSW

  15. A composite scheme for gas dynamics in Lagrangian coordinates

    SciTech Connect

    Shashkov, M.; Wendroff, B.

    1999-04-10

    One cycle of a composite finite difference scheme is defined as several time steps of an oscillatory scheme such as Lax-Wendroff followed by one step of a diffusive scheme such as Lax-Friedrichs. The authors apply this idea to gas dynamics in Lagrangian coordinates. They show numerical results in two dimensions for Noh`s infinite strength shock problem and the Sedov blast wave problem, and for several one-dimensional problems including a Riemann problem with a contact discontinuity. For Noh`s problem the composite scheme produces a better result than that obtained with a more conventional Lagrangian code.

  16. Gas content and composition of gas hydrate from sediments of the southeastern North American continental margin

    USGS Publications Warehouse

    Lorenson, T.D.; Collett, T.S.

    2000-01-01

    , which contained much less ethane (up to 86 ppmv). Up to 19 ppmv propane and other higher homologues were noted; however, these gases are likely contaminants derived from sediment in some hydrate samples. CO2 concentrations are less in gas hydrate than in the surrounding sediment, likely an artifact of core depressurization, which released CO2 derived from dissolved organic carbon (DIC) into sediment. The isotopic composition of methane from gas hydrate ranges from ??13C of -62.5??? to -70.7??? and ??D of -175??? to -200??? and is identical to the isotopic composition of methane from surrounding sediment. Methane of this isotopic composition is mainly microbial in origin and likely produced by bacterial reduction of bicarbonate. The hydrocarbon gases here are likely the products of early microbial diagenesis. The isotopic composition of CO2 from gas hydrate ranges from ??13C of -5.7 to -6.9, about 15??? lighter than CO2 derived from nearby sediment.

  17. Differences in volatile methyl siloxane (VMS) profiles in biogas from landfills and anaerobic digesters and energetics of VMS transformations.

    PubMed

    Tansel, Berrin; Surita, Sharon C

    2014-11-01

    The objectives of this study were to compare the types and levels of volatile methyl siloxanes (VMS) present in biogas generated in the anaerobic digesters and landfills, evaluate the energetics of siloxane transformations under anaerobic conditions, compare the conditions in anaerobic digesters and municipal solid waste (MSW) landfills which result in differences in siloxane compositions. Biogas samples were collected at the South District Wastewater Treatment Plant and South Dade Landfill in Miami, Florida. In the digester gas, D4 and D5 comprised the bulk of total siloxanes (62% and 27%, respectively) whereas in the landfill gas, the bulk of siloxanes were trimethylsilanol (TMSOH) (58%) followed by D4 (17%). Presence of high levels of TMSOH in the landfill gas indicates that methane utilization may be a possible reaction mechanism for TMSOH formation. The free energy change for transformation of D5 and D4 to TMSOH either by hydrogen or methane utilization are thermodynamically favorable. Either hydrogen or methane should be present at relatively high concentrations for TMSOH formation which explains the high levels present in the landfill gas. The high bond energy and bond distance of the Si-O bond, in view of the atomic sizes of Si and O atoms, indicate that Si atoms can provide a barrier, making it difficult to break the Si-O bonds especially for molecules with specific geometric configurations such as D4 and D5 where oxygen atoms are positioned inside the frame formed by the large Si atoms which are surrounded by the methyl groups.

  18. The ion composition of cooling, variable-density interstellar gas

    NASA Astrophysics Data System (ADS)

    Suchkov, A. A.; Shchekinov, Y. A.

    1986-06-01

    The ion composition of rarefied interstellar gas cooling from about one million K to about 10,000 K is calculated. The time dependence of logarithmic relative ion densities is determined in an isobaric-cooling model and in a model with an initial adiabatic expansion. It is shown that so long as T is greater than 10,000 K, the N(C IV)/N(O VI) ion density ratio may be used to test the origin of nonstable behavior.

  19. Gas Composition Transients in the Cold Vacuum Drying (CVD) Facility

    SciTech Connect

    PACKER, M.J.

    2000-05-10

    The purpose of this document is to evaluate selected problems involving the prediction of transient gas compositions during Cold Vacuum Drying operations. The problems were evaluated to answer specific design questions. The document is formatted as a topical report with each section representing a specific problem solution. The problem solutions are reported in the calculation format specified in HNF-1613, Rev. 0, EP 7.6.

  20. Melt Infiltrated Ceramic Composites (Hipercomp) for Gas Turbine Engine Applications

    SciTech Connect

    Gregory Corman; Krishan Luthra

    2005-09-30

    This report covers work performed under the Continuous Fiber Ceramic Composites (CFCC) program by GE Global Research and its partners from 1994 through 2005. The processing of prepreg-derived, melt infiltrated (MI) composite systems based on monofilament and multifilament tow SiC fibers is described. Extensive mechanical and environmental exposure characterizations were performed on these systems, as well as on competing Ceramic Matrix Composite (CMC) systems. Although current monofilament SiC fibers have inherent oxidative stability limitations due to their carbon surface coatings, the MI CMC system based on multifilament tow (Hi-Nicalon ) proved to have excellent mechanical, thermal and time-dependent properties. The materials database generated from the material testing was used to design turbine hot gas path components, namely the shroud and combustor liner, utilizing the CMC materials. The feasibility of using such MI CMC materials in gas turbine engines was demonstrated via combustion rig testing of turbine shrouds and combustor liners, and through field engine tests of shrouds in a 2MW engine for >1000 hours. A unique combustion test facility was also developed that allowed coupons of the CMC materials to be exposed to high-pressure, high-velocity combustion gas environments for times up to {approx}4000 hours.

  1. Acid gas scrubbing by composite solvent-swollen membranes

    DOEpatents

    Matson, Stephen L.; Lee, Eric K. L.; Friesen, Dwayne T.; Kelly, Donald J.

    1988-01-01

    A composite immobilized liquid membrane suitable for acid gas scrubbing is disclosed. The membrane is a solvent-swollen polymer and a microporous polymeric support, the solvent being selected from a class of highly polar solvents containing at least one atom selected from nitrogen, oxygen, phosphorous and sulfur, and having a boiling point of at least 100.degree. C. and a solubility parameter of from about 7.5 to about 13.5 (cal/cm.sup.3 -atm).sup.1/2. Such solvents are homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. Also disclosed are methods of acid gas scrubbing of high- and low-Btu gas effluents with such solvent-swollen membranes.

  2. Acid gas scrubbing by composite solvent-swollen membranes

    DOEpatents

    Matson, S.L.; Lee, E.K.L.; Friesen, D.T.; Kelly, D.J.

    1988-04-12

    A composite immobilized liquid membrane suitable for acid gas scrubbing is disclosed. The membrane is a solvent-swollen polymer and a microporous polymeric support, the solvent being selected from a class of highly polar solvents containing at least one atom selected from nitrogen, oxygen, phosphorus and sulfur, and having a boiling point of at least 100 C and a solubility parameter of from about 7.5 to about 13.5 (cal/cm[sup 3]-atm)[sup 1/2]. Such solvents are homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. Also disclosed are methods of acid gas scrubbing of high- and low-Btu gas effluents with such solvent-swollen membranes. 3 figs.

  3. ESTIMATE OF GLOBAL METHANE EMISSIONS FROM LANDFILLS AND OPEN DUMPS

    EPA Science Inventory

    The report presents an empirical model to estimate global methane (CH4) emissions from landfills and open dumps based on EPA data from landfill gas (LFG) recovery projects. The EPA CH4 estimates for 1990 range between 19 and 40 teragrams (10 to the 12th power) per year (Tg/yr), w...

  4. Effect of gas composition on octane number of natural gas fuels. Topical report, December 1991-March 1992

    SciTech Connect

    Kubesh, J.T.

    1992-05-01

    Variations in the composition of natural gas fuels are recognized to have a significant impact on the performance of internal combustion engines. In particular, the knock resistance of the fuel is governed by its gas composition. The octane number is a standard measure of the knock resistance of a fuel, and several gas blends were tested to determine their octane numbers. Octane number of natural gas fuels was found to be dependent on gas composition. Several correlations were found between gas composition and the octane number of a fuel, which allow prediction of the motor octane number if gas composition is known. In particular, a good correlation was found between the hydrogen-carbon ratio of the fuel and the octane number. Correlations were also found between measured motor octane numbers and measured methane numbers, as well as between motor octane numbers and predicted methane numbers.

  5. Back-Analyses of Landfill Instability Induced by High Water Level: Case Study of Shenzhen Landfill.

    PubMed

    Peng, Ren; Hou, Yujing; Zhan, Liangtong; Yao, Yangping

    2016-01-01

    In June 2008, the Shenzhen landfill slope failed. This case is used as an example to study the deformation characteristics and failure mode of a slope induced by high water levels. An integrated monitoring system, including water level gauges, electronic total stations, and inclinometers, was used to monitor the slope failure process. The field measurements suggest that the landfill landslide was caused by a deep slip along the weak interface of the composite liner system at the base of the landfill. The high water level is considered to be the main factor that caused this failure. To calculate the relative interface shear displacements in the geosynthetic multilayer liner system, a series of numerical direct shear tests were carried out. Based on the numerical results, the composite lining system simplified and the centrifuge modeling technique was used to quantitatively evaluate the effect of water levels on landfill instability. PMID:26771627

  6. Back-Analyses of Landfill Instability Induced by High Water Level: Case Study of Shenzhen Landfill

    PubMed Central

    Peng, Ren; Hou, Yujing; Zhan, Liangtong; Yao, Yangping

    2016-01-01

    In June 2008, the Shenzhen landfill slope failed. This case is used as an example to study the deformation characteristics and failure mode of a slope induced by high water levels. An integrated monitoring system, including water level gauges, electronic total stations, and inclinometers, was used to monitor the slope failure process. The field measurements suggest that the landfill landslide was caused by a deep slip along the weak interface of the composite liner system at the base of the landfill. The high water level is considered to be the main factor that caused this failure. To calculate the relative interface shear displacements in the geosynthetic multilayer liner system, a series of numerical direct shear tests were carried out. Based on the numerical results, the composite lining system simplified and the centrifuge modeling technique was used to quantitatively evaluate the effect of water levels on landfill instability. PMID:26771627

  7. Back-Analyses of Landfill Instability Induced by High Water Level: Case Study of Shenzhen Landfill.

    PubMed

    Peng, Ren; Hou, Yujing; Zhan, Liangtong; Yao, Yangping

    2016-01-12

    In June 2008, the Shenzhen landfill slope failed. This case is used as an example to study the deformation characteristics and failure mode of a slope induced by high water levels. An integrated monitoring system, including water level gauges, electronic total stations, and inclinometers, was used to monitor the slope failure process. The field measurements suggest that the landfill landslide was caused by a deep slip along the weak interface of the composite liner system at the base of the landfill. The high water level is considered to be the main factor that caused this failure. To calculate the relative interface shear displacements in the geosynthetic multilayer liner system, a series of numerical direct shear tests were carried out. Based on the numerical results, the composite lining system simplified and the centrifuge modeling technique was used to quantitatively evaluate the effect of water levels on landfill instability.

  8. Landfill disposal systems

    PubMed Central

    Slimak, Karen M.

    1978-01-01

    The current status of landfill disposal of hazardous wastes in the United States is indicated by presenting descriptions of six operating landfills. These landfills illustrate the variety of techniques that exist in landfill disposal of hazardous wastes. Although some landfills more effectively isolate hazardous waste than others, all landfills must deal with the following problems. Leachate from hazardous waste landfills is generally highly polluted. Most landfills attempt to contain leachate at the site and prevent its discharge to surface or groundwaters. To retain leachate within a disposal area, subsurface barriers of materials such as concrete, asphalt, butyl rubber, vinyl, and clay are used. It is difficult to assure that these materials can seal a landfill indefinitely. When a subsurface barrier fails, the leachate enters the groundwater in a concentrated, narrow band which may bypass monitoring wells. Once a subsurface barrier has failed, repairs are time-consuming and costly, since the waste above the repair site may have to be removed. The central problem in landfill disposal is leachate control. Recent emphasis has been on developing subsurface barriers to contain the wastes and any leachate. Future emphasis should also be on techniques for removing water from hazardous wastes before they are placed in landfills, and on methods for preventing contact of the wastes with water during and after disposal operations. When leachate is eliminated, the problems of monitoring, and subsurface barrier failure and repair can be addressed, and a waste can be effectively isolated. A surface seal landfill design is recommended for maintaining the dry state of solid hazardous wastes and for controlling leachate. Any impervious liner is utilized over the top of the landfill to prevent surface water from seeping into the waste. The surface barrier is also the site where monitoring and maintenance activities are focused. Barrier failure can be detected by visual

  9. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John C; McComb, Scott T.

    2002-01-01

    The present invention includes a system of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  10. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John; McComb, Scott T.

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  11. Aerobic landfill bioreactor

    SciTech Connect

    Hudgins, M.P.; Bessette, B.J.; March, J.; McComb, S.T.

    2000-02-15

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120 F and 140 F in steady state.

  12. Report: management problems of solid waste landfills in Kuwait.

    PubMed

    Al-Yaqout, Anwar F; Hamoda, Mohamed F

    2002-08-01

    This paper evaluates current operational practices in municipal solid waste landfills in Kuwait to provide existing knowledge on uncontrolled landfilling and associated problems of solid waste disposal in developing countries. The current landfilling practices are safe neither for humans nor for the environment. The landfill sites receive all kinds of wastes such as food wastes, oil products, debris, dead animals, agricultural wastes, chemical wastes, wastewater and sewage sludge. The wastes are dumped, spread and compacted in an uncontrolled manner and cover material is not applied regularly. Dust created within the landfill site and gas emissions cause a public nuisance. The characteristics of leachate formed indicate high organic content and presence of heavy metals, salts and nutrients. There are no provisions for leachate or landfill gas collection at the landfill sites. Recommendations for adjustment in landfill operation have been made in recognition of the transition period that is experienced in proceeding from the past and present to the future management of landfills in Kuwait to safeguard the public health and protect the environment.

  13. Field performance of a geosynthetic clay liner landfill capping system under simulated waste subsidence

    SciTech Connect

    Weiss, W.; Siegmund, M.; Alexiew, D.

    1995-10-01

    A flexible landfill capping system consisting of a 3-D-geocore composite for gas vent, a Geosynthetic Clay Liner (GCL) for sealing and a 3-D-geocore composite for drainage of the vegetation soil was built on a test field at Michelshoehe landfill near Weimar, Germany. At four locations airbags were installed underneath the thin capping system to simulate subsidences. On top of three of these airbags overlaps of the GCL were positioned, for comparison there was no overlap at the fourth location. After hydratation of the GCL the airbags were de-aerated and subsidences occurred with app. 5 % tensile strain in the GCL. For three weeks the test field was intensively sprinkled in intervals. Then horizontal and vertical deformations were measured, but not displacements were registered in the overlaps. The evaluation of the GCL`s permeability showed no significant difference between the locations with and without overlaps.

  14. Carbon-fiber composite molecular sieves for gas separation

    SciTech Connect

    Jagtoyen, M.; Derbyshire, F.

    1996-08-01

    This report describes continuing work on the activation and characterization of formed carbon fiber composites. The composites are produced at the Oak Ridge National Laboratory (ORNL) and activated at the Center for Applied Energy Research (CAER) using steam, CO{sub 2}, or O{sub 2} at different conditions of temperature and time, and with different furnace configurations. The general aims of the project are to produce uniformly activated samples with controlled pore structures for specialist applications such as gas separation and water treatment. In previous work the authors reported that composites produced from isotropic pitch fibers weighing up to 25g can be uniformly activated through the appropriate choice of reaction conditions and furnace configurations. They have now succeeded in uniformly activating composites of dimensions up to 12 x 7 x 6 cm, or up to about 166 gram - a scale-up factor of about six. Part of the work has involved the installation of a new furnace that can accommodate larger composites. Efforts were made to achieve uniform activation in both steam and CO{sub 2}. The authors have also succeeded in producing materials with very uniform and narrow pore size distributions by using a novel method involving low temperature oxygen chemisorption in combination with heat treatment in N{sub 2} at high temperatures. Work has also started on the activation of PAN based carbon fibers and fiber composites with the aim of producing composites with wide pore structures for use as catalyst supports. So far activation of the PAN fiber composites supplied by ORNL has been difficult which is attributed to the low reactivity of the PAN fibers. As a result, studies are now being made of the activation of the PAN fibers to investigate the optimum carbonization and activation conditions for PAN based fibers.

  15. Initial results of detected methane emissions from landfills in the Los Angeles Basin during the COMEX campaign by the Methane Airborne MAPper (MAMAP) instrument and a greenhouse gas in-situ analyser

    NASA Astrophysics Data System (ADS)

    Krautwurst, Sven; Gerilowski, Konstantin; Kolyer, Richard; Jonsson, Haflidi; Krings, Thomas; Horstjann, Markus; Leifer, Ira; Vigil, Sam; Buchwitz, Michael; Schüttemeyer, Dirk; Fladeland, Matthew M.; Burrows, John P.; Bovensmann, Heinrich

    2015-04-01

    Methane (CH4) is the second most important anthropogenic greenhouse gas beside carbon dioxide (CO2). Significant contributors to the global methane budget are fugitive emissions from landfills. Due to the growing world population, it is expected that the amount of waste and, therefore, waste disposal sites will increase in number and size in parts of the world, often adjacent growing megacities. Besides bottom-up modelling, a variety of ground based methods (e.g., flux chambers, trace gases, radial plume mapping, etc.) have been used to estimate (top-down) these fugitive emissions. Because landfills usually are large, sometimes with significant topographic relief, vary temporally, and leak/emit heterogeneously across their surface area, assessing total emission strength by ground-based techniques is often difficult. In this work, we show how airborne based remote sensing measurements of the column-averaged dry air mole fraction of CH4 can be utilized to estimate fugitive emissions from landfills in an urban environment by a mass balance approach. Subsequently, these emission rates are compared to airborne in-situ horizontal cross section measurements of CH4 taken within the planetary boundary layer (PBL) upwind and downwind of the landfill at different altitudes immediately after the remote sensing measurements were finished. Additional necessary parameters (e.g., wind direction, wind speed, aerosols, dew point temperature, etc.) for the data inversion are provided by a standard instrumentation suite for atmospheric measurements aboard the aircraft, and nearby ground-based weather stations. These measurements were part of the CO2 and Methane EXperiment (COMEX), which was executed during the summer 2014 in California and was co-funded by the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). The remote sensing measurements were taken by the Methane Airborne MAPper (MAMAP) developed and operated by the University of Bremen and

  16. Emissions of Nonmethane Organic Compounds at an Illinois (USA) Landfill: Preliminary Field Measurements

    SciTech Connect

    Bogner, J.; Spokas, K.; Niemann, M.; Niemann, L.; Baker, J.

    1997-08-01

    Current US regulatory models for estimating emissions of nonmethane organic compounds (NMOCs) from municipal solid waste (MSW) landfills require field validation to determine if the models are realistic. A project was initiated to begin to develop a field method for direct measurement of landfill NMOC emissions and, concurrently, develop improved sampling and analysis methods for individual NMOCs in landfill gas matrices. Two contrasting field sites at the Greene Valley Landfill, DuPage County, Illinois, USA, were established.

  17. Gas composition measurements in arc heated flowfields via mass spectrometry

    NASA Astrophysics Data System (ADS)

    Willey, Ronald J.; Blake, David J.

    1991-06-01

    Gas compositions for an arc heated flowfield were determined by mass spectrometry on gas samples drawn from the flowfield through a sample probe. Surveys were made across the freestream flow using sample probes made of copper and quartz. Oxygen atoms reaching the mass spectrometer ranged from 6 to 9.4 percent and was a direct function of arc heater current and resultant stream enthalpy. Likewise, mole percents of nitrogen atoms ranged from 13.5 to 19 for total enthalpies of 7.0 to 18.4 MJ/kg. Species gradients existed in both the radial and axial directions. Atomic concentrations were highest near the centerline and at the nozzle exit. A species survey was completed around a shock that was established by a copper blunt body placed in the flowfield. The results showed strong species gradients following the shock edge, with atom mole fractions highest along the shock edge. Overall, the results provide insight into gas composition by point measurements in arc heated flowfields. The results suggest that nitrogen may begin dissociating before all of the oxygen dissociates, and that past assumptions based on frozen chemistry models may be faulty.

  18. Carbon and Noble Gas Isotope Banks in Two-Phase Flow: Changes in Gas Composition During Migration

    NASA Astrophysics Data System (ADS)

    Sathaye, K.; Larson, T.; Hesse, M. A.

    2015-12-01

    In conjunction with the rise of unconventional oil and gas production, there has been a recent rise in interest in noble gas and carbon isotope changes that can occur during the migration of natural gas. Natural gas geochemistry studies use bulk hydrocarbon composition, carbon isotopes, and noble gas isotopes to determine the migration history of gases from source to reservoir, and to trace fugitive gas leaks from reservoirs to shallow groundwater. We present theoretical and experimental work, which helps to explain trends observed in gas composition in various migration scenarios. Noble gases are used as tracers for subsurface fluid flow due to distinct initial compositions in air-saturated water and natural gases. Numerous field studies have observed enrichments and depletions of noble gases after gas-water interaction. A theoretical two-phase gas displacement model shows that differences in noble gas solubility will cause volatile gas components will become enriched at the front of gas plumes, leaving the surrounding residual water stripped of dissolved gases. Changes in hydrocarbon gas composition are controlled by gas solubility in both formation water and residual oil. In addition to model results, we present results from a series of two-phase flow experiments. These results demonstrate the formation of a noble gas isotope banks ahead of a main CO2 gas plume. Additionally, we show that migrating hydrocarbon gas plumes can sweep biogenic methane from groundwater, significantly altering the isotope ratio of the gas itself. Results from multicomponent, two-phase flow experiments qualitatively agree with the theoretical model, and previous field studies. These experimentally verified models for gas composition changes can be used to aid source identification of subsurface gases.

  19. Ultrasensitive Gold Nanostar-Polyaniline Composite for Ammonia Gas Sensing.

    PubMed

    Kumar, Vished; Patil, Vithoba; Apte, Amey; Harale, Namdev; Patil, Pramod; Kulkarni, Sulabha

    2015-12-01

    Gold in the form of bulk metal mostly does not react with gases or liquids at room temperature. On the other hand, nanoparticles of gold are very reactive and useful as catalysts. The reactivity of nanoparticles depends on the size and the morphology of the nanoparticles. Gold nanostars containing copper have rough surfaces and large numbers of active sites due to tips, sides, corners, and large surface area-to-volume ratios due to their branched morphology. Here the sensitivity of the gold nanostar-polyaniline composite (average size of nanostars ∼170 nm) toward ammonia gas has been investigated. For 100 ppm ammonia, the sensitivity of the composite increased to 52% from a mere 7% value for pure polyaniline. The gold nanostar-polyaniline composite even showed a response time as short as 15 s at room temperature. The gold nanostars act as a catalyst in the nanocomposite. The stability and sensitivity at different concentrations and the selectivity for ammonia gas were also investigated.

  20. Ultrasensitive Gold Nanostar-Polyaniline Composite for Ammonia Gas Sensing.

    PubMed

    Kumar, Vished; Patil, Vithoba; Apte, Amey; Harale, Namdev; Patil, Pramod; Kulkarni, Sulabha

    2015-12-01

    Gold in the form of bulk metal mostly does not react with gases or liquids at room temperature. On the other hand, nanoparticles of gold are very reactive and useful as catalysts. The reactivity of nanoparticles depends on the size and the morphology of the nanoparticles. Gold nanostars containing copper have rough surfaces and large numbers of active sites due to tips, sides, corners, and large surface area-to-volume ratios due to their branched morphology. Here the sensitivity of the gold nanostar-polyaniline composite (average size of nanostars ∼170 nm) toward ammonia gas has been investigated. For 100 ppm ammonia, the sensitivity of the composite increased to 52% from a mere 7% value for pure polyaniline. The gold nanostar-polyaniline composite even showed a response time as short as 15 s at room temperature. The gold nanostars act as a catalyst in the nanocomposite. The stability and sensitivity at different concentrations and the selectivity for ammonia gas were also investigated. PMID:26522375

  1. Nitrogen management in bioreactor landfills

    SciTech Connect

    Price, G. Alexander; Barlaz, Morton A.; Hater, Gary R

    2003-07-01

    One scenario for long-term nitrogen management in landfills is ex situ nitrification followed by denitrification in the landfill. The objective of this research was to measure the denitrification potential of actively decomposing and well decomposed refuse. A series of 10-l reactors that were actively producing methane were fed 400 mg NO{sub 3}-N /l every 48 h for periods of 19-59 days. Up to 29 nitrate additions were either completely or largely depleted within 48 h of addition and the denitrification reactions did not adversely affect the leachate pH. Nitrate did inhibit methane production, but the reactors recovered their methane-producing activity with the termination of nitrate addition. In well decomposed refuse, the nitrate consumption rate was reduced but was easily stimulated by the addition of either acetate or an overlayer of fresh refuse. Addition of acetate at five times the amount required to reduce nitrate did not lead to the production of NH{sub 4}{sup +} by dissimilatory nitrate reduction. The most probable number of denitrifying bacteria decreased by about five orders of magnitude during refuse decomposition in a reactor that did not receive nitrate. However, rapid denitrification commenced immediately with nitrate addition. This study shows that the use of a landfill as a bioreactor for the conversion of nitrate to a harmless byproduct, nitrogen gas, is technically viable.

  2. Magnetic roller gas gate employing transonic sweep gas flow to isolate regions of differing gaseous composition or pressure

    DOEpatents

    Doehler, Joachim

    1994-12-20

    Disclosed herein is an improved gas gate for interconnecting regions of differing gaseous composition and/or pressure. The gas gate includes a narrow, elongated passageway through which substrate material is adapted to move between said regions and inlet means for introducing a flow of non-contaminating sweep gas into a central portion of said passageway. The gas gate is characterized in that the height of the passageway and the flow rate of the sweep gas therethrough provides for transonic flow of the sweep gas between the inlet means and at least one of the two interconnected regions, thereby effectively isolating one region, characterized by one composition and pressure, from another region, having a differing composition and/or pressure, by decreasing the mean-free-path length between collisions of diffusing species within the transonic flow region. The gas gate preferably includes a manifold at the juncture point where the gas inlet means and the passageway interconnect.

  3. [Dispersion and analysis of odor pollution in landfill area under the enclosed operation condition].

    PubMed

    Lu, Peng; Wu, Shi-Xing; Dai, Zhi-Feng; Zhang, Xiao-Hui; Su, Zhao-Hui; Zhou, Xiao-Fei; Dai, Zhan-Guo; Lu, Xu-Fei; Zheng, Bin; Shen, Kai; Wei, Pan-Ming

    2013-03-01

    Odor pollution of landfill site is a serious problem accompanied with the urbanization process that influences city life. Generally, odor emission points in landfill boundary are detected by experience, but the pollution intensity, distribution and variation in the scope of landfill boundary are difficulty to describe. In this research, odor emission points were disclosed with equal odor concentration curves that were delineated using electric nose and GPS instrument. The leakage of landfill gas and exhaust emission from biogas incineration torch was the main cause of the odor pollution in landfill area. Gas production evaluation suggested that the improvement of landfill gas consumption is the key point to control the odor pollution at the landfill site.

  4. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    SciTech Connect

    Don Augenstein; Ramin Yazdani; Rick Moore; Michelle Byars; Jeff Kieffer; Professor Morton Barlaz; Rinav Mehta

    2000-02-26

    Controlled landfilling is an approach to manage solid waste landfills, so as to rapidly complete methane generation, while maximizing gas capture and minimizing the usual emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated to more rapid and earlier completion to full potential by improving conditions (principally moisture, but also temperature) to optimize biological processes occurring within the landfill. Gas is contained through use of surface membrane cover. Gas is captured via porous layers, under the cover, operated at slight vacuum. A field demonstration project has been ongoing under NETL sponsorship for the past several years near Davis, CA. Results have been extremely encouraging. Two major benefits of the technology are reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times, more predictably, than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role both in reduction of US greenhouse gas emissions and in US renewable energy. The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 metric tons [tonnes]), sufficient to replicate many heat and compaction characteristics of larger ''full-scale'' landfills. An enhanced demonstration cell has received moisture supplementation to field capacity. This is the maximum moisture waste can hold while still limiting liquid drainage rate to minimal and safely manageable levels. The enhanced landfill module was compared to a parallel control landfill module receiving no moisture additions. Gas recovery has continued for a period of over 4 years. It is quite encouraging that the enhanced cell methane recovery has been close to 10-fold that experienced with conventional

  5. Analysis of gas composition of intravascular bubbles produced by decompression.

    PubMed

    Ishiyama, A

    1983-06-01

    The gas composition of intravascular bubbles produced by decompression was investigated in rabbits using gas chromatography. The animals were exposed to 8 ATA for 30 min. All samples of bubbles were taken from the animals under 0.2 ATA pressure gradient so that no air could enter the sampling system from the outside. The percentage of carbon dioxide in the bubbles tended to decrease at first and then increased with post-decompression time. On the other hand, the percentage of oxygen tended to change in the opposite manner. Actual analysis of bubbles in the living decompressed animals indicates that carbon dioxide may be an outstanding factor in the initiation and early growth of bubbles. In view of this, Haldane's classical maximum supersaturation limit for avoiding decompression sickness should be examined and possibly modified for gases other than nitrogen.

  6. Gas separation by composite solvent-swollen membranes

    DOEpatents

    Matson, S.L.; Lee, E.K.L.; Friesen, D.T.; Kelly, D.J.

    1989-04-25

    There is disclosed a composite immobilized liquid membrane of a solvent-swollen polymer and a microporous organic or inorganic support, the solvent being at least one highly polar solvent containing at least one nitrogen, oxygen, phosphorus or sulfur atom, and having a boiling point of at least 100 C and a specified solubility parameter. The solvent or solvent mixture is homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. The membrane is suitable for acid gas scrubbing and oxygen/nitrogen separation. 3 figs.

  7. Gas separation by composite solvent-swollen membranes

    DOEpatents

    Matson, Stephen L.; Lee, Eric K. L.; Friesen, Dwayne T.; Kelly, Donald J.

    1989-01-01

    There is disclosed a composite immobulized liquid membrane of a solvent-swollen polymer and a microporous organic or inorganic support, the solvent being at least one highly polar solvent containing at least one nitrogen, oxygen, phosphorous or sulfur atom, and having a boiling point of at least 100.degree. C. and a specified solubility parameter. The solvent or solvent mixture is homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. The membrane is suitable for acid gas scrubbing and oxygen/nitrogen separation.

  8. Hydrological and geochemical factors affecting leachate composition in municipal solid waste incinerator bottom ash. Part II. The geochemistry of leachate from Landfill Lostorf, Switzerland

    NASA Astrophysics Data System (ADS)

    Johnson, C. Annette; Kaeppeli, Michael; Brandenberger, Sandro; Ulrich, Andrea; Baumann, Werner

    1999-12-01

    The leachate composition of the Landfill Lostorf, Buchs, Switzerland has been examined as a function rain events and dry periods between November 1994 and November 1996. Discharge and electrical conductivity of the central drainage discharge were monitored continuously, whilst samples for chemical analysis were taken at discrete intervals. The average total concentrations of Na, Cl, K, Mg, Ca and SO 4 are 44.5, 47.1, 11.8, 0.63, 8.2 and 12.4 mM, respectively. During rain events, the leachate is diluted by the preferential flow of rainwater into the drainage discharge. Drainage discharge pH values range between 8.68 and 11.28, the latter under dry conditions. Thermodynamic calculations indicate that CaSO 4, ettringite (3CaOAl 2O 3CaSO 4·32H 2O) and Al(OH) 3 may control the concentrations of the components Ca, SO 4 and Al. Dissolved Si may be in thermodynamic equilibrium with either Ca silicate hydrate or imogolite. Cadmium, Mo, V, Mn and Zn are also diluted during rain events and concentration changes agree with those of conductivity (representing the major constituents). Average concentrations are 0.012, 5.4, 2.3, 0.085, and 0.087 μM, respectively. Components such as Al, Cu, Sb and Cr increase in concentration with increased discharge. Average concentrations are 1.6, 0.27 and 0.21 μM, respectively. For Cu, the explanation lies in its affinity for total organic carbon (TOC). Thermodynamic calculations indicate that whilst dissolution/precipitation reactions with metal hydroxides and carbonates can explain the observed concentrations of Cd, sorption and complexation reactions probably influence the concentrations of Cu, Pb (average measurable concentration 0.013 μM), Zn and Mn. For the oxyanion species such as MoO 4 and WO 4 (average concentration 0.61 μM), it is probable that Ca metallate formation plays a dominant role in determining concentration ranges. Geochemical processes appear to determine concentration ranges and the hydrological factors, the

  9. Biotic systems to mitigate landfill methane emissions.

    PubMed

    Huber-Humer, Marion; Gebert, Julia; Hilger, Helene

    2008-02-01

    Landfill gases produced during biological degradation of buried organic wastes include methane, which when released to the atmosphere, can contribute to global climate change. Increasing use of gas collection systems has reduced the risk of escaping methane emissions entering the atmosphere, but gas capture is not 100% efficient, and further, there are still many instances when gas collection systems are not used. Biotic methane mitigation systems exploit the propensity of some naturally occurring bacteria to oxidize methane. By providing optimum conditions for microbial habitation and efficiently routing landfill gases to where they are cultivated, a number of bio-based systems, such as interim or long-term biocovers, passively or actively vented biofilters, biowindows and daily-used biotarps, have been developed that can alone, or with gas collection, mitigate landfill methane emissions. This paper reviews the science that guides bio-based designs; summarizes experiences with the diverse natural or engineered substrates used in such systems; describes some of the studies and field trials being used to evaluate them; and discusses how they can be used for better landfill operation, capping, and aftercare.

  10. Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials

    SciTech Connect

    Rachor, Ingke; Gebert, Julia; Groengroeft, Alexander; Pfeiffer, Eva-Maria

    2011-05-15

    The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm{sup -3}, reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100 g CH{sub 4} m{sup -2} d{sup -1}, covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH{sub 4} m{sup -2} d{sup -1} and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity

  11. Molecular Analysis of Methanogen Richness in Landfill and Marshland Targeting 16S rDNA Sequences.

    PubMed

    Yadav, Shailendra; Kundu, Sharbadeb; Ghosh, Sankar K; Maitra, S S

    2015-01-01

    Methanogens, a key contributor in global carbon cycling, methane emission, and alternative energy production, generate methane gas via anaerobic digestion of organic matter. The methane emission potential depends upon methanogenic diversity and activity. Since they are anaerobes and difficult to isolate and culture, their diversity present in the landfill sites of Delhi and marshlands of Southern Assam, India, was analyzed using molecular techniques like 16S rDNA sequencing, DGGE, and qPCR. The sequencing results indicated the presence of methanogens belonging to the seventh order and also the order Methanomicrobiales in the Ghazipur and Bhalsawa landfill sites of Delhi. Sequences, related to the phyla Crenarchaeota (thermophilic) and Thaumarchaeota (mesophilic), were detected from marshland sites of Southern Assam, India. Jaccard analysis of DGGE gel using Gel2K showed three main clusters depending on the number and similarity of band patterns. The copy number analysis of hydrogenotrophic methanogens using qPCR indicates higher abundance in landfill sites of Delhi as compared to the marshlands of Southern Assam. The knowledge about "methanogenic archaea composition" and "abundance" in the contrasting ecosystems like "landfill" and "marshland" may reorient our understanding of the Archaea inhabitants. This study could shed light on the relationship between methane-dynamics and the global warming process. PMID:26568700

  12. Integrating landfill bioreactors, partial nitritation and anammox process for methane recovery and nitrogen removal from leachate

    PubMed Central

    Sun, Faqian; Su, Xiaomei; Kang, Tingting; Wu, Songwei; Yuan, Mengdong; Zhu, Jing; Zhang, Xiayun; Xu, Fang; Wu, Weixiang

    2016-01-01

    A new process consisting of a landfill bioreactor, partial-nitritation (PN) and the anammox process has been developed for landfill leachate treatment. In this study, the landfill bioreactor exhibited excellent performance in methane-rich biogas recovery, with a specific biogas yield of 0.47 L gas g−1 COD and methane percentages of 53–76%. PN was achieved in the aerobic reactor by high free ammonia (101 ± 83 mg NH3 L−1) inhibition for nitrite-oxidizing bacteria, and the desired PN effluent composition (effluent nitrite: ammonium ratio of 1.1 ± 0.3) was controlled by adjusting the alkalinity concentration per unit of ammonium oxidized to approximately 14.3 mg CaCO3 mg−1 N in the influent. The startup of anammox process was successfully achieved with a membrane bioreactor in 160 d, and a maximum nitrogen removal rate of 216 mg N L−1 d−1 was attained for real landfill leachate treatment. The quantitative polymerase chain reaction results confirmed that the cell-specific anammox activity was approximately 68–95 fmol N cell−1 d−1, which finally led to the stable operation of the system. PMID:27279481

  13. Integrating landfill bioreactors, partial nitritation and anammox process for methane recovery and nitrogen removal from leachate.

    PubMed

    Sun, Faqian; Su, Xiaomei; Kang, Tingting; Wu, Songwei; Yuan, Mengdong; Zhu, Jing; Zhang, Xiayun; Xu, Fang; Wu, Weixiang

    2016-01-01

    A new process consisting of a landfill bioreactor, partial-nitritation (PN) and the anammox process has been developed for landfill leachate treatment. In this study, the landfill bioreactor exhibited excellent performance in methane-rich biogas recovery, with a specific biogas yield of 0.47 L gas g(-1) COD and methane percentages of 53-76%. PN was achieved in the aerobic reactor by high free ammonia (101 ± 83 mg NH3 L(-1)) inhibition for nitrite-oxidizing bacteria, and the desired PN effluent composition (effluent nitrite: ammonium ratio of 1.1 ± 0.3) was controlled by adjusting the alkalinity concentration per unit of ammonium oxidized to approximately 14.3 mg CaCO3 mg(-1) N in the influent. The startup of anammox process was successfully achieved with a membrane bioreactor in 160 d, and a maximum nitrogen removal rate of 216 mg N L(-1) d(-1) was attained for real landfill leachate treatment. The quantitative polymerase chain reaction results confirmed that the cell-specific anammox activity was approximately 68-95 fmol N cell(-1) d(-1), which finally led to the stable operation of the system. PMID:27279481

  14. Molecular Analysis of Methanogen Richness in Landfill and Marshland Targeting 16S rDNA Sequences.

    PubMed

    Yadav, Shailendra; Kundu, Sharbadeb; Ghosh, Sankar K; Maitra, S S

    2015-01-01

    Methanogens, a key contributor in global carbon cycling, methane emission, and alternative energy production, generate methane gas via anaerobic digestion of organic matter. The methane emission potential depends upon methanogenic diversity and activity. Since they are anaerobes and difficult to isolate and culture, their diversity present in the landfill sites of Delhi and marshlands of Southern Assam, India, was analyzed using molecular techniques like 16S rDNA sequencing, DGGE, and qPCR. The sequencing results indicated the presence of methanogens belonging to the seventh order and also the order Methanomicrobiales in the Ghazipur and Bhalsawa landfill sites of Delhi. Sequences, related to the phyla Crenarchaeota (thermophilic) and Thaumarchaeota (mesophilic), were detected from marshland sites of Southern Assam, India. Jaccard analysis of DGGE gel using Gel2K showed three main clusters depending on the number and similarity of band patterns. The copy number analysis of hydrogenotrophic methanogens using qPCR indicates higher abundance in landfill sites of Delhi as compared to the marshlands of Southern Assam. The knowledge about "methanogenic archaea composition" and "abundance" in the contrasting ecosystems like "landfill" and "marshland" may reorient our understanding of the Archaea inhabitants. This study could shed light on the relationship between methane-dynamics and the global warming process.

  15. Integrating landfill bioreactors, partial nitritation and anammox process for methane recovery and nitrogen removal from leachate

    NASA Astrophysics Data System (ADS)

    Sun, Faqian; Su, Xiaomei; Kang, Tingting; Wu, Songwei; Yuan, Mengdong; Zhu, Jing; Zhang, Xiayun; Xu, Fang; Wu, Weixiang

    2016-06-01

    A new process consisting of a landfill bioreactor, partial-nitritation (PN) and the anammox process has been developed for landfill leachate treatment. In this study, the landfill bioreactor exhibited excellent performance in methane-rich biogas recovery, with a specific biogas yield of 0.47 L gas g‑1 COD and methane percentages of 53–76%. PN was achieved in the aerobic reactor by high free ammonia (101 ± 83 mg NH3 L‑1) inhibition for nitrite-oxidizing bacteria, and the desired PN effluent composition (effluent nitrite: ammonium ratio of 1.1 ± 0.3) was controlled by adjusting the alkalinity concentration per unit of ammonium oxidized to approximately 14.3 mg CaCO3 mg‑1 N in the influent. The startup of anammox process was successfully achieved with a membrane bioreactor in 160 d, and a maximum nitrogen removal rate of 216 mg N L‑1 d‑1 was attained for real landfill leachate treatment. The quantitative polymerase chain reaction results confirmed that the cell-specific anammox activity was approximately 68–95 fmol N cell‑1 d‑1, which finally led to the stable operation of the system.

  16. Are closed landfills free of CH_{4} emissions? A case study of Arico's landfill, Tenerife, Canary Islands

    NASA Astrophysics Data System (ADS)

    Barrancos, José; Cook, Jenny; Phillips, Victoria; Asensio-Ramos, María; Melián, Gladys; Hernández, Pedro A.; Pérez, Nemesio M.

    2016-04-01

    Landfills are authentic chemical and biological reactors that introduce in the environment a wide amount of gas pollutants (CO2, CH4, volatile organic compounds, etc.) and leachates. Even after years of being closed, a significant amount of landfill gas could be released to the atmosphere through the surface in a diffuse form, also known as non-controlled emission. The study of the spatial-temporal distribution of diffuse emissions provides information of how a landfill degassing takes place. The main objective of this study was to estimate the diffuse uncontrolled emission of CH4 into the atmosphere from the closed Arico's landfill (0.3 km2) in Tenerife Island, Spain. To do so, a non-controlled biogenic gas emission survey of nearly 450 sampling sites was carried out during August 2015. Surface gas sampling and surface landfill CO2 efflux measurements were carried out at each sampling site by means of a portable non-dispersive infrared spectrophotometer (NDIR) model LICOR Li800 following the accumulation chamber method. Landfill gases, CO2 and CH4, were analyzed using a double channel VARIAN 4900 micro-GC. The CH4 efflux was computed combining CO2 efflux and CH4/CO2 ratio in the landfill's surface gas. To quantify the total CH4 emission, CH4 efflux contour map was constructed using sequential Gaussian simulation (sGs) as interpolation method. The total diffuse CH4 emission was estimated in 2.2 t d-1, with CH4 efflux values ranging from 0-922 mg m-2 d-1. This type of studies provides knowledge of how a landfill degasses and serves to public and private entities to establish effective systems for extraction of biogas. This aims not only to achieve higher levels of controlled gas release from landfills resulting in a higher level of energy production but also will contribute to minimize air pollution caused by them.

  17. Are closed landfills free of CH_{4} emissions? A case study of Arico's landfill, Tenerife, Canary Islands

    NASA Astrophysics Data System (ADS)

    Barrancos, José; Cook, Jenny; Phillips, Victoria; Asensio-Ramos, María; Melián, Gladys; Hernández, Pedro A.; Pérez, Nemesio M.

    2016-04-01

    Landfills are authentic chemical and biological reactors that introduce in the environment a wide amount of gas pollutants (CO2, CH4, volatile organic compounds, etc.) and leachates. Even after years of being closed, a significant amount of landfill gas could be released to the atmosphere through the surface in a diffuse form, also known as non-controlled emission. The study of the spatial-temporal distribution of diffuse emissions provides information of how a landfill degassing takes place. The main objective of this study was to estimate the diffuse uncontrolled emission of CH4 into the atmosphere from the closed Arico's landfill (0.3 km2) in Tenerife Island, Spain. To do so, a non-controlled biogenic gas emission survey of nearly 450 sampling sites was carried out during August 2015. Surface gas sampling and surface landfill CO2 efflux measurements were carried out at each sampling site by means of a portable non-dispersive infrared spectrophotometer (NDIR) model LICOR Li800 following the accumulation chamber method. Landfill gases, CO2 and CH4, were analyzed using a double channel VARIAN 4900 micro-GC. The CH4 efflux was computed combining CO2 efflux and CH4/CO2 ratio in the landfill's surface gas. To quantify the total CH4 emission, CH4 efflux contour map was constructed using sequential Gaussian simulation (sGs) as interpolation method. The total diffuse CH4 emission was estimated in 2.2 t d‑1, with CH4 efflux values ranging from 0-922 mg m‑2 d‑1. This type of studies provides knowledge of how a landfill degasses and serves to public and private entities to establish effective systems for extraction of biogas. This aims not only to achieve higher levels of controlled gas release from landfills resulting in a higher level of energy production but also will contribute to minimize air pollution caused by them.

  18. Reducing Open Cell Landfill Methane Emissions with a Bioactive Alternative Daily

    SciTech Connect

    Helene Hilger; James Oliver; Jean Bogner; David Jones

    2009-03-31

    Methane and carbon dioxide are formed in landfills as wastes degrade. Molecule-for-molecule, methane is about 20 times more potent than carbon dioxide at trapping heat in the earth's atmosphere, and thus, it is the methane emissions from landfills that are scrutinized. For example, if emissions composed of 60% methane and 40% carbon dioxide were changed to a mix that was 40% methane and 60% carbon dioxide, a 30% reduction in the landfill's global warming potential would result. A 10% methane, 90% carbon dioxide ratio will result in a 75% reduction in global warming potential compared to the baseline. Gas collection from a closed landfill can reduce emissions, and it is sometimes combined with a biocover, an engineered system where methane oxidizing bacteria living in a medium such as compost, convert landfill methane to carbon dioxide and water. Although methane oxidizing bacteria merely convert one greenhouse gas (methane) to another (carbon dioxide), this conversion can offer significant reductions in the overall greenhouse gas contribution, or global warming potential, associated with the landfill. What has not been addressed to date is the fact that methane can also escape from a landfill when the active cell is being filled with waste. Federal regulations require that newly deposited solid waste to be covered daily with a 6 in layer of soil or an alternative daily cover (ADC), such as a canvas tarp. The aim of this study was to assess the feasibility of immobilizing methane oxidizing bacteria into a tarp-like matrix that could be used for alternative daily cover at open landfill cells to prevent methane emissions. A unique method of isolating methanotrophs from landfill cover soil was used to create a liquid culture of mixed methanotrophs. A variety of prospective immobilization techniques were used to affix the bacteria in a tarp-like matrix. Both gel encapsulation of methanotrophs and gels with liquid cores containing methanotrophs were readily made but

  19. NOVEL COMPOSITE MEMBRANES AND PROCESS FOR NATURAL GAS UPGRADING

    SciTech Connect

    Johann LeRoux

    2002-02-01

    The first phase of this project involved the development of a high performance composite membranes for the treatment of natural gas. The objective of the second phase is to demonstrate the commercial potential of a full-size membrane module in a pilot scale field test. This phase is undertaken jointly with our commercial partner, UOP LLC. At the conclusion of Phase I, two composite membrane products had been developed for the enrichment (sweetening) of natural gas. The one was a low pressure membrane with a high CO{sub 2}/CH{sub 4} separation factor that falls within the target range of 25-30 (at 50 C) set for the program. This is a significant improvement over current commercial membranes that have separation factors of around 18-19. The second membrane had excellent high pressure capability and good contamination resistance, with a separation factor of 20-22. Based on the performance and the economic evaluation of the newly developed membranes, and with the input of UOP and DOE, it was decided to devote the demonstration phase of the program to the field testing and commercial evaluation of natural gas dehydration membranes. Due to the events of September 11, the program was also extended by 6 months until June 30, 2002. In Phase II, UOP has essentially completed preparation of the field test site. Site preparation included the re-design of the test system, purchase and installation of analytical equipment, and making the necessary piping and other hardware changes. IMS has produced two commercial sized dehydration membrane modules for the field tests. These have been successfully tested up to pressures expected in the field tests, and the modules have been shipped to the test site. The remainder of the program will comprise performance testing of the membrane modules, evaluation of the results and submission of the final report with recommendations.

  20. The new Waste Law: Challenging opportunity for future landfill operation in Indonesia.

    PubMed

    Meidiana, Christia; Gamse, Thomas

    2011-01-01

    The Waste Law No. 18/2008 Article 22 and 44 require the local governments to run environmentally sound landfill. Due to the widespread poor quality of waste management in Indonesia, this study aimed to identify the current situation by evaluating three selected landfills based on the ideal conditions of landfill practices, which are used to appraise the capability of local governments to adapt to the law. The results indicated that the local governments have problems of insufficient budget, inadequate equipment, uncollected waste and unplanned future landfill locations. All of the selected landfills were partially controlled landfills with open dumping practices predominating. In such inferior conditions the implementation of sanitary landfill is not necessarily appropriate. The controlled landfill is a more appropriate solution as it offers lower investment and operational costs, makes the selection of a new landfill site unnecessary and can operate with a minimum standard of infrastructure and equipment. The sustainability of future landfill capacity can be maintained by utilizing the old landfill as a profit-oriented landfill by implementing a landfill gas management or a clean development mechanism project. A collection fee system using the pay-as-you-throw principle could increase the waste income thereby financing municipal solid waste management. PMID:20935025

  1. Risk assessment of an old landfill regarding the potential of gaseous emissions--a case study based on bioindication, FT-IR spectroscopy and thermal analysis.

    PubMed

    Tintner, Johannes; Smidt, Ena; Böhm, Katharina; Matiasch, Lydia

    2012-12-01

    Risk assessment of two sections (I and II) of an old landfill (ALH) in Styria (Austria) in terms of reactivity of waste organic matter and the related potential of gaseous emissions was performed using conventional parameters and innovative tools to verify their effectiveness in practice. The ecological survey of the established vegetation at the landfill surface (plant sociological relevés) indicated no relevant emissions over a longer period of time. Statistical evaluation of conventional parameters reveals that dissolved organic carbon (DOC), respiration activity (RA(4)), loss of ignition (LOI) and total inorganic carbon (TIC) mostly influence the variability of the gas generation sum (GS(21)). According to Fourier Transform Infrared (FT-IR) spectral data and the results of the classification model the reactivity potential of the investigated sections is very low which is in accordance with the results of plant sociological relevés and biological tests. The interpretation of specific regions in the FT-IR spectra was changed and adapted to material characteristics. Contrary to mechanically-biologically treated (MBT) materials, where strong aliphatic methylene bands indicate reactivity, they are rather assigned to the C-H vibrations of plastics in old landfill materials. This assumption was confirmed by thermal analysis and the characteristic heat flow profile of plastics containing landfill samples. Therefore organic carbon contents are relatively high compared to other stable landfills as shown by a prediction model for TOC contents based on heat flow profiles and partial least squares regression (PLS-R). The stability of the landfill samples, expressed by the relation of CO(2) release and enthalpies, was compared to unreactive landfills, archeological samples, earthlike materials and hardly degradable organic matter. Due to the material composition and the aging process the landfill samples are located between hardly degradable, but easily combustible

  2. Risk assessment of an old landfill regarding the potential of gaseous emissions--a case study based on bioindication, FT-IR spectroscopy and thermal analysis.

    PubMed

    Tintner, Johannes; Smidt, Ena; Böhm, Katharina; Matiasch, Lydia

    2012-12-01

    Risk assessment of two sections (I and II) of an old landfill (ALH) in Styria (Austria) in terms of reactivity of waste organic matter and the related potential of gaseous emissions was performed using conventional parameters and innovative tools to verify their effectiveness in practice. The ecological survey of the established vegetation at the landfill surface (plant sociological relevés) indicated no relevant emissions over a longer period of time. Statistical evaluation of conventional parameters reveals that dissolved organic carbon (DOC), respiration activity (RA(4)), loss of ignition (LOI) and total inorganic carbon (TIC) mostly influence the variability of the gas generation sum (GS(21)). According to Fourier Transform Infrared (FT-IR) spectral data and the results of the classification model the reactivity potential of the investigated sections is very low which is in accordance with the results of plant sociological relevés and biological tests. The interpretation of specific regions in the FT-IR spectra was changed and adapted to material characteristics. Contrary to mechanically-biologically treated (MBT) materials, where strong aliphatic methylene bands indicate reactivity, they are rather assigned to the C-H vibrations of plastics in old landfill materials. This assumption was confirmed by thermal analysis and the characteristic heat flow profile of plastics containing landfill samples. Therefore organic carbon contents are relatively high compared to other stable landfills as shown by a prediction model for TOC contents based on heat flow profiles and partial least squares regression (PLS-R). The stability of the landfill samples, expressed by the relation of CO(2) release and enthalpies, was compared to unreactive landfills, archeological samples, earthlike materials and hardly degradable organic matter. Due to the material composition and the aging process the landfill samples are located between hardly degradable, but easily combustible

  3. Management of landfill leachate: The legacy of European Union Directives.

    PubMed

    Brennan, R B; Healy, M G; Morrison, L; Hynes, S; Norton, D; Clifford, E

    2016-09-01

    Landfill leachate is the product of water that has percolated through waste deposits and contains various pollutants, which necessitate effective treatment before it can be released into the environment. In the last 30years, there have been significant changes in landfill management practices in response to European Union (EU) Directives, which have led to changes in leachate composition, volumes produced and treatability. In this study, historic landfill data, combined with leachate characterisation data, were used to determine the impacts of EU Directives on landfill leachate management, composition and treatability. Inhibitory compounds including ammonium (NH4-N), cyanide, chromium, nickel and zinc, were present in young leachate at levels that may inhibit ammonium oxidising bacteria, while arsenic, copper and silver were present in young and intermediate age leachate at concentrations above inhibitory thresholds. In addition, the results of this study show that while young landfills produce less than 50% of total leachate by volume in the Republic of Ireland, they account for 70% of total annual leachate chemical oxygen demand (COD) load and approximately 80% of total 5-day biochemical oxygen demand (BOD5) and NH4-N loads. These results show that there has been a decrease in the volume of leachate produced per tonne of waste landfilled since enactment of the Landfill Directive, with a trend towards increased leachate strength (particularly COD and BOD5) during the initial five years of landfill operation. These changes may be attributed to changes in landfill management practices following the implementation of the Landfill Directive. However, this study did not demonstrate the impact of decreasing inputs of biodegradable municipal waste on leachate composition. Increasingly stringent wastewater treatment plant (WWTP) emission limit values represent a significant threat to the sustainability of co-treatment of leachate with municipal wastewater. In addition

  4. The influence of atmospheric pressure on landfill methane emissions.

    PubMed

    Czepiel, P M; Shorter, J H; Mosher, B; Allwine, E; McManus, J B; Harriss, R C; Kolb, C E; Lamb, B K

    2003-01-01

    Landfills are the largest source of anthropogenic methane (CH4) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH4 emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH4 emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m3 CH4 min(-1). A simple regression model of our results was used to calculate an annual emission rate of 8.4 x 10(6) m3 CH4 year(-1). These data, along with CH4 oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH4 generation at this landfill. A reported gas collection rate of 7.1 x 10(6) m3 CH4 year(-1) and an estimated annual rate of CH4 oxidation by cover soils of 1.2 x 10(6) m3 CH4 year(-1) resulted in a calculated annual CH4 generation rate of 16.7 x 10(6) m3 CH4 year(-1). These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential.

  5. Stochastic modelling of landfill processes incorporating waste heterogeneity and data uncertainty.

    PubMed

    Zacharof, A I; Butler, A P

    2004-01-01

    A landfill is a very complex heterogeneous environment and as such it presents many modelling challenges. Attempts to develop models that reproduce these complexities generally involve the use of large numbers of spatially dependent parameters that cannot be properly characterised in the face of data uncertainty. An alternative method is presented, which couples a simplified microbial degradation model with a stochastic hydrological and contaminant transport model. This provides a framework for incorporating the complex effects of spatial heterogeneity within the landfill in a simplified manner, along with other key variables. A methodology for handling data uncertainty is also integrated into the model structure. Illustrative examples of the model's output are presented to demonstrate effects of data uncertainty on leachate composition and gas volume prediction.

  6. Mitigation of methane emission from an old unlined landfill in Klintholm, Denmark using a passive biocover system.

    PubMed

    Scheutz, Charlotte; Pedersen, Rasmus Broe; Petersen, Per Haugsted; Jørgensen, Jørgen Henrik Bjerre; Ucendo, Inmaculada Maria Buendia; Mønster, Jacob G; Samuelsson, Jerker; Kjeldsen, Peter

    2014-07-01

    Methane generated at landfills contributes to global warming and can be mitigated by biocover systems relying on microbial methane oxidation. As part of a closure plan for an old unlined landfill without any gas management measures, an innovative biocover system was established. The system was designed based on a conceptual model of the gas emission patterns established through an initial baseline study. The study included construction of gas collection trenches along the slopes of the landfill where the majority of the methane emissions occurred. Local compost materials were tested as to their usefulness as bioactive methane oxidizing material and a suitable compost mixture was selected. Whole site methane emission quantifications based on combined tracer release and downwind measurements in combination with several local experimental activities (gas composition within biocover layers, flux chamber based emission measurements and logging of compost temperatures) proved that the biocover system had an average mitigation efficiency of approximately 80%. The study showed that the system also had a high efficiency during winter periods with temperatures below freezing. An economic analysis indicated that the mitigation costs of the biocover system were competitive to other existing greenhouse gas mitigation options.

  7. Landfills for the 21st century

    SciTech Connect

    Poland, R. )

    1994-01-01

    In the next 10 years, the role of landfills will not change significantly. Landfills are, and will continue to be, the cornerstone of any waste services system. A number of factors will, however, cause adjustments in the way landfills function. The character of the waste is also changing. Mankind will see more treated industrial residue in future years. Certain types of these materials have, in the past, gone to hazardous waste disposal sites. These are non-hazardous wastes, but generators found a certain comfort in sending them to hazardous waste facilities that had double composite liners, leachate collection, and financial assurance. With the new technical standards and environmental security of sanitary landfills, there will be a reluctance on the part of generators to pay a premium to send this waste to a hazardous waste site. There is also a growing interest in treating characteristic'' hazardous waste to a level where it is no longer hazardous and can be placed in a sanitary landfill.

  8. Tunable composite membranes for gas separations. Quarterly technical progress report, May--July 1996

    SciTech Connect

    Ferraris, J.P.; Balkus, K.J. Jr.; Musselman, I.H.

    1996-08-05

    Significant progress has been made in the synthesis and characterization of conducting polymer composite membranes for gas separations. Zeolite/polyalkylthiophene composite membranes have been prepared and characterized for zeolite NaY.

  9. Tunable composite membranes for gas separations. Quarterly technical progress report, November 1, 1995--January 31, 1996

    SciTech Connect

    Ferraris, J.P.; Balkus, K.J. Jr.; Musselman, I.H.

    1996-01-01

    Research continued on composite membranes for gas separations. This report describes work in the following: instrument development; polymer synthesis; membrane fabrication; and permeability measurements.

  10. Global Biogenic Emission of Carbon Dioxide from Landfills

    NASA Astrophysics Data System (ADS)

    Lima, R.; Nolasco, D.; Meneses, W.; Salazar, J.; Hernández, P.; Pérez, N.

    2002-12-01

    Human-induced increases in the atmospheric concentrations of greenhouse gas components have been underway over the past century and are expected to drive climate change in the coming decades. Carbon dioxide was responsible for an estimated 55 % of the antropogenically driven radiactive forcing of the atmosphere in the 1980s and is predicted to have even greater importance over the next century (Houghton et al., 1990). A highly resolved understanding of the sources and sinks of atmospheric CO2, and how they are affected by climate and land use, is essential in the analysis of the global carbon cycle and how it may be impacted by human activities. Landfills are biochemical reactors that produce CH4 and CO2 emissions due to anaerobic digestion of solid urban wastes. Estimated global CH4 emission from landfills is about 44 millions tons per year and account for a 7.4 % of all CH4 sources (Whiticar, 1989). Observed CO2/CH4 molar ratios from landfill gases lie within the range of 0.7-1.0; therefore, an estimated global biogenic emission of CO2 from landfills could reach levels of 11.2-16 millions tons per year. Since biogas extraction systems are installed for extracting, purifying and burning the landfill gases, most of the biogenic gas emission to the atmosphere from landfills occurs through the surface environment in a diffuse and disperse form, also known as non-controlled biogenic emission. Several studies of non-controlled biogenic gas emission from landfills showed that CO2/CH4 weight ratios of surface landfill gases, which are directly injected into the atmosphere, are about 200-300 times higher than those observed in the landfill wells, which are usually collected and burned by gas extraction systems. This difference between surface and well landfill gases is mainly due to bacterial oxidation of the CH4 to CO2 inducing higher CO2/CH4 ratios for surface landfill gases than those well landfill gases. Taking into consideration this observation, the global biogenic

  11. Modelling biogas production of solid waste: application of the BGP model to a synthetic landfill

    NASA Astrophysics Data System (ADS)

    Rodrigo-Ilarri, Javier; Segura-Sobrino, Francisco

    2013-04-01

    Production of biogas as a result of the decomposition of organic matter included on solid waste landfills is still an issue to be understood. Reports on this matter are rarely included on the engineering construction projects of solid waste landfills despite it can be an issue of critical importance while operating the landfill and after its closure. This paper presents an application of BGP (Bio-Gas-Production) model to a synthetic landfill. The evolution in time of the concentrations of the different chemical compounds of biogas is studied. Results obtained show the impact on the air quality of different management alternatives which are usually performed in real landfills.

  12. Gas composition and isotopic geochemistry of cuttings, core, and gas hydrate from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well

    USGS Publications Warehouse

    Lorenson, T.D.

    1999-01-01

    Molecular and isotopic composition of gases from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well demonstrate that the in situ gases can be divided into three zones composed of mixtures of microbial and thermogenic gases. Sediments penetrated by the well are thermally immature; thus the sediments are probably not a source of thermogenic gas. Thermogenic gas likely migrated from depths below 5000 m. Higher concentrations of gas within and beneath the gas hydrate zone suggest that gas hydrate is a partial barrier to gas migration. Gas hydrate accumulations occur wholly within zone 3, below the base of permafrost. The gas in gas hydrate resembles, in part, the thermogenic gas in surrounding sediments and gas desorbed from lignite. Gas hydrate composition implies that the primary gas hydrate form is Structure I. However, Structure II stabilizing gases are more concentrated and isotopically partitioned in gas hydrate relative to the sediment hosting the gas hydrate, implying that Structure II gas hydrate may be present in small quantities.

  13. The impact of air-fuel mixture composition on SI engine performance during natural gas and producer gas combustion

    NASA Astrophysics Data System (ADS)

    Przybyła, G.; Postrzednik, S.; Żmudka, Z.

    2016-09-01

    The paper summarizers results of experimental tests of SI engine fuelled with gaseous fuels such as, natural gas and three mixtures of producer gas substitute that simulated real producer gas composition. The engine was operated under full open throttle and charged with different air-fuel mixture composition (changed value of air excess ratio). The spark timing was adjusted to obtain maximum brake torque (MBT) for each fuel and air-fuel mixture. This paper reports engine indicated performance based on in-cylinder, cycle resolved pressure measurements. The engine performance utilizing producer gas in terms of indicated efficiency is increased by about 2 percentage points when compared to fuelling with natural gas. The engine power de-rating when producer gas is utilized instead the natural gas, varies from 24% to 28,6% under stoichiometric combustion conditions. For lean burn (λ=1.5) the difference are lower and varies from 22% to 24.5%.

  14. Clean Air Act Title III accidental emission release risk management program, and how it applies to landfills

    SciTech Connect

    Hibbard, C.S.

    1999-07-01

    On June 20, 1996, EPA promulgated regulations pursuant to Title III of the Clean Air Act (CAA) Amendments of 1990 (Section 112(r)(7) of the CAA). The rule, contained in 40 CFR Part 68, is called Accidental Release Prevention Requirements: Risk Management Programs, and is intended to improve accident prevention and emergency response practices at facilities that store and/or use hazardous substances. Methane is a designated highly hazardous chemical (HHC) under the rule. The rule applies to facilities that have 10,000 pounds of methane or more in any process, roughly equivalent to about 244,000 cubic feet of methane. The US EPA has interpreted this threshold quantity as applying to landfill gas within landfills. This paper presents an overview of the Accidental Release Prevention regulations, and how landfills are affected by the requirements. This paper describes methodologies for calculating the threshold quantity of landfill gas in a landfill. Methane is in landfill gas as a mixture. Because landfill gas can burn readily, down to concentrations of about five percent methane, the entire landfill gas mixture must be treated as the regulated substance, and counts toward the 10,000-pound threshold. It is reasonable to assume that the entire landfill gas collection system, active or passive, is filled with landfill gas, and that a calculation of the volume of the system would be a calculation of the landfill gas present in the process on the site. However, the US EPA has indicated that there are some instances in which pore space gas should be included in this calculation. This paper presents methods available to calculate the amount of pore space gas in a landfill, and how to determine how much of that gas might be available for an explosion. The paper goes through how to conduct the release assessment to determine the worst-case hazard zone around the landfill.

  15. Quantification of landfill emissions to air: a case study of the Ano Liosia landfill site in the greater Athens area.

    PubMed

    Paraskaki, Ioanna; Lazaridis, Mihalis

    2005-06-01

    Fugitive pollutant emissions from municipal solid waste landfills have the potential to cause annoyance and health impacts in the surrounding residential areas. The overall objective of this research was to perform an assessment of fugitive pollutant emissions and a dispersion analysis downwind of a specific landfill site. The study was performed at the closed Ano Liosia landfill site which is located in the greater Athens area. The human exposure from priority to health-risk pollutants emitted from landfill, such as vinyl chloride and benzene, was estimated by the landfill gas emission LandGEM 2.01 software combined with the atmospheric long-term dispersion model ISC3-LT. The emission and meteorological conditions under which the models were applied referred to the worst-case scenario. This scenario was used for the evaluation of the maximum human exposure assessed beyond the Ano Liosia landfill towards the residential areas. The above scenario provides the minimum downwind distance of the health-risk zone which is calculated to be equal to 1.5 km from the landfill. Within this distance the assessed air pollutant concentration for several air pollutants was significantly above the World Health Organization reference lifetime exposure health criteria. Finally, the applied methodology was used in the Ano Liosia landfill, where atmospheric concentrations of pollutants measured in the field were compared with model predictions. PMID:15997481

  16. Quantification of landfill emissions to air: a case study of the Ano Liosia landfill site in the greater Athens area.

    PubMed

    Paraskaki, Ioanna; Lazaridis, Mihalis

    2005-06-01

    Fugitive pollutant emissions from municipal solid waste landfills have the potential to cause annoyance and health impacts in the surrounding residential areas. The overall objective of this research was to perform an assessment of fugitive pollutant emissions and a dispersion analysis downwind of a specific landfill site. The study was performed at the closed Ano Liosia landfill site which is located in the greater Athens area. The human exposure from priority to health-risk pollutants emitted from landfill, such as vinyl chloride and benzene, was estimated by the landfill gas emission LandGEM 2.01 software combined with the atmospheric long-term dispersion model ISC3-LT. The emission and meteorological conditions under which the models were applied referred to the worst-case scenario. This scenario was used for the evaluation of the maximum human exposure assessed beyond the Ano Liosia landfill towards the residential areas. The above scenario provides the minimum downwind distance of the health-risk zone which is calculated to be equal to 1.5 km from the landfill. Within this distance the assessed air pollutant concentration for several air pollutants was significantly above the World Health Organization reference lifetime exposure health criteria. Finally, the applied methodology was used in the Ano Liosia landfill, where atmospheric concentrations of pollutants measured in the field were compared with model predictions.

  17. Quantifying Spatial and Temporal Variability of Methane Emissions from a Complex Area Source: Case Study of a Central Indiana Landfill

    NASA Astrophysics Data System (ADS)

    Cambaliza, M. O. L.; Bogner, J. E.; Green, R. B.; Shepson, P. B.; Thoma, E. D.; Foster-wittig, T. A.; Spokas, K.

    2014-12-01

    Atmospheric methane is a powerful greenhouse gas that is responsible for about 17% of the total direct radiative forcing from long-lived greenhouse gases (IPCC 2013). While the global emission of methane is relatively well quantified, the temporal and spatial variability of methane emissions from individual area or point sources are still poorly understood. Using 4 field methods (aircraft-based mass balance, tracer correlation, vertical radial plume mapping, and static chambers) and a new field-validated process-based model (California Landfill Methane Inventory Model, CALMIM 5.4), we investigated both the total emissions from a central Indiana landfill as well as the partitioned emissions inclusive of methanotrophic oxidation for the various cover soils. This landfill is an upwind source for the city of Indianapolis, so the resolution of m2 to km2 scale emissions, as well as understanding the temporal variability for this complex area source, contributes to improved regional inventory calculations. Emissions for the site as a whole were measured using both an aircraft-based mass balance approach as well as a ground-based tracer correlation method, permitting direct comparison of the strengths, limitations, and uncertainties of these two approaches. Because US landfills are highly-engineered and composed of daily, intermediate, and final cover areas with differing thicknesses, composition, and implementation of gas recovery, we also expected different emission signatures and strengths from the various cover areas. Thus we also deployed static chambers and vertical radial plume mapping to quantify the spatial variability of emissions from the thinner daily and intermediate cover areas. Understanding the daily, seasonal and annual emission rates from a landfill is not trivial, and usually requires a combination of measurement and modeling approaches. Thus, our unique data set provides an opportunity to gain an improved understanding of the emissions from a complex

  18. Quantifying Methane Abatement Efficiency at Three Municipal Solid Waste Landfills; Final Report

    EPA Science Inventory

    Measurements were conducted at three municipal solid waste landfills to compare fugitive methane emissions from the landfill cells to the quantity of collected gas (i.e., gas collection efficiency). The measurements were conducted over a multi-week sampling campaign using EPA Oth...

  19. Biotic landfill cover treatments for mitigating methane emissions.

    PubMed

    Hilgeri, Helene; Humer, Marion

    2003-05-01

    Landfill methane (CH4) emissions have been cited as one of the anthropogenic gas releases that can and should be controlled to reduce global climate change. This article reviews recent research that identifies ways to enhance microbial consumption of the gas in the aerobic portion of a landfill cover. Use of these methods can augment CH4 emission reductions achieved by gas collection or provide a sole means to consume CH4 at small landfills that do not have active gas collection systems. Field studies indicate that high levels of CH4 removal can be achieved by optimizing natural soil microbial processes. Further, during biotic conversion, not all of the CH4 carbon is converted to carbon dioxide (CO2) gas and released to the atmosphere; some of it will be sequestered in microbial biomass. Because biotic covers can employ residuals from other municipal processes, financial benefits can also accrue from avoided costs for residuals disposal.

  20. Methods of Sensing Land Pollution from Sanitary Landfills

    NASA Technical Reports Server (NTRS)

    Nosanov, Myron Ellis; Bowerman, Frank R.

    1971-01-01

    Major cities are congested and large sites suitable for landfill development are limited. Methane and other gases are produced at most sanitary landfills and dumps. These gases may migrate horizontally and vertically and have caused fatalities. Monitoring these gases provides data bases for design and construction of safe buildings on and adjacent to landfills. Methods of monitoring include: (1) a portable combustible gas indicator; and (2) glass flasks valved to allow simultaneous exhaust of the flask and aspiration of the sample into the flask. Samples are drawn through tubing from probes as deep as twenty-five feet below the surface.

  1. Municipal landfill leachate management

    SciTech Connect

    Kusterer, T.; Willson, R.; Bruce, S.C.; Tissue, E. Lou, P.J.

    1998-12-31

    From 1995 to 1997, the Montgomery County Leachate Pretreatment Facility (MCLPF) has successfully pretreated in excess of 18,000,000 gallons of leachate generated by the county`s municipal solid waste landfill. The collection system directs leachate from the original landfill. The collection system directs leachate from the original landfill, the new lined section, and the ash cell to the leachate pump station. The leachate, prior to being pumped to the leachate pretreatment system, is equalized in two storage lagoons with a combined capacity of more than 5,000,000 gallons. The innovative leachate treatment system, incorporating a biological reactor system equipped with a submerged fixed-film reactor using a patented Matrix Biological Film (MBF) media, continues to provide excellent pretreatment results for the leachate generated at the Oaks Landfill in Montgomery County, Maryland. In 1995 and 1996, the system responded to the substantial challenges imposed by the changing characteristics of the material being landfilled and by the significant amounts of incinerator ash, received in 1995 from the county`s resource recovery facility (RRF), which influenced the influent leachate characteristics.

  2. Numerical studies of gas composition differentiation during gas hydrate formation: An application to the IODP site 1327

    NASA Astrophysics Data System (ADS)

    Yuncheng, C.; Chen, D.

    2014-12-01

    Structure I methane hydrate is the most common type found in nature. Structure I gas hydrate has two types of cages that gas molecules may be hosted. Because the larger cavities filled with ethane would be more stable than those filled by methane (Sloan and Koh, 2008), the larger cavities preferentially enclose ethane during the formation of gas hydrate, which results gas composition differentiation during gas hydrate formation. Based on the principle of gas composition differentiation, we establish a numerical model for the gas composition differentiation between methane and ethane during gas hydrate accumulation and applied the model to IODP site 1327. The simulation shows that the gas composition differentiation only occurs at the interval where gas hydrate presents. The lowest methane/ethane (C1/C2) point indicates the bottom of hydrate zone, and the composition differentiation produces the upward increase of C1/C2 within the gas hydrate zone. The C1/C2 reaches the largest value at the top occurrence of gas hydrate and keeps relative stable above the top occurrence of gas hydrate. The top and bottom occurrence of gas hydrate indicated by the inflection points of the C1/C2 profile are similar to those indicated by the negative anomalies of measured chloride concentrations (Riedel et al., 2006). By comparing with the measured C1/C2, the differentiation coefficient (kh=Xe,h/Xe,w, Xe,h is C1/C2 of the formed gas hydrate, Xe,w [mol/kg] is the concentration of ethane in water ) is calculated to 70 kg/mol. The top occurrence of gas hydrate indicated by the C1/C2 profile also confines the water flux to be 0.4kg/m2-year, similar to that confined by the chloride profile. To best fit the measured C1/C2 profile, the methane flux is calculated to 0.04mol/m2-year. Therefore, the C1/C2 profile could be used to obtain the gas hydrate accumulation information. Acknowledgments:This study was supported by Chinese National Science Foundation (grant 41303044, 91228206 ) References

  3. 30 CFR 36.43 - Determination of exhaust-gas composition.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... volume, of Pittsburgh natural gas (see footnote 3) in the air. Test observations shall include the rate... prescribed by MSHA to determine the volume of air (ventilation) required to dilute the exhaust gas (see § 36... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Determination of exhaust-gas composition....

  4. 30 CFR 36.43 - Determination of exhaust-gas composition.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... volume, of Pittsburgh natural gas (see footnote 3) in the air. Test observations shall include the rate... prescribed by MSHA to determine the volume of air (ventilation) required to dilute the exhaust gas (see § 36... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Determination of exhaust-gas composition....

  5. Composite nuclear fuel fabrication methodology for gas fast reactors

    NASA Astrophysics Data System (ADS)

    Vasudevamurthy, Gokul

    An advanced fuel form for use in Gas Fast Reactors (GFR) was investigated. Criteria for the fuel includes operation at high temperature (˜1400°C) and high burnup (˜150 MWD/MTHM) with effective retention of fission products even during transient temperatures exceeding 1600°C. The GFR fuel is expected to contain up to 20% transuranics for a closed fuel cycle. Earlier evaluations of reference fuels for the GFR have included ceramic-ceramic (cercer) dispersion type composite fuels of mixed carbide or nitride microspheres coated with SiC in a SiC matrix. Studies have indicated that ZrC is a potential replacement for SiC on account of its higher melting point, increased fission product corrosion resistance and better chemical stability. The present work investigated natural uranium carbide microspheres in a ZrC matrix instead of SiC. Known issues of minor actinide volatility during traditional fabrication procedures necessitated the investigation of still high temperature but more rapid fabrication techniques to minimize these anticipated losses. In this regard, fabrication of ZrC matrix by combustion synthesis from zirconium and graphite powders was studied. Criteria were established to obtain sufficient matrix density with UC microsphere volume fractions up to 30%. Tests involving production of microspheres by spark erosion method (similar to electrodischarge machining) showed the inability of the method to produce UC microspheres in the desired range of 300 to 1200 mum. A rotating electrode device was developed using a minimum current of 80A and rotating at speeds up to 1500 rpm to fabricate microspheres between 355 and 1200 mum. Using the ZrC process knowledge, UC electrodes were fabricated and studied for use in the rotating electrode device to produce UC microspheres. Fabrication of the cercer composite form was studied using microsphere volume fractions of 10%, 20%, and 30%. The macrostructure of the composite and individual components at various stages were

  6. The volatile composition of comets as inferred from gas production

    NASA Astrophysics Data System (ADS)

    McKay, Adam Joseph

    Comets are small (1-10 km in radius) icy objects that orbit the Sun on highly eccentric orbits. The composition of comets has been relatively unalterred since their formation 4.5 billion years ago due to their small size and their cold storage in the Kuiper Belt and Oort Cloud. This makes comets "fossils" that can be studied in order to understand the physical conditions and composition of our Solar System during its infancy. Specifically, studying the volatile (ice) composition of comets can place constraints on molecule formation during the planetary formation stage and volatile transport to the inner Solar System. However, for most comets we must infer the volatile composition of the nucleus from gas present in the coma. The composition of the coma is alterred by physical and chemical processes, so the composition of the coma does not exactly reflect that of the nucleus. In this thesis we present analysis of observations of comets 103P/Hartley and C/2009 P1 Garradd in an effort to understand the physical and chemical processes operating in cometary comae. We obtained optical and NIR spectra in an effort to understand the gas production of comets Hartley and Garradd. We employed the ARCES instrument mounted on the ARC 3.5-meter telescope at Apache Point Observatory in Sunspot, NM to acquire optical spectra, while we used the CSHELL instrument mounted on NASA IRTF on Mauna Kea in Hawaii to acquire NIR spectra. We started our analysis with studies of atomic oxygen using the optical spectra and of CO and H2O using the NIR spectra. Specifically, the 5577 A, 6300, and 6300 A lines can potentially used as a proxy for CO2 in comets, which is very imporant because CO2 cannot be observed from the ground directly. Our analysis of the oxygen lines in several comets confirms that analysis of the oxygen line intensities can be employed to obtain quantitative measurements of CO2 in comets, though the accuracy of this method still needs to be firmly established. We also

  7. Carbon Dioxide Gas Sensing Application of GRAPHENE/Y2O3 Quantum Dots Composite

    NASA Astrophysics Data System (ADS)

    Nemade, K. R.; Waghuley, S. A.

    Graphene/Y2O3 quantum dots (QDs) composite was investigated towards the carbon dioxide (CO2) gas at room temperature. Graphene synthesized by electrochemical exfoliation of graphite. The composite prepared by mixing 20-wt% graphene into the 1 g Y2O3 in organic medium (acetone). The chemiresistor of composite prepared by screen-printing on glass substrate. The optimum value of sensing response (1.08) was showed by 20-wt% graphene/Y2O3 QDs composite. The excellent stability with optimum sensing response evidenced for the composite. The gas sensing mechanism discussed on the basis of electron transfer reaction.

  8. Microemulsion impregnated catalyst composite and use thereof in a synthesis gas conversion process

    DOEpatents

    Abrevaya, H.; Targos, W.M.

    1987-12-22

    A catalyst composition is described for synthesis gas conversion comprising a ruthenium metal component deposited on a support carrier wherein the average metal particle size is less than about 100 A. The method of manufacture of the composition via a reverse micelle impregnation technique and the use of the composition in a Fischer-Tropsch conversion process is also disclosed.

  9. Microemulsion impregnated catalyst composite and use thereof in a synthesis gas conversion process

    DOEpatents

    Abrevaya, Hayim; Targos, William M.

    1987-01-01

    A catalyst composition for synthesis gas conversion comprising a ruthenium metal component deposited on a support carrier wherein the average metal particle size is less than about 100 A. The method of manufacture of the composition via a reverse micelle impregnation technique and the use of the composition in a Fischer-Tropsch conversion process is also disclosed.

  10. Lubrication contributes to improved landfill cogeneration plant operation

    SciTech Connect

    1995-10-01

    The Prince George`s county, Maryland, cogeneration plant consists of three lean-burn, 12-cylinder, Waukesha 5790GL turbocharged gas engines, each powering an 850 kW Kato generator. Four Waukesha F1197G engines run gas compressors that draw and compress gas from the landfill, pumping an average of 28000 m{sup 3}/day at 6.2 bar from 29 wells. Landfill gas is 50% methane, 30% carbon dioxide, 10% nitrogen and 10% other gas constituents. These other gas constituents consist of 160 chemical compounds, many of which are very destructive to engines and other equipment. Probably the worst of these are the total organic halide expressed as chloride (TOH/CL), formed from the decomposition of household cleaning preparations and other materials containing chlorides. Landfill gas also contains an abundance of water, which combines not only with the TOH/CLs but with oxides of nitrogen, which are by-products of the combustion process, to form acids. To handle the highly contaminated landfill gas, the Waukesha Engine Division and people from Curtis Engine and Equipment modified the equipment and maintenance practices. One of the first changes was in lubrication. Curtis switched from a standard gas engine oil to Mobile Pegasus 446 oil, an SAE 40 oil that has a total base number (TBN) of 9.5, because of its extended acid-neutralizing capabilities.

  11. Generating CO{sub 2}-credits through landfill in situ aeration

    SciTech Connect

    Ritzkowski, M.; Stegmann, R.

    2010-04-15

    Landfills are some of the major anthropogenic sources of methane emissions worldwide. The installation and operation of gas extraction systems for many landfills in Europe and the US, often including technical installations for energy recovery, significantly reduced these emissions during the last decades. Residual landfill gas, however, is still continuously produced after the energy recovery became economically unattractive, thus resulting in ongoing methane emissions for many years. By landfill in situ aeration these methane emissions can be widely avoided both, during the aeration process as well as in the subsequent aftercare period. Based on model calculations and online monitoring data the amount of avoided CO{sub 2-eq}. can be determined. For an in situ aerated landfill in northern Germany, acting as a case study, 83-95% (depending on the kind and quality of top cover) of the greenhouse gas emission potential could be reduced under strictly controlled conditions. Recently the United Nations Framework Convention on Climate Change (UNFCCC) has approved a new methodology on the 'Avoidance of landfill gas emissions by in situ aeration of landfills' (). Based on this methodology landfill aeration projects might be considered for generation of Certified Emission Reductions (CERs) in the course of CDM projects. This paper contributes towards an evaluation of the potential of landfill aeration for methane emissions reduction.

  12. Optimization of diagnostic microarray for application in analysing landfill methanotroph communities under different plant covers.

    PubMed

    Stralis-Pavese, Nancy; Sessitsch, Angela; Weilharter, Alexandra; Reichenauer, Thomas; Riesing, Johann; Csontos, József; Murrell, J Colin; Bodrossy, Levente

    2004-04-01

    Landfill sites are responsible for 6-12% of global methane emission. Methanotrophs play a very important role in decreasing landfill site methane emissions. We investigated the methane oxidation capacity and methanotroph diversity in lysimeters simulating landfill sites with different plant vegetations. Methane oxidation rates were 35 g methane m-2 day-1 or higher for planted lysimeters and 18 g methane m-2 day-1 or less for bare soil controls. Best methane oxidation, as displayed by gas depth profiles, was found under a vegetation of grass and alfalfa. Methanotroph communities were analysed at high throughput and resolution using a microbial diagnostic microarray targeting the particulate methane monooxygenase (pmoA) gene of methanotrophs and functionally related bacteria. Members of the genera Methylocystis and Methylocaldum were found to be the dominant members in landfill site simulating lysimeters. Soil bacterial communities in biogas free control lysimeters, which were less abundant in methanotrophs, were dominated by Methylocaldum. Type Ia methanotrophs were found only in the top layers of bare soil lysimeters with relatively high oxygen and low methane concentrations. A competetive advantage of type II methanotrophs over type Ia methanotrophs was indicated under all plant covers investigated. Analysis of average and individual results from parallel samples was used to identify general trends and variations in methanotroph community structures in relation to depth, methane supply and plant cover. The applicability of the technology for the detection of environmental perturbations was proven by an erroneous result, where an unexpected community composition detected with the microarray indicated a potential gas leakage in the lysimeter being investigated.

  13. Group-specific quantification of methanotrophs in landfill gas-purged laboratory biofilters by tyramide signal amplification-fluorescence in situ hybridization.

    PubMed

    Wang, Hong; Einola, Juha; Heinonen, Mirja; Kulomaa, Markku; Rintala, Jukka

    2008-09-01

    The aim of this study was to quantitatively analyse methanotrophs in two laboratory landfill biofilters at different biofilter depths and at temperatures which mimicked the boreal climatic conditions. Both biofilters were dominated by type I methanotrophs. The biofilter depth profiles showed that type I methanotrophs occurred in the upper layer, where relatively high O(2) and low CH(4) concentrations were present, whereas type II methanotrophs were mostly distributed in the zone with high CH(4) and low O(2) concentrations. The number of type I methanotrophic cells declined when the temperature was raised from 15 degrees C to 23 degrees C, but increased when lowered to 5 degrees C. A slight decrease in type II methanotrophs was also observed when the temperature was raised from 15 degrees C to 23 degrees C, whereas cell numbers remained constant when lowered to 5 degrees C. The results indicated that low temperature conditions favored both type I and type II methanotrophs in the biofilters.

  14. Post-closure care of engineered municipal solid waste landfills.

    PubMed

    Bagchi, Amalendu; Bhattacharya, Abhik

    2015-03-01

    Post-closure care is divided into perpetual care (PPC) and long-term care (LTC). Guidelines for post-closure care and associated costs are important for engineered municipal solid waste (MSW) landfills. In many states in the USA, landfill owners are required to set aside funds for 30-40 years of LTC. Currently there are no guidelines for PPC, which is also required. We undertook a pilot study, using two landfills (note: average landfill capacity 2.5 million MT MSW waste) in Wisconsin, to establish an approach for estimating the LTC period using field data and PPC funding need. Statistical analysis of time versus concentration data of selected leachate parameters showed that the concentration of most parameters is expected to be at or below the preventive action limit of groundwater and leachate volume will be very low, within 40 years of the LTC period. The gas extraction system may need to be continued for more than 100 years. Due to lack of data no conclusion could be made regarding adequacy of the LTC period for the groundwater monitoring system. The final cover must be maintained for perpetuity. The pilot study shows that although technology is available, the financial liability of maintaining a 'Dry Tomb' design for landfills is significantly higher than commonly perceived. The paper will help landfill professionals to estimate realistic post-closure funding and to develop field-based policies for LTC and PPC of engineered MSW landfills. PMID:25687915

  15. Attenuation of landfill leachate at two uncontrolled landfills

    NASA Astrophysics Data System (ADS)

    Lee, Jin-Yong; Cheon, Jeong-Yong; Kwon, Hyung-Pyo; Yoon, Hee-Sung; Lee, Seong-Sun; Kim, Jong-Ho; Park, Joung-Ku; Kim, Chang-Gyun

    2006-12-01

    Attenuation characteristics of landfill leachate were examined for two uncontrolled landfills in Korea. The two landfills containing municipal wastes without appropriate bottom liner and leachate treatment system have different landfill age, waste volume, and most importantly different hydrogeologic settings. One landfill (Cheonan landfill) is situated in an open flat area while the other (Wonju landfill) is located in a valley. Variations of various parameters including dissolved organic carbon (DOC), dissolved oxygen (DO), alkalinity, pH, electrical conductivity (EC), redox potential (ORP), ammonia (NH3), nitrate (NO{3/-}), sulfate (SO{4/2-}), and chloride (Cl-) were examined along groundwater flow path. All these parameters were analyzed every month for a year. In the interior of the landfills, typical anaerobic conditions revealed by low DO and NO3 concentrations, negative ORP values, high NH3, alkalinity, and Cl- concentrations were observed. Generally, higher levels of contaminants (DOC, NH3, and Cl-) were detected in the dry season while they were greatly lowered in the wet season. Significantly, large decrease of Cl- concentration in the wet season indicates that the dilution or mixing is one of dominant attenuation mechanisms of leachate. But detailed variation behaviors in the two landfills are different and they were largely dependent on permeability of surface and subsurface layers. The intermediately permeable surface of the landfills receives part of direct rainfall infiltration but most rainwater is lost to fast runoff. The practically impermeable surface of clayey silt (paddy field) at immediately adjacent to the Cheonan landfill boundary prevented direct rainwater infiltration and hence redox condition of the ground waters were largely affected by that of the upper landfill and the less permeable materials beneath the paddy fields prohibited dispersion of the landfill leachate into down gradient area. In the Wonju landfill, there are three

  16. Landfill modelling in LCA - a contribution based on empirical data.

    PubMed

    Obersteiner, Gudrun; Binner, Erwin; Mostbauer, Peter; Salhofer, Stefan

    2007-01-01

    Landfills at various stages of development, depending on their age and location, can be found throughout Europe. The type of facilities goes from uncontrolled dumpsites to highly engineered facilities with leachate and gas management. In addition, some landfills are designed to receive untreated waste, while others can receive incineration residues (MSWI) or residues after mechanical biological treatment (MBT). Dimension, type and duration of the emissions from landfills depend on the quality of the disposed waste, the technical design, and the location of the landfill. Environmental impacts are produced by the leachate (heavy metals, organic loading), emissions into the air (CH(4), hydrocarbons, halogenated hydrocarbons) and from the energy or fuel requirements for the operation of the landfill (SO(2) and NO(x) from the production of electricity from fossil fuels). To include landfilling in an life-cycle assessment (LCA) approach entails several methodological questions (multi-input process, site-specific influence, time dependency). Additionally, no experiences are available with regard to mid-term behaviour (decades) for the relatively new types of landfill (MBT landfill, landfill for residues from MSWI). The present paper focuses on two main issues concerning modelling of landfills in LCA: Firstly, it is an acknowledged fact that emissions from landfills may prevail for a very long time, often thousands of years or longer. The choice of time frame in the LCA of landfilling may therefore clearly affect the results. Secondly, the reliability of results obtained through a life-cycle assessment depends on the availability and quality of Life Cycle Inventory (LCI) data. Therefore the choice of the general approach, using multi-input inventory tool versus empirical results, may also influence the results. In this paper the different approaches concerning time horizon and LCI will be introduced and discussed. In the application of empirical results, the presence of

  17. Effects of gas composition in headspace and bicarbonate concentrations in media on gas and methane production, degradability, and rumen fermentation using in vitro gas production techniques.

    PubMed

    Patra, Amlan Kumar; Yu, Zhongtang

    2013-07-01

    Headspace gas composition and bicarbonate concentrations in media can affect methane production and other characteristics of rumen fermentation in in vitro gas production systems, but these 2 important factors have not been evaluated systematically. In this study, these 2 factors were investigated with respect to gas and methane production, in vitro digestibility of feed substrate, and volatile fatty acid (VFA) profile using in vitro gas production techniques. Three headspace gas compositions (N2+ CO2+ H2 in the ratio of 90:5:5, CO2, and N2) with 2 substrate types (alfalfa hay only, and alfalfa hay and a concentrate mixture in a 50:50 ratio) in a 3×2 factorial design (experiment 1) and 3 headspace compositions (N2, N2 + CO2 in a 50:50 ratio, and CO2) with 3 bicarbonate concentrations (80, 100, and 120 mM) in a 3×3 factorial design (experiment 2) were evaluated. In experiment 1, total gas production (TGP) and net gas production (NGP) was the lowest for CO2, followed by N2, and then the gas mixture. Methane concentration in headspace gas after fermentation was greater for CO2 than for N2 and the gas mixture, whereas total methane production (TMP) and net methane production (NMP) were the greatest for CO2, followed by the gas mixture, and then N2. Headspace composition did not affect in vitro digestibility or the VFA profile, except molar percentages of propionate, which were greater for CO2 and N2 than for the gas mixture. Methane concentration in headspace gas, TGP, and NGP were affected by the interaction of headspace gas composition and substrate type. In experiment 2, increasing concentrations of CO2 in the headspace decreased TGP and NGP quadratically, but increased the concentrations of methane, NMP, and in vitro fiber digestibility linearly, and TMP quadratically. Fiber digestibility, TGP, and NGP increased linearly with increasing bicarbonate concentrations in the medium. Concentrations of methane and NMP were unaffected by bicarbonate concentration, but

  18. Near Vent Volcanic Plume Measurement by a Portable Multi-Gas-Sensor System to Estimate Volcanic Gas Composition

    NASA Astrophysics Data System (ADS)

    Shinohara, H.

    2006-12-01

    Near vent plume measurement technique by the use of the Portable Multi-Gas-Sensor System was developed to obtain volcanic gas composition of the major components including H2O, CO2, SO2, H2S and H2. By the combination with the Alkaline Filter Technique, the near vent plume measurement can provide almost full set of the volcanic gas composition including also HCl and HF. The Portable Multi-Gas-Sensor System measures concentration of the volcanic gas species by pumping the atmosphere (plume) through IR H2O-CO2 gas analyzer, SO2, H2S and H2 chemical sensors. The full system weight including battery and data logger is about 5 kg and can be easily carried in a backpack to the volcano summit. Among the various advantages and disadvantages of this techniques to other techniques such as the FT-IR measurements and the air-borne plume measurements with various gas analyzers, the most important advantage of the Portable Multi-Gas-Sensor System is the ability of the near vent measurement which enables the quantitative estimate of the H2O content in the volcanic gas. Since H2O content in the atmosphere is large and variable, a large mixing ratio of the volcanic gas in the plume is necessary to quantify the H2O excess over the atmospheric content. The atmospheric H2O content commonly ranges 5,000-20,000 ppm often with about 10% fluctuation whereas the CO2 content is about 370 ppm with minor (1 ppm) changes. Therefore we can quantify the excess CO2 content even at <1 ppm level, but we need at least 500 times larger excess H2O content derived from the volcanic gas for the quantification. By the near vent plume measurements, we could obtain the volcanic gas compositions of various volcanoes including Miyakejima, Asama and Villarrica as well as Etna whose gas composition is quite H2O-poor of H2O/CO2=1. Since H2O is commonly the most abundant volatile components both in the volcanic gases and magmas, and its solubility is quantitatively well constrained, the measured composition can

  19. GAS CHROMATOGRAPHIC RETENTION PARAMETERS DATABASE FOR REFRIGERANT MIXTURE COMPOSITION MANAGEMENT

    EPA Science Inventory

    Composition management of mixed refrigerant systems is a challenging problem in the laboratory, manufacturing facilities, and large refrigeration machinery. Ths issue of composition management is especially critical for the maintenance of machinery that utilizes zeotropic mixture...

  20. Composite hubs for low cost gas turbine engines

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1977-01-01

    A detailed stress analysis was performed using NASTRAN to demonstrate theoretically the adequacy of composite hubs for low cost turbine engine applications. Composite hubs are adequate for this application from the steady state stress view point.

  1. Effects of natural gas composition on ignition delay under diesel conditions

    NASA Astrophysics Data System (ADS)

    Naber, J. D.; Siebers, D. L.; Dijulio, S. S.; Westbrook, C. K.

    1993-12-01

    Effects of variations in natural gas composition on autoignition of natural gas under direct-injection (DI) diesel engine conditions were studied experimentally in a constant-volume combustion vessel and computationally using a chemical kinetic model. Four fuel blends were investigated: pure methane, a capacity weighted mean natural gas, a high ethane content natural gas, and a natural gas with added propane typical of peak shaving conditions. Experimentally measured ignition delays were longest for pure methane and became progressively shorter as ethane and propane concentrations increased. At conditions characteristic of a DI compression ignition natural gas engine at Top Dead Center (CR = 23:1, p = 6.8 MPa, T = 1150K), measured ignition delays for the four fuels varied from 1.8 ms for the peak shaving and high ethane gases to 2.7 ms for pure methane. Numerically predicted variations in ignition delay as a function of natural gas composition agreed with these measurements.

  2. Effects of natural gas composition on ignition delay under diesel conditions

    SciTech Connect

    Naber, J.D.; Siebers, D.L.; Di Julio, S.S.; Westbrook, C.K.

    1993-12-03

    Effects of variations in natural gas composition on autoignition of natural gas under direct-injection (DI) diesel engine conditions were studied experimentally in a constant-volume combustion vessel and computationally using a chemical kinetic model. Four fuel blends were investigated: pure methane, a capacity weighted mean natural gas, a high ethane content natural gas, and a natural gas with added propane typical of peak shaving conditions. Experimentally measured ignition delays were longest for pure methane and became progressively shorter as ethane and propane concentrations increased. At conditions characteristic of a DI compression ignition natural gas engine at Top Dead Center (CR=23:1, p = 6.8 MPa, T = 1150K), measured ignition delays for the four fuels varied from 1.8 ms for the peak shaving and high ethane gases to 2.7 ms for pure methane. Numerically predicted variations in ignition delay as a function of natural gas composition agreed with these measurements.

  3. Development of computer simulations for landfill methane recovery

    SciTech Connect

    Massmann, J.W.; Moore, C.A.; Sykes, R.M.

    1981-12-01

    Two- and three-dimensional finite-difference computer programs simulating methane recovery systems in landfills have been developed. These computer programs model multicomponent combined pressure and diffusional flow in porous media. Each program and the processes it models are described in this report. Examples of the capabilities of each program are also presented. The two-dimensional program was used to simulate methane recovery systems in a cylindrically shaped landfill. The effects of various pump locations, geometries, and extraction rates were determined. The three-dimensional program was used to model the Puente Hills landfill, a field test site in southern California. The biochemical and microbiological details of methane generation in landfills are also given. Effects of environmental factors, such as moisture, oxygen, temperature, and nutrients on methane generation are discussed and an analytical representation of the gas generation rate is developed.

  4. Short-term landfill methane emissions dependency on wind.

    PubMed

    Delkash, Madjid; Zhou, Bowen; Han, Byunghyun; Chow, Fotini K; Rella, Chris W; Imhoff, Paul T

    2016-09-01

    Short-term (2-10h) variations of whole-landfill methane emissions have been observed in recent field studies using the tracer dilution method for emissions measurement. To investigate the cause of these variations, the tracer dilution method is applied using 1-min emissions measurements at Sandtown Landfill (Delaware, USA) for a 2-h measurement period. An atmospheric dispersion model is developed for this field test site, which is the first application of such modeling to evaluate atmospheric effects on gas plume transport from landfills. The model is used to examine three possible causes of observed temporal emissions variability: temporal variability of surface wind speed affecting whole landfill emissions, spatial variability of emissions due to local wind speed variations, and misaligned tracer gas release and methane emissions locations. At this site, atmospheric modeling indicates that variation in tracer dilution method emissions measurements may be caused by whole-landfill emissions variation with wind speed. Field data collected over the time period of the atmospheric model simulations corroborate this result: methane emissions are correlated with wind speed on the landfill surface with R(2)=0.51 for data 2.5m above ground, or R(2)=0.55 using data 85m above ground, with emissions increasing by up to a factor of 2 for an approximately 30% increase in wind speed. Although the atmospheric modeling and field test are conducted at a single landfill, the results suggest that wind-induced emissions may affect tracer dilution method emissions measurements at other landfills. PMID:26896003

  5. Aeration of the teuftal landfill: Field scale concept and lab scale simulation.

    PubMed

    Ritzkowski, Marco; Walker, Beat; Kuchta, Kerstin; Raga, Roberto; Stegmann, Rainer

    2016-09-01

    Long lasting post-closure care (PCC) is often the major financial burden for operators of municipal solid waste (MSW) landfills. Beside costs for the installation and maintenance of technical equipment and barriers, in particular long term treatment of leachate and landfill gas has to be paid from capital surplus. Estimations based on laboratory experiments project time periods of many decades until leachate quality allows for direct discharge (i.e. no need for further purification). Projections based on leachate samples derived from the last 37years for 35 German landfills confirm these assumption. Moreover, the data illustrate that in particular ammonium nitrogen concentrations are likely to fall below limit values only after a period of 300years. In order to avoid long lasting PCC the operator of Teuftal landfill, located in the Swiss canton Bern, decided to biologically stabilize the landfill by means of a combined in situ aeration and moisturization approach. In December 2014 the aeration started at a landfill section containing approximately 30% of the total landfill volume. From summer 2016 onwards the remaining part of the landfill will be aerated. Landfill aeration through horizontal gas and leachate drains is carried out for the first time in field scale in Europe. The technical concept is described in the paper. Parallel to field scale aeration, investigations for the carbon and nitrogen turnover are carried out by means of both simulated aerated landfills and simulated anaerobic landfills. The results presented in this paper demonstrate that aeration is capable to enhance, both carbon mobilization and discharge via the gas phase. This effect comes along with a significant increase in bio-stabilization of the waste organic fraction, which positively affects the landfill emission behavior in the long run. In terms of leachate pollution reduction it could be demonstrated that the organic load decrease fast and widely independent of the adjusted aeration

  6. Aeration of the teuftal landfill: Field scale concept and lab scale simulation.

    PubMed

    Ritzkowski, Marco; Walker, Beat; Kuchta, Kerstin; Raga, Roberto; Stegmann, Rainer

    2016-09-01

    Long lasting post-closure care (PCC) is often the major financial burden for operators of municipal solid waste (MSW) landfills. Beside costs for the installation and maintenance of technical equipment and barriers, in particular long term treatment of leachate and landfill gas has to be paid from capital surplus. Estimations based on laboratory experiments project time periods of many decades until leachate quality allows for direct discharge (i.e. no need for further purification). Projections based on leachate samples derived from the last 37years for 35 German landfills confirm these assumption. Moreover, the data illustrate that in particular ammonium nitrogen concentrations are likely to fall below limit values only after a period of 300years. In order to avoid long lasting PCC the operator of Teuftal landfill, located in the Swiss canton Bern, decided to biologically stabilize the landfill by means of a combined in situ aeration and moisturization approach. In December 2014 the aeration started at a landfill section containing approximately 30% of the total landfill volume. From summer 2016 onwards the remaining part of the landfill will be aerated. Landfill aeration through horizontal gas and leachate drains is carried out for the first time in field scale in Europe. The technical concept is described in the paper. Parallel to field scale aeration, investigations for the carbon and nitrogen turnover are carried out by means of both simulated aerated landfills and simulated anaerobic landfills. The results presented in this paper demonstrate that aeration is capable to enhance, both carbon mobilization and discharge via the gas phase. This effect comes along with a significant increase in bio-stabilization of the waste organic fraction, which positively affects the landfill emission behavior in the long run. In terms of leachate pollution reduction it could be demonstrated that the organic load decrease fast and widely independent of the adjusted aeration

  7. Effects of shielding gas composition on arc profile and molten pool dynamics in gas metal arc welding of steels

    NASA Astrophysics Data System (ADS)

    Wang, L. L.; Lu, F. G.; Wang, H. P.; Murphy, A. B.; Tang, X. H.

    2014-11-01

    In gas metal arc welding, gases of different compositions are used to produce an arc plasma, which heats and melts the workpiece. They also protect the workpiece from the influence of the air during the welding process. This paper models gas metal arc welding (GMAW) processes using an in-house simulation code. It investigates the effects of the gas composition on the temperature distribution in the arc and on the molten pool dynamics in gas metal arc welding of steels. Pure argon, pure CO2 and different mixtures of argon and CO2 are considered in the study. The model is validated by comparing the calculated weld profiles with physical weld measurements. The numerical calculations reveal that gas composition greatly affects the arc temperature profile, heat transfer to the workpiece, and consequently the weld dimension. As the CO2 content in the shielding gas increases, a more constricted arc plasma with higher energy density is generated as a result of the increased current density in the arc centre and increased Lorentz force. The calculation also shows that the heat transferred from the arc to the workpiece increases with increasing CO2 content, resulting in a wider and deeper weld pool and decreased reinforcement height.

  8. Phytoremediation of landfill leachate

    SciTech Connect

    Jones, D.L. . E-mail: d.jones@bangor.ac.uk; Williamson, K.L.; Owen, A.G.

    2006-07-01

    Leachate emissions from landfill sites are of concern, primarily due to their toxic impact when released unchecked into the environment, and the potential for landfill sites to generate leachate for many hundreds of years following closure. Consequently, economically and environmentally sustainable disposal options are a priority in waste management. One potential option is the use of soil-plant based remediation schemes. In many cases, using either trees (including short rotation coppice) or grassland, phytoremediation of leachate has been successful. However, there are a significant number of examples where phytoremediation has failed. Typically, this failure can be ascribed to excessive leachate application and poor management due to a fundamental lack of understanding of the plant-soil system. On balance, with careful management, phytoremediation can be viewed as a sustainable, cost effective and environmentally sound option which is capable of treating 250 m{sup 3} ha{sup -1} yr{sup -1}. However, these schemes have a requirement for large land areas and must be capable of responding to changes in leachate quality and quantity, problems of scheme establishment and maintenance, continual environmental monitoring and seasonal patterns of plant growth. Although the fundamental underpinning science is well understood, further work is required to create long-term predictive remediation models, full environmental impact assessments, a complete life-cycle analysis and economic analyses for a wide range of landfill scenarios.

  9. Landfills in karst terrains

    SciTech Connect

    Hughes, T.H. ); Memon, B.A.; LaMoreaux, P.E. )

    1994-06-01

    State and Federal regulations have established restrictions for location of hazardous waste and municipal, solid waste landfills. Regulations require owners/operators to demonstrate that the hydrogeology has been completely characterized at proposed landfills, and that locations for monitoring wells have been properly selected. Owners/operators are also required to demonstrate that engineering measures have been incorporated in the design of the municipal solid waste landfills, so that the site is not subject to destabilizing events, as a result of location in unstable areas, such as karst terrains. Karst terrains are typically underlain by limestone or dolomite, and may contain a broad continuum of karst features and karst activity. Preliminary investigation of candidate sites will allow ranking of the sites, rejection of some unsuitable sites, and selection of a few sites for additional studies. The complexity of hydrogeologic systems, in karst terrains, mandates thorough hydrogeologic studies to determine whether a specific site is, or can be rendered, suitable for a land disposal facility. Important components of hydrogeologic studies are: field mapping of structural and stratigraphic units; interpretation of sequential aerial photographs; test drilling and geophysical analyses; fracture analyses; seasonal variation in water-levels; spatial variation of hydraulic characteristics of the aquifer and aquiclude; velocity and direction of movement of ground water within aquifers; determination of control for recharge, discharge, and local base level; and evaluation of the effects of man's activities, such as pumping, dewatering and construction.

  10. Brownfields and health risks--air dispersion modeling and health risk assessment at landfill redevelopment sites.

    PubMed

    Ofungwu, Joseph; Eget, Steven

    2006-07-01

    Redevelopment of landfill sites in the New Jersey-New York metropolitan area for recreational (golf courses), commercial, and even residential purposes seems to be gaining acceptance among municipal planners and developers. Landfill gas generation, which includes methane and potentially toxic nonmethane compounds usually continues long after closure of the landfill exercise phase. It is therefore prudent to evaluate potential health risks associated with exposure to gas emissions before redevelopment of the landfill sites as recreational, commercial, and, especially, residential properties. Unacceptably high health risks would call for risk management measures such as limiting the development to commercial/recreational rather than residential uses, stringent gas control mechanisms, interior air filtration, etc. A methodology is presented for applying existing models to estimate residual landfill hazardous compounds emissions and to quantify associated health risks. Besides the toxic gas constituents of landfill emissions, other risk-related issues concerning buried waste, landfill leachate, and explosive gases were qualitatively evaluated. Five contiguously located landfill sites in New Jersey intended for residential and recreational redevelopment were used to exemplify the approach.

  11. Gas and condensate composition in the deep Tuscaloosa trend, southern Louisiana - influence of oil and wet gas cracking

    SciTech Connect

    Claypool, G.E.; Rooney, M.A.; Vuletich, A.K. )

    1996-01-01

    Natural gas and condensate samples from 34 wells in six fields producing from deep Tuscaloosa sandstones show regular changes in chemical and isotopic composition with increasing depth of burial. A gas-condensate system at 5.2 km (17,000 ft) changes to dry gas at 6.1 km (20,500 ft). Carbon isotopic compositions of ethane and propane become heavier ([delta] [sup 13]C[sub 2] increases from -31 to -23 permil); ([delta][sup 13]C[sub 3] increases from -29 to -21 permil), while methane becomes lighter ([delta][sup 13]C[sub 1] decreases from -38 to -42 permil). Depletion of condensate liquids relative to gas over this same depth interval (condensate/gas ratios decrease from 120 to 1 bbl/mmcf) is accompanied by systematic molecular and isotopic changes in the residual liquids. Higher molecular-weight (>C[sub 20]) hydrocarbons are progressively depleted, and isoprenoids are lost relative to adjacent normal alkanes. The liquids shift to heavier [delta][sup 13]C values (from -27 to -23 permil). These changes are believed to be caused by thermal cracking and progressive conversion of oil and wet gas hydrocarbons to dry gas in Tuscaloosa reservoirs at temperatures of 165 to 195[degrees]C.

  12. [Physical and chemical properties of land-filling pile and aged refuse in 5-year-old semi-aerobic and anaerobic landfills].

    PubMed

    Zhang, Wei; Yue, Bo; Huang, Qi-Fei; Huang, Ze-Chun; Zhang, Zeng-Qiang; Wang, Qi; Lin, Ye; Wang, Jin-An

    2010-03-01

    This paper studied the surface settlement, temperature, and gas production of land-filling pile, and the physical and chemical properties of aged refuse in 5-year-old semi-aerobic and anaerobic landfills. The pile's surface settlement and its volume reduction rate were significantly higher in semi-aerobic than in anaerobic landfill; and the treatment with leachate recycling brought larger uneven settlement than the treatment with water recycling. The temperature of anaerobic landfill pile (25.6 degrees C) was slightly higher than that of semi-aerobic landfill file (24.8 degrees C), but the difference was not significant. During land-filling period, the O2 concentration in semi-aerobic landfill pile was significantly higher than that in anaerobic one, while the CH4 concentration was in reverse. After 5 years land-filling, the contents of easily degradable organic matters in aged refuse, such as kitchen refuses and papers, decreased dramatically, while the contents of plastics, glasses, bricks, and woods increased. In addition, the contents of organic matters and nutrients in aged refuse were higher than those in typical southern China soils, and the concentrations of heavy metals except chromium in anaerobic landfill aged refuse were not beyond the grade three of Environmental Quality Standards for Soils (GB 15618-1995).

  13. Gas storage cylinder formed from a composition containing thermally exfoliated graphite

    NASA Technical Reports Server (NTRS)

    Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor)

    2012-01-01

    A gas storage cylinder or gas storage cylinder liner, formed from a polymer composite, containing at least one polymer and a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m(exp 2)/g to 2600 m(exp 2)2/g.

  14. Use of high temperature insulation for ceramic matrix composites in gas turbines

    DOEpatents

    Morrison, Jay Alan; Merrill, Gary Brian; Ludeman, Evan McNeil; Lane, Jay Edgar

    2001-01-01

    A ceramic composition for insulating components, made of ceramic matrix composites, of gas turbines is provided. The composition comprises a plurality of hollow oxide-based spheres of various dimensions, a phosphate binder, and at least one oxide filler powder, whereby the phosphate binder partially fills gaps between the spheres and the filler powders. The spheres are situated in the phosphate binder and the filler powders such that each sphere is in contact with at least one other sphere and the arrangement of spheres is such that the composition is dimensionally stable and chemically stable at a temperature of approximately 1600.degree. C. A stationary vane of a gas turbine comprising the composition of the present invention bonded to the outer surface of the vane is provided. A combustor comprising the composition bonded to the inner surface of the combustor is provided. A transition duct comprising the insulating coating bonded to the inner surface of the transition is provided. Because of abradable properties of the composition, a gas turbine blade tip seal comprising the composition also is provided. The composition is bonded to the inside surface of a shroud so that a blade tip carves grooves in the composition so as to create a customized seal for the turbine blade tip.

  15. The influence of atmospheric pressure on landfill methane emissions

    SciTech Connect

    Czepiel, P.M.; Shorter, J.H.; Mosher, B.; Allwine, E.; McManus, J.B.; Harriss, R.C.; Kolb, C.E.; Lamb, B.K

    2003-07-01

    Landfills are the largest source of anthropogenic methane (CH{sub 4}) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH{sub 4} emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH{sub 4} emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m{sup 3} CH{sub 4} min{sup -1}. A simple regression model of our results was used to calculate an annual emission rate of 8.4x10{sup 6} m{sup 3} CH{sub 4} year{sup -1}. These data, along with CH{sub 4} oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH{sub 4} generation at this landfill. A reported gas collection rate of 7.1x10{sup 6} m{sup 3} CH{sub 4} year{sup -1} and an estimated annual rate of CH{sub 4} oxidation by cover soils of 1.2x10{sup 6} m{sup 3} CH{sub 4} year{sup -1} resulted in a calculated annual CH{sub 4} generation rate of 16.7x10{sup 6} m{sup 3} CH{sub 4} year{sup -1}. These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential.

  16. [Research advances in control of N2O emission from municipal solid waste landfill sites].

    PubMed

    Cai, Chuan-Yu; Li, Bo; Lü, Hao-Hao; Wu, Wei-Xiang

    2012-05-01

    Landfill is one of the main approaches for municipal solid waste treatment, and landfill site is a main emission source of greenhouse gases nitrous oxide (N2O) and methane (CH4). As a high-efficient trace greenhouse gas, N2O has a very high warming potential, with a warming capacity 296 times of CO2, and has a long-term stability in atmosphere, giving greater damage to the ozone layer. Aiming at the researches in the control of N2O emission from municipal solid waste landfill sites, this paper summarized the characteristics and related affecting factors of the N2O emission from the landfill sites, and put forward a series of the measures adaptable to the N2O emission control of present municipal solid waste landfill sites in China. Some further research focuses on the control of N2O emission from the landfill sites were also presented.

  17. Air emissions assessment and air quality permitting for a municipal waste landfill treating municipal sewage sludge

    SciTech Connect

    Koehler, J.

    1998-12-31

    This paper presents a case study into the air quality permitting of a municipal solid waste (MSW) landfill in the San Francisco Bay Area undergoing a proposed expansion in operations to increase the life of the landfill. The operations of this facility include MSW landfilling, the treatment and disposal of municipal sewage sludge, the aeration of petroleum-contaminated soils, the construction of a new on-site plant to manufacture soil amendment products from waste wood and other organic material diverted from the landfill, and the installation of a vaporator to create steam from leachate for injection into the landfill gas flare. The emissions assessment for each project component relied upon interpretation of source tests from similar operations, incorporation of on-site measurements into emissions models and mass balances, and use of AP-42 procedures for emissions sources such as wind-blown dust, material handling and transfer operations, and fugitive landfill gas. Air permitting issues included best available control technology (BACT), emission offset thresholds, new source performance standards (NSPS), potential air toxics health risk impacts, and compliance with federal Title V operating permit requirements. With the increasing difficulties of siting new landfills, increasing pressures to reduce the rate of waste placement into existing landfills, and expanding regulatory requirements on landfill operations, experiences similar to those described in this paper are likely to increase in the future as permitting scenarios become more complex.

  18. Closed landfills to solar energy power plants: Estimating the solar potential of closed landfills in California

    NASA Astrophysics Data System (ADS)

    Munsell, Devon R.

    Solar radiation is a promising source of renewable energy because it is abundant and the technologies to harvest it are quickly improving. An ongoing challenge is to find suitable and effective areas to implement solar energy technologies without causing ecological harm. In this regard, one type of land use that has been largely overlooked for siting solar technologies is closed or soon to be closed landfills. Utilizing Geographic Information System (GIS) based solar modeling; this study makes an inventory of solar generation potential for such sites in the state of California. The study takes account of various site characteristics in relation to the siting needs of photovoltaic (PV) geomembrane and dish-Stirling technologies (e.g., size, topography, closing date, solar insolation, presence of landfill gas recovery projects, and proximity to transmission grids and roads). This study reaches the three principal conclusions. First, with an estimated annual solar electricity generation potential of 3.7 million megawatt hours (MWh), closed or soon to be closed landfill sites could provide an amount of power significantly larger than California's current solar electric generation. Secondly, the possibility of combining PV geomembrane, dish-Stirling, and landfill gas (LFG) to energy technologies at particular sites deserves further investigation. Lastly, there are many assumptions, challenges, and limitations in conducting inventory studies of solar potential for specific sites, including the difficulty in finding accurate data regarding the location and attributes of potential landfills to be analyzed in the study. Furthermore, solar modeling necessarily simplifies a complex phenomenon, namely incoming solar radiation. Additionally, site visits, while necessary for finding details of the site, are largely impractical for a large scale study.

  19. Compositional Discrimination of Decompression and Decomposition Gas Bubbles in Bycaught Seals and Dolphins

    PubMed Central

    Bernaldo de Quirós, Yara; Seewald, Jeffrey S.; Sylva, Sean P.; Greer, Bill; Niemeyer, Misty; Bogomolni, Andrea L.; Moore, Michael J.

    2013-01-01

    Gas bubbles in marine mammals entangled and drowned in gillnets have been previously described by computed tomography, gross examination and histopathology. The absence of bacteria or autolytic changes in the tissues of those animals suggested that the gas was produced peri- or post-mortem by a fast decompression, probably by quickly hauling animals entangled in the net at depth to the surface. Gas composition analysis and gas scoring are two new diagnostic tools available to distinguish gas embolisms from putrefaction gases. With this goal, these methods have been successfully applied to pathological studies of marine mammals. In this study, we characterized the flux and composition of the gas bubbles from bycaught marine mammals in anchored sink gillnets and bottom otter trawls. We compared these data with marine mammals stranded on Cape Cod, MA, USA. Fresh animals or with moderate decomposition (decomposition scores of 2 and 3) were prioritized. Results showed that bycaught animals presented with significantly higher gas scores than stranded animals. Gas composition analyses indicate that gas was formed by decompression, confirming the decompression hypothesis. PMID:24367623

  20. Compositional discrimination of decompression and decomposition gas bubbles in bycaught seals and dolphins.

    PubMed

    Bernaldo de Quirós, Yara; Seewald, Jeffrey S; Sylva, Sean P; Greer, Bill; Niemeyer, Misty; Bogomolni, Andrea L; Moore, Michael J

    2013-01-01

    Gas bubbles in marine mammals entangled and drowned in gillnets have been previously described by computed tomography, gross examination and histopathology. The absence of bacteria or autolytic changes in the tissues of those animals suggested that the gas was produced peri- or post-mortem by a fast decompression, probably by quickly hauling animals entangled in the net at depth to the surface. Gas composition analysis and gas scoring are two new diagnostic tools available to distinguish gas embolisms from putrefaction gases. With this goal, these methods have been successfully applied to pathological studies of marine mammals. In this study, we characterized the flux and composition of the gas bubbles from bycaught marine mammals in anchored sink gillnets and bottom otter trawls. We compared these data with marine mammals stranded on Cape Cod, MA, USA. Fresh animals or with moderate decomposition (decomposition scores of 2 and 3) were prioritized. Results showed that bycaught animals presented with significantly higher gas scores than stranded animals. Gas composition analyses indicate that gas was formed by decompression, confirming the decompression hypothesis. PMID:24367623

  1. A molecular survey of outflow gas: velocity-dependent shock chemistry and the peculiar composition of the EHV gas

    NASA Astrophysics Data System (ADS)

    Tafalla, M.; Santiago-García, J.; Hacar, A.; Bachiller, R.

    2010-11-01

    Context. Bipolar outflows from Class 0 protostars often present two components in their CO spectra that have different kinematic behaviors: a smooth outflow wing and a discrete, extremely high-velocity (EHV) peak. Aims: To better understand the origin of these two outflow components, we have studied and compared their molecular composition. Methods: We carried out a molecular survey of the outflows powered by L1448-mm and IRAS 04166+2706, two sources with prominent wing and EHV components. For each source, we observed a number of molecular lines towards the brightest outflow position and used them to determine column densities for 12 different molecular species. Results: The molecular composition of the two outflows is very similar. It presents systematic changes with velocity that we analyze by dividing the outflow in three chemical regimes, two of them associated with the wing component and the other the EHV gas. The analysis of the two wing regimes shows that species like H2CO and CH3OH favor the low-velocity gas, while SiO and HCN are more abundant in the fastest gas. This fastest wing gas presents strong similarities with the composition of the “chemically active” L1157 outflow (whose abundances we re-evaluate in an appendix). We find that the EHV regime is relatively rich in O-bearing species compared to the wing regime. The EHV gas is not only detected in CO and SiO (already reported elsewhere), but also in SO, CH3OH, and H2CO (newly reported here), with a tentative detection in HCO+. At the same time, the EHV regime is relatively poor in C-bearing molecules like CS and HCN, for which we only obtain weak detections or upper limits despite deep integrations. We suggest that this difference in composition arises from a lower C/O ratio in the EHV gas. Conclusions: The different chemical compositions of the wing and EHV regimes suggest that these two outflow components have different physical origins. The wing component is better explained by shocked ambient

  2. Decolorization of landfill leachate using electrochemical oxidation technique

    NASA Astrophysics Data System (ADS)

    Jumaah, Majd Ahmed; Othman, Mohamed Rozali

    2015-09-01

    The study was carried out to investigate the electrochemical oxidation of landfill leachate from the Jeram sanitary landfill leachate using charcoal base metallic composite electrodes. The control parameters used were applied voltage, Cl- concentration (as supporting electrolyte) and pH of the solution. The optimum conditions obtained were NaCl concentration of 1.5 % (w/v), applied voltage of 10 V, operating time 180 min and C60CG Co10PVC15 electrode as an anode.15 Electrochemical treatment using charcoal base metallic composite electrode was able to remove color up to 79%.

  3. Method and apparatus for real-time measurement of fuel gas compositions and heating values

    DOEpatents

    Zelepouga, Serguei; Pratapas, John M.; Saveliev, Alexei V.; Jangale, Vilas V.

    2016-03-22

    An exemplary embodiment can be an apparatus for real-time, in situ measurement of gas compositions and heating values. The apparatus includes a near infrared sensor for measuring concentrations of hydrocarbons and carbon dioxide, a mid infrared sensor for measuring concentrations of carbon monoxide and a semiconductor based sensor for measuring concentrations of hydrogen gas. A data processor having a computer program for reducing the effects of cross-sensitivities of the sensors to components other than target components of the sensors is also included. Also provided are corresponding or associated methods for real-time, in situ determination of a composition and heating value of a fuel gas.

  4. A robust method for estimating landfill methane emissions.

    PubMed

    Figueroa, Veronica K; Mackie, Kevin R; Guarriello, Nick; Cooper, C David

    2009-08-01

    Because municipal solid waste (MSW) landfills emit significant amounts of methane, a potent greenhouse gas, there is considerable interest in quantifying surficial methane emissions from landfills. The authors present a method to estimate methane emissions, using ambient air volatile organic compound (VOC) measurements taken above the surface of the landfill. Using a hand-held monitor, hundreds of VOC concentrations can be taken easily in a day, and simple meteorological data can be recorded at the same time. The standard Gaussian dispersion equations are inverted and solved by matrix methods to determine the methane emission rates at hundreds of point locations throughout a MSW landfill. These point emission rates are then summed to give the total landfill emission rate. This method is tested on a central Florida MSW landfill using data from 3 different days, taken 6 and 12 months apart. A sensitivity study is conducted, and the emission estimates are most sensitive to the input meteorological parameters of wind speed and stability class. Because of the many measurements that are used, the results are robust. When the emission estimates were used as inputs into a dispersion model, a reasonable scatterplot fit of the individual concentration measurement data resulted. PMID:19728486

  5. Site-specific criteria for the completion of landfill aftercare.

    PubMed

    Laner, David; Fellner, Johann; Brunner, Paul H

    2012-09-01

    Municipal solid waste (MSW) landfills need to be managed after closure to assure long-term environmental compatibility. Aftercare can be completed when the authorities consider the landfill not likely to pose a threat to humans and the environment. In this work, a methodology for deriving site-specific aftercare completion criteria is presented and its application is illustrated via a case study. The evaluation method combines models addressing waste emission behavior, long-term barrier performance, and pollutant migration to assess the potential impact of landfill emissions on the environment. Based on the definition of acceptable impact levels at certain points of compliance, scenario- and pollutant-specific aftercare completion criteria are derived. The methodology was applied to a closed MSW landfill in Austria and potential aftercare durations were determined. While landfill gas emissions may become environmentally tolerable within decades at the site, leachate-related aftercare measures were expected to be necessary for centuries (primarily as a result of ammonium). Although the evaluation comes with large uncertainties, it allows for linking aftercare intensity and duration with respect to an environmentally compatible state of the landfill in the absence of aftercare. However, further case studies including regulatory review and acceptance are needed to use the methodology in a decision support tool on aftercare completion.

  6. A finite element simulation of biological conversion processes in landfills

    SciTech Connect

    Robeck, M.; Ricken, T.

    2011-04-15

    Landfills are the most common way of waste disposal worldwide. Biological processes convert the organic material into an environmentally harmful landfill gas, which has an impact on the greenhouse effect. After the depositing of waste has been stopped, current conversion processes continue and emissions last for several decades and even up to 100 years and longer. A good prediction of these processes is of high importance for landfill operators as well as for authorities, but suitable models for a realistic description of landfill processes are rather poor. In order to take the strong coupled conversion processes into account, a constitutive three-dimensional model based on the multiphase Theory of Porous Media (TPM) has been developed at the University of Duisburg-Essen. The theoretical formulations are implemented in the finite element code FEAP. With the presented calculation concept we are able to simulate the coupled processes that occur in an actual landfill. The model's theoretical background and the results of the simulations as well as the meantime successfully performed simulation of a real landfill body will be shown in the following.

  7. Precipitates in landfill leachate mediated by dissolved organic matters.

    PubMed

    Li, Zhenze; Xue, Qiang; Liu, Lei; Li, Jiangshan

    2015-04-28

    Clogging of landfill leachate collection system is so ubiquitous that it causes problems to landfills. Although precipitations of calcite and other minerals have been widely observed, the mechanism of precipitation remains obscure. We examined the clog composition, dissolved organic matters, leachate chemical compositions and the correlation of these variables in view of the precipitation process. It is shown that Dissolved Organic Carbon (DOC) inhibits precipitation of landfill leachate. Using the advanced NICA-Donnan model, the analysis of aqueous chemical reactions between Mg-Ca-DOC-CO2 suggests a good agreement with experimental observations. Calcite and dolomite are both found to be oversaturated in most of the landfill leachate samples. DOC is found to preferentially bind with Mg than Ca, leading to more likely precipitation of Calcite than dolomite from landfill leachate. The NICA-Donnan model gives a reasonable estimation of dolomite saturation index in a wide range of DOC. Modeling confirms the major precipitation mechanism in terms of alkaline earth metal carbonate. Uncertainties in model parameters are discussed with particular focus on DOC composition, functional group types and density concentration and the influential factors. PMID:25661175

  8. Precipitates in landfill leachate mediated by dissolved organic matters.

    PubMed

    Li, Zhenze; Xue, Qiang; Liu, Lei; Li, Jiangshan

    2015-04-28

    Clogging of landfill leachate collection system is so ubiquitous that it causes problems to landfills. Although precipitations of calcite and other minerals have been widely observed, the mechanism of precipitation remains obscure. We examined the clog composition, dissolved organic matters, leachate chemical compositions and the correlation of these variables in view of the precipitation process. It is shown that Dissolved Organic Carbon (DOC) inhibits precipitation of landfill leachate. Using the advanced NICA-Donnan model, the analysis of aqueous chemical reactions between Mg-Ca-DOC-CO2 suggests a good agreement with experimental observations. Calcite and dolomite are both found to be oversaturated in most of the landfill leachate samples. DOC is found to preferentially bind with Mg than Ca, leading to more likely precipitation of Calcite than dolomite from landfill leachate. The NICA-Donnan model gives a reasonable estimation of dolomite saturation index in a wide range of DOC. Modeling confirms the major precipitation mechanism in terms of alkaline earth metal carbonate. Uncertainties in model parameters are discussed with particular focus on DOC composition, functional group types and density concentration and the influential factors.

  9. Ammonia gas sensing behavior of tanninsulfonic acid doped polyaniline-TiO₂ composite.

    PubMed

    Bairi, Venu Gopal; Bourdo, Shawn E; Sacre, Nicolas; Nair, Dev; Berry, Brian C; Biris, Alexandru S; Viswanathan, Tito

    2015-10-16

    A highly active tannin doped polyaniline-TiO₂ composite ammonia gas sensor was developed and the mechanism behind the gas sensing activity was reported for the first time. A tanninsulfonic acid doped polyaniline (TANIPANI)-titanium dioxide nanocomposite was synthesized by an in situ polymerization of aniline in the presence of tanninsulfonic acid and titanium dioxide nanoparticles. X-ray diffraction and thermogravimetric analysis were utilized to determine the incorporation of TiO₂ in TANIPANI matrix. UV-Visible and infrared spectroscopy studies provided information about the electronic interactions among tannin, polyaniline, and TiO₂. Scanning electron microscopy (SEM) along with energy dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM) surface analysis techniques were used to investigate the metal oxide dispersions inside polyaniline matrix. Gas sensors were prepared by spin coating solutions of TANIPANI-TiO₂ and TANIPANI composites onto glass slides. Sensors were tested at three different concentrations (20 ppm, 40 ppm, and 60 ppm) of ammonia gas at ambient temperature conditions by measuring the changes in surface resistivity of the films with respect to time. Ammonia gas sensing plots are presented showing the response values, response times and recovery times. The TANIPANI-TiO₂ composite exhibited better response and shorter recovery times when compared to TANIPANI control and other polyaniline composites that have been reported in the literature. For the first time a proposed mechanism of gas sensing basing on the polaron band localization and its effects on the gas sensing behavior of polyaniline are reported.

  10. Gas sensors based on carbon nanoflake/tin oxide composites for ammonia detection.

    PubMed

    Lee, Soo-Keun; Chang, Daeic; Kim, Sang Wook

    2014-03-15

    Carbon nanoflake (CNFL) was obtained from graphite pencil by using the electrochemical method and the CNFL/SnO2 composite material assessed its potential as an ammonia gas sensor. A thin film resistive gas sensor using the composite material was manufactured by the drop casting method, and the sensor was evaluated to test in various ammonia concentrations and operating temperatures. Physical and chemical characteristics of the composite material were assessed using SEM, TEM, SAED, EDS and Raman spectroscopy. The composite material having 10% of SnO2 showed 3 times higher sensor response and better repeatability than the gas sensor using pristine SnO2 nano-particle at the optimal temperature of 350°C.

  11. Gas sensors based on carbon nanoflake/tin oxide composites for ammonia detection.

    PubMed

    Lee, Soo-Keun; Chang, Daeic; Kim, Sang Wook

    2014-03-15

    Carbon nanoflake (CNFL) was obtained from graphite pencil by using the electrochemical method and the CNFL/SnO2 composite material assessed its potential as an ammonia gas sensor. A thin film resistive gas sensor using the composite material was manufactured by the drop casting method, and the sensor was evaluated to test in various ammonia concentrations and operating temperatures. Physical and chemical characteristics of the composite material were assessed using SEM, TEM, SAED, EDS and Raman spectroscopy. The composite material having 10% of SnO2 showed 3 times higher sensor response and better repeatability than the gas sensor using pristine SnO2 nano-particle at the optimal temperature of 350°C. PMID:24473403

  12. NOVEL COMPOSITE MEMBRANES AND PROCESS FOR NATURAL GAS UPGRADING

    SciTech Connect

    Ben Bikson; Sal Giglia; Jibin Hao

    2003-03-01

    In the second phase of this project, the newly developed membrane module for natural gas dehydration was tested and evaluated in a pilot plant located at a commercial natural gas treatment site. This phase was undertaken jointly with UOP LLC, our commercialization partner. The field test demonstrated that a commercial-size membrane module for natural gas dehydration was successfully manufactured. The membrane module operated reliably over 1000 psi differential pressure across the membrane in the field test. The effects of feed gas pressure, permeate gas pressure, feed flow rate, purge ratio (flow rate ratio of permeate outlet to feed), and feed gas dew point on the membrane module performance were determined and found to meet the design expectations. Although water vapor permeance was lower than expected, substantial natural gas dehydration was demonstrated with low purge ratio. For example, dew point was suppressed by as much as 30 F with only about 2 {approx} 3% purge ratio. However the bore side pressure drops were significantly higher than the projected value from the fluid dynamic calculation. It is likely that not all the fibers were open in either the sweep or the permeate tube sheet end. This could help to explain the relatively low water vapor permeances that were measured in the field. An economic evaluation of the membrane process and the traditional Triethylene Glycol (TEG) process to dehydrate natural gas was performed and the economics of the two processes were compared. Two sets of membrane module performance properties were used in the economic analysis of the membrane process. One was from the results of this field test and the other from the results of the previous small-scale test with a medium pressure membrane variant conducted at 750 psig. The membrane process was competitive with the TEG process for the natural gas feed flow rate below 10 MMSCFD for the membrane with previously measured water vapor permeance. The membrane process was

  13. Biogeochemical transformations of mercury in solid waste landfills and pathways for release.

    PubMed

    Lee, Sung-Woo; Lowry, Gregory V; Hsu-Kim, Heileen

    2016-02-01

    Mercury (Hg) is present in a variety of solid wastes including industrial wastes, household products, consumer electronics, and medical wastes, some of which can be disposed in conventional landfills. The presence of this neurotoxic metal in landfills is a concern due to the potential for it to leach or volatilize from the landfill and impact local ecosystems. The objective of this review is to describe general practices for the disposal of mercury-bearing solid wastes, summarize previous studies on the release of mercury from landfills, and delineate the expected transformations of Hg within landfill environments that would influence transport of Hg via landfill gas and leachate. A few studies have documented the emissions of Hg as landfill gas, primarily as gaseous elemental Hg(0) and smaller amounts as methylated Hg species. Much less is known regarding the release of Hg in leachate. Landfill conditions are unique from other subsurface environments in that they can contain water with very high conductivity and organic carbon concentration. Landfills also experience large changes in redox potential (and the associated microbial community) that greatly influence Hg speciation, transformations, and mobilization potential. Generally, Hg is not likely to persist in large quantities as dissolved species, since Hg(0) tends to evolve in the gas phase and divalent Hg(ii) sorbs strongly to particulate phases including organic carbon and sulfides. However, Hg(ii) has the potential to associate with or form colloidal particles that can be mobilized in porous media under high organic carbon conditions. Moreover, the anaerobic conditions within landfills can foster the growth of microorganisms that produced monomethyl- and dimethyl-Hg species, the forms of mercury with high potential for bioaccumulation. Much advancement has recently been made in the mercury biogeochemistry research field, and this study seeks to incorporate these findings for landfill settings.

  14. Biogeochemical transformations of mercury in solid waste landfills and pathways for release.

    PubMed

    Lee, Sung-Woo; Lowry, Gregory V; Hsu-Kim, Heileen

    2016-02-01

    Mercury (Hg) is present in a variety of solid wastes including industrial wastes, household products, consumer electronics, and medical wastes, some of which can be disposed in conventional landfills. The presence of this neurotoxic metal in landfills is a concern due to the potential for it to leach or volatilize from the landfill and impact local ecosystems. The objective of this review is to describe general practices for the disposal of mercury-bearing solid wastes, summarize previous studies on the release of mercury from landfills, and delineate the expected transformations of Hg within landfill environments that would influence transport of Hg via landfill gas and leachate. A few studies have documented the emissions of Hg as landfill gas, primarily as gaseous elemental Hg(0) and smaller amounts as methylated Hg species. Much less is known regarding the release of Hg in leachate. Landfill conditions are unique from other subsurface environments in that they can contain water with very high conductivity and organic carbon concentration. Landfills also experience large changes in redox potential (and the associated microbial community) that greatly influence Hg speciation, transformations, and mobilization potential. Generally, Hg is not likely to persist in large quantities as dissolved species, since Hg(0) tends to evolve in the gas phase and divalent Hg(ii) sorbs strongly to particulate phases including organic carbon and sulfides. However, Hg(ii) has the potential to associate with or form colloidal particles that can be mobilized in porous media under high organic carbon conditions. Moreover, the anaerobic conditions within landfills can foster the growth of microorganisms that produced monomethyl- and dimethyl-Hg species, the forms of mercury with high potential for bioaccumulation. Much advancement has recently been made in the mercury biogeochemistry research field, and this study seeks to incorporate these findings for landfill settings. PMID:26745831

  15. Radioactivity and elemental analysis in the Ruseifa municipal landfill, Jordan.

    PubMed

    Al-Jundi, J; Al-Tarazi, E

    2008-01-01

    In this study, a low background gamma-ray spectrometer based on a Hyper Pure Germanium detector was used to determine the activity concentrations of natural radionuclides in soil samples from various locations within the Ruseifa municipal landfill in Jordan. The chemical composition of the samples was also determined using a Wavelength Dispersive X-Ray Fluorescence Spectrometer. The maximum and minimum annual outdoor effective doses were found to be 103 and 36microSva(-1) in the old landfill and Abu-Sayaah village, respectively. The annual outdoor effective dose at the recent landfill site was found to be 91microSva(-1). The annual effective dose equivalents from outdoor terrestrial gamma radiation at the old landfill and the recent landfill were higher than the typical worldwide value of 70microSva(-1). Thus, some remediation of the soils on both old and recent landfills should be considered before any development for public activities. This could be achieved by mixing with clean soil from areas which are known to have lower radiation background. The concentration of heavy metals Zn, Cr, and Ba in the three sites included in this study were found to be higher than the background levels in the soil samples of the control area (Abu-Sayaah village). The enrichment factors for the above three elements were calculated and found to be: complex building site: Zn=2.52 and Ba=1.33; old landfill site: Cr=1.88, Zn=3.64, and Ba=1.26; and recent landfill site: Cr=1.57, Zn=2.19, and Ba=1.28. There was a strong negative correlation between the concentrations of the metallic elements (Mg, Al, Mn, Fe and Rb) and the concentrations of Zn, Ba, and Cr. Moreover, a strong positive correlation was found between Zn, Ba, and Cr. Thus these elements were enriched in the solid waste.

  16. Construction and evaluation of simulated pilot scale landfill lysimeter in Bangladesh.

    PubMed

    Rafizul, Islam M; Howlader, Milon Kanti; Alamgir, Muhammed

    2012-11-01

    This research concentrates the design, construction and evaluation of simulated pilot scale landfill lysimeter at KUET campus, Khulna, Bangladesh. Both the aerobic and anaerobic conditions having a base liner and two different types of cap liner were simulated. After the design of a reference cell, the construction of landfill lysimeter was started in January 2008 and completed in July 2008. In all construction process locally available civil construction materials were used. The municipal solid waste (MSW) of 2800-2985 kg having the total volume of 2.80 m(3) (height 1.6 m) and moisture content of 65% was deposited in each lysimeter by applying required compaction energy. In contrast, both the composition in terms of methane (CH(4)), carbon dioxide (CO(2)) and oxygen (O(2)) as well as the flow rate of landfill gas (LFG) generated from MSW in landfill lysimeter were measured and varied significantly in relation to the variation of lysimeter operational condition. Moreover, anaerobic lysimeter-C shows the highest composition of LFG in compare to the anaerobic lysimeter-B due to the providing of lower compaction of cap liner in anaerobic lysimeter-C. Here, it is interesting to note that in absence of compacted clay liner (CCL) and hence percolation of rainwater that facilitates rapid degradation of MSW in aerobic lysimeter-A has resulted in the highest settlement than that of anaerobic landfill lysimeter-B and C. Moreover, in case of anaerobic lysimeter-B and C, the leachate generation was lower than that of aerobic lysimeter-A due to the providing of cap liner in anaerobic lysimeter-B and C, played an important role to reduce the percolation of rainwater. The study also reveals that the leachate pollution index (LPI) has decreased in relation to the increasing of elapsed period as well as the LPI for collection system of aerobic lysimeter-A was higher than that of the collection system of anaerobic lysimeter-B and C. Finally, it can be depicted that LPI for lysimeter

  17. Using observed data to improve estimated methane collection from select U.S. landfills.

    PubMed

    Wang, Xiaoming; Nagpure, Ajay S; DeCarolis, Joseph F; Barlaz, Morton A

    2013-04-01

    The anaerobic decomposition of solid waste in a landfill produces methane, a potent greenhouse gas, and if recovered, a valuable energy commodity. Methane generation from U.S. landfills is usually estimated using the U.S. EPA's Landfill Gas Emissions Model (LandGEM). Default values for the two key parameters within LandGEM, the first-order decay rate (k) and the methane production potential (L0) are based on data collected in the 1990s. In this study, observed methane collection data from 11 U.S. landfills and estimates of gas collection efficiencies developed from site-specific gas well installation data were included in a reformulated LandGEM equation. Formal search techniques were employed to optimize k for each landfill to find the minimum sum of squared errors (SSE) between the LandGEM prediction and the observed collection data. Across nearly all landfills, the optimal k was found to be higher than the default AP-42 of 0.04 yr(-1) and the weighted average decay for the 11 landfills was 0.09 - 0.12 yr(-1). The results suggest that the default k value assumed in LandGEM is likely too low, which implies that more methane is produced in the early years following waste burial when gas collection efficiencies tend to be lower.

  18. Changing face of the landfill

    SciTech Connect

    1995-10-01

    Integrated approach at Oregon landfill diverts wood and yard trimmings, while turning methane into power for 1,800 homes. Opened in the 1940`s as an open burn dump, Coffin Butte has evolved over the years into a sophisticated waste management facility incorporating ambitious recovery programs. While some of this change has been driven by regulatory demands, many of Valley Landfill`s innovations have come in response to market opportunities. Valley Landfill`s Processing and Recovery Center (PRC) is located a half mile down the road from the landfill site. Opened in 1990, the facility recycles urban wood waste, yard trimmings and street sweepings. The heart of this operation is a 500 hp horizontal feed, fixed-hammer grinder. Although this machine is typically used only for wood grinding, PRC was able to adapt it to handle both wood and yard trimmings by installing special feed roll assembly to compress green waste passing over the infeed belt. The facility handles approximately 40,000 cubic yards of loose green material and produces 15,000 to 18,000 yards of compost. The finished product is run through a trommel with a 5/8 inch mesh screen. Most of the compost is sold in bulk to area garden centers. A portion is processed through a 3/8 inch shaker screen and sold to a local company for use in bagged soil products. Valley Landfill is a partner in an ambitious project to generate electricity from landfill biogas.

  19. Stabilizing Waste Materials for Landfills

    ERIC Educational Resources Information Center

    Environmental Science and Technology, 1977

    1977-01-01

    The test procedures used to evaluate the suitability of landfilled materials of varying stability and to determine the leachate from such materials are reviewed. A process for stabilizing a mixture of sulfur dioxide sludge, fly ash, and bottom ash with lime and other additives for deposition in landfills is detailed. (BT)

  20. Specific model for the estimation of methane emission from municipal solid waste landfills in India.

    PubMed

    Kumar, Sunil; Nimchuk, Nick; Kumar, Rakesh; Zietsman, Josias; Ramani, Tara; Spiegelman, Clifford; Kenney, Megan

    2016-09-01

    The landfill gas (LFG) model is a tool for measuring methane (CH4) generation rates and total CH4 emissions from a particular landfill. These models also have various applications including the sizing of the LFG collection system, evaluating the benefits of gas recovery projects, and measuring and controlling gaseous emissions. This research paper describes the development of a landfill model designed specifically for Indian climatic conditions and the landfill's waste characteristics. CH4, carbon dioxide (CO2), oxygen (O2) and temperature were considered as the prime factor for the development of this model. The developed model was validated for three landfill sites in India: Shillong, Kolkata, and Jaipur. The autocorrelation coefficient for the model was 0.915, while the R(2) value was 0.429. PMID:27343450

  1. Reactant gas composition for fuel cell potential control

    DOEpatents

    Bushnell, Calvin L.; Davis, Christopher L.

    1991-01-01

    A fuel cell (10) system in which a nitrogen (N.sub.2) gas is used on the anode section (11) and a nitrogen/oxygen (N.sub.2 /O.sub.2) gaseous mix is used on the cathode section (12) to maintain the cathode at an acceptable voltage potential during adverse conditions occurring particularly during off-power conditions, for example, during power plant shutdown, start-up and hot holds. During power plant shutdown, the cathode section is purged with a gaseous mixture of, for example, one-half percent (0.5%) oxygen (O.sub.2) and ninety-nine and a half percent (99.5%) nitrogen (N.sub.2) supplied from an ejector (21) bleeding in air (24/28) into a high pressure stream (27) of nitrogen (N.sub.2) as the primary or majority gas. Thereafter the fuel gas in the fuel processor (31) and the anode section (11) is purged with nitrogen gas to prevent nickel (Ni) carbonyl from forming from the shift catalyst. A switched dummy electrical load (30) is used to bring the cathode potential down rapidly during the start of the purges. The 0.5%/99.5% O.sub.2 /N.sub.2 mixture maintains the cathode potential between 0.3 and 0.7 volts, and this is sufficient to maintain the cathode potential at 0.3 volts for the case of H.sub.2 diffusing to the cathode through a 2 mil thick electrolyte filled matrix and below 0.8 volts for no diffusion at open circuit conditions. The same high pressure gas source (20) is used via a "T" juncture ("T") to purge the anode section and its associated fuel processor (31).

  2. Decomposition of forest products buried in landfills

    SciTech Connect

    Wang, Xiaoming; Padgett, Jennifer M.; Powell, John S.; Barlaz, Morton A.

    2013-11-15

    Highlights: • This study tracked chemical changes of wood and paper in landfills. • A decomposition index was developed to quantify carbohydrate biodegradation. • Newsprint biodegradation as measured here is greater than previous reports. • The field results correlate well with previous laboratory measurements. - Abstract: The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5 yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C + H) loss of up to 38%, while loss for the other wood types was 0–10% in most samples. The C + H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27 g OC g{sup −1} dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than

  3. Constraints on the origins of hydrocarbon gas from compositions of gases at their site of origin

    PubMed

    Price, L C; Schoell, M

    1995-11-23

    It is widely accepted that natural gas is formed from thermal decomposition of both oil in reservoirs and, to a lesser extent, the organic matter in shales from which the oil was derived. But laboratory pyrolysis experiments on shales do not reproduce the methane-rich composition typical of most gas reservoirs, leading to suggestions that other mechanisms, such as transition-metal catalysis, may be important. The discrepancy might, however, instead arise because gas (and oil) deposits have migrated from their source rocks, so that the reservoir composition might not be representative of the composition in the source rocks where the hydrocarbons were generated. To address this question, we have analysed gas samples coproduced with oils directly from a source rock (the Bakken shales, North Dakota, USA) where the local geology has prevented significant hydrocarbon migration. The methane contents of these Bakken-shale gases are much lower than that of conventional gas reservoirs, but are consistent with that from pyrolysis experiments on these shales. Thus, because these Bakken gases form with (rather than from) oils, we argue that compositional differences between gases from source rocks and conventional gas deposits result from fractionation processes occurring after hydrocarbon expulsion from the source rock. PMID:11536709

  4. Constraints on the origins of hydrocarbon gas from compositions of gases at their site of origin

    USGS Publications Warehouse

    Price, L.C.; Schoell, M.

    1995-01-01

    IT is widely accepted that natural gas is formed from thermal decomposition of both oil in reservoirs and, to a lesser extent, the organic matter in shales from which the oil was derived1-6. But laboratory pyrolysis experiments on shales do not reproduce the methane-rich composition typical of most gas reservoirs7, leading to suggestions7 that other mechanisms, such as transition-metal catalysis, may be important. The discrepancy might, however, instead arise because gas (and oil) deposits have migrated from their source rocks, so that the reservoir composition might not be representative of the composition in the source rocks where the hydrocarbons were generated. To address this question, we have analysed gas samples coproduced with oils directly from a source rock (the Bakken shales, North Dakota, USA) where the local geology has prevented significant hydrocarbon migration. The methane contents of these Bakken-shale gases are much lower than that of conventional gas reservoirs, but are consistent with that from pyrolysis experiments8,9 on these shales. Thus, because these Bakken gases form with (rather than from) oils, we argue that compositional differences between gases from source rocks and conventional gas deposits result from fractionation processes occurring after hydrocarbon expulsion from the source rock.

  5. Decompression vs. Decomposition: Distribution, Amount, and Gas Composition of Bubbles in Stranded Marine Mammals

    PubMed Central

    de Quirós, Yara Bernaldo; González-Diaz, Oscar; Arbelo, Manuel; Sierra, Eva; Sacchini, Simona; Fernández, Antonio

    2012-01-01

    Gas embolic lesions linked to military sonar have been described in stranded cetaceans including beaked whales. These descriptions suggest that gas bubbles in marine mammal tissues may be more common than previously thought. In this study we have analyzed gas amount (by gas score) and gas composition within different decomposition codes using a standardized methodology. This broad study has allowed us to explore species-specific variability in bubble prevalence, amount, distribution, and composition, as well as masking of bubble content by putrefaction gases. Bubbles detected within the cardiovascular system and other tissues related to both pre- and port-mortem processes are a common finding on necropsy of stranded cetaceans. To minimize masking by putrefaction gases, necropsy, and gas sampling must be performed as soon as possible. Before 24 h post mortem is recommended but preferably within 12 h post mortem. At necropsy, amount of bubbles (gas score) in decomposition code 2 in stranded cetaceans was found to be more important than merely presence vs. absence of bubbles from a pathological point of view. Deep divers presented higher abundance of gas bubbles, mainly composed of 70% nitrogen and 30% CO2, suggesting a higher predisposition of these species to suffer from decompression-related gas embolism. PMID:22675306

  6. Decompression vs. Decomposition: Distribution, Amount, and Gas Composition of Bubbles in Stranded Marine Mammals.

    PubMed

    de Quirós, Yara Bernaldo; González-Diaz, Oscar; Arbelo, Manuel; Sierra, Eva; Sacchini, Simona; Fernández, Antonio

    2012-01-01

    Gas embolic lesions linked to military sonar have been described in stranded cetaceans including beaked whales. These descriptions suggest that gas bubbles in marine mammal tissues may be more common than previously thought. In this study we have analyzed gas amount (by gas score) and gas composition within different decomposition codes using a standardized methodology. This broad study has allowed us to explore species-specific variability in bubble prevalence, amount, distribution, and composition, as well as masking of bubble content by putrefaction gases. Bubbles detected within the cardiovascular system and other tissues related to both pre- and port-mortem processes are a common finding on necropsy of stranded cetaceans. To minimize masking by putrefaction gases, necropsy, and gas sampling must be performed as soon as possible. Before 24 h post mortem is recommended but preferably within 12 h post mortem. At necropsy, amount of bubbles (gas score) in decomposition code 2 in stranded cetaceans was found to be more important than merely presence vs. absence of bubbles from a pathological point of view. Deep divers presented higher abundance of gas bubbles, mainly composed of 70% nitrogen and 30% CO(2), suggesting a higher predisposition of these species to suffer from decompression-related gas embolism.

  7. Field assessment of semi-aerobic condition and the methane correction factor for the semi-aerobic landfills provided by IPCC guidelines

    SciTech Connect

    Jeong, Sangjae; Nam, Anwoo; Yi, Seung-Muk; Kim, Jae Young

    2015-02-15

    Highlights: • CH{sub 4}/CO{sub 2} and CH{sub 4} + CO{sub 2}% are proposed as indices to evaluate semi-aerobic landfills. • A landfill which CH{sub 4}/CO{sub 2} > 1.0 is difficult to be categorized as semi-aerobic landfill. • Field conditions should be carefully investigated to determine landfill types. • The MCF default value for semi-aerobic landfills underestimates the methane emissions. - Abstract: According to IPCC guidelines, a semi-aerobic landfill site produces one-half of the amount of CH{sub 4} produced by an equally-sized anaerobic landfill site. Therefore categorizing the landfill type is important on greenhouse gas inventories. In order to assess semi-aerobic condition in the sites and the MCF value for semi-aerobic landfill, landfill gas has been measured from vent pipes in five semi-aerobically designed landfills in South Korea. All of the five sites satisfied requirements of semi-aerobic landfills in 2006 IPCC guidelines. However, the ends of leachate collection pipes which are main entrance of air in the semi-aerobic landfill were closed in all five sites. The CH{sub 4}/CO{sub 2} ratio in landfill gas, indicator of aerobic and anaerobic decomposition, ranged from 1.08 to 1.46 which is higher than the values (0.3–1.0) reported for semi-aerobic landfill sites and is rather close to those (1.0–2.0) for anaerobic landfill sites. The low CH{sub 4} + CO{sub 2}% in landfill gas implied air intrusion into the landfill. However, there was no evidence that air intrusion has caused by semi-aerobic design and operation. Therefore, the landfills investigated in this study are difficult to be classified as semi-aerobic landfills. Also MCF of 0.5 may significantly underestimate methane emissions compared to other researches. According to the carbon mass balance analyses, the higher MCF needs to be proposed for semi-aerobic landfills. Consequently, methane emission estimate should be based on field evaluation for the semi-aerobically designed landfills.

  8. Effect of gas composition and gas utilisation on the dynamic response of a proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Weydahl, Helge; Møller-Holst, Steffen; Børresen, Børre

    The transient response of a proton exchange membrane fuel cell (PEMFC) was measured for various cathode gas compositions and gas utilisations (fraction of supplied reactant gas which is consumed in the fuel cell reaction). For a PEMFC operated on pure hydrogen and oxygen, the cell voltage response to current steps was fast, with response times in the range 0.01-1 s, depending on the applied current. For a PEMFC supplied with air as cathode gas, an additional relaxation process related to oxygen transport caused a slower response (approximately 0.1-2 s depending on the applied current). Response curves up to approximately 0.01 s were apparently unaffected by gas composition and utilisation and were most likely dominated by capacitive discharge of the double layer and reaction with surplus oxygen residing in the cathode. The utilisation of hydrogen had only a minor effect on the response curves, while the utilisation of air severely influenced the PEMFC dynamics. Results suggested that air flow rates should be high to obtain rapid PEMFC response.

  9. Use of lightweight composites for GAS payload structures

    NASA Technical Reports Server (NTRS)

    Spencer, Mark B.

    1987-01-01

    A key element in the design of a small self-contained payload is the supporting structure. This structure must support the experiments and other components while using as little space and weight as possible. Hence, the structure material must have characteristics of being both strong and light. Aluminum was used for the structure on the first Purdue University payload, but consumed a relatively large percentage of the total payload weight. The current payload has a larger power supply requirement than did the previous payload. To allow additional weight for the batteries, a composite material has been chosen for the structure which has the required strength while being considerably lighter than aluminum. A radial fin design has been chosen for ease of composite material lay-up and its overall strength of design. A composite plate will connect the free ends of the fins and add strength and reduce vibration. The physical characteristics of the composite material and the method of open lay-up construction is described. Also discussed are the testing, modifications, and problems encountered during assembly of the experiments to the structure.

  10. Thermal treatment of soils contaminated with gas oil: influence of soil composition and treatment temperature.

    PubMed

    Piña, Juliana; Merino, Jerónimo; Errazu, Alberto F; Bucalá, Verónica

    2002-10-14

    Samples of two soils containing different organic matter contents, neat or contaminated with gas oil (diesel fuel oil) at 2.5 wt.% were heated from room temperature to different final temperatures (200-900 degrees C). The experiments, performed in an anaerobic media, simulate conditions pertinent to ex situ thermal desorptive and thermal destructive treatments. The products generated during the heating were collected and light gases were analyzed by gas chromatography. The results indicate that the chemical composition of the soil is a key factor since it strongly influences the quantity and composition of the off-gases. According to the liquid and light gas yields, the gas oil does not affect appreciably the generation of pyrolysis products of the own soil constituents and the gas oil does not suffer significant chemical transformations even at high operating temperatures (e.g. 900 degrees C). With surface areas of 16000 cm(2)/g (Soil A) and 85000 cm(2)/g (Soil B) based on the monolayer adsorbed model, 4 and 20%, respectively, of the original gas oil can be adsorbed. These values are in good agreement with experimental data. Even for high temperatures, the employed thermal treatment is capable to practically remove the gas oil from the soil bed without changing appreciably the original chemical composition of the contaminant.

  11. In situ measurement of gas composition changes in radio frequency plasmas using a quartz sensor

    SciTech Connect

    Suzuki, Atsushi; Nonaka, Hidehiko

    2009-09-15

    A simple method using a quartz sensor (Q-sensor) was developed to observe gas composition changes in radio frequency (rf) plasmas. The output depends on the gases' absolute pressure, molecular weight, and viscosity. The pressure-normalized quartz sensor output depends only on the molecular weight and viscosity of the gas. Consequently, gas composition changes can be detected in the plasmas if a sensor can be used in the plasmas. Influences imparted by the plasmas on the sensor, such as those by reactive particles (e.g., radicals and ions), excited species, electrons, temperature, and electric potentials during measurements were investigated to test the applicability of this quartz sensor measurement to plasma. The Q-sensor measurement results for rf plasmas with argon, hydrogen, and their mixtures are reproducible, demonstrating that the Q-sensor measurement is applicable for plasmas. In this work, pressure- and temperature-normalized Q-sensor output (NQO) were used to obtain the gas composition information of plasma. Temperature-normalization of the Q-sensor output enabled quartz sensor measurements near plasma electrodes, where the quartz sensor temperature increases. The changes in NQO agreed with results obtained by gas analysis using a quadrupole mass spectrometer. Results confirmed that the change in NQO is mainly attributable to changes in the densities and kinds of gas molecules in the plasma gas phase, not by other extrinsic influences of plasma. For argon, hydrogen, and argon-hydrogen plasmas, these changes correspond to reduction in nitrogen, production of carbon monoxide, and dissociation of hydrogen molecules, respectively. These changes in NQO qualitatively and somewhat quantitatively agreed with results obtained using gas analysis, indicting that the measurement has a potential application to obtain the gas composition in plasmas without disturbing industrial plasma processes.

  12. In situ measurement of gas composition changes in radio frequency plasmas using a quartz sensor.

    PubMed

    Suzuki, Atsushi; Nonaka, Hidehiko

    2009-09-01

    A simple method using a quartz sensor (Q-sensor) was developed to observe gas composition changes in radio frequency (rf) plasmas. The output depends on the gases' absolute pressure, molecular weight, and viscosity. The pressure-normalized quartz sensor output depends only on the molecular weight and viscosity of the gas. Consequently, gas composition changes can be detected in the plasmas if a sensor can be used in the plasmas. Influences imparted by the plasmas on the sensor, such as those by reactive particles (e.g., radicals and ions), excited species, electrons, temperature, and electric potentials during measurements were investigated to test the applicability of this quartz sensor measurement to plasma. The Q-sensor measurement results for rf plasmas with argon, hydrogen, and their mixtures are reproducible, demonstrating that the Q-sensor measurement is applicable for plasmas. In this work, pressure- and temperature-normalized Q-sensor output (NQO) were used to obtain the gas composition information of plasma. Temperature-normalization of the Q-sensor output enabled quartz sensor measurements near plasma electrodes, where the quartz sensor temperature increases. The changes in NQO agreed with results obtained by gas analysis using a quadrupole mass spectrometer. Results confirmed that the change in NQO is mainly attributable to changes in the densities and kinds of gas molecules in the plasma gas phase, not by other extrinsic influences of plasma. For argon, hydrogen, and argon-hydrogen plasmas, these changes correspond to reduction in nitrogen, production of carbon monoxide, and dissociation of hydrogen molecules, respectively. These changes in NQO qualitatively and somewhat quantitatively agreed with results obtained using gas analysis, indicting that the measurement has a potential application to obtain the gas composition in plasmas without disturbing industrial plasma processes.

  13. Perpetual landfilling through aeration of the waste mass; lessons from test cells in Georgia (USA).

    PubMed

    Read, A D; Hudgins, M; Phillips, P

    2001-01-01

    Municipal solid waste (MSW) landfills worldwide are experiencing the consequences of conventional landfilling techniques, whereby anaerobic conditions are created within the landfilled waste. Under anaerobic conditions within a landfill site slow stabilization of the waste mass occurs, producing methane, (an explosive 'green house' gas) and leachate (which can pollute groundwater) over long periods of time. As a potential solution, it was demonstrated that the aerobic degradation of MSW within a landfill can significantly increase the rate of waste decomposition and settlement, decrease the methane production and leachate leaving the system, and potentially increase the operational life of the site. Readily integrated into the existing landfill infrastructure, this approach can safely and cost-effectively convert a MSW landfill from anaerobic to aerobic degradation processes, thereby effectively composting much of the organic portions (one of the potentially polluting elements in a conventional landfill site) of the waste. This paper summarizes the successful results of two separate aerobic landfill projects located in Georgia (USA) and discusses the potential economic and environmental impacts to worldwide solid waste management practices.

  14. The best MSW treatment option by considering greenhouse gas emissions reduction: a case study in Georgia.

    PubMed

    Tayyeba, Omid; Olsson, Monika; Brandt, Nils

    2011-08-01

    The grave concern over climate change and new economic incentives such as the clean development mechanism (CDM) have given more weight to the potential of projects for reducing greenhouse gas (GHG) emissions. In the Adjara solid waste management project, even though the need for reductions in GHG emissions is acknowledged, it is not one of the key factors for selecting the most appropriate treatment method. This study addresses the benefit of various solid waste treatment methods that could be used in the Adjara project in terms of reducing GHG emissions. Seven different options for solid waste treatment are examined: open dumping as the baseline case, four options for landfill technology (no provision of landfill gas capture, landfill gas capture with open flare system, with enclosed flare system and with electricity generation), composting and anaerobic digestion with electricity production. CDM methodologies were used to quantify the amount of reductions for the scenarios. The study concludes sanitary landfill with capture and burning of landfill gas by an enclosed flare system could satisfy the requirements, including GHG reduction potential. The findings were tested for uncertainty and sensitivity by varying the data on composition and amount of waste and were found to be robust.

  15. Real-time Multi-GAS sensing of volcanic gas composition: experiences from the permanent Etna and Stromboli networks

    NASA Astrophysics Data System (ADS)

    Liuzzo, M.; Aiuppa, A.; Giudice, G.; Gurrieri, S.

    2009-04-01

    Measuring the composition of volcanic gases released from active volcanoes brings profound insights into our understanding of volcanic processes and, when combined with other methods, contributes to volcano monitoring. Volcanic gases can now be measured with a large variety of highly sophisticated techniques, but high-resolution routine measurements are possible with only a few of them (e.g., FTIR), and typically for only a few compounds. The Multi-GAS (Multi-component Gas Analyser System) technique has recently been demonstrated as a powerful method for the real-time high-resolution measurement of volcanic gas plumes, as has been used for discrete measurement surveys at several volcanoes including, among others, Etna, Stromboli and Vulcano in Italy, Villarica in Chile, Masaya in Nicaragua, Yasur and Ambrym in Vanuatu Republic, Miyakejima and Asama in Japan, and Soufriere Hill volcano on Montserrat. More recently, permanent Multi-GAS devices have been installed for the first on an active volcano at Etna (in 2004) and Stromboli (in 2006), allowing for the acquisition of unprecedented accurate time-series of volcanic gas compositions (for the three major components CO2-SO2-H2O) at both volcanoes. Here, we review the results of such permanent MultiGAS networks, and we demonstrate their implications for the comprehension of volcanic degassing processes. We also show that cycles of increase of Multi-GAS-sensed CO2/SO2 ratios preceded the most recent eruptive episodes on Etna in 2006-2008 and Stromboli in 2007, providing us with valuable precursor information on magma ascent within the shallow plumbing systems of these very active volcanoes, and thus deeply contributing to volcano hazard mitigation.

  16. Warming effects on greenhouse gas fluxes in peatlands are modulated by vegetation composition.

    PubMed

    Ward, Susan E; Ostle, Nicholas J; Oakley, Simon; Quirk, Helen; Henrys, Peter A; Bardgett, Richard D

    2013-10-01

    Understanding the effects of warming on greenhouse gas feedbacks to climate change represents a major global challenge. Most research has focused on direct effects of warming, without considering how concurrent changes in plant communities may alter such effects. Here, we combined vegetation manipulations with warming to investigate their interactive effects on greenhouse gas emissions from peatland. We found that although warming consistently increased respiration, the effect on net ecosystem CO2 exchange depended on vegetation composition. The greatest increase in CO2 sink strength after warming was when shrubs were present, and the greatest decrease when graminoids were present. CH4 was more strongly controlled by vegetation composition than by warming, with largest emissions from graminoid communities. Our results show that plant community composition is a significant modulator of greenhouse gas emissions and their response to warming, and suggest that vegetation change could alter peatland carbon sink strength under future climate change.

  17. Gas-phase detonation propagation in mixture composition gradients.

    PubMed

    Kessler, D A; Gamezo, V N; Oran, E S

    2012-02-13

    The propagation of detonations through several fuel-air mixtures with spatially varying fuel concentrations is examined numerically. The detonations propagate through two-dimensional channels, inside of which the gradient of mixture composition is oriented normal to the direction of propagation. The simulations are performed using a two-component, single-step reaction model calibrated so that one-dimensional detonation properties of model low- and high-activation-energy mixtures are similar to those observed in a typical hydrocarbon-air mixture. In the low-activation-energy mixture, the reaction zone structure is complex, consisting of curved fuel-lean and fuel-rich detonations near the line of stoichiometry that transition to decoupled shocks and turbulent deflagrations near the channel walls where the mixture is extremely fuel-lean or fuel-rich. Reactants that are not consumed by the leading detonation combine downstream and burn in a diffusion flame. Detonation cells produced by the unstable reaction front vary in size across the channel, growing larger away from the line of stoichiometry. As the size of the channel decreases relative to the size of a detonation cell, the effect of the mixture composition gradient is lessened and cells of similar sizes form. In the high-activation-energy mixture, detonations propagate more slowly as the magnitude of the mixture composition gradient is increased and can be quenched in a large enough gradient. PMID:22213660

  18. Livingston Parish Landfill Methane Recovery Project (Feasibility Study)

    SciTech Connect

    White, Steven

    2012-11-15

    The Woodside Landfill is owned by Livingston Parish, Louisiana and is operated under contract by Waste Management of Louisiana LLC. This public owner/private operator partnership is commonplace in the solid waste industry today. The landfill has been in operation since approximately 1988 and has a permitted capacity of approximately 41 million cubic yards. Based on an assumed in-place waste density of 0.94 ton per cubic yard, the landfill could have an expected design capacity of 39.3 million tons. The landfill does have an active landfill gas collection and control system (LFGCCS) in place because it meets the minimum thresholds for the New Source Performance Standards (NSPS). The initial LFGCS was installed prior to 2006 and subsequent phases were installed in 2007 and 2010. The Parish received a grant from the United States Department of Energy in 2009 to evaluate the potential for landfill gas recovery and utilization at the Woodside Landfill. This includes a technical and economic feasibility study of a project to install a landfill gas to energy (LFGTE) plant and to compare alternative technologies. The LFGTE plant can take the form of on-site electrical generation, a direct use/medium Btu option, or a high-Btu upgrade technology. The technical evaluation in Section 2 of this report concludes that landfill gas from the Woodside landfill is suitable for recovery and utilization. The financial evaluations in sections 3, 4, and 5 of this report provide financial estimates of the returns for various utilization technologies. The report concludes that the most economically viable project is the Electricity Generation option, subject to the Parish’s ability and willingness to allocate adequate cash for initial capital and/or to obtain debt financing. However, even this option does not present a solid return: by our estimates, there is a 19 year simple payback on the electricity generation option. All of the energy recovery options discussed in this report

  19. Variation of Volcanic Gas Composition at a Persistently Degassing Asama Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Shinohara, H.; Ohminato, T.; Takeo, M.

    2013-12-01

    Asama volcano at central Japan is a persistently degassing andesitic volcano and repeated eruptions every several years. The recent eruptions occurred in September 2004, August 2008 and February 2009 and are followed by increase of the volcanic gas emission during several months. The SO2 flux is typically 1,000-4,000 t/d during the high flux period after the eruption, whereas the flux is around 100 t/d during the low gas flux periods (JMA, 2013; Ohwada et al., in review). This study aims to understand the controlling process of volcano degassing based on the volcanic gas composition data. In particular, we focus to evaluate the gas composition contrast between the high and low gas flux periods. As the fumaroles and degassing vent locate in the summit crater of 500-m-diamter and are inaccessible, we estimated the gas composition by plume measurements with the Multi-GAS at the crater rim. The HCl/SO2 ratios are obtained by the alkali-filter trap. We started the repeat Multi-GAS measurements in 2004 and installed an automatic Multi-GAS monitoring station for a daily measurement at the western rim of the summit crater in 2010. The gas compositions obtained by the Multi-GAS measurements are often scattered even during the day of measurements, in particular during the low flux period and the scatter is likely due to variable contamination of gases from low-temperature fumaroles locating along the crater rim because the low-temperature fumaroles locate closer to the measurement site that the major degassing vent at the bottom of the crater. If we plot the gas concentration ratio, such as CO2/SO2 against SO2 concentration, the ratio commonly converges to a certain value at high SO2 concentration and this ratio is considered as representative of the major gas emission. The estimated molar ratios are CO2/SO2=1×0.5, HCl/SO2=0.2×0.1 and H2O/SO2=60×30 without clear contrast during the high and low flux periods. The CO2/SO2 ratios obtained based on a single day data tend to

  20. Variations in dissolved gas compositions of reservoir fluids from the Coso geothermal field

    SciTech Connect

    Williams, Alan E.; Copp, John F.

    1991-01-01

    Gas concentrations and ratios in 110 analyses of geothermal fluids from 47 wells in the Coso geothermal system illustrate the complexity of this two-phase reservoir in its natural state. Two geographically distinct regions of single-phase (liquid) reservoir are present and possess distinctive gas and liquid compositions. Relationships in soluble and insoluble gases preclude derivation of these waters from a common parent by boiling or condensation alone. These two regions may represent two limbs of fluid migration away from an area of two-phase upwelling. During migration, the upwelling fluids mix with chemically evolved waters of moderately dissimilar composition. CO{sub 2} rich fluids found in the limb in the southeastern portion of the Coso field are chemically distinct from liquids in the northern limb of the field. Steam-rich portions of the reservoir also indicate distinctive gas compositions. Steam sampled from wells in the central and southwestern Coso reservoir is unusually enriched in both H{sub 2}S and H{sub 2}. Such a large enrichment in both a soluble and insoluble gas cannot be produced by boiling of any liquid yet observed in single-phase portions of the field. In accord with an upflow-lateral mixing model for the Coso field, at least three end-member thermal fluids having distinct gas and liquid compositions appear to have interacted (through mixing, boiling and steam migration) to produce the observed natural state of the reservoir.

  1. Autoresonant-spectrometric determination of the residual gas composition in the ALPHA experiment apparatus

    SciTech Connect

    Amole, C.; Capra, A.; Menary, S.; Ashkezari, M. D.; Hayden, M. E.; Baquero-Ruiz, M.; Chapman, S.; Little, A.; Povilus, A.; So, C.; Turner, M.; Bertsche, W.; Butler, E.; Cesar, C. L.; Silveira, D. M.; Charlton, M.; Eriksson, S.; Isaac, C. A.; Madsen, N.; Napoli, S. C.; Collaboration: ALPHA Collaboration; and others

    2013-06-15

    Knowledge of the residual gas composition in the ALPHA experiment apparatus is important in our studies of antihydrogen and nonneutral plasmas. A technique based on autoresonant ion extraction from an electrostatic potential well has been developed that enables the study of the vacuum in our trap. Computer simulations allow an interpretation of our measurements and provide the residual gas composition under operating conditions typical of those used in experiments to produce, trap, and study antihydrogen. The methods developed may also be applicable in a range of atomic and molecular trap experiments where Penning-Malmberg traps are used and where access is limited.

  2. Autoresonant-spectrometric determination of the residual gas composition in the ALPHA experiment apparatus.

    PubMed

    Amole, C; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Butler, E; Capra, A; Cesar, C L; Chapman, S; Charlton, M; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Isaac, C A; Jonsell, S; Kurchaninov, L; Little, A; Madsen, N; McKenna, J T K; Menary, S; Napoli, S C; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Rasmussen, C Ø; Robicheaux, F; Sarid, E; Silveira, D M; Stracka, S; So, C; Thompson, R I; Turner, M; van der Werf, D P; Wurtele, J S; Zhmoginov, A

    2013-06-01

    Knowledge of the residual gas composition in the ALPHA experiment apparatus is important in our studies of antihydrogen and nonneutral plasmas. A technique based on autoresonant ion extraction from an electrostatic potential well has been developed that enables the study of the vacuum in our trap. Computer simulations allow an interpretation of our measurements and provide the residual gas composition under operating conditions typical of those used in experiments to produce, trap, and study antihydrogen. The methods developed may also be applicable in a range of atomic and molecular trap experiments where Penning-Malmberg traps are used and where access is limited.

  3. Preparation and characterization of composite membrane for high temperature gas separation

    SciTech Connect

    Ilias, S.; King, F.G.; Su, N.

    1994-10-01

    The objective of this project is to develop thin film palladium membranes for separation of hydrogen in high temperature applications. The authors plan to use electroless plating to deposit thin palladium films on microporous ceramic and silver substrates and then characterize the membrane in terms of permeability and selectivity for gas separation. To accomplish the research objective, the project requires three tasks: Development of a process for composite membrane fabrication; Characterization of composite membrane; and Development of theoretical model for hydrogen gas separation. The experimental procedures are described.

  4. Natural gas constituent and carbon isotopic composition in petroliferous basins, China

    NASA Astrophysics Data System (ADS)

    Zhu, Guangyou; Wang, Zhengjun; Dai, Jinxing; Su, Jing

    2014-02-01

    There are abundant gas resources in petroliferous basins of China. Large to midsize gas fields are found in Eastern, central and Western of China. However, origin, constituents and isotopic composition of natural gas in different gas fields are varied distinctly, and some present strong chemical secondary alteration and show variation both in age and space. Based on the systematic analysis of constituents and carbon isotope of a large number of gas samples, combined with the geological characteristics, this paper classifies the origins of the gases, explores the gas isotope characteristics and evolutionary regulation with the variation time and space, and further discusses the distinctive geochemistry of the gases in China. These gases are dominated by dry gas, its methane carbon isotope values range from -10‰ to -70‰, ethane from -16‰ to -52‰, propane from -13‰ to -43‰, and butane from -18‰ to -34‰. The carbon isotopes of most gases show the characteristics of humic-derived gas and crude oil cracked gas. In addition, large primary biogenic gas fields have been discovered in the Qaidam basin; inorganic-derived alkane gases have been discovered in deep of the Songliao Basin. Half of these gas fields are characterized by the alkane carbon isotope reversal in different degrees. Research indicates there are several reasons can result in carbon isotope reversal. Firstly, gas charge of different genetic types or different source in one gas reservoir may cause carbon isotope reversal. Besides, high-over mature evolution of gas can also lead to the carbon isotopic reversal of alkanes. Thirdly, secondary alteration of hydrocarbons may also result in abnormal distribution of carbon isotope, isotope transforms to unusual light and heavy.

  5. Noble gas isotopic composition as a key reference parameter in a planetary atmospheric evolution model

    NASA Astrophysics Data System (ADS)

    Ozima, M.

    2010-12-01

    The isotopic composition of noble gases is a key reference parameter in discussing the evolution of planetary atmospheres. Currently, two widely occurring noble gas components are identified in the early solar system, one is the Solar Wind noble gas (SW-noble gas, hereafter) and another is the Q-noble gas in unaltered meteorites: both noble gases are characterized by their ubiquitous occurrence and high isotopic homogeneity. Since the SW-noble gas is directly ejected from the Sun, it has been assumed to be a good proxy of the average noble gas isotopic composition in the Sun, namely the solar noble gas. The systematic enrichment of the heavier isotopes in the Q-noble gas relative to the SW-noble gas is then commonly attributed to its isotopic fractionation from the SW-noble gas. However, the isotopic compositions of the SW-noble gas either implanted on lunar soils or trapped by artificial targets show considerable isotopic variation depending on the velocity of the Solar Wind. Therefore, it is important to examine how closely the SW-noble gas represents the indigenous solar noble gas component or the mean isotopic composition of noble gases of the Sun. Here we show that the isotopic composition of the SW-noble gas is substantially fractionated relative to the solar value, and therefore should not be used as a reference parameter. We further suggest that the post D-burning Q-noble gas (see below) is the better proxy of the solar noble gas, and this should be used as a reference of the Solar noble gas isotopic composition in discussing the planetary atmospheric evolution. The most distinct difference between the Q- and the SW-noble gas is apparent in a 3He/4He isotopic ratio: 4.64e-4 in Q-He [1], but 1.23e-4 in SW-He[2]. The difference is attributed to the conversion of deuteron (D) to 3He in the Sun, namely the D-burning [3], due to high temperature during the pre-main sequence stage of the Sun. With the use of recent data on D/H ratios from helio-seismology [4] and

  6. Evaluation of methane emissions from Palermo municipal landfill: Comparison between field measurements and models

    SciTech Connect

    Di Bella, Gaetano; Di Trapani, Daniele; Viviani, Gaspare

    2011-08-15

    Methane (CH{sub 4}) diffuse emissions from Municipal Solid Waste (MSW) landfills represent one of the most important anthropogenic sources of greenhouse gas. CH{sub 4} is produced by anaerobic biodegradation of organic matter in landfilled MSW and constitutes a major component of landfill gas (LFG). Gas recovery is a suitable method to effectively control CH{sub 4} emissions from landfill sites and the quantification of CH{sub 4} emissions represents a good tool to evaluate the effectiveness of a gas recovery system in reducing LFG emissions. In particular, LFG emissions can indirectly be evaluated from mass balance equations between LFG production, recovery and oxidation in the landfill, as well as by a direct approach based on LFG emission measurements from the landfill surface. However, up to now few direct measurements of landfill CH{sub 4} diffuse emissions have been reported in the technical literature. In the present study, both modeling and direct emission measuring methodologies have been applied to the case study of Bellolampo landfill located in Palermo, Italy. The main aim of the present study was to evaluate CH{sub 4} diffuse emissions, based on direct measurements carried out with the flux accumulation chamber (static, non-stationary) method, as well as to obtain the CH{sub 4} contoured flux map of the landfill. Such emissions were compared with the estimate achieved by means of CH{sub 4} mass balance equations. The results showed that the emissions obtained by applying the flux chamber method are in good agreement with the ones derived by the application of the mass balance equation, and that the evaluated contoured flux maps represent a reliable tool to locate areas with abnormal emissions in order to optimize the gas recovery system efficiency.

  7. An experimental setup with ultrasonic gas analyzers and real time analysis of the composition of a binary gas mixture

    NASA Astrophysics Data System (ADS)

    Vacek, V.; Vítek, M.; Doubek, M.

    2013-04-01

    This paper describes an automated measuring apparatus with an ultrasonic gas analyzer and realtime analysis of the composition of the gas. The apparatus is designed for preparing binary gas mixtures and making measurements in a wide range of pressures (from 0.8 bara to 15 bara) and temperatures (between -15°C and 80°C). The apparatus was developed to determine the thermophysical properties of fluorocarbon mixtures for potential use in the cooling circuits of several Large Hadron Collider projects at CERN. The design of its control system took into account the safety and reliability o the gas analyzer, and the need to limit the presence of laboratory personnel. The control system was implemented in PVSS-II, the Supervisory, Control and Data Acquisition standard chosen for LHC and its experiments at CERN. The second part of the paper describes the implementation and verification of the algorithm for continuous real-time determination of the composition of the refrigerant mixture. The algorithm is based on minimizing the quadratic norm fromthe measured data and from the pre-generated look-up tables acquired from the NIST REFPROP software package.

  8. Central Appalachian basin natural gas database: distribution, composition, and origin of natural gases

    USGS Publications Warehouse

    Román Colón, Yomayra A.; Ruppert, Leslie F.

    2015-01-01

    The U.S. Geological Survey (USGS) has compiled a database consisting of three worksheets of central Appalachian basin natural gas analyses and isotopic compositions from published and unpublished sources of 1,282 gas samples from Kentucky, Maryland, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. The database includes field and reservoir names, well and State identification number, selected geologic reservoir properties, and the composition of natural gases (methane; ethane; propane; butane, iso-butane [i-butane]; normal butane [n-butane]; iso-pentane [i-pentane]; normal pentane [n-pentane]; cyclohexane, and hexanes). In the first worksheet, location and American Petroleum Institute (API) numbers from public or published sources are provided for 1,231 of the 1,282 gas samples. A second worksheet of 186 gas samples was compiled from published sources and augmented with public location information and contains carbon, hydrogen, and nitrogen isotopic measurements of natural gas. The third worksheet is a key for all abbreviations in the database. The database can be used to better constrain the stratigraphic distribution, composition, and origin of natural gas in the central Appalachian basin.

  9. Landfilling ash/sludge mixtures

    SciTech Connect

    Benoit, J.; Eighmy, T.T.; Crannell, B.S.

    1999-10-01

    The geotechnical properties of a mixture of municipal solid waste incinerator bottom ash and municipal wastewater treatment plant sludge was investigated for a proposed ash/sludge secure landfill. The components as well as mixtures ranging from 10:1 to 5:1 (ash:sludge, by volume) were evaluated, where appropriate, for a number of geotechnical index and mechanical properties including particle size, water content, specific gravity, density-moisture relationships, shear strength, and compressibility. The results from a compactibility study and stability analysis of the proposed landfill were used to help approve a landfill codisposal concept; a full-scale facility was constructed and is currently operating successfully.

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

    NASA Astrophysics Data System (ADS)

    Mwiganga, M.; Kansiime, F.

    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 (<200 m) and cattle farms. It is also located upstream of a wetland. The landfill generates nuisances like bad odour; there is scattering of waste by scavenger birds, flies and vermin. Industrial and hospital wastes are disposed of at the landfill without pre-treatment. The concentration of variables (nutrients, bacteriological indicators, BOD and heavy metals) in the leachate were higher than those recommended in the National Environment Standards for Discharge of Effluent into Water and on Land. A composite sample that was taken 1500 m down stream indicated that the wetland considerably reduced the concentration of the parameters that were measured except for sulfides. Despite the fact that there was accumulation of metals in the sediments, the concentration has not reached toxic levels to humans. Soil and plant analyses indicated deficiencies of zinc and copper. The concentration of these elements was lowest in the leachate canal.

  11. Ceramic composite liner material for gas turbine combustors

    NASA Technical Reports Server (NTRS)

    Ercegovic, D. B.; Walker, C. L.; Norgren, C. T.

    1984-01-01

    Advanced commercial and military gas turbine engines may operate at combustor outlet temperatures in excess of 1920 K (3000 F). At these temperatures combustors liners experience extreme convective and radiative heat fluxes. The ability of a plasma sprayed ceramic coating to reduce liner metal temperature has been recognized. However, the brittleness of the ceramic layer and the difference in thermal expansion with the metal substrate has caused cracking, spalling and some separation of the ceramic coating. Research directed at turbine tip seals (or shrouds) has shown the advantage of applying the ceramic to a compliant metal pad. This paper discusses recent studies of applying ceramics to combustor liners in which yttria stabilized zirconia plasma sprayed on compliant metal substrates which were exposed to near stoichiometric combustion, presents performance and durability results, and describes a conceptual design for an advanced, small gas turbine combustor. Test specimens were convectively cooled or convective-transpiration cooled and were evaluated in a 10 cm square flame tube combustor at inlet air temperatures of 533 K (500 F) and at a pressure of 0.5 MPa (75 psia). The ceramics were exposed to flame temperatures in excess of 2000 K (3320 F). Results appear very promising with all 30 specimens surviving a screening test and one of two specimens surviving a cyclic durability test.

  12. Separation of gases through gas enrichment membrane composites

    DOEpatents

    Swedo, R.J.; Kurek, P.R.

    1988-07-19

    Thin film composite membranes having as a permselective layer a film of a homopolymer of certain vinyl alkyl ethers are useful in the separation of various gases. Such homopolymers have a molecular weight of greater than 30,000 and the alkyl group of the vinyl alkyl monomer has from 4 to 20 carbon atoms with branching within the alkyl moiety at least at the carbon atom bonded to the ether oxygen or at the next adjacent carbon atom. These membranes show excellent hydrolytic stability, especially in the presence of acidic or basic gaseous components.

  13. Separation of gases through gas enrichment membrane composites

    DOEpatents

    Swedo, Raymond J.; Kurek, Paul R.

    1988-01-01

    Thin film composite membranes having as a permselective layer a film of a homopolymer of certain vinyl alkyl ethers are useful in the separation of various gases. Such homopolymers have a molecular weight of greater than 30,000 and the alkyl group of the vinyl alkyl monomer has from 4 to 20 carbon atoms with branching within the alkyl moiety at least at the carbon atom bonded to the ether oxygen or at the next adjacent carbon atom. These membranes show excellent hydrolytic stability, especially in the presence of acidic or basic gaseous components.