Science.gov

Sample records for landfill gas composition

  1. Characterization of landfill gas composition at the Fresh Kills municipal solid-waste landfill

    SciTech Connect

    Eklund, B.; Anderson, E.P.; Walker, B.L.; Burrows, D.B.

    1998-08-01

    The most common disposal method in the US for municipal solid waste (MSW) is burial in landfills. Until recently, air emissions from these landfills were not regulated. Under the New Source Performance Standards and Emission Guidelines for MSW landfills, MSW operators are required to determine the nonmethane organic gas generation rate of their landfill through modeling and/or measurements. This paper summarizes speciated nonmethane organic compound (NMOC) measurement data collected during an intensive, short-term field program. Over 250 separate landfill gas samples were collected from emission sources at the Fresh Kills landfill in New York City and analyzed for approximately 150 different analytes. The average total NMOC value for the landfill was 438 ppmv (as hexane) versus the regulatory default value of 4,000 ppmv (as hexane). Over 70 individual volatile organic compounds (VOCs) were detected and quantified in the landfill gas samples. The typical gas composition for this landfill was determined as well as estimates of the spatial, temporal, and measurement variability in the gas composition. The data for NMOC show that the gas composition within the landfill is equivalent to the composition of the gas exiting the landfill through passive vents and through the soil cover.

  2. 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. PMID:21074982

  3. Determination of landfill gas composition and pollutant emission rates at fresh kills landfill. Volume 1. Project report. Final report

    SciTech Connect

    1995-12-07

    Air emissions of landfill gas pollutants at Fresh Kills Landfill, located in Staten Island, NY, were estimated based on three weeks of sampling of flow, concentration, and flux at passive vents, gas extraction wells, gas collection plant headers, and the landfill surface conducted by Radian Corporation in 1995. Emission rates were estimated for 202 pollutants, including hydrogen sulfide, mercury vapor, speciated volatile organic compounds, methane, and carbon dioxide. Results indicate that large amounts of mercury enter the methane, and carbon dioxide. Results indicate that large amounts of mercury enter the methane recovery plant. Emission factors based on the results are presented.

  4. Determination of landfill gas composition and pollutant emission rates at fresh kills landfill - project data (for microcomputers). Data file

    SciTech Connect

    1995-12-31

    Air emissions of landfill gas pollutants at Fresh Kills Landfill, located in Staten Island, NY, were estimated based on three weeks of sampling of flow, concentration, and flux at passive vents, gas extraction wells, gas collection plant headers, and the landfill surface conducted by Radian Corporation in 1995. Emission rates were estimated for 202 pollutants, including hydrogen sulfide, mercury vapor, speciated volatile organic compounds, methane, and carbon dioxide. Results indicate that large amounts of mercury enter the methane recovery plant. Emission factors based on the results are presented.

  5. 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...

  6. Determination of landfill gas composition and pollutant emission rates at fresh kills landfill. Volume 2. Appendices to project report. Final report

    SciTech Connect

    1995-12-07

    Air emissions of landfill gas pollutants at Fresh Kills Landfill, located in Staten Island, NY, were estimated based on three weeks of sampling of flow, concentration, and flux at passive vents, gas extraction wells, gas collection plant headers, and the landfill surface conducted by Radian Corporation in 1995. Emission rates were estimated for 202 pollutants, including hydrogen sulfide, mercury vapor, speciated volatile organic compounds, methane, and carbon dioxide. Results indicate that large amounts of mercury enter the methane, and carbon dioxide. Results indicate that large amounts of mercury enter the methane recovery plant. Emission factors based on the results are presented.

  7. 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)

  8. Beneficial use of landfill gas at the Burnsville sanitary landfill

    SciTech Connect

    Michels, M.; Morely, J.; Kitts, S.

    1995-08-01

    A beneficial use study was conducted to determine the most economical method of converting landfill gas to energy at the Burnsville Sanitary Landfill. The existing 98.5-acre landfill is permitted for nine million cubic yards of municipal solid waste and estimated to generate significant quantities of landfill gas. The beneficial use study reviewed four options to utilize the landfill gas, as follows; generate electric power and utilize on site; generate electric power and sell to local utility; clean up the landfill gas and sell to natural gas company; and sell landfill gas to nearby asphalt and concrete plants in the summer months, then to 15 commercial businesses for heat in the winter months. The study concluded that it is most economical to generate electricity and sell power to the local utility. Since May 1994, 3.2 megawatts of power have been generated. Upon site closure, the potential for 4.8 megawatts of power generation may exist.

  9. 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.

  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. Landfill gas to electricity demonstration project

    NASA Astrophysics Data System (ADS)

    Giuliani, A. J.; Cagliostro, L. A.

    1982-03-01

    Medium Btu methane gas is a naturally occurring by product of anaerobic digestion of landfilled municipal solid waste. The energy potential of landfill gas in New York State is estimated to be 61 trillion Btu's per year or the equivalent of 10 percent of the natural gas used annually in the State. The 18-month Landfill Gas to Electricity Demonstration Project conducted at the Fresh Kills Landfill in Staten Island, New York conclusively demonstrated that landfill gas is an acceptable fuel for producing electricity using an internal combustion engine/generator set. Landfill gas proved to be a reliable and consistent fuel source during a six-month field test program. Engine exhaust emissions were determined to be comparable to that of natural gas and no unusually high corrosion rates on standard pipeline material were found.

  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 ENERGY UTILIZATION: TECHNOLOGY OPTIONS AND CASE STUDIES

    EPA Science Inventory

    The report discusses technical, environmental, and other issues associated with using landfill gas as fuel, and presents case studies of projects in the U.S. illustrating some common energy uses. he full report begins by covering basic issues such as gas origin, composition, and ...

  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. 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.

  17. 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.

  18. Surface emission of landfill gas from solid waste landfill

    NASA Astrophysics Data System (ADS)

    Park, Jin-Won; Shin, Ho-Chul

    The surface emission of landfill gas (LFG) was studied to estimate the amount of LFG efflux from solid waste landfills using an air flux chamber. LFG efflux increased as atmospheric temperature increased during the day, and the same pattern for the surface emission was observed for the change of seasons. LFG efflux rate decreased from summer through winter. The average LFG efflux rates of winter, spring and summer were 0.1584, 0.3013 and 0.8597 m 3 m -2 h -1 respectively. The total amount of surface emission was calculated based on the seasonal LFG efflux rate and the landfill surface area. From the estimates of LFG generation, it is expected that about 30% of the generated LFG may be released through the surface without extraction process. As forced extraction with a blower proceeded, the extraction well pressure decreased from 1100 to -100 mm H 2O, and the LFG surface efflux decreased markedly above 80%. Thus, the utilization of LFG by forced extraction would be the good solution for global warming and air pollution by LFG.

  19. 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.

  20. 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.

  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. 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...

  3. 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...

  4. 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 ...

  5. 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.

  6. 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.

  7. Evaluation of landfill gas as an energy source

    NASA Astrophysics Data System (ADS)

    1980-12-01

    The benefits and problems associated with landfill gas recovery were considered by the City of Baltimore, resulting in the structuring and testing of a realistic gas recovery evaluation procedure for use by local governments. The Baltimore methodology is summarized and results of its application to a large landfill in the Baltimore area are presented. The landfill gas generation process potential uses for the recovered gas, and treatment requirements are covered.

  8. Landfill gas pretreatment for fuel cell applications

    NASA Astrophysics Data System (ADS)

    Sandelli, G. J.; Trocciola, J. C.; Spiegel, R. J.

    1994-04-01

    The US Environmental Protection Agency (EPA) has proposed regulations (1) to control air emissions from municipal solid waste landfills. If these regulations are adopted, they would require waste methane mitigation in order to prevent emission into the atmosphere and reduce the effect on global warming. One potential use of the waste methane is in a device which produces energy, the fuel cell. This device would reduce air emissions affecting global warming, acid rain, and other health and environmental issues. By producing useable energy, it would also reduce our dependency on foreign oil. This paper discusses the US EPA 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 needed to be addressed: (1) a landfill gas cleanup method that would remove contaminants from the gas sufficient for fuel cell operation; and (2) successful operation of a commercial fuel cell power plant on that lower-heating value waste methane gas.

  9. Case study: City of Industry landfill gas recovery operation

    SciTech Connect

    1981-11-01

    Development of civic, recreation, and conservation facilities throughout a 150-acre site which had been used for waste disposal from 1951 to 1970 is described. The history of the landfill site, the geology of the site, and a test well program to assess the feasibility of recoverying landfill gas economically from the site are discussed. Based on results of the test well program, the City of Industry authorized the design and installation of a full-scale landfill gas recovery system. Design, construction, and operation of the system are described. The landfill gas system provides fuel for use in boilers to meet space heating and hot water demands for site development (MCW)

  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. 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.

  13. 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

  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. 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...

  17. 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.

  18. Gas production by accelerated in situ bioleaching of landfills

    SciTech Connect

    Ghosh, S.

    1982-04-06

    A process for improved gas production and accelerated stabilization of landfills by accelerated in situ bioleaching of organic wastes by acid forming bacteria in substantially sealed landfills, passing the leachate of hydrolysis and liquefaction products of microbial action of the microorganisms with the organic material to an acid phase digester to regenerate the activated culture of acid forming microorganisms for recirculation to the landfill, passing the supernatant from the acid phase digester to a methane phase digester operated under conditions to produce methane rich gas. The supernatant from the methane phase digester containing nutrients for the acid forming microorganisms and added sewage sludge or other desired nutrient materials are circulated through the landfill. Low Btu gas is withdrawn from the acid phase digester while high Btu gas is withdrawn from the methane phase digester and may be upgraded for use as SNG. The process of this invention is applicable to small as well as large organic waste landfills, provides simultaneous disposal of municipal solid waste and sewage sludge or other aqueous organic waste in a landfill which may be stabilized much more quickly than an uncontrolled landfill as presently utilized.

  19. LANDFILL GAS AND THE GREENHOUSE EFFECT

    EPA Science Inventory

    The paper is an overview of the current understanding of methane emissions from landfills that contribute to global climate change. The factors affecting landfill emissions are described and the uncertainties are identified. There appears to be a consensus in the international co...

  20. 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)

  1. Diversity and activity of methanotrophs in landfill cover soils with and without landfill gas recovery systems.

    PubMed

    Su, Yao; Zhang, Xuan; Xia, Fang-Fang; Zhang, Qi-Qi; Kong, Jiao-Yan; Wang, Jing; He, Ruo

    2014-05-01

    Aerobic CH4 oxidation plays an important role in mitigating CH4 release from landfills to the atmosphere. Therefore, in this study, oxidation activity and community of methanotrophs were investigated in a subtropical landfill. Among the three sites investigated, the highest CH4 concentration was detected in the landfill cover soil of the site (A) without a landfill gas (LFG) recovery system, although the refuse in the site had been deposited for a longer time (∼14-15 years) compared to the other two sites (∼6-11 years) where a LFG recovery system was applied. In April and September, the higher CH4 flux was detected in site A with 72.4 and 51.7gm(-2)d(-1), respectively, compared to the other sites. The abundance of methanotrophs assessed by quantification of pmoA varied with location and season. A linear relationship was observed between the abundance of methanotrophs and CH4 concentrations in the landfill cover soils (R=0.827, P<0.001). The key factors influencing the methanotrophic diversity in the landfill cover soils were pH, the water content and the CH4 concentration in the soil, of which pH was the most important factor. Type I methanotrophs, including Methylococcus, Methylosarcina, Methylomicrobium and Methylobacter, and type II methanotrophs (Methylocystis) were all detected in the landfill cover soils, with Methylocystis and Methylosarcina being the dominant genera. Methylocystis was abundant in the slightly acidic landfill cover soil, especially in September, and represented more than 89% of the total terminal-restriction fragment abundance. These findings indicated that the LFG recovery system, as well as physical and chemical parameters, affected the diversity and activity of methanotrophs in landfill cover soils. PMID:24332193

  2. LANDFILL GAS ENERGY UTILIZATION: TECHNICAL AND NON-TECHNICAL CONSIDERATIONS

    EPA Science Inventory

    The paper discusses technical issues associated with the use of landfill gas (LFG) compared with natural gas--which is the primary fuel used for energy conversion equipment such as internal combustion engines, gas turbines, and fuel cells. FG is a medium-heating-value fuel contai...

  3. Landfill gas recovery system and method with pressure symmetry

    SciTech Connect

    Zison, S.W.; Roqueta, A.

    1984-09-04

    In a landfill gas recovery system, the breakthrough danger is minimized, and the system efficiency is improved, by providing pressure-equalizing low-impedance gas paths such as aggregate-filled symmetry trenches positioned within the landfill and surrounding, at least partially, the primary collection zone. The symmetry trenches may be connected to the system's low-pressure source to serve as secondary collectors. A sensing trench positioned within the landfill along the periphery of the collector's zone of influence can be used to monitor the collector pressure and to automatically maintain it at a safe level. The sensing trench can also serve as a secondary equalizing path in heterogeneous landfills. Hot spots may advantageously be tapped by auxiliary collectors whose pressure level bears a predetermined proportional relationship to the primary collector pressure.

  4. 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

  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. 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. PMID:26922087

  7. 40 CFR Table Hh-3 to Subpart Hh of... - Landfill Gas Collection Efficiencies

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills Pt... Description Landfill Gas Collection Efficiency A1: Area with no waste in-place Not applicable; do not use...

  8. Landfill gas application development of the Caterpillar G3600 spark-ignited gas engine

    SciTech Connect

    Mueller, G.P.

    1995-10-01

    A G3600 engine was developed to operate on landfill gas to demonstrate engine performance and identify any operational problems caused by this application. Fuel system and engine performance development were completed using simulated landfill gas containing carbon dioxide and natural gas at the Caterpillar Technical Center. The engine was packaged as a generator set and has operated for 12,000 hours on landfill gas. Engine performance goals similar to those for G3600 natural gas applications were achieved during development and were attained during the field test. Development work and field test endurance results are presented in this paper.

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (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 Efficiencies... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Landfill Gas Collection...

  10. 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).

  11. Evaluation of Fresh Kills landfill gas for industrial applications. Final report, August 1977-March 1980

    SciTech Connect

    Briceland, C.; Bortz, S.; Khinkis, M.J.; Abassi, H.; Waibel, R.T.

    1980-03-01

    This report describes a combined laboratory and field test program carried out at the Fresh Kills Landfill on Staten Island to determine the acceptability of landfill gas as a replacement for natural gas and imported fuels in industrial processes. Landfill gas, created by the natural breakdown of organic materials, is about 50 percent methane. The Fresh Kills gas was tested to gauge its performance, characteristics and heat value, especially in relation to natural gas. The result of the tests were so favorable, that an aggressive program has been initiated statewide to identify landfill sites and potential industrial users for the landfill gas.

  12. 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 ...

  13. 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...

  14. LANDFILL GAS UTILIZATION - DATABASE OF NORTH AMERICAN PROJECTS

    EPA Science Inventory

    The paper summarizes data in an updated and expanded database for North American landfill-gas (LFG)-to-energy projects. t provides summary statistics, including a list of current projects, trends in conversion technologies, and a list of major developers, energy equipment supplie...

  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. Lateral migration and offsite surface emission of landfill gas at City of Montreal Landfill Site.

    PubMed

    Franzidis, Jean-Pierre; Héroux, Martin; Nastev, Miroslav; Guy, Christophe

    2008-04-01

    An evaluation of lateral landfill gas migration was carried out at the Saint-Michel Environmental Complex in Montreal, City of Montreal Landfill Site, Canada, between 2003 and 2005. Biogas concentration measurements and gas-pumping tests were conducted in multilevel wells installed in the backfilled overburden beside the landfill site. A migration event recorded in autumn 2004 during the maintenance shutdown of the extraction system was simulated using TOUGH-LGM software. Eleven high-density instantaneous surface monitoring (ISM) surveys of methane were conducted on the test site. Gas fluxes were calculated by geostatistical analyses of ISM data correlated to dynamic flux chamber measurements. Variograms using normal transformed data showed good structure, and kriged estimates were much better than inverse distance weighting, due to highly skewed data. Measurement-based estimates of yearly off-site surface emissions were two orders of magnitude higher than modelled advective lateral methane flux. Nucleodensimeter measurements of the porosity were abnormally high, indicating that the backfill was poorly compacted. Kriged porosity maps correlated well with emission maps and areas with vegetation damage. Pumping tests analysis revealed that vertical permeability was higher than radial permeability. All results suggest that most of the lateral migration and consequent emissions to the atmosphere were due to the existence of preferential flow paths through macropores. In December 2006, two passively vented trenches were constructed on the test site. They were successful in countering lateral migration. PMID:18578151

  17. 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.

  18. 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

  19. 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...

  20. Negotiating the sale and purchase of landfill gas

    SciTech Connect

    Opdahl, C.D.

    1995-08-01

    This paper discusses many of the business and legal issues which may be encountered in negotiating an agreement for the sale and purchase of landfill gas. A landfill gas sale and purchase contract is really three different agreements wrapped up into one. First, it is a purchase agreement. As a purchase agreement it specifies the parties` obligations about the quantity and quality of the commodity being purchased and sold. It also sets forth the price to be paid for the commodity, payment terms, warranty provisions, indemnification obligations and other matters commonly found in purchase and sale transactions. Second, a landfill gas sale and purchase agreement is a construction agreement. As a construction agreement it obligates the parties to each construct a facility, one facility to collect the gas and the other to generate electricity from consumption of the gas. It also should require the construction of the projects in accordance with approved plans and specifications, in a timely manner and in accordance with applicable laws and ordinances. Third, a landfill gas sale and purchase agreement is a lease or easement agreement. As a lease or easement agreement it requires one party to grant use of a portion of its property to the other party. Also, it sets out the circumstances which will allow landowner to extinguish the right to use or occupy its property, as well as any rights of the land user to maintain or have rights to access to the property and any rights of first refusal. In certain instances it might provide for the grant of security interests as to one of the party`s assets or the entire facility. This paper discusses how these three types of agreements are combined in a single agreement.

  1. Impact of using high-density polyethylene geomembrane layer as landfill intermediate cover on landfill gas extraction.

    PubMed

    Chen, Zezhi; Gong, Huijuan; Zhang, Mengqun; Wu, Weili; Liu, Yu; Feng, Jin

    2011-05-01

    Clay is widely used as a traditional cover material for landfills. As clay becomes increasingly costly and scarce, and it also reduces the storage capacity of landfills, alternative materials with low hydraulic conductivity are employed. In developing countries such as China, landfill gas (LFG) is usually extracted for utilization during filling stage, therefore, the intermediate covering system is an important part in a landfill. In this study, a field test of LFG extraction was implemented under the condition of using high-density polyethylene (HDPE) geomembrane layer as the only intermediate cover on the landfill. Results showed that after welding the HDPE geomembranes together to form a whole airtight layer upon a larger area of landfill, the gas flow in the general pipe increased 25% comparing with the design that the HDPE geomembranes were not welded together, which means that the gas extraction ability improved. However as the heat isolation capacity of the HDPE geomembrane layer is low, the gas generation ability of a shallow landfill is likely to be weakened in cold weather. Although using HDPE geomembrane layer as intermediate cover is acceptable in practice, the management and maintenance of it needs to be investigated in order to guarantee its effective operation for a long term. PMID:21232931

  2. 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

  3. 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

  4. Migration behavior of landfill leachate contaminants through alternative composite liners.

    PubMed

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

    2011-08-01

    Four identical pilot-scale landfill reactors with different alternative composite liners were simultaneously operated for a period of about 540 days to investigate and to simulate the migration behaviors of 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 heavy metals (Pb, Cu, Zn, Cr, Cd, Ni) from landfill leachate to the groundwater. Alternative landfill liners of four reactors consist of R1: Compacted clay liner (10 cm+10 cm, k=10(-8)m/sn), R2: Geomembrane (2 mm HDPE)+compacted clay liner (10 cm+10 cm, k=10⁻⁸ m/sn), R3: Geomembrane (2 mm HDPE)+compacted clay liner (10 cm, k=10⁻⁸ m/sn)+bentonite liner (2 cm)+compacted clay liner (10 cm, k=10⁻⁸ m/sn), and R4: Geomembrane (2 mm HDPE)+compacted clay liner (10 cm, k=10⁻⁸ m/sn)+zeolite liner (2 cm)+compacted clay liner (10 cm, k=10⁻⁸ m/sn). Wastes representing Istanbul municipal solid wastes were disposed in the reactors. To represent bioreactor landfills, reactors were operated by leachate recirculation. To monitor and control anaerobic degradation in the reactors, variations of conventional parameters (pH, alkalinity, chloride, conductivity, COD, TOC, TKN, ammonia and alcaly metals) were also investigated in landfill leachate samples. The results of this study showed that about 35-50% of migration of organic contaminants (phenolic compounds) and 55-100% of migration of inorganic contaminants (heavy metals) to the model groundwater could be effectively reduced with the use of bentonite and zeolite materials in landfill liner systems. Although leachate contaminants can reach to the groundwater in trace concentrations, findings of this study concluded that the release of these compounds from landfill leachate to the groundwater may potentially be of an important environmental concern based on the experimental findings. PMID:21621822

  5. 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

  6. 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.

  7. 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

  8. 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. PMID:20124321

  9. 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...

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

    PubMed

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

    2012-12-01

    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 landfill covers. PMID:22884579

  11. 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.

  12. 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. PMID:26211632

  13. Landfill gas cleanup for carbonate fuel cell power generation. Final report

    SciTech Connect

    Steinfield, G.; Sanderson, R.

    1998-02-01

    Landfill gas represents a significant fuel resource both in the US and worldwide. The emissions of landfill gas from existing landfills has become an environmental liability contributing to global warming and causing odor problems. Landfill gas has been used to fuel reciprocating engines and gas turbines, and may also be used to fuel carbonate fuel cells. Carbonate fuel cells have high conversion efficiencies and use the carbon dioxide present in landfill gas as an oxidant. There are, however, a number of trace contaminants in landfill gas that contain chlorine and sulfur which are deleterious to fuel cell operation. Long-term economical operation of fuel cells fueled with landfill gas will, therefore, require cleanup of the gas to remove these contaminants. The overall objective of the work reported here was to evaluate the extent to which conventional contaminant removal processes could be combined to economically reduce contaminant levels to the specifications for carbonate fuel cells. A pilot plant cleaned approximately 970,000 scf of gas over 1,000 hours of operation. The testing showed that the process could achieve the following polished gas concentrations: less than 80 ppbv hydrogen sulfide; less than 1 ppmv (the detection limit) organic sulfur; less than 300 ppbv hydrogen chloride; less than 20--80 ppbv of any individual chlorinated hydrocarbon; and 1.5 ppm sulfur dioxide.

  14. Spatial variability of soil gas concentration and methane oxidation capacity in landfill covers.

    PubMed

    Röwer, Inga Ute; Geck, Christoph; Gebert, Julia; Pfeiffer, Eva-Maria

    2011-05-01

    In order to devise design criteria for biocovers intended to enhance the microbial oxidation of landfill methane it is critical to understand the factors influencing gas migration and methane oxidation in landfill cover soils. On an old municipal solid waste landfill in north-western Germany soil gas concentrations (10, 40, 90 cm depth), topsoil methane oxidation capacity and soil properties were surveyed at 40 locations along a 16 m grid. As soil properties determine gas flow patterns it was hypothesized that the variability in soil gas composition and the subsequent methanotrophic activity would correspond to the variability of soil properties. Methanotrophic activity was found to be subject to high spatial variability, with values ranging between 0.17 and 9.80 g CH(4)m(-2)h(-1)(.) Considering the current gas production rate of 0.03 g CH(4)m(-2)h(-1), the oxidation capacity at all sampled locations clearly exceeded the flux to the cover, and can be regarded as an effective instrument for mitigating methane fluxes. The methane concentration in the cover showed a high spatial heterogeneity with values between 0.01 and 0.32 vol.% (10 cm depth), 22.52 vol.% (40 cm), and 36.85 vol.% (90 cm). The exposure to methane raised the oxidation capacity, suggested by a statistical correlation to an increase in methane concentration at 90 cm depth. Methane oxidation capacity was further affected by the methanotroph bacteria pH optimum and nutrient availability, and increased with decreasing pH towards neutrality, and increased with soluble ion concentration). Soil methane and carbon dioxide concentration increased with lower flow resistance of the cover, as represented by the soil properties of a reduced bulk density, increase in air capacity and in relative ground level. PMID:20943363

  15. Measured gas emissions from four landfills in south africa and some implications for landfill design and methane recovery in semi-arid climates.

    PubMed

    Fourie, A B; Morris, J W F

    2004-12-01

    The magnitude of annual global emissions of methane from municipal solid waste landfills without landfill gas control systems implies that these landfills are significant contributors to the atmospheric load of greenhouse gases. There have been a number of field studies undertaken internationally to measure actual fluxes of methane and carbon dioxide from landfills, with a view to corroborating modelled predictions of the contribution of landfills to the global greenhouse gas budget. The vast majority of these studies have been undertaken in more temperate climates and in developed countries. This paper reports a study of landfill gas emissions from four large landfills located in the semi-arid interior of South Africa. A static accumulation chamber was used and measurements were made at each site over a period of two to three days. The results were analysed by three different methods, all of them leading to the same general conclusion that landfill gas emission rates were lower than expected. A common conclusion based on results from all four sites was that capping of landfills in semi-arid climates with low permeability covers would probably significantly retard the already low rate of waste degradation and thus gas generation. While this may be regarded as advantageous in the short term, it cannot be relied upon in perpetuity as clayey landfill covers will inevitably desiccate and crack in a semiarid environment. In addition, reasonable after-care periods for such landfills are likely to extend well beyond the currently stipulated 30-year period, and efforts to encourage energy recovery from landfills may be hampered because gas generation rates decrease as the waste dries out under conditions of minimal recharge from precipitation. A landfill cover that allows small amounts of percolation of rainfall into the waste may therefore in fact be beneficial in semiarid climates, although care would need to be taken to carefully regulate this infiltration. PMID

  16. 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.

  17. Gas chromatographic determination of trace amounts of vinyl chloride and dichloroethenes in landfill-gas.

    PubMed

    Wittsiepe, J; Selenka, F; Jackwerth, E

    1996-03-01

    A method for the determination of vinyl chloride (VC) and dichloroethenes (DCE) in gas samples is presented. The analytes are preconcentrated from a gas-volume of up to 20 l on an adsorption tube filled with 1.0 g of a carbon molecular sieve at a flow rate of 80 l/h and are subsequently desorbed with carbon disulfide. Vinyl bromide is added as internal standard to the extract. The analytes are determined as their 1,2-dibromo-derivatives by capillary gas chromatography with electron capture detection. The detection limits have been found to be 82 ng/m(3) = 32 ppt (VC), 190 ng/m(3) = 48 ppt (1,1-DCE) and 96 ng/m(3) = 24 ppt (cis-/trans-1,2-DCE). The method has been used for the quantification of the anaerobic microbial degradation of tetra- (PCE) and trichloroethene (TCE) to dichloroethenes and vinyl chloride in landfill sites. The substances have been analyzed in landfill-gas as well as in gaseous emissions from the landfill surface. The mean emission rates of tetrachloroethene, trichloroethene and vinyl chloride from the landfill surface into the ambient air are about 0.5 microg/(m(2) x h). PMID:15048415

  18. 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

  19. 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.

  20. 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...

  1. Tracer method to measure landfill gas emissions from leachate collection systems.

    PubMed

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

    2010-11-01

    This paper describes a method developed for quantification of gas emissions from the leachate collection system at landfills and present emission data measured at two Danish landfills with no landfill gas collection systems in place: Fakse landfill and AV Miljø. Landfill top covers are often designed to prevent infiltration of water and thus are made from low permeable materials. At such sites a large part of the gas will often emit through other pathways such as the leachate collection system. These point releases of gaseous constituents from these locations cannot be measured using traditional flux chambers, which are often used to measure gas emissions from landfills. Comparing tracer measurements of methane (CH(4)) emissions from leachate systems at Fakse landfill and AV Miljø to measurements of total CH(4) emissions, it was found that approximately 47% (351 kg CH(4) d(-1)) and 27% (211 kg CH(4) d(-1)), respectively, of the CH(4) emitting from the sites occurred from the leachate collection systems. Emission rates observed from individual leachate collection wells at the two landfills ranged from 0.1 to 76 kg CH(4) d(-1). A strong influence on emission rates caused by rise and fall in atmospheric pressure was observed when continuously measuring emission from a leachate well over a week. Emission of CH(4) was one to two orders of magnitude higher during periods of decreasing pressure compared to periods of increasing pressure. PMID:20378325

  2. 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...

  3. 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}.

  4. 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.

  5. Thermal inactivation of Bacillus anthracis surrogate spores in a bench-scale enclosed landfill gas flare.

    PubMed

    Tufts, Jenia A McBrian; Rosati, Jacky A

    2012-02-01

    A bench-scale landfill flare system was designed and built to test the potential for landfilled biological spores that migrate from the waste into the landfill gas to pass through the flare and exit into the environment as viable. The residence times and temperatures of the flare were characterized and compared to full-scale systems. Geobacillus stearothermophilus and Bacillus atrophaeus, nonpathogenic spores that may serve as surrogates for Bacillus anthracis, the causative agent for anthrax, were investigated to determine whether these organisms would be inactivated or remain viable after passing through a simulated landfill flare. High concentration spore solutions were aerosolized, dried, and sent through a bench-scale system to simulate the fate of biological weapon (BW)-grade spores in a landfill gas flare. Sampling was conducted downstream of the flare using a bioaerosol collection device containing sterile white mineral oil. The samples were cultured, incubated for seven days, and assessed for viability. Results showed that the bench-scale system exhibited good similarity to the real-world conditions of an enclosed standard combustor flare stack with a single orifice, forced-draft diffusion burner. All spores of G. stearothermophilus and B. atrophaeus were inactivated in the flare, indicating that spores that become re-entrained in landfill gas may not escape the landfill as viable, apparently becoming completely inactivated as they exit through a landfill flare. PMID:22442931

  6. 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

  7. 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...

  8. 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.

  9. 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

  10. No pain-no gain, the evolution of a landfill gas project

    SciTech Connect

    Morford, K.L.

    1995-08-01

    After the City`s utility department closed down an on-site landfill gas (LFG) fired electrical generating facility for permitting problems, and shortly thereafter suffered a traumatic experience with a leaking and inefficient gas collection system, the development of another landfill gas project in the City of Glendale was not a safe thought to harbor. Yet, in 1990, Glendale was approached by several persistent developers who convinced the City to explore another, but larger gas project. Scholl Canyon Landfill, owned principally by the City of Glendale, is a moderately sized facility with 22 million tons of refuse in place and a 12 million ton remaining capacity. The site is comprised of two separate adjoining canyons totalling 410 acres. The smaller canyon is no longer active and today supports a privately operated golf course and driving range. While the active site is within Glendale, the landfill has split ownership with Glendale retaining an 83 percent share, Los Angeles County 10 percent and Southern California Edison 7 percent. Landfill operations are managed by the Los Angeles County Sanitation Districts (LACSD) in accordance with a joint powers agreement that originated in the early 1960`s. Generating approximately 9 million cubic feet of landfill gas per day with a heating value about one-third that of natural gas, private developers could envision a lucrative project, particularly considering the availability of Federal tax credits for producing fuel from a non-conventional source. The evolution of the Glendale project is described in this paper.

  11. 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. PMID:22796013

  12. 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.

  13. Landfill Methane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Landfill methane (CH4) accounts for approximately 1.3% (0.6 Gt) of global anthropogenic greenhouse gas emissions relative to total emissions from all sectors of about 49 Gt CO2-eq yr-1. For countries with a history of controlled landfilling, landfills can be one of the larger national sources of ant...

  14. 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. PMID:15736343

  15. 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.

  16. 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

  17. 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 ...

  18. Methane mass balance at three landfill sites: what is the efficiency of capture by gas collection systems?

    PubMed

    Spokas, K; Bogner, J; Chanton, J P; Morcet, M; Aran, C; Graff, C; Golvan, Y Moreau-Le; Hebe, I

    2006-01-01

    Many developed countries have targeted landfill methane recovery among greenhouse gas mitigation strategies, since methane is the second most important greenhouse gas after carbon dioxide. Major questions remain with respect to actual methane production rates in field settings and the relative mass of methane that is recovered, emitted, oxidized by methanotrophic bacteria, laterally migrated, or temporarily stored within the landfill volume. This paper presents the results of extensive field campaigns at three landfill sites to elucidate the total methane balance and provide field measurements to quantify these pathways. We assessed the overall methane mass balance in field cells with a variety of designs, cover materials, and gas management strategies. Sites included different cell configurations, including temporary clay cover, final clay cover, geosynthetic clay liners, and geomembrane composite covers, and cells with and without gas collection systems. Methane emission rates ranged from -2.2 to >10,000 mg CH(4) m(-2) d(-1). Total methane oxidation rates ranged from 4% to 50% of the methane flux through the cover at sites with positive emissions. Oxidation of atmospheric methane was occurring in vegetated soils above a geomembrane. The results of these studies were used as the basis for guidelines by the French environment agency (ADEME) for default values for percent recovery: 35% for an operating cell with an active landfill gas (LFG) recovery system, 65% for a temporary covered cell with an active LFG recovery system, 85% for a cell with clay final cover and active LFG recovery, and 90% for a cell with a geomembrane final cover and active LFG recovery. PMID:16198554

  19. Methane mass balance at three landfill sites: What is the efficiency of capture by gas collection systems?

    SciTech Connect

    Spokas, K. . E-mail: spokas@morris.ars.usda.gov; Bogner, J.; Chanton, J.P.; Morcet, M.; Aran, C.; Graff, C.; Golvan, Y. Moreau-Le; Hebe, I.

    2006-07-01

    Many developed countries have targeted landfill methane recovery among greenhouse gas mitigation strategies, since methane is the second most important greenhouse gas after carbon dioxide. Major questions remain with respect to actual methane production rates in field settings and the relative mass of methane that is recovered, emitted, oxidized by methanotrophic bacteria, laterally migrated, or temporarily stored within the landfill volume. This paper presents the results of extensive field campaigns at three landfill sites to elucidate the total methane balance and provide field measurements to quantify these pathways. We assessed the overall methane mass balance in field cells with a variety of designs, cover materials, and gas management strategies. Sites included different cell configurations, including temporary clay cover, final clay cover, geosynthetic clay liners, and geomembrane composite covers, and cells with and without gas collection systems. Methane emission rates ranged from -2.2 to >10,000 mg CH{sub 4} m{sup -2} d{sup -1}. Total methane oxidation rates ranged from 4% to 50% of the methane flux through the cover at sites with positive emissions. Oxidation of atmospheric methane was occurring in vegetated soils above a geomembrane. The results of these studies were used as the basis for guidelines by the French environment agency (ADEME) for default values for percent recovery: 35% for an operating cell with an active landfill gas (LFG) recovery system, 65% for a temporary covered cell with an active LFG recovery system, 85% for a cell with clay final cover and active LFG recovery, and 90% for a cell with a geomembrane final cover and active LFG recovery.

  20. 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.

  1. [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

  2. 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.

  3. 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

  4. Chemical composition and genotoxicity assessment of sanitary landfill leachate from Rovinj, Croatia.

    PubMed

    Gajski, Goran; Oreščanin, Višnja; Garaj-Vrhovac, Vera

    2012-04-01

    Chemical analysis and an in vitro approach were performed to assess elemental composition and genotoxic effects of the samples of landfill leachate taken from Lokva Vidotto sanitary landfill the official landfill for Rovinj town, Croatia. Two samples of landfill leachate were collected and analyzed in order to evaluate macro, micro and trace elements by atomic absorption spectroscopy, energy dispersive X-ray spectrometry and colorimetry. Genotoxicity of sanitary landfill leachate was evaluated in human lymphocytes by the use of the micronucleus test and comet assay. Samples were characterized with relatively low concentrations of heavy metals while organic component level exceeded upper permissible limit up to 39 times. Observed genotoxic effects should be connected with high concentrations of ammonia nitrogen, which exceeded permissible limit up to 180 times. Leachate samples of both sanitary landfills increased the frequency of micronuclei, nucleoplasmic bridges and nuclear buds. Increase of DNA damage in human lymphocytes was also detected by virtue of measuring comet assay parameters. All parameters showed statistically significant difference compared to negative control. Increased micronucleus and comet assay parameters indicate that both samples of sanitary landfill leachate are genotoxic and could pose environmental and human health risk if discharged to an aquatic environment. PMID:22177983

  5. Gas Transport Parameters for Landfill Final Cover Soil: Measurements and Model Modification by Dry Bulk Density

    NASA Astrophysics Data System (ADS)

    Wickramarachchi, P. N.; Kawamoto, K.; Hamamoto, S.; Nagamori, M.; Moldrup, P.; Komatsu, T.

    2011-12-01

    Landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric methane (CH4). Until recently, landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest sources of anthropogenic CH4 emission, the final cover system should also be designed for minimizing the greenhouse gases migration into the atmosphere or the areas surrounding the landfill while securing the hydraulic performance. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil, few studies about gas transport characteristics of landfill cover soils have been done. However, recent soil-gas studies implied that the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size are key parameters to understand landfill gaseous performance. 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 particle size fraction effects on ka and Dp for landfill final cover soil was investigated. The disturbed soil samples were taken from landfill final cover in Japan. 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, 2120 cm3) at two different compaction levels [(MP):2700 kN/m2 and (SP):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 of 0.98, 2.94, 9.81, 1235 kPa and with air-dried and oven-dried conditions. Results showed that measured Dp and ka values for the

  6. 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. his phase consisted primarily of the construction and testing of a Gas Pretreatment Unit (GPU) whose function is to remove those impur...

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

    PubMed

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

    2012-02-01

    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(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. PMID:21996285

  8. 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...

  9. Transport and reaction processes affecting the attenuation of landfill gas in cover soils.

    PubMed

    Molins, S; Mayer, K U; Scheutz, C; Kjeldsen, P

    2008-01-01

    Methane and trace organic gases produced in landfill waste are partly oxidized in the top 40 cm of landfill cover soils under aerobic conditions. The balance between the oxidation of landfill gases and the ingress of atmospheric oxygen into the soil cover determines the attenuation of emissions of methane, chlorofluorocarbons, and hydrochlorofluorocarbons to the atmosphere. This study was conducted to investigate the effect of oxidation reactions on the overall gas transport regime and to evaluate the contributions of various gas transport processes on methane attenuation in landfill cover soils. For this purpose, a reactive transport model that includes advection and the Dusty Gas Model for simulation of multicomponent gas diffusion was used. The simulations are constrained by data from a series of counter-gradient laboratory experiments. Diffusion typically accounts for over 99% of methane emission to the atmosphere. Oxygen supply into the soil column is driven exclusively by diffusion, whereas advection outward offsets part of the diffusive contribution. In the reaction zone, methane consumption reduces the pressure gradient, further decreasing the significance of advection near the top of the column. Simulations suggest that production of water or accumulation of exopolymeric substances due to microbially mediated methane oxidation can significantly reduce diffusive fluxes. Assuming a constant rate of methane production within a landfill, reduction of the diffusive transport properties, primarily due to exopolymeric substance production, may result in reduced methane attenuation due to limited O(2) -ingress. PMID:18268309

  10. 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.

  11. Invisible threat: Odors and landfill gas from construction and demolition waste

    SciTech Connect

    Flynn, B.E.

    1998-01-01

    It once was thought that construction and demolition (C and D) waste used as clean fill and landfill cover would generate little or no gas or odors. Previous experience with municipal solid waste (MSW) traditionally generated odors of a few parts per million (ppm) up to maybe 100 ppm of hydrogen sulfide (H{sub 2}S) in the landfill gas formed. However, people are slowly becoming aware of the tremendous amount of sulfide generated by the latest C and D waste processing practices. C and D waste can generate up to 20,000--30,000 ppm (2--3%) average concentrations of H{sub 2}S. The hottest wells have been measured with as much as 8% H{sub 2}S in the landfill gas.

  12. 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

  13. 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...

  14. Soil-gas contamination and entry of volatile organic compounds into a house near a landfill

    SciTech Connect

    Hodgson, A.T.; Garbesi, K.; Sextro, R.G.; Daisey, J.M. )

    1992-03-01

    Toxic volatile organic compounds (VOC) are commonly found in landfills, including those accepting only municipal waste. These VOC can migrate away from the site through the soil and result in contaminated off-site soil gas. This contaminated soil gas can enter houses built near landfills and is a potential source of human exposure to VOC. This study investigated soil-gas contamination and the mechanisms of entry of VOC into a house with a basement sited adjacent to a municipal landfill. The VOC were identified and quantified in the soil gas and in indoor and outdoor air. Pressure coupling between the basement and the surrounding soil was measured. Using soil-gas tracers, the pressure-driven advective entry of soil gas was quantified as a function of basement depressurization. From the measurements, estimates were made for the diffusive and advective entry rates of VOC into the house. A comparison of the chlorinated hydrocarbons found in soil gas at the site and in the landfill suggests that the landfill is the source of the halogenated compounds in the vicinity of the house. At the conditions of the study, the diffusive and advective entry rates of VOC from soil into the basement were estimated to be low and of similar magnitude. Advective entry of soil gas into the house was limited by the low soil air permeability and the low below-grade leakage area of the basement. For this reason, high indoor concentrations due to the intrusion of VOC from soil gas are unlikely at this house, even under conditions that would produce relatively large underpressures in the basement.

  15. Landfill Gas Emissions Model, version 2.0., user`s manual. Final report, September 1993--September 1997

    SciTech Connect

    Pelt, R.; Bass, R.; Heaton, R.; White, C.; Blackard, A.

    1998-05-01

    Landfill Gas Emissions Model (LandGEM) estimates air pollutant emissions from municipal solid waste (MSW) landfills. The model can be used to estimate emission rates for methane, carbon dioxide, nonmethane organic compounds, and individual air pollutants from landfills. It can also be used by landfill owners and operators to determine if a landfill is subject to the control requirements of the federal New Source Performance Standard (NSPS) for new MSW landfills or the emission guidelines for existing MSW landfills. The model is based on a first order decay equation and can be run using site-specific data are available, using default values: one set based on the requirements of the NSPS and emission guidelines, and the other based on emission factors in EPA`s Compilation of Air Pollutant Emission Factors, AP-42.

  16. 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. PMID:23200403

  17. 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.

  18. 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...

  19. A CASE STUDY OF THE LOS ANGELES COUNTY PALOS VERDES LANDFILL GAS DEVELOPMENT PROJECT

    EPA Science Inventory

    This report documents the first-ever-attempt to capture sanitary landfill gases and beneficiate them to natural gas pipeline quality--or very nearly so. For this reason the authors must credit the entrepreneurs for a successful first full-scale demonstration of a technology that ...

  20. 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...

  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. 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...

  3. 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...

  4. 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. PMID:23063306

  5. Can soil gas profiles be used to assess microbial CH4 oxidation in landfill covers?

    PubMed

    Gebert, Julia; Röwer, Inga Ute; Scharff, Heijo; Roncato, Camila D L; Cabral, Alexandre R

    2011-05-01

    A method is proposed to estimate CH(4) oxidation efficiency in landfill covers, biowindows or biofilters from soil gas profile data. The approach assumes that the shift in the ratio of CO(2) to CH(4) in the gas profile, compared to the ratio in the raw landfill gas, is a result of the oxidation process and thus allows the calculation of the cumulative share of CH(4) oxidized up to a particular depth. The approach was validated using mass balance data from two independent laboratory column experiments. Values corresponded well over a wide range of oxidation efficiencies from less than 10% to nearly total oxidation. An incubation experiment on 40 samples from the cover soil of an old landfill showed that the share of CO(2) from respiration falls below 10% of the total CO(2) production when the methane oxidation capacity is 3.8 μg CH(4)g(dw)(-1)h(-1) or higher, a rate that is often exceeded in landfill covers and biofilters. The method is mainly suitable in settings where the CO(2) concentrations are not significantly influenced by processes such as respiration or where CH(4) loadings and oxidation rates are high enough so that CO(2) generated from CH(4) oxidation outweighs other sources of CO(2). The latter can be expected for most biofilters, biowindows and biocovers on landfills. This simple method constitutes an inexpensive complementary tool for studies that require an estimation of the CH(4) oxidation efficiency values in methane oxidation systems, such as landfill biocovers and biowindows. PMID:21074981

  6. Development of correction factors for landfill gas emission model suiting Indian condition to predict methane emission from landfills.

    PubMed

    Sil, Avick; Kumar, Sunil; Wong, Jonathan W C

    2014-09-01

    Methane emission from landfill gas emission (LandGEM) model was validated through the results of laboratory scale biochemical methane potential assay. Results showed that LandGEM model over estimates methane (CH4) emissions; and the true CH4 potential of waste depends on the level of segregation. Based on these findings, correction factors were developed to estimate CH4 emission using LandGEM model especially where the level of segregation is negligible or does not exist. The correction factors obtained from the study were 0.94, 0.13 and 0.74 for food waste, mixed un-segregated municipal solid waste (MSW) and vegetable wastes, respectively. PMID:24685512

  7. 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.

  8. 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...

  9. 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

  10. Regional prediction of long-term landfill gas to energy potential.

    PubMed

    Amini, Hamid R; Reinhart, Debra R

    2011-01-01

    Quantifying landfill gas to energy (LFGTE) potential as a source of renewable energy is difficult due to the challenges involved in modeling landfill gas (LFG) generation. In this paper a methodology is presented to estimate LFGTE potential on a regional scale over a 25-year timeframe with consideration of modeling uncertainties. The methodology was demonstrated for the US state of Florida, as a case study, and showed that Florida could increase the annual LFGTE production by more than threefold by 2035 through installation of LFGTE facilities at all landfills. The estimated electricity production potential from Florida LFG is equivalent to removing some 70 million vehicles from highways or replacing over 800 million barrels of oil consumption during the 2010-2035 timeframe. Diverting food waste could significantly reduce fugitive LFG emissions, while having minimal effect on the LFGTE potential; whereas, achieving high diversion goals through increased recycling will result in reduced uncollected LFG and significant loss of energy production potential which may be offset by energy savings from material recovery and reuse. Estimates showed that the power density for Florida LFGTE production could reach as high as 10 Wm(-2) with optimized landfill operation and energy production practices. The environmental benefits from increased lifetime LFG collection efficiencies magnify the value of LFGTE projects. PMID:21703844

  11. 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.

  12. SALE OF SURPLUS DIGESTER AND LANDFILL GAS TO PUBLIC UTILITIES

    EPA Science Inventory

    Methane gas produced by anaerobic digestion of wastewater sludge can be upgraded to pipeline quality and sold to a public utility for injection into a natural gas distribution system. Upgrading the gas typically involves treatment for removal of carbon dioxide and hydrogen sulfid...

  13. Landfill gas generation after mechanical biological treatment of municipal solid waste. Estimation of gas generation rate constants.

    PubMed

    Gioannis, G De; Muntoni, A; Cappai, G; Milia, S

    2009-03-01

    Mechanical biological treatment (MBT) of residual municipal solid waste (RMSW) was investigated with respect to landfill gas generation. Mechanically treated RMSW was sampled at a full-scale plant and aerobically stabilized for 8 and 15 weeks. Anaerobic tests were performed on the aerobically treated waste (MBTW) in order to estimate the gas generation rate constants (k,y(-1)), the potential gas generation capacity (L(o), Nl/kg) and the amount of gasifiable organic carbon. Experimental results show how MBT allowed for a reduction of the non-methanogenic phase and of the landfill gas generation potential by, respectively, 67% and 83% (8 weeks treatment), 82% and 91% (15 weeks treatment), compared to the raw waste. The amount of gasified organic carbon after 8 weeks and 15 weeks of treatment was equal to 11.01+/-1.25kgC/t(MBTW) and 4.54+/-0.87kgC/t(MBTW), respectively, that is 81% and 93% less than the amount gasified from the raw waste. The values of gas generation rate constants obtained for MBTW anaerobic degradation (0.0347-0.0803y(-1)) resemble those usually reported for the slowly and moderately degradable fractions of raw MSW. Simulations performed using a prediction model support the hypothesis that due to the low production rate, gas production from MBTW landfills is well-suited to a passive management strategy. PMID:18954969

  14. 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 ...

  15. 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

  16. 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

  17. 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

  18. 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.

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

    PubMed

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

    2011-05-01

    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. PMID:20888746

  20. 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

  1. 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

  2. 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

  3. 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

  4. Two years of operation completed for large landfill gas power plant

    SciTech Connect

    Mullins, P.

    1994-10-01

    The V16 GEC Alsthom Ruston Diesels RK270GS engine, one of the largest lean-burn, spark-ignited engines running on landfill gas anywhere in the world, has just completed its second year of commercial operation at the Calvert landfill site. It has developed 2.8 MW at 1000 r/min and drives a Brush air-cooled alternator, feeding electricity at 11 kV into the area grid 24 hours a day. The site has already taken some seven million tonnes of waste and will eventually absorb around 20 million over a projected life of 20-30 years. By that time, electrical output from the site should amount to about 13 MW. 3 figs.

  5. Determination of siloxanes and VOC in landfill gas and sewage gas by canister sampling and GC-MS/AES analysis

    SciTech Connect

    Schweigkofler, M.; Niessner, R.

    1999-10-15

    Biogases such as landfill gas and sewage gas undergo a combustion process which is generating electric energy. Since several trace compounds such as siloxanes (also halogenated and sulfur compounds) are known to cause severe problems to these gas combustion engines, they are of particular interest. In this work, a new technique for sampling, identification, and quantification of siloxanes and volatile organic carbon (VOC) in landfill gas and sewage gas is presented. After sample collection using evacuated stainless steel canisters biogas was analyzed by gas chromatography-mass spectrometry/atomic emission spectroscopy (GC-MS/AES). Using gas canisters, the sampling process was simplified (no vacuum pump needed), and multiple analysis was possible. The simultaneous application of MSD and AED allowed a rapid screening of silicon compounds in the complex biogases. Individual substances were identified independently both by MSD analysis and by determination of their elemental constitution. Quantification of trace compounds was achieved using a 30 component external standard containing siloxanes, organochlorine and organosulfur compounds, alkanes, terpenes, and aromatic compounds. Precision, linearity, and detection limits have been studied. In real samples, concentrations of silicon containing compounds (trimethylsilanol, hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasilioxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane) in the mg/m{sub 3} range have been observed.

  6. 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.

  7. Distribution and Composition of Microbial Populations in a Landfill Leachate Contaminated Aquifer (Grindsted, Denmark).

    PubMed

    Ludvigsen; Albrechtsen; Ringelberg; Ekelund; Christensen

    1999-04-01

    > Abstract To investigate whether landfill leachates affected the microbial biomass and/or community composition of the extant microbiota, 37 samples were collected along a 305-m transect of a shallow landfill-leachate polluted aquifer. The samples were analyzed for total numbers of bacteria by use of the acridine orange direct count method (AODC). Numbers of dominant, specific groups of bacteria and total numbers of protozoa were measured by use of the most probable number method (MPN). Viable biomass estimates were obtained from measures of ATP and ester-linked phospholipid fatty acid (PLFA) concentrations. The estimated numbers of total bacteria by direct counts were relatively constant throughout the aquifer, ranging from a low of 4.8 x 10(6) cells/g dry weight (dw) to a high of 5.3 x 10(7) cells/g dw. Viable biomass estimates based on PLFA concentrations were one to three orders of magnitude lower with the greatest concentrations (up to 4 x 10(5) cells/g dw) occurring at the border of the landfill and in samples collected from thin lenses of clay and silt with sand streaks. Cell number estimates based on ATP concentrations were also found to be lower than the direct count measurements (<2.2 x 10(6) cells/g dw), and with the greatest concentrations close to the landfill. Methanogens (Archaea) and reducers of sulfate, iron, manganese, and nitrate were all observed in the aquifer. Methanogens were found to be restricted to the most polluted and reduced part of the aquifer at a maximum cell number of 5.4 x 10(4) cells/g dw. Populations of sulfate reducers decreased with an increase in horizontal distance from the landfill ranging from a high of 9.0 x 10(3) cells/g dw to a low of 6 cells/g dw. Iron, manganese, and nitrate reducers were detected throughout the leachate plume all at maximum cell numbers of 10(6) cells/g dw. Changes in PLFA profiles indicated that a shift in microbial community composition occurred with increasing horizontal distance from the landfill

  8. 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.

  9. 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.

  10. 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...

  11. Ionic composition and greenhouse gases evaluation in Tietê River sediment and mud landfill

    NASA Astrophysics Data System (ADS)

    La-Scalea, M. A.; Fornaro, A.; Abreu, E. L.; Mendonça, C. A.

    2012-04-01

    There are 39 cities composing the Metropolitan Area of São Paulo (MASP) which has grown seven times during the last sixty years, reaching, in 2011, 19.3 million inhabitants. This fact associated with a strong industrial development provoked, among other consequences, a disordered urbanization along the most important river of the region: Tietê. About 100 Km of its 1,150 Km full extension crosses MASP and, during the 60's, Marginal Tietê roadway was constructed, occupying the river banks as access routes. Tietê River was straightened and several landfills were created with its deposit (sediment and mud). EACH-USP (46.50 W, 23.48 S) lies nowadays in one of these areas, where this work has been developed. Therefore, the goal is to evaluate the chemical composition (ionic and gases) and its variability in function of the depth levels using three wells, from 0.60 to 9.0 m of depth. The wells were perforated in September 2011, end of the dry weather. Each well owns a homemade multiport sampling device (HMSD), being possible to push gas and/or water up from 15 available ports. The gases measurements were carried out using a GEM-2000 plus (Landtec) portable analyzer. Aqueous samples containing solid material were taken at each level depth from ports of the HMSD. However, no water was found in some levels. All samples were kept cooled until analysis procedures. After decantation of the solid material, the supernatant liquid was divided in two portions, being its conductivity (Micronal conductimeter) and pH (pH-meter Metrohm 654 with combined glass electrode) measured with the former and ionic analysis with the latter, in which all samples were filtered (Millex 0.22 micrometer pores) before each ionic chromatographic analysis, using Metrohm 850 System, for the ions: sodium, ammonium, potassium, calcium, magnesium, chloride, nitrate and sulfate. The first sampling stage was carried out during November and December 2011 in the beginning of rainy season in the mid Spring

  12. 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

  13. A new route to financing landfill gas-to-energy projects

    SciTech Connect

    Siever, D.R.

    1995-03-01

    For the last several years, just over half of the nation`s new power capacity has been supplied by private, independent power project developers. Of this, virtually all the projects over 10 megawatts in size have been financed with non-recourse debt - that is, where the lender can look only to cash flows from the project for repayment, rather than to the financial resources of the project developer. This has allowed relatively small, entrepreneurial development companies to compete on an equal footing with much larger companies, including the utilities themselves. But developers of the 140 or so landfill gas projects operating in North America haven`t shared the advantages of these other independent projects. While equity financing for landfill gas projects has been available for some time, most LFG developers have found it extremely difficult to attract non-recourse debt due to the small size and perceived technology/environmental risk of LFG projects. Lenders` attitudes are changing however, and more are looking more favorably at providing non-recourse loans for LFG projects. Fulfilling certain requirements, project developers may be able to qualify for this financing technique.

  14. 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

  15. 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

  16. 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.

  17. 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

  18. 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

  19. Landfill gas cleanup for carbonate fuel cell power generation. CRADA final report

    SciTech Connect

    Steinfeld, G.; Sanderson, R.

    1998-02-01

    The overall objective of the work reported here was to evaluate the extent to which conventional contaminant removal processes could be combined to economically reduce contaminant levels to the specifications for carbonate fuel cells. The technical effort was conducted by EPRI, consultant David Thimsen, Kaltec of Minnesota, Energy Research Corporation (ERC) and Interpoll Laboratories. The Electric Power Research Institute (EPRI) made available two test skids originally used to test an ERC 30 kW carbonate fuel cell at the Destec Coal Gasification Plan in Plaquemine, LA. EPRI`s carbonate fuel cell pilot plant was installed at the Anoka County Regional Landfill in Ramsey, Minnesota. Additional gas cleaning equipment was installed to evaluate a potentially inexpensive, multi-stage gas cleaning process to remove sulfur and chlorine in the gas to levels acceptable for long-term, economical carbonate fuel cell operation. The pilot plant cleaned approximately 970,000 scf (27,500 Nm{sup 3}) of gas over 1,000 hours of operation. The testing showed that the process could achieve the following polished gas concentrations. Less than 80 ppbv hydrogen sulfide; less than 1 ppmv (the detection limit) organic sulfur; less than 300 ppbv hydrogen chloride; less than 20--80 ppbv of any individual chlorined hydrocarbon; and 1.5 ppm sulfur dioxide. These were the detection limits of the analytical procedures employed. It is probable that the actual concentrations are below these analytical limits.

  20. 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...

  1. Assessment of internal condition of waste in a roofed landfill.

    PubMed

    Zhang, Xin; Matsuto, Toshihiko

    2013-01-01

    Recently, roofed landfills have been gaining popularity in Japan. Roofed landfills have several advantages over non-roofed landfills such as eliminating the visibility of waste and reducing the spread of offensive odours. This study examined the moisture balance and aeration conditions, which promote waste stabilisation, in a roofed landfill that included organic waste such as food waste. Moisture balance was estimated using waste characterization and the total amount of landfilled waste. Internal conditions were estimated based on the composition, flux, and temperature of the landfill gas. Finally, in situ aeration was performed to determine the integrity of the semi-aerobic structure of the landfill. With the effects of rainfall excluded, only 15% of the moisture held by the waste was discharged as leachate. The majority of the moisture remained in the waste layer, but was less than the optimal moisture level for biodegradation, indicating that an appropriate water spray should be administered. To assess waste degradation in this semi-aerobic landfill, the concentration and flow rate of landfill gas were measured and an in situ aeration test was performed. The results revealed that aerobic biodegradation had not occurred because of the unsatisfactory design and operation of the landfill. PMID:22989405

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. Review of past research and proposed action plan for landfill gas-to-energy applications in India.

    PubMed

    Siddiqui, Faisal Zia; Zaidi, Sadaf; Pandey, Suneel; Khan, Mohd Emran

    2013-01-01

    Open dumps employed for disposal of municipal solid waste (MSW) are generally referred to as landfills and have been traditionally used as the ultimate disposal method in India. The deposition of MSW in open dumps eventually leads to uncontrolled emission of landfill gas (LFG). This article reviews the MSW disposal practices and LFG emissions from landfills in India during the period 1994 to 2011. The worldwide trend of feasibility of LFG to energy recovery projects and recent studies in India indicate a changed perception of landfills as a source of energy. However, facilitating the implementation of LFG to energy involves a number of challenges in terms of technology, developing a standardized framework and availability of financial incentives. The legislative framework for promotion of LFG to energy projects in India has been reviewed and a comprehensive strategy and action plan for gainful LFG recovery is suggested. It is concluded that the market for LFG to energy projects is not mature in India. There are no on-ground case studies to demonstrate the feasibility of LFG to energy applications. Future research therefore should aim at LFG emission modeling studies at regional level and based on the results, pilot studies may be conducted for the potential sites in the country to establish LFG to energy recovery potential from these landfills. PMID:23255613

  7. Life-cycle-assessment of fuel-cells-based landfill-gas energy conversion technologies

    NASA Astrophysics Data System (ADS)

    Lunghi, P.; Bove, R.; Desideri, U.

    Landfill-gas (LFG) is produced as result of the biological reaction of municipal solid waste (MSW). This gas contains about 50% of methane, therefore it cannot be released into the atmosphere as it is because of its greenhouse effect consequences. The high percentage of methane encouraged researchers to find solutions to recover the related energy content for electric energy production. The most common technologies used at the present time are internal combustion reciprocating engines and gas turbines. High conversion efficiency guaranteed by fuel cells (FCs) enable to enhance the energy recovery process and to reduce emissions to air, such as NO x and CO. In any case, in order to investigate the environmental advantages associated with the electric energy generation using fuel cells, it is imperative to consider the whole "life cycle" of the system, "from cradle-to-grave". In fact, fuel cells are considered to be zero-emission devices, but, for example, emissions associated with their manufacture or for hydrogen production must be considered in order to evaluate all impacts on the environment. In the present work a molten carbonate fuel cell (MCFC) system for LFG recovery is considered and a life cycle assessment (LCA) is conducted for an evaluation of environmental consequences and to provide a guide for further environmental impact reduction.

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Laboratory and field screening strategies for measuring volatile organic compounds in landfill gas

    SciTech Connect

    Emerson, C.W.

    1999-11-01

    Distinct patterns often exist in the presence and absence of hazardous contaminants in the environment. These patterns can be used to select efficient screening tools, or groups of compounds that provide the most information on overall occurrences of a larger target group of compounds. By using these screens to indicate whether a sample is contaminated with detectable amounts of the compounds of interest, attention can be focused on those samples considered most likely to contain measurable concentrations of targeted compounds. The cost savings that result from eliminating samples that are most likely uncontaminated can be applied to obtaining additional samples that more accurately characterize the spatial or temporal variability of the environmental problem. In a retrospective application of screening techniques to the State of California's database of volatile organic compounds in landfill gas, two laboratory screening compounds, perchloroethylene and methylene chloride, represent over 95% of the total number of positive detections of a target group of 10 volatile organic compounds. Benzene and vinyl chloride, two field screening compounds that were selected using the characteristics of commercially available colorimetric detector tubes, recorded 74% of the total contaminant detections and a 52% savings in analytical costs as compared to an exhaustive analysis of every sample for all 10 volatile organic compounds. The number of detections recorded could have been improved if more sensitive and less selective field screening devices were available.

  17. 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

  18. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

    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 °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 CO2, CH4, H2, NH3, CO and NO2 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 NO2 presence in the multicomponent mixture LFG. The NO2 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 NO2 concentrations of 3.3 ppm and 330 ppb dispersed in the LFG, respectively, with a wide NO2 gas concentration range measured from 0.33 to 3.3 ppm, at the sensor temperature of 150 °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 µm 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 demonstrates high sensitivity by

  20. 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

  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. 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.

  3. 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

  4. 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

  5. Thermodynamic stability, spectroscopic identification, and gas storage capacity of CO2-CH4-N2 mixture gas hydrates: implications for landfill gas hydrates.

    PubMed

    Lee, Hyeong-Hoon; Ahn, Sook-Hyun; Nam, Byong-Uk; Kim, Byeong-Soo; Lee, Gang-Woo; Moon, Donghyun; Shin, Hyung Joon; Han, Kyu Won; Yoon, Ji-Ho

    2012-04-01

    Landfill gas (LFG), which is primarily composed of CH(4), CO(2), and N(2), is produced from the anaerobic digestion of organic materials. To investigate the feasibility of the storage and transportation of LFG via the formation of hydrate, we observed the phase equilibrium behavior of CO(2)-CH(4)-N(2) mixture hydrates. When the specific molar ratio of CO(2)/CH(4) was 40/55, the equilibrium dissociation pressures were gradually shifted to higher pressures and lower temperatures as the mole fraction of N(2) increased. X-ray diffraction revealed that the CO(2)-CH(4)-N(2) mixture hydrate prepared from the CO(2)/CH(4)/N(2) (40/55/5) gas mixture formed a structure I clathrate hydrate. A combination of Raman and solid-state (13)C NMR measurements provided detailed information regarding the cage occupancy of gas molecules trapped in the hydrate frameworks. The gas storage capacity of LFG hydrates was estimated from the experimental results for the hydrate formations under two-phase equilibrium conditions. We also confirmed that trace amounts of nonmethane organic compounds do not affect the cage occupancy of gas molecules or the thermodynamic stability of LFG hydrates. PMID:22380606

  6. 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

  7. 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.

  8. 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...

  9. Superfund Record of Decision (EPA Region 5): Land and Gas Reclamation Landfill Site, Williamstown, WI, January 1994

    SciTech Connect

    Not Available

    1994-09-01

    The document presents the decision of the Wisconsin Department of Natural Resources (WDNR) that no further source control interim action is necessary at the Land and Gas Reclamation Landfill site in the Town of Williamstown, Dodge County, Wisconsin. The WDNR has determined that no further source control interim action is necessary at this site for this first operable unit. The reason for this determination is that the source control action which was implemented under the Dodge County Circuit Court Order has eliminated potential exposure to source related contaminants, except for contaminants in the groundwater, which will be addressed in the second operable unit.

  10. 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)

  11. 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...

  12. Microbial Methane Oxidation Processes and Technologies for Mitigation of Landfill Gas Emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this paper is to review the present knowledge regarding the microbial methane oxidation in natural or engineered landfill environments with focus on process understanding, engineering experiences and modeling. This review includes seven sections. First, the methane oxidation is put in con...

  13. 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.

  14. 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...

  15. 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. PMID:21813272

  16. 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.

  17. 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.

  18. Method for designing gas tag compositions

    DOEpatents

    Gross, Kenny C.

    1995-01-01

    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 #1. Lattice locations of tag nodes in multi-dimensional space are then used in calculating the compositions of a node #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.

  19. 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.

  20. 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

  1. Evaluation of the geotechnical properties of MSW in two Brazilian landfills.

    PubMed

    Machado, Sandro Lemos; Karimpour-Fard, Mehran; Shariatmadari, Nader; Carvalho, Miriam Fatima; do Nascimento, Julio C F

    2010-12-01

    The characteristics of municipal solid waste (MSW) play a key role in many aspects of waste disposal facilities and landfills. Because most of a landfill is made up of MSW, the overall stability of the landfill slopes are governed by the strength parameters and physical properties of the MSW. These parameters are also important in interactions involving the waste body and the landfill structures: cover liner, leachate and gas collection systems. On the other hand, the composition of the waste, which affects the geotechnical behavior of the MSW, is dependent on a variety of factors such as climate, disposal technology, the culture and habits of the local community. It is therefore essential that the design and stability evaluations of landfills in each region be performed based on the local conditions and the geotechnical characteristic of the MSW. The Bandeirantes Landfill, BL, in São Paulo and the Metropolitan Center Landfill, MCL, in Salvador, are among the biggest landfills in Brazil. These two disposal facilities have been used for the development of research involving waste mechanics in recent years. Considerable work has been made in the laboratory and in the field to evaluate parameters such as water and organic contents, composition, permeability, and shear strength. This paper shows and analyzes the results of tests performed on these two landfills. The authors believe that these results could be a good reference for certain aspects and geotechnical properties of MSW materials in countries with similar conditions. PMID:20826081

  2. 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. PMID:22319493

  3. 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

  4. 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

  5. ENGINEERING BULLETIN: LANDFILL COVERS

    EPA Science Inventory

    Landfill covers are used at Superfund sites to minimize surface water infiltration and control gas migration. In many cases covers are used in conjunction with other waste treatment technologies, such as slurry walls, ground water pump-and-treat systems, and gas collection. This ...

  6. 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

  7. Environmental assessment of gas management options at the Old Ammässuo landfill (Finland) by means of LCA-modeling (EASEWASTE).

    PubMed

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

    2009-05-01

    The current landfill gas (LFG) management (based on flaring and utilization for heat generation of the collected gas) and three potential future gas management options (LFG flaring, heat generation and combined heat and power generation) for the Old Ammässuo landfill (Espoo, Finland) were evaluated by life-cycle assessment modeling. The evaluation accounts for all resource utilization and emissions to the environment related to the gas generation and management for a life-cycle time horizon of 100 yr. The assessment criteria comprise standard impact categories (global warming, photo-chemical ozone formation, stratospheric ozone depletion, acidification and nutrient enrichment) and toxicity-related impact categories (human toxicity via soil, via water and via air, eco-toxicity in soil and in water chronic). The results of the life-cycle impact assessment show that disperse emissions of LFG from the landfill surface determine the highest potential impacts in terms of global warming, stratospheric ozone depletion, and human toxicity via soil. Conversely, the impact potentials estimated for other categories are numerically-negative when the collected LFG is utilized for energy generation, demonstrating that net environmental savings can be obtained. Such savings are proportional to the amount of gas utilized for energy generation and the gas energy recovery efficiency achieved, which thus have to be regarded as key parameters. As a result, the overall best performance is found for the heat generation option - as it has the highest LFG utilization/energy recovery rates - whereas the worst performance is estimated for the LFG flaring option, as no LFG is here utilized for energy generation. Therefore, to reduce the environmental burdens caused by the current gas management strategy, more LFG should be used for energy generation. This inherently requires a superior LFG capture rate that, in addition, would reduce fugitive emissions of LFG from the landfill surface

  8. Analysis and removal of organic pollutants in biologically treated landfill leachate by an inorganic flocculent composite of Al(III)-Mg(II).

    PubMed

    Sang, Yimin; Gu, Qingbao; Sun, Tichang; Li, Fasheng; Pan, Yiting

    2008-10-01

    A novel inorganic flocculent composite of Al(III)-Mg(II) poly-magnesium-aluminum-sulfate (PMAS) is used to remove organic matter from biologically treated leachate in some landfills in Beijing, China. Jar-test experiments are employed to determine the optimum conditions for the removal of organic matter, which is represented as UV(254). Under optimum conditions, the removal of COD, BOD(5), and color is also determined. Moreover, gas chromatography coupled with mass spectrometry (GC-MS) is used to analyze the organic matter in the biologically treated leachate before and after treatment by the coagulant. The experimental results indicate that the removal of COD, BOD(5), UV(254), and color by coagulation with PMAS can reach above 65%, 60%, 85%, and 85%, respectively, under optimal conditions. This greatly weakens its pollution extent and improves its visual appeal. Forty-one kinds of organic pollutants in the biologically treated leachate were determined. Some of them belong to the Black List of water environmental preferred controlled pollutants, as judged by the United States and China. The species of alkyl, alkene, acyclic alcohol, and acyclic acyl amines are about 85% removed, some of them are removed completely, while the species of acids, esters, and ketones are removed at about 65%. Those contaminants with benzene rings, such as aromatic hydrocarbons, hydroxybenzene, aromatic alcohol, and aromatic acyl amine, are about 50% partially removed. PMID:18991941

  9. Gas plume modeling of landfill emissions - a real-life engineering application of large-eddy simulation

    NASA Astrophysics Data System (ADS)

    Zhou, B.; Chow, F. K.; Han, B.; Imhoff, P. T.

    2012-12-01

    Methane emissions from landfills pose a challenge not only for mitigation of greenhouse gases, but for regulatory monitoring efforts which seek to quantify these emissions. Current measurement practices are usually based on and limited by sparse and/or infrequent field measurements. Mesoscale atmospheric models, on the other hand, can provide better spatial and temporal coverage of the impacted region, though their usefulness is traditionally limited to regional- and synoptic-scales, due to the coarse grid-spacing as well as the treatment of turbulence. In this study, we explore the use of state-of-the-art large-eddy simulations (LES), to model CH4 emissions from Sandtown Landfill in Delaware. Since LES can explicitly resolve the unsteady, turbulent atmospheric flows, it is potentially beneficial in assessing the local impact of the CH4 plume on a short-term (hourly) scale. It can thus be used to enhance interpretation of field measurements. To ensure a faithful representation of atmospheric flow, real initial and boundary conditions are provided through grid nesting from the mesoscale to the microscale. LES is performed on the innermost domain with 30 m horizontal grid spacing. In addition, we incorporate two existing techniques, a vegetation canopy model and a tracer decay method into our LES. The former provides a better representation of the flow, and the latter is used to calculate scalar plume advection/diffusion statistics. Model results are verified against surface and airborne observations. This numerical study demonstrates the usefulness of LES in a real-life environmental engineering application. The LES results are used to help interpret tracer dilution measurements of methane emission at this site, helping to explain plume meandering and differences in tracer concentrations measured at the surface versus aloft with a weather balloon. A snapshot of the gas plume, represented by an iso-surface contour.

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

    PubMed

    Bogner, Jean E; Spokas, Kurt A; Chanton, Jeffrey P

    2011-01-01

    Compared with natural ecosystems and managed agricultural systems, engineered landfills represent a highly managed soil system for which there has been no systematic quantification of emissions from coexisting daily, intermediate, and final cover materials. We quantified the seasonal variability of CH, CO, and NO emissions from fresh refuse (no cover) and daily, intermediate, and final cover materials at northern and southern California landfill sites with engineered gas extraction systems. Fresh refuse fluxes (g m d [± SD]) averaged CH 0.053 (± 0.03), CO 135 (± 117), and NO 0.063 (± 0.059). Average CH emissions across all cover types and wet/dry seasons ranged over more than four orders of magnitude (<0.01-100 g m d) with most cover types, including both final covers, averaging <0.1 g m d with 10 to 40% of surface areas characterized by negative fluxes (uptake of atmospheric CH). The northern California intermediate cover (50 cm) had the highest CH fluxes. For both the intermediate (50-100 cm) and final (>200 cm) cover materials, below which methanogenesis was well established, the variability in gaseous fluxes was attributable to cover thickness, texture, density, and seasonally variable soil moisture and temperature at suboptimal conditions for CH oxidation. Thin daily covers (30 cm local soil) and fresh refuse generally had the highest CO and NO fluxes, indicating rapid onset of aerobic and semi-aerobic processes in recently buried refuse, with rates similar to soil ecosystems and windrow composting of organic waste. This study has emphasized the need for more systematic field quantification of seasonal emissions from multiple types of engineered covers. PMID:21546687

  11. 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 ...

  12. 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...

  13. Gas turbine engine and composite parts

    SciTech Connect

    Prewo, K.M.; Brennan, J.J.

    1988-04-19

    A gas turbine engine core engine component blade, vane, disk, side plate, seal, combustor liner, flap, burner case structure, or turbine case structure, is described comprising a silicon carbide fiber reinforced glass composite consisting essentially of about 30% to about 70% by volume silicon carbide fibers in a glass matrix selected from the group consisting of borosilicate glass, high silica content glass, aluminosilicate glass and mixtures thereof, the composite having a fracture toughness exemplified by a critical stress intensity factor above about 15,000 psi (inch)/sup 1/2/, high temperature strength, high temperature oxidation stability and insulating properties.

  14. 40 CFR Table Hh-3 to Subpart Hh of... - Landfill Gas Collection Efficiencies

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...: Area with daily soil cover and active gas collection CE3: 60%. A4: Area with an intermediate soil cover, or a final soil cover not meeting the criteria for A5 below, and active gas collection CE4: 75%. A5: Area with a final soil cover of 3 feet or thicker of clay and/or geomembrane cover system and...

  15. 40 CFR Table Hh-3 to Subpart Hh of... - Landfill Gas Collection Efficiencies

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...: Area with daily soil cover and active gas collection CE3: 60%. A4: Area with an intermediate soil cover, or a final soil cover not meeting the criteria for A5 below, and active gas collection CE4: 75%. A5: Area with a final soil cover of 3 feet or thicker of clay and/or geomembrane cover system and...

  16. 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

  17. 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

  18. 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

  19. 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.

  20. Controls on coal-bed gas composition

    SciTech Connect

    Rice, D. )

    1993-09-01

    Coal-bed gases are quite variable in composition. In addition to methane, they can contain significant amounts of heavier hydrocarbon gases (C2+>20%) and carbon dioxide (>99%). Coal-bed gases are also variable in their isotopic composition: [delta][sup 13]C[sub 1]:-70.4 to - 16.8 ppt, [delta][sup 13]C[sub 2]:-29.2 to -22.8 ppt, [delta]D[sub 1]:-333 to -117 ppt, and [delta]C[sub CO2]:26.6 to +18.6 ppt. the primary controls of hydrocarbon gas composition are coal rank and composition and depth/temperature. Biogenic gas is generated by the degradation of organic matter at shallow depths and low temperatures in coals of any rank and is mainly methane. Thermogenic coal-bed gas results from devolatilization of coal at ranks of high- volatile bituminous and higher. These gases can be wet at intermediate ranks (high- to medium-volatile bituminous) and are dry at higher ranks. [delta][sup 13]C and [delta]D values become more positive with increasing rank. In addition, at intermediate ranks, hydrogen-rich coals generate wetter gases than do oxygen-rich coals. Shallow coal-bed gas is relatively dry with isotopically light methane as compared to gas from deeper coal, regardless of rank. This trend results from the original gases being altered by relatively recent bacterial activity (aerobic oxidation of heavier hydrocarbons and/or anaerobic generation of biogenic methane). This alteration occurs at depths <3,000 ft and is controlled by the physical characteristics of the coal beds, burial history, and groundwater flow. Carbon dioxide generated during devolatilization commonly is not preserved in present-day coal-bed gases because it is highly reactive and soluble in water. Significant present-day amounts of carbon dioxide can be the result of several processes not related to coalification, such as recent bacterial activity, thermal destruction of carbonates, and migration from magma chambers or the upper mantle.

  1. 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

  2. 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

  3. 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.

  4. 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

  5. Acoustic composition sensor for cryogenic gas mixtures

    NASA Technical Reports Server (NTRS)

    Shakkottai, P.; Kwack, E. Y.; Luchik, T. S.; Back, L. H.

    1991-01-01

    An acoustic sensor useful for the determination of the composition of a gaseous binary mixture in cryogenic liquid spills has been characterized. One version of the instrument traps a known mixture of helium and nitrogen at ambient temperature in a tube which is interrogated by sonic pulses to determine the speed of sound and hence the composition. Experimental data shows that this sensor is quite accurate. The second version uses two unconfined microphones which sense sound pulses. Experimental data acquired during mixing when liquid nitrogen is poured into a vessel of gaseous helium is presented. Data during transient cooling of the tubular sensor containing nitrogen when the sensor is dipped into liquid nitrogen and during transient warm-up when the sensor is withdrawn are also presented. This sensor is being developed for use in the mixing of liquid cryogens with gas evolution in the simulation of liquid hydrogen/liquid oxygen explosion hazards.

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

    NASA Technical Reports Server (NTRS)

    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.

  7. 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

  8. Tunable composite membranes for gas separations

    SciTech Connect

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

    1999-05-01

    The use of membrane technology for gas separations offers significant thermodynamic and economic advantages over distillation processes. Target separations of importance to the coal and energy fields include N{sub 2}/O{sub 2}, H{sub 2}S/syngas and CO{sub 2}/CH{sub 4}. Current strategies for improving these separations are largely directed towards processable polymers with thin (< 500 {angstrom}) skins. Unfortunately most polymeric materials that provide commercially viable permeation rates exhibit poor selectivities and vice versa and there are inherent limitations in gas permeability/permselectivity for pure polymers. The strategy relies on modification of composite membranes, preferably in situ, to enhance the permselectivity while maintaining acceptable permeabilities. The composites consist of electroactive polymers (which can be switched from rubbery to glassy), filled with selective absorbents (zeolites) which are impregnated with metals or catalysts to effect facilitated transport. The project is multifaceted and involves the efforts of a polymer synthesis group, a microporous materials group, a microscopy group and a permeability measurements group, all working in concert. This final report summarizes the results of the efforts on the project.

  9. 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. PMID:25323145

  10. 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.

  11. 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

  12. 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

  13. 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...

  14. Method and composition for generating nitrogen gas

    SciTech Connect

    Pietz, J.F.

    1988-01-26

    A solid composition is described for generating nitrogen gas substantially free of noxious and toxic impurities for inflating an air cushion in a vehicle passenger restraint system and capable of substantially fully inflating such cushion in the elapsed time between the occurrence of a primary collision of the vehicle with another object and secondary collisions occurring as a result thereof; comprising a mixture of alkali metal azide and at least a stoichiometric amount of a metal oxide selected from the group consisting of iron, titanium and copper oxides and mixtures thereof. The metal oxide is capable of reacting exothermically with the alkaki metal azide and wherein the metal of the oxide is lower in the electromotive series than the alkali metal of the azide and is a metal other than (the) an alkali metal.

  15. 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.

  16. Composite body for gas discharge lamp

    SciTech Connect

    Driessen, A. J. G. C.; Geertsema, E. B.; Oomen, J. J. C.; Rouwendal, J. W.

    1985-02-26

    Composite body, a gas discharge lamp having a sodium pressure from 300-600 torr in particular, having an envelope of densely sintered aluminium oxide or of other sodium vapor-resistant materials and a feed-through member of tantalum, niobium or other metals equivalent thereto, The bonding material consisting of a finely dispersed polycrystalline product having a composition in mole % between the following limits: Al/sub 2/O/sub 3/-5-70 at least one oxide chosen from Sc/sub 2/O/sub 3/ and Ti/sub 2/O /SUB x/ , wherein 2

  17. Methane emissions from MBT landfills.

    PubMed

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

    2013-09-01

    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(3)CH(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(4)/(m(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) model of the IPCC Guidelines for National Greenhouse Gas Inventories, 2006, was used to estimate the methane emissions from MBT landfills. Due to the calculation made by the authors emissions in the range of 60,000-135,000 t CO(2-eq.)/a for all German MBT landfills can be expected. This wide range shows the uncertainties when the here used procedure and the limited available data are applied

  18. 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 ...

  19. 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

  20. 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...

  1. 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 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...

  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 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...

  3. 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 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...

  4. 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...

  5. TUNABLE COMPOSITE MEMBRANES FOR GAS SEPARATIONS

    SciTech Connect

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

    1998-07-01

    Smooth, dense, uniformly thick membranes were solution cast from poly(3-octylthiophene) (POT) and their permeability properties were investigated for N{sub 2}, O{sub 2}, CH{sub 4}, and CO{sub 2} (P{sub N{sub 2}} = 5.8 {+-} 0.4, P{sub O{sub 2}} = 15.6 {+-} 0.8, P{sub CH{sub 4}} = 17.8 {+-} 1.4, P{sub CO{sub 2}} = 63.6 {+-} 2.2 Barrers), and selectivity properties were calculated ({alpha}{sub O{sub 2}/N{sub 2}} = 2.7 {+-} 0.2, {alpha}{sub CO{sub 2}/N{sub 2}} = 11.2 {+-} 0.8, {alpha}{sub CO{sub 2}/CH{sub 4}} = 3.6 {+-} 0.2). NaY/POT composite membranes (20, 30, and 40% w/w zeolite) were prepared by stirring the polymer into a zeolitic suspension. Facilitated transport of gases (N{sub 2}, O{sub 2}, CH{sub 4}, and CO{sub 2}) was observed for each of the zeolite loadings, the magnitude of which depended on the chemical nature of the gas and polymer/zeolite-penetrant interaction. Maximum facilitation was observed for 40% NaY/POT composite membranes (Facilitation ratio of N{sub 2} = 0.38 {+-} 0.03, O{sub 2} = 0.56 {+-} 0.02, CH{sub 4} = 0.13 {+-} 0.01, CO{sub 2} = 0.71 {+-} 0.02). An increase in the selectivity of gases was also observed for all zeolite loadings.

  6. 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).

  7. 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.

  8. 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

  9. 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.

  10. Metal oxides remove hydrogen sulfide from landfill gas produced from waste mixed with plaster board under wet conditions.

    PubMed

    Bergersen, Ove; Haarstad, Ketil

    2008-08-01

    Hydrogen sulfide (H2S) is a major odorant in landfills. We have studied H2S production from landfill residual waste with and without sulfur-containing plaster board, including the influence of the water content in the waste. The laboratory experiments were conducted in 30-L polyethylene containers with a controlled water level. We also studied how different materials removed H2S in reactive layers on top of the waste. The organic waste produced H2S in concentrations of up to 40 parts per million (ppm) over a period of 80 days. When plaster board was added, the H2S concentration increased to 800 ppm after a lag period of approximately 40 days with a high water level, and to approximately 100 ppm after 50 days with a low water level. The methane (CH4) concentration in the initial experiment was between 5 and 70% after 80 days. The CH4 concentration in the second experiment increased to nearly 70% in the container with a high water level, slowly declining to approximately 60% between days 20 and 60. The CH4 concentrations during the experiments resembled normal landfill concentrations. Metallic filter materials were very efficient in removing H2S, whereas organic filter materials showed poor H2S removal. PMID:18720651

  11. ESTIMATE OF METHANE EMISSIONS FROM U.S. LANDFILLS

    EPA Science Inventory

    The report describes the development of a statistical regression model used for estimating methane (CH4) emissions, which relates landfill gas (LFG) flow rates to waste-in-place data from 105 landfills with LFG recovery projects. (NOTE: CH4 flow rates from landfills with LFG reco...

  12. 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

  13. 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.

  14. 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.

  15. MANAGEMENT OF GAS AND LEACHATE IN LANDFILLS: PROCEEDINGS OF THE ANNUAL MUNICIPAL SOLID WASTE RESEARCH SYMPOSIUM (3RD) HELD AT ST. LOUIS, MISSOURI ON MARCH 14, 15 AND 16, 1977

    EPA Science Inventory

    Contents: Current research on land disposal of municipal solid wastes; Summary of office of solid waste gas and leachate activities; State of Missouri solid waste management activities; Region VII solid waste activities; Landfill research activities in Canada; The effects of indu...

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  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. 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.

  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. Composition of Low-redshift Halo Gas

    NASA Astrophysics Data System (ADS)

    Cen, Renyue

    2013-06-01

    Halo gas in low-z (z < 0.5) >=0.1 L * galaxies in high-resolution, large-scale cosmological hydrodynamic simulations is examined with respect to three components: cold, warm, and hot with temperatures of <105, 105-6, and >106 K, respectively. Utilizing O VI λλ1032, 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 ~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.

  5. 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.

  6. 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.

  7. Modelling of biogas extraction at an Italian landfill accepting mechanically and biologically treated municipal solid waste.

    PubMed

    Calabrò, Paolo S; Orsi, Sirio; Gentili, Emiliano; Carlo, Meoni

    2011-12-01

    This paper presents the results of the modelling of the biogas extraction in a full-scale Italian landfill by the USEPA LandGEM model and the Andreottola-Cossu approach. The landfill chosen for this research ('Il Fossetto' plant, Monsummano Terme, Italy) had accepted mixed municipal raw waste for about 15 years. In the year 2003 a mechanical biological treatment (MBT) was implemented and starting from the end of the year 2006, the recirculation in the landfill of the concentrated leachate coming from the internal membrane leachate treatment plant was put into practice. The USEPA LandGEM model and the Andreottola-Cossu approach were chosen since they require only input data routinely acquired during landfill management (waste amount and composition) and allow a simplified calibration, therefore they are potentially useful for practical purposes such as landfill gas management. The results given by the models are compared with measured data and analysed in order to verify the impact of MBT on biogas production; moreover, the possible effects of the recirculation of the concentrated leachate are discussed. The results clearly show how both models can adequately fit measured data even after MBT implementation. Model performance was significantly reduced for the period after the beginning of recirculation of concentrated leachate when the probable inhibition of methane production, due to the competition between methanogens and sulfate-reducing bacteria, significantly influenced the biogas production and composition. PMID:21930528

  8. 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.

  9. Ground penetrating radar characterization of a landfill

    NASA Astrophysics Data System (ADS)

    Yochim, April Theresa

    Ground penetrating radar was investigated in an active landfill to determine if the in-situ water content could be measured. Water content is an important parameter in predicting the generation of landfill gas (LFG), an important renewable energy source. Unfortunately, predicting the quantity of LFG is difficult due to the heterogeneities present in a landfill and the lack of in-situ input parameters. GPR is a non-invasive, near-surface geophysical technique that provides high resolution images of dielectric properties in the earth's subsurface. A transmitter emits high frequency (10 - 1000 MHz) electromagnetic pulses through the subsurface, with the receiver recording the echo. Specialized software is then used to create images of the subsurface. The challenge with using GPR in landfills is the heterogeneity of the subsurface and the clay cap linear covering landfills, both affecting the transmission of the electromagnetic pulses. The use of GPR in a landfill was evaluated at the Region of Waterloo's Waste Management Centre. Measurements were completed using both the surface and the borehole approach. The results indicated that a borehole GPR can be used, with successful measurement of water content a function of borehole separation distance and frequency of the electromagnetic pulses. The developed approach was confirmed at the City of Hamilton's Glanbrook Landfill. The successful comparison of in-situ water content values to laboratory determined values at both landfills shows that GPR can be used to measure in-situ water content.

  10. 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. PMID:25970820

  11. 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.

  12. 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. PMID:26525969

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. TUNABLE COMPOSITE MEMBRANES FOR GAS SEPARATIONS

    SciTech Connect

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

    1999-01-01

    Poly 2-(3-thienyl)ethylacetate (PAET) was synthesized and solution cast as thin films to form dense membranes. These membranes are mechanically robust and are redox active, holding out promise as gas separation materials. The permeability properties of PAET membranes were evaluated for N{sub 2} (0.048 {+-} 0.008 Barrers), O{sub 2} (0.24 {+-} 0.02 Barrers), CH{sub 4} (0.081 {+-} 0.005 Barrers), and CO{sub 2} (1.4 {+-} 0.1 Barrers). The corresponding selectivity values ({alpha}) were: O{sub 2}/N{sub 2} = 5.1, CO{sub 2}/N{sub 2} = 29, and CO{sub 2}/CH{sub 4} = 18.

  18. 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)

  19. 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.

  20. Fuel composition effects on natural gas vehicle emissions

    SciTech Connect

    Blazek, C.F.; Grimes, J.; Freeman, P.; Bailey, B.K.; Colucci, C.

    1994-09-01

    Under a contract from DOE`s National Renewable Energy Laboratory (NREL) and support from Brooklyn Union Gas Company (BUG), Northern Illinois Gas Co., the Institute of Gas Technology (IGT) evaluated four state-of-the-art, electronic, closed-loop natural gas vehicle (NGV) conversion systems. The systems included an Impco electronic closed-loop system, Mogas electronic closed-loop system, Stewart and Stevenson`s GFI system, and an Automotive Natural Gas Inc. (ANGI) Level 1 electronic closed-loop conversion system. Conversion system evaluation included emission testing per 40 CFR Part 86, and driveability. All testing was performed with a 1993 Chevy Lumina equipped with a 3.1 liter MPFI V6 engine. Each system was emission tested using three different certified compositions of natural gas, representing the 10th, mean and 90th percentile gas compositions distributed in the United States. Emission testing on indolene was performed prior to conversion kit testing to establish a base emission value. Indolene testing was also performed at the end of the project when the vehicle was converted to its OEM configuration to ensure that the vehicle`s emissions were not altered during testing. The results of these tests will be presented.

  1. 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.

  2. 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.

  3. 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.

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

    PubMed

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

    2007-01-01

    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. PMID:17382531

  5. 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.

  6. 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.

  7. 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.

  8. Composite clay materials for removal of SOx from gas streams

    SciTech Connect

    Pinnavaia, T.J.; Polansky, C.A.; Amarasekera, J.

    1993-07-06

    A method is described for preparing a composite material capable of removing SO[sub x] from a gas stream comprising the steps of: (a) providing a suspension containing a smectite clay in water; (b) dissolving an amount of sodium carbonate in the suspension of the clay; (c) adding a soluble alkaline earth metal salt in stoichiometric amount for reaction with the sodium carbonate to form an alkaline earth metal carbonate precipitate in the suspension with the clay; and (d) drying the suspension to provide the composite material, wherein when the composite material is heated, the SO[sub x], is removed from the gas. A method is described in accordance with claim 3 wherein the alkaline earth metal carbonate and clay are mixed with an iron salt selected from the group consisting of ferric chloride and ferric nitrate. A method is described in accordance with claim 3 wherein the alkaline earth metal is selected from the group consisting of magnesium and calcium.

  9. 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.

  10. Simulations of Flow, Transport, and Biodegradation in Landfills

    NASA Astrophysics Data System (ADS)

    Oldenburg, C. M.; Borglin, S. E.; Hazen, T. C.

    2002-12-01

    Biotreatment of landfill materials may involve coupled nonisothermal flow and transport of water and gas in the refuse mass. With the objective of carrying out analyses that depend on flow and transport processes, we are developing T2LBM, a module for the TOUGH2 multiphase flow and transport simulator that implements a Landfill Bioreactor Model. T2LBM models the processes of aerobic and anaerobic biodegradation of municipal solid waste and the associated three-dimensional flow and transport of gas, liquid, and heat through the refuse mass. The components modeled in T2LBM are water, acetic acid, carbon dioxide, methane, oxygen, and nitrogen in aqueous and gas phases, with partitioning specified by temperature-dependent Henry's coefficients. The local oxygen concentration is used to control whether aerobic or anaerobic biodegradation reactions occur to produce carbon dioxide, or methane and carbon dioxide, respectively. Acetic acid is used as a proxy for all of the biodegradable components in the refuse. The biodegradation rate of acetic acid is modeled using a Monod kinetic rate law for the exothermic reactions in the aqueous phase. The compaction rate is specified by the user and modeled as a linear decrease with time of porosity and contraction of the vertical grid dimension by generation of a new grid at each time step. Local differences in moisture content, pressure, gas composition, aerobicity, and temperature, among other properties, within the heterogeneous refuse can be modeled with T2LBM. Comparison of simulation results against observations of an aerobic landfill bioreactor laboratory experiment and an anaerobic field pilot study show good agreement for oxygen consumption and gas production. Predictions and sensitivity analyses of different biotreatments can be made using this new simulation capability. This work was supported by Laboratory Directed Research and Development Funds at Lawrence Berkeley National Laboratory under Department of Energy Contract

  11. 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

  12. The Gas Leakage Analysis in C/C Composites

    NASA Astrophysics Data System (ADS)

    Nishiyama, Yuichi; Hatta, Hiroshi; Bando, Takamasa; Sugibayashi, Toshio

    Gas leakage through carbon fiber reinforcement carbon composites, C/Cs, was discussed so as to apply C/Cs to heat exchangers in an engine system for a future space-plane. Since C/Cs include many cracks and pores, gas easily leaks through C/Cs. To predict and to prevent the gas flow through a C/C, leakage rate was measured as a function of pressure and gas flow path was identified by micro-observation of the C/C. Then, several analytical models were examined to clarify principal mechanism yielding gas flow resistance. It was found that laminar flow models gave far small flow resistance compared with experimental results, but a model based on adiabatic expansion and compression flow, used for gas leak through labyrinth seals, resulted in reasonable agreement. Finally, Si impregnation in a C/C was examined to minimize the gas leakage. This treatment was shown to be an excellent measure to reduce the gas leakage through C/C.

  13. 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

  14. Hazardous pollutants in class II landfills

    SciTech Connect

    Wood, J.A.; Porter, M.L.

    1987-05-01

    Class II landfills accept nontoxic municipal trash. Their gaseous emissions were originally assumed to be relatively free of hazardous substances. However, one Class II site in Southern California was found to be emitting enough vinyl chloride to exceed the California Air Quality Standard of 10 ppb for a 24-hour average in surrounding neighborhood. This paper presents a summary of the results of the analysis of landfill gas from over 20 additional Class II landfills. Ambient air surveys were conducted around five of the landfills. About 90% of the landfills contained measurable amounts of vinyl chloride and/or benzene. The concentrations exceeded 1 ppm in about half of the sites studied. Vinyl chloride is produced in situ by the action of bacteria on chlorinated solvents, and can be found in landfills that have been closed for over 30 years. The relative amounts of methane and vinyl chloride vary so much within a single landfill that methane measurements cannot be used as a surrogate for vinyl chloride.

  15. 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

  16. 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

  17. 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. PMID:19423588

  18. 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

  19. Field testing the Raman gas composition sensor for gas turbine operation

    SciTech Connect

    Buric, M.; Chorpening, B.; Mullem, J.; Ranalli, J.; Woodruff, S.

    2012-01-01

    A gas composition sensor based on Raman spectroscopy using reflective metal lined capillary waveguides is tested under field conditions for feed-forward applications in gas turbine control. The capillary waveguide enables effective use of low powered lasers and rapid composition determination, for computation of required parameters to pre-adjust burner control based on incoming fuel. Tests on high pressure fuel streams show sub-second time response and better than one percent accuracy on natural gas fuel mixtures. Fuel composition and Wobbe constant values are provided at one second intervals or faster. The sensor, designed and constructed at NETL, is packaged for Class I Division 2 operations typical of gas turbine environments, and samples gas at up to 800 psig. Simultaneous determination of the hydrocarbons methane, ethane, and propane plus CO, CO2, H2O, H2, N2, and O2 are realized. The capillary waveguide permits use of miniature spectrometers and laser power of less than 100 mW. The capillary dimensions of 1 m length and 300 μm ID also enable a full sample exchange in 0.4 s or less at 5 psig pressure differential, which allows a fast response to changes in sample composition. Sensor operation under field operation conditions will be reported.

  20. Nanostructured Tungsten Oxide Composite for High-Performance Gas Sensors.

    PubMed

    Chen, Siyuan Feng; Aldalbahi, Ali; Feng, Peter Xianping

    2015-01-01

    We report the results of composite tungsten oxide nanowires-based gas sensors. The morphologic surface, crystallographic structures, and chemical compositions of the obtained nanowires have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman scattering, respectively. The experimental measurements reveal that each wire consists of crystalline nanoparticles with an average diameter of less than 250 nm. By using the synthesized nanowires, highly sensitive prototypic gas sensors have been designed and fabricated. The dependence of the sensitivity of tungsten oxide nanowires to the methane and hydrogen gases as a function of time has been obtained. Various sensing parameters such as sensitivity, response time, stability, and repeatability were investigated in order to reveal the sensing ability. PMID:26512670

  1. Nanostructured Tungsten Oxide Composite for High-Performance Gas Sensors

    PubMed Central

    Feng-Chen, Siyuan; Aldalbahi, Ali; Feng, Peter Xianping

    2015-01-01

    We report the results of composite tungsten oxide nanowires-based gas sensors. The morphologic surface, crystallographic structures, and chemical compositions of the obtained nanowires have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman scattering, respectively. The experimental measurements reveal that each wire consists of crystalline nanoparticles with an average diameter of less than 250 nm. By using the synthesized nanowires, highly sensitive prototypic gas sensors have been designed and fabricated. The dependence of the sensitivity of tungsten oxide nanowires to the methane and hydrogen gases as a function of time has been obtained. Various sensing parameters such as sensitivity, response time, stability, and repeatability were investigated in order to reveal the sensing ability. PMID:26512670

  2. 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.

  3. 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.

  4. Critical evaluation of factors required to terminate the postclosure monitoring period at solid waste landfills.

    PubMed

    Barlaz, Morton A; Rooker, Alix P; Kjeldsen, Peter; Gabr, Mohammed A; Bordent, Robert C

    2002-08-15

    Regulations governing the disposal of solid waste in landfills specify that they must be monitored for 30 years after closure unless this period is extended by the governing regulatory authority. Given the wide range of conditions under which refuse is buried, technical criteria, rather than a specific time period, are preferable for evaluation of when it is acceptable to terminate postclosure monitoring. The objectives of this paper are to identify and evaluate parameters that can be used to define the end of the postclosure monitoring period and to present a conceptual framework for an investigation of whether postclosure monitoring can be terminated at a landfill. Parameters evaluated include leachate composition and leachate and gas production. Estimates of leachate production from closed landfills are used to assess the potential environmental impacts of a hypothetical release to surface water or groundwater. The acceptability of gaseous releases should be evaluated against criteria for odors, the potential for subsurface migration, and greenhouse gas and ozone precursor emissions. The approach presented here must be tested on a site-specific basis to identify additional data requirements and regulatory activity that might be required to prepare regulators for the large number of requests to terminate postclosure monitoring expected over the next 20 years. An approach in which the frequency and extent of postclosure monitoring is reduced as warranted by site-specific data and impact analysis should provide an effective strategy to manage closed landfills. PMID:12214635

  5. 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.

  6. 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.

  7. 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.

  8. 30 CFR 36.43 - Determination of exhaust-gas composition.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Determination of exhaust-gas composition. 36.43... TRANSPORTATION EQUIPMENT Test Requirements § 36.43 Determination of exhaust-gas composition. (a) Samples shall be taken to determine the composition of the exhaust gas while the engine is operated at loads and...

  9. 30 CFR 36.43 - Determination of exhaust-gas composition.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Determination of exhaust-gas composition. 36.43... TRANSPORTATION EQUIPMENT Test Requirements § 36.43 Determination of exhaust-gas composition. (a) Samples shall be taken to determine the composition of the exhaust gas while the engine is operated at loads and...

  10. 30 CFR 36.43 - Determination of exhaust-gas composition.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Determination of exhaust-gas composition. 36.43... TRANSPORTATION EQUIPMENT Test Requirements § 36.43 Determination of exhaust-gas composition. (a) Samples shall be taken to determine the composition of the exhaust gas while the engine is operated at loads and...

  11. 30 CFR 36.43 - Determination of exhaust-gas composition.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Determination of exhaust-gas composition. 36.43... TRANSPORTATION EQUIPMENT Test Requirements § 36.43 Determination of exhaust-gas composition. (a) Samples shall be taken to determine the composition of the exhaust gas while the engine is operated at loads and...

  12. 30 CFR 36.43 - Determination of exhaust-gas composition.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Determination of exhaust-gas composition. 36.43... TRANSPORTATION EQUIPMENT Test Requirements § 36.43 Determination of exhaust-gas composition. (a) Samples shall be taken to determine the composition of the exhaust gas while the engine is operated at loads and...

  13. 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.

  14. 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

  15. 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

  16. 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...

  17. AP-42 ADDITIONS AND REVISIONS - LANDFILLS (COMBUSTION CONTROLS)

    EPA Science Inventory

    This project develops emission factors, etc., for landfills, in particular for combustion devices fed by landfill gas, for incorporation into AP-42. AP-42 is a massive collection of information concerning processes which generate air emissions and presents emission factors and co...

  18. DEVELOPMENT OF AN EMPIRICAL MODEL OF METHANE EMISSIONS FROM LANDFILLS

    EPA Science Inventory

    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 (...

  19. 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.

  20. 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

  1. Landfill disposal systems.

    PubMed

    Slimak, K M

    1978-12-01

    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

  2. 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.

  3. 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.

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

    PubMed

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

    2011-11-01

    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 m3) with different composite liners (R1: 0.10+0.10 m of compacted clay liner (CCL), L(e) = 0.20 m, k(e) = 1 × 10(-8) m/s, R2: 0.002-m-thick damaged high-density polyethylene (HDPE) geomembrane overlying 0.10+0.10 m of CCL, L(e) = 0.20 m, k(e) = 1 × 10(-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(e) = 0.22 m, k(e) = 1 × 10(-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(e) = 0.22 m, k(e) = 4.24 × 10(-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 4.77×10(-10) to 10.67 × 10(-10)m2/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, dispersion coefficients of Cu, ranging from 3.47 × 10(-6) m(2)/s to 5.37 × 10(-2) m2/s, was determined to be higher than others obtained for Zn and Fe. Average molecular diffusion coefficients of phenolic compounds were estimated to be about 5.64 × 10(-10) m2/s, 5.37 × 10(-10) m2/s, 2.69 × 10(-10) m2/s and 3.29 × 10(-10) m2/s for R1, R2, R3 and R4 systems, respectively. The findings of this study clearly indicated that about 35-50% of transport of phenolic compounds to the groundwater

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. Noble Gas Compositions in Muong Nong-type Tektites

    NASA Astrophysics Data System (ADS)

    Matsubara, K.; Matsuda, J.; Koeberl, C.

    1993-07-01

    Tektites are natural silica-rich glasses and are thought to be produced during meteorite collisions with the Earth, similar to impact glasses. They occur in four geographically restricted areas and can be divided in three subgroups: normal or splash-form tektites, aerodynamically shaped tektites, and Muong Nong-type tektites [1]. Splash-form and aerodynamically shaped tektites are several grams in weight and are generally homogeneous in chemistry. On the other hand, Muong Nong-type tektites are up to several kilograms in weight, are irregular in shape, and show layered structure. They are inhomogeneous in chemistry and are enriched in volatile elements such as halogens, boron, zinc, etc., compared to splash-form tektites [1]. Muong Nong-type tektites have larger vesicles than splash-form and aerodynamically shaped tektites. This shows that Muong Nong-type tektites are different from splash-form and aerodynamically shaped tektites in several aspects. We measured noble gas compositions in splash-form tektites [2] and impact glasses [3,4]. Although Ne concentrations in tektites and impact glasses were similar to each other, heavy noble gas (Ar, Kr, and Xe) concentrations in tektites were about 2 orders of magnitude lower than those in impact glasses. In this study, we studied noble gas compositions in some Muong Nong-type tektites in order to compare them with splash-form tektites. Muong Nong-type tektite samples used in this study originated from Ubon Ratchatani in East Thailand, near the border of Laos. Geochemical studies of the samples were made by Koeberl [5]. We measured noble gas concentrations and Ne and Ar isotopic compositions in four Muong Nong-type tektites using mass spectrometry. Noble gases were extracted by three methods: laser probe, crushing, and stepwise heating. Chipped samples of two Muong Nong-type tektites were used in laser probe analysis. We used 160-380 mg of samples for noble gas analysis by crushing and stepwise-heating methods. Noble gas

  10. Ceramic Composite Development for Gas Turbine Engine Hot Section Components

    NASA Technical Reports Server (NTRS)

    DiCarlo, James A.; VANrOODE, mARK

    2006-01-01

    The development of ceramic materials for incorporation into the hot section of gas turbine engines has been ongoing for about fifty years. Researchers have designed, developed, and tested ceramic gas turbine components in rigs and engines for automotive, aero-propulsion, industrial, and utility power applications. Today, primarily because of materials limitations and/or economic factors, major challenges still remain for the implementation of ceramic components in gas turbines. For example, because of low fracture toughness, monolithic ceramics continue to suffer from the risk of failure due to unknown extrinsic damage events during engine service. On the other hand, ceramic matrix composites (CMC) with their ability to display much higher damage tolerance appear to be the materials of choice for current and future engine components. The objective of this paper is to briefly review the design and property status of CMC materials for implementation within the combustor and turbine sections for gas turbine engine applications. It is shown that although CMC systems have advanced significantly in thermo-structural performance within recent years, certain challenges still exist in terms of producibility, design, and affordability for commercial CMC turbine components. Nevertheless, there exist some recent successful efforts for prototype CMC components within different engine types.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. Bioreactor landfill technology in municipal solid waste treatment: an overview.

    PubMed

    Kumar, Sunil; Chiemchaisri, Chart; Mudhoo, Ackmez

    2011-03-01

    In recent years, due to an advance in knowledge of landfill behaviour and decomposition processes of municipal solid waste, there has been a strong thrust to upgrade existing landfill technologies for optimizing these degradation processes and thereafter harness a maximum of the useful bioavailable matter in the form of higher landfill gas generation rates. Operating landfills as bioreactors for enhancing the stabilization of wastes is one such technology option that has been recently investigated and has already been in use in many countries. A few full-scale implementations of this novel technology are gaining momentum in landfill research and development activities. The publication of bioreactor landfill research has resulted in a wide pool of knowledge and useful engineering data. This review covers leachate recirculation and stabilization, nitrogen transformation and corresponding extensive laboratory- and pilot-scale research, the bioreactor landfill concept, the benefits to be derived from this bioreactor landfill technology, and the design and operational issues and research trends that form the basis of applied landfill research. PMID:20578971

  17. Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials.

    PubMed

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

    2011-05-01

    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(-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 100g CH(4)m(-2)d(-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(4)m(-2)d(-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 and diffusive ingress of

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 3-D woven ceramic composite hot gas filter development

    SciTech Connect

    Lane, Jay E.; LeCostaouec, Jean-Francois; LeCostaouec, J.F., Westinghouse

    1998-01-01

    Westinghouse, with Techniweave as a major subcontractor, is conducting a three-phase program aimed at providing advanced candle filters for a 1997 pilot-scale demonstration in one of the two hot- gas filter systems at Southern Company Service`s Wilsonville PSD Facility. The Base Program (Phases I and 11) goal is to develop and demonstrate the suitability of the Westinghouse/ Techniweave next- generation, composite, candle filter for use in Pressurized Fluidized- Bed Combustion (PFBC) and/or Integrated Gasification Combined-Cycle (IGCC) power generation systems. The Optional Task (Phase 111, Task 5) objective is to fabricate, inspect, and ship to Wilsonville 50 advanced candle filters for pilot-scale testing.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. ADAPTING WOODY SPECIES AND PLANTING TECHNIQUES TO LANDFILL CONDITIONS, FIELD AND LABORATORY INVESTIGATIONS

    EPA Science Inventory

    A study was undertaken to determine which tree species can best maintain themselves in a landfill environment; to investigate the feasibility of preventing landfill gas from penetrating the root zone of selected species by using gas-barrier techniques; and to identify the (those)...

  14. 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...

  15. Cement compositions for cementing wells allowing pressure gas channeling in the cemented annulus to be controlled

    SciTech Connect

    Porcevaux, P. A.; Piot, B. M.; Vercaemer, C. J.

    1985-08-27

    The invention relates to cement compositions for cementing wells, which allow pressure gas-channeling to be effectively controlled up to more than about 485 F. The cement composition contains a styrene-butadiene latex and a stabilizer. The film of latex interrupts gas-channeling after an extremely brief path.

  16. 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.

  17. Performance of bioreactor landfill with waste mined from a dumpsite.

    PubMed

    Karthikeyan, Obuli P; Swati, M; Nagendran, R; Joseph, Kurian

    2007-12-01

    Emissions from landfills via leachate and gas are influenced by state and stability of the organic matter in the solid waste and the environmental conditions within the landfill. This paper describes a modified, ecologically sound waste treatment technique, where municipal solid waste is anaerobically treated in a lysimeter-scale landfill bioreactor with leachate recirculation to enhance organic degradation. The results demonstrate a substantial decrease in organic matter (BOD 99%, COD 88% and TOC 81%) and a clear decrease in nutrient concentrations especially ammonia (85%) over a period of 1 year with leachate recirculation. PMID:17457683

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Process for dissolving coke oven deposits comprising atomizing a composition containing N-methyl-2-pyrrolidone into the gas lines

    SciTech Connect

    Stafford, M.L.; Nicholson, G.M.

    1993-07-06

    A method is described for cleaning gas lines in coke oven batteries comprising atomizing a composition into the gas lines of coke oven batteries, where the composition comprises N-methyl-2-pyrrolidone.

  7. 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

  8. Measuring Gas Composition and Pressure Within Sealed Containers Using Acoustic Resonance Spectroscopy

    SciTech Connect

    Veirs, D.K.; Heiple, C.R.; Rosenblatt, G.M.; Baiardo, J.P.

    1997-05-19

    Interim and long-term storage of carefully prepared plutonium material within hermetically sealed containers may generate dangerous gas pressures and compositions. The authors have been investigating the application of acoustic resonance spectroscopy to non-intrusively monitor changes in these parameters within sealed containers. In this approach a drum-like gas cavity is formed within the storage container which is excited using a piezoelectric transducer mounted on the outside of the container. The frequency response spectrum contains a series of peaks whose positions and widths are determined by the composition of the gas and the geometry of the cylindrical resonator; the intensities are related to the gas pressure. Comparing observed gas frequencies with theory gives excellent agreement. Small changes in gas composition, better than 1:1000, are readily measurable.

  9. Approaches to assess biocover performance on landfills.

    PubMed

    Huber-Humer, M; Röder, S; Lechner, P

    2009-07-01

    Methane emissions from active or closed landfills can be reduced by means of methane oxidation enhanced in properly designed landfill covers, known as "biocovers". Biocovers usually consist of a coarse gas distribution layer to balance gas fluxes placed beneath an appropriate substrate layer. The application of such covers implies use of measurement methods and evaluation approaches, both during the planning stage and throughout the operation of biocovers in order to demonstrate their efficiency. Principally, various techniques, commonly used to monitor landfill surface emissions, can be applied to control biocovers. However, particularly when using engineered materials such as compost substrates, biocovers often feature several altered, specific properties when compared to conventional covers, e.g., respect to gas permeability, physical parameters including water retention capacity and texture, and methane oxidation activity. Therefore, existing measuring methods should be carefully evaluated or even modified prior to application on biocovers. This paper discusses possible strategies to be applied in monitoring biocover functionality. On the basis of experiences derived from investigations and large-scale field trials with compost biocovers in Austria, an assessment approach has been developed. A conceptual draft for monitoring biocover performance and recommendations for practical application are presented. PMID:19282167

  10. 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.

  11. 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...

  12. 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

  13. 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.

  14. 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.

  15. Method and apparatus for off-gas composition sensing

    DOEpatents

    Ottesen, David Keith; Allendorf, Sarah Williams; Hubbard, Gary Lee; Rosenberg, David Ezechiel

    1999-01-01

    An apparatus and method for non-intrusive collection of off-gas data in a steelmaking furnace includes structure and steps for transmitting a laser beam through the off-gas produced by a steelmaking furnace, for controlling the transmitting to repeatedly scan the laser beam through a plurality of wavelengths in its tuning range, and for detecting the laser beam transmitted through the off-gas and converting the detected laser beam to an electrical signal. The electrical signal is processed to determine characteristics of the off-gas that are used to analyze and/or control the steelmaking process.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Increasing the FOD tolerance of composites. [gas turbine engine blade foreign object damage

    NASA Technical Reports Server (NTRS)

    Novak, R. C.

    1978-01-01

    An experimental program was conducted for the purpose of increasing the foreign object damage tolerance of resin matrix composites in gas turbine engine fan blade applications. The superhybrid concept consisting of a resin matrix composite core surrounded by a sheath of boron/aluminum and titanium was found to be the most promising approach.

  4. Attenuation of methane and volatile organic compounds in landfill soil covers.

    PubMed

    Scheutz, Charlotte; Mosbaek, Hans; Kjeldsen, Peter

    2004-01-01

    The potential for natural attenuation of volatile organic compounds (VOCs) in landfill covers was investigated in soil microcosms incubated with methane and air, simulating the gas composition in landfill soil covers. Soil was sampled at Skellingsted Landfill at a location emitting methane. In total, 26 VOCs were investigated, including chlorinated methanes, ethanes, ethenes, fluorinated hydrocarbons, and aromatic hydrocarbons. The soil showed a high capacity for methane oxidation resulting in very high oxidation rates of between 24 and 112 microg CH4 g(-1) h(-1). All lower chlorinated compounds were shown degradable, and the degradation occurred in parallel with the oxidation of methane. In general, the degradation rates of the chlorinated aliphatics were inversely related to the chlorine to carbon ratios. For example, in batch experiments with chlorinated ethylenes, the highest rates were observed for vinyl chloride (VC) and lowest rates for trichloroethylene (TCE), while tetrachloroethylene (PCE) was not degraded. Maximal oxidation rates for the halogenated aliphatic compounds varied between 0.03 and 1.7 microg g(-1) h(-1). Fully halogenated hydrocarbons (PCE, tetrachloromethane [TeCM], chlorofluorocarbon [CFC]-11, CFC-12, and CFC-113) were not degraded in the presence of methane and oxygen. Aromatic hydrocarbons were rapidly degraded giving high maximal oxidation rates (0.17-1.4 microg g(-1) h(-1)). The capacity for methane oxidation was related to the depth of oxygen penetration. The methane oxidizers were very active in oxidizing methane and the selected trace components down to a depth of 50 cm below the surface. Maximal oxidation activity occurred in a zone between 15 and 20 cm below the surface, as this depth allowed sufficient supply of both methane and oxygen. Mass balance calculations using the maximal oxidation rates obtained demonstrated that landfill soil covers have a significant potential for not only methane oxidation but also cometabolic

  5. CHEMICAL COMPOSITION OF EXHAUST PARTICLES FROM GAS TURBINE ENGINES

    EPA Science Inventory

    A program was conducted to chemically characterize particulate emissions from a current technology, high population, gas turbine engine. Attention was focused on polynuclear aromatic compounds, phenols, nitrosamines and total organics. Polynuclear aromatic hydrocarbons (PAH) were...

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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%.

  12. 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

  13. 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.

  14. 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

  15. LANDFILL GAS CONSUMPTION IN RHIZOSPHERE OF ALTERNATIVE LANDFILL COVERS

    EPA Science Inventory

    The two identical 12 ft by 12 ft by 12 ft, polished stainless steel, insulated Environmental Chambers, located within the Testing and Evaluation (T&E) Facility, incorporate unique design features. Each chamber is equipped with 16 light fixtures containing a total of 32 light bulb...

  16. 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

  17. 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

  18. Leachate recirculation at the Nanticoke sanitary landfill using a bioreactor trench. Final report

    SciTech Connect

    Pagano, J.J.; Scrudato, R.J.; Sumner, G.M.

    1998-02-01

    A one-year landfill leachate recirculation demonstration project was conducted in a 20-acre cell at the Broome County, NY, Nanticoke Landfill using a retrofit bioreactor trench design concept to introduce landfill leachate to the surrounding refuse mass. Over the course of the project, 1.1 million gallons of landfill leachate were distributed through the bioreactor trench, substantially increasing the moisture content (approaching 70%) of the surrounding municipal solid waste. Experimental results also indicate that the bioreactor trench functioned as an in-situ anaerobic bioreactor, effectively treating landfill leachate retained within the trench due to decreasing refuse permeability and enhanced leachate hydraulic retention time. A significant and steady decline was noted in landfill leachate chemical oxygen demand (COD), volatile fatty acid (VFA), and total organic carbon (TOC), suggesting that the rapid biological stabilization of the refuse within the 20-acre demonstration area was influenced by the bioreactor trench. Characterization of the resulting landfill gas indicated that optimum methane:carbon dioxide ratios were measured in all experimental gas wells and in the bioreactor trench. No apparent enhancement of landfill gas production was noted in promixity to the bioreactor trench.

  19. 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

  20. 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.

  1. MONITORING APPROACHES FOR BIOREACTOR LANDFILLS

    EPA Science Inventory

    Experimental bioreactor landfill operations at operating Municipal Solid Waste (MSW) landfills can be approved under the research development and demonstration (RD&D) provisions of 40 CFR 258.4. To provide a basis for consistent data collection for future decision-making in suppo...

  2. MONITORING GUIDANCE FOR BIOREACTOR LANDFILLS

    EPA Science Inventory

    Experimental bioreactor landfill operations at operating Municipal Solid Waste (MSW) landfills can be approved under the research development and demonstration (RD&D) provisions of 30CFR 258.4. To provide a basis for consistent data collection for future decision-making in suppor...

  3. 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)

  4. 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

  5. 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).

  6. Isotope composition (C, H, O) and gas potential assessment in the South Caspian depression (Azerbaijan)

    NASA Astrophysics Data System (ADS)

    Poletayev, A. V.

    2009-04-01

    The large amount of HC isotope composition material of over 330 samples allows to study gas potential assessment within the South Caspian depression. Maps of isotope composition changes according to area extent, as well as graphs of HC distribution depending upon stratigraphic age including rocks, graphs of isotope composition change on sampling depth were compiled for HC study and oil-gas deposits formation. Comparison of mud volcanoes gases, oil and gas fields, gas-hydrates and bottom sediments was conducted. Gases genesis according to M. Shoelle and A. James methodic was studied. Model of area paleoconstruction was studied. Comparison of mud volcanoes gases with gases of oil fields within South Caspian depression shows that their isotope composition varies within the same ranges. Their difference is observed in chemical composition. Mud volcanoes gases are sharply impoverished by amount of heavy hydrocarbons. Study of isotope gases composition distribution in extent area allowed to distinguish zones and areas with different composition of heavy isotope. For example, in the deep-seated areas of the South Caspian depression toward flank zones of Low Kura depression as well some areas of Baku archipelago and Absheron peninsula gradually one can observe zones with a low content of heavy carbon isotope etc. Isotope gases composition depending upon stratigraphic age of including rocks has a certain peculiarities. From low to the upper section of PS as well as deposits of Cretaceous system toward chokrak regiostage (underlying PS deposits) one can observe increase of light carbon isotope. This fact allows to suppose that there exits two stages of HC formation. Comparison of HC gases isotope composition with sampling depth allowed to conclude that in the near-flank zones oil-gas deposits were re-formed by a large gas volumes the source of which was there same deposits within new thermobaric conditions. Gases of biochemical, diagenetic and thermocatalytic genesis etc

  7. Landfill to Learning Facility

    NASA Astrophysics Data System (ADS)

    Venner, L.; Lewicki, S.

    2008-11-01

    Engaging ``K-to-Gray'' audiences (children, families, and older adults) in scientific exploration and discovery is the main goal of the New Jersey Meadowlands Commission (NJMC) Center for Environmental and Scientific Education (CESE) and the William D. McDowell Observatory located in Lyndhurst, NJ and operated by Ramapo College of New Jersey. Perched atop a closed and reclaimed municipal solid waste landfill, our new LEED--certified building (certification pending) and William D. McDowell observatory brings hands-on scientific experiences to the ˜25,000 students and ˜15,000 visitors that come to our site from the NY/NJ region each year.

  8. 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.

  9. 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

  10. 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

  11. 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. PMID:22675306

  12. 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.

  13. 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

  14. 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. PMID:12220829

  15. 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.

  16. 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.

  17. 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. PMID:11530917

  18. 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

  19. Determination of gas composition in a biogas plant using a Raman-based sensor system

    NASA Astrophysics Data System (ADS)

    Eichmann, S. C.; Kiefer, J.; Benz, J.; Kempf, T.; Leipertz, A.; Seeger, T.

    2014-07-01

    We propose a gas sensor, based on spontaneous Raman scattering, for the compositional analysis of typical biogas mixtures and present a description of the sensor, as well as of the calibration procedure, which allows the quantification of condensable gases. Moreover, we carry out a comprehensive characterization of the system, in order to determine the measurement uncertainty, as well as influences of temperature and pressure fluctuation. Finally, the sensor is applied at different locations inside a plant in which biogas is produced from renewable raw materials. The composition is monitored after fermenting, after purification and after the final conditioning, where natural gas is added. The Raman sensor is able to detect all the relevant gas components, i.e. CH4, CO2, N2 and H2O, and report their individual concentrations over time. The results were compared to reference data from a conventional gas analyzer and good agreement was obtained.

  20. Gas7-Deficient Mouse Reveals Roles in Motor Function and Muscle Fiber Composition during Aging

    PubMed Central

    Huang, Bo-Tsang; Chang, Pu-Yuan; Su, Ching-Hua; Chao, Chuck C.-K.; Lin-Chao, Sue

    2012-01-01

    Background Growth arrest-specific gene 7 (Gas7) has previously been shown to be involved in neurite outgrowth in vitro; however, its actual role has yet to be determined. To investigate the physiological function of Gas7 in vivo, here we generated a Gas7-deficient mouse strain with a labile Gas7 mutant protein whose functions are similar to wild-type Gas7. Methodology/Principal Findings Our data show that aged Gas7-deficient mice have motor activity defects due to decreases in the number of spinal motor neurons and in muscle strength, of which the latter may be caused by changes in muscle fiber composition as shown in the soleus. In cross sections of the soleus of Gas7-deficient mice, gross morphological features and levels of myosin heavy chain I (MHC I) and MHC II markers revealed significantly fewer fast fibers. In addition, we found that nerve terminal sprouting, which may be associated with slow and fast muscle fiber composition, was considerably reduced at neuromuscular junctions (NMJ) during aging. Conclusions/Significance These findings indicate that Gas7 is involved in motor neuron function associated with muscle strength maintenance. PMID:22662195

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. High performance fibers for structurally reliable metal and ceramic composites. [advanced gas turbine engine materials

    NASA Technical Reports Server (NTRS)

    Dicarlo, J. A.

    1984-01-01

    Very few of the commercially available high performance fibers with low densities, high Young's moduli, and high tensile strengths possess all the necessary property requirements for providing either metal matrix composites (MMC) or ceramic matrix composites (CMC) with high structural reliability. These requirements are discussed in general and examples are presented of how these property guidelines are influencing fiber evaluation and improvement studies at NASA aimed at developing structurally reliable MMC and CMC for advanced gas turbine engines.

  8. 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.

  9. 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.

  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. Calibration of the U.S. EPA`s landfill air emissions estimation model for dispersion modelling of vinyl chloride at municipal landfills

    SciTech Connect

    Alberico, J.J.; Handy, B.; Chadder, D.S.

    1997-12-31

    Ambient air quality monitoring programs of vinyl chloride have been conducted at two municipal landfills -- Eastview and Britannia -- in Ontario, Canada. These programs were designed to provide actual data as a basis for better estimating impacts of vinyl chloride emitted from the landfills on the surrounding environment. Dispersion modelling was conducted to replicate vinyl chloride levels measured during the sampling programs. This was accomplished by using the vinyl chloride emission rates determined by the US EPA`s Landfill Air Emissions Estimation Model and modelling the same meteorological conditions and sampling locations recorded during the monitoring program. This emissions model is known to produce conservative estimates of gas emissions from landfills. Predicted vinyl chloride levels were generally much higher than the measured values at both landfill sites. Based on statistical comparisons of the data sets, it was found that predicted vinyl chloride levels were 4 and 51 times higher than levels measured at the Eastview and Britannia Landfill sites, respectively. These reduction factors were applied to the emission rates estimated by the emissions model and the predicted impacts were re-assessed. These reduction factors ensure a more realistic prediction of vinyl chloride levels but still ensure that the predicted levels were generally higher than the measured levels. The air quality impact, when generated using the adjusted model, indicated no need for mitigation measures such as landfill gas collection and destruction.

  12. 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.

  13. Venus lower atmospheric composition - Analysis by gas chromatography

    NASA Technical Reports Server (NTRS)

    Oyama, V. I.; Carle, G. C.; Woeller, F.; Pollack, J. B.

    1979-01-01

    The first gas chromatographic analysis of the lower atmosphere of Venus is reported. Three atmospheric samples were analyzed. The third of these samples showed carbon dioxide (96.4 percent), molecular nitrogen (3.41 percent), water vapor (0.135 percent), molecular oxygen (69.3 ppm), argon (18.6 ppm), neon (4.31 ppm), and sulfur dioxide (186 ppm). The amounts of water vapor and sulfur dioxide detected are roughly compatible with the requirements of greenhouse models of the high surface temperature of Venus. The large positive gradient of sulfur dioxide, molecular oxygen, and water vapor from the cloud tops to their bottoms, as implied by Earth-based observations and these results, gives added support for the presence of major quantities of aqueous sulfuric acid in the clouds. A comparison of the inventory of inert gases found in the atmospheres of Venus, Earth, and Mars suggests that these components are due to outgassing from the planetary interiors.

  14. Composite Matrix Cooling Scheme for Small Gas Turbine Combustors

    NASA Technical Reports Server (NTRS)

    Paskin, Marc D.; Ross, Phillip T.; Mongia, Hukam C.; Acosta, Waldo A.

    1990-01-01

    The design, manufacture, and testing of a compliant metal/ceramic (CMC) wall cooling concept-implementing combustor for small gas turbine engines has been undertaken by a joint U.S. Army/NASA technology development program. CMC in principle promises greater wall cooling effectiveness than conventional designs and materials, thereby facilitating a substantial reduction in combustor cooling air requirements and furnishing greater airflow for the control of burner outlet temperature patterns as well as improving thermodynamic efficiency and reducing pollutant emissions and smoke levels. Rig test results have confirmed the projected benefits of the CMC concept at combustor outlet temperatures of the order of 2460 F, at which approximately 80 percent less cooling air than conventionally required was being employed by the CMC combustor.

  15. Development of ceramic composite hot-gas filters

    SciTech Connect

    Judkins, R.R.; Stinton, D.P.; Smith, R.G.; Fischer, E.M.; Eaton, J.H.; Weaver, B.L.; Kahnke, J.L.; Pysher, D.J.

    1995-04-01

    A novel type of hot-gas filter based on a ceramic fiber-reinforced ceramic matrix was developed and extended to fullsize, 60-mm OD by 1.5-meter-long, candle filters. A commercially viable process for producing the filters was developed, and the filters are undergoing testing and demonstration throughout the world for applications in pressurized fluidized-bed combustion (PFBC) and integrated gasification combined cycle (IGCC) plants. Development activities at Oak Ridge National Laboratory (ORNL) and at the 3M Company, and testing at the Westinghouse Science and Technology Center (STC) are presented. Demonstration tests at the Tidd PFBC are underway. Issues identified during the testing and demonstration phases of the development are discussed. Resolution of the issues and the status of commercialization of the filters are described.

  16. Astronomy on a Landfill

    NASA Astrophysics Data System (ADS)

    Venner, L.

    2008-11-01

    Engaging ``K-to-Gray'' audiences (children, families, and older adults) in astronomical activities is one of the main goals of the New Jersey Meadowlands Commission Center for Environmental and Scientific Education (CESE) and the William D. McDowell Observatory located in Lyndhurst, NJ, operated by Ramapo College of New Jersey. Perched atop a closed and reclaimed municipal solid waste landfill, our new LEED--certified building (certification pending) and William D. McDowell observatory will assist in bringing the goals of the International Year of Astronomy 2009 (IYA2009) to the ˜25,000 students and ˜15,000 visitors that visit our site from the NY/NJ region each year.

  17. Hydroxyl radical (OH) scavenging in young and mature landfill leachates.

    PubMed

    Ghazi, Niloufar M; Lastra, Andres A; Watts, Michael J

    2014-06-01

    The final discharge point for collected landfill leachates is frequently the local municipal wastewater treatment facility. The salinity, color, nutrient, and anthropogenic organics contamination of leachates often necessitate some form of pre-treatment. When advanced oxidation processes (AOPs) are considered for pre-treatment, the unique composition of dissolved organic matter (DOM) and the relatively high concentrations of some inorganic solutes in leachate will inhibit treatment efficiency. The most important benchmark for design of AOPs is the expected steady-state production of free radical (OH). Without a quantitative assessment of total OH consumption in high-strength waste water, like a landfill leachate, efficient AOP treatment is uncertain. For this reason, two landfill leachates, distinct in color, DOM, and age of landfill, were characterized for OH-scavenging using an established competition kinetics method. After stripping the samples of inorganic carbon, the DOM in leachate from mature (stabilized) landfill was found to react with OH at a rate of 9.76 × 10(8) M(-1)s(-1). However, DOM in leachate from newer landfill was observed to scavenge available OH at a faster rate (8.28 × 10(9) M(-1)s(-1)). The combination of fast rate of reaction with OH and abundance of DOM in the sampled leachate severely limited the contribution of OH to degradation of an O3- and OH-labile organic probe compound (bisphenol-a) in oxidized mature leachate (fOH = 0.03). Substantial dosing of both O3 and H2O2 (>70 mg/L and >24 mg/L, respectively) may be required to see at least 1-log-removal (>90%) of an OH-selective leachate contaminant (i.e., parachlorobenzoic acid) in a mature landfill leachate. PMID:24675270

  18. Ammonia Gas Sensing Behavior of Tanninsulfonic Acid Doped Polyaniline-TiO2 Composite

    PubMed Central

    Bairi, Venu Gopal; Bourdo, Shawn E.; Sacre, Nicolas; Nair, Dev; Berry, Brian C.; Biris, Alexandru S.; Viswanathan, Tito

    2015-01-01

    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. PMID:26501291

  19. 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

    2015-01-01

    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. PMID:26501291

  20. Optimization and analysis of mixed refrigerant composition for the PRICO natural gas liquefaction process

    NASA Astrophysics Data System (ADS)

    Xu, Xiongwen; Liu, Jinping; Cao, Le

    2014-01-01

    In this paper, the energy optimization of the PRICO natural gas liquefaction (LNG) process was performed with the genetic algorithm (GA) and the process simulation software Aspen Plus. Then the characteristics of the heat transfer composite curves of the cold box were obtained and analyzed. Based on it, the heat exchange process in the cold box was divided into three regions. At last, in order to find the relationship between the energy consumption and the composition of the mixed refrigerant, the effects of the refrigerant flow composition on the temperature difference and the pinch point location were deeply investigated, which would be useful to guide the refrigerant charging.

  1. Temperature dependence of gas sensing behaviour of TiO{sub 2} doped PANI composite thin films

    SciTech Connect

    Srivastava, Subodh Sharma, Preetam; Singh, M.; Vijay, Y. K.; Sharma, S. S.; Sharma, Vinay; Rajura, Rajveer Singh

    2014-04-24

    In the present work we have reported the effect of temperature on the gas sensing properties of TiO{sub 2} doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and TiO{sub 2} doped PANI composite were synthesized by in situ chemical oxidative polymerization of aniline at low temperature. The electrical properties of these composite thin films were characterized by I-V measurements as function of temperature. The I-V measurement revealed that conductivity of composite thin films increased as the temperature increased. The changes in resistance of the composite thin film sensor were utilized for detection of hydrogen gas. It was observed that at room temperature TiO{sub 2} doped PANI composite sensor shows higher response value and showed unstable behavior as the temperature increased. The surface morphology of these composite thin films has also been characterized by scanning electron microscopy (SEM) measurement.

  2. Characterization of thermal properties of municipal solid waste landfills.

    PubMed

    Faitli, József; Magyar, Tamás; Erdélyi, Attila; Murányi, Attila

    2015-02-01

    Municipal waste landfills represent not only a source of landfill gases, but a source of thermal energy as well. The heat in landfills is generated by physical, chemical and microbiological processes. The goal of our study was to characterize the thermal properties of municipal solid waste (MSW) samples of the given landfill. A new apparatus was designed and constructed to measure heat flow. A systematic test series of 17 discrete measurements was carried out with municipal waste samples of 1.0-1.7 m(3). The thermal conductivity, heat diffusivity and specific heat capacity of the samples were determined. Analysing the results of the sampling and our experiments it was realized that the theoretical fundaments should be clarified. Two theories were developed for the serial and for the parallel heat flow in three phase disperse systems. The serial and parallel models resulted in different theoretical estimations. The measured thermal conductivity and heat diffusivity were better characterized by the parallel heat flow estimations. The results show that heat can flow parallel in solid, liquid and gas phases. Characterization of thermal properties serves to establish the fundament of heat extraction from municipal waste landfills. PMID:25464944

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

    SciTech Connect

    Don Augenstein

    2001-02-01

    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 landfills. This is the highest methane recovery rate per unit waste, and thus progress toward stabilization, documented anywhere for such a large waste mass. This high recovery rate is attributed to moisture, and elevated temperature attained inexpensively during startup. Economic analyses performed under Phase I of this NETL contract indicate ''greenhouse cost effectiveness'' to be excellent. Other benefits include substantial waste volume loss (over 30%) which translates to extended landfill life. Other environmental benefits include rapidly improved quality and stabilization (lowered pollutant levels) in liquid leachate which drains from the waste.

  4. Composite thermochemistry of gas phase U(VI)-containing molecules

    SciTech Connect

    Bross, David H.; Peterson, Kirk A.

    2014-12-28

    Reaction energies have been calculated for a series of reactions involving UF{sub 6}, UO{sub 3}, UO{sub 2}(OH){sub 2}, and UO{sub 2}F{sub 2} using coupled cluster singles and doubles with perturbative triples, CCSD(T), with a series of correlation consistent basis sets, including newly developed pseudopotential (PP)- and all-electron (AE) Douglas-Kroll-Hess-based sets for the U atom. The energies were calculated using a Feller-Peterson-Dixon composite approach in which CCSD(T) complete basis set (CBS) limits were combined with a series of additive contributions for spin-orbit coupling, outer-core correlation, and quantum electrodynamics effects. The calculated reaction enthalpies (both PP and AE) were combined with the accurately known heat of formation of UF{sub 6} to determine the enthalpies of formation of UO{sub 3}, UO{sub 2}(OH){sub 2}, and UO{sub 2}F{sub 2}. The contribution to the reaction enthalpies due to correlation of the 5s5p5d electrons of U was observed to be very slowly convergent with basis set and at the CBS limit their impact on the final enthalpies was on the order of 1 kcal/mol or less. For these closed shell molecules, spin-orbit effects contributed about 1 kcal/mol to the final enthalpies. Interestingly, the PP and AE approaches yielded quite different spin-orbit contributions (similar magnitude but opposite in sign), but the total scalar plus spin-orbit results from the two approaches agreed to within ∼1 kcal/mol of each other. The final composite heat of formation for UO{sub 2}F{sub 2} was in excellent agreement with experiment, while the two results obtained for UO{sub 3} were just outside the ±2.4 kcal/mol error bars of the currently recommended experimental value. An improved enthalpy of formation (298 K) for UO{sub 2}(OH){sub 2} is predicted from this work to be −288.7 ± 3 kcal/mol, compared to the currently accepted experimental value of −292.7 ± 6 kcal/mol.

  5. Composite thermochemistry of gas phase U(VI)-containing molecules.

    PubMed

    Bross, David H; Peterson, Kirk A

    2014-12-28

    Reaction energies have been calculated for a series of reactions involving UF6, UO3, UO2(OH)2, and UO2F2 using coupled cluster singles and doubles with perturbative triples, CCSD(T), with a series of correlation consistent basis sets, including newly developed pseudopotential (PP)- and all-electron (AE) Douglas-Kroll-Hess-based sets for the U atom. The energies were calculated using a Feller-Peterson-Dixon composite approach in which CCSD(T) complete basis set (CBS) limits were combined with a series of additive contributions for spin-orbit coupling, outer-core correlation, and quantum electrodynamics effects. The calculated reaction enthalpies (both PP and AE) were combined with the accurately known heat of formation of UF6 to determine the enthalpies of formation of UO3, UO2(OH)2, and UO2F2. The contribution to the reaction enthalpies due to correlation of the 5s5p5d electrons of U was observed to be very slowly convergent with basis set and at the CBS limit their impact on the final enthalpies was on the order of 1 kcal/mol or less. For these closed shell molecules, spin-orbit effects contributed about 1 kcal/mol to the final enthalpies. Interestingly, the PP and AE approaches yielded quite different spin-orbit contributions (similar magnitude but opposite in sign), but the total scalar plus spin-orbit results from the two approaches agreed to within ∼1 kcal/mol of each other. The final composite heat of formation for UO2F2 was in excellent agreement with experiment, while the two results obtained for UO3 were just outside the ±2.4 kcal/mol error bars of the currently recommended experimental value. An improved enthalpy of formation (298 K) for UO2(OH)2 is predicted from this work to be -288.7 ± 3 kcal/mol, compared to the currently accepted experimental value of -292.7 ± 6 kcal/mol. PMID:25554152

  6. Tracking Gas Phase Composition in Oil evaporation and Oxidation Experiments

    NASA Astrophysics Data System (ADS)

    Amador-Muñoz, O.; Zhang, H.; Misztal, P. K.; Worton, D.; Drozd, G.; Goldstein, A. H.

    2015-12-01

    Primary Organic Aerosol (POA) is emitted directly by anthropogenic or natural sources, whereas Secondary Organic Aerosol (SOA) is formed in the atmosphere through chemical reactions that result from conversion of more volatile species into lower volatility oxidized products and their subsequent condensation to the particulate phase. We studied SOA formation from evaporation of Macondo crude oil (MC 252) using a wind tunnel coupled to a flow tube oxidation reactor. Ozone, UV lights, and water vapor were used to make OH radicals. Organic compounds in the gas phase, both those evaporated from the wind tunnel and those formed in the flow tube oxidation experiments, were monitored using proton-transfer-reaction mass spectrometry (PTR-qMS and PTR-TOF-MS). We observed approximately 400 different species. Compounds with less than C10 were mostly evaporated in the first 5 hours when maximum SOA formation was also obtained. Hydrocarbons with carbon number (11-14) were still present in the oil after 12 h of continuous evaporation at wind speed of 2 m s-1. We will show the implications of these results for the production of SOA related to the range of evaporated chemical size and reactivity.

  7. 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

    The application of ceramics to gas turbine combustor liners to reduce liner metal temperature was studied in an experiment in which yttria-stabilized zirconia plasma was sprayed on compliant metal substrates exposed to near stoichiometric combustion. The strain isolation pad materials chosen were Hoskins Alloy 875 and BRUNSLLOY 534 Fiber Metal of 0.25 and 0.38 cm thicknesses and 35 and 45 percent density levels. Combustor screening tests of all specimens showed no evidence of deterioration or failure. Specimens exposed to flame temperatures in excess of 2100 K were convectively or convective-transpiration cooled and were evaluated in a 10 cm sq flame tube at inlet air temperature of 533 K and pressure of 0.5 MPa. The results suggest the superiority of a system composed of the Hoskins Alloy 875 compliant pad with 0.25 cm thickness and 35 percent density coupled with a NiCrAlY bond coat and a 8 percent Y2O3-ZrO2 ceramic top coat of 0.19 cm thickness.

  8. Venus lower atmospheric composition: analysis by gas chromatography.

    PubMed

    Oyama, V I; Carle, G C; Woeller, F; Pollack, J B

    1979-02-23

    The first gas chromatographic analysis of the lower atmosphere of Venus is reported. Three atmospheric samples were analyzed. The third of these samples showed carbon dioxide (96.4 percent), molecular nitrogen (3.41 percent), water vapor (0.135 percent), molecular oxygen [69.3 parts per million (ppm)], argon (18.6 ppm), neon (4.31 ppm), and sulfuir dioxide (186 ppm). The amounts of water vapor and sulfur dioxide detected are roughly compatible with the requirements of greenhouse models of the high surface temperature of Venus. The large positive gradient of sulfur dioxide, molecular oxygen, and water vapor from the clould tops to their bottoms, as implied by Earth-based observations and these resuilts, gives added support for the presence of major quantities of aqueous sulfuric acid in the clouds. A comparison of the inventory of inert gases found in the atmospheres of Venus, Earth, and Mars suggests that these components are due to outgassing from the planetary interiors. PMID:17833004

  9. Where Should the Landfill Go?

    ERIC Educational Resources Information Center

    Fazio, Rosario P.; McFaden, Dennis

    1993-01-01

    Describes a project where students were involved in finding the most suitable site for a landfill in their community. This two-month project was conducted using team teaching. Two twelfth grade geoscience classes were involved. (PR)

  10. Sanitary landfill groundwater monitoring report

    SciTech Connect

    Not Available

    1993-02-01

    The Sanitary Landfill at the Savannah River Site (SRS) is composed of the original 32-acre landfill, plus expansion areas to the north and south that added 16 and 22 acres, respectively, to the facility. The landfill is subject to the requirements of the Resource Conservation and Recovery Act and currently operates under South Carolina Department of Health and Environmental Control (SCDHEC) Domestic Waste Permit 87A. Fifty-seven wells of the LFW series monitor the groundwater quality in Steed Pond Aquifer (formerly Aquifer Zone I/IIC[sub 2]) (Water Table) beneath the Sanitary Landfill. These wells are sampled quarterly for certain indicator parameters, inorganics, metals, radionuclides, volatile organics, and other constituents as part of the SRS Groundwater Monitoring Program and to comply with the SCDHEC domestic waste permit. This report reviews the 1992 activities of the SRS Groundwater Monitoring Program.

  11. LANDFILL CONTAINMENT AND COVER SYSTEMS

    EPA Science Inventory

    The U.S. Environmental Protection Agency through its research and field experiences has developed control strategies for hazardous and municipal solid waste landfills and surface impoundments. hese control strategies include liner and cover systems. he liner systems include doubl...

  12. Evolution of natural gas composition: Predictive multi-phase reaction-transport modeling

    SciTech Connect

    Ortoleva, P.J.; Chang, K.A.; Maxwell, J.M.

    1995-12-31

    A computational modeling approach is used to investigate reaction and transport processes affecting natural gas composition over geological time. Three basic stages are integrated -- gas generation from organic solids or liquids, interactions during source rock expulsion to the reservoir and reactions within the reservoir. Multi-phase dynamics is handled by solving the fully coupled problem of phase-to-phase transfer, intra-phase organic and inorganic reactions and redox and other reactions between fluid phase molecules and minerals. Effects of capillarity and relative permeability are accounted for. Correlations will be determined between gas composition, temperature history, the mineralogy of rocks with which the gas was in contact and the composition of source organic phases. Questions of H{sub 2}S scavenging by oxidizing minerals and the production or removal of CO{sub 2} are focused upon. Our three spatial dimensional, reaction-transport simulation approach has great promise for testing general concepts and as a practical tool for the exploration and production of natural gas.

  13. Hydrogen Gas Sensing Characteristics of Multiwalled Carbon Nanotubes Based Hybrid Composites

    NASA Astrophysics Data System (ADS)

    Dhall, Shivani; Jaggi, Neena

    2016-01-01

    In the present work, hydrogen (H2) gas sensing characteristics of hybrid composites prepared by sputtering of platinum (Pt) metal on the synthesized composites of functionalized multiwalled carbon nanotubes (F-MWCNTs) with selective metal oxides (nickel oxide and cuprous oxide) have been investigated. Both of these sensors are found to have fast response, complete resistance recovery, and good baseline stability at room temperature (25°C). These sensors stably and reversibly respond to 0.05% concentration of H2 gas at 25°C. This sensing material was characterized by x-ray diffraction, Raman spectroscopy ,and scanning electron microscopy. To the best of our knowledge, detection of such low concentration of H2 gas is reported here for the first time using F-MWCNTs/NiO/Pt and F-MWCNTs/Cu2O/Pt hybrid nanostructures at 25°C.

  14. Development and evaluation of a silver mordenite composite sorbent for the partitioning of xenon from krypton in gas compositions

    DOE PAGESBeta

    Garn, Troy G.; Greenhalgh, Mitchell; Law, Jack D.

    2015-12-22

    A new engineered form composite sorbent for the selective separation of xenon from krypton in simulant composition off-gas streams resulting from the reprocessing of used nuclear fuel has been developed and evaluated. A sodium mordenite powder was incorporated into a macroporous polymer binder, formed into spherical beads and successfully converted to a 9 wt.% silver form composite sorbent. The final engineered form sorbent retained the characteristic surface area indicative of sodium mordenite powder. The sorbent was evaluated for xenon adsorption potential with capacities measured as high as 30 millimoles of xenon per kilogram of sorbent achieved at ambient temperature andmore » 460 millimoles of xenon per kilogram sorbent at 220 K. Xenon/krypton selectivity was calculated to be 22.4 with a 1020 µL/L xenon, 150 µL/L krypton in a balance of air feed gas at 220 K. Furthermore, adsorption/desorption thermal cycling effects were evaluated with results indicating sorbent performance was not significantly impacted while undergoing numerous adsorption/desorption thermal cycles.« less

  15. Development and evaluation of a silver mordenite composite sorbent for the partitioning of xenon from krypton in gas compositions

    SciTech Connect

    Garn, Troy G.; Greenhalgh, Mitchell; Law, Jack D.

    2015-12-22

    A new engineered form composite sorbent for the selective separation of xenon from krypton in simulant composition off-gas streams resulting from the reprocessing of used nuclear fuel has been developed and evaluated. A sodium mordenite powder was incorporated into a macroporous polymer binder, formed into spherical beads and successfully converted to a 9 wt.% silver form composite sorbent. The final engineered form sorbent retained the characteristic surface area indicative of sodium mordenite powder. The sorbent was evaluated for xenon adsorption potential with capacities measured as high as 30 millimoles of xenon per kilogram of sorbent achieved at ambient temperature and 460 millimoles of xenon per kilogram sorbent at 220 K. Xenon/krypton selectivity was calculated to be 22.4 with a 1020 µL/L xenon, 150 µL/L krypton in a balance of air feed gas at 220 K. Furthermore, adsorption/desorption thermal cycling effects were evaluated with results indicating sorbent performance was not significantly impacted while undergoing numerous adsorption/desorption thermal cycles.

  16. Thermal performance of multilayer insulations. [gas evacuation characteristics of three selected multilayer insulation composites

    NASA Technical Reports Server (NTRS)

    Keller, C. W.; Cunnington, G. R.; Glassford, A. P.

    1974-01-01

    Experimental and analytical studies were conducted in order to extend previous knowledge of the thermal performance and gas evacuation characteristics of three selected multilayer insulation (MLI) composites. Flat plate calorimeter heat flux measurements were obtained for 20- and 80- shield specimens using three representative layer densities over boundary temperatures ranging from 39 K (70 R) to 389 K (700 R). Laboratory gas evacuation tests were performed on representative specimens of each MLI composite after initially purging them with helium, nitrogen, or argon gases. In these tests, the specimens were maintained at temperatures between 128 K (230 R) and 300 K (540 R). Based on the results of the laboratory-scale tests, a composite MLI system consisting of 112 unperforated, double-aluminized Mylar reflective shields and 113 water preconditioned silk net spacer pairs was fabricated and installed on a 1.22-m-(4-ft-) diameter calorimeter tank.

  17. Potential for enhanced phytoremediation of landfills using biosolids--a review.

    PubMed

    Kim, Kwon-Rae; Owens, Gary

    2010-01-01

    Despite the use of recyclable materials increasing worldwide, waste disposal to landfill remains the most common method of waste management because it is simple and relatively inexpensive. Although landfill disposal is an effective waste management system, if not managed correctly, a number of potential detrimental environmental impacts have been identified including soil and ground water contamination, leachate generation, and gas emissions. In particular, improper post-closure treatment of landfills or deterioration of the conventional clay landfill capping were shown to result in land degradation which required remediation to secure contaminants within the landfill site. Phytoremediation is an attractive technology for landfill remediation, as it can stabilize soil and simultaneously remediate landfill leachate. In addition, landfill phytoremediation systems can potentially be combined with landfill covers (Phytocapping) for hydrological control of infiltrated rainfall. However, for the successful application of any phytoremediation system, the effective establishment of appropriate, desired vegetation is critical. This is because the typically harsh and sterile nature of landfill capping soil limits the sustainable establishment of vegetation. Therefore, the physicochemical properties of landfill capping soils often need to be improved by incorporating soil amendments. Biosolids are a common soil amendment and will often meet these demanding conditions because they contain a variety of plant nutrients such as nitrogen, phosphate, potassium, as well as a large proportion of organic matter. Such amendment will also ameliorate the physical properties of the capping soils by increasing porosity, moisture content, and soil aggregation. Contaminants which potentially originate from biosolids will also be remediated by activities congruent with the establishment of plants and bacteria. PMID:19939550

  18. Enhanced Landfill Mining case study: Innovative separation techniques

    NASA Astrophysics Data System (ADS)

    Cuyvers, Lars; Moerenhout, Tim; Helsen, Stefan; Van de Wiele, Katrien; Behets, Tom; Umans, Luk; Wille, Eddy

    2014-05-01

    In 2011, a corporate vision on Enhanced Landfill Mining (ELFM)1 was approved by the OVAM Board of directors, which resulted in an operational programme over the period 2011-2015. OVAM (Public Waste Agency of Flanders) is the competent authority in charge of waste, Sustainable Materials Management (SMM) and contaminated soil management in Flanders. The introduction of the ELFM concept needs to be related with the concept of SMM and the broader shift to a circular economy. Within the concept of ELFM, landfills are no longer considered to be a final and static situation, but a dynamic part of the materials cycle. The main goal of this research programme is to develop a comprehensive policy on resource management to deal with the issue of former landfills. In order to investigate the opportunities of ELFM, the OVAM is applying a three step approach including mapping, surveying and mining of these former landfills. As a result of the mapping part over 2,000 landfill sites, that will need to be dealt with, were revealed. The valorisation potential of ELFM could be assigned to different goals, according to the R³P-concept : Recycling of Materials, Recovery of Energy, Reclamation of Land and Protection of drinking water supply. . On behalf of the OVAM, ECOREM was assigned to follow-up a pilot case executed on a former landfill, located in Zuienkerke, Flanders. Within this case study some technical tests were carried out on the excavated waste material to investigate the possibilities for a waste to resource conversion. The performance of both on site and off site techniques were evaluated. These testings also contribute to the mapping part of OVAM's research programme on ELFM and reveal more information on the composition of former landfills dating from different era's. In order to recover as many materials as possible, five contractors were assigned to perform separation tests on the bulk material from the Zuienkerke landfill. All used techniques were described

  19. Integrating remediation and resource recovery: On the economic conditions of landfill mining

    SciTech Connect

    Frändegård, Per Krook, Joakim; Svensson, Niclas

    2015-08-15

    Highlights: • We compare two remediation scenarios; one with resource recovery and one without. • Economic analysis includes relevant direct costs and revenues for the landfill owner. • High degrees of metal and/or combustible contents are important economic factors. • Landfill tax and the access to a CHP can have a large impact on the result. • Combining landfill mining and remediation may decrease the project cost. - Abstract: This article analyzes the economic potential of integrating material separation and resource recovery into a landfill remediation project, and discusses the result and the largest impact factors. The analysis is done using a direct costs/revenues approach and the stochastic uncertainties are handled using Monte Carlo simulation. Two remediation scenarios are applied to a hypothetical landfill. One scenario includes only remediation, while the second scenario adds resource recovery to the remediation project. Moreover, the second scenario is divided into two cases, case A and B. In case A, the landfill tax needs to be paid for re-deposited material and the landfill holder does not own a combined heat and power plant (CHP), which leads to disposal costs in the form of gate fees. In case B, the landfill tax is waived on the re-deposited material and the landfill holder owns its own CHP. Results show that the remediation project in the first scenario costs about €23/ton. Adding resource recovery as in case A worsens the result to −€36/ton, while for case B the result improves to −€14/ton. This shows the importance of landfill tax and the access to a CHP. Other important factors for the result are the material composition in the landfill, the efficiency of the separation technology used, and the price of the saleable material.

  20. Onsite survey on the mechanism of passive aeration and air flow path in a semi-aerobic landfill.

    PubMed

    Matsuto, Toshihiko; Zhang, Xin; Matsuo, Takayuki; Yamada, Shuhei

    2015-02-01

    The semi-aerobic landfill is a widely accepted landfill concept in Japan because it promotes stabilization of leachates and waste via passive aeration without using any type of mechanical equipment. Ambient air is thought to be supplied to the landfill through a perforated pipe network made of leachate collection pipe laid along the bottom and a vertically erected gas vent. However, its underlying air flow path and driving forces are unclear because empirical data from real-world landfills is inadequate. The objective of this study is to establish scientific evidence about the aeration mechanisms and air flow path by an on-site survey of a full-scale, semi-aerobic landfill. First, all passive vents located in the landfill were monitored with respect to temperature level and gas velocity in different seasons. We found a linear correlation between the outflow rate and gas temperature, suggesting that air flow is driven by a buoyancy force caused by the temperature difference between waste in the landfill and the ambient temperature. Some vents located near the landfill bottom acted as air inflow vents. Second, we conducted a tracer test to determine the air flow path between two vents, by injecting tracer gas from an air sucking vent. The resulting slowly increasing gas concentration at the neighboring vent suggested that fresh air flow passes through the waste layer toward the gas vents from leachate collection pipes, as well as directly flowing through the pipe network. Third, we monitored the temperature of gas flowing out of a vent at night. Since the temperature drop of the gas was much smaller than that of the environment, the air collected at the gas vents was estimated to flow mostly through the waste layer, i.e., the semi-aerobic landfill has considerable aeration ability under the appropriate conditions. PMID:25443098

  1. Background Information Document for Updating AP42 Section 2.4 for Estimating Emissions from Municipal Solid Waste Landfills

    EPA Science Inventory

    This revised draft document was prepared for U.S. EPA's Office of Research and Development, and describes the data analysis undertaken to update the Municipal Solid Waste (MSW) Landfill section of AP-42. This 2008 update includes the addition of data from 62 landfill gas emission...

  2. Landfill aeration in the framework of a reclamation project in Northern Italy.

    PubMed

    Raga, Roberto; Cossu, Raffaello

    2014-03-01

    In situ aeration by means of the Airflow technology was proposed for landfill conditioning before landfill mining in the framework of a reclamation project in Northern Italy. A 1-year aeration project was carried out on part of the landfill with the objective of evaluating the effectiveness of the Airflow technology for landfill aerobization, the evolution of waste biological stability during aeration and the effects on leachate and biogas quality and emissions. The main outcomes of the 1-year aeration project are presented in the paper. The beneficial effect of the aeration on waste biological stability was clear (63% reduction of the respiration index); however, the effectiveness of aeration on the lower part of the landfill is questionable, due to the limited potential for air migration into the leachate saturated layers. During the 1-year in situ aeration project approx. 275 MgC were discharged from the landfill body with the extracted gas, corresponding to 4.6 gC/kgDM. However, due to the presence of anaerobic niches in the aerated landfill, approx. 46% of this amount was extracted as CH4, which is higher than reported in other aeration projects. The O2 conversion quota was lower than reported in other similar projects, mainly due to the higher air flow rates applied. The results obtained enabled valuable recommendations to be made for the subsequent application of the Airflow technology to the whole landfill. PMID:24411985

  3. Bio-tarp alternative daily cover prototypes for methane oxidation atop open landfill cells.

    PubMed

    Adams, Bryn L; Besnard, Fabien; Bogner, Jean; Hilger, Helene

    2011-05-01

    Final landfill covers are highly engineered to prevent methane release into the atmosphere. However, methane production begins soon after waste placement and is an unaddressed source of emissions. The methane oxidation capacity of methanotrophs embedded in a "bio-tarp" was investigated as a means to mitigate methane release from open landfill cells. The bio-tarp would also serve as an alternative daily cover during routine landfill operation. Evaluations of nine synthetic geotextiles identified two that would likely be suitable bio-tarp components. Pilot tarp prototypes were tested in continuous flow systems simulating landfill gas conditions. Multilayered bio-tarp prototypes consisting of alternating layers of the two geotextiles were found to remove 16% of the methane flowing through the bio-tarp. The addition of landfill cover soil, compost, or shale amendments to the bio-tarp increased the methane removal up to 32%. With evidence of methane removal in a laboratory bioreactor, prototypes were evaluated at a local landfill using flux chambers installed atop intermediate cover at a landfill. The multilayered bio-tarp and amended bio-tarp configurations were all found to decrease landfill methane flux; however, the performance efficacy of bio-tarps was not significantly different from controls without methanotrophs. Because highly variable methane fluxes at the field site likely confounded the test results, repeat field testing is recommended under more controlled flux conditions. PMID:21354776

  4. PRACTICE REVIEW OF FIVE BIOREACTOR/RECIRCULATION LANDFILLS

    EPA Science Inventory

    Six bioreactor landfills were analyzed to provide a perspective of current practice and technical issues that differentiate bioreactor landfills from conventional landfills. Five of the bioreactor landfills were anaerobic and one was aerated. In one case, nearly identical cells e...

  5. Integrating remediation and resource recovery: On the economic conditions of landfill mining.

    PubMed

    Frändegård, Per; Krook, Joakim; Svensson, Niclas

    2015-08-01

    This article analyzes the economic potential of integrating material separation and resource recovery into a landfill remediation project, and discusses the result and the largest impact factors. The analysis is done using a direct costs/revenues approach and the stochastic uncertainties are handled using Monte Carlo simulation. Two remediation scenarios are applied to a hypothetical landfill. One scenario includes only remediation, while the second scenario adds resource recovery to the remediation project. Moreover, the second scenario is divided into two cases, case A and B. In case A, the landfill tax needs to be paid for re-deposited material and the landfill holder does not own a combined heat and power plant (CHP), which leads to disposal costs in the form of gate fees. In case B, the landfill tax is waived on the re-deposited material and the landfill holder owns its own CHP. Results show that the remediation project in the first scenario costs about €23/ton. Adding resource recovery as in case A worsens the result to -€36/ton, while for case B the result improves to -€14/ton. This shows the importance of landfill tax and the access to a CHP. Other important factors for the result are the material composition in the landfill, the efficiency of the separation technology used, and the price of the saleable material. PMID:25962826

  6. Influence of tropical seasonal variations on landfill leachate characteristics--results from lysimeter studies.

    PubMed

    Tränkler, J; Visvanathan, C; Kuruparan, P; Tubtimthai, O

    2005-01-01

    Considering the quality of design and construction of landfills in developing countries, little information can be derived from randomly taken leachate samples. Leachate generation and composition under monsoon conditions have been studied using lysimeters to simulate sanitary landfills and open cell settings. In this study, lysimeters were filled with domestic waste, highly organic market waste and pre-treated waste. Results over two subsequent dry and rainy seasons indicate that the open cell lysimeter simulation showed the highest leachate generation throughout the rainy season, with leachate flow in all lysimeters coming to a halt during the dry periods. More than 60% of the precipitation was found in the form of leachate. The specific COD and TKN load discharged from the open cell was 20% and 180% more than that of the sanitary landfill lysimeters. Types of waste material and kind of pre-treatment prior to landfilling strongly influenced the pollutant load. Compared to the sanitary landfill lysimeter filled with domestic waste, the specific COD and TKN load discharged from the pre-treated waste lysimeter accounted for only 4% and 16%, respectively. Considering the local settings of tropical landfills, these results suggest that landfill design and operation has to be adjusted. Leachate can be collected and stored during the rainy season, and recirculation of leachate is recommended to maintain a steady and even accelerated degradation during the prolonged dry season. The open cell approach in combination with leachate recirculation is suggested as an option for interim landfill operations. PMID:16002273

  7. Influence of the gas composition on the efficiency of ammonia stripping of biogas digestate.

    PubMed

    Bousek, J; Scroccaro, D; Sima, Jan; Weissenbacher, Norbert; Fuchs, W

    2016-03-01

    Impact of strip gas composition on side stream ammonia stripping, a technology aiming at the reduction of high ammonia levels in anaerobic reactors, was investigated. Evaluation of the effect of oxygen contact during air stripping showed a distinct, though lower than perceived, inhibition of anaerobic microflora. To circumvent, the feasibility and possible constraints of biogas and flue gas as alternatives in side stream stripping were studied. Experiments, with ammonia bicarbonate model solution and digestate, were conducted. It was demonstrated that the stripping performance is negatively correlated to the CO2 level in the strip gas with a progressive performance loss towards higher concentrations. In contrast to biogas with its high CO2 content, the efficiency reduction observed for flue gas was significantly less pronounced. The later provides the additional benefit that its high thermal energy can be re-utilized in the stripping unit and it is therefore considered a viable alternative for air. PMID:26735881

  8. Temporal changes in noble gas compositions within the Aidlinsector ofThe Geysers geothermal system

    SciTech Connect

    Dobson, Patrick; Sonnenthal, Eric; Kennedy, Mack; van Soest,Thijs; Lewicki, Jennifer

    2006-05-03

    The use of nonreactive isotopic tracers coupled to a full thermal-hydrological reservoir simulation allows for an improved method of investigating how reservoir fluids contained within matrix and fractures contribute over time to fluids produced from geothermal systems. A combined field and modeling study has been initiated to evaluate the effects of injection, production, and fracture-matrix interaction on produced noble gas contents and isotopic ratios. Gas samples collected periodically from the Aidlin steam field at The Geysers, California, between 1997 and 2006 have been analyzed for their noble gas compositions, and reveal systematic shifts in abundance and isotopic ratios over time. Because of the low concentrations of helium dissolved in the injection waters, the injectate itself has little impact on the helium isotopic composition of the reservoir fluids over time. However, the injection process may lead to fracturing of reservoir rocks and an increase in diffusion-controlled variations in noble gas compositions, related to gases derived from fluids within the rock matrix.

  9. Comparison of air dispersion modeling results with ambient air sampling data: A case study at Tacoma Landfill, a National Priorities List Site

    SciTech Connect

    Griffin, L.R. ); Rutherford, T.L. )

    1994-08-01

    Air dispersion modeling, ambient air sampling, and emissions testing of landfill sources have been performed to evaluate the effects of remedial activities on ambient air surrounding the Tacoma Landfill. In 1983, the Tacoma Landfill was placed on the National Priorities List (NPL) as part of the Commencement Bay/South Tacoma Channel Superfund site. Remedial activities completed, or near completion, at the 190 acre (768,903 m[sup 2]) Tacoma Landfill include a groundwater extraction system and air stripping units used to remove volatile organic compounds (VOCs) from groundwater, landfill gas extraction and flare system to control gas migration from the landfill, landfill liner and leachate collection system for an active section of the landfill, and a landfill cap that covers the inactive portions of the landfill. Dispersion modeling was performed with measured stack emission data using Industrial Source Complex (ISC) to determine the groundlevel concentrations of VOCs from the air stripper, flares, and active portion of the landfill for comparison with the measured ambient air data collected during 1992. 9 refs., 3 figs., 6 tabs.

  10. Subsurface investigation in Sarimukti landfill using DC resistivity

    NASA Astrophysics Data System (ADS)

    Kirana, Kartika Hajar; Susanto, Kusnahadi; Susilawati, Anggie

    2015-09-01

    Layering process in landfill will produce leachate that produced by the entry of a mixture of rain water or ground water into the piles solid waste. In Sarimukti landfill, leachate from landfill channeled through a pipe to the leachate pond that planted beneath the soil surface. If the pipe is leaking, the leachate will contaminate the surrounding soil and may also to contaminate groundwater. Therefore, it is necessary to investigate subsurface conditions. One type of subsurface investigation can be determined by measuring the resistivity by using DC resistivity method. Resistivity measured in Sarimukti landfill with semigriding design including 8 lines perpendicular to each other. The result show there is resistivity contrast of materials, such as the solid waste, soil, water content that is predicted as leachate, and methane gas. The range of resistivity values are from 1 Ωm to 500 Ωm with variations of depth in according to line lenght. The resistivity values respectively: leachate is 1 to 10 Ωm; Wet soil is 10 to 100 Ωm; wet waste is 100 to 400 Ωm; gas is > 400 Ωm. Then, leachate was found at depth of 25 meters and wet soil is predicted as aquifer layer with 70 meters depth. The resistivity of aquifer layer is 1 to 20 Ωm and covered by silt clay as clay cap. Thus, it can predicted that leachate not seep into the aquifer layer.

  11. Landfill to Learning Facility

    NASA Astrophysics Data System (ADS)

    Venner, Laura

    2008-05-01

    Engaging "K-to-Gray” audiences (children, families, and older adults) in scientific exploration and discovery is the main goal of the NJMC Center for Environmental and Scientific Education and the William D. McDowell Observatory located in Lyndhurst, NJ. Perched atop a closed and reclaimed municipal solid waste landfill, our new LEED - certified building (certification pending) and William D. McDowell observatory will bring hands-on scientific experiences to the 25,000 students and 3,000 adults that visit our site from the NY/NJ region each year. Our programs adhere to the New Jersey Core Curriculum Content Standards and are modified for accessibility for the underserved communities that visit us, specifically those individuals that have mobility, sensory, and/or cognitive ability differences. The programs are conducted in a classroom setting and are designed to nourish the individual's inquisitive nature and provide an opportunity to function as a scientist by, making observations, performing experiments and recording data. We have an $850,000, three year NSF grant that targets adults with disabilities and older adults with age related limitations in vision, hearing, cognition and/or mobility. From dip netting in the marsh to astronomical investigation of the cosmos, the MEC/CESE remains committed to reaching the largest audience possible and leaving them with a truly exceptional scientific experience that serves to educate and inspire.

  12. Decomposition of forest products buried in landfills.

    PubMed

    Wang, Xiaoming; Padgett, Jennifer M; Powell, John S; Barlaz, Morton A

    2013-11-01

    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 2.5yr. 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 0.27gOCg(-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 previously reported. PMID:23942265

  13. Town of Edinburg landfill reclamation demonstration project

    SciTech Connect

    Not Available

    1992-05-15

    Landfill reclamation is the process of excavating a solid waste landfill to recover materials, reduce environmental impacts, restore the land resource, and, in some cases, extend landfill life. Using conventional surface mining techniques and specialized separation equipment, a landfill may be separated into recyclable material, combustible material, a soil/compost fraction and residual waste. A landfill reclamation demonstration project was hosted at the Town of Edinburg municipal landfill in northwest Saratoga County. The report examines various separation techniques employed at the site and appropriate uses for reclaimed materials. Specifications regarding engineered work plans, health and safety monitoring, and contingency preparedness are discussed. Major potential applications and benefits of using landfill reclamation technology at existing landfills are identified and discussed. The research and development aspect of the report also examines optimal screening technologies, site selection protocol and the results of a test burn of reclaimed waste at a waste-to-energy facility. Landfill reclamation costs are developed, and economic comparisons are made between reclamation costs and conventional landfill closure costs, with key criteria identified. The results indicate that, although dependent on site-specific conditions and economic factors, landfill reclamation can be a technically and economically feasible alternative or companion to conventional landfill closure under a range of favorable conditions. Feasibility can be determined only after an investigation of the variety of landfill conditions and reclamation options.

  14. Effects of Temperature and Gas Composition on Reduction and Swelling of Magnetite Concentrates

    NASA Astrophysics Data System (ADS)

    Kapelyushin, Yury; Sasaki, Yasushi; Zhang, Jianqiang; Jeong, Sunkwang; Ostrovski, Oleg

    2016-08-01

    The gaseous reduction of magnetite ore concentrates was studied using CO-CO2 and CO-CO2-H2 gas mixtures at different temperatures and gas compositions. The reduction of magnetite ore by CO-CO2 gas mixture was examined at temperatures 973 K to 1173 K (700 °C to 900 °C) at CO/CO2 ratio 80/20, and at varied CO/CO2 ratio from 60/40 to 85/15 at 1023 K (750 °C). In the reduction of magnetite ore by CO-CO2-H2 gas mixture, temperature was 1173 K (800 °C) and hydrogen content changed from 5 to 25 vol pct at constant CO/CO2 ratio of 80/20. Reduction of magnetite ore did not go to completion in both CO-CO2 and CO-CO2-H2 gas mixtures. Addition of H2 to the CO-CO2 gas mixture accelerated the reduction in the first 10 to 30 minutes of reaction. However, the degree of reduction by gas containing 5 to 25 vol pct H2 after 60 to 120 minutes of reaction was in the range 60 to 65 pct, while the degree of reduction by CO-CO2 gas (80 vol pct CO) after 120 minutes of reaction was close to 70 pct. Significant swelling of magnetite ore pellets was observed in the reduction by CO-CO2 gas mixture. Addition of H2 to the CO-CO2 gas mixture decreased swelling. Swelling of magnetite ore during the reduction was attributed to the breakout of iron layer caused by the increase of the inner pressure in the voids at the wüstite/iron phase boundary.

  15. Life-cycle inventory and impact evaluation of mining municipal solid waste landfills.

    PubMed

    Jain, Pradeep; Powell, Jon T; Smith, Justin L; Townsend, Timothy G; Tolaymat, Thabet

    2014-01-01

    Recent research and policy directives have emerged with a focus on sustainable management of waste materials, and the mining of old landfills represents an opportunity to meet sustainability goals by reducing the release of liquid- and gas-phase contaminants into the environment, recovering land for more productive use, and recovering energy from the landfilled materials. The emissions associated with the landfill mining process (waste excavation, screening, and on-site transportation) were inventoried on the basis of diesel fuel consumption data from two full-scale mining projects (1.3-1.5 L/in-place m(3) of landfill space mined) and unit emissions (mass per liter of diesel consumption) from heavy equipment typically deployed for mining landfills. An analytical framework was developed and used in an assessment of the life-cycle environmental impacts of a few end-use management options for materials deposited and mined from an unlined landfill. The results showed that substantial greenhouse gas emission reductions can be realized in both the waste relocation and materials and energy recovery scenarios compared to a "do nothing" case. The recovery of metal components from landfilled waste was found to have the greatest benefit across nearly all impact categories evaluated, while emissions associated with heavy equipment to mine the waste itself were found to be negligible compared to the benefits that mining provided. PMID:24512420

  16. Potential application of biocover soils to landfills for mitigating toluene emission.

    PubMed

    Su, Yao; Pei, Junshen; Tian, Baohu; Fan, Fengxi; Tang, Mengling; Li, Wei; He, Ruo

    2015-12-15

    Biocover soils have been demonstrated to be a good alternative cover material to mitigate CH4 emission from landfills. To evaluate the potential of biocover soil in mitigating emissions of non-methane volatile organic compounds (NMVOCs) from landfills, simulated cover soil columns with the influx of toluene (chosen as typical of NMVOCs) concentrations of 102-1336 mg m(-3) in the presence or absence of the major landfill gas components (i.e., CH4 and CO2) were conducted in this study. In the two experimental materials (waste biocover soils (WBS) and landfill cover soils (LCS)), higher toluene reduction was observed in WBS with respect to LCS. After the introduction of landfill gas, an increase of microbial diversity and relative abundance of toluene-degrading bacteria and methanotrophs occurred in WBS. To illustrate the role of toluene-degrading activity in mitigating toluene emissions through landfill covers, an analytical model was developed by incorporating the steady-state vapor transport with the first-order kinetics of aerobic biodegradation limited by O2 availability. This study demonstrated that biocover soils have great potential in applying to landfills for mitigating toluene emission to the atmosphere. PMID:26073517

  17. Characterization of uncertainty in estimation of methane collection from select U.S. landfills.

    PubMed

    Wang, Xiaoming; Nagpure, Ajay S; DeCarolis, Joseph F; Barlaz, Morton A

    2015-02-01

    Methane is a potent greenhouse gas generated from the anaerobic decomposition of waste in landfills. If captured, methane can be beneficially used to generate electricity. To inventory emissions and assist the landfill industry with energy recovery projects, the U.S. EPA developed the Landfill Gas Emissions Model (LandGEM) that includes two key parameters: the first-order decay rate (k) and methane production potential (L0). By using data from 11 U.S. landfills, Monte Carlo simulations were performed to quantify the effect of uncertainty in gas collection efficiency and municipal solid waste fraction on optimal k values and collectable methane. A dual-phase model and associated parameters were also developed to evaluate its performance relative to a single-phase model (SPM) similar to LandGEM. The SPM is shown to give lower error in estimating methane collection, with site-specific best-fit k values. Most of the optimal k values are notably greater than the U.S. EPA's default of 0.04 yr(-1), which implies that the gas generation decreases more rapidly than predicted at the current default. We translated the uncertainty in collectable methane into uncertainty in engine requirements and potential economic losses to demonstrate the practical significance to landfill operators. The results indicate that landfill operators could overpay for engine capacity by $30,000-780,000 based on overestimates of collectable methane. PMID:25604252

  18. Effects of flue gas compositions on nitrosamine and nitramine formation in postcombustion CO2 capture systems.

    PubMed

    Dai, Ning; Mitch, William A

    2014-07-01

    Amine-based technologies are emerging as the prime contender for postcombustion CO2 capture. However, concerns have arisen over the health impacts of amine-based CO2 capture associated with the release of nitrosamines and nitramines, which are byproducts from the reactions between flue gas NOx and solvent amines. In this study, flue gas compositions were systematically varied to evaluate their effects on the formation of nitrosamines and nitramines in a lab-scale CO2 capture reactor with morpholine as a model solvent amine. The accumulation of N-nitrosomorpholine in both the absorber and washwater increased linearly with both NO and NO2 for concentrations up to ∼20 ppmv. These correlations could be extrapolated to estimate N-nitrosomorpholine accumulation at extremely low NOx levels (0.3 ppmv NO2 and 1.5 ppmv NO). NO played a particularly important role in driving N-nitrosomorpholine formation in the washwater, likely following partial oxidation to NO2 by O2. The accumulation of N-nitromorpholine in both the absorber and washwater positively correlated with flue gas NO2 concentration, but not with NO concentration. Both N-nitrosomorpholine and N-nitromorpholine accumulated fastest in the absence of CO2. Flue gas humidity did not affect nitrosamine accumulation in either the absorber or the washwater unit. These results provide a basis for estimating the effects of flue gas composition on nitrosamine and nitramine accumulation in postcombustion CO2 capture systems. PMID:24918477

  19. Feasibility of SiC composite structures for 1644 deg gas turbine seal applications

    NASA Technical Reports Server (NTRS)

    Darolia, R.

    1979-01-01

    The feasibility of silicon carbide composite structures was evaluated for 1644 K gas turbine seal applications. The silicon carbide composites evaluated consisted of Si/SiC Silcomp (Trademark) - and sintered silicon carbide as substrates, both with attached surface layers containing BN as an additive. A total of twenty-eight candidates with variations in substrate type and density, and layer chemistry, density, microstructure, and thickness were evaluated for abradability, cold particle erosion resistance, static oxidation resistance, ballistic impact resistance, and fabricability. The BN-free layers with variations in density and pore size were later added for evaluation. The most promising candidates were evaluated for Mach 1.0 gas oxidation/erosion resistance from 1477 K to 1644 K. The as-fabricated rub layers did not perform satisfactorily in the gas oxidation/erosion tests. However, preoxidation was found to be beneficial in improving the hot gas erosion resistance. Overall, the laboratory and rig test evaluations show that material properties are suitable for 1477 K gas turbine seal applications.

  20. Supercritical water oxidation of landfill leachate

    SciTech Connect

    Wang Shuzhong; Guo Yang; Chen Chongming; Zhang Jie; Gong Yanmeng; Wang Yuzhen

    2011-09-15

    Highlights: > Thermal analysis of NH{sub 3} in supercritical water oxidation reaction. > Research on the catalytic reaction of landfill leachate by using response surface method. > Kinetic research of supercritical water oxidation of NH{sub 3} with and without MnO{sub 2} catalyst. - Abstract: In this paper, ammonia as an important ingredient in landfill leachate was mainly studied. Based on Peng-Robinson formulations and Gibbs free energy minimization method, the estimation of equilibrium composition and thermodynamic analysis for supercritical water oxidation of ammonia (SCWO) was made. As equilibrium is reached, ammonia could be totally oxidized in SCW. N{sub 2} is the main product, and the formation of NO{sub 2} and NO could be neglected. The investigation on SCWO of landfill leachate was conducted in a batch reactor at temperature of 380-500 deg. C, reaction time of 50-300 s and pressure of 25 MPa. The effect of reaction parameters such as oxidant equivalent ratio, reaction time and temperature were investigated. The results showed that COD and NH{sub 3} conversion improved as temperature, reaction time and oxygen excess increased. Compared to organics, NH{sub 3} is a refractory compound in supercritical water. The conversion of COD and NH{sub 3} were higher in the presence of MnO{sub 2} than that without catalyst. The interaction between reaction temperature and time was analyzed by using response surface method (RSM) and the results showed that its influence on the NH{sub 3} conversion was relatively insignificant in the case without catalyst. A global power-law rate expression was regressed from experimental data to estimate the reaction rate of NH{sub 3}. The activation energy with and without catalyst for NH{sub 3} oxidation were 107.07 {+-} 8.57 kJ/mol and 83.22 {+-} 15.62 kJ/mol, respectively.

  1. Field water balance of landfill final covers.

    PubMed

    Albright, William H; Benson, Craig H; Gee, Glendon W; Roesler, Arthur C; Abichou, Tarek; Apiwantragoon, Preecha; Lyles, Bradley F; Rock, Steven A

    2004-01-01

    Landfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side-by-side testing. A study was conducted to assess the ability of landfill final covers to control percolation into underlying waste. Conventional covers employing resistive barriers as well as alternative covers relying on water-storage principles were monitored in large (10 x 20 m), instrumented drainage lysimeters over a range of climates at 11 field sites in the United States. Surface runoff was a small fraction of the water balance (0-10%, 4% on average) and was nearly insensitive to the cover slope, cover design, or climate. Lateral drainage from internal drainage layers was also a small fraction of the water balance (0-5.0%, 2.0% on average). Average percolation rates for the conventional covers with composite barriers (geomembrane over fine soil) typically were less than 12 mm/yr (1.4% of precipitation) at humid locations and 1.5 mm/yr (0.4% of precipitation) at arid, semiarid, and subhumid locations. Average percolation rates for conventional covers with soil barriers in humid climates were between 52 and 195 mm/yr (6-17% of precipitation), probably due to preferential flow through defects in the soil barrier. Average percolation rates for alternative covers ranged between 33 and 160 mm/yr (6 and 18% of precipitation) in humid climates and generally less than 2.2 mm/yr (0.4% of precipitation) in arid, semiarid, and subhumid climates. One-half (five) of the alternative covers in arid, semiarid, and subhumid climates transmitted less than 0.1 mm of percolation, but two transmitted much more percolation (26.8 and 52 mm) than anticipated during design. The data collected support conclusions from other studies that detailed, site-specific design procedures are very important for successful performance of alternative landfill covers. PMID:15537955

  2. Composite wrap approved for U.S. gas-pipeline repairs

    SciTech Connect

    True, W.R.

    1995-10-09

    The US agency that oversees pipeline safety has taken the unusual step of waiving certain natural-gas pipeline maintenance regulations and permitted a group of gas-pipeline operators to perform repairs with a patented composite wrap formerly used only on liquids lines. The waivers ar subject to conditions and to future performance evaluations. The wrap is made of polyester resin reinforced by glass filament. On installation, it is tightly wound and adhesively bonded to damaged pipe. The paper describes the 2 waivers, the development of this new technology, savings, and training required by the Dept. of Transportation.

  3. Development of New-type Outdoor Termination using Composite Insulator with SF6 Gas

    NASA Astrophysics Data System (ADS)

    Kusuda, Yusuke; Fukuda, Kinya; Matsumura, Masao; Hagisawa, Kazuhisa; Okamoto, Gaku; Nakanishi, Tatsuo; Inoue, Yoshiyuki

    Recently, composite insulators have been increasingly employed mainly from the economic viewpoint. We have been developed new type outdoor termination with composite insulator, which can be installed horizontally on the steel tower, in order to reduce the construction cost. In this outdoor termination, SF6 gas is filled in the composite insulator and a cold shrinkable pre-molded rubber unit is applied instead of the combinational use of rubber-molded stress relief cone, epoxy resin insulator and spring unit. The application of composite insulator, SF6 gas and cold shrinkable pre-molded rubber unit lights the total weight and makes it possible to install horizontally on the tower. The composite insulator type outdoor termination for 77kV XLPE cable has already applied as commercial use and enabled to reduce the construction cost of power transmission lines. A 154kV new type outdoor termination has been developed and successfully completed the initial electrical test. This paper describes the design and performance of both 77kV and 154kV new type outdoor termination, and the follow-up survey of 77kV outdoor termination in the commercial power transmission line.

  4. Method of making a continuous ceramic fiber composite hot gas filter

    DOEpatents

    Hill, Charles A.; Wagner, Richard A.; Komoroski, Ronald G.; Gunter, Greg A.; Barringer, Eric A.; Goettler, Richard W.

    1999-01-01

    A ceramic fiber composite structure particularly suitable for use as a hot gas cleanup ceramic fiber composite filter and method of making same from ceramic composite material has a structure which provides for increased strength and toughness in high temperature environments. The ceramic fiber composite structure or filter is made by a process in which a continuous ceramic fiber is intimately surrounded by discontinuous chopped ceramic fibers during manufacture to produce a ceramic fiber composite preform which is then bonded using various ceramic binders. The ceramic fiber composite preform is then fired to create a bond phase at the fiber contact points. Parameters such as fiber tension, spacing, and the relative proportions of the continuous ceramic fiber and chopped ceramic fibers can be varied as the continuous ceramic fiber and chopped ceramic fiber are simultaneously formed on the porous vacuum mandrel to obtain a desired distribution of the continuous ceramic fiber and the chopped ceramic fiber in the ceramic fiber composite structure or filter.

  5. Composite fan exit guide vanes for high bypass ratio gas turbine engines

    NASA Technical Reports Server (NTRS)

    Blecherman, S. S.; Stankunas, T. N.

    1981-01-01

    Various composite materials were identified for reduced weight applications as fan exit guide vanes in high bypass ratio gas turbine engines. Candidate materials, airfoil geometry and ply orientation were evaluated using NASTRAN finite element analysis. A vane core and shell design approach utilizing several different fiber orientation concepts was selected and variations in bending and torsional stiffness were documented. Material suppliers and airfoil fabricators were selected to provide panels and airfoils which were inspected, environmentally conditioned and tested. Static and dynamic airfoil tests established durability characteristics for a range of composite material/design approaches.

  6. Impact of changes in barometric pressure on landfill methane emission

    NASA Astrophysics Data System (ADS)

    Xu, Liukang; Lin, Xiaomao; Amen, Jim; Welding, Karla; McDermitt, Dayle

    2014-07-01

    Landfill methane emissions were measured continuously using the eddy covariance method from June to December 2010. The study site was located at the Bluff Road Landfill in Lincoln, Nebraska, USA. Our results show that landfill methane emissions strongly depended on changes in barometric pressure; rising barometric pressure suppressed the emission, while falling barometric pressure enhanced the emission, a phenomenon called barometric pumping. There was up to a 35-fold variation in day-to-day methane emissions due to changes in barometric pressure. Wavelet coherence analysis revealed a strong spectral coherency between variations of barometric pressure and methane emission at periodicities ranging from 1 day to 8 days. Power spectrum and ogive analysis showed that at least 10 days of continuous measurements was needed in order to capture 90% of the total variance in the methane emission time series at our landfill site. From our results, it is clear that point-in-time measurements taken at monthly or longer time intervals using techniques such as the trace plume method, the mass balance method, or the closed-chamber method will be subject to large variations in measured emission rates because of the barometric pumping phenomenon. Estimates of long-term integrated methane emissions from landfills based on such measurements could yield uncertainties, ranging from 28.8% underestimation to 32.3% overestimation. Our results demonstrate a need for continuous measurements to quantify annual total landfill emissions. This conclusion may apply to the study of methane emissions from wetlands, peatlands, lakes, and other environmental contexts where emissions are from porous media or ebullition. Other implications from the present study for hazard gas monitoring programs are also discussed.

  7. Landfill mining for resource recovery

    SciTech Connect

    Reith, C.C.