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1

Temporal variability of soil gas composition in landfill covers.  

PubMed

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

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

2011-05-01

2

Municipal Landfill Gas Condensate,  

National Technical Information Service (NTIS)

New regulations relative to air emissions from municipal landfills may require the installation of gas collection systems at landfills. As landfill gas (LFG) is collected, water and other vapors in the gas condense in the system or are purposely removed i...

J. Briggs

1987-01-01

3

Trace gas measurements in landfill gas from closed landfill sites  

Microsoft Academic Search

Five closed landfill sites in the urban area of Wolverhampton, UK were investigated in order to identify the trace components in landfill gas emitted from each site. 17 different compounds were identified in the gas samples following analysis by gas chromatography?mass spectrometry.It appeared that concentrations of carbon disulphide, xylene and toluene detected at the landfill sites were related to site

P. Giess; A. Bush; M. Dye

1999-01-01

4

Landfill Gas Production from Large Landfill Simulators.  

National Technical Information Service (NTIS)

Two sizes of landfill simulators or test cells; one set containing approximately 320 kg wet weight of municipal solid wastes (MSW) and the other set containing 2555 kg wet weight of MSW were used to measure the amount and composition of gases produced fro...

L. W. Jones R. J. Larson P. G. Malone

1984-01-01

5

LANDFILL GAS PRODUCTION FROM LARGE LANDFILL SIMULATORS  

EPA Science Inventory

Two sizes of landfill simulators or test cells; one set containing approximately 320 kg wet weight of municipal solid wastes (MSW) and the other set containing 2555 kg wet weight of MSW were used to measure the amount and composition of gases produced from MSW under typical landf...

6

Sour landfill gas problem solved  

Microsoft Academic Search

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.

G. Nagl; R. Cantrall

1996-01-01

7

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

PubMed

At a municipal solid waste landfill in southern California (USA) overlying a natural gas reservoir, methane was detected at concentrations of up to 40% (by volume) in perimeter soil gas probes. Stable isotope and (14)C values of methane together with gas composition (major components and volatile organic compounds) data were evaluated to assess the relative contributions of landfill gas and natural gas to the measured methane concentrations. The data was further used to estimate the residence time of the landfill gas in the probes. Results showed that up to 37% of the measured methane was derived from landfill gas. In addition, the landfill gas in the probe samples has undergone extensive alteration due to dissolution of carbon dioxide in pore water. Data further indicates that the measured methane was released from the waste approximately 1.2 to 9.4 years ago, rather than representing evidence of an ongoing release. PMID:23660592

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

2013-06-01

8

Sour landfill gas problem solved  

SciTech Connect

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.

Nagl, G.; Cantrall, R. [Wheelabrator Clean Air Systems, Inc., Schaumburg, IL (United States)

1996-05-01

9

Migrating landfill gas proves challenging  

Microsoft Academic Search

Located in the San Fernando Valley at the foothills of the San Gabriel mountains, the 41-acre Sheldon-Arleta Landfill originated as one of many gravel pits in the area and was operated by CalMat as a gravel quarry pit from the mid 1950s until 1962. In 1967, methane gas was detected in the residential dwellings located across from the landfill along

J. G. Dobrowolski; A. S. Dellinger

1994-01-01

10

Modeling landfill gas production and movement: Principal landfill gases  

Microsoft Academic Search

A landfill gas generation and movement model is presented in this dissertation. The model is based on solution of a Darcy's law formulation of single component fluid flow in porous media in three dimensions, using a finite element technique. The effects of varying gas production rates, material porosities, and landfill covers, liners, and gas extraction wells are incorporated in the

1991-01-01

11

Characterization of malodorous sulfur compounds in landfill gas  

Microsoft Academic Search

In order to analyze the composition of landfill gas (LFG) with respect to malodorous components, the concentrations of several reduced sulfur compounds (RSC: hydrogen sulfide (H2S); methyl mercaptan (CH3SH); dimethyl sulfide ((CH3)2S); carbon disulfide (CS2); and dimethyl disulfide ((CH3)2S2)) were determined from four municipal landfill sites—initialed W, B, H, and N—in Korea. The S gas concentrations measured in these landfill

Ki-Hyun Kim; YJ Choi; EC Jeon; Young Sunwoo

2005-01-01

12

Turning landfill gas into kilowatts  

Microsoft Academic Search

This paper reports that in West Berlin, German waste officials decided to handle their landfill gas problem by building a cogeneration facility to harness the gas energy. The Berlin-Wannsee municipal waste disposal site was opened in 1954 and closed in 1980. The former gravel pit was 33 feet deep and covered 600,000 square yards. It was refilled with 11 million

Feit

1991-01-01

13

Gas movement through fractured landfill cover materials  

Microsoft Academic Search

Bidirectional gas movement through fractured landfill cover materials is being studied at the Mallard North Landfill in DuPage County, Illinois. Vertical pressure and concentration gradients were monitored during changing meteorological and soil moisture conditions. Nests of probes for direct observation of subsurface soil gas pressures were installed in the top of the refuse and at depths of 1.2 m and

J. E. Bogner; C. A. Moore

1986-01-01

14

Bioenergy from landfill gas (LFG) in Taiwan  

Microsoft Academic Search

Greenhouse gases (GHGs) emissions are becoming significant energy and environmental issues relating to municipal solid waste (MSW) deposited in landfills in Taiwan. The nation, although not a Party to the Montreal Protocol and Kyoto Protocol, has diligently striven to mitigate and phase out them. The landfill gas (LFG), which is now considered as a renewable energy with emphasis on electricity

W. T. Tsai

2007-01-01

15

Composition and source identification of deposits forming in landfill gas (LFG) engines and effect of activated carbon treatment on deposit composition.  

PubMed

Compositions of deposits forming on engines parts operated with landfill gas (LFG) were analyzed. The deposit compositions were compared before and after the installation of activated carbon system for treatment of LFG. Deposits forming on the spark plugs had significantly higher levels of calcium, chromium, and nickel in comparison to those forming on the engine heads. The LFG contained about 9.5 ± 0.4 mg/m(3) total siloxanes, majority of which were octamethylcyclotetrasiloxane (D4) (5.0 ± 0.2 mg/m(3)), decamethylcyclopentasiloxane (D5) (2.9 ± 0.1 mg/m(3)) and hexamethyldisiloxane (L2) (1.6 ± 0.1 mg/m(3)). The samples collected from the engine heads before the activated carbon treatment of LFG had significantly high levels of silicon (149,400 ± 89,900 mg/kg) as well as calcium (70,840 ± 17,750 mg/kg), sulfur (42,500 ± 11,500 mg/kg), and zinc (22,300 ± 7200 mg/kg). After the activated carbon treatment, silicon levels decreased significantly; however, deposits had higher sulfur content (104,560 ± 68,100 mg/kg) indicating that the activated carbon released some sulfur during treatment. The analyses indicate that zinc and calcium originated from the additives in the lube oil while lead, aluminum, copper, nickel, iron, chromium were due to the engine wear. PMID:23770437

Sevimo?lu, Orhan; Tansel, Berrin

2013-10-15

16

Proceedings from the GRCDA 9th international landfill gas symposium  

SciTech Connect

This book presents the papers given at a conference on methane recovery from sanitary landfills. Topics considered at the conference included hazardous wastes, gaseous wastes, emission, pollution regulations, landfill testing, ambient air monitoring, landfill gas control, methane collection system operation and maintenance, estimating landfill gas yields, the production of high BTU gas, medium BTU gas, the pressure swing MDEA process, landfill gas power conversion, and methane fuel cells.

Not Available

1986-01-01

17

How landfill gas causes RCRA compliance problems  

SciTech Connect

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.

Kerfoot, H.B. [Kerfoot and Associates, Las Vegas, NV (United States)

1996-06-01

18

Effects of landfill gas on subtropical woody plants  

NASA Astrophysics Data System (ADS)

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

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

1991-05-01

19

Landfill Gas Generation and Migration: Review of Current Research.  

National Technical Information Service (NTIS)

With regard to gas migration, a field investigation is examining bidirectional gas movement through landfill cover materials by processes of pressure and diffusional flow. The purpose of the study is to quantify gas loss from the landfill reservoir by nat...

J. Bogner C. Rose M. Vogt D. Gartman

1987-01-01

20

Using landfill gas for energy: Projects that pay  

SciTech Connect

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.

NONE

1995-02-01

21

Partitioning Gas Tracer Technology for Measuring Water in Landfills  

NASA Astrophysics Data System (ADS)

Unstable landfills can result in significant environmental contamination and can become a risk to public health. To reduce this risk, water may be added to landfills to ensure that enough moisture exists for biodegradation of organic wastes. In this case risks associated with future breaks in the landfill cap are significantly reduced because organic material is degraded more rapidly. To modify moisture conditions and enhance biodegradation, leachate is typically collected from the bottom of the landfill and then recirculated near the top. It is difficult, though, to know how much leachate to add and where to add it to achieve uniform moisture conditions. This situation is exacerbated by the heterogeneous nature of landfill materials, which is known to cause short circuiting of infiltrating water, a process that has been virtually impossible to measure or model. Accurate methods for measuring the amount of water in landfills would be valuable aids for implementing leachate recirculation systems. Current methods for measuring water are inadequate, though, since they provide point measurements and are frequently affected by heterogeneity of the solid waste composition and solid waste compaction. The value of point measurements is significantly reduced in systems where water flows preferentially, such as in landfills. Here, spatially integrated measurements might be of greater value. In this research we are evaluating a promising technology, the partitioning gas tracer test, to measure the water saturation within landfills, the amount of free water in solid waste divided by the volume of the voids. The partitioning gas tracer test was recently developed by researchers working in the vadose zone. In this methodology two gas tracers are injected into a landfill. One tracer is non-reactive with landfill materials, while the second partitions into and out of free water trapped within the pore space of the solid waste. Chromatographic separation of the tracers occurs between the point of tracer injection and tracer extraction because the partitioning tracer is retarded due to water in the landfill. The degree of tracer retardation can be used to determine the average water saturation between the injection and extraction points. This partitioning gas tracer test yields a large-scale estimate of the water saturation, is not affected by solid waste compaction or heterogeneity in the composition of the solid waste, and has been successfully tested in a recent field experiment in soils. We report the results from a series of laboratory experiments designed to evaluate this technology with various trash mixtures. Experimental conditions were selected to mimic the range of moisture conditions that may exist within municipal landfills. The influence of leachate composition and temperature on gas tracer partitioning were also evaluated. In our trash mixtures, the partitioning gas tracer test determined volumetric water contents that were within 12% of actual values. We discuss these data in detail and describe environmental conditions (e.g., temperature variations) that may affect the utility of the partitioning gas tracer test.

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

2002-12-01

22

Understanding natural and induced gas migration through landfill cover materials: the basis for improved landfill gas recovery  

Microsoft Academic Search

Vertical pressure and concentration gradients in landfill cover materials are being examined at the Mallard North Landfill in Dupage County, IL. The goal of this project is to understand venting of landfill gas and intrusion of atmospheric gases into the landfill in response to changing meteorological conditions (particularly barometric pressure and precipitation) and pumping rates at recovery wells. Nests of

Bogner

1986-01-01

23

LANDFILL GAS RECOVERY/UTILIZATION - OPTIONS AND ECONOMICS  

EPA Science Inventory

The paper describes the options and economics for landfill gas utilization. (NOTE: The decomposition of landfilled waste results in a gas that can be either a source of pollution or a resource. f the more than 6000 active municipal solid waste landfills in the U. S., there are 11...

24

Funding Landfill Gas Projects. A Guide to State, Federal, and Foundation Resources.  

National Technical Information Service (NTIS)

More than 340 communities, landfill owners and operators, and state officials across the U.S. are learning that landfill gas is an important local and regional resource. To develop landfill gas utilization projects, landfill owners and operators capture l...

2004-01-01

25

Landfill gas control at military installations. Final report  

Microsoft Academic Search

This report provides information useful to Army personnel responsible for recognizing and solving potential problems from gas generated by landfills. Information is provided on recognizing and gauging the magnitude of landfill gas problems; selecting appropriate gas control strategies, procedures, and equipment; use of computer modeling to predict gas production and migration and the success of gas control devices; and safety

R. A. Shafer; A. Renta-Babb; J. T. Bandy; E. D. Smith; P. Malone

1984-01-01

26

Utilization of Landfill Gas for a Vehicle Fuel System: Rossman's Landfill, Clackamas County, Oregon. Feasibility Study.  

National Technical Information Service (NTIS)

The areas addressed in this feasibility study include: landfill gas yield and collection, including an estimate of production rates, a prediction of methane yield versus time, and development of a conceptual gas-gathering system; gas processing, compressi...

1983-01-01

27

Gas movement through fractured landfill cover materials  

SciTech Connect

Bidirectional gas movement through fractured landfill cover materials is being studied at the Mallard North Landfill in DuPage County, Illinois. Vertical pressure and concentration gradients were monitored during changing meteorological and soil moisture conditions. Nests of probes for direct observation of subsurface soil gas pressures were installed in the top of the refuse and at depths of 1.2 m and 0.6 m. Subsurface gas pressures, barometric pressure, wind speed, wind direction, solar radiation, air temperature, and precipitation were continuously monitored. A field gas chromatograph permitted frequent analysis of methane, carbon dioxide, nitrogen, and oxygen in soil gas samples from the various probes. Tensiometers provided information on soil moisture conditions. During dry weather, soil gas pressures at all depths equilibrated rapidly with barometric pressure and exhibited diurnal variations that were inversely proportional to diurnal temperature variations. When cover materials became saturated, changes in soil gas pressures sometimes lagged behind changes in atmospheric pressure by two to three hours. Soil gas concentrations generally exhibited relatively small short-term variations, but responded over the longer term to changing soil moisture conditions. Carbon-dioxide:methane ratios suggest that an important near-surface process is the activity of methane-oxidizing bacteria, which consume methane that might otherwise be available to a gas recovery system.

Bogner, J.E.; Moore, C.A.

1986-01-01

28

An energy perspective on landfill gas  

SciTech Connect

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.

Hutchinson, P.J. (Hutchinson Group, Ltd., Murrysville, PA (United States))

1993-01-01

29

Quantifying Uncontrolled Landfill Gas Emissions from Two Florida Landfills.  

National Technical Information Service (NTIS)

The purpose of this study is to evaluate fugitive loss from two different municipal landfills which were reported to be operating as a wet or bioreactor landfill and have an area regarded as a control cell (where no additional liquid was added). Fugitive ...

2009-01-01

30

Landfill gas pretreatment for fuel cell applications  

NASA Astrophysics Data System (ADS)

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.

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

1994-04-01

31

Microbial mitigation of greenhouse gas emissions from landfill cover soils  

Microsoft Academic Search

Landfills are one of the major sources of methane (CH4), a potent greenhouse gas with a global warming potential (GWP) ˜23 times higher than that of carbon dioxide (CO2). Although some effective strategies have been formulated to prevent methane emissions from large landfills, many landfills allow methane to be freely emitted to the atmosphere. In such situations, it is often

Sung-Woo Lee

2008-01-01

32

Landfill gas generation and migration: Review of current research  

Microsoft Academic Search

With regard to gas migration, a field investigation is examining bidirectional gas movement through landfill cover materials by processes of pressure and diffusional flow. The purpose of the study is to quantify gas loss from the landfill reservoir by natural venting and air influx due to pumping on recovery wells. Two field sites - a humid site with clay cover

J. Bogner; C. Rose; M. Vogt; D. Gartman

1987-01-01

33

Gas production and migration in landfills and geological materials  

NASA Astrophysics Data System (ADS)

Landfill gas, originating from the anaerobic biodegradation of the organic content of waste, consists mainly of methane and carbon dioxide, with traces of volatile organic compounds. Pressure, concentration and temperature gradients that develop within the landfill result in gas emissions to the atmosphere and in lateral migration through the surrounding soils. Environmental and safety issues associated with the landfill gas require control of off-site gas migration. The numerical model TOUGH2-LGM (Transport of Unsaturated Groundwater and Heat-Landfill Gas Migration) has been developed to simulate landfill gas production and migration processes within and beyond landfill boundaries. The model is derived from the general non-isothermal multiphase flow simulator TOUGH2, to which a new equation of state module is added. It simulates the migration of five components in partially saturated media: four fluid components (water, atmospheric air, methane and carbon dioxide) and one energy component (heat). The four fluid components are present in both the gas and liquid phases. The model incorporates gas-liquid partitioning of all fluid components by means of dissolution and volatilization. In addition to advection in the gas and liquid phase, multi-component diffusion is simulated in the gas phase. The landfill gas production rate is proportional to the organic substrate and is modeled as an exponentially decreasing function of time. The model is applied to the Montreal's CESM landfill site, which is located in a former limestone rock quarry. Existing data were used to characterize hydraulic properties of the waste and the limestone. Gas recovery data at the site were used to define the gas production model. Simulations in one and two dimensions are presented to investigate gas production and migration in the landfill, and in the surrounding limestone. The effects of a gas recovery well and landfill cover on gas migration are also discussed.

Nastev, Miroslav; Therrien, René; Lefebvre, René; Gélinas, Pierre

2001-11-01

34

Case study: City of Industry landfill gas recovery operation  

SciTech Connect

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)

None

1981-11-01

35

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

NASA Astrophysics Data System (ADS)

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

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

36

Landfill gas management: View from Italy.  

National Technical Information Service (NTIS)

Landfilling is the most widely used waste disposal system in Italy. More than 85% of the total refuse produced is landfilled, as the other ways still have many problems. People do not easily accept landfilling, and many regions of the country have very di...

F. De Poli S. Pasqualini

1993-01-01

37

Evaluation of Partitioning Gas Tracer Tests for Measuring Water in Landfills  

NASA Astrophysics Data System (ADS)

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 which a vacuum was applied. The results from this test are reported along with an overview of a similar test planned for the bioreactor landfill cells operated by the Yolo County Department of Planning and Public Works.

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

38

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

SciTech Connect

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.

NONE

1997-06-01

39

Control Techniques for Gas Emissions from Hazardous Waste Landfills  

Microsoft Academic Search

While land disposal of hazardous wastes is being used widely as a practical and economically attractive disposal method, significant damage to the economy, environment, and public health have resulted from inadequate land disposal procedures. The air pollution aspects related to hazardous waste landfills are discussed. Topics addressed include landfill gas generation, problem identification, and control techniques. Three basic ways to

Thomas T. Shen

1981-01-01

40

Removal and determination of trimethylsilanol from the landfill gas  

Microsoft Academic Search

The removal and determination of trimethylsilanol (TMSOH) in landfill gas has been studied before and after the special E3000-ITC System. The system works according to principle of temperature swing. The performance of TMSOH and humidity removal was 20% and more than 90%, respectively. The six of active carbons and impinger method were tested on the full-scale landfill in Poland for

Grzegorz Piechota; Manfred Hagmann; Roman Buczkowski

41

Landfill Gas Utilization: Database of North American Projects.  

National Technical Information Service (NTIS)

Data landfill-gas (LFG)-to-energy projects have been reported for U.S. landfills and to a lesser extent on Canadian projects. The paper describes the LFG-to-energy industry, providing data on the types of projects in North America, the current energy outp...

S. A. Thorneloe J. G. Pacey

1994-01-01

42

Keeping landfill gas systems in tune  

SciTech Connect

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.

Blackman, L.; Myers, L.; Bjerkin, L.; Freemon, P. [County Sanitation Districts of Los Angeles County, Whittier, CA (United States)

1998-01-01

43

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

SciTech Connect

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)

None

1981-01-01

44

Gas production by accelerated in situ bioleaching of landfills  

SciTech Connect

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.

Ghosh, S.

1982-04-06

45

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...

46

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

PubMed

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

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

2014-05-01

47

Landfill Gas Energy Utilization: Technical and Non-Technical Considerations.  

National Technical Information Service (NTIS)

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. LFG is a medium...

J. G. Pacey M. R. J. Doorn S. A. Thorneloe

1994-01-01

48

Removal and determination of trimethylsilanol from the landfill gas.  

PubMed

The removal and determination of trimethylsilanol (TMSOH) in landfill gas has been studied before and after the special E3000-ITC System. The system works according to principle of temperature swing. The performance of TMSOH and humidity removal was 20% and more than 90%, respectively. The six of active carbons and impinger method were tested on the full-scale landfill in Poland for TMSOH and siloxanes determination. The extraction method and absorption in acetone were used. The concentration of TMSOH and siloxanes were found in range from 23.6 to 29.2 mg/m3 and from 18.0 to 38.9 mg/m3, respectively. The content of TMSOH in biogas originating from landfill was 41% out of all siloxanes. Moreover, the used system is alternative to other existing technique of landfill gas purification. PMID:22033372

Piechota, Grzegorz; Hagmann, Manfred; Buczkowski, Roman

2012-01-01

49

Landfill gas generation and migration: Review of current research II  

SciTech Connect

With regard to gas migration, a field investigation is examining bidirectional gas movement through landfill cover materials by processes of pressure and diffusional flow. The overall purpose of the study is to quantify gas loss from the landfill reservoir by natural venting and air influx due to pumping on recovery wells. Two field sites--a humid site, with vegetated clay cover and a semiarid site with unvegetated sandy silt cover--have been instrumented to examine vertical gas movement through cover materials. Results from the past year's work at the semiarid site indicates that rates of CH/sub 4/ flux out of the landfill surface may be as high as 2 /times/ 10/sup /minus/6/ g cm/sup /minus/2/ sec/sup /minus/1/ (6.3 /times/ 10/sup 2/ Kg m/sup /minus/1/ yr/sup /minus/1/) during dry soil conditions. Such high rates represent both the loss of an energy resource and a significance factor in global warming trends since atmospheric CH/sub 4/ contributes to the greenhouse effect. An independent estimate has suggested that 8--15% of global atmospheric CH/sub 4/ is attributable to landfill sources. The second project is addressing landfill gas generation. The major goal is to develop simple assay techniques to examine the gas production potential of landfilled refuse. Refuse samples extracted from various depths in a landfill are being subjected to Biochemical Methane Production (BMP) assays with periodic qualitative examination of microbial populations. Triplicate assays of unamended refuse (controls) are compared to assays with added moisture, nutrients, and bacterial seed. To date, moisture addition is the single most important variable in stimulating gas production, particularly in samples with visible soil content. 56 refs., 2 figs., 3 tabs.

Bogner, J.; Vogt, M.; Piorkowski, R.

1989-01-01

50

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

Microsoft Academic Search

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

G. P. Mueller

1995-01-01

51

Enhancement of landfill gas production Nanticoke landfill, Binghamton, New York. Final report, October 1983-August 1987  

SciTech Connect

An examination of the effects of landfill gas production enhancement in a field-scale program is presented. The enhancement entailed the use of leachate recycling to promote more conducive environmental conditions for the anaerobic microorganisms so that they would grow more quickly and thus convert the organic fraction of the municipal solid waste to methane at a faster rate. Seven field-scale landfill test cells were constructed and monitored for two years. The major conclusion of the study is that the addition of sludge to municipal solid waste in a landfill environment has a positive effect on quickly establishing a viable anaerobic community, as a result of which methane production rates and leachate quality improve. The appendix includes data from permeability tests.

DiPippo, G.; Leuschner, A.P.

1987-07-01

52

LCA and economic evaluation of landfill leachate and gas technologies.  

PubMed

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 0.013 PE and 0.002 to 0.003 PE respectively). The reason for this is that even if the leachate is treated, slight amounts of contaminants are released through emissions of treated wastewater to surface waters. The largest environmental improvement with regard to the direct cost of the landfill was the capping and leachate treatment system. The capping, though very cheap to establish, gave a huge benefit in lowered impacts, the leachate collection system though expensive gave large benefits as well. The other gas measures were found to give further improvements, for a minor increase in cost. PMID:21435856

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

2011-07-01

53

Landfill gas pretreatment for fuel cell applications  

Microsoft Academic Search

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

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

1994-01-01

54

How landfill gas causes RCRA compliance problems  

Microsoft Academic Search

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

Kerfoot

1996-01-01

55

Landfill gas generation and migration: Review of current research  

SciTech Connect

With regard to gas migration, a field investigation is examining bidirectional gas movement through landfill cover materials by processes of pressure and diffusional flow. The purpose of the study is to quantify gas loss from the landfill reservoir by natural venting and air influx due to pumping on recovery wells. Two field sites - a humid site with clay cover and a semiarid site with sand cover - have been instrumented to examine vertical gas movement through cover materials. Results from the humid site indicate that concentrations of methane, carbon dioxide, oxygen and nitrogen in soil gas vary seasonally with soil moisture; up to 10E5 g methane m/sup -2/ yr/sup -1/ are vented through the cover materials at the humid site (area of 17 ht); and during prolonged wet weather, pressure gradients of more than 2 kPa may develop between the cover materials and top of refuse, indicating that pressure flow is periodically an important mechanism for gas transport. Addressing landfill gas generation, the goal is to develop simple assay techniques to examined the gas production potential of landfilled refuse. Refuse samples extracted from various depths in a landfill are being leached by three different methods to separate microbial mass and substrate. The leachates are being subjected to Biochemical Methane Production (BMP) assays with periodic qualitative examination of microbial populations using fluorescence microscopy of live cultures and scanning electron microscopy (SEM). Triplicate assays of the leachates that produce insignificant quantities of biogas after 90 days incubation are being amended with sucrose, a nutrient broth, or a bacterial seed. Response of gas production to each of the three amendments was similar across all samples, regardless of the leaching method originally employed, with nutrient addition producing the most stable long-term biogas production with the highest methane content. 23 refs., 6 figs., 3 tabs.

Bogner, J.; Rose, C.; Vogt, M.; Gartman, D.

1987-01-01

56

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

SciTech Connect

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.

Mueller, G.P. [Caterpillar Inc., Mossville, IL (United States). Engine Development Div.

1995-10-01

57

Landfill gas energy utilization: Technical and nontechnical considerations  

NASA Astrophysics Data System (ADS)

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. LFG is a medium-heating-value fuel containing trace constituents that require gas pretreatment and energy equipment modifications to operate successfully. There are more than 100 LFG-to-energy projects in the U.S., and their developers and operators have found different ways to minimize the potential problems associated with LFG utilization. The paper also gives an overview of developers and operators of these projects, data of European projects, nontechnical issues such as project barriers and incentives, the relationship between LFG delivery and energy output, active landfill gas developers, and insights on project decision making.

Pacey, J. G.; Doorn, M. R. J.; Thorneloe, S. A.

1994-03-01

58

LANDFILL GAS UTILIZATION--OPTIONS, BENEFITS, AND BARRIERS  

EPA Science Inventory

The paper describes the options for landfill-gas (LFG)-to-energy projects and provides statistics on the U. S. LFG industry. It also provides an overview of the benefits associated with LFG utilization and identifies some of the current barriers in the U. S. that affect LFG utili...

59

A catalytic\\/sorption hybrid process for landfill gas cleanup  

Microsoft Academic Search

Landfill gas (LFG) consists primarily of methane and carbon dioxide and a few percent of Oâ, Nâ, and HâO. It also contains numerous other organic compounds, many containing halogens and sulfur. Such compounds besides being potentially toxic to human, animal, and plant life, in addition present challenges to the further processing of LFG. For example, halogen- and sulfur-containing compounds in

Chuanteng He; R. G. Minet; T. T. Tsotsis; D. J. Herman

1997-01-01

60

The landfill gas activity of the IEA bioenergy agreement  

Microsoft Academic Search

Landfill gas (LFG) is a renewable source of useful energy. Its world wide annual energy potential is in the range of a few hundred TWh. Today it is only marginally exploited. LFG is also an important contributor to the atmospheres CH4-content, it can be estimated to contribute about 25% of the methane coming from anthropogenic sources. In comparison to many

A Lagerkvist

1995-01-01

61

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

SciTech Connect

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).

VANDOR,D.

1999-03-01

62

Landfill Gas Cleanup for Carbonate Fuel Cell Power Generation: Final Report  

SciTech Connect

Landfill gas represents a significant fuel resource both in the United States 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.

Steinfeld, G.; Sanderson, R.

1998-02-01

63

Harnessing land-fill gas from refuse-dumping sites in the UK  

Microsoft Academic Search

A state-of-the-art review is presented for this relatively young technology. The study concerning the cost-effectiveness of land-fill gas, which was carried out by London Brick Landfill++ for Hampshire County Council, provides ample evidence that land-fill gas in the UK has a commercially viable future.

N. Gardner; B. Manley; S. D. Probert

1988-01-01

64

Technical and economic assessment of power generation from landfill gas in South Africa  

Microsoft Academic Search

The paper reports on the technical, economic and environmental assessment of stand-alone and grid connected electricity generation from landfill gas in South Africa. Theoretical models are developed in Matlab to calculate the methane production potential of three Western Cape landfill sites in order to assess their suitability for landfill gas to energy (LFGTE) projects. Then Homer package is used to

K. Sekgoele; S. P. Chowdhury

2011-01-01

65

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

Microsoft Academic Search

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, 90cm depth), topsoil methane oxidation capacity and soil properties were surveyed

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

2011-01-01

66

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

PubMed

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

Qiu, Gang; Li, Liang; Sun, Hongjun

2013-10-01

67

Remote Real-Time Monitoring of Subsurface Landfill Gas Migration  

PubMed Central

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.

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

68

Remote real-time monitoring of subsurface landfill gas migration.  

PubMed

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

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

69

Response of tomato plants to simulated landfill gas mixtures  

SciTech Connect

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

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

1985-01-01

70

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

PubMed

Municipal solid waste is a significant contributor to greenhouse gas emissions through decomposition and life-cycle activities processes. The majority of these emissions are a result of landfilling, which remains the primary waste disposal strategy internationally. As a result, countries have been incorporating alternative forms of waste management strategies such as energy recovery from landfill gas capture, aerobic landfilling (aerox landfills), pre-composting of waste prior to landfilling, landfill capping and composting of the organic fraction of municipal solid waste. As the changing global climate has been one of the major environmental challenges facing the world today, there is an increasing need to understand the impact of waste management on greenhouse gas emissions. This review paper serves to provide an overview on the impact of landfilling (and its various alternatives) and composting on greenhouse gas emissions taking into account streamlined life cycle activities and the decomposition process. The review suggests greenhouse gas emissions from waste decomposition are considerably higher for landfills than composting. However, mixed results were found for greenhouse gas emissions for landfill and composting operational activities. Nonetheless, in general, net greenhouse gas emissions for landfills tend to be higher than that for composting facilities. PMID:19155172

Lou, X F; Nair, J

2009-08-01

71

Landfill gas recovery: should your community consider it  

SciTech Connect

Communities which decide to recover, process, and sell landfill gas as a local, low-cost energy source will also derive significant environmental benefits as well. Getty Synthetic Fuels has been a pioneer in the field of methane gas recovery technology. On the basis of this experience, Getty suggests how communities can benefit in the areas of environment, reduction of odor and hydrocarbon emissions, developing a local energy source, safety, aesthetics, revenue, local employment, and regulatory assistance through services provided by a developer. Many communities may find that the environmental benefits outweigh energy considerations.

Shuput, T.A.

1985-08-01

72

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

NASA Astrophysics Data System (ADS)

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.

Adeyemi, Ayodeji Thompson

73

Earthworm activity in a simulated landfill cover soil shifts the community composition of active methanotrophs.  

PubMed

Landfills represent a major source of methane in the atmosphere. In a previous study, we demonstrated that earthworm activity in landfill cover soil can increase soil methane oxidation capacity. In this study, a simulated landfill cover soil mesocosm (1 m × 0.15 m) was used to observe the influence of earthworms (Eisenia veneta) on the active methanotroph community composition, by analyzing the expression of the pmoA gene, which is responsible for methane oxidation. mRNA-based pmoA microarray analysis revealed that earthworm activity in landfill cover soil stimulated activity of type I methanotrophs (Methylobacter, Methylomonas, Methylosarcina spp.) compared to type II methanotrophs (particularly Methylocystis spp.). These results, along with previous studies of methanotrophs in landfill cover soil, can now be used to plan in situ field studies to integrate earthworm-induced methanotrophy with other landfill management practises in order to maximize soil methane oxidation and reduce methane emissions from landfills. PMID:21925596

Kumaresan, Deepak; Héry, Marina; Bodrossy, Levente; Singer, Andrew C; Stralis-Pavese, Nancy; Thompson, Ian P; Murrell, J Colin

2011-12-01

74

Feasibility of direct on-site conversion of landfill gas to electrical energy at Scholl Canyon landfill, California  

NASA Astrophysics Data System (ADS)

The technical and economic feasibility of direct onsite conversion of landfill gas into electrical energy for distribution through the municipal company's distribution grid is described. The various approaches are evaluated. Each system looked at the preliminary collection system layout, type of processing, and conversion equipment required, conversion efficiencies, total system costs, total energy output per input landfill gas, and overall economic comparisons between alternatives. This led to the selection of the internal combustion engine. The legal constraints on interdepartmental transfers of money and resources, city procedures for coordination between the public works department and public services, procedures for facility operation, and an environmental assessment of each alternative were investigated.

Lofy, R. J.

1981-06-01

75

The impact of gas extraction on landfill-generated methane gas levels  

Microsoft Academic Search

The changes measured in landfill-generated CH4 gas levels in response to continuous pumping from an augered borehole in the refuse are described. The results of statistical analyses of concentration and pressure levels at a series of probes located radially outward from the gas extraction well are used to characterize the temporal and spatial variations. A drawdown curve arising from the

Anthony J. Crutcher; Edward A. McBean; Frank A. Rovers

1981-01-01

76

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

PubMed

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

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

2008-05-01

77

Earthworm activity in a simulated landfill cover soil shifts the community composition of active methanotrophs  

Microsoft Academic Search

Landfills represent a major source of methane in the atmosphere. In a previous study, we demonstrated that earthworm activity in landfill cover soil can increase soil methane oxidation capacity. In this study, a simulated landfill cover soil mesocosm (1 m × 0.15 m) was used to observe the influence of earthworms (Eisenia veneta) on the active methanotroph community composition, by analyzing the expression of

Deepak Kumaresan; Marina Héry; Levente Bodrossy; Andrew C. Singer; Nancy Stralis-Pavese; Ian P. Thompson; J. Colin Murrell

78

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

Microsoft Academic Search

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 (HâS) in the landfill gas formed. However, people

1998-01-01

79

UK (United Kingdom) Landfill Gas and Municipal Solid Waste Digestion Industry.  

National Technical Information Service (NTIS)

In the UK more than 90% of all generated wastes are eventually disposed of to landfill. The biodegradable portions of the waste invariably decompose and produce a methane rich landfill gas. This gas can be exploited and a growing industry is evolving to t...

K. M. Richards

1988-01-01

80

Development of the utilization of combustible gas produced in existing sanitary landfills: Effects of corrosion at the Mountain View, California landfill gas-recovery plant  

NASA Astrophysics Data System (ADS)

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

1982-10-01

81

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

PubMed

With limited assessment, leachate treatment of a specified landfill is considered to be a significant source of greenhouse gas (GHG) emissions. In our study, the cumulative GHG emitted from the storage ponds and process configurations that manage fresh or aged landfill leachate were investigated. Our results showed that strong CH4 emissions were observed from the fresh leachate storage pond, with the fluxes values (2219-26,489mgCm(-2)h(-1)) extremely higher than those of N2O (0.028-0.41mgNm(-2)h(-1)). In contrast, the emission values for both CH4 and N2O were low for the aged leachate tank. N2O emissions became dominant once the leachate entered the treatment plants of both systems, accounting for 8-12% of the removal of N-species gases. Per capita, the N2O emission based on both leachate treatment systems was estimated to be 7.99gN2O-Ncapita(-1)yr(-1). An increase of 80% in N2O emissions was observed when the bioreactor pH decreased by approximately 1 pH unit. The vast majority of carbon was removed in the form of CO2, with a small portion as CH4 (<0.3%) during both treatment processes. The cumulative GHG emissions for fresh leachate storage ponds, fresh leachate treatment system and aged leachate treatment system were 19.10, 10.62 and 3.63GgCO2eqyr(-1), respectively, for a total that could be transformed to 9.09kgCO2eqcapita(-1)yr(-1). PMID:24594255

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

2014-07-01

82

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

SciTech Connect

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.

Steinfield, G.; Sanderson, R.

1998-02-01

83

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

PubMed

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

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

2011-05-01

84

LANDFILL GAS AND ITS INFLUENCE ON GLOBAL CLIMATE CHANGE  

EPA Science Inventory

The chapter describes the relative importance of landfills to global warming and identifies the major sources of uncertainty with current emission estimates. t also provides an overview of EPA's research program on global landfill methane, including developing more reliable estim...

85

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

PubMed

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

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

2010-03-15

86

Recovery and utilization of methane gas from a sanitary landfill: City of Industry, California  

Microsoft Academic Search

The design and installation of a system to recover and utilize methane gas produced in a completed sanitary landfill is described. A 160-acre landfill, completed in 1967, is located within a larger 500-acre parcel owned and currently under development by the City of Industry, California. The overall development includes two 18-hole championship golf courses, golf clubhouse and service facilities, an

R. P. Stearns; T. D. Wright; M. Brecher

2008-01-01

87

CHANGES IN MAJOR AND TRACE COMPONENTS OF LANDFILL GAS DURING SUBSURFACE MIGRATION  

Microsoft Academic Search

A gas plume emanating from the Foxhall Landfill in Suffolk (U.K.) has been defined within unsaturated ferruginous sands on the basis of elevated concentrations of methane, carbon dioxide and volatile organic compounds (VOCs). The plume is relatively narrow, extends more than 100 m from the landfill boundary, and lies mainly between 2 m bgl (below ground level) and the water

R. S. Ward; G. M. Williams; C. C. Hills

1996-01-01

88

Reduced sulfur compounds in gas from construction and demolition debris landfills  

Microsoft Academic Search

The biological conversion of sulfate from disposed gypsum drywall to hydrogen sulfide (H2S) in the anaerobic environment of a landfill results in odor problems and possible health concerns at many disposal facilities. To examine the extent and magnitude of such emissions, landfill gas samples from wells, soil vapor samples from the interface of the waste and cover soil, and ambient

Sue Lee; Qiyong Xu; Matthew Booth; Timothy G. Townsend; Paul Chadik; Gabriel Bitton

2006-01-01

89

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

Microsoft Academic Search

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

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

2010-01-01

90

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

Microsoft Academic Search

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

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

2011-01-01

91

Carbon dioxide removal and capture for landfill gas up-grading  

Microsoft Academic Search

Within the frame of an EC financially supported project - LIFE05 ENV\\/IT\\/000874 GHERL (Greenhouse Effect Reduction from Landfill)–a pilot plant was set up in order to demonstrate the feasibility of applying chemical absorption to remove carbon dioxide from landfill gas. After proper upgrading - basically removal of carbon dioxide, hydrogen sulphide, ammonia and other trace gas compound–the gas might be

Lidia Lombardia; Andrea Corti; Ennio Carnevale; Renato Baciocchi; Daniela Zingaretti

2011-01-01

92

Degradation of starch-plastic composites in a municipal solid waste landfill  

Microsoft Academic Search

The rate and extent of deterioration of starch-plastic composites were determined over a 2-year period for samples buried in a municipal solid waste landfill. The deterioration of the starch-plastic composites following exposure was determined by measuring changes in tensile properties, weight loss, and starch content of samples retrieved from the landfill. Elongation decreases of 92 and 44% were measured for

Vincent T. Breslin

1993-01-01

93

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

PubMed

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

Tufts, Jenia A McBrian; Rosati, Jacky A

2012-02-01

94

Migration and methanogens: A review of current landfill gas field research at ANL  

SciTech Connect

Landfill gas recovery research at Argonne National Laboratory is focusing on a project studying gas movement through landfill cover materials and a pilot investigation of microbial populations in landfills. Vertical gas pressure and concentration gradients between the top of refuse and the landfill cover are being examined. In particular, changes in the vertical gradients indicative of changes in magnitude and direction of pressure or diffusional flow with time are being monitored. This study emphasizes changes in vertical pressure and concentration gradients related to barometric pressure and other meteorological variables, soil moisture changes, and pumping rates at simulated recovery wells. Preliminary results suggest that changes in soil-gas pressures in the landfill cover and top of refuse closely follow changes in barometric pressure. Measurable concentration gradients exist between the top of refuse and the cover materials indicating that diffusion is a major mechanism for gas movement, particularly during dry weather when pressure gradients are negligible. A pilot investigation has begun on microbial populations in sanitary landfills. First, a series of leachate samples from various depths at the Blackwell Forest Preserve Landfill were evaluated for microbial populations, selected chemical constituents, and methane production. Diverse motile populations of fluorescing organisms were found in selected samples. 19 refs., 6 figs., 3 tabs.

Bogner, J.; Torpy, M.; Rose, C.; Vogt, M.; Gartman, D.; Moore, C.

1986-01-01

95

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

SciTech Connect

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, Fleming, and Mulberry coals--are the major coals of sufficient thickness (nominally >1-foot) that can imbibe carbon dioxide gas with an enhanced coalbed injection. Comparison of the adsorption gas content of coals to the gas desorbed from the coals shows that the degree of saturation decreases with depth for the coals.

K. David Newell; Timothy R. Carr

2007-03-31

96

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

National Technical Information Service (NTIS)

A number of techniques are introduced to calculate the hourly indirect emissions benefits of three types of renewable resources: wind energy, Municipal Solid Waste (MSW) combustion, and Landfill Gas (LFG) combustion. These techniques are applied to each o...

B. Biewald E. D. Hausman J. Fisher

2008-01-01

97

US Landfill Gas Resource: Low-Cost Biogas from Municipal Solid Waste.  

National Technical Information Service (NTIS)

This report, Low-cost biogas from municipal solid waste, covers: numbers and volumes of landfills; gas generation rates; methods; and data and results. 23 refs., 2 figs., 5 tabs. (ERA citation 13:050893)

J. E. Bogner

1988-01-01

98

Leachate Collection and Gas Migration and Emission Problems at Landfills and Surface Impoundments.  

National Technical Information Service (NTIS)

Clogging of leachate systems and gas migration and emission problems were evaluated at hazardous waste landfills and surface impoundments. Collective and preventive measures were identified along with research and development needs. The analysis used lite...

K. Crawford M. Ghassemi M. Haro

1986-01-01

99

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

SciTech Connect

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.

Jung, Yoojin; Han, Byunghyun; Mostafid, M. Erfan; Chiu, Pei [Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716 (United States); Yazdani, Ramin [Yolo County Planning and Public Works Department, Division of Integrated Waste Management, Yolo County, 44090 County Rd. 28H, Woodland, CA 95776 (United States); Imhoff, Paul T., E-mail: imhoff@udel.edu [Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716 (United States)

2012-02-15

100

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

SciTech Connect

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.

El-Fadel, Mutasem, E-mail: mfadel@aub.edu.lb [Department of Civil and Environmental Engineering, American University of Beirut (Lebanon); Abi-Esber, Layale; Salhab, Samer [Department of Civil and Environmental Engineering, American University of Beirut (Lebanon)

2012-11-15

101

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

Microsoft Academic Search

To investigate whether landfill leachates affected the microbial biomass and\\/or community composition of the extant microbiota,\\u000a 37 samples were collected along a 305-m transect of a shallow landfill-leachate polluted aquifer. The samples were analyzed\\u000a for total numbers of bacteria by use of the acridine orange direct count method (AODC). Numbers of dominant, specific groups\\u000a of bacteria and total numbers of

L. Ludvigsen; H.-J. Albrechtsen; D. B. Ringelberg; F. Ekelund; T. H. Christensen

1999-01-01

102

Landfill gas-fired power plant pays cost of operating landfill  

Microsoft Academic Search

This paper reports on recovery of energy from refuse that has become increasingly attractive in the past decade. The continuing urbanization of our society has created major challenges in the disposal of our waste products. Because of public concern over the potential presence of toxins, and for other environmental reasons, management and regulation of active and inactive landfills have become

Wallace

1991-01-01

103

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

PubMed

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

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

2014-04-01

104

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

105

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 ...

106

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

SciTech Connect

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.

Jon Creighton

2012-03-13

107

Microbial methane oxidation processes and technologies for mitigation of landfill gas emissions.  

PubMed

Landfill gas containing methane is produced by anaerobic degradation of organic waste. Methane is a strong greenhouse gas and landfills are one of the major anthropogenic sources of atmospheric methane. Landfill methane may be oxidized by methanotrophic microorganisms in soils or waste materials utilizing oxygen that diffuses into the cover layer from the atmosphere. The methane oxidation process, which is governed by several environmental factors, can be exploited in engineered systems developed for methane emission mitigation. Mathematical models that account for methane oxidation can be used to predict methane emissions from landfills. Additional research and technology development is needed before methane mitigation technologies utilizing microbial methane oxidation processes can become commercially viable and widely deployed. PMID:19584243

Scheutz, Charlotte; Kjeldsen, Peter; Bogner, Jean E; De Visscher, Alex; Gebert, Julia; Hilger, Helene A; Huber-Humer, Marion; Spokas, Kurt

2009-08-01

108

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

PubMed

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

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

2006-01-01

109

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

SciTech Connect

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.

Spokas, K. [University of Minnesota, Department of Soil, Water, and Climate, St. Paul, MN (United States)]. E-mail: spokas@morris.ars.usda.gov; Bogner, J. [Landfills Inc., Wheaton, Illinois and University of Illinois, Chicago, IL (United States); Chanton, J.P. [Florida State University, Department of Oceanography, Tallahassee, FL (United States); Morcet, M. [Centre de Recherches pour l'Environnement l'Energie et le Dechet (CReeD), Veolia Environnement, Limay (France); Aran, C. [Centre de Recherches pour l'Environnement l'Energie et le Dechet (CReeD), Veolia Environnement, Limay (France); Graff, C. [University of Minnesota, Department of Soil, Water, and Climate, St. Paul, MN (United States); Golvan, Y. Moreau-Le [COLLEX Pty Ltd., CReeD, Veolia Environnement, Pyrmont NSW (Australia); Hebe, I. [Agence de l'Environnement et de la Maitrise de l'Energie (ADEME), French Agency for the Environment and Energy Management, Angers (France)

2006-07-01

110

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

SciTech Connect

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 systems, the Project established new national standards for best available control technology (BACT). 3) The Project will annually produce 365,292 MWh?s of clean energy. 4) By destroying the methane in the landfill gas, the Project will generate CO{sub 2} equivalent reductions of 164,938 tons annually. The completed facility produces 28.3 MWnet and operates 24 hours a day, seven days a week.

Galowitz, Stephen

2013-06-30

111

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

Microsoft Academic Search

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

Martin Schweigkofler; Reinhard Niessner

1999-01-01

112

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

PubMed

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

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

2012-02-01

113

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

NASA Astrophysics Data System (ADS)

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.

Reshetyuk, Yuriy; Mårtensson, Stig-Göran

2014-04-01

114

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

PubMed

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

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

2008-01-01

115

Use of land-fill gas to stimulate crude oil production and to recover methane-rich gas  

Microsoft Academic Search

Land-fill gas containing principally methane and carbon dioxide is injected into a partially depleted oil reservoir to stimulate crude oil production. Solution of injected gas, especially carbon dioxide, in the crude oil materially reduces its viscosity which together with pressurization increases oil flow. Gas separated from produced oil is fractionated into valuable methane-rich gas and carbon dioxide-rich gas which is

Garbo

1982-01-01

116

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

Microsoft Academic Search

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

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

2006-01-01

117

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

SciTech Connect

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.

Hodgson, A.T.; Garbesi, K.; Sextro, R.G.; Daisey, J.M. (Lawrence Berkeley Lab., CA (United States))

1992-03-01

118

A Comprehensive Numerical Model Simulating Gas, Heat, and Moisture Transport in Sanitary Landfills and Methane Oxidation in Final Covers  

Microsoft Academic Search

A model to simulate gas, heat, and moisture transport through a sanitary landfill has been developed. The model not only considers\\u000a the different processes that go on in a landfill but also the oxidation of methane in the final cover. The model was calibrated\\u000a using published results and field data from a pilot scale landfill in Calgary. The model captures

Anurag Garg; Gopal Achari

2010-01-01

119

Physicochemical properties of palm oil fuel ash as composite sorbent in kaolin clay landfill liner system  

Microsoft Academic Search

This paper presents the physico-chemical properties of palm oil fuel ash (POF A) a biomass residue, while justifying its use as composite sorbent when admixed with kaolin clay, for the purpose of designing composite sanitary landfill liner. Laboratory analysis conducted centered on properties of sundried raw POF A passing through 150J1.m, 75J1.m, 38J1.m test sieves, and of the fine ground

Oyeleke Raifu Brown; Mohd Badruddin Bin Mohd Yusof; Mohd Razman Bin Salim; Kamaruddin Ahmed

2011-01-01

120

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

Microsoft Academic Search

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

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

2010-01-01

121

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...

122

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 ...

123

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

SciTech Connect

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.

Reichenauer, Thomas G., E-mail: thomas.reichenauer@ait.ac.at [Health and Environment Department, Environmental Resources and Technologies, AIT - Austrian Institute of Technology GmbH, 2444 Seibersdorf (Austria); Watzinger, Andrea; Riesing, Johann [Health and Environment Department, Environmental Resources and Technologies, AIT - Austrian Institute of Technology GmbH, 2444 Seibersdorf (Austria); Gerzabek, Martin H. [Institute of Soil Research, Department of Forest and Soil Sciences, University of Natural Resources and Applied Life Sciences, Peter Jordan-Strasse 82, 1190 Vienna (Austria)

2011-05-15

124

Methane oxidation activity and bacterial community composition in a simulated landfill cover soil is influenced by the growth of Chenopodium album L  

Microsoft Academic Search

Oxygen availability in landfill cover soil is a major limitation to the growth and activity of methanotrophs as methane oxidation is an aerobic microbial process. Plants tolerant to high concentrations of landfill gas (LFG) may play an important role in improving methane oxidation within landfill cover soil and reducing emission of methane, a greenhouse gas, from it. In this study,

Yunlong Wang; Weixiang Wu; Ying Ding; Wei Liu; Anton Perera; Yingxu Chen; Medha Devare

2008-01-01

125

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

Microsoft Academic Search

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

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

2009-01-01

126

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

Microsoft Academic Search

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

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

2010-01-01

127

Cannock landfill gas powering a small tubular solid oxide fuel cell — a case study  

NASA Astrophysics Data System (ADS)

Cannock landfill gas — mainly a mixture of methane and carbon dioxide — can successfully power a small tubular solid oxide fuel cell. Initial experiments showed a relatively rapid falling off in power due to poisoning with hydrogen sulphide. A simple de-sulphurisation system alleviated this problem. Even greater performance was achieved by the pre-addition of air to help in the reforming of the gas, giving little loss of power over the lifetime of the experiment.

Staniforth, J.; Kendall, K.

128

Leachate Composition and Groundwater Pollution at Municipal Solid Waste Landfill of Ibb City, Yemen (Komposisis Larut Lesap Bahan Buangan dan Pencemaran Air Bawah Tanah di Tapak Pelupusan Sisa Pepejal Bandar Ibb, Yemen)  

Microsoft Academic Search

Compositions of landfill leachate and groundwater pollution were studied at Ibb landfill, which is located at Al-Sahool area, north of Ibb City, Yemen. The leachate was sampled at three different locations at the landfill, i.e. at the landfill itself and at 15 and 20 m downstream of the landfill. Groundwater samples were collected from five boreholes to study the possible

S. ABduL; W. Y. WAn RahIm

129

Case Study Demonstrating US EPA Guidance for Evaluating Landfill Gas Emissions from Closed or Abandoned Facilities: Bush Valley Landfill, Harford County, Maryland.  

National Technical Information Service (NTIS)

This report describes a case study that applies EPA-600/R-05/123Cthe 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 potentiall...

2005-01-01

130

Gas pressure and concentration gradients at the top of a landfill  

SciTech Connect

Vertical gas pressure and concentration gradients are being investigated at the Mallard North Landfill (DuPage County, Illinois) using nests of probes installed in the top of refuse and at two depths in the clay cover materials. Soil gas pressures and atmospheric pressure are monitored continuously using electronic pressure transducers linked to a microcomputer. Concentrations of methane, carbon dioxide, nitrogen, and oxygen in the soil gas are determined using a field gas chromatograph. Supporting meteorological, soil temperature, and soil moisture data also are obtained. Based on data from the fall of 1985 and the spring, summer, and fall of 1986, soil gas pressures at all depths responded to changes in barometric pressure; however, the type of response varied, depending on soil moisture and temperature. During warm, dry weather, for example, soil gas pressures in the cover and the top of the refuse equilibrate rapidly with barometric pressure, indicating that diffusion is the major mechanism for gas transport at that time (no pressure gradients). The rate of diffusional flow depends on the properties of the cover materials, as well as the concentration gradients. Increases in soil moisture, in particular, decrease the gas-filled porosity of the cover materials and retard gas movement. Our results suggest that design and maintenance of tighter landfill covers should be considered at sites where gas recovery is anticipated, to prevent loss of methane and influx of oxygen.

Bogner, J.; Vogt, M.; Moore, C.; Gartman, D.

1987-01-01

131

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 ...

132

Landfill bioreactor design and operation  

SciTech Connect

Landfill Bioreactor Design and Operation covers the history and background of landfill technology, research studies of actual bioreactor landfills, expected leachate and gas yields, specific design criteria, operation guidelines, and reuse of landfill sites to avoid having to establish new sites. For anyone looking for an alternative to large, wasteful landfill sites, this book provides a practical alternative to the problem.

Reinhart, D.R. [Univ. of Central Florida, Orlando, FL (United States); Townsend, T. [Univ. of Florida, Gainesville, FL (United States)

1998-12-31

133

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

USGS Publications Warehouse

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 were in the southern part of the study area to the west of the debris field. However, all other detections of total petroleum hydrocarbons greater than 10 micrograms and diesel greater than 0.04 micrograms, and all detections of the combined mass of benzene, toluene, ethylbenzene, and xylene were found down slope from the debris field in the central and northern parts of the study area. Five soil-gas samplers were deployed and recovered from September 16 to 22, 2010, and were analyzed for organic compounds classified as chemical agents or explosives. Chloroacetophenones (a tear gas component) were the only compounds detected above a method detection level and were detected at the same location as the highest total petroleum hydrocarbons and diesel detections in the southern part of the 14-acre study area. Composite soil samples collected at five locations were analyzed for 35 inorganic constituents. None of the inorganic constituents exceeded the regional screening levels. One surface-water sample collected in the western end of the hyporheic-zone study area had a trichlorofluoromethane concentration above the laboratory reporting level and estimated concentrations of chloroform, fluoranthene, and isophorone below laboratory reporting levels.

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

2011-01-01

134

Effect of biogas generation on radon emissions from landfills receiving radium-bearing waste from shale gas development.  

PubMed

Dramatic increases in the development of oil and natural gas from shale formations will result in large quantities of drill cuttings, flowback water, and produced water. These organic-rich shale gas formations often contain elevated concentrations of naturally occurring radioactive materials (NORM), such as uranium, thorium, and radium. Production of oil and gas from these formations will also lead to the development of technologically enhanced NORM (TENORM) in production equipment. Disposal of these potentially radium-bearing materials in municipal solid waste (MSW) landfills could release radon to the atmosphere. Risk analyses of disposal of radium-bearing TENORM in MSW landfills sponsored by the Department of Energy did not consider the effect of landfill gas (LFG) generation or LFG control systems on radon emissions. Simulation of radon emissions from landfills with LFG generation indicates that LFG generation can significantly increase radon emissions relative to emissions without LFG generation, where the radon emissions are largely controlled by vapor-phase diffusion. Although the operation of LFG control systems at landfills with radon source materials can result in point-source atmospheric radon plumes, the LFG control systems tend to reduce overall radon emissions by reducing advective gas flow through the landfill surface, and increasing the radon residence time in the subsurface, thus allowing more time for radon to decay. In some of the disposal scenarios considered, the radon flux from the landfill and off-site atmospheric activities exceed levels that would be allowed for radon emissions from uranium mill tailings. Implications: Increased development of hydrocarbons from organic-rich shale formations has raised public concern that wastes from these activities containing naturally occurring radioactive materials, particularly radium, may be disposed in municipal solid waste landfills and endanger public health by releasing radon to the atmosphere. This paper analyses the processes by which radon may be emitted from a landfill to the atmosphere. The analyses indicate that landfill gas generation can significantly increase radon emissions, but that the actual level of radon emissions depend on the place of the waste, construction of the landfill cover, and nature of the landfill gas control system. PMID:23019818

Walter, Gary R; Benke, Roland R; Pickett, David A

2012-09-01

135

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

PubMed

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

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

2011-05-01

136

Quantifying methane oxidation in a landfill-cover soil by gas push-pull tests  

SciTech Connect

Methane (CH{sub 4}) oxidation by aerobic methanotrophs in landfill-cover soils decreases emissions of landfill-produced CH{sub 4} to the atmosphere. To quantify in situ rates of CH{sub 4} oxidation we performed five gas push-pull tests (GPPTs) at each of two locations in the cover soil of the Lindenstock landfill (Liestal, Switzerland) over a 4 week period. GPPTs consist of the injection of a gas mixture containing CH{sub 4}, O{sub 2} and noble gas tracers followed by extraction from the same location. Quantification of first-order rate constants was based upon comparison of breakthrough curves of CH{sub 4} with either Ar or CH{sub 4} itself from a subsequent inactive GPPT containing acetylene as an inhibitor of CH{sub 4} oxidation. The maximum calculated first-order rate constant was 24.8 {+-} 0.8 h{sup -1} at location 1 and 18.9 {+-} 0.6 h{sup -1} at location 2. In general, location 2 had higher background CH{sub 4} concentrations in vertical profile samples than location 1. High background CH{sub 4} concentrations in the cover soil during some experiments adversely affected GPPT breakthrough curves and data interpretation. Real-time PCR verified the presence of a large population of methanotrophs at the two GPPT locations and comparison of stable carbon isotope fractionation of CH{sub 4} in an active GPPT and a subsequent inactive GPPT confirmed that microbial activity was responsible for the CH{sub 4} oxidation. The GPPT was shown to be a useful tool to reproducibly estimate in situ rates of CH{sub 4} oxidation in a landfill-cover soil when background CH{sub 4} concentrations were low.

Gomez, K.E. [Institute of Biogeochemistry and Pollutant Dynamics, ETH Zuerich, Universitaetstrasse 16, 8092 Zuerich (Switzerland)], E-mail: gomezke@hotmail.com; Gonzalez-Gil, G.; Lazzaro, A. [Institute of Biogeochemistry and Pollutant Dynamics, ETH Zuerich, Universitaetstrasse 16, 8092 Zuerich (Switzerland); Schroth, M.H. [Institute of Biogeochemistry and Pollutant Dynamics, ETH Zuerich, Universitaetstrasse 16, 8092 Zuerich (Switzerland)], E-mail: martin.schroth@env.ethz.ch

2009-09-15

137

Quantifying methane oxidation in a landfill-cover soil by gas push-pull tests.  

PubMed

Methane (CH(4)) oxidation by aerobic methanotrophs in landfill-cover soils decreases emissions of landfill-produced CH(4) to the atmosphere. To quantify in situ rates of CH(4) oxidation we performed five gas push-pull tests (GPPTs) at each of two locations in the cover soil of the Lindenstock landfill (Liestal, Switzerland) over a 4 week period. GPPTs consist of the injection of a gas mixture containing CH(4), O(2) and noble gas tracers followed by extraction from the same location. Quantification of first-order rate constants was based upon comparison of breakthrough curves of CH(4) with either Ar or CH(4) itself from a subsequent inactive GPPT containing acetylene as an inhibitor of CH(4) oxidation. The maximum calculated first-order rate constant was 24.8+/-0.8 h(-1) at location 1 and 18.9+/-0.6 h(-1) at location 2. In general, location 2 had higher background CH(4) concentrations in vertical profile samples than location 1. High background CH(4) concentrations in the cover soil during some experiments adversely affected GPPT breakthrough curves and data interpretation. Real-time PCR verified the presence of a large population of methanotrophs at the two GPPT locations and comparison of stable carbon isotope fractionation of CH(4) in an active GPPT and a subsequent inactive GPPT confirmed that microbial activity was responsible for the CH(4) oxidation. The GPPT was shown to be a useful tool to reproducibly estimate in situ rates of CH(4) oxidation in a landfill-cover soil when background CH(4) concentrations were low. PMID:19525106

Gómez, K E; Gonzalez-Gil, G; Lazzaro, A; Schroth, M H

2009-09-01

138

Development of the utilization of combustible gas produced in existing sanitary landfills: investigation of effects of air inclusion  

SciTech Connect

A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A practical consequence of the collection of this fuel gas is the inclusion of some air in the collected product. The effects of such included nitrogen and oxygen on landfill gas operations are discussed. The effects include increased collection and purification costs, reduction in the quality of the fuel gas produced, corrosion, explosion hazards, and interference with odorant systems. The scope of such effects was determined using data and experience from the Mountain View, California, landfill gas recovery site as a basis. Useful supplemental fuel gas may be recovered despite the inclusion of air. Recommendations are given for establishing limits for nitrogen and oxygen content and minimizing the costs associated with their presence.

Not Available

1983-01-01

139

Development of the utilization of combustible gas produced in existing sanitary landfills: Investigation of effects of air inclusion  

NASA Astrophysics Data System (ADS)

The effects of nitrogen and oxygen on landfill gas operations are discussed. A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A consequence of the collection of this fuel gas is the inclusion of some air in the collected product. The effects include increased collected and purification costs, reduction in the quality of the fuel gas produced, corrosion, explosion hazards, and interference with odorant systems. The scope of such effects was determined by using landfill data of a gas recovery site as a basis. Useful supplemental fuel gas may be recovered despite the inclusion of air. Recommendations are made for establishing limits for nitrogen and oxygen content and minimizing the costs associated with their presence.

1983-01-01

140

Natural attenuation and characterization of contaminants composition in landfill leachate under different disposing ages.  

PubMed

Chemical Oxygen Demand (COD) composition in landfill leachate would vary as the disposal time extended. Leachates with different ages were collected from Laogang Refuse Landfill of Shanghai, the largest landfill in China with a placement scale of 7600 t refuse per day. To characterize COD composition in leachate, samples were size-fractioned into suspended fractions (>0.45 microm), colloid fraction (0.45 micromlandfill leachate treatment process should be modified according to the leachate characterization. The results obtained in this study might provide the important information for modeling, design, and operation of landfill leachate treatment systems. PMID:19217144

Ziyang, Lou; Youcai, Zhao; Tao, Yuan; Yu, Song; Huili, Chen; Nanwen, Zhu; Renhua, Huan

2009-05-01

141

Fuel gas recovery from controlled landfilling of municipal wastes  

Microsoft Academic Search

Experiments were carried out in unstirred reactors for the digestion to fuel gas of shredded municipal solid waste and sewage sludge at high total solids concentration. Waste and sludge solids together comprised up to 48 percent by weight of the reactor contents. Finely divided calcium carbonate dispersed in the aqueous phase was employed as a pH buffer. Results of experiments

D. C. Augenstein; D. L. Wise; R. L. Wentworth; C. L. Cooney

1976-01-01

142

Trace gas compound emissions from municipal landfill sanitary sites  

NASA Astrophysics Data System (ADS)

The literature on certain aspects of trace gas compounds emitted from Municipal Landill Sanitary Sites is reviewed. Aspects covered are the formation, nature and origin of such compounds, as well as the problems caused by them. Risks posed to human health and the environment by even low concentrations of these compounds are examined and methods to reduce and control them discussed.

Brosseau, Josée; Heitz, Michèle

143

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

SciTech Connect

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.

McVey, M.D.; Goering, T.J. [GRAM, Inc., Albuquerque, NM (United States); Peace, J.L. [Sandia National Labs., Albuquerque, NM (United States)

1996-02-01

144

PILOT SCALE EVALUATION OF SLUDGE LANDFILLING: FOUR YEARS OF OPERATION  

EPA Science Inventory

A sludge landfill simulator program consisting of 28 lysimeters was used to evaluate sludge landfilling as a disposal option by assessing the environmental impacts on leachate composition and gas production. The disposal scenarios investigated were codisposal, refuse-only, and sl...

145

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

PubMed

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

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

2013-03-01

146

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

NASA Astrophysics Data System (ADS)

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. From all the analysis performed, a large variability of the results may be observed for both gases and ionic composition not only among the wells, but also among the different depth levels. Vertically, one of the wells (W2) showed the same percentage of gases, methane 55% and carbon dioxide 45%, at all depth levels, while the other two wells (W1 and W3) presented these gases percentages only under 5.0 m deep. Concerning oxygen, 25% of this gas was detected at 1.0 m under the surface in W1 and W3. In relation to aqueous samples, the most acidity was observed near the surface (0.60 m deep, W1), pH 4.65, while pH 7.88 was obtained under 5.0 m deep (W3). For ionic concentrations a large range was observed considering all wells, being the lowest values for sulfate, from 0.60 to 20 mg/l, and the highest values for ammonium, between 14 and 53 mg/l. These results variability can be associated to the different soil composition layers, as well as to the biodegradation process and the time confinement of the river material deposit.

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

2012-04-01

147

Development of the Utilization of Combustible Gas Produced in Existing Sanitary Landfills. Investigation of Effects of Air Inclusion.  

National Technical Information Service (NTIS)

A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A practical consequence of the collection of this fuel gas is the inclusion of some air in the collected product. This report discusses the e...

1981-01-01

148

Development of the Utilization of Combustible Gas Produced in Existing Sanitary Landfills: Investigation of Effects of Air Inclusion.  

National Technical Information Service (NTIS)

A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A practical consequence of the collection of this fuel gas is the inclusion of some air in the collected product. The effects of such include...

1983-01-01

149

Accelerated methane oxidation cover system to reduce greenhouse gas emissions from MSW landfills in cold, semi-arid regions  

Microsoft Academic Search

Many regional landfills for municipal solid waste (MSW) and industrial, commercial, institutional (ICI) wastes in cold, dry regions do not produce enough gas to support conventional gas extraction, treatment, and utilization or flaring. Yet, some solution is required to reduce emissions of methane and trace constituents to the atmosphere for the protection of the public and of the global climate.

Chris A Zeiss

2006-01-01

150

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

EPA Science Inventory

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

151

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

USGS Publications Warehouse

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 samplers had TPH concentrations greater than 100 micrograms per liter. TPH concentrations declined from 320 micrograms per liter in a sampler near the landfill to 18 micrograms in a sampler near the wetland. Five of the samplers had detections of one or more diesel compounds but detections of individual diesel compounds had concentrations below a method detection level of 0.01 microgram per liter. Benzene was detected in three samplers and exceeded the national primary drinking-water standard of 5 micrograms per liter set by the U.S. Environmental Protection Agency. The concentrations of benzene, and therefore BTEX, were 6.1 micrograms per liter in the sampler near the eastern corner of the landfill, 27 micrograms per liter in the sampler near the wetland, and 37 micrograms per liter in the sampler at the southern corner of the landfill. Nonfuel-related compounds were detected in the four wells that are aligned between the eastern corner of the landfill and the wetland. The sampler deployed nearest the eastern corner of the landfill had the greatest number of detected organic compounds and had the only detections of two trimethylbenzene compounds, naphthalene, 2-methyl naphthalene, and 1,4-dichlorobenzene. The two up gradient samplers had the greatest number of chlorinated compounds with five compounds each, compared to detections of four compounds and one compound in the two down gradient samplers. All four samplers had detections of 1,1-dichloroethane which ranged from 42 to 1,300 micrograms per liter. Other detections of chlorinated compounds included trichloroethene, perchloroethene, cis-1,2-dichloroethene, 1,1,1-trichloroethane and chloroform.

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

2012-01-01

152

Measuring Water in Bioreactor Landfills  

Microsoft Academic Search

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

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

2004-01-01

153

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

PubMed

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

Levis, James W; Barlaz, Morton A

2011-07-01

154

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

USGS Publications Warehouse

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 (?g) in all 48 samplers and exceeded 0.9 ?g 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 ?g, 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 area. All samplers in the survey had detections of TPH, but only eight of the samplers had detections of TPH greater than 0.9 mg. Four samplers had TPH detections greater than 9 mg; the only other fuel-related compounds detected in these four samplers included toluene in three of the samplers and undecane in the fourth sampler. Three samplers deployed along the western margin of the northern landfill had detections of both diesel-and gasoline-related compounds; however, the diesel-related compounds were detected at or below method detection levels. Seven samplers in the northern study area had detections of chlorinated compounds, including three perchloroethene detections, three chloroform detections, and one 1,4-dichloro-benzene detection. One sampler on the western margin of the landfill had detections of 1,2,4-trimethylbenzene and 1,3,5-tr-methylbenene below method detection levels.

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

2012-01-01

155

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

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

156

Methylated mercury species in municipal waste landfill gas sampled in Florida, USA1  

Microsoft Academic Search

Mercury-bearing material has been placed in municipal landfills from a wide array of sources including fluorescent lights, batteries, electrical switches, thermometers, and general waste. Despite its known volatility, persistence, and toxicity in the environment, the fate of mercury in landfills has not been widely studied. The nature of landfills designed to reduce waste through generation of methane by anaerobic bacteria

S. E. Lindberga; D. Wallschl; E. M. Prestbob; D. Reinhartd; Frontier Geosciences

157

Simulation model for gas diffusion and methane oxidation in landfill cover soils  

Microsoft Academic Search

Landfill cover soils oxidize a considerable fraction of the methane produced by landfilled waste. Despite many efforts this oxidation is still poorly quantified. In order to reduce the uncertainties associated with methane oxidation in landfill cover soils, a simulation model was developed that incorporates Stefan–Maxwell diffusion, methane oxidation, and methanotrophic growth. The growth model was calibrated to laboratory data from

Alex De Visscher; Oswald Van Cleemput

2003-01-01

158

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...

159

Acceleration of landfill stabilization using leachate recycle  

Microsoft Academic Search

A leachate recycle system was constructed and operated at an existing lined landfill in North-Central Florida to observe the effects of leachate recycle on landfill stabilization. Samples of leachate, landfill gas, and landfilled solid waste were collected and analyzed throughout a four-year period, before and after the start of leachate recycle. The settlement of landfilled waste was also measured in

T. G. Townsend; W. L. Miller; Hyung-Jib Lee; J. F. K. Earle

1996-01-01

160

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

SciTech Connect

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.

Steinfeld, G.; Sanderson, R.

1998-02-01

161

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

USGS Publications Warehouse

Soil gas, soil, and water were assessed for organic and inorganic constituents at the former 19th Street landfill at Fort Gordon, Georgia, from February to September 2010. Passive soil-gas samplers were analyzed to evaluate organic constituents in the hyporheic zone and flood plain of a creek 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. The passive soil-gas samplers deployed in the water-saturated hyporheic zone and flood plain of the creek adjacent to the former landfill indicated the presence of total petroleum hydrocarbon (TPH) and octane above method detection levels in groundwater beneath the creek bed and flood plain at all 12 soil-gas sampler locations. The TPH concentrations ranged from 51.4 to 81.4 micrograms per liter. Octane concentrations ranged from 1.78 to 2.63 micrograms per liter. These detections do not clearly identify specific source areas in the former landfill; moreover, detections of TPH and octane in a soil-gas sampler installed at a seep on the western bank of the creek indicated the potential for these constituents to be derived from source areas outside the estimated boundaries of the former landfill. A passive soil-gas sampler survey was conducted in the former landfill from June 30 to July 5, 2010, and involved 56 soil-gas samplers that were analyzed for petroleum and halogenated compounds not classified as chemical agents or explosives. The TPH soil-gas mass exceeded 2.0 micrograms in 21 samplers. Most noticeable are the two sites with TPH detections which are located in and near the hyporheic zone and are likely to affect 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

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

2011-01-01

162

Measuring seasonal variations of moisture in a landfill with the partitioning gas tracer test.  

PubMed

Seven pilot-scale partitioning gas tracer tests (PGTTs) were conducted to assess the accuracy and reproducibility of this method for measuring water in municipal solid waste landfills. Tests were conducted in the same location over a 12-month period, and measured moisture conditions ranged from possible dry waste to refuse with a moisture content of 24.7%. The final moisture content of 24.7% was in reasonable agreement with gravimetric measurements of excavated refuse, where the moisture content was 26.5+/-6.0 CI%. Laboratory tests were used to assess the utility of the PGTT for measuring water in small pores, water sorbed to solid surfaces, and the influence of dry waste on PGTTs. These experiments indicated that when refuse surfaces are not completely solvated with water, PGTTs may produce misleading results (negative estimates) of water saturation and moisture content. PMID:16458495

Han, Byunghyun; Jafarpour, Behnam; Gallagher, Victoria N; Imhoff, Paul T; Chiu, Pei C; Fluman, Daniel A

2006-01-01

163

Measuring seasonal variations of moisture in a landfill with the partitioning gas tracer test  

SciTech Connect

Seven pilot-scale partitioning gas tracer tests (PGTTs) were conducted to assess the accuracy and reproducibility of this method for measuring water in municipal solid waste landfills. Tests were conducted in the same location over a 12-month period, and measured moisture conditions ranged from possible dry waste to refuse with a moisture content of 24.7%. The final moisture content of 24.7% was in reasonable agreement with gravimetric measurements of excavated refuse, where the moisture content was 26.5 {+-} 6.0CI%. Laboratory tests were used to assess the utility of the PGTT for measuring water in small pores, water sorbed to solid surfaces, and the influence of dry waste on PGTTs. These experiments indicated that when refuse surfaces are not completely solvated with water, PGTTs may produce misleading results (negative estimates) of water saturation and moisture content.

Han, Byunghyun [Department of Civil and Environmental Engineering, University of Delaware, 301 DuPont Hall, Newark, DE 19716 (United States); Jafarpour, Behnam [Department of Civil and Environmental Engineering, University of Delaware, 301 DuPont Hall, Newark, DE 19716 (United States); Gallagher, Victoria N. [Department of Civil and Environmental Engineering, University of Delaware, 301 DuPont Hall, Newark, DE 19716 (United States); Imhoff, Paul T. [Department of Civil and Environmental Engineering, University of Delaware, 301 DuPont Hall, Newark, DE 19716 (United States)]. E-mail: imhoff@udel.edu; Chiu, Pei C. [Department of Civil and Environmental Engineering, University of Delaware, 301 DuPont Hall, Newark, DE 19716 (United States); Fluman, Daniel A. [Delaware Solid Waste Authority, 1128 S. Bradford St. Dover, DE 19903-0455 (United States)

2006-07-01

164

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

PubMed

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

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

2013-01-01

165

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

PubMed

Leachate, the hazardous liquid that percolated through the refuse layers of a sanitary landfill, if it leaks through the landfill lining system, can become a serious source of groundwater pollution. In the past, leaks have been detected in many landfills lined with flexible membrane liners (FML) whose failure may be attributed to flaws such as imperfect seaming, rips, and tears of the membrane, or from chemical attack that dissolves the membrane. Recent studies have shown that composite lining systems which include either a clayey subbase or a layer of geotextile in addition to the FML, can substantially reduce the leakage of leachate. Therefore in this study, four different lining systems are proposed and evaluated to determine their effectiveness in controlling leachate flow under various degree of flaws (referred to as leakage fraction LF) in the FML. The Hydrologic Evaluation of Landfill Performance (HELP) computer model of the Environmental Protection Agency of USA, currently the most widely accepted model for predicting the performance of leachate collection systems in that country, is used to evaluate the following lining systems: (1) a single FML or liner, (2) a single FML with a clayey composite, (3) a single FML with a geotextile called Claymax, and (4) a double FML. Based on the climatic conditions and the present lining construction cost of Alaska, the study shows that a single FML or liner is the most economical but it is also the least effective in controlling leachate flow. Design (3), a single FML with a geotextile, costs about 50 percent more but it reduces the leakage of leachate by several orders. Design (2) is also effective but the cost incurred in constructing a 3 feet thick clayey subbase is prohibitive and thus to effectively and economically minimize the hazards of potential groundwater contamination by leachate, Design (3) is recommended as the composite lining system for future landfill sites. PMID:24233939

Gan, T Y; Friesen, G

1991-10-01

166

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

NASA Astrophysics Data System (ADS)

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.

Zhang, Yuanyuan; Yue, Dongbei; Nie, Yongfeng

2012-08-01

167

Simultaneous removal of NO(x) and SO2 in exhausted gas through landfill leachate.  

PubMed

Simultaneous removal of NO(x) and SO2 from exhausted gas were investigated by studying co-culture of sulfate reducing bacteria and anaerobic denitrifying bacteria, separated from landfill leachate. When H2S, generated by sulfate reducing bacteria was chosen as the sole electron donor for anaerobic denitrifying bacteria, the co-culture system demonstrated a faster NO removal rate, higher stability and better permanence. When the feed gas flow rates of N2 and SO2 were maintained constant at 0.1 m3/h and 16 ml/min respectively, the maximum NO-removal rate could be achieved at over 92% with NO feed gas kept between 2-6 ml/min, while the SO2 removal rate was always above 95%. Long-term continuous removal of NO exhibited an evident periodicity of five days, however, the fluctuation range of NO-removal was decreasing. Moreover, the decrease of the gas flow rate and the increase in NO inlet concentration could contribute to a higher NO- removal rate. PMID:21250607

Han, Yaqiong; Zhang, Weijiang

2010-12-01

168

Use of gas push–pull tests for the measurement of methane oxidation in different landfill cover soils  

Microsoft Academic Search

In order to optimise methane oxidation in landfill cover soils, it is important to be able to accurately quantify the amount of methane oxidised. This research considers the gas push–pull test (GPPT) as a possible method to quantify oxidation rates in situ. During a GPPT, a gas mixture consisting of one or more reactive gases (e.g., CH4, O2) and one

Jan Streese-Kleeberg; Ingke Rachor; Julia Gebert; Rainer Stegmann

2011-01-01

169

Seasonal alterations of landfill leachate composition and toxic potency in semi-arid regions.  

PubMed

The present study investigates seasonal variations of leachate composition and its toxic potency on different species, such as the brine shrimp Artemia franciscana (formerly Artemia salina), the fairy shrimp Thamnocephalus platyurus, the estuarine rotifer Brachionus plicatilis and the microalgal flagellate Dunaliella tertiolecta. In specific, leachate regularly collected from the municipal landfill site of Aigeira (Peloponissos, Greece) during the year 2011, showed significant alterations of almost all its physicochemical parameters with time. Further analysis showed that seasonal alterations of leachate composition are related with the amount of rainfall obtained throughout the year. In fact, rainfall-related parameters, such as conductivity (Cond), nitrates (NO(3)(-)), total nitrogen (TN), ammonium (NH(4)-N), total dissolved solids (TDS) and the BOD(5)/NH(4)-N ratio could merely reflect the leachate strength and toxicity, as verified by the significant correlations occurred among each of them with the toxic endpoints, 24 h LC(50) and/or 72 h IC(50), obtained in all species tested. According to the result of the present study, it could be suggested that the aforementioned leachate parameters could be used independently, or in combination as a low-cost effective tools for estimating leachate strength and toxic potency, at least in the case of semi-arid areas such as the most of the Mediterranean countries. PMID:22819480

Tsarpali, Vasiliki; Kamilari, Maria; Dailianis, Stefanos

2012-09-30

170

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

NASA Astrophysics Data System (ADS)

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.

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

171

Present and Long-Term Composition of MSW Landfill Leachate: A Review  

Microsoft Academic Search

The major potential environmental impacts related to landfill leachate are pollution of groundwater and surface waters. Landfill leachate contains pollutants that can be categorized into four groups (dissolved organic matter, inorganic macrocomponents, heavy metals, and xenobiotic organic compounds). Existing data show high leachate concentrations of all components in the early acid phase due to strong decomposition and leaching. In the

Peter Kjeldsen; Morton A. Barlaz; Alix P. Rooker; Anders Baun; Anna Ledin; Thomas H. Christensen

2002-01-01

172

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

PubMed

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. PMID:15869975

Bockreis, A; Steinberg, I

2005-01-01

173

Use of gas push-pull tests for the measurement of methane oxidation in different landfill cover soils.  

PubMed

In order to optimise methane oxidation in landfill cover soils, it is important to be able to accurately quantify the amount of methane oxidised. This research considers the gas push-pull test (GPPT) as a possible method to quantify oxidation rates in situ. During a GPPT, a gas mixture consisting of one or more reactive gases (e.g., CH(4), O(2)) and one or more conservative tracers (e.g., argon), is injected into the soil. Following this, the mixture of injected gas and soil air is extracted from the same location and periodically sampled. The kinetic parameters for the biological oxidation taking place in the soil can be derived from the differences in the breakthrough curves. The original method of Urmann et al. (2005) was optimised for application in landfill cover soils and modified to reduce the analytical effort required. Optimised parameters included the flow rate during the injection phase and the duration of the experiment. 50 GPPTs have been conducted at different landfills in Germany during different seasons. Generally, methane oxidation rates ranged between 0 and 150 g m(soil air)(-3)h(-1). At one location, rates up to 440 g m(soil air)(-3)h(-1) were measured under particularly favourable conditions. The method is simple in operation and does not require expensive equipment besides standard laboratory gas chromatographs. PMID:20971626

Streese-Kleeberg, Jan; Rachor, Ingke; Gebert, Julia; Stegmann, Rainer

2011-05-01

174

Instrumentation for continuous monitoring of meteorological variables and soil gas pressure in landfill cover  

SciTech Connect

To examine changes in soil gas pressure relative to changes in atmospheric pressure and other meteorological variables, weather station sensors and electronic pressure transducers were interfaced with an RCA COSMAC microcomputer. The microcomputer control permitted simultaneous acquisition of pressure and meteorological data on cassette tape. Because the RCA unit uses CMOS circuitry, it can be battery operated, and is therefore well suited for collecting data at remote locations on landfills. A tape I/O board, an A/D converter board and two custom boards were required additions to the basic CDP18S601 board for this application. Meteorological data, including wind speed, wind direction, air temperature, precipitation, and solar radiation, were monitored using a Climatronics EWS system. Barometric pressure and soil gas pressures on subsurface probes were monitored using electronic pressure transducers with a 10 to 20 psia range. Cassette tape output was dumped directly to WYLBUR files on the Argonne National Laboratory (ANL) IBM 3033 mainframe for subsequent data analysis.

Moore, C.; Vogt, M.; Bogner, J.

1986-09-01

175

Effects of compost biocovers on gas flow and methane oxidation in a landfill cover.  

PubMed

Previous publications described the performance of biocovers constructed with a compost layer placed on select areas of a landfill surface characterized by high emissions from March 2004 to April 2005. The biocovers reduced CH(4) emissions 10-fold by hydration of underlying clay soils, thus reducing the overall amount of CH(4) entering them from below, and by oxidation of a greater portion of that CH(4). This paper examines in detail the field observations made on a control cell and a biocover cell from January 1, 2005 to December 31, 2005. Field observations were coupled to a numerical model to contrast the transport and attenuation of CH(4) emissions from these two cells. The model partitioned the biocover's attenuation of CH(4) emission into blockage of landfill gas flow from the underlying waste and from biological oxidation of CH(4). Model inputs were daily water content and temperature collected at different depths using thermocouples and calibrated TDR probes. Simulations of CH(4) transport through the two soil columns depicted lower CH(4) emissions from the biocover relative to the control. Simulated CH(4) emissions averaged 0.0gm(-2)d(-1) in the biocover and 10.25gm(-2)d(-1) in the control, while measured values averaged 0.04gm(-2)d(-1) in the biocover and 14gm(-2)d(-1) in the control. The simulated influx of CH(4) into the biocover (2.7gm(-2)d(-1)) was lower than the simulated value passing into the control cell (29.4gm(-2)d(-1)), confirming that lower emissions from the biocover were caused by blockage of the gas stream. The simulated average rate of biological oxidation predicted by the model was 19.2gm(-2)d(-1) for the control cell as compared to 2.7gm(-2)d(-1) biocover. Even though its V(max) was significantly greater, the biocover oxidized less CH(4) than the control cell because less CH(4) was supplied to it. PMID:19131233

Abichou, Tarek; Mahieu, Koenraad; Yuan, Lei; Chanton, Jeffery; Hater, Gary

2009-05-01

176

Sanitary Landfilling.  

National Technical Information Service (NTIS)

Contents: Introductory remarks; panel a: selecting sanitary landfill sites; how to select and acquire a sanitary landfill site; effects of industrial and hazardous wastes on site location; designing a rural sanitary landfill system; panel b: sanitary land...

J. E. Delaney

1973-01-01

177

Leaky Landfills.  

ERIC Educational Resources Information Center

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)

Jones, Linda L. Cronin

1992-01-01

178

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...

179

Composition for absorbing hydrogen from gas mixtures  

DOEpatents

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.

Heung, Leung K. (Aiken, SC); Wicks, George G. (Aiken, SC); Lee, Myung W. (Aiken, SC)

1999-01-01

180

Analysis of Malodorous Sulfur Gases and Volatile Organometalloid Compounds in Landfill Gas Emissions Using Capillary Gas Chromatography with Programmed Temperature Vaporization Injection and Atomic Emission Detection  

Microsoft Academic Search

Volatile compounds containing Group V and Group VI elements in landfill gases are of concern as a source of toxic pollutants and unpleasant odors. Conventional analytical techniques for these compounds e.g. ICP-MS, ICP-AES are complicated, expensive and time consuming. The use of a simple programmed temperature vaporization injection (PTV) technique coupled to gas chromatography with atomic emission detection (GC-AED) has

Suwannee Junyapoon; Keith Bartle; Andrew Ross; Michael Cooke

2002-01-01

181

Simulation model for gas diffusion and methane oxidation in landfill cover soils.  

PubMed

Landfill cover soils oxidize a considerable fraction of the methane produced by landfilled waste. Despite many efforts this oxidation is still poorly quantified. In order to reduce the uncertainties associated with methane oxidation in landfill cover soils, a simulation model was developed that incorporates Stefan-Maxwell diffusion, methane oxidation, and methanotrophic growth. The growth model was calibrated to laboratory data from an earlier study. There was an excellent agreement between the model and the experimental data. Therefore, the model is highly applicable to laboratory column studies, but it has not been validated with field data. A sensitivity analysis showed that the model is most sensitive to the parameter expressing the maximum attainable methanotrophic activity of the soil. Temperature and soil moisture are predicted to be the environmental factors affecting the methane oxidizing capacity of a landfill cover soil the most. Once validated with field data, the model will enable a year-round estimate of the methane oxidizing capacity of a landfill cover soil. PMID:12957153

De Visscher, Alex; Van Cleemput, Oswald

2003-01-01

182

Superfund record of decision (EPA Region 5): Ripon City Landfill, Fond du Lac County, Ripon, WI, March 27, 1996  

SciTech Connect

The Ripon FF/LN landfill Superfund site is located at the intersection of Highways FF and NN in the Town of Ripon, Fond du Lac County, Wisconsin. The selected source control remedy is Alternative O, Composite Landfill Cap and Passive Gas Venting in conjunction with a groundwater monitoring plan.

NONE

1996-06-01

183

OPERATING STRATEGIES FOR ENHANCING WASTE BIODEGRADATION AND INCORPORATION OF VEGETATED COVERSOIL TO MINIMIZE METHANE GAS EMISSION IN MSW LANDFILL  

Microsoft Academic Search

Recently, a process based approach in landfill design and operation has been developed called bioreactor landfill. A bioreactor landfill is managed to accelerate decomposition of the organic wastes by controlling moisture content, recycling nutrients and seeding of microorganisms by circulating leachate back into the landfill cell. This research investigated the beneficial effect of using this concept in accelerating the biodegradation

C. Chiemchaisri; W. Chiemchaisri; S. Sittichoktam; U. Yodsang; K. Chittanukul

184

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

PubMed

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

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

185

Landfill gas energy utilization experience: Discussion of technical and non-technical issues, solutions, and trends. Final report, January 1992-September 1994  

SciTech Connect

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 U.S. The report also provides the history and trends of the landfill gas industry in the U.S. Graphs illustrate how the influence of reciprocating internal combustion (RIC) engines, compared to other utilization options, has steadily increased over time. The report summarizes information on new landfill gas utilization technologies, including vehicular fuel systems and fuel cells. Overall results of programs to demonstrate the operational feasibility of innovative technologies appear quite promising. Some of the non-technical problems and solutions described in the report are associated with the development of energy utilization options including project economics, barriers, and incentives.

Doorn, M.; Pacey, J.; Augenstein, D.

1995-03-01

186

Electric power generation from landfill gas using traditional and innovative technologies  

Microsoft Academic Search

Energy recovery from waste represents an important way to reduce the amount of electric energy to be produced using fossil fuels, i.e. non-renewable sources of energy. Moreover, the energy recovery practice can present interesting economic revenues. Since, at the present time, a large amount of waste is disposed in landfills, it is clear how the use of end life products

Roberto Bove; Piero Lunghi

2006-01-01

187

Environmental Impacts of Solid Waste Landfilling  

Microsoft Academic Search

Inevitable consequences of the practice of solid waste disposal in landfills are gas and leachate generation due primarily to microbial decomposition, climatic conditions, refuse characteristics and landfilling operations. The migration of gas and leachate away from the landfill boundaries and their release into the surrounding environment present serious environmental concerns at both existing and new facilities. Besides potential health hazards,

Mutasem El-Fadel; Angelos N. Findikakis; James O. Leckie

1997-01-01

188

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

Microsoft Academic Search

Landfill leachates sampled during and after an accidental landfill fire were analysed and the levels of selected metals and chemical compounds compared to those occurring in the leachate under normal conditions. The fire at the landfill site was put out by excavation and cooling by use of water. The investigation during the fire and fire fight revealed a moderate increase

Joar Karsten Øygard; Amund Måge; Elin Gjengedal; Tore Svane

2005-01-01

189

Early changes in the fatty acid composition of photosynthetic membrane lipids from Populus nigra grown on a metallurgical landfill.  

PubMed

We compared the fatty acid composition of leaves taken from poplars on a metal-contaminated landfill, and on the uncontaminated roadside bordering this site. For the first time, it is shown that the percentage of linolenic acid, which is mainly associated with thylakoid lipids, was significantly lower in tree species within the landfill than within the control area. A correlation study was carried out to investigate relationships between the C18:3/(C18:0 + C18:1 + C18:2) fatty acid ratios and the metal contents in soils and leaves. Lead and chromium leaf contents were significantly negatively correlated to this fatty acid ratio. The impact of each of these metals remains difficult to evaluate, but chromium in leaf likely plays a major role in toxicity. In addition, the decrease in the C18:3/(C18:0 + C18:1 + C18:2) fatty acid ratio occurred at low leaf metal content, and therefore it is shown that this ratio can be used as an early indicator of the effect of metals. PMID:22531865

Le Guédard, Marina; Faure, Olivier; Bessoule, Jean-Jacques

2012-07-01

190

Dual Frequency Acoustic Gas Composition Analyzer.  

National Technical Information Service (NTIS)

The patent application describes an apparatus for determining the composition of a gas by measuring the acoustic impedence and absorption of a gas at two distinct frequencies. The velocity variations due to the presence of a gas in a fixed length column a...

J. E. Jacobs

1974-01-01

191

Measuring Water in Bioreactor Landfills  

NASA Astrophysics Data System (ADS)

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 was 29%, while the moisture content, the mass of water divided by total wet mass of solid waste, was 28%. Near the sloped sides of the landfill, PTT results indicated that only 7.1% of the pore space was filled with water, while the moisture content was estimated to be 6.9%. These measurements are in close agreement with gravimetric measurements made on solid waste samples collected after each PTT: moisture content of 27% in the center of the landfill and only 6% near the edge of the landfill. We discuss these measurements in detail, the limitations of the PTT method for landfills, and operational guidelines for achieving unbiased measurements of moisture content in landfills using the PTT method.

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

2004-12-01

192

Method for designing gas tag compositions  

DOEpatents

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.

Gross, K.C.

1995-04-11

193

Method for designing gas tag compositions  

DOEpatents

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.

Gross, Kenny C. (1433 Carriage La., Bolingbrook, IL 60440)

1995-01-01

194

OUTER LOOP LANDFILL CASE STUDY  

EPA Science Inventory

This presentation will describe the interim data reaulting from a CRADA between USEPA and Waste Management, Inc. at the outer Loop Landfill Bioreactor research project located in Louisville, KY. Recently updated data will be presented covering landfill solids, gas being collecte...

195

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...

196

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 ...

197

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

SciTech Connect

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 saturation). Based on the normalized parameters, predictive power-law models for D{sub p}({epsilon}/f) and k{sub a}({epsilon}/f) models were developed based on a single parameter (water blockage factor M for D{sub p} and P for k{sub a}). The water blockage factors, M and P, were found to be linearly correlated to {rho}{sub b} values, and the effects of dry bulk density on D{sub p} and k{sub a} for both '+gravel' and '-gravel' fractions were well accounted for by the new models.

Wickramarachchi, Praneeth, E-mail: praneeth1977@yahoo.co.uk [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Kawamoto, Ken; Hamamoto, Shoichiro [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Institute for Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Nagamori, Masanao [Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115 (Japan); Moldrup, Per [Environmental Engineering Section, Dept. of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 57, DK-9000 Aalborg (Denmark); Komatsu, Toshiko [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Institute for Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan)

2011-12-15

198

Barometric pressure and gas composition  

NASA Technical Reports Server (NTRS)

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.

Malkin, V. B.

1975-01-01

199

PAEs and BPA removal in landfill leachate with Fenton process and its relationship with leachate DOM composition  

Microsoft Academic Search

An increasing attention has been paid to the trace endocrine disrupting compounds (EDCs) in landfill leachate. In this paper, the removal of EDCs including phthalic acid esters (PAEs) and bisphenol A (BPA) from the fresh and mature landfill leachate by Fenton treatment was studied. More than 40% of PAEs and about 62% of BPA were removed from the raw mature

Pin-Jing He; Zhong Zheng; Hua Zhang; Li-Ming Shao; Qiong-Yao Tang

2009-01-01

200

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

201

Anammox: An option for ammonium removal in bioreactor landfills  

Microsoft Academic Search

Experiments carried out in bioreactor landfill simulators demonstrated that more than 40% of the total N was transferred into the liquid and gas phases during the incubation period of 380days. Ammonium, an end product of protein degradation and important parameter to consider during landfill closure, tends to accumulate up to inhibitory levels in the leachate of landfills especially in landfills

Roberto Valencia; Willem van der Zon; Hans Woelders; Henk J. Lubberding; Huub J. Gijzen

2011-01-01

202

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

PubMed

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

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

2014-05-01

203

Landfill mining: Giving garbage a second chance  

SciTech Connect

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

Cobb, C.C.; Ruckstuhl, K. (SPM Group, Inc., Preston, MN (USA))

1988-08-01

204

Biologically reactive multispecies transport in sanitary landfill  

SciTech Connect

This study proposes a numerical model for gas- and water-phase solute transport describing the change in leachate quality and gas production by microbial activities in a sanitary landfill. The proposed model includes gas and water flows, multispecies transport of gas and water phases, interphase mass transfer of solids and water-phase solutes, microbial growth and death, and aerobic and anaerobic biodegradation. In simulations of gas-phase flow and transport, the influence of gas temperature and composition on flow and transport phenomena area incorporated by changing the gas viscosity and diffusivity. Simulation results using the proposed model are very close to the results of the BIOF and T model and analytical solutions on test problems. Finally, the model is applied to simulate the leachate quality and three gas compositions of a waste decomposition experiment using a lysimeter. The results of the simulation explain the dynamic fluctuation of gas composition with time and match the leachate quality and three gas compositions measured in a limited time span.

Suk, H.; Lee, K.K.; Lee, C.H.

2000-05-01

205

MSW LANDFILL BIOREACTOR RESEARCH  

EPA Science Inventory

MSW bioreactors offer an innovative way of optimizing existing landfill volume by actively degrading the waste mass within a waste containment system. Bioreactor leachate, gas, and solids monitoring is part of a 5 year CRADA between US EPA and Waste Mgt., Inc. at the Outer Loop ...

206

Instrumentation for continuous monitoring of meteorological variables and soil gas pressure in landfill cover  

Microsoft Academic Search

To examine changes in soil gas pressure relative to changes in atmospheric pressure and other meteorological variables, weather station sensors and electronic pressure transducers were interfaced with an RCA COSMAC microcomputer. The microcomputer control permitted simultaneous acquisition of pressure and meteorological data on cassette tape. Because the RCA unit uses CMOS circuitry, it can be battery operated, and is therefore

C. Moore; M. Vogt; J. Bogner

1986-01-01

207

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

NASA Astrophysics Data System (ADS)

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 the heat generation in landfills may become controlling, Heat can be dissipated, but at energy and monetary cost. Increased waste liquid content, required for biological activity has been a concern. Offsetting risk is the accelerated treatment of many dissolved contaminants in landfill liquid with time. It has proven possible to manage liquid flows within environmental and regulatory constraints. There have been concerns about containment by chemosynthetic lining of leachate liquids draining from landfills. Yet molecular bonds of lining under anaerobic conditions could be expected to last for centuries (and in fact up to millenia). There is of course no landfill experience over millenia but analogous compounds of geologic relevance have shown very desirable long term stability. Two other areas being investigated are waste slope stability and the precipitation of carbonate salts The climate significance and geophysical issues with landfills will be discussed, and some experimental findings leading to conclusions will be reviewed

Augenstein, D.; Yazdani, R.

2002-12-01

208

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

Microsoft Academic Search

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

A.. Bockreis; I. Steinberg

2005-01-01

209

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

PubMed

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 ?g 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

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

2010-11-01

210

Venice Park landfill: Working with the community  

SciTech Connect

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

McAdams, C.L.

1993-09-01

211

Methane oxidation in a landfill cover with capillary barrier  

Microsoft Academic Search

The methane oxidation potential of a landfill cover with capillary barrier was investigated in an experimental plant (4.8m×0.8m×2.1m). The cover soil consisted of two layers, a mixture of compost plus sand (0.3m) over a layer of loamy sand (0.9m). Four different climatic conditions (summer, winter, spring and fall) were simulated. In and outgoing fluxes were measured. Gas composition, temperature, humidity,

J. Berger; L. V. Fornés; C. Ott; J. Jager; B. Wawra; U. Zanke

2005-01-01

212

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

PubMed

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

Assamoi, Bernadette; Lawryshyn, Yuri

2012-05-01

213

Methane emissions from MBT landfills.  

PubMed

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. It is therefore necessary to generate more data in the future in order to calculate more precise methane emission rates from MBT landfills. This is important for the overall calculation of the climate gas production in Germany which is required once a year by the German Government. PMID:23756351

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

2013-09-01

214

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

Microsoft Academic Search

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

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

2010-01-01

215

Landfills as a biorefinery to produce biomass and capture biogas.  

PubMed

While landfilling provides a simple and economic means of waste disposal, it causes environmental impacts including leachate generation and greenhouse gas (GHG) emissions. With the introduction of gas recovery systems, landfills provide a potential source of methane (CH4) as a fuel source. Increasingly revegetation is practiced on traditionally managed landfill sites to mitigate environmental degradation, which also provides a source of biomass for energy production. Combustion of landfill gas for energy production contributes to GHG emission reduction mainly by preventing the release of CH4 into the atmosphere. Biomass from landfill sites can be converted to bioenergy through various processes including pyrolysis, liquefaction and gasification. This review provides a comprehensive overview on the role of landfills as a biorefinery site by focusing on the potential volumes of CH4 and biomass produced from landfills, the various methods of biomass energy conversion, and the opportunities and limitations of energy capture from landfills. PMID:23069612

Bolan, N S; Thangarajan, R; Seshadri, B; Jena, U; Das, K C; Wang, H; Naidu, R

2013-05-01

216

Theory for a gas composition sensor based on acoustic properties  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

217

Direct determination of chlorophenols in landfill leachates by solid-phase micro-extraction–gas chromatography–mass spectrometry  

Microsoft Academic Search

Landfill leachates represent a serious environmental concern with regard to trace priority pollutants introduced into the aquatic environment. From the analytical point of view, they constitute complex matrices because of their high organic matter content and competition with the trace analytes in the extraction procedure. Although the use of SPME to extract chlorophenols in leachates has already been described in

A Ribeiro; M. H Neves; M. F Almeida; A Alves; L Santos

2002-01-01

218

Exhaust gas composition measurement. [liquid monopropellant rocket engine performance tests  

NASA Technical Reports Server (NTRS)

The design, installation, checkout, and operation of an exhaust gas composition measurement system for collecting and analyzing the exhaust gas from a liquid monopropellant rocket engine are described. Design guidelines are given for the critical components of each portion of the system to provide an exhaust gas composition measurement which meets the performance criteria specified.

1979-01-01

219

Tunable composite membranes for gas separations  

SciTech Connect

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.

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

1999-05-01

220

The effect of landfill leachate composition on organics and nitrogen removal in an activated sludge system with bentonite additive  

Microsoft Academic Search

A pre-denitrification activated sludge system (AS) without internal recycle was used in lab-scale studies of landfill leachate treatment. A bentonite supplement at a ratio of 1:4 (mineral : biomass) was used to ensure high sludge settling levels and to serve as a micro-organisms carrier. The system was operated within different parameters such as hydraulic retention time (HRT), ammonia loading rate

J. Wiszniowski; J. Surmacz-Górska; D. Robert; J.-V. Weber

2007-01-01

221

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

PubMed

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

López, Ana; Lobo, Amaya

2014-08-01

222

Landfill leachate treatment: Review and opportunity  

Microsoft Academic Search

In most countries, sanitary landfilling is nowadays the most common way to eliminate municipal solid wastes (MSW). In spite of many advantages, generation of heavily polluted leachates, presenting significant variations in both volumetric flow and chemical composition, constitutes a major drawback. Year after year, the recognition of landfill leachate impact on environment has forced authorities to fix more and more

S. Renou; J. G. Givaudan; S. Poulain; F. Dirassouyan; P. Moulin

2008-01-01

223

Greenhouse effect reduction and energy recovery from waste landfill  

Microsoft Academic Search

Waste management systems are a non-negligible source of greenhouse gases. In particular, methane and carbon dioxide emissions occur in landfills due to the breakdown of biodegradable carbon compounds operated on by anaerobic bacteria. The conventional possibilities of reducing the greenhouse effect (GHE) from waste landfilling consists in landfill gas (LFG) flaring or combustion with energy recovery in reciprocating engines. These

Lidia Lombardi; Ennio Carnevale; Andrea Corti

2006-01-01

224

Methane oxidation in simulated landfill cover soil environments  

SciTech Connect

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

Visscher, A. de; Thomas, D.; Boeckx, P.; Cleemput, O. van [Univ. of Ghent (Belgium)] [Univ. of Ghent (Belgium)

1999-06-01

225

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

NASA Astrophysics Data System (ADS)

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.

Hodson, E. L.; Prinn, R.

2005-12-01

226

Fluorescence excitation-emission matrix combined with regional integration analysis to characterize the composition and transformation of humic and fulvic acids from landfill at different stabilization stages.  

PubMed

Fluorescence excitation-emission matrix spectroscopy (EEMs) combined with fluorescence regional integration (FRI) analysis was used to investigate the composition and transformation of humic acid (HA) and fulvic acid (FA) from landfill. The EEMs of HAs at different landfill ages were characterized by two typical fluorescence chromophores with Ex/Em pairs at Ex=420-470 nm/Em=490-530 nm and Ex=345-375 nm/Em=450-465 nm. EEMs of FA were featured by other two distinctly different fluorophores with Ex/Em pairs at Ex=315-335 nm/Em=420-440 nm and Ex=255-275 nm/Em=425-455 nm. The results show that HA extracted from the refuse disposed in the year of 1989 was formed by connecting small-condensed aromatic structures with protein-like chains. Compared with HA extracted from the refuse disposed in the year of 1992, HA extracted from the refuse of 1996 had a higher fluorescence intensity and lower r(()(B)(,)(A)()) (the ratio of the fluorescence intensities of peak B and peak A) value. It contained low molar mass components, low aromatic condensation degree, and more easily oxidized substituents. This indicates that the landfill time strongly affects the EEMs characteristics of HA, and that the humification degree of HA increases with the landfill time. A red shift to a longer wavelength region and an increase of fluorescence intensity were observed when the concentration of HA was increased, suggesting that concentration had a great influence on the fluorescence characteristics of HAs. pH (2-12) also had significant effects on the fluorescence intensity, although it exerted no effect on the peak position of fluorescence of HA and FA. The results of FRI show that increasing concentration lead to more interactions among various structure components and that small molecular weight units tend to aggregate or be masked into more complicated and larger structures. The pH influence on the fluorescence intensity of HA seems mainly through molecular configuration, while the fluorescence intensity change with pH may be due to various substituents of FA. PMID:22104617

Xiaoli, Chai; Guixiang, Liu; Xin, Zhao; Yongxia, Hao; Youcai, Zhao

2012-03-01

227

Method and composition for generating nitrogen gas  

SciTech Connect

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.

Pietz, J.F.

1988-01-26

228

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

PubMed

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

Bergersen, Ove; Haarstad, Ketil

2008-08-01

229

Comparative Landfills  

NSDL National Science Digital Library

This lesson plan from ATEEC will explain solid and hazardous waste management. The activity would be most appropriate for technology studies or high school science classes. In all, it would require about two hours of class time, plus a few minutes a day for several weeks. The purpose of the lesson is to demonstrate what happens to garbage in landfills, and compare it to the process of burying trash. The activity is explained in depth in this lesson plan handout. The lesson plan is available for download as a PDF; users must create a free, quick login with ATEEC to access the materials.

Wishart, Ray

2013-06-19

230

Attenuation of landfill leachate at two uncontrolled landfills  

Microsoft Academic Search

Attenuation characteristics of landfill leachate were examined for two uncontrolled landfills in Korea. The two landfills containing municipal wastes without appropriate bottom liner and leachate treatment system have different landfill age, waste volume, and most importantly different hydrogeologic settings. One landfill (Cheonan landfill) is situated in an open flat area while the other (Wonju landfill) is located in a valley.

Jin-Yong Lee; Jeong-Yong Cheon; Hyung-Pyo Kwon; Hee-Sung Yoon; Seong-Sun Lee; Jong-Ho Kim; Joung-Ku Park; Chang-Gyun Kim

2006-01-01

231

Characteristics of landfill leachates and alternatives for their treatment: A review  

Microsoft Academic Search

Sanitary landfilling is the most common way to eliminate solid urban wastes. An important problem associated to landfills is the production of leachates. The factors determining the characteristics of leachates from solid urban waste landfills are reviewed together with the reported compositions of leachates from various countries and origins. New data obtained from two landfills of different age in the

J. M. Lema; R. Mendez; R. Blazquez

1988-01-01

232

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

Microsoft Academic Search

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

M. Mwiganga; F. Kansiime

2005-01-01

233

The effects of daily cover soils on shear strength of municipal solid waste in bioreactor landfills  

Microsoft Academic Search

Bioreactor landfills are operated to enhance refuse decomposition, gas production, and waste stabilization. The major aspect of bioreactor landfill operation is the recirculation of collected leachate back through the refuse mass. Due to the accelerated decomposition and settlement of solid waste, bioreactor landfills are gaining popularity as an alternative to the conventional landfill. The addition or recirculation of leachate to

Mohamed A. Haque

2009-01-01

234

Geochemical processes in landfills  

NASA Astrophysics Data System (ADS)

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

Förstner, Ulrich; Kersten, Michael; Wienberg, Reinhard

235

Methane oxidation at a surface-sealed boreal landfill  

Microsoft Academic Search

Methane oxidation was studied at a closed boreal landfill (area 3.9ha, amount of deposited waste 200,000 tonnes) equipped with a passive gas collection and distribution system and a methane oxidative top soil cover integrated in a European Union landfill directive-compliant, multilayer final cover. Gas wells and distribution pipes with valves were installed to direct landfill gas through the water impermeable

Juha Einola; Kai Sormunen; Anssi Lensu; Antti Leiskallio; Matti Ettala; Jukka Rintala

2009-01-01

236

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

PubMed

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 ?(13)C, ?(2)H and ?(18)O of different leachates from lab-scale experiments, lysimeter experiments and a landfill under in situ aeration. In the laboratory, columns filled with MSW of different age and reactivity were percolated under aerobic and anaerobic conditions. In landfill simulation reactors, waste of a 25year old landfill was kept under aerobic and anaerobic conditions. The lysimeter facility was filled with mechanically shredded fresh waste. After starting of the methane production the waste in the lysimeter containments was aerated in situ. Leachate and gas composition were monitored continuously. In addition the seepage water of an old landfill was collected and analysed periodically before and during an in situ aeration. We found significant differences in the ?(13)C-value of the dissolved inorganic carbon (?(13)C-DIC) of the leachate between aerobic and anaerobic waste material. During aerobic degradation, the signature of ?(13)C-DIC was mainly dependent on the isotopic composition of the organic matter in the waste, resulting in a ?(13)C-DIC of -20‰ to -25‰. The production of methane under anaerobic conditions caused an increase in ?(13)C-DIC up to values of +10‰ and higher depending on the actual reactivity of the MSW. During aeration of a landfill the aerobic degradation of the remaining organic matter caused a decrease to a ?(13)C-DIC of about -20‰. Therefore carbon isotope analysis in leachates and groundwater can be used for tracing the oxidation-reduction status of MSW landfills. Our results indicate that monitoring of stable isotopic signatures of landfill leachates over a longer time period (e.g. during in situ aeration) is a powerful and cost-effective tool for characterising the biodegradability and stability of the organic matter in landfilled municipal solid waste and can be used for monitoring the progress of in situ aeration. PMID:23540355

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

2013-10-01

237

Tunable Composite Membranes for Gas Separations.  

SciTech Connect

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).

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

1997-07-01

238

Landfill sites, botulism and gulls.  

PubMed Central

Botulism due to Clostridium botulinum type C causes considerable mortality in gulls in the UK, and refuse disposal sites are suspected as a major source of toxin. C. botulinum types B, C and D were each found in 12 (63.2%) of 19 landfill sites examined. Type E was detected in only one (5.2%) and types A, F and G were not found. The prevalence of type C spores was much higher than that demonstrated in the UK environment by earlier surveys. The presence of these spores, together with the rotting organic matter and generated heat associated with landfill sites, undoubtedly leads to bacterial proliferation and toxigenesis. This is likely to result in botulism in scavenging gulls unless skilled landfill management prevents the ingestion of toxic material. Type D spores were previously shown to be rare in the UK environment and their high prevalence on landfill sites was therefore surprising. Four composite samples of refuse collected before distribution on a landfill gave negative results for C. botulinum and it seems likely that the gulls themselves play a major role in introducing contamination.

Ortiz, N. E.; Smith, G. R.

1994-01-01

239

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

PubMed

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

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

2011-12-01

240

Field application of nitrogen and phenylacetylene to mitigate greenhouse gas emissions from landfill cover soils: effects on microbial community structure.  

PubMed

Landfills are large sources of CH(4), but a considerable amount of CH(4) can be removed in situ by methanotrophs if their activity can be stimulated through the addition of nitrogen. Nitrogen can, however, lead to increased N(2)O production. To examine the effects of nitrogen and a selective inhibitor on CH(4) oxidation and N(2)O production in situ, 0.5 M of NH(4)Cl and 0.25 M of KNO(3), with and without 0.01% (w/v) phenylacetylene, were applied to test plots at a landfill in Kalamazoo, MI from 2007 November to 2009 July. Nitrogen amendments stimulated N(2)O production but had no effect on CH(4) oxidation. The addition of phenylacetylene stimulated CH(4) oxidation while reducing N(2)O production. Methanotrophs possessing particulate methane monooxygenase and archaeal ammonia-oxidizers (AOAs) were abundant. The addition of nitrogen reduced methanotrophic diversity, particularly for type I methanotrophs. The simultaneous addition of phenylacetylene increased methanotrophic diversity and the presence of type I methanotrophs. Clone libraries of the archaeal amoA gene showed that the addition of nitrogen increased AOAs affiliated with Crenarchaeal group 1.1b, while they decreased with the simultaneous addition of phenylacetylene. These results suggest that the addition of phenylacetylene with nitrogen reduces N(2)O production by selectively inhibiting AOAs and/or type II methanotrophs. PMID:20809077

Im, Jeongdae; Lee, Sung-Woo; Bodrossy, Levente; Barcelona, Michael J; Semrau, Jeremy D

2011-01-01

241

Landfilling of waste: accounting of greenhouse gases and global warming contributions  

Microsoft Academic Search

Accounting of greenhouse gas (GHG) emissions from waste landfilling is summarized with the focus on processes and technical data for a number of different landfilling technologies: open dump (which was included as the worst-case-scenario), conven- tional landfills with flares and with energy recovery, and landfills receiving low-organic-carbon waste. The results showed that direct emissions of GHG from the landfill systems

Simone Manfredi; Davide Tonini; Thomas H. Christensen; H. Scharff

2009-01-01

242

Ground penetrating radar characterization of a landfill  

NASA Astrophysics Data System (ADS)

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.

Yochim, April Theresa

243

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

PubMed

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. PMID:22342185

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

2012-03-23

244

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

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.

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

2012-01-01

245

Degradability of Chlorinated Solvents in Landfill Environment  

NASA Astrophysics Data System (ADS)

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 methane production, were monitored throughout the refuse decomposition process. At two different stages of refuse decomposition, active refuse decomposition representing young landfills and maturation phase representing aged landfills, anaerobic microbial cultures were derived from selected bioreactors and tested in serum bottles for their abilities to biodegrade target CAHs. Complementary to the bioreactor experiment, the serum bottle experiment was designed to investigate specific conditions that potentially control or limit the reductive dechlorination of CAHs in landfills. The conditions tested include 1) inhibited refuse methanogenesis, 2) enhanced methanogenic refuse decomposition, 3) presence of other organic carbons commonly found in landfills such as cellulose, lactate, ethanol, and acetate and 4) presence of yeast extract and humic acids which are commonly found in aged landfills. This research investigated the degradability, the degradation rate, and the extent of dechlorination of CAHs in a landfill ecosystem as the refuse decomposition progresses. The results can lead to a broader application of the intrinsic bioattenuation capacity of landfills. An in situ remedial strategy directly tackling the contaminant source can minimize the risk of future impact and achieve a significant saving in remediation cost. The information of contaminant fate in landfills can also help regulatory agencies formulate risk-based guidelines for post-closure monitoring programs and potential re-development projects.

Wang, J. Y.; Litman, M.

2002-12-01

246

Sanitary Landfill. A Bibliography.  

National Technical Information Service (NTIS)

A bibliography on sanitary landfills is presented for the period 1925 - 1968, covering such materials as garbage and refuse disposal, ground water contamination, loading and structural properties, urban and rural sites, landfill internal mechanics, collec...

R. L. Steiner R. Kantz

1968-01-01

247

Development of a perimeter odor monitoring system for landfill sites  

Microsoft Academic Search

A need exists for instrumentation capable of continuous measurement of gas and odor emission from the perimeter of a landfill site. Current practice is to manually use a flame ionization detector. Instruments based on an array of MOS gas sensors were developed and placed on the perimeter of a landfill site, functioning as point monitoring systems, using methane as a

Krishna C. Persaud; N. C. P. Woodyatt; R. W. Sneath

2008-01-01

248

Exopolysaccharide control of methane oxidation in landfill cover soil  

Microsoft Academic Search

The study objective was to examine whether a relationship exists between the accumulation of exopolymeric substances (EPS) in landfill cover soil and the gradual decline in biotic methane oxidation observed in laboratory soil columns sparged with synthetic landfill gas. A mathematical model that combined multicomponent gas diffusion along the vertical axis of the columns with biotic methane oxidation was used

Helene A. Hilger; Sarah K. Liehr; Morton A. Barlaz

1999-01-01

249

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)

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.

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

1998-10-01

250

Subsidence performance of landfills  

Microsoft Academic Search

This paper presents field measurements of landfill subsidence for five municipal solid waste landfills. Data from the.five sites are within the range of landfill subsidence reported in other publications.At one site with variable subsidence of up to 10 percent of the landfill height in 3 years after capping, portions of an in-situ HDPE cap geomembrane were uncovered. The geomembrane showed

Daniel R. Spikula

1997-01-01

251

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

Microsoft Academic Search

Landfill gas is a product of the natural biological decomposition of organic material contained in wastes deposited in landfills. This denomination generically indicates a gas mixture made of methane and carbon dioxide. These gases are produced until most of the organic material in the waste has been degraded. Emissions from municipal landfill sites are therefore potentially harmful to both local

Michela Maione; Jgor Arduini; Matteo Rinaldi; Filippo Mangani; Bruno Capaccioni

2005-01-01

252

2-Liter Landfill  

NSDL National Science Digital Library

In this activity, learners gain a better understanding of how household/school waste breaks down in a landfill. Learners collect trash and then create miniature landfills in 2-liter bottles. Learners record observations about their landfills at least once a week for a month. This activity is part of a larger curriculum related to amphibians and conservation.

Aquarium, Omaha'S H.

2009-01-01

253

The effect of landfill leachate composition on organics and nitrogen removal in an activated sludge system with bentonite additive.  

PubMed

A pre-denitrification activated sludge system (AS) without internal recycle was used in lab-scale studies of landfill leachate treatment. A bentonite supplement at a ratio of 1:4 (mineral : biomass) was used to ensure high sludge settling levels and to serve as a micro-organisms carrier. The system was operated within different parameters such as hydraulic retention time (HRT), ammonia loading rate (ALR) or external recycle ratio, which was adapted to treat varying leachate concentrations of COD and ammonia, ranging from 1020 to 2680 mgO(2)l(-1) and 400-890 mgNH(4)-Nl(-1) respectively. The nitrification was complete and ammonia oxidation reached 99%; this was obtained while the ALR did not exceed 0.09 g NH(4)(+)-Ng(-1)MLVSS d(-1) and HRT was not lower than 1 day (in the aeration reactor). The performance of denitrification was successfully improved by controlling the external recycle rate, when the BOD(5)/N ratio in the raw leachate was 4.1. Consequently, N-removal of up to 80% was achieved. A 10-fold decrease in the denitrification rate was obtained at a BOD(5)/N ratio of 0.5. The efficiency of COD removal varied significantly from 36% to 84%. The positive effect of bentonite addition was determined and is discussed based on preliminary studies. The experiments were carried out in fill-and-draw activated sludge with bentonite; the biomass ratio was 1:2. The activated sludge with bentonite was fed with a synthetic high ammonia and organic-free medium. PMID:17030402

Wiszniowski, J; Surmacz-Górska, J; Robert, D; Weber, J-V

2007-10-01

254

Effect of Biogas Generation on Radon Emissions from Landfills Receiving Radium-Bearing Waste from Shale Gas Development  

Microsoft Academic Search

Dramatic increases in the development of oil and natural gas from shale formations will result in large quantities of drill cuttings, flowback water, and produced water. These organic-rich shale gas formations often contain elevated concentrations of naturally occurring radioactive materials (NORM), such as uranium, thorium, and radium. Production of oil and gas from these formations will also lead to the

Gary R. Walter; Roland R. Benke; David A. Pickett

2012-01-01

255

Landfills in New York City: 1844--1994  

SciTech Connect

Historic topographic maps are reviewed to locate landfills constructed within New York City during four time intervals between 1844 and 1994. A total of 184.75 km{sup 2} (45,650 acres) of landfill are identified (approximately 20% of the study area). Data are not available to determine the fill composition at most sites but literature sources indicate that municipal solid waste (MSW) has been an important source of fill since at least 1891. Qualitative temporal trends in the spatial distribution of landfills and the composition and thickness of MSW landfills are observed. The oldest landfills are clustered in the vicinity of the early urban center (southern New York County) but expand in spatial distribution after the turn of this century. Logs of borings through 10 MSW landfills show that waste landfills built prior to the mid-1950s contain abundant ash (coal ash is common in the oldest landfills) and are relatively thin (3--7 m) with no topographic mounding. In MSW landfills built since that time, uncombusted organic matter is abundant, thicknesses increase greatly (16--27 m), and pronounced topographic mounding is observed. Most landfills identified in this study were built on tidal wetlands. Fine-grained wetland deposits underlying the landfills and close proximity to large surface-water bodies favor lateral transport of leachate from MSW landfills in shallow ground water and local discharge to surface water. The wide distribution of historic landfills and common use of MSW for fill indicates that these sites should be considered in investigations of ground water, surface water, and sediment quality in New York City and other urban areas where extensive historic landfilling has occurred.

Walsh, D.C. [NYSDEC, Long Island City, NY (United States); LaFleur, R.G. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Earth and Environmental Sciences

1995-07-01

256

Characterization of ceramic composite materials for gas turbine applications  

Microsoft Academic Search

Ceramic composite materials have the capability to sustain high stress in the presence of high temperatures and aggressive atmospheres. Such materials are being considered for application as cumbustors, burner cubes, heat exchangers, headers. hot-gas filters, and even rotors of stationary gas turbine engines. In the present program, Nicalon preforms of tubular geometry were fabricated with different fiber architectures (filament winding,

K. Reifsnider; W. Stinchcomb; K. Liao; L. Oleksuk; D. Stinton

1993-01-01

257

Bisphenol A in hazardous waste landfill leachates  

Microsoft Academic Search

The levels of bisphenol A in hazardous waste landfill leachates collected in Japan in 1996 were determined by gas chromatograph\\/mass spectrometer (GC\\/MS). Bisphenol A was found in seven of 10 sites investigated. All the hazardous waste landfills with leachates contaminated by bisphenol A were controlled. The concentrations of bisphenol A ranged from 1.3 to 17,200 ?g\\/l with a median concentration

Takashi Yamamoto; Akio Yasuhara; Hiroaki Shiraishi; Osami Nakasugi

2001-01-01

258

Methane Oxidation in Landfill Cover Soil  

Microsoft Academic Search

Methane oxidation in the cover soil of the Khmet'evo municipal landfill in Moscow oblast was investigated. Methane emission from the experimental site of the landfill was highly heterogeneous. At a depth of 45–60 cm, the pore gas mainly consisted of CH4 (60–70%) and CO2 (30–40%). In the upper layers of the cover soil, the concentration of these gases sharply decreased.

A. Yu. Kallistova; M. V. Kevbrina; V. K. Nekrasova; M. V. Glagolev; M. I. Serebryanaya; A. N. Nozhevnikova

2005-01-01

259

Determination of the Hydraulic Conductivity of the Alachua County Southwest Landfill.  

National Technical Information Service (NTIS)

Slug tests were conducted in the existing gas vents of the municipal landfill of Alachua County, Florida, for the purpose of determining the hydraulic conductivity of the landfilled municipal solid waste. The Bouwer and Rice method of analysis was applied...

K. L. Shank

1993-01-01

260

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

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.

Michalzik, B. [Institute of Geography, Georg-August University Goettingen, Unit of Landscape Ecology, Goldschmidtstrasse 5, 37073 Goettingen (Germany)], E-mail: bmichal@gwdg.de; Ilgen, G.; Hertel, F. [Bayreuth Institute of Terrestrial Ecosystem Research (BITOEK/BayCEER), Central Laboratory Unit, University of Bayreuth, Dr. Hans- Frisch-Strasse 1-3, 95448 Bayreuth (Germany); Hantsch, S.; Bilitewski, B. [Institute for Waste Management and Contaminated Site Treatment, Dresden University of Technology, Pratzschwitzer Strasse 15, 01796 Pirna (Germany)

2007-07-01

261

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

SciTech Connect

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.

Kirkeby, Janus T.; Birgisdottir, Harpa [Environment and Resources, Technical University of Denmark, DTU, Building 113, DK-2800 Kgs. Lyngby (Denmark); Bhander, Gurbakash Singh; Hauschild, Michael [Department of Manufacturing Engineering and Management, Technical University of Denmark, Building 424, DK-2800 Lyngby (Denmark); Christensen, Thomas H. [Environment and Resources, Technical University of Denmark, DTU, Building 113, DK-2800 Kgs. Lyngby (Denmark)], E-mail: thc@er.dtu.dk

2007-07-01

262

Gas composition sensing using carbon nanotube arrays  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

263

COMPOSITION OF LOW-REDSHIFT HALO GAS  

SciTech Connect

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.

Cen Renyue, E-mail: cen@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States)

2013-06-20

264

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

SciTech Connect

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, dispersion coefficients of Cu, ranging from 3.47 x 10{sup -6} m{sup 2}/s to 5.37 x 10{sup -2} m{sup 2}/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 x 10{sup -10} m{sup 2}/s, 5.37 x 10{sup -10} m{sup 2}/s, 2.69 x 10{sup -10} m{sup 2}/s and 3.29 x 10{sup -10} m{sup 2}/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 is believed to be prevented with the use of zeolite and bentonite materials in landfill liner systems.

Varank, Gamze, E-mail: gvarank@yildiz.edu.tr [Yildiz Technical University, Faculty of Civil Engineering, Department of Environmental Engineering, 34220 Davutpasa, Esenler, Istanbul (Turkey); Demir, Ahmet, E-mail: ahmetd@yildiz.edu.tr [Yildiz Technical University, Faculty of Civil Engineering, Department of Environmental Engineering, 34220 Davutpasa, Esenler, Istanbul (Turkey); Yetilmezsoy, Kaan, E-mail: yetilmez@yildiz.edu.tr [Yildiz Technical University, Faculty of Civil Engineering, Department of Environmental Engineering, 34220 Davutpasa, Esenler, Istanbul (Turkey); Bilgili, M. Sinan, E-mail: mbilgili@yildiz.edu.tr [Yildiz Technical University, Faculty of Civil Engineering, Department of Environmental Engineering, 34220 Davutpasa, Esenler, Istanbul (Turkey); Top, Selin, E-mail: stop@yildiz.edu.tr [Yildiz Technical University, Faculty of Civil Engineering, Department of Environmental Engineering, 34220 Davutpasa, Esenler, Istanbul (Turkey); Sekman, Elif, E-mail: esekman@yildiz.edu.tr [Yildiz Technical University, Faculty of Civil Engineering, Department of Environmental Engineering, 34220 Davutpasa, Esenler, Istanbul (Turkey)

2011-11-15

265

Structure and Composition Analysis of Natural Gas Hydrates: 13C NMR Spectroscopic and Gas Uptake Measurements of Mixed Gas Hydrates  

Microsoft Academic Search

Gas hydrates are becoming an attractive way of storing and transporting large quantities of natural gas, although there has been little effort to understand the preferential occupation of heavy hydrocarbon molecules in hydrate cages. In this work, we present the formation kinetics of mixed hydrate based on a gas uptake measurement during hydrate formation, and how the compositions of the

Yutaek Seo; Seong-Pil Kang; Wonho Jang

2009-01-01

266

Controls on coal-bed gas composition  

Microsoft Academic Search

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

1993-01-01

267

Environmental problems associated with the development and operation of a lined and unlined landfill site: a case study demonstrating two landfill sites in Patra, Greece  

Microsoft Academic Search

The present work demonstrates the environmental problems associated with the development and operation of a lined and unlined\\u000a landfill site, both used for municipal solid waste landfilling, that are situated next to the city of Patra, Greece. Findings\\u000a from a detailed site investigation as well calculations on hydrologic evaluation of landfill’s performance and measurements\\u000a on leachate composition proved that the

Nikos Depountis; George Koukis; Nikos Sabatakakis

2009-01-01

268

Composition for removing sulfides from industrial gas  

Microsoft Academic Search

This patent describes a liquid sorbent solution useful for selectively removing a sulfide from a moist or dry gas stream which comprises: (a) a substantially non-aqueous inert liquid solvent; (b) at least 0.1 weight percent, based on the solvent, of an aromatic nitrile containing an electron-attracting substituent on the aromatic ring, the substituent having an attraction for electrons which is

R. Starkston; M. C. Luce; R. V. Homsy

1987-01-01

269

Composition dependence of ion-transport coefficients in gas mixtures  

NASA Technical Reports Server (NTRS)

Simple momentum-transfer theory for the composition dependence of ion mobilities and diffusion coefficients in gas mixtures at arbitrary field strengths is corrected and extended, and compared with a similar theory based on momentum and energy transfer, and with results based on direct solution of the Boltzmann equation by Kihara's method. Final equations are recommended for predicting composition dependences, given only results on ion mobilities and diffusion coefficients in the pure component gases.

Whealton, J. H.; Mason, E. A.; Robson, R. E.

1974-01-01

270

Composition dependence of ion transport coefficients in gas mixtures  

NASA Technical Reports Server (NTRS)

A simple momentum-transfer theory for the composition dependence of ion mobilities and diffusion coefficients in gas mixtures at arbitrary field strengths is corrected, extended, and compared with a similar theory based on momentum and energy transfer, and with results based on direct solution of the Boltzmann equation by Kihara's method. Final equations are recommended for predicting composition dependences, given only results on ion mobilities and diffusion coefficients in the pure component gases.

Whealton, J. H.; Mason, E. A.; Robson, R. E.

1973-01-01

271

Impact Damage in Sandwich Composite Structures From Gas Gun Tests  

Microsoft Academic Search

The paper studies the High Velocity Impact (HVI) response of aircraft structures by means of gas gun impact tests and post-test\\u000a NDE evaluation. The scope of the activity comprises structural components such as stringer stiffened composite panels and\\u000a a range of composite sandwich structures, with projectiles such as ice, synthetic birds, runway debris and tyre\\/rim debris.\\u000a The tests and simulations

Nathalie Toso-Pentecote; Alastair Johnson

272

Leachate evaporation demonstration project at Brookhaven Municipal Landfill. Final report  

SciTech Connect

A demonstration leachate evaporation project using landfill gas as the primary energy source was successfully conducted at the Brookhaven Municipal Landfill. A submerged flame evaporator was used for the process. Leachate generated at the landfill could be concentrated to greater than 25% total solids. At the highest level of solids achieved, the evaporation equipment continued to meet design capacity. Effluent produced in the process passed the United States Environmental Protection Agency`s Toxicity Characteristics Leaching Procedure (TCLP). In addition, effluent was virtually odor-free. Based on these results, according to applicable permits for the project, the effluent material could be returned directly to the landfill.

NONE

1998-09-01

273

Stabilized landfill leachate treatment by combined physicochemical–nanofiltration processes  

Microsoft Academic Search

Landfill leachate is a complex wastewater which the composition and concentration of contaminants are influenced by the type of waste deposited and the age of landfill. In the last years, several processes or process combinations were developed and tested to reach requirements for the discharge of leachate. Among the new processes, membrane processes are considered as promising: reverse osmosis is

D Trebouet; J. P Schlumpf; P Jaouen; F Quemeneur

2001-01-01

274

LANDFILLS EFFLUENT LIMITATIONS GUIDELINES DATABASE  

EPA Science Inventory

Resource Purpose: This resource served as the main information source for national characteristics of landfills for the landfills effluent guidelines. The database was developed based on responses to the "1994 Waste Treatment Industry Questionnaire: Phase II Landfills" and...

275

Influence of Physical Parameters on Methane Oxidation in Landfill Cover Soils  

Microsoft Academic Search

Methane emissions from landfills make an important contribution to the anthropogenic induced global warming, and it has been estimated that landfills are responsible for a major part of anthropogenic methane emission. Landfill cover soils are identified to have a huge potential for methane oxidation trough methanotrophs. There are several research efforts to investigate the optimum composition of cover soil to

Katherine Gómez

276

Modelling the biochemical degradation of solid waste in landfills  

Microsoft Academic Search

This paper describes the concept of a generic spatially distributed numerical model that has been developed to contain and link sub-models of landfill processes in order to simulate solid waste degradation and gas generation in landfills. The model includes the simulation of the transport of leachate and gases, and the consolidation of the solid waste. The structure of the model

Jim White; John Robinson; Qingchao Ren

2004-01-01

277

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...

278

Bioassays for the Evaluation of Landfill Leachate Toxicity  

Microsoft Academic Search

This article reviews the application of bioassays for assessing the toxicity hazard posed by landfill leachate discharged to an aquatic environment. Landfill leachate is a complex mixture of chemicals; thus it is difficult to assess the risk posed to aquatic wildlife using standard chemical identification techniques, such as gas chromatography–mass spectroscopy (GC-MS). From this review it is clear that toxicity

David John Lawrence Thomas; Sean Ferguson Tyrrel; Richard Smith; Steve Farrow

2009-01-01

279

Methane oxidation in simulated landfill cover soil environments  

Microsoft Academic Search

Methane is an important greenhouse gas. Its contribution to the enhanced global warming is estimated at 12%. A considerable fraction of the methane that is produced by landfills is oxidized by its covering soil before it can reach the atmosphere. This process was studied in soil columns that simulate landfill cover soil environments. The methane uptake was followed as a

Alex De Visscher; Dirk Thomas; Pascal Boeckx; Oswald Van Cleemput

1999-01-01

280

Quantifying the effect of oxidation on landfill methane emissions  

Microsoft Academic Search

Field, laboratory, and computer modeling methods were utilized to quantitatively assess the capability of aerobic microorganisms to oxidize landfill-derived methane (CH4) in cover soils. The investigated municipal landfill, located in Nashua, New Hampshire, was operating without gas controls of any type at the time of sample collection. Soil samples from locations of CH 4 flux to the atmosphere were returned

P. M. Czepiel; B. Mosher; P. M. Crill; R. C. Harriss

1996-01-01

281

Aerobic landfill bioreactor  

DOEpatents

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.

Hudgins, Mark P (Aiken, SC); Bessette, Bernard J (Aiken, SC); March, John C (Winterville, GA); McComb, Scott T. (Andersonville, SC)

2002-01-01

282

Aerobic landfill bioreactor  

DOEpatents

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.

Hudgins, Mark P (Aiken, SC); Bessette, Bernard J (Aiken, SC); March, John (Winterville, GA); McComb, Scott T. (Andersonville, SC)

2000-01-01

283

Landfill disposal systems  

PubMed Central

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 inspections and any repairs can be made without disturbing the waste. The surface seal landfill does not employ a subsurface barrier. The surface seal landfill successfully addresses each of the four environmental problems listed above, provided that this landfill design is utilized for dry wastes only and is located at a site which provides protection from groundwater and temporary perched water tables. ImagesFIGURE 3.FIGURE 4.FIGURE 7.FIGURE 7.

Slimak, Karen M.

1978-01-01

284

Report: management problems of solid waste landfills in Kuwait.  

PubMed

This paper evaluates current operational practices in municipal solid waste landfills in Kuwait to provide existing knowledge on uncontrolled landfilling and associated problems of solid waste disposal in developing countries. The current landfilling practices are safe neither for humans nor for the environment. The landfill sites receive all kinds of wastes such as food wastes, oil products, debris, dead animals, agricultural wastes, chemical wastes, wastewater and sewage sludge. The wastes are dumped, spread and compacted in an uncontrolled manner and cover material is not applied regularly. Dust created within the landfill site and gas emissions cause a public nuisance. The characteristics of leachate formed indicate high organic content and presence of heavy metals, salts and nutrients. There are no provisions for leachate or landfill gas collection at the landfill sites. Recommendations for adjustment in landfill operation have been made in recognition of the transition period that is experienced in proceeding from the past and present to the future management of landfills in Kuwait to safeguard the public health and protect the environment. PMID:12363092

Al-Yaqout, Anwar F; Hamoda, Mohamed F

2002-08-01

285

Biodegradation of Organic Matters from Mixed Unshredded Municipal Solid Waste through Air Convection before Landfilling  

Microsoft Academic Search

Landfilling is a dominant municipal solid waste (MSW) disposal method in most developing countries. In China, ?85% of the generated MSW is being disposed of in the landfills. The amount of MSW is growing rapidly with the rate of ?8–10% annually, which contains a high quantity of moisture and organic matters. The problems of leachate treatment and landfill gas (LFG)

Rasool B. Mahar; Jianguo Liu; Dongbei Yue; Yongfeng Nie

2007-01-01

286

Investigation of influence of lapes landfill leachate on ground and surface water pollution with heavy metals  

Microsoft Academic Search

As a result of global and intense production the waste disposal problems become more and more urgent. Waste processing, utilization and recycling is to a certain extent limited by many economic, organisational and technological factors, and this inevitably encourages waste disposal in landfills. Physical, chemical and biological interactions in landfill cell result in formation of landfill gas and harmful leachate.

Bronius Jaskelevi?ius; Vaida Lynikiene

2009-01-01

287

T2LBM Version 1.0: Landfill bioreactor model for TOUGH2  

Microsoft Academic Search

The need to control gas and leachate production and minimize refuse volume in landfills has motivated the development of landfill simulation models that can be used by operators to predict and design optimal treatment processes. T2LBM is a module for the TOUGH2 simulator that implements a Landfill Bioreactor Model to provide simulation capability for the processes of aerobic or anaerobic

Curtis M

2001-01-01

288

Landfill Bioreactor Performance: Second Interim Report Outer Loop Recycling and Disposal Facility, Louisville, Kentucky.  

National Technical Information Service (NTIS)

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...

2006-01-01

289

Tunable Composite Membranes for Gas Separations.  

SciTech Connect

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.

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

1997-10-01

290

TUNABLE COMPOSITE MEMBRANES FOR GAS SEPARATIONS  

SciTech Connect

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.

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

1999-01-01

291

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

Microsoft Academic Search

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.

2000-01-01

292

Characterization of ceramic composite membrane filters for hot gas cleaning  

Microsoft Academic Search

Novel composite ceramic membrane filters suitable for hot gas cleaning operations have been prepared from fly ash and titania particles on stainless steel woven mesh substrates. Both membranes had a structure like a solid packed bed with a thickness of less than 100 ?m. In the domain of laminar flow, significant differences in the pressure drop between experimental results and

Y. M. Jo; R. B. Hutchison; J. A. Raper

1997-01-01

293

Environmental applications using graphene composites: water remediation and gas adsorption  

NASA Astrophysics Data System (ADS)

This review deals with wide-ranging environmental studies of graphene-based materials on the adsorption of hazardous materials and photocatalytic degradation of pollutants for water remediation and the physisorption, chemisorption, reactive adsorption, and separation for gas storage. The environmental and biological toxicity of graphene, which is an important issue if graphene composites are to be applied in environmental remediation, is also addressed.

Kemp, K. Christian; Seema, Humaira; Saleh, Muhammad; Le, Nhien H.; Mahesh, Kandula; Chandra, Vimlesh; Kim, Kwang S.

2013-03-01

294

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

NASA Astrophysics Data System (ADS)

The 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 temperatures. 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. We report here the isotopic composition of catalytic gas generated from crude oil and pure hydrocarbons between 150 and 200°C. ? 13C for C 1 through C 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 -51.87‰ (oil = -22.5‰), progressed to a final composition of -26.94‰, similar to the maturity trend seen in natural gases: -50‰ to -20‰. 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.

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

1999-04-01

295

Sanitary Landfill Location Study.  

National Technical Information Service (NTIS)

Analysis and recommendations are given for the number, type, size and location of a county-owned and operated sanitary landfill for Stark County, Ohio. Twenty-seven strip mine sites were analyzed as to their suitability for a sanitary landfill. Twelve of ...

1969-01-01

296

Bioreactor Landfill Demonstration Project  

NSDL National Science Digital Library

Managed by the Florida Center for Solid and Hazardous Waste Management, this Website provides information on the Bioreactor Landfill Demonstration Project. The slow decomposition rates in current municipal landfills have prompted research in bioreactor landfills, which operate under the "wet cell" theory where moisture is added to enhance degradation. The Research section contains a plethora of material, including the Bioreactor Presentation, which consists of 60 slides outlining the project and solid waste issues, and A Proposed Bioreactor Landfill Demonstration Project, which is the proposal that started the project. The proposal is a great source of background information about bioreactor landfills. Though not all of the topics listed on the site have active links, the information available is worthwhile.

297

40 CFR Table Tt-1 to Subpart Tt of... - Default DOC and Decay Rate Values for Industrial Waste Landfills  

Code of Federal Regulations, 2013 CFR

...GREENHOUSE GAS REPORTING Industrial Waste Landfills Pt. 98...and Decay Rate Values for Industrial Waste Landfills Industry... 0 0 0 0 Other Industrial Solid Waste (not otherwise...recirculated from company records or engineering estimates and...

2013-07-01

298

Nitrogen management in bioreactor landfills  

SciTech Connect

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

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

2003-07-01

299

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)

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 ?M, 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 ?M, 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 ?M), Zn and Mn. For the oxyanion species such as MoO 4 and WO 4 (average concentration 0.61 ?M), 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 fluctuations in concentration.

Johnson, C. Annette; Kaeppeli, Michael; Brandenberger, Sandro; Ulrich, Andrea; Baumann, Werner

1999-12-01

300

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

PubMed

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 atmospheric air. For one material with elevated levels of fine particles and high organic matter content, methane production impeded the quantification of methane oxidation potentials. Regarding the design of landfill cover layers it was concluded that the magnitude of the expected methane load, the texture and expected compaction of the cover material are key variables that need to be known. Based on these, a column study can serve as an appropriate testing system to determine the methane oxidation capacity of a soil intended as landfill cover material. PMID:21067907

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

2011-05-01

301

Attenuation of landfill leachate pollutants in aquifers  

Microsoft Academic Search

Landfill leachate contains a variety of pollutants that may potentially contaminate the ground water and affect the quality of surface waters and well waters. The literature has been critically reviewed in order to assess the attenuation processes governing the contaminants in leachate?affected aquifers. After an introductory section on leachate composition, the physical and chemical frameworks for the attenuation processes are

Thomas H. Christensen; Peter Kjeldsen; Gorm Heron; Per H. Nielsen; Poul L. Bjerg; Peter E. Holm

1994-01-01

302

The new Waste Law: Challenging opportunity for future landfill operation in Indonesia.  

PubMed

The Waste Law No. 18/2008 Article 22 and 44 require the local governments to run environmentally sound landfill. Due to the widespread poor quality of waste management in Indonesia, this study aimed to identify the current situation by evaluating three selected landfills based on the ideal conditions of landfill practices, which are used to appraise the capability of local governments to adapt to the law. The results indicated that the local governments have problems of insufficient budget, inadequate equipment, uncollected waste and unplanned future landfill locations. All of the selected landfills were partially controlled landfills with open dumping practices predominating. In such inferior conditions the implementation of sanitary landfill is not necessarily appropriate. The controlled landfill is a more appropriate solution as it offers lower investment and operational costs, makes the selection of a new landfill site unnecessary and can operate with a minimum standard of infrastructure and equipment. The sustainability of future landfill capacity can be maintained by utilizing the old landfill as a profit-oriented landfill by implementing a landfill gas management or a clean development mechanism project. A collection fee system using the pay-as-you-throw principle could increase the waste income thereby financing municipal solid waste management. PMID:20935025

Meidiana, Christia; Gamse, Thomas

2011-01-01

303

The Sanitarv Landfill in the Subkctic  

Microsoft Academic Search

A field study of two and a half years was conducted into the application of the sanitary landfill to the Subarctic. Temperatures and gas concentrations were observed in an experimental cell and groundwater quality measured on the periphery. Carbon dioxide concentrations peaked during the warmer periods corresponding to minimum oxygen concentrations. No methane was ever detected nor were significant changes

ROBERT O. STRAUGHNI

304

Biotic systems to mitigate landfill methane emissions.  

PubMed

Landfill gases produced during biological degradation of buried organic wastes include methane, which when released to the atmosphere, can contribute to global climate change. Increasing use of gas collection systems has reduced the risk of escaping methane emissions entering the atmosphere, but gas capture is not 100% efficient, and further, there are still many instances when gas collection systems are not used. Biotic methane mitigation systems exploit the propensity of some naturally occurring bacteria to oxidize methane. By providing optimum conditions for microbial habitation and efficiently routing landfill gases to where they are cultivated, a number of bio-based systems, such as interim or long-term biocovers, passively or actively vented biofilters, biowindows and daily-used biotarps, have been developed that can alone, or with gas collection, mitigate landfill methane emissions. This paper reviews the science that guides bio-based designs; summarizes experiences with the diverse natural or engineered substrates used in such systems; describes some of the studies and field trials being used to evaluate them; and discusses how they can be used for better landfill operation, capping, and aftercare. PMID:18338700

Huber-Humer, Marion; Gebert, Julia; Hilger, Helene

2008-02-01

305

Reducing Open Cell Landfill Methane Emissions with a Bioactive Alternative Daily  

SciTech Connect

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 prone to rapid desiccation. Bacterial adsorption onto foam padding, natural sponge, and geotextile was successful. The most important factor for success appeared to be water holding capacity. Prototype biotarps made with geotextiles plus adsorbed methane oxidizing bacteria were tested for their responses to temperature, intermittent starvation, and washing (to simulate rainfall). The prototypes were mesophilic, and methane oxidation activity remained strong after one cycle of starvation but then declined with repeated cycles. Many of the cells detached with vigorous washing, but at least 30% appeared resistant to sloughing. While laboratory landfill simulations showed that four-layer composite biotarps made with two different types of geotextile could remove up to 50% of influent methane introduced at a flux rate of 22 g m{sup -2} d{sup -1}, field experiments did not yield high activity levels. Tests revealed that there were high hour-to-hour flux variations in the field, which, together with frequent rainfall events, confounded the field testing. Overall, the findings suggest that a methanotroph embedded biotarp appears to be a feasible strategy to mitigate methane emission from landfill cells, although the performance of field-tested biotarps was not robust here. Tarps will likely be best suited for spring and summer use, although the methane oxidizer population may be able to shift and adapt to lower temperatures. The starvation cycling of the tarp may require the capacity for intermittent reinoculation of the cells, although it is also possible that a subpopulation will adapt to the cycling and become dominant. Rainfall is not expected to be a major factor, because a baseline biofilm will be present to repopulate the tarp. If strong performance can be achieved and documented, the biotarp concept could be extended to include interception of other compounds beyond methane, such as volatile aromatic hydrocarbons and chlorinated solvents.

Helene Hilger; James Oliver; Jean Bogner; David Jones

2009-03-31

306

Comet Halley - The gas composition derived from space missions  

NASA Astrophysics Data System (ADS)

Important results have been obtained by the Vega and Giotto missions concerning Comet Halley's gas composition. Water vapor and CO2 have been identified with respective production rates of about 10 to the 30th/s and 10 to the 28th/s. In addition, there is evidence for the presence of hydrocarbons and/or carbonaceous material in large amounts in the immediate vicinity of the nucleus.

Encrenaz, T.

1987-09-01

307

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

SciTech Connect

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.

Gregory Corman; Krishan Luthra

2005-09-30

308

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

USGS Publications Warehouse

Gas hydrate samples were recovered from four sites (Sites 994, 995, 996, and 997) along the crest of the Blake Ridge during Ocean Drilling Program (ODP) Leg 164. At Site 996, an area of active gas venting, pockmarks, and chemosynthetic communities, vein-like gas hydrate was recovered from less than 1 meter below seafloor (mbsf) and intermittently through the maximum cored depth of 63 mbsf. In contrast, massive gas hydrate, probably fault filling and/or stratigraphically controlled, was recovered from depths of 260 mbsf at Site 994, and from 331 mbsf at Site 997. Downhole-logging data, along with geochemical and core temperature profiles, indicate that gas hydrate at Sites 994, 995, and 997 occurs from about 180 to 450 mbsf and is dispersed in sediment as 5- to 30-m-thick zones of up to about 15% bulk volume gas hydrate. Selected gas hydrate samples were placed in a sealed chamber and allowed to dissociate. Evolved gas to water volumetric ratios measured on seven samples from Site 996 ranged from 20 to 143 mL gas/mL water to 154 mL gas/mL water in one sample from Site 994, and to 139 mL gas/mL water in one sample from Site 997, which can be compared to the theoretical maximum gas to water ratio of 216. These ratios are minimum gas/water ratios for gas hydrate because of partial dissociation during core recovery and potential contamination with pore waters. Nonetheless, the maximum measured volumetric ratio indicates that at least 71% of the cages in this gas hydrate were filled with gas molecules. When corrections for pore-water contamination are made, these volumetric ratios range from 29 to 204, suggesting that cages in some natural gas hydrate are nearly filled. Methane comprises the bulk of the evolved gas from all sites (98.4%-99.9% methane and 0%-1.5% CO2). Site 996 hydrate contained little CO2 (0%-0.56%). Ethane concentrations differed significantly from Site 996, where they ranged from 720 to 1010 parts per million by volume (ppmv), to Sites 994 and 997, 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.

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

2000-01-01

309

Acid gas scrubbing by composite solvent-swollen membranes  

DOEpatents

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.

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

1988-04-12

310

Acid gas scrubbing by composite solvent-swollen membranes  

DOEpatents

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.

Matson, Stephen L. (Harvard, MA) [Harvard, MA; Lee, Eric K. L. (Acton, MA) [Acton, MA; Friesen, Dwayne T. (Bend, OR) [Bend, OR; Kelly, Donald J. (Bend, OR) [Bend, OR

1988-01-01

311

Environmental problems associated with the development and operation of a lined and unlined landfill site: a case study demonstrating two landfill sites in Patra, Greece  

NASA Astrophysics Data System (ADS)

The present work demonstrates the environmental problems associated with the development and operation of a lined and unlined landfill site, both used for municipal solid waste landfilling, that are situated next to the city of Patra, Greece. Findings from a detailed site investigation as well calculations on hydrologic evaluation of landfill’s performance and measurements on leachate composition proved that the lined landfill site is more secure and environmental friendly compared with the unlined landfill site. Even though, until today, there is no evidence from near boreholes for severe contamination problems generated by any of the two landfills, in the forthcoming future several environmental problems are expected to occur from the unlined site. In addition the prevailing hydrogeotechnical conditions indicated that the unlined site is a potential source of contamination; hence extra remedial measures should be received by the local authorities to prevent severe contamination in soil and groundwater.

Depountis, Nikos; Koukis, George; Sabatakakis, Nikos

2009-02-01

312

CORRIGENDUM: Normalization of natural gas composition data measured by gas chromatography Normalization of natural gas composition data measured by gas chromatography  

NASA Astrophysics Data System (ADS)

The authors unintentionally omitted to mention work [1] that pre-dated the cited work by Haesselbarth and Bremser [2]. This work formulated the problem within a mathematical framework and had been cited by the authors in a previous publication [3]. The major conclusion of the authors' work goes beyond the mathematics presented in [1] and [2] because it is applied to several real data sets and the results are interpreted in practical terms. References [1] Haesselbarth W and Bremser W 2001 Correlation in natural gas composition data Proc. Int. Gas Research Conf. (Amsterdam) [2] Haesselbarth W and Bremser W 2007 Metrologia 44 128-45 [3] Brown A S, Milton M J T, Cowper C J, Squire G D, Bremser W and Branch R W 2004 J. Chromatogr. A 1040 215-25

Milton, Martin J. T.; Harris, Peter M.; Brown, Andrew S.; Cowper, Chris J.

2009-11-01

313

Gas Composition Issues and Implications for Natural Gas Vehicles and Fueling Stations. Topical Report, October 1993-June 1996.  

National Technical Information Service (NTIS)

This report provides a general overview of gas composition issues related to compressed natural gas for vehicles, recent research, and practical experience gained in the field. Its purpose is to summarize and communicate information and, where possible, t...

S. Schaedel M. Czachorski P. Rowley M. Richards Y. Shikari

1996-01-01

314

The influence of atmospheric pressure on landfill methane emissions.  

PubMed

Landfills are the largest source of anthropogenic methane (CH4) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH4 emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH4 emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m3 CH4 min(-1). A simple regression model of our results was used to calculate an annual emission rate of 8.4 x 10(6) m3 CH4 year(-1). These data, along with CH4 oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH4 generation at this landfill. A reported gas collection rate of 7.1 x 10(6) m3 CH4 year(-1) and an estimated annual rate of CH4 oxidation by cover soils of 1.2 x 10(6) m3 CH4 year(-1) resulted in a calculated annual CH4 generation rate of 16.7 x 10(6) m3 CH4 year(-1). These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential. PMID:12957154

Czepiel, P M; Shorter, J H; Mosher, B; Allwine, E; McManus, J B; Harriss, R C; Kolb, C E; Lamb, B K

2003-01-01

315

Modelling biogas production of solid waste: application of the BGP model to a synthetic landfill  

NASA Astrophysics Data System (ADS)

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.

Rodrigo-Ilarri, Javier; Segura-Sobrino, Francisco

2013-04-01

316

Effects of Gas Composition and Geothermal Properties on the Thickness and Depth of Natural-Gas-Hydrate Zones  

Microsoft Academic Search

When natural gas and water contact at low temperature and high pressure, gas hydrates can form. In colder climates (such as Alaska, Northern Canada, and Siberia) and beneath the oceans, conditions are appropriate for gas-hydrate formation. This paper gives the depths and potential thicknesses of such hydrate formations as a function of the geothermal gradient, gas composition, and where appropriate,

G. D. Holder; R. D. Malone; W. F. Lawson

1987-01-01

317

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

PubMed

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. PMID:24755356

Scheutz, Charlotte; Pedersen, Rasmus Broe; Petersen, Per Haugsted; Jørgensen, Jørgen Henrik Bjerre; Ucendo, Inmaculada Maria Buendia; Mønster, Jacob G; Samuelsson, Jerker; Kjeldsen, Peter

2014-07-01

318

Noble Gas Compositions in Muong Nong-type Tektites  

NASA Astrophysics Data System (ADS)

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 concentrations in tektites, impact glasses, and Muong Nong-type tektites are shown in Fig. 1. Tektites shown are splash-form types collected from three strewn fields [2,6]. Impact glasses shown are Aouelloul, Zhamanshin, Libyan Desert glasses [4], and Darwin glass [3]. Heavy noble gas concentrations in Muong Nong-type tektites are higher than those in splash- form tektites and are similar to those in impact glasses. From the results of laser probe and crushing analysis of noble gases in Muong Nong-type tektites, it seems that vesicles are unevenly distributed in these samples and that large amounts of noble gases exist in theses vesicles. Neon isotopic compositions in vesicles in Muong Nong-type tektites agree well with a terrestrial atmosphere. 40Ar/36Ar ratios in vesicles are higher than that in air, suggesting that radiogenic 40Ar exists in vesicles and/or that radiogenic 40Ar in glass may degas by crushing. Fig. 1, which appears here in the hard copy, shows noble gas concentrations in splash-form tektites (open circles), impact glasses (open triangles), and Muong Nong-type tektites (filled cirles). References: [1] Koeberl C. (1988) Proc. NIPR Symp. Antarct. Meteorites, 1, 261-290. [2] Matsubara K. and Matsuda J. (1991) Meteoritics, 26, 217-220. [3] Matsuda J. et al. (1989) GCA, 53, 3025-3033. [4] Matsubara K. et al. (1991) GCA, 55, 2951-2955. [5] Koeberl C. (1992) GCA, 56, 1033-1064. [6] Hennecke E. W. et al. (1975) JGR, 80, 2931-2934.

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

1993-07-01

319

Gas separation by composite solvent-swollen membranes  

DOEpatents

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.

Matson, Stephen L. (Harvard, MA) [Harvard, MA; Lee, Eric K. L. (Acton, MA) [Acton, MA; Friesen, Dwayne T. (Bend, OR) [Bend, OR; Kelly, Donald J. (Bend, OR) [Bend, OR

1989-01-01

320

Gas separation by composite solvent-swollen membranes  

DOEpatents

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.

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

1989-04-25

321

Static headspace versus head space solid-phase microextraction (HS-SPME) for the determination of volatile organochlorine compounds in landfill leachates by gas chromatography  

Microsoft Academic Search

The determination of five volatile organochlorine compounds, VOX (chloroform, 1,1,1-trichloroethane, carbon tetrachloride, trichloroethene and tetrachloroethene) in raw landfill leachates and biologically cleansed leachates by GC-MS is investigated. Two extraction and preconcentration procedures were evaluated for recovery of such analies from the samples, including static headspace (HS) and solid phase microextraction by sampling the headspace above the sample (HS-SPME). Optimisation of

J. C Flórez Menéndez; M. L Fernández Sánchez; E Fernández Mart??nez; J. E Sánchez Ur??a; A Sanz-Medel

2004-01-01

322

Atomistic level description of phase diagram of gas clathrate hydrates with complex gas compositions  

NASA Astrophysics Data System (ADS)

An approach has been realized that allows us to construct a p-T phase diagrams of various gas hydrates, three-dimensional hydrogen-bonded water structures in which water molecules arrange themselves in a cage-like (host) structure around gas (guest) molecules, with complex gas compositions [1-2]. In order to evaluate the parameters of weak interactions, a TDDFT formalism and LDA technique entirely in real space have been implemented for calculations of vdW dispersion coefficients for atoms within the all-electron mixed-basis approach. The combination of both methods enables one to calculate thermodynamic properties of clathrate hydrates without resorting to any empirical parameter fittings. Using the proposed method it is possible not only confirm the existing experimental data but also predict the unknown region of thermodynamic stability of clathrate hydrates, and also propose the gas storage ability as well as the gas composition for which high-stability region of clathrate hydrates can be achieved. The proposed method is quite general and can be applied to the various non-stoichiometric inclusion compounds with weak guest-host interactions.[4pt] [1] R. V. Belosludov et al. J. Chem Phys. 131 (2009) 244510[0pt] [2] R. V. Belosludov et al. Mol. Simul. 38 (2012) 773.

Belosludov, R.; Mizuseki, H.; Kawazoe, Y.; Subbotin, O.; Belosludov, V.

2013-03-01

323

Methanotrophic communities in a landfill cover soil as revealed by [ 13C] PLFAs and respiratory quinones: Impact of high methane addition and landfill leachate irrigation  

Microsoft Academic Search

The soil microbial communities of a landfill cover substrate, which was treated with landfill gas (100lCH4m?2d?1) and landfill leachate for 1.5 years, were investigated by phospholipid fatty acid (PLFA), ergosterol and respiratory quinone analyses. The natural 13C depletion of methane was used to assess the activity of methanotrophs and carbon turnover in the soil system. Under methane addition, the soil

Andrea Watzinger; Michael Stemmer; Michael Pfeffer; Frank Rasche; Thomas G. Reichenauer

2008-01-01

324

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

DOEpatents

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.

Doehler, Joachim (Union Lake, MI) [Union Lake, MI

1994-12-20

325

Minimizing N 2O fluxes from full-scale municipal solid waste landfill with properly selected cover soil  

Microsoft Academic Search

Municipal solid waste landfills emit nitrous oxide (N2O) gas. Assuming that the soil cover is the primary N2O source from landfills, this study tested, during a four-year project, the hypothesis that the proper use of chosen soils with fine texture minimizes N2O emissions. A full-scale sanitary landfill, a full-scale bioreactor landfill and a cell planted with Nerium indicum or Festuca

Houhu ZHANG; Pinjing HE; Liming SHAO; Xian QU; Duujong LEE

2008-01-01

326

Methods of Sensing Land Pollution from Sanitary Landfills  

NASA Technical Reports Server (NTRS)

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.

Nosanov, Myron Ellis; Bowerman, Frank R.

1971-01-01

327

Municipal landfill leachate management  

SciTech Connect

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.

Kusterer, T.; Willson, R. [Montgomery County Div. of Solid Waste Services, Rockville, MD (United States); Bruce, S.C.; Tissue, E. Lou, P.J. [Roy F. Weston Inc., Philadelphia, PA (United States)

1998-12-31

328

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)...

329

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

Microsoft Academic Search

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

A. V. Poletayev

2009-01-01

330

The importance of shale composition and pore structure upon gas storage potential of shale gas reservoirs  

Microsoft Academic Search

The effect of shale composition and fabric upon pore structure and CH4 sorption is investigated for potential shale gas reservoirs in the Western Canadian Sedimentary Basin (WCSB). Devonian–Mississippian (D–M) and Jurassic shales have complex, heterogeneous pore volume distributions as identified by low pressure CO2 and N2 sorption, and high pressure Hg porosimetry. Thermally mature D–M shales (1.6–2.5%VRo) have Dubinin–Radushkevich (D–R)

Daniel J. K. Ross; R. Marc Bustin

2009-01-01

331

Biotic landfill cover treatments for mitigating methane emissions.  

PubMed

Landfill methane (CH4) emissions have been cited as one of the anthropogenic gas releases that can and should be controlled to reduce global climate change. This article reviews recent research that identifies ways to enhance microbial consumption of the gas in the aerobic portion of a landfill cover. Use of these methods can augment CH4 emission reductions achieved by gas collection or provide a sole means to consume CH4 at small landfills that do not have active gas collection systems. Field studies indicate that high levels of CH4 removal can be achieved by optimizing natural soil microbial processes. Further, during biotic conversion, not all of the CH4 carbon is converted to carbon dioxide (CO2) gas and released to the atmosphere; some of it will be sequestered in microbial biomass. Because biotic covers can employ residuals from other municipal processes, financial benefits can also accrue from avoided costs for residuals disposal. PMID:12733810

Hilgeri, Helene; Humer, Marion

2003-05-01

332

Landfills in New York City: 1844--1994  

Microsoft Academic Search

Historic topographic maps are reviewed to locate landfills constructed within New York City during four time intervals between 1844 and 1994. A total of 184.75 km² (45,650 acres) of landfill are identified (approximately 20% of the study area). Data are not available to determine the fill composition at most sites but literature sources indicate that municipal solid waste (MSW) has

Daniel C. Walsh; Robert G. LaFleur

1995-01-01

333

Gas and condensate composition in the deep Tuscaloosa trend, southern Louisiana - influence of oil and wet gas cracking  

Microsoft Academic Search

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

G. E. Claypool; M. A. Rooney; A. K. Vuletich

1996-01-01

334

Simulations of Flow, Transport, and Biodegradation in Landfills  

Microsoft Academic Search

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

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

2002-01-01

335

Tunable composite membranes for gas separations. Quarterly technical progress report, May--July 1996  

SciTech Connect

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.

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

1996-08-05

336

Generating CO{sub 2}-credits through landfill in situ aeration  

SciTech Connect

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.

Ritzkowski, M., E-mail: m.ritzkowski@tu-harburg.d [Institute of Environmental Technology and Energy Economics, Hamburg University of Technology, Harburger Schlossstr. 36, D-21079 Hamburg (Germany); Stegmann, R. [Consultants for Waste Management, Prof. R. Stegmann and Partner, Schellerdamm 19-21, D-21079 Hamburg (Germany)

2010-04-15

337

Optimization of diagnostic microarray for application in analysing landfill methanotroph communities under different plant covers.  

PubMed

Landfill sites are responsible for 6-12% of global methane emission. Methanotrophs play a very important role in decreasing landfill site methane emissions. We investigated the methane oxidation capacity and methanotroph diversity in lysimeters simulating landfill sites with different plant vegetations. Methane oxidation rates were 35 g methane m-2 day-1 or higher for planted lysimeters and 18 g methane m-2 day-1 or less for bare soil controls. Best methane oxidation, as displayed by gas depth profiles, was found under a vegetation of grass and alfalfa. Methanotroph communities were analysed at high throughput and resolution using a microbial diagnostic microarray targeting the particulate methane monooxygenase (pmoA) gene of methanotrophs and functionally related bacteria. Members of the genera Methylocystis and Methylocaldum were found to be the dominant members in landfill site simulating lysimeters. Soil bacterial communities in biogas free control lysimeters, which were less abundant in methanotrophs, were dominated by Methylocaldum. Type Ia methanotrophs were found only in the top layers of bare soil lysimeters with relatively high oxygen and low methane concentrations. A competetive advantage of type II methanotrophs over type Ia methanotrophs was indicated under all plant covers investigated. Analysis of average and individual results from parallel samples was used to identify general trends and variations in methanotroph community structures in relation to depth, methane supply and plant cover. The applicability of the technology for the detection of environmental perturbations was proven by an erroneous result, where an unexpected community composition detected with the microarray indicated a potential gas leakage in the lysimeter being investigated. PMID:15008813

Stralis-Pavese, Nancy; Sessitsch, Angela; Weilharter, Alexandra; Reichenauer, Thomas; Riesing, Johann; Csontos, József; Murrell, J Colin; Bodrossy, Levente

2004-04-01

338

Structure and composition analysis of natural gas hydrates: 13C NMR spectroscopic and gas uptake measurements of mixed gas hydrates.  

PubMed

Gas hydrates are becoming an attractive way of storing and transporting large quantities of natural gas, although there has been little effort to understand the preferential occupation of heavy hydrocarbon molecules in hydrate cages. In this work, we present the formation kinetics of mixed hydrate based on a gas uptake measurement during hydrate formation, and how the compositions of the hydrate phase are varied under corresponding formation conditions. We also examine the effect of silica gel pores on the physical properties of mixed hydrate, including thermodynamic equilibrium, formation kinetics, and hydrate compositions. It is expected that the enclathration of ethane and propane is faster than that of methane early stage hydrate formation, and later methane becomes the dominant component to be enclathrated due to depletion of heavy hydrocarbons in the vapor phase. The composition of the hydrate phase seems to be affected by the consumed amount of natural gas, which results in a variation of heating value of retrieved gas from mixed hydrates as a function of formation temperature. 13C NMR experiments were used to measure the distribution of hydrocarbon molecules over the cages of hydrate structure when it forms either from bulk water or water in silica gel pores. We confirm that 70% of large cages of mixed hydrate are occupied by methane molecules when it forms from bulk water; however, only 19% of large cages of mixed hydrate are occupied by methane molecules when it forms from water in silica gel pores. This result indicates that the fractionation of the hydrate phase with heavy hydrocarbon molecules is enhanced in silica gel pores. In addition when heavy hydrocarbon molecules are depleted in the vapor phase during the formation of mixed hydrate, structure I methane hydrate forms instead of structure II mixed hydrate and both structures coexist together, which is also confirmed by 13C NMR spectroscopic analysis. PMID:19658414

Seo, Yutaek; Kang, Seong-Pil; Jang, Wonho

2009-09-01

339

Improvement of gas sensing performance of carbon black\\/waterborne polyurethane composites: Effect of crosslinking treatment  

Microsoft Academic Search

When carbon black (CB) filled waterborne polyurethane (WPU) composites are exposed to organic solvent vapors, electrical resistance of the materials increases rapidly. They can thus serve as gas sensors. To improve the composites’ performance for practical applications, crosslinking agent was added to the composite latexes, forming intra-molecular crosslinked networks among the matrix polymer of the composites. The method greatly increased

Shi Guo Chen; Ji Wen Hu; Ming Qiu Zhang; Min Zhi Rong; Qiang Zheng

2006-01-01

340

Influence of Technological Cycles of Natural Gas Treatment on Radioactive Radon Content in its Composition  

Microsoft Academic Search

Radioactive gas radon is found in the composition of natural gas. Radon is formed as a result of radioactive decay of natural radionuclides and it goes into the natural gas. Despite the fact that certain part of radon volatilizes or decays in the process of natural gas production, transportation and processing even then a great quantity of radioactive substances come

A. A. GARIBOV; G. F. MIRALAMOV; R. C. H. MAMEDOV; G. Z. VELIBEKOVA

341

Environmental Impacts, Institutional Problems, and Research Needs of Sanitary Landfill Methane Recovery.  

National Technical Information Service (NTIS)

Solid waste disposal sites may become public and corporate assets when landfill gas (LFG) energy extraction systems are applied. When methane gas, the primary component of LFG, is extracted, a useful energy source is developed and explosion and fire hazar...

G. M. Kaszynski J. R. LaFevers R. L. Beck K. L. Harrington F. Kremer

1981-01-01

342

Influence of Gas Composition on Hydrogen Sulfide Removal at Moderate Temperature  

Microsoft Academic Search

The influence of gas composition on hydrogen sulfide removal from coal gas by zinc oxide sorbent was investigated at moderate temperature using TG technique. It was found that the removal of H2S by ZnO can vary greatly depending on the gas composition. Addition of H2, H2O to the inlet gas stream could promote the reaction rate, whereas the desulfurization was

Hui-Ling Fan; Ju Shangguan; Li-Tong Liang; Fang Shen

2011-01-01

343

Use of stable isotopes to determine methane oxidation in landfill cover soils  

Microsoft Academic Search

The mean isotopic composition of CH4 emitted from six New England (United States) landfills was 13C and D enriched (-48.1 to -50.40\\/00 and -273 to -2810\\/00) relative to anoxic zone landfill CH4 (mean values of -55.9 to -56.20\\/00 and -296 to -3000\\/00) owing to the oxidation of methane as it was transported from the landfill to the atmosphere through the

K. Liptay; J. Chanton; P. Czepiel; B. Mosher

1998-01-01

344

Landfill modelling in LCA - a contribution based on empirical data.  

PubMed

Landfills at various stages of development, depending on their age and location, can be found throughout Europe. The type of facilities goes from uncontrolled dumpsites to highly engineered facilities with leachate and gas management. In addition, some landfills are designed to receive untreated waste, while others can receive incineration residues (MSWI) or residues after mechanical biological treatment (MBT). Dimension, type and duration of the emissions from landfills depend on the quality of the disposed waste, the technical design, and the location of the landfill. Environmental impacts are produced by the leachate (heavy metals, organic loading), emissions into the air (CH(4), hydrocarbons, halogenated hydrocarbons) and from the energy or fuel requirements for the operation of the landfill (SO(2) and NO(x) from the production of electricity from fossil fuels). To include landfilling in an life-cycle assessment (LCA) approach entails several methodological questions (multi-input process, site-specific influence, time dependency). Additionally, no experiences are available with regard to mid-term behaviour (decades) for the relatively new types of landfill (MBT landfill, landfill for residues from MSWI). The present paper focuses on two main issues concerning modelling of landfills in LCA: Firstly, it is an acknowledged fact that emissions from landfills may prevail for a very long time, often thousands of years or longer. The choice of time frame in the LCA of landfilling may therefore clearly affect the results. Secondly, the reliability of results obtained through a life-cycle assessment depends on the availability and quality of Life Cycle Inventory (LCI) data. Therefore the choice of the general approach, using multi-input inventory tool versus empirical results, may also influence the results. In this paper the different approaches concerning time horizon and LCI will be introduced and discussed. In the application of empirical results, the presence of data gaps may limit the inclusion of several impact categories and therefore affect the results obtained by the study. For this reason, every effort has been made to provide high-quality empirical LCI data for landfills in Central Europe. PMID:17433660

Obersteiner, Gudrun; Binner, Erwin; Mostbauer, Peter; Salhofer, Stefan

2007-01-01

345

Attenuation of landfill leachate at two uncontrolled landfills  

NASA Astrophysics Data System (ADS)

Attenuation characteristics of landfill leachate were examined for two uncontrolled landfills in Korea. The two landfills containing municipal wastes without appropriate bottom liner and leachate treatment system have different landfill age, waste volume, and most importantly different hydrogeologic settings. One landfill (Cheonan landfill) is situated in an open flat area while the other (Wonju landfill) is located in a valley. Variations of various parameters including dissolved organic carbon (DOC), dissolved oxygen (DO), alkalinity, pH, electrical conductivity (EC), redox potential (ORP), ammonia (NH3), nitrate (NO{3/-}), sulfate (SO{4/2-}), and chloride (Cl-) were examined along groundwater flow path. All these parameters were analyzed every month for a year. In the interior of the landfills, typical anaerobic conditions revealed by low DO and NO3 concentrations, negative ORP values, high NH3, alkalinity, and Cl- concentrations were observed. Generally, higher levels of contaminants (DOC, NH3, and Cl-) were detected in the dry season while they were greatly lowered in the wet season. Significantly, large decrease of Cl- concentration in the wet season indicates that the dilution or mixing is one of dominant attenuation mechanisms of leachate. But detailed variation behaviors in the two landfills are different and they were largely dependent on permeability of surface and subsurface layers. The intermediately permeable surface of the landfills receives part of direct rainfall infiltration but most rainwater is lost to fast runoff. The practically impermeable surface of clayey silt (paddy field) at immediately adjacent to the Cheonan landfill boundary prevented direct rainwater infiltration and hence redox condition of the ground waters were largely affected by that of the upper landfill and the less permeable materials beneath the paddy fields prohibited dispersion of the landfill leachate into down gradient area. In the Wonju landfill, there are three different permeability divisions, the landfill region, the sandy open field and the paddy field. Roles of the landfill and paddy regions are very similar to those at the Cheonan. The very permeable sandy field receiving a large amount of rainwater infiltration plays a key role in controlling redox condition of the down gradient area and contaminant migration. This paper reports details of the attenuation and redox conditions of the landfill leachates at the two uncontrolled landfills.

Lee, Jin-Yong; Cheon, Jeong-Yong; Kwon, Hyung-Pyo; Yoon, Hee-Sung; Lee, Seong-Sun; Kim, Jong-Ho; Park, Joung-Ku; Kim, Chang-Gyun

2006-12-01

346

Temperature dependence of gas sensing behaviour of TiO2 doped PANI composite thin films  

NASA Astrophysics Data System (ADS)

In the present work we have reported the effect of temperature on the gas sensing properties of TiO2 doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and TiO2 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 TiO2 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.

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

2014-04-01

347

Utilizing coal fly ash as a landfill barrier material  

Microsoft Academic Search

The chemical barrier properties of a composite of coal fly ash, lime dust and bentonite were studied as a potential barrier material for a landfill. An experimental study was performed to measure the hydraulic and chemical barrier properties of the material using both water and a synthetic municipal solid waste (MSW) leachate. The composite material was found to have a

C. T. Nhan; J. W. Graydon; D. W. Kirk

1996-01-01

348

Development of computer simulations for landfill methane recovery  

SciTech Connect

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.

Massmann, J.W.; Moore, C.A.; Sykes, R.M.

1981-12-01

349

Temperature as an indicator of landfill behavior  

Microsoft Academic Search

The utility of landfill temperature measurements both as a means of understanding landfill behavior and the interpretation of anomalous data points is explored by demonstration in a case study application. The availability of a pathway facilitating easy intrusion of atmospheric OZ into a landfill is shown to cause aerobic conditions and spontaneous combustion, during landfill pumping experiments. The landfill temperature

A. J. Crutcher; F. A. Rovers; E. A. McBean

1982-01-01

350

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

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.

Lorenson, T. D.

1999-01-01

351

Prediction of flue gas composition of an incinerator based on a nonequilibrium-reaction approach  

Microsoft Academic Search

A nonequilibrium-reaction model is developed to predict the flue gas composition of an incinerator for solid waste combustion and gasification. The model may also be effectively utilized to predict the composition of exit gas from the primary chamber of an incinerator where invariably substoichiometric combustion conditions exist. The model assumes that the drying and pyrolysis of waste occurs in sequence

G. Rao; S. C. Saxena

1993-01-01

352

Gas composition issues and implications for natural gas vehicles and fueling stations. Topical report, October 1993June 1996  

Microsoft Academic Search

This report provides a general overview of gas composition issues related to compressed natural gas for vehicles, recent research, and practical experience gained in the field. Its purpose is to summarize and communicate information and, where possible, to help fuel providers, original equipment manufacturers, and other members of the industry to formulate appropriate responses to emerging challenges and issues. Three

S. Schaedel; M. Czachorski; P. Rowley; M. Richards; Y. Shikari

1996-01-01

353

Evaluation of simultaneous biodegradation of methane and toluene in landfill covers.  

PubMed

The biodegradation of CH4 and toluene in landfill cover soil (LCS) and waste biocover soil (WBS) was investigated with a serial toluene concentration in the headspace of landfill cover microcosms in this study. Compared with the LCS sample, the higher CH4 oxidation activity and toluene-degrading capacity occurred in the WBS sample. The co-existence of toluene in landfill gas would positively or negatively affect CH4 oxidation, mainly depending on the toluene concentrations and exposure time. The nearly complete inhibition of toluene on CH4 oxidation was observed in the WBS sample at the toluene concentration of ?80,000mgm(-3), which was about 10 times higher than that in the LCS sample. The toluene degradation rates in both landfill covers fitted well with the Michaelis-Menten model. These findings showed that WBS was a good alternative landfill cover material to simultaneously mitigate emissions of CH4 and toluene from landfills to the atmosphere. PMID:24801894

Su, Yao; Zhang, Xuan; Wei, Xiao-Meng; Kong, Jiao-Yan; Xia, Fang-Fang; Li, Wei; He, Ruo

2014-06-15

354

KEY COMPARISON: International Comparison CCQM-K16: Composition of natural gas types IV and V  

Microsoft Academic Search

Natural gas is an important energy vector. The determination of its composition is often used as the basis for the calculation of the calorific value. The calorific value in turn is one of the two key parameters used in natural gas trade. In the first series of key comparisons (CCQM-K1e-g), natural gas was already included with three different compositions. These

Adriaan M. H. van der Veen; Hans-Joachim Heine; Freek N. C. Brinkmann; Paul R. Ziel; Ed W. B. de Leer; Wang Lin Zhen; Kenji Kato; Leonid A. Konopelko; Tatjana A. Popova; Yuri I. Alexandrov; Elena N. Kortchagina; Yuri A. Kustikov; Stanislav Musil; Martin J. T. Milton; Franklin Guenther; George Rhoderick

2005-01-01

355

Composite nuclear fuel fabrication methodology for gas fast reactors  

NASA Astrophysics Data System (ADS)

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 characterized to understand the required fabrication techniques and at the same time meet the necessary GFR fuel characteristics.

Vasudevamurthy, Gokul

356

Brownfields and health risks--air dispersion modeling and health risk assessment at landfill redevelopment sites.  

PubMed

Redevelopment of landfill sites in the New Jersey-New York metropolitan area for recreational (golf courses), commercial, and even residential purposes seems to be gaining acceptance among municipal planners and developers. Landfill gas generation, which includes methane and potentially toxic nonmethane compounds usually continues long after closure of the landfill exercise phase. It is therefore prudent to evaluate potential health risks associated with exposure to gas emissions before redevelopment of the landfill sites as recreational, commercial, and, especially, residential properties. Unacceptably high health risks would call for risk management measures such as limiting the development to commercial/recreational rather than residential uses, stringent gas control mechanisms, interior air filtration, etc. A methodology is presented for applying existing models to estimate residual landfill hazardous compounds emissions and to quantify associated health risks. Besides the toxic gas constituents of landfill emissions, other risk-related issues concerning buried waste, landfill leachate, and explosive gases were qualitatively evaluated. Five contiguously located landfill sites in New Jersey intended for residential and recreational redevelopment were used to exemplify the approach. PMID:16869439

Ofungwu, Joseph; Eget, Steven

2006-07-01

357

Study of thin biocovers (TBC) for oxidizing uncaptured methane emissions in bioreactor landfills  

Microsoft Academic Search

Bioreactor landfills are designed to accelerate municipal solid waste biodegradation and stabilization; however, the uncaptured methane gas escapes to the atmosphere during their filling. This research investigates the implementation of a novel methane emission control technique that involves thin biocovers (TBC) placed as intermediate waste covers to oxidize methane without affecting the operation of bioreactor landfills. Batch incubation experiments were

Konstantina Perdikea; Anil K. Mehrotra; J. Patrick A. Hettiaratchi

2008-01-01

358

Isotope fractionation effects by diffusion and methane oxidation in landfill cover soils  

Microsoft Academic Search

When the open system isotope method has been used to determine the methane oxidation efficiency of a landfill cover soil, it has been assumed that gas transport from the landfill is primarily driven by advection, a mechanism that is not associated with isotopic fractionation. A controlled laboratory experiment revealed that this approach underestimated the methane oxidation efficiency because it underestimated

Alex De Visscher; Ingrid De Pourcq; Jeffrey Chanton

2004-01-01

359

Carbon Dioxide Gas Sensing Application of GRAPHENE/Y2O3 Quantum Dots Composite  

NASA Astrophysics Data System (ADS)

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.

Nemade, K. R.; Waghuley, S. A.

360

Microemulsion impregnated catalyst composite and use thereof in a synthesis gas conversion process  

DOEpatents

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.

Abrevaya, H.; Targos, W.M.

1987-12-22

361

Microemulsion impregnated catalyst composite and use thereof in a synthesis gas conversion process  

DOEpatents

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.

Abrevaya, Hayim (Chicago, IL) [Chicago, IL; Targos, William M. (Palatine, IL) [Palatine, IL

1987-01-01

362

Gold-carbon composite thin films for electrochemical gas sensor prepared by reactive plasma sputtering  

NASA Astrophysics Data System (ADS)

We have investigated the properties of gold-carbon composite thin films prepared by a plasma sputtering deposition using argon and methane mixture gas. These composite films have an uneven surface in submicron scale or consist of nano-scale particles of gold polycrystalline. Such morphological properties can be controlled by the sputtering voltage and the partial pressure of methane gas. The working electrode of electrochemical gas sensor has needed a stable gas sensitivity and a good gas selectivity. Our composite film is one of the excellent candidates for a thin film working electrode of electrochemical gas sensor. It is described that the output current of sensor is related to the preparation conditions of the thin films and increase linearly as the concentration of PH 3 gas ranging from 0.1 to 1.0 ppm is increasing.

Okamoto, A.; Suzuki, Y.; Yoshitake, M.; Ogawa, S.; Nakano, N.

1997-01-01

363

Evaluation of Fugitive Emissions at a Former Landfill Site in Colorado Springs, Colorado Using Ground-Based Optical Remote Sensing Technology.  

National Technical Information Service (NTIS)

A former landfill site located in Colorado Springs, Colorado was assessed for landfill gas emissions in support of reuse options for the property. The current owners of the landfill and the State of Colorado requested assistance from the EPA Region 8 Offi...

M. Modrak R. Kagann R. Varma R. A. Hashmonay

2005-01-01

364

The influence of atmospheric pressure on landfill methane emissions  

SciTech Connect

Landfills are the largest source of anthropogenic methane (CH{sub 4}) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH{sub 4} emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH{sub 4} emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m{sup 3} CH{sub 4} min{sup -1}. A simple regression model of our results was used to calculate an annual emission rate of 8.4x10{sup 6} m{sup 3} CH{sub 4} year{sup -1}. These data, along with CH{sub 4} oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH{sub 4} generation at this landfill. A reported gas collection rate of 7.1x10{sup 6} m{sup 3} CH{sub 4} year{sup -1} and an estimated annual rate of CH{sub 4} oxidation by cover soils of 1.2x10{sup 6} m{sup 3} CH{sub 4} year{sup -1} resulted in a calculated annual CH{sub 4} generation rate of 16.7x10{sup 6} m{sup 3} CH{sub 4} year{sup -1}. These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential.

Czepiel, P.M.; Shorter, J.H.; Mosher, B.; Allwine, E.; McManus, J.B.; Harriss, R.C.; Kolb, C.E.; Lamb, B.K

2003-07-01

365

EXPERIMENTAL AND SIMULATED RESULTS DETAILING THE SENSITIVITY OF NATURAL GAS HCCI ENGINES TO FUEL COMPOSITION  

Microsoft Academic Search

Natural gas quality, in terms of the volume fraction of higher hydrocarbons, strongly affects the auto-ignition characteristics of the air-fuel mixture, the engine performance and its controllability. The influence of natural gas composition on engine operation has been investigated both experimentally and through chemical kinetic based cycle simulation. A range of two component gas mixtures has been tested with methane

Scott B. Fiveland; Rey Agama; Magnus Christensen; Bengt Johansson; Joel Hiltner; Fabian Mauss; Dennis N. Assanis

366

Gas sensor for CO and NH3 using polyaniline\\/CNTs composite at room temperature  

Microsoft Academic Search

We fabricated a gas sensor for the detection of a carbon monoxide (CO) and ammonia (NH3) gas using single walled carbon nano tubes (SWNTs) and polyaniline(PANI) composite. The SWNTs were dispersed in sodium dodecyl sulfate (SDS) and were applied over the electrodes of an interdigitated electrodes (DDEs) by photolithography. By using this method, the active area for gas sensing can

Inho Kim; Ki-Young Dong; Byeong-Kwon Ju; Hyang Hee Choi

2010-01-01

367

Heating value, relative density and compression factor for dry or wet natural gas from composition  

Microsoft Academic Search

Calculation of the custody transfer properties of natural gas from compositional analysis is relatively straightforward but requires levels of understanding in practice. Several myths exist concerning these properties which are harmless for technicians, but cause difficulty for engineers. In addition, the question of water in the gas and the air used to burn the gas is a complicating factor which

Kenneth R. Hall; James C. Holste

1995-01-01

368

Effect of corona discharge on the gas composition of the sample flow in a Gas Particle Partitioner.  

PubMed

A Gas Particle Partitioner (GPP) that allows highly efficient separation of gas and particles with no effect on the thermodynamic conditions and substantially no change of the gas composition has been developed. The GPP is a coaxial arrangement with inner and outer electrodes and utilizes a corona discharge to electrically charge the particles and a strong electric field to remove them from the sample flow. Several measures were taken to avoid an influence of the corona discharge on the gas composition. The GPP can be applied for various applications. This paper focuses on the use of the GPP as a pre-filter for gas analyzers, where zero pressure drop and a minimization of the influence of the corona discharge on the gas composition are the main objective. Due to its design, the GPP introduces no changes to the thermodynamic conditions. However, corona discharge is known to produce significant amounts of ozone and oxides of nitrogen. The effect of the corona on the gas composition of the sample flow was determined under various conditions. The gas concentrations strongly depended on several aspects, such as material and diameter of the corona wire and polarity of the corona voltage. Due to the measures taken to minimize an effect on the gas composition, the concentrations of these gases could effectively be reduced. Along with the maximum gas-particle separation efficiency of near 100%, the additional O3 concentration was 42 ppbV and the additional NO2 concentration 15 ppbV. If an efficiency of 95% is acceptable, the added concentrations can be as low as 2.5 ppbV (O3) and 0.5 ppbV (NO2), respectively. PMID:16121267

Asbach, Christof; Kuhlbusch, Thomas A J; Fissan, Heinz

2005-09-01

369

[Aerogenesis evolution of the anaerobic-semiaerobic bioreactor landfill].  

PubMed

A novel bioreactor landfill, the anaerobic-semiaerobic bioreactor landfill (AN-SABL), was devised by combining an anaerobic bioreactor landfill (ANBL) with a semi-aerobic aged refuse biofilter (SAARB). Meanwhile, relevant parameters such as gas production volume and rate, and gas constituents were investigated to provide a theoretical foundation for the collection, utilization and treatment of landfill gas. Results indicated that the gas production of the anaerobic units was inhibited in the AN-SABLs. The gas production rates in the ANBL2 unit and the ANBL3 unit were 49 L x kg(-1) and 39 L x kg(-1) respectively, which were only 94.2% and 75.0% of that in the ANBL1. However, the gas production in the anaerobic unit could be accelerated by increasing the recirculation frequency. The maximum methane content could reach up to 62.67%. Moreover, the gas production volume and velocity in the ANBL were much higher in summer than those in winter, and the gas production peak could be observed with a 12-hour cycle. Besides, the nitrification and the denitrification in the anaerobic units would be enhanced remarkably in the AN-SABLs. It resulted that the content of N2O, which fluctuated between 0.0017% and 4.0179%, was influenced obviously by the seasonal variation and the landfill types. Based on the mathematical model of aerogenesis, the cumulative gas volume of the ANBL increased logarithmically in the initial aerobic phase, then increased linearly in the anaerobic acid phase, and increased exponentially in the methane production of acid phase afterwards. PMID:22946204

Han, Zhi-Yong; Liu, Dan; Li, Qi-Bin

2012-06-01

370

Closed landfills to solar energy power plants: Estimating the solar potential of closed landfills in California  

NASA Astrophysics Data System (ADS)

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.

Munsell, Devon R.

371

A finite element simulation of biological conversion processes in landfills  

SciTech Connect

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.

Robeck, M., E-mail: markus.robeck@uni-due.de [Department of Water and Waste Management, Building Sciences, University of Duisburg-Essen, Universitaetsstrasse 15, 45141 Essen (Germany); Ricken, T. [Institute of Mechanics/Computational Mechanics, Building Sciences, University of Duisburg-Essen, Universitaetsstrasse 15, 45141 Essen (Germany); Widmann, R. [Department of Water and Waste Management, Building Sciences, University of Duisburg-Essen, Universitaetsstrasse 15, 45141 Essen (Germany)

2011-04-15

372

Applying guidance for methane emission estimation for landfills  

SciTech Connect

Quantification of methane emission from landfills is important to evaluate measures for reduction of greenhouse gas emissions. Both the United Nations and the European Union have adopted protocols to ensure quantification of methane emission from individual landfills. The purpose of these protocols is to disclose emission data to regulators and the general public. Criteria such as timeliness, completeness, certainty, comparability, consistency and transparency are set for inclusion of emission data in a publicly accessible database. All methods given as guidance to landfill operators to estimate landfill methane emissions are based on models. In this paper the consequences of applying six different models for estimates of three landfills are explored. It is not the intention of this paper to criticise or validate models. The modelling results are compared with whole site methane emission measurements. A huge difference in results is observed. This raises doubts about the accuracy of the models. It also indicates that at least some of the criteria previously mentioned are not met for the tools currently available to estimate methane emissions from individual landfills. This will inevitably lead to compiling and comparing data with an incomparable origin. Harmonisation of models is recommended. This may not necessarily reduce uncertainty, but it will at least result in comparable, consistent and transparent data.

Scharff, Heijo [NV Afvalzorg, Postbus 2, 1566 ZG Assendelft (Netherlands)]. E-mail: h.scharff@afvalzorg.nl; Jacobs, Joeri [NV Afvalzorg, Postbus 2, 1566 ZG Assendelft (Netherlands)]. E-mail: j.jacobs@afvalzorg.nl

2006-07-01

373

A finite element simulation of biological conversion processes in landfills.  

PubMed

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 100years 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. PMID:20833012

Robeck, M; Ricken, T; Widmann, R

2011-04-01

374

Construction and evaluation of simulated pilot scale landfill lysimeter in Bangladesh.  

PubMed

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 was significantly high and proper treatment will be necessary before discharging the lysimeter leachate into the water bodies. PMID:22464865

Rafizul, Islam M; Howlader, Milon Kanti; Alamgir, Muhammed

2012-11-01

375

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...

376

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

SciTech Connect

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.

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

1997-05-19

377

SUSTAINABLE LANDFILL AND BIOLOGICAL STABILITY  

Microsoft Academic Search

The landfill represents the most common way of municipal solid waste (MSW) disposal. On the other hand the anaerobic degradation of the biodegradable fraction of the landfilled MSW, causes several environmental problems such as the production of methane, VOC odors and leachate, the presence of vectors more - insects, rodents, and birds - public health hazard, explosions and plants toxicity.

Barbara Scaglia; Fabrizio Adani

378

Stabilizing Waste Materials for Landfills  

ERIC Educational Resources Information Center

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)

Environmental Science and Technology, 1977

1977-01-01

379

The Gas Sensing Mechanism of the Low-Dimension Carbon Composites with Metal Oxide Quantum Dots  

NASA Astrophysics Data System (ADS)

In this paper, we obtained three kinds of composite materials which were composed of metal oxides (ZnO, SnO2 and TiO2) and CNTs through catalytic pyrolysis method. Then we carried out the surface morphology, field emission and gas sensitivity properties test for them, and summarized the composite ways of metal oxides/CNTs by comparing three composite properties such as the changes in field emission and gas sensing properties, so that we might explore a set of preparation methods and processes of high performance gas sensors. At the same time, the study of field emission can also provide some improved methods to the traditional display technology.

Ma, Hui; Zhou, Weiman; Yuan, Wu; Jie, Zheng; Liu, Hongzhong; Li, Xin.

380

Gas sensitivity of carbon black\\/waterborne polyurethane composites  

Microsoft Academic Search

The synthesis of conductive composites consisting of waterborne polyurethane (WPU) and carbon black (CB) is reported. Besides the low percolation threshold (0.7–0.95 wt%), the composites are quite sensitive to organic solvent vapors regardless of their polarities as characterized by the drastic changes in conductivity. In the case of polar solvents, negative and positive vapor coefficient phenomena of the composites were

Shi Guo Chen; Ji Wen Hu; Ming Qiu Zhang; Ming Wei Li; Min Zhi Rong

2004-01-01

381

Composition and method for removing hydrogen sulfide from gas streams  

Microsoft Academic Search

This patent describes a composition for oxidizing hydrogen sulfide to form elemental sulfur in the composition and for effecting settling of the elemental sulfur from the composition. It comprises an aqueous solution containing chelated water soluble polyvalent metal ions and at least one water soluble nonionic surfactant having an HLB of from 8 to 10. This patent also describes a

1991-01-01

382

Landfill to Learning Facility  

NASA Astrophysics Data System (ADS)

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.

Venner, L.; Lewicki, S.

2008-11-01

383

NOVEL COMPOSITE MEMBRANES AND PROCESS FOR NATURAL GAS UPGRADING  

Microsoft Academic Search

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

Ben Bikson; Sal Giglia; Jibin Hao

2003-01-01

384

Using observed data to improve estimated methane collection from select U.S. landfills.  

PubMed

The anaerobic decomposition of solid waste in a landfill produces methane, a potent greenhouse gas, and if recovered, a valuable energy commodity. Methane generation from U.S. landfills is usually estimated using the U.S. EPA's Landfill Gas Emissions Model (LandGEM). Default values for the two key parameters within LandGEM, the first-order decay rate (k) and the methane production potential (L0) are based on data collected in the 1990s. In this study, observed methane collection data from 11 U.S. landfills and estimates of gas collection efficiencies developed from site-specific gas well installation data were included in a reformulated LandGEM equation. Formal search techniques were employed to optimize k for each landfill to find the minimum sum of squared errors (SSE) between the LandGEM prediction and the observed collection data. Across nearly all landfills, the optimal k was found to be higher than the default AP-42 of 0.04 yr(-1) and the weighted average decay for the 11 landfills was 0.09 - 0.12 yr(-1). The results suggest that the default k value assumed in LandGEM is likely too low, which implies that more methane is produced in the early years following waste burial when gas collection efficiencies tend to be lower. PMID:23469937

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

2013-04-01

385

Effects of natural gas composition on ignition delay under diesel conditions  

SciTech Connect

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.

Naber, J.D.; Siebers, D.L. [Sandia National Labs., Livermore, CA (United States); Di Julio, S.S. [California State Univ., Northridge, CA (United States). Dept. of Mechanical Engineering; Westbrook, C.K. [Lawrence Livermore National Lab., CA (United States)

1993-12-03

386

Effects of gas composition in headspace and bicarbonate concentrations in media on gas and methane production, degradability, and rumen fermentation using in vitro gas production techniques.  

PubMed

Headspace gas composition and bicarbonate concentrations in media can affect methane production and other characteristics of rumen fermentation in in vitro gas production systems, but these 2 important factors have not been evaluated systematically. In this study, these 2 factors were investigated with respect to gas and methane production, in vitro digestibility of feed substrate, and volatile fatty acid (VFA) profile using in vitro gas production techniques. Three headspace gas compositions (N2+ CO2+ H2 in the ratio of 90:5:5, CO2, and N2) with 2 substrate types (alfalfa hay only, and alfalfa hay and a concentrate mixture in a 50:50 ratio) in a 3×2 factorial design (experiment 1) and 3 headspace compositions (N2, N2 + CO2 in a 50:50 ratio, and CO2) with 3 bicarbonate concentrations (80, 100, and 120 mM) in a 3×3 factorial design (experiment 2) were evaluated. In experiment 1, total gas production (TGP) and net gas production (NGP) was the lowest for CO2, followed by N2, and then the gas mixture. Methane concentration in headspace gas after fermentation was greater for CO2 than for N2 and the gas mixture, whereas total methane production (TMP) and net methane production (NMP) were the greatest for CO2, followed by the gas mixture, and then N2. Headspace composition did not affect in vitro digestibility or the VFA profile, except molar percentages of propionate, which were greater for CO2 and N2 than for the gas mixture. Methane concentration in headspace gas, TGP, and NGP were affected by the interaction of headspace gas composition and substrate type. In experiment 2, increasing concentrations of CO2 in the headspace decreased TGP and NGP quadratically, but increased the concentrations of methane, NMP, and in vitro fiber digestibility linearly, and TMP quadratically. Fiber digestibility, TGP, and NGP increased linearly with increasing bicarbonate concentrations in the medium. Concentrations of methane and NMP were unaffected by bicarbonate concentration, but TMP tended to increase due to increasing bicarbonate concentration. Although total VFA concentration and molar percentage of butyrate were unchanged, the molar percentage of acetate, and acetate-to-propionate ratio decreased, whereas the molar percentage of propionate increased quadratically with increasing bicarbonate concentration. This study demonstrated for the first time that headspace composition, especially CO2 content, and bicarbonate concentration in media could significantly influence gas and methane production, and rumen fermentation in gas production techniques. PMID:23684023

Patra, Amlan Kumar; Yu, Zhongtang

2013-07-01

387

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...

388

Identification of dynamic properties of OII landfill  

Microsoft Academic Search

The performance of landfills during strong earthquake shaking is a matter of considerable concern and deserves to be studied more extensively. This paper investigates the dynamic properties of the OII landfill materials using strong motion recordings, available field measurements, and simplified physical models. Although the earthquakes recorded at the OII landfill generated shear strains as large as 0.08%, the landfill

V. Morochnik; J. P. Bardet; B. Hushmand

1998-01-01

389

Simulation of Miscible Gas Displacement with a Finite Element Compositional Simulator.  

National Technical Information Service (NTIS)

The purpose of the project has been to study miscible gas displacement in oil reservoirs, theoretically and experimentally. In the theoretical part, a one dimensional finite element compositional simulator has been developed for solving miscible two phase...

J. S. Fjellerup

1988-01-01

390

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

NASA Astrophysics Data System (ADS)

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.

Mwiganga, M.; Kansiime, F.

391

The effects of a quadrupole mass analyser on measurement of UHV residual gas composition  

Microsoft Academic Search

The effect of both the quadrupole mass analyser (QMA) and the ion-getter-pump (IGP) on the residual gas composition and on the composition during gas dosing were investigated. At the background pressure the measured height of mass 16 was more than 10–14 times the sum of contributions of methane and oxygen ions from other molecules and a significant amount of inert

Tomàš Jirsàk; Vladimír Nikolajenko

1996-01-01

392

Method and apparatus for off-gas composition sensing  

DOEpatents

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.

Ottesen, David Keith (Livermore, CA); Allendorf, Sarah Williams (Fremont, CA); Hubbard, Gary Lee (Richmond, CA); Rosenberg, David Ezechiel (Columbia, MD)

1999-01-01

393

USE OF LANDFILL BIOREACTORS IN ACCELERATING WASTE DEGRADATION  

EPA Science Inventory

MSW bioreactors offer an innovative way of optimizing existing landfill volume by actively degrading the waste mass within a waste containment system. Bioreactor leachate, gas, and solids monitoring is part of a 5 year CRADA between US EP A and Waste Mgt., Inc. at the Outer Loop ...

394

Occurrence of Phthalate Esters in MSW Landfill Area, Wuhan, China  

Microsoft Academic Search

Samples of groundwater, leachates, surface water and soils were collected from 22 sites in the Municipal solid waste landfill area in Wuhan, Central China. Sixteen phthalate esters (PAEs) were detected by gas chromatography (GC). The results showed that there were one or several PAEs in all the samples and the concentrations of total PAEs in groundwater, leachates, surface water, and

Ying Liang; Hui Liu; Dan Zhang; Cheng Wang; Hecheng Liang; Hesheng Cai

2008-01-01

395

Methane oxidation and microbial exopolymer production in landfill cover soil  

Microsoft Academic Search

In laboratory simulations of methane oxidation in landfill cover soil, methane consumption consistently increased to a peak value and then declined to a lower steady-state value. It was hypothesized that a gradual accumulation of exopolymeric substances (EPS) contributed to decreased methane uptake by clogging soil pores or limiting gas diffusion. This study was conducted to detect and quantify EPS in

Helene A Hilger; David F Cranford; Morton A Barlaz

2000-01-01

396

Are forestation, bio-char and landfilled biomass adequate offsets for the climate effects of burning fossil fuels?  

Microsoft Academic Search

Forestation and landfilling purpose-grown biomass are not adequate offsets for the CO2 emission from burning fossil fuels. Their permanence is insufficiently guaranteed and landfilling purpose-grown biomass may even be counterproductive. As to permanence, bio-char may do better than forests or landfilled biomass, but there are major uncertainties about net greenhouse gas emissions linked to the bio-char life cycle, which necessitate

L. Reijnders

2009-01-01

397

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

NASA Technical Reports Server (NTRS)

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.

Novak, R. C.

1978-01-01

398

Relationships between organic vapor adsorption behaviors and gas sensitivity of carbon black filled waterborne polyurethane composites  

Microsoft Academic Search

Vapor adsorption behavior and its influence on the gas sensitivity of conductive carbon black filled waterborne polyurethane composites were studied. It was found that the traditional swelling model that was applicable for the reversible variation in the composites electrical resistance induced by the solvent uptake was challenged. That is, the higher adsorption quantity was not bound to result in higher

Shi Guo Chen; Xian Lei Hu; Jing Hu; Ming Qiu Zhang; Min Zhi Rong; Qiang Zheng

2006-01-01

399

The Variations Of Fumarolic Gas Compositions In Tatun Volcano Group, Northern Taiwan  

Microsoft Academic Search

Hydrothermal activity is commonly found in northern Taiwan. Helium isotopic compositions of fumarolic samples show that more than 60% mantle source was involved in its gas sources. Carbon and nitrogen isotopic results also show significant mantle signature. It infers that a magma reservoir may exist underneath northern Taiwan. For monitoring purpose, therefor, we systematically analyze the compositions of representative fumarolic

H. E. Lee; T. F. Yang; T. F. Lan; S. Song; S. Tsao

2006-01-01

400

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

PubMed

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

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

2014-06-01

401

Landfill Reclamation Feasibility Study for the Montauk Landfill. Town of East Hampton, New York.  

National Technical Information Service (NTIS)

A landfill reclamation feasibility study was performed at Montauk Landfill in East Hampton, Long Island, New York. The purpose of the study was to determine whether landfill reclamation is a technically and economically feasible alternative to conventiona...

1998-01-01

402

Livingston Parish Landfill Methane Recovery Project (Feasibility Study)  

SciTech Connect

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 economically stressed. The primary reason for this is the recent fundamental shift in the US energy landscape. Abundant supplies of natural gas have put downward pressure on any project that displaces natural gas or natural gas substitutes. Moreover, this shift appears long-term as domestic supplies for natural gas may have been increased for several hundred years. While electricity prices are less affected by natural gas prices than other thermal projects, they are still significantly affected since much of the power in the Entergy cost structure is driven by natural gas-fired generation. Consequently, rates reimbursed by the power company based on their avoided cost structure also face downward pressure over the near and intermediate term. In addition, there has been decreasing emphasis on environmental concerns regarding the production of thermal energy, and as a result both the voluntary and mandatory markets that drive green attribute prices have softened significantly over the past couple of years. Please note that energy markets are constantly changing due to fundamental supply and demand forces, as well as from external forces such as regulations and environmental concerns. At any point in the future, the outlook for energy prices may change and could deem either the electricity generation or pipeline injection project more feasible. This report is intended to serve as the primary background document for subsequent decisions made at Parish staff and governing board levels.

White, Steven

2012-11-15

403

Secondary Porosity and Permeability of Coal vs. Gas Composition and Pressure  

Microsoft Academic Search

We have been investigating the sequestration of atmospheric pollutants by injection into coal seams while at the same time enhancing hydrocarbon productivity by displacement of methane with pollutants. We found that changing the composition of the gas sorbed into the coal changes the porosity and permeability of the coal natural-fracture system owing to gas-content changes, which cause matrix swelling or

Matthew Mavor; William Gunter

2006-01-01

404

Effect of electrolyte composition on the dynamics of hydrogen gas bubble evolution at copper microelectrodes  

Microsoft Academic Search

The dynamics of hydrogen gas bubble evolution at copper microelectrodes in H2SO4 and HCl solutions of various compositions have been studied by means of galvanostatic polarization experiments and simultaneous video taping. As long as the solution contains acid only, gas evolution is dominated by the growth of a single bubble at the electrode at any one time. The transients in

P. Kristof; M. Pritzker

1997-01-01

405

Gas storage cylinder formed from a composition containing thermally exfoliated graphite  

NASA Technical Reports Server (NTRS)

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.

Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor)

2012-01-01

406

Gas and liquid permeation properties of modified interfacial composite reverse osmosis membranes  

Microsoft Academic Search

Gas permeation tests using nitrogen, oxygen, hydrogen, helium and carbon dioxide were performed to assess how membrane modification procedures affect the separating layer morphology of thin-film composite reverse osmosis membranes. Gas selectivity data provided evidence for the presence of nanoscale separating layer defects in dry samples of six commercial membrane types. These defects were eliminated when the membrane surface was

Jennifer S. Louie; Ingo Pinnau; Martin Reinhard

2008-01-01

407

Purification of synthesis gas and correction of its composition for obtaining liquid hydrocarbons  

NASA Astrophysics Data System (ADS)

Results from calculated and design works on elaborating stages through which synthesis gas used for producing liquid synthetic hydrocarbons is purified and refined are presented. Two stages of high-temperature desulfurization are used for removing sulfur from gas, and steam conversion is used for correcting its composition.

Epikhin, A. N.; Somov, A. A.

2011-06-01

408

Release and conversion of ammonia in bioreactor landfill simulators.  

PubMed

Bioreactor landfills are an improvement to normal sanitary landfills, because the waste is stabilised faster and the landfill gas is produced in a shorter period of time in a controlled way, thus enabling CH(4) based energy generation. However, it is still difficult to reach, within 30 years, a safe status of the landfill due to high NH(4)(+) levels (up to 3 g/L) in the leachate and NH(4)(+) is extremely important when defining the closure of landfill sites, due to its potential to pollute aquatic environments and the atmosphere. The effect of environmental conditions (temperature, fresh versus old waste) on the release of NH(4)(+) was assessed in experiments with bench (1 L) and pilot scale (800 L) reactors. The NH(4)(+) release was compared to the release of Cl(-) and BOD in the liquid phase. The different release mechanisms (physical, chemical, biological) of NH(4)(+) and Cl(-) release from the solid into the liquid phase are discussed. The NH(4)(+) level in the liquid phase of the pilot scale reactors starts decreasing after 100 days, which contrasts real-scale observations, where the NH(4)(+) level increases or remains constant. Based on the absence of oxygen in the simulators, the detectable levels of hydrazin and the presence of Anammox bacteria, it is likely that Anammox is involved in the conversion of NH(4)(+) into N(2). Nitrogen release was shown to be governed by physical and biological mechanisms and Anammox bacteria are serious candidates for the nitrogen removal process in bioreactor landfills. These results, combined with carbon removal and improved hydraulics, will accelerate the achievement of environmental sustainability in the landfilling of municipal solid waste. PMID:20884112

Lubberding, Henk J; Valencia, Roberto; Salazar, Rosemarie S; Lens, Piet N L

2012-03-01

409

Evaluation of methane emissions from Palermo municipal landfill: Comparison between field measurements and models  

SciTech Connect

Methane (CH{sub 4}) diffuse emissions from Municipal Solid Waste (MSW) landfills represent one of the most important anthropogenic sources of greenhouse gas. CH{sub 4} is produced by anaerobic biodegradation of organic matter in landfilled MSW and constitutes a major component of landfill gas (LFG). Gas recovery is a suitable method to effectively control CH{sub 4} emissions from landfill sites and the quantification of CH{sub 4} emissions represents a good tool to evaluate the effectiveness of a gas recovery system in reducing LFG emissions. In particular, LFG emissions can indirectly be evaluated from mass balance equations between LFG production, recovery and oxidation in the landfill, as well as by a direct approach based on LFG emission measurements from the landfill surface. However, up to now few direct measurements of landfill CH{sub 4} diffuse emissions have been reported in the technical literature. In the present study, both modeling and direct emission measuring methodologies have been applied to the case study of Bellolampo landfill located in Palermo, Italy. The main aim of the present study was to evaluate CH{sub 4} diffuse emissions, based on direct measurements carried out with the flux accumulation chamber (static, non-stationary) method, as well as to obtain the CH{sub 4} contoured flux map of the landfill. Such emissions were compared with the estimate achieved by means of CH{sub 4} mass balance equations. The results showed that the emissions obtained by applying the flux chamber method are in good agreement with the ones derived by the application of the mass balance equation, and that the evaluated contoured flux maps represent a reliable tool to locate areas with abnormal emissions in order to optimize the gas recovery system efficiency.

Di Bella, Gaetano, E-mail: dibella@idra.unipa.it [Dipartimento di Ingegneria Civile, Ambientale e Aerospaziale, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Di Trapani, Daniele, E-mail: ditrapani@idra.unipa.it [Dipartimento di Ingegneria Civile, Ambientale e Aerospaziale, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Viviani, Gaspare, E-mail: gviv@idra.unipa.it [Dipartimento di Ingegneria Civile, Ambientale e Aerospaziale, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy)

2011-08-15

410

Carbon nanotube\\/PMMA composite thin films for gas-sensing applications  

Microsoft Academic Search

The design and development of composite thin films of polymethylmethacrylate (PMMA) with multiwalled carbon nanotubes (CNTs) and surface-modified multiwalled carbon nanotubes (f-CNTs) for gas-sensing applications are presented in this paper. The responses of these composites for different organic vapors were evaluated by monitoring the change in the resistance of thin films of composite when exposed to gases like dichloromethane, chloroform,

Biju Philip; Jose K. Abraham; Anupama Chandrasekhar; Vijay K. Varadan

2003-01-01

411

Carbon black\\/polystyrene composites as candidates for gas sensing materials  

Microsoft Academic Search

Amorphous polymer-based composites consisting of polystyrene and carbon black were developed in the current work as candidates for gas sensing materials. With the help of polymerization filling, i.e., in-situ polymerization of styrene in the presence of carbon black, the composites were provided with low percolation threshold. The experimental results indicated that the composites have selective sensitivity as characterized by high

Jun Rong Li; Jia Rui Xu; Ming Qiu Zhang; Min Zhi Rong

2003-01-01

412

Effect of temperature variation and gas composition on the stability of the RPC operation  

NASA Astrophysics Data System (ADS)

An Inverted Double Gap Resistive Plate Chambers (RPC) made of bakelite of 5×10 9 ?cm volume resistivity was tested at avalanche rates up to 1 kHz/cm2/ gap in the Gamma Irradiation Facility at CERN in 2001. The inner surfaces of the chamber electrodes were cladded using linseed oil varnish. Dependence of the intrinsic RPC noise and the stability of the gas gain on the gas temperature and the gas composition are discussed.

?wiok, M.; Dominik, W.; Górski, M.; Królikowski, J.

2003-08-01

413

Effects of shielding gas composition and activating flux on GTAW weldments  

Microsoft Academic Search

This study investigated the effects of shielding gas composition and activating flux on weld morphology, angular distortion, retained delta-ferrite content, mechanical properties and hot cracking susceptibility. An autogenous gas tungsten arc welding process was used on austenitic stainless steel to produce a bead-on-plate weld. The nitrogen content in the argon-based shielding gas was in the range of 2.5–10vol.%. Activating flux

Her-Yueh Huang

2009-01-01

414

Slope stability of bioreactor landfills during leachate injection: effects of heterogeneous and anisotropic municipal solid waste conditions.  

PubMed

In bioreactor landfills, leachate recirculation can significantly affect the stability of landfill slope due to generation and distribution of excessive pore fluid pressures near side slope. The current design and operation of leachate recirculation systems do not consider the effects of heterogeneous and anisotropic nature of municipal solid waste (MSW) and the increased pore gas pressures in landfilled waste caused due to leachate recirculation on the physical stability of landfill slope. In this study, a numerical two-phase flow model (landfill leachate and gas as immiscible phases) was used to investigate the effects of heterogeneous and anisotropic nature of MSW on moisture distribution and pore-water and capillary pressures and their resulting impacts on the stability of a simplified bioreactor landfill during leachate recirculation using horizontal trench system. The unsaturated hydraulic properties of MSW were considered based on the van Genuchten model. The strength reduction technique was used for slope stability analyses as it takes into account of the transient and spatially varying pore-water and gas pressures. It was concluded that heterogeneous and anisotropic MSW with varied unit weight and saturated hydraulic conductivity significantly influenced the moisture distribution and generation and distribution of pore fluid pressures in landfill and considerably reduced the stability of bioreactor landfill slope. It is recommended that heterogeneous and anisotropic MSW must be considered as it provides a more reliable approach for the design and leachate operations in bioreactor landfills. PMID:24554462

Giri, Rajiv K; Reddy, Krishna R

2014-03-01

415

The carbon isotopic composition of catalytic gas: a comparative analysis with natural gas  

Microsoft Academic Search

The 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

Frank D Mango; L. W. Elrod

1999-01-01

416

Methane oxidation at a surface-sealed boreal landfill.  

PubMed

Methane oxidation was studied at a closed boreal landfill (area 3.9 ha, amount of deposited waste 200,000 tonnes) equipped with a passive gas collection and distribution system and a methane oxidative top soil cover integrated in a European Union landfill directive-compliant, multilayer final cover. Gas wells and distribution pipes with valves were installed to direct landfill gas through the water impermeable layer into the top soil cover. Mean methane emissions at the 25 measuring points at four measurement times (October 2005-June 2006) were 0.86-6.2 m(3) ha(-1) h(-1). Conservative estimates indicated that at least 25% of the methane flux entering the soil cover at the measuring points was oxidized in October and February, and at least 46% in June. At each measurement time, 1-3 points showed significantly higher methane fluxes into the soil cover (20-135 m(3) ha(-1) h(-1)) and methane emissions (6-135 m(3) ha(-1) h(-1)) compared to the other points (< 20 m(3) ha(-1) h(-1) and < 10 m(3) ha(-1) h(-1), respectively). These points of methane overload had a high impact on the mean methane oxidation at the measuring points, resulting in zero mean oxidation at one measurement time (November). However, it was found that by adjusting the valves in the gas distribution pipes the occurrence of methane overload can be to some extent moderated which may increase methane oxidation. Overall, the investigated landfill gas treatment concept may be a feasible option for reducing methane emissions at landfills where a water impermeable cover system is used. PMID:19264471

Einola, Juha; Sormunen, Kai; Lensu, Anssi; Leiskallio, Antti; Ettala, Matti; Rintala, Jukka

2009-07-01

417

Compositional Discrimination of Decompression and Decomposition Gas Bubbles in Bycaught Seals and Dolphins  

PubMed Central

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.

Bernaldo de Quiros, Yara; Seewald, Jeffrey S.; Sylva, Sean P.; Greer, Bill; Niemeyer, Misty; Bogomolni, Andrea L.; Moore, Michael J.

2013-01-01

418

Isotopic composition of gas hydrates in subsurface sediments from offshore Sakhalin Island, Sea of Okhotsk  

NASA Astrophysics Data System (ADS)

Hydrate-bearing sediment cores were retrieved from recently discovered seepage sites located offshore Sakhalin Island in the Sea of Okhotsk. We obtained samples of natural gas hydrates and dissolved gas in pore water using a headspace gas method for determining their molecular and isotopic compositions. Molecular composition ratios C1/C2+ from all the seepage sites were in the range of 1,500-50,000, while ?13C and ?D values of methane ranged from -66.0 to -63.2‰ VPDB and -204.6 to -196.7‰ VSMOW, respectively. These results indicate that the methane was produced by microbial reduction of CO2. ?13C values of ethane and propane (i.e., -40.8 to -27.4‰ VPDB and -41.3 to -30.6‰ VPDB, respectively) showed that small amounts of thermogenic gas were mixed with microbial methane. We also analyzed the isotopic difference between hydrate-bound and dissolved gases, and discovered that the magnitude by which the ?D hydrate gas was smaller than that of dissolved gas was in the range 4.3-16.6‰, while there were no differences in ?13C values. Based on isotopic fractionation of guest gas during the formation of gas hydrate, we conclude that the current gas in the pore water is the source of the gas hydrate at the VNIIOkeangeologia and Giselle Flare sites, but not the source of the gas hydrate at the Hieroglyph and KOPRI sites.

Hachikubo, Akihiro; Krylov, Alexey; Sakagami, Hirotoshi; Minami, Hirotsugu; Nunokawa, Yutaka; Shoji, Hitoshi; Matveeva, Tatiana; Jin, Young K.; Obzhirov, Anatoly

2010-06-01

419

Where Should the Landfill Go?  

ERIC Educational Resources Information Center

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)

Fazio, Rosario P.; McFaden, Dennis

1993-01-01

420

LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL  

SciTech Connect

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.

Don Augenstein

2001-02-01

421

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...

422

Gas sensors based on carbon nanoflake/tin oxide composites for ammonia detection.  

PubMed

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

Lee, Soo-Keun; Chang, Daeic; Kim, Sang Wook

2014-03-15

423

Modelling for environmental assessment of municipal solid waste landfills (part 1: hydrology).  

PubMed

A three-dimensional dynamic simulation program for the prediction of leachate flows, their organic contamination and the gas generated in municipal waste landfills, (MODUELO) has been developed. It permits the simulation of canyon