These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Evaluation of Landfill Gas Decay Constant for Municipal Solid Waste Landfills Operated as Bioreactors  

Microsoft Academic Search

Prediction of the rate of gas production from bioreactor landfills is important for the optimization of energy recovery and for estimating greenhouse gas emissions. To improve the predictability of gas production, landfill gas (LFG) composition and flow rates were monitored for 4 yr from one conventional and two bioreactor landfill cells at the Outer Loop Landfill in Louisville, KY. The

Thabet M. Tolaymat; Roger B. Green; Gary R. Hater; Morton A. Barlaz; Paul Black; Doug Bronson; Jon Powell; Darko Koracin; L.-W. Chen; David Dubois; Ramesh Vellore; John Watson; Naresh Kumar; Eladio Knipping; Neil Wheeler; Kenneth Craig; Stephen Reid; Douglas Lowenthal; Ta-Yuan Chang; Shen-Ju Lin; Ruei-Hao Shie; Shih-Wei Tsai; Hui-Tsung Hsu; Ching-Tsan Tsai; Hsien-Wen Kuo; Chow-Feng Chiang; Jim-Shoung Lai; Xiaosheng Qin; Guohe Huang; Lei Liu; Xiaohan Chen; Natalia Schmid; Lijuan Wang; Nigel Clark; Pablo Ruiz; Claudia Toro; Jorge Caceres; Gianni pez; Pedro Oyola; Petros Koutrakis

2010-01-01

2

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

EPA Science Inventory

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

3

Migrating landfill gas proves challenging  

SciTech Connect

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 Sharp Street. Three landfill gas wells were installed at the north corner of the landfill to control off-site migration of landfill gas. Landfill gas, through diffusion, saturates soil pores below and around the landfill. Groundwater serves as an effective barrier to landfill gas migration. Thus a rising water table mobilizes landfill gas from soil pores. Where that gas cannot be effectively collected, off-site migration will occur. The solution to ensuring public safety is to collect landfill gas on-site before it escapes the influence of gas collection wells. This may require complete reevaluation of an existing landfill gas collection system and potential renovation to collect greater quantities of land-fill gas. Cost-effective implementation of this strategy calls for two gas collection systems: one for collection of methane-rich landfill gas for electrical generation and resource recovery, and the other to control off-site migration of landfill gas through on-site combustion. Installation/upgrades of the foregoing solutions are long-term options. For the short-term immediate mitigation of high landfill gas migration, installation of a passive vent system was necessary with the option of active extraction. However, one must recognize that the public is ultimately better served by controlling landfill gas on-site before it approaches dangerous off-site levels.

Dobrowolski, J.G.; Dellinger, A.S. [City of Los Angeles Bureau of Sanitation, CA (United States)

1994-12-01

4

Evolution on qualities of leachate and landfill gas in the semi-aerobic landfill  

Microsoft Academic Search

To study the characteristics of stabilization in semi-aerobic landfill, large-scale simulated landfill was constructed based on the semiaerobic landfill theory. Consequently, the concentrations of chemical oxygen demand (COD), ammonia nitrogen, and nitrite nitrogen, and the pH value in leachate, as well as the component contents of landfill gas composition (methane, carbon dioxide, and oxygen) in landfill were regularly monitored for

Qifei HUANG; Yufei YANG; Xiangrui PANG; Qi WANG

2008-01-01

5

Landfill Settlement with Decomposition and Gas Generation  

Microsoft Academic Search

A one-dimensional multiphase numerical model is developed to simulate the vertical settlement involving liquid and gas flows in a deformable settling municipal solid waste MSW landfill. MSW is represented by a chemical composition, and a global stoichio- metric reaction is used to estimate the maximum yield of gas generation. Following the general assumption accepted in the literature, the gas generated

Ertan Durmusoglu; M. Yavuz Corapcioglu

2005-01-01

6

Leachate evaporation using landfill gas  

Microsoft Academic Search

This paper describes a century-old technology with a new twist of using landfill gas as a fuel in an evaporation system. The system is designed to help landfills reduce the cost of leachate disposal while also destroying VOC emissions in an enclosed flare.

T. M. White; V. M. Grace; W. Freivald

1996-01-01

7

Landfill Gas Effects on Evapotranspirative Landfill Covers  

Microsoft Academic Search

The performance of an evapotranspirative landfill cover can be adversely affected by transport of landfill gases to the plant root zone. Healthy plant communities are critical to the success and effectiveness of these vegetated landfill covers. Poor vegetative cover can result in reduced transpiration, increased percolation, and increased erosion regardless of the thickness of the cover. Visual inspections of landfill

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

2005-01-01

8

LATERAL LANDFILL GAS MIGRATION: CHARACTERIZATION AND  

E-print Network

LATERAL LANDFILL GAS MIGRATION: CHARACTERIZATION AND PRELIMINARY MODELING RESULTS O.BOUR*, E,UniversitéLaval, Sainte-Foy, Canada SUMMARY: Lateral landfill gas migration occurs in the surroundings of a MSW landfill complementary physical measures were used to build a conceptual model of lateral landfill gas migration

Boyer, Edmond

9

Landfill course: managing gas and leachate production on landfills  

Microsoft Academic Search

Controlling gas and leachate production is a primary objective of sound landfill management. Gases, composed mainly of carbon dioxide and methane, are formed during the decomposition of solid wastes. Leachate forms as water passes through the refuse, dissolving out chemicals. Three basic methods for controlling gas and leachate production are presented: managing production; directing gas or leachate movement; and treating

Reinfl

1977-01-01

10

Demonstration of landfill gas enhancement techniques in landfill simulators  

NASA Astrophysics Data System (ADS)

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

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

1982-02-01

11

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 9.50.4mg/m(3) total siloxanes, majority of which were octamethylcyclotetrasiloxane (D4) (5.00.2mg/m(3)), decamethylcyclopentasiloxane (D5) (2.90.1mg/m(3)) and hexamethyldisiloxane (L2) (1.60.1mg/m(3)). The samples collected from the engine heads before the activated carbon treatment of LFG had significantly high levels of silicon (149,40089,900mg/kg) as well as calcium (70,84017,750mg/kg), sulfur (42,50011,500mg/kg), and zinc (22,3007200mg/kg). After the activated carbon treatment, silicon levels decreased significantly; however, deposits had higher sulfur content (104,56068,100mg/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

12

LANDFILL GAS PRETREATMENT FOR FUEL CELL APPLICATIONS  

EPA Science Inventory

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

13

LANDFILL GAS ENERGY UTILIZATION: TECHNOLOGY OPTIONS AND CASE STUDIES  

EPA Science Inventory

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

14

Fuel cell energy recovery from landfill gas  

NASA Astrophysics Data System (ADS)

Phase 1 results are discussed of an EPA sponsored program to show energy recovery from landfill gas using a commercial phosphoric acid fuel cell power plant. EPA is interested in fuel cells for the application because it is the cleanest energy conversion technology available. Phase 1 is a conceptual design, cist, and evaluation study. The conceptual design of the fuel energy recovery concept is described and its economic and environmental feasibility is projected. Phase 2 covers the construction and testing of a landfill gas pretreatment system which will render landfill gas suitable for use in the fuel cell. Phase 3 is the demonstration of the energy recovery concept.

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

15

Policy Analysis Landfill-Gas-to-Energy Projects  

E-print Network

organic compounds) have to collect and combust the landfill gas. Traditionally these landfills have flared the gas to comply with the standards. A flare is a device that burns the landfill gas to reduce odors, safety concerns, and methane emissions. An alternative to flaring is using the landfill gas to generate

Jaramillo, Paulina

16

Gas generation, transport, and extraction in landfills  

Microsoft Academic Search

A model describing the generation, transport, and extraction of gas in a landfill has been developed. In the model the landfill gas is assumed to be an equimolar mixture of CH[sub 4] and CO[sub 2]. The waste is thought to comprise three classes of materials differing in their degree of biodegradability but all following first-order biodegradation kinetics. The model describes

Sumadhu G. Arigala; Theodore T. Tsotsis; Y. C. Yortsos; J. J. Kattapuram; I. A. Webster

1995-01-01

17

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

18

Landfill-gas energy utilization: Technology options and case studies. Final report, Mar 91-Mar 92  

SciTech Connect

The report discusses technical, environmental, and other issues associated with using landfill gas as fuel, and presents case studies of projects in the U.S. illustrating some common energy uses. The full report begins by covering basic issues such as gas origin, composition, and means of collection; environmental and regulatory background is presented. Properties of landfill gas as a fuel are reviewed; equipment that can utilize landfill gas is discussed. The report then describes experience with six projects in the U.S. where landfill gas has been used for energy. It also references literature on other landfill gas energy projects of interest. Conclusions regarding uses of landfill gas for energy are presented.

Augenstein, D.; Pacey, J.

1992-06-01

19

Passive drainage and biofiltration of landfill gas: Australian field trial  

SciTech Connect

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

Dever, S.A. [School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia) and GHD Pty. Ltd., 10 Bond Street, Sydney, NSW 2000 (Australia)]. E-mail: stuart_dever@ghd.com.au; Swarbrick, G.E. [School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)]. E-mail: g.swarbrick@unsw.edu.au; Stuetz, R.M. [School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)]. E-mail: r.stuetz@unsw.edu.au

2007-07-01

20

Fuel cell energy recovery from landfill gas  

NASA Astrophysics Data System (ADS)

International Fuel Cells Corporation is conducting a US Environmental Protection Agency (EPA) sponsored program to demonstrate energy recovery from landfill gas using a commercial phosphoric acid fuel cell power plant. The US EPA is interested in fuel cells for this application because it is the cleanest energy conversion technology available. This paper discusses the results of Phase I, a conceptual design, cost, and evaluation study. The conceptual design of the fuel cell energy recovery concept is described and its economic and environmental feasibility is projected. Phase II will include construction and testing of a landfill gas pretreatment system which will render landfill gas suitable for use in the fuel cell. Phase III will be a demonstration of the energy recovery concept.

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

21

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

22

Combining systems for leachate recirculation and landfill gas collection  

Microsoft Academic Search

To move landfill bioreactor treatment systems from the experimental level to viable landfill operations across the country, alternative methods must be designed, operated and proven at full-scale landfills. The system installed at the Alachua County Southwest Landfill in Florida was originally designed for leachate injection alone, but was successfully converted to a combined system for gas and leachate management after

T. G. Townsend; W. L. Miller; R. A. Bishop; J. H. Carter

2009-01-01

23

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

24

Soil gas investigations at the Sanitary Landfill  

SciTech Connect

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

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

1992-07-01

25

Soil gas investigations at the Sanitary Landfill  

SciTech Connect

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

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

1992-07-01

26

Management of gas and leachate in landfills  

Microsoft Academic Search

The symposium proceedings are primarily intended to disseminate up-to-date information on extramural research on gas and leachate formation, collection and management in sanitary landfills funded by the Solid and Hazardous Waste Research Division (SHWRD), US Environmental Protection Agency, Municipal Environmental Research Laboratory in Cincinnati, Ohio. Selected papers from work of other organizations were included in the symposium to identify closely

1977-01-01

27

FUEL CELL ENERGY RECOVERY FROM LANDFILL GAS  

EPA Science Inventory

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

28

Controls on Landfill Gas Collection Efficiency: Instantaneous and Lifetime Performance  

Microsoft Academic Search

Estimates of landfill gas (LFG) collection efficiency are required to estimate methane emissions and the environmental performance of a solid waste landfill. The gas collection efficiency varies with time on the basis of the manner in which landfills are designed, operated, and regulated. The literature supports instantaneous collection efficiencies varying between 50% and near 100%, dependent on the cover type

Morton A. Barlaz; Jeff P. Chanton; Roger B. Green; Hulda Winnes; Erik Fridell; Junyu Zheng; Wenwei Che; Xuemei Wang; Peter Louie; Liuju Zhong; Elizabeth Vega; Douglas Lowenthal; Hugo Ruiz; Elizabeth Reyes; John Watson; Judith Chow; Mar Viana; Xavier Querol; Andres Alastuey; Mark Gibson; Mathew Heal; David Bache; Andrew Hursthouse; Iain Beverland; Susanne Craig; Colin Clark; Mike Jackson; Nicholas Nussbaum; Dongzi Zhu; Hampden Kuhns; Claudio Mazzoleni; M.-C. Chang; Hans ller; David Sodeman; Sebastian Uppapalli; Melanie Sattler; Divya Garrepalli; Chandraprakash Nawal; Daniel Burgard; Melissa Provinsal; Lien-Te Hsieh; Ya-Fen Wang; Gia-Hao Kuo; Lin-Chi Wang; Guo-Ping Chang-Chien; Pedro Sanhueza; Monica Torreblanca; Luis Diaz-Robles; L. Schiappacasse; Maria Silva; Teresa Astete

2009-01-01

29

FIRST ORDER KINETIC GAS GENERATION MODEL PARAMETERS FOR WET LANDFILLS  

EPA Science Inventory

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

30

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...

31

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

32

Landfill Gas Effects on Vegetation and on Water Balance  

Microsoft Academic Search

Landfill gas (LFG) inhibits plant growth on landfill covers. Well-established plant growth and deep root penetration are critical to the success and effectiveness of vegetated landfill covers. Poor vegetative stands can result in reduced transpiration, increased percolation, and increased erosion regardless of the thickness of the cover. Therefore, it is important to evaluate the potential effects LFG may have on

Mark D. Ankeny; Gregory J. Stormberg

33

New Financing Options and Incentives for Landfill Gas Energy  

Microsoft Academic Search

Stakeholders promoting landfill gas (LFG) energy projects are identifying new funding incentives to implement LFG energy (LFGE) projects. This article focuses on how landfills are participating in voluntary carbon and renewable energy markets, and presents case studies from award-winning projects that utilize these funding mechanisms.Landfills participate in the voluntary carbon markets using one of two main mechanisms: on an exchange

Chris Godlove; Amanda R. Singleton

2010-01-01

34

Landfill gas energy recovery: Turning a liability into an asset  

SciTech Connect

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

Nichols, M. [EPA, Washington, DC (United States)

1996-08-01

35

Capture and Utilisation of Landfill Gas  

E-print Network

about 955 landfills that recovered biogas. The largest number of such landfills were in the USA landfills in Denmark that in total captured 5,800Nm3 of biogas per hour, equivalent to 276.4MW of contained #12;Biomass US DATA ON GENERATION OF BIOGAS AT LANDFILLS Eileen Berenyi, a Research Associate of EEC

Columbia University

36

Gas production and migration in landfills and geological materials.  

PubMed

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. PMID:11695741

Nastev, M; Therrien, R; Lefebvre, R; Glinas, P

2001-11-01

37

Microbial mitigation of greenhouse gas emissions from landfill cover soils  

NASA Astrophysics Data System (ADS)

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 proposed to stimulate methanotrophs, a group of bacteria that consume methane, in the cover soil to prevent fugitive methane emissions. Several factors, however, must be addressed to make such a biogenic removal mechanism effective. First, methanotrophic activity can be inhibited by nonmethane organic compounds (NMOCs) that are commonly found in landfill soil gas. Second, although methanotrophs can be easily stimulated with the addition of nitrogenous fertilizers, biogenic production of nitrous oxide with a GWP 296 times higher than that of carbon dioxide, is also stimulated. To consider these issues, two general areas of research were performed. First, a dimensionless number was developed based on Michaelis-Menten kinetics that describes the effects of the presence of multiple NMOCs on methanotrophic growth and survival. This model was validated via experimental measurements of methanotrophic growth in the presence of varying amounts of NMOCs. Second, the effects of nutrient amendments on methane oxidation and nitrous oxide production were examined by constructing soil microcosms using landfill cover soils. Here, it was shown that the addition of ammonium in the presence of phenylacetylene stimulated methane oxidation but inhibited nitrous oxide production. Furthermore, to understand the methanotrophic community structure and activity in response to these amendments, DNA microarray and transcript analyses were performed. The results indicated the predominance of Type II methanotrophs but that Type I methanotrophs responded more significantly to these amendments. Also, substantial activity of pMMO-expressing methanotrophs was observed, suggesting that these methanotrophs were responsible for nitrous oxide production. Collectively, these data demonstrate that methanotrophic activity and community structure can be differentially affected by both landfill gas composition and amendments, thus providing insights as how best to manipulate methanotrophic processes to better mitigate greenhouse gas emissions.

Lee, Sung-Woo

38

Model to aid the design of composite landfill liners  

E-print Network

33 37 37 LIST OF FIGURES Figure Page 1 Schematic of a Composite Liner and Leachate Collection System 2 Sources of Leachates that Contact Landfill Liners 3 Layout of the Volatile Extraction Subsystem 4 Nodes, Potentials and Fluxes Diagram... and range in size from a few acres to hundreds of acres. Fig. 1 depicts a simplified schematic of a hazardous waste landfill, showing the geometry and placement of double liners and leachate collection systems in a landfill. The diagram shows leachate...

Mohammed, Kifayathulla

2012-06-07

39

TEST RESULTS FOR FUEL-CELL OPERATION ON LANDFILL GAS  

EPA Science Inventory

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

40

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

41

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

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

Horizontal collectors for landfill gas collection and migration control  

SciTech Connect

Landfill owners and operators are forever challenged with properly managing landfill gas (LFG). Collecting this LFG has evolved into an art, as well as a science. Technical expertise and sheer creativity complementary skills required to successfully manage both LFG collection and migration. The vertical LFG collection well has been an essential component for landfill owners and operators for over three decades. They have proved troublesome, however, for active landfill owners who attempt to collect LFG from the midst of an active site-the vertical wells prove more a {open_quotes}target{close_quotes} for refuse collection vehicles disposing their load, than for effective, long term LFG collection. Active and inactive/closed landfill owners must also contend with LFG migration at or near the refuse boundary. Multiple vertical LFG wells must be used to control LFG migration and surface emissions. Vertical LFG wells do work, but at significant expense of the landfill owner. In the past 10 years, the use of horizontal LFG wells or collectors has gained momentum, both for effectiveness and cost. The City of Los Angeles, Bureau of Sanitation operates one active Class III landfill and manages five closed Class III landfills. At Lopez Canyon Landfill (active), horizontal LFG collection wells were installed as early as 1987, for LFG collection. At Toyon Canyon Landfill (closed), horizontal collection wells were installed in 1992 and 1994 for LFG migration and surface emissions control.

Dobrowski, J.G. [Constantin Pano, Los Angeles, CA (United States)

1995-08-01

44

Mercury emissions as landfill gas from a large-scale abandoned landfill site in Seoul  

NASA Astrophysics Data System (ADS)

The composition of landfill gas (LFG) was analyzed for vapor-phase mercury (Hg) (primarily in its elemental form, Hg 0) and relevant environmental parameters from 42 out of 106 ventpipes placed across two different sectors of the Nan-Ji-Do (NJD) landfill site in Seoul, Korea during September/October 2000. Results of our studies showed that large quantities of Hg emanated through these ventpipes which were infiltrated deep into the waste layer. The mean concentration of Hg, computed using the data sets collected from 42 ventpipes, was 420 ng m -3 with a range of 3.45-2952 ng m -3. Because large differences were apparent in its concentration levels not only between the two sectors of 1 and 2 but also between the plain and slope areas, evaluation of the data was made by dividing them into four different categories, namely plain areas of sectors 1 and 2 and slope areas of sectors 1 and 2. By categorizing the data in such a manner, the emission fluxes of ventilated Hg were estimated for each data group at the NJD site. The flux values of Hg for each data group were distinguished so that the enhanced fluxes were observed in plain compared to slope areas. The computed LFG fluxes of Hg from the whole NJD site were on the order of 23 g on an annual basis. The overall results of our study suggest that the vent emission of Hg from the study site is comparable in magnitude to those reported previously (e.g., the Florida landfill sites in US), while the LFG emissions of Hg may not necessarily be the most dominant source in the NJD site.

Kim, Ki-Hyun; Kim, Min-Young

45

LANDFILL GAS ENERGY UTILIZATION: TECHNICAL AND NON-TECHNICAL CONSIDERATIONS  

EPA Science Inventory

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

46

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

47

Landfill gas-fired power plant pays cost of operating landfill  

SciTech Connect

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 much more stringent and costly. Palos Verdes landfill, owned jointly by the Los Angeles County Sanitation Districts and Los Angeles County, is located about three miles from the Pacific Ocean in the city of Rolling Hills Estates, Calif. The landfill was closed in 1980. The garbage was covered with six to eight feet of soil, and the area was landscaped. Part of this area has already been developed as the South Coast Botanical Gardens and Ernie Howlett Park. The remainder is scheduled to become a golf course. As refuse decays within a landfill, the natural anaerobic biological reaction generates a low-Btu methane gas along with carbon dioxide, known as landfill gas (LFG). The gas also contains other less desirable trace components generated by the decomposing garbage. Uncontrolled, these gases migrate to the surface and escape into the atmosphere where they generate environmental problems, including objectionable odors. The Sanitation Districts have installed a matrix of gas wells and a gas collection system to enable incineration of the gas in flares. This approach reduced aesthetic, environmental and safety concerns. However, emissions from the flares were still a problem. The Sanitation Districts then looked at alternatives to flaring the gas, one of which was electrical generation. Since the Sanitation Districts have no on-site use for thermal energy, power generation for use in the utility grid was deemed the most feasible alternative.

Wallace, I.P.

1991-01-01

48

Gas emissions from biodegradable waste in United Kingdom landfills.  

PubMed

The aim of this research was to predict the effect that the biodegradable municipal waste (BMW) diversion targets in the European Union landfill directive (99/31/EC) would have on landfill gas emissions. This is important for continued mitigation of these emissions. Work was undertaken in three stages using the GasSim model (v1.03) developed by the Environment Agency (England and Wales). The first stage considered the contribution to gas emissions made by each biodegradable component of the waste stream. The second stage considered how gas emissions from a landfill accepting biodegradable wastes with reduced biodegradable content would be affected. The third stage looked at the contribution to gas emissions from real samples of biologically pretreated BMW. For the first two stages, data on the waste components were available in the model. For the third stage samples were obtained from four different biological treatment facilities and the required parameters determined experimentally. The results of stage 1 indicated that in the first 15 years of the landfill the putrescible fraction makes the most significant contribution, after which paper/card becomes the most significant. The second stage found that biodegradability must be reduced by at least 60% to achieve a reduction in overall methane generation. The third stage found that emissions from samples of biologically pretreated BMW would result in a significant reduction in gas emissions over untreated waste, particularly in the early stage of the landfill lifetime; however, low level emissions would continue to occur for the long term. PMID:21088129

Donovan, Sally Maree; Jilang Pan; Bateson, Thomas; Gronow, Jan R; Voulvoulis, Nikolaos

2011-01-01

49

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

EPA Science Inventory

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

50

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; Stense, Steen; Christensen, Thomas H

2011-07-01

51

UPDATE OF EPA'S EMISSION FACTORS FOR LANDFILL GAS EMISSIONS  

EPA Science Inventory

The paper describes an effort to collect updated data and determine if changes are needed to AP-42, a document that provides emission factors characterizing landfill gas (LFG) emissions from sites with and without LFG controls. The work underway includes the types of measurement ...

52

EMERGING TECHNOLOGIES FOR THE MANAGEMENT AND UTILIZATION OF LANDFILL GAS  

EPA Science Inventory

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

53

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 O, N, and HO. 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

54

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...

55

FUEL CELL OPERATION ON LANDFILL GAS AT PENROSE POWER STATION  

EPA Science Inventory

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

56

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

57

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

58

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. 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

59

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

60

Field Practices Installation and operations of a landfill gas collection and flare system  

SciTech Connect

The Sheldon-Arleta Landfill was operated by the City of Los Angeles from 1962 until 1974. Refuse was landfilled in what was formerly a quarry pit and placed prior to development and use of clay and synthetic liner materials. This paper is a continuance of the paper presented at the 17th Annual Landfill Gas Symposium-identifying sources and causes of landfill gas migration hazards, the design for their remediation, and the field construction/implementation of those designs to remediate landfill gas migration hazards.

Dellinger, A.S.; Greeb, K.W. [Bureau of Sanitation, Los Angeles, CA (United States)

1995-08-01

61

Application of landfill gas as a liquefied natural gas fuel for refuse trucks in Texas  

E-print Network

apparent negative impacts of these conventional fuels are global warming, poor air-quality, and adverse health effects. Considering these negative impacts, it is necessary to develop and use non-conventional sources of energy. Landfill gas (LFG) generated...

Gokhale, Bhushan

2007-04-25

62

Environmental assessment and sustainable management options of leachate and landfill gas treatment in Estonian municipal waste landfills  

Microsoft Academic Search

Purpose The purpose of this paper is to compare various landfill gas (LFG) and leachate treatment technologies in a life-cycle perspective. Design\\/methodology\\/approach Since a landfill causes emissions for a very long-time period, life-cycle-based environmental assessment was carried out to compare different technological options for sustainable leachate treatment and LFG collection and utilization. WAMPS, the life-cycle assessment (LCA) model

Viktoria Voronova; Harri Moora; Enn Loigu

2011-01-01

63

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

NASA Astrophysics Data System (ADS)

The bioreactor/ enhanced leachate recirculated (ELR) landfill operation with the addition of moisture/ leachate to the landfill, accelerate the process of landfill waste decomposition; and increase the generation of LFG over a shorter period of time. Since emissions from the landfills are directly related to the gas generation, the increase in gas generation might also increase the emission from the landfill. On the contrary, the presence of gas extraction is suggested to mitigate the fugitive emissions from the landfills. Therefore, the motivation of the current study was to evaluate the effect of ELR operation as well as the gas extraction on the greenhouse gas emissions from the landfill. The current study was conducted in the City of Denton Landfill, Texas. Methane emission was investigated using a portable FID and static flux chamber technique from the landfill surface. Emission was measured from an ELR operated cell (cell 2) as well as a conventional cell (cell 0) in the City of Denton Landfill. Methane emission for cell 2 varied from 9544.3 ppm to 0 ppm while for cell 0, it varied from 0 ppm to 47 ppm. High spatial variations were observed during monitoring from both cells 0 and cell 2 which could be recognized as the variation of gas generation below the cover soil. The comparison between emissions from the slope and surface of the landfill showed that more methane emission occurred from the slopes than the top surface. In addition, the average landfill emission showed an increasing trend with increase in temperature and decreasing trend with increasing precipitation. The effect of ELR operation near the recirculation pipes showed a lag period between the recirculation and the maximum emission near the pipe. The emission near the pipe decreased after 1 day of recirculation and after the initial decrease, the emission started to increase and continued to increase up to 7 days after the recirculation. However, approximately after 10 days of recirculation, the emission resumed its original state before the recirculation. It should be noted that the change in emission was only limited near the pipe. No overall change in emission was observed from the cell due to the recirculation. The comparison between the emissions from the conventional and ELR cell showed an overall higher emission from the ELR cell which could be attributed to the overall higher gas generation from the ELR cell as well. The gas extraction had a direct impact on emission, the emission dropped substantially right after the gas extraction from the landfill. However, the gas was extracted once in a month and comparison with the amount of gas extraction and emission showed that the emission decreased as the gas extraction increased. An attempt was made to incorporate the effect of ELR operation and the gas extraction in the estimating the methane emission from the landfills. Multiple linear regression (MLR) model was developed using the statistical tool SAS. The developed model was validated and the model showed an excellent agreement between the predicted emission and the measured emission from the landfills (average variation 9.6%).

Samir, Sonia

64

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

PubMed

Electricity generation and greenhouse gas (GHG) reductions were researched by making comparisons between municipal solid waste (MSW) landfill and incineration systems with three different electricity generation efficiencies - 10%, 21%, and 24.7%. For MSW landfill systems, it is shown that the total electricity generation is 198,747 MWh, and the total GHG emission reduction is 1,386,081 tonne CO( 2) during a 21-year operation period. For incineration systems, the total electricity generation is 611,801 MWh, and the total GHG emission reduction is 1,339,158 tonne CO(2) during a 10-year operation period even if the electricity generation efficiency is only 10%. It is also shown that electricity generation increases quicker than the GHG emission reductions with the increase of electricity generation efficiency. However, incineration systems show great superiority in LFG utilisation and GHG emission reductions. PMID:20124321

Haibin Han; Jisheng Long; Shude Li; Guangren Qian

2010-04-01

65

LANDFILL-GAS-TO-ENERGY PROJECTS: AN ANALYSIS OF NET PRIVATE AND SOCIAL BENEFITS  

E-print Network

: Emissions and Valuations from West County Landfill WEST COUNTY Uncontrolled Flare IC Engine Gas Turbine Landfill MODERN Uncontrolled Flare IC Engine Gas Turbine Steam Turbine Average Annual Methane Emissions Uncontrolled Flare IC Engine Gas Turbine Steam Turbine Average Annual Methane Emissions (tons) 19,284 2,893 2

Jaramillo, Paulina

66

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

SciTech Connect

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.

Not Available

1982-10-01

67

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

68

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

EPA Science Inventory

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

69

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

70

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

Microsoft Academic Search

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

Jenia A. McBrian Tufts; Jacky A. Rosati

2012-01-01

71

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

EPA Science Inventory

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

72

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

73

LEACHATE COLLECTION AND GAS MIGRATION AND EMISSION PROBLEMS AT LANDFILLS AND SURFACE IMPOUNDMENTS  

EPA Science Inventory

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 literature and information ob...

74

GUIDANCE FOR EVALUATING LANDFILL GAS EMISSIONS FROM CLOSED OR ABANDONED FACILITIES  

EPA Science Inventory

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

75

Computer simulation of gas generation and transport in landfillsI: quasi-steady-state condition  

Microsoft Academic Search

We develop a comprehensive three-dimensional (3D) model of gas generation and transport in landfills. The model, which is developed for a four-component gas mixture, takes into account the effect of heterogeneity in the distributions of the permeability and porosity in the landfill, as well as that of the soil that surrounds it. It also takes into account the presence of

Mehrdad Hashemi; Halil I. Kavak; Theodore T. Tsotsis; Muhammad Sahimi

2002-01-01

76

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

SciTech Connect

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

Morford, K.L. [Public Works, Glendale, CA (United States)

1995-08-01

77

[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

78

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

PubMed

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

Gajski, Goran; Ore?anin, Vinja; Garaj-Vrhovac, Vera

2012-04-01

79

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

80

Converting landfill gas to vehicle fuel: The results of over 30 months of operation  

SciTech Connect

The Sanitation Districts of Los Angeles County (Districts) have successfully converted landfill gas to vehicle fuel for over 30 months with the Clean Fuels facility (Clean Fuels). The station has a design capacity equivalent to 1,000 gallons of gasoline per day. The Districts utilize the compressed landfill gas (CLG) produced at the station to run a fleet of 13 vehicles, ranging from passenger vans to large on-road tractors. This paper presents information on the operation, maintenance, theory, and economics of converting landfill gas to vehicle fuel. The compressed natural gas (CNG) industry is expanding rapidly. The US Department of Energy projects the number of natural gas vehicles (NGVs) to grow from 66,000 in 1995 to 85,000 in 1996. A variety of CNG-powered refuse collection vehicles are now available from original equipment manufacturers (OEMs). Many industry pundits predict that refuse trucks will be the next major vehicle group after transit buses to convert to CNG. CNG provides the benefit of lower emissions than diesel and gasoline, with typical fuel costs of only 70 to 80 percent of the price of gasoline at retail pumps. The primary economic advantage of CNG over conventional fuels is its tax rate, which can be lower by about $0.30 per gallon of diesel equivalent. The CNG market may offer the landfill gas industry the same opportunity the electrical generation market offered in the 1980s. The Clean Fuels facility is located within the Districts` Puente Hills Landfill complex. Puente Hills is a very large landfill with over 70 million tons of refuse in place. The current fill rate is approximately 10,000 tons per day. The landfill gas flow rate is approximately 27,000 standard cubic feet per minute (scfm) at 42 percent methane.

Wheless, E.; Cosulich, J.; Wang, A.

1996-11-01

81

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

82

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

Galowitz, Stephen

2012-12-31

83

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

NASA Astrophysics Data System (ADS)

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

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

84

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

85

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

EPA Science Inventory

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

86

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

EPA Science Inventory

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

87

Evaluation test on a landfill gas-fired flare at the Los Angeles County Sanitation District's Puente Hills Landfill Facility  

SciTech Connect

A cooperative test program was conducted from February 18 through February 21, 1986, by Air Resources Board (ARB) and South Coast Air Quality Management District (SCAQMD) staff to evaluate the gaseous constituents from untreated landfill gas used to fuel a flare at the County of Los Angeles Sanitation District's Puente Hills Landfill. The flare was fueled with gases generated by the anaerobic decomposition of buried refuse. Emissions of criteria pollutants as determined from ARB test data and mass flow rates and Destruction and Removal Efficiencies (DRE) of non-criteria pollutant compounds determined at the stack from SCAQMD test data are presented. Mass-flow rates and DREs for chlorinated and aromatic compounds determined from data from ARB resin samples are presented. Destruction and removal efficiencies based on mass flow rates for chlorinated compounds ranged from 35 to 99+ percent and for aromatic compounds ranged from four to 99+ percent. Dioxins, furans, and polychlorinated biphenyls were not detected in the inlet nor the outlet gas-stream samples.

Not Available

1986-07-01

88

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

PubMed

Hydrogen sulphide (H2S) gas is a major odorant at municipal landfills. The gas can be generated from different waste fractions, for example demolition waste containing gypsum based plaster board. The removal of H2S from landfill gas was investigated by filtering it through mineral wool waste products. The flow of gas varied from 0.3 l/min to 3.0 l/min. The gas was typical for landfill gas with a mean H2S concentration of ca. 4500 ppm. The results show that the sulphide gas can effectively be removed by mineral wool waste products. The ratios of the estimated potential for sulphide precipitation were 19:1 for rod mill waste (RMW) and mineral wool waste (MWW). A filter consisting of a mixture of MWW and RMW, with a vertical perforated gas tube through the center of filter material and with a downward gas flow, removed 98% of the sulfide gas over a period of 80 days. A downward gas flow was more efficient in contacting the filter materials. Mineral wool waste products are effective in removing hydrogen sulphide from landfill gas given an adequate contact time and water content in the filter material. Based on the estimated sulphide removal potential of mineral wool and rod mill waste of 14 g/kg and 261 g/kg, and assuming an average sulphide gas concentration of 4500 ppm, the removal capacity in the filter materials has been estimated to last between 11 and 308 days. At the studied location the experimental gas flow was 100 times less than the actual gas flow. We believe that the system described here can be upscaled in order to treat this gas flow. PMID:24140376

Bergersen, Ove; Haarstad, Ketil

2014-01-01

89

Demonstration of fuel cells to recover energy from landfill gas: Conceptual study  

NASA Astrophysics Data System (ADS)

Discussed here are the results of a conceptual design, cost, and evaluation study of energy recovery from landfill gas using a commercial phosphoric acid fuel cell power plant. The conceptual design of the fuel cell energy recovery system is described, and its economic and environmental feasibility is projected. A conceptual design of the project demonstration was established from the commercial system conceptual design. Key demonstration issues facing commercialization of the concept are addressed. Candidate demonstration sites were evaluated, which led to selection and EPA approval of the demonstration site. A plan is discussed for the construction and testing of a landfill gas pretreatment system which will render landfill gas suitable for use in the fuel cell. The final phase of the study will be a demonstration of the energy recovery concept.

Sandelli, G. J.

1992-01-01

90

CRITICAL REVIEW AND SUMMARY OF LEACHATE AND GAS PRODUCTION FROM LANDFILLS  

EPA Science Inventory

A Cooperative Agreement between the Municipal Environmental Research Laboratory and the Georgia Institute of Technology was established in 1983 to provide an evaluation of the state-of-the-art in municipal waste, landfill leachate and gas management. Summaries of full-scale and e...

91

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

EPA Science Inventory

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

92

Landfill gas as an energy resource: past, present and indications for the future  

Microsoft Academic Search

Landfill gas has proven to be a cost-effective, economic energy resource. To date utilization schemes have been recorded in 20 countries worldwide, producing a total resource of over 2 million tonnes of coal equivalent per annum (mtcepa). In the UK savings are currently estimated to be in the region of 120,000 tcepa. This paper discusses the trends which have resulted

P. S. Lawson

1989-01-01

93

IEA-Renewable Energy Technologies, Bioenergy Agreement Task 37: Energy from Biogas and Landfill Gas  

E-print Network

EFP-06 IEA- Renewable Energy Technologies, Bioenergy Agreement Task 37: Energy from Biogas-Bioenergy, Task 37- Energy from Biogas and Landfill Gas", via samarbejde, informationsudveksling, fælles analyser. biogas fra anaerob udrådning (AD) som en integreret gylle og affalds behandlings teknologi. Arbejdet

94

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

EPA Science Inventory

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

95

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

PubMed

Performances of gas engines operated with landfill gas (LFG) are affected by the impurities in the LFG, reducing the economic viability of energy recovery. The purpose of this study was to characterize the trace compounds in the LFG at the Odayeri Landfill, Istanbul, Turkey which is used for energy recovery. Composite gas samples were collected and analyzed for trace compounds (hydrocarbons, siloxanes, and volatile halogenated hydrocarbons) over a 3-year period. Trace compounds entering the gas engines, their impact on the engine performance were evaluated. The operational problems included deposit formation in the combustion chamber, turbocharger, and intercooler of engine before the scheduled maintenance times. High levels of hydrogen sulfide, as well as chlorinated and fluorinated compounds cause corrosion of the engine parts and decrease life of the engine oils. Persistence of siloxanes results in deposit formation, increasing engine maintenance costs. Pretreatment of LFG is necessary to protect the engines at the waste-to-energy facilities with persistence levels of siloxanes and volatile halogenated hydrocarbons. PMID:23063306

Sevimo?lu, Orhan; Tansel, Berrin

2013-01-01

96

Soil-gas survey at the solid waste landfill - Final Report  

SciTech Connect

A soil-gas survey to determine the lateral distribution of chlorinated hydrocarbon solvents in the vadose zone, and possibly ground water, was conducted at the Hanford Site Solid Waste Landfill. For a 2-year period, three trenches just inside the western perimeter of the landfill had received liquid discharges of both sewage and washwater, which contained solvents. Ground-water monitoring wells, installed a few months after liquid discharge had been discontinued, indicated very low levels (less than 10 ppb) of solvents exist in the ground water downgradient from the disposal trenches. 13 refs., 7 figs., 1 tab.

Evans, J.C.; Fruland, R.M.; Glover, D.W.; Veverka, C.

1989-12-01

97

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

PubMed

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

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

2013-11-15

98

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

99

Recovery and Utilization of Gas from Sanitary Landfills. Evaluation of the Research Program of the Danish Minsitry of Energy.  

National Technical Information Service (NTIS)

A summary and evaluation are presented of the research, supported by the Danish Ministry of Energy, on recovery and utilization of gas from sanitary landfills. Also examples of full scale plants at some landfills of different size are presented. The resea...

1985-01-01

100

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

EPA Science Inventory

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

101

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

PubMed

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

Amini, Hamid R; Reinhart, Debra R

2011-01-01

102

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

SciTech Connect

This report addresses low-level waste disposal operations at the Idaho Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Disposal Facility (ICDF) landfill from the start of operations in Fiscal Year 2003 through Fiscal Year 2008. The ICDF was authorized in the Operable Unit 3-13 Record of Decision for disposal of waste from the Idaho National Laboratory Site CERCLA environmental restoration activities. The ICDF has been operating since 2003 in compliance with the CERCLA requirements and the waste acceptance criteria developed in the CERCLA process. In developing the Operable Unit 3-13 Record of Decision, U.S. Department of Energy Order (DOE) 435.1, 'Radioactive Waste Management', was identified as a 'to be considered' requirement for the ICDF. The annual review requirement under DOE Order 435.1 was determined to be an administrative requirement and, therefore, annual reviews were not prepared on an annual basis. However, the landfill has been operating for 5 years and, since the waste forms and inventories disposed of have changed from what was originally envisioned for the ICDF landfill, the ICDF project team has decided that this annual review is necessary to document the changes and provide a basis for any updates in analyses that may be necessary to continue to meet the substantive requirements of DOE Order 435.1. For facilities regulated under DOE Order 435.1-1, U.S. DOE Manual 435.1-1, 'Radioactive Waste Management', IV.P.(4)(c) stipulates that annual summaries of low-level waste disposal operations shall be prepared with respect to the conclusions and recommendations of the performance assessment and composite analysis. Important factors considered in this review include facility operations, waste receipts, and results from monitoring and research and development programs. There have been no significant changes in operations at the landfill in respect to the disposal geometry, the verification of waste characteristics, and the tracking of inventories against total limits that would affect the results and conclusions of the performance assessment. Waste receipts to date and projected waste receipts through Fiscal Year 2012 are both greater than the inventory assessed in the performance assessment and composite analysis. The waste forms disposed of to the landfill are different from the waste form (compacted soil) assessed in the performance assessment. The leak detection system and groundwater monitoring results indicate the landfill has not leaked. The results of the performance assessment/composite analysis are valid (i.e., there is still a reasonable expectation of meeting performance objectives) but the new information indicates less conservatism in the results than previously believed.

Karen Koslow

2009-08-31

103

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

PubMed

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

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

2009-03-01

104

Attenuation of Methane and Nonmethane Organic Compounds in Landfill Gas Affected Soils  

Microsoft Academic Search

Landfill gas (LFG) contains high concentrations of methane, which contributes to the greenhouse effect. LFG also contains aromatic hydrocarbons and chlorinated aliphatics, which, by emission to ambient air, can be a local health threat. In addition, chlorinated aliphatics may also influence the earths ozone layer.The objectives of the study were to investigate the degradation of LFG constituents in LFG-affected soils,

Peter Kjeldsen; Anne Dalager; Kim Broholm

1997-01-01

105

Environmental and economic assessment of landfill gas electricity generation in Korea using LEAP model  

Microsoft Academic Search

As a measure to establish a climate-friendly energy system, Korean government has proposed to expand landfill gas (LFG) electricity generation capacity. The purpose of this paper is to analyze the impacts of LFG electricity generation on the energy market, the cost of generating electricity and greenhouse gases emissions in Korea using a computer-based software tool called Long-range Energy Alternative Planning

Ho-Chul Shin; Jin-Won Park; Ho-Seok Kim; Eui-Soon Shin

2005-01-01

106

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

107

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

108

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

PubMed

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

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

2013-10-01

109

Landfill gas collection system components: A review of system components and options, plus a few tips on saving costs  

SciTech Connect

A continuing debate in the solid waste industry is whether landfill gas-to-energy systems can be cost effective, even profitable, ventures. Energy tax credits have helped encourage development of more than 150 projects in the past decade, but these subsidies ended when Congress slashed plenty to trim the new federal budget. Now, all but the largest landfills are apt to come under greater cost scrutiny as gas control systems are explored or considered. Many elements are involved when estimating costs of landfill gas collection systems installed at municipal solid waste landfills. Construction costs vary widely from project to project due to specific site conditions, construction market, and prevailing wage rates. However, some associated costs are consistent, within a range, from project to project.

Michels, M.S. [CDM, Milwaukee, WI (United States)

1996-01-01

110

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

111

Monitoring of leachate quality stored in gas ventilation pipes for evaluating the degree of landfill stabilization.  

PubMed

Monitoring of leachate quality is the essential measure in aftercare for evaluating landfill stabilization. Generally, the most common way of leachate monitoring is executed at the inlet of the leachate treatment facility. However, it does not necessarily reflect the actual state of the site. Thus, methodologies which focus on both the discharge, in order to determine when the post-closure care of the facility should terminate, and on the degree of waste stabilization in the landfill are required. In the present study, monitoring of leachate quality stored in 68 gas ventilation pipes was conducted and the degree of waste stabilization at each location in the landfill was estimated by a statistical approach using the results obtained by monitoring. Leachate characteristics varied significantly for each pipe but seemed to reflect the waste condition of the nearby location. Correlation among the analysed items was quite high. Namely, the difference of leachate quality seemed to be categorized only by the level of concentration but not by the specific characteristics. To confirm this, Euclidean distances of dissimilarity were calculated by multidimensional scaling using six items of leachate quality and temperature. Two factors (thickness of leachate and concentration of total organic carbon (TOC) and electric conductivity (EC)) that distinguish leachate characteristics appeared. To indicate the degree of stabilization by location, the spatial distribution of TOC, total nitrogen (TN), inorganic carbon (IC), and chloride ion were estimated by using the ordinary Kriging methodology. As the result, it was estimated that the concentration of leachate existing within the landfill, especially TN, was higher than the completion criteria for leachate in most parts of the investigated area. PMID:20937618

Tojo, Yasumasa; Sato, Masahiro; Matsuo, Takayuki; Matsuto, Toshihiko

2011-01-01

112

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

Flix, Juliana S; Domeo, Celia; Nern, Cristina

2013-03-01

113

Field system for continuous measurement of landfill gas pressures and temperatures.  

SciTech Connect

The driving forces for gas movement in the subsurface include both concentration gradients (diffusion) and pressure gradients (convection). Near the top of the landfill, small soil gas pressure differences with respect to atmospheric pressure have been typically disregarded but may be important to considerations of gas flux into and out of landfill cover materials. The authors have developed a portable, inexpensive system using off-the-shelf components to sensitively monitor pressures, temperatures and meteorological variables on a continuous basis. Previous experience has indicated that continuous monitoring of pressure changes is necessary to understand the dynamics of convection in the shallow subsurface. This application relies on a distributed network of commercially available Z-180 microprocessor-based integrated controllers to condition signals from electronic pressure transducers, meteorological sensors, and various temperature-sensing devices : thermocouples, thermistors and resistance temperature detectors (RTDs). Output is recorded continuously over an AppletalkTM network. The sensitivity of the authors' current system exceeds 4 Pa for pressure and 0.01 C for temperature (thermistor sensors). This paper will describe the basic system components. The various choices for both temperature and pressure sensors will be discussed with respect to their sensitivity, adaptability and resolution. In addition, sample data output will be presented to illustrate the dynamics of shallow subsurface pressure and temperature changes.

Spokas, K. A.; Bogner, J. E.; Environmental Research

1996-01-01

114

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...

115

Proposal to reduce greenhouse gas emissions via landfill gas management in Greater Buenos Aires, Argentina. Final report  

SciTech Connect

The purpose of this project was to evaluate the feasibility of reducing the emission of greenhouse gases by collection, flaring, and possibly beneficially using the gas from landfills in Greater Buenos Aires, Argentina (GBA). Another purpose was to prepare a proposal to the US Initiative on Joint Implementation (USIJI) for a project to collect and possibly use the landfill gas (LFG). The project was carried out from September 30, 1997 through September 30, 1998. Collection and flaring of gas is feasible provided private firms have sufficient incentive to obtain greenhouse gas emission reduction benefits. The value of those benefits that would be required to motivate funding of an LFG management project was not explicitly determined. However, one independent power producer has expressed an interest in funding the first phase of the proposed project and paid for a detailed feasibility study which was conducted in August and September of 1998. As a result of this project, a proposal was submitted to the USIJI Evaluation Panel in June, 1998. In August, 1998, an office was established for reviewing and approving joint implementation proposals. The proposal is currently under review by that office.

Jones, D.B.

1998-10-01

116

Electrical power obtained from burning landfill gas into a gas turbine generator: Experience after one year of operation  

SciTech Connect

A typical example of a ``waste to energy'' concept can be found also in the landfill environment. The biogas derived by fermentation process is usually burnt into gas engines. This choice is usually due to the electric efficiency that is normally higher than gas turbine application and to the size that usually, almost in Italian landfill size, does not allow power higher than 1,000 kW. On the other side gas turbine applications, typically based on generator sets greater than 1,000 kW do not require special biogas pre-treatment; require less maintenance and have an extremely higher reliability. The paper describes an application of a gas turbine generator of 4,800 kW outlining the experiences collected after one year of operation. During this period, the system fulfilled the target of a total operating time greater than 8,000 hours. Description is done of the biogas compression system feeding the turbine and also of the subsystem adopted to reach the above mentioned target reliability.

Fabbri, R.; Mignani, N.

1998-07-01

117

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

118

Radiolytic Bubble Gas Hydrogen Compositions  

SciTech Connect

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

Hester, J.R.

2003-02-05

119

Radiolytic Bubble Gas Hydrogen Compositions  

SciTech Connect

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

Hester, J.R.

2001-08-28

120

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 1124, 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

121

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.

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

2012-04-01

122

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

123

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...

124

Evaluation test on a landfill gas-fired turbine at the Los Angeles County Sanitation District's Puente Hill Landfill Electric Generation Station. Air pollution test report  

SciTech Connect

A cooperative test program was conducted from February 25 through February 27, 1986 by Air Resources Board (ARB) and South Coast Air Quality Management District (SCAQMD) staff to evaluate the gaseous constituents from untreated landfill gas used to fuel a turbine and the emissions from that turbine located at the Los Angeles County Sanitation District's Puente Hills Electric Generating Station. The turbine was fueled with gases generated by the anaerobic decomposition of buried refuse at the Los Angeles County Sanitation District's Puente Hills Landfill. Emissions of criteria pollutant as determined from ARB test data are reported. Mass flow rates and destruction and removal efficiencies (DRE) of non-criteria pollutant compounds determined at the stack from SCQAMD bag-sample test data and mass-flow rates and DRE's for chlorinated and aromatic compounds determined from data from ARB resin samples are presented. Destruction and removal efficiencies based on mass-flow rates for chlorinated compounds ranged from 17 to 99+ percent and for aromatic compounds ranged from negative to 99+ percent. The possible formation of the compounds - chlorinated dioxins, furans, and polychlorinated biphenyls - was considered and samples were taken for analyses for these compounds. Dioxins, furans, and polychlorinated biphenyls were not detected in the inlet nor the outlet gas stream samples.

Not Available

1986-07-01

125

Movement of unlined landfill under preloading surcharge  

Microsoft Academic Search

As organic solid waste is decomposed in a landfill and mass is lost due to gas and leachate formation, the landfill settles. Settlement of a landfill interferes with the rehabilitation and subsequent use of the landfill site after closure. This study examined the soil\\/solid waste movement at the Al-Qurain landfill in Kuwait after 15 years of closure as plans are

Anwar F. Al-Yaqout; Mohamed F. Hamoda

2007-01-01

126

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

127

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

128

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

129

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.

130

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

SciTech Connect

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

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

2000-10-20

131

Performance and bacterial compositions of aged refuse reactors treating mature landfill leachate  

Microsoft Academic Search

Aged landfill leachates become more refractory over time and difficulty to treat. Recently, aged refuse bioreactors show great promise in treating leachates. In this study, aged refuse bioreactors were constructed to simulate landfill leachate degradation process. The characteristics of leachate were: CODcr, ?2200mg\\/L; BOD5, ?280mg\\/L; total nitrogen, ?2030mg\\/L; and ammonia, ?1900mg\\/L. Results showed that bioreactor could remove leachate pollutants effectively

Bing Xie; Shunzi Xiong; Shaobo Liang; Chong Hu; Xiaojun Zhang; Jun Lu

132

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

SciTech Connect

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

Emerson, C.W.

1999-11-01

133

Energy potential of modern landfills  

SciTech Connect

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

Bogner, J.E.

1990-01-01

134

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

NASA Astrophysics Data System (ADS)

Vertically aligned carbon nanotube (CNT) layers were synthesized on Fe-coated low-cost alumina substrates using radio-frequency plasma enhanced chemical vapour deposition (RF-PECVD) technology. A miniaturized CNT-based gas sensor array was developed for monitoring landfill gas (LFG) at a temperature of 150 C. The sensor array was composed of 4 sensing elements with unmodified CNT, and CNT loaded with 5 nm nominally thick sputtered nanoclusters of platinum (Pt), ruthenium (Ru) and silver (Ag). Chemical analysis of multicomponent gas mixtures constituted of CO2, CH4, H2, NH3, CO and NO2 has been performed by the array sensor responses and pattern recognition based on principal component analysis (PCA). The PCA results demonstrate that the metal-decorated and vertically aligned CNT sensor array is able to discriminate the NO2 presence in the multicomponent mixture LFG. The NO2 gas detection in the mixture LFG was proved to be very sensitive, e.g.: the CNT:Ru sensor shows a relative change in the resistance of 1.50% and 0.55% for NO2 concentrations of 3.3 ppm and 330 ppb dispersed in the LFG, respectively, with a wide NO2 gas concentration range measured from 0.33 to 3.3 ppm, at the sensor temperature of 150 C. The morphology and structure of the CNT networks have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. A forest-like nanostructure of vertically aligned CNT bundles in the multi-walled form appeared with a height of about 10 m and a single-tube diameter varying in the range of 5-35 nm. The intensity ratio of the Raman spectroscopy D-peak and G-peak indicates the presence of disorder and defects in the CNT networks. The size of the metal (Pt, Ru, Ag) nanoclusters decorating the CNT top surface varies in the range of 5-50 nm. Functional characterization based on electrical charge transfer sensing mechanisms in the metal-modified CNT-chemoresistor array demonstrates high sensitivity by providing minimal sub-ppm level detection, e.g., download up to 100 ppb NO2, at the sensor temperature of 150 C. The gas sensitivity of the CNT sensor array depends on operating temperature, showing a lower optimal temperature of maximum sensitivity for the metal-decorated CNT sensors compared to unmodified CNT sensors. Results indicate that the recovery mechanisms in the CNT chemiresistors can be altered by a rapid heating pulse from room temperature to about 110 C. A comparison of the NO2 gas sensitivity for the chemiresistors based on disorderly networked CNTs and vertically aligned CNTs is also reported. Cross-sensitivity towards relative humidity of the CNT sensors array is investigated. Finally, the sensing properties of the metal-decorated and vertically aligned CNT sensor arrays are promising to monitor gas events in the LFG for practical applications with low power consumption and moderate sensor temperature.

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

2010-03-01

135

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

136

Influence of Tropical Seasonal Variations Operation Modes and Waste Composition on Leachate Characteristics and Landfill Settlement  

Microsoft Academic Search

This paper presents the ongoing research finding during the past 2 years, under the tropical monsoon influence on leachate characterization and quantity; and settlement variation under ambient conditions at AIT campus. Five Pilot-Scale landfill lysimeters contain substrate with different type of waste, operational arrangement and top cover designs were investigated. The leachate characteristic, generation, settlement variation and climatic parameters had

P. Kuruparan; O. Tubtimthai; C. Visvanathan; J. Trnkler

137

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

PubMed

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

Woon, K S; Lo, Irene M C

2013-08-01

138

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

139

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

EPA Science Inventory

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

140

Pilot scale evaluation of the BABIU process--upgrading of landfill gas or biogas with the use of MSWI bottom ash.  

PubMed

Biogas or landfill gas can be converted to a high-grade gas rich in methane with the use of municipal solid waste incineration bottom ash as a reactant for fixation of CO2 and H2S. In order to verify results previously obtained at a laboratory scale with 65-90 kg of bottom ash (BA), several test runs were performed at a pilot scale, using 500-1000 kg of bottom ash and up to 9.2 Nm(3)/h real landfill gas from a landfill in the Tuscany region (Italy). The input flow rate was altered. The best process performance was observed at a input flow rate of 3.7 Nm(3)/(htBA). At this flow rate, the removal efficiencies for H2S were approximately 99.5-99%. PMID:24120459

Mostbauer, P; Lombardi, L; Olivieri, T; Lenz, S

2014-01-01

141

Renewable Energy 32 (2007) 12431257 Methane generation in landfills  

E-print Network

. Some of the modern regulated landfills attempt to capture and utilize landfill biogas, a renewable collecting landfill biogas worldwide. The landfills that capture biogas in the US collect about 2.6 million. All rights reserved. Keywords: Landfill gas; Renewable energy; Municipal solid waste; Biogas; Methane

Columbia University

142

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

Microsoft Academic Search

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

Thian Yew Gan; Gerry Friesen

1991-01-01

143

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

PubMed

The present paper focuses on a largely unexplored field of landfill-site valorization in combination with the construction and operation of a centralized olive mill wastewater (OMW) treatment facility. The latter consists of a wastewater storage lagoon, a compact anaerobic digester operated all year round and a landfill-based final disposal system. Key elements for process design, such as wastewater pre-treatment, application method and rate, and the potential effects on leachate quantity and quality, are discussed based on a comprehensive literature review. Furthermore, a case-study for eight (8) olive mill enterprises generating 8700m(3) of wastewater per year, was conceptually designed in order to calculate the capital and operational costs of the facility (transportation, storage, treatment, final disposal). The proposed facility was found to be economically self-sufficient, as long as the transportation costs of the OMW were maintained at ?4.0/m(3). Despite that EU Landfill Directive prohibits wastewater disposal to landfills, controlled application, based on appropriately designed pre-treatment system and specific loading rates, may provide improved landfill stabilization and a sustainable (environmentally and economically) solution for effluents generated by numerous small- and medium-size olive mill enterprises dispersed in the Mediterranean region. PMID:23792820

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

2013-10-15

144

Economic Feasibility of Converting Landfill Gas to Natural Gas for Use as a Transportation Fuel in Refuse Trucks  

E-print Network

to global climate change, diesel-fueled refuse trucks are one of the most concentrated sources of health-threatening air pollution in most cities. The landfills that they ultimately place their waste in are the second largest source of human-related methane...

Sprague, Stephen M.

2011-02-22

145

Methane Balance of a Bioreactor Landfill in Latin America  

Microsoft Academic Search

This paper presents results from a methane (CH4) gas emission characterization survey conducted at the Loma Los Colorados landfill located 60 km from Santiago, Chile. The landfill receives approximately 1 million metric tons (t) of waste annually, and is equipped with leachate control systems and landfill gas collection systems. The collected leachate is recirculated to enable operation of the landfill

Jenny Sanderson; Patrick Hettiaratchi; Carlos Hunte; Omar Hurtado; Alejandro Keller; Chart Chiemchaisri; Wilai Chiemchaisri; Sayan Tudsri; Sunil Kumar; Josias Zietsman; Muhammad Bari; Aaron Rand; Bhushan Gokhale; Dominique Lord; Chettiyappan Visvanathan; Melissa Weitz; Jeffrey Coburn; Edgar Salinas; Ahmed Soliman; Robert Jacko; Nancy Burton; Atin Adhikari; Yulia Iossifova; Sergey Grinshpun; Tiina Reponen; James Wilson; Maureen Mullen; Andrew Bollman; Kirstin Thesing; Manish Salhotra; Frank Divita; James Neumann; Jason Price; James DeMocker; Mae Gustin; Jody Ericksen; George Fernandez; Ryan LeBouf; Liesel Yesse; Alan Rossner; Deborah Luecken; Alan Cimorelli; Wei-Hsin Chen; Shan-Wen Du; Hsi-Hsien Yang; Jheng-Syun Wu; Diane Ivy; James Mulholland; Armistead Russell

2008-01-01

146

ENGINEERING BULLETIN: LANDFILL COVERS  

EPA Science Inventory

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

147

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

148

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

149

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

150

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

PubMed

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

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

2011-01-01

151

40 CFR 60.752 - Standards for air emissions from municipal solid waste landfills.  

Code of Federal Regulations, 2012 CFR

...this section. (B) If the landfill is permanently closed, a closure...site-specific factors involved with landfill gas system design, alternative...horizontal trenches only, leachate collection components, and...the gas generated within the landfill as required by...

2012-07-01

152

40 CFR 60.752 - Standards for air emissions from municipal solid waste landfills.  

Code of Federal Regulations, 2011 CFR

...this section. (B) If the landfill is permanently closed, a closure...site-specific factors involved with landfill gas system design, alternative...horizontal trenches only, leachate collection components, and...the gas generated within the landfill as required by...

2011-07-01

153

40 CFR 60.752 - Standards for air emissions from municipal solid waste landfills.  

Code of Federal Regulations, 2013 CFR

...this section. (B) If the landfill is permanently closed, a closure...site-specific factors involved with landfill gas system design, alternative...horizontal trenches only, leachate collection components, and...the gas generated within the landfill as required by...

2013-07-01

154

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

155

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...

156

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 ...

157

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

PubMed

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

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

2011-01-01

158

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

159

Mill Seat Landfill Bioreactor Renewable Green Power (NY)  

SciTech Connect

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

Barton & Loguidice, P.C.

2010-01-07

160

78 FR 14773 - U.S. Environmental Solutions Toolkit-Landfill Standards  

Federal Register 2010, 2011, 2012, 2013

...goods or services relevant to landfill environmental standards. The...contact information, and landfill environmental standards category...following list: (a) Liners (b) Leachate Collection Systems (c) Landfill Gas Collection (d)...

2013-03-07

161

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

PubMed

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

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

2014-10-01

162

Investigations into the landfill behaviour of pretreated wastes.  

PubMed

Mechanical-biological treatment of municipal solid waste has become popular throughout the UK and other parts of Europe to enable compliance with the Landfill Directive. Pretreatment will have a major influence on the degradation and settlement characteristics of the waste in landfills owing to the changes in the composition and properties of the wastes. This paper presents and compares the results of long term landfill behaviour of the UK and German MBT wastes pretreated to different standards. The gas generating potential, leachate quality and settlement characteristics are highlighted. The results reveal that it is possible to achieve stabilisation of MBT waste within a year and the biogas yield and leachate strength of German MBT waste was significantly reduced compared with the UK MBT waste. The settlement resulting from mechanical creep is more significant than the biodegradation induced settlement in both cases. PMID:22513159

Siddiqui, A A; Richards, D J; Powrie, W

2012-07-01

163

Metal Oxides Remove Hydrogen Sulfide from Landfill Gas Produced from Waste Mixed with Plaster Board under Wet Conditions  

Microsoft Academic Search

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

Ove Bergersen; Ketil Haarstad; Van Bowersox; Christopher Lehmann; David Grantz; Kathleen Brown; Walid Bouhamra; Denise Lamoureux; John Evans; Petros Koutrakis; James Winebrake; James Corbett; Aaron Falzarano; J. Hawker; Karl Korfmacher; Sai Ketha; Steve Zilora; Serap Erdal; Laurel Berman; Daniel Hryhorczuk; Saeed Abolhasani; H. Frey; Kangwook Kim; William Rasdorf; Phil Lewis; Shih-Hao Pang; Allan Chambers; Melvin Strosher; Tony Wootton; Jan Moncrieff; Philip McCready; Litao Wang; Jiming Hao; Kebin He; Shuxiao Wang; Junhua Li; Qiang Zhang; David Streets; Joshua Fu; Carey Jang; Hideto Takekawa; Satoru Chatani; Stephanie Konopa; James Mulholland; Matthew Realff; Paul Lemieux; Jaehyun Lim; Liya Yu; Yu. Kostetski; Cheolsoo Lim; Jungho Ryu; Jongchoon Kim; Christian Hogrefe; Kevin Civerolo; Winston Hao; Jia-Yeong Ku; Eric Zalewsky; Gopal Sistla; Ram Hashmonay

2008-01-01

164

LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL  

SciTech Connect

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

Don Augenstein

1999-01-11

165

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

PubMed

Waste management can be regarded as a cross-cutting environmental 'mega-issue'. Sound waste management practices support the provision of basic needs for general health, such as clean air, clean water and safe supply of food. In addition, climate change mitigation efforts can be achieved through reduction of greenhouse gas emissions from waste management operations, such as landfills. Landfills generate landfill gas, especially methane, as a result of anaerobic degradation of the degradable components of municipal solid waste. Evaluating the mode of generation and collection of landfill gas has posted a challenge over time. Scientifically, landfill gas generation rates are presently estimated using numerical models. In this study the Intergovernmental Panel on Climate Change's Waste Model is used to estimate the methane generated from a Malaysian sanitary landfill. Key parameters of the model, which are the decay rate and degradable organic carbon, are analysed in two different approaches; the bulk waste approach and waste composition approach. The model is later validated using error function analysis and optimum decay rate, and degradable organic carbon for both approaches were also obtained. The best fitting values for the bulk waste approach are a decay rate of 0.08 y(-1) and degradable organic carbon value of 0.12; and for the waste composition approach the decay rate was found to be 0.09 y(-1) and degradable organic carbon value of 0.08. From this validation exercise, the estimated error was reduced by 81% and 69% for the bulk waste and waste composition approach, respectively. In conclusion, this type of modelling could constitute a sensible starting point for landfills to introduce careful planning for efficient gas recovery in individual landfills. PMID:25323145

Govindan, Siva Shangari; Agamuthu, P

2014-10-01

166

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

167

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

168

Estimation of landfill emission lifespan using process oriented modeling  

SciTech Connect

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

Ustohalova, Veronika [Institute of Waste Management, University of Duisburg-Essen, Universitaetsstrasse 15, 45141 Essen (Germany)]. E-mail: veronika.ustohalova@uni-essen.de; Ricken, Tim [Institute of Mechanics, University of Duisburg-Essen, Universitaetsstrasse 15, 45141 Essen (Germany); Widmann, Renatus [Institute of Waste Management, University of Duisburg-Essen, Universitaetsstrasse 15, 45141 Essen (Germany)

2006-07-01

169

Case study of landfill reclamation at a Florida landfill site.  

PubMed

A landfill reclamation project was considered to recover landfill airspace and soil, reduce future groundwater impacts by removing the waste buried in the unlined area, and optimize airspace use at the site. A phased approach was utilized to evaluate the technical and economic feasibility of the reclamation project; based on the results of these evaluations, approximately 6.8 ha of the unlined cells were reclaimed. Approximately 371,000 in-place cubic meters of waste was mined from 6.8 ha in this project. Approximately 230,600 cubic meters of net airspace was recovered due to beneficial use of the recovered final cover soil and reclaimed soil as intermediate and daily cover soil, respectively, for the current landfill operations. This paper presents the researchers' landfill reclamation project experience, including a summary of activities pertaining to reclamation operations, an estimation of reclamation rates achieved during the project, project costs and benefits, and estimated composition of the reclaimed materials. PMID:23089299

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

2013-01-01

170

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

171

Methane generation from UK landfill sites and its use as an energy resource  

Microsoft Academic Search

Emissions of methane from UK landfill sites are estimated to be about 46% of the country's total releases of methane to atmosphere. Combusting landfill gas offers an effective way of reducing emissions from this source. Using landfill gas as an energy resource also reduces dependence on fossil fuel sources of energy. There are currently over 60 landfill sites in the

Elisabeth Aitchison

1996-01-01

172

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

173

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

Lpez, Ana; Lobo, Amaya

2014-08-01

174

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

PubMed

The non-methane organic compound (NMOC) emission rate is used to assess compliance with landfill gas emission regulations by the United States Environmental Protection Agency (USEPA). A recent USEPA Report (EPA/600/R-11/033) employed a ratio method to estimate speciated NMOC emissions (i.e., individual NMOC emissions): speciated NMOC emissions=measured methane (CH4) emission multiplied by the ratio of individual NMOCs concentration relative to CH4 concentration (CNMOCs/ [Formula: see text] ) in the landfill header gas. The objectives of this study were to (1) evaluate the efficacy of the ratio method in estimating speciated NMOC flux from landfills; (2) determine for what types of landfills the ratio method may be in error and why, using recent field data to quantify the spatial variation of (CNMOCs/ [Formula: see text] ) in landfills; and (3) formulate alternative models for estimating NMOC emissions from landfills for cases in which the ratio method results in biased estimates. This study focuses on emissions through landfill covers measured with flux chambers and evaluates the utility of the ratio method for estimating NMOC emission through this pathway. Evaluation of the ratio method was performed using CH4 and speciated NMOC concentration and flux data from 2012/2013 field sampling of four landfills, an unpublished landfill study, and literature data from three landfills. The ratio method worked well for landfills with thin covers (<40cm), predicting composite NMOC flux (as hexane-C) to within a factor of 10 for 13 out of 15 measurements. However, for thick covers (?40cm) the ratio method overestimated NMOC emissions by ?10 for 8 out of 10 measurements. Alternative models were explored incorporating other chemical properties into the ratio method. A molecular weight squared (MW)(2)-modified ratio equation was shown to best address the tendency of the current ratio method to overestimate NMOC fluxes for thick covers. While these analyses were only performed using NMOC fluxes through landfill covers measured with flux chambers, results indicate the current USEPA approach for estimating NMOC emissions may overestimate speciated NMOC emission ?10 for many compounds. PMID:25108756

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

2014-11-01

175

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

NASA Astrophysics Data System (ADS)

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

Sung, K.; Park, S.

2007-12-01

176

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

177

Analysis of the welfare impacts of landfilling coal FGD by-product  

SciTech Connect

The recycling of Flue Gas Desulfurization (FGD) by-products results in two types of benefits: accounting benefits in the form of avoided landfilling costs which accrue to the entity generating the waste; and social benefits, which accrue to the individuals affected by the landfill`s presence. This paper develops a methodology to quantify social costs from four landfills in Franklin County, Ohio.

Hite, D.; Chern, W.S.; Hitzhusen, F.J. [Ohio State Univ., Columbus, OH (United States). Dept. of Agricultural Economics

1994-12-31

178

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

EPA Science Inventory

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

179

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

180

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 liquidliquid 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

181

Corrosion inhibition by control of gas composition during mist drilling  

SciTech Connect

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

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

1981-05-01

182

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

183

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

184

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

SciTech Connect

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

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

1998-02-25

185

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

186

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

187

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

188

An assessment of bioreactor landfill costs and benefits.  

PubMed

Because effective operation of bioreactor landfills involves careful operation and construction of infrastructure beyond that necessary in traditional landfills, upfront capital and operating costs are greater than those associated with traditional landfills. Prior to investing in bioreactor landfills, landfill owners must be convinced that larger short-term expenses (e.g., liquid and/or air injection infrastructure) will be balanced by future economic benefits (e.g., extension of landfill life, reduced leachate treatment costs, etc.). The purpose of this paper is to describe an economic model developed to evaluate the impact of various operational (anaerobic, aerobic, or hybrid) and construction (retrofit and as-built) bioreactor landfill strategies on project economics. Model results indicate retrofit bioreactor landfills are more expensive than traditional landfills, while both the as-built and aerobic bioreactor landfills are less costly. Simulation results indicate the parameters that influence bioreactor economics most significantly are airspace recovery, gas recovery and subsequent use to generate electricity, and savings resulting from reduced leachate treatment costs. PMID:19167875

Berge, Nicole D; Reinhart, Debra R; Batarseh, Eyad S

2009-05-01

189

Characteristics and treatment of leachates from domestic landfills  

Microsoft Academic Search

The main objectives of this study were to develop a useful database for the leachate quality of Hong Kong landfills, and to compare different experimental trials for the treatment of methanogenic-stage sanitary landfill leachate, which is generally characterized by a low chemical oxygen demand (COD) of 3000 mg L?1 or less. Extensive chemical analysis data of leachate composition generated from

Irene M.-C. Lo

1996-01-01

190

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

PubMed

The objectives of this study were to compare the types and levels of volatile methyl siloxanes (VMS) present in biogas generated in the anaerobic digesters and landfills, evaluate the energetics of siloxane transformations under anaerobic conditions, compare the conditions in anaerobic digesters and municipal solid waste (MSW) landfills which result in differences in siloxane compositions. Biogas samples were collected at the South District Wastewater Treatment Plant and South Dade Landfill in Miami, Florida. In the digester gas, D4 and D5 comprised the bulk of total siloxanes (62% and 27%, respectively) whereas in the landfill gas, the bulk of siloxanes were trimethylsilanol (TMSOH) (58%) followed by D4 (17%). Presence of high levels of TMSOH in the landfill gas indicates that methane utilization may be a possible reaction mechanism for TMSOH formation. The free energy change for transformation of D5 and D4 to TMSOH either by hydrogen or methane utilization are thermodynamically favorable. Either hydrogen or methane should be present at relatively high concentrations for TMSOH formation which explains the high levels present in the landfill gas. The high bond energy and bond distance of the Si-O bond, in view of the atomic sizes of Si and O atoms, indicate that Si atoms can provide a barrier, making it difficult to break the Si-O bonds especially for molecules with specific geometric configurations such as D4 and D5 where oxygen atoms are positioned inside the frame formed by the large Si atoms which are surrounded by the methyl groups. PMID:25160660

Tansel, Berrin; Surita, Sharon C

2014-11-01

191

ESTIMATE OF GLOBAL METHANE EMISSIONS FROM LANDFILLS AND OPEN DUMPS  

EPA Science Inventory

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

192

Geothermal gas compositions in yellowstone National Park, USA  

USGS Publications Warehouse

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

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

1992-01-01

193

FULL SCALE BIOREACTOR LANDFILL FOR CARBON SEQUESTRATION AND GREENHOUSE EMISSION CONTROL  

Microsoft Academic Search

The Yolo County Department of Planning and Public Works is constructing a full-scale bioreactor landfill as a part of the Environmental Protection Agency's (EPA) Project XL program to develop innovative approaches for carbon sequestration and greenhouse emission control. The overall objective is to manage landfill solid waste for rapid waste decomposition and maximum landfill gas generation and capture for carbon

Ramin Yazdani; Jeff Kieffer; Heather Akau

2002-01-01

194

FULL SCALE BIOREACTOR LANDFILL FOR CARBON SEQUESTRATION AND GREENHOUSE EMISSION CONTROL  

Microsoft Academic Search

The Yolo County Department of Planning and Public Works is constructing a full-scale bioreactor landfill as a part of the Environmental Protection Agency's (EPA) Project XL program to develop innovative approaches while providing superior environmental protection. The overall objective is to manage landfill solid waste for rapid waste decomposition, maximum landfill gas generation and capture, and minimum long-term environmental consequences.

Ramin Yazdani; Jeff Kieffer; Heather Akau

2002-01-01

195

FULL SCALE BIOREACTOR LANDFILL FOR CARBON SEQUESTRATION AND GREENHOUSE EMISSION CONTROL  

Microsoft Academic Search

The Yolo County Department of Planning and Public Works is constructing a full-scale bioreactor landfill as a part of the Environmental Protection Agency's (EPA) Project XL program to develop innovative approaches for carbon sequestration and greenhouse emission control. The overall objective is to manage landfill solid waste for rapid waste decomposition and maximum landfill gas generation and capture for carbon

Ramin Yazdani; Jeff Kieffer; Heather Akau

2003-01-01

196

Full Scale Bioreactor Landfill for Carbon Sequestration and Greenhouse Emission Control  

Microsoft Academic Search

The Yolo County Department of Planning and Public Works constructed a full-scale bioreactor landfill as a part of the Environmental Protection Agency's (EPA) Project XL program to develop innovative approaches for carbon sequestration and greenhouse emission control. The overall objective was to manage landfill solid waste for rapid waste decomposition and maximum landfill gas generation and capture for carbon sequestration

Ramin Yazdani; Jeff Kieffer; Kathy Sananikone; Don Augenstein

2005-01-01

197

Airborne Emissions of Mercury from Municipal Solid Waste. II: Potential Losses of Airborne Mercury before Landfill  

Microsoft Academic Search

Waste distribution and compaction at the working face of municipal waste landfills releases mercury vapor (Hg) to the atmosphere, as does the flaring of landfill gas. Waste storage and processing before its addition to the landfill also has the potential to release Hg to the air if it is initially present or formed by chemical reduction of Hg to Hg

George R. Southworth; Steve E. Lindberg; Mary Anna Bogle; Hong Zhang; Todd Kuiken; Jack Price; Debra Reinhart; Hala Sfeir

2005-01-01

198

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

NASA Astrophysics Data System (ADS)

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

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

2010-02-01

199

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.

200

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

SciTech Connect

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

Bogner, J.; Spokas, K. [Argonne National Lab., IL (United States); Niemann, M.; Niemann, L. [Rust Environment and Infrastructure, Oak Brook, IL (United States); Baker, J. [WMX Technology Center, Geneva, IL (United States)

1997-08-01

201

Performance-based design of landfill liners  

Microsoft Academic Search

Factors affecting chemical transport in geomembrane, clay and composite liners are reviewed, and a simplified performance-based method for evaluating landfill bottom liners is presented. For single geomembrane liners, mass transport of inorganic chemicals is calculated from the leakage rate from holes for an assumed frequency of hole occurrence. Transport of organic chemicals is obtained by accounting for molecular diffusion through

T Katsumi; C. H Benson; G. J Foose; M Kamon

2001-01-01

202

Field testing the Raman gas composition sensor for gas turbine operation  

SciTech Connect

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

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

2012-01-01

203

Effects of gas composition on the performance and emissions of compressed natural gas engines  

Microsoft Academic Search

Natural gas is considered to be a promising alternative fuel for passenger cars, truck transportation and stationary engines\\u000a providing positive effects both on the environment and energy security. However, since the composition of natural gas fuel\\u000a varies with location, climate and other factors, it is anticipated that such changes in fuel properties will affect emission\\u000a characteristics and performance of CNG

Byung Hyouk Min; Jin Taek Chung; Ho Young Kim

2002-01-01

204

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

205

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

SciTech Connect

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

PACKER, M.J.

2000-05-10

206

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

SciTech Connect

The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm{sup -3}, reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100 g CH{sub 4} m{sup -2} d{sup -1}, covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH{sub 4} m{sup -2} d{sup -1} and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity 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.

Rachor, Ingke, E-mail: i.rachor@ifb.uni-hamburg.de [University of Hamburg, Institute of Soil Science, Allende-Platz 2, 20146 Hamburg (Germany); Gebert, Julia; Groengroeft, Alexander; Pfeiffer, Eva-Maria [University of Hamburg, Institute of Soil Science, Allende-Platz 2, 20146 Hamburg (Germany)

2011-05-15

207

Estimation of waste component-specific landfill decay rates using laboratory-scale decomposition data.  

PubMed

The current methane generation model used by the U.S. EPA (Landfill Gas Emissions Model) treats municipal solid waste (MSW) as a homogeneous waste with one decay rate. However, component-specific decay rates are required to evaluate the effects of changes in waste composition on methane generation. Laboratory-scale rate constants, k(lab), for the major biodegradable MSW components were used to derive field-scale decay rates (k(field)) for each waste component using the assumption that the average of the field-scale decay rates for each waste component, weighted by its composition, is equal to the bulk MSW decay rate. For an assumed bulk MSW decay rate of 0.04 yr(-1), k(field) was estimated to be 0.298, 0.171, 0.015, 0.144, 0.033, 0.02, 0.122, and 0.029 yr(-1), for grass, leaves, branches, food waste, newsprint, corrugated containers, coated paper, and office paper, respectively. The effect of landfill waste diversion programs on methane production was explored to illustrate the use of component-specific decay rates. One hundred percent diversion of yard waste and food waste reduced the year 20 methane production rate by 45%. When a landfill gas collection schedule was introduced, collectable methane was most influenced by food waste diversion at years 10 and 20 and paper diversion at year 40. PMID:20496890

De la Cruz, Florentino B; Barlaz, Morton A

2010-06-15

208

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

1988-01-01

209

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

210

Landfill in a Bottle  

NSDL National Science Digital Library

In this activity, learners discover how landfills affect the natural environment. By observing a 2-liter bottle filled with household garbage over a month, learners can estimate how long it takes for average household garbage takes to break down.

Aquariums, Association O.

2009-01-01

211

Risk assessment of an old landfill regarding the potential of gaseous emissions--a case study based on bioindication, FT-IR spectroscopy and thermal analysis.  

PubMed

Risk assessment of two sections (I and II) of an old landfill (ALH) in Styria (Austria) in terms of reactivity of waste organic matter and the related potential of gaseous emissions was performed using conventional parameters and innovative tools to verify their effectiveness in practice. The ecological survey of the established vegetation at the landfill surface (plant sociological relevs) indicated no relevant emissions over a longer period of time. Statistical evaluation of conventional parameters reveals that dissolved organic carbon (DOC), respiration activity (RA(4)), loss of ignition (LOI) and total inorganic carbon (TIC) mostly influence the variability of the gas generation sum (GS(21)). According to Fourier Transform Infrared (FT-IR) spectral data and the results of the classification model the reactivity potential of the investigated sections is very low which is in accordance with the results of plant sociological relevs and biological tests. The interpretation of specific regions in the FT-IR spectra was changed and adapted to material characteristics. Contrary to mechanically-biologically treated (MBT) materials, where strong aliphatic methylene bands indicate reactivity, they are rather assigned to the C-H vibrations of plastics in old landfill materials. This assumption was confirmed by thermal analysis and the characteristic heat flow profile of plastics containing landfill samples. Therefore organic carbon contents are relatively high compared to other stable landfills as shown by a prediction model for TOC contents based on heat flow profiles and partial least squares regression (PLS-R). The stability of the landfill samples, expressed by the relation of CO(2) release and enthalpies, was compared to unreactive landfills, archeological samples, earthlike materials and hardly degradable organic matter. Due to the material composition and the aging process the landfill samples are located between hardly degradable, but easily combustible materials and thermally resistant materials with acquired stability. PMID:22902203

Tintner, Johannes; Smidt, Ena; Bhm, Katharina; Matiasch, Lydia

2012-12-01

212

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 landfills 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

213

Nitrogen and sulfate attenuation in simulated landfill bioreactors.  

PubMed

The characteristics of leachate from landfills vary according to site-specific conditions. Leachates from old landfills are often rich in ammonia nitrogen, posing potential adverse environmental impacts in the case of uncontrolled discharge. At landfills where leachate recirculation is practiced, leachate ammonia concentrations may accumulate to higher levels than during the single pass leaching. Using leachate recirculation with system modifications, separate aerobic and anoxic zones for nitrification and both autotrophic and heterotrophic denitrification can be provided. Results from simulated landfill bioreactors indicated that both nitrogenous and sulfur compounds can be attenuated through autotrophic denitrification, and leachate nitrate concentrations of 750 mg/L reduced to less than 1 mg/L by denitrification to nitrogen gas promoting this very common process in a landfill environment results in the reduction of both leachate ammonia and sulfate concentrations. PMID:11548007

Onay, T T; Pohland, F G

2001-01-01

214

Full-scale leachate-recirculating MSW landfill bioreactor assessments  

SciTech Connect

The integrated waste management hierarchy philosophy continues to develop as a useful tool to solve solid waste issues in an environmentally responsible manner. Recent statistics indicate that approximately two thirds of municipal solid waste in the United States is disposed in landfills. Current landfill operational technique involves the preparation of a waste containment facility, the filling of the waste unit, installation of the final cover, and the maintenance of the unit. This method of operation has proven to be reasonably effective in waste disposal, effectively minimizing risk by collecting the liquid that percolates through the waste, called leachates, at the bottom of the landfill, and controlling landfill gas with collection systems. Concerns over the longevity of containment systems components present questions that cannot be answered without substantial performance data. Landfills, as currently operated, serve to entomb dry waste. Therefore, the facility must be maintained in perpetuity, consuming funds and ultimately driving up waste collection costs. This presentation will describe a new form of solid waste landfill operation, it is a technique that involves controlled natural processes to break down landfilled waste, and further minimize risk to human health and the environment. A landfill operated in an active manner will encourage and control natural decomposition of landfilled waste. This can be accomplished by collecting leachate, and reinjecting it into the landfilled waste mass. Keeping the waste mass moist will lead to a largely anaerobic system with the capacity to rapidly stabilize the landfilled waste mass via physical, chemical and biological methods. The system has proven the ability to breakdown portions of the waste mass, and to degrade toxic materials at the laboratory scale.

Carson, D.A. [Environmental Protection Agency, Cincinnati, OH (United States)

1995-10-01

215

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; Jrgensen, Jrgen Henrik Bjerre; Ucendo, Inmaculada Maria Buendia; Mnster, Jacob G; Samuelsson, Jerker; Kjeldsen, Peter

2014-07-01

216

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

1989-01-01

217

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)

1994-12-20

218

RETROSPECTIVE EVALUATION OF THE EFFECTS OF SELECTED INDUSTRIAL WASTES ON MUNICIPAL SOLID WASTE STABILIZATION IN SIMULATED LANDFILLS  

EPA Science Inventory

The report is a retrospective evaluation of ten years of leachate and gas data collected from 19 simulated landfills (landfill cells) containing municipal solid waste codisposed with sewage sludge or industrial wastes. Physical and chemical parameters from each landfill cell are ...

219

1st International Conference on Final Sinks, September 23-25, 2010 Vienna, Austria From Sanitary to Sustainable Landfilling  

E-print Network

of Post-Closure Management for Landfills Kai Münnich (DE) Long Term Monitoring of Leachate Flux in Engineered Landfill Leachates Yasumasa Tojo (JP) Monitoring of Leachate Quality Stored in Gas Ventilation to Sustainable Landfilling: why, how, and when? #12;23rd September 2010 08:45 - 09:30 Registration 09:30 - 09

Szmolyan, Peter

220

Modeling of Multilayer Composite Fabrics for Gas Turbine Engine Containment Systems  

E-print Network

of the turbines. Contained gas turbine engines turn out to be safer in case of fan blade-out events by protectingModeling of Multilayer Composite Fabrics for Gas Turbine Engine Containment Systems J. Sharda1 ; C of multilayer composite fabrics used in a gas turbine engine containment system is developed. Specifically

Mobasher, Barzin

221

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

222

Municipal Solid WasteMunicipal Solid Waste Landfills In CitiesLandfills In Cities  

E-print Network

the above layer. Leachate collection & treatment system Storm water run-off gutters #12;Cross water and maintaining ground water quality d) Maintaining and operating the landfill gas collection sys & H) Rules 2000 #12;Environmental Laws in India · Water Act ­ 1976 · Air Act ­ 1981 · Environmental

Columbia University

223

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)...

224

Elimination of methane generated from landfills by biofiltration: a review  

Microsoft Academic Search

The production of biogas in landfills, its composition and the problems resulting from its generation are all reviewed. Biofiltration\\u000a is a promising option for the control of emissions to atmosphere of the methane contained in biogas issued from the smaller\\u000a and\\/or older landfills. A detailed review of the methane biofiltration literature is presented. The microorganisms, mainly\\u000a the methanotrophs, involved in

J. Nikiema; R. Brzezinski; M. Heitz

2007-01-01

225

FULL-SCALE EXPERIENCES WITH LEACHATE RECIRCULATING LANDFILLS: CASE STUDIES  

Microsoft Academic Search

Leachate recirculation has been shown in lysimeter, pilot-scale and full-scale investigations to reduce the time required for waste stabilization, improve leachate quality, provide the opportunity for leachate volume reduction, and to enhance the rate of gas production. New generation full-scale landfills are implementing recirculation as a leachate management tool with increasing frequency. Leachate recirculation techniques used at full-scale landfills include

Debra R. Reinhart

1996-01-01

226

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

227

Leachate treatment in landfills  

Microsoft Academic Search

This article describes the origins of sanitary landfill leachates, their potential for contamination of surrounding soil and groundwater, and characterization and techniques for treating this extremely high-strength municipal wastewater to required standards by biological processes. Topics include leachate characterization, effluent standards and treatment by two stage activated sludge process.

Zolten

1991-01-01

228

HAZARDOUS WASTE LANDFILL RESEARCH  

EPA Science Inventory

The hazardous waste land disposal research program is collecting data necessary to support implementation of disposal guidelines mandated by the 'Resource Conservation and Recovery Act of 1976' (RCRA) PL 94-580. This program relating to the categorical area of landfills, surface ...

229

Developments to a landfill processes model following its application to two landfill modelling challenges.  

PubMed

The landfill model LDAT simulates the transport and bio-chemical behaviour of the solid, liquid and gas phases of waste contained in a landfill. LDAT was applied to the LMC1 and LMC2 landfill modelling challenges held in 2009 and 2011. These were blind modelling challenges with the model acting in a predictive mode based on limited early time sections of full datasets. The LMC1 challenge dataset was from a 0.34m deep 0.48m diameter laboratory test cell, and the LMC2 dataset was from a 55m80m 8m deep landfill test cell which formed part of the Dutch sustainable landfill research programme at Landgraaf in the Netherlands. The paper describes developments in LDAT arising directly from the experience of responding to the two challenges, and discusses the model input and output data obtained from a calibration using the full datasets. The developments include the modularisation of the model into a set of linked sub-models, the strategy for converting conventional waste characteristics into model input parameters, the identification of flexible degradation pathways to control the CO2:CH4 ratio, and the application of a chemical equilibrium model that includes a stage in which the solid waste components dissolve into the leachate. PMID:23318154

White, J K; Beaven, R P

2013-10-01

230

3-D woven ceramic composite hot gas filter development  

SciTech Connect

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

Lane, J.E.; LeCostaouec, J.F., Westinghouse

1998-01-01

231

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

232

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

233

The use of engineered lightweight fill for landfill cover remediation  

SciTech Connect

In 1991, SCS was retained to provide design and construction engineering services to retrofit a landfill gas migration control system and regrade/repair an existing low-permeability soil final cover system for a 10-acre closed landfill located in west-central Florida. The final cover system modifications consisted of regrading the top of the landfill to re-establish positive drainage across and off of the top of the landfill. While active, the landfill had received municipal solid waste (MSW), commercial solid waste, and various industrial wastes and sludges. The landfill was closed in the early 1980`s. At the time of filling, the subject landfill was operated as a trench fill. A series of 40-foot deep trenches were excavated across the fill area, and the MSW was placed and compacted into the trenches. The soil excavated during construction of the trenches was used to construct berms along the sides of the individual trenches. No constructed bottom liner or leachate collection system was incorporated into the design. This report presents the results of a conceptual evaluation of utilizing expanded polystyrene blocks or Geofoam, as the lightweight fill component for an alternative cover remediation.

Poe, D.E.; Gardner, R.B.; Xiaoyu Fu

1995-12-31

234

Treatment of municipal landfill leachate using a combined anaerobic digester and activated sludge system  

Microsoft Academic Search

The main objective of this study was to assess the feasibility of treating sanitary landfill leachate using a combined anaerobic and activated sludge system. A high-strength leachate from Shiraz municipal landfill site was treated using this system. A two-stage laboratory-scale anaerobic digester under mesophilic conditions and an activated sludge unit were used. Landfill leachate composition and characteristics varied considerably during

S. Kheradmand; A. Karimi-Jashni; M. Sartaj

2010-01-01

235

Regional landfills methane emission inventory in Malaysia.  

PubMed

The decomposition of municipal solid waste (MSW) in landfills under anaerobic conditions produces landfill gas (LFG) containing approximately 50-60% methane (CH(4)) and 30-40% carbon dioxide (CO(2)) by volume. CH(4) has a global warming potential 21 times greater than CO(2); thus, it poses a serious environmental problem. As landfills are the main method for waste disposal in Malaysia, the major aim of this study was to estimate the total CH(4) emissions from landfills in all Malaysian regions and states for the year 2009 using the IPCC, 1996 first-order decay (FOD) model focusing on clean development mechanism (CDM) project applications to initiate emission reductions. Furthermore, the authors attempted to assess, in quantitative terms, the amount of CH(4) that would be emitted from landfills in the period from 1981-2024 using the IPCC 2006 FOD model. The total CH(4) emission using the IPCC 1996 model was estimated to be 318.8 Gg in 2009. The Northern region had the highest CH(4) emission inventory, with 128.8 Gg, whereas the Borneo region had the lowest, with 24.2 Gg. It was estimated that Pulau Penang state produced the highest CH(4) emission, 77.6 Gg, followed by the remaining states with emission values ranging from 38.5 to 1.5 Gg. Based on the IPCC 1996 FOD model, the total Malaysian CH( 4) emission was forecast to be 397.7 Gg by 2020. The IPCC 2006 FOD model estimated a 201 Gg CH(4) emission in 2009, and estimates ranged from 98 Gg in 1981 to 263 Gg in 2024. PMID:20858637

Abushammala, Mohammed F M; Noor Ezlin Ahmad Basri; Basri, Hassan; Ahmed Hussein El-Shafie; Kadhum, Abdul Amir H

2011-08-01

236

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

237

Update on Hilo Landfill Leachate TUpdate on Hilo Landfill Leachate TUpdate on Hilo Landfill Leachate TUpdate on Hilo Landfill Leachate TUpdate on Hilo Landfill Leachate Treatment Studyreatment Studyreatment Studyreatment Studyreatment Study continued on p  

E-print Network

Update on Hilo Landfill Leachate TUpdate on Hilo Landfill Leachate TUpdate on Hilo Landfill Leachate TUpdate on Hilo Landfill Leachate TUpdate on Hilo Landfill Leachate Treatment Studyreatment in the Hilo area it is anticipated that a substantial volume of leachate will be generated by any new landfill

238

THE USEPA'S LANDFILL RESEARCH AND REGULATORY STRATEGY  

EPA Science Inventory

The priorities and initiatives of Environmental Protection Agency's landfill research and regulatory program over the next five years will be described. This will include municipal solid waste landfills as well as abandoned hazardous waste landfills. Regarding municipals s...

239

CO gas sensing properties of ZnOCuO composite  

Microsoft Academic Search

In order to correct the reproducibility problem inherent in the hetero-contact gas sensor and to see the possibility of using the electrical composite material as a gas sensor, porous ZnO(n)CuO(p) composite system was selected for the investigation. The electrical conductivity and CO gas sensing properties were examined between 70 and 530C at a fixed relative humidity of 23%. ZnOCuO samples

Dang Hyok Yoon; Ji Haeng Yu; Gyeong Man Choi

1998-01-01

240

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.

241

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); Targos, William M. (Palatine, IL)

1987-01-01

242

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

243

INTERACTION BETWEEN GAS DIFFUSION AND MULTISTABLE HETEROGENEOUS CHEMICAL KINETICS IN C=C COMPOSITE  

E-print Network

brakes are frequently made of carbon/carbon (C=C) compos- ites. To deposit the composite interphaseINTERACTION BETWEEN GAS DIFFUSION AND MULTISTABLE HETEROGENEOUS CHEMICAL KINETICS IN C=C COMPOSITE PROCESSING G#19;erard L. VIGNOLES Universit#19;e Bordeaux 1, Laboratoire des Composites ThermoStructuraux 3

Recanati, Catherine

244

Goal-based waste management strategy to reduce persistence of contaminants in leachate at municipal solid waste landfills  

Microsoft Academic Search

The required minimum 30-year post-closure care period for municipal solid waste (MSW) landfills can be shortened by reducing\\u000a or eliminating of MSW components with long-terms effect in gas and leachate. The objectives of this study were to evaluate\\u000a the relative persistence of landfill gas, leachate quantity, and selected leachate parameters using post-closure monitoring\\u000a data from a case study landfill in

Berrin Tansel; Banu Sizirici Yildiz

2011-01-01

245

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

246

UV radiation of the GTA welding plasma versus shielding gas composition  

Microsoft Academic Search

UV radiation during gas tungsten arc (GTA) welding in argon\\/helium shielding gas mixtures versus gas composition and arc length has been investigated experimentally and theoretically. UV radiation was found to increase with an increase of argon concentration in the mixture. A physical model describing this phenomenon has been developed. The model predicts an increase in the total amount of ions

I. Ioffe; V. Koss; N. Perelman; D. Hilton

1997-01-01

247

Effects of Leachate Irrigation on Landfill Vegetation and Subsequent Methane Emissions  

Microsoft Academic Search

Short-rotation tree forests are irrigated with landfill leachate to reduce both leachate volume and nutrient content. It is of interest both for leachate treatment and energy recovery to optimise the productivity of such plantations. This study's aim was to investigate the effects of irrigation on soil quality, tree growth and on emissions of landfill gas (LFG) produced in the wastes.

C. Maurice; M. Ettala; A. Lagerkvist

1999-01-01

248

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

249

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.

250

Air emissions assessment and air quality permitting for a municipal waste landfill treating municipal sewage sludge  

SciTech Connect

This paper presents a case study into the air quality permitting of a municipal solid waste (MSW) landfill in the San Francisco Bay Area undergoing a proposed expansion in operations to increase the life of the landfill. The operations of this facility include MSW landfilling, the treatment and disposal of municipal sewage sludge, the aeration of petroleum-contaminated soils, the construction of a new on-site plant to manufacture soil amendment products from waste wood and other organic material diverted from the landfill, and the installation of a vaporator to create steam from leachate for injection into the landfill gas flare. The emissions assessment for each project component relied upon interpretation of source tests from similar operations, incorporation of on-site measurements into emissions models and mass balances, and use of AP-42 procedures for emissions sources such as wind-blown dust, material handling and transfer operations, and fugitive landfill gas. Air permitting issues included best available control technology (BACT), emission offset thresholds, new source performance standards (NSPS), potential air toxics health risk impacts, and compliance with federal Title V operating permit requirements. With the increasing difficulties of siting new landfills, increasing pressures to reduce the rate of waste placement into existing landfills, and expanding regulatory requirements on landfill operations, experiences similar to those described in this paper are likely to increase in the future as permitting scenarios become more complex.

Koehler, J. [Woodward-Clyde International -- Americas, Oakland, CA (United States)

1998-12-31

251

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

252

Superfund record of decision (EPA Region 3): Bush Valley Landfill Superfund Site, Harford County, Abingdon, MD, (final remedial action), September 26, 1995  

SciTech Connect

This Record of Decision (`ROD`) presents the final remedial action selected for the Bush Valley Landfill Superfund Site (`Site`), located near the town of Abingdon in Hardford County, Maryland. The remedial action selected for this Site is a final remedy which will address the wastes buried in the landfill, contaminated soils, leachate, landfill gas, the adjacent wetlands and streams, and contaminated ground water.

NONE

1995-10-01

253

Radioactivity and elemental analysis in the Ruseifa municipal landfill, Jordan.  

PubMed

In this study, a low background gamma-ray spectrometer based on a Hyper Pure Germanium detector was used to determine the activity concentrations of natural radionuclides in soil samples from various locations within the Ruseifa municipal landfill in Jordan. The chemical composition of the samples was also determined using a Wavelength Dispersive X-Ray Fluorescence Spectrometer. The maximum and minimum annual outdoor effective doses were found to be 103 and 36microSva(-1) in the old landfill and Abu-Sayaah village, respectively. The annual outdoor effective dose at the recent landfill site was found to be 91microSva(-1). The annual effective dose equivalents from outdoor terrestrial gamma radiation at the old landfill and the recent landfill were higher than the typical worldwide value of 70microSva(-1). Thus, some remediation of the soils on both old and recent landfills should be considered before any development for public activities. This could be achieved by mixing with clean soil from areas which are known to have lower radiation background. The concentration of heavy metals Zn, Cr, and Ba in the three sites included in this study were found to be higher than the background levels in the soil samples of the control area (Abu-Sayaah village). The enrichment factors for the above three elements were calculated and found to be: complex building site: Zn=2.52 and Ba=1.33; old landfill site: Cr=1.88, Zn=3.64, and Ba=1.26; and recent landfill site: Cr=1.57, Zn=2.19, and Ba=1.28. There was a strong negative correlation between the concentrations of the metallic elements (Mg, Al, Mn, Fe and Rb) and the concentrations of Zn, Ba, and Cr. Moreover, a strong positive correlation was found between Zn, Ba, and Cr. Thus these elements were enriched in the solid waste. PMID:18215446

Al-Jundi, J; Al-Tarazi, E

2008-01-01

254

Microstructure characterization of 3D C\\/SiC composites in combustion gas environments  

Microsoft Academic Search

C\\/SiC composites prepared by chemical vapor infiltration (CVI) were subjected to a stationary loading of 160 MPa in a combustion\\u000a gas environment with flame temperature of 1300 C. Lifetime of C\\/SiC composites in such environment was measured. Microstructures\\u000a of the composites after the testing were also characterized by SEM. The experimental results indicate the lifetime of C\\/SiC\\u000a composites is average

Jun Zhang; Xingang Luan; Litong Zhang

2010-01-01

255

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...

256

MONITORING GUIDANCE FOR BIOREACTOR LANDFILLS  

EPA Science Inventory

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

257

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.

258

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

259

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...

260

Water and element balances of landfills  

NASA Astrophysics Data System (ADS)

Municipal solid waste landfills represent an accumulation of material with less or more pollution potential. A part of this material is transfered to the environment by gas and leachate. To judge the environmental risk of landfills it is necessary to make statements about future emission streams. Today such statements are impossible but some less or more realistic estimations could be made. Results from different investigations are combined to extrapolate measured element transfer from an observed period into the future. Conclusions: -A decrease of leachate quantity could not be estimated. This is only possible with additional top sealing systems. -The most important emission stream over a long time is leachte. For many elements the period until concentrations below todays limiting values is some hundred years and more. The combination of decreasing concentration slopes with time and decreasing pollution limits could multiply the period of environmental risks. -The knowledge of processes in landfills in detail is too small. Therefore the presented results are only hypothesis without possibility of verification in an imaginable time. -A final storage quality defined as near zero pollution potential of solids and pollution stream of liquids cannot reached during the next centuries. The possibility of such defination should be verified under the view of whole mass transport in the environment.

Ehrig, H.-J.

261

Near Vent Volcanic Plume Measurement by a Portable Multi-Gas-Sensor System to Estimate Volcanic Gas Composition  

NASA Astrophysics Data System (ADS)

Near vent plume measurement technique by the use of the Portable Multi-Gas-Sensor System was developed to obtain volcanic gas composition of the major components including H2O, CO2, SO2, H2S and H2. By the combination with the Alkaline Filter Technique, the near vent plume measurement can provide almost full set of the volcanic gas composition including also HCl and HF. The Portable Multi-Gas-Sensor System measures concentration of the volcanic gas species by pumping the atmosphere (plume) through IR H2O-CO2 gas analyzer, SO2, H2S and H2 chemical sensors. The full system weight including battery and data logger is about 5 kg and can be easily carried in a backpack to the volcano summit. Among the various advantages and disadvantages of this techniques to other techniques such as the FT-IR measurements and the air-borne plume measurements with various gas analyzers, the most important advantage of the Portable Multi-Gas-Sensor System is the ability of the near vent measurement which enables the quantitative estimate of the H2O content in the volcanic gas. Since H2O content in the atmosphere is large and variable, a large mixing ratio of the volcanic gas in the plume is necessary to quantify the H2O excess over the atmospheric content. The atmospheric H2O content commonly ranges 5,000-20,000 ppm often with about 10% fluctuation whereas the CO2 content is about 370 ppm with minor (1 ppm) changes. Therefore we can quantify the excess CO2 content even at <1 ppm level, but we need at least 500 times larger excess H2O content derived from the volcanic gas for the quantification. By the near vent plume measurements, we could obtain the volcanic gas compositions of various volcanoes including Miyakejima, Asama and Villarrica as well as Etna whose gas composition is quite H2O-poor of H2O/CO2=1. Since H2O is commonly the most abundant volatile components both in the volcanic gases and magmas, and its solubility is quantitatively well constrained, the measured composition can provide important constraints to model the degassing processes.

Shinohara, H.

2006-12-01

262

Effects of natural gas composition on ignition delay under diesel conditions  

NASA Astrophysics Data System (ADS)

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.; Dijulio, S. S.; Westbrook, C. K.

1993-12-01

263

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

264

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

265

Perpetual landfilling through aeration of the waste mass; lessons from test cells in Georgia (USA).  

PubMed

Municipal solid waste (MSW) landfills worldwide are experiencing the consequences of conventional landfilling techniques, whereby anaerobic conditions are created within the landfilled waste. Under anaerobic conditions within a landfill site slow stabilization of the waste mass occurs, producing methane, (an explosive 'green house' gas) and leachate (which can pollute groundwater) over long periods of time. As a potential solution, it was demonstrated that the aerobic degradation of MSW within a landfill can significantly increase the rate of waste decomposition and settlement, decrease the methane production and leachate leaving the system, and potentially increase the operational life of the site. Readily integrated into the existing landfill infrastructure, this approach can safely and cost-effectively convert a MSW landfill from anaerobic to aerobic degradation processes, thereby effectively composting much of the organic portions (one of the potentially polluting elements in a conventional landfill site) of the waste. This paper summarizes the successful results of two separate aerobic landfill projects located in Georgia (USA) and discusses the potential economic and environmental impacts to worldwide solid waste management practices. PMID:11530917

Read, A D; Hudgins, M; Phillips, P

2001-01-01

266

Effects of shielding gas composition on arc profile and molten pool dynamics in gas metal arc welding of steels  

NASA Astrophysics Data System (ADS)

In gas metal arc welding, gases of different compositions are used to produce an arc plasma, which heats and melts the workpiece. They also protect the workpiece from the influence of the air during the welding process. This paper models gas metal arc welding (GMAW) processes using an in-house simulation code. It investigates the effects of the gas composition on the temperature distribution in the arc and on the molten pool dynamics in gas metal arc welding of steels. Pure argon, pure CO2 and different mixtures of argon and CO2 are considered in the study. The model is validated by comparing the calculated weld profiles with physical weld measurements. The numerical calculations reveal that gas composition greatly affects the arc temperature profile, heat transfer to the workpiece, and consequently the weld dimension. As the CO2 content in the shielding gas increases, a more constricted arc plasma with higher energy density is generated as a result of the increased current density in the arc centre and increased Lorentz force. The calculation also shows that the heat transferred from the arc to the workpiece increases with increasing CO2 content, resulting in a wider and deeper weld pool and decreased reinforcement height.

Wang, L. L.; Lu, F. G.; Wang, H. P.; Murphy, A. B.; Tang, X. H.

2014-11-01

267

Landfill Instability and Its Implications Operation, Construction, and Design  

E-print Network

of gas and leachate systems, relocation of access roads, temporary routing of storm water, and phase,000 cubic yard landfill failure involving leachate recirculation. Other failures of lesser magnitude also occurred involving liner systems during construction and waste containment closures. Recently an older

268

Gas flaring method and apparatus  

Microsoft Academic Search

This patent describes a method of flaring a gas mixture formed in a landfill. It comprises: withdrawing said gas mixture from said landfill; conducting said gas mixture to an annular burner comprised of an annular channel having sides and a bottom and a continuous top structure having a plurality of elongated flow passages therein configured such that said gas mixture

M. R. Keller; R. K. Noble; D. W. Pressnall

1990-01-01

269

Supplementary Data: Monosaccharide Composition and Linkage Analysis of RPS Glycosyl composition analysis was done by gas chromatography-mass  

E-print Network

composition analysis was done by gas chromatography-mass spectrometry (GC-MS) of the monosaccharide alditol in 4N TFA at 100o C (4 hr), resulting monosaccharides were reduced with NaBH4, acetylated in pyridine/acetic anhydride and analyzed on a DB-1 capillary column. Linkage analysis was done by GC-MS of the partially

Bush, C. Allen

270

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.

271

Sorption model of trichloroethylene (TCE) and benezene in municipal landfill materials  

E-print Network

This research is intended to establish a mathematical model describing the mass transfer of trace gas in landfill. Experimental data used for calibration were reported by Stiegler et al. [ 1989]. Transfer mechanisms of TCE and benzene (trace gases...

Chuang, Yuh-Lin

2012-06-07

272

Estimation of the Synergistic Effect Due to the Action of Composite Suppressants on Gas Combustion  

Microsoft Academic Search

A method is proposed to estimate synergistic effects that arises when composite suppressants act on propagation process of gas flames. This method is based on the assumption that the chemical and thermal constituents of the action of such suppressants on flammability limits are independent of each other. For complete description of the action of a composite suppressant, three parameters are

V. V. Zamashchikov; V. A. Bunev

2002-01-01

273

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

274

Different shake flask closures alter gas phase composition and ajmalicine production in Catharanthus roseus cell suspensions  

Microsoft Academic Search

The type of closure chosen for plant cell cultures can significantly alter the headspace gas composition of a culture, leading to major differences in the production of secondary metabolites. In cell suspension cultures of Catharanthus roseus, ethylene accumulated in cultures with limited gas exchange and appeared to inhibit the production of ajmalicine. The variability in product yields between replicates can

Carolyn W. T. Lee; Michael L. Shuler

1991-01-01

275

Soil gas composition provides evidence of in situ biodegradation of organic contaminants  

SciTech Connect

Soil gas within transport distance of aerobic biodegradation activity may be depleted in O{sub 2} and enriched in CO{sub 2}, compared to gas in similar uncontaminated sediments. This study compares soil gas composition at two uncontaminated control sites to a gasoline-contaminated site at which bacterial degradation of gasoline is suspected. At a site at Lawrence Livermore National Laboratory (LLNL), gasoline spilled before 1980 contaminates alluvial sediments to below the current water table (100 ft). Soil vapor was extracted intermittently from a multiply screened central well during 1988--90, possibly enhancing microbial activity. A microbiological study of other LLNL workers found bacteria populations, including in vitro gasoline degraders, to be much greater at the gasoline contaminated site than at the one control site they examined. Soil gas composition in the bacterially populated gasoline spill appears to be distinct from soil gas in nearby geologically similar uncontaminated sites. O{sub 2} concentrations is more distinct and more free from complicating factors than CO{sub 2}. Soil gas composition data indicate active bacterial respiration at the gasoline site. The gas composition and isotopic data provide evidence that supports existing microbial data suggesting that gasoline is being biodegraded at this site. In early investigations of a site, measurement of soil gas O{sub 2} and CO{sub 2} could provide an inexpensive first indicator of biodegradation activity. During and after remedial actions, these measurements might be used to help monitor biodegradation processes.

Camp, D.W.

1992-03-01

276

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

277

Findings from long-term monitoring studies at MSW landfill facilities with leachate recirculation.  

PubMed

This paper presents findings from long-term monitoring studies performed at full-scale municipal solid waste landfill facilities with leachate recirculation. Data from two facilities at a landfill site in Delaware, USA were evaluated as part of this study: (1) Area A/B landfill cells; and (2) two test cells (one with leachate recirculation and one control cell). Data from Area A/B were compared with proposed waste stability criteria for leachate quality, landfill gas production, and landfill settlement. Data from the test cells were directly compared with each other. Overall, the trends at Area A/B pointed to the positive effects (i.e., more rapid waste degradation) that may be realized through increasing moisture availability in a landfill relative to the reported behavior of more traditionally operated (i.e., drier) landfills. Some significant behavioral differences between the two test cells were evident, including dissimilarities in total landfill gas production quantity and the extent of waste degradation observed in recovered time capsules. Differences in leachate quality were not as dramatic as anticipated, probably because the efficiency of the leachate recirculation system at distributing leachate throughout the waste body in the recirculation cell was low. PMID:12957160

Morris, J W F; Vasuki, N C; Baker, J A; Pendleton, C H

2003-01-01

278

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

279

Thermal-shock behavior of advanced ceramic\\/composite hot-gas filters  

Microsoft Academic Search

The thermal shock\\/fatigue behavior of monolithic and composite hot-gas candle filters obtained from various manufacturers was evaluated. The composite filters were made of both oxide and nonoxide materials; the monolithic filters were made only of nonoxide materials. During single-cycle thermal shock tests, composite filters show little or no strength degradation when quenched from temperatures between 900 and 1000°C. At higher

J. P. Singh; M. Sutaria; W. Bielke

1997-01-01

280

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 Parishs 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

281

LANDFILL CONTAINMENT AND COVER SYSTEMS  

EPA Science Inventory

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

282

Compositional discrimination of decompression and decomposition gas bubbles in bycaught seals and dolphins.  

PubMed

Gas bubbles in marine mammals entangled and drowned in gillnets have been previously described by computed tomography, gross examination and histopathology. The absence of bacteria or autolytic changes in the tissues of those animals suggested that the gas was produced peri- or post-mortem by a fast decompression, probably by quickly hauling animals entangled in the net at depth to the surface. Gas composition analysis and gas scoring are two new diagnostic tools available to distinguish gas embolisms from putrefaction gases. With this goal, these methods have been successfully applied to pathological studies of marine mammals. In this study, we characterized the flux and composition of the gas bubbles from bycaught marine mammals in anchored sink gillnets and bottom otter trawls. We compared these data with marine mammals stranded on Cape Cod, MA, USA. Fresh animals or with moderate decomposition (decomposition scores of 2 and 3) were prioritized. Results showed that bycaught animals presented with significantly higher gas scores than stranded animals. Gas composition analyses indicate that gas was formed by decompression, confirming the decompression hypothesis. PMID:24367623

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

2013-01-01

283

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

284

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...

285

Nitrogen management in bioreactor landfills  

Microsoft Academic Search

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 NO3-N \\/l every 48 h for periods of 1959 days.

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

2003-01-01

286

Recirculation of municipal landfill leachate  

E-print Network

aerobic decomposition of the leachate on the surface in addition to the anaer obic decomposition of the leachate within the landfill and the increased efficiency due to recirculation. HETHODS Each of the experimental landfi 1 1 cel is, as constructed... aerobic decomposition of the leachate on the surface in addition to the anaer obic decomposition of the leachate within the landfill and the increased efficiency due to recirculation. HETHODS Each of the experimental landfi 1 1 cel is, as constructed...

Pinkowski, Brian Jude

2012-06-07

287

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 350C. PMID:24473403

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

2014-03-15

288

Settlement Prediction, Gas Modeling and Slope Stability Analysis  

E-print Network

Settlement Prediction, Gas Modeling and Slope Stability Analysis in Coll Cardús Landfill Li Yu using mechanical models Simulation of gas generation, transport and extraction in MSW landfill 1 models Simulation of gas generation, transport and extraction in MSW landfill 1) Analytical solution

Politècnica de Catalunya, Universitat

289

Enhanced Landfill Mining case study: Innovative separation techniques  

NASA Astrophysics Data System (ADS)

In 2011, a corporate vision on Enhanced Landfill Mining (ELFM)1 was approved by the OVAM Board of directors, which resulted in an operational programme over the period 2011-2015. OVAM (Public Waste Agency of Flanders) is the competent authority in charge of waste, Sustainable Materials Management (SMM) and contaminated soil management in Flanders. The introduction of the ELFM concept needs to be related with the concept of SMM and the broader shift to a circular economy. Within the concept of ELFM, landfills are no longer considered to be a final and static situation, but a dynamic part of the materials cycle. The main goal of this research programme is to develop a comprehensive policy on resource management to deal with the issue of former landfills. In order to investigate the opportunities of ELFM, the OVAM is applying a three step approach including mapping, surveying and mining of these former landfills. As a result of the mapping part over 2,000 landfill sites, that will need to be dealt with, were revealed. The valorisation potential of ELFM could be assigned to different goals, according to the RP-concept : Recycling of Materials, Recovery of Energy, Reclamation of Land and Protection of drinking water supply. . On behalf of the OVAM, ECOREM was assigned to follow-up a pilot case executed on a former landfill, located in Zuienkerke, Flanders. Within this case study some technical tests were carried out on the excavated waste material to investigate the possibilities for a waste to resource conversion. The performance of both on site and off site techniques were evaluated. These testings also contribute to the mapping part of OVAM's research programme on ELFM and reveal more information on the composition of former landfills dating from different era's. In order to recover as many materials as possible, five contractors were assigned to perform separation tests on the bulk material from the Zuienkerke landfill. All used techniques were described, resulting in a separate flowsheet for every contractor. The resulting fractions and materials were described in detail to obtain an inventory of the bulk material. Based on the characteristics from the obtained fractions, all possible valorisation pathways are listed, suggesting a Waste to Material (WtM) or a Waste to Energy (WtE) valorisation pathway. Fractions that needed further treatment were also discussed. The results of the separation tests proved to be very promising and delivered well sorted waste streams. The composition of the waste material, on the other hand, proved to be less beneficial to be economically feasible. Due to the high amount of sand and clay (up to 90wt%) in the Zuienkerke landfill the share of instant recoverable materials proved to be very limited. Due to the limited number of tests concerning the separation and valorisation of landfilled waste, the feasibility of ELFM in the short term is not fully described yet. Based on the first experiences, the main drivers to introduce the ELFM concept on these type of landfills are the necessity of urgent remediation actions and the reclamation of land. The added value of land reuse for the future might close the financial gap in a significant way, making the implementation of ELFM feasible on former landfills. 1 Jones et al.,2010: "the safe conditioning, excavation and integrated valorisation of landfilled waste streams as both materials and energy, using innovative transformation technologies and respecting the most stringent social and ecological criteria".

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

2014-05-01

290

NOVEL COMPOSITE MEMBRANES AND PROCESS FOR NATURAL GAS UPGRADING  

SciTech Connect

In the second phase of this project, the newly developed membrane module for natural gas dehydration was tested and evaluated in a pilot plant located at a commercial natural gas treatment site. This phase was undertaken jointly with UOP LLC, our commercialization partner. The field test demonstrated that a commercial-size membrane module for natural gas dehydration was successfully manufactured. The membrane module operated reliably over 1000 psi differential pressure across the membrane in the field test. The effects of feed gas pressure, permeate gas pressure, feed flow rate, purge ratio (flow rate ratio of permeate outlet to feed), and feed gas dew point on the membrane module performance were determined and found to meet the design expectations. Although water vapor permeance was lower than expected, substantial natural gas dehydration was demonstrated with low purge ratio. For example, dew point was suppressed by as much as 30 F with only about 2 {approx} 3% purge ratio. However the bore side pressure drops were significantly higher than the projected value from the fluid dynamic calculation. It is likely that not all the fibers were open in either the sweep or the permeate tube sheet end. This could help to explain the relatively low water vapor permeances that were measured in the field. An economic evaluation of the membrane process and the traditional Triethylene Glycol (TEG) process to dehydrate natural gas was performed and the economics of the two processes were compared. Two sets of membrane module performance properties were used in the economic analysis of the membrane process. One was from the results of this field test and the other from the results of the previous small-scale test with a medium pressure membrane variant conducted at 750 psig. The membrane process was competitive with the TEG process for the natural gas feed flow rate below 10 MMSCFD for the membrane with previously measured water vapor permeance. The membrane process was competitive for the feed flow rate below 1 MMSCFD even for the membrane with the water vapor permeance of this field test.

Ben Bikson; Sal Giglia; Jibin Hao

2003-03-01

291

Behavior of stabilized fly ashes in solid waste landfills  

SciTech Connect

In Japan, the fly ash generated by incineration of municipal solid waste has come to be handled as general waste under special management in recent years. At the same time, direct landfilling or ocean dumping of fly ash is legally prohibited. To avoid the possibility of causing damages affecting human health or life environment, fly ash must be subjected to intermediate treatment, and must be stabilized, encapsulated and made hygienic by removing pollutants. Four methods can be given for fly ash intermediate treatment: (1) cement solidification, (2) treatment by chemicals, (3) acid and other solvents and (4) melting and solidification. On the other hand, various phenomena affecting fly ash occur on the landfilled waste layer, such as generation of organic acid and carbon dioxide gas due to decomposition of solid waste. Fly ash solidified by cement is deteriorated by water-soluble sulfate and organic acid and carbon dioxide gas produced by decomposition of organic substances in the municipal solid waste. This may result in a reduced strength of hazardous substances and re-melting of fly ash solidified by cement. Furthermore, encapsulated hazardous heavy metals may be eluted from fly ash treated by chemicals due to the change in chemical environments in the landfilled solid waste layer according to stabilization of the landfilled solid waste. In this present study, the large-sized landfill model lysimeter is filled with cement-solidified fly ash or chemically treated fly ash treated together with municipal solid waste to obtain correct information on the changes in the physical and chemical properties of the cement-solidified fly ash, and temporal concentration of hazardous substances contained in seepage leachate or leachate in the landfilled solid waste layer, thereby clarifying the long-term stability of the disposed fly ash.

Shimaoka, Takayuki; Hanashima, Masataka [Fukuoka Univ. (Japan). Dept. of Civil Engineering] [Fukuoka Univ. (Japan). Dept. of Civil Engineering

1996-12-31

292

The best MSW treatment option by considering greenhouse gas emissions reduction: a case study in Georgia.  

PubMed

The grave concern over climate change and new economic incentives such as the clean development mechanism (CDM) have given more weight to the potential of projects for reducing greenhouse gas (GHG) emissions. In the Adjara solid waste management project, even though the need for reductions in GHG emissions is acknowledged, it is not one of the key factors for selecting the most appropriate treatment method. This study addresses the benefit of various solid waste treatment methods that could be used in the Adjara project in terms of reducing GHG emissions. Seven different options for solid waste treatment are examined: open dumping as the baseline case, four options for landfill technology (no provision of landfill gas capture, landfill gas capture with open flare system, with enclosed flare system and with electricity generation), composting and anaerobic digestion with electricity production. CDM methodologies were used to quantify the amount of reductions for the scenarios. The study concludes sanitary landfill with capture and burning of landfill gas by an enclosed flare system could satisfy the requirements, including GHG reduction potential. The findings were tested for uncertainty and sensitivity by varying the data on composition and amount of waste and were found to be robust. PMID:21382876

Tayyeba, Omid; Olsson, Monika; Brandt, Nils

2011-08-01

293

Uncontrolled methane emissions from a MSW landfill surface: influence of landfill features and side slopes.  

PubMed

Sanitary landfills for Municipal Solid Waste (MSW) disposal have been identified as one of the most important anthropogenic sources of methane (CH4) emissions; in order to minimize its negative effects on the environment, landfill gas (LFG) recovery is a suitable tool to control CH4 emissions from a landfill site; further, the measurement of CH4 emissions can represent a good way to evaluate the effectiveness of LFG recovering systems. In general, LFG will escape through any faults in the landfill capping or in the LFG collection system. Indeed, some areas of the capping can be more permeable than others (e.g. portions of a side slope), especially when considering a temporarily capped zone (covered area that is not expected to receive any further waste for a period of at least 3 months, but for engineering reasons does not have a permanent cap yet). These areas, which are characterized by abnormal emissions, are usually defined as "features": in particular, a feature is a small, discrete area or an installation where CH4 emissions significantly differ from the surrounding zones. In the present study, the influence that specific features have on CH4 emissions has been investigated, based on direct measurements carried out in different seasons by means of a flux chamber to the case study of Palermo (IT) landfill (Bellolampo). The results showed that the flux chamber method is reliable and easy to perform, and the contoured flux maps, obtained by processing the measured data were found to be a suitable tool for identifying areas with abnormal (high) emissions. Further, it was found that a relationship between methane emission rates and landfill side slope can be established. Concerning the influence of the temporary HDPE cover system on CH4 recovery efficiency, it contributed to a significant decrease of the free surface area available for uncontrolled emissions; this aspect, coupled to the increase of the CH4 volumes collected by the LFG recovery system, led to a significant increase of the recovery efficiency. PMID:23465313

Di Trapani, Daniele; Di Bella, Gaetano; Viviani, Gaspare

2013-10-01

294

Correlation between gas molecular weight, heating value and sonic speed under variable compositions of natural gas  

Microsoft Academic Search

A simulation study of likely uncertainties in molecular weight and heating value of the gas mixture as predicted from measured or calculated sonic speed. The sonic speed, molecular weight and heating value of natural gas were studied as a function of random fluctuation of the gas fractions. A method of sonic speed prediction was developed and used for over 50,000

L. Burstein; D. Ingman; Y. Michlin

1999-01-01

295

Gas composition in the annealing zone and glass working properties  

Microsoft Academic Search

The composition of the atmosphere in the glass shaping zone has a marked effect on the surface-layer structure and properties. The various gases have individual effects in reducing the excess energy. One can vary the ratios or introduce new gases or vapor to suppress or activate various surface processes [i]. However, structure formation does not cease below the vitrification temperature,

A. V. Gorokhovskii; K. V. Polyakov

1991-01-01

296

Potential applications of structural ceramic composites in gas turbines  

Microsoft Academic Search

This paper reports that a Babcock and Wilcox-Solar Turbines Team has completed a program to assess the potential for structural ceramic composites in turbines for direct coal-fired or coal gasification environments. A review is made of the existing processes in direct coal firing, pressurized fluid bed combustors, and coal gasification combined cycle systems. Material requirements in these areas were also

W. P. Jr. Parks; R. R. Ramey; D. C. Rawlins; J. R. Price; M. Van Roode

1991-01-01

297

PRACTICE REVIEW OF FIVE BIOREACTOR/RECIRCULATION LANDFILLS  

EPA Science Inventory

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

298

Constraints on the origins of hydrocarbon gas from compositions of gases at their site of origin  

PubMed

It is widely accepted that natural gas is formed from thermal decomposition of both oil in reservoirs and, to a lesser extent, the organic matter in shales from which the oil was derived. But laboratory pyrolysis experiments on shales do not reproduce the methane-rich composition typical of most gas reservoirs, leading to suggestions that other mechanisms, such as transition-metal catalysis, may be important. The discrepancy might, however, instead arise because gas (and oil) deposits have migrated from their source rocks, so that the reservoir composition might not be representative of the composition in the source rocks where the hydrocarbons were generated. To address this question, we have analysed gas samples coproduced with oils directly from a source rock (the Bakken shales, North Dakota, USA) where the local geology has prevented significant hydrocarbon migration. The methane contents of these Bakken-shale gases are much lower than that of conventional gas reservoirs, but are consistent with that from pyrolysis experiments on these shales. Thus, because these Bakken gases form with (rather than from) oils, we argue that compositional differences between gases from source rocks and conventional gas deposits result from fractionation processes occurring after hydrocarbon expulsion from the source rock. PMID:11536709

Price, L C; Schoell, M

1995-11-23

299

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

PubMed

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

Raga, Roberto; Cossu, Raffaello

2014-03-01

300

Decompression vs. Decomposition: Distribution, Amount, and Gas Composition of Bubbles in Stranded Marine Mammals  

PubMed Central

Gas embolic lesions linked to military sonar have been described in stranded cetaceans including beaked whales. These descriptions suggest that gas bubbles in marine mammal tissues may be more common than previously thought. In this study we have analyzed gas amount (by gas score) and gas composition within different decomposition codes using a standardized methodology. This broad study has allowed us to explore species-specific variability in bubble prevalence, amount, distribution, and composition, as well as masking of bubble content by putrefaction gases. Bubbles detected within the cardiovascular system and other tissues related to both pre- and port-mortem processes are a common finding on necropsy of stranded cetaceans. To minimize masking by putrefaction gases, necropsy, and gas sampling must be performed as soon as possible. Before 24?h post mortem is recommended but preferably within 12?h post mortem. At necropsy, amount of bubbles (gas score) in decomposition code 2 in stranded cetaceans was found to be more important than merely presence vs. absence of bubbles from a pathological point of view. Deep divers presented higher abundance of gas bubbles, mainly composed of 70% nitrogen and 30% CO2, suggesting a higher predisposition of these species to suffer from decompression-related gas embolism. PMID:22675306

de Quiros, Yara Bernaldo; Gonzalez-Diaz, Oscar; Arbelo, Manuel; Sierra, Eva; Sacchini, Simona; Fernandez, Antonio

2012-01-01

301

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

EPA Science Inventory

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

302

Decomposition of forest products buried in landfills.  

PubMed

The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C+H) loss of up to 38%, while loss for the other wood types was 0-10% in most samples. The C+H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27gOCg(-1) dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than previously reported. PMID:23942265

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

2013-11-01

303

Research and Development Work Concerning the Separation of Helium from Gas Mixtures by SiO2 Composite Membranes.  

National Technical Information Service (NTIS)

Methods for the selective separation of helium from natural gas as an alternative to natural gas liquefaction was investigated. Composite membranes were examined for their usefulness for the separation of helium from a methane helium mixture. These compos...

W. Kreiger, P. Wiessart

1982-01-01

304

Research and Development Work Concerning the Separation of Helium from Gas Mixtures by SiO sub 2 Composite Membranes.  

National Technical Information Service (NTIS)

The demand for helium is continuously rising, so that methods for the selective separation of helium from natural gas are gaining increasing importance as an alternative to natural gas liquefaction. Composite membranes were examined for their usefulness f...

W. Krieger, P. Wiesert

1982-01-01

305

Gas-desulfurization plant handles wide range of sour gas compositions  

SciTech Connect

The Nederlandse Aardolie Maatschappij B.V. (NAM) gas desulfurization facilities at Emmen treat a natural gas feed containing H{sub 2}S, CO{sub 2}, and mercaptans, to tight pipeline specifications. This paper reports on the highly selective Sulfinol-M solvent which enables the plant to treat natural gases with a CO{sub 2}/H{sub 2}S ratio as high as 25:1, while producing an acid- gas feed suitable for a conventional Claus unit. To help meet the stringent environmental regulations, an integrated Shell Claus off-gas treating (SCOT) unit achieves an overall sulfur recovery of better than 99.8%.

Taylor, N.A.; Augill, J.A. (Shell Internationale Research Maatschappij NV, The Hague (Netherlands)); van Kessel, M.M.; Verburg, R.P.J. (Nederlandse Aardolie, Maatschappij B.V., Emmen (NL))

1991-08-19

306

IMPACT ASSESSMENT OF THE OLD QUESNEL LANDFILL  

E-print Network

#12;IMPACT ASSESSMENT OF THE OLD QUESNEL LANDFILL FINAL REPORT DOE FRAP 1995-05 Prepared for .................................................................................................................ll Leachate Seeps List of Figures Site Location/Legal Boundary Old Quesnel Landfill

307

Temperature-dependent gas transport performance of vertically aligned carbon nanotube/parylene composite membranes  

NASA Astrophysics Data System (ADS)

A novel composite membrane consisting of vertically aligned carbon nanotubes (CNTs) and parylene was successfully fabricated. Seamless filling of the spaces in CNT forests with parylene was achieved by a low-pressure chemical vapor deposition (CVD) technique and followed with the Ar/O2 plasma etching to expose CNT tips. Transport properties of various gases through the CNT/parylene membranes were explored. And gas permeances were independent on feed pressure in accordance with the Knudsen model, but the permeance values were over 60 times higher than that predicted by the Knudsen diffusion kinetics, which was attributed to specular momentum reflection inside smooth CNT pores. Gas permeances and enhancement factors over the Knudsen model firstly increased and then decreased with rising temperature, which confirmed the existence of non-Knudsen transport. And surface adsorption diffusion could affect the gas permeance at relatively low temperature. The gas permeance of the CNT/parylene composite membrane could be improved by optimizing operating temperature.

Zhang, Lei; Yang, Junhe; Wang, Xianying; Zhao, Bin; Zheng, Guangping

2014-08-01

308

Temperature-dependent gas transport performance of vertically aligned carbon nanotube/parylene composite membranes  

PubMed Central

A novel composite membrane consisting of vertically aligned carbon nanotubes (CNTs) and parylene was successfully fabricated. Seamless filling of the spaces in CNT forests with parylene was achieved by a low-pressure chemical vapor deposition (CVD) technique and followed with the Ar/O2 plasma etching to expose CNT tips. Transport properties of various gases through the CNT/parylene membranes were explored. And gas permeances were independent on feed pressure in accordance with the Knudsen model, but the permeance values were over 60 times higher than that predicted by the Knudsen diffusion kinetics, which was attributed to specular momentum reflection inside smooth CNT pores. Gas permeances and enhancement factors over the Knudsen model firstly increased and then decreased with rising temperature, which confirmed the existence of non-Knudsen transport. And surface adsorption diffusion could affect the gas permeance at relatively low temperature. The gas permeance of the CNT/parylene composite membrane could be improved by optimizing operating temperature.

2014-01-01

309

Astronomy on a Landfill  

NASA Astrophysics Data System (ADS)

Engaging "K-to-Gray audiences (children, families, and older adults) in astronomical activities is one of the main goals of the NJMC Center for Environmental and Scientific Education and the William D. McDowell Observatory located in Lyndhurst, NJ. Perched atop a closed and reclaimed municipal solid waste landfill, our new LEED - certified building (certification pending) and William D. McDowell observatory will assist in bringing the goals of IYA 2009 to the approximately 25,000 students and 3,000 adults that visit our site from the NY/NJ region each year. Diversifying our traditional environmental science offerings, we have incorporated astronomy into our repertoire with "The Sun Through Time module, which includes storytelling, cultural astronomy, telescope anatomy, and other activities that are based on the electromagnetic spectrum and our current knowledge of the sun. These lessons have also been modified to bring astronomy to underserved communities, specifically those individuals that have dexterity or cognitive ability differences. The program is conducted in a classroom setting and is designed to meet New Jersey Core Curriculum Content Standards. With the installation of our new 20 telescope, students and amateur astronomers will be given the opportunity to perform rudimentary research. In addition, a program is in development that will allow individuals to measure local sky brightness and understand the effects of light pollution on astronomical viewing. Teaching astronomy in an urban setting presents many challenges. All individuals, regardless of ability level or location, should be given the opportunity to be exposed to the wonders of the universe and the MEC/CESE has been successful in providing those opportunities.

Venner, Laura

2008-05-01

310

Astronomy on a Landfill  

NASA Astrophysics Data System (ADS)

Engaging "K-to-Gray audiences (children, families, and older adults) in astronomical activities is one of the main goals of the NJMC Center for Environmental and Scientific Education and the William D. McDowell Observatory located in Lyndhurst, NJ. Perched atop a closed and reclaimed municipal solid waste landfill, our new LEED - certified building (certification pending) and William D. McDowell observatory will assist in bringing the goals of IYA 2009 to the approximately 25,000 students and 15,000 adults that visit our site from the NY/NJ region each year. Diversifying our traditional environmental science offerings, we have incorporated astronomy into our repertoire with "The Sun Through Time module, which includes storytelling, cultural astronomy, telescope anatomy, and other activities that are based on the electromagnetic spectrum and our current knowledge of the sun. These lessons have also been modified to bring astronomy to underserved communities, specifically those individuals that have dexterity or cognitive ability differences. The program is conducted in a classroom setting and is designed to meet New Jersey Core Curriculum Content Standards. With the installation of our new 20 telescope, students and amateur astronomers will be given the opportunity to perform rudimentary research. In addition, a program is in development that will allow individuals to measure local sky brightness and understand the effects of light pollution on astronomical viewing. Teaching astronomy in an urban setting presents many challenges. All individuals, regardless of ability level or location, should be given the opportunity to be exposed to the wonders of the universe and the MEC/CESE has been successful in providing those opportunities.

Venner, Laura

2008-09-01

311

Real-time Multi-GAS sensing of volcanic gas composition: experiences from the permanent Etna and Stromboli networks  

NASA Astrophysics Data System (ADS)

Measuring the composition of volcanic gases released from active volcanoes brings profound insights into our understanding of volcanic processes and, when combined with other methods, contributes to volcano monitoring. Volcanic gases can now be measured with a large variety of highly sophisticated techniques, but high-resolution routine measurements are possible with only a few of them (e.g., FTIR), and typically for only a few compounds. The Multi-GAS (Multi-component Gas Analyser System) technique has recently been demonstrated as a powerful method for the real-time high-resolution measurement of volcanic gas plumes, as has been used for discrete measurement surveys at several volcanoes including, among others, Etna, Stromboli and Vulcano in Italy, Villarica in Chile, Masaya in Nicaragua, Yasur and Ambrym in Vanuatu Republic, Miyakejima and Asama in Japan, and Soufriere Hill volcano on Montserrat. More recently, permanent Multi-GAS devices have been installed for the first on an active volcano at Etna (in 2004) and Stromboli (in 2006), allowing for the acquisition of unprecedented accurate time-series of volcanic gas compositions (for the three major components CO2-SO2-H2O) at both volcanoes. Here, we review the results of such permanent MultiGAS networks, and we demonstrate their implications for the comprehension of volcanic degassing processes. We also show that cycles of increase of Multi-GAS-sensed CO2/SO2 ratios preceded the most recent eruptive episodes on Etna in 2006-2008 and Stromboli in 2007, providing us with valuable precursor information on magma ascent within the shallow plumbing systems of these very active volcanoes, and thus deeply contributing to volcano hazard mitigation.

Liuzzo, M.; Aiuppa, A.; Giudice, G.; Gurrieri, S.

2009-04-01

312

Pollution profiles and physicochemical parameters in old uncontrolled landfills.  

PubMed

The long-term effectiveness of the geological barrier beneath municipal-waste landfills is a critical issue for soil and groundwater protection. This study examines natural clayey soils directly in contact with the waste deposited in three landfills over 12 years old in Spain. Several physicochemical and geological parameters were measured as a function of depth. Electrical conductivity (EC), water-soluble organic carbon (WSOC), Cl(-), NH(4)(+), Na(+) and exchangeable NH(4)(+) and Na(+) were used as parameters to measure the penetration of landfill leachate pollution. Mineralogy, specific surface area and cationic-exchange capacities were analyzed to characterize the materials under the landfills. A principal component analysis, combined with a Varimax rotation, was applied to the data to determine patterns of association between samples and variables not evident upon initial inspection. The main factors explaining the variation in the data are related to waste composition and local geology. Although leachates have been in contact with clays for long time periods (13-24 years), WSOC and EC fronts are attenuated at depths of 0.2-1.5m within the clay layer. Taking into account this depth of the clayey materials, these natural substrata (>45% illite-smectite-type sheet silicates) are suitable for confining leachate pollution and for complying with European legislation. This paper outlines the relevant differences in the clayey materials of the three landfills in which a diffusive flux attenuation capacity (A(c)) is defined as a function (1) of the rate of decrease of the parameters per meter of material, (2) of the age and area of the landfill and (3) of the quantity and quality of the wastes. PMID:22169764

Regado, M; Ruiz, A I; de Soto, I S; Rastrero, M Rodriguez; Snchez, N; Gismera, M J; Sevilla, M T; da Silva, P; Procopio, J Rodrguez; Cuevas, J

2012-03-01

313

Kr-81 terrestrial ages and grouping of Yamato eucrites based on noble gas and chemical compositions  

NASA Astrophysics Data System (ADS)

The ages of Yamato eucrites recovered in Antarctia, and terrestrial ages of nine Yamato eucrites (Y-75011, Y-791826, Y-792511, Y-793164, Y-793547, Y-793548, Y-793570, Y-794002, and Y-794043) were determined based on cosmic-ray produced Kr-81. Based on the terrestrial ages, cosmic-ray exposure ages, noble gas compositions, and chemical compositions, groupings of these Yamato eucrites were established.

Miura, Y.; Nagao, K.; Fujitani, T.

1993-04-01

314

Separation of gases through gas enrichment membrane composites  

DOEpatents

Thin film composite membranes having as a permselective layer a film of a homopolymer of certain vinyl alkyl ethers are useful in the separation of various gases. Such homopolymers have a molecular weight of greater than 30,000 and the alkyl group of the vinyl alkyl monomer has from 4 to 20 carbon atoms with branching within the alkyl moiety at least at the carbon atom bonded to the ether oxygen or at the next adjacent carbon atom. These membranes show excellent hydrolytic stability, especially in the presence of acidic or basic gaseous components.

Swedo, Raymond J. (Mt. Prospect, IL); Kurek, Paul R. (Schaumburg, IL)

1988-01-01

315

Separation of gases through gas enrichment membrane composites  

DOEpatents

Thin film composite membranes having as a permselective layer a film of a homopolymer of certain vinyl alkyl ethers are useful in the separation of various gases. Such homopolymers have a molecular weight of greater than 30,000 and the alkyl group of the vinyl alkyl monomer has from 4 to 20 carbon atoms with branching within the alkyl moiety at least at the carbon atom bonded to the ether oxygen or at the next adjacent carbon atom. These membranes show excellent hydrolytic stability, especially in the presence of acidic or basic gaseous components.

Swedo, R.J.; Kurek, P.R.

1988-07-19

316

Variation of Volcanic Gas Composition at a Persistently Degassing Asama Volcano, Japan  

NASA Astrophysics Data System (ADS)

Asama volcano at central Japan is a persistently degassing andesitic volcano and repeated eruptions every several years. The recent eruptions occurred in September 2004, August 2008 and February 2009 and are followed by increase of the volcanic gas emission during several months. The SO2 flux is typically 1,000-4,000 t/d during the high flux period after the eruption, whereas the flux is around 100 t/d during the low gas flux periods (JMA, 2013; Ohwada et al., in review). This study aims to understand the controlling process of volcano degassing based on the volcanic gas composition data. In particular, we focus to evaluate the gas composition contrast between the high and low gas flux periods. As the fumaroles and degassing vent locate in the summit crater of 500-m-diamter and are inaccessible, we estimated the gas composition by plume measurements with the Multi-GAS at the crater rim. The HCl/SO2 ratios are obtained by the alkali-filter trap. We started the repeat Multi-GAS measurements in 2004 and installed an automatic Multi-GAS monitoring station for a daily measurement at the western rim of the summit crater in 2010. The gas compositions obtained by the Multi-GAS measurements are often scattered even during the day of measurements, in particular during the low flux period and the scatter is likely due to variable contamination of gases from low-temperature fumaroles locating along the crater rim because the low-temperature fumaroles locate closer to the measurement site that the major degassing vent at the bottom of the crater. If we plot the gas concentration ratio, such as CO2/SO2 against SO2 concentration, the ratio commonly converges to a certain value at high SO2 concentration and this ratio is considered as representative of the major gas emission. The estimated molar ratios are CO2/SO2=10.5, HCl/SO2=0.20.1 and H2O/SO2=6030 without clear contrast during the high and low flux periods. The CO2/SO2 ratios obtained based on a single day data tend to be higher than the average, however, the analyses with a larger data set, e.g., for a month, results in the average value. The HCl/SO2 ratios agree well with those obtained during the 2004 eruptive period by FT-IR and ash-leachate analyses with the range of 0.15-0.2 and 0.1-0.2, respectively (Mori and Notsu, 2005; Nogami et al., 2004). The H2O/SO2 ratios also tend to be higher during the low flux period and this can be due to a larger contribution of meteoric water during the low flux period. The constant gas composition regardless of the large variation of the gas flux suggests that the degassing process and its condition remains the same for the high and low flux periods. The similar HCl/SO2 ratio obtained during both the eruptive period by FT-IR and ash leachate and the persistent degassing stage in this study indicates that persistent degassing is fed by low pressure gas separation from continuously ascending magmas, consistent with the conduit magma convection model (Ohwada et al., in review; Shinohara, 2008). Based on the conduit magma convection model, the large flux changes without variation of the gas composition can be caused by the change of the magma convection rate with similar degassing pressure and magma composition.

Shinohara, H.; Ohminato, T.; Takeo, M.

2013-12-01

317

Compliant Sanitary Landfill Model and Construction  

NSDL National Science Digital Library

This activity from ATEEC requires students to build a three dimensional and compliant landfill model. The purpose of the activity is to "allow students to learn about proper landfill construction and compliance using simple, easily obtainable items." The landfill model must incorporate solid waste federal regulations. This document includes a list of the materials needed and a diagram of a landfill.

2014-07-18

318

Geosynthetics conquer the landfill law  

SciTech Connect

Los Angeles' last operating landfill is undergoing a 4 million m[sup 3] expansion using innovative materials in the liner system to overcome difficult site conditions. The design represents the first approved alternative in California -- and perhaps in the nation -- to the Resource Conservation and Recovery Act's Subtitle D regulations for liner systems. This article examines the regulatory journey that led to approval and the liner's design and construction. Steep slopes at Los Angeles' only operating municipal solid-waste landfill (MSW) forced designers to use an innovative geosynthetic liner and leachate collection system. Its use sets a precedent for alternatives to the prescriptive regulations for liner systems present in Subtitle D of the Resource and Conservation Recovery Act (RCRA). To provide uninterrupted service at the landfill, design and construction proceeded concurrently with regulatory approval.

Derian, L.; Gharios, K.M. (Los Angeles Bureau of Sanitation, CA (United States). Solid Waste Management Div.); Kavazanjian, E. Jr.; Snow, M.S. (GeoSyntec Consultants, Huntington Beach, CA (United States))

1993-12-01

319

Noble gas isotopic composition as a key reference parameter in a planetary atmospheric evolution model  

NASA Astrophysics Data System (ADS)

The isotopic composition of noble gases is a key reference parameter in discussing the evolution of planetary atmospheres. Currently, two widely occurring noble gas components are identified in the early solar system, one is the Solar Wind noble gas (SW-noble gas, hereafter) and another is the Q-noble gas in unaltered meteorites: both noble gases are characterized by their ubiquitous occurrence and high isotopic homogeneity. Since the SW-noble gas is directly ejected from the Sun, it has been assumed to be a good proxy of the average noble gas isotopic composition in the Sun, namely the solar noble gas. The systematic enrichment of the heavier isotopes in the Q-noble gas relative to the SW-noble gas is then commonly attributed to its isotopic fractionation from the SW-noble gas. However, the isotopic compositions of the SW-noble gas either implanted on lunar soils or trapped by artificial targets show considerable isotopic variation depending on the velocity of the Solar Wind. Therefore, it is important to examine how closely the SW-noble gas represents the indigenous solar noble gas component or the mean isotopic composition of noble gases of the Sun. Here we show that the isotopic composition of the SW-noble gas is substantially fractionated relative to the solar value, and therefore should not be used as a reference parameter. We further suggest that the post D-burning Q-noble gas (see below) is the better proxy of the solar noble gas, and this should be used as a reference of the Solar noble gas isotopic composition in discussing the planetary atmospheric evolution. The most distinct difference between the Q- and the SW-noble gas is apparent in a 3He/4He isotopic ratio: 4.64e-4 in Q-He [1], but 1.23e-4 in SW-He[2]. The difference is attributed to the conversion of deuteron (D) to 3He in the Sun, namely the D-burning [3], due to high temperature during the pre-main sequence stage of the Sun. With the use of recent data on D/H ratios from helio-seismology [4] and spectroscopic observation of the inter-stellar cloud [5], we estimated that the 3He/4He ratio in the post D-burning He in the Sun is 3.98e-4. The latter value is considerably smaller than the recent estimate of the SW-He ratio by the GENESIS mission of 3He/4He = 4.64e-4 [2]. We conclude that this difference is due to isotopic fractionation during the ejection of the Solar Wind from the solar atmosphere. The further interesting implication of this conclusion is that the marked difference in 3He/4He between the SW- and Q-noble gases can be used as an unique chronological marker in the planetary atmospheric evolution. [1] Busemann H. et al., Meteoritics & Planetary Science, 35, 949-973, 2000. [2] Heber V. et al. Geochimica Cosmochimica Acta, 73, 7414-7432, 2009. [3] Geiss J. and Reeve H. Astronomy Astrophysics, 18, 126-132, 1972. [4] Basu S. and Antia H.M. Astrophysical J. , 606:L85-L88, 2004. [5] Linsky J.L. et al. Astrophysical J., 647:1106-1124, 2006.

Ozima, M.

2010-12-01

320

Transport models for leachates from landfills  

NASA Astrophysics Data System (ADS)

During the last ten years, transport models to describe the solute migration in the subsurface were more and more developed. The simulation of solute transport can include the main processes influencing the amount of spreading, as advection, dispersion/diffusion, sorption and degradation. To use a mathematical model with confidence, it is important to have an insight into the assumptions und limitations describing the movement of solutes. These restrictions depend on the type of hydrogeology, on the type of solution and on important processes influencing the migration. Generally, the best validation of simulation and field measurements is available for the advective flow in porous media. Strong differences are to state for simulations with a high dispersive migration of solutes. This is given for cases with a very heterogeneous aquifer and high contrasts in the composition of the aqueous solution. A proper simulation of sorption and degradation is possible for a simplification of the natural conditions only. To model the transport of leachates from a landfill, a better understanding of sorption and degradation processes is necessary. Geochemical models can provide important informations. Because of the high complexity of the aqueous solution leaching from a landfill, assistant laboratory and field studies are necessary to deliver the basics for the geochemical approach. The article gives an overview on the limitations and restrictions using a transport model to simulate the migration of leachates.

Btow, E.; Lhr, H.-P.

321

MEASUREMENT OF PERSISTENT ORGANIC POLLUTANTS IN LANDFILL  

E-print Network

MEASUREMENT OF PERSISTENT ORGANIC POLLUTANTS IN LANDFILL LEACHATES I. ZDANEVITCH*, O. BOUR*, S, 22 rue Pasteur, F-22680 Etables sur mer, France SUMMARY: leachates from two landfills which receive. INTRODUCTION Leachates from two French landfills which receive biologically stabilized municipal solid waste

Paris-Sud XI, Université de

322

APPROACH FOR ESTIMATING GLOBAL LANDFILL METHANE EMISSIONS  

EPA Science Inventory

The report is an overview of available country-specific data and modeling approaches for estimating global landfill methane. Current estimates of global landfill methane indicate that landfills account for between 4 and 15% of the global methane budget. The report describes an ap...

323

Natural gas constituent and carbon isotopic composition in petroliferous basins, China  

NASA Astrophysics Data System (ADS)

There are abundant gas resources in petroliferous basins of China. Large to midsize gas fields are found in Eastern, central and Western of China. However, origin, constituents and isotopic composition of natural gas in different gas fields are varied distinctly, and some present strong chemical secondary alteration and show variation both in age and space. Based on the systematic analysis of constituents and carbon isotope of a large number of gas samples, combined with the geological characteristics, this paper classifies the origins of the gases, explores the gas isotope characteristics and evolutionary regulation with the variation time and space, and further discusses the distinctive geochemistry of the gases in China. These gases are dominated by dry gas, its methane carbon isotope values range from -10 to -70, ethane from -16 to -52, propane from -13 to -43, and butane from -18 to -34. The carbon isotopes of most gases show the characteristics of humic-derived gas and crude oil cracked gas. In addition, large primary biogenic gas fields have been discovered in the Qaidam basin; inorganic-derived alkane gases have been discovered in deep of the Songliao Basin. Half of these gas fields are characterized by the alkane carbon isotope reversal in different degrees. Research indicates there are several reasons can result in carbon isotope reversal. Firstly, gas charge of different genetic types or different source in one gas reservoir may cause carbon isotope reversal. Besides, high-over mature evolution of gas can also lead to the carbon isotopic reversal of alkanes. Thirdly, secondary alteration of hydrocarbons may also result in abnormal distribution of carbon isotope, isotope transforms to unusual light and heavy.

Zhu, Guangyou; Wang, Zhengjun; Dai, Jinxing; Su, Jing

2014-02-01

324

Venus lower atmospheric composition - Analysis by gas chromatography  

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

325

Determination of cellular fatty acid compositions of various yeasts by gas-liquid chromatography.  

PubMed Central

The cellular fatty acid composition of 51 cultures of various species of yeasts was determined by gas-liquid chromatography. Analysis was done with a fused-silica gas-liquid chromatography capillary column, with resolution of all components including mono-, di-, and tri-unsaturated 18-carbon acids. The cultures were placed into one of four distinct gas-liquid chromatography groups on the basis of large quantitative differences in fatty acids. Group I contained only Saccharomyces species and group II only Torulopsis glabrata. Most Candida species were placed into group III, and group IV contained only basidiomycetous yeasts. PMID:7161374

Moss, C W; Shinoda, T; Samuels, J W

1982-01-01

326

Estimating water content in an active landfill with the aid of GPR.  

PubMed

Landfill gas (LFG) receives a great deal of attention due to both negative and positive environmental impacts, global warming and a green energy source, respectively. However, predicting the quantity of LFG generated at a given landfill, whether active or closed is difficult due to the heterogeneities present in waste, and the lack of accurate in situ waste parameters like water content. Accordingly, ground penetrating radar (GPR) was evaluated as a tool for estimating in situ water content. Due to the large degree of subsurface heterogeneity and the electrically conductive clay cap covering landfills, both of which affect the transmission of the electromagnetic pulses, there is much scepticism concerning the use of GPR to quantify in situ water content within a municipal landfill. Two landfills were studied. The first landfill was used to develop the measurement protocols, while the second landfill provided a means of confirming these protocols. GPR measurements were initially completed using the surface GPR approach, but the lack of success led to the use of borehole (BH) GPR. Both zero offset profiling (ZOP) and multiple offset gathers (MOG) modes were tried, with the results indicating that BH GPR using the ZOP mode is the most simple and efficient method to measure in situ water content. The best results were obtained at a separation distance of 2m, where higher the water content, smaller the effective separation distance. However, an increase in water content did appear to increase the accuracy of the GPR measurements. For the effective separation distance of 2m at both landfills, the difference between GPR and lab measured water contents were reasonable at 33.9% for the drier landfill and 18.1% for the wetter landfill. Infiltration experiments also showed the potential to measure small increases in water content. PMID:23800648

Yochim, April; Zytner, Richard G; McBean, Edward A; Endres, Anthony L

2013-10-01

327

EFFECTS OF NATURAL-GAS COMPOSITION ON IGNITION DELAY UNDER DIESELCONDITIONS  

Microsoft Academic Search

Effects of variations in natural gas composition on the autoignition\\u000d\\u000a\\u0009of natural gas under direct-injection (DI) diesel engine conditions\\u000d\\u000a\\u0009were studied experimentally in a constant-volume combustion vessel\\u000d\\u000a\\u0009and computationally using a chemical kinetic model. Four fuel blends\\u000d\\u000a\\u0009were investigated: pure methane, a capacity-weighted mean natural\\u000d\\u000a\\u0009gas, a high-ethane-content natural gas, and a natural gas with added\\u000d\\u000a\\u0009propane typical of peak

J. D. Naber; D. L. Siebers; SS DIJULIO; C. K. Westbrook

1994-01-01

328

Gas Composition and Oxygen Supply in the Root Environment of Substrates in Closed Hydroponic Systems  

E-print Network

or 3 heights. Dissolved oxygen was determined with a membrane covered galvanic sensor, in the air299 Gas Composition and Oxygen Supply in the Root Environment of Substrates in Closed Hydroponic USA Germany Keywords: carbon dioxide, Dendranthema grandiflorum, dissolved oxygen, ethylene, substrate

Lieth, J. Heinrich

329

Compositional simulation and performance analysis of the Prudhoe Bay miscible gas project  

SciTech Connect

This paper reports that a pseudocomponent method was developed to use fully compositional reservoir simulation results in the interpretation of separator gas samples. The interpretation provided insight into actual EOR performance by quantifying solvent breakthrough and production rates. Field examples of various reservoir mechanisms affecting the efficiency of Prudhoe Bay EOR are examined.

McGuire, P.L.; Moritz, A.L. Jr. (Arco Alaska Inc. (United States))

1992-08-01

330

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

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

331

Finding the composition of gas mixtures by a phthalocyanine-coated QCM sensor array and an artificial neural network  

Microsoft Academic Search

This paper presents a system, which is made of an array of eight phthalocyanine-coated QCM sensors and an ANN to find the corresponding composition of a gas mixture. The digital data collected from the sensor responses were preprocessed by a sliding window algorithm, and then used to train a three layer ANN to determine the gas compositions. The system is

A. zmen; F. Tekce; M. A. Ebeo?lu; C. Ta?alt?n; Z. Z. ztrk

2006-01-01

332

Comparison of slope stability in two Brazilian municipal landfills.  

PubMed

The implementation of landfill gas to energy (LFGTE) projects has greatly assisted in reducing the greenhouse gases and air pollutants, leading to an improved local air quality and reduced health risks. The majority of cities in developing countries still dispose of their municipal waste in uncontrolled 'open dumps.' Municipal solid waste landfill construction practices and operating procedures in these countries pose a challenge to implementation of LFGTE projects because of concern about damage to the gas collection infrastructure (horizontal headers and vertical wells) caused by minor, relatively shallow slumps and slides within the waste mass. While major slope failures can and have occurred, such failures in most cases have been shown to involve contributory factors or triggers such as high pore pressures, weak foundation soil or failure along weak geosynthetic interfaces. Many researchers who have studied waste mechanics propose that the shear strength of municipal waste is sufficient such that major deep-seated catastrophic failures under most circumstances require such contributory factors. Obviously, evaluation of such potential major failures requires expert analysis by geotechnical specialists with detailed site-specific information regarding foundation soils, interface shearing resistances and pore pressures both within the waste and in clayey barrier layers or foundation soils. The objective of this paper is to evaluate the potential use of very simple stability analyses which can be used to study the potential for slumps and slides within the waste mass and which may represent a significant constraint on construction and development of the landfill, on reclamation and closure and on the feasibility of a LFGTE project. The stability analyses rely on site-specific but simple estimates of the unit weight of waste and the pore pressure conditions and use "generic" published shear strength envelopes for municipal waste. Application of the slope stability analysis method is presented in a case study of two Brazilian landfill sites; the Cruz das Almas Landfill in Maceio and the Muribeca Landfill in Recife. The Muribeca site has never recorded a slope failure and is much larger and better-maintained when compared to the Maceio site at which numerous minor slumps and slides have been observed. Conventional limit-equilibrium analysis was used to calculate factors of safety for stability of the landfill side slopes. Results indicate that the Muribeca site is more stable with computed factors of safety values in the range 1.6-2.4 compared with computed values ranging from 0.9 to 1.4 for the Maceio site at which slope failures have been known to occur. The results suggest that this approach may be useful as a screening-level tool when considering the feasibility of implementing LFGTE projects. PMID:17897819

Gharabaghi, B; Singh, M K; Inkratas, C; Fleming, I R; McBean, E

2008-01-01

333

Eukaryotic diversity in an anaerobic aquifer polluted with landfill leachate  

Microsoft Academic Search

Eukaryotes may influence pollutant degradation processes in groundwater ecosystems by activities such as predation on bacteria and recycling of nutrients. Culture-independent community profiling and phylogenetic analysis of 18S rRNA gene fragments, as well as culturing, were employed to obtain insight into the sediment- associated eukaryotic community composition in an anaerobic sandy aquifer polluted with landfill leachate (Ban- isveld, The Netherlands).

Traian Brad; Martin Braster; Breukelen van B. M; Straalen van N. M; Wilfred F. M. Roling

2008-01-01

334

Economic aspects of the rehabilitation of the Hiriya landfill  

SciTech Connect

The Hiriya landfill, Israel's largest, operated from 1952 to 1998. The landfill, located in the heart of the Dan Region, developed over the years into a major landscape nuisance and environmental hazard. In 1998, the Israeli government decided to close the landfill, and in 2001 rehabilitation activities began at the site, including site investigations, engineering and scientific evaluations, and end-use planning. The purpose of the present research is to perform a cost-benefit analysis of engineering and architectural-landscape rehabilitation projects considered for the site. An engineering rehabilitation project is required for the reduction of environmental impacts such as greenhouse gas emissions, slope instability and leachate formation. An architectural-landscape rehabilitation project would consider improvements to the site to make it suitable for future end uses such as a public park. The findings reveal that reclamation is worthwhile only in the case of architectural-landscape rehabilitation of the landfill, converting it into a public park. Engineering rehabilitation alone was found to be unjustified, but is essential to enable the development of a public park.

Ayalon, O. [Department of Natural Resources and Environmental Management and NRERC, Haifa University, 32000 Haifa (Israel)]. E-mail: agofira@tx.technion.ac.il; Becker, N. [Department of Natural Resources and Environmental Management and NRERC, Haifa University, 32000 Haifa (Israel); Department of Economics and Management, Tel Hai College and NRERC, University of Haifa, Haifa (Israel); Shani, E. [Dan Region Association of Towns, Sanitation and Waste Disposal (Israel)

2006-07-01

335

Temporal and Spatial Pore Water Pressure Distribution Surrounding a Vertical Landfill Leachate Recirculation Well  

PubMed Central

Addition of liquids into landfilled waste can result in an increase in pore water pressure, and this in turn may increase concerns with respect to geotechnical stability of the landfilled waste mass. While the impact of vertical well leachate recirculation on landfill pore water pressures has been mathematically modeled, measurements of these systems in operating landfills have not been reported. Pressure readings from vibrating wire piezometers placed in the waste surrounding a liquids addition well at a full-scale operating landfill in Florida were recorded over a 2-year period. Prior to the addition of liquids, measured pore pressures were found to increase with landfill depth, an indication of gas pressure increase and decreasing waste permeability with depth. When liquid addition commenced, piezometers located closer to either the leachate injection well or the landfill surface responded more rapidly to leachate addition relative to those far from the well and those at deeper locations. After liquid addition stopped, measured pore pressures did not immediately drop, but slowly decreased with time. Despite the large pressures present at the bottom of the liquid addition well, much smaller pressures were measured in the surrounding waste. The spatial variation of the pressures recorded in this study suggests that waste permeability is anisotropic and decreases with depth. PMID:21655145

Kadambala, Ravi; Townsend, Timothy G.; Jain, Pradeep; Singh, Karamjit

2011-01-01

336

Temporal and spatial pore water pressure distribution surrounding a vertical landfill leachate recirculation well.  

PubMed

Addition of liquids into landfilled waste can result in an increase in pore water pressure, and this in turn may increase concerns with respect to geotechnical stability of the landfilled waste mass. While the impact of vertical well leachate recirculation on landfill pore water pressures has been mathematically modeled, measurements of these systems in operating landfills have not been reported. Pressure readings from vibrating wire piezometers placed in the waste surrounding a liquids addition well at a full-scale operating landfill in Florida were recorded over a 2-year period. Prior to the addition of liquids, measured pore pressures were found to increase with landfill depth, an indication of gas pressure increase and decreasing waste permeability with depth. When liquid addition commenced, piezometers located closer to either the leachate injection well or the landfill surface responded more rapidly to leachate addition relative to those far from the well and those at deeper locations. After liquid addition stopped, measured pore pressures did not immediately drop, but slowly decreased with time. Despite the large pressures present at the bottom of the liquid addition well, much smaller pressures were measured in the surrounding waste. The spatial variation of the pressures recorded in this study suggests that waste permeability is anisotropic and decreases with depth. PMID:21655145

Kadambala, Ravi; Townsend, Timothy G; Jain, Pradeep; Singh, Karamjit

2011-05-01

337

A performance-based system for the long-term management of municipal waste landfills.  

PubMed

Landfills have been the dominant alternative for disposal of solid waste and there are tens of thousands of closed landfills throughout the world that require a long-term management strategy. In contrast to approaches based on time or target values, this paper describes a performance-based methodology for evaluation of post-closure care (PCC). Using the methodology, critical components of PCC at a landfill, including leachate and gas management, groundwater monitoring and cover integrity, are considered to determine whether a landfill meets defined conditions for functional stability and can transition from regulated PCC to a post-regulatory custodial care program representing de minimus care activities only. The methodology is predicated on understanding the biological, chemical, and physical behavior of a landfill and the presence of sufficient data to verify expected trends in landfill behavior. If an evaluation suggests that a change can be made to PCC, the landfill owner must perform confirmation monitoring and then surveillance monitoring at a decreasing frequency to verify that the change is protective of human health and the environment. A hypothetical case study showed that using the methodology to evaluate site-specific PCC requirements could result in increased environmental protection at comparable cost by spending available funds where they are most needed. PMID:21186115

Morris, Jeremy W F; Barlaz, Morton A

2011-04-01

338

N 2O emissions at municipal solid waste landfill sites: Effects of CH 4 emissions and cover soil  

NASA Astrophysics Data System (ADS)

Municipal solid waste landfills are the significant anthropogenic sources of N 2O due to the cooxidation of ammonia by methane-oxidizing bacteria in cover soils. Such bacteria could be developed through CH 4 fumigation, as evidenced by both laboratory incubation and field measurement. During a 10-day incubation with leachate addition, the average N 2O fluxes in the soil samples, collected from the three selected landfill covers, were multiplied by 1.75 ( p < 0.01), 3.56 ( p < 0.01), and 2.12 ( p < 0.01) from the soil samples preincubated with 5% CH 4 for three months when compared with the control, respectively. Among the three selected landfill sites, N 2O fluxes in two landfill sites were significantly correlated with the variations of the CH 4 emissions without landfill gas recovery ( p < 0.001). N 2O fluxes were also elevated by the increase of the CH 4 emissions with landfill gas recovery in another landfill site ( p > 0.05). The annual average N 2O flux was 176 566 ?g N 2O-N m -2 h -1 ( p < 0.01) from sandy soil-covered landfill site, which was 72% ( p < 0.05) and 173% ( p < 0.01) lower than the other two clay soil covered landfill sites, respectively. The magnitude order of N 2O emissions in three landfill sites was also coincident by the results of laboratory incubation, suggesting the sandy soil cover could mitigate landfill N 2O emissions.

Zhang, Houhu; He, Pinjing; Shao, Liming

339

Methane emissions from MSW landfill with sandy soil covers under leachate recirculation and subsurface irrigation  

NASA Astrophysics Data System (ADS)

CH 4 emissions and leachate disposal are recognized as the two major concerns in municipal solid waste (MSW) landfills. Recently, leachate recirculation was attempted to accelerate land-filled waste biodegradation and thus enhanced landfill gas generation. Leachate irrigation was also conducted for volume reduction effectively. Nevertheless, the impacts of leachate recirculation and irrigation on landfill CH 4 emissions have not been previously reported. A field investigation of landfill CH 4 emissions was conducted on selected sandy soil cover with leachate recirculation and subsurface irrigation based on whole year around measurement. The average CH 4 fluxes were 311903, 207516, and 5651460 CH 4 m -2 h -1 from site A without leachate recirculation and subsurface irrigation, lift B2 with leachate subsurface irrigation, and lift B1 with both leachate recirculation and subsurface irrigation, respectively. Both gas recovery and cover soil oxidation minimized CH 4 emissions efficiently, while the later might be more pronounced when the location was more than 5 m away from gas recovery well. After covered by additional clay soil layer, CH 4 fluxes dropped by approximately 35 times in the following three seasons compared to the previous three seasons in lift B2. The diurnal peaks of CH 4 fluxes occurred mostly followed with air or soil temperature in the daytimes. The measured CH 4 fluxes were much lower than those of documented data from the landfills, indicating that the influences of leachate recirculation and subsurface irrigation on landfill CH 4 emissions might be minimized with the help of a well-designed sandy soil cover. Landfill cover composed of two soil layers (clay soil underneath and sandy soil above) is suggested as a low-cost and effective alternative to minimize CH 4 emissions.

Zhang, Houhu; He, Pinjing; Shao, Liming

340

Helium gas permeability of SiC\\/SiC composite used for in-vessel components of nuclear fusion reactor  

Microsoft Academic Search

SiC\\/SiC composite is a candidate material of blanket in fusion reactors since silicon carbide is a low activation material and the temperature of helium coolant can be taken high, 1100K. Helium gas permeability of SiC\\/SiC composite, however, has been little measured so far for this purpose. For SiC\\/SiC composites made by several methods, the helium gas permeability was measured using

T. Hino; E. Hayashishita; Y. Yamauchi; M. Hashiba; Y. Hirohata; A. Kohyama

2005-01-01

341

Using gas-phase nitric acid as an indicator of PSC composition  

NASA Astrophysics Data System (ADS)

The composition of polar stratospheric cloud particles is investigated using data from several remote sensing instruments: gas-phase HNO3 measured by the Airborne Submillimeter Radiometer (ASUR), temperature measured by the Airborne Raman Ozone, Temperature and Aerosol Lidar (AROTEL), and aerosol backscatter wavelength dependence and depolarization measured by the UV Differential Absorption Lidar (DIAL). All three instruments have been operated onboard the NASA DC-8 during the SOLVE winter 1999/2000. A simple thermodynamical model is used to calculate the gas-phase amount of HNO3 in the presence of polar stratospheric clouds (PSCs) along the flight track of the DC-8 for one flight into the polar vortex on 7 December 1999. Three types of PSCs are considered in the model: nitric acid trihydrate (NAT), nitric acid dihydrate (NAD), and supercooled ternary solutions (STS). The comparison of the modeled and measured gas-phase HNO3 in the presence of PSCs shows a very good agreement if a NAT composition of the particles is assumed. However, sensitivity studies show that while the PSCs observed on this flight are not in agreement with a STS composition, the model is very sensitive to temperature, and a NAD composition of the PSC cannot be ruled out.

von Knig, Miriam; Bremer, Holger; Kleinbhl, Armin; Kllmann, Harry; Knzi, Klaus F.; Goede, Albert P. H.; Browell, Edward V.; Grant, William B.; Burris, John F.; McGee, Thomas J.; Twigg, Laurence

2002-08-01

342

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

SciTech Connect

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

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

2006-05-03

343

Composition of Titan's lower atmosphere and simple surface volatiles as measured by the CassiniHuygens probe gas  

E-print Network

Huygens probe gas chromatograph mass spectrometer experiment H. B. Niemann,1 S. K. Atreya,2 J. E. Demick,3 D] The CassiniHuygens probe gas chromatograph mass spectrometer (GCMS) determined the composition of the Titan as measured by the CassiniHuygens probe gas chromatograph mass spectrometer experiment, J. Geophys. Res., 115

Atreya, Sushil

344

Influence of gas composition on wafer temperature in a tungsten chemical vapor deposition reactor: Experimental measurements, model  

E-print Network

Influence of gas composition on wafer temperature in a tungsten chemical vapor deposition reactor and experimental observations both demonstrated that the gas velocity field had little influence on the observed wafer and predicted gas temperatures. � 2001 American Vacuum Society. DOI: 10.1116/1.1333076 I

Rubloff, Gary W.

345

Method of making a continuous ceramic fiber composite hot gas filter  

DOEpatents

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

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

1999-01-01

346

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

NASA Astrophysics Data System (ADS)

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

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

347

Landfill reduction experience in The Netherlands.  

PubMed

Modern waste legislation aims at resource efficiency and landfill reduction. This paper analyses more than 20years of landfill reduction in the Netherlands. The combination of landfill regulations, landfill tax and landfill bans resulted in the desired landfill reduction, but also had negative effects. A fierce competition developed over the remaining waste to be landfilled. In 2013 the Dutch landfill industry generated 40 million of annual revenue, had 58 million annual costs and therefore incurred an annual loss of 18 million. It is not an attractive option to prematurely end business. There is a risk that Dutch landfill operators will not be able to fulfil the financial obligations for closure and aftercare. Contrary to the polluter pays principle the burden may end up with society. EU regulations prohibiting export of waste for disposal are in place. Strong differentials in landfill tax rate between nations have nevertheless resulted in transboundary shipment of waste and in non-compliance with the self-sufficiency and proximity principles. During the transformation from a disposal society to a recycling society, it is important to carefully plan required capacity and to guide the reorganisation of the landfill sector. At some point, it is no longer profitable to provide landfill services. It may be necessary for public organisations or the state to take responsibility for the continued operation of a 'safety net' in waste management. Regulations have created a financial incentive to pass on the burden of monitoring and controlling the impact of waste to future generations. To prevent this, it is necessary to revise regulations on aftercare and create incentives to actively stabilise landfills. PMID:24999096

Scharff, Heijo

2014-11-01

348

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

PubMed

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

Dai, Ning; Mitch, William A

2014-07-01

349

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

NASA Technical Reports Server (NTRS)

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

Darolia, R.

1979-01-01

350

Airborne emissions of mercury from municipal solid waste. II: potential losses of airborne mercury before landfill.  

PubMed

Waste distribution and compaction at the working face of municipal waste landfills releases mercury vapor (Hg(o)) to the atmosphere, as does the flaring of landfill gas. Waste storage and processing before its addition to the landfill also has the potential to release Hg(o) to the air if it is initially present or formed by chemical reduction of Hg(II) to Hg(o) within collected waste. We measured the release of Hg vapor to the atmosphere during dumpster and transfer station activities and waste storage before landfilling at a municipal landfill operation in central Florida. We also quantified the potential contribution of specific Hg-bearing wastes, including mercury (Hg) thermometers and fluorescent bulbs, and searched for primary Hg sources in sorted wastes at three different landfills. Surprisingly large fluxes were estimated for Hg losses at transfer facilities (approximately 100 mg/hr) and from dumpsters in the field (approximately 30 mg/hr for 1000 dumpsters), suggesting that Hg emissions occurring before landfilling may constitute a significant fraction of the total emission from the disposal/landfill cycle and a need for more measurements on these sources. Reducing conditions of landfill burial were obviously not needed to generate strong Hg(o) signals, indicating that much of the Hg was already present in a metallic (Hg(o)) form. Attempts to identify specific Hg sources in excavated and sorted waste indicated few readily identifiable sources; because of effective mixing and diffusion of Hg(o), the entire waste mass acts as a source. Broken fluorescent bulbs and thermometers in dumpsters emitted Hg(o) at 10 to >100 microg/hr and continued to act as near constant sources for several days. PMID:16111126

Southworth, George R; Lindberg, Steve E; Bogle, Mary Anna; Zhang, Hong; Kuiken, Todd; Price, Jack; Reinhart, Debra; Sfeir, Hala

2005-07-01

351

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

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

352

Modeling of H2S migration through landfill cover materials.  

PubMed

The emission of H2S from landfills in the United States is an emergent problem because measured concentrations within the waste mass and in ambient air have been observed at potentially unsafe levels for on-site workers and at levels that can cause a nuisance and potentially deleterious health impacts to surrounding communities. Though recent research has provided data on H2S concentrations that may be observed at landfills, facility operators and landfill engineers have limited predictive tools to anticipate and plan for potentially harmful H2S emissions. A one-dimensional gas migration model was developed to assist engineers and practitioners better evaluate and predict potential emission levels of H2S based on four factors: concentration of H2S below the landfill surface (C0), advection velocity (v), H2S effective diffusion coefficient (D), and H2S adsorption coefficient of landfill cover soil (?). Model simulations indicated that H2S migration into the atmosphere can be mitigated by reducing H2S diffusion and advection or using alternative cover soils with a high H2S adsorption coefficient. Laboratory column experiments were conducted to investigate the effects of the four parameters on H2S migration in cover soils and to calculate the adsorption coefficient of different cover materials. The model was validated by comparing results with laboratory column experiments. Based on the results, the laboratory column provides an effective way to estimate the H2S adsorption coefficient, which can then be incorporated into the developed model to predict the depth of cover soil required to reduce emitted H2S concentrations below a desired level. PMID:24316799

Xu, Qiyong; Powell, Jon; Jain, Pradeep; Townsend, Timothy

2014-01-15

353

Thermodynamic analysis of the gas phase composition over uranium-plutonium carbonitride irradiated with fast neutrons  

Microsoft Academic Search

A thermodynamic analysis of the gas phase composition over uranium-plutonium carbonitride U0.8Pu0.2(C0.5N0.5)0.995 irradiated with fast neutrons was carried out with respect to temperature and burnout. In the temperature range of 9002500\\u000a K, accumulation of fission products in fuel resulted in the formation of a multicomponent gas phase containing the following\\u000a basic elements and compounds: volatile (Cs, Sr, Ba, Se, Te,

G. S. Bulatov; K. N. Gedgovd; D. Yu. Lyubimov

2009-01-01

354

Plants scrub landfill leachate clean  

SciTech Connect

Leachate from the sanitary landfill in Barre, Mass., is collected in a series of holding lagoons. There, aquatic plants such as duckweed biodegrade and purify the wastewater. The plants saturate the leachate with oxygen, which speeds up aerobic oxidation by bacteria. The leachate is moved progressively through the series of lagoons, and the contents of the final lagoon are emptied into a trout pond. (3 photos)

Not Available

1980-09-01

355

Did state renewable portfolio standards induce technical change in methane mitigation in the U.S. landfill sector?  

NASA Astrophysics Data System (ADS)

Landfill gas (LFG) projects use the gas created from decomposing waste, which is approximately 49% methane, and substitute it for natural gas in engines, boilers, turbines, and other technologies to produce energy or heat. The projects are beneficial in terms of increased safety at the landfill, production of a cost-effective source of energy or heat, reduced odor, reduced air pollution emissions, and reduced greenhouse gas emissions. However, landfills sometimes face conflicting policy incentives. The theory of technical change shows that the diffusion of a technology or groups of technologies increases slowly in the beginning and then picks up speed as knowledge and better understanding of using the technology diffuses among potential users. Using duration analysis, data on energy prices, State and Federal policies related to landfill gas, renewable energy, and air pollution, as well as control data on landfill characteristics, I estimate the influence and direction of influence of renewable portfolio standards (RPS). The analysis found that RPS positively influences the diffusion of landfill gas technologies, encouraging landfills to consider electricity generation projects over direct sales of LFG to another facility. Energy price increases or increased revenues for a project are also critical. Barriers to diffusion include air emission permits in non-attainment areas and policies, such as net metering, which promote other renewables over LFG projects. Using the estimates from the diffusion equations, I analyze the potential influence of a Federal RPS as well as the potential interaction with a Federal, market based climate change policy, which will increase the revenue of a project through higher energy sale prices. My analysis shows that a market based climate change policy such as a cap-and-trade or carbon tax scheme would increase the number of landfill gas projects significantly more than a Federal RPS.

Delhotal, Katherine Casey

356

Seismic evaluation of municipal solid waste landfill  

SciTech Connect

With the promulgation of the Resource Conservation and Recovery (RCRA) Subtitle D, landfills situated within seismic impact zones must be evaluated for seismic hazards to demonstrate that the containment structures of the landfill can resist the maximum horizontal acceleration in lithified earth materials (bedrock) for the site. If a landfill is sited on saturated soils, it must also be evaluated for liquefaction and lateral spreading. In 1994, EMCON evaluated the seismic hazard for a landfill located along the Columbia River in southwestern Washington. The landfill was founded on dredge fill over natural alluvial deposits. Laboratory testing and state-of-the-art engineering analyses indicated that the sand unit below the landfill had a high potential for liquefaction. The seismic hazard evaluation for the site included a site-specific seismic response analysis, a liquefaction potential analysis, and seismic stability and deformation analysis. The seismic response analysis was conducted for nonliquefied, partially liquefied, and fully liquefied foundation soil conditions. Results are described.

Hovind, C.; Slyh, R. [EMCON, Portland, OR (United States)

1995-12-31

357

An integrated analytical framework for quantifying the LCOE of waste-to-energy facilities for a range of greenhouse gas emissions policy and technical factors  

SciTech Connect

This study presents a novel integrated method for considering the economics of waste-to-energy (WTE) facilities with priced greenhouse gas (GHG) emissions based upon technical and economic characteristics of the WTE facility, MSW stream, landfill alternative, and GHG emissions policy. The study demonstrates use of the formulation for six different policy scenarios and explores sensitivity of the results to ranges of certain technical parameters as found in existing literature. The study shows that details of the GHG emissions regulations have large impact on the levelized cost of energy (LCOE) of WTE and that GHG regulations can either increase or decrease the LCOE of WTE depending on policy choices regarding biogenic fractions from combusted waste and emissions from landfills. Important policy considerations are the fraction of the carbon emissions that are priced (i.e. all emissions versus only non-biogenic emissions), whether emissions credits are allowed due to reducing fugitive landfill gas emissions, whether biogenic carbon sequestration in landfills is credited against landfill emissions, and the effectiveness of the landfill gas recovery system where waste would otherwise have been buried. The default landfill gas recovery system effectiveness assumed by much of the industry yields GHG offsets that are very close to the direct non-biogenic GHG emissions from a WTE facility, meaning that small changes in the recovery effectiveness cause relatively larger changes in the emissions factor of the WTE facility. Finally, the economics of WTE are dependent on the MSW stream composition, with paper and wood being advantageous, metal and glass being disadvantageous, and plastics, food, and yard waste being either advantageous or disadvantageous depending upon the avoided tipping fee and the GHG emissions price.

Townsend, Aaron K., E-mail: aarontownsend@utexas.edu [Department of Mechanical Engineering, University of Texas at Austin, 1 University Station C2200, Austin, TX 78712 (United States); Webber, Michael E. [Department of Mechanical Engineering, University of Texas at Austin, 1 University Station C2200, Austin, TX 78712 (United States)

2012-07-15

358

An integrated analytical framework for quantifying the LCOE of waste-to-energy facilities for a range of greenhouse gas emissions policy and technical factors.  

PubMed

This study presents a novel integrated method for considering the economics of waste-to-energy (WTE) facilities with priced greenhouse gas (GHG) emissions based upon technical and economic characteristics of the WTE facility, MSW stream, landfill alternative, and GHG emissions policy. The study demonstrates use of the formulation for six different policy scenarios and explores sensitivity of the results to ranges of certain technical parameters as found in existing literature. The study shows that details of the GHG emissions regulations have large impact on the levelized cost of energy (LCOE) of WTE and that GHG regulations can either increase or decrease the LCOE of WTE depending on policy choices regarding biogenic fractions from combusted waste and emissions from landfills. Important policy considerations are the fraction of the carbon emissions that are priced (i.e. all emissions versus only non-biogenic emissions), whether emissions credits are allowed due to reducing fugitive landfill gas emissions, whether biogenic carbon sequestration in landfills is credited against landfill emissions, and the effectiveness of the landfill gas recovery system where waste would otherwise have been buried. The default landfill gas recovery system effectiveness assumed by much of the industry yields GHG offsets that are very close to the direct non-biogenic GHG emissions from a WTE facility, meaning that small changes in the recovery effectiveness cause relatively larger changes in the emissions factor of the WTE facility. Finally, the economics of WTE are dependent on the MSW stream composition, with paper and wood being advantageous, metal and glass being disadvantageous, and plastics, food, and yard waste being either advantageous or disadvantageous depending upon the avoided tipping fee and the GHG emissions price. PMID:22425189

Townsend, Aaron K; Webber, Michael E

2012-07-01

359

Inverse gas chromatographic and chemometric tools for determination of interactions between the components of polymeric composition  

Microsoft Academic Search

Compositions of polymers (polyethylene and polyuretane) and fillers (initial silica and silicas modified with: N-2-aminoethyl-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxy-silane, 3-merkaptopropyltrimethoxysilane, octyltriethoxysilane) were examined by inverse gas chromatography at 383K. Small amounts of the following test solutes were injected to achieve the infinite dilution conditions: pentane, hexane, heptane, octane, nonane, dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane.The retention times for these test solutes were determined

A. Voelkel; K. Milczewska; K. Hberger

2006-01-01

360

A neutral gas mass spectrometer to measure the chemical composition of the stratosphere  

Microsoft Academic Search

The Polar Balloon Atmospheric Composition Experiment (P-BACE) is a new generation of neutral gas mass spectrometer based on the time-of-flight principle. P-BACE is the scientific experiment on the Mars Environment Analog Platform (MEAP) flown successfully on a balloon mission in summer 2008. The MEAP mission was flown with a 334,000m3 helium balloon in the stratosphere on a semicircular trajectory from

D. Abplanalp; P. Wurz; L. Huber; I. Leya; E. Kopp; U. Rohner; M. Wieser; L. Kalla; S. Barabash

2009-01-01

361

Ceramic Matrix Composite Vane Subelement Testing in a Gas Turbine Environment  

NASA Technical Reports Server (NTRS)

Vane subelements were fabricated from a silicon carbide fiber reinforced silicon carbide matrix (SiC/SiC) composite and were coated with an environmental barrier coating (EBC). A test configuration for the vanes in a gas turbine environment was designed and fabricated. Prior to testing, finite element analyses were performed to predict the temperatures and stress conditions present in vane during rig testing. This paper discusses the test configuration, the finite element analysis predictions, and results of the vane testing.

Verrilli, Michael; Calomino, Anthony; Robinson, R. Craig; Thomas, David J.

2004-01-01

362

Equilibrium and compositional properties of CO2 - N2 gas hydrates investigated by Raman spectroscopy  

NASA Astrophysics Data System (ADS)

The global greenhouse effect of CO2 has attracted increased attention as a worldwide problem. CO2 capture and sequestration (CCS) for industry is a great challenge that is susceptible to reduce carbon emission. Exhausting gases from industry contains CO2, N2, CH4, O2 and are generally localized: steelmaking plants, gas or coal power plants, chemical plants The quantities to be treated are very important, in the range of several cubic meters per second. In post combustion capture, CO2 concentration is generally low, typically 5-10% for power plants, but it can be higher: up to 40% in steelmaking plants, or also in some cases of natural gas production. Different strategies and technologies of capture need to be developed to decrease the cost of the process, in respect to the specific compositions and operative conditions, especially pressure. Hydrate technology could be an alternative that needs further development. The work that is presented here is a preliminary research to evaluate the equilibrium and compositional properties of gas mixtures of CO2-N2 for potential of CO2 capture using a hydrate technology. A knew experimental set-up has been developed to produce and analyze gas hydrates in-situ by Raman spectroscopy. A high pressure and low temperature optical reactor has been built to investigate thermodynamic equilibrium properties of gas hydrates. The hydrates are crystallized from a mixture of water and gases (CO2 and N2). The characteristic spectral signature of CO2 and N2 trapped in the hydrate structure can be easily distinguished from that in the gaseous phase above the so-formed hydrates. The hydrate phase composition is evaluated by Raman and compared with that obtained from thermodynamic models of hydrate phase equilibrium prediction.

Chazallon, Bertrand

2010-05-01

363

Design and Modeling of a Selective Composite n/p Gas Sensor  

NASA Astrophysics Data System (ADS)

Mixtures of anatase and rutile TiO2 can provide an n-type/p-type composite with attractive gas sensing properties for high temperature industrial environments. We have developed the Polychromatic Percolation Model (PPM) to facilitate the development of a gas sensor selective to carbon monoxide and methane. We find that the sensor response (n-type or p-type) to a reducing gas follows the least resistive intergranular path, and depends on the n-type/p-type composition, the sintered density, and the grain size ratio between the n- and p- grains. Our calculations are confirmed by both SEM micrographs of the composite microstructure, and sensing data.* The PPM is also able to explain CO selectivity in a 75/25 mixture of anatase/rutile. We will discuss recent extensions of the PPM, which offer designs for control over the selectivity using previous methods** for adjusting single-phase sensor responses. * N. Savage, B. Chwieroth, et al, Sensors and Actuators B (2001). ** B.Chwieroth, B.R. Patton, Y. Wang, J. Electroceramics (2001).

Chwieroth, Brian; Patton, Bruce R.; Savage, Nancy; Dutta, Prabir K.

2001-03-01

364

High temperature hydrogen sulfide adsorption on activated carbon - I. Effects of gas composition and metal addition  

USGS Publications Warehouse

Various types of activated carbon sorbents were evaluated for their ability to remove H2S from a simulated coal gas stream at a temperature of 550 ??C. The ability of activated carbon to remove H2S at elevated temperature was examined as a function of carbon surface chemistry (oxidation, thermal desorption, and metal addition), and gas composition. A sorbent prepared by steam activation, HNO3 oxidation and impregnated with Zn, and tested in a gas stream containing 0.5% H2S, 50% CO2 and 49.5% N2, had the greatest H2S adsorption capacity. Addition of H2, CO, and H2O to the inlet gas stream reduced H2S breakthrough time and H2S adsorption capacity. A Zn impregnated activated carbon, when tested using a simulated coal gas containing 0.5% H2S, 49.5% N2, 13% H2, 8.5% H2O, 21% CO, and 7.5% CO2, had a breakthrough time of 75 min, which was less than 25 percent of the length of breakthrough for screening experiments performed with a simplified gas mixture of 0.5% H2S, 50% CO2, and 49.5% N2.

Cal, M. P.; Strickler, B. W.; Lizzio, A. A.

2000-01-01

365

Investigations of natural attenuation in groundwater near a landfill and implications for landfill post-closure  

E-print Network

. While isotopic data suggest a signature of the landfill leachate in the groundwater in the vicinity of the biogeochemistry of landfill leachate plumes, Christensen et al. (2001) note that "Heavy metals do not seem1 Investigations of natural attenuation in groundwater near a landfill and implications

Paris-Sud XI, Université de

366

Landfill Disposal of CCA-Treated Wood with Construction and  

E-print Network

and chromium were significantly higher in the experimental simulated landfill leachate compared to the control simulated landfill leachate (R ) 0.05, p Landfill Disposal of CCA-Treated Wood with Construction and Demolition (C&D) Debris: Arsenic

Florida, University of

367

Aluminum Reactions and Problems in Municipal Solid Waste Landfills  

E-print Network

problematic for landfill operations by generating undesirable heat, liquid leachate, and gases reactions. Another source of water in a MSW landfill is leachate recirculation, which is not recommended: Solid wastes; Aluminum; Chemicals; Waste disposal; Landfills. Author keywords: Solid waste; Leachate

368

Mixed Waste Landfill Integrated Demonstration; Technology summary  

SciTech Connect

The mission of the Mixed Waste Landfill Integrated Demonstration (MWLID) is to demonstrate, in contaminated sites, new technologies for clean-up of chemical and mixed waste landfills that are representative of many sites throughout the DOE Complex and the nation. When implemented, these new technologies promise to characterize and remediate the contaminated landfill sites across the country that resulted from past waste disposal practices. Characterization and remediation technologies are aimed at making clean-up less expensive, safer, and more effective than current techniques. This will be done by emphasizing in-situ technologies. Most important, MWLID`s success will be shared with other Federal, state, and local governments, and private companies that face the important task of waste site remediation. MWLID will demonstrate technologies at two existing landfills. Sandia National Laboratories` Chemical Waste Landfill received hazardous (chemical) waste from the Laboratory from 1962 to 1985, and the Mixed-Waste Landfill received hazardous and radioactive wastes (mixed wastes) over a twenty-nine year period (1959-1988) from various Sandia nuclear research programs. Both landfills are now closed. Originally, however, the sites were selected because of Albuquerque`s and climate and the thick layer of alluvial deposits that overlay groundwater approximately 480 feet below the landfills. This thick layer of ``dry`` soils, gravel, and clays promised to be a natural barrier between the landfills and groundwater.

NONE

1994-02-01

369

Bioreactor Landfill Research and Demonstration Project Northern Oaks Landfill, Harrison, MI  

SciTech Connect

A bioreactor landfill cell with 1.2-acre footprint was constructed, filled, operated, and monitored at Northern Oaks Recycling and Disposal Facility (NORDF) at Harrison, MI. With a filled volume of 74,239 cubic yards, the cell contained approximately 35,317 tons of municipal solid waste (MSW) and 20,777 tons of cover soil. It was laid on the slope of an existing cell but separated by a geosynthetic membrane liner. After the cell reached a design height of 60 feet, it was covered with a geosynthetic membrane cap. A three-dimensional monitoring system to collect data at 48 different locations was designed and installed during the construction phase of the bioreactor cell. Each location had a cluster of monitoring devices consisting of a probe to monitor moisture and temperature, a leachate collection basin, and a gas sampling port. An increase in moisture content of the MSW in the bioreactor cell was achieved by pumping leachate collected on-site from various other cells, as well as recirculation of leachate from the bioreactor landfill cell itself. Three types of leachate injection systems were evaluated in this bioreactor cell for their efficacy to distribute pumped leachate uniformly: a leachate injection pipe buried in a 6-ft wide horizontal stone mound, a 15-ft wide geocomposite drainage layer, and a 60-ft wide geocomposite drainage layer. All leachate injection systems were installed on top of the compacted waste surface. The distribution of water and resulting MSW moisture content throughout the bioreactor cell was found to be similar for the three designs. Water coming into and leaving the cell (leachate pumped in, precipitation, snow, evaporation, and collected leachate) was monitored in order to carry out a water balance. Using a leachate injection rate of 26 30 gal/yard3, the average moisture content increased from 25% to 35% (wet based) over the period of this study. One of the key aspects of this bioreactor landfill study was to evaluate bioreactor start up and performance in locations with colder climate. For lifts filled during the summer months, methane generation started within three months after completion of the lift. For lifts filled in winter months, very little methane production occurred even eight months after filling. The temperature data indicated that subzero or slightly above zero (oC) temperatures persisted for unusually long periods (more than six months) in the lifts filled during winter months. This was likely due to the high thermal insulation capability of the MSW and the low level of biological activity during start up. This observation indicates that bioreactor landfills located in cold climate and filled during winter months may require mechanisms to increase temperature and initiate biodegradation. Thus, besides moisture, temperature may be the next important factor controlling the biological decomposition in anaerobic bioreactor landfills. Spatial and temporal characterization of leachate samples indicated the presence of low levels of commonly used volatile organic compounds (including acetone, methyl ethyl ketone, methyl isobutyl ketone, and toluene) and metals (including arsenic, chromium, and zinc). Changes and leachate and gaseous sample characteristics correlated with enhanced biological activity and increase in temperature. Continued monitoring of this bioreactor landfill cell is expected to yield critical data needed for start up, design, and operation of this emerging process.

Zhao, Xiando; Voice, Thomas; and Hashsham, Syed A.

2006-08-29

370

Evolution of volcanic gas composition during repeated culmination of volcanic activity at Kuchinoerabujima volcano, Japan  

NASA Astrophysics Data System (ADS)

Chemical and isotopic compositions of low to medium temperature fumarolic gasses were measured at various fumaroles of Kuchinoerabujima volcano from 1993 to 2009 by the combination of fumarolic gas sampling and Multi-GAS measurement of volcanic plumes. Repeated culmination of the volcanic activity was observed as contemporaneous occurrence of seismic swarms, summit inflation and demagnetization, almost every two years after 1999. Fumarolic activity also increased parallel with these activities; new fumarolic fields of low-temperature fumaroles at boiling point formed at the southern and western rims of the summit crater in 2003 and intense degassing activity started at medium-temperature fumaroles inside the summit crater in 2008. The low-temperature fumarolic gasses have peculiar composition with high H 2/H 2O, CO/CO 2 and SO 2/H 2S ratios, typical features of high-temperature volcanic gasses, but also with low HCl and total S contents, typical features of low-temperature gasses. These features indicate that the gasses are formed by low-temperature differentiation of high-temperature gasses. Variation of H and O isotopic ratios of the low-temperature gasses indicates that the gasses are formed by isoenthalpic processes of vapor-liquid separation at 100 C of a high-temperature gas and meteoric water mixture, implying that the high-temperature gas was injected into a shallow aquifer without cooling. Temperatures of the high-temperature gasses were estimated as 550-700 C based on the equilibrium temperature calculation with considering the low-temperature differentiation. The medium-temperature fumarolic gasses from the summit crater have typical compositions of high-temperature volcanic gasses and are estimated as the source gas of the boiling point fumaroles. The H 2/H 2O and CO 2/S t ratios of the low-temperature fumaroles increased from 2004 to 2009, which is interpreted to be caused by the evolution of thermal structure of a shallow gas storage region of a few hundred meters deep. Increase of magmatic gas supply caused enlargement of a high-temperature zone of the gas storage region widening the surrounding temperature transit zone with smaller temperature gradient. The enlargement of the high-temperature zone also reduces the overlying low-temperature aquifer, which caused the decrease of CO 2/S t ratio by reduction of sulfur removal reaction. The enlargement of the high-temperature zone resulted in the leakage of the high-temperature gasses directly to the surface as the medium-temperature gasses from the summit crater.

Shinohara, H.; Hirabayashi, J.; Nogami, K.; Iguchi, M.

2011-04-01

371

TiO{sub 2}/PANI And MWNT/PANI Composites Thin Films For Hydrogen Gas Sensing  

SciTech Connect

The MWNT and TiO{sub 2} doped Polyaniline (PANI) composites were synthesized by In-situ chemical oxidative polymerization method at low temperature. The MWNT/PANI and TiO{sub 2}/PANI composite thin films were prepared using spin coating method onto finger type interdigited electrodes to develop the chemiresistor type gas sensor for hydrogen gas sensing application. It was observed that the MWNT and TiO{sub 2} doped PANI composite thin films show a higher response in comparision to neat PANI. The structural and morphological properties of these composite films were characterized by X-Ray differaction (XRD) pattern and sccaning electrone microscopy (SEM) respectively.

Srivastava, Subodh; Kumar, Sumit; Agrawal, Shweta; Saxena, Arpita; Choudhary, B. L.; Mathur, Shubhra; Singh, M.; Vijay, Y. K. [Department of Physics, University of Rajasthan, Jaipur-302004 (India)

2010-12-01

372

Emission characteristics and air-surface exchange of gaseous mercury at the largest active landfill in Asia  

NASA Astrophysics Data System (ADS)

The emission characteristics and air-surface exchange of gaseous elemental mercury (GEM) at Laogang landfill in Shanghai, China, the largest active landfill in Asia, has been investigated during two intensive field campaigns in 2011 and 2012. The mercury (Hg) content in municipal solid waste (MSW) varied widely from 0.19 to 1.68 mg kg-1. Over the closed cell in the landfill, the mean ambient air GEM concentration was virtually indistinguishable from the hemispherical background level (1.5-2.0 ng m-3) while the concentration downwind of ongoing landfill operation (e.g. dumping, burying and compacting of MSW) was clearly elevated. GEM emission through landfill gas (LFG) was identified as a significant source. GEM concentrations in LFGs collected from venting pipes installed in different landfill cells varied widely from 3.0 to 1127.8 ng m-3. The GEM concentrations were found negatively correlated to the age of LFG cells, suggesting GEM released through LFG declined readily with time. The GEM emission from this source alone was estimated to be 1.23-1.73 mg h-1. GEM emission from cover soil surfaces was considerably lower and at a scale comparable to that of background soil surfaces. This is in contrast to earlier reports showing enhanced GEM emissions from landfill surfaces in Southern China, probably due to the difference in soil Hg content and gas permeability characteristics of soils at different sites. Vertical concentration profiles of GEM in the interstitial gas of buried MSW were sampled, perhaps for the first time, which exhibited a wide spatial variability (4.9-713.1 ng m-3) in the 3-year-old landfill cell investigated. GEM emission from landfill operation was estimated to be 290-525 mg h-1 using a box model. This suggests that GEM degassing from Laogang landfill is quantitatively largely dominated by emissions from daily landfilling operations with a much smaller contribution from LFG venting and insignificant (bi-directional fluxes near zero) contribution from surfaces capped with a soil layer. This study reveals divergent GEM emission patterns among landfill cells of different ages, and provides essential emission estimates for formulating Hg emission reduction strategies for a large landfill.

Zhu, Wei; Li, Zhonggen; Chai, Xiaoli; Hao, Yongxia; Lin, Che-Jen; Sommar, Jonas; Feng, Xinbin

2013-11-01

373

Polymerization shrinkage evaluation of three packable composite resins using a gas pycnometer.  

PubMed

Modern restorative dentistry has been playing an outstanding role lately since composite resins, allied to adhesive systems, have been widely applied on anterior and posterior teeth restorations. The evolution of composite resins has mostly been verified due to the improvement of their aesthetic behavior and the increase in their compressive and abrasive strengths. In spite of these developments, the polymerization shrinkage inherent to the material has been a major deficiency that, so far, has been impossible to avoid. Using a gas pycnometry, this research investigated the polymerization shrinkage of three packable composite resins: Filtek P60 (3M), Prodigy Condensable (Kerr), and SureFil (Dentsply/Caulk), varying the distance from the light source to the surface of the resins (2 mm or 10 mm). The pycnometer Accupyc 1330 (Micromeritics, USA) precisely records helium displacement, allowing fast and reliable measurements of the volume of composite resin immediately before and after polymerization, without interference of temperature or humidity. Results were not found to be statistically different for the three tested resins, either for 2 mm or 10 mm-distance from the light source to the composite surface. PMID:14762507

Amore, Ricardo; Pagani, Clvis; Youssef, Michel Nicolau; Anauate Netto, Camillo; Lewgoy, Hugo Roberto

2003-01-01

374

Evaluating biotoxicity variations of landfill leachate as penetrating through the soil column.  

PubMed

Recent studies of leachate-induced ecotoxicity have focused on crude samples, while little attention has been given to changes in biotoxicity resulting from the environmental behavior of landfill leachate. Therefore, we set up a soil column to simulate the underground penetration of leachate into the soil layer, define the rules of migration and transformation of leachate pollutants, and determine the variation in toxicity of landfill leachate during penetration. The results demonstrated that: (1) landfill leachate inhibited the growth and chlorophyll levels, elevated the levels of lipid peroxidation and protein oxidation, and stimulated the antioxidant enzyme activities of barley seedlings. The effects generally displayed a peak value at 12-24 cm, slowly declined at 36-48 cm, and then rapidly decreased with penetrating distance in the column. (2) Statistical correlation analysis of the properties of leachate and the observed biotoxic effects revealed that COD, conductivity and heavy metals (esp. Ni, Mn, Cd) were positively correlated with variations in biotoxicity. (3) The microbial activity of outflowing leachate sampled from the 48 cm port was significantly higher than the activity from succedent ports, and the types of contaminants increased in the leachate outflowing from the same port, implying that microbial behaviors near the 48 cm port could be used to partially evaluate variations in the composition and biotoxicity of landfill leachate. Taken together, the above results illustrate the polluting characteristics of landfill leachate when penetrating a soil column and provide guidance for pollution control and risk assessment of landfill leachate. PMID:23522605

Zhu, Na; Ku, Tingting; Li, Guangke; Sang, Nan

2013-08-01

375

Wear behavior of gas tunnel type plasma sprayed Zr-based metallic glass composite coatings  

NASA Astrophysics Data System (ADS)

Gas tunnel type plasma spraying is a prospective method to produce metallic glass composite coatings with high quality due to its noteworthy feature of process controllability. In this study, Zr55Cu30Al10Ni5 metallic glass composite coatings were produced by gas tunnel type plasma spraying torch under optimum spraying conditions with selected plasma currents. The formation mechanism, sliding, and erosive wear behaviors of the coatings with respect to plasma current was examined. The phase and thermal analyses as well as microstructure of the plasma sprayed coatings produced at different plasma currents were characterized using X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) techniques. The sliding and erosive wear behaviors of the coatings were studied using a pin-on-disc and a specially designed erosive wear tester, respectively. The results showed that an increase in plasma current increased the crystalline content in the metallic glass composite coatings, which enhanced the hardness and wear resistance of the coatings.

Yugeswaran, S.; Kobayashi, A.; Suresh, K.; Rao, K. P.; Subramanian, B.

2012-09-01

376

Modelling flow to leachate wells in landfills  

Microsoft Academic Search

Vertical wells are frequently used as a means of controlling leachate levels in landfills. They are often the only available dewatering option for both old landfills without any basal leachate collection layer and for newer sites where the installed drainage infrastructure has failed. When the well is pumped, a seepage face develops at the entry into the well so that

A. A. Al-Thani; R. P. Beaven; J. K. White

2004-01-01

377

Biological control of leachate from municipal landfills  

Microsoft Academic Search

Landfilling is still a popular way for municipal solid waste (MSW) treatment. Leachate generated from landfills is becoming a great threat to the surroundings as it contains high concentrations of toxic substances. How to control leachate migration and to protect environmental pollution is now a concern for many environmentalists. In this work, eight effective microorganisms (EMs) were isolated from wastewater,

Aizhong Ding; Zonghu Zhang; Jiamo Fu; Lirong Cheng

2001-01-01

378

MONITORING APPROACHES FOR BIOREACTOR LANDFILLS - Report  

EPA Science Inventory

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

379

Landfill Leachate Disposal with Irrigated Vetiver Grass  

Microsoft Academic Search

Stotts Creek Landfill is a major waste depot of the Tweed Shire receiving wastes from both Tweed Heads and Murwillumbah townships and neighboring local government areas. Disposal of leachate is a major concern of the Shire as the landfill site is close to agricultural areas. An effective and low cost leachate disposal system is needed, particularly during summer high rainfall

Ian Percy; Paul Truong

380

Identification of dynamic properties of OII landfill  

SciTech Connect

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 materials behaved as essentially a linear viscoelastic material, showing a negligible reduction in shear modulus with shear strain amplitude. The damping responsible for energy dissipation was found to depend on frequencies between 0.1 and 10 Hz. The physical origins of this frequency-dependent damping are not yet clearly understood. The results of this study are useful in analyzing the dynamic response of landfills and cap systems during small to moderate-size earthquakes. The present analysis is simplified because there were only two recording instruments at the OII landfill. It is recommended that researchers deploy more field instruments at this and other landfills to document their dynamic response during future earthquakes, and develop large-scale laboratory tests to determine landfill material properties under large static and dynamic strains.

Morochnik, V.; Bardet, J.P.; Hushmand, B. [Univ. of Southern California, Los Angeles, CA (United States). Dept. of Civil Engineering

1998-03-01

381

Field Water Balance of Landfill Final Covers  

EPA Science Inventory

Landfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side-by-side testing. A study was conducted to assess the ability of landfill final covers to control percolation into unde...

382

Relationship between fumarole gas composition and eruptive activity at Galeras Volcano, Colombia  

SciTech Connect

Forecasting volcanic eruptions is critical to the mitigation of hazards for the millions of people living dangerously close to active volcanoes. Volcanic gases collected over five years from Galeras Volcano, Colombia, and analyzed for chemical and isotopic composition show the effects of long-term degassing of the magma body and a gradual decline in sulfur content of the gases. In contrast, short-term (weeks), sharp variations are the precursors to explosive eruptions. Selective absorption of magmatic SO{sub 2} and HCl due to interaction with low-temperature geothermal waters allows the gas emissions to become dominated by CO{sub 2}. Absorption appears to precede an eruption because magmatic volatiles are slowed or retained by a sealing carapace, reducing the total flux of volatiles and allowing the hydrothermal volatiles to dominate gas emissions. Temporal changes in gas compositions were correlated with eruptive activity and provide new evidence bearing on the mechanism of this type of `pneumatic` explosive eruptions. 18 refs., 5 figs.

Fischer, T.P.; Williams, S.N. [Arizona State Univ., Tempe, AZ (United States)] [Arizona State Univ., Tempe, AZ (United States); Arehart, G.B.; Sturchio, N.C. [Argonne National Lab., IL (United States)] [Argonne National Lab., IL (United States)

1996-06-01

383

Composition and method for treating flue gas and methanol containing effluents  

SciTech Connect

A composition is provided which comprises an aqueous alkaline solution of a metal salt and black liquor, the metal salt being selected from the group consisting of iron, chromium, cobalt and nickel salts. This composition is useful in a process described for absorption of hydrogen sulfide from flue gas, followed by subsequent oxidation of dissolved sulfide to thiosulfate, if desired. The presence of the metal ions and black liquor synergistically catalyzes the overall reaction of absorption of hydrogen sulfide, followed by oxidation of the sulfide. Preferably, prior to scrubbing to remove hydrogen sulfide with the solution, the flue gas is first cooled to near its dew point, and then scrubbed with water to remove particulates. Additionally, the effluent flue gas from the absorption step is usefully scrubbed with water to recover heat, following which it is used to scrub condensates from a kraft pulp mill. The metal salt in the solution is preferably an iron salt at a concentration of about 0.002 M., the black liquor concentration being preferably about 1% to 5% by volume of the solution, and the pH being usefully about 9.0 to 9.5.

Murray, F. E.

1985-03-19

384

Toxicity Assessment of Contaminated Soils of Solid Domestic Waste Landfill  

NASA Astrophysics Data System (ADS)

The paper delivers the analysis of an 18-year dynamic pattern of land pollutants concentration in the soils of a solid domestic waste landfill. It also presents the composition of the contaminated soils from different areas of the waste landfill during its operating period. The authors calculate the concentrations of the following pollutants: chrome, nickel, tin, vanadium, lead, cuprum, zinc, cobalt, beryllium, barium, yttrium, cadmium, arsenic, germanium, nitrate ions and petrochemicals and determine a consistent pattern of their spatial distribution within the waste landfill area as well as the dynamic pattern of their concentration. Test-objects are used in experiments to make an integral assessment of the polluted soil's impact on living organisms. It was discovered that the soil samples of an animal burial site are characterized by acute toxicity while the area of open waste dumping is the most dangerous in terms of a number of pollutants. This contradiction can be attributed to the synergetic effect of the polluted soil, which accounts for the regularities described by other researchers.

Pasko, O. A.; Mochalova, T. N.

2014-08-01

385

Lantana landfill: A history of environmental management 1965--96  

SciTech Connect

The Lantana Sanitary Landfill (LSL) is located in central Palm Beach County, Florida. The history of this landfill is a case study of the changes in environmental law, demography, solid waste management, hydrogeology, and public opinion in south Florida in the last 30 years. In 1983 Palm Beach County transferred ownership of the LSL to the Palm Beach County Solid Waste Authority (SWA). Environmental regulation enacted by Florida in the mid 1980`s resulted in negotiations to close the LSL. Closure was completed in 1988 utilizing a synthetic top liner, a landfill gas extraction/flare system, and a stormwater management system. In 1990 a groundwater mitigation system was installed to remediate the eastern plume. Closure of the LSL, extension of municipal water to local residents, and extensive public education by the SWA all served to answer most of the complaints of the local residents. In 1996 the LSL fell under a new series of air regulations and was required to apply for a Title V permit.

Statom, R.A. [Solid Waste Authority of Palm Beach County, West Palm Beach, FL (United States)

1997-08-01

386

Thermal-shock behavior of advanced ceramic/composite hot-gas filters  

SciTech Connect

The thermal shock/fatigue behavior of monolithic and composite hot-gas candle filters obtained from various manufacturers was evaluated. The composite filters were made of both oxide and nonoxide materials; the monolithic filters were made only of nonoxide materials. During single-cycle thermal shock tests, composite filters show little or no strength degradation when quenched from temperatures between 900 and 1000{degrees}C. At higher quenching temperatures, slow strength degradation was observed. Regular monolithic SiC filters showed no strength degradation when quenched from temperatures up to {approx}700-900{degrees}C, whereas at higher quenching temperatures, the strength decreased at a relatively sharper rate. On the other hand, recrystallized monolithic SiC filters showed higher initial strength and retained this strength to higher quenching temperatures when compared with regular SiC filters. This finding may be related to the difference in the strength of grain boundary phases in the two filters. For thermal cycles between room temperature and 800-1000{degrees}C, composite filters show little (18-24%) strength degradation up to three cycles, beyond which the strength remains unchanged. Similar behavior, with an initial strength drop of 15-28%, was observed for monolithic filter specimens that were thermally cycled between room temperature and 800{degrees}C.

Singh, J.P.; Sutaria, M.; Bielke, W.

1997-02-01

387

Structural transition in mixed hydrates of xenon and krypton as a function of gas composition  

SciTech Connect

Six samples of mixed hydrates of structure I former Xe and structure II former Kr were prepared from gas mixtures in which the concentration of Xe varied from 1 to 24 mol %. The structures and compositions of the hydrates were studied by X-ray diffraction, NMR, and calorimetry. In all cases, there was significant enrichment of Xe in the hydrate phase. The structure of the mixed hydrate changed from structure II to structure I when the initial concentration of Xe in the gas mixture was 5 mol % or more. The results show that the structure of the mixed hydrate is primarily determined by the component having the larger Cf, where C is the Langmuir constant and f the partial fugacity.

Handa, Y.P.; Ratcliffe, C.I.; Ripmeester, J.A.; Tse, J.S. (National Research Council of Canada, Ottawa, Ontario (Canada))

1990-05-17

388

Novel BN/Pd composite films for stable liquid petroleum gas sensor  

NASA Astrophysics Data System (ADS)

Composite films of BN/Pd were synthesized by depositing thin films of BN by pulsed laser deposition technique and evaporating a thin layer of palladium on top of it to form a bi-layer structure. This bi-layer structure was then subjected to rapid thermal annealing for the incorporation of Pd in BN. The films thus obtained were characterized by SEM, XRD and FTIR studies. Liquid petroleum gas (LPG) sensing properties were also investigated critically. Very stable and reproducible LPG sensing properties and comparatively at lower operating temperature of 460 K would make this material superior to prevalent oxide based sensors.

Ghosh, D.; Ghosh, B.; Hussain, S.; Chaudhuri, Subhajyoti; Bhar, R.; Pal, A. K.

2012-12-01

389

Mechanical behavior of ceramic composite hot-gas filters after exposure to severe environments  

SciTech Connect

A novel type of hot-gas filter based on a ceramic fiber reinforced ceramic matrix has been developed, as reported at previous Fossil Energy Materials Conferences, through research activities at Oak Ridge National Laboratory (ORNL) and at the 3M Company. Simulated testing has been done at the Westinghouse Science and Technology Center. This filter technology has been extended to full size, 60 mm OD by 1.5 meter long candle filters and a commercially viable process for producing the filters has been developed filters are undergoing testing and demonstration use throughout the world for applications in pressurized fluidized-bed combustion (PFBC) and integrated gasification combined cycle (IGCC) plants. Demonstration tests of this ceramic composite filter along with other filters are in progress at the Tidd PFBC plant Mechanical tests were performed on the 3 M brand Ceramic Composite Candle Filter after exposure to various corrosive environments in order to assess its ability to function as a hot gas filter in coal-fired applications. Due to the different construction of ceramic composite filters and the thin composite wall versus the typical thick-walled monolithic filter, standard mechanical property tests had to be refined or modified to accurately determine the filters properties. These tests and filter property results will be described Longitudinal tensile and diametral O-ring compression tests were performed on as-produced candle filters as well as on filters which had been exposed to various environments. The exposures were for 1000 hrs at 850{degrees}C in wet air, in wet air containing Na{sub 2}CO{sub 3}, and in wet air containing NaCl. In addition, a filter which bad been coated with ash (Old Grimethorpe) was exposed to wet air at 850{degrees}C for 1000 hours.

Pysher, D.J.; Weaver, B.L.; Smith, R.G. [Ceramic Technology Center, St. Paul, MN (United States)] [and others

1995-08-01

390

Superfund Record of Decision (EPA Region 2): Old Bethpage Landfill, Old Bethpage, New York (first remedial action), March 1988. Final report  

SciTech Connect

The Old Bethpage landfill, covering approximately 65 acres, is located in Old Bethpage, Town of Oyster Bay, Nassau Country, New York. Two public drinking-water wells, a residential community, an industrial park, and a state park, exist within the site's general vicinity. Beginning in 1958, the Town of Oyster Bay operated the landfill as a municipal landfill. In addition to accepting municipal wastes and garbage, local industrial wastes were disposed of on the landfill during the late 1960s and early 1970s. A system designed to collect, store, treat, and dispose of leachate has been operating at the site since 1983. There are three remedial actions currently underway at the site. They include: leachate collection, methane gas collection, and landfill capping. The primary contaminants of concern affecting ground water include: VOCs, TCE, benzene, toluene, inorganics, chromium, and lead. Air is contaminated with methane gas and VOCs.

Not Available

1988-03-17

391

Landfills as critical infrastructures: synergy between non-invasive monitoring technologies  

NASA Astrophysics Data System (ADS)

This work deals with a methodology for estimating the behaviour of a landfill system by means of the integration between two different non-invasive technologies. In fact, there is a widespread agreement on the fact that these infrastructures produce about 23% of the total anthropogenic methane released to the atmosphere. Despite that, there's still no internationally accepted protocol to quantify the leakage of biogas from a landfill with a common standard approach. This work proposes an assessment of the performance of a landfill system in terms of biogas release to the atmosphere. Such evaluation is performed by means of a direct measurement of gas flux with the accumulation chamber method, combined with the detection of thermal anomalies by infrared radiometry. In order to derive flux maps from a set of punctual measurements and calculate an overall quantity of emitted gas, a geostatistical technique is necessarily applied and briefly illustrated. A case study regarding an infrastructure located in Tuscany (Italy) is shown, where a discussion about the evolution of the landfill site through successive campaigns is also suggested. The role played by infrared thermography and its synergy with direct flux measurements is clearly perceivable in this context. The main benefit of the presented approach is a significant increase of the energy recovered from the landfill sites by optimising the collection of biogas, which implies a reduction of the total anthropogenic methane originated from the disposal of wastes released to the atmosphere.

Scozzari, Andrea; Raco, Brunella; Battaglini, Raffaele

2014-05-01

392

T2LBM Version 1.0: Landfill bioreactor model for TOUGH2  

SciTech Connect

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 biodegradation of municipal solid waste and the associated flow and transport of gas and liquid through the refuse mass. T2LBM incorporates a Monod kinetic rate law for the biodegradation of acetic acid in the aqueous phase by either aerobic or anaerobic microbes as controlled by the local oxygen concentration. Acetic acid is considered a proxy for all biodegradable substrates in the refuse. Aerobic and anaerobic microbes are assumed to be immobile and not limited by nutrients in their growth. Methane and carbon dioxide generation due to biodegradation with corresponding thermal effects are modeled. The numerous parameters needed to specify biodegradation are input by the user in the SELEC block of the TOUGH2 input file. Test problems show that good matches to laboratory experiments of biodegradation can be obtained. A landfill test problem demonstrates the capabilities of T2LBM for a hypothetical two-dimensional landfill scenario with permeability heterogeneity and compaction.

Oldenburg, Curtis M.

2001-05-22

393

Attenuation of Landfill Leachate In Unsaturated Sandstone  

NASA Astrophysics Data System (ADS)

Landfill leachate emanating from old "dilute and disperse" sites represents a potential (and in many cases actual) threat to the integrity of groundwater. Indeed, this concern has been included in EU legislation (80/86/EEC), where key contaminants (e.g. ammonia, various toxic organic compounds and heavy metals) are explicitly highlighted in terms of their impact on groundwater. In the UK, whilst there are a substantial number of unlined landfills sited on major aquifers, many of these are in locations where there is a substantial unsaturated zone. Thus, there exists the opportunity for the modification and attenuation of contaminants prior to it encountering the water table. An understanding of likely changes in leachate content and concentrations at such sites will enable a more comprehensive assessment of the potential risks and liabilities posed by such sites to be evaluated. The Burntstump landfill, situated 8 km north of Nottingham (UK), is sited on an outcrop of Sherwood sandstone. The fine friable sand has been quarried since the 1960s and the excavated volume used to store municipal waste. Filling at the site commenced in the mid 1970s and originally was unlined. In 1978 the first of what was to become a series of boreholes was installed within an area of roughly 5 m radius over one of the original waste cells. Cores of the waste and underlying sandstone were extracted and analysed for a range of physical and chemical parameters. The most recent set of analyses were obtained in 2000. The series of investigations therefore provide an important record of leachate migration and modification through the unsaturated zone for over twenty years. The progression of the leachate front is clearly delineated by the chloride concentration profile with an average velocity of around 1.6 m.yr-1. Combining this value with an average (and reasonably uniform) measured moisture content of about 7% gives a mean inter-granular specific discharge of 110 mm.yr-1. An interesting feature of the sequences of porewater concentration profiles is the sharp leading front of the Cl plume. Thus indicating that very little solute dispersion appears to be occurring. This is probably to be due to the relatively uniform particle size of the sand matrix combined with the low moisture content, which has greatly constrained the available pore sizes in which flow occurs. A marked reduction in the mass of the chloride plume has been observed over the last 13 years. Analyses of core sample taken in 2000 show that the Cl profile has continued to lose mass and has now also separated into two peaks. The leading peak was located at a depth of 36 m below ground level (28 m below the base of the landfill) and in line with model predictions. The trailing peak was at a depth of 27 m bgl and was associated with a 0.3 m layer of marl and clay bands. Thus there is an indication that the changes in chloride mass are possibly due to the effects of heterogeneity, although other processes which could account for chloride removal from solution are also under consideration. The location of the TOC front up to 1992 was commensurate with that of Cl, indicating no effective retardation. This is consistent with the very low levels of organic carbon present in the sandstone. However, marked reductions in contaminant mass (substantially greater than those of Cl) have been observed. Analyses of volatile fatty acids has indicated a progressive breakdown of VFA components leading to simpler products so that by 1991 the dominant component was ethanoic acid (56% by mass). By 2000 the entire leading front of the TOC was absent. TOC was only found to be present at relatively low concentrations ( 100 mg.l-1) above the marl/clay band. Analyses of gas concentrations at the site have indicated that there has been a change in the redox potential in the volume of contaminated unsaturated sandstone below the waste cells during the last 10 years. With predominantly anaerobic conditions giving way to aerobic. This change appears to be related to the introduction of a landfill gas ex

Butler, A. P.; Brook, C.; Godley, A.; Lewin, K.; Young, C. P.

394

FRASER BASIN LANDFILL INVENTORY DOE FRAP 1997-19  

E-print Network

; 2. Develop a quantitative estimate of landfill leachate discharges for each landfill; 3. Assess landfill compliance with regulatory requirements; 4. Assess leachate discharge impacts on the receiving proposed scope of work. Estimates of annual municipal landfill leachate volumes were based on waste

395

Spectroscopic studies of the effect of aerobic conditions on the chemical characteristics of humic acid in landfill leachate and its implication for the environment.  

PubMed

Humic acids (HAs) that extracted from leachates from semi-aerobic and anaerobic landfills test field at different stabilization times were characterized by elemental composition, Fourier transform infrared spectroscopy (FTIR), and Carbon-13 Cross-Polarization Magic-Angle-Spinning Nuclear Magnetic Resonance ((13)C CP/MAS NMR). The higher sulfur (S) content of HA in the anaerobic landfill leachate after a short stabilization time showed that the S released from the organic matter degradation was more easily stabilized under anaerobic conditions, which indicate that HA from anaerobic landfill leachate was more chemically reactive and played a more important role in mobilizing heavy metal, especially mercury, at early landfill stabilization times. However, the S content of HA from the semi-aerobic landfill increased over time, suggesting that more S was stabilized in HA as the landfill stabilization time was extended. The analytical results for the FTIR and NMR showed that the HA from the anaerobic landfill contained more aromatic groups, while HA from the semi-aerobic landfill had more oxygen-containing groups. The aromatic components of the HA from both the anaerobic and semi-aerobic landfills increased over time, suggesting that the maturity and humification degree of HA increased during the stabilization process. PMID:23461837

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

2013-05-01

396

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

Microsoft Academic Search

This study evaluates the environmental performance and discounted costs of the incineration and landfilling of municipal solid waste 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

Bernadette Assamoi; Yuri Lawryshyn

397

What measurements tell us about air composition and emissions in three US oil and gas fields  

NASA Astrophysics Data System (ADS)

In 2012 and 2013, the NOAA Global Monitoring Division and several collaborators conducted intensive airborne and ground campaigns in three US oil and gas plays to study emissions of methane and surface ozone precursors. In this presentation we will focus on the multiple species analysis in discrete air samples collected with the NOAA Mobile Laboratory (ML) and the light aircraft in the Uinta Basin (Utah), Denver Julesburg Basin (Colorado) and Barnett Shale (Texas). Hydrocarbon ratios in samples collected with the ML downwind of specific sources show significantly more variability than the aircraft samples. These surface samples provide some useful information about the composition of various sources in each region. Ratios of the non-methane hydrocarbons on the ground and higher in the boundary layer show some differences between the plays, which could be explained by the different composition of the raw gas being produced or by different mixes of sources contributions. Understanding the speciation of atmospheric emissions is critical to identify emission vectors and to assess their potential air quality and climate impacts. Our measurement results will be compared with data from other studies, including emission inventories.

Petron, G.; Miller, B. R.; Montzka, S. A.; Dlugokencky, E. J.; Kofler, J.; Sweeney, C.; Karion, A.; Frost, G. J.; Helmig, D.; Hueber, J.; Schnell, R. C.; Conley, S. A.; Tans, P. P.

2013-12-01

398

Optical absorption method of natural gas component analysis in real time. Part II. Analysis of mixtures of arbitrary composition  

NASA Astrophysics Data System (ADS)

The present paper continues the presentation of the results of studies started in [1]. The referred paper reports the development of the optical method for component analysis of natural gas mixtures with different compositions, allowing conducting measurements in real time. The method is based on the measurement of the absorption coefficients for the analyzed gas mixture at several wavelengths within the infrared region of the spectrum (7-14 ?m), with the selected number and values of wavelengths depending on the category of the gas mixture. The resulting accuracy of the determination of the main components of gas mixtures including methane, ethane, propane, butane, pentane and carbon dioxide is sufficient for the use of the developed method for the monitoring of the component composition of natural gas in pipelines.

Kireev, S. V.; Podolyako, E. M.; Simanovsky, I. G.; Shnyrev, S. L.

2012-10-01

399

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

NASA Astrophysics Data System (ADS)

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 mixtures contained carbon dioxide, nitrogen, ethane, propane and n-butane in methane (matrix) and were only to a limited extent representative of real natural gas. In the past years, national metrology institutes have broadened the range of components by including, e.g., i-butane, neo-pentane, n-pentane, i-pentane and n-hexane. Based on this extended components list, two new mixtures have been defined, one characteristic for a low calorific mixture (type IV) and the other for a high calorific mixture (type V). In the low calorific mixture, helium was also present. Due to presence of the butane and pentane isomers, the mixtures of type IV and V are more demanding with respect to the separation technique than the mixtures used in CCQM-K1e-g. The measurements in this key comparison took place in 2001. There were eight participants and two coordinating laboratories. The key comparison reference value (KCRV) was based on the gravimetric preparation for all components. Even for the heavier hydrocarbons (pentanes and n-hexane) the effects of, e.g., adsorption can be controlled to such an extent that this approach is still valid. The uncertainty evaluation of the KCRVs reflected also the extent to which the preparation data could be demonstrated to be valid. The validity of the preparation data was demonstrated by comparing the composition of the mixtures prepared for this comparison with measurement standards maintained by the coordinating laboratories. The key comparisons demonstrated that the results of the laboratories agreed within 1% relative to the reference value for most components. Even better agreement was obtained for nitrogen in the low calorific mixture (0.5%), carbon dioxide (0.5%), ethane (0,5%), propane (0.5%) and methane (0.1%). In some cases, larger differences were observed, which then also exceeded the associated expanded uncertainty Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the Mutual Recognition Arrangement (MRA).

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

2005-01-01

400

Reverse osmosis module successfully treats landfill leachate  

SciTech Connect

By law, modern landfills are to be constructed with double liners to prevent contaminants from leaching into surface and ground water. Despite this design feature, however, both hazardous and non-hazardous compounds do leach from the waste disposed in landfills. The resulting contaminated water, or leachate, must be collected and treated. Rochem Environmental, Inc. (Houston, Texas) has developed a new membrane process, known as the Disc Tube{trademark} system, to remove a variety of contaminants from landfill leachate. 1 ref., 1 fig., 2 tabs.

NONE

1995-03-01

401

Influence of a municipal solid waste landfill in the surrounding environment: toxicological risk and odor nuisance effects.  

PubMed

The large amounts of treated waste materials and the complex biological and physicochemical processes make the areas in the proximity of landfills vulnerable not only to emissions of potential toxic compounds but also to nuisance such as odor pollution. All these factors have a dramatic impact in the local environment producing environmental quality degradation. Most of the human health problems come from the landfill gas, from its non-methanic volatile organic compounds and from hazardous air pollutants. In addition several odorants are released during landfill operations and uncontrolled emissions. In this work we present an integrated risk assessment for emissions of hazard compounds and odor nuisance, to describe environmental quality in the landfill proximity. The study was based on sampling campaigns to acquire emission data for polychlorinated dibenzo-p-dioxins and dibenzofurans, dioxin-like polychlorobiphenyls, polycyclic aromatic hydrocarbons, benzene and vinyl chloride monomer and odor. All concentration values in the emissions from the landfill were measured and used in an air dispersion model to estimate maximum concentrations and depositions in correspondence to five sensitive receptors located in proximity of the landfill. Results for the different scenarios and cancer and non-cancer effects always showed risk estimates which were orders of magnitude below those accepted from the main international agencies (WHO, US EPA). Odor pollution was significant for a limited downwind area near the landfill appearing to be a significant risk factor of the damage to the local environment. PMID:24685488

Palmiotto, Marinella; Fattore, Elena; Paiano, Viviana; Celeste, Giorgio; Colombo, Andrea; Davoli, Enrico

2014-07-01

402

Performance of a passively vented field-scale biofilter for the microbial oxidation of landfill methane.  

PubMed

An upflow biofilter system was operated on a passively vented landfill for the treatment of residual landfill methane. Biofilter methane emissions as a basis for determining methane removal rates were assessed by manual and automated chamber measurements, by measuring methane concentrations in the top layer gaseous phase in combination with gas flow rates, and by evaluating the methane load in the reverse gas flow following the change of landfill gas flux direction as governed by the course of barometric pressure. Methane removal rates were very high with maximum values of 80 g h(-1) m(-3). For the observed cases, the limit of biofilter methane oxidation capacity was not reached and absolute removal rates were thus linearly correlated to the amount of methane entering the filter. The analysis of methane loads flowing back from the biofilter following phases of longer, continuous and non-oscillating landfill gas emission, however, revealed that in these situations biofilter performance is restricted by deficient oxygen supply. At the oxygen-restricted capacity limit, removal rates are influenced by temperature (positively), methane influx (negatively) and flow rate (negatively) as a measure for the displacement of oxygen. These situations, however, account for only 12% of all emission phases. The investigated biofilter capacity, as derived from laboratory analyses of methanotrophic activities, is sufficient to oxidise 62% of the methane load emitted annually. Field and laboratory data provide a stable basis for the dimensioning of filters in future applications. PMID:16386887

Gebert, J; Grngrft, A

2006-01-01

403

PERFORMANCE OF NORTH AMERICAN BIOREACTOR LANDFILLS: II. CHEMICAL AND BIOLOGICAL CHARACTERISTICS  

EPA Science Inventory

The objective of this research was to examine the performance of five North American bioreactor landfills. This paper represents the second of a two part series and addresses biological and chemical aspects of bioreactor performance including gas production and management, and l...

404

Factors Controlling Concentration of Metals in the Leachate from Aerobic and Anaerobic Laboratory Landfill Bioreactors  

NASA Astrophysics Data System (ADS)

Costs and environmental issues associated with operating municipal landfills have motivated laboratory experiments investigating methods to increase biodegradation and decrease fugitive emissions of both liquid and gas. Rates of settling, biodegradation, and emissions were measured in three large laboratory-scale bioreactors filled with 30 kg of typical municipal waste. The bioreactors (200-L clear acrylic tanks) were instrumented to monitor pressure, temperature, moisture, humidity, gas composition, and leachate composition. Three treatments were applied: 1) aerobic (air injection with water addition and recirculation), 2) anaerobic (no air injection, water addition and recirculation), and 3) a control tank (no air or water injection). Preliminary studies showed measurable concentrations of Fe, Ba, Cu, Al, Mn, Ni, and Zn in the leachate. To investigate this further, bi-weekly leachate samples were, and were analyzed for dissolved Fe, Ba, Cu, Al, Mn, Ni, Zn. NO3-, NO2-, NH4+, PO43-, SO42-, Cl-, Fl-, Na+, Ca2, total organic acid, Eh and pH. The aerobic tank leachate had metals concentrations that were an order of magnitude lower than the leachate from the anaerobic tank. Possible explanations include the existence of fewer organic-metal complexes due to the decrease in the dissolved organic matter in the leachate for the aerobic treatment, or the higher pH and redox potential in the aerobic treatment. A sensitivity analysis was performed using MINTEQA2, a U.S. EPA geochemical speciation model that reports on metal speciation based on water composition parameters, for a combination of actual and estimated data. Initial results suggest that the presence of certain organic acids dramatically increases the metal-organic complexation, consistent with observations of greater metal concentrations in the anaerobic treatment leachate. This work was supported by Laboratory Directed Research and Development Funds at Lawrence Berkeley National Laboratory under Department of Energy Contract No. DE-AC03-76SF00098.

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

2001-12-01

405

Evaluation of Y-12 landfill  

SciTech Connect

The purpose of this project was to provide team members with practical experience in application of Civil Engineering 555, Solid Waste Management principles. Team members chose to evaluate the functional elements of the Oak Ridge Y-12 Plant's (Y-12's) solid waste management system. The following factors contributed to selection of Y-12'system for evaluation: team members' familiarity with the Y-12 system; knowledge that the Y-12 Centralized Sanitary Landfill II was nearing capacity; and presence of the unique issues posed by special national security and potential radioactive contamination considerations. This report was limited to evaluation of the solid waste management system for conventional solid waste; hazardous radioactive, and radioactive mixed waste were not addressed. The report: (1) describes each functional element including waste generation, storage, collection, transport, processing, recovery, and disposal; (2) identifies and evaluates alternatives for each element and (3) identifies system strengths and recommends opportunities for improvement. 34 figs.

Crawford, G.A. (Bechtel National, Inc., San Francisco, CA (USA)); Daugherty, D.L. (Oak Ridge National Lab., TN (USA)); Hutzler, C.W.; Smith, C.M. (Oak Ridge Y-12 Plant, TN (USA)); Wylie, A.N. (Adams, Craft, Herz, Walker, Inc., Oak Ridge, TN (USA))

1990-12-12

406

Life cycle assessment (LCA) of solid waste management strategies in Tehran: landfill and composting plus landfill.  

PubMed

As circumstances of operating and maintenance activities for landfilling and composting in Tehran metropolis differ from those of cities in developed countries, it was concluded to have an environmental impact comparison between the current solid waste management (MSW) strategies: (1) landfill, and (2) composting plus landfill. Life cycle assessment (LCA) was used to compare these scenarios for MSW in Tehran, Iran. The Eco-Indicator 99 is applied as an impact assessment method considering surplus energy, climate change, acidification, respiratory effect, carcinogenesis, ecotoxicity and ozone layer depletion points of aspects. One ton of municipal solid waste of Tehran was selected as the functional unit. According to the comparisons, the composting plus landfill scenario causes less damage to human health in comparison to landfill scenario. However, its damages to both mineral and fossil resources as well as ecosystem quality are higher than the landfill scenario. Thus, the composting plus landfill scenario had a higher environmental impact than landfill scenario. However, an integrated waste management will ultimately be the most efficient approach in terms of both environmental and economic benefits. In this paper, a cost evaluation shows that the unit cost per ton of waste for the scenarios is 15.28 and 26.40 US$, respectively. Results show landfill scenario as the preferable option both in environmental and economic aspects for Tehran in the current situation. PMID:20924666

Abduli, M A; Naghib, Abolghasem; Yonesi, Mansoor; Akbari, Ali

2011-07-01