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1

Temporal variability of soil gas composition in landfill covers  

Microsoft Academic Search

In order to assess the temporal variability of the conditions for the microbial oxidation of methane in landfill cover soils and their driving variables, gas composition at non-emissive and strongly emissive locations (hotspots) was monitored on a seasonal, daily and hourly time scale on an old, unlined landfill in northern Germany. Our study showed that the impact of the various

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

2011-01-01

2

Temporal variability of soil gas composition in landfill covers.  

PubMed

In order to assess the temporal variability of the conditions for the microbial oxidation of methane in landfill cover soils and their driving variables, gas composition at non-emissive and strongly emissive locations (hotspots) was monitored on a seasonal, daily and hourly time scale on an old, unlined landfill in northern Germany. Our study showed that the impact of the various environmental factors varied with the mode of gas transport and with the time scale considered. At non-emissive sites, governed by diffusive gas transport, soil gas composition was subject to a pronounced seasonal variation. A high extent of aeration, low methane concentrations and a high ratio of CO(2) to CH(4) were found across the entire depth of the soil cover during the warm and dry period, whereas in the cool and moist period aeration was less and landfill gas migrated further upward. Statistically, variation in soil gas composition was best explained by the variation in soil temperature. At locations dominated by advective gas transport and showing considerable emissions of methane, this pattern was far less pronounced with only little increase in the extent of aeration during drier periods. Here, the change of barometric pressure was found to impact soil gas composition. On a daily scale under constant conditions of temperature, gas transport at both types of locations was strongly impacted by the change in soil moisture. On an hourly scale, under constant conditions of temperature and moisture, gas migration was impacted most by the change in barometric pressure. It was shown that at diffusion-dominated sites complete methane oxidation was achieved even under adverse wintry conditions, whereas at hotspots, even under favorable dry and warm conditions, aerobic biological activity can be limited to the upper crust of the soil. PMID:21074982

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

2011-05-01

3

MUNICIPAL LANDFILL GAS CONDENSATE  

EPA Science Inventory

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

4

LANDFILL GAS MEASUREMENT METHODS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Methane from landfills contributes to greenhouse gas emissions. The development of cost-effective methods for measuring diffuse emissions from landfills remains a difficult issue for regulators and landfill operators. Currently, two major options are available: (1) above-ground methods which quantif...

5

Tracing landfill gas migration using chlorofluorocarbons  

Microsoft Academic Search

Typical landfill gas (LFG) compositions include a wide range of trace-level Volatile Organic Compounds (VOCs). The most mobile VOCs are chlorofluorocarbons (CFCs), and their presence around landfills may reflect the initial flushing out of VOCs during the early aerobic stage when landfills are most active reaching high temperatures, driving off VOCs, and injecting LFG into the surrounding environment. CFCs are

M. Archbold; T. E. Elliot; K. Redeker; G. Boshoff

2003-01-01

6

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...

7

LANDFILL GAS PRODUCTION FROM LARGE LANDFILL SIMULATORS  

EPA Science Inventory

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

8

Numerical simulation of landfill gas pressure distribution in landfills.  

PubMed

Landfill gas emissions are recognized as one of the three major concerns in municipal solid waste landfills. There are many factors that affect the generation of landfill gas when the landfill is capped. In this article, a model has been developed based on the theory of porous media flow. The model could predict the pressure distribution of landfill gas in landfill, coupling the effect of landfill settlement. According to the simulation analysis of landfill, it was found that: (a) the landfill gas pressure would reach a peak after 1.5 years, then begin to decline, and the rate of decay would slow down after 10 years; (b) the influence radius of the gas wells is limited; (c) the peak value of landfill gas pressure is larger, it appears later and the rate of decay is slower when the landfill settlement is considered in the model; (d) the calculation of excess gas pressure in landfill under different negative pressures of the extraction well is compared between this model and another model, and the results show that the relative pressure distribution form and range are almost the same. PMID:24019384

Xi, Yonghui; Xiong, Hao

2013-11-01

9

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

PubMed

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

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

2013-06-01

10

Beneficial use of landfill gas at the Burnsville sanitary landfill  

SciTech Connect

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

Michels, M. [Camp Dresser & McKee Inc., Milwaukee, WI (United States); Morely, J.; Kitts, S. [Edward Kraemer & Sons, Inc., Burnsville, MN (United States)

1995-08-01

11

Tracing landfill gas migration using chlorofluorocarbons  

NASA Astrophysics Data System (ADS)

Typical landfill gas (LFG) compositions include a wide range of trace-level Volatile Organic Compounds (VOCs). The most mobile VOCs are chlorofluorocarbons (CFCs), and their presence around landfills may reflect the initial flushing out of VOCs during the early aerobic stage when landfills are most active reaching high temperatures, driving off VOCs, and injecting LFG into the surrounding environment. CFCs are aerobically stable and therefore, may prove a useful means of characterising the environmental impact of landfill gas in the unsaturated zone around landfills. Moreover, as a possible pathfinder environmental tracer of LFG impacts in the environment, any subsequent changes in the CFCs concentrations after injection potentially reflect natural attenuation (NA) processes, which can also affect other VOCs. Thus tracing the CFCs around a landfill may provide an analogue indicator/proxy for other VOCs transport and fate. To assess the feasibility of using chlorofluorocarbons (CFC-11, CFC-12, CFC-113) as proxy tracers, it is imperative to characterise the effects of possible NA processes on both CFC abundances and their overall systematics. In this research, anaerobic biodegradation microcosm studies, which mimic the unsaturated zone of a LFG plume, are conducted using methanogenic soil samples. Results are discussed in terms of the potential effects on CFCs signatures due to anaerobic biodegradation in the unsaturated zone and will also explore ways of characterising NA processes by identifying the effects of diffusion on transport processes, and degradation products of CFCs. The discussion will also include how stable carbon isotopic signatures may be used to enhance our assessments of biodegradation of CFCs in the unsaturated zone around landfills.

Archbold, M.; Elliot, T. E.; Redeker, K.; Boshoff, G.

2003-04-01

12

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

Microsoft Academic Search

The composition of landfill gas (LFG) was analyzed for vapor-phase mercury (Hg) (primarily in its elemental form, Hg0) 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

Ki-Hyun Kim; Min-Young Kim

2002-01-01

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

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 ...

15

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

16

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

17

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

18

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...

19

Degradation of landfill gas constituents in soil  

SciTech Connect

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 landfill gas constituents in LFG affected soils, and to evaluate the importance of the degradation processes to the emission. High methane oxidation potentials were found in laboratory experiments at 25{degrees}C. The degradation seemed to follow a zero order reaction kinetics, and was 3-4 times slower at 10{degrees}C as compared to 25{degrees}C. Also high degradation rates for benzene and toluene were observed. In soils sampled away from the landfill where almost no LFG contamination had been observed, longer lag phases and lower degradation rates of the two aromatic hydrocarbons were observed. Slow cometabolic degradation of trichloroethylene (TCE) and 1,1,1-trichloroethane (TCA) was observed when methane was present in the batch experiments. The rates were much lower than the rates for the aromatic hydrocarbons. In the field at Skellingsted Landfill, Denmark high methane emissions were observed in an area just outside the landfill area, probably as a result of the clay landfill covering, which has led to significant lateral migration of LFG. Indications of active methane oxidation in the field were observed by measuring soil gas profiles. By comparison of the results obtained in the laboratory with the field results it is shown, that degradation processes may have a significant effect on the emission of all the compounds studied. However the subject needs much more attention.

Kjeldsen, P.; Dalager, A.; Broholm, K. [Technical Univ. of Denmark, Lyngby (Denmark)

1996-11-01

20

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...

21

Differentiating leachate effects from landfill gas effects at landfills  

SciTech Connect

Groundwater contamination at solid-waste management units is a major environmental concern in their operation. Volatile organic compounds (VOCs) have been proposed as valuable indicators of releases from these facilities. These are useful as indicator parameters in part because of the lack of detectable background concentrations in most cases, obviating the requirement of statistical evaluations to determine whether levels indicate a release from the landfill. However, detections of VOCs can arise from two different mechanisms--leachate releases and gas releases (Non-aqueous-phase liquid [NAPL] releases are not considered here). Differentiation between these two mechanisms for transport of VOCs to groundwater can allow for selection of the most appropriate corrective action technique.

Kerfoot, H.B.

1998-07-01

22

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

EPA Science Inventory

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

23

Methane Gas Utilization Project from Landfill at Ellery (NY)  

SciTech Connect

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

Pantelis K. Panteli

2012-01-10

24

Landfill gas pretreatment for fuel cell applications  

NASA Astrophysics Data System (ADS)

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

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

1994-04-01

25

DETERMINATION OF GUIDANCE VALUES FOR CLOSED LANDFILL GAS EMISSIONS  

E-print Network

of these parameters with on-site specific measurements enables the promotion of natural attenuation or active landfill management of landfill site with a residual organic compound fraction. The European risk assessment and riskDETERMINATION OF GUIDANCE VALUES FOR CLOSED LANDFILL GAS EMISSIONS O. BOUR*, S. BERGER**, C

Boyer, Edmond

26

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

27

LATERAL LANDFILL GAS MIGRATION: CHARACTERIZATION AND  

E-print Network

OF THE MIGRATION 2.1 Site description The landfill site was located in Malleville-sur-le Bec (Eure region, France, Figure 1) have appeared in the vicinity of the site. The landfill was then equipped with a LFG collection in the first years after the deposit of the waste. The study of a landfill site began in 2001

Boyer, Edmond

28

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

29

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

E-print Network

Materials Table A1: Model Results for West Lake Landfill WEST LAKE IC Engine Gas Turbine Steam Turbine Landfill WEST COUNTY IC Engine Gas Turbine Steam Turbine Average Landfill Gas Generation (mmcf/yr) 1,075 1,735 $1,250 Table A3: Model Results for Modern Landfill MODERN IC Engine Gas Turbine Steam Turbine Average

Jaramillo, Paulina

30

LANDFILL GAS AND THE GREENHOUSE EFFECT  

EPA Science Inventory

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

31

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

PubMed

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

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

2014-05-01

32

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...

33

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

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Landfill Gas Collection Efficiencies HH Table...PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste...Subpart HH of Part 98—Landfill Gas Collection Efficiencies...

2011-07-01

34

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

35

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

Microsoft Academic Search

A G3600 engine was developed to operate on landfill gas to demonstrate engine performance and identify any operational problems caused by this application. Fuel system and engine performance development were completed using simulated landfill gas containing carbon dioxide and natural gas at the Caterpillar Technical Center. The engine was packaged as a generator set and has operated for 12,000 hours

G. P. Mueller

1995-01-01

36

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...

37

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

Microsoft Academic Search

An examination of the effects of landfill gas production enhancement in a field-scale program is presented. The enhancement entailed the use of leachate recycling to promote more conducive environmental conditions for the anaerobic microorganisms so that they would grow more quickly and thus convert the organic fraction of the municipal solid waste to methane at a faster rate. Seven field-scale

G. DiPippo; A. P. Leuschner

1987-01-01

38

Groundwater impacts associated with landfill gas migration at municipal solid waste landfill sites  

SciTech Connect

Many older municipal solid waste (MSW) landfills are unlined and subsequently have become a source of local groundwater contamination. However, the adverse impact on the groundwater quality at such sites is not necessarily limited to that caused by leachate contamination of the underlying aquifer but also may include the effects of landfill gas (LFG) migration. Absorption of certain LFG components, particularly volatile organic compounds (VOCs), may occur at offsite locations when a LFG excursion front migrates into adjacent soils. When LFG management systems are installed at such sites, this problem is often eliminated.

Clister, W.; Janechek, A.; Hibbs, S.

1998-07-01

39

Model to aid the design of composite landfill liners  

E-print Network

MODEL TO AID THE DESI(iN OF COMPOSITE LANDFILL LINERS A Thesis by KIFAYATHULLA MOHAMMED Submitted to the School of Graduate Studies Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1993... Major Subject: Safety Engineering MODEL TO AID THE DESIGN OF COMPOSITE LANDFILL LINERS A Thesis by Kifayathulla Mohammed Approved as to style and content by: Kevin J. Mclnnes (Co-chairman of Committee) Richard P. Kon n (Member John P. Wagner...

Mohammed, Kifayathulla

1993-01-01

40

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

SciTech Connect

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

DiPippo, G.; Leuschner, A.P.

1987-07-01

41

LCA and economic evaluation of landfill leachate and gas technologies.  

PubMed

Landfills receiving a mix of waste, including organics, have developed dramatically over the last 3-4 decades; from open dumps to engineered facilities with extensive controls on leachate and gas. The conventional municipal landfill will in most climates produce a highly contaminated leachate and a significant amount of landfill gas. Leachate controls may include bottom liners and leachate collection systems as well as leachate treatment prior to discharge to surface water. Gas controls may include oxidizing top covers, gas collection systems with flares or gas utilization systems for production of electricity and heat. The importance of leachate and gas control measures in reducing the overall environmental impact from a conventional landfill was assessed by life-cycle-assessment (LCA). The direct cost for the measures were also estimated providing a basis for assessing which measures are the most cost-effective in reducing the impact from a conventional landfill. This was done by modeling landfills ranging from a simple open dump to highly engineered conventional landfills with energy recovery in form of heat or electricity. The modeling was done in the waste LCA model EASEWASTE. The results showed drastic improvements for most impact categories. Global warming went from an impact of 0.1 person equivalent (PE) for the dump to -0.05 PE for the best design. Similar improvements were found for photochemical ozone formation (0.02 PE to 0.002 PE) and stratospheric ozone formation (0.04 PE to 0.001 PE). For the toxic and spoiled groundwater impact categories the trend is not as clear. The reason for this was that the load to the environment shifted as more technologies were used. For the dump landfill the main impacts were impacts for spoiled groundwater due to lack of leachate collection, 2.3 PE down to 0.4 PE when leachate is collected. However, at the same time, leachate collection causes a slight increase in eco-toxicity and human toxicity via water (0.007 E to 0.013 PE and 0.002 to 0.003 PE respectively). The reason for this is that even if the leachate is treated, slight amounts of contaminants are released through emissions of treated wastewater to surface waters. The largest environmental improvement with regard to the direct cost of the landfill was the capping and leachate treatment system. The capping, though very cheap to establish, gave a huge benefit in lowered impacts, the leachate collection system though expensive gave large benefits as well. The other gas measures were found to give further improvements, for a minor increase in cost. PMID:21435856

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

2011-07-01

42

Landfill methane recovery. Part II: gas characterization. Final report, December 1981December 1982  

Microsoft Academic Search

This study addresses field sampling, analytical testing, and data generation for the characterization of both raw and processed landfill gas. Standardized protocols were developed for the sampling and analysis of the landfill gas for trace constituents and are presented as Appendices A-C. A nationwide survey was conducted in which gas samples were collected at nine landfill sites and tested for

G. R. Lytwynyshyn; R. E. Zimmerman; N. W. Flynn; R. Wingender; V. Olivieri

1982-01-01

43

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Landfill Gas Collection Efficiencies HH Table HH-3...PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills...HH-3 to Subpart HH of Part 98—Landfill Gas Collection Efficiencies Description...

2013-07-01

44

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Landfill Gas Collection Efficiencies HH Table HH-3...PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills...HH-3 to Subpart HH of Part 98—Landfill Gas Collection Efficiencies Description...

2012-07-01

45

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

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Landfill Gas Collection Efficiencies HH Table HH-3...PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills...HH-3 to Subpart HH of Part 98—Landfill Gas Collection Efficiencies Description...

2014-07-01

46

Occurrence and origin of phosphine in landfill gas.  

PubMed

A landfill (Hooge Maey, Flanders, Belgium) was subjected to an in-depth study in order to explain the origin of phosphine detected in high amounts in landfill gas, in comparison with biogas from other sources, during a previous study. The spatial and temporal variability of the phosphine concentration in landfill gas was assessed. Twenty-four wells were monitored and differences in phosphine concentration up to one log unit were observed (3.2-32.4 microg/m(3)). The phosphine concentration in each well was constant in time over a period of 4 months. No correlation was found between the phosphine concentration and methane, carbon dioxide, hydrogen sulfide, ethene or ethane concentration. In a series of laboratory tests, it was shown that phosphine was emitted during batch fermentation tests inoculated with landfill leachate when Fe(0) or Al(0) specimens were added. Conditions favouring corrosion of iron gave rise to higher emissions of phosphine. The phosphine concentration in the headspace of a batch test rose to 1.43 mg/m(3) after 27 days of incubation. Weight loss of corroding steel coupons correlated with phosphine emission. Calculations showed that all phosphine emitted from the 0.005 km(3) landfill (160 g/year) could be attributed to corrosion of metals. No evidence of de novo synthesis could be established. PMID:15172581

Roels, Joris; Verstraete, Willy

2004-07-01

47

Establishing landfill gas as a cause of groundwater contamination  

SciTech Connect

The purpose of this paper is to describe some of the tell-tale characteristics of contaminant transport via landfill gas migration and corresponding investigative techniques that can be used to identify when this is occurring. Some fundamental principles are presented that can be used to distinguish between groundwater contamination through gas phase (landfill gas) vs. liquid phase (leachate) migration. Then, specific techniques are presented, based on these principles, that have been used in field investigations to determine whether gas phase or liquid phase contaminant pathways predominate. These are combined into an overall strategy that can be used to evaluate and identify the extent and direction of a gas-phase vadose zone contaminant pathway. Finally, a detailed case study is presented that uses some of the principles and techniques cited.

Kraemer, T.A.; Carpenter, M.; Hartley, J.

1998-07-01

48

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 ...

49

Landfill gas utilization at a waste water treatment plant  

Microsoft Academic Search

The Central Contra Costa Sanitary District (CCCSD) in Contra Costa County, California, has been using landfill gas (LFG) as a major source of energy in its wastewater treatment plant for approximately one and half years. A discussion of the CCCSD LFG project is presented, including its origin, highlights of the initial feasibility study, the design of the selected LFG alternative,

C. L. Weddle; H. S. McDonald; W. R. Howard

1983-01-01

50

ANALYSIS OF FACTORS AFFECTING METHANE GAS RECOVERY FROM SIX LANDFILLS  

EPA Science Inventory

The report gives results of a pilot study of six U.S. landfills that have methane (CH4) gas recovery systems. NOTE: The study was a first step in developing a field testing program to gather data to identify key variables that affect CH4 generation and to develop an empirical mod...

51

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...

52

LANDFILL GAS UTILIZATION - DATABASE OF NORTH AMERICAN PROJECTS  

EPA Science Inventory

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

53

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...

54

The landfill gas activity of the IEA bioenergy agreement  

Microsoft Academic Search

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

A Lagerkvist

1995-01-01

55

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

SciTech Connect

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

None

1983-09-01

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

Landfill siloxane gas sensing using differentiating, responsive phase coated microcantilever arrays.  

PubMed

Landfill biogases are being utilized more frequently as a new source of fuel energy. Volatile siloxane compounds usually contained in landfill biogases will form siloxane residues when the gases are burned, which significantly increases abrasion of combustion engines. Research on detection of siloxanes in landfill gas has been active during recent years with the principal analytical technique being gas chromatography/mass spectrometry (GC/MS). In our present work, we introduce a less expensive, compact methodology that employs microcantilever (MC) arrays for sensitive nanomechanical-based gas-phase sensing of the siloxanes. The cantilevers on the MC array were differentially coated on the active, nanostructured side with different responsive phases, and composite responses (magnitude of siloxane-induced MC bending) for four siloxanes were collected that exhibited selective signatures to aid in recognizing each siloxane. Limits of detection (LODs) derived from linear calibration plots were down to the sub-parts-per-million range, a sensitivity that is comparable with that of GC/MS reported by other researchers. Studies were performed in rather inert helium environment and a realistic matrix, and the overall response profiles and LODs were similar for both matrixes. A 5 week long-term reproducibility study illustrates the stability of the MC array. Moreover, the portable character of the MC array setup makes our method a very promising way to facilitate in-field detection of siloxanes in landfill gas in the future. PMID:19267478

Long, Zhou; Storey, John; Lewis, Samuel; Sepaniak, Michael J

2009-04-01

58

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

PubMed

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

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

2008-01-01

59

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

PubMed

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

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

2008-04-01

60

GAS CHARACTERIZATION, MICROBIOLOGICAL ANALYSIS, AND DISPOSAL OF REFUSE IN GRI (GAS RESEARCH INSTITUTE) LANDFILL SIMULATORS  

EPA Science Inventory

The report describes the termination of a five-year pilot-scale project that evaluated methane production and gas enhancement techniques in sanitary landfills. Sixteen simulated landfills were constructed in 1980 and operated until January 1985. Data collected during this termina...

61

Chemical characterization of odorous gases at a landfill site by gas chromatography–mass spectrometry  

Microsoft Academic Search

The composition of odorous gases emitted from a municipal landfill in the city of Izmir, Turkey was investigated using gas chromatography–mass spectrometry, and these data were examined in relation with the odor concentrations. Several volatile organic compounds (VOCs) were identified and quantified at five sampling sites in May and September 2005. Detected VOCs were monoaromatics (0.09–47.42?gm?3), halogenated compounds (0.001–62.91?gm?3), aldehydes

Faruk Dincer; Mustafa Odabasi; Aysen Muezzinoglu

2006-01-01

62

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

PubMed

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

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

2011-05-01

63

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

64

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

65

Remote real-time monitoring of subsurface landfill gas migration.  

PubMed

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

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

2011-01-01

66

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

67

Landfill gas recovery: should your community consider it  

SciTech Connect

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

Shuput, T.A.

1985-08-01

68

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

PubMed

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

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

2008-05-01

69

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

PubMed

Field experiments investigating lateral gas transport in soil adjacent to an old landfill in Denmark during a one-year period were conducted. A significant seasonal variation, with low concentrations of methane and high concentrations of carbon dioxide in the summer, caused by methane oxidation was observed. There was a good correlation between pressure above the barometric pressure and the methane concentration in the soil, indicating that advective flow was the controlling process. This was confirmed by calculations. Diurnal measurement during a drop in barometric pressure showed that lateral migration of landfill gas was a very dynamic system and the concentrations of LFG at a specific place and depth changed dramatically within a very short time. The experiments showed that change in barometric pressure was an important factor affecting gas migration at the Skellingsted landfill in Denmark. PMID:11721997

Christophersen, M; Kjeldsen, P

2001-04-01

70

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

PubMed

Field experiments investigating lateral gas transport in soil adjacent to an old landfill in Denmark during a one-year period were conducted. A significant seasonal variation, with low concentrations of methane and high concentrations of carbon dioxide in the summer, caused by methane oxidation was observed. There was a good correlation between pressure above the barometric pressure and the methane concentration in the soil, indicating that advective flow was the controlling process. This was confirmed by calculations. Diurnal measurement during a drop in barometric pressure showed that lateral migration of landfill gas was a very dynamic system and the concentrations of LFG at a specific place and depth changed dramatically within a very short time. The experiments showed that change in barometric pressure was an important factor affecting gas migration at the Skellingsted landfill in Denmark. PMID:12201689

Christophersen, M; Kjeldsen, P

2001-12-01

71

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...

72

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

PubMed

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

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

2014-07-01

73

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

74

LANDFILL GAS AND ITS INFLUENCE ON GLOBAL CLIMATE CHANGE  

EPA Science Inventory

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

75

Suitability of Tedlar ® gas sampling bags for siloxane quantification in landfill gas  

Microsoft Academic Search

Landfill or digester gas can contain man-made volatile methylsiloxanes (VMS), usually in the range of a few milligrams per normal cubic metre (Nm3). Until now, no standard method for siloxane quantification exists and there is controversy with respect to which sampling procedure is most suitable. This paper presents an analytical and a sampling procedure for the quantification of common VMS

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

2010-01-01

76

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...

77

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

78

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

SciTech Connect

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

K. David Newell; Timothy R. Carr

2007-03-31

79

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...

80

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

PubMed

This paper examines landfill gas (LFG) emissions at a large inactive waste disposal site to evaluate the viability of investment in LFG recovery through the clean development mechanism (CDM) initiative. For this purpose, field measurements of LFG emissions were conducted and the data were processed by geospatial interpolation to estimate an equivalent site emission rate which was used to calibrate and apply two LFG prediction models to forecast LFG emissions at the site. The mean CH(4) flux values calculated through tessellation, inverse distance weighing and kriging were 0.188±0.014, 0.224±0.012 and 0.237±0.008 l CH(4)/m(2) hr, respectively, compared to an arithmetic mean of 0.24 l/m(2) hr. The flux values are within the reported range for closed landfills (0.06-0.89 l/m(2) hr), and lower than the reported range for active landfills (0.42-2.46 l/m(2) hr). Simulation results matched field measurements for low methane generation potential (L(0)) values in the range of 19.8-102.6 m(3)/ton of waste. LFG generation dropped rapidly to half its peak level only 4 yrs after landfill closure limiting the sustainability of LFG recovery systems in similar contexts and raising into doubt promoted CDM initiatives for similar waste. PMID:22265005

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

2012-11-01

81

Landfill Methane  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

82

LANDFILL GAS EMISSIONS FROM LANDFILLS IN SANTIAGO DE CHILE - STRATEGIES TO REDUCE IMPACT ON LOCAL ENVIRONMENT AS WELL AS ON GLOBAL CLIMATE  

Microsoft Academic Search

Treatment of MSW in Santiago de Chile is limited mostly to final disposal at landfills, without any previous biological or thermal treatment, nor any recovery of biomass. Due to the decomposition of the organic fraction of MSW leachate is produced, as well as landfill gas, which contributes to global warming, local air pollution, odour and nuisance and increases the risk

J. Vogdt

83

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

SciTech Connect

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

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

2012-02-15

84

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

NASA Astrophysics Data System (ADS)

Landfill gas is a significant contributor to anthropogenic emissions of CH4 and CO2. The U.S. Environmental Protection Agency has estimated the total U.S. 2007 emissions of the CH4 component of landfill gas at 132.9 Tg CO2 Equivalent. This compares to total CH4 emission from all US sources in 2007 at 585.3 Tg CO2 Equivalent. Worldwide CH4 emissions from landfill gas have been estimated at 668 Tg CO2 Equivalent. Satellite remote sensing can also be used to characterize landfill gas emissions. The NASA Orbiting Carbon Observatory (OCO-2) and the proposed CarbonSAT (University of Bremen) satellites are particularly suited for this purpose. The Orbiting Carbon Observatory (OCO) was designed to provided high spatial resolution ( < 3 km2 footprints) and high accuracy ( 0.5 to 3 ppm) CO2 measurements. The original OCO satellite failed to achieve orbit in February 2009. A replacement satellite (OCO-2) is under construction and scheduled for launch in February 2013. These characteristics will allow the measurement of CO2 emissions from large landfills on the orbit path. Because surface landfill gas emissions include both CH4 and CO2 , the CH4 concentration can be inferred from CO2 concentrations. The CarbonSAT satellite which is being designed by the University of Bremen, Institute for Environmental Physics, has similar characteristics to OCO-2 but it has been optimized for measurement of both CH4 and CO2 . Key specifications for the CarbonSAT satellite include XCO2 single measurement error of < 1 to 3 ppm and XCH4 single measurement error of < 10 to 18 ppb. These characteristics will make it possible to detect both CO2 and CH4 emissions from large landfills. The spatial resolution and accuracy of the CO2 measurements from OCO-2 and CO2 and CH4 measurements from CarbonSAT present a unique opportunity to measure landfill gas emissions from large landfills such as exist in the United States and other developed countries. In general, landfills in the developed countries have landfill gas control system ground based landfill gas monitoring systems. These ground-based measurements can be used to calibrate OCO-2 and CarbonSAT landfill gas measurements. OCO-2 and CarbonSAT can be used to measure landfill emissions from the large landfills and open dumps of the emerging megacities in the developing world where accurate ground measurements are not available. For example Mexico City generates 26,000 MT of municipal solid waste that is disposed of in two uncontrolled landfills. Similar conditions exist in Asia, Latin America, and Africa. Satellite based measurements of these landfill gas emissions could help prioritize greenhouse gas remediation projects for these countries.

Vigil, S. A.; Bovensmann, H.

2010-12-01

85

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

86

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

SciTech Connect

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

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

2012-11-15

87

Gas-composition tester  

Microsoft Academic Search

This paper describes a device for testing the gas composition that measures the percent composition of air in the Freon. The instrument operates by recording the variation of the value of a capacitor when the dielectric constant of the gas mixture between its places is changed. The device consists of a unit with capacitors, a circuit for measuring capacitance difference,

V. V. Karpukhin; A. V. Kulikov; S. V. Trusov

1986-01-01

88

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

89

[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

90

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

EPA Science Inventory

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

91

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

92

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

Microsoft Academic Search

In the long-term, landfills are producing landfill gas (LFG) with low calorific values. Therefore, the utilization of LFG in combined heat and power plants (CHP) is limited to a certain period of time. A feasible method for LFG treatment is microbial CH4 oxidation. Different materials were tested in actively aerated lab-scale bio-filter systems with a volume of 0.167m3. The required

R. Haubrichs; R. Widmann

2006-01-01

93

Landfill gas: resource evaluation and development. Final report, August-July, 1985  

Microsoft Academic Search

The study developed a document that will assist utilities, municipalities, and other interested parties in evaluating the potential for using landfill-gas (LFG) resources. The LFG workbook describes the state-of-the-art methodology for energy recovery from landfill sites, and the techniques used to evaluate the feasibility of a potential project. The document provides the reader with background in a number of areas.

R. E. Zimmerman; J. J. Walsh; M. Wilkey

1985-01-01

94

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 MWh’s of clean energy o By destroying the methane in the landfill gas, the Project will generate CO2 equivalent reductions of 164,938 tons annually. The completed facility produces 27.4 MWnet and operates 24 hours a day, seven days a week.

Galowitz, Stephen

2012-12-31

95

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

SciTech Connect

The primary objective of the Project was to maximize the productive use of the substantial quantities of waste landfill gas generated and collected at the Central Landfill in Johnston, Rhode Island. An extensive analysis was conducted and it was determined that utilization of the waste gas for power generation in a combustion turbine combined cycle facility was the highest and best use. The resulting project reflected a cost effective balance of the following specific sub-objectives. 1) Meet environmental and regulatory requirements, particularly the compliance obligations imposed on the landfill to collect, process and destroy landfill gas. 2) Utilize proven and reliable technology and equipment. 3) Maximize electrical efficiency. 4) Maximize electric generating capacity, consistent with the anticipated quantities of landfill gas generated and collected at the Central Landfill. 5) Maximize equipment uptime. 6) Minimize water consumption. 7) Minimize post-combustion emissions. To achieve the Project Objective the project consisted of several components. 1) The landfill gas collection system was modified and upgraded. 2) A State-of-the Art gas clean up and compression facility was constructed. 3) A high pressure pipeline was constructed to convey cleaned landfill gas from the clean-up and compression facility to the power plant. 4) A combined cycle electric generating facility was constructed consisting of combustion turbine generator sets, heat recovery steam generators and a steam turbine. 5) The voltage of the electricity produced was increased at a newly constructed transformer/substation and the electricity was delivered to the local transmission system. The Project produced a myriad of beneficial impacts. 1) The Project created 453 FTE construction and manufacturing jobs and 25 FTE permanent jobs associated with the operation and maintenance of the plant and equipment. 2) By combining state-of-the-art gas clean up systems with post combustion emissions control systems, the Project established new national standards for best available control technology (BACT). 3) The Project will annually produce 365,292 MWh?s of clean energy. 4) By destroying the methane in the landfill gas, the Project will generate CO{sub 2} equivalent reductions of 164,938 tons annually. The completed facility produces 28.3 MWnet and operates 24 hours a day, seven days a week.

Galowitz, Stephen

2013-06-30

96

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

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. Work was done in the following areas: (1) production of natural gas pipeline methane for liquefaction at an existing LNG facility, (2) production of LNG from sewage digester gas, (3) the use of mixed refrigerants for process cooling in the production of LNG, liquid CO{sub 2} and pipeline methane, (4) cost estimates for an LNG production facility at the Arden Landfill in Washington PA.

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

2000-10-20

97

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

NASA Astrophysics Data System (ADS)

Landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric methane (CH4). Until recently, landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest sources of anthropogenic CH4 emission, the final cover system should also be designed for minimizing the greenhouse gases migration into the atmosphere or the areas surrounding the landfill while securing the hydraulic performance. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil, few studies about gas transport characteristics of landfill cover soils have been done. However, recent soil-gas studies implied that the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size are key parameters to understand landfill gaseous performance. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport. In this study, the effects of compaction level and particle size fraction effects on ka and Dp for landfill final cover soil was investigated. The disturbed soil samples were taken from landfill final cover in Japan. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm, 2120 cm3) at two different compaction levels [(MP):2700 kN/m2 and (SP):600 kN/m2]. After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential of 0.98, 2.94, 9.81, 1235 kPa and with air-dried and oven-dried conditions. Results showed that measured Dp and ka values for the coarser (< 35 mm) fraction became larger than finer (< 2 mm) for the given soil-air content. Further, compaction effort was much significant for ka than Dp for both fractions. We suggest this is because of compaction effects caused to create well-aligned macropore networks that are available for gas transport through the porous material. Then, the famous predictive models, the water induced linear reduction (WLR) model for Dp and the reference point law (RPL) model for ka were modified with reference point measurements (dry conditions) and model parameters and they correlated linearly to dry bulk density values for both fractions of landfill final cover soil.

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

2011-12-01

98

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...

99

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...

100

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

NASA Astrophysics Data System (ADS)

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

Reshetyuk, Yuriy; Mårtensson, Stig-Göran

2014-04-01

101

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

102

Gas-composition tester  

SciTech Connect

This paper describes a device for testing the gas composition that measures the percent composition of air in the Freon. The instrument operates by recording the variation of the value of a capacitor when the dielectric constant of the gas mixture between its places is changed. The device consists of a unit with capacitors, a circuit for measuring capacitance difference, and a gas system. The accuracy of measurement of Freon concentration, which is 0.3% under normal conditions, corresponds to an accuracy of determination of the relative variation of the refractive index of 7 X 10/sup -6/. The described device can also be used to determine the percent composition of other two-component gas mixtures with different refractive indices.

Karpukhin, V.V.; Kulikov, A.V.; Trusov, S.V.

1986-06-01

103

Gas migration and vent design at landfill sites  

Microsoft Academic Search

A finite element model has been developed to simulate the migration of gases in soil from a buried source such as a landfill. Using quadratic elements, the diffusion convection equation coupled with the mass conservation equation of a binary mixture of gases is solved under a combination of Dirichlet, Neumann and flux type of boundary conditions. The model is compared

M. F. N. Mohsen; G. J. Farquhar; N. Kouwen

1980-01-01

104

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

EPA Science Inventory

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

105

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

Microsoft Academic Search

Many developed countries have targeted landfill methane recovery among greenhouse gas mitigation strategies, since methane is the second most important greenhouse gas after carbon dioxide. Major questions remain with respect to actual methane production rates in field settings and the relative mass of methane that is recovered, emitted, oxidized by methanotrophic bacteria, laterally migrated, or temporarily stored within the landfill

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

2006-01-01

106

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

NASA Astrophysics Data System (ADS)

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

2000-05-01

107

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

108

DATABASE OF LANDFILL GAS TO ENERGY PROJECTS IN THE UNITED STATES  

EPA Science Inventory

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

109

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

EPA Science Inventory

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

110

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

Microsoft Academic Search

The pretreatment of the biodegradable components of municipal solid waste (MSW) has been suggested as a method of reducing landfill gas emissions. Mechanical biological treatment (MBT) is the technology being developed to provide this reduction in biodegradability, either as an alternative to source segregated collection or for dealing with residual MSW which still contains high levels of biodegradable waste. The

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

2010-01-01

111

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...

112

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...

113

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

EPA Science Inventory

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

114

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...

115

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

116

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

PubMed

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

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

2014-09-01

117

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

Microsoft Academic Search

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

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

2008-01-01

118

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

119

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

Microsoft Academic Search

Mechanical biological treatment (MBT) of residual municipal solid waste (RMSW) was investigated with respect to landfill gas generation. Mechanically treated RMSW was sampled at a full-scale plant and aerobically stabilized for 8 and 15 weeks. Anaerobic tests were performed on the aerobically treated waste (MBTW) in order to estimate the gas generation rate constants (k,y?1), the potential gas generation capacity

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

2009-01-01

120

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 (641-998 kg CO2-eq·t(-1)ww) than those from open dump (Scenario 0, 480-734 kg CO2-eq·t(-1)ww). This was due to the strictly anaerobic conditions in Scenario 1. LFG collection and treatment reduced GHG emissions to 448-684 kg CO2-eq·t(-1)ww in Scenario 2 (with LFG flare) and 214-277 kg CO2-eq·t(-1)ww in Scenario 3 (using LFG for electricity production). Amongst the seven categories, FM was the predominant contributor to GHG emissions. Global sensitivity analysis demonstrated that the parameters associated with waste characteristics (i.e. CH4 potential and carbon sequestered faction) and LFG management (i.e. LFG collection efficiency and CH4 oxidation efficiency) were of great importance. A further learning on the MSW in China indicated that water content and dry matter content of food waste were the basic factors affecting GHG emissions. Source separation of food waste, as well as increasing the incineration ratio of mixed collected MSW, could effectively mitigate the overall GHG emissions from landfilling in a specific city. To increase the LFG collection and CH4 oxidation efficiencies could considerably reduce GHG emissions on the landfill site level. While, the improvement in the LFG utilization measures had an insignificant impact as long as the LFG is recovered for energy generation. PMID:24018116

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

2013-11-15

121

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...

122

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

123

Kaolinite sorption of Cd, Ni and Cu from landfill leachates: influence of leachate composition.  

PubMed

Heavy metal speciation in landfill leachates plays a significant role in determining the mobility during the percolation through soils. The complexation characteristics of landfill leachate directly affects heavy metal solubility and the extent of the interaction with soils, lowering or raising the sorbed amount depending on the relative affinity of the complexed metal and uncomplexed form to soil adsorption sites. In this paper, the adsorption of Cd, Ni and Cu onto kaolinite from three leachates (collected from landfill at different fermentation stage) is studied, also in comparison with metal speciation by two different operative procedures. The heavy metals, at their natural concentration, were divided into operational classes according to an exchange-based procedure and by fractionation on the basis of molecular weight (exchange onto Chelex100 resin and ultrafiltration, respectively). All the experiments were performed also on synthetic solutions designed according to leachate composition and theoretical speciation. The experimental results have shown leachate complexing capacity is strongly dependent on landfill age, and that broad parameters such as COD, DOC, pH, ionic strength and VFA concentration are not able to predict it. It is notheworthy that the strong complexing capacity of leachate can cause extraction of metals from the solid phase instead of adsorption from the liquid one. PMID:11548004

Petrangeli Papini, M; Majone, M; Rolle, E

2001-01-01

124

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

EPA Science Inventory

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

125

SALE OF SURPLUS DIGESTER AND LANDFILL GAS TO PUBLIC UTILITIES  

EPA Science Inventory

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

126

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

127

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

128

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

129

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

SciTech Connect

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

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

2010-09-30

130

Comparision of two different ways of landfill gas utilization through greenhouse gas emission reductions analysis and financial analysis.  

PubMed

Greenhouse gas (GHG) emission reductions and utilization of landfill gas (LFG) were researched by comparing LFG displacing the use of natural gas (scenario 2) with electricity generation using LFG (scenario 3) at three different LFG collecting efficiencies; 35, 50 and 65%. The results show that the utilization of LFG in scenario 2 is 1.4 times that in scenario 3. GHG emission reductions generated by scenario 2 are slightly less than that of scenario 3. The GHG emission reductions and utilization of LFG are restricted by LFG collecting efficiencies. It will be helpful to improve the management level of landfill and the GHG emissions reduction by introducing the CDM. However, the utilization of LFG will be still short of financial attractiveness if the LFG collection efficiency is less than 50%. PMID:19767323

Han, Haibin; Qian, Guangren; Long, Jisheng; Li, Shude

2009-11-01

131

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

Microsoft Academic Search

Seven pilot-scale partitioning gas tracer tests (PGTTs) were conducted to assess the accuracy and reproducibility of this method for measuring water in municipal solid waste landfills. Tests were conducted in the same location over a 12-month period, and measured moisture conditions ranged from possible dry waste to refuse with a moisture content of 24.7%. The final moisture content of 24.7%

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

2006-01-01

132

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

133

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

134

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

PubMed

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

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

2009-09-01

135

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

136

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

SciTech Connect

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

Nam, Sangchul; Namkoong, Wan [Department of Environmental Engineering, Konkuk University, Hwayang-Dong, Gwangjin-Gu, Seoul 143-701 (Korea, Republic of); Kang, Jeong-Hee; Park, Jin-Kyu [Department of Environmental Engineering, Anyang University, Anyang 5-Dong, Manan-Gu, Anyang-Si, Gyeonggi-Do 430-714 (Korea, Republic of); Lee, Namhoon, E-mail: nhlee@anyang.ac.kr [Department of Environmental Engineering, Anyang University, Anyang 5-Dong, Manan-Gu, Anyang-Si, Gyeonggi-Do 430-714 (Korea, Republic of)

2013-10-15

137

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

PubMed

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

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

2013-03-01

138

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

NASA Astrophysics Data System (ADS)

There are 39 cities composing the Metropolitan Area of São Paulo (MASP) which has grown seven times during the last sixty years, reaching, in 2011, 19.3 million inhabitants. This fact associated with a strong industrial development provoked, among other consequences, a disordered urbanization along the most important river of the region: Tietê. About 100 Km of its 1,150 Km full extension crosses MASP and, during the 60's, Marginal Tietê roadway was constructed, occupying the river banks as access routes. Tietê River was straightened and several landfills were created with its deposit (sediment and mud). EACH-USP (46.50 W, 23.48 S) lies nowadays in one of these areas, where this work has been developed. Therefore, the goal is to evaluate the chemical composition (ionic and gases) and its variability in function of the depth levels using three wells, from 0.60 to 9.0 m of depth. The wells were perforated in September 2011, end of the dry weather. Each well owns a homemade multiport sampling device (HMSD), being possible to push gas and/or water up from 15 available ports. The gases measurements were carried out using a GEM-2000 plus (Landtec) portable analyzer. Aqueous samples containing solid material were taken at each level depth from ports of the HMSD. However, no water was found in some levels. All samples were kept cooled until analysis procedures. After decantation of the solid material, the supernatant liquid was divided in two portions, being its conductivity (Micronal conductimeter) and pH (pH-meter Metrohm 654 with combined glass electrode) measured with the former and ionic analysis with the latter, in which all samples were filtered (Millex 0.22 micrometer pores) before each ionic chromatographic analysis, using Metrohm 850 System, for the ions: sodium, ammonium, potassium, calcium, magnesium, chloride, nitrate and sulfate. The first sampling stage was carried out during November and December 2011 in the beginning of rainy season in the mid Spring. From all the analysis performed, a large variability of the results may be observed for both gases and ionic composition not only among the wells, but also among the different depth levels. Vertically, one of the wells (W2) showed the same percentage of gases, methane 55% and carbon dioxide 45%, at all depth levels, while the other two wells (W1 and W3) presented these gases percentages only under 5.0 m deep. Concerning oxygen, 25% of this gas was detected at 1.0 m under the surface in W1 and W3. In relation to aqueous samples, the most acidity was observed near the surface (0.60 m deep, W1), pH 4.65, while pH 7.88 was obtained under 5.0 m deep (W3). For ionic concentrations a large range was observed considering all wells, being the lowest values for sulfate, from 0.60 to 20 mg/l, and the highest values for ammonium, between 14 and 53 mg/l. These results variability can be associated to the different soil composition layers, as well as to the biodegradation process and the time confinement of the river material deposit.

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

2012-04-01

139

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

140

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

141

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

USGS Publications Warehouse

Assessments of contaminants in soil gas were conducted in two study areas at Fort Gordon, Georgia, in July and August of 2011 to supplement environmental contaminant data for previous studies at the 17th Street landfill. The two study areas include northern and eastern parts of the 17th Street landfill and the adjacent wooded areas to the north and east of the landfill. These study areas were chosen because of their close proximity to the surface water in Wilkerson Lake and McCoys Creek. A total of 48 soil-gas samplers were deployed for the July 28 to August 3, 2011, assessment in the eastern study area. The assessment mostly identified detections of total petroleum hydrocarbons (TPH), and gasoline- and diesel-range compounds, but also identified the presence of chlorinated solvents in six samplers, chloroform in three samplers, 2-methyl naphthalene in one sampler, and trimethylbenzene in one sampler. The TPH masses exceeded 0.02 microgram (?g) in all 48 samplers and exceeded 0.9 ?g in 24 samplers. Undecane, one of the three diesel-range compounds used to calculate the combined mass for diesel-range compounds, was detected in 17 samplers and is the second most commonly detected compound in the eastern study area, exceeded only by the number of TPH detections. Six samplers had detections of toluene, but other gasoline compounds were detected with toluene in three of the samplers, including detections of ethylbenzene, meta- and para-xylene, and octane. All detections of chlorinated organic compounds had soil-gas masses equal to or less than 0.08 ?g, including three detections of trichloroethene, three detections of perchloroethene, three chloroform detections, one 1,4-dichlorobenzene detection, and one 1,1,2-trichloroethane detection. Three methylated compounds were detected in the eastern study area, but were detected at or below method detection levels. A total of 32 soil-gas samplers were deployed for the August 11–24, 2011, assessment in the northern study area. All samplers in the survey had detections of TPH, but only eight of the samplers had detections of TPH greater than 0.9 mg. Four samplers had TPH detections greater than 9 mg; the only other fuel-related compounds detected in these four samplers included toluene in three of the samplers and undecane in the fourth sampler. Three samplers deployed along the western margin of the northern landfill had detections of both diesel-and gasoline-related compounds; however, the diesel-related compounds were detected at or below method detection levels. Seven samplers in the northern study area had detections of chlorinated compounds, including three perchloroethene detections, three chloroform detections, and one 1,4-dichloro-benzene detection. One sampler on the western margin of the landfill had detections of 1,2,4-trimethylbenzene and 1,3,5-tr-methylbenene below method detection levels.

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

2012-01-01

142

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

143

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...

144

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

145

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

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

146

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

PubMed

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

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

2006-01-01

147

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

SciTech Connect

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

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

2006-07-01

148

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

149

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

150

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

151

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

152

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

PubMed

Vertically aligned carbon nanotube (CNT) layers were synthesized on Fe-coated low-cost alumina substrates using radio-frequency plasma enhanced chemical vapour deposition (RF-PECVD) technology. A miniaturized CNT-based gas sensor array was developed for monitoring landfill gas (LFG) at a temperature of 150 degrees C. The sensor array was composed of 4 sensing elements with unmodified CNT, and CNT loaded with 5 nm nominally thick sputtered nanoclusters of platinum (Pt), ruthenium (Ru) and silver (Ag). Chemical analysis of multicomponent gas mixtures constituted of CO(2), CH(4), H(2), NH(3), CO and NO(2) has been performed by the array sensor responses and pattern recognition based on principal component analysis (PCA). The PCA results demonstrate that the metal-decorated and vertically aligned CNT sensor array is able to discriminate the NO(2) presence in the multicomponent mixture LFG. The NO(2) gas detection in the mixture LFG was proved to be very sensitive, e.g.: the CNT:Ru sensor shows a relative change in the resistance of 1.50% and 0.55% for NO(2) concentrations of 3.3 ppm and 330 ppb dispersed in the LFG, respectively, with a wide NO(2) gas concentration range measured from 0.33 to 3.3 ppm, at the sensor temperature of 150 degrees C. The morphology and structure of the CNT networks have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. A forest-like nanostructure of vertically aligned CNT bundles in the multi-walled form appeared with a height of about 10 microm and a single-tube diameter varying in the range of 5-35 nm. The intensity ratio of the Raman spectroscopy D-peak and G-peak indicates the presence of disorder and defects in the CNT networks. The size of the metal (Pt, Ru, Ag) nanoclusters decorating the CNT top surface varies in the range of 5-50 nm. Functional characterization based on electrical charge transfer sensing mechanisms in the metal-modified CNT-chemoresistor array demonstrates high sensitivity by providing minimal sub-ppm level detection, e.g., download up to 100 ppb NO(2), at the sensor temperature of 150 degrees 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 degrees C. A comparison of the NO(2) 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. PMID:20154374

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

2010-03-12

153

BIOREACTOR LANDFILL DESIGN  

EPA Science Inventory

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

154

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

155

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

SciTech Connect

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

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

2010-06-30

156

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

157

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

158

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

159

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...

160

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

Code of Federal Regulations, 2010 CFR

...site-specific factors involved with landfill gas system design, alternative...control system that captures the gas generated within the landfill as required by paragraphs...as the control device, the landfill gas stream shall be...

2010-07-01

161

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

PubMed

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, ?(b), and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D(p)/D(o), ratio of gas diffusion coefficients in soil and free air) and air permeability (k(a)) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting ?(b) values ranging from 1.40 to 2.10 g cm(-3). Results showed that D(p) and k(a) values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2mm) under variably-saturated conditions for a given soil-air content (?), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D(p) and k(a) was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D(p)/D(f), the ratio of measured D(p) to D(p) in total porosity (f), (ii) for air permeability k(a)/k(a)(,pF4.1), the ratio of measured k(a) to k(a) at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content (?) to total porosity (f) (air saturation). Based on the normalized parameters, predictive power-law models for D(p)(?/f) and k(a)(?/f) models were developed based on a single parameter (water blockage factor M for D(p) and P for k(a)). The water blockage factors, M and P, were found to be linearly correlated to ?(b) values, and the effects of dry bulk density on D(p) and k(a) for both '+gravel' and '-gravel' fractions were well accounted for by the new models. PMID:21813272

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

2011-12-01

162

Prediction of Combustion Gas Deposit Compositions  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

163

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 8700 m(3) of wastewater per year, was conceptually designed in order to calculate the capital and operational costs of the facility (transportation, storage, treatment, final disposal). The proposed facility was found to be economically self-sufficient, as long as the transportation costs of the OMW were maintained at ?4.0 €/m(3). Despite that EU Landfill Directive prohibits wastewater disposal to landfills, controlled application, based on appropriately designed pre-treatment system and specific loading rates, may provide improved landfill stabilization and a sustainable (environmentally and economically) solution for effluents generated by numerous small- and medium-size olive mill enterprises dispersed in the Mediterranean region. PMID:23792820

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

2013-10-15

164

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

PubMed

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

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

2012-07-01

165

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

166

Gas Permeable Chemochromic Compositions for Hydrogen Sensing  

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

167

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 ...

168

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

169

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

PubMed Central

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

170

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

171

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

172

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...

173

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 ...

174

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

175

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

176

Methane emissions from MBT landfills  

SciTech Connect

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

Heyer, K.-U., E-mail: heyer@ifas-hamburg.de; Hupe, K.; Stegmann, R.

2013-09-15

177

Application of gas chromatography-mass spectrometry preceded by solvent extraction to determine volatile fatty acids in wastewater of municipal, animal farm and landfill origin.  

PubMed

This study describes extraction of selected volatile fatty acids (VFAs) (containing from 2 up to 8 carbon atoms) with methyl-tert-butyl ether (MTBE) from polluted aqueous samples followed by separation, identification and quantification by gas chromatography coupled with mass spectrometry (GC-MS). Extraction parameters such as time and number of extractions, volume ratio, effect of acidification and salt addition were optimized with respect to recovery, enrichment factor and repeatability. The VFAs studied were separated using an open tubular capillary column Stabilwax-DA (crossbond polyethylene glycol treated with nitroterephtalic acid). The limits of quantitation (LOQ) of the procedure developed were on the level of 0.1 to 0.5 mg L(-1). The analysis of real samples of municipal raw and treated wastewater, animal farms wastewater, and also landfill leachates showed that always dominant was acetic acid. The content of VFAs in animal farms wastewater was a few times higher than in municipal wastewater and in municipal solid waste landfill leachates. In surface and ground water close to municipal landfill only acetic acid was detected at higher concentrations in outflow than inflow water. This indicates that slight leakage from the landfill must have occurred. PMID:21330701

Banel, Anna; Zygmunt, Bogdan

2011-01-01

178

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

SciTech Connect

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

Di Maria, Francesco, E-mail: francesco.dimaria@unipg.it; Sordi, Alessio; Micale, Caterina

2013-11-15

179

Characterisation of organic pollutants in textile wastewaters and landfill leachate by using toxicity-based fractionation methods followed by liquid and gas chromatography coupled to mass spectrometric detection  

Microsoft Academic Search

In the present work, the characterisation of toxic organic compounds present in complex mixtures like textile effluents and landfill leachates is proposed. The protocol developed for the wastewater characterisation is based on solid phase extraction (SPE) combined with toxicity-fractionation followed by high temperature-gas chromatography-mass spectrometry (HT-GC-MS) and liquid chromatography-mass spectrometry (LC-MS). In this work Daphnia magna was used as the

Monserrat Castillo; Damià Barceló

2001-01-01

180

Numerical modelling of multiphase flow and transport processes in landfills.  

PubMed

Waste material in municipal landfills can be described as heterogeneous porous media, where flow and transport processes of gases and liquids are combined with local material degradation. This paper deals with the basic formulation of a multiphase flow and transport model applicable to the numerical analysis of coupled transport and reaction processes inside landfills. The transport model treats landfills within the framework of continuum mechanics, where flow and transport processes are described on a macroscopic level. The composition of organic and inorganic matter in the solid phase and its degradation are modelled on a microscopic scale. The degradation model captures the different reaction schemes of various microbial activities. Subsequently, transport and reaction processes have to be coupled, since emissions at the surface and from the drainage layer depend on the flow of leachate and gas, the transport of various substances and heat, and the biodegradation of organic matter. The theoretical considerations presented here are fundamental to the development of numerical models for the simulation of multiphase flow and transport processes inside landfills coupled with biochemical reactions and heat generation. The implicit modelling of leachate and gas flows including growth and decay of micro-organisms are innovative contributions to landfill modelling PMID:16941996

Kindlein, Jonatham; Dinkler, Dieter; Ahrens, Hermann

2006-08-01

181

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

182

Gas treating process and composition  

SciTech Connect

This patent describes a process for the removal of H/sub 2/S from a sour gaseous stream. The process consists of: (a) contacting the sour gaseous stream in a contacting zone with an aqueous reaction solution, at a temperature not greater than about 160{sup 0}C, the reaction solution comprising an effective amount of vanadium V-containing ions to oxidize H/sub 2/S to elemental sulfur and being substantially free of anthraquinone disulfonate, and producing a sweet gas stream and an aqueous solution having a pH of 8-11 and containing sulfur and vanadium IV-containing ions, the reaction solution further comprising an amount of phosphate ions sufficient to provide a molar ratio of phosphate ions to vanadium IV-containing ions produced in solution of at least 0.1; (b) removing sulfur from the aqueous solution, producing an aqueous solution having reduced sulfur content; (c) regenerating aqueous solution having reduced sulfur content in a regenerating zone and producing regenerated reactant in the solution; and (d) returning regenerated solution from step (c) to the contacting zone for use as aqueous reaction solution therein.

Byers, D.L.

1989-06-20

183

Design, construction, and monitoring of landfills. Second edition  

SciTech Connect

This book is now available in a new edition--updated to keep pace with today`s highly regulated environmental climate. In addition to probing the best ways to design and build landfills, as well as how their performance is monitored over time. The book shows how to comply with the new regulations. It also covers landfill issues, emerging liner and cover technology, and seismic stability analysis, and offers detailed design steps and easy-to-follow worked examples. The following topics are included: site selection; leachate and gas generation; waste characterization; natural attenuation landfills; containment landfills; liner material; design of landfill elements; landfill construction; performance monitoring; landfill operation and economic analysis.

Bagchi, A.

1994-12-31

184

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

SciTech Connect

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

Wimmer, Bernhard, E-mail: bernhard.wimmer@ait.ac.at [AIT Austrian Institute of Technology GmbH, Health and Environment Department, Environmental Resources and Technologies, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria); Hrad, Marlies; Huber-Humer, Marion [Institute of Waste Management, Department of Water-Atmosphere-Environment, University of Natural Resources and Life Sciences, Muthgasse 107, 1190 Vienna (Austria); Watzinger, Andrea; Wyhlidal, Stefan; Reichenauer, Thomas G. [AIT Austrian Institute of Technology GmbH, Health and Environment Department, Environmental Resources and Technologies, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria)

2013-10-15

185

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 São Paulo could produce 637?GWh?y(-1) with landfill gas, 2368?GWh?y(-1) with incineration of municipal solid waste and 1177?GWh?y(-1) with incineration of refuse-derived fuel. The latter two scenarios could replace 27% and 13.5% of the residential electrical energy consumption in the city. This shows that thermal treatment might be a viable option of waste-to-energy in Brazil. PMID:25323146

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

2014-10-01

186

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

187

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

PubMed

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

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

2013-11-01

188

Interfacial composite membranes for gas separation  

SciTech Connect

The program concerns the preparation of a new type of ultrathin gas separation composite membrane. An interfacial polymerized layer was formed on the surface of a composite support membrane consisting of a microporous support overcoated with a 1 to 2 micrometer thick rubber sealing layer. The separation properties are solely determined by the interfacial polymerized layer. Several different polymerization chemistries and different sealing layer materials were evaluated. The best gas separation membranes were obtained by reacting 1,6-hexanediamine with 1,3,5-benzenetricarbonyl trichloride on a silicone rubber-coated polysulfone support. The membrane is selective for hydrogen over carbon dioxide and short-chain hydrocarbons. This shows that the membrane separates gases on the basis of their molecular size rather than by their solubility in the membrane. The membrane's hydrogen/carbon dioxide selectivity of 16 is exceptionally high.

Wijmans, J.G.

1988-11-01

189

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

NASA Astrophysics Data System (ADS)

Municipal Solid Waste (MSW) landfills have unique features: Wastes worldwide emit biogenic methane to the atmosphere of magnitude comparable to the total atmospheric buildup between 1980 and 1990. Carbon sequestered in landfills is large in geologic terms Management of decomposition in landfilled waste is desirable: (a) Control of waste decomposition and methane promises over tenfold cheaper greenhouse gas abatement compared to most other greenhouse gas abatement strategies. This is due in part to carbon sequestration and landfill gas energy offset of fossil fuel consumption (b) Landfill gas energy potential worldwide, is up to 1% of world energy. Use of landfill gas conserves a resource otherwise wasted (c) Monetary benefits of landfill life extension from decomposition and rapid volume reduction can be quite attractive This is a benefit for the US, where landfills are increasingly difficult and expensive to site. (d) Landfills containing mixed waste can be significant sources of atmospheric and groundwater pollutants needing control. Control is possible from advancing landfill management approaches (e) The stabilization of waste lessens pollutant risk and needs for costly long-term landfill aftercare. Greater control of landfill decomposition has been advocated in the form of "controlled" or "bioreactor" landfills. (SWANA, 1999; Reinhart and Townsend, 1996). Field trials are encouraging by several environmental/monetary criteria. Control of moisture and temperature have given fivefold or more acceleration of methane generation (Augenstein et al, 1998, 2000). There has been rapid volume loss of the landfilled waste as well, with conversion of waste organics to gas. Many trials over years have shown potential for abatement of pollutants in landfill leachate. Demonstration work by the solid waste management community attests to the benefits potential. Increasing field demonstrations, have been accompanied by observation and/or solution of several issues. As noted the heat generation in landfills may become controlling, Heat can be dissipated, but at energy and monetary cost. Increased waste liquid content, required for biological activity has been a concern. Offsetting risk is the accelerated treatment of many dissolved contaminants in landfill liquid with time. It has proven possible to manage liquid flows within environmental and regulatory constraints. There have been concerns about containment by chemosynthetic lining of leachate liquids draining from landfills. Yet molecular bonds of lining under anaerobic conditions could be expected to last for centuries (and in fact up to millenia). There is of course no landfill experience over millenia but analogous compounds of geologic relevance have shown very desirable long term stability. Two other areas being investigated are waste slope stability and the precipitation of carbonate salts The climate significance and geophysical issues with landfills will be discussed, and some experimental findings leading to conclusions will be reviewed

Augenstein, D.; Yazdani, R.

2002-12-01

190

Bringing new life to old landfills  

SciTech Connect

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

Rabasca, L.

1996-01-01

191

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

192

Quantifying Uncontrolled Air Emissions from Two Florida Landfills  

EPA Science Inventory

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

193

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

194

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

SciTech Connect

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

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

2014-06-03

195

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

196

Evaluation of interface shear strength of composite liner system and stability analysis for a landfill lining system in Thailand  

Microsoft Academic Search

The paper presents the case history of laboratory evaluation of the interface shear strength properties of various interfaces encountered in a modern day landfill with emphasis on proper simulation of field conditions and subsequent use of these results in the stability analyses of liner system. Over 70 large direct shear tests were systematically conducted to evaluate the interface shear strength

D. T. Bergado; G. V. Ramana; H. I. Sia; Varun

2006-01-01

197

Tunable composite membranes for gas separations  

SciTech Connect

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

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

1999-05-01

198

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

199

Int. J. Environment and Pollution, V0/. IS, No.4, 2001 Economic evaluation of a landfill system with gas  

E-print Network

Int. J. Environment and Pollution, V0/. IS, No.4, 2001 Economic evaluation of a landfill system recovery for municipal solid waste management: a case study', Int. J. Environment and Pollution, Vol. 15,No results in increasing environmental pollution. The state of an economy, to a large extent, influences

Columbia University

200

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

PubMed

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

López, Ana; Lobo, Amaya

2014-08-01

201

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

202

ESTIMATE OF METHANE EMISSIONS FROM U.S. LANDFILLS  

EPA Science Inventory

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

203

Evaluation of processed municipal wastes in landfill cells  

SciTech Connect

The U.S. Environmental Protection Agency (EPA) engaged Systems Technology Corporation (SYSTECH) to compare the leachates and gases produced by municipal solid wastes (MSW) that were processed in various ways prior to landfilling. Beginning in January 1975, five tests cells (buried landfill simulators) were monitored until August 1980. These five test cells contained municipal refuse in the following conditions: (1) shredded and baled, (2) baled, (3) baled and saturated with water, (4) shredded, and (5) nonprocessed. Leachate and gas samples were collected to determine moisture balances, leachate pollutant concentrations, and gas compositions in order to evaluate the processing methods. The baled wastes were found to produce large quantities of dilute leachate, while the shredded waste produced smaller quantities of more concentrated leachate, compared to nonprocessed waste.

Kemper, J.M.; Kleinhenz, N.J.; Swartzbaugh, J.T.

1984-11-01

204

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

205

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

PubMed

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

Bergersen, Ove; Haarstad, Ketil

2008-08-01

206

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

Microsoft Academic Search

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

Mohamed A. Haque

2009-01-01

207

Cleaner Landfills  

NASA Technical Reports Server (NTRS)

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

2000-01-01

208

Comparative Landfills  

NSDL National Science Digital Library

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

Wishart, Ray

209

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...

210

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

NASA Astrophysics Data System (ADS)

Sanitary landfilling is the dominant method of solid waste disposal in the United States, accounting for about 217 million tons of waste annually (U.S. EPA, 1997) and has more than doubled since 1960. In spite of increasing rates of reuse and recycling, population and economic growth will continue to render landfilling as an important and necessary component of solid waste management. Yolo County Department of Planning and Public Works, Division of Integrated Waste Management is demonstrating a new landfill technology called Bioreactor Landfill to better manage solid waste. In a Bioreactor Landfill, controlled quantities of liquid (leachate, groundwater, gray-water, etc.) are added and recirculated to increase the moisture content of the waste and improve waste decomposition. As demonstrated in a small-scale demonstration project at the Yolo County Central Landfill in 1995, this process significantly increases the biodegradation rate of waste and thus decreases the waste stabilization and composting time (5 to 10 years) relative to what would occur within a conventional landfill (30 to 50 years or more). When waste decomposes anaerobically (in absence of oxygen), it produces landfill gas (biogas). Biogas is primarily a mixture of methane, a potent greenhouse gas, carbon dioxide, and small amounts of Volatile Organic Compounds (VOC's) which can be recovered for electricity or other uses. Other benefits of a bioreactor landfill composting operation include increased landfill waste settlement which increases in landfill capacity and life, improved leachate chemistry, possible reduction of landfill post-closure management time, opportunity to explore decomposed waste for landfill mining, and abatement of greenhouse gases through highly efficient methane capture over a much shorter period of time than is typical of waste management through conventional landfilling. This project also investigates the aerobic decomposition of waste of 13,000 tons of waste (2.5 acre) for elimination of methane production and acceleration of waste decomposition. In the first phase of this project a 12-acre module that contains a 9.5-acre anaerobic cell and a 2.5-acre aerobic cell has been constructed and filled with over 220,000 tons of municipal solid waste. Water and leachate addition began in April 2002 and to date less than 200,000 gallons of liquid has been added to the 3.5-acre anaerobic cell. The waste filling phase of the aerobic cell was completed in June of 2002 and a 12-inches soil cover and 12-inches of greenwaste compost cover was placed on top of the cell. A vacuum will be applied to the piping within the waste to draw air through the landfill. Instrumentations have been installed to monitor the following parameters: waste temperature, moisture, leachate volumes, leachate hydraulic head over the primary liner, leachate composition, gas volumes and composition. A supervisory Control and Data Acquisition (SCADA) system has been installed to monitor and control the operation of the bioreactor cells. Waste samples were taken from each cell for laboratory testing in early June 2002.

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

2002-12-01

211

Tunable Composite Membranes for Gas Separations.  

SciTech Connect

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

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

1997-07-01

212

Quantifying capital goods for waste landfilling.  

PubMed

Materials and energy used for construction of a hill-type landfill of 4 million m(3) were quantified in detail. The landfill is engineered with a liner and leachate collections system, as well as a gas collection and control system. Gravel and clay were the most common materials used, amounting to approximately 260 kg per tonne of waste landfilled. The environmental burdens from the extraction and manufacturing of the materials used in the landfill, as well as from the construction of the landfill, were modelled as potential environmental impacts. For example, the potential impact on global warming was 2.5 kg carbon dioxide (CO2) equivalents or 0.32 milli person equivalents per tonne of waste. The potential impacts from the use of materials and construction of the landfill are low-to-insignificant compared with data reported in the literature on impact potentials of landfills in operation. The construction of the landfill is only a significant contributor to the impact of resource depletion owing to the high use of gravel and steel. PMID:23535149

Brogaard, Line K; Stentsøe, Steen; Willumsen, Hans Christian; Christensen, Thomas H

2013-06-01

213

An absorption spectrum amplifier for determining gas composition  

NASA Technical Reports Server (NTRS)

Compositions of gas samples are frequently studied by laser absorption spectroscopy. Sensitivity is improved by two orders of magnitude when absorption cell is placed inside an organic-dye laser cavity.

Zalewski, E. F.; Peterson, N. C.; Kurylo, M. J.; Bass, A. M.; Brown, W.; Keller, R. A.

1972-01-01

214

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

USGS Publications Warehouse

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

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

2012-01-01

215

Degradability of Chlorinated Solvents in Landfill Environment  

NASA Astrophysics Data System (ADS)

The use of landfills as an in situ remediation system represents a cost-effective alternative for groundwater remediation in the source area. This research was conducted to investigate the intrinsic bioattenuation capacity of the landfill ecosystem for chlorinated aliphatic hydrocarbons (CAHs). This research, using excavated refuse samples, studied how the reductive dechlorination of CAHs is linked to the decomposition of solid waste in landfills. Most research effort in groundwater remediation has focused on the contaminant plumes beneath and downgradient from landfills, while the source area remediation has received increasing attention. Bioreactor landfill and leachate recirculation projects have been planned and implemented by the USEPA and some states. However, the use of bioreactor landfill has primarily been considered only to expedite refuse decomposition. This research provides an understanding of the biological fate of CAHs in landfills, an understanding that can lead to the bioreactor landfill system designed to promote the degradation of pollutants right at the source. The research was conducted in two complementary systems: simulated landfill bioreactors and batch degradation experiment in serum bottles. Refuse samples were excavated from a municipal solid waste landfill located in Wayland, Massachusetts, USA. Bioreactors were designed and operated to facilitate refuse decomposition under landfilling conditions. For each reactor, leachate was collected and recirculated back to the reactor and gas was collected into a gas bag and the methane production rate was monitored. Target CAHs, tetrachloroethene (PCE) and trichloroethene (TCE), were added to selected reactors and maintained at about 20 uM each in leachate. The design is to study the effect of long-term exposure of refuse microorganisms to CAHs on the degradation potential of these chemicals in landfills. Changes of biochemical conditions in bioreactors, including leachate pH, leachate COD, and methane production, were monitored throughout the refuse decomposition process. At two different stages of refuse decomposition, active refuse decomposition representing young landfills and maturation phase representing aged landfills, anaerobic microbial cultures were derived from selected bioreactors and tested in serum bottles for their abilities to biodegrade target CAHs. Complementary to the bioreactor experiment, the serum bottle experiment was designed to investigate specific conditions that potentially control or limit the reductive dechlorination of CAHs in landfills. The conditions tested include 1) inhibited refuse methanogenesis, 2) enhanced methanogenic refuse decomposition, 3) presence of other organic carbons commonly found in landfills such as cellulose, lactate, ethanol, and acetate and 4) presence of yeast extract and humic acids which are commonly found in aged landfills. This research investigated the degradability, the degradation rate, and the extent of dechlorination of CAHs in a landfill ecosystem as the refuse decomposition progresses. The results can lead to a broader application of the intrinsic bioattenuation capacity of landfills. An in situ remedial strategy directly tackling the contaminant source can minimize the risk of future impact and achieve a significant saving in remediation cost. The information of contaminant fate in landfills can also help regulatory agencies formulate risk-based guidelines for post-closure monitoring programs and potential re-development projects.

Wang, J. Y.; Litman, M.

2002-12-01

216

40 CFR Table Hh-4 to Subpart Hh of... - Landfill Methane Oxidation Fractions  

Code of Federal Regulations, 2014 CFR

...SArea = The surface area of the landfill containing waste at the beginning...Collection efficiency estimated at landfill, taking into account system...collection system. N = Number of landfill gas measurement locations...destruction device or gas sent off-site). If a single...

2014-07-01

217

Characterization of ceramic composite materials for gas turbine applications  

Microsoft Academic Search

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

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

1993-01-01

218

Gas Composition Sensing Using Carbon Nanotube Arrays  

NASA Technical Reports Server (NTRS)

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

Li, Jing; Meyyappan, Meyya

2012-01-01

219

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

220

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

PubMed

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. PMID:16714103

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

2007-01-01

221

Bisphenol A in hazardous waste landfill leachates  

Microsoft Academic Search

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

Takashi Yamamoto; Akio Yasuhara; Hiroaki Shiraishi; Osami Nakasugi

2001-01-01

222

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.

2012-12-20

223

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

224

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

225

Gas composition sensing using carbon nanotube arrays  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

226

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

PubMed

Landfills are some of the major anthropogenic sources of methane emissions worldwide. The installation and operation of gas extraction systems for many landfills in Europe and the US, often including technical installations for energy recovery, significantly reduced these emissions during the last decades. Residual landfill gas, however, is still continuously produced after the energy recovery became economically unattractive, thus resulting in ongoing methane emissions for many years. By landfill in situ aeration these methane emissions can be widely avoided both, during the aeration process as well as in the subsequent aftercare period. Based on model calculations and online monitoring data the amount of avoided CO(2-eq). can be determined. For an in situ aerated landfill in northern Germany, acting as a case study, 83-95% (depending on the kind and quality of top cover) of the greenhouse gas emission potential could be reduced under strictly controlled conditions. Recently the United Nations Framework Convention on Climate Change (UNFCCC) has approved a new methodology on the "Avoidance of landfill gas emissions by in situ aeration of landfills" (UNFCCC, 2009). Based on this methodology landfill aeration projects might be considered for generation of Certified Emission Reductions (CERs) in the course of CDM projects. This paper contributes towards an evaluation of the potential of landfill aeration for methane emissions reduction. PMID:20022235

Ritzkowski, M; Stegmann, R

2010-04-01

227

COMPOSITION OF LOW-REDSHIFT HALO GAS  

SciTech Connect

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

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

2013-06-20

228

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

SciTech Connect

Highlights: > We conduct 1D advection-dispersion modeling to estimate transport parameters. > We examine fourteen phenolic compounds and three inorganic contaminants. > 2-MP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,3,4,6-TeCP have the highest coefficients. > Dispersion coefficients of Cu are determined to be higher than Zn and Fe. > Transport of phenolics can be prevented by zeolite and bentonite in landfill liners. - Abstract: One-dimensional (1D) advection-dispersion transport modeling was conducted as a conceptual approach for the estimation of the transport parameters of fourteen different phenolic compounds (phenol, 2-CP, 2-MP, 3-MP, 4-MP, 2-NP, 4-NP, 2,4-DNP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,4,6-TCP, 2,3,4,6-TeCP, PCP) and three different inorganic contaminants (Cu, Zn, Fe) migrating downward through the several liner systems. Four identical pilot-scale landfill reactors (0.25 m{sup 3}) with different composite liners (R1: 0.10 + 0.10 m of compacted clay liner (CCL), L{sub e} = 0.20 m, k{sub e} = 1 x 10{sup -8} m/s, R2: 0.002-m-thick damaged high-density polyethylene (HDPE) geomembrane overlying 0.10 + 0.10 m of CCL, L{sub e} = 0.20 m, k{sub e} = 1 x 10{sup -8} m/s, R3: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick bentonite layer encapsulated between 0.10 + 0.10 m CCL, L{sub e} = 0.22 m, k{sub e} = 1 x 10{sup -8} m/s, R4: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick zeolite layer encapsulated between 0.10 + 0.10 m CCL, L{sub e} = 0.22 m, k{sub e} = 4.24 x 10{sup -7} m/s) were simultaneously run for a period of about 540 days to investigate the nature of diffusive and advective transport of the selected organic and inorganic contaminants. The results of 1D transport model showed that the highest molecular diffusion coefficients, ranging from 4.77 x 10{sup -10} to 10.67 x 10{sup -10} m{sup 2}/s, were estimated for phenol (R4), 2-MP (R1), 2,4-DNP (R2), 2,4-DCP (R1), 2,6-DCP (R2), 2,4,5-TCP (R2) and 2,3,4,6-TeCP (R1). For all reactors, dispersion coefficients of Cu, ranging from 3.47 x 10{sup -6} m{sup 2}/s to 5.37 x 10{sup -2} m{sup 2}/s, was determined to be higher than others obtained for Zn and Fe. Average molecular diffusion coefficients of phenolic compounds were estimated to be about 5.64 x 10{sup -10} m{sup 2}/s, 5.37 x 10{sup -10} m{sup 2}/s, 2.69 x 10{sup -10} m{sup 2}/s and 3.29 x 10{sup -10} m{sup 2}/s for R1, R2, R3 and R4 systems, respectively. The findings of this study clearly indicated that about 35-50% of transport of phenolic compounds to the groundwater is believed to be prevented with the use of zeolite and bentonite materials in landfill liner systems.

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

2011-11-15

229

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

230

DEVELOPMENT OF AN EMPIRICAL MODEL OF METHANE EMISSIONS FROM LANDFILLS  

EPA Science Inventory

The report gives results of a field study of 21 U.S. landfills with gas recovery systems, to gather information that can be used to develop an empirical model of methane (CH4) emissions. Site-specific information includes average CH4 recovery rate, landfill size, tons of refuse (...

231

DEVELOPMENT OF AN EMPIRICAL MODEL OF METHANE EMISSIONS FROM LANDFILLS  

EPA Science Inventory

The report gives results of a field study of 21 U.S. landfills with gas recovery systems, to gather information that can be used to develop an empirical model of methane (CH4) emissions. ite-specific information includes average CH4 recovery rate, landfill size, tons of refuse (r...

232

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...

233

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

EPA Science Inventory

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

234

LANDFILLS EFFLUENT LIMITATIONS GUIDELINES DATABASE  

EPA Science Inventory

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

235

40 CFR 60.33c - Emission guidelines for municipal solid waste landfill emissions.  

Code of Federal Regulations, 2010 CFR

...capacity report; and (3) The landfill has a nonmethane organic compound...of this part at each MSW landfill meeting the conditions in...site-specific design plans for the gas collection and control system...the control of collected MSW landfill emissions through the use...

2010-07-01

236

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

Code of Federal Regulations, 2012 CFR

...Because of the many site-specific factors involved with landfill gas system design...entire area of the landfill that warrants control...group of cells in the landfill in which the initial...to minimize off-site migration of...

2012-07-01

237

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

Code of Federal Regulations, 2011 CFR

...Because of the many site-specific factors involved with landfill gas system design...entire area of the landfill that warrants control...group of cells in the landfill in which the initial...to minimize off-site migration of...

2011-07-01

238

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

Code of Federal Regulations, 2013 CFR

...Because of the many site-specific factors involved with landfill gas system design...entire area of the landfill that warrants control...group of cells in the landfill in which the initial...to minimize off-site migration of...

2013-07-01

239

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

Code of Federal Regulations, 2014 CFR

...Because of the many site-specific factors involved with landfill gas system design...entire area of the landfill that warrants control...group of cells in the landfill in which the initial...to minimize off-site migration of...

2014-07-01

240

Tunable Composite Membranes for Gas Separations.  

SciTech Connect

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

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

1997-10-01

241

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

242

Landfill disposal systems  

PubMed Central

The current status of landfill disposal of hazardous wastes in the United States is indicated by presenting descriptions of six operating landfills. These landfills illustrate the variety of techniques that exist in landfill disposal of hazardous wastes. Although some landfills more effectively isolate hazardous waste than others, all landfills must deal with the following problems. Leachate from hazardous waste landfills is generally highly polluted. Most landfills attempt to contain leachate at the site and prevent its discharge to surface or groundwaters. To retain leachate within a disposal area, subsurface barriers of materials such as concrete, asphalt, butyl rubber, vinyl, and clay are used. It is difficult to assure that these materials can seal a landfill indefinitely. When a subsurface barrier fails, the leachate enters the groundwater in a concentrated, narrow band which may bypass monitoring wells. Once a subsurface barrier has failed, repairs are time-consuming and costly, since the waste above the repair site may have to be removed. The central problem in landfill disposal is leachate control. Recent emphasis has been on developing subsurface barriers to contain the wastes and any leachate. Future emphasis should also be on techniques for removing water from hazardous wastes before they are placed in landfills, and on methods for preventing contact of the wastes with water during and after disposal operations. When leachate is eliminated, the problems of monitoring, and subsurface barrier failure and repair can be addressed, and a waste can be effectively isolated. A surface seal landfill design is recommended for maintaining the dry state of solid hazardous wastes and for controlling leachate. Any impervious liner is utilized over the top of the landfill to prevent surface water from seeping into the waste. The surface barrier is also the site where monitoring and maintenance activities are focused. Barrier failure can be detected by visual inspections and any repairs can be made without disturbing the waste. The surface seal landfill does not employ a subsurface barrier. The surface seal landfill successfully addresses each of the four environmental problems listed above, provided that this landfill design is utilized for dry wastes only and is located at a site which provides protection from groundwater and temporary perched water tables. ImagesFIGURE 3.FIGURE 4.FIGURE 7.FIGURE 7. PMID:738247

Slimak, Karen M.

1978-01-01

243

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

244

Using LNG to meet the challenge of gas composition  

SciTech Connect

Currently NGV fuel providers are taking actions in response to customer concerns regarding moisture and oil in compressed natural gas (CNG) fuel. Dryers are being installed and oil coalescing or non-lubricated compression equipment is being evaluated in order to minimize problems. Some utilities actively pursuing the NGV market utilize propane-air peak shaving plants to meet cold weather distribution systems demands. The effects of adding these heavier hydrocarbons have not yet appeared to result in major NGV engine problems. However, commercialization of new engine technologies will result in engines that are more fuel sensitive. As the market matures and engine tolerances narrow, increasingly stringent fuel quality standards will be developed and enforced. The Natural Gas Vehicle Technology Partnership has a proposed plan for its Fuel Composition Project which tentatively targets establishing an enforcement mechanisms for meeting gas composition standards in all fifty states as early as December 1996. Propane-air peak shaving utilities need to evaluate how they will address NGV gas quality requirements or risk serious engine problems and customer dissatisfaction. LNG may be a viable solution to meeting gas composition requirements.

Pehrson, N.C. [Minnegasco, Minneapolis, MN (United States)

1995-12-31

245

Gas treatment of Cr(VI)-contaminated sediment samples from the North 60`s pits of the chemical waste landfill  

Microsoft Academic Search

Twenty sediment samples were collected at depths ranging from 5 to 100 ft (1.5 to 30 m) beneath a metal-contaminated plating-waste site and extensively characterized for Cr(VI) content and environmental availability. Three samples were selected for treatment with diluted gas mixtures with the objective of converting Cr(VI) to Cr(III), which is relatively nontoxic and immobile. These tests were designed to

E. C. Thornton; J. E. Amonette

1997-01-01

246

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

247

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

PubMed

Whole-site methane emissions from 15 Danish landfills were assessed using a mobile tracer dispersion method with either Fourier transform infrared spectroscopy (FTIR), using nitrous oxide as a tracer gas, or cavity ring-down spectrometry (CRDS), using acetylene as a tracer gas. The landfills were chosen to represent the different stages of the lifetime of a landfill, including open, active, and closed covered landfills, as well as those with and without gas extraction for utilisation or flaring. Measurements also included landfills with biocover for oxidizing any fugitive methane. Methane emission rates ranged from 2.6 to 60.8 kg h(-1), corresponding to 0.7-13.2 g m(-2)d(-1), with the largest emission rates per area coming from landfills with malfunctioning gas extraction systems installed, and the smallest emission rates from landfills closed decades ago and landfills with an engineered biocover installed. Landfills with gas collection and recovery systems had a recovery efficiency of 41-81%. Landfills where shredder waste was deposited showed significant methane emissions, with the largest emission from newly deposited shredder waste. The average methane emission from the landfills was 154 tons y(-1). This average was obtained from a few measurement campaigns conducted at each of the 15 landfills and extrapolating to annual emissions requires more measurements. Assuming that these landfills are representative of the average Danish landfill, the total emission from Danish landfills were calculated at 20,600 tons y(-1), which is significantly lower than the 33,300 tons y(-1) estimated for the national greenhouse gas inventory for 2011. PMID:25442105

Mønster, Jacob; Samuelsson, Jerker; Kjeldsen, Peter; Scheutz, Charlotte

2015-01-01

248

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

SciTech Connect

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. [School of Energy Science and Engineering, Central South University, Changsha 410083 (China); Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States); Liao, S. M. [School of Energy Science and Engineering, Central South University, Changsha 410083 (China); Tsai, H. L. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States)

2010-02-15

249

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

250

TUNABLE COMPOSITE MEMBRANES FOR GAS SEPARATIONS  

SciTech Connect

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

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

1998-10-01

251

The Gas Leakage Analysis in C/C Composites  

NASA Astrophysics Data System (ADS)

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

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

252

Characterization of ceramic composite materials for gas turbine applications  

SciTech Connect

Ceramic composite materials have the capability to sustain high stress in the presence of high temperatures and aggressive atmospheres. Such materials are being considered for application as cumbustors, burner cubes, heat exchangers, headers. hot-gas filters, and even rotors of stationary gas turbine engines. In the present program, Nicalon preforms of tubular geometry were fabricated with different fiber architectures (filament winding, 3D braiding, or cloth winding) to tailor the mechanical properties for specific applications. However, these applications require that candidate materials be carefully characterized. Mechanical characterization must establish the properties and performance that are essential for structural design of the turbine components. For this purpose, a full complement of properties is needed, i.e., the stiffness and strengths of the composite material at a range of temperatures, and the fatigue and creep behavior of the materials under the stress states anticipated by the user. This mechanical characterization requires specialized equipment and methodologies, which are now under development by the authors. This paper will present a description of the methodologies required for ceramic composite characterization, and will describe initial results for ceramic composite tubes, a representative geometry for gas turbine components. Future needs and opportunities will also be discussed.

Reifsnider, K.; Stinchcomb, W.; Liao, K.; Oleksuk, L. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States); Stinton, D. [Oak Ridge National Lab., TN (United States)

1993-05-01

253

Characterization of ceramic composite materials for gas turbine applications  

SciTech Connect

Ceramic composite materials have the capability to sustain high stress in the presence of high temperatures and aggressive atmospheres. Such materials are being considered for application as cumbustors, burner cubes, heat exchangers, headers. hot-gas filters, and even rotors of stationary gas turbine engines. In the present program, Nicalon preforms of tubular geometry were fabricated with different fiber architectures (filament winding, 3D braiding, or cloth winding) to tailor the mechanical properties for specific applications. However, these applications require that candidate materials be carefully characterized. Mechanical characterization must establish the properties and performance that are essential for structural design of the turbine components. For this purpose, a full complement of properties is needed, i.e., the stiffness and strengths of the composite material at a range of temperatures, and the fatigue and creep behavior of the materials under the stress states anticipated by the user. This mechanical characterization requires specialized equipment and methodologies, which are now under development by the authors. This paper will present a description of the methodologies required for ceramic composite characterization, and will describe initial results for ceramic composite tubes, a representative geometry for gas turbine components. Future needs and opportunities will also be discussed.

Reifsnider, K.; Stinchcomb, W.; Liao, K.; Oleksuk, L. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)); Stinton, D. (Oak Ridge National Lab., TN (United States))

1993-01-01

254

LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL  

SciTech Connect

Controlled landfilling is an approach to manage solid waste landfills, so as to rapidly complete methane generation, while maximizing gas capture and minimizing the usual emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated to more rapid and earlier completion to full potential by improving conditions (principally moisture, but also temperature) to optimize biological processes occurring within the landfill. Gas is contained through use of surface membrane cover. Gas is captured via porous layers, under the cover, operated at slight vacuum. A field demonstration project has been ongoing under NETL sponsorship for the past several years near Davis, CA. Results have been extremely encouraging. Two major benefits of the technology are reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times, more predictably, than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role both in reduction of US greenhouse gas emissions and in US renewable energy. The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 metric tons [tonnes]), sufficient to replicate many heat and compaction characteristics of larger ''full-scale'' landfills. An enhanced demonstration cell has received moisture supplementation to field capacity. This is the maximum moisture waste can hold while still limiting liquid drainage rate to minimal and safely manageable levels. The enhanced landfill module was compared to a parallel control landfill module receiving no moisture additions. Gas recovery has continued for a period of over 4 years. It is quite encouraging that the enhanced cell methane recovery has been close to 10-fold that experienced with conventional landfills. This is the highest methane recovery rate per unit waste, and thus progress toward stabilization, documented anywhere for such a large waste mass. This high recovery rate is attributed to moisture, and elevated temperature attained inexpensively during startup. Economic analyses performed under Phase I of this NETL contract indicate ''greenhouse cost effectiveness'' to be excellent. Other benefits include substantial waste volume loss (over 30%) which translates to extended landfill life. Other environmental benefits include rapidly improved quality and stabilization (lowered pollutant levels) in liquid leachate which drains from the waste.

Don Augenstein; Ramin Yazdani; Rick Moore; Michelle Byars; Jeff Kieffer; Professor Morton Barlaz; Rinav Mehta

2000-02-26

255

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.

256

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

257

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

258

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

PubMed

The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm(-3), reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100g CH(4)m(-2)d(-1), covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH(4)m(-2)d(-1) and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity and diffusive ingress of atmospheric air. For one material with elevated levels of fine particles and high organic matter content, methane production impeded the quantification of methane oxidation potentials. Regarding the design of landfill cover layers it was concluded that the magnitude of the expected methane load, the texture and expected compaction of the cover material are key variables that need to be known. Based on these, a column study can serve as an appropriate testing system to determine the methane oxidation capacity of a soil intended as landfill cover material. PMID:21067907

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

2011-05-01

259

Hydrological and geochemical factors affecting leachate composition in municipal solid waste incinerator bottom ash. Part II. The geochemistry of leachate from Landfill Lostorf, Switzerland  

NASA Astrophysics Data System (ADS)

The leachate composition of the Landfill Lostorf, Buchs, Switzerland has been examined as a function rain events and dry periods between November 1994 and November 1996. Discharge and electrical conductivity of the central drainage discharge were monitored continuously, whilst samples for chemical analysis were taken at discrete intervals. The average total concentrations of Na, Cl, K, Mg, Ca and SO 4 are 44.5, 47.1, 11.8, 0.63, 8.2 and 12.4 mM, respectively. During rain events, the leachate is diluted by the preferential flow of rainwater into the drainage discharge. Drainage discharge pH values range between 8.68 and 11.28, the latter under dry conditions. Thermodynamic calculations indicate that CaSO 4, ettringite (3CaOAl 2O 3CaSO 4·32H 2O) and Al(OH) 3 may control the concentrations of the components Ca, SO 4 and Al. Dissolved Si may be in thermodynamic equilibrium with either Ca silicate hydrate or imogolite. Cadmium, Mo, V, Mn and Zn are also diluted during rain events and concentration changes agree with those of conductivity (representing the major constituents). Average concentrations are 0.012, 5.4, 2.3, 0.085, and 0.087 ?M, respectively. Components such as Al, Cu, Sb and Cr increase in concentration with increased discharge. Average concentrations are 1.6, 0.27 and 0.21 ?M, respectively. For Cu, the explanation lies in its affinity for total organic carbon (TOC). Thermodynamic calculations indicate that whilst dissolution/precipitation reactions with metal hydroxides and carbonates can explain the observed concentrations of Cd, sorption and complexation reactions probably influence the concentrations of Cu, Pb (average measurable concentration 0.013 ?M), Zn and Mn. For the oxyanion species such as MoO 4 and WO 4 (average concentration 0.61 ?M), it is probable that Ca metallate formation plays a dominant role in determining concentration ranges. Geochemical processes appear to determine concentration ranges and the hydrological factors, the fluctuations in concentration.

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

1999-12-01

260

Attenuation of landfill leachate pollutants in aquifers  

Microsoft Academic Search

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

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

1994-01-01

261

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

262

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

SciTech Connect

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

Gregory Corman; Krishan Luthra

2005-09-30

263

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

PubMed

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

Meidiana, Christia; Gamse, Thomas

2011-01-01

264

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

SciTech Connect

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

Kubesh, J.T.

1992-05-01

265

Shielding gas composition and electrode geometry influence on arc properties  

SciTech Connect

The effects of welding electrode geometry and of shielding gas composition using pure argon, argon-helium mixtures, and an argon-hydrogen mixture on welding arc properties, particularly acr temperature distribution was studied. Plasma diagnostic techniques were used to measure the arc properties presented. A computer-controlled emission spectroscopy system comprised of an Optical Multichannel Analyzer (OMA) interfaced to 0.3-m monochromator was used to make temperature and composition measurements. Electrode tip geometry was found to have a somewhat restricted influence on arc temperature distribution. The addition of significant amounts of helium to argon shielding gas causes a gas tungsten arc to be a broader, more isothermal, heat source than an arc shielded with pure argon. Blunt electrode tip geometries, compared to sharp ones, tend to cause flatter temperature distributions in pure argon but have temperature distributions similar to sharp electrode tips in moderate to high helium environments. Thermophysical properties of the shielding gas constituents appear to have greater influence on fusion zone profile than does arc temperature. However, refined heat transfer models of the future will require arc temperature distributions as a function of essential welding variables since these models will use properties which are strongly temperature dependent.

Key, J.F.; McIlwain, M.E.

1981-01-01

266

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

267

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

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

2012-12-01

268

Landfill leachate treatment: Review and opportunity.  

PubMed

In most countries, sanitary landfilling is nowadays the most common way to eliminate municipal solid wastes (MSW). In spite of many advantages, generation of heavily polluted leachates, presenting significant variations in both volumetric flow and chemical composition, constitutes a major drawback. Year after year, the recognition of landfill leachate impact on environment has forced authorities to fix more and more stringent requirements for pollution control. This paper is a review of landfill leachate treatments. After the state of art, a discussion put in light an opportunity and some results of the treatment process performances are given. Advantages and drawbacks of the various treatments are discussed under the items: (a) leachate transfer, (b) biodegradation, (c) chemical and physical methods and (d) membrane processes. Several tables permit to review and summarize each treatment efficiency depending on operating conditions. Finally, considering the hardening of the standards of rejection, conventional landfill leachate treatment plants appear under-dimensioned or do not allow to reach the specifications required by the legislator. So that, new technologies or conventional ones improvements have been developed and tried to be financially attractive. Today, the use of membrane technologies, more especially reverse osmosis (RO), either as a main step in a landfill leachate treatment chain or as single post-treatment step has shown to be an indispensable means of achieving purification. PMID:17997033

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

2008-02-11

269

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.

Association of Zoos and Aquariums

2009-01-01

270

Acetate and propionate in landfill leachates: Implications for the recognition of microbiological influences on the composition of waters in sedimentary systems  

NASA Astrophysics Data System (ADS)

Routine monitoring of landfill leachates provides information concerning aqueous systems in which anaerobic microbiological processes influence water chemistry. Propionate and acetate are substrate and product, respectively, of metabolism by bacteria that have an obligate syntrophic relationship with sulfate-reducing bacteria. The stoichiometry of the bacteriological metabolic reactions indicates a 1:1 molar proportionality for acetate and propionate. This is observed for landfill leachates, consistent with the known biological control on their organic acid anion contents. Similar data for oil-field waters show the same 1:1 molar proportionality for reservoirs where bacterial sulfate reduction is known to take place, at temperatures up to about 95 °C, in contrast to the 3:2 proportionality (acetic acid:propionic acid) observed in higher temperature systems. These observations suggest that 1:1 molar proportionality for acetate and propionate may be characteristic of natural systems where anaerobic bacterial activity occurs, including bacterial sulfate reduction.

Manning, D. A. C.

1997-03-01

271

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

NASA Astrophysics Data System (ADS)

Production of biogas as a result of the decomposition of organic matter included on solid waste landfills is still an issue to be understood. Reports on this matter are rarely included on the engineering construction projects of solid waste landfills despite it can be an issue of critical importance while operating the landfill and after its closure. This paper presents an application of BGP (Bio-Gas-Production) model to a synthetic landfill. The evolution in time of the concentrations of the different chemical compounds of biogas is studied. Results obtained show the impact on the air quality of different management alternatives which are usually performed in real landfills.

Rodrigo-Ilarri, Javier; Segura-Sobrino, Francisco

2013-04-01

272

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

PubMed

Methane generated at landfills contributes to global warming and can be mitigated by biocover systems relying on microbial methane oxidation. As part of a closure plan for an old unlined landfill without any gas management measures, an innovative biocover system was established. The system was designed based on a conceptual model of the gas emission patterns established through an initial baseline study. The study included construction of gas collection trenches along the slopes of the landfill where the majority of the methane emissions occurred. Local compost materials were tested as to their usefulness as bioactive methane oxidizing material and a suitable compost mixture was selected. Whole site methane emission quantifications based on combined tracer release and downwind measurements in combination with several local experimental activities (gas composition within biocover layers, flux chamber based emission measurements and logging of compost temperatures) proved that the biocover system had an average mitigation efficiency of approximately 80%. The study showed that the system also had a high efficiency during winter periods with temperatures below freezing. An economic analysis indicated that the mitigation costs of the biocover system were competitive to other existing greenhouse gas mitigation options. PMID:24755356

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

2014-07-01

273

Gas compositional and pressure effects on thermographic phosphor thermometry  

NASA Astrophysics Data System (ADS)

In the present study, the influence of gas compositional and pressure conditions on thermographic phosphor thermometry was investigated. A heatable pressurized and optical accessible calibration chamber was built to measure the phosphorescence decay time at different temperatures as well as at different partial and absolute pressures. At room temperature, the absolute pressure could be increased to 30 bar. To vary the gas composition, nitrogen, oxygen, carbon dioxide, methane, helium as well as water vapour were used. Three different phosphors were investigated: Mg4FGeO6:Mn, La2O2S:Eu and Y2O3:Eu. Phosphorescence was excited by the third and the fourth harmonics of a pulsed Nd:YAG-laser (355 nm and 266 nm, respectively) and recorded temporally resolved by a photomultiplier. Mg4FGeO6:Mn as well as La2O2S:Eu were not influenced significantly by varying partial and absolute pressures. In contrast, Y2O3:Eu showed a strong sensitivity on the oxygen concentration of the surrounding gas phase as well as irreversible changes in the phosphorescence decay time after increasing the absolute pressure.

Brübach, J.; Dreizler, A.; Janicka, J.

2007-03-01

274

78 FR 10261 - Pipeline Safety: Information Collection Activities, Revision to Gas Distribution Annual Report  

Federal Register 2010, 2011, 2012, 2013, 2014

...forms. These commodity groups include ``Natural Gas,'' ``Synthetic Gas,'' ``Hydrogen Gas,'' ``Propane Gas,'' ``Landfill Gas,'' and ``Other Gas.'' Operators will select a commodity group based on the predominant...

2013-02-13

275

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

276

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

277

Ceramic Composite Development for Gas Turbine Engine Hot Section Components  

NASA Technical Reports Server (NTRS)

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

DiCarlo, James A.; VANrOODE, mARK

2006-01-01

278

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

Microsoft Academic Search

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

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

2004-01-01

279

Clean Air Act Title III accidental emission release risk management program, and how it applies to landfills  

SciTech Connect

On June 20, 1996, EPA promulgated regulations pursuant to Title III of the Clean Air Act (CAA) Amendments of 1990 (Section 112(r)(7) of the CAA). The rule, contained in 40 CFR Part 68, is called Accidental Release Prevention Requirements: Risk Management Programs, and is intended to improve accident prevention and emergency response practices at facilities that store and/or use hazardous substances. Methane is a designated highly hazardous chemical (HHC) under the rule. The rule applies to facilities that have 10,000 pounds of methane or more in any process, roughly equivalent to about 244,000 cubic feet of methane. The US EPA has interpreted this threshold quantity as applying to landfill gas within landfills. This paper presents an overview of the Accidental Release Prevention regulations, and how landfills are affected by the requirements. This paper describes methodologies for calculating the threshold quantity of landfill gas in a landfill. Methane is in landfill gas as a mixture. Because landfill gas can burn readily, down to concentrations of about five percent methane, the entire landfill gas mixture must be treated as the regulated substance, and counts toward the 10,000-pound threshold. It is reasonable to assume that the entire landfill gas collection system, active or passive, is filled with landfill gas, and that a calculation of the volume of the system would be a calculation of the landfill gas present in the process on the site. However, the US EPA has indicated that there are some instances in which pore space gas should be included in this calculation. This paper presents methods available to calculate the amount of pore space gas in a landfill, and how to determine how much of that gas might be available for an explosion. The paper goes through how to conduct the release assessment to determine the worst-case hazard zone around the landfill.

Hibbard, C.S.

1999-07-01

280

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

Microsoft Academic Search

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

Daniel J. K. Ross; R. Marc Bustin

2009-01-01

281

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)...

282

Quantifying Methane Abatement Efficiency at Three Municipal Solid Waste Landfills; Final Report  

EPA Science Inventory

Measurements were conducted at three municipal solid waste landfills to compare fugitive methane emissions from the landfill cells to the quantity of collected gas (i.e., gas collection efficiency). The measurements were conducted over a multi-week sampling campaign using EPA Oth...

283

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

284

Compositions and Greenhouse Gas Emission Factors of Flared and Vented Gas in the Western Canadian Sedimentary Basin  

Microsoft Academic Search

A significant obstacle in evaluating mitigation strategies for flaring and venting in the upstream oil and gas industry is the lack of publicly available data on the chemical composition of the gas. This information is required to determine the economic value of the gas, infrastructure and processing requirements, and potential emissions or emissions credits, all of which have significant impact

Matthew R. Johnson; Adam R. Coderre

2012-01-01

285

Biotic landfill cover treatments for mitigating methane emissions.  

PubMed

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

Hilgeri, Helene; Humer, Marion

2003-05-01

286

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

287

Methane Rates in the Landfill Leachate Plume Of Wuhan Erfei Shan Landfill, China  

NASA Astrophysics Data System (ADS)

: This paper presents the result of methane analysis in leachate, air and groundwater samples collected at Wuhan Erfei Shan Landfill. Eleven multilevel sampling wells ranging from 1.5 to 10 m were chosen for groundwater sampling, three locations were chosen for leachate sampling and four locations were chosen for air sampling. The method of gas chromatography fitted with FID detector (GC-FID) was used for the determination of methane in samples. In all samples, leachates samples presented high dissolved methane concentration (average is 49.168 mg/L), while dissolved methane was only detected in 3 groundwater wells with low depth and close to the landfill. The distance and depth distribution showed a variation of redox species with methane. High methane concentrations were identified closest to the landfill and at low depths (methanogenesis zone). Sulfate and nitrate zone overlapped but elevated concentrations of sulfate zone were observed between 400 and 600 m far from the landfill and between 4 and 8 m depths. In the zone of elevated sulfate concentrations, methane was depleted. The average ambient methane levels at Wuhan Erfei Shan landfill were found to be 50.87 ppm for SA1, 119.109 ppm for SA2, 14.199ppm for SA3 and 90 ppm for SA4. Although average methane concentrations in air samples were not high compared to leachate samples, the greenhouse effects of such concentrations in air is enormous.

Zhang, C.; Wang, Y.

2010-12-01

288

Quantifying biomass composition by gas chromatography/mass spectrometry.  

PubMed

We developed a set of methods for the quantification of four major components of microbial biomass using gas chromatography/mass spectrometry (GC/MS). Specifically, methods are described to quantify amino acids, RNA, fatty acids, and glycogen, which comprise an estimated 88% of the dry weight of Escherichia coli. Quantification is performed by isotope ratio analysis with fully (13)C-labeled biomass as internal standard, which is generated by growing E. coli on [U-(13)C]glucose. This convenient, reliable, and accurate single-platform (GC/MS) workflow for measuring biomass composition offers significant advantages over existing methods. We demonstrate the consistency, accuracy, precision, and utility of this procedure by applying it to three metabolically unique E. coli strains. The presented methods will have widespread applicability in systems microbiology and bioengineering. PMID:25208224

Long, Christopher P; Antoniewicz, Maciek R

2014-10-01

289

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

290

Post-closure care of engineered municipal solid waste landfills.  

PubMed

Post-closure care is divided into perpetual care (PPC) and long-term care (LTC). Guidelines for post-closure care and associated costs are important for engineered municipal solid waste (MSW) landfills. In many states in the USA, landfill owners are required to set aside funds for 30-40 years of LTC. Currently there are no guidelines for PPC, which is also required. We undertook a pilot study, using two landfills (note: average landfill capacity 2.5 million MT MSW waste) in Wisconsin, to establish an approach for estimating the LTC period using field data and PPC funding need. Statistical analysis of time versus concentration data of selected leachate parameters showed that the concentration of most parameters is expected to be at or below the preventive action limit of groundwater and leachate volume will be very low, within 40 years of the LTC period. The gas extraction system may need to be continued for more than 100 years. Due to lack of data no conclusion could be made regarding adequacy of the LTC period for the groundwater monitoring system. The final cover must be maintained for perpetuity. The pilot study shows that although technology is available, the financial liability of maintaining a 'Dry Tomb' design for landfills is significantly higher than commonly perceived. The paper will help landfill professionals to estimate realistic post-closure funding and to develop field-based policies for LTC and PPC of engineered MSW landfills. PMID:25687915

Bagchi, Amalendu; Bhattacharya, Abhik

2015-03-01

291

Study of Swift Heavy Ion Modified Conducting Polymer Composites for Application as Gas Sensor  

PubMed Central

A polyaniline-based conducting composite was prepared by oxidative polymerisation of aniline in a polyvinylchloride (PVC) matrix. The coherent free standing thin films of the composite were prepared by a solution casting method. The polyvinyl chloride-polyaniline composites exposed to 120 MeV ions of silicon with total ion fluence ranging from 1011 to 1013 ions/cm2, were observed to be more sensitive towards ammonia gas than the unirradiated composite. The response time of the irradiated composites was observed to be comparably shorter. We report for the first time the application of swift heavy ion modified insulating polymer conducting polymer (IPCP) composites for sensing of ammonia gas.

Srivastava, Alok; Singh, Virendra; Dhand, Chetna; Kaur, Manindar; Singh, Tejvir; Witte, Karin; Scherer, Ulrich W.

2006-01-01

292

Landfills: Building Them Better  

NSDL National Science Digital Library

Waste disposal has been an ongoing societal problem since medieval times. In this lesson, students learn about the three methods of waste disposal in use by modern communities. They also investigate how engineers design sanitary landfills to prevent leachate from polluting the underlining groundwater.

Integrated Teaching and Learning Program,

293

Assessment of municipal waste compost as a daily cover material for odour control at landfill sites  

Microsoft Academic Search

The ability of municipal waste compost as a daily cover material to reduce the odorous emissions associated with landfill surfaces was investigated. Trials were carried out using landfill gas, a certified sulphurous gas mix and ambient air as a control. Odorous gas was passed through portable test column filled with compost at different densities (590kg\\/m3 and 740kg\\/m3). Gas samples were

Claire Hurst; Philip Longhurst; Simon Pollard; Richard Smith; Bruce Jefferson; Jan Gronow

2005-01-01

294

Dynamic Properties of Municipal Solid Waste in Bioreactor Landfills with Degradation  

Microsoft Academic Search

Bioreactor landfills are operated to enhance refuse decomposition, gas production, and waste stabilization. The major aspect\\u000a of bioreactor landfill operation is the recirculation of collected leachate back through the refuse mass. Due to the presence\\u000a of additional leachate and accelerated decomposition, the characteristics of Municipal Solid Waste (MSW) in bioreactor landfills\\u000a are expected to change. About 50% of the continental

M. S. Hossain; M. A. Haque; L. R. Hoyos

2010-01-01

295

Rare gas isotopic compositions in natural gases of Japan  

NASA Astrophysics Data System (ADS)

Isotopic and elemental compositions of rare gases in various types of gas samples collected in the Japanese Islands were investigated. Excess 3He was found in most samples. Many samples showed a regionally uniform high 3He/ 4He ratio of about 7 times the atmospheric ratio. The He concentrations varied from 0.6 to 1800 ppm, and they were low in CO 2-rich gases and high in N 2-rich gases. Ne isotopic deviations from the atmospheric Ne were detected in most volcanic gases. The deviations and the elemental abundance patterns in volcanic gases can be explained by a mixing between two components, one is mass fractionated rare gases and the other is isotopically atmospheric and is enriched in heavy rare gas elements. Ar was a mixture of mass fractionated Ar, atmospheric Ar and radiogenic Ar, and the contribution of radiogenic 40Ar was small in all samples. Except for He, elemental abundance patterns were progressively enriched in the heavier rare gases relative to the atmosphere. Several samples were highly enriched in Kr and Xe relative to the abundance pattern of dissolution equilibrium of atmospheric rare gases in water. The component which is highly enriched in heavy rare gases may be released from sedimentary materials in the crust.

Nagao, Keisuke; Takaoka, Nobuo; Matsubayashi, Osamu

1981-04-01

296

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

297

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

298

Field assessment of semi-aerobic condition and the methane correction factor for the semi-aerobic landfills provided by IPCC guidelines.  

PubMed

According to IPCC guidelines, a semi-aerobic landfill site produces one-half of the amount of CH4 produced by an equally-sized anaerobic landfill site. Therefore categorizing the landfill type is important on greenhouse gas inventories. In order to assess semi-aerobic condition in the sites and the MCF value for semi-aerobic landfill, landfill gas has been measured from vent pipes in five semi-aerobically designed landfills in South Korea. All of the five sites satisfied requirements of semi-aerobic landfills in 2006 IPCC guidelines. However, the ends of leachate collection pipes which are main entrance of air in the semi-aerobic landfill were closed in all five sites. The CH4/CO2 ratio in landfill gas, indicator of aerobic and anaerobic decomposition, ranged from 1.08 to 1.46 which is higher than the values (0.3-1.0) reported for semi-aerobic landfill sites and is rather close to those (1.0-2.0) for anaerobic landfill sites. The low CH4+CO2% in landfill gas implied air intrusion into the landfill. However, there was no evidence that air intrusion has caused by semi-aerobic design and operation. Therefore, the landfills investigated in this study are difficult to be classified as semi-aerobic landfills. Also MCF of 0.5 may significantly underestimate methane emissions compared to other researches. According to the carbon mass balance analyses, the higher MCF needs to be proposed for semi-aerobic landfills. Consequently, methane emission estimate should be based on field evaluation for the semi-aerobically designed landfills. PMID:25488731

Jeong, Sangjae; Nam, Anwoo; Yi, Seung-Muk; Kim, Jae Young

2015-02-01

299

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.

300

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

301

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

302

LETTER doi:10.1038/nature13000 Change in the chemical composition of infalling gas  

E-print Network

at the centrifugal barrier of the infalling gas (that is, half the centrifugal radius). In fact, the observed maximumLETTER doi:10.1038/nature13000 Change in the chemical composition of infalling gas forming a disk is expected to form7,8 . The interstellar gas, mainly con- sistingofhydrogenmolecules

Cai, Long

303

Estimate of global methane emissions from landfills and open dumps. Final report, January 1992-September 1994  

SciTech Connect

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. CH4 produced by the anaerobic decomposition of waste buried in landfills and open dumps is a significant contributor to global CH4 emissions, with estimates ranging from 10 to 70 Tg/yr. Methods of managing solid waste vary widely, ranging from open dumps and open burning to sanitary landfills with leachate collection systems and LFG control.

Doorn, M.R.J.; Barlaz, M.A.

1995-02-01

304

Landfill methane recovery. Part I: environmental impacts. Final report Sep 80Sep 81  

Microsoft Academic Search

This study was performed to assess the potential environmental and safety impacts of landfill methane recovery. The conclusion of the study is that the range of uses for landfill gas and relative simplicity of the supply process make this technology suitable for investigation by both private industry and public utilities. The environmental and safety issues of most concern are those

R. E. Zimmerman; M. E. Goodkind

1981-01-01

305

Influence of landfill factors on plants and soil fauna—An ecological perspective  

Microsoft Academic Search

An ecological study was conducted on two landfill sites in Hong Kong. Both sites were contaminated by landfill gas and leachate, as indicated by the high concentrations of CH4 and CO2 and the presence of high concentration of NH4-N in the cover soil layer. Their plant diversity and performance, as well as the soil and litter animals, were compared with

Y. S. G. Chan; L. M. Chu; M. H. Wong

1997-01-01

306

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

PubMed

The potential for natural attenuation of volatile organic compounds (VOCs) in landfill covers was investigated in soil microcosms incubated with methane and air, simulating the gas composition in landfill soil covers. Soil was sampled at Skellingsted Landfill at a location emitting methane. In total, 26 VOCs were investigated, including chlorinated methanes, ethanes, ethenes, fluorinated hydrocarbons, and aromatic hydrocarbons. The soil showed a high capacity for methane oxidation resulting in very high oxidation rates of between 24 and 112 microg CH4 g(-1) h(-1). All lower chlorinated compounds were shown degradable, and the degradation occurred in parallel with the oxidation of methane. In general, the degradation rates of the chlorinated aliphatics were inversely related to the chlorine to carbon ratios. For example, in batch experiments with chlorinated ethylenes, the highest rates were observed for vinyl chloride (VC) and lowest rates for trichloroethylene (TCE), while tetrachloroethylene (PCE) was not degraded. Maximal oxidation rates for the halogenated aliphatic compounds varied between 0.03 and 1.7 microg g(-1) h(-1). Fully halogenated hydrocarbons (PCE, tetrachloromethane [TeCM], chlorofluorocarbon [CFC]-11, CFC-12, and CFC-113) were not degraded in the presence of methane and oxygen. Aromatic hydrocarbons were rapidly degraded giving high maximal oxidation rates (0.17-1.4 microg g(-1) h(-1)). The capacity for methane oxidation was related to the depth of oxygen penetration. The methane oxidizers were very active in oxidizing methane and the selected trace components down to a depth of 50 cm below the surface. Maximal oxidation activity occurred in a zone between 15 and 20 cm below the surface, as this depth allowed sufficient supply of both methane and oxygen. Mass balance calculations using the maximal oxidation rates obtained demonstrated that landfill soil covers have a significant potential for not only methane oxidation but also cometabolic degradation of selected volatile organics, thereby reducing emissions to the atmosphere. PMID:14964359

Scheutz, Charlotte; Mosbaek, Hans; Kjeldsen, Peter

2004-01-01

307

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...

308

Phytoremediation of landfill leachate  

SciTech Connect

Leachate emissions from landfill sites are of concern, primarily due to their toxic impact when released unchecked into the environment, and the potential for landfill sites to generate leachate for many hundreds of years following closure. Consequently, economically and environmentally sustainable disposal options are a priority in waste management. One potential option is the use of soil-plant based remediation schemes. In many cases, using either trees (including short rotation coppice) or grassland, phytoremediation of leachate has been successful. However, there are a significant number of examples where phytoremediation has failed. Typically, this failure can be ascribed to excessive leachate application and poor management due to a fundamental lack of understanding of the plant-soil system. On balance, with careful management, phytoremediation can be viewed as a sustainable, cost effective and environmentally sound option which is capable of treating 250 m{sup 3} ha{sup -1} yr{sup -1}. However, these schemes have a requirement for large land areas and must be capable of responding to changes in leachate quality and quantity, problems of scheme establishment and maintenance, continual environmental monitoring and seasonal patterns of plant growth. Although the fundamental underpinning science is well understood, further work is required to create long-term predictive remediation models, full environmental impact assessments, a complete life-cycle analysis and economic analyses for a wide range of landfill scenarios.

Jones, D.L. [School of Agricultural and Forest Sciences, University of Wales, Bangor, Gwynedd LL57 2UW, Wales (United Kingdom)]. E-mail: d.jones@bangor.ac.uk; Williamson, K.L. [School of Agricultural and Forest Sciences, University of Wales, Bangor, Gwynedd LL57 2UW, Wales (United Kingdom); Owen, A.G. [School of Agricultural and Forest Sciences, University of Wales, Bangor, Gwynedd LL57 2UW, Wales (United Kingdom)

2006-07-01

309

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

310

Precipitates in landfill leachate mediated by dissolved organic matters.  

PubMed

Clogging of landfill leachate collection system is so ubiquitous that it causes problems to landfills. Although precipitations of calcite and other minerals have been widely observed, the mechanism of precipitation remains obscure. We examined the clog composition, dissolved organic matters, leachate chemical compositions and the correlation of these variables in view of the precipitation process. It is shown that Dissolved Organic Carbon (DOC) inhibits precipitation of landfill leachate. Using the advanced NICA-Donnan model, the analysis of aqueous chemical reactions between Mg-Ca-DOC-CO2 suggests a good agreement with experimental observations. Calcite and dolomite are both found to be oversaturated in most of the landfill leachate samples. DOC is found to preferentially bind with Mg than Ca, leading to more likely precipitation of Calcite than dolomite from landfill leachate. The NICA-Donnan model gives a reasonable estimation of dolomite saturation index in a wide range of DOC. Modeling confirms the major precipitation mechanism in terms of alkaline earth metal carbonate. Uncertainties in model parameters are discussed with particular focus on DOC composition, functional group types and density concentration and the influential factors. PMID:25661175

Li, Zhenze; Xue, Qiang; Liu, Lei; Li, Jiangshan

2015-04-28

311

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.

312

Landfill closure--sounds easy, doesn`t it?  

SciTech Connect

Closing a landfill can be much more difficult than starting a new one. The owner desires effectiveness and economy, the engineer is provided sketchy background information, and the contractor faces almost certain changed conditions and disputes. The Lake County Landfill was a large municipal waste landfill which operated within an upper middle-class suburban setting in Northeast Ohio. The landfill was located in a complex hydrogeologic regime and covered over 80 acres on a variety of ground conditions. Waste Management of Ohio, Inc. initiated planning and design of landfill closure in 1990 and completed final closure in 1994. The closure route was strewn with pitfalls, obstacles, and hard left turns. Mistakes were made, and duly noted. However, a successful final product has allowed the involved parties to reflect and establish new ground rules for future such endeavors. This paper is a collaborative effort between the owner, design engineer, and construction manager who share their diverse perspectives. Invaluable lessons were learned in the following areas: (1) contractual relationships between the involved parties; (2) the importance of verifying {open_quotes}assumed correct{close_quotes} information (including topography); (3) the interrelations between gas extraction, leachate collection, and sealing; (4) the compromises between sophisticated automated systems and simplicity, and (5) the tradeoffs between over-engineering and field-fitting. Specific engineering examples are combined with general observations, resulting in a guide which the authors and their coworkers will pull off the shelf prior to each future landfill closure project.

Beaudoin, M.R.; Stockman, A.; Fletcher, D.

1995-12-31

313

A finite element simulation of biological conversion processes in landfills  

SciTech Connect

Landfills are the most common way of waste disposal worldwide. Biological processes convert the organic material into an environmentally harmful landfill gas, which has an impact on the greenhouse effect. After the depositing of waste has been stopped, current conversion processes continue and emissions last for several decades and even up to 100 years and longer. A good prediction of these processes is of high importance for landfill operators as well as for authorities, but suitable models for a realistic description of landfill processes are rather poor. In order to take the strong coupled conversion processes into account, a constitutive three-dimensional model based on the multiphase Theory of Porous Media (TPM) has been developed at the University of Duisburg-Essen. The theoretical formulations are implemented in the finite element code FEAP. With the presented calculation concept we are able to simulate the coupled processes that occur in an actual landfill. The model's theoretical background and the results of the simulations as well as the meantime successfully performed simulation of a real landfill body will be shown in the following.

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

2011-04-15

314

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

315

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...

316

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

SciTech Connect

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

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

1998-02-01

317

30 CFR 36.26 - Composition of exhaust gas.  

Code of Federal Regulations, 2013 CFR

...any conditions of engine operation prescribed...air mixture to the engine contains 1.5...of Pittsburgh natural gas. 3 3 Investigation...purposes, Pittsburgh natural gas (containing a...for connecting the engine to MSHA's...

2013-07-01

318

30 CFR 36.26 - Composition of exhaust gas.  

Code of Federal Regulations, 2010 CFR

...any conditions of engine operation prescribed...air mixture to the engine contains 1.5...of Pittsburgh natural gas. 3 3 Investigation...purposes, Pittsburgh natural gas (containing a...for connecting the engine to MSHA's...

2010-07-01

319

30 CFR 36.26 - Composition of exhaust gas.  

Code of Federal Regulations, 2011 CFR

...any conditions of engine operation prescribed...air mixture to the engine contains 1.5...of Pittsburgh natural gas. 3 3 Investigation...purposes, Pittsburgh natural gas (containing a...for connecting the engine to MSHA's...

2011-07-01

320

30 CFR 36.26 - Composition of exhaust gas.  

Code of Federal Regulations, 2012 CFR

...any conditions of engine operation prescribed...air mixture to the engine contains 1.5...of Pittsburgh natural gas. 3 3 Investigation...purposes, Pittsburgh natural gas (containing a...for connecting the engine to MSHA's...

2012-07-01

321

30 CFR 36.26 - Composition of exhaust gas.  

Code of Federal Regulations, 2014 CFR

...any conditions of engine operation prescribed...air mixture to the engine contains 1.5...of Pittsburgh natural gas. 3 3 Investigation...purposes, Pittsburgh natural gas (containing a...for connecting the engine to MSHA's...

2014-07-01

322

Fuel composition effects on natural gas vehicle emissions  

Microsoft Academic Search

Under a contract from DOE`s National Renewable Energy Laboratory (NREL) and support from Brooklyn Union Gas Company (BUG), Northern Illinois Gas Co., the Institute of Gas Technology (IGT) evaluated four state-of-the-art, electronic, closed-loop natural gas vehicle (NGV) conversion systems. The systems included an Impco electronic closed-loop system, Mogas electronic closed-loop system, Stewart and Stevenson`s GFI system, and an Automotive Natural

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

1994-01-01

323

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

324

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...

325

MONITORING APPROACHES FOR BIOREACTOR LANDFILLS  

EPA Science Inventory

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

326

Stabilizing Waste Materials for Landfills  

ERIC Educational Resources Information Center

The test procedures used to evaluate the suitability of landfilled materials of varying stability and to determine the leachate from such materials are reviewed. A process for stabilizing a mixture of sulfur dioxide sludge, fly ash, and bottom ash with lime and other additives for deposition in landfills is detailed. (BT)

Environmental Science and Technology, 1977

1977-01-01

327

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

328

Decomposition of forest products buried in landfills  

SciTech Connect

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

Wang, Xiaoming, E-mail: xwang25@ncsu.edu [Department of Civil, Construction, and Environmental Engineering, Campus Box 7908, North Carolina State University, Raleigh, NC 27695-7908 (United States); Padgett, Jennifer M. [Department of Civil, Construction, and Environmental Engineering, Campus Box 7908, North Carolina State University, Raleigh, NC 27695-7908 (United States); Powell, John S. [Department of Chemical and Biomolecular Engineering, Campus Box 7905, North Carolina State University, Raleigh, NC 27695-7905 (United States); Barlaz, Morton A. [Department of Civil, Construction, and Environmental Engineering, Campus Box 7908, North Carolina State University, Raleigh, NC 27695-7908 (United States)

2013-11-15

329

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...

330

Melt-infiltrated Sic Composites for Gas Turbine Engine Applications  

NASA Technical Reports Server (NTRS)

SiC-SiC ceramic matrix composites (CMCs) manufactured by the slurry -cast melt-infiltration (MI) process are leading candidates for many hot-section turbine engine components. A collaborative program between Goodrich Corporation and NASA-Glenn Research Center is aimed at determining and optimizing woven SiC/SiC CMC performance and reliability. A variety of composites with different fiber types, interphases and matrix compositions have been fabricated and evaluated. Particular focus of this program is on the development of interphase systems that will result in improved intermediate temperature stressed-oxidation properties of this composite system. The effect of the different composite variations on composite properties is discussed and, where appropriate, comparisons made to properties that have been generated under NASA's Ultra Efficient Engine Technology (UEET) Program.

Morscher, Gregory N.; Pujar, Vijay V.

2004-01-01

331

Use of high temperature insulation for ceramic matrix composites in gas turbines  

DOEpatents

A ceramic composition for insulating components, made of ceramic matrix composites, of gas turbines is provided. The composition comprises a plurality of hollow oxide-based spheres of various dimensions, a phosphate binder, and at least one oxide filler powder, whereby the phosphate binder partially fills gaps between the spheres and the filler powders. The spheres are situated in the phosphate binder and the filler powders such that each sphere is in contact with at least one other sphere and the arrangement of spheres is such that the composition is dimensionally stable and chemically stable at a temperature of approximately 1600.degree. C. A stationary vane of a gas turbine comprising the composition of the present invention bonded to the outer surface of the vane is provided. A combustor comprising the composition bonded to the inner surface of the combustor is provided. A transition duct comprising the insulating coating bonded to the inner surface of the transition is provided. Because of abradable properties of the composition, a gas turbine blade tip seal comprising the composition also is provided. The composition is bonded to the inside surface of a shroud so that a blade tip carves grooves in the composition so as to create a customized seal for the turbine blade tip.

Morrison, Jay Alan (Orlando, FL); Merrill, Gary Brian (Pittsburgh, PA); Ludeman, Evan McNeil (New Boston, NH); Lane, Jay Edgar (Murrysville, PA)

2001-01-01

332

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

333

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

1995-01-01

334

GEOSYNTHETIC REINFORCEMENT IN LANDFILL DESIGN: US PERSPECTIVES  

E-print Network

in landfill projects. This is the case in the periphery of landfill sites, which are often constrained site in order to enhance the stability of the southeastern slopes of the OII Landfill Superfund siteGEOSYNTHETIC REINFORCEMENT IN LANDFILL DESIGN: US PERSPECTIVES Jorge G. Zornberg1 , M. ASCE

Zornberg, Jorge G.

335

IMPACT ASSESSMENT OF THE OLD QUESNEL LANDFILL  

E-print Network

List of Figures Site Location/Legal Boundary Old Quesnel Landfill#12;IMPACT ASSESSMENT OF THE OLD QUESNEL LANDFILL FINAL REPORT DOE FRAP 1995-05 Prepared for .....................................2 Schematic of Source Pathway Receptor Model at Old Quesnel Landfill .......4 Landfill Extent

336

Method and apparatus for off-gas composition sensing  

DOEpatents

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

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

1999-01-01

337

Formation of compositionally graded multilayer films by discharge gas flow modulation in magnetron sputtering  

Microsoft Academic Search

A new method to form compositionally graded multilayer films by using a single deposition source has been developed. In this method, the reactive gas flow rate has been changed periodically to form multilayers. As a result, the composition of the multilayer films obtained by this technique changes periodically without any interrupted interfaces. To form multilayers using this technique, a non-linear

E. Kusano; A. Kinbara; I. Kondo

1997-01-01

338

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

339

Gas reservoirs in composite shale-sandstone lithologies: a Rocky Mountain energy frontier  

Microsoft Academic Search

Thick sequences of marine rocks consisting of thin (1 to 5 cm) composite bedsets of sandstone and shale constitute a major part of the Cretaceous sedimentary prism that accumulated in the Western Interior. Today, these rocks include signficant source beds and are locally important reservoirs for natural gas. Because of their large areal extent, immense volume, and ubiquitous gas content,

D. L. Gautier

1983-01-01

340

Selective CO gas detection of SnO 2–Zn 2SnO 4 composite gas sensor  

Microsoft Academic Search

For the selective detection of CO against H2 gas, SnO2–Zn2SnO4 composite-type sensors were fabricated. The surface of the pellet-type composite sensors was coated by CuO after sintering at 1000°C for 3h. The electrical conductivity and the sensitivity of the sensors to reducing gases (200ppm CO and 200ppm H2) were examined by measuring the current–voltage (I–V) characteristics of the composite sensors

Won Jae Moon; Ji Haeng Yu; Gyeong Man Choi

2001-01-01

341

Syngas production from catalytic gasification of waste polyethylene: Influence of temperature on gas yield and composition  

Microsoft Academic Search

The catalytic steam gasification of waste polyethylene (PE) from municipal solid waste (MSW) to produce syngas (H2+CO) with NiO\\/?-Al2O3 as catalyst in a bench-scale downstream fixed bed reactor was investigated. The influence of the reactor temperature on the gas yield, gas composition, steam decomposition, low heating value (LHV), cold gas efficiency and carbon conversion efficiency was investigated at the temperature

Maoyun He; Bo Xiao; Zhiquan Hu; Shiming Liu; Xianjun Guo; Siyi Luo

2009-01-01

342

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

343

Livingston Parish Landfill Methane Recovery Project (Feasibility Study)  

SciTech Connect

The Woodside Landfill is owned by Livingston Parish, Louisiana and is operated under contract by Waste Management of Louisiana LLC. This public owner/private operator partnership is commonplace in the solid waste industry today. The landfill has been in operation since approximately 1988 and has a permitted capacity of approximately 41 million cubic yards. Based on an assumed in-place waste density of 0.94 ton per cubic yard, the landfill could have an expected design capacity of 39.3 million tons. The landfill does have an active landfill gas collection and control system (LFGCCS) in place because it meets the minimum thresholds for the New Source Performance Standards (NSPS). The initial LFGCS was installed prior to 2006 and subsequent phases were installed in 2007 and 2010. The Parish received a grant from the United States Department of Energy in 2009 to evaluate the potential for landfill gas recovery and utilization at the Woodside Landfill. This includes a technical and economic feasibility study of a project to install a landfill gas to energy (LFGTE) plant and to compare alternative technologies. The LFGTE plant can take the form of on-site electrical generation, a direct use/medium Btu option, or a high-Btu upgrade technology. The technical evaluation in Section 2 of this report concludes that landfill gas from the Woodside landfill is suitable for recovery and utilization. The financial evaluations in sections 3, 4, and 5 of this report provide financial estimates of the returns for various utilization technologies. The report concludes that the most economically viable project is the Electricity Generation option, subject to the Parish’s ability and willingness to allocate adequate cash for initial capital and/or to obtain debt financing. However, even this option does not present a solid return: by our estimates, there is a 19 year simple payback on the electricity generation option. All of the energy recovery options discussed in this report economically stressed. The primary reason for this is the recent fundamental shift in the US energy landscape. Abundant supplies of natural gas have put downward pressure on any project that displaces natural gas or natural gas substitutes. Moreover, this shift appears long-term as domestic supplies for natural gas may have been increased for several hundred years. While electricity prices are less affected by natural gas prices than other thermal projects, they are still significantly affected since much of the power in the Entergy cost structure is driven by natural gas-fired generation. Consequently, rates reimbursed by the power company based on their avoided cost structure also face downward pressure over the near and intermediate term. In addition, there has been decreasing emphasis on environmental concerns regarding the production of thermal energy, and as a result both the voluntary and mandatory markets that drive green attribute prices have softened significantly over the past couple of years. Please note that energy markets are constantly changing due to fundamental supply and demand forces, as well as from external forces such as regulations and environmental concerns. At any point in the future, the outlook for energy prices may change and could deem either the electricity generation or pipeline injection project more feasible. This report is intended to serve as the primary background document for subsequent decisions made at Parish staff and governing board levels.

White, Steven

2012-11-15

344

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

PubMed Central

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

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

2013-01-01

345

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

PubMed

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

Giri, Rajiv K; Reddy, Krishna R

2014-03-01

346

New landfill technology for an old landfill`s problems: A case study  

SciTech Connect

There are presently 111 solid waste sites in Indiana where groundwater is being monitored on a regular basis. Solid waste regulations passed in 1989 required leachate collection systems (LCS) in all new landfills. Of the 111 monitored solid waste facilities, only about 20 of them have an LCS, either built into the original design or retrofitted into an old design. Furthermore, 42 solid waste sites are presently under Phase 2 or assessment monitoring (suspected of causing groundwater contamination) and 8 are in corrective action with confirmed groundwater contamination. It is significant that none of these sites with suspected or confirmed groundwater contamination have leachate collection systems. It has been the authors` experience that many old landfills without LCSs have problems with leachate breakouts on sideslopes. However, these same landfills are found to have good natural base liners and a low chance of contaminating groundwater. On the other hand, if an old landfill has no LCS, yet is not experiencing leachate breakouts on the sideslopes, the base liner may be suspect and leachate may be exiting the landfill bottom and into underlying groundwater. This paper presents a case study of an old landfill that, until recently, had no leachate control system. The landfill had experienced significant leachate breakouts on sideslopes except for one particular corner of the fill area.

Bannister, T.A.; Warren, V.L. [EMCON, Indianapolis, IN (United States)

1996-11-01

347

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...

348

LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL  

SciTech Connect

The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 metric tons [tonnes]), sufficient to replicate many heat and compaction characteristics of larger ''full-scale'' landfills. An enhanced demonstration cell has received moisture supplementation to field capacity. This is the maximum moisture waste can hold while still limiting liquid drainage rate to minimal and safely manageable levels. The enhanced landfill module was compared to a parallel control landfill module receiving no moisture additions. Gas recovery has continued for a period of over 4 years. It is quite encouraging that the enhanced cell methane recovery has been close to 10-fold that experienced with conventional landfills. This is the highest methane recovery rate per unit waste, and thus progress toward stabilization, documented anywhere for such a large waste mass. This high recovery rate is attributed to moisture, and elevated temperature attained inexpensively during startup. Economic analyses performed under Phase I of this NETL contract indicate ''greenhouse cost effectiveness'' to be excellent. Other benefits include substantial waste volume loss (over 30%) which translates to extended landfill life. Other environmental benefits include rapidly improved quality and stabilization (lowered pollutant levels) in liquid leachate which drains from the waste.

Don Augenstein

2001-02-01

349

Characterization of thermal properties of municipal solid waste landfills.  

PubMed

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

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

2015-02-01

350

Sanitary landfill groundwater monitoring report  

SciTech Connect

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

Not Available

1993-02-01

351

Where Should the Landfill Go?  

ERIC Educational Resources Information Center

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

Fazio, Rosario P.; McFaden, Dennis

1993-01-01

352

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 R³P-concept : Recycling of Materials, Recovery of Energy, Reclamation of Land and Protection of drinking water supply. . On behalf of the OVAM, ECOREM was assigned to follow-up a pilot case executed on a former landfill, located in Zuienkerke, Flanders. Within this case study some technical tests were carried out on the excavated waste material to investigate the possibilities for a waste to resource conversion. The performance of both on site and off site techniques were evaluated. These testings also contribute to the mapping part of OVAM's research programme on ELFM and reveal more information on the composition of former landfills dating from different era's. In order to recover as many materials as possible, five contractors were assigned to perform separation tests on the bulk material from the Zuienkerke landfill. All used techniques were described, 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

353

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 19–59 days.

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

2003-01-01

354

Recirculation of municipal landfill leachate  

E-print Network

RECIRCULATION OF MUNICIPAL LANDFILL LEACHATE A Thesis by BRIAN JUDE PINKO4ISKI Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1987 Major Subject...: Civil Engineering RECIRCULATION OF MUNICIPAL LANDFILL LEACHATE A Thesis by BRIAN JUDE PINKOWSKI Approved as to style and content by: Charles P. Giammona (Chair of Committee) Roy . Harm, (Member) Kirk W. Brown (Member) Donald A. Maxwel...

Pinkowski, Brian Jude

1987-01-01

355

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

356

Hazardous waste landfill leachate characteristics  

SciTech Connect

Leachate data from 18 commercial hazardous waste landfills or cells were evaluated to determine overall leachate characteristics and parameters that may affect leachate generation and characteristics. The landfills studied have a wide range of practices, none of which are necessarily representative of the most current landfill design, operating or closure practice in the United States. The leachate samples were from landfills that represented varying waste types, waste age, geographic locations and climate. The parameters evaluated included chemical properties, co-disposal of hazardous and municipal solid wastes, climatic conditions, and waste age in the landfills. The leachate samples had been analyzed for 62 volatiles, 107 semi-volatiles, 16 metals, 28 pesticides, herbicides and insecticides, and 17 other chemicals. The results indicate that: (a) the organics in the leachate with high concentrations had high solubilities and low octanol-water coefficients, (b) landfills in arid climates produced less leachate than those in temperate and sub-tropical climates, and (c) leachate production appeared to be related to use of a cap or cover.

Pavelka, C. (Woodward-Clyde Consultants, Maryland Heights, MO (United States)); Loehr, R.C. (Univ. of Texas, Austin, TX (United States). Environmental and Water Resources Engineering Program); Haikola, B. (Remediation Technologies, Inc., Austin, TX (United States))

1993-01-01

357

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

358

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

USGS Publications Warehouse

IT is widely accepted that natural gas is formed from thermal decomposition of both oil in reservoirs and, to a lesser extent, the organic matter in shales from which the oil was derived1-6. But laboratory pyrolysis experiments on shales do not reproduce the methane-rich composition typical of most gas reservoirs7, leading to suggestions7 that other mechanisms, such as transition-metal catalysis, may be important. The discrepancy might, however, instead arise because gas (and oil) deposits have migrated from their source rocks, so that the reservoir composition might not be representative of the composition in the source rocks where the hydrocarbons were generated. To address this question, we have analysed gas samples coproduced with oils directly from a source rock (the Bakken shales, North Dakota, USA) where the local geology has prevented significant hydrocarbon migration. The methane contents of these Bakken-shale gases are much lower than that of conventional gas reservoirs, but are consistent with that from pyrolysis experiments8,9 on these shales. Thus, because these Bakken gases form with (rather than from) oils, we argue that compositional differences between gases from source rocks and conventional gas deposits result from fractionation processes occurring after hydrocarbon expulsion from the source rock.

Price, L.C.; Schoell, M.

1995-01-01

359

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

360

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

PubMed

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

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

2011-05-01

361

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

362

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 Quirós, Yara Bernaldo; González-Diaz, Oscar; Arbelo, Manuel; Sierra, Eva; Sacchini, Simona; Fernández, Antonio

2012-01-01

363

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...

364

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

PubMed

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

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

2015-02-01

365

Effects of natural gas composition on ignition delay under diesel conditions  

SciTech Connect

Effects of variations in natural gas composition on the 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 = 1,150 K), 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. A computational model, incorporating detailed chemical kinetics of oxidation of methane, ethane, propane and other small hydrocarbons was used to predict the influences of fuel composition on ignition, focusing on the four fuel types considered in the experimental study. Numerically predicted variations in ignition delay as a function of natural gas composition agreed with these measurements. The model results are used to interpret the kinetic factors responsible for the observations.

Naber, J.D.; Siebers, D.L. (Sandia National Labs., Livermore, CA (United States). Combustion Research Facility); 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))

1994-11-01

366

Design, Build and Test Your Own Landfill  

NSDL National Science Digital Library

Students design and build model landfills using materials similar to those used by engineers for full-scale landfills. Their completed small-size landfills are "rained" on and subjected to other erosion processes. The goal is to create landfills that hold the most garbage, minimize the cost to build and keep trash and contaminated water inside the landfill to prevent it from causing environmental damage. Teams create designs within given budgets, test the landfills' performance, and graph and compare designs for capacity, cost and performance.

2014-09-18

367

Reactant gas composition for fuel cell potential control  

DOEpatents

A fuel cell (10) system in which a nitrogen (N.sub.2) gas is used on the anode section (11) and a nitrogen/oxygen (N.sub.2 /O.sub.2) gaseous mix is used on the cathode section (12) to maintain the cathode at an acceptable voltage potential during adverse conditions occurring particularly during off-power conditions, for example, during power plant shutdown, start-up and hot holds. During power plant shutdown, the cathode section is purged with a gaseous mixture of, for example, one-half percent (0.5%) oxygen (O.sub.2) and ninety-nine and a half percent (99.5%) nitrogen (N.sub.2) supplied from an ejector (21) bleeding in air (24/28) into a high pressure stream (27) of nitrogen (N.sub.2) as the primary or majority gas. Thereafter the fuel gas in the fuel processor (31) and the anode section (11) is purged with nitrogen gas to prevent nickel (Ni) carbonyl from forming from the shift catalyst. A switched dummy electrical load (30) is used to bring the cathode potential down rapidly during the start of the purges. The 0.5%/99.5% O.sub.2 /N.sub.2 mixture maintains the cathode potential between 0.3 and 0.7 volts, and this is sufficient to maintain the cathode potential at 0.3 volts for the case of H.sub.2 diffusing to the cathode through a 2 mil thick electrolyte filled matrix and below 0.8 volts for no diffusion at open circuit conditions. The same high pressure gas source (20) is used via a "T" juncture ("T") to purge the anode section and its associated fuel processor (31).

Bushnell, Calvin L. (Glastonbury, CT); Davis, Christopher L. (Tolland, CT)

1991-01-01

368

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

369

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

370

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

371

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

PubMed

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

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

2014-03-01

372

Autoresonant-spectrometric determination of the residual gas composition in the ALPHA experiment apparatus  

SciTech Connect

Knowledge of the residual gas composition in the ALPHA experiment apparatus is important in our studies of antihydrogen and nonneutral plasmas. A technique based on autoresonant ion extraction from an electrostatic potential well has been developed that enables the study of the vacuum in our trap. Computer simulations allow an interpretation of our measurements and provide the residual gas composition under operating conditions typical of those used in experiments to produce, trap, and study antihydrogen. The methods developed may also be applicable in a range of atomic and molecular trap experiments where Penning-Malmberg traps are used and where access is limited.

Amole, C.; Capra, A.; Menary, S. [Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3 (Canada); Ashkezari, M. D.; Hayden, M. E. [Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Baquero-Ruiz, M.; Chapman, S.; Little, A.; Povilus, A.; So, C.; Turner, M. [Department of Physics, University of California, Berkeley, California 94720-7300 (United States); Bertsche, W. [Department of Physics, Swansea University, Swansea SA2 8PP (United Kingdom); School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom and The Cockcroft Institute, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Butler, E. [Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Cesar, C. L.; Silveira, D. M. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972 (Brazil); Charlton, M.; Eriksson, S.; Isaac, C. A.; Madsen, N.; Napoli, S. C. [Department of Physics, Swansea University, Swansea SA2 8PP (United Kingdom); Collaboration: ALPHA Collaboration; and others

2013-06-15

373

Effect of fuel gas composition on appliance performance. Topical report Jul 78-Dec 82  

SciTech Connect

Burner performance with various fuel gases has been related to gas composition in terms of flame characteristics, such as lifting flames, yellow tipping and flashback for simulated natural gases and peak-shaving gases. Variations in gas compositions of these gases do not appear to notably affect efficiences of residential forced-air furnaces, hot water boilers, water heaters and ranges, or temperatures of ignition system components or appliance burners. Data have been obtained on emissions of CO/sub 2/, CO, NO and NO/sub 2/ in combustion products of simulated natural and peak-shaving gases.

Griffiths, J.C.; Connelly, S.M.; DeRemer, R.B.

1982-12-01

374

Supercritical water oxidation of landfill leachate  

SciTech Connect

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

Wang Shuzhong, E-mail: s_z_wang@yahoo.cn [School of Energy and Power Engineering of Xi' an Jiao Tong University, Xi'an 710049 (China); Guo Yang [School of Energy and Power Engineering of Xi' an Jiao Tong University, Xi'an 710049 (China); Chen Chongming [Hebei Electric Power Research Institute, Shijizhuang, Hebei 050021 (China); Zhang Jie; Gong Yanmeng; Wang Yuzhen [School of Energy and Power Engineering of Xi' an Jiao Tong University, Xi'an 710049 (China)

2011-09-15

375

Variations in dissolved gas compositions of reservoir fluids from the Coso geothermal field  

SciTech Connect

Gas concentrations and ratios in 110 analyses of geothermal fluids from 47 wells in the Coso geothermal system illustrate the complexity of this two-phase reservoir in its natural state. Two geographically distinct regions of single-phase (liquid) reservoir are present and possess distinctive gas and liquid compositions. Relationships in soluble and insoluble gases preclude derivation of these waters from a common parent by boiling or condensation alone. These two regions may represent two limbs of fluid migration away from an area of two-phase upwelling. During migration, the upwelling fluids mix with chemically evolved waters of moderately dissimilar composition. CO{sub 2} rich fluids found in the limb in the southeastern portion of the Coso field are chemically distinct from liquids in the northern limb of the field. Steam-rich portions of the reservoir also indicate distinctive gas compositions. Steam sampled from wells in the central and southwestern Coso reservoir is unusually enriched in both H{sub 2}S and H{sub 2}. Such a large enrichment in both a soluble and insoluble gas cannot be produced by boiling of any liquid yet observed in single-phase portions of the field. In accord with an upflow-lateral mixing model for the Coso field, at least three end-member thermal fluids having distinct gas and liquid compositions appear to have interacted (through mixing, boiling and steam migration) to produce the observed natural state of the reservoir.

Williams, Alan E.; Copp, John F.

1991-01-01

376

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

377

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=1×0.5, HCl/SO2=0.2×0.1 and H2O/SO2=60×30 without clear contrast during the high and low flux periods. The CO2/SO2 ratios obtained based on a single day data tend to 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

378

Landfills as sources of polyfluorinated compounds, polybrominated diphenyl ethers and musk fragrances to ambient air  

NASA Astrophysics Data System (ADS)

In order to investigate landfills as sources of polyfluorinated compounds (PFCs), polybrominated diphenyl ethers (PBDEs) and synthetic musk fragrances to the atmosphere, air samples were simultaneously taken at two landfills (one active and one closed) and two reference sites using high volume air samplers. Contaminants were accumulated on glass fiber filters (particle phase) and PUF/XAD-2/PUF cartridges (gas phase), extracted by methyl-tert butyl ether/acetone (neutral PFCs), methanol (ionic PFCs) or hexane/acetone (PBDEs, musk fragrances), and detected by GC-MS (neutral PFCs, PBDEs, musk fragrances) or HPLC-MS/MS (ionic PFCs). Total concentrations ranged from 84 to 706 pg m -3 (volatile PFCs, gas phase), from gas + particle phase) and from 1 to 11 pg m -3 (PBDEs, gas + particle phase). Observed sum concentrations of PFCs and synthetic musk fragrances and partly PBDE concentrations were elevated at landfill sites compared to corresponding reference sites. Concentrations determined at the active landfill were higher than those of the inactive landfill. Overall, landfills can be regarded as a source of synthetic musk fragrances, several PFCs and potentially of PBDEs to ambient air.

Weinberg, Ingo; Dreyer, Annekatrin; Ebinghaus, Ralf

2011-02-01

379

Characterization of uncertainty in estimation of methane collection from select u.s. Landfills.  

PubMed

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

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

2015-02-01

380

Melt Infiltrated Ceramic Matrix Composites for Shrouds and Combustor Liners of Advanced Industrial Gas Turbines  

Microsoft Academic Search

This report covers work performed under the Advanced Materials for Advanced Industrial Gas Turbines (AMAIGT) program by GE Global Research and its collaborators from 2000 through 2010. A first stage shroud for a 7FA-class gas turbine engine utilizing HiPerComp{reg_sign}* ceramic matrix composite (CMC) material was developed. The design, fabrication, rig testing and engine testing of this shroud system are described.

Gregory Corman; Krishan Luthra; Jill Jonkowski; Joseph Mavec; Paul Bakke; Debbie Haught; Merrill Smith

2011-01-01

381

Using poly( N,N-dimethylaminoethyl methacrylate)\\/polyacrylonitrile composite membranes for gas dehydration and humidification  

Microsoft Academic Search

The transport of water vapor through a composite membrane consisting of hydrophilic poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) as the active layer and polyacrylonitrile (PAN) as the substrate was investigated, and the performance of the membrane for gas dehydration and humidification applications was evaluated. For gas dehydration, methane\\/water vapor mixtures were used as feed and vacuum was applied on the downstream side. The

Jennifer Runhong Du; Li Liu; Amit Chakma; Xianshe Feng

2010-01-01

382

Central Appalachian basin natural gas database: distribution, composition, and origin of natural gases  

USGS Publications Warehouse

The U.S. Geological Survey (USGS) has compiled a database consisting of three worksheets of central Appalachian basin natural gas analyses and isotopic compositions from published and unpublished sources of 1,282 gas samples from Kentucky, Maryland, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. The database includes field and reservoir names, well and State identification number, selected geologic reservoir properties, and the composition of natural gases (methane; ethane; propane; butane, iso-butane [i-butane]; normal butane [n-butane]; iso-pentane [i-pentane]; normal pentane [n-pentane]; cyclohexane, and hexanes). In the first worksheet, location and American Petroleum Institute (API) numbers from public or published sources are provided for 1,231 of the 1,282 gas samples. A second worksheet of 186 gas samples was compiled from published sources and augmented with public location information and contains carbon, hydrogen, and nitrogen isotopic measurements of natural gas. The third worksheet is a key for all abbreviations in the database. The database can be used to better constrain the stratigraphic distribution, composition, and origin of natural gas in the central Appalachian basin.

Roman-Colon, Yomayra A.; Ruppert, Leslie F.

2015-01-01

383

Impact of changes in barometric pressure on landfill methane emission  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

384

Analysis of exhaust gas composition of internal combustion engines using liquefied petroleum gas  

Microsoft Academic Search

The problems of implementation of liquefied petroleum gas (LPG) supply systems are related with the fact that they are alternative systems used in engines constructed and optimized for work with other kinds of fuel. So assemblers of the systems have to evaluate power losses and at the same time ecological requirements. The experiment is devoted to the analysis of gas

Saulius Mockus; Jonas Sapragonas; Agnius Stonys; Saugirdas Pukalskas

2006-01-01

385

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

386

Effect of geothermal pore-pressure conditions and natural gas composition on in situ natural gas hydrate occurrences, North Slope, Alaska  

Microsoft Academic Search

The factors controlling the distribution of natural gas hydrates (solid compounds composed of natural gas and water) in the earth include mean annual ground temperatures, geothermal gradients, subsurface pressure conditions, gas composition, and pore-fluid salinity. A thorough analysis of the effect of these parameters on thickness and depth of hydrate stability zones has been conducted. A thermodynamic model has been

S. P. Godbole; V. A. Kamath

1985-01-01

387

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

388

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

389

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

NASA Astrophysics Data System (ADS)

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

Xu, Xiongwen; Liu, Jinping; Cao, Le

2014-01-01

390

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

391

Ceramic composite liner material for gas turbine combustors  

NASA Technical Reports Server (NTRS)

Advanced commercial and military gas turbine engines may operate at combustor outlet temperatures in excess of 1920 K (3000 F). At these temperatures combustors liners experience extreme convective and radiative heat fluxes. The ability of a plasma sprayed ceramic coating to reduce liner metal temperature has been recognized. However, the brittleness of the ceramic layer and the difference in thermal expansion with the metal substrate has caused cracking, spalling and some separation of the ceramic coating. Research directed at turbine tip seals (or shrouds) has shown the advantage of applying the ceramic to a compliant metal pad. This paper discusses recent studies of applying ceramics to combustor liners in which yttria stabilized zirconia plasma sprayed on compliant metal substrates which were exposed to near stoichiometric combustion, presents performance and durability results, and describes a conceptual design for an advanced, small gas turbine combustor. Test specimens were convectively cooled or convective-transpiration cooled and were evaluated in a 10 cm square flame tube combustor at inlet air temperatures of 533 K (500 F) and at a pressure of 0.5 MPa (75 psia). The ceramics were exposed to flame temperatures in excess of 2000 K (3320 F). Results appear very promising with all 30 specimens surviving a screening test and one of two specimens surviving a cyclic durability test.

Ercegovic, D. B.; Walker, C. L.; Norgren, C. T.

1984-01-01

392

Control of hydrogen sulfide emissions using autotrophic denitrification landfill biocovers: engineering applications  

Microsoft Academic Search

Hydrogen sulfide (H2S) emitted from construction and demolition waste landfills has received increasing attention. Besides its unpleasant odor,\\u000a longterm exposure to a very low concentration of H2S can cause a public health issue. In the case of construction and demolition (C&D) waste landfills, where gas collection\\u000a systems are not normally required, the generated H2S is typically not controlled and the

Daoroong Sungthong; Debra R. Reinhart

2011-01-01

393

Methane and carbon dioxide emissions from Shan-Chu-Ku landfill site in northern Taiwan  

Microsoft Academic Search

To investigate the methane and carbon dioxide emissions from landfill, samples were taken of material up to 5 years old from Shan-Chu-Ku landfill located in the northern part of Taiwan. Atmospheric concentrations of carbon dioxide, methane and nitrous oxide ranged from 310 to 530, 2.64 to 20.16 and 0.358 to 1.516 ppmv with the measurement of gas-type open-path Fourier transform

Ullas Hegde; Tsan-Chang Chang; Shang-Shyng Yang

2003-01-01

394

BIOREACTOR LANDFILLS, THEORETICAL ADVANTAGES AND RESEARCH CHALLENGES  

EPA Science Inventory

Bioreactor landfills are municipal solid waste landfills that utilize bulk liquids in an effort to accelerate solid waste degradation. There are few potential benefits for operating a MSW landfill as a bioreactor. These include leachate treatment and management, increase in the s...

395

RECLAMATION EFFORTS AT THE LOCKWOOD LANDFILL STATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

The reclamation of disturbed arid rangelands is a monumental task under the best of conditions. The Lockwood Landfill located 17 km east of Reno, Nevada is a Regional Landfill of some 8800 ha in area. This landfill services all of northern Nevada as well as much of northern California. Returning la...

396

Photovoltaic olar nergy Development on Landfills  

E-print Network

of a selfballasting photovoltaic solar racking system will affect a closed landfills dirt cap. The effects experiment wherein single racks with photovoltaic modules will be placed on a landfill cap on landfills. The goals of this project are to: · Place the racking systems on top of a closed, capped

397

LANDFILL AIR EMISSIONS ESTIMATION MODEL USER'S MANUAL  

EPA Science Inventory

The document is a user's guide for the computer program, "Landfill Air Emissions Estimation Model." It provides step-by-step guidance for using the program to estimate landfill air emissions. The purpose of this program is to aid local and state agencies in estimating landfill ai...

398

FIELD VERIFICATION OF HELP MODEL FOR LANDFILLS  

EPA Science Inventory

Long-term simulations of 17 landfill cells from six sites are performed using the Hydrologic Evaluation of Landfill Performance (HELP) computer model. esults are compared with field data from a variety of landfills to verify the model and to identify shortcomings. he sites are lo...

399

MEASUREMENT OF PERSISTENT ORGANIC POLLUTANTS IN LANDFILL  

E-print Network

sites: site A has two landfill zones: the old one ­ K1 - received untreated MSW until 2006; the newMEASUREMENT 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

Paris-Sud XI, Université de

400

Sustainable treatment of landfill leachate  

NASA Astrophysics Data System (ADS)

Landfill leachate is a complex liquid that contains excessive concentrations of biodegradable and non-biodegradable products including organic matter, phenols, ammonia nitrogen, phosphate, heavy metals, and sulfide. If not properly treated and safely disposed, landfill leachate could be an impending source to surface and ground water contamination as it may percolate throughout soils and subsoils, causing adverse impacts to receiving waters. Lately, various types of treatment methods have been proposed to alleviate the risks of untreated leachate. However, some of the available techniques remain complicated, expensive and generally require definite adaptation during process. In this article, a review of literature reported from 2008 to 2012 on sustainable landfill leachate treatment technologies is discussed which includes biological and physical-chemical techniques, respectively.

Kamaruddin, Mohamad Anuar; Yusoff, Mohd. Suffian; Aziz, Hamidi Abdul; Hung, Yung-Tse

2014-03-01

401

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

402

Composite Matrix Cooling Scheme for Small Gas Turbine Combustors  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

403

Development of ceramic composite hot-gas filters  

SciTech Connect

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

Judkins, R.R.; Stinton, D.P. [Oak Ridge National Lab., TN (United States); Smith, R.G.; Fischer, E.M.; Eaton, J.H.; Weaver, B.L.; Kahnke, J.L.; Pysher, D.J. [3M Co., St. Paul, MN (United States)

1995-04-01

404

Mass Spectrometric Measurements of the Neutral Gas Composition of the Thermosphere and Exosphere of Venus  

Microsoft Academic Search

The neutral gas composition and density in the thermosphere of Venus is being measured with a quadrupole mass spectrometer on the Pioneer Venus orbiter. Data are obtained near periapsis once per day approximately 150-250 km above the surface. The principal gases in the thermosphere are CO2, CO, N2, O, N, and He. Atomic oxygen is the major constituent above 155

H. B. Niemann; W. T. Kasprzak; A. E. Hedin; D. M. Hunten; N. W. Spencer

1980-01-01

405

Seawater subduction controls the heavy noble gas composition of the mantle.  

PubMed

The relationship between solar volatiles and those now in the Earth's atmosphere and mantle reservoirs provides insight into the processes controlling the acquisition of volatiles during planetary accretion and their subsequent evolution. Whereas the light noble gases (helium and neon) in the Earth's mantle preserve a solar-like isotopic composition, heavy noble gases (argon, krypton and xenon) have an isotopic composition very similar to that of the modern atmosphere, with radiogenic and (in the case of xenon) solar contributions. Mantle noble gases in a magmatic CO2 natural gas field have been previously corrected for shallow atmosphere/groundwater and crustal additions. Here we analyse new data from this field and show that the elemental composition of non-radiogenic heavy noble gases in the mantle is remarkably similar to that of sea water. We challenge the popular concept of a noble gas 'subduction barrier'--the convecting mantle noble gas isotopic and elemental composition is explained by subduction of sediment and seawater-dominated pore fluids. This accounts for approximately 100% of the non-radiogenic argon and krypton and 80% of the xenon. Approximately 50% of the convecting mantle water concentration can then be explained by this mechanism. Enhanced recycling of subducted material to the mantle plume source region then accounts for the lower ratio of radiogenic to non-radiogenic heavy noble gas isotopes and higher water content of plume-derived basalts. PMID:16688169

Holland, Greg; Ballentine, Chris J

2006-05-11

406

Seawater subduction controls the heavy noble gas composition of the mantle  

NASA Astrophysics Data System (ADS)

The relationship between solar volatiles and those now in the Earth's atmosphere and mantle reservoirs provides insight into the processes controlling the acquisition of volatiles during planetary accretion and their subsequent evolution. Whereas the light noble gases (helium and neon) in the Earth's mantle preserve a solar-like isotopic composition, heavy noble gases (argon, krypton and xenon) have an isotopic composition very similar to that of the modern atmosphere, with radiogenic and (in the case of xenon) solar contributions. Mantle noble gases in a magmatic CO2 natural gas field have been previously corrected for shallow atmosphere/groundwater and crustal additions. Here we analyse new data from this field and show that the elemental composition of non-radiogenic heavy noble gases in the mantle is remarkably similar to that of sea water. We challenge the popular concept of a noble gas `subduction barrier'-the convecting mantle noble gas isotopic and elemental composition is explained by subduction of sediment and seawater-dominated pore fluids. This accounts for ~100% of the non-radiogenic argon and krypton and 80% of the xenon. Approximately 50% of the convecting mantle water concentration can then be explained by this mechanism. Enhanced recycling of subducted material to the mantle plume source region then accounts for the lower ratio of radiogenic to non-radiogenic heavy noble gas isotopes and higher water content of plume-derived basalts.

Holland, Greg; Ballentine, Chris J.

2006-05-01

407

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

408

Composition and Properties of Coal Tar DNAPLs at Former Manufactured Gas Plants  

Microsoft Academic Search

Coal tar is a persistent source of groundwater contamination in the subsurface at many former manufactured gas plants (MGPs). Remediation of coal tar remains a significant environmental challenge due to its complex chemical composition, existence as a dense non-aqueous phase liquid (DNAPL), and tendency to alter the wettability of porous media systems. Changes in wettability are believed to occur due

P. S. Birak; S. C. Hauswirth; D. A. Williams; J. A. Pedit; C. T. Miller

2007-01-01

409

Impact of Fly Ash Composition on Mercury Speciation in Simulated Flue Gas  

Microsoft Academic Search

The impact of different fly ash samples on mercury speciation in simulated flue gas at 140 °C was evaluated in this study. Experiments were conducted in a fixed bed reactor to determine the impact of fly ash morphological characteristics and chemical composition on mercury up-take and oxidation. No homogeneous mercury oxidation was observed at 140 °C. Mercury uptake tests with

Ravi Bhardwaj; Xihua Chen; Radisav D. Vidic; Barry Lefer; Jochen Stutz; Jack Dibb; Robert Griffin; William Brune; Maxwell Shauck; Martin Buhr; Philip Lupo; Elaine Symanski; John Richards; Todd Brozell; Charles Rea; Geoff Boraston; John Hayden; Alberto Escrig; Eliseo Monfort; Irina Celades; Xavier Querol; Fulvio Amato; María Minguillon; Philip Hopke; Naresh Kumar; Veronica Nixon; Kaushik Sinha; Xiaosen Jiang; Sarah Ziegenhorn; Thomas Peters; Xianghui Nie; Guo Huang; Yongping Li; Yung-Chen Yao; Jiun-Horng Tsai; Hui-Fen Ye; Hung-Lung Chiang; Ami Zota; Robert Willis; Rebecca Jim; Gary Norris; James Shine; Rachelle Duvall; Laurel Schaider; John Spengler; Hai Zhang; Raymond Hoff; Jill Engel-Cox; Junming Wang; April Hiscox; David Miller; Thomas Meyer; Ted Sammis

2009-01-01

410

Acceleration of aged-landfill stabilization by combining partial nitrification and leachate recirculation: a field-scale study.  

PubMed

Leachate recirculation for rapid landfill stabilization can result in the accumulation of high-strength ammonium. An on-site sequencing batch reactor (SBR) was therefore, applied to oxidize the ammonium to nitrite, which was then recirculated to the landfill for denitrification to nitrogen gas. At relatively higher ammonium levels, nitrite accumulated well in the SBR; the nitrite was denitrified stably in the landfill, despite an insufficient biodegradable carbon source in the leachate. As the leachate was recirculated, the methane and carbon dioxide contents produced from the landfill fluctuated, implying that the organic acids and hydrogen produced in the acid production phase acted as the carbon source for denitrification in the landfill. Leachate recirculation combined with ex-situ partial nitrification of the leachate may enhance the biodegradation process by: (a) removing the nitrogen that is contained with the leachate, and (b) accelerating landfill stabilization, because the biodegradation efficiency of landfill waste is increased by supplying sufficient moisture and its byproducts are used as the carbon source for denitrification. In addition, partial nitrification using an SBR has advantages for complete denitrification in the landfill, since the available carbon source is in short supply in aged landfills. PMID:25531070

Chung, Jinwook; Kim, Seungjin; Baek, Seungcheon; Lee, Nam-Hoon; Park, Seongjun; Lee, Junghun; Lee, Heechang; Bae, Wookeun

2015-03-21

411

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

412

Effect of therapeutic doses of optical radiation on gas composition of venous blood  

NASA Astrophysics Data System (ADS)

We have studied the effect of in vivo irradiation of blood by radiation at different wavelengths (254 nm, 632.8 nm, and 670 nm), which can be absorbed by blood, on the absorption spectra and gas composition of venous blood for individual patients. We have determined the differences in short-term and long-term changes in both spectral characteristics and the gas composition of blood induced by irradiation. During and immediately after irradiation, for all the patients we observed an increase in the partial pressure of oxygen and a decrease in the partial pressure of carbon dioxide in venous blood. After irradiation was completed, the changes in the partial pressures of blood gases were different for different patients: the gas pressures both increased and decreased, depending on the photo-induced changes in the level of hemoglobin oxygen saturation in venous blood.

Zalesskaya, G. A.; Laskina, O. V.

2013-05-01

413

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

NASA Astrophysics Data System (ADS)

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

Bross, David H.; Peterson, Kirk A.

2014-12-01

414

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

PubMed

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

Bross, David H; Peterson, Kirk A

2014-12-28

415

Venus lower atmospheric composition: analysis by gas chromatography.  

PubMed

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

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

1979-02-23

416

Chemically designed Pt/PPy nano-composite for effective LPG gas sensor  

NASA Astrophysics Data System (ADS)

Simultaneous in situ reduction of hexachloroplatinic acid by the amine group in the pyrrole monomer and oxidation of pyrrole to form polypyrrole (PPy) was examined. The reactions were performed at various temperatures to understand the degree of reduction of platinum precursor as well as doping of polypyrrole with Pt(ii) chloro-complex. Spectroscopic images revealed different morphologies for the Pt/PPy nano-composite prepared at various temperatures. The as-prepared Pt/PPy nano-composite samples were tested for their ability to sense liquefied petroleum gas (LPG) which resulted in excellent sensing at relatively low temperature. The porous nature and ohmic contact between the PPy and platinum nanoparticles makes the as-prepared Pt/PPy nano-composite highly useful for sensors as well as electronic applications.Simultaneous in situ reduction of hexachloroplatinic acid by the amine group in the pyrrole monomer and oxidation of pyrrole to form polypyrrole (PPy) was examined. The reactions were performed at various temperatures to understand the degree of reduction of platinum precursor as well as doping of polypyrrole with Pt(ii) chloro-complex. Spectroscopic images revealed different morphologies for the Pt/PPy nano-composite prepared at various temperatures. The as-prepared Pt/PPy nano-composite samples were tested for their ability to sense liquefied petroleum gas (LPG) which resulted in excellent sensing at relatively low temperature. The porous nature and ohmic contact between the PPy and platinum nanoparticles makes the as-prepared Pt/PPy nano-composite highly useful for sensors as well as electronic applications. Electronic supplementary information (ESI) available: FT-IR spectra of Pt/PPy nano-composite prepared at 150 °C (NB). Thermal analysis (TGA and DSC) of Pt/PPy composite prepared at 150 °C (NB) and EDAX analysis of NA, NB and NC samples to deduce the elemental composition of the samples. See DOI: 10.1039/c3nr05375j

Gaikwad, Namrata; Bhanoth, Sreenu; More, Priyesh V.; Jain, G. H.; Khanna, P. K.

2014-02-01

417

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

418

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

419

Eukaryotic Diversity in an Anaerobic Aquifer Polluted with Landfill Leachate?  

PubMed Central

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 (Banisveld, The Netherlands). The microeukaryotic community at a depth of 1 to 5 m below the surface along a transect downgradient (21 to 68 m) from the landfill and at a clean reference location was diverse. Fungal sequences dominated most clone libraries. The fungal diversity was high, and most sequences were sequences of yeasts of the Basidiomycota. Sequences of green algae (Chlorophyta) were detected in parts of the aquifer close (<30 m) to the landfill. The bacterium-predating nanoflagellate Heteromita globosa (Cercozoa) was retrieved in enrichments, and its sequences dominated the clone library derived from the polluted aquifer at a depth of 5 m at a location 21 m downgradient from the landfill. The number of culturable eukaryotes ranged from 102 to 103 cells/g sediment. Culture-independent quantification revealed slightly higher numbers. Groundwater mesofauna was not detected. We concluded that the food chain in this polluted aquifer is short and consists of prokaryotes and fungi as decomposers of organic matter and protists as primary consumers of the prokaryotes. PMID:18469120

Brad, Traian; Braster, Martin; van Breukelen, Boris M.; van Straalen, Nico M.; Röling, Wilfred F. M.

2008-01-01

420

A new economic instrument for financing accelerated landfill aftercare.  

PubMed

The key aspects of landfill operation that remain unresolved are the extended timescale and uncertain funding of the post-closure period. This paper reviews the topic and proposes an economic instrument to resolve the unsustainable nature of the current situation. Unsustainability arises from the sluggish degradation of organic material and also the slow flushing of potential pollutants that is exacerbated by low-permeability capping. A landfill tax or aftercare provision rebate is proposed as an economic instrument to encourage operators to actively advance the stabilization of landfilled waste. The rebate could be accommodated within existing regulatory and tax regimes and would be paid for: (i) every tonne of nitrogen (or other agreed leachate marker) whose removal is advanced via the accelerated production and extraction of leachate; (ii) every tonne of non-commercially viable carbon removed via landfill gas collection and treatment. The rebates would be set at a level that would make it financially attractive to operators and would encourage measures such as leachate recirculation, in situ aeration, and enhanced flushing. Illustrative calculations suggest that a maximum rebate of up to ?€50/tonne MSW would provide an adequate incentive. PMID:24768257

Beaven, R P; Knox, K; Gronow, J R; Hjelmar, O; Greedy, D; Scharff, H