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Sample records for biogenic methane production

  1. Enhancement of Biogenic Coalbed Methane Production and Back Injection of Coalbed Methane Co-Produced Water

    SciTech Connect

    Song Jin

    2007-05-31

    Biogenic methane is a common constituent in deep subsurface environments such as coalbeds and oil shale beds. Coalbed methane (CBM) makes significant contributions to world natural gas industry and CBM production continues to increase. With increasing CBM production, the production of CBM co-produced water increases, which is an environmental concern. This study investigated the feasibility in re-using CBM co-produced water and other high sodic/saline water to enhance biogenic methane production from coal and other unconventional sources, such as oil shale. Microcosms were established with the selected carbon sources which included coal, oil shale, lignite, peat, and diesel-contaminated soil. Each microcosm contained either CBM coproduced water or groundwater with various enhancement and inhibitor combinations. Results indicated that the addition of nutrients and nutrients with additional carbon can enhance biogenic methane production from coal and oil shale. Methane production from oil shale was much greater than that from coal, which is possibly due to the greater amount of available Dissolved Organic Carbon (DOC) from oil shale. Inconclusive results were observed from the other sources since the incubation period was too low. WRI is continuing studies with biogenic methane production from oil shale.

  2. Sources of biogenic methane to form marine gas hydrates: In situ production or upward migration?

    SciTech Connect

    Paull, C.K.; Ussler, W. III; Borowski, W.S.

    1993-09-01

    Potential sources of biogenic methane in the Carolina Continental Rise -- Blake Ridge sediments have been examined. Two models were used to estimate the potential for biogenic methane production: (1) construction of sedimentary organic carbon budgets, and (2) depth extrapolation of modern microbial production rates. While closed-system estimates predict some gas hydrate formation, it is unlikely that >3% of the sediment volume could be filled by hydrate from methane produced in situ. Formation of greater amounts requires migration of methane from the underlying continental rise sediment prism. Methane may be recycled from below the base of the gas hydrate stability zone by gas hydrate decomposition, upward migration of the methane gas, and recrystallization of gas hydrate within the overlying stability zone. Methane bubbles may also form in the sediment column below the depth of gas hydrate stability because the methane saturation concentration of the pore fluids decreases with increasing depth. Upward migration of methane bubbles from these deeper sediments can add methane to the hydrate stability zone. From these models it appears that recycling and upward migration of methane is essential in forming significant gas hydrate concentrations. In addition, the depth distribution profiles of methane hydrate will differ if the majority of the methane has migrated upward rather than having been produced in situ.

  3. Estimates of Biogenic Methane Production Rates in Deep Marine Sediments

    NASA Astrophysics Data System (ADS)

    Colwell, F. S.; Boyd, S.; Delwiche, M. E.; Reed, D. W.

    2004-12-01

    Much of the methane in natural gas hydrates in marine sediments is made by methanogens. Current models used to predict hydrate distribution and concentration in these sediments require estimates of microbial methane production rates. However, accurate estimates are difficult to achieve because of the bias introduced by sampling and because methanogen activities in these sediments are low and not easily detected. To derive useful methane production rates for marine sediments we have measured the methanogen biomass in samples taken from different depths in Hydrate Ridge (HR) sediments off the coast of Oregon and, separately, the minimal rates of activity for a methanogen in a laboratory reactor. For methanogen biomass, we used a polymerase chain reaction assay in real time to target the methanogen-specific mcr gene. Using this method we found that a majority of the samples collected from boreholes at HR show no evidence of methanogens (detection limit: less than 100 methanogens per g of sediment). Most of the samples with detectable numbers of methanogens were from shallow sediments (less than 10 meters below seafloor [mbsf]) although a few samples with apparently high numbers of methanogens (greater than 10,000 methanogens per g) were from as deep as 230 mbsf and were associated with notable geological features (e.g., the bottom-simulating reflector and an ash-bearing zone with high fluid movement). Laboratory studies with Methanoculleus submarinus (isolated from a hydrate zone at the Nankai Trough) maintained in a biomass recycle reactor showed that when this methanogen is merely surviving, as is likely the case in deep marine sediments, it produces approximately 0.06 fmol methane per cell per day. This is far lower than rates reported for methanogens in other environments. By combining this estimate of specific methanogenic rates and an extrapolation from the numbers of methanogens at selected depths in the sediment column at HR sites we have derived a maximum

  4. Physiology and Genetics of Biogenic Methane-Production from Acetate

    SciTech Connect

    Sowers, Kevin R

    2013-04-04

    Biomass conversion catalyzed by methanogenic consortia is a widely available, renewable resource for both energy production and waste treatment. The efficiency of this process is directly dependent upon the interaction of three metabolically distinct groups of microorganisms; the fermentative and acetogenic Bacteria and the methanogenic Archaea. One of the rate limiting steps in the degradation of soluble organic matter is the dismutation of acetate, a predominant intermediate in the process, which accounts for 70 % or more of the methane produced by the methanogens. Acetate utilization is controlled by regulation of expression of carbon monoxide dehydrogensase (COdh), which catalyzes the dismutation of acetate. However, physiological and molecular factors that control differential substrate utilization have not been identified in these Archaea. Our laboratory has identified sequence elements near the promoter of the gene (cdh) encoding for COdh and we have confirmed that these sequences have a role in the in vivo expression of cdh. The current proposal focuses on identifying the regulatory components that interact with DNA and RNA elements, and identifying the mechanisms used to control cdh expression. We will determine whether expression is controlled at the level of transcription or if it is mediated by coordinate interaction of transcription initiation with other processes such as transcription elongation rate and differential mRNA stability. Utilizing recently sequenced methanosarcinal genomes and a DNA microarray currently under development genes that encode regulatory proteins and transcription factors will be identified and function confirmed by gene disruption and subsequent screening on different substrates. Functional interactions will be determined in vivo by assaying the effects of gene dosage and site-directed mutagenesis of the regulatory gene on the expression of a cdh::lacZ operon fusion. Results of this study will reveal whether this critical

  5. Microbially-Enhanced Coal Bed Methane: Strategies for Increased Biogenic Production

    NASA Astrophysics Data System (ADS)

    Davis, K.; Barhart, E. P.; Schweitzer, H. D.; Cunningham, A. B.; Gerlach, R.; Hiebert, R.; Fields, M. W.

    2014-12-01

    Coal is the largest fossil fuel resource in the United States. Most of this coal is deep in the subsurface making it costly and potentially dangerous to extract. However, in many of these deep coal seams, methane, the main component of natural gas, has been discovered and successfully harvested. Coal bed methane (CBM) currently accounts for approximately 7.5% of the natural gas produced in the U.S. Combustion of natural gas produces substantially less CO2 and toxic emissions (e.g. heavy metals) than combustion of coal or oil thereby making it a cleaner energy source. In the large coal seams of the Powder River Basin (PRB) in southeast Montana and northeast Wyoming, CBM is produced almost entirely by biogenic processes. The in situ conversion of coal to CBM by the native microbial community is of particular interest for present and future natural gas sources as it provides the potential to harvest energy from coal seams with lesser environmental impacts than mining and burning coal. Research at Montana State University has shown the potential for enhancing the subsurface microbial processes that produce CBM. Long-term batch enrichments have investigated the methane enhancement potential of yeast extract as well as algal and cyanobacterial biomass additions with increased methane production observed with all three additions when compared to no addition. Future work includes quantification of CBM enhancement and normalization of additions. This presentation addresses the options thus far investigated for increasing CBM production and the next steps for developing the enhanced in situ conversion of coal to CBM.

  6. Biogenic Methane from Coal: The Oxidation Factor

    NASA Astrophysics Data System (ADS)

    Gallagher, L. K.; Glossner, A. W.; Landkamer, L.; Figueroa, L. A.; Mandernack, K. W.; Munakata Marr, J.

    2011-12-01

    Vast reserves of coal represent an untapped resource that can be used to produce methane gas, a cleaner energy alternative compared to standard fossil fuels. Microorganisms have demonstrated the ability to utilize coal as a carbon source, producing biogenic methane. With increasing demand for cleaner energy resources, understanding and enhancing biogenic methane production has become an area of active research. The conversion of coal to methane by microorganisms has been demonstrated experimentally by a number of research groups, but the state of the coal used as a substrate has not always been reported and may impact biogenic methane production. Microcosm experiments were designed in order to assess how the oxidation state of coal might influence methane production (e.g. as in a dewatered coal-bed natural gas system). Oxidized and un-oxidized coal samples from the Powder River Basin were incubated in microcosms inoculated with an enrichment culture that was derived from coal. Microcosms were characterized by headspace gas analysis, organic acid production, functional gene abundance (qPCR), and pyrosequencing of the 16S rRNA gene. Although the microbial consortium demonstrated the ability to utilize both oxidized and un-oxidized coal as a sole carbon source to generate methane, it was produced in higher quantities from the un-oxidized coal. This microbial community was dominated by Methanobacteriaceae (45%), epsilon-Proteobacteria (32%) and delta-Proteobacteria (13%). The results of this study provide a basis to develop strategies to enhance biogenic methane production from coal, as well as demonstrate the need for careful substrate preparation for inter-study comparisons.

  7. Redefining the isotopic boundaries of biogenic methane: Methane from endoevaporites

    NASA Astrophysics Data System (ADS)

    Tazaz, Amanda M.; Bebout, Brad M.; Kelley, Cheryl A.; Poole, Jennifer; Chanton, Jeffrey P.

    2013-06-01

    The recent reports of methane in the atmosphere of Mars, as well as the findings of hypersaline paleoenvironments on that planet, have underscored the need to evaluate the importance of biological (as opposed to geological) trace gas production and consumption, particularly in hypersaline environments. Methane in the atmosphere of Mars may be an indication of extant life, but it may also be a consequence of geologic activity and/or the thermal alteration of ancient organic matter. On Earth these methane sources can be distinguished using stable isotopic analyses and the ratio of methane (C1) to C2 and C3 alkanes present in the gas source (C1/(C2 + C3)). We report here that methane produced in hypersaline environments on Earth has an isotopic composition and alkane content outside the values presently considered to indicate a biogenic origin. Methane-rich bubbles released from sub-aqueous substrates contained δ13CCH4 and δ2HCH4 values ranging from -65‰ to -35‰ and -350‰ to -140‰ respectively. Higher salinity endoevaporites yielded what would be considered non-biogenic methane based upon stable isotopic and alkane content, however incubation of crustal and algal mat samples resulted in methane production with similar isotopic values. Radiocarbon analysis indicated that the production of the methane was from recently fixed carbon. An extension of the isotopic boundaries of biogenic methane is necessary in order to avoid the possibility of false negatives returned from measurements of methane on Mars and other planetary bodies.

  8. Estimates of Biogenic Methane Production Rates in Deep Marine Sediments at Hydrate Ridge, Cascadia Margin

    SciTech Connect

    F. S. Colwell; S. Boyd; M. E. Delwiche; D. W. Reed; T. J. Phelps; D. T. Newby

    2008-06-01

    Methane hydrate found in marine sediments is thought to contain gigaton quantities of methane and is considered an important potential fuel source and climate-forcing agent. Much of the methane in hydrates is biogenic, so models that predict the presence and distribution of hydrates require accurate rates of in situ methanogenesis. We estimated the in situ methanogenesis rates in Hydrate Ridge (HR) sediments by coupling experimentally derived minimal rates of methanogenesis to methanogen biomass determinations for discrete locations in the sediment column. When starved in a biomass recycle reactor Methanoculleus submarinus produced ca. 0.017 fmol methane/cell/day. Quantitative polymerase chain reaction (QPCR) directed at the methyl coenzyme M reductase subunit A (mcrA) gene indicated that 75% of the HR sediments analyzed contained <1000 methanogens/g. The highest methanogen numbers were mostly from sediments <10 meters below seafloor. By combining methanogenesis rates for starved methanogens (adjusted to account for in situ temperatures) and the numbers of methanogens at selected depths we derived an upper estimate of <4.25 fmol methane produced/g sediment/day for the samples with fewer methanogens than the QPCR method could detect. The actual rates could vary depending on the real number of methanogens and various seafloor parameters that influence microbial activity. However, our calculated rate is lower than rates previously reported from such sediments and close to the rate derived using geochemical modeling of the sediments. These data will help to improve models that predict microbial gas generation in marine sediments and determine the potential influence of this source of methane on the global carbon cycle.

  9. Estimates of biogenic methane production rates in deep marine sediments at Hydrate Ridge, Cascadia margin.

    PubMed

    Colwell, F S; Boyd, S; Delwiche, M E; Reed, D W; Phelps, T J; Newby, D T

    2008-06-01

    Methane hydrate found in marine sediments is thought to contain gigaton quantities of methane and is considered an important potential fuel source and climate-forcing agent. Much of the methane in hydrates is biogenic, so models that predict the presence and distribution of hydrates require accurate rates of in situ methanogenesis. We estimated the in situ methanogenesis rates in Hydrate Ridge (HR) sediments by coupling experimentally derived minimal rates of methanogenesis to methanogen biomass determinations for discrete locations in the sediment column. When starved in a biomass recycle reactor, Methanoculleus submarinus produced ca. 0.017 fmol methane/cell/day. Quantitative PCR (QPCR) directed at the methyl coenzyme M reductase subunit A gene (mcrA) indicated that 75% of the HR sediments analyzed contained <1,000 methanogens/g. The highest numbers of methanogens were found mostly from sediments <10 m below seafloor. By considering methanogenesis rates for starved methanogens (adjusted to account for in situ temperatures) and the numbers of methanogens at selected depths, we derived an upper estimate of <4.25 fmol methane produced/g sediment/day for the samples with fewer methanogens than the QPCR method could detect. The actual rates could vary depending on the real number of methanogens and various seafloor parameters that influence microbial activity. However, our calculated rate is lower than rates previously reported for such sediments and close to the rate derived using geochemical modeling of the sediments. These data will help to improve models that predict microbial gas generation in marine sediments and determine the potential influence of this source of methane on the global carbon cycle.

  10. Formation temperatures of thermogenic and biogenic methane

    USGS Publications Warehouse

    Stolper, D.A.; Lawson, M.; Davis, C.L.; Ferreira, A.A.; Santos Neto, E. V.; Ellis, G.S.; Lewan, M.D.; Martini, A.M.; Tang, Y.; Schoell, M.; Sessions, A.L.; Eiler, J.M.

    2014-01-01

    Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a “clumped isotope” technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.

  11. The Clumped Isotope Composition of Biogenic Methane.

    NASA Astrophysics Data System (ADS)

    Sessions, A. L.; Douglas, P. M.; Eiler, J. M.; Stolper, D. A.

    2015-12-01

    The excess or lack of 13CH3D, a doubly substituted ("clumped") isotopologue of methane, relative to that expected for a random distribution of isotopes across molecules, is a function of the processes that generated the methane. For high-temperature thermogenic methane, which typically achieves internal equilibrium, an excess of 13CH3D is expected and the amount of excess can serve as a thermometer. In contrast, biogenic methane often - though not always - has a smaller excess of clumped isotopologues, and sometimes even a deficit of clumped species ("anti-clumped"). The effect presumably arises from kinetic isotope effects accompanying enzymatic reactions in the methanogenic pathway, though the particular reaction(s) has not yet been positively identified. The decrease in clumping is also known to correlate with both the reversibility of the pathway and the methane flux. In this talk, we will present recent data bearing on the origin and utility of biologic fractionations of clumped isotopologues in methane. Preliminary data suggest that methane deriving from the fermentative pathway is enriched in D-bearing isotopologues, at the same level of clumping, relative to that derived from the CO2-reductive pathway. This property offers another potential means to distinguish biogenic methane sources in the environment. Recently, we have also begun to measure the 12CH2D2 isotopologue, for which equilibrium and kinetic isotope effects are predicted to be distinct from 13CH3D. Preliminary data suggest that the combination of both doubly-substituted isotopologues will be especially useful for disentangling mixtures containing biogenic gas.

  12. Biogenic hydrogen and methane production from Chlorella vulgaris and Dunaliella tertiolecta biomass

    PubMed Central

    2011-01-01

    Background Microalgae are a promising feedstock for biofuel and bioenergy production due to their high photosynthetic efficiencies, high growth rates and no need for external organic carbon supply. In this study, utilization of Chlorella vulgaris (a fresh water microalga) and Dunaliella tertiolecta (a marine microalga) biomass was tested as a feedstock for anaerobic H2 and CH4 production. Results Anaerobic serum bottle assays were conducted at 37°C with enrichment cultures derived from municipal anaerobic digester sludge. Low levels of H2 were produced by anaerobic enrichment cultures, but H2 was subsequently consumed even in the presence of 2-bromoethanesulfonic acid, an inhibitor of methanogens. Without inoculation, algal biomass still produced H2 due to the activities of satellite bacteria associated with algal cultures. CH4 was produced from both types of biomass with anaerobic enrichments. Polymerase chain reaction-denaturing gradient gel electrophoresis profiling indicated the presence of H2-producing and H2-consuming bacteria in the anaerobic enrichment cultures and the presence of H2-producing bacteria among the satellite bacteria in both sources of algal biomass. Conclusions H2 production by the satellite bacteria was comparable from D. tertiolecta (12.6 ml H2/g volatile solids (VS)) and from C. vulgaris (10.8 ml H2/g VS), whereas CH4 production was significantly higher from C. vulgaris (286 ml/g VS) than from D. tertiolecta (24 ml/g VS). The high salinity of the D. tertiolecta slurry, prohibitive to methanogens, was the probable reason for lower CH4 production. PMID:21943287

  13. Effects of composition of labile organic matter on biogenic production of methane in the coastal sediments of the Arabian Sea.

    PubMed

    Gonsalves, Maria-Judith; Fernandes, Christabelle E G; Fernandes, Sheryl Oliveira; Kirchman, David L; Bharathi, P A Loka

    2011-11-01

    Coastal regions are potential zones for production of methane which could be governed by ecological/environmental differences or even sediment properties of a niche. In order to test the hypothesis that methanogenesis in most marine sediments could be driven more by proteins than by carbohydrates and lipid content of labile organic matter (LOM), incubation experiments were carried out with sediments from different environmental niches to measure methane production. The methane production rates were examined in relationship to the sediment biochemistry, i.e., carbohydrates, proteins, and lipids. The gas production measured by head space method ranged from 216 ng g( -1) day( -1) in the mangrove sediments to 3.1 μg g( -1) day( -1) in the shallow Arabian Sea. LOM ranged from 1.56 to 2.85 mg g( -1) in the shallow Arabian Sea, from 3.35 to 5.43 mg g( -1) in the mangrove estuary, and from 0.66 to 0.70 mg g( -1) in the sandy sediments with proteins contributing maximum to the LOM pool. Proteins influenced methane production in the clayey sediments of shallow depths of the Arabian Sea (r = 0.933, p < 0.001) and mangrove estuary (r = 0.981, p < 0.001) but in the sandy beach sediments, carbohydrates (r = 0.924, p < 0.001) governed the net methane production. The gas production was more pronounced in shallow and surface sediments and it decreased with depth apparently governed by the decrease in lability index. Thus, the lability index and protein content are important factors that determine methane production rates in these coastal ecosystems.

  14. Approaching Mars-like Geochemical Conditions in the Laboratory: Omission of Artificial Buffers and Reductants in a Study of Biogenic Methane Production on a Smectite Clay

    NASA Astrophysics Data System (ADS)

    Chastain, Brendon K.; Kral, Timothy A.

    2010-11-01

    Methanogens have not been shown to metabolize in conditions exactly analogous to those present in Mars' subsurface. In typical studies of methanogenic metabolism, nutrient-rich buffered media and reducing agents are added to the cultures in an attempt to optimize the environment for methanogen survival and growth. To study methanogens in more Mars-relevant laboratory conditions, efforts should be made to eliminate artificial media, buffers, and reducing agents from investigations of methanogenic metabolism. After preliminary work to compare methanogen viability on montmorillonite clay and JSC Mars-1 regolith simulant, a study was conducted to determine whether biological methanogenesis could occur in non-reduced, non-buffered environments containing only H2, CO2, montmorillonite, and the liquid fraction extracted from a montmorillonite/deionized water suspension. Biogenic methane was observed in the microenvironments despite the omission of traditional media, buffers, and reducing agents. Mean headspace methane concentration after 96 days of observation was 10.23 ± 0.64% (% vol ± SEM, n = 4). However, methane production was severely decreased with respect to reduced, buffered microenvironments (Day 28: 31.98% ± 0.19%, n = 3). Analysis of results and comparison to previous work indicate that montmorillonite clay has a strong ability to supply micronutrients necessary for methanogenic metabolism, and the liquid fraction from a montmorillonite/deionized water slurry can successfully be used as an alternative to reduced and buffered nutritive media in Mars-relevant studies of methanogenic metabolism.

  15. Biogenic Methane and the Rise of Oxygen

    NASA Technical Reports Server (NTRS)

    Catling, David; McKay, Christopher

    2001-01-01

    Oxygenic photosynthesis does not make the rise of oxygen inevitable. What is required is that reductant and oxygen be separated and permanently segregated. The usual picture for Earth is that oxygenic photosynthesis split CO2 into carbon and oxygen, with the carbon buried in sediments and the oxygen mostly taken up by oxides of iron and sulfur. The relatively small atmospheric reservoir of O2 is regulated by the carbon burial rate, reaction with volcanic and metamorphic gases, and oxidation of reduced carbon released as old sediments weather. Absent from this picture is a distinction between the Archean and modern times: on average, carbon burial fluxes would have been matched by oxygen losses then as now. Separation of reductant from oxidant is only provisional. No net oxidation of the continents occurs, and so no change of diagenetic, metamorphic, or volcanic gases is expected. Nor would any change in oxidative weathering be expected. Something more than carbon burial is required to make the Archean different. The escape of hydrogen to space permanently separates the reductant from the oxidant. Hydrogen escape is widely believed to have led to the present highly oxidized states of Mars and Venus. Hydrogen escape has usually been thought small for Archaean Earth, because water vapor is cold-trapped at the troposphere and thus held to levels of a few ppmv in the stratosphere. This cold trapping renders hydrogen escape negligible. However, methane is not cold trapped, and its expected abundance in the Archaean, given low oxygen levels and a biogenic source, would have been high, probably more than 100 times present. At such levels methane would have driven geologically significant levels of hydrogen escape. Additional information is contained in the original extended abstract.

  16. Insights into Methane Formation Temperatures, Biogenic Methanogenesis, and Natural Methane Emissions from Clumped Isotopes

    NASA Astrophysics Data System (ADS)

    Douglas, P. M.; Stolper, D. A.; Walter Anthony, K. M.; Dallimore, S.; Paull, C. K.; Wik, M.; Crill, P. M.; Winterdahl, M.; Smith, D. A.; Luhmann, A. J.; Ding, K.; Seyfried, W. E., Jr.; Eiler, J. M.; Ponton, C.; Sessions, A. L.

    2015-12-01

    Multiply substituted isotopologues of methane are a valuable new tool for characterizing and understanding the source of methane in different Earth environments. Here we present methane clumped isotope results from natural gas wells, hydrothermal vents, marine and lacustrine methane seeps, and culture experiments. We observe a wide range of formation temperatures for thermogenic methane. Methane samples from low-maturity reservoirs indicate formation temperatures between 102-144° C, high-maturity conventional and shale gasses indicate temperatures between 158-246 °C, and thermogenic coal gases indicate temperatures between 174-267 °C. Methane formation temperatures generally correlate positively with δ13C, and negatively with gas wetness indices. Methane samples from a set of marine hydrothermal vents indicate a formation temperature of 290-350 °C. Methane sampled from subsurface and marine biogenic sources typically indicate temperatures consistent with the formation environment (0-64° C). In contrast, freshwater biogenic methane samples, and cultures of hydrogenotrophic and methylotrophic methanogens, express low levels of isotopic clumping inconsistent with their formation temperature. These data and complementary models suggest that kinetic isotope effects, likely modulated by rates and pathways of methanogenesis, affect biogenic methane in cultures and freshwater environments. Alternatively, non-equilibrium signatures may result from mixing of methane with widely differing δD and δ13C values. Analyses of biogenic methane emissions from lakes indicate a correlation between methane flux and non-equilibrium clumped isotope fractionations in a given lake. Results from large methane seeps in Alaskan lakes confirm that some seeps emit thermogenic methane, but also indicate that other seeps emit subsurface biogenic methane or variable mixtures of biogenic and thermogenic methane. These results point to diverse sources for large Arctic methane seeps.

  17. Approaching Mars-like geochemical conditions in the laboratory: omission of artificial buffers and reductants in a study of biogenic methane production on a smectite clay.

    PubMed

    Chastain, Brendon K; Kral, Timothy A

    2010-11-01

    Methanogens have not been shown to metabolize in conditions exactly analogous to those present in Mars' subsurface. In typical studies of methanogenic metabolism, nutrient-rich buffered media and reducing agents are added to the cultures in an attempt to optimize the environment for methanogen survival and growth. To study methanogens in more Mars-relevant laboratory conditions, efforts should be made to eliminate artificial media, buffers, and reducing agents from investigations of methanogenic metabolism. After preliminary work to compare methanogen viability on montmorillonite clay and JSC Mars-1 regolith simulant, a study was conducted to determine whether biological methanogenesis could occur in non-reduced, non-buffered environments containing only H(2), CO(2), montmorillonite, and the liquid fraction extracted from a montmorillonite/deionized water suspension. Biogenic methane was observed in the microenvironments despite the omission of traditional media, buffers, and reducing agents. Mean headspace methane concentration after 96 days of observation was 10.23% ± 0.64% (% vol ± SEM, n = 4). However, methane production was severely decreased with respect to reduced, buffered microenvironments (Day 28: 31.98% ± 0.19%, n = 3). Analysis of results and comparison to previous work indicate that montmorillonite clay has a strong ability to supply micronutrients necessary for methanogenic metabolism, and the liquid fraction from a montmorillonite/deionized water slurry can successfully be used as an alternative to reduced and buffered nutritive media in Mars-relevant studies of methanogenic metabolism.

  18. Gas formation. Formation temperatures of thermogenic and biogenic methane.

    PubMed

    Stolper, D A; Lawson, M; Davis, C L; Ferreira, A A; Santos Neto, E V; Ellis, G S; Lewan, M D; Martini, A M; Tang, Y; Schoell, M; Sessions, A L; Eiler, J M

    2014-06-27

    Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a "clumped isotope" technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.

  19. Rn-222 tracing and stable isotope measurements of biogenic gas fluxes from methane saturated sediments

    NASA Technical Reports Server (NTRS)

    Martens, Christopher S.; Green, C. D.; Blair, Neal; Chanton, J. P.

    1985-01-01

    Transport of reduced biogenic gases from anoxic sediments and soils to the atmosphere can be quantitatively studied through measurement of radon-222/radium-226 disequilibrium. In previous work, seasonal variations in biogenic gas transport mechanisms, net fluxes and overall composition were documented. Now presented are direct field measurements of radon-222 activity in gases exiting organic rich sediments which show their usefulness for tracing of the stripping of dissolved biogenic gases from within the sediment column and transport via bubble ebullition. Methane is depleted in deuterium during the summer as compared with winter months and is in general lighter than in most marine sediments signaling the probable importance of acetate as an important precursor molecule. The significant seasonal isotopic variations observed illustrate the importance of understanding mechanisms and rates of biogenic gas production in order to interpret observed tropospheric isotopic data.

  20. Methane production in terrestrial arthropods.

    PubMed Central

    Hackstein, J H; Stumm, C K

    1994-01-01

    We have screened more than 110 representatives of the different taxa of terrestrial arthropods for methane production in order to obtain additional information about the origins of biogenic methane. Methanogenic bacteria occur in the hindguts of nearly all tropical representatives of millipedes (Diplopoda), cockroaches (Blattaria), termites (Isoptera), and scarab beetles (Scarabaeidae), while such methanogens are absent from 66 other arthropod species investigated. Three types of symbiosis were found: in the first type, the arthropod's hindgut is colonized by free methanogenic bacteria; in the second type, methanogens are closely associated with chitinous structures formed by the host's hindgut; the third type is mediated by intestinal anaerobic protists with intracellular methanogens. Such symbiotic associations are likely to be a characteristic property of the particular taxon. Since these taxa represent many families with thousands of species, the world populations of methane-producing arthropods constitute an enormous biomass. We show that arthropod symbionts can contribute substantially to atmospheric methane. Images PMID:8202505

  1. Methane production in terrestrial arthropods

    SciTech Connect

    Hackstein, J.H.P.; Stumm, C.K. )

    1994-06-07

    The authors have screened more than 110 representatives of the different taxa of terrestrial arthropods for methane production in order to obtain additional information about the origins of biogenic methane. Methanogenic bacteria occur in the hindguts of nearly all tropical representatives of millipedes (Diplopoda), cockroaches (Blattaria), termites (Isoptera), and scarab beetles (Scarabaeidae), while such methanogens are absent from 66 other arthropod species investigated. Three types of symbiosis were found: in the first type, the arthropod's hindgut is colonized by free methanogenic bacteria; in the second type, methanogens are closely associated with chitinous structures formed by the host's hindgut; the third type is mediated by intestinal anaerobic protists with intracellular methanogens. Such symbiotic associations are likely to be a characteristic property of the particular taxon. Since these taxa represent many families with thousands of species, the world populations of methane-producing arthropods constitute an enormous biomass. The authors show that arthropod symbionts can contribute substantially to atmospheric methane.

  2. Seasonal variations in the stable carbon isotopic signature of biogenic methane in a coastal sediment

    NASA Technical Reports Server (NTRS)

    Martens, C. S.; Green, C. D.; Blair, N. E.; Des Marais, D. J.

    1986-01-01

    Systematic seasonal variations in the stable carbon isotopic signature of methane gas occur in the anoxic sediments of Cape Lookout Bight, a lagoonal basin on North Carolina's Outer Banks. Values for the carbon isotope ratio of methane range from -57.3 per mil during summer to -68.5 per mil during winter in gas bubbles with an average methane content of 95 percent. The variations are hypothesized to result from changes in the pathways of microbial methane production and cycling of key substrates including acetate and hydrogen. The use of stable isotopic signatures to investigate the global methane cycle through mass balance calculations, involving various sediment and soil biogenic sources, appears to require seasonally averaged data from individual sites.

  3. Seasonal variations in the stable carbon isotopic signature of biogenic methane in a coastal sediment

    SciTech Connect

    Martens, C.S.; Blair, N.E.; Green, C.D.; Des Marais, D.J.

    1986-09-19

    Systematic seasonal variations in the stable carbon isotopic signature of methane gas occur in the anoxic sediments of Cape Lookout Bight, a lagoonal basin on North Carolina's Outer Banks. Values for the carbon isotope ratio (delta /sup 13/C) of methane range from -57.3 per mil during summer to -68.5 per mil during winter in gas bubbles with an average methane content of 95%. The variations are hypothesized to result from changes in the pathways of microbial methane production and cycling of key substrates including acetate and hydrogen. The use of stable isotopic signatures to investigate the global methane cycle through mass balance calculations, involving various sediment and soil biogenic sources, appears to require seasonally averaged data from individual sites. 17 references, 2 figures, 2 tables.

  4. Bioassay for estimating the biogenic methane-generating potential of coal samples

    USGS Publications Warehouse

    Jones, E.J.P.; Voytek, M.A.; Warwick, P.D.; Corum, M.D.; Cohn, A.; Bunnell, J.E.; Clark, A.C.; Orem, W.H.

    2008-01-01

    Generation of secondary biogenic methane in coal beds is likely controlled by a combination of factors such as the bioavailability of coal carbon, the presence of a microbial community to convert coal carbon to methane, and an environment supporting microbial growth and methanogenesis. A set of treatments and controls was developed to bioassay the bioavailability of coal for conversion to methane under defined laboratory conditions. Treatments included adding a well-characterized consortium of bacteria and methanogens (enriched from modern wetland sediments) and providing conditions to support endemic microbial activity. The contribution of desorbed methane in the bioassays was determined in treatments with bromoethane sulfonic acid, an inhibitor of microbial methanogenesis. The bioassay compared 16 subbituminous coal samples collected from beds in Texas (TX), Wyoming (WY), and Alaska (AK), and two bituminous coal samples from Pennsylvania (PA). New biogenic methane was observed in several samples of subbituminous coal with the microbial consortium added, but endemic activity was less commonly observed. The highest methane generation [80????mol methane/g coal (56??scf/ton or 1.75??cm3/g)] was from a south TX coal sample that was collected from a non-gas-producing well. Subbituminous coals from the Powder River Basin, WY and North Slope Borough, AK contained more sorbed (original) methane than the TX coal sample and generated 0-23????mol/g (up to 16??scf/ton or 0.5??cm3/g) new biogenic methane in the bioassay. Standard indicators of thermal maturity such as burial depth, nitrogen content, and calorific value did not explain differences in biogenic methane among subbituminous coal samples. No original methane was observed in two bituminous samples from PA, nor was any new methane generated in bioassays of these samples. The bioassay offers a new tool for assessing the potential of coal for biogenic methane generation, and provides a platform for studying the

  5. The effects of fire on biogenic emissions of methane and nitric oxide from wetlands

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.; Cofer, Wesley R., III; Sebacher, Daniel I.; Rhinehart, Robert P.; Winstead, Edward L.; Sebacher, Shirley; Hinkle, C. Ross; Schmalzer, Paul A.; Koller, Albert M., Jr.

    1990-01-01

    Enhanced emissions of methane (CH4) and nitric oxide (NO) were measured following three controlled burns in a Florida wetlands in 1987 and 1988. Wetlands are the major global source of methane resulting from metabolic activity of methanogenic bacteria. Methanogens require carbon dioxide, acetate, or formate for their growth and the metabolic production of methane. All three water-soluble compounds are produced in large concentrations during biomass burning. Postfire methane emissions exceeded 0.15 g CH 4/sq m per day. Preburn and postburn measurements of soil nutrients indicate significant postburn increases in soil ammonium, from 8.35 to 13.49 parts per million (ppm) in the upper 5 cm of the Juncus marsh and from 8.83 to 23.75 ppm in the upper 5 cm of the Spartina marsh. Soil nitrate concentrations were found to decrease in both marshes after the fire. These measurements indicate that the combustion products of biomass burning exert an important 'fertilizing' effect on the biosphere and on the biogenic production of environmentally significant atmospheric gases.

  6. Deposition of biogenic iron minerals in a methane oxidizing microbial mat.

    PubMed

    Wrede, Christoph; Kokoschka, Sebastian; Dreier, Anne; Heller, Christina; Reitner, Joachim; Hoppert, Michael

    2013-01-01

    The syntrophic community between anaerobic methanotrophic archaea and sulfate reducing bacteria forms thick, black layers within multi-layered microbial mats in chimney-like carbonate concretions of methane seeps located in the Black Sea Crimean shelf. The microbial consortium conducts anaerobic oxidation of methane, which leads to the formation of mainly two biomineral by-products, calcium carbonates and iron sulfides, building up these chimneys. Iron sulfides are generated by the microbial reduction of oxidized sulfur compounds in the microbial mats. Here we show that sulfate reducing bacteria deposit biogenic iron sulfides extra- and intracellularly, the latter in magnetosome-like chains. These chains appear to be stable after cell lysis and tend to attach to cell debris within the microbial mat. The particles may be important nuclei for larger iron sulfide mineral aggregates.

  7. Enhanced Microbial Pathways for Methane Production from Oil Shale

    SciTech Connect

    Paul Fallgren

    2009-02-15

    Methane from oil shale can potentially provide a significant contribution to natural gas industry, and it may be possible to increase and continue methane production by artificially enhancing methanogenic activity through the addition of various substrate and nutrient treatments. Western Research Institute in conjunction with Pick & Shovel Inc. and the U.S. Department of Energy conducted microcosm and scaled-up reactor studies to investigate the feasibility and optimization of biogenic methane production from oil shale. The microcosm study involving crushed oil shale showed the highest yield of methane was produced from oil shale pretreated with a basic solution and treated with nutrients. Incubation at 30 C, which is the estimated temperature in the subsurface where the oil shale originated, caused and increase in methane production. The methane production eventually decreased when pH of the system was above 9.00. In the scaled-up reactor study, pretreatment of the oil shale with a basic solution, nutrient enhancements, incubation at 30 C, and maintaining pH at circumneutral levels yielded the highest rate of biogenic methane production. From this study, the annual biogenic methane production rate was determined to be as high as 6042 cu. ft/ton oil shale.

  8. Methylotrophic methanogenesis governs the biogenic coal bed methane formation in Eastern Ordos Basin, China.

    PubMed

    Guo, Hongguang; Yu, Zhisheng; Liu, Ruyin; Zhang, Hongxun; Zhong, Qiding; Xiong, Zhenghe

    2012-12-01

    To identify themethanogenic pathways present in a deep coal bed methane (CBM) reservoir associated with Eastern Ordos Basin in China, a series of geochemical and microbiological studies was performed using gas and water samples produced from the Liulin CBM reservoir. The composition and stable isotopic ratios of CBM implied a mixed biogenic and thermogenic origin of the methane. Archaeal 16S rRNA gene analysis revealed the dominance of the methylotrophic methanogen Methanolobus in the water produced. The high potential of methane production by methylotrophic methanogens was found in the enrichments using the water samples amended with methanol and incubated at 25 and 35 °C. Methylotrophic methanogens were the dominant archaea in both enrichments as shown by polymerase chain reaction (PCR)–denaturing gradient gel electrophoresis (DGGE). Bacterial 16S rRNA gene analysis revealed that fermentative, sulfate-reducing, and nitrate-reducing bacteria inhabiting the water produced were a factor in coal biodegradation to fuel methanogens. These results suggested that past and ongoing biodegradation of coal by methylotrophic methanogens and syntrophic bacteria, as well as thermogenic CBM production, contributed to the Liulin CBM reserves associated with the Eastern Ordos Basin.

  9. Biochemically enhanced methane production from coal

    NASA Astrophysics Data System (ADS)

    Opara, Aleksandra

    For many years, biogas was connected mostly with the organic matter decomposition in shallow sediments (e.g., wetlands, landfill gas, etc.). Recently, it has been realized that biogenic methane production is ongoing in many hydrocarbon reservoirs. This research examined microbial methane and carbon dioxide generation from coal. As original contributions methane production from various coal materials was examined in classical and electro-biochemical bench-scale reactors using unique, developed facultative microbial consortia that generate methane under anaerobic conditions. Facultative methanogenic populations are important as all known methanogens are strict anaerobes and their application outside laboratory would be problematic. Additional testing examined the influence of environmental conditions, such as pH, salinity, and nutrient amendments on methane and carbon dioxide generation. In 44-day ex-situ bench-scale batch bioreactor tests, up to 300,000 and 250,000 ppm methane was generated from bituminous coal and bituminous coal waste respectively, a significant improvement over 20-40 ppm methane generated from control samples. Chemical degradation of complex hydrocarbons using environmentally benign reagents, prior to microbial biodegradation and methanogenesis, resulted in dissolution of up to 5% bituminous coal and bituminous coal waste and up to 25% lignite in samples tested. Research results confirm that coal waste may be a significant underutilized resource that could be converted to useful fuel. Rapid acidification of lignite samples resulted in low pH (below 4.0), regardless of chemical pretreatment applied, and did not generate significant methane amounts. These results confirmed the importance of monitoring and adjusting in situ and ex situ environmental conditions during methane production. A patented Electro-Biochemical Reactor technology was used to supply electrons and electron acceptor environments, but appeared to influence methane generation in a

  10. Methane photochemistry and methane production on Neptune

    NASA Technical Reports Server (NTRS)

    Romani, P. N.; Atreya, S. K.

    1988-01-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus.

  11. Methane photochemistry and methane production on Neptune

    SciTech Connect

    Romani, P.N.; Atreya, S.K.

    1988-06-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus. 65 references.

  12. Methane photochemistry and methane production on Neptune

    NASA Astrophysics Data System (ADS)

    Romani, P. N.; Atreya, S. K.

    1988-06-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus.

  13. Effect of Nitrate on Biogenic Sulfide Production

    PubMed Central

    Jenneman, Gary E.; McInerney, M. J.; Knapp, Roy M.

    1986-01-01

    The addition of 59 mM nitrate inhibited biogenic sulfide production in dilute sewage sludge (10% [vol/vol]) amended with 20 mM sulfate and either acetate, glucose, or hydrogen as electron donors. Similar results were found when pond sediment or oil field brines served as the inoculum. Sulfide production was inhibited for periods of at least 6 months and was accompanied by the oxidation of resazurin from its colorless reduced state to its pink oxidized state. Lower amounts of nitrate (6 or 20 mM) and increased amounts of sewage sludge resulted in only transient inhibition of sulfide production. The addition of 156 mM sulfate to bottles with 59 mM nitrate and 10% (vol/vol) sewage sludge or pond sediment resulted in sulfide production. Nitrate, nitrite, and nitrous oxide were detected during periods where sulfide production was inhibited, whereas nitrate, nitrite, and nitrous oxide were below detectable levels at the time sulfide production began. The oxidation of resazurin was attributed to an increase in nitrous oxide which persisted in concentration of about 1.0 mM for up to 5 months. The numbers of sulfate-reducing organisms decreased from 106 CFU ml−1 sludge to less than detectable levels after prolonged incubation of oxidized bottles. The addition of 10 mM glucose to oxidized bottles after 14.5 weeks of incubation resulted in rereduction of the resazurin and subsequent sulfide production. The prolonged inhibition of sulfide production was attributed to an increase in oxidation-reduction potential due to biogenic production of nitrous oxide, which appeared to have a cytotoxic effect on sulfate-reducing populations. PMID:16347078

  14. A contribution of hydrogenotrophic methanogenesis to the biogenic coal bed methane reserves of Southern Qinshui Basin, China.

    PubMed

    Guo, Hongguang; Yu, Zhisheng; Thompson, Ian P; Zhang, Hongxun

    2014-11-01

    The activity of methanogens and related bacteria which inhabit the coal beds is essential for stimulating new biogenic coal bed methane (CBM) production from the coal matrix. In this study, the microbial community structure and methanogenesis were investigated in Southern Qinshui Basin in China, and the composition and stable isotopic ratios of CBM were also determined. Although geochemical analysis suggested a mainly thermogenic origin for CBM, the microbial community structure and activities strongly implied the presence of methanogens in situ. 454 pyrosequencing analysis combined with methyl coenzyme-M reductase (mcrA) gene clone library analysis revealed that the archaeal communities in the water samples from both coal seams were similar, with the dominance of hydrogenotrophic methanogen Methanobacterium. The activity and potential of these populations to produce methane were confirmed by the observation of methane production in enrichments supplemented with H2 + CO2 and formate, and the only archaea successfully propagated in the tested water samples was from the genus Methanobacterium. 454 pyrosequencing analysis also recovered the diverse bacterial communities in the water samples, which have the potential to play a role in the coal biodegradation fueling methanogens. These results suggest that the biogenic CBM was generated by coal degradation via the hydrogenotrophic methanogens and related bacteria, which also contribute to the huge CBM reserves in Southern Qinshui Basin, China.

  15. Controls on the stable carbon isotopic composition of biogenic methane produced in a tidal freshwater estaurine sediment

    SciTech Connect

    Avery, G.B. Jr.; Martens, C.S.

    1999-04-01

    The {delta}{sup 13}C value of methane in sediments from a tidal freshwater site in the White Oak River Estuary, North Carolina, exhibited a relatively small, but consistent, seasonal variation ({approximately}3{per_thousand}) with isotopically heavier values occurring during the warmer months ({minus}66.1{per_thousand} summer, {minus}69.2{per_thousand} winter). These isotopic shifts could have resulted from changes in: (1) isotopic compositions of precursor molecules; (2) kinetic isotope effects associated with methane production; or (3) pathways of methane production. Methane production rate and isotopic data from sediment incubation experiments and field measurements were used to determine the relative contributions of these factors to the observed seasonal variations. Although changes in {delta}{sup 13}C values of biogenic methane are typically thought to result from changes in pathways of methane production, this study showed that a significant amount (36 {+-} 22%) of the seasonal variations between the {delta}{sup 13}C value of methane produced in sediment incubation experiments could be attributed to changes in the {delta}{sup 13}C value of the {Sigma}CO{sub 2} pool. This was due to increased methane production rates and removal of {sup 12}CO{sub 2} with increasing temperature, a prevalent feature of methanogenic systems that may account for some of the frequently observed {sup 13}C enrichment in methane during warmer months. Combining the change in the {delta}{sup 13}C value of the {Sigma}CO{sub 2} pool with temperature-controlled changes in fractionation ({alpha}) resulting from kinetic isotope effects accounted for (53 {+-} 22%) of the {sup 13}C enrichment observed during summer sediment incubation experiments. Although large pathway changes were not observed in sediment incubation experiments, the remaining differences in {delta}{sup 13}C values could have resulted from smaller, undetectable changes in the percentage of methane production from acetate

  16. Extreme (13)C depletion of carbonates formed during oxidation of biogenic methane in fractured granite.

    PubMed

    Drake, Henrik; Åström, Mats E; Heim, Christine; Broman, Curt; Åström, Jan; Whitehouse, Martin; Ivarsson, Magnus; Siljeström, Sandra; Sjövall, Peter

    2015-05-07

    Precipitation of exceptionally 13C-depleted authigenic carbonate is a result of, and thus a tracer for, sulphate-dependent anaerobic methane oxidation, particularly in marine sediments. Although these carbonates typically are less depleted in 13C than in the source methane, because of incorporation of C also from other sources, they are far more depleted in 13C (δ13C as light as -69‰ V-PDB) than in carbonates formed where no methane is involved. Here we show that oxidation of biogenic methane in carbon-poor deep groundwater in fractured granitoid rocks has resulted in fracture-wall precipitation of the most extremely 13C-depleted carbonates ever reported, δ13C down to -125‰ V-PDB. A microbial consortium of sulphate reducers and methane oxidizers has been involved, as revealed by biomarker signatures in the carbonates and S-isotope compositions of co-genetic sulphide. Methane formed at shallow depths has been oxidized at several hundred metres depth at the transition to a deep-seated sulphate-rich saline water. This process is so far an unrecognized terrestrial sink of methane.

  17. Extreme 13C depletion of carbonates formed during oxidation of biogenic methane in fractured granite

    PubMed Central

    Drake, Henrik; Åström, Mats E.; Heim, Christine; Broman, Curt; Åström, Jan; Whitehouse, Martin; Ivarsson, Magnus; Siljeström, Sandra; Sjövall, Peter

    2015-01-01

    Precipitation of exceptionally 13C-depleted authigenic carbonate is a result of, and thus a tracer for, sulphate-dependent anaerobic methane oxidation, particularly in marine sediments. Although these carbonates typically are less depleted in 13C than in the source methane, because of incorporation of C also from other sources, they are far more depleted in 13C (δ13C as light as −69‰ V-PDB) than in carbonates formed where no methane is involved. Here we show that oxidation of biogenic methane in carbon-poor deep groundwater in fractured granitoid rocks has resulted in fracture-wall precipitation of the most extremely 13C-depleted carbonates ever reported, δ13C down to −125‰ V-PDB. A microbial consortium of sulphate reducers and methane oxidizers has been involved, as revealed by biomarker signatures in the carbonates and S-isotope compositions of co-genetic sulphide. Methane formed at shallow depths has been oxidized at several hundred metres depth at the transition to a deep-seated sulphate-rich saline water. This process is so far an unrecognized terrestrial sink of methane. PMID:25948095

  18. Extreme 13C depletion of carbonates formed during oxidation of biogenic methane in fractured granite

    NASA Astrophysics Data System (ADS)

    Drake, Henrik; Åström, Mats E.; Heim, Christine; Broman, Curt; Åström, Jan; Whitehouse, Martin; Ivarsson, Magnus; Siljeström, Sandra; Sjövall, Peter

    2015-05-01

    Precipitation of exceptionally 13C-depleted authigenic carbonate is a result of, and thus a tracer for, sulphate-dependent anaerobic methane oxidation, particularly in marine sediments. Although these carbonates typically are less depleted in 13C than in the source methane, because of incorporation of C also from other sources, they are far more depleted in 13C (δ13C as light as -69‰ V-PDB) than in carbonates formed where no methane is involved. Here we show that oxidation of biogenic methane in carbon-poor deep groundwater in fractured granitoid rocks has resulted in fracture-wall precipitation of the most extremely 13C-depleted carbonates ever reported, δ13C down to -125‰ V-PDB. A microbial consortium of sulphate reducers and methane oxidizers has been involved, as revealed by biomarker signatures in the carbonates and S-isotope compositions of co-genetic sulphide. Methane formed at shallow depths has been oxidized at several hundred metres depth at the transition to a deep-seated sulphate-rich saline water. This process is so far an unrecognized terrestrial sink of methane.

  19. Biogenic methane from abyssal brine seeps at the base of the Florida escarpment

    SciTech Connect

    Martens, C.S.; Chanton, J.P.; Paull, C.K. )

    1991-08-01

    Dissolved methane is present at concentrations exceeding 10mM in the pore waters of sulfidic, salt-brine-enriched sediments underlying chemosynthetic communities at the base of the Florida escarpment. Light hydrocarbon samples were obtained from brine seep sediments by means of an in situ probe and push cores deployed by the deep submersible Alvin. Pore-water methane had a {delta}{sup 13}C value of {minus}83.3 {plus minus}7.0 (Peedee belemnite, N = 17), contained < 1.3% modern carbon, and was enriched over ethane concentrations by 10{sup 3} to 10{sup 5}; these results all indicate a fossil, biogenic carbon source within the Florida platform. Methane-rich brine fluids arriving at seep sites are depleted in dissolved sulfate, although they have been diluted twenty-fold with sulfate-rich seawater during transit. It appears that sulfate reduction and methano-genesis are important processes within the platform.

  20. Investigations of Methane Production in Hypersaline Environments

    NASA Technical Reports Server (NTRS)

    Bebout, Brad M.

    2015-01-01

    The recent reports of methane in the atmosphere of Mars, as well as the findings of hypersaline paleo-environments on that planet, have underscored the need to evaluate the importance of biological (as opposed to geological) trace gas production and consumption. Methane in the atmosphere of Mars may be an indication of life but might also be a consequence of geologic activity and/or the thermal alteration of ancient organic matter. Hypersaline environments have now been reported to be extremely likely in several locations in our solar system, including: Mars, Europa, and Enceladus. Modern hypersaline microbial mat communities, (thought to be analogous to those present on the early Earth at a period of time when Mars was experiencing very similar environmental conditions), have been shown to produce methane. However, very little is known about the physical and/or biological controls imposed upon the rates at which methane, and other important trace gases, are produced and consumed in these environments. We describe here the results of our investigations of methane production in hypersaline environments, including field sites in Chile, Baja California Mexico, California, USA and the United Arab Emirates. We have measured high concentrations of methane in bubbles of gas produced both in the sediments underlying microbial mats, as well as in areas not colonized by microbial mats in the Guerrero Negro hypersaline ecosystem, Baja California Mexico, in Chile, and in salt ponds on the San Francisco Bay. The carbon isotopic (d13C) composition of the methane in the bubbles exhibited an extremely wide range of values, (ca. -75 per mille ca. -25 per mille). The hydrogen isotopic composition of the methane (d2H) ranged from -60 to -30per mille and -450 to -350per mille. These isotopic values are outside of the range of values normally considered to be biogenic, however incubations of the sediments in contact with these gas bubbles reveals that the methane is indeed being

  1. Methane production in Minnesota peatlands

    SciTech Connect

    Williams, R.T.; Crawford, R.L.

    1984-06-01

    Rates of methane production in Minnesota peats were studied. Surface (10- to 25-cm) peats produced an average of 228 nmol of CH/sub 4/ per g (dry weight) per h at 25/sup 0/C and ambient pH. Methanogenesis rates generally decreased with depth in ombrotrophic peats, but on occasion were observed to rise within deeper layers of certain fen peats. Methane production was temperature dependent, increasing with increasing temperature (4 to 30/sup 0/C), except in peats from deeper layers. Maximal methanogenesis from these deeper regions occurred at 12/sup 0/C. Methane production rates were also pH dependent. Two peats with pHs of 3.8 and 4.3 had an optimum rate of methane production at pH 6.0. The addition to peat of glucose and H/sub 2/-CO/sub 2/ stimulated methanogenesis, whereas the addition of acetate inhibited methanogenesis. Cysteine-sulfide, nitrogen-phosphorus-trace metals, and vitamins-yeast extract affected methane production very little. Various gases were found to be trapped or dissolved (or both) within peatland waters. Dissolved methane increased linearly to a depth of 210 cm. The accumulation of metabolic end products produced within peat bogs appears to be an important mechanism limiting turnover in peatland environments.

  2. Radon as a tracer of biogenic gas equilibration and transport from methane-saturated sediments

    NASA Technical Reports Server (NTRS)

    Martens, Christopher S.; Chanton, Jeffrey P.

    1989-01-01

    Data on Rn-222 activity in methane-rich gas bubbles from anoxic coastal sediments of Cape Lookout Bight, North Carolina, were used to determine gas equilibration with pore waters and the rates of ebullitive stripping and transport of gases to overlying waters and the atmosphere. Results showed that, during summer months, the bubble ebullition process strips and transports 1.9-4.8 percent/day of the standing crop of radon (and, by inference, other gases equilibrated with gas bubbles) in surface sediments of Cape Lookout Bight to the troposphere. Thus, the ebullitive mode of gas transport represents an effective mechanism for delivering reduced biogenic gases directly to the atmosphere.

  3. Coalbed methane production case histories

    SciTech Connect

    Not Available

    1981-02-01

    The production of methane gas from coal and coal-bearing rocks is one of the prime objectives of the Department of Energy's Methane Recovery from Coalbeds Project. This report contains brief description of wells that are presently producing gas from coal or coal-bearing rocks. Data from three gob gas production areas in Illinois, an in-mine horizontal borehole degasification, and eleven vertical boreholes are presented. Production charts and electric logs of the producing zones are included for some of the wells. Additional information on dry gas production from the San Juan Basin, Colorado/New Mexico and the Greater Green River Coal Region, Colorado/Wyoming is also included.

  4. Estimates for biogenic non-methane hydrocarbons and nitric oxide emissions in the Valley of Mexico

    NASA Astrophysics Data System (ADS)

    Velasco, Erik

    Biogenic non-methane hydrocarbons (NMHC), 2-methyl-3-buten-2-ol (methylbutenol or MBO) and nitrogen oxide (NO) emissions were estimated for the Valley of Mexico developing a spatially and temporally resolved emission inventory for air quality models. The modeling domain includes all the Metropolitan Mexico City Area, the surrounding forests and agriculture fields. The estimates were based on several sources of land use and land cover data and a biogenic emission model; the biomass density and tree characteristics were obtained from reforestation program data. The biogenic emissions depend also on climatic conditions, mainly temperature and solar radiation. The temperature was obtained from a statistical revision of the last 10 yr data reported by the Mexico City Automatic Atmospheric Monitoring Network, while the solar radiation data were obtained from measurements performed in a typical oak forest in the Valley and from sources of total solar radiation data for Mexico City. The results indicated that 7% of total hydrocarbon emissions in Mexico Valley are due to vegetation and NO emissions from soil contribute with 1% to the total NO x emissions.

  5. Archaebacterial Fuel Production: Methane from Biomass.

    ERIC Educational Resources Information Center

    Lennox, John E.; And Others

    1983-01-01

    Discusses microbial production of methane from biomass. Topics include methogens (bacteria producing methane), ecology of methanogenesis, methanogenesis in ruminant/nonruminant and other environments, role of methanogenesis in nature, and methane production in sewage treatment plants. Also discusses construction of methane digesters (and related…

  6. A 21st-century shift from fossil-fuel to biogenic methane emissions indicated by 13CH4

    NASA Astrophysics Data System (ADS)

    Schaefer, Hinrich; Fletcher, Sara E. Mikaloff; Veidt, Cordelia; Lassey, Keith R.; Brailsford, Gordon W.; Bromley, Tony M.; Dlugokencky, Edward J.; Michel, Sylvia E.; Miller, John B.; Levin, Ingeborg; Lowe, Dave C.; Martin, Ross J.; Vaughn, Bruce H.; White, James W. C.

    2016-04-01

    Between 1999 and 2006, a plateau interrupted the otherwise continuous increase of atmospheric methane concentration [CH4] since preindustrial times. Causes could be sink variability or a temporary reduction in industrial or climate-sensitive sources. We reconstructed the global history of [CH4] and its stable carbon isotopes from ice cores, archived air, and a global network of monitoring stations. A box-model analysis suggests that diminishing thermogenic emissions, probably from the fossil-fuel industry, and/or variations in the hydroxyl CH4 sink caused the [CH4] plateau. Thermogenic emissions did not resume to cause the renewed [CH4] rise after 2006, which contradicts emission inventories. Post-2006 source increases are predominantly biogenic, outside the Arctic, and arguably more consistent with agriculture than wetlands. If so, mitigating CH4 emissions must be balanced with the need for food production.

  7. A 21st-century shift from fossil-fuel to biogenic methane emissions indicated by ¹³CH₄.

    PubMed

    Schaefer, Hinrich; Mikaloff Fletcher, Sara E; Veidt, Cordelia; Lassey, Keith R; Brailsford, Gordon W; Bromley, Tony M; Dlugokencky, Edward J; Michel, Sylvia E; Miller, John B; Levin, Ingeborg; Lowe, Dave C; Martin, Ross J; Vaughn, Bruce H; White, James W C

    2016-04-01

    Between 1999 and 2006, a plateau interrupted the otherwise continuous increase of atmospheric methane concentration [CH4] since preindustrial times. Causes could be sink variability or a temporary reduction in industrial or climate-sensitive sources. We reconstructed the global history of [CH4] and its stable carbon isotopes from ice cores, archived air, and a global network of monitoring stations. A box-model analysis suggests that diminishing thermogenic emissions, probably from the fossil-fuel industry, and/or variations in the hydroxyl CH4 sink caused the [CH4] plateau. Thermogenic emissions did not resume to cause the renewed [CH4] rise after 2006, which contradicts emission inventories. Post-2006 source increases are predominantly biogenic, outside the Arctic, and arguably more consistent with agriculture than wetlands. If so, mitigating CH4 emissions must be balanced with the need for food production.

  8. Biogenic methane, hydrogen escape, and the irreversible oxidation of early Earth.

    PubMed

    Catling, D C; Zahnle, K J; McKay, C

    2001-08-03

    The low O2 content of the Archean atmosphere implies that methane should have been present at levels approximately 10(2) to 10(3) parts per million volume (ppmv) (compared with 1.7 ppmv today) given a plausible biogenic source. CH4 is favored as the greenhouse gas that countered the lower luminosity of the early Sun. But abundant CH4 implies that hydrogen escapes to space (upward arrow space) orders of magnitude faster than today. Such reductant loss oxidizes the Earth. Photosynthesis splits water into O2 and H, and methanogenesis transfers the H into CH4. Hydrogen escape after CH4 photolysis, therefore, causes a net gain of oxygen [CO2 + 2H2O --> CH4 + 2O2 --> CO2 + O2 + 4H(upward arrow space)]. Expected irreversible oxidation (approximately 10(12) to 10(13) moles oxygen per year) may help explain how Earth's surface environment became irreversibly oxidized.

  9. Measurements of biogenic non-methane organic compound emissions from grasslands

    SciTech Connect

    Fukui, Yoshiko

    1994-12-31

    Non-methane organic compounds (NMOCs) play an important role in the formation of photochemical oxidants in the troposphere. NMOCs originate from both anthropogenic and biogenic sources. Many organic compounds of biogenic origins are more reactive than those of anthropogenic origin because of the presence of internal double bonds within their molecular structure. The objective of this investigation was to examine the seasonal variation of NMOC emissions from grasslands and determine the environmental factors that control the emissions. An enclosure system was chosen as the most appropriate sampling technique for measuring emissions from herbaceous vegetation, and an analysis method using cryogenic preconcentration/high resolution gas chromatography was established. Emission rates were measured at a fixed location in a natural grassland during 1992 and 1993. Measurements were also made at various locations within the same site where the vegetation was harvested after the emission rates were determined. Emission rates of NMOCs for grasslands are not as large as those reported for forests. However the emissions of oxygenated hydrocarbons exceeded the emissions of monoterpenes and have not previously been identified as important forest-type emissions. A framework for parameterizing the NMOC emissions from grasslands based on seasonal and instantaneous variations of the emission rate measurements was developed. Temperature, hypoxia induced by water saturated soil, and frost were key environmental factors affecting both the composition and magnitude of NMOC emissions.

  10. The effect of coal bed dewatering and partial oxidation on biogenic methane potential

    USGS Publications Warehouse

    Jones, Elizabeth J.P.; Harris, Steve H.; Barnhart, Elliott P.; Orem, William H.; Clark, Arthur C.; Corum, Margo D.; Kirshtein, Julie D.; Varonka, Matthew S.; Voytek, Mary A.

    2013-01-01

    Coal formation dewatering at a site in the Powder River Basin was associated with enhanced potential for secondary biogenic methane determined by using a bioassay. We hypothesized that dewatering can stimulate microbial activity and increase the bioavailability of coal. We analyzed one dewatered and two water-saturated coals to examine possible ways in which dewatering influences coal bed natural gas biogenesis by looking at differences with respect to the native coal microbial community, coal-methane organic intermediates, and residual coal oxidation potential. Microbial biomass did not increase in response to dewatering. Small Subunit rRNA sequences retrieved from all coals sampled represented members from genera known to be aerobic, anaerobic and facultatively anaerobic. A Bray Curtis similarity analysis indicated that the microbial communities in water-saturated coals were more similar to each other than to the dewatered coal, suggesting an effect of dewatering. There was a higher incidence of long chain and volatile fatty acid intermediates in incubations of the dewatered coal compared to the water-saturated coals, and this could either be due to differences in microbial enzymatic activities or to chemical oxidation of the coal associated with O2 exposure. Dilute H2O2 treatment of two fractions of structural coal (kerogen and bitumen + kerogen) was used as a proxy for chemical oxidation by O2. The dewatered coal had a low residual oxidation potential compared to the water-saturated coals. Oxidation with 5% H2O2 did increase the bioavailability of structural coal, and the increase in residual oxidation potential in the water saturated coals was approximately equivalent to the higher methanogenic potential measured in the dewatered coal. Evidence from this study supports the idea that coal bed dewatering could stimulate biogenic methanogenesis through partial oxidation of the structural organics in coal once anaerobic conditions are restored.

  11. Re-assessing H and C Isotope Signatures of Biogenic Methane in Coalbeds and Shales: Metabolic Pathways and Alternative Influences

    NASA Astrophysics Data System (ADS)

    Vinson, D. S.; McIntosh, J. C.; Blair, N. E.; Martini, A. M.

    2013-12-01

    Hydrogen and carbon isotopes of microbial methane have long been applied to distinguish metabolic pathways of methanogenesis (utilization of acetate vs. H2+CO2 by methanogens). However, application of isotopic tools in hydrocarbon and biodegradation systems requires improved understanding of what is actually recorded by C and H isotopes of biogenic methane. Unlike culture studies where the fractionation factors of methanogenic pathways have been defined, field-collected gas or water samples represent net apparent isotope signatures influenced by a variety of overlapping water-rock-microbial interaction processes. Understanding these processes is important for modeling subsurface carbon cycling and biostimulation efforts for enhanced microbial gas production. Briefly, trends are apparent from a re-analysis of recently published water and gas isotope data from biogenic coalbed methane and shale gas systems: (1) δ13C-CH4 and the relationship between δ13C-CH4 and δ13C-CO2 (α13CCO2-CH4=(δ13C-CO2 + 1000)/(δ13C-CH4 +1000)), can also record the competition between methanogenesis and non-methanogenic processes (e.g. sulfate reduction), rather than simply recording the pathways of methanogenesis itself; and (2) Interpretation of δ2H-CH4 and δ2H-H2O can be inconsistent with δ13C-based fingerprinting techniques and indeed could be highly influenced by isotope exchange between water and methane precursors. This study provides an alternative approach for interpreting δ13C in shallow biogenic gas which considers that Corg may be consumed by competing, highly-fractionating and less-fractionating processes (e.g. methanogenesis and sulfate reduction, respectively). Whereas variation in apparent α13CCO2-CH4 could be inferred to indicate variation of metabolic pathways (that is, acetate fermentation vs. CO2 reduction) in some coalbed methane systems such as the Powder River Basin, the influx of sulfate relative to the overall Corg biodegradation rate could also be an

  12. Are methane production and cattle performance related?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methane is a product of fermentation of feed in ruminant animals. Approximately 2 -12% of the gross energy consumed by cattle is released through enteric methane production. There are three primary components that contribute to the enteric methane footprint of an animal. Those components are dry ...

  13. Discovery of Widespread Biogenic Methane Emissions and Authigenic Carbonate Mound-like Structures at the Aquitaine Shelf (Bay of Biscay)

    NASA Astrophysics Data System (ADS)

    Dupré, S.; Loubrieu, B.; Scalabrin, C.; Ehrhold, A.; Gautier, E.; Ruffine, L.; Pierre, C.; Battani, A.; Le Bouffant, N.; Berger, L.

    2014-12-01

    Fishery acoustic surveys conducted in the Bay of Biscay (1998-2012) and dedicated to monitoring and predicting pelagic ecosystem evolution reveal numerous active seeps on the Aquitaine Shelf, east of the shelf break (Dupré et al. 2014). Seafloor and water column acoustic investigation with the use of ship-borne multibeam echosounder in 2013 (Gazcogne1 marine expedition) confirmed the presence of numerous (> 3000) persistent and widespread gas emission sites at water depths ranging from ~140 to 180 m. These fluid emissions are associated at the seafloor with high backscatter subcircular small-scale mounds, on average less than 2 m high and a few meters in diameter. Near-bottom visual observations and samplings were conducted with the ROV (Remotely Operated Vehicle) Victor (Gazcogne2 expedition). The whole mounds cover an area of ~200 km2 of the seabed, and are by-products of gas seepage, i.e. methane-derived authigenic carbonates. The spatial distribution of the seeps and related structures, based on water column acoustic gas flares and high backscatter seabed patches, appears to be relatively broad, with a North-South extension of ~80 km across the Parentis Basin and the Landes High, and a West-East extension along a few kilometers wide on the shelf, up to 8 km. Gas bubbles sampled at in situ conditions are principally composed of biogenic methane, possibly originated from Late Pleistocene deposits. The volume of methane emitted into the water column is abundant i) with an average gas flux varying locally from 0.035 to 0.37 Ln/min and ii) with regard to the time needed for the precipitation of the authigenic carbonates identified both at the seabed and in the upper most sedimentary column. The GAZCOGNE study is co-funded by TOTAL and IFREMER as part of the PAMELA (Passive Margin Exploration Laboratories) scientific project. ReferenceDupré, S., Berger, L., Le Bouffant, N., Scalabrin, C., and Bourillet, J.-F., 2014. Fluid emissions at the Aquitaine Shelf (Bay of

  14. Microbial production and oxidation of methane in deep subsurface

    NASA Astrophysics Data System (ADS)

    Kotelnikova, Svetlana

    2002-10-01

    The goal of this review is to summarize present studies on microbial production and oxidation of methane in the deep subterranean environments. Methane is a long-living gas causing the "greenhouse" effect in the planet's atmosphere. Earlier, the deep "organic carbon poor" subsurface was not considered as a source of "biogenic" methane. Evidence of active methanogenesis and presence of viable methanogens including autotrophic organisms were obtained for some subsurface environments including water-flooded oil-fields, deep sandy aquifers, deep sea hydrothermal vents, the deep sediments and granitic groundwater at depths of 10 to 2000 m below sea level. As a rule, the deep subterranean microbial populations dwell at more or less oligotrophic conditions. Molecular hydrogen has been found in a variety of subsurface environments, where its concentrations were significantly higher than in the tested surface aquatic environments. Chemolithoautotrophic microorganisms from deep aquifers that could grow on hydrogen and carbon dioxide can act as primary producers of organic carbon, initiating heterotrophic food chains in the deep subterranean environments independent of photosynthesis. "Biogenic" methane has been found all over the world. On the basis of documented occurrences, gases in reservoirs and older sediments are similar and have the isotopic character of methane derived from CO 2 reduction. Groundwater representing the methanogenic end member are characterized by a relative depletion of dissolved organic carbon (DOC) in combination with an enrichment in 13C in inorganic carbon, which is consistent with the preferential reduction of 12CO 2 by autotrophic methanogens or acetogens. The isotopic composition of methane formed via CO 2 reduction is controlled by the δ13C of the original CO 2 substrate. Literature data shows that CH 4 as heavy as -40‰ or -50‰ can be produced by the microbial reduction of isotopically heavy CO 2. Produced methane may be oxidized

  15. Measuring Methane Production from Ruminants.

    PubMed

    Hill, Julian; McSweeney, Chris; Wright, André-Denis G; Bishop-Hurley, Greg; Kalantar-Zadeh, Kourosh

    2016-01-01

    Radiative forcing of methane (CH4) is significantly higher than carbon dioxide (CO2) and its enteric production by ruminant livestock is one of the major sources of greenhouse gas emissions. CH4 is also an important marker of farming productivity, because it is associated with the conversion of feed to product in livestock. Consequently, measurement of enteric CH4 is emerging as an important research topic. In this review, we briefly describe the conversion of carbohydrate to CH4 by the bacterial community within gut, and highlight some of the key host-microbiome interactions. We then provide a picture of current progress in techniques for measuring enteric CH4, the context in which these technologies are used, and the challenges faced. We also discuss solutions to existing problems and new approaches currently in development.

  16. Methane production by phosphate-starved SAR11 chemoheterotrophic marine bacteria.

    PubMed

    Carini, Paul; White, Angelicque E; Campbell, Emily O; Giovannoni, Stephen J

    2014-07-07

    The oxygenated surface waters of the world's oceans are supersaturated with methane relative to the atmosphere, a phenomenon termed the 'marine methane paradox'. The production of methylphosphonic acid (MPn) by marine archaea related to Nitrosopumilus maritimus and subsequent decomposition of MPn by phosphate-starved bacterioplankton may partially explain the excess methane in surface waters. Here we show that Pelagibacterales sp. strain HTCC7211, an isolate of the SAR11 clade of marine α-proteobacteria, produces methane from MPn, stoichiometric to phosphorus consumption, when starved for phosphate. Gene transcripts encoding phosphonate transport and hydrolysis proteins are upregulated under phosphate limitation, suggesting a genetic basis for the methanogenic phenotype. Strain HTCC7211 can also use 2-aminoethylphosphonate and assorted phosphate esters for phosphorus nutrition. Despite strain-specific differences in phosphorus utilization, these findings identify Pelagibacterales bacteria as a source of biogenic methane and further implicate phosphate starvation of chemoheterotrophic bacteria in the long-observed methane supersaturation in oxygenated waters.

  17. Biogenic Contributions to Aromatic Hydrocarbon Production over Continental North America

    NASA Astrophysics Data System (ADS)

    Sive, B. C.; Russo, R.; Zhou, Y.; Swarthout, R.; Hart, A.

    2011-12-01

    A comprehensive suite of temporally and vertically resolved volatile organic compound (VOC) measurements were conducted at the Boulder Atmospheric Observatory (BAO) in Erie, Colorado from 18 February to 13 March 2011 as part of the Nitrogen, Aerosol Composition, and Halogens on a Tall Tower (NACHTT) campaign. Specifically, this work investigates and quantifies the contribution of monoterpene oxidation to the secondary production of aromatic hydrocarbons and secondary organic aerosol (SOA) precursor gases. To date, this area of research has been largely unexplored; however, recent results from laboratory experiments have suggested that biogenic VOC (BVOC) oxidation should be considered as an important source of aromatic hydrocarbons, especially in rural and remote environments. The VOC measurements conducted during the NACHTT campaign provide diurnally and vertically resolved speciated monoterpene data over mid-latitude North America. New insight on biogenic emissions, their subsequent chemical transformations and influences on oxidant cycling will be explored.

  18. Biogenic production of dimethyl sulfide: Krill grazing

    SciTech Connect

    Daly, K.L.; DiTullio, G.R. )

    1993-01-01

    Dimethyl sulfide (DMS), a dominant sulfur compound in sea water, is a possible precursor for cloud condensation nuclei in the atmosphere and may influence global climate. The primary source of DMS is phytoplankton, but the mechanisms remain uncertain, and concentrations of DMS in the ocean vary spatially and temporally. Laboratory studies suggest zooplankton grazing may be an important process leading to the formation of DMS in the ocean. This paper describes ocean studies which examine the suggestion that grazing by krill may be a significant source for DMS production in the antarctic coastal region. 11 refs., 2 figs.

  19. Separating methane emissions from biogenic sources and natural gas by vertical column enhancements of ammonia, ethane, and methane in the Colorado Front Range

    NASA Astrophysics Data System (ADS)

    Chiu, R.; Volkamer, R. M.; Blumenstock, T.; Hase, F.; Hannigan, J. W.; Kille, N.; Frey, M.; Kumar Sha, M.; Orphal, J.

    2015-12-01

    Methane sources in the Colorado Front Range include biogenic sources from cattle feedlots and natural gas operations. Although numerous studies have measured methane emissions, there remains significant uncertainty regarding the relative contributions of these various methane emission sources. Here we present data from a March 2015 field campaign that deployed two Bruker EM27 Sun Fourier Transform Spectrometers (FTS) and the University of Colorado Solar Occultation Flux (CU-SOF) FTS in Eaton, Colorado; the former were used to measure enhancements in the methane vertical column densities (VCD), while the latter was used to measure ethane and ammonia VCDs. A third EM27 FTS was deployed to a background site in Westminster, Colorado which was far removed from cattle and petroleum operations. Northerly winds make possible the determination of methane VCD column enhancement from Westminster to Eaton. All instruments were compared during several background days at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado. This presentation explores the potential of methane source attribution using ammonia as a tracer for feedlot emissions and ethane as a tracer for petroleum emissions.

  20. Factors Influencing Biogenic Amines Accumulation in Dairy Products

    PubMed Central

    Linares, Daniel M.; del Río, Beatriz; Ladero, Victor; Martínez, Noelia; Fernández, María; Martín, María Cruz; Álvarez, Miguel A.

    2012-01-01

    Fermented foods are among the food products more often complained of having caused episodes of biogenic amines (BA) poisoning. Concerning milk-based fermented foods, cheese is the main product likely to contain potentially harmful levels of BA, specially tyramine, histamine, and putrescine. Prompted by the increasing awareness of the risks related to dietary uptake of high biogenic amine loads, in this review we report all those elaboration and processing technological aspects affecting BA biosynthesis and accumulation in dairy foods. Improved knowledge of the factors involved in the synthesis and accumulation of BA should lead to a reduction in their incidence in milk products. Synthesis of BA is possible only when three conditions converge: (i) availability of the substrate amino acids; (ii) presence of microorganisms with the appropriate catabolic pathway activated; and (iii) environmental conditions favorable to the decarboxylation activity. These conditions depend on several factors such as milk treatment (pasteurization), use of starter cultures, NaCl concentration, time, and temperature of ripening and preservation, pH, temperature, or post-ripening technological processes, which will be discussed in this chapter. PMID:22783233

  1. Abiotic production of methane in terrestrial planets.

    PubMed

    Guzmán-Marmolejo, Andrés; Segura, Antígona; Escobar-Briones, Elva

    2013-06-01

    On Earth, methane is produced mainly by life, and it has been proposed that, under certain conditions, methane detected in an exoplanetary spectrum may be considered a biosignature. Here, we estimate how much methane may be produced in hydrothermal vent systems by serpentinization, its main geological source, using the kinetic properties of the main reactions involved in methane production by serpentinization. Hydrogen production by serpentinization was calculated as a function of the available FeO in the crust, given the current spreading rates. Carbon dioxide is the limiting reactant for methane formation because it is highly depleted in aqueous form in hydrothermal vent systems. We estimated maximum CH4 surface fluxes of 6.8×10(8) and 1.3×10(9) molecules cm(-2) s(-1) for rocky planets with 1 and 5 M⊕, respectively. Using a 1-D photochemical model, we simulated atmospheres with volume mixing ratios of 0.03 and 0.1 CO2 to calculate atmospheric methane concentrations for the maximum production of this compound by serpentinization. The resulting abundances were 2.5 and 2.1 ppmv for 1 M⊕ planets and 4.1 and 3.7 ppmv for 5 M⊕ planets. Therefore, low atmospheric concentrations of methane may be produced by serpentinization. For habitable planets around Sun-like stars with N2-CO2 atmospheres, methane concentrations larger than 10 ppmv may indicate the presence of life.

  2. Authigenic carbonate mounds from active methane seeps on the southern Aquitaine Shelf (Bay of Biscay, France): Evidence for anaerobic oxidation of biogenic methane and submarine groundwater discharge during formation

    NASA Astrophysics Data System (ADS)

    Pierre, Catherine; Demange, Jérome; Blanc-Valleron, Marie-Madeleine; Dupré, Stéphanie

    2017-02-01

    The widespread methane emissions that were discovered in 2013 on the Aquitaine Shelf at water depth between 140 and 220 m are associated with authigenic carbonate crusts that cover meter-high subcircular reliefs of 10-100 m in diameter. These authigenic carbonates are primarily aragonite plus calcite and dolomite, which cement the fine- to medium-grained sandy sediment. The carbonate cement is often pierced by numerous circular cavities of 5-10 μm in diameter that are considered to be moulds of gas bubbles. Conversely, micron-sized cavities in the aragonite crystals are attributed to dissolution features, in relation to the production of CO2 during the aerobic oxidation of methane. The oxygen isotopic compositions of bulk carbonate (+1.7 to +3.7‰) and aragonite cements obtained from microsampling (-0.1 to +1.4‰) indicate that these carbonates were precipitated in mixtures of seawater and freshwater, i.e., in the context of submarine groundwater discharge at the seafloor. The carbon isotopic compositions of authigenic carbonates (-51.9 to -38.1‰) and of aragonite cements (-49.9 to -29.3‰) show that the dissolved inorganic carbon of pore fluids was mostly produced by the anaerobic oxidation of biogenic methane and also partly from the groundwater system.

  3. Methane production by attached film

    DOEpatents

    Jewell, William J.

    1981-01-01

    A method for purifying wastewater of biodegradable organics by converting the organics to methane and carbon dioxide gases is disclosed, characterized by the use of an anaerobic attached film expanded bed reactor for the reaction process. Dilute organic waste material is initially seeded with a heterogeneous anaerobic bacteria population including a methane-producing bacteria. The seeded organic waste material is introduced into the bottom of the expanded bed reactor which includes a particulate support media coated with a polysaccharide film. A low-velocity upward flow of the organic waste material is established through the bed during which the attached bacterial film reacts with the organic material to produce methane and carbon dioxide gases, purified water, and a small amount of residual effluent material. The residual effluent material is filtered by the film as it flows upwardly through the reactor bed. In a preferred embodiment, partially treated effluent material is recycled from the top of the bed to the bottom of the bed for further treatment. The methane and carbon dioxide gases are then separated from the residual effluent material and purified water.

  4. Abiotic Production of Methane in Terrestrial Planets

    PubMed Central

    Guzmán-Marmolejo, Andrés; Escobar-Briones, Elva

    2013-01-01

    Abstract On Earth, methane is produced mainly by life, and it has been proposed that, under certain conditions, methane detected in an exoplanetary spectrum may be considered a biosignature. Here, we estimate how much methane may be produced in hydrothermal vent systems by serpentinization, its main geological source, using the kinetic properties of the main reactions involved in methane production by serpentinization. Hydrogen production by serpentinization was calculated as a function of the available FeO in the crust, given the current spreading rates. Carbon dioxide is the limiting reactant for methane formation because it is highly depleted in aqueous form in hydrothermal vent systems. We estimated maximum CH4 surface fluxes of 6.8×108 and 1.3×109 molecules cm−2 s−1 for rocky planets with 1 and 5 M⊕, respectively. Using a 1-D photochemical model, we simulated atmospheres with volume mixing ratios of 0.03 and 0.1 CO2 to calculate atmospheric methane concentrations for the maximum production of this compound by serpentinization. The resulting abundances were 2.5 and 2.1 ppmv for 1 M⊕ planets and 4.1 and 3.7 ppmv for 5 M⊕ planets. Therefore, low atmospheric concentrations of methane may be produced by serpentinization. For habitable planets around Sun-like stars with N2-CO2 atmospheres, methane concentrations larger than 10 ppmv may indicate the presence of life. Key Words: Serpentinization—Exoplanets—Biosignatures—Planetary atmospheres. Astrobiology 13, 550–559. PMID:23742231

  5. Methane dynamics in a montane fen: Factors controlling production, accumulation and emissions

    NASA Astrophysics Data System (ADS)

    Mwakanyamale, K. E.; Yeung, H.; Strack, M.

    2014-12-01

    Characterization of methane dynamics in peatlands is essential to improve understanding of peatlands contribution to carbon balance and interaction with climate. Of the two peatland types, natural fens are known to be a larger contributor of methane emissions to the atmosphere than natural bogs. This study uses geophysical methods integrated with in-situ direct measurements and chamber fluxes to improve understanding of temporal and spatial variation in methane production, accumulation and emissions from natural montane fen in Alberta Canada. Meteorological data and peat cores (~150 cm) were collected to study factors affecting methane production, accumulation and emissions from the Sibbald Research Wetland, a montane fen in the Rocky Mountains in southern Alberta. Our results show a direct correlation between methane accumulation and degree of peat humification, substrate quality and porosity. Changes in temperature, pressure and water table position were shown to relate to ebullition events, with the highest number of ebullition events occurring from late August to early November. The geophysical results indicate a small spatial variation in free phase biogenic gas accumulation within the studied area. Diffusive methane fluxes were correlated to plant productivity on both daily and seasonal time scales with patterns varying between plots dominated by Juncus sp. and Carex spp. These results highlight the interacting ecological and physical controls on peatland methane dynamics.

  6. Estimating methane gas production in peat soils of the Florida Everglades using hydrogeophysical methods

    NASA Astrophysics Data System (ADS)

    Wright, William; Comas, Xavier

    2016-04-01

    The spatial and temporal variability in production and release of greenhouse gases (such as methane) in peat soils remains uncertain, particularly for low-latitude peatlands like the Everglades. Ground penetrating radar (GPR) is a hydrogeophysical tool that has been successfully used in the last decade to noninvasively investigate carbon dynamics in peat soils; however, application in subtropical systems is almost non-existent. This study is based on four field sites in the Florida Everglades, where changes in gas content within the soil are monitored using time-lapse GPR measurements and gas releases are monitored using gas traps. A weekly methane gas production rate is estimated using a mass balance approach, considering gas content estimated from GPR, gas release from gas traps and incorporating rates of diffusion, and methanotrophic consumption from previous studies. Resulting production rates range between 0.02 and 0.47 g CH4 m-2 d-1, falling within the range reported in literature. This study shows the potential of combining GPR with gas traps to monitor gas dynamics in peat soils of the Everglades and estimate methane gas production. We also show the enhanced ability of certain peat soils to store gas when compared to others, suggesting that physical properties control biogenic gas storage in the Everglades peat soils. Better understanding biogenic methane gas dynamics in peat soils has implications regarding the role of wetlands in the global carbon cycle, particularly under a climate change scenario.

  7. Sulfide and methane production in sewer sediments.

    PubMed

    Liu, Yiwen; Ni, Bing-Jie; Ganigué, Ramon; Werner, Ursula; Sharma, Keshab R; Yuan, Zhiguo

    2015-03-01

    Recent studies have demonstrated significant sulfide and methane production by sewer biofilms, particularly in rising mains. Sewer sediments in gravity sewers are also biologically active; however, their contribution to biological transformations in sewers is poorly understood at present. In this study, sediments collected from a gravity sewer were cultivated in a laboratory reactor fed with real wastewater for more than one year to obtain intact sediments. Batch test results show significant sulfide production with an average rate of 9.20 ± 0.39 g S/m(2)·d from the sediments, which is significantly higher than the areal rate of sewer biofilms. In contrast, the average methane production rate is 1.56 ± 0.14 g CH4/m(2)·d at 20 °C, which is comparable to the areal rate of sewer biofilms. These results clearly show that the contributions of sewer sediments to sulfide and methane production cannot be ignored when evaluating sewer emissions. Microsensor and pore water measurements of sulfide, sulfate and methane in the sediments, microbial profiling along the depth of the sediments and mathematical modelling reveal that sulfide production takes place near the sediment surface due to the limited penetration of sulfate. In comparison, methane production occurs in a much deeper zone below the surface likely due to the better penetration of soluble organic carbon. Modelling results illustrate the dependency of sulfide and methane productions on the bulk sulfate and soluble organic carbon concentrations can be well described with half-order kinetics.

  8. Estimating the biogenic emissions of non-methane volatile organic compounds from the North Western Mediterranean vegetation of Catalonia, Spain.

    PubMed

    Parra, R; Gassó, S; Baldasano, J M

    2004-08-15

    An estimation of the magnitude of non-methane volatile organic compounds (NMVOCs) emitted by vegetation in Catalonia (NE of the Iberian Peninsula, Spain), in addition to their superficial and temporal distribution, is presented for policy and scientific (photochemical modelling) purposes. It was developed for the year 2000, for different time resolutions (hourly, daily, monthly and annual) and using a high-resolution land-use map (1-km2 squared cells). Several meteorological surface stations provided air temperature and solar radiation data. An adjusted mathematical emission model taking account of Catalonia's conditions was built into a geographic information system (GIS) software. This estimation uses the latest information, mainly relating to: (1) emission factors; (2) better knowledge of the composition of Catalonia's forest cover; and (3) better knowledge of the particular emission behaviour of some Mediterranean vegetal species. Results depict an annual cycle with increasing values in the March-April period with the highest emissions in July-August, followed by a decrease in October-November. Annual biogenic NMVOCs emissions reach 46.9 kt, with monoterpenes the most abundant species (24.7 kt), followed by other biogenic volatile organic compounds (e.g. alcohols, aldehydes and acetone) (16.3 kt), and isoprene (5.9 kt). These compounds signify 52%, 35% and 13%, respectively, of total emission estimates. Peak hourly total emission for a winter day could be less than 10% of the corresponding value for a summer day.

  9. Methanogens and Martian natural resources: Investigations regarding the possibility of biogenic methane on Mars

    NASA Astrophysics Data System (ADS)

    Chastain, Brendon Kelly

    Archaeal methanogens were suggested as terrestrial models of possible subsurface martian microbial life prior to the actual detection of methane in Mars' atmosphere. This idea gained even more interest after the methane on Mars was observed. However, the amount of methane detected was very small, and release of methane was localized and episodic. This led some scientists to doubt that an active or ancient biosphere could be the source of the methane. Moreover, even extremophilic methanogens have not been shown to metabolize in conditions exactly analogous to those known to be available on Mars. The following chapters present a realistic and viable mechanism that allows a large or ancient biosphere to be the original source of the observed methane, and they detail experimental work that was done in order to systematically investigate nutritional and conditional variables related to those that might be available in the martian subsurface. The results of the experimental work indicate that some components of Mars' regolith can support methanogenic metabolism without being detrimental to the organisms, and that certain known components of Mars' regolith can promote periods of methanogenic dormancy without being lethal to the methanogens. The results of the experimental studies also show that material known to exist at and near Mars' surface has the potential to supply electrons for biological methanogenesis and that methanogenic metabolism can occur even when artificial media, buffers, and reductants are omitted in order to create more Mars-relevant conditions. These findings may have implications regarding the viability of methanogenic organisms as a source of the observed methane and should assist future efforts to study methanogenic metabolism in conditions exactly analogous to those available in niches on Mars.

  10. Methane production from ozonated pulp mill effluent

    SciTech Connect

    Bremmon, C.E.; Jurgensen, M.F.; Patton, J.T.

    1980-07-01

    A study was made of the production of methane from desugared spent sulfite liquor (SSL) reacted with ozone. The ozonated SSL was fed continuously to three anaerobic fermenters for three months as the sole source of carbon and energy. The fermenters were inoculated with anaerobic bacteria obtained from sewage sludge and acclimated for 1 month in ozonated SSL prior to continuous fermentation. Chemical and biological parameters such as COD, BOD, total sulfur content, redox potential, pH, fatty acid composition, and methane bacteria populations were monitored to determine changes in the SSL during fermentation. Methane production from ozone-treated SSL averaged 1.7 liters/ liter or 17 ml of CH/sub 4/ produced/gram of volatile solids fed. Fatty acis analysis of fermenter effluent indicated a net production of 58 mM/ liter of acetate during ozonated SSL fermentation. This acetic acid production shows future potential for further fermentation by protein-producing yeast. Although the rate of conversion of volatile solids to CH/sub 4/ in this process was not competitive with domestic or agricultural waste digesters, this study did indicate the potential benefits of ozonating organic wastes for increased methane fermentation yields.

  11. Biogenic carbon fluxes from global agricultural production and consumption

    SciTech Connect

    Wolf, Julie; West, Tristram O.; Le Page, Yannick LB; Kyle, G. Page; Zhang, Xuesong; Collatz, George; Imhoff, Marc L.

    2015-10-01

    Quantification of biogenic carbon fluxes from agricultural lands is needed to generate comprehensive bottom-up estimates of net carbon exchange for global and regional carbon monitoring. We estimated global agricultural carbon fluxes associated with annual crop net primary production (NPP), harvested biomass, and consumption of biomass by humans and livestock. These estimates were combined for a single estimate of net carbon exchange (NCE) and spatially distributed to 0.05 degree resolution using MODIS satellite land cover data. Global crop NPP in 2011 was estimated at 5.25 ± 0.46 Pg C yr-1, of which 2.05 ± 0.05 Pg C yr-1 was harvested and 0.54 Pg C yr-1 was collected from crop residues for livestock fodder. Total livestock feed intake in 2011 was 2.42 ± 0.21 Pg C yr-1, of which 2.31 ± 0.21 Pg C yr-1 was emitted as CO2, 0.07 ± 0.01 Pg C yr-1 was emitted as CH4, and 0.04 Pg C yr-1 was contained within milk and egg production. Livestock grazed an estimated 1.27 Pg C yr-1 in 2011, which constituted 52.4% of total feed intake. Global human food intake was 0.57 ± 0.03 Pg C yr-1 in 2011, the majority of which is respired as CO2. Completed global cropland carbon budgets accounted for the ultimate use of ca. 80% of harvested biomass. The spatial distribution of these fluxes may be used for global carbon monitoring, estimation of regional uncertainty, and for use as input to Earth system models.

  12. Contemporary and projected biogenic fluxes of methane and nitrous oxide in North American terrestrial ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The importance of methane (CH4) and nitrous oxide (N2O) in determining global climate change has been increasingly recognized, but terrestrial CH4 and N2O budgets and the underlying mechanisms remain far from certain. Accurate estimation of terrestrial CH4 and N2O budgets would be a critical step fo...

  13. Potential methane production and methane oxidation rates in peatland ecosystems of the Appalachian Mountains, United States

    SciTech Connect

    Yavitt, J.B.; Lang, G.E.; Downey, D.M. )

    1988-09-01

    Potential rates of methane production and carbon dioxide production were measured on 11 dates in 1986 in peat from six plant communities typical of moss-dominated peatlands in the Appalachian Mountains. Annual methane production ranged from 2.7 to 17.5 mol/sq m, and annual carbon dioxide production ranged from 30.6 to 79.0 mol/sq m. The wide range in methane production values among the communities found within a single peatland indicates that obtaining one production value for a peatland may not be appropriate. Low temperature constrained the potential for methane production in winter, while the chemical quality of the peat substrate appears to control methane production in the summer. Methane oxidation was measured throughout the peat profile to a depth of 30 cm. Values for methane oxidation ranged from 0.08 to 18.7 microM/hr among the six plant communities. Aerobic methane-oxidizing bacteria probably mediated most of the activity. On a daily basis during the summer, between 11 and 100% of the methane produced is susceptible to oxidation within the peat column. Pools of dissolved methane and dissolved carbon dioxide in pore waters were less than 0.2 and less than 1.0 mol/sq m, respectively, indicating that methane does not accumulate in the pore waters. Peatlands have been considered as an important source of biologically produced methane. Despite the high rates of methane production, the high rates of methane oxidation dampen the potential emission of methane to the atmosphere. 41 refs., 7 figs., 4 tabs.

  14. Microbial methane production in deep aquifer associated with the accretionary prism in Japan.

    PubMed

    Kimura, Hiroyuki; Nashimoto, Hiroaki; Shimizu, Mikio; Hattori, Shohei; Yamada, Keita; Koba, Keisuke; Yoshida, Naohiro; Kato, Kenji

    2010-04-01

    To identify the methanogenic pathways present in a deep aquifer associated with an accretionary prism in Southwest Japan, a series of geochemical and microbiological studies of natural gas and groundwater derived from a deep aquifer were performed. Stable carbon isotopic analysis of methane in the natural gas and dissolved inorganic carbon (mainly bicarbonate) in groundwater suggested that the methane was derived from both thermogenic and biogenic processes. Archaeal 16S rRNA gene analysis revealed the dominance of H(2)-using methanogens in the groundwater. Furthermore, the high potential of methane production by H(2)-using methanogens was shown in enrichments using groundwater amended with H(2) and CO(2). Bacterial 16S rRNA gene analysis showed that fermentative bacteria inhabited the deep aquifer. Anaerobic incubations using groundwater amended with organic substrates and bromoethanesulfonate (a methanogen inhibitor) suggested a high potential of H(2) and CO(2) generation by fermentative bacteria. To confirm whether or not methane is produced by a syntrophic consortium of H(2)-producing fermentative bacteria and H(2)-using methanogens, anaerobic incubations using the groundwater amended with organic substrates were performed. Consequently, H(2) accumulation and rapid methane production were observed in these enrichments incubated at 55 and 65 degrees C. Thus, our results suggested that past and ongoing syntrophic biodegradation of organic compounds by H(2)-producing fermentative bacteria and H(2)-using methanogens, as well as a thermogenic reaction, contributes to the significant methane reserves in the deep aquifer associated with the accretionary prism in Southwest Japan.

  15. Methane production and simultaneous sulphate reduction in anoxic, salt marsh sediments

    USGS Publications Warehouse

    Oremland, R.S.; Marsh, L.M.; Polcin, S.

    1982-01-01

    It has been generally believed that sulphate reduction precludes methane generation during diagenesis of anoxic sediments1,2. Because most biogenic methane formed in nature is thought to derive either from acetate cleavage or by hydrogen reduction of carbon dioxide3-6, the removal of these compounds by the energetically more efficient sulphate-reducing bacteria can impose a substrate limitation on methanogenic bacteria 7-9. However, two known species of methanogens, Methanosarcina barkeri and Methanococcus mazei, can grow on and produce methane from methanol and methylated amines10-13. In addition, these compounds stimulate methane production by bacterial enrichments from the rumen11,14 and aquatic muds13,14. Methanol can enter anaerobic food webs through bacterial degradation of lignins15 or pectin16, and methylated amines can be produced either from decomposition of substances like choline, creatine and betaine13,14 or by bacterial reduction of trimethylamine oxide17, a common metabolite and excretory product of marine animals. However, the relative importance of methanol and methylated amines as precursors of methane in sediments has not been previously examined. We now report that methanol and trimethylamine are important substrates for methanogenic bacteria in salt marsh sediments and that these compounds may account for the bulk of methane produced therein. Furthermore, because these compounds do not stimulate sulphate reduction, methanogenesis and sulphate reduction can operate concurrently in sulphate-containing anoxic sediments. ?? 1982 Nature Publishing Group.

  16. Escape paths for biogenic methane gas in lake sediments: morphology and dynamics

    NASA Astrophysics Data System (ADS)

    Scandella, B. P.; Hemond, H.; Ruppel, C. D.; Juanes, R.

    2011-12-01

    Methane is a potent greenhouse gas that is generated geothermally and biologically in lake and ocean sediments. Free gas bubbles grow in saturated pore water and escape more readily as the absolute pressure (due to changes in water level or atmospheric pressure) falls, but neither the morphology of gas flow paths nor the dynamics controlling them have been well-constrained. We present laboratory experiments in which methanogens are incubated in lacustrine sediments and the subsequent gas release is triggered by hydrostatic unloading. Image analysis shows the morphology and persistence of the network of gas release paths, and records of the pressures and stresses help to identify the dynamics that control ebullition from gassy sediments. This work is fundamental to constraining the parameterization of large-scale models of methane venting from submerged, organic-rich sediments.

  17. Methane production by sheep and cattle in Australia

    NASA Astrophysics Data System (ADS)

    Minson, D. J.

    1993-02-01

    Using methane production rates from Australian feeds and local estimates of the quantity of feed eaten by different classes of animal, it was estimated that sheep and cattle in Australia produce 2.66 Tg methane in 1990. This value is 43% higher than previous estimates and indicates a need to reassess the methane production of ruminants in other countries.

  18. Methane production from ethanol co-products in anaerobic SBRs.

    PubMed

    Cassidy, D P; Hirl, P J; Belia, E

    2008-01-01

    Methane production from condensed distillers' solubles (CDS, or syrup), a co-product of ethanol production, was studied in 2-l anaerobic sequencing batch reactors (ASBRs) under 10 different operating conditions. Methane production and COD removal were quantified under steady state conditions for a wide range of operating parameters. COD removals of 62-96% were achieved at OLRs ranging from 1.5-22.2 g COD l(-1) d(-1), SRTs from 8-40 d, and F/M ranging from 0.37-1.95 g COD g(-1) VSS d(-1). The methane content of the biogas varied from 57-71% with 0.27 l CH(4) produced per g of COD removed. Approximately 54% of the COD fed to the ASBRs, and 83% of the COD removed in the ASBRs was converted to methane. Microbial yield (Y) and decay (b) constants were determined to be approximately Y = 0.127 g VSS g(-1) COD removed and b = 0.031 d(-1), respectively. Methane recovery from ethanol co-products can reduce the cost and the fossil fuel consumption of ethanol production.

  19. Identification of Methanogens and Controls on Methane Production in Incubations of Natural Methane Seep Sediments

    NASA Astrophysics Data System (ADS)

    Kevorkian, R.; Lloyd, K. G.

    2014-12-01

    Methane, the most abundant hydrocarbon in Earth's atmosphere, is produced in large quantities in sediments underlying the world's oceans. Very little of this methane makes it to surface sediments as it is consumed by Anaerobic Methanotrophs (ANME's) in consortia with Sulfate Reducing Bacteria (SRB). Less is known about which organisms are responsible for methane production in marine sediments, and whether that production is under thermodynamic control based on hydrogen concentrations. Although ANMEs have been found to be active in methanogenic sediments and incubations, it is currently unknown whether they are able to grow in methanogenic conditions. We demonstrated with bottle incubations of methane seep sediment taken from Cape Lookout Bight, NC, that hydrogen controls methane production. While sulfate was present the hydrogen concentration was maintained at below 2 nM. Only after the depletion of sulfate allowed hydrogen concentrations to rise above 5 nM did we see production of methane. The same sediments when spiked with methane gas demonstrated its complete removal while sulfate reduction occurred. Quantitative PCR shows that ANME-2 and ANME-1 increase in 16S copy number as methane increases. Total direct cell counts demonstrate a decline in cells with the decrease of sulfate until a recovery corresponding with production of methane. Our results strongly suggest that hydrogen concentrations influence what metabolic processes can occur in marine sediments, and that ANME-1 and ANME-2 are able to grow on the energy provided from methane production.

  20. Comparison of biogenic methane emissions from unmanaged estuaries, lakes, oceans, rivers and wetlands

    NASA Astrophysics Data System (ADS)

    Ortiz-Llorente, M. J.; Alvarez-Cobelas, M.

    2012-11-01

    A literature review of quantitative data was carried out to conduct a cross-system study on methane emissions relating peak emissions (PE) and annual emissions (AE) in five types of non-managed ecosystems: estuaries, lakes, oceans, streams and wetlands. PE spanned eight orders of magnitude (0.015 μg CH4 m-2 h-1-300 mg CH4 m-2 h-1) while AE spanned seven (0.078-19044 g CH4 m-2 yr-1). PE and AE were strongly related worldwide (r2 = 0.93). There was no relationship between AE and latitude, with highly variable PE across latitudes and climates. The coefficient of variation (CV) was greatest for emissions in oceans and estuaries, while the highest emission rate was recorded in wetlands and lakes. Efflux from coastal areas and estuaries was higher than that from upwelling areas and deep seas. Concerning wetland types, marshes showed the highest PE with the highest wetland emissions occurring in sites dominated by big helophytes. Non-stratifying- and eutrophic lakes displayed more emissions than other lake types, but there was no environmental variable that might predict methane emissions from lakes on a worldwide basis. Generally, most ecosystem types followed a seasonal pattern of emissions, with a maximum in summer, except in estuaries which did not show any distinct pattern. Regarding the importance of hot spots within most ecosystems, more spatial variability of CH4 emissions was observed in lakes than in wetlands and oceans; however, no relationship between emissions and spatial variability was found. A positive relationship, albeit weak, was found between methane flux and either temperature or irradiance in wetlands; a narrow range of both negative and positive values of the water table promoted CH4 emissions. Previously, little was known about the factors controlling efflux from river and marine environments. Our study suggests that local conditions are important in controlling CH4 emissions, because the variability explained by the more commonly studied abiotic

  1. Changes in Methane Production Pathway as a Function of Nutrient Input in the Florida Everglades

    NASA Astrophysics Data System (ADS)

    Holmes, M.; Chanton, J.; Bae, H.; Ogram, A.

    2011-12-01

    The relative importance of acetotrophic and hydrogenotrophic methanogenic pathways was evaluated at a study site along a nutrient gradient in the Florida Everglades. A better understanding of the impact of nutrient loading on methanogenesis in wetlands is critical because methane production in wetlands is an important part of the global methane budget. The isotopic composition of biogenic CH4 is affected by the relative contribution of each methanogenic pathway because a larger isotope effect is associated with hydrogenotrophic methane production than acetoclastic methanogenesis. δ13C of CH4 and CO2 in porewater from three sites in the northern Everglades indicated that a higher proportion of methane was produced via hydrogenotrophic methanogenesis at the nutrient-impacted site than at the oligotrophic site. δ13C- CH4 was -64%, on average, at the eutrophic site and was around -50% at the oligotrophic site. Likewise, the apparent fractionation factors between CH4 and CO2 were higher at the nutrient impacted sites than at the oligotrophic site, indicating that more of the CH4 produced at the eutrophic site came from hydrogenotrophic methanogenesis. Soils from the same sites were incubated with methyl fluoride, an inhibitor of acetoclastic methanogenesis, and δ13C- CH4 and δ13C- CO2 in these soils was compared with soil incubated without the inhibitor. Apparent fractionation factors in soils where only the hydrogenotrophic pathway was active were higher and less CH4 was produced than in soils in which both pathways proceeded. Blocking the production of methane via acetate fermentation allowed us to estimate that about 70% of the methane produced in soils from the oligotrophic site was from acetate fermentation and 70 to 80% was from CO2 reduction in the most nutrient impacted soil. These results demonstrate the effect that nutrient levels can have on methane production in natural wetlands.

  2. Aerobic methane production from organic matter

    NASA Astrophysics Data System (ADS)

    Vigano, I.

    2010-01-01

    Methane, together with H2O, CO2 and N2O, is an important greenhouse gas in th e Earth’s atmosphere playing a key role in the radiative budget. It has be en known for decades that the production of the reduced compound CH4 is possible almost exclusively in anoxic environments per opera of one of the most importan t class of microorganisms which form the Archaea reign. Methane can be produced also from incomplete combustion of organic material. The generation of CH4 in an oxygenated environment under near-ambient conditions is a new discovery made in 2006 by Keppler et. al where surprisingly they measured emissions of this green house gas from plants incubated in chambers with air containing 20% of oxygen. A lthough the estimates on a global scale are still object of an intensive debate, the results presented in this thesis clearly show the existence of methane prod uction under oxic conditions for non living plant material. Temperature and UV l ight are key factors that drive the generation of CH4 from plant matter in a wel l oxygenated environment.

  3. Methane production by anaerobic digestion of water hyacinth (Eichhornia crassipes)

    SciTech Connect

    Klass, D.L.; Ghosh, S.

    1980-01-01

    Water hyacinth under conventional high-rate digestion conditions exhibited higher methane yields and energy recovery efficiencies when grown in sewage-fed lagoons as compared to the corresponding values obtained with water hyacinth grown in a fresh-water pond. Mesophilic digestion provided the highest feed energy recovered in the product gas as methane while thermophilic digestion, when operated at sufficiently high loading rates and reduced detention times, gave the highest specific methane production rates. Methane yields, volatile solids reduction, and energy recovery as methane for the sewage-grown water hyacinth were in the same range as those observed for other biomass substrates when digested under similar conditions.

  4. Dry fermented sausages of Southern Italy: a comparison of free amino acids and biogenic amines between industrial and homemade products.

    PubMed

    Leggio, Antonella; Belsito, Emilia L; De Marco, Rosaria; Di Gioia, Maria L; Liguori, Angelo; Siciliano, Carlo; Spinella, Mariagiovanna

    2012-04-01

    This paper compares some important parameters and the free amino acid and biogenic amine contents of cured industrial and homemade meat products. To this aim, industrial and homemade "soppressata" and "salsiccia", typical dry fermented sausages produced in Southern Italy, were analyzed. The homemade sausages showed a higher level of free biogenic amines than that manufactured industrially, most likely because biogenic amine formation in industrial products is limited by the use of starter cultures. The industrial sausages are characterized by a higher total free amino acid content than the homemade products. Overall, free amino acid and biogenic amine contents demonstrated that appreciable differences exist between homemade and industrial sausages.

  5. A model for methane production in sewers.

    PubMed

    Chaosakul, Thitirat; Koottatep, Thammarat; Polprasert, Chongrak

    2014-09-19

    Most sewers in developing countries are combined sewers which receive stormwater and effluent from septic tanks or cesspools of households and buildings. Although the wastewater strength in these sewers is usually lower than those in developed countries, due to improper construction and maintenance, the hydraulic retention time (HRT) could be relatively long and resulting considerable greenhouse gas (GHG) production. This study proposed an empirical model to predict the quantity of methane production in gravity-flow sewers based on relevant parameters such as surface area to volume ratio (A/V) of sewer, hydraulic retention time (HRT) and wastewater temperature. The model was developed from field survey data of gravity-flow sewers located in a peri-urban area, central Thailand and validated with field data of a sewer system of the Gold Coast area, Queensland, Australia. Application of this model to improve construction and maintenance of gravity-flow sewers to minimize GHG production and reduce global warming is presented.

  6. Methyl Chavicol: Characterization of its Biogenic Emission Rate, Abundance, and Oxidation Products in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Bouvier-Brown, N. C.; Goldstein, A. H.; Worton, D. R.; Matross, D. M.; Gilman, J.; Kuster, W.; Degouw, J.; Cahill, T. M.; Holzinger, R.

    2008-12-01

    We report quantitative measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments: gas chromatograph with mass spectrometer detector (GC-MS), proton transfer reaction mass spectrometer (PTR-MS), and thermal desorption aerosol GC-MS (TAG). Previously identified as a potential bark beetle disruptant, methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO), a light and temperature dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4-68 % of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72-10.2 μ gCg-1h-1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde) in the ambient atmosphere. Methyl chavicol is a major essential oil component of many species. We propose this newly- characterized biogenic compound should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  7. Influence of headspace pressure on methane production in Biochemical Methane Potential (BMP) tests.

    PubMed

    Valero, David; Montes, Jesús A; Rico, José Luis; Rico, Carlos

    2016-02-01

    The biochemical methane potential test is the most commonly applied method to determine methane production from organic wastes. One of the parameters measured is the volume of biogas produced which can be determined manometrically by keeping the volume constant and measuring increases in pressure. In the present study, the effect of pressure accumulation in the headspace of the reactors has been studied. Triplicate batch trials employing cocoa shell, waste coffee grounds and dairy manure as substrates have been performed under two headspace pressure conditions. The results obtained in the study showed that headspace overpressures higher than 600mbar affected methane production for waste coffee grounds. On the contrary, headspace overpressures within a range of 600-1000mbar did not affect methane production for cocoa shell and dairy manure. With the analyses performed in the present work it has not been possible to determine the reasons for the lower methane yield value obtained for the waste coffee grounds under high headspace pressures.

  8. Secondary Organic Aerosol Formation by Molecular-Weight Building Reactions of Biogenic Oxidation Products

    NASA Astrophysics Data System (ADS)

    Barsanti, K.; Guenther, A.; Matsunaga, S.; Smith, J.

    2006-12-01

    Understanding the chemical composition of atmospheric organic aerosols (OA) remains one of the significant challenges to accurately representing OA in air quality and climate models. Meeting this challenge will require further understanding of secondary organic aerosols (SOA), of which biogenic emissions are thought to be major precursors. Of recent interest is the significance of higher-molecular weight (MW) compounds (i.e., "oligomers"). Theoretical, laboratory, and field study results suggest that relatively volatile oxidation products may contribute to SOA formation through multi-phase MW- building reactions. The significance of such reactions for biogenic SOA formation, including for newly considered precursors such as isoprene, is explored in this work. Theoretical and field studies are employed to: 1) identify MW-building reactions that may contribute to SOA formation in the atmosphere, 2) identify MW-building reaction products in ambient samples, and 3) parameterize atmospheric SOA formation by MW-building reactions of biogenic oxidation products. Likely reactions of biogenic oxidation products include ester, amide, and peroxyhemiacetal formation. Each of the proposed reactions involves known oxidation productions of biogenic precursors (e.g., carboxylic acids and aldehydes) reacting with one another and/or other atmospheric constituents (e.g., sulfuric acid and ammonia) to form higher-MW/lower-volatility products that can condense to form SOA. It has been suggested that products of MW-building reactions can revert to the parent reactants during sampling and analysis. Thus, relatively volatile compounds detected in ambient particle samples in fact may be decomposition products of higher-MW products. The contribution of relatively volatile biogenic oxidation products to SOA via ester, amide, and peroxyhemiacetal formation, as determined by studies based on fundamental thermodynamics and gas/particle partitioning theory, will be discussed; in addition to

  9. Development of Sand Production Evaluation Apparatus for Methane Hydrate Development

    NASA Astrophysics Data System (ADS)

    Kakumoto, M.; Yoneda, J.; Tenma, N.; Katagiri, J.; Noda, S.

    2015-12-01

    As a part of a Japanese National hydrate research program (MH21, funded by METI), we performed a study on sand production mechanism during methane gas production. In 2013, the first methane hydrate offshore production test was conducted in Japan, and it was recognized in the production of about 20000m3/day of methane gas from methane hydrate bearing sand sediment in deep marine sediment. In methane hydrate development, depressurization method has been proposed for gas extraction. This method is a method to reduce the bottom hole pressure by submersible pump lowering water level in the production well, and gas and water is recovered by methane hydrate dissociation at the in situ. At that time, a phenomenon that sand flows into the wells is feared. In actually, sand production phenomenon occurred after 6 days from production start in offshore production test. A mechanism of sand production has not yet been resolved in case of methane hydrate development. Therefore, we developed large scale laboratory test apparatus for the purpose of elucidation of the mechanism of sand production phenomenon. In this presentation, we introduce basic performance of this apparatus, and usefulness is made mention by representative test results.

  10. Ecosystem and physiological controls over methane production in northern wetlands

    SciTech Connect

    Valentine, D.W.; Holland, E.A.; Schimel, D.S.

    1994-01-20

    Peat chemistry appears to exert primary control over methane production rates in the Canadian Northern Wetlands Study (NOWES) area. We determined laboratory methane production rate potentials in anaerobic slurries of samples collected from a transect of sites through the NOWES study area. We related methane production rates to indicators of resistance to microbial decay (peat C:N and lignin:N ratios) and experimentally manipulated substrate availability for methanogenesis using ethanol (EtOH) and plant litter. We also determined responses of methane production to pH and temperature. Methane production potentials declined along the gradient of sites from high rates in the coastal fens to low rates in the interior bogs and were generally highest in surface layers. Strong relationships between CH{sub 4} production potentials and peat chemistry suggested that methanogenesis was limited by fermentation rates. Methane production at ambient pH responded strongly to substrate additions in the circumneutral fens with narrow lignin:N and C:N ratios ({partial_derivative}CH{sub 4}/{partial_derivative}EtOH = 0.9-2.3 mg g{sup {minus}1}) and weakly in the acidic bogs with wide C:N and lignin:N ratios ({partial_derivative}CH{sub 4}/{partial_derivative}EtOH = -0.4-0.02 mg g{sup {minus}1}). Observed Q{sub 10} values ranged from 1.7 to 4.7 and generally increased with increasing substrate availability, suggesting that fermentation rates were limiting. Titration experiments generally demonstrated inhibition of methanogenesis by low pH. Our results suggest that the low rates of methane emission observed in interior bogs during NOWES likely resulted from pH and substrate quality limitation of the fermentation step in methane production and thus reflect intrinsically low methane production potentials. Low methane emission rates observed during NOWES will likely be observed in other northern wetland regions with similar vegetation chemistry. 57 refs., 5 figs., 4 tabs.

  11. Ecosystem and physiological controls over methane production in northern wetlands

    NASA Technical Reports Server (NTRS)

    Valentine, David W.; Holland, Elisabeth A.; Schimel, David S.

    1994-01-01

    Peat chemistry appears to exert primary control over methane production rates in the Canadian Northern Wetlands Study (NOWES) area. We determined laboratory methane production rate potentials in anaerobic slurries of samples collected from a transect of sites through the NOWES study area. We related methane production rates to indicators of resistance to microbial decay (peat C: N and lignin: N ratios) and experimentally manipulated substrate availability for methanogenesis using ethanol (EtOH) and plant litter. We also determined responses of methane production to pH and temperature. Methane production potentials declined along the gradient of sites from high rates in the coastal fens to low rates in the interior bogs and were generally highest in surface layers. Strong relationships between CH4 production potentials and peat chemistry suggested that methanogenesis was limited by fermentation rates. Methane production at ambient pH responded strongly to substrate additions in the circumneutral fens with narrow lignin: N and C: N ratios (delta CH4/delta EtOH = 0.9-2.3 mg/g) and weakly in the acidic bogs with wide C: N and lignin: N ratios (delta CH4/delta EtOH = -0.04-0.02 mg/g). Observed Q(sub 10) values ranged from 1.7 to 4.7 and generally increased with increasing substrate availability, suggesting that fermentation rates were limiting. Titration experiments generally demonstrated inhibition of methanogenesis by low pH. Our results suggest that the low rates of methane emission observed in interior bogs during NOWES likely resulted from pH and substrate quality limitation of the fermentation step in methane production and thus reflect intrinsically low methane production potentials. Low methane emission rates observed during NOWES will likely be observed in other northern wetland regions with similar vegetation chemistry.

  12. Transcriptomic evidence for net methane oxidation and net methane production in putative ANaerobic MEthanotrophic (ANME) archaea

    NASA Astrophysics Data System (ADS)

    Lloyd, K. G.; Alperin, M. J.; Teske, A.

    2010-12-01

    Anaerobic methane oxidation regulates methane emissions in marine sediments and is thought to be mediated by uncultured methanogen-like archaea collectively labeled ANME (for ANaerobic MEthanotrophs). ANME archaea are often assumed to be obligate methanotrophs that are incapable of net methanogenesis, and are therefore used as proxies for anaerobic methane oxidation in many environments in spite of uncertainty regarding their metabolic capabilities. We tested this assumption by detecting and quantifying methanogenic gene transcription of ANME archaea across clearly differentiated zones of methane oxidation vs. methane production in sediments from the White Oak River estuary, NC. ANME-1 archaea (a group of putative obligate methanotrophs) consistently transcribe 16S rRNA and mRNA of methyl coenzyme M reductase (mcrA) the key gene for methanogenesis, up to 45 cm into methanogenic sediments. CARD-FISH shows that ANME-1 archaea exist as single rod-shaped cells or pairs of cells, and in very low numbers. Integrating normalized depth-distributions of 16S rDNA and rRNA (measured with qPCR and RT-qPCR, respectively) shows that 26-77 % of the rDNA proxy for ANME-1 cell numbers, and 18-74 % of the rRNA proxy for ANME-1 activity occurs within methane-producing sediments. mRNA transcripts of dissimilatory sulfite reductase (dsrAB) from sulfate reducing bacteria, the putative syntrophic partners of sulfate-dependent methane oxidation, were amplified consistently from methane-oxidizing sediments, and inconsistently from methane-producing sediments. These results change the perspective from ANME-1 archaea as obligate methane oxidizers to methanogens that are also capable of methane oxidation.

  13. Detection and quantification of biogenic amines in fermented food products sold in Botswana.

    PubMed

    Magwamba, Clement; Matsheka, Maitshwarelo Ignatius; Mpuchane, Sisai; Gashe, Berhanu Abegaz

    2010-09-01

    The incidence and concentrations associated with four important biogenic amines in leading commercial fermented beverages consumed in Botswana were determined using high-performance liquid chromatography. In 87 sorghum brew and 84 sour milk (madila, amasi) samples tested, putrescine was the most prevalent biogenic amine (63 and 61%, respectively), while histamine was the least prevalent (24 and 8%, respectively). Cadaverine was the most frequently detected biogenic amine in 79 of the commercial sour maize beverage (mageu/mahewu) samples tested (found in 70% of the samples), while tyramine was the least detected (occurring in 3% of the samples). In sorghum brew and sour milk, tyramine was found to be the most concentrated (mean concentration of 2.08 mg/100 ml and 3.2 mg/100 ml, respectively), and histamine was found to be the least concentrated (mean concentration of 0.94 mg/100 ml and 0.31 mg/100 ml, respectively). Overall, the biogenic amine concentrations of all three fermented products were within acceptable limits. However, one sorghum brew sample had a histamine content of 5.8 mg/ 100 ml, which was above the 5.0 mg/100 g allowable limit suggested by the U.S. Food and Drug Administration.

  14. Biogenic tellurium nanorods as a novel antivirulence agent inhibiting pyoverdine production in Pseudomonas aeruginosa.

    PubMed

    Mohanty, Anee; Kathawala, Mustafa Hussain; Zhang, Jianhua; Chen, Wei Ning; Loo, Joachim Say Chye; Kjelleberg, Staffan; Yang, Liang; Cao, Bin

    2014-05-01

    While antibiotic resistance in bacteria is rapidly increasing, the development of new antibiotics has decreased in recent years. Antivirulence drugs disarming rather than killing pathogens have been proposed to alleviate the problem of resistance inherent to existing biocidal antibiotics. Here, we report a nontoxic biogenic nanomaterial as a novel antivirulence agent to combat bacterial infections caused by Pseudomonas aeruginosa. We synthesized, in an environmentally benign fashion, tellurium nanorods (TeNRs) using the metal-reducing bacterium Shewanella oneidensis, and found that the biogenic TeNRs could effectively inhibit the production of pyoverdine, one of the most important virulence factors in P. aeruginosa. Our results suggest that amyloids and extracellular polysaccharides Pel and Psl are not involved in the interactions between P. aeruginosa and the biogenic TeNRs, while flagellar movement plays an important role in the cell-TeNRs interaction. We further showed that the TeNRs (up to 100 µg/mL) did not exhibit cytotoxicity to human bronchial epithelial cells and murine macrophages. Thus, biogenic TeNRs hold promise as a novel antivirulence agent against P. aeruginosa.

  15. Methane production from grape skins. Final technical report

    SciTech Connect

    Yunghans, W.N.

    1981-10-09

    Methane production from grape pomace was measured for a 50-day digestion period. Gas production was calculated to be 2400 ft/sup 3//10 d/ton at 53% methane content. Microorganisms particularly a fungus which grows on grape pomace and lignin was isolated. Lignin content of pomace was measured at approximately 60%. Lignin is slowly digested and may represent a residue which requires long term digestion. Research is continuing on isolation of anaerobic methane bacteria and codigestion of pomace with enzymes as cellulase and pectinase. The sewage sludge functioned adequately as a mixed source of organisms capable of digesting grape pomace. A sediment from stored grape juice produced significant amounts of methane and represents a nutrient substrate for additional studies on continuous flow methane production. 3 figs.

  16. Relationship between selection for feed efficiency and methane production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enteric methane is a product of fermentation in the gastro-intestinal tract of ruminants. A group of archaea bacteria collectively called “methanogens” are responsible for the synthesis of methane. In ruminants, the methanogens grow in the reticulum-rumen complex and in the cecum. Most of the met...

  17. Effect of Soybean Meal and Soluble Starch on Biogenic Amine Production and Microbial Diversity Using In vitro Rumen Fermentation.

    PubMed

    Jeong, Chang-Dae; Mamuad, Lovelia L; Kim, Seon-Ho; Choi, Yeon Jae; Soriano, Alvin P; Cho, Kwang Keun; Jeon, Che-Ok; Lee, Sung Sil; Lee, Sang-Suk

    2015-01-01

    This study was conducted to investigate the effect of soybean meal (SM) and soluble starch (SS) on biogenic amine production and microbial diversity using in vitro ruminal fermentation. Treatments comprised of incubation of 2 g of mixture (expressed as 10 parts) containing different ratios of SM to SS as: 0:0, 10:0, 7:3, 5:5, 3:7, or 0:10. In vitro ruminal fermentation parameters were determined at 0, 12, 24, and 48 h of incubation while the biogenic amine and microbial diversity were determined at 48 h of incubation. Treatment with highest proportion of SM had higher (p<0.05) gas production than those with higher proportions of SS. Samples with higher proportion of SS resulted in lower pH than those with higher proportion of SM after 48 h of incubation. The largest change in NH3-N concentration from 0 to 48 h was observed on all SM while the smallest was observed on exclusive SS. Similarly, exclusive SS had the lowest NH3-N concentration among all groups after 24 h of incubation. Increasing methane (CH4) concentrations were observed with time, and CH4 concentrations were higher (p<0.05) with greater proportions of SM than SS. Balanced proportion of SM and SS had the highest (p<0.05) total volatile fatty acid (TVFA) while propionate was found highest in higher proportion of SS. Moreover, biogenic amine (BA) was higher (p<0.05) in samples containing greater proportions of SM. Histamines, amine index and total amines were highest in exclusive SM followed in sequence mixtures with increasing proportion of SS (and lowered proportion of SM) at 48 h of incubation. Nine dominant bands were identified by denaturing gradient gel electrophoresis (DGGE) and their identity ranged from 87% to 100% which were mostly isolated from rumen and feces. Bands R2 (uncultured bacterium clone RB-5E1) and R4 (uncultured rumen bacterium clone L7A_C10) bands were found in samples with higher proportions of SM while R3 (uncultured Firmicutes bacterium clone NI_52), R7 (Selenomonas sp. MCB2

  18. Forest cockchafer larvae as methane production hotspots in soils and their importance for net soil methane fluxes

    NASA Astrophysics Data System (ADS)

    Görres, Carolyn-Monika; Kammann, Claudia; Murphy, Paul; Müller, Christoph

    2016-04-01

    Certain groups of soil invertebrates, namely scarab beetles and millipedes, are capable of emitting considerable amounts of methane due to methanogens inhabiting their gut system. It was already pointed out in the early 1990's, that these groups of invertebrates may represent a globally important source of methane. However, apart from termites, the importance of invertebrates for the soil methane budget is still unknown. Here, we present preliminary results of a laboratory soil incubation experiment elucidating the influence of forest cockchafer larvae (Melolontha hippocastani FABRICIUS) on soil methane cycling. In January/February 2016, two soils from two different management systems - one from a pine forest (extensive use) and one from a vegetable field (intensive use) - were incubated for 56 days either with or without beetle larvae. Net soil methane fluxes and larvae methane emissions together with their stable carbon isotope signatures were quantified at regular intervals to estimate gross methane production and gross methane oxidation in the soils. The results of this experiment will contribute to testing the hypothesis of whether methane production hotspots can significantly enhance the methane oxidation capacity of soils. Forest cockchafer larvae are only found in well-aerated sandy soils where one would usually not suspect relevant gross methane production. Thus, besides quantifying their contribution to net soil methane fluxes, they are also ideal organisms to study the effect of methane production hotspots on overall soil methane cycling. Funding support: Reintegration grant of the German Academic Exchange Service (DAAD) (#57185798).

  19. High-pressure anaerobic digestion up to 100 bar: influence of initial pressure on production kinetics and specific methane yields.

    PubMed

    Merkle, Wolfgang; Baer, Katharina; Haag, Nicola Leonard; Zielonka, Simon; Ortloff, Felix; Graf, Frank; Lemmer, Andreas

    2017-02-01

    To ensure an efficient use of biogas produced by anaerobic digestion, in some cases it would be advisable to upgrade the biogenic gases and inject them into the transnational gas grids. To investigate biogas production under high-pressure conditions up to 100 bar, new pressure batch methane reactors were developed for preliminary lab-scale experiments with a mixture of grass and maize silage hydrolysate. During this investigation, the effects of different initial pressures (1, 50 and 100 bar) on pressure increase, gas production and the specific methane yield using nitrogen as inert gas were determined. Based on the experimental findings increasing initial pressures alter neither significantly, further pressure increases nor pressure increase rates. All supplied organic acids were degraded and no measurable inhibition of the microorganisms was observed. The results show that methane reactors can be operated at operating pressures up to 100 bar without any negative effects on methane production.

  20. Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications

    SciTech Connect

    Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto; Kerminen, Veli-Matti; Junninen, Heikki; Paasonen, Pauli; Stratmann, Frank; Herrmann, Hartmut; Guenther, Alex B.; Worsnop, Douglas R.; Kulmala, M.; Ehn, Mikael K.; Sipila, Mikko

    2015-06-09

    Extremely low volatility organic compounds (ELVOC) are suggested to promote aerosol particle formation and cloud condensation nuclei (CCN) production in the atmosphere. We show that the capability of biogenic VOC (BVOC) to produce ELVOC depends strongly on their chemical structure and relative oxidant levels. BVOC with an endocyclic double bond, representative emissions from, e.g., boreal forests, efficiently produce ELVOC from ozonolysis. Compounds with exocyclic double bonds or acyclic compounds including isoprene, emission representative of the tropics, produce minor quantities of ELVOC, and the role of OH radical oxidation is relatively larger. Implementing these findings into a global modeling framework shows that detailed assessment of ELVOC production pathways is crucial for understanding biogenic secondary organic aerosol and atmospheric CCN formation.

  1. Influence of headspace flushing on methane production in Biochemical Methane Potential (BMP) tests.

    PubMed

    Koch, Konrad; Fernández, Yadira Bajón; Drewes, Jörg E

    2015-06-01

    The influence of headspace flushing on the specific methane (CH4) production of blank samples with just inoculum in Biochemical Methane Potential (BMP) tests was studied. The three most common ways were applied: flushing with nitrogen (N2) gas, flushing with a mixture of N2 and CO2 (80/20 v/v), and no flushing. The results revealed that removing the oxygen is crucial to avoid aerobic respiration, which caused both hindered activity of methanogens and loss of methane potential. Furthermore it was demonstrated that 20% of CO2 in the flush gas increased significantly the methane production by over 20% compared to the flushing with pure N2. In order to mimic the same headspace conditions as in full-scale treatment plants, using a flush gas with a similar CO2 concentration as the expected biogas is suggested.

  2. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Donn McGuire; Thomas Williams; Bjorn Paulsson; Alexander Goertz

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a drilling hazard by the oil and gas industry for years. Drilling engineers working in Russia, Canada and the USA have documented numerous problems, including drilling kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrates as a potential energy source agree that the resource potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained from physical samples taken from actual hydrate-bearing rocks. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The project team drilled and continuously cored the Hot Ice No. 1 well on Anadarko-leased acreage beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and used for determining physical characteristics of hydrates and surrounding rock. After the well was logged, a 3D vertical seismic profile (VSP) was recorded to calibrate the shallow geologic section with seismic data and to investigate techniques to better resolve lateral subsurface variations of potential hydrate-bearing strata. Paulsson Geophysical Services, Inc. deployed their 80 level 3C clamped borehole seismic receiver array in the wellbore to record samples every 25 ft. Seismic vibrators were successively positioned at 1185 different surface positions in a circular pattern around the wellbore. This technique generated a 3D image of the subsurface. Correlations were

  3. PEaCH4 v.2.0: A modelling platform to predict early diagenetic processes in marine sediments with a focus on biogenic methane - Case study: Offshore Namibia

    NASA Astrophysics Data System (ADS)

    Arning, Esther T.; Häußler, Steffen; van Berk, Wolfgang; Schulz, Hans-Martin

    2016-07-01

    The modelling of early diagenetic processes in marine sediments is of interest in marine science, and in the oil and gas industry, here, especially with respect to methane occurrence and gas hydrate formation as resources. Early diagenesis in marine sediments evolves from a complex web of intertwining (bio)geochemical reactions. It comprises microbially catalysed reactions and inorganic mineral-water-gas interactions. A model that will describe and consider all of these reactions has to be complex. However, it should be user-friendly, as well as to be applicable for a broad community and not only for experts in the field of marine chemistry. The presented modelling platform PeaCH4 v.2.0 combines both aspects, and is Microsoft Excel©-based. The modelling tool is PHREEQC (version 2), a computer programme for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations. The conceptual PEaCH4 model is based on the conversion of sediment-bound degradable organic matter. PEaCH4 v.2.0 was developed to quantify and predict early diagenetic processes in marine sediments with the focus on biogenic methane formation and its phase behaviour, and allows carbon mass balancing. In regard to the irreversible degradation of organic matter, it comprises a "reaction model" and a "kinetic model" to predict methane formation. Both approaches differ in their calculations and outputs as the "kinetic model" considers the modelling time to integrate temperature dependent biogenic methane formation in its calculations, whereas the "reaction model" simply relies on default organic matter degradation. With regard to the inorganic mineral-water-gas interactions, which are triggered by irreversible degradation of organic matter, PEaCH4 v.2.0 is based on chemical equilibrium thermodynamics, appropriate mass-action laws, and their temperature dependent equilibrium constants. The programme is exemplarily presented with the example of upwelling sediments off Namibia

  4. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Bill Liddell

    2005-03-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Oil-field engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in Arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrates agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to help identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. As part of the project work scope, team members drilled and cored the HOT ICE No. 1 on Anadarko leases beginning in January 2003 and completed in March 2004. Due to scheduling constraints imposed by the Arctic drilling season, operations at the site were suspended between April 21, 2003 and January 30, 2004. An on-site core analysis laboratory was designed, constructed and used for determining physical characteristics of frozen core immediately after it was retrieved from the well. The well was drilled from a new and innovative Anadarko Arctic Platform that has a greatly reduced footprint and environmental impact. Final efforts of the project were to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists for future hydrate operations. Unfortunately, no gas hydrates were encountered in this well; however, a wealth of information was generated and is

  5. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Buddy King

    2004-06-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope drilled and cored a well The HOT ICE No.1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report.

  6. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Buddy King

    2004-07-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope drilled and cored a well The HOT ICE No.1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report.

  7. Comparing Siliceous Productivity Proxies Along the California Margin During Pliocene Warmth: Smear Slides vs. Biogenic Silica

    NASA Astrophysics Data System (ADS)

    Schwartz, V.; Dekens, P. S.; Addison, J. A.

    2015-12-01

    The early Pliocene (5.3-2.6 Ma) is the most recent time in Earth history when CO2 levels were similar to today, yet model outputs show average global atmospheric temperatures were 3-4˚C warmer. Given the similar climate boundary conditions in the Pliocene and today (CO2, continental positions, ocean circulation), the Pliocene is the best analogue for future climate in the paleo-record. Proxy studies reveal Pliocene sea surface temperatures (SST) along the California margin were 3-9˚C warmer than today. The modern California margin is highly productive, driven by strong seasonal upwelling of cold, nutrient-rich water. If the thermocline and nutricline were coupled during the Pliocene as they are today, warmer SSTs would imply lower nutrient concentrations and reduced productivity. Yet previously published oceanic records do not show a clear relationship between SST and productivity. Alkenone mass accumulation rates (MAR), organic carbon, and biogenic silica show sustained levels of productivity in the Pliocene even as SST was cooling at ODP Site 1022 (40.0˚N, 125.5˚W, depth 1925 m). However, smear slide analysis suggests that diatom MAR decreased during the Pliocene. Because diatoms are the dominant silica-based primary producer, diatom MAR and biogenic silica analyses should display similar variations. The apparent difference between the two proxy records may be due to preservational effects, such as silica dissolution in the sedimentary pore waters and fragmentation of diatom frustules, resulting in reduced diatom MARs, whereas the fragments and non-diatom siliceous producers all contribute to the biogenic silica values. We present smear slide and biogenic silica analyses as records of diatom productivity at the more southerly ODP Site 1016 (34.0˚N, 122.0˚W, depth 3835 m), and compare it to existing data from ODP Site 1022. In the modern ocean, diatoms dominate California margin phytoplankton under high nutrient upwelling conditions; thus changes in the

  8. On baseline determination and gas saturation derivation from downhole electrical monitoring of shallow biogenic gas production

    NASA Astrophysics Data System (ADS)

    Pezard, P. A.; Celerier, B. P.

    2015-12-01

    Adequate hydrogeophysical monitoring of CO2 geological storage remains a challenge as different parameters might be modified during storage. That implies to compare real-time measurements to an adequate baseline. At the Maguelone shallow experimental site a representative baseline for electrical resistivity was built from a large number of downhole geophysical measurements recorded over time. At this coastal site this issue is particularly important due to the production of biogenic gas at shallow depth (< 200 m) from the subsurface sediments.For this, a modified petrophysical model based on the Waxman-Smits model is proposed to estimate gas saturation found to vary up to 7% within shallow sand layers, indicating that natural gas production within the sedimentary pile from biological activity cannot be neglected during gas injection experiments. In the two main reservoirs located at shallow depth (R1 and R2), a variable gas content of 7% and 4% was obtained over short periods of time in the TLL6 and DSO1 boreholes, respectively. The difference might be due to the gentle stratigraphic slope identified from cross hole log and core analyses, TLL6 being located upslope from DSO1. This study also revealed a rapid dynamic mechanism resulting in transfer of biogenic gas from the bottom reservoir (R1) to the top one (R2), possibly due to gas leaking along some of the monitoring boreholes. These sand-rich layers constitute buffer reservoirs for biogenic gases before being released to the atmosphere. Future studies at Maguelone will first focus on biogenic gas sampling from a downhole multi-packer completion in order to identify and quantify the different gas phases produced over time by the sedimentary pile.

  9. Molecular and isotopic signatures in sediments and gas hydrate of the central/southwestern Ulleung Basin: high alkalinity escape fuelled by biogenically sourced methane

    NASA Astrophysics Data System (ADS)

    Kim, Ji-Hoon; Park, Myong-Ho; Chun, Jong-Hwa; Lee, Joo Yong

    2011-02-01

    -bound gases, and helps clarify some contradictory interpretations existing for the Ulleung Basin as a whole. In combination, these findings suggest that deep biogenic gas and pore waters migrate upward through pathways such as hydrofractures, and measurably influence the shallow carbon cycle. As a result, cation-adjusted alkalinity/removed sulfate diagrams cannot always serve to estimate the degree of alkalinity produced by sulfate reduction and AOM in high methane flux areas.

  10. 800-year ice-core record of nitrogen deposition in Svalbard linked to ocean productivity and biogenic emissions

    NASA Astrophysics Data System (ADS)

    Wendl, I. A.; Eichler, A.; Isaksson, E.; Martma, T.; Schwikowski, M.

    2015-07-01

    We present the records of the two nitrogen species nitrate (NO3-) and ammonium (NH4+) analysed in a new ice core from Lomonosovfonna, Svalbard, in the Eurasian Arctic covering the period 1222-2009. Changes in melt at the Lomonosovfonna glacier are assumed to have a negligible effect on the decadal variations of the investigated compounds. Accordingly, we use decadal records to investigate the major emission sources of NO3- and NH4+ precursors and find that during the twentieth century both records are influenced by anthropogenic pollution from Eurasia. In pre-industrial times NO3- is highly correlated with methane sulfonate (MSA), which we explain by a fertilising effect. We propose that enhanced atmospheric NO3- concentrations and the corresponding nitrogen input to the ocean trigger the growth of dimethyl-sulfide-(DMS)-producing phytoplankton. Increased DMS production results in elevated fluxes to the atmosphere where it is oxidised to MSA. Eurasia was presumably the main source area also of pre-industrial NO3-, but a more exact source apportionment could not be performed based on our data. This is different for NH4+, where biogenic ammonia (NH3) emissions from Siberian boreal forests were identified as the dominant source of pre-industrial NH4+.

  11. Using stable isotopes of hydrogen to quantify biogenic and thermogenic atmospheric methane sources: A case study from the Colorado Front Range

    NASA Astrophysics Data System (ADS)

    Townsend-Small, Amy; Botner, E. Claire; Jimenez, Kristine L.; Schroeder, Jason R.; Blake, Nicola J.; Meinardi, Simone; Blake, Donald R.; Sive, Barkley C.; Bon, Daniel; Crawford, James H.; Pfister, Gabriele; Flocke, Frank M.

    2016-11-01

    Global atmospheric concentrations of methane (CH4), a powerful greenhouse gas, are increasing, but because there are many natural and anthropogenic sources of CH4, it is difficult to assess which sources may be increasing in magnitude. Here we present a data set of δ2H-CH4 measurements of individual sources and air in the Colorado Front Range, USA. We show that δ2H-CH4, but not δ13C, signatures are consistent in air sampled downwind of landfills, cattle feedlots, and oil and gas wells in the region. Applying these source signatures to air in ground and aircraft samples indicates that at least 50% of CH4 emitted in the region is biogenic, perhaps because regulatory restrictions on leaking oil and natural gas wells are helping to reduce this source of CH4. Source apportionment tracers such as δ2H may help close the gap between CH4 observations and inventories, which may underestimate biogenic as well as thermogenic sources.

  12. Detection and Production of Methane Hydrate

    SciTech Connect

    George Hirasaki; Walter Chapman; Gerald Dickens; Colin Zelt; Brandon Dugan; Kishore Mohanty; Priyank Jaiswal

    2011-12-31

    This project seeks to understand regional differences in gas hydrate systems from the perspective of as an energy resource, geohazard, and long-term climate influence. Specifically, the effort will: (1) collect data and conceptual models that targets causes of gas hydrate variance, (2) construct numerical models that explain and predict regional-scale gas hydrate differences in 2-dimensions with minimal 'free parameters', (3) simulate hydrocarbon production from various gas hydrate systems to establish promising resource characteristics, (4) perturb different gas hydrate systems to assess potential impacts of hot fluids on seafloor stability and well stability, and (5) develop geophysical approaches that enable remote quantification of gas hydrate heterogeneities so that they can be characterized with minimal costly drilling. Our integrated program takes advantage of the fact that we have a close working team comprised of experts in distinct disciplines. The expected outcomes of this project are improved exploration and production technology for production of natural gas from methane hydrates and improved safety through understanding of seafloor and well bore stability in the presence of hydrates. The scope of this project was to more fully characterize, understand, and appreciate fundamental differences in the amount and distribution of gas hydrate and how this would affect the production potential of a hydrate accumulation in the marine environment. The effort combines existing information from locations in the ocean that are dominated by low permeability sediments with small amounts of high permeability sediments, one permafrost location where extensive hydrates exist in reservoir quality rocks and other locations deemed by mutual agreement of DOE and Rice to be appropriate. The initial ocean locations were Blake Ridge, Hydrate Ridge, Peru Margin and GOM. The permafrost location was Mallik. Although the ultimate goal of the project was to understand processes

  13. Methane production from global biomass burning

    SciTech Connect

    Wei Min Hao; Ward, D.E.

    1993-11-20

    Emissions of methane from various sources of biomass burning are determined quantitatively for tropical, temperate, and boreal regions. About 85% of the total CH{sub 4} is emitted in the tropical area, which is mainly the result of shifting cultivation, fuelwood use, and deforestation. Methane emissions from biomass burning may have increased by at least 9% during the last decade because of increases in tropical deforestation and the use of fuelwood. Changes in land use practices and population growth in the tropics are possible causes of the increase of atmospheric CH{sub 4} concentration. 31 refs., 1 fig., 4 tabs.

  14. Energy from anaerobic methane production. [Sweden

    SciTech Connect

    Not Available

    1982-02-01

    Since 1970 Swedish researchers have been testing the ANAMET (anaerobic-aerobic-methane) process, which involves converting industrial wastewaters via an initial anaerobic microbiological step followed by an aerobic one. Recycling the biomass material in each step allows shorter hydraulic retention times without decreasing stability or solids reduction. Since the first ANAMET plants began operating at a Swedish sugar factory in 1972, 17 more plants have started up or are under construction. Moreover, the ANAMET process has engendered to offshoot BIOMET (biomass-methane) process, a thermophilic anaerobic scheme that can handle sugar-beet pulp as well as grass and other soft, fast-growing biomasses.

  15. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Richard Sigal; Kent Newsham; Thomas Williams; Barry Freifeld; Timothy Kneafsey; Carl Sondergeld; Shandra Rai; Jonathan Kwan; Stephen Kirby; Robert Kleinberg; Doug Griffin

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. The work scope drilled and cored a well The Hot Ice No. 1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report. The Hot Ice No. 1 well was drilled from the surface to a measured depth of 2300 ft. There was almost 100% core recovery from the bottom of surface casing at 107 ft to total depth. Based on the best estimate of the bottom of the methane hydrate stability zone (which used new data obtained from Hot Ice No. 1 and new analysis of data from adjacent wells), core was recovered over its complete range. Approximately 580 ft of porous, mostly frozen, sandstone and 155 of conglomerate were recovered in the Ugnu Formation and approximately 215 ft of porous sandstone were recovered in the West Sak Formation. There were gas shows in the bottom

  16. Methane production from acid hydrolysates of Agave tequilana bagasse: evaluation of hydrolysis conditions and methane yield.

    PubMed

    Arreola-Vargas, Jorge; Ojeda-Castillo, Valeria; Snell-Castro, Raúl; Corona-González, Rosa Isela; Alatriste-Mondragón, Felipe; Méndez-Acosta, Hugo O

    2015-04-01

    Evaluation of diluted acid hydrolysis for sugar extraction from cooked and uncooked Agave tequilana bagasse and feasibility of using the hydrolysates as substrate for methane production, with and without nutrient addition, in anaerobic sequencing batch reactors (AnSBR) were studied. Results showed that the hydrolysis over the cooked bagasse was more effective for sugar extraction at the studied conditions. Total sugars concentration in the cooked and uncooked bagasse hydrolysates were 27.9 g/L and 18.7 g/L, respectively. However, 5-hydroxymethylfurfural was detected in the cooked bagasse hydrolysate, and therefore, the uncooked bagasse hydrolysate was selected as substrate for methane production. Interestingly, results showed that the AnSBR operated without nutrient addition obtained a constant methane production (0.26 L CH4/g COD), whereas the AnSBR operated with nutrient addition presented a gradual methane suppression. Molecular analyses suggested that methane suppression in the experiment with nutrient addition was due to a negative effect over the archaeal/bacterial ratio.

  17. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Steve Runyon; Mike Globe; Kent Newsham; Robert Kleinberg; Doug Griffin

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project was a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope included drilling and coring a well (Hot Ice No. 1) on Anadarko leases beginning in FY 2003 and completed in 2004. During the first drilling season, operations were conducted at the site between January 28, 2003 to April 30, 2003. The well was spudded and drilled to a depth of 1403 ft. Due to the onset of warmer weather, work was then suspended for the season. Operations at the site were continued after the tundra was re-opened the following season. Between January 12, 2004 and March 19, 2004, the well was drilled and cored to a final depth of 2300 ft. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and

  18. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Bill Liddell

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to help identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. As part of the project work scope, team members drilled and cored a well (the Hot Ice No. 1) on Anadarko leases beginning in January 2003 and completed in March 2004. Due to scheduling constraints imposed by the Arctic drilling season, operations at the site were suspended between April 21, 2003 and January 30, 2004. An on-site core analysis laboratory was constructed and used for determining physical characteristics of frozen core immediately after it was retrieved from the well. The well was drilled from a new and innovative Anadarko Arctic Platform that has a greatly reduced footprint and environmental impact. Final efforts of the project were to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists for future hydrate operations. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in the

  19. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Ali Kadaster; Bill Liddell; Tommy Thompson; Thomas Williams; Michael Niedermayr

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project was a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope included drilling and coring a well (Hot Ice No. 1) on Anadarko leases beginning in FY 2003 and completed in 2004. During the first drilling season, operations were conducted at the site between January 28, 2003 to April 30, 2003. The well was spudded and drilled to a depth of 1403 ft. Due to the onset of warmer weather, work was then suspended for the season. Operations at the site were continued after the tundra was re-opened the following season. Between January 12, 2004 and March 19, 2004, the well was drilled and cored to a final depth of 2300 ft. An on-site core analysis laboratory was built and implemented for determining physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. Final efforts of the project are to correlate geology, geophysics, logs, and drilling and

  20. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Bill Liddell

    2004-11-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to help identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. As part of the project work scope, team members drilled and cored a well (the Hot Ice No. 1) on Anadarko leases beginning in January 2003 and completed in March 2004. Due to scheduling constraints imposed by the Arctic drilling season, operations at the site were suspended between April 21, 2003 and January 30, 2004. An on-site core analysis laboratory was constructed and used for determining physical characteristics of frozen core immediately after it was retrieved from the well. The well was drilled from a new and innovative Anadarko Arctic Platform that has a greatly reduced footprint and environmental impact. Final efforts of the project were to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists for future hydrate operations. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in the

  1. Biogenic carbon fluxes from global agricultural production and consumption: Gridded, annual estimates of net ecosystem carbon exchange

    NASA Astrophysics Data System (ADS)

    Wolf, J.; West, T. O.; le Page, Y.; Thomson, A. M.

    2014-12-01

    Quantification of biogenic carbon fluxes from agricultural lands is needed to generate globally consistent bottom-up estimates for carbon monitoring and model input. We quantify agricultural carbon fluxes associated with annual (starting in 1961) crop net primary productivity (NPP), harvested biomass, and human and livestock consumption and emissions, with estimates of uncertainty, by applying region- and species-specific carbon parameters to annual crop, livestock, food and trade inventory data, and generate downscaled, gridded (0.05 degree resolution) representations of these fluxes. In 2011, global crop NPP was 5.25 ± 0.46 Pg carbon (excluding root exudates), of which 2.05 ± 0.051 Pg carbon was harvested as primary crops; an additional 0.54 Pg of crop residue carbon was collected for livestock fodder. In 2011, total livestock feed intake was 2.42 ± 0.21 Pg carbon, of which 2.31 ± 0.21 Pg carbon was emitted as carbon dioxide and 0.072 ± 0.005 Pg carbon was emitted as methane. We estimate that livestock grazed 1.18 Pg carbon from non-crop lands in 2011, representing 48.5 % of global total feed intake. In 2009, the latest available data year, we estimate global human food intake (excluding seafood and orchard fruits and nuts) at 0.52 ± 0.03 Pg carbon, with an additional 0.24 ± 0.01 Pg carbon of food supply chain losses. Trends in production and consumption of agricultural carbon between 1961 and recent years, such as increasing dominance of oilcrops and decreasing percent contribution of pasturage to total livestock feed intake, are discussed, and accounting of all agricultural carbon was done for the years 2005 and 2009. Gridded at 0.05 degree resolution, these quantities represent local uptake and release of agricultural biogenic carbon (e.g. biomass production and removal, residue and manure inputs to soils) and may be used with other gridded data to help estimate current and future changes in soil organic carbon.

  2. Structural control of coalbed methane production in Alabama

    USGS Publications Warehouse

    Pashin, J.C.; Groshong, R.H.

    1998-01-01

    Thin-skinned structures are distributed throughout the Alabama coalbed methane fields, and these structures affect the production of gas and water from coal-bearing strata. Extensional structures in Deerlick Creek and Cedar Cove fields include normal faults and hanging-wall rollovers, and area balancing indicates that these structures are detached in the Pottsville Formation. Compressional folds in Gurnee and Oak Grove fields, by comparison, are interpreted to be detachment folds formed above decollements at different stratigraphic levels. Patterns of gas and water production reflect the structural style of each field and further indicate that folding and faulting have affected the distribution of permeability and the overall success of coalbed methane operations. Area balancing can be an effective way to characterize coalbed methane reservoirs in structurally complex regions because it constrains structural geometry and can be used to determine the distribution of layer-parallel strain. Comparison of calculated requisite strain and borehole expansion data from calliper logs suggests that strain in coalbed methane reservoirs is predictable and can be expressed as fracturing and small-scale faulting. However, refined methodology is needed to analyze heterogeneous strain distributions in discrete bed segments. Understanding temporal variation of production patterns in areas where gas and water production are influenced by map-scale structure will further facilitate effective management of coalbed methane fields.Thin-skinned structures are distributed throughout the Alabama coalbed methane fields, and these structures affect the production of gas and water from coal-bearing strata. Extensional structures in Deerlick Creek and Cedar Cove fields include normal faults and hanging-wall rollovers, and area balancing indicates that these structures are detached in the Pottsville Formation. Compressional folds in Gurnee and Oak Grove fields, by comparison, are interpreted to

  3. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Donn McGuire; Steve Runyon; Richard Sigal; Bill Liddell; Thomas Williams; George Moridis

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. Hot Ice No. 1 was planned to test the Ugnu and West Sak sequences for gas hydrates and a concomitant free gas accumulation on Anadarko's 100% working interest acreage in section 30 of Township 9N, Range 8E of the Harrison Bay quadrangle of the North Slope of Alaska. The Ugnu and West Sak intervals are favorably positioned in the hydrate-stability zone over an area extending from Anadarko's acreage westward to the vicinity of the aforementioned gas-hydrate occurrences. This suggests that a large, north-to-south trending gas-hydrate accumulation may exist in that area. The presence of gas shows in the Ugnu and West Sak reservoirs in wells situated eastward and down dip of the Hot Ice location indicate that a free-gas accumulation may be trapped by gas hydrates. The Hot Ice No. 1 well was designed to core from the surface to the base of the West Sak interval using the revolutionary and new

  4. Topographic Variation and Methane Production in Siberian Arctic Tundra

    NASA Astrophysics Data System (ADS)

    Eason, J.; Kuhn, M. A.; Dunn, S.; Spawn, S.; Schade, J. D.

    2014-12-01

    Understanding the fate of soil carbon when permafrost soils begin to thaw is critical for predicting the impact of permafrost thaw on global climate change. Microbial metabolism of soil carbon can produce carbon dioxide or methane, depending on soil conditions, and which pathway dominates has great significance for the strength of climate feedbacks since methane is a much more powerful greenhouse gas than carbon dioxide. In Arctic ecosystems, methane production from upland environments is not well understood and generally assumed to be low because conditions there are generally not favorable for methanogenesis. Small changes in topography, however, can lead to great heterogeneity in soil conditions at small scales that may lead to higher methane flux than generally recognized. In this study, we investigated patterns in methane, carbon dioxide, and oxygen concentrations in in surface waters of 15 small ponds in the Kolyma River watershed in Northeast Siberia. The ponds were distributed across a topographic gradient from upland tundra high in the landscape to low-lying ponds in the floodplain of the Kolyma River. In addition, we used chambers to measured methane fluxes from a variety of topographic depressions that ranged from pools to moss-dominated saturated soils lacking surface water, to dry soils dominated by sedges. Dissolved carbon dioxide concentrations in ponds showed no trend down the topographic gradient while methane concentrations decreased downslope. The decrease in methane production may be the result of a switch from green moss to brown moss, which may act as a host for methanotrophic bacteria. Ponds with green moss had significantly higher concentrations of methane than the ponds with brown moss. In addition, we found significantly higher methane fluxes from pools and saturated soils then from drier soils, which showed very low fluxes. These results suggest that upland tundra may be a significant source of methane, and that methane fluxes are driven

  5. Potential of biogenic hydrogen production for hydrogen driven remediation strategies in marine environments.

    PubMed

    Hosseinkhani, Baharak; Hennebel, Tom; Boon, Nico

    2014-09-25

    Fermentative production of bio-hydrogen (bio-H2) from organic residues has emerged as a promising alternative for providing the required electron source for hydrogen driven remediation strategies. Unlike the widely used production of H2 by bacteria in fresh water systems, few reports are available regarding the generation of biogenic H2 and optimisation processes in marine systems. The present research aims to optimise the capability of an indigenous marine bacterium for the production of bio-H2 in marine environments and subsequently develop this process for hydrogen driven remediation strategies. Fermentative conversion of organics in marine media to H2 using a marine isolate, Pseudoalteromonas sp. BH11, was determined. A Taguchi design of experimental methodology was employed to evaluate the optimal nutritional composition in batch tests to improve bio-H2 yields. Further optimisation experiments showed that alginate-immobilised bacterial cells were able to produce bio-H2 at the same rate as suspended cells over a period of several weeks. Finally, bio-H2 was used as electron donor to successfully dehalogenate trichloroethylene (TCE) using biogenic palladium nanoparticles as a catalyst. Fermentative production of bio-H2 can be a promising technique for concomitant generation of an electron source for hydrogen driven remediation strategies and treatment of organic residue in marine ecosystems.

  6. Methane Production by Microbial Mats Under Low Sulfate Concentrations

    NASA Technical Reports Server (NTRS)

    Bebout, Brad M.; Hoehler, Tori M.; Thamdrup, Bo; Albert, Dan; Carpenter, Steven P.; Hogan, Mary; Turk, Kendra; DesMarais, David J.

    2003-01-01

    Cyanobacterial mats collected in hypersaline salterns were incubated in a greenhouse under low sulfate concentrations ([SO4]) and examined for their primary productivity and emissions of methane and other major carbon species. Atmospheric greenhouse warming by gases such as carbon dioxide and methane must have been greater during the Archean than today in order to account for a record of moderate to warm paleoclemates, despite a less luminous early sun. It has been suggested that decreased levels of oxygen and sulfate in Archean oceans could have significantly stimulated microbial methanogenesis relative to present marine rates, with a resultant increase in the relative importance of methane in maintaining the early greenhouse. We maintained modern microbial mats, models of ancient coastal marine communities, in artificial brine mixtures containing both modern [SO4=] (ca. 70 mM) and "Archean" [SO4] (less than 0.2 mM). At low [SO4], primary production in the mats was essentially unaffected, while rates of sulfate reduction decreased by a factor of three, and methane fluxes increased by up to ten-fold. However, remineralization by methanogenesis still amounted to less than 0.4 % of the total carbon released by the mats. The relatively low efficiency of conversion of photosynthate to methane is suggested to reflect the particular geometry and chemical microenvironment of hypersaline cyanobacterial mats. Therefore, such mats w-ere probably relatively weak net sources of methane throughout their 3.5 Ga history, even during periods of low- environmental levels oxygen and sulfate.

  7. Diversity of Methane-Oxidizing Bacteria in Soils from “Hot Lands of Medolla” (Italy) Featured by Anomalous High-Temperatures and Biogenic CO2 Emission

    PubMed Central

    Cappelletti, Martina; Ghezzi, Daniele; Zannoni, Davide; Capaccioni, Bruno; Fedi, Stefano

    2016-01-01

    “Terre Calde di Medolla” (TCM) (literally, “Hot Lands of Medolla”) refers to a farming area in Italy with anomalously high temperatures and diffuse emissions of biogenic CO2, which has been linked to CH4 oxidation processes from a depth of 0.7 m to the surface. We herein assessed the composition of the total bacterial community and diversity of methane-oxidizing bacteria (MOB) in soil samples collected at a depth at which the peak temperature was detected (0.6 m). Cultivation-independent methods were used, such as: i) a clone library analysis of the 16S rRNA gene and pmoA (coding for the α-subunit of the particulate methane monooxygenase) gene, and ii) Terminal Restriction Fragment Length Polymorphism (T-RFLP) fingerprinting. The 16S rRNA gene analysis assessed the predominance of Actinobacteria, Acidobacteria, Proteobacteria, and Bacillus in TCM samples collected at a depth of 0.6 m along with the presence of methanotrophs (Methylocaldum and Methylobacter) and methylotrophs (Methylobacillus). The phylogenetic analysis of pmoA sequences showed the presence of MOB affiliated with Methylomonas, Methylocystis, Methylococcus, and Methylocaldum in addition to as yet uncultivated and uncharacterized methanotrophs. Jaccard’s analysis of T-RFLP profiles at different ground depths revealed a similar MOB composition in soil samples at depths of 0.6 m and 0.7 m, while this similarity was weaker between these samples and those taken at a depth of 2.5 m, in which the genus Methylocaldum was absent. These results correlate the anomalously high temperatures of the farming area of “Terre Calde di Medolla” with the presence of microbial methane-oxidizing bacteria. PMID:27645100

  8. Diversity of Methane-Oxidizing Bacteria in Soils from "Hot Lands of Medolla" (Italy) Featured by Anomalous High-Temperatures and Biogenic CO2 Emission.

    PubMed

    Cappelletti, Martina; Ghezzi, Daniele; Zannoni, Davide; Capaccioni, Bruno; Fedi, Stefano

    2016-12-23

    "Terre Calde di Medolla" (TCM) (literally, "Hot Lands of Medolla") refers to a farming area in Italy with anomalously high temperatures and diffuse emissions of biogenic CO2, which has been linked to CH4 oxidation processes from a depth of 0.7 m to the surface. We herein assessed the composition of the total bacterial community and diversity of methane-oxidizing bacteria (MOB) in soil samples collected at a depth at which the peak temperature was detected (0.6 m). Cultivation-independent methods were used, such as: i) a clone library analysis of the 16S rRNA gene and pmoA (coding for the α-subunit of the particulate methane monooxygenase) gene, and ii) Terminal Restriction Fragment Length Polymorphism (T-RFLP) fingerprinting. The 16S rRNA gene analysis assessed the predominance of Actinobacteria, Acidobacteria, Proteobacteria, and Bacillus in TCM samples collected at a depth of 0.6 m along with the presence of methanotrophs (Methylocaldum and Methylobacter) and methylotrophs (Methylobacillus). The phylogenetic analysis of pmoA sequences showed the presence of MOB affiliated with Methylomonas, Methylocystis, Methylococcus, and Methylocaldum in addition to as yet uncultivated and uncharacterized methanotrophs. Jaccard's analysis of T-RFLP profiles at different ground depths revealed a similar MOB composition in soil samples at depths of 0.6 m and 0.7 m, while this similarity was weaker between these samples and those taken at a depth of 2.5 m, in which the genus Methylocaldum was absent. These results correlate the anomalously high temperatures of the farming area of "Terre Calde di Medolla" with the presence of microbial methane-oxidizing bacteria.

  9. Improved screening procedure for biogenic amine production by lactic acid bacteria.

    PubMed

    Bover-Cid, S; Holzapfel, W H

    1999-12-01

    An improved screening plate method for the detection of amino acid decarboxylase-positive microorganisms (especially lactic acid bacteria) was developed. The suitability and detection level of the designed medium were quantitatively evaluated by confirmation of amine-forming capacity using an HPLC procedure. The potential to produce the biogenic amines (BA) tyramine, histamine, putrescine, and cadaverine, was investigated in a wide number of lactic acid bacteria (LAB) of different origin, including starter cultures, protective cultures, type strains and strains isolated from different food products. Also, several strains of Enterobacteriaceae were examined. Modifications to previously described methods included lowering glucose and sodium chloride concentrations, and increasing the buffer effect with calcium carbonate and potassium phosphate. In addition, pyridoxal-5-phosphate was included as a codecarboxylase factor for its enhancing effect on the amino acid decarboxylase activity. The screening plate method showed a good correlation with the chemical analysis and due to its simplicity it is presented as a suitable and sensitive method to investigate the capacity of biogenic amine production by LAB. Tyramine was the main amine formed by the LAB strains investigated. Enterococci, carnobacteria and some strains of lactobacilli, particularly of Lb. curvatus. Lb. brevis and Lb. buchneri, were the most intensive tyramine formers. Several strains of lactobacilli, Leuconostoc spp., Weissella spp. and pediococci did not show any potential to produce amines. Enterobacteriaceae were associated with cadaverine and putrescine formation. No significant histamine production could be detected for any of the strains tested.

  10. Genetic and temporal relations between formation waters and biogenic methane: Upper Devonian Antrim Shale, Michigan Basin, USA

    NASA Astrophysics Data System (ADS)

    Martini, A. M.; Walter, L. M.; Budai, J. M.; Ku, T. C. W.; Kaiser, C. J.; Schoell, M.

    1998-05-01

    Controversy remains regarding how well geochemical criteria can distinguish microbial from thermogenic methane. Natural gas in most conventional deposits has migrated from a source rock to a reservoir, rarely remaining associated with the original or cogenetic formation waters. We investigated an unusual gas reservoir, the Late Devonian Antrim Shale, in which large volumes of variably saline water are coproduced with gas. The Antrim Shale is organic-rich, of relatively low thermal maturity, extensively fractured, and is both source and reservoir for methane that is generated dominantly by microbial activity. This hydrogeologic setting permits integration of chemical and isotopic compositions of coproduced water and gas, providing a unique opportunity to characterize methane generating mechanisms. The well-developed fracture network provides a conduit for gas and water mass transport within the Antrim Shale and allows invasion of meteoric water from overlying aquifers in the glacial drift. Steep regional concentration gradients in chemical and isotopic data are observed for formation waters and gases; dilute waters grade into dense brines (300,000 ppm) over lateral distances of less than 30 km. Radiogenic ( 14C and 3H) and stable isotope ( 18O and D) analyses of shallow Antrim Shale formation waters and glacial drift groundwaters indicate recharge times from modern to 20,000 yr BP. Carbon isotope compositions of methane from Antrim Shale wells are typical of the established range for thermogenic or mixed gas (δ 13C = -47 to -56‰). However, the unusually high δ 13C values of CO 2 coproduced with methane (˜+22‰) and dissolved inorganic carbon (DIC) in formation waters (˜+28‰) require bacterial mediation. The δD values of methane and coproduced formation water provide the strongest evidence of bacterial methanogenesis. Methane/[ethane + propane] ratios and δ 13C values for ethane indicate: (1) the presence of a thermogenic gas component that increases

  11. Reduction of biogenic amines production by eliminating the PEP4 gene in Saccharomyces cerevisiae during fermentation of Chinese rice wine.

    PubMed

    Guo, Xuewu; Guan, Xiangyu; Wang, Yazhou; Li, Lina; Wu, Deguang; Chen, Yefu; Pei, Huadong; Xiao, Dongguang

    2015-07-01

    Biogenic amines in Chinese rice wine have a potential threat of toxicity to human health. In this study, PEP4 gene in Saccharomyces cerevisiae was knocked out in order to evaluate its effect on biogenic amines production; the enzyme encodes proteinase A (PrA), an enzyme that is responsible for the production of free amino acids. It was found that compared to the wild type strain, the PrA activity and amino acid concentration decreased significantly, and the production of biogenic amines in this knockout strain decreased by 25.5%, from 180.1mg/L to 134.2mg/L. Especially, tyramine, cadaverine and histamine concentrations were also decreased by 57.5%, 24.6% and 54.3%, respectively. The main reason for the decrease of biogenic amines may be due to the low concentration of free amino acids. Our results provide a new strategy to minimize the biogenic amine production during fermentation of Chinese rice wine.

  12. Production of Methane and Water from Crew Plastic Waste

    NASA Technical Reports Server (NTRS)

    Captain, Janine; Santiago, Eddie; Parrish, Clyde; Strayer, Richard F.; Garland, Jay L.

    2008-01-01

    Recycling is a technology that will be key to creating a self sustaining lunar outpost. The plastics used for food packaging provide a source of material that could be recycled to produce water and methane. The recycling of these plastics will require some additional resources that will affect the initial estimate of starting materials that will have to be transported from earth, mainly oxygen, energy and mass. These requirements will vary depending on the recycling conditions. The degredation products of these plastics will vary under different atmospheric conditions. An estimate of the the production rate of methane and water using typical ISRU processes along with the plastic recycling will be presented.

  13. Optimization of microwave pretreatment conditions to maximize methane production and methane yield in mesophilic anaerobic sludge digestion.

    PubMed

    Park, W J; Ahn, J H

    2011-10-01

    The objective of this study was to find optimum microwave pretreatment conditions for methane production and methane yield in anaerobic sludge digestion. The sludge was pretreated using a laboratory-scale industrial microwave unit (2450 MHz frequency). Microwave temperature increase rate (TIR) (2.9-17.1 degrees C/min) and final temperature (FT) (52-108 degrees C) significantly affected solubilization, methane production, and methane yield. Solubilization degree (soluble chemical oxygen demand (COD)/total COD) in the pretreated sludge (3.3-14.7%) was clearly higher than that in the raw sludge (2.6%). Within the design boundaries, the optimum conditions for maximum methane production (2.02 L/L) were TIR = 9.1 degrees C/min and FT = 90 degrees C, and the optimum conditions for maximum methane yield (809 mL/g VS(removed)) were TIR 7.1 degrees C/min and FT = 92 degrees C.

  14. Bacterial bioaugmentation for improving methane and hydrogen production from microalgae

    PubMed Central

    2013-01-01

    Background The recalcitrant cell walls of microalgae may limit their digestibility for bioenergy production. Considering that cellulose contributes to the cell wall recalcitrance of the microalgae Chlorella vulgaris, this study investigated bioaugmentation with a cellulolytic and hydrogenogenic bacterium, Clostridium thermocellum, at different inoculum ratios as a possible method to improve CH4 and H2 production of microalgae. Results Methane production was found to increase by 17?~?24% with the addition of C. thermocellum, as a result of enhanced cell disruption and excess hydrogen production. Furthermore, addition of C. thermocellum enhanced the bacterial diversity and quantities, leading to higher fermentation efficiency. A two-step process of addition of C. thermocellum first and methanogenic sludge subsequently could recover both hydrogen and methane, with a 9.4% increase in bioenergy yield, when compared with the one-step process of simultaneous addition of C. thermocellum and methanogenic sludge. The fluorescence peaks of excitation-emission matrix spectra associated with chlorophyll can serve as biomarkers for algal cell degradation. Conclusions Bioaugmentation with C. thermocellum improved the degradation of C. vulgaris biomass, producing higher levels of methane and hydrogen. The two-step process, with methanogenic inoculum added after the hydrogen production reached saturation, was found to be an energy-efficiency method for hydrogen and methane production. PMID:23815806

  15. Water Management Strategies for Improved Coalbed Methane Production in the Black Warrior Basin

    SciTech Connect

    Pashin, Jack; McIntyre-Redden, Marcella; Mann, Steven; Merkel, David

    2013-10-31

    The modern coalbed methane industry was born in the Black Warrior Basin of Alabama and has to date produced more than 2.6 trillion cubic feet of gas and 1.6 billion barrels of water. The coalbed gas industry in this area is dependent on instream disposal of co-produced water, which ranges from nearly potable sodium-bicarbonate water to hypersaline sodium-chloride water. This study employed diverse analytical methods to characterize water chemistry in light of the regional geologic framework and to evaluate the full range of water management options for the Black Warrior coalbed methane industry. Results reveal strong interrelationships among regional geology, water chemistry, and gas chemistry. Coalbed methane is produced from multiple coal seams in Pennsylvanian-age strata of the Pottsville Coal Interval, in which water chemistry is influenced by a structurally controlled meteoric recharge area along the southeastern margin of the basin. The most important constituents of concern in the produced water include chlorides, ammonia compounds, and organic substances. Regional mapping and statistical analysis indicate that the concentrations of most ionic compounds, metallic substances, and nonmetallic substances correlate with total dissolved solids and chlorides. Gas is effectively produced at pipeline quality, and the only significant impurity is N{sub 2}. Geochemical analysis indicates that the gas is of mixed thermogenic-biogenic origin. Stable isotopic analysis of produced gas and calcite vein fills indicates that widespread late-stage microbial methanogenesis occurred primarily along a CO{sub 2} reduction metabolic pathway. Organic compounds in the produced water appear to have helped sustain microbial communities. Ammonia and ammonium levels increase with total dissolved solids content and appear to have played a role in late-stage microbial methanogenesis and the generation of N{sub 2}. Gas production tends to decline exponentially, whereas water production

  16. Evaluating biochemical methane production from brewer's spent yeast.

    PubMed

    Sosa-Hernández, Ornella; Parameswaran, Prathap; Alemán-Nava, Gibrán Sidney; Torres, César I; Parra-Saldívar, Roberto

    2016-09-01

    Anaerobic digestion treatment of brewer's spent yeast (SY) is a viable option for bioenergy capture. The biochemical methane potential (BMP) assay was performed with three different samples (SY1, SY2, and SY3) and SY1 dilutions (75, 50, and 25 % on a v/v basis). Gompertz-equation parameters denoted slow degradability of SY1 with methane production rates of 14.59-4.63 mL/day and lag phases of 10.72-19.7 days. Performance and kinetic parameters were obtained with the Gompertz equation and the first-order hydrolysis model with SY2 and SY3 diluted 25 % and SY1 50 %. A SY2 25 % gave a 17 % of TCOD conversion to methane as well as shorter lag phase (<1 day). Average estimated hydrolysis constant for SY was 0.0141 (±0.003) day(-1), and SY2 25 % was more appropriate for faster methane production. Methane capture and biogas composition were dependent upon the SY source, and co-digestion (or dilution) can be advantageous.

  17. Skeletonema cf. costatum biogenic silica production rate determinated by PDMPO method

    NASA Astrophysics Data System (ADS)

    Zhang, Guicheng; Leng, Xiaoyun; Feng, Yuanyuan; Li, Xia; Sun, Jun

    2017-04-01

    Diatoms are the only ecological phytoplankton that require silicic acid for growth. They are also the dominant contributor of ocean's total primary productivity. Generation and circulation with silica walls, which the siliceous organisms form, is an important component of the marine biological pump. It is crucial to the study of the operational mechanisms of biological pump with different sea areas. Moreover, it is the key link to the study of global silicon cycle. This paper introduces the basic mechanism of the formation of diatom silica walls and a new way of researching silicic acid metabolism, namely the 2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)- methoxy)phenyl)oxazole (PDMPO) dyeing method. Under a fluorescence microscope after excitation with bright green fluorescence, it can combine with silicic acid to form a complex into the Si deposition within diatom cells. The advantage of this method is that it can monitor the metabolism of silicate after adding PDMPO. For experimentation and sample collection in each of the specified time points, samples were determinated through the unutilized silicic acid, silica dissoluble intracellular and Si deposition within diatom cells, not only using hot alkaline digestions method but also PDMPO dyeing method. Results showed a good linear relationship between PDMPO fluorescent value and biogenic silica concentration. It was also indicated that PDMPO had no deleterious impact on Skeletonema cf. costatum growth for 34 h and was useful for tracking newly-deposited biogenic silica in diatoms' frustules.

  18. Detection of biogenic CO production above vascular cell cultures using a near-room-temperature QC-DFB laser

    NASA Technical Reports Server (NTRS)

    Kosterev, A. A.; Tittel, F. K.; Durante, W.; Allen, M.; Kohler, R.; Gmachl, C.; Capasso, F.; Sivco, D. L.; Cho, A. Y.

    2002-01-01

    We report the first application of pulsed, near-room-temperature quantum cascade laser technology to the continuous detection of biogenic CO production rates above viable cultures of vascular smooth muscle cells. A computer-controlled sequence of measurements over a 9-h period was obtained, resulting in a minimum detectable CO production of 20 ppb in a 1-m optical path above a standard cell-culture flask. Data-processing procedures for real-time monitoring of both biogenic and ambient atmospheric CO concentrations are described.

  19. Methane hydrate research at NETL: Research to make methane production from hydrates a reality

    SciTech Connect

    Taylor, C.E.; Link, D.D.; English, N.

    2007-03-01

    Research is underway at NETL to understand the physical properties of methane hydrates. Five key areas of research that need further investigation have been identified. These five areas, i.e. thermal properties of hydrates in sediments, kinetics of natural hydrate dissociation, hysteresis effects, permeability of sediments to gas flow and capillary pressures within sediments, and hydrate distribution at porous scale, are important to the production models that will be used for producing methane from hydrate deposits. NETL is using both laboratory experiments and computational modeling to address these five key areas. The laboratory and computational research reinforce each other by providing feedback. The laboratory results are used in the computational models and the results from the computational modeling is used to help direct future laboratory research. The data generated at NETL will be used to help fulfill The National Methane Hydrate R&D Program of a “long-term supply of natural gas by developing the knowledge and technology base to allow commercial production of methane from domestic hydrate deposits by the year 2015” as outlined on the NETL Website [NETL Website, 2005. http://www.netl.doe.gov/scngo/Natural%20Gas/hydrates/index.html]. Laboratory research is accomplished in one of the numerous high-pressure hydrate cells available ranging in size from 0.15 mL to 15 L in volume. A dedicated high-pressure view cell within the Raman spectrometer allows for monitoring the formation and dissociation of hydrates. Thermal conductivity of hydrates (synthetic and natural) at a certain temperature and pressure is performed in a NETL-designed cell. Computational modeling studies are investigating the kinetics of hydrate formation and dissociation, modeling methane hydrate reservoirs, molecular dynamics simulations of hydrate formation, dissociation, and thermal properties, and Monte Carlo simulations of hydrate formation and dissociation.

  20. High rate of methane leakage from natural gas production

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-10-01

    Natural gas production is growing as the United States seeks domestic sources of relatively clean energy. Natural gas combustion produces less carbon dioxide emissions than coal or oil for the amount of energy produced. However, one source of concern is that some natural gas leaks to the atmosphere from the extraction point, releasing methane, a potent greenhouse gas.

  1. Zero Valent Iron Significantly Enhances Methane Production from Waste Activated Sludge by Improving Biochemical Methane Potential Rather Than Hydrolysis Rate

    NASA Astrophysics Data System (ADS)

    Liu, Yiwen; Wang, Qilin; Zhang, Yaobin; Ni, Bing-Jie

    2015-02-01

    Anaerobic digestion has been widely applied for waste activated sludge (WAS) treatment. However, methane production from anaerobic digestion of WAS is usually limited by the slow hydrolysis rate and/or poor biochemical methane potential of WAS. This work systematically studied the effects of three different types of zero valent iron (i.e., iron powder, clean scrap and rusty scrap) on methane production from WAS in anaerobic digestion, by using both experimental and mathematical approaches. The results demonstrated that both the clean and the rusty iron scrap were more effective than the iron powder for improving methane production from WAS. Model-based analysis showed that ZVI addition significantly enhanced methane production from WAS through improving the biochemical methane potential of WAS rather than its hydrolysis rate. Economic analysis indicated that the ZVI-based technology for enhancing methane production from WAS is economically attractive, particularly considering that iron scrap can be freely acquired from industrial waste. Based on these results, the ZVI-based anaerobic digestion process of this work could be easily integrated with the conventional chemical phosphorus removal process in wastewater treatment plant to form a cost-effective and environment-friendly approach, enabling maximum resource recovery/reuse while achieving enhanced methane production in wastewater treatment system.

  2. Zero Valent Iron Significantly Enhances Methane Production from Waste Activated Sludge by Improving Biochemical Methane Potential Rather Than Hydrolysis Rate

    PubMed Central

    Liu, Yiwen; Wang, Qilin; Zhang, Yaobin; Ni, Bing-Jie

    2015-01-01

    Anaerobic digestion has been widely applied for waste activated sludge (WAS) treatment. However, methane production from anaerobic digestion of WAS is usually limited by the slow hydrolysis rate and/or poor biochemical methane potential of WAS. This work systematically studied the effects of three different types of zero valent iron (i.e., iron powder, clean scrap and rusty scrap) on methane production from WAS in anaerobic digestion, by using both experimental and mathematical approaches. The results demonstrated that both the clean and the rusty iron scrap were more effective than the iron powder for improving methane production from WAS. Model-based analysis showed that ZVI addition significantly enhanced methane production from WAS through improving the biochemical methane potential of WAS rather than its hydrolysis rate. Economic analysis indicated that the ZVI-based technology for enhancing methane production from WAS is economically attractive, particularly considering that iron scrap can be freely acquired from industrial waste. Based on these results, the ZVI-based anaerobic digestion process of this work could be easily integrated with the conventional chemical phosphorus removal process in wastewater treatment plant to form a cost-effective and environment-friendly approach, enabling maximum resource recovery/reuse while achieving enhanced methane production in wastewater treatment system. PMID:25652244

  3. Zero valent iron significantly enhances methane production from waste activated sludge by improving biochemical methane potential rather than hydrolysis rate.

    PubMed

    Liu, Yiwen; Wang, Qilin; Zhang, Yaobin; Ni, Bing-Jie

    2015-02-05

    Anaerobic digestion has been widely applied for waste activated sludge (WAS) treatment. However, methane production from anaerobic digestion of WAS is usually limited by the slow hydrolysis rate and/or poor biochemical methane potential of WAS. This work systematically studied the effects of three different types of zero valent iron (i.e., iron powder, clean scrap and rusty scrap) on methane production from WAS in anaerobic digestion, by using both experimental and mathematical approaches. The results demonstrated that both the clean and the rusty iron scrap were more effective than the iron powder for improving methane production from WAS. Model-based analysis showed that ZVI addition significantly enhanced methane production from WAS through improving the biochemical methane potential of WAS rather than its hydrolysis rate. Economic analysis indicated that the ZVI-based technology for enhancing methane production from WAS is economically attractive, particularly considering that iron scrap can be freely acquired from industrial waste. Based on these results, the ZVI-based anaerobic digestion process of this work could be easily integrated with the conventional chemical phosphorus removal process in wastewater treatment plant to form a cost-effective and environment-friendly approach, enabling maximum resource recovery/reuse while achieving enhanced methane production in wastewater treatment system.

  4. Unconventional shallow biogenic gas systems

    USGS Publications Warehouse

    Shurr, G.W.; Ridgley, J.L.

    2002-01-01

    Unconventional shallow biogenic gas falls into two distinct systems that have different attributes. Early-generation systems have blanketlike geometries, and gas generation begins soon after deposition of reservoir and source rocks. Late-generation systems have ringlike geometries, and long time intervals separate deposition of reservoir and source rocks from gas generation. For both types of systems, the gas is dominantly methane and is associated with source rocks that are not thermally mature. Early-generation biogenic gas systems are typified by production from low-permeability Cretaceous rocks in the northern Great Plains of Alberta, Saskatchewan, and Montana. The main area of production is on the southeastern margin of the Alberta basin and the northwestern margin of the Williston basin. The huge volume of Cretaceous rocks has a generalized regional pattern of thick, non-marine, coarse clastics to the west and thinner, finer grained marine lithologies to the east. Reservoir rocks in the lower part tend to be finer grained and have lower porosity and permeability than those in the upper part. Similarly, source beds in the units have higher values of total organic carbon. Patterns of erosion, deposition, deformation, and production in both the upper and lower units are related to the geometry of lineament-bounded basement blocks. Geochemical studies show that gas and coproduced water are in equilibrium and that the fluids are relatively old, namely, as much as 66 Ma. Other examples of early-generation systems include Cretaceous clastic reservoirs on the southwestern margin of Williston basin and chalks on the eastern margin of the Denver basin. Late-generation biogenic gas systems have as an archetype the Devonian Antrim Shale on the northern margin of the Michigan basin. Reservoir rocks are fractured, organic-rich black shales that also serve as source rocks. Although fractures are important for production, the relationships to specific geologic structures are

  5. The evolution and distribution of methane in Lake Champlain sediments

    SciTech Connect

    Thibodeau, P.M. . Dept. of Geology)

    1993-03-01

    Regions of Lake Champlain sediments are acoustically impenetrable to the energy emitted from high resolution, low energy sub-bottom seismic profiling apparatus. This anomolous behavior is caused by the presence of interstitial methane gas which absorbs the wave energy and thus prevents the formation of well-defined seismic boundaries. Through gas chromatographic and carbon isotope analyses, the methane gas contained in the recent sediments of Lake Champlain has been demonstrated to be biogenic in origin. The production of biogenic methane occurs as a result of a series of coupled oxidation-reduction reactions occurring within the upper two meters beneath the sediment-water interface.

  6. Polyhydroxyalkanoates in waste activated sludge enhances anaerobic methane production through improving biochemical methane potential instead of hydrolysis rate

    NASA Astrophysics Data System (ADS)

    Wang, Qilin; Sun, Jing; Zhang, Chang; Xie, Guo-Jun; Zhou, Xu; Qian, Jin; Yang, Guojing; Zeng, Guangming; Liu, Yiqi; Wang, Dongbo

    2016-01-01

    Anaerobic sludge digestion is the main technology for sludge reduction and stabilization prior to sludge disposal. Nevertheless, methane production from anaerobic digestion of waste activated sludge (WAS) is often restricted by the poor biochemical methane potential and slow hydrolysis rate of WAS. This work systematically investigated the effect of PHA levels of WAS on anaerobic methane production, using both experimental and mathematical modeling approaches. Biochemical methane potential tests showed that methane production increased with increased PHA levels in WAS. Model-based analysis suggested that the PHA-based method enhanced methane production by improving biochemical methane potential of WAS, with the highest enhancement being around 40% (from 192 to 274 L CH4/kg VS added; VS: volatile solid) when the PHA levels increased from 21 to 143 mg/g VS. In contrast, the hydrolysis rate (approximately 0.10 d‑1) was not significantly affected by the PHA levels. Economic analysis suggested that the PHA-based method could save $1.2/PE/y (PE: population equivalent) in a typical wastewater treatment plant (WWTP). The PHA-based method can be easily integrated into the current WWTP to enhance methane production, thereby providing a strong support to the on-going paradigm shift in wastewater management from pollutant removal to resource recovery.

  7. Polyhydroxyalkanoates in waste activated sludge enhances anaerobic methane production through improving biochemical methane potential instead of hydrolysis rate.

    PubMed

    Wang, Qilin; Sun, Jing; Zhang, Chang; Xie, Guo-Jun; Zhou, Xu; Qian, Jin; Yang, Guojing; Zeng, Guangming; Liu, Yiqi; Wang, Dongbo

    2016-01-21

    Anaerobic sludge digestion is the main technology for sludge reduction and stabilization prior to sludge disposal. Nevertheless, methane production from anaerobic digestion of waste activated sludge (WAS) is often restricted by the poor biochemical methane potential and slow hydrolysis rate of WAS. This work systematically investigated the effect of PHA levels of WAS on anaerobic methane production, using both experimental and mathematical modeling approaches. Biochemical methane potential tests showed that methane production increased with increased PHA levels in WAS. Model-based analysis suggested that the PHA-based method enhanced methane production by improving biochemical methane potential of WAS, with the highest enhancement being around 40% (from 192 to 274 L CH4/kg VS added; VS: volatile solid) when the PHA levels increased from 21 to 143 mg/g VS. In contrast, the hydrolysis rate (approximately 0.10 d(-1)) was not significantly affected by the PHA levels. Economic analysis suggested that the PHA-based method could save $1.2/PE/y (PE: population equivalent) in a typical wastewater treatment plant (WWTP). The PHA-based method can be easily integrated into the current WWTP to enhance methane production, thereby providing a strong support to the on-going paradigm shift in wastewater management from pollutant removal to resource recovery.

  8. Polyhydroxyalkanoates in waste activated sludge enhances anaerobic methane production through improving biochemical methane potential instead of hydrolysis rate

    PubMed Central

    Wang, Qilin; Sun, Jing; Zhang, Chang; Xie, Guo-Jun; Zhou, Xu; Qian, Jin; Yang, Guojing; Zeng, Guangming; Liu, Yiqi; Wang, Dongbo

    2016-01-01

    Anaerobic sludge digestion is the main technology for sludge reduction and stabilization prior to sludge disposal. Nevertheless, methane production from anaerobic digestion of waste activated sludge (WAS) is often restricted by the poor biochemical methane potential and slow hydrolysis rate of WAS. This work systematically investigated the effect of PHA levels of WAS on anaerobic methane production, using both experimental and mathematical modeling approaches. Biochemical methane potential tests showed that methane production increased with increased PHA levels in WAS. Model-based analysis suggested that the PHA-based method enhanced methane production by improving biochemical methane potential of WAS, with the highest enhancement being around 40% (from 192 to 274 L CH4/kg VS added; VS: volatile solid) when the PHA levels increased from 21 to 143 mg/g VS. In contrast, the hydrolysis rate (approximately 0.10 d−1) was not significantly affected by the PHA levels. Economic analysis suggested that the PHA-based method could save $1.2/PE/y (PE: population equivalent) in a typical wastewater treatment plant (WWTP). The PHA-based method can be easily integrated into the current WWTP to enhance methane production, thereby providing a strong support to the on-going paradigm shift in wastewater management from pollutant removal to resource recovery. PMID:26791952

  9. Rate of production, dissolution and accumulation of biogenic solids in the ocean

    NASA Technical Reports Server (NTRS)

    Arrhenius, G.

    1988-01-01

    The equatorial current system, by its response to global circulation changes, provides a unique recording mechanism for long range climatic oscillations. A permanent record of the changes in rate of upwelling and organic production is generated in the equatorial deep sea sediments, particularly by such biogenic components which are unaffected by secondary dissolution. In order to determine the rates of accumulation of various sedimentary components, a reliable differential measurement of age of the strata must be obtained. Various approaches to this problem are reviewed, and sources of error discussed. Secondary dissolution of calcium carbonate introduces a substantial and variable difference between the dissolution-modified, and hence a priori unknown, rate of deposition on one hand and the rate of accumulation, derivable from the observed concentration, on the other. The cause and magnitude of these variations are of importance, particularly since some current dating schemes are based on assumed constancy in the rate of accumulation of this and, in some cases, also all other sedimentary components. The concepts used in rate evaluation are discussed with emphasis on the difference between the state of dissolution, an observable property of the sediment, and the rate of dissolution, a parameter that requires deduction of the carbonate fraction dissolved, and of the time differential. As a most likely cause of the enhanced state of dissolution of the interglacial carbonate sediments is proposed the lowered rates of biogenic production and deposition, which cause longer exposure of the carbonate microfossils to corrosion in the bioturbated surface layer of the sediment. Historical perspective is included in the discussion in view of the dedication of the Symposium to Hans Pettersson, the leader of the Swedish Deep Sea Expedition 1947-1948, an undertaking that opened a new era in deep sea research and planetary dynamics.

  10. Rate of production, dissolution and accumulation of biogenic solids in the ocean.

    PubMed

    Arrhenius, G

    1988-01-01

    The equatorial current system, by its response to global circulation changes, provides a unique recording mechanism for long range climatic oscillations. A permanent record of the changes in rate of upwelling and organic production is generated in the equatorial deep sea sediments, particularly by such biogenic components which are unaffected by secondary dissolution. In order to determine the rates of accumulation of various sedimentary components, a reliable differential measurement of age of the strata must be obtained. Various approaches to this problem are reviewed, and sources of error discussed. Secondary dissolution of calcium carbonate introduces a substantial and variable difference between the dissolution-modified, and hence a priori unknown, rate of deposition on one hand and the rate of accumulation, derivable from the observed concentration, on the other. The cause and magnitude of these variations are of importance, particularly since some current dating schemes are based on assumed constancy in the rate of accumulation of this and, in some cases, also all other sedimentary components. The concepts used in rate evaluation are discussed with emphasis on the difference between the state of dissolution, an observable property of the sediment, and the rate of dissolution, a parameter that requires deduction of the carbonate fraction dissolved, and of the time differential. As a most likely cause of the enhanced state of dissolution of the interglacial carbonate sediments is proposed the lowered rates of biogenic production and deposition, which cause longer exposure of the carbonate microfossils to corrosion in the bioturbated surface layer of the sediment. Historical perspective is included in the discussion in view of the dedication of the Symposium to Hans Pettersson, the leader of the Swedish Deep Sea Expedition 1947-1948, an undertaking that opened a new era in deep sea research and planetary dynamics.

  11. Screening of biogenic amine production by coagulase-negative staphylococci isolated during industrial Spanish dry-cured ham processes.

    PubMed

    Landeta, Gerardo; de Las Rivas, Blanca; Carrascosa, Alfonso V; Muñoz, Rosario

    2007-12-01

    The potential to produce biogenic amines was investigated for 56 coagulase-negative staphylococci isolated during industrial Spanish dry-cured ham processes. The presence of biogenic amines from bacterial cultures was determined by thin-layer chromatography. The percentage of strains that decarboxylated amino acids was very low (3.6%). The only staphylococci with aminogenic capacity were an histamine-producing Staphylococcus capitis strain, and a Staphylococcus lugdunensis strain that simultaneously produced putrescine and cadaverine. In both strains, PCR was used to confirm the presence of the genes encoding the amino acid decarboxylases responsible for the synthesis of these amines. This study reveals that production of biogenic amines is not a widely distributed property among the staphylococci isolated from Spanish dry-cured hams.

  12. Carbon and hydrogen isotope composition and C-14 concentration in methane from sources and from the atmosphere: Implications for a global methane budget

    NASA Technical Reports Server (NTRS)

    Wahlen, Martin

    1994-01-01

    The topics covered include the following: biogenic methane studies; forest soil methane uptake; rice field methane sources; atmospheric measurements; stratospheric samples; Antarctica; California; and Germany.

  13. Methane production and consumption in grassland and boreal ecosystems

    NASA Technical Reports Server (NTRS)

    Schimel, David S.; Burke, Ingrid C.; Johnston, Carol; Pastor, John

    1994-01-01

    The objectives of the this project were to develop a mechanistic understanding of methane production and oxidation suitable for incorporation into spatially explicit models for spatial extrapolation. Field studies were undertaken in Minnesota, Canada, and Colorado to explore the process controls over the two microbial mediated methane transformations in a range of environments. Field measurements were done in conjunction with ongoing studies in Canada (the Canadian Northern Wetlands Projects: NOWES) and in Colorado (The Shortgrass Steppe Long Term Ecological Research Project: LTER). One of the central hypotheses of the proposal was that methane production should be substrate limited, as well as being controlled by physical variables influencing microbial activity (temperature, oxidation status, and pH). Laboratory studies of peats from Canada and Minnesota (Northern and Southern Boreal) were conducted with amendments of a methanogenic substrate at multiple temperatures and at multiple pHs (the latter by titrating samples). The studies showed control by substrate, pH, and temperature in order in anaerobic samples. Field and laboratory manipulations of natural plant litter, rather than an acetogenic substrate, showed similarly large effects. The studies concluded that substrate is an important control over methanogenesis, that substrate availability in the field is closely coupled to the chemistry of the dominant vegetation influencing its decomposition rate, that most methane is produced from recent plant litter, and that landscape changes in pH are an important control, highly correlated with vegetation.

  14. Methane production from agricultural residues - A short review

    NASA Astrophysics Data System (ADS)

    Chen, Y.-R.; Varel, V. H.; Hashimoto, A. G.

    1980-12-01

    This paper summarizes the methanogenesis process, the environmental requirement, kinetics, energy requirements, and methane production cost of methane fermentation systems. Available data of biodegradability of the residue and kinetic equations can be used to predict the methane production under different operating conditions. The optimum condition for fermenting beef cattle residue is operating at a thermophilic temperature (55 C) with an influent concentration of 80 g of VS/L. This produces yields of 3.96 L of CH4/L fermenter-day at 5 days retention time. It is apparent that the anaerobic fermentation process is technically feasible. However, only at plant sizes larger than 300 Mg TS/day will the anerobic fermentation system produce methane gas comparable to the current natural gas price. If the effluent can be used as a feed supplement for livestock, the anaerobic fermentation system for livestock residue will be economically feasible at a plant size between 3 and 6 Mg TS/day. This corresponds to beef cattle feedlots between 1000 and 2000 head.

  15. Methane production from agricultural residues - A short review

    SciTech Connect

    Chen, Y.R.; Varel, V.H.; Hashimoto, A.G.

    1980-12-01

    This paper summarizes the methanogenesis process, the environmental requirement, kinetics, energy requirements, and methane production cost of methane fermentation systems. Available data of biodegradability of the residue and kinetic equations can be used to predict the methane production under different operating conditions. The optimum condition for fermenting beef cattle residue is operating at a thermophilic temperature (55/sup 0/C) with an influent concentration of 80 g of VS/L. This produces yields of 3.96 L of CH4/L fermenter-day at 5 days retention time. It is apparent that the anaerobic fermentation process is technically feasible. However, only at plant sizes larger than 300 Mg TS/day will the anerobic fermentation system produce methane gas comparable to the current natural gas price. If the effluent can be used as a feed supplement for livestock, the anaerobic fermentation system for livestock residue will be economically feasible at a plant size between 3 and 6 Mg TS/day. This corresponds to beef cattle feedlots between 1000 and 2000 head.

  16. Chemical and stable isotopic evidence for water/rock interaction and biogenic origin of coalbed methane, Fort Union Formation, Powder River Basin, Wyoming and Montana U.S.A

    USGS Publications Warehouse

    Rice, C.A.; Flores, R.M.; Stricker, G.D.; Ellis, M.S.

    2008-01-01

    Significant amounts (> 36??million m3/day) of coalbed methane (CBM) are currently being extracted from coal beds in the Paleocene Fort Union Formation of the Powder River Basin of Wyoming and Montana. Information on processes that generate methane in these coalbed reservoirs is important for developing methods that will stimulate additional production. The chemical and isotopic compositions of gas and ground water from CBM wells throughout the basin reflect generation processes as well as those that affect water/rock interaction. Our study included analyses of water samples collected from 228 CBM wells. Major cations and anions were measured for all samples, ??DH2O and ??18OH2O were measured for 199 of the samples, and ??DCH4 of gas co-produced with water was measured for 100 of the samples. Results show that (1) water from Fort Union Formation coal beds is exclusively Na-HCO3-type water with low dissolved SO4 content (median < 1??mg/L) and little or no dissolved oxygen (< 0.15??mg/L), whereas shallow groundwater (depth generally < 120??m) is a mixed Ca-Mg-Na-SO4-HCO3 type; (2) water/rock interactions, such as cation exchange on clay minerals and precipitation/dissolution of CaCO3 and SO4 minerals, account for the accumulation of dissolved Na and depletion of Ca and Mg; (3) bacterially-mediated oxidation-reduction reactions account for high HCO3 (270-3310??mg/L) and low SO4 (median < 0.15??mg/L) values; (4) fractionation between ??DCH4 (- 283 to - 328 per mil) and ??DH2O (- 121 to - 167 per mil) indicates that the production of methane is primarily by biogenic CO2 reduction; and (5) values of ??DH2O and ??18OH2O (- 16 to - 22 per mil) have a wide range of values and plot near or above the global meteoric water line, indicating that the original meteoric water has been influenced by methanogenesis and by being mixed with surface and shallow groundwater.

  17. The Impact of Carvacrol on Ammonia and Biogenic Amine Production by Common Foodborne Pathogens.

    PubMed

    Özogul, Fatih; Kaçar, Çiğdem; Kuley, Esmeray

    2015-12-01

    The impact of carvacrol at different levels (0.1%, 0.5%, and 1%) on ammonia (AMN) and biogenic amines (BAs) production by 8 common foodborne pathogens (FBPs) (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, Listeria monocytogenes, Aeromonas hydrophila, and Salmonella Paratyphi A) was studied using a rapid high-performance liquid chromatography method. Significant differences among bacteria (P < 0.05) in AMN and BA production were observed using a tyrosine decarboxylase broth. Tyramine, dopamine, agmatine, spermine, and putrescine were the main amines produced by the bacteria. Tyramine production by P. aeruginosa was the highest (967 mg/L), whereas K. pneumoniae was the poorest tyramine producer (6.42 mg/L). AMN and BA production varied significantly depending on carvacrol levels and the specific bacterial strains. Tyramine production for all bacterial strains was significantly suppressed by addition of carvacrol at levels of 0.5% and 1%, but not 0.1%. Consequently, the effect of carvacrol on BA and AMN formation by FBP was dependent on bacterial strain as well as carvacrol level.

  18. Hydrogen production from methane through catalytic partial oxidation reactions

    NASA Astrophysics Data System (ADS)

    Freni, S.; Calogero, G.; Cavallaro, S.

    This paper reviews recent developments in syn-gas production processes used for partial methane oxidation with and/or without steam. In particular, we examined different process charts (fixed bed, fluidised bed, membrane, etc.), kinds of catalysts (powders, foams, monoliths, etc.) and catalytically active phases (Ni, Pt, Rh, etc.). The explanation of the various suggested technical solutions accounted for the reaction mechanism that may selectively lead to calibrated mixtures of CO and H 2 or to the unwanted formation of products of total oxidation (CO 2 and H 2O) and pyrolysis (coke). Moreover, the new classes of catalysts allow the use of small reactors to treat large amounts of methane (monoliths) or separate hydrogen in situ from the other reaction products (membrane). This leads to higher conversions and selectivity than could have been expected thermodynamically. Although catalysts based on Rh are extremely expensive, they can be used to minimise H 2O formation by maximising H 2 yield.

  19. The Influence of Pyrogenic, Biogenic and Anthropogenic Emissions on Ozone Production Downwind from Boreal Forest Fires

    NASA Astrophysics Data System (ADS)

    Finch, Douglas; Palmer, Paul

    2016-04-01

    Boreal forest fires emit pollutants that can have a strong influence on downwind surface ozone concentrations, with potential implications for exceeding air quality regulations. The influence of the mixing of pyrogenic, biogenic and anthropogenic emissions on ozone is not well understood. Using the nested 0.5° latitude x 0.667° longitude GEOS-Chem chemical transport model we track biomass burning plumes in North America. We identify the changes in key chemical reactions within these plumes as well as the sensitivity of ozone to the different emission sources. We illustrate the importance of this method using a case study of a multi-day forest fire during the BORTAS aircraft campaign over eastern Canada during summer 2011. We focus on emissions from the fire on the 17th of July and follow the plume for eight days. After the initial 24 hours of pyrogenic emissions the main source of VOCs is biogenic with increasing emissions from anthropogenic sources including outflow from Quebec City and Newfoundland. Using a Lagrangian framework, we show that the ozone production efficiency (OPE) of this plume decreases steadily as it moves away from the fire but increases rapidly as the plume reaches the east coast of Canada. Using a Eulerian framework we show that ozone mixing ratios of a east coast receptor region increase by approximately 15% even though the ozone tendency of the regional air mass is negative, which we find is due to the arrival of ozone precursors in the plume. We also consider the contribution of anthropogenic outflow over Nova Scotia that originates from the eastern seaboard of the United States to the local chemistry. Using these sensitivity model runs we generate a chemical reaction narrative for the plume trajectory that helps to understand the attribution of observed ozone variations.

  20. Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications.

    PubMed

    Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto; Kerminen, Veli-Matti; Junninen, Heikki; Paasonen, Pauli; Stratmann, Frank; Herrmann, Hartmut; Guenther, Alex B; Worsnop, Douglas R; Kulmala, Markku; Ehn, Mikael; Sipilä, Mikko

    2015-06-09

    Oxidation products of monoterpenes and isoprene have a major influence on the global secondary organic aerosol (SOA) burden and the production of atmospheric nanoparticles and cloud condensation nuclei (CCN). Here, we investigate the formation of extremely low volatility organic compounds (ELVOC) from O3 and OH radical oxidation of several monoterpenes and isoprene in a series of laboratory experiments. We show that ELVOC from all precursors are formed within the first minute after the initial attack of an oxidant. We demonstrate that under atmospherically relevant concentrations, species with an endocyclic double bond efficiently produce ELVOC from ozonolysis, whereas the yields from OH radical-initiated reactions are smaller. If the double bond is exocyclic or the compound itself is acyclic, ozonolysis produces less ELVOC and the role of the OH radical-initiated ELVOC formation is increased. Isoprene oxidation produces marginal quantities of ELVOC regardless of the oxidant. Implementing our laboratory findings into a global modeling framework shows that biogenic SOA formation in general, and ELVOC in particular, play crucial roles in atmospheric CCN production. Monoterpene oxidation products enhance atmospheric new particle formation and growth in most continental regions, thereby increasing CCN concentrations, especially at high values of cloud supersaturation. Isoprene-derived SOA tends to suppress atmospheric new particle formation, yet it assists the growth of sub-CCN-size primary particles to CCN. Taking into account compound specific monoterpene emissions has a moderate effect on the modeled global CCN budget.

  1. Seafloor Deformation Monitoring for Methane Hydrate Production Test

    NASA Astrophysics Data System (ADS)

    Yokoyama, T.; Matsuda, S.; Takeshima, J.; Sano, K.; Nakatsuka, Y.

    2014-12-01

    In order to observe the seafloor deformation during methane hydrate production test, we have developed a monitoring system for seafloor subsidence and inclination. According to simulation of seafloor deformation around the production well, the range of subsidence will be from 10cm to 30 cm with the continuous production of methane hydrate in a month. This monitoring system has been examined in the offshore of Suruga Bay which has water depth more than 1000m. All the features of this system were confirmed by the examination at the deep sea area. Subsidence is measured with change of water pressure on the seafloor. A pressure gauge we selected is applied a quartz crystal resonator. The range of the pressure gauge is 0 to 1,400m, the resolution is 0.014mm, and actual accuracy is around 10mm in conversion to water level. An inclinometer we selected is applied liquid electrolyte. The range of the inclinometer is from +30 to -30 degreee, resolution is 0.001degree, and actual accuracy is around 0.03-0.3degree depending on measuring condition. We have monitored by using this system during the production test of methane hydrate at East Nankai trough in the beginning of 2013.This work was carried out by OYO corporation with the support of JOGMEC which is a member of MH21 consortium sponsored by Ministry of Economy, Trade and Industry in Japan.

  2. Methanogens rapidly transition from methane production to iron reduction.

    PubMed

    Sivan, O; Shusta, S S; Valentine, D L

    2016-03-01

    Methanogenesis, the microbial methane (CH4 ) production, is traditionally thought to anchor the mineralization of organic matter as the ultimate respiratory process in deep sediments, despite the presence of oxidized mineral phases, such as iron oxides. This process is carried out by archaea that have also been shown to be capable of reducing iron in high levels of electron donors such as hydrogen. The current pure culture study demonstrates that methanogenic archaea (Methanosarcina barkeri) rapidly switch from methanogenesis to iron-oxide reduction close to natural conditions, with nitrogen atmosphere, even when faced with substrate limitations. Intensive, biotic iron reduction was observed following the addition of poorly crystalline ferrihydrite and complex organic matter and was accompanied by inhibition of methane production. The reaction rate of this process was of the first order and was dependent only on the initial iron concentrations. Ferrous iron production did not accelerate significantly with the addition of 9,10-anthraquinone-2,6-disulfonate (AQDS) but increased by 11-28% with the addition of phenazine-1-carboxylate (PCA), suggesting the possible role of methanophenazines in the electron transport. The coupling between ferrous iron and methane production has important global implications. The rapid transition from methanogenesis to reduction of iron-oxides close to the natural conditions in sediments may help to explain the globally-distributed phenomena of increasing ferrous concentrations below the traditional iron reduction zone in the deep 'methanogenic' sediment horizon, with implications for metabolic networking in these subsurface ecosystems and in past geological settings.

  3. Methyl chloride production from methane over lanthanum-based catalysts.

    PubMed

    Podkolzin, Simon G; Stangland, Eric E; Jones, Mark E; Peringer, Elvira; Lercher, Johannes A

    2007-03-07

    The mechanism of selective production of methyl chloride by a reaction of methane, hydrogen chloride, and oxygen over lanthanum-based catalysts was studied. The results suggest that methane activation proceeds through oxidation-reduction reactions on the surface of catalysts with an irreducible metal-lanthanum, which is significantly different from known mechanisms for oxidative chlorination. Activity and spectroscopic measurements show that lanthanum oxychloride (LaOCl), lanthanum trichloride (LaCl3), and lanthanum phases with an intermediate extent of chlorination are all active for this reaction. The catalyst is stable with no noticeable deactivation after three weeks of testing. Kinetic measurements suggest that methane activation proceeds on the surface of the catalyst. Flow and pulse experiments indicate that the presence of hydrogen chloride is not required for activity, and its role appears to be limited to maintaining the extent of catalyst chlorination. In contrast, the presence of gas-phase oxygen is essential for catalytic activity. Density-functional theory calculations suggest that oxygen can activate surface chlorine species by adsorbing dissociatively and forming OCl surface species, which can serve as an active site for methane activation. The proposed mechanism, thus, involves changing of the formal oxidation state of surface chlorine from -1 to +1 without any changes in the oxidation state of the underlying metal.

  4. Methane production from bicarbonate and acetate in an anoxic marine sediment

    NASA Technical Reports Server (NTRS)

    Crill, P. M.; Martens, C. S.

    1986-01-01

    Methane production from C-14 labeled bicarbonate and acetate was measured over the top 28 cm of anoxic Cape Lookout Bight sediments during the summer of 1983. The depth distribution and magnitude of summed radioisotopically determined rates compare well with previous measurements of total methane production and the sediment-water methane flux. Methane production from CO2 reduction and acetate fermentation accounts for greater than 80 percent of the total production rate and sediment-water flux. Methane production from bicarbonate was found to occur in all depth intervals sampled except those in the top 2 cm, whereas significant methane production from acetate only occurred at depths below 10 cm where sulfate was exhausted. Acetate provided 20 to 29 percent of the measured methane production integrated over the top 30 cm of the sediments.

  5. Consistent quantification of climate impacts due to biogenic carbon storage across a range of bio-product systems

    SciTech Connect

    Guest, Geoffrey Bright, Ryan M. Cherubini, Francesco Strømman, Anders H.

    2013-11-15

    Temporary and permanent carbon storage from biogenic sources is seen as a way to mitigate climate change. The aim of this work is to illustrate the need to harmonize the quantification of such mitigation across all possible storage pools in the bio- and anthroposphere. We investigate nine alternative storage cases and a wide array of bio-resource pools: from annual crops, short rotation woody crops, medium rotation temperate forests, and long rotation boreal forests. For each feedstock type and biogenic carbon storage pool, we quantify the carbon cycle climate impact due to the skewed time distribution between emission and sequestration fluxes in the bio- and anthroposphere. Additional consideration of the climate impact from albedo changes in forests is also illustrated for the boreal forest case. When characterizing climate impact with global warming potentials (GWP), we find a large variance in results which is attributed to different combinations of biomass storage and feedstock systems. The storage of biogenic carbon in any storage pool does not always confer climate benefits: even when biogenic carbon is stored long-term in durable product pools, the climate outcome may still be undesirable when the carbon is sourced from slow-growing biomass feedstock. For example, when biogenic carbon from Norway Spruce from Norway is stored in furniture with a mean life time of 43 years, a climate change impact of 0.08 kg CO{sub 2}eq per kg CO{sub 2} stored (100 year time horizon (TH)) would result. It was also found that when biogenic carbon is stored in a pool with negligible leakage to the atmosphere, the resulting GWP factor is not necessarily − 1 CO{sub 2}eq per kg CO{sub 2} stored. As an example, when biogenic CO{sub 2} from Norway Spruce biomass is stored in geological reservoirs with no leakage, we estimate a GWP of − 0.56 kg CO{sub 2}eq per kg CO{sub 2} stored (100 year TH) when albedo effects are also included. The large variance in GWPs across the range of

  6. Potential role of stabilized Criegee radicals in sulfuric acid production in a high biogenic VOC environment.

    PubMed

    Kim, Saewung; Guenther, Alex; Lefer, Barry; Flynn, James; Griffin, Robert; Rutter, Andrew P; Gong, Longwen; Cevik, Basak Karakurt

    2015-03-17

    We present field observations made in June 2011 downwind of Dallas-Fort Worth, TX, and evaluate the role of stabilized Criegee radicals (sCIs) in gaseous sulfuric acid (H2SO4) production. Zero-dimensional model calculations show that sCI from biogenic volatile organic compounds composed the majority of the sCIs. The main uncertainty associated with an evaluation of H2SO4 production from the sCI reaction channel is the lack of experimentally determined reaction rates for sCIs formed from isoprene ozonolysis with SO2 along with systematic discrepancies in experimentally derived reaction rates between other sCIs and SO2 and water vapor. In general, the maximum of H2SO4 production from the sCI channel is found in the late afternoon as ozone increases toward the late afternoon. The sCI channel, however, contributes minor H2SO4 production compared with the conventional OH channel in the mid-day. Finally, the production and the loss rates of H2SO4 are compared. The application of the recommended mass accommodation coefficient causes significant overestimation of H2SO4 loss rates compared with H2SO4 production rates. However, the application of a lower experimental value for the mass accommodation coefficient provides good agreement between the loss and production rates of H2SO4. The results suggest that the recommended coefficient for the H2O surface may not be suitable for this relatively dry environment.

  7. Time-Lapse Geophysical Measurements targeting Spatial and Temporal Variability in Biogenic Gas Production from Peat Soils in a Hydrologically Controlled Wetland in the Florida Everglades

    NASA Astrophysics Data System (ADS)

    Wright, W. J.; Shahan, T.; Sharp, N.; Comas, X.

    2015-12-01

    Peat soils are known to release globally significant amounts of methane (CH4) and carbon dioxide (CO2) to the atmosphere. However, uncertainties still remain regarding the spatio-temporal distribution of gas accumulations and triggering mechanisms of gas releasing events. Furthermore, most research on peatland gas dynamics has traditionally been focused on high latitude peatlands. Therefore, understanding gas dynamics in low-latitude peatlands (e.g. the Florida Everglades) is key to global climate research. Recent studies in the Everglades have demonstrated that biogenic gas flux values may vary when considering different temporal and spatial scales of measurements. The work presented here targets spatial variability in gas production and release at the plot scale in an approximately 85 m2 area, and targets temporal variability with data collected during the spring months of two different years. This study is located in the Loxahatchee Impoundment Landscape Assessment (LILA), a hydrologically controlled, landscape scale (30 Ha) model of the Florida Everglades. Ground penetrating radar (GPR) has been used in the past to investigate biogenic gas dynamics in peat soils, and is used in this study to monitor changes of in situ gas storage. Each year, a grid of GPR profiles was collected to image changes in gas distribution in 2d on a weekly basis, and several flux chambers outfitted with time-lapse cameras captured high resolution (hourly) gas flux measurements inside the GPR grid. Combining these methods allows us to use a mass balance approach to estimate spatial variability in gas production rates, and capture temporal variability in gas flux rates.

  8. Multiple sulfur and carbon isotope composition of sediments from the Belingwe Greenstone Belt (Zimbabwe): A biogenic methane regulation on mass independent fractionation of sulfur during the Neoarchean?

    NASA Astrophysics Data System (ADS)

    Thomazo, Christophe; Nisbet, Euan G.; Grassineau, Nathalie V.; Peters, Marc; Strauss, Harald

    2013-11-01

    To explore the linkage between mass-independent sulfur isotope fractionation (MIF-S) and δ13Corg excursions during the Neoarchean, as well as the contemporary redox state and biogeochemical cycling of carbon and sulfur, we report the results of a detailed carbon and multiple sulfur (δ34S, δ33S, δ36S) isotopic study of the ∼2.7 Ga Manjeri and ∼2.65 Ga Cheshire formations of the Ngezi Group (Belingwe Greenstone Belt, Zimbabwe). Multiple sulfur isotope data show non-zero Δ33S and Δ36S values for sediments older than 2.4 Ga (i.e. prior to the Great Oxidation Event, GOE), indicating MIF-S thought to be associated with low atmospheric oxygen concentration. However, in several 2.7-2.5 Ga Neoarchean localities, small-scale variations in MIF-S signal (magnitude) seem to correlate with negative excursion in δ13Corg, possibly reflecting a global connection between the relative reaction rate of different MIF-S source reaction and sulfur exit channels and the biogenic flux of methane into the atmosphere during periods of localized, microbiologically mediated, shallow surface-water oxygenation. The Manjeri Formation black shales studied here display a wide range of δ13Corg between -35.4‰ and -16.2‰ (average of -30.3 ± 6.0‰, 1σ), while the Cheshire Formation shales have δ13Corg between -47.7‰ and -35.1‰ (average -41.3 ± 3‰, 1σ). The δ34S values of sedimentary sulfides from Manjeri Formation vary between -15.15‰ and +2.37‰ (average -1.71 ± 4.76‰, 1σ), showing very small and mostly negative Δ33S values varying from -0.58‰ to 0.87‰ (average 0.02 ± 0.43‰, 1σ). Cheshire Formation black shale sulfide samples measured in this study have δ34S values ranging from -2.11‰ to 2.39‰ (average 0.25 ± 1.08‰, 1σ) and near zero and solely positive Δ33S anomalies between 0.14‰ and 1.17‰ (average 0.56 ± 0.29‰, 1σ). Moreover, Δ36S/Δ33S in the two formations are comparable with a slope of -1.38 (Manjeri Formation) and -1.67 (Cheshire

  9. Dynamics of methane production, sulfate reduction, and denitrification in a permanently waterlogged alder swamp

    SciTech Connect

    Westermann, P.; Ahring, B.K.

    1987-10-01

    The dynamics of sulfate reduction, methane production, and denitrification were investigated in a permanently waterlogged alder swamp. Molybdate, an inhibitor of sulfate reduction, stimulated methane production in soil slurries, thus suggesting competition for common substrates between sulfate-reducing and methane-producing bacteria. Acetate, hydrogen, and methanol were found to stimulate both sulfate reduction and methane production, while trimethylamine mainly stimulated methane production. Nitrate addition reduced both methane production and sulfate reduction, either as a consequence of competition of poisoning of the bacteria. Sulfate-reducing bacteria were only slightly limited by the availability of electron acceptors, while denitrifying bacteria were seriously limited by low nitrate concentrations. Arrhenius plots of the three processes revealed different responses to temperature changes in the slurries. Methane production was most sensitive to temperature changes, followed by denitrification and sulfate reduction. No significant differences between slope patterns were observed when comparing summer and winter measurements, indicating similar populations regarding temperature responses.

  10. Short communication: Genetic study of methane production predicted from milk fat composition in dairy cows.

    PubMed

    van Engelen, S; Bovenhuis, H; Dijkstra, J; van Arendonk, J A M; Visker, M H P W

    2015-11-01

    Dairy cows produce enteric methane, a greenhouse gas with 25 times the global warming potential of CO2. Breeding could make a permanent, cumulative, and long-term contribution to methane reduction. Due to a lack of accurate, repeatable, individual methane measurements needed for breeding, indicators of methane production based on milk fatty acids have been proposed. The aim of the present study was to quantify the genetic variation for predicted methane yields. The milk fat composition of 1,905 first-lactation Dutch Holstein-Friesian cows was used to investigate 3 different predicted methane yields (g/kg of DMI): Methane1, Methane2, and Methane3. Methane1 was based on the milk fat proportions of C17:0anteiso, C18:1 rans-10+11, C18:1 cis-11, and C18:1 cis-13 (R(2)=0.73). Methane2 was based on C4:0, C18:0, C18:1 trans-10+11, and C18:1 cis-11 (R(2)=0.70). Methane3 was based on C4:0, C6:0, and C18:1 trans-10+11 (R(2)=0.63). Predicted methane yields were demonstrated to be heritable traits, with heritabilities between 0.12 and 0.44. Breeding can, thus, be used to decrease methane production predicted based on milk fatty acids.

  11. Bacteria isolated from Korean black raspberry vinegar with low biogenic amine production in wine.

    PubMed

    Song, Nho-Eul; Cho, Hyoun-Suk; Baik, Sang-Ho

    2016-01-01

    A high concentration of histamine, one of the biogenic amines (BAs) usually found in fermented foods, can cause undesirable physiological side effects in sensitive humans. The objective of this study is to isolate indigenous Acetobacter strains from naturally fermented Bokbunja vinegar in Korea with reduced histamine production during starter fermentation. Further, we examined its physiological and biochemical properties, including BA synthesis. The obtained strain MBA-77, identified as Acetobacter aceti by 16S rDNA homology and biochemical analysis and named A. aceti MBA-77. A. aceti MBA-77 showed optimal acidity % production at pH 5; the optimal temperature was 25°C. When we prepared and examined the BAs synthesis spectrum during the fermentation process, Bokbunja wine fermented with Saccharomyces cerevisiae showed that the histamine concentration increased from 2.72 of Bokbunja extract to 5.29mg/L and cadaverine and dopamine was decreased to 2.6 and 10.12mg/L, respectively. Bokbunja vinegar prepared by A. aceti MBA-77 as the starter, the histamine concentration of the vinegar preparation step was decreased up to 3.66mg/L from 5.29mg/L in the wine preparation step. To our knowledge, this is the first report to demonstrate acetic acid bacteria isolated from Bokbunja seed vinegar with low spectrum BA and would be useful for wellbeing vinegar preparation.

  12. Photochemistry of biogenic gases

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.

    1989-01-01

    The relationship between the biosphere and the atmosphere is examined, emphasizing the composition and photochemistry and chemistry of the troposphere and stratosphere. The reactions of oxygen, ozone, and hydroxyl are reviewed and the fate of the biogenic gases ammonia, methane, reduced sulfur species, reduced halogen species, carbon monoxide, nitric oxide, nitrous oxide, nitrogen, and carbon dioxide are described. A list is given of the concentration and sources of the various gases.

  13. Biogenic amine production by Lactococcus lactis subsp. cremoris strains in the model system of Dutch-type cheese.

    PubMed

    Flasarová, Radka; Pachlová, Vendula; Buňková, Leona; Menšíková, Anna; Georgová, Nikola; Dráb, Vladimír; Buňka, František

    2016-03-01

    The aim of this study was to compare the biogenic amine production of two starter strains of Lactococcus lactis subsp. cremoris (strains from the Culture Collection of Dairy Microorganisms - CCDM 824 and CCDM 946) with decarboxylase positive activity in a model system of Dutch-type cheese during a 90-day ripening period at 10°C. During ripening, biogenic amine and free amino acid content, microbiological characteristics and proximate chemical properties were observed. By the end of the ripening period, the putrescine content in both samples with the addition of the biogenic amine producing strain almost evened out and the concentration of putrescine was >800mg/kg. The amount of tyramine in the cheeses with the addition of the strain of CCDM 824 approached the limit of 400mg/kg by the end of ripening. In the cheeses with the addition of the strain of CCDM 946 it even exceeded 500mg/kg. In the control samples, the amount of biogenic amines was insignificant.

  14. Biogas crops grown in energy crop rotations: Linking chemical composition and methane production characteristics.

    PubMed

    Herrmann, Christiane; Idler, Christine; Heiermann, Monika

    2016-04-01

    Methane production characteristics and chemical composition of 405 silages from 43 different crop species were examined using uniform laboratory methods, with the aim to characterise a wide range of crop feedstocks from energy crop rotations and to identify main parameters that influence biomass quality for biogas production. Methane formation was analysed from chopped and over 90 days ensiled crop biomass in batch anaerobic digestion tests without further pre-treatment. Lignin content of crop biomass was found to be the most significant explanatory variable for specific methane yields while the methane content and methane production rates were mainly affected by the content of nitrogen-free extracts and neutral detergent fibre, respectively. The accumulation of butyric acid and alcohols during the ensiling process had significant impact on specific methane yields and methane contents of crop silages. It is proposed that products of silage fermentation should be considered when evaluating crop silages for biogas production.

  15. Production of Excited Atomic Hydrogen from Methane

    NASA Astrophysics Data System (ADS)

    Machacek, J. R.; Andrianarijaona, V. M.; Furst, J. E.; Gay, T. J.; Kilcoyne, A. L. D.; Landers, A. L.; McLaughlin, K. W.

    2009-05-01

    We have measured the production of Lyα and Hα fluorescence from atomic H for the photodissociation of CH4 by linearly-polarized photons with energies between 20 and 65 eV. Comparison between our Lyα relative cross section and that previously reported [1] show different peak height ratios. This also occurs in the Hα cross section when compared to previous data [2]. We do not observe as significant a drop in either cross section above 35 eV. Our measurements were taken with pressures two orders of magnitude lower than those used in ref. [1]. We present comparisons between data sets and a discussion of possible systematic effects. [1] H. Fukuzawa et al., J. Phys. B. 38, 565 (2005). [2] M. Kato et al., J. Phys. B. 35, 4383 (2002). Support provided by the NSF (Grant PHY-0653379), DOE (LBNL/ALS) and ANSTO (Access to Major Research Facilities Programme).

  16. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Buddy King

    2003-12-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the US have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the second year of a three-year endeavor being sponsored by maurer Technology, noble, and Anadarko Petroleum, in partnership with the DOE. The purpose of the project is to build on previous and ongoing R and D in the area of onshore hydrate deposition. They plan to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. They also plan to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope is to drill and core a well on Anadarko leases in FY 2003 and 2004. They are also using an on-site core analysis laboratory to determine some of the physical characteristics of the hydrates and surrounding rock. The well is being drilled from a new Anadarko Arctic Platform that will have minimal footprint and environmental impact. They hope to correlate geology, geophysics, logs, and drilling and production data to allow reservoir models to be calibrated. Ultimately, the goal is to form an objective technical and economic evaluation of reservoir potential in Alaska.

  17. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Buddy King

    2004-03-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the second year of a three-year endeavor being sponsored by Maurer Technology, Noble, and Anadarko Petroleum, in partnership with the DOE. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition. We plan to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. We also plan to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope is to drill and core a well on Anadarko leases in FY 2003 and 2004. We are also using an on-site core analysis laboratory to determine some of the physical characteristics of the hydrates and surrounding rock. The well is being drilled from a new Anadarko Arctic Platform that will have minimal footprint and environmental impact. We hope to correlate geology, geophysics, logs, and drilling and production data to allow reservoir models to be calibrated. Ultimately, our goal is to form an objective technical and economic evaluation of reservoir potential in Alaska.

  18. The influence of petroleum products on the methane fermentation process.

    PubMed

    Choromański, Paweł; Karwowska, Ewa; Łebkowska, Maria

    2016-01-15

    In this study the influence of the petroleum products: diesel fuel and spent engine oil on the sewage sludge digestion process and biogas production efficiency was investigated. Microbiological, chemical and enzymatic analyses were applied in the survey. It was revealed that the influence of the petroleum derivatives on the effectiveness of the methane fermentation of sewage sludge depends on the type of the petroleum product. Diesel fuel did not limit the biogas production and the methane concentration in the biogas, while spent engine oil significantly reduced the process efficacy. The changes in physical-chemical parameters, excluding COD, did not reflect the effect of the tested substances. The negative influence of petroleum products on individual bacterial groups was observed after 7 days of the process, while after 14 days probably some adaptive mechanisms appeared. The dehydrogenase activity assessment was the most relevant parameter to evaluate the effect of petroleum products contamination. Diesel fuel was probably used as a source of carbon and energy in the process, while the toxic influence was observed in case of spent engine oil.

  19. Methane production and methanogen levels in steers that differ in residual gain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methane gas released by cattle is a product of fermentation in the digestive tract. The two primary sites of methane fermentation in ruminants are the reticulum-rumen complex, and the cecum. Methane release from cattle represents a 2 to 12% loss of the energy intake. Reducing the proportion of fe...

  20. Biofilm-Forming Capacity in Biogenic Amine-Producing Bacteria Isolated from Dairy Products

    PubMed Central

    Diaz, Maria; Ladero, Victor; del Rio, Beatriz; Redruello, Begoña; Fernández, María; Martin, M. Cruz; Alvarez, Miguel A.

    2016-01-01

    Biofilms on the surface of food industry equipment are reservoirs of potentially food-contaminating bacteria—both spoilage and pathogenic. However, the capacity of biogenic amine (BA)-producers to form biofilms has remained largely unexamined. BAs are low molecular weight, biologically active compounds that in food can reach concentrations high enough to be a toxicological hazard. Fermented foods, especially some types of cheese, accumulate the highest BA concentrations of all. The present work examines the biofilm-forming capacity of 56 BA-producing strains belonging to three genera and 10 species (12 Enterococcus faecalis, 6 Enterococcus faecium, 6 Enterococcus durans, 1 Enterococcus hirae, 12 Lactococcus lactis, 7 Lactobacillus vaginalis, 2 Lactobacillus curvatus, 2 Lactobacillus brevis, 1 Lactobacillus reuteri, and 7 Lactobacillus parabuchneri), all isolated from dairy products. Strains of all the tested species - except for L. vaginalis—were able to produce biofilms on polystyrene and adhered to stainless steel. However, the biomass produced in biofilms was strain-dependent. These results suggest that biofilms may provide a route via which fermented foods can become contaminated by BA-producing microorganisms. PMID:27242675

  1. Control of Methane Production and Exchange in Northern Peatlands

    NASA Technical Reports Server (NTRS)

    Crill, Patrick

    1997-01-01

    This proposal has successfully supported studies that have developed unique long ten-n datasets of methane (CH4) emissions and carbon dioxide (CO2) exchange in order to quantify the controls on CH4 production and exchange especially the linkages to the carbon cycle in northern peatlands. The primary research site has been a small fen in southeastern New Hampshire where a unique multi-year data baseline of CH4 flux measurements was begun (with NASA funding) in 1989. The fen has also been instrumented for continuous hydrological and meteorological observations and year-round porewater sampling. Multiyear datasets of methane flux are very valuable and very rare. Datasets using the same sampling techniques at the same sites are the only way to assess the effect of the integrated ecosystem response to climatological variability. The research has had two basic objectives: 1. To quantify the effect of seasonal and interannual variability on CH4flux. 2. To examine process level controls on methane dynamics.

  2. Sorghums for methane production. Annual report, April 1984-March 1985

    SciTech Connect

    Hiler, E.A.; Miller, F.R.; Monk, R.L.; McBee, G.G.; Creelman, R.A.

    1985-06-01

    The objective of this research is to develop an integrated system for methane production utilizing high-energy sorghum as the feedstock. This report provides specifics of 2nd year research activities in the sorghums-for-methane production sponsored by Gas Research Institute and co-funded by Texas Agricultural Experiment Station. Researchers in the program include plant geneticists, sorghum physiologists, chemists, agronomists, ruminant physiologists, agricultural and systems engineers and agricultural economists. Major research emphases are genetic manipulation, physiology and production systems, harvesting, storage, processing and conversion systems, inhibitors, and economic and systems analyses. During the 2nd year, increased emphasis was placed on the storage, processing, and conversion aspects of the program. Because of the criticality of high efficiency conversion to the economic implementation of the system, considerable progress has been made in evaluating necessary parameters for harvesting, storage, and conversion. Emphasis has been placed on obtaining definitive data for a 2-stage leaching-bed, packed-bed digestion system. In the breeding and production program, much progress has been made in identifying and characterizing sorghums that will produce maximum biomass yields; for the high energy sorghums (designed for producing both food and energy) selections have been made for improved lodging resistance and height uniformity.

  3. Biogenic VOC and Climate

    NASA Astrophysics Data System (ADS)

    Guenther, A. B.

    2014-12-01

    Secondary organic aerosol (SOA) and ozone are short-lived contributors to radiative forcing that can drive relatively rapid changes in climate. They are not emitted into the atmosphere but are formed from precursors including biogenic volatile organic compounds (BVOC) that are emitted from terrestrial ecosystems. BVOC can also impact longer-lived climate-relevant compounds by acting as a sink for the oxidants that remove moderately reactive gases such as methane and by being a source of carbon dioxide. Emissions of BVOC are highly temperature sensitive, and some also respond to light, and so there is a potential feedback coupling between climate and BVOC emissions. Another potential feedback is associated with the water cycle since SOA can influence precipitation by serving as cloud condensation nuclei and because VOC emissions are sensitive to water availability. Anthropogenic air pollutants add to the complexity of this coupled system by enhancing the production of ozone and SOA from BVOC. The role of BVOC in the land-atmosphere-climate system and potential feedback couplings is conceptually clear but developing an accurate quantitative representation is challenging. Our current understanding of the role of BVOC in the climate system and potential feedback couplings will be presented and the major uncertainties will be discussed. Advances in observations for constraining models, including long-term measurements and recent multi-scale studies, will be presented and priorities for continued advances will be discussed.

  4. Seawater-based methane production from blue-green algae biomass by marine bacteria coculture

    SciTech Connect

    Matsunaga, T.; Izumida, H.

    1984-01-01

    Marine-enriched culture NKM 004 produced methane from various carbohydrates, but methane production was inhibited by sulfate and acetate accumulated in the medium. On the other hand, marine methanogenic bacterium NKM 006 produced methane from acetate and methyltrophic substrates, and methane production was not inhibited by sulfate. The mixture of NKM 004 and NKM 006 continuously produced methane from marine blue-green algae Dermocarpa species NKBG 102B at 54 ..mu..mol/L medium/h for 200 h and the dry weight of the algal biomass was decreased to 25% of the initial weight in the natural seawater. Conversion of algal carbohydrate (glucose equivalent) to methane was 65%. Results indicate that this system is promising for methane production based on seawater and solar energy.

  5. Carbon and hydrogen isotope composition and C-14 concentration in methane from sources and from the atmosphere: Implications for a global methane budget. Final report, 1 January-30 June 1991

    SciTech Connect

    Wahlen, M.

    1994-03-01

    The topics covered include the following: biogenic methane studies; forest soil methane uptake; rice field methane sources; atmospheric measurements; stratospheric samples; Antarctica; California; and Germany.

  6. Biogenic methane production in formation waters from a large gas field in the North Sea.

    PubMed

    Gray, Neil D; Sherry, Angela; Larter, Stephen R; Erdmann, Michael; Leyris, Juliette; Liengen, Turid; Beeder, Janiche; Head, Ian M

    2009-05-01

    Methanogenesis was investigated in formation waters from a North Sea oil rimmed gas accumulation containing biodegraded oil, which has not been subject to seawater injection. Activity and growth of hydrogenotrophic methanogens was measured but acetoclastic methanogenesis was not detected. Hydrogenotrophic methanogens showed activity between 40 and 80 degrees C with a temperature optimum (ca. 70 degrees C) consistent with in situ reservoir temperatures. They were also active over a broad salinity range, up to and consistent with the high salinity of the waters (90 g l(-1)). These findings suggest the methanogens are indigenous to the reservoir. The conversion of H(2) and CO(2) to CH(4) in methanogenic enrichments was enhanced by the addition of inorganic nutrients and was correlated with cell growth. Addition of yeast extract also stimulated methanogenesis. Archaeal 16S rRNA gene sequences recovered from enrichment cultures were closely related to Methanothermobacter spp. which have been identified in other high-temperature petroleum reservoirs. It has recently been suggested that methanogenic oil degradation may be a major factor in the development of the world's heavy oils and represent a significant and ongoing process in conventional deposits. Although an oil-degrading methanogenic consortium was not enriched from these samples the presence and activity of communities of fermentative bacteria and methanogenic archaea was demonstrated. Stimulation of methanogenesis by addition of nutrients suggests that in situ methanogenic biodegradation of oil could be harnessed to enhance recovery of stranded energy assets from such petroleum systems.

  7. Biogasification of water hyacinth and sludge for methane production

    SciTech Connect

    Chynoweth, D.P.; Biljetina, R.; Srivastava, V.J.; Hayes, T.D.

    1985-01-01

    Research is in progress to determine the technical and economic feasibility of treatment of domestic sewage using primary settling and water hyacinth ponds and conversion of the organic products of this treatment (primary sludge and hyacinth) to substitute natural gas. This paper describes the status of the conversion component of this program which is centered on anaerobic digestion of hyacinth/sludge blends to methane. The results of several experiments conducted successfully in a large-scale experimental test unit located at the hyacinth treatment facility at Walt Disney are presented. 11 refs., 5 figs., 4 tabs.

  8. DMS Sulphate and MSA as tracers of marine biogenic productivity in an Arctic snowpack

    NASA Astrophysics Data System (ADS)

    Wasiuta, V.; Norman, A.; Marshall, S.

    2007-12-01

    Sources, seasonal patterns, and spatial variations of snowpack sulphate of the Prince of Wales Icefield, Ellesmere Island were assessed using δ34S values along with major ion and MSA concentrations. Snowpack sulphate concentrations and δ34S values diminished with elevation and inland distance suggesting that the proximal North Water Polynya was the major sulphate source with additional sources affecting specific regions. Snowpack δ34S values in depth profile reflected seasonal cycles of marine biogenic, anthropogenic, and sea-salt aerosols with appreciable contributions of marine biogenic sulphate to virtually every depth horizon. A proximal April/May marine biogenic source was indicated, with DMS oxidation occurring near the marine boundary layer, and the possibility of additional oxidation at higher atmospheric levels. Depositional patterns of DMS sulphate and MSA indicate they were oxidized from DMS at different elevations in the atmosphere and that their deposition routes differed.

  9. Precessional control on ocean productivity in the Western Pacific Warm Pool for the last 400 kyr: Insight from biogenic magnetite

    NASA Astrophysics Data System (ADS)

    Yamazaki, Toshitsugu; Horiuchi, Kazuho

    2016-11-01

    Western Pacific Warm Pool plays a significant role in large-scale atmospheric circulation and global hydrology. We conducted an environmental magnetic study of two late Pleistocene sediment cores from the western equatorial Pacific Ocean offshore of New Guinea in order to better constrain climatic and oceanographic variability, particularly spatiotemporal ocean productivity variations. Magnetic property measurements and transmission electron microscopy reveal that the magnetic mineral assemblages in the studied sediments are a mixture of biogenic and terrigenous magnetite. Variations in the acid soluble sediment component, interpreted as carbonate content, and the proportion of biogenic to terrigenous magnetite estimated from the ratio of anhysteretic to saturation remanent magnetizations are in-phase with northern hemisphere summer insolation variations. We interpret that ocean productivity increased during insolation maxima, which induced higher populations of magnetotactic bacteria through a larger nutrient supply to the seafloor. This interpretation assumes that magnetotactic bacterial populations are greatest in sediments just below the seafloor. Precessional frequencies in magnetic mineral concentration variations are suppressed after correction for carbonate dilution, whereas cyclic changes with a ˜100 kyr periodicity remain in carbonate-free magnetic concentration variations. Glacial/interglacial changes in bottom water currents may have influenced transportation and deposition of magnetic minerals. We demonstrate the usefulness of magnetic proxies for paleoceanographic studies, particularly of biogenic magnetite proxies for estimating paleoproductivity variations.

  10. Enhanced methane production via repeated batch bioaugmentation pattern of enriched microbial consortia.

    PubMed

    Yang, Zhiman; Guo, Rongbo; Xu, Xiaohui; Wang, Lin; Dai, Meng

    2016-09-01

    Using batch and repeated batch cultivations, this study investigated the effects of bioaugmentation with enriched microbial consortia (named as EMC) on methane production from effluents of hydrogen-producing stage of potato slurry, as well as on the indigenous bacterial community. The results demonstrated that the improved methane production and shift of the indigenous bacterial community structure were dependent on the EMC/sludge ratio and bioaugmentation patterns. The methane yield and production rate in repeated batch bioaugmentation pattern of EMC were, respectively, average 15% and 10% higher than in one-time bioaugmentation pattern of EMC. DNA-sequencing approach showed that the enhanced methane production in the repeated batch bioaugmentation pattern of EMC mainly resulted from the enriched iron-reducing bacteria and the persistence of the introduced Syntrophomonas, which led to a rapid degradation of individual VFAs to methane. The findings contributed to understanding the correlation between the bioaugmentation of microbial consortia, community shift, and methane production.

  11. Calibration of Productivity Proxy Based on Fish Tooth Flux and Biogenic Barium in Pacific Deep-Sea Sediments

    NASA Astrophysics Data System (ADS)

    Vincent, K.

    2015-12-01

    Biological production is a key variable in paleoceanography, yet most measures reflect the detailed responses of specific biological communities—opal for biosiliceous producters, alkenones for some coccolithophorids, and percent carbonate for a heterogeneous mixture of calcareous phytoplankton and zooplankton, among others. We are developing a new method for extracting biogenic barite and fish teeth from deep-sea sediments and calibrating the fluxes of both components to satellite-derived ocean productivity. Both fish teeth and barite capture major components of biological production in the ocean. Teeth capture dynamics of high trophic level communities who depend upon lower level production in mostly short food chains. Barite reflects export flux of marine particulate carbon, and hence records the major producers of marine snow. Our methods digest sediments to remove carbonates, and concentrate teeth with heavy liquid separation. Barite is also concentrated by acid dissolution of carbonate, but then we dissolve barite, collect the sulfate in solution, and re-precipitate barite rather than use the time consuming and dangerous methods that are currently the industry standard. Counting the number of fish teeth present in the sample and extracting the amount of biogenic barium will discover two different proxies of productivity. The sample sites range throughout the Pacific Ocean, giving a wide scope of variability along with satellite productivity levels. The results between the amount of fish teeth as well as the biogenic barite levels will hopefully be at a similar level, indicating that this method is a new tried and true proxy for productivity in the future.

  12. Modeling methane emissions by cattle production systems in Mexico

    NASA Astrophysics Data System (ADS)

    Castelan-Ortega, O. A.; Ku Vera, J.; Molina, L. T.

    2013-12-01

    Methane emissions from livestock is one of the largest sources of methane in Mexico. The purpose of the present paper is to provide a realistic estimate of the national inventory of methane produced by the enteric fermentation of cattle, based on an integrated simulation model, and to provide estimates of CH4 produced by cattle fed typical diets from the tropical and temperate climates of Mexico. The Mexican cattle population of 23.3 million heads was divided in two groups. The first group (7.8 million heads), represents cattle of the tropical climate regions. The second group (15.5 million heads), are the cattle in the temperate climate regions. This approach allows incorporating the effect of diet on CH4 production into the analysis because the quality of forages is lower in the tropics than in temperate regions. Cattle population in every group was subdivided into two categories: cows (COW) and other type of cattle (OTHE), which included calves, heifers, steers and bulls. The daily CH4 production by each category of animal along an average production cycle of 365 days was simulated, instead of using a default emission factor as in Tier 1 approach. Daily milk yield, live weight changes associated with the lactation, and dry matter intake, were simulated for the entire production cycle. The Moe and Tyrrell (1979) model was used to simulate CH4 production for the COW category, the linear model of Mills et al. (2003) for the OTHE category in temperate regions and the Kurihara et al. (1999) model for the OTHE category in the tropical regions as it has been developed for cattle fed tropical diets. All models were integrated with a cow submodel to form an Integrated Simulation Model (ISM). The AFRC (1993) equations and the lactation curve model of Morant and Gnanasakthy (1989) were used to construct the cow submodel. The ISM simulates on a daily basis the CH4 production, milk yield, live weight changes associated with lactation and dry matter intake. The total daily CH

  13. Biogenic mineral production by a novel arsenic-metabolizing thermophilic bacterium from the Alvord Basin, OR

    SciTech Connect

    Ledbetter, Rhesa N.; Connon, Stephanie A.; Neal, Andrew L.; Dohnalkova, Alice; Magnuson, Timothy S.

    2007-09-01

    The Alvord Basin in southeast Oregon, USA contains a variety of hydrothermal features, which have never been microbiologically characterized. Murky Pot (61°C, pH 7.1) was selected for this study. Sampling of Murky Pot led to the isolation of a novel arsenic-metabolizing organism (YeAs), which produces an arsenic sulfide mineral known as beta-realgar, a mineral that has not previously been observed as a product of bacterial arsenic metabolism. Our goal was to characterize and identify YeAs based on its phylogenetic, physiological, and morphological characteristics. 16S rRNA gene analysis revealed that YeAs has 98.9% sequence similarity to that of Thermobrachium celere. YeAs was grown on a freshwater medium and could utilize a variety of organic substrates, particularly carbohydrates and organic acids. Optimum growth of the organism was seen at 55ºC, but showed growth at a range of 37° to 75°C. No growth was observed when YeAs was grown under aerobic conditions. Microscopic examination revealed Gram-indeterminate, non-spore forming, rod shaped cells. Electron microscopy and elemental analysis revealed significant arsenic sulfide mineralization of cell walls, and extracellular particulate deposition of arsenic sulfide minerals. YeAs showed no detectable respiratory arsenate reductase; however, the organism did display significant detoxification arsenate reductase activity. The phylogenetic, physiological, and morphological characteristics of YeAs demonstrate that it is an anaerobic, moderately thermophilic, arsenic-reducing bacterium. This organism and its associated metabolism could have major implications in the search for innovative methods for arsenic waste management and in the search for novel biogenic signatures.

  14. Equations of state of detonation products: ammonia and methane

    NASA Astrophysics Data System (ADS)

    Lang, John; Dattelbaum, Dana; Goodwin, Peter; Garcia, Daniel; Coe, Joshua; Leiding, Jeffery; Gibson, Lloyd; Bartram, Brian

    2015-06-01

    Ammonia (NH3) and methane (CH4) are two principal product gases resulting from explosives detonation, and the decomposition of other organic materials under shockwave loading (such as foams). Accurate thermodynamic descriptions of these gases are important for understanding the detonation performance of high explosives. However, shock compression data often do not exist for molecular species in the dense gas phase, and are limited in the fluid phase. Here, we present equation of state measurements of elevated initial density ammonia and methane gases dynamically compressed in gas-gun driven plate impact experiments. Pressure and density of the shocked gases on the principal Hugoniot were determined from direct particle velocity and shock wave velocity measurements recorded using optical velocimetry (Photonic Doppler velocimetry (PDV) and VISAR (velocity interferometer system for any reflector)). Streak spectroscopy and 5-color pyrometry were further used to measure the emission from the shocked gases, from which the temperatures of the shocked gases were estimated. Up to 0.07 GPa, ammonia was not observed to ionize, with temperature remaining below 7000 K. These results provide quantitative measurements of the Hugoniot locus for improving equations of state models of detonation products.

  15. Methane production by large iron meteorite impacts on early Earth

    NASA Astrophysics Data System (ADS)

    Sekine, Yasuhito; Sugita, Seiji; Kadono, Toshihiko; Matsui, Takafumi

    2003-07-01

    The continuous existence of life on the Earth is thought to have begun around 4 Ga, which is near the end of the heavy bombardment period. Impacts of asteroids and comets may have produced and delivered organic matter on the Hadean Earth. However, the nature of those processes has not been understood well yet. In this paper, we propose a new process of organic synthesis induced by asteroid impacts. We consider the effect of impact vapor condensates reentering the Earth's early atmosphere. Vapor condensates produced by a large-scale impact are dispersed around the globe and reenter the atmosphere at very high speed. The reentering condensates are heated and decelerated by the friction with the atmosphere and form a ``hot condensate layer'' around the globe. We calculate the temperature and atmospheric pressure of the hot condensate layer as a function of time. A Fischer-Tropsch reaction on the surface of the reentering iron and nickel condensates will lead to efficient methane production. The reaction rate of Fischer-Tropsch catalysis is estimated based on a kinetic model. Calculation results indicate that the amount of methane produced by the impact of an iron meteorite with a diameter of 10 km at 15 km sec-1 of velocity reaches ~1012-1013 kg. Some of the methane formed by this process is photodissociated to HCN and organic aerosols. The amount of the resulting HCN is estimated to be ~1010-1012 kg. This is 103-104 times the preimpact inventory of HCN on the Earth, which is maintained by UV radiation and electric discharge in a mildly reducing (i.e., CO-CO2 dominant) atmosphere. Such an episodic increase in the organic inventory on the surface of the early Earth may have played an important role in the origin of life.

  16. Exponential model describing methane production kinetics in batch anaerobic digestion: a tool for evaluation of biochemical methane potential assays.

    PubMed

    Brulé, Mathieu; Oechsner, Hans; Jungbluth, Thomas

    2014-09-01

    Biochemical methane potential assays, usually run in batch mode, are performed by numerous laboratories to characterize the anaerobic degradability of biogas substrates such as energy crops, agricultural residues, and organic wastes. Unfortunately, the data obtained from these assays lacks common, universal bases for comparison, because standard protocols did not diffuse to the entire scientific community. Results are usually provided as final values of the methane yields of substrates. However, methane production curves generated in these assays also provide useful information about substrate degradation kinetics, which is rarely exploited. A basic understanding of the kinetics of the biogas process may be a first step towards a convergence of the assay methodologies on an international level. Following this assumption, a modeling toolbox containing an exponential model adjusted with a simple data-fitting method has been developed. This model should allow (a) quality control of the assays according to the goodness of fit of the model onto data series generated from the digestion of standard substrates, (b) interpretation of substrate degradation kinetics, and (c) estimate of the ultimate methane yield at infinite time. The exponential model is based on two assumptions: (a) the biogas process is a two-step reaction yielding VFA as intermediate products, and methane as the final product, and (b) the digestible substrate can be divided into a rapidly degradable and a slowly degradable fraction.

  17. Basic Study on Production Well Integrity for Methane Hydrate Development

    NASA Astrophysics Data System (ADS)

    Kakumoto, M.; Yoneda, J.; Katagiri, J.; Tenma, N.; Aoki, K.

    2014-12-01

    Methane Hydrate (MH) exist as an ice-like crystal under low-temperature and high-pressure condition, and it has gathering attention as a non-conventional natural gas resource. Depressurization method is a method to reduce the bottom hole pressure by submersible pump lowering water level in the production well, and gas and water is recovered by MH dissociation at the in situ. During the depressurization operation, consolidation and deformation of sediment occurs because of increase of effective stress by depressurization and changes in the soil structure by MH dissociation. Then consolidation and deformation of sediment makes negative friction between the production well and sediment, and large stress is occur in casing. Therefore there is concern that it may cause compression failure and shear failure of the production well. For safe MH development, it is necessary to grasp the deformation and stress vicinity of the production well. At first, we conducted push-out test to get friction strength between the different materials simulated the well and sediment. And we have done numerical analysis for integrity using by these data. The results of numerical analysis showed that the large deformation of sediment occur around the depressurization zone, and for the well, the large tensile stress in the vertical direction occur the upper vicinity of the depressurization zone.This study was financially supported by the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) planned by Ministry of Economy, Trade and Industry (METI). The authors thank the entire personnel related to MH21 Research Consortium.

  18. Hydrogen production from methane using oxygen-permeable ceramic membranes

    NASA Astrophysics Data System (ADS)

    Faraji, Sedigheh

    Non-porous ceramic membranes with mixed ionic and electronic conductivity have received significant interest in membrane reactor systems for the conversion of methane and higher hydrocarbons to higher value products like hydrogen. However, hydrogen generation by this method has not yet been commercialized and suffers from low membrane stability, low membrane oxygen flux, high membrane fabrication costs, and high reaction temperature requirements. In this dissertation, hydrogen production from methane on two different types of ceramic membranes (dense SFC and BSCF) has been investigated. The focus of this research was on the effects of different parameters to improve hydrogen production in a membrane reactor. These parameters included operating temperature, type of catalyst, membrane material, membrane thickness, membrane preparation pH, and feed ratio. The role of the membrane in the conversion of methane and the interaction with a Pt/CeZrO2 catalyst has been studied. Pulse studies of reactants and products over physical mixtures of crushed membrane material and catalyst have clearly demonstrated that a synergy exists between the membrane and the catalyst under reaction conditions. The degree of catalyst/membrane interaction strongly impacts the conversion of methane and the catalyst performance. During thermogravimetric analysis, the onset temperature of oxygen release for BSCF was observed to be lower than that for SFC while the amount of oxygen release was significantly greater. Pulse injections of CO2 over crushed membranes at 800°C have shown more CO2 dissociation on the BSCF membrane than the SFC membrane, resulting in higher CO formation on the BSCF membrane. Similar to the CO2 pulses, when CO was injected on the samples at 800°C, CO2 production was higher on BSCF than SFC. It was found that hydrogen consumption on BSCF particles is 24 times higher than that on SFC particles. Furthermore, Raman spectroscopy and temperature programmed desorption studies of

  19. Effect of natural zeolite on methane production for anaerobic digestion of ammonium rich organic sludge.

    PubMed

    Tada, Chika; Yang, Yingnan; Hanaoka, Toshiaki; Sonoda, Akinari; Ooi, Kenta; Sawayama, Shigeki

    2005-03-01

    The effect of an inorganic additive on the methane production from NH(4+)-rich organic sludge during anaerobic digestion was investigated using different kinds of inorganic adsorbent zeolites (mordenite, clinoptilolite, zeolite 3A, zeolite 4A), clay mineral (vermiculite), and manganese oxides (hollandite, birnessite). The additions of inorganic materials resulted in significant NH4+ removals from the natural organic sludge ([NH4+]=1, 150 mg N/l), except for the H-type zeolite 3A and birnessite. However, an enhanced methane production was only achieved using natural mordenite. Natural mordenite also enhanced the methane production from the sludge with a markedly high NH4+ concentration (4500 mg N/l) during anaerobic digestion. Chemical analyses of the sludge after the digestion showed considerable increases in the Ca2+ and Mg2+ concentrations in the presence of natural mordenite, but not with synthetic zeolite 3A. The effect of Ca2+ or Mg2+ addition on the methane production was studied using Na(+)-exchanges mordenite and Ca2+ or Mg(2+)-enriched sludge. The simultaneous addition of Ca2+ ions and Na(+)-exchanged mordenite enhanced the methane production; the amount of produced methane was about three times greater than that using only the Na(+)-exchanged mordenite. In addition, comparing the methane production by the addition of natural mordenite or Ca2+ ions, the methane production with natural mordenite was about 1.7 times higher than that with only Ca2+ ions. The addition of 5% and 10% natural mordenite were suitable condition for obtaining a high methane production. These results indicated that the Ca2+ ions, which are released from natural mordenite by a Ca2+/NH4+ exchange, enhanced the methane production of the organic waste at a high NH4+ concentration. Natural mordenite has a synergistic effect on the Ca2+ supply as well on the NH4+ removal during anaerobic digestion, which is effective for the mitigation of NH4+ inhibition against methane production.

  20. Stimulation of commercial coal seam methane production aimed at improving mining technology

    NASA Astrophysics Data System (ADS)

    Shubina, E. A.; Lukyanov, V. G.

    2016-09-01

    The relevance of the current research is due to the urgent need to revise the existing normative bases and procedures involved in intensive development of coal-methane deposits and commercial production of coal seam methane. The article presents the analysis of data on coal production volume and amount of methane emitted into the atmosphere in Kuzbass. There is a need to develop the exploration techniques that would allow implementing pre-mining gas drainage of coal seams and provide the companies with the guidance on coal seam methane drainage in very gassy coal mines. Commercial production of methane should become an integral part of economy and energy balance of the Russian Federation, which, in its turn, would enhance environmental protection due to reducing methane emissions, the largest source of greenhouse effect.

  1. Methane production from glycolate excreting algae as a new concept in the production of biofuels.

    PubMed

    Günther, Anja; Jakob, Torsten; Goss, Reimund; König, Swetlana; Spindler, Daniel; Räbiger, Norbert; John, Saskia; Heithoff, Susanne; Fresewinkel, Mark; Posten, Clemens; Wilhelm, Christian

    2012-10-01

    It is the aim of the present work to introduce a new concept for methane production by the interaction of a glycolate-excreting alga (Chlamydomonas reinhardtii) and methanogenic microbes operating in separate compartments within one photobioreactor. This approach requires a minimum number of metabolic steps to convert light energy to methane thereby reducing the energetic and financial costs of biomass formation, harvest and refinement. In this feasibility study it is shown that the physiological limitations for sustained glycolate production can be circumvented by the use of C. reinhardtii mutants whose carbon concentrating mechanisms or glycolate dehydrogenase are suppressed. The results also demonstrate that methanogenic microbes are able to thrive on glycolate as single carbon source for a long time period, delivering biogas composed of CO(2)/methane with only very minor contamination.

  2. Methane production, emission and possible control measures in the rice agriculture

    NASA Astrophysics Data System (ADS)

    Wang, Mingxing; Shangguan, Xingjian; Shen, Renxing; Reiner, Wassmann; Wolfgang, Seiler

    1993-09-01

    In the rice field methane is produced in the soil layer with depths of 2 25 cm. The vertical profile of methane production rate in the paddy soil during the water covering period differs from that in the paddy soil in dry phase. Only a small part, about 30%, of the produced methane is emitted to the atmosphere through rice plant, air bubbles, and molecular diffusion. Therefore, the methane emission rate from the rice field depends not only on the methane production rate in the soil, but also on the transport efficiency of the rice plant, air bubble formation that in turn depends on the production rate, and molecular diffusion. Field measurements show that methane emission rates from a particular rice field have very large diurnal, seasonal and interannual variations, which are related to soil characteristics, water regime, farming procedure, local climate, and rice growing activities. The relationship between the methane emission rate and the above mentioned factors is very complicated. The emission rates from different rice fields differ greatly not only in the absolute value, but also in the temporal variation patterns. Methane emission rate from the rice field may be significantly reduced by scientific management of fertilizer and irrigation. While the use of SO{4/2-} containing fertilizer and fermented organic fertilizer may reduce the methane emission significantly, the most promising measure for reducing methane emission from rice field is the frequent drainage irrigation procedure.

  3. Factors affecting methane production and mitigation in ruminants.

    PubMed

    Shibata, Masaki; Terada, Fuminori

    2010-02-01

    Methane (CH(4)) is the second most important greenhouse gas (GHG) and that emitted from enteric fermentation in livestock is the single largest source of emissions in Japan. Many factors influence ruminant CH(4) production, including level of intake, type and quality of feeds and environmental temperature. The objectives of this review are to identify the factors affecting CH(4) production in ruminants, to examine technologies for the mitigation of CH(4) emissions from ruminants, and to identify areas requiring further research. The following equation for CH(4) prediction was formulated using only dry matter intake (DMI) and has been adopted in Japan to estimate emissions from ruminant livestock for the National GHG Inventory Report: Y = -17.766 + 42.793X - 0.849X(2), where Y is CH(4) production (L/day) and X is DMI (kg/day). Technologies for the mitigation of CH(4) emissions from ruminants include increasing productivity by improving nutritional management, the manipulation of ruminal fermentation by changing feed composition, the addition of CH(4) inhibitors, and defaunation. Considering the importance of ruminant livestock, it is essential to establish economically feasible ways of reducing ruminant CH(4) production while improving productivity; it is therefore critical to conduct a full system analysis to select the best combination of approaches or new technologies to be applied under long-term field conditions.

  4. Study of the effect of biogenic VOC emissions on regional ozone production and the implications for VOC or NO{sub x} control

    SciTech Connect

    Stockwell, W.R.; Kuhn, M.

    1998-12-31

    A key question for the development of air pollution control strategies is whether to reduce nitrogen oxides (NO{sub x}) or volatile organic compound (VOC) emissions. Significant levels of biogenic VOC emissions may greatly limit the effectiveness of VOC control strategies. Concerns have been raised because for many cities it has been suggested that biogenic emissions are a dominate source of VOCs. Biogenic emissions would be expected to contribute an even larger fraction of the VOC emissions on the regional scale than within urban areas. The authors used a new atmospheric chemistry mechanism, the Regional Atmospheric Chemistry Mechanism (RACM), to perform ozone reactivity calculations to investigate the effects of biogenic emissions on the production of photooxidants in the atmosphere. The results show that incremental reactivity of isoprene is about the same as xylene and that the incremental reactivities of d-limonene and a-pinene are near those of toluene.

  5. Biogenic amines at a low level of evolution: Production, functions and regulation in the unicellular Tetrahymena.

    PubMed

    Csaba, György

    2015-06-01

    The unicellular eukaryote Tetrahymena synthesize, store and secrete biogenic amines (histamine, serotonin, epinephrine, dopamine, melatonin) and also can take up amines from the milieu. It also has (G-protein-coupled) receptors (binding sites) for these amines as well, as second messengers. The factors infuencing the mentioned processes are shown. For certain amines the genes and the coded enzymes are demonstrated. The amines influence phagocytosis, cell division, ciliary regeneration, glucose metabolism and chemotaxis. There are interhormone actions between the amines, and between the amines and other hormones produced by Tetrahymena. The critical review discusses the role of amines in the early stages of evolution and compares this to their functions in mammals. It tries to give answer how and why biogenic amines were selected to hormones, and why new functions formed for them in higher ranked animals, preserving also the ancient ones.

  6. Temperature regulates methane production through the function centralization of microbial community in anaerobic digestion.

    PubMed

    Lin, Qiang; De Vrieze, Jo; He, Guihua; Li, Xiangzhen; Li, Jiabao

    2016-09-01

    Temperature is crucial for the performance of anaerobic digestion process. In this study of anaerobic digestion of swine manure, the relationship between the microbial gene expression and methane production at different temperatures (25-55°C) was revealed through metatranscriptomic analysis. Daily methane production and total biogas production increased with temperature up to 50°C, but decreased at 55°C. The functional gene expression showed great variation at different temperatures. The function centralization (opposite to alpha-diversity), assessed by the least proportions of functional pathways contributing for at least 50% of total reads positively correlated to methane production. Temperature regulated methane production probably through reducing the diversity of functional pathways, but enhancing central functional pathways, so that most of cellular activities and resource were invested in methanogenesis and related pathways, enhancing the efficiency of conversion of substrates to methane. This research demonstrated the importance of function centralization for efficient system functioning.

  7. Production of Methanol from Methane by Encapsulated Methylosinus sporium.

    PubMed

    Patel, Sanjay K S; Jeong, Jae-Hoon; Mehariya, Sanjeet; Otari, Sachin V; Madan, Bharat; Haw, Jung Rim; Lee, Jung-Kul; Zhang, Liaoyuan; Kim, In-Won

    2016-12-28

    Massive reserves of methane (CH₄) remain unexplored as a feedstock for the production of liquid fuels and chemicals, mainly because of the lack of economically suitable and sustainable strategies for selective oxidation of CH₄ to methanol. The present study demonstrates the bioconversion of CH₄ to methanol mediated by Type I methanotrophs, such as Methylomicrobium album and Methylomicrobium alcaliphilum. Furthermore, immobilization of a Type II methanotroph, Methylosinus sporium, was carried out using different encapsulation methods, employing sodium-alginate (Na-alginate) and silica gel. The encapsulated cells demonstrated higher stability for methanol production. The optimal pH, temperature, and agitation rate were determined to be pH 7.0, 30°C, and 175 rpm, respectively, using inoculum (1.5 mg of dry cell mass/ml) and 20% of CH₄ as a feed. Under these conditions, maximum methanol production (3.43 and 3.73 mM) by the encapsulated cells was recorded. Even after six cycles of reuse, the Na-alginate and silica gel encapsulated cells retained 61.8% and 51.6% of their initial efficiency for methanol production, respectively, in comparison with the efficiency of 11.5% observed in the case of free cells. These results suggest that encapsulation of methanotrophs is a promising approach to improve the stability of methanol production.

  8. Methods for Detecting Microbial Methane Production and Consumption by Gas Chromatography

    PubMed Central

    Aldridge, Jared T.; Catlett, Jennie L.; Smith, Megan L.; Buan, Nicole R.

    2016-01-01

    Methane is an energy-dense fuel but is also a greenhouse gas 25 times more detrimental to the environment than CO2. Methane can be produced abiotically by serpentinization, chemically by Sabatier or Fisher-Tropsh chemistry, or biotically by microbes (Berndt et al., 1996; Horita and Berndt, 1999; Dry, 2002; Wolfe, 1982; Thauer, 1998; Metcalf et al., 2002). Methanogens are anaerobic archaea that grow by producing methane gas as a metabolic byproduct (Wolfe, 1982; Thauer, 1998). Our lab has developed and optimized three different gas chromatograph-utilizing assays to characterize methanogen metabolism (Catlett et al., 2015). Here we describe the end point and kinetic assays that can be used to measure methane production by methanogens or methane consumption by methanotrophic microbes. The protocols can be used for measuring methane production or consumption by microbial pure cultures or by enrichment cultures. PMID:27559541

  9. [Sources of Methane in the Boreal Region

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In determining the global methane budget the sources of methane must be balanced with the sinks and atmospheric inventory. The approximate contribution of the different methane sources to the budget has been establish showing the major terrestrial inputs as rice, wetlands, bogs, fens, and tundra. Measurements and modeling of production in these sources suggest that temperature, water table height and saturation along with substratum composition are important in controlling methane production and emission. The isotopic budget of 13 C and D/H in methane can be used as a tool to clarify the global budget. This approach has achieved success at constraining the inputs. Studies using the isotopic approach place constraints on global methane production from different sources. Also, the relation between the two biogenic production pathways, acetate fermentation and CO2 reduction, and the effect of substratum composition can be made using isotope measurements shows the relation between the different biogenic, thermogenic and anthropogenic sources of methane as a function of the carbon and hydrogen isotope values for each source and the atmosphere, tropospheric composition. Methane emissions from ponds and fens are a significant source in the methane budget of the boreal region. An initial study in 1993 and 1994 on the isotopic composition of this methane source and the isotopic composition in relation to oxidation of methane at the sediment surface of the ponds or fen was conducted as part of our BOREAS project. The isotopic composition of methane emitted by saturated anoxic sediment is dependent on the sediment composition and geochemistry, but will be influenced by in situ oxidation, in part, a function of rooted plant activity. The influence of oxidation mediated by rooted plant activities on the isotopic composition of methane is not well known and will depend on the plant type, sediment temperature, and numerous other variables. Information on this isotopic composition

  10. Evidence for methane production by the marine algae Emiliania huxleyi

    NASA Astrophysics Data System (ADS)

    Lenhart, Katharina; Klintzsch, Thomas; Langer, Gerald; Nehrke, Gernot; Bunge, Michael; Schnell, Sylvia; Keppler, Frank

    2016-06-01

    Methane (CH4), an important greenhouse gas that affects radiation balance and consequently the earth's climate, still has uncertainties in its sinks and sources. The world's oceans are considered to be a source of CH4 to the atmosphere, although the biogeochemical processes involved in its formation are not fully understood. Several recent studies provided strong evidence of CH4 production in oxic marine and freshwaters, but its source is still a topic of debate. Studies of CH4 dynamics in surface waters of oceans and large lakes have concluded that pelagic CH4 supersaturation cannot be sustained either by lateral inputs from littoral or benthic inputs alone. However, regional and temporal oversaturation of surface waters occurs frequently. This comprises the observation of a CH4 oversaturating state within the surface mixed layer, sometimes also termed the "oceanic methane paradox". In this study we considered marine algae as a possible direct source of CH4. Therefore, the coccolithophore Emiliania huxleyi was grown under controlled laboratory conditions and supplemented with two 13C-labeled carbon substrates, namely bicarbonate and a position-specific 13C-labeled methionine (R-S-13CH3). The CH4 production was 0.7 µg particular organic carbon (POC) g-1 d-1, or 30 ng g-1 POC h-1. After supplementation of the cultures with the 13C-labeled substrate, the isotope label was observed in headspace CH4. Moreover, the absence of methanogenic archaea within the algal culture and the oxic conditions during CH4 formation suggest that the widespread marine algae Emiliania huxleyi might contribute to the observed spatially and temporally restricted CH4 oversaturation in ocean surface waters.

  11. Predicted growth of world urban food waste and methane production.

    PubMed

    Adhikari, Bijaya K; Barrington, Suzelle; Martinez, José

    2006-10-01

    Landfill gas emissions are one of the largest anthropogenic sources of methane especially because of food waste (FW). To prevent these emissions growing with world population, future FW best management practices need to be evaluated. The objective of this paper was therefore to predict FW production for 2025 if present management practices are maintained, and then, to compare the impact of scenario 1: encouraging people to stay in rural areas and composting 75% of their FW, and; of scenario 2, where in addition to scenario 1, composting or anaerobically digesting 75% of urban FW (UFW). A relationship was established between per capita gross domestic product (GDP) and the population percentage living in urban areas (%UP), as well as production of municipal solid waste (MSW) and UFW. With estimated GDP and population growth per country, %UP and production of MSW and UFW could be predicted for 2025. A relatively accurate (R(2) > 0.85) correlation was found between GDP and %UP, and between GDP and mass of MSW and FW produced. On a global scale, MSW and UFW productions were predicted to increase by 51 and 44%, respectively, from 2005 to 2025. During the same period, and because of its expected economic development, Asia was predicted to experience the largest increase in UFW production, of 278 to 416 Gkg. If present MSW management trends are maintained, landfilled UFW was predicted to increase world CH4 emissions from 34 to 48 Gkg and the landfill share of global anthropogenic emissions from 8 to 10%. In comparison with maintaining present FW management practices, scenario 1 can lower UFW production by 30% and maintain the landfill share of the global anthropogenic emissions at 8%. With scenario 2, the landfill share of global anthropogenic emissions could be further reduced from 8 to 6% and leachate production could be reduced by 40%.

  12. Diverse patterns of ocean export productivity change across the Cretaceous-Paleogene boundary: New insights from biogenic barium

    NASA Astrophysics Data System (ADS)

    Hull, Pincelli M.; Norris, Richard D.

    2011-09-01

    One of the best-studied aspects of the K-Pg mass extinction is the decline and subsequent recovery of open ocean export productivity (e.g., the flux of organic matter from the surface to deep ocean). Some export proxies, including surface-to-deep water δ13C gradients and carbonate sedimentation rates, indicate a global decline in export productivity triggered by the extinction. In contrast, benthic foraminiferal and other geochemical productivity proxies suggest spatially and temporally heterogeneous K-Pg boundary effects. Here we address these conflicting export productivity patterns using new and compiled measurements of biogenic barium. Unlike a previous synthesis, we find that the boundary effect on export productivity and the timing of recovery varied considerably between different oceanic sites. The northeast and southwest Atlantic, Southern Ocean, and Indian Ocean records saw export production plummet and remain depressed for 350 thousand to 2 million years. Biogenic barium and other proxies in the central Pacific and some upwelling or neritic Atlantic sites indicate the opposite, with proxies recording either no change or increased export production in the early Paleocene. Our results suggest that widespread declines in surface-to-deep ocean δ13C do not record a global decrease in export productivity. Rather, independent proxies, including barium and other geochemical proxies, and benthic community structure, indicate that some regions were characterized by maintained or rapidly recovered organic flux from the surface ocean to the deep seafloor, while other regions had profound reductions in export productivity that persisted long into the Paleocene.

  13. Improved methane production from brown algae under high salinity by fed-batch acclimation.

    PubMed

    Miura, Toyokazu; Kita, Akihisa; Okamura, Yoshiko; Aki, Tsunehiro; Matsumura, Yukihiko; Tajima, Takahisa; Kato, Junichi; Nakashimada, Yutaka

    2015-01-01

    Here, a methanogenic microbial community was developed from marine sediments to have improved methane productivity from brown algae under high salinity. Fed-batch cultivation was conducted by adding dry seaweed at 1wt% total solid (TS) based on the liquid weight of the NaCl-containing sediment per round of cultivation. The methane production rate and level of salinity increased 8-fold and 1.6-fold, respectively, at the 10th round of cultivation. Moreover, the rate of methane production remained high, even at the 10th round of cultivation, with accumulation of salts derived from 10wt% TS of seaweed. The salinity of the 10th-round culture was equivalent to 5% NaCl. The improved methane production was attributed to enhanced acetoclastic methanogenesis because acetate became rapidly converted to methane during cultivation. The family Fusobacteriaceae and the genus Methanosaeta, the acetoclastic methanogen, predominated in bacteria and archaea, respectively, after the cultivation.

  14. Methane and Hydrogen Production from Anaerobic Fermentation of Municipal Solid Wastes

    NASA Astrophysics Data System (ADS)

    Kobayashi, Takuro; Lee, Dong-Yeol; Xu, Kaiqin; Li, Yu-You; Inamori, Yuhei

    Methane and hydrogen production was investigated in batch experiments of thermophilic methane and hydrogen fermentation, using domestic garbage and food processing waste classified by fat/carbohydrate balance as a base material. Methane production per unit of VS added was significantly positively correlated with fat content and negatively correlated with carbohydrate content in the substrate, and the average value of the methane production per unit of VS added from fat-rich materials was twice as large as that from carbohydrate-rich materials. By contrast, hydrogen production per unit of VS added was significantly positively correlated with carbohydrate content and negatively correlated with fat content. Principal component analysis using the results obtained in this study enable an evaluation of substrates for methane and hydrogen fermentation based on nutrient composition.

  15. Analysis of biogenic amines in northern and southern European sausages and role of flora in amine production.

    PubMed

    Ansorena, D; Montel, M C; Rokka, M; Talon, R; Eerola, S; Rizzo, A; Raemaekers, M; Demeyer, D

    2002-06-01

    The biogenic amine contents, microbial counts and flora producing amines were investigated in four types of fermented sausages. Southern type European sausages (Italian and Belgian) showed higher tyramine and phenylethylamine values than northern type ones (Norwegian and Belgian). The spontaneous non-starter lactic acid bacteria could be responsible for the production of these amines in the Italian products, and the cocci Gram positive in the Belgian South ones. The Norwegian sausages showed the lowest total amine content of those studied. The two Belgian types were characterised by the highest putrescine contents, associated with high counts of Enterococcus. The production of amines in vitro by the starter cultures used in the manufacture of the sausages revealed that none of the Lactobacillus species produced any amines and only Kocuria varians and Staphylococcus carnosus showed phenylethylamine and tryptamine production. High correlations were found between the content of putrescine, histamine and cadaverine.

  16. Methane production in sediments of small tundra ponds during winter

    NASA Astrophysics Data System (ADS)

    Macrae, M. L.; Fishback, L.; Bourbonniere, R. A.; Duguay, C. R.; Soliman, A. S.

    2011-12-01

    Shallow tundra ponds in the Churchill region of the Hudson Bay Lowlands (HBL) store large quantities of organic material in the form of sediments. Organic sediments in ponds and wetlands have been identified as a source of atmospheric methane (CH4) during the summer season in many landscapes. However, less is known about CH4 production and emission during the winter months, following the formation of an ice layer on the water surface. Unfrozen sediments may continue to produce methane (CH4) during this time, which may become trapped in the ponds beneath the ice layer. This occurrence has been identified in some regions through the sampling and analysis of CH4 bubbles frozen in lake ice. The goal of this project is to examine the potential for the production and trapping of CH4 in ponds beneath the pond ice (water/ice and sediment profiles) in the Churchill region of the HBL. Thermistor and gas sampling arrays were installed in the water and sediments of two ponds. Gas samples were collected at 1-4 week intervals at the sediment-water interface and at 0-15cm and 20-35 cm depth. Results show that sediments are indeed thawed for 3-4 months of the winter season, and deeper sediments remain within the range of 0 to -5 C whereas shallow sediment temperatures ranged between 10 and -10 C over an annual cycle. Laboratory experiments showed that little difference in CH4 production was observed at sediment temperatures between -2 and 5 C, whereas production was very low at -10 C. No significant differences in CH4 production rates were observed for different sediment depths in the laboratory. Field data collected between August 2010 and June 2011 showed consistent accumulation of CH4 in sediments following the formation of an ice layer on pond surfaces. However, CH4 concentrations in gas samplers decreased in February through April after sediments were frozen, but began to increase again (May-June) as sediments thawed and began to warm. Future work will include the examination

  17. Comparative methane emission by ratites: Differences in food intake and digesta retention level out methane production.

    PubMed

    Frei, Samuel; Hatt, Jean-Michel; Ortmann, Sylvia; Kreuzer, Michael; Clauss, Marcus

    2015-10-01

    Ratites differ in the anatomy of their digestive organs and their digesta excretion patterns. Ostriches (Struthio camelus) have large fermentation chambers and long digesta retention, emus (Dromaius novaehollandiae) have a short gut and short retention times, and rheas (Rhea americana) are intermediate. A recent study showed that ostriches produce as much methane (CH4) as expected for a similar-sized, non-ruminant mammalian herbivore. We hypothesized that emus and rheas produce less CH4 than ostriches. We individually measured, by chamber respirometry, the amount of O2 consumed as well as CO2 and CH4 emitted from six adult rheas (body mass 23.4±8.3 kg) and two adult emus (33.5 and 32.0 kg) during 23-hour periods on a pelleted lucerne diet. In contrast to previous studies, which classified emus as non-producers, we measured CH4 emissions at 7.39 and 6.25 L/day for emus and 2.87±0.82 L/day for rheas, which is close to values expected for similar-sized non-ruminant mammals for both species. O2 consumption was of a similar magnitude as reported previously. Across ratites, CH4 yield (L/kg dry matter intake) was positively correlated with mean retention time of food particles in the gut, similar to findings within ruminant species. In ratites, this relationship leads to similar body mass-specific CH4 production for a high intake/short retention and a low intake/long retention strategy. Therefore, when investigating CH4 production in herbivorous birds, it is advisable to consider various CH4 measures, not only yield or absolute daily amount alone.

  18. Influence of process parameters on the extraction of soluble substances from OFMSW and methane production.

    PubMed

    Campuzano, Rosalinda; González-Martínez, Simón

    2017-02-19

    Microorganisms involved in anaerobic digestion require dissolved substrates to transport them through the cell wall to different processing units and finally to be disposed as waste, such as methane and carbon dioxide. In order to increase methane production, this work proposes to separate the soluble substances from OFMSW and analyse methane production from extracts and OFMSW. Using water as solvent, four extraction parameters were proposed: (1) Number of consecutive extractions, (2) Duration of mixing for every consecutive extraction, (3) OFMSW to water mass ratios 1:1, 1:2, and 1:3 and, (4) The influence of temperature on the extraction process. Results indicated that is possible to separate 40% of VS from OFMSW with only three consecutive extraction with mixing of 30min in every extraction using ambient temperature water. For every OFMSW to water combination, the first three consecutive extracts were analysed for biochemical methane potential test during 21days at 35°C; OFMSW was also tested as reference. Methane production from all substrates is highest during the first day and then it slowly decreases to increase again during a second stage. This was identified as diauxic behaviour. Specific methane production at day 21 increased with increasing water content of the extracts where OFMSW methane production was the lowest of all with 535NL/kgVS. These results indicate that it is feasible to rapidly produce methane from extracted substances.

  19. Comparison of methane production potential, biodegradability, and kinetics of different organic substrates.

    PubMed

    Li, Yeqing; Zhang, Ruihong; Liu, Guangqing; Chen, Chang; He, Yanfeng; Liu, Xiaoying

    2013-12-01

    The methane production potential, biodegradability, and kinetics of a wide range of organic substrates were determined using a unified and simple method. Results showed that feedstocks that contained high energy density and easily degradable substrates exhibited high methane production potential and biodegradability. Lignocellulosic biomass with high content of fibrous compositions had low methane yield and biodegradability. Feedstocks with high lignin content (≥ 15%, on a TS basis) had low first-order rate constant (0.05-0.06 1/d) compared to others. A negative linear correlation between lignin content and experimental methane yield (or biodegradability) was found for lignocellulosic and manure wastes. This could be used as a fast method to predict the methane production potential and biodegradability of fiber-rich substrates. The findings of this study provided a database for the conversion efficiency of different organic substrates and might be useful for applications of biomethane potential assay and anaerobic digestion in the future.

  20. Soil redox and pH effects on methane production in a flooded rice soil

    SciTech Connect

    Wang, Z.P.; DeLaune, R.D.; Masscheleyn, P.H.; Patrick, W.H.

    1993-01-01

    Methane formation in soil is a microbiological process controlled by many factors. Of them soil redox potential (Eh) and soil pH are considered as critical controls. A laboratory incubation experiment was conducted to study the critical initiation soil Eh, the optimum soil pH, and the interaction of Eh and pH on methane production. A small decrease in pH resulting from the introduction of acidic materials significantly decreased methane production. However, a slight increase in soil pH (about 0.2 unit higher than the natural soil suspension pH) resulted in an enhancement of methane production by 11-20 percent and 24-25 percent at controlled Eh of -250 mV and -200 mV, respectively. Results suggest that decrease in methane emission could be obtained by a small reduction in soil pH in Crowley soil.

  1. Relationships linking primary production, sea ice melting, and biogenic aerosol in the Arctic

    NASA Astrophysics Data System (ADS)

    Becagli, S.; Lazzara, L.; Marchese, C.; Dayan, U.; Ascanius, S. E.; Cacciani, M.; Caiazzo, L.; Di Biagio, C.; Di Iorio, T.; di Sarra, A.; Eriksen, P.; Fani, F.; Giardi, F.; Meloni, D.; Muscari, G.; Pace, G.; Severi, M.; Traversi, R.; Udisti, R.

    2016-07-01

    This study examines the relationships linking methanesulfonic acid (MSA, arising from the atmospheric oxidation of the biogenic dimethylsulfide, DMS) in atmospheric aerosol, satellite-derived chlorophyll a (Chl-a), and oceanic primary production (PP), also as a function of sea ice melting (SIM) and extension of the ice free area in the marginal ice zone (IF-MIZ) in the Arctic. MSA was determined in PM10 samples collected over the period 2010-2012 at two Arctic sites, Ny Ålesund (78.9°N, 11.9°E), Svalbard islands, and Thule Air Base (76.5°N, 68.8°W), Greenland. PP is calculated by means of a bio-optical, physiologically based, semi-analytical model in the potential source areas located in the surrounding oceanic regions (Barents and Greenland Seas for Ny Ålesund, and Baffin Bay for Thule). Chl-a peaks in May in the Barents sea and in the Baffin Bay, and has maxima in June in the Greenland sea; PP follows the same seasonal pattern of Chl-a, although the differences in absolute values of PP in the three seas during the blooms are less marked than for Chl-a. MSA shows a better correlation with PP than with Chl-a, besides, the source intensity (expressed by PP) is able to explain more than 30% of the MSA variability at the two sites; the other factors explaining the MSA variability are taxonomic differences in the phytoplanktonic assemblages, and transport processes from the DMS source areas to the sampling sites. The taxonomic differences are also evident from the slopes of the correlation plots between MSA and PP: similar slopes (in the range 34.2-36.2 ng m-3of MSA/(gC m-2 d-1)) are found for the correlation between MSA at Ny Ålesund and PP in Barents Sea, and between MSA at Thule and PP in the Baffin Bay; conversely, the slope of the correlation between MSA at Ny Ålesund and PP in the Greenland Sea in summer is smaller (16.7 ng m-3of MSA/(gC m-2 d-1)). This is due to the fact that DMS emission from the Barents Sea and Baffin Bay is mainly related to the MIZ

  2. Effects of exogenous aerobic bacteria on methane production and biodegradation of municipal solid waste in bioreactors.

    PubMed

    Ge, Sai; Liu, Lei; Xue, Qiang; Yuan, Zhiming

    2016-09-01

    Landfill is the most common and efficient ways of municipal solid waste (MSW) disposal and the landfill biogas, mostly methane, is currently utilized to generate electricity and heat. The aim of this work is to study the effects and the role of exogenous aerobic bacteria mixture (EABM) on methane production and biodegradation of MSW in bioreactors. The results showed that the addition of EABM could effectively enhance hydrolysis and acidogenesis processes of MSW degradation, resulting in 63.95% reduction of volatile solid (VS), the highest methane production rate (89.83Lkg(-1) organic matter) ever recorded and a threefold increase in accumulative methane production (362.9L) than the control (127.1L). In addition, it is demonstrated that white-rot fungi (WRF) might further promote the methane production through highly decomposing lignin, but the lower pH value in leachate and longer acidogenesis duration may cause methane production reduced. The data demonstrated that methane production and biodegradation of MSW in bioreactors could be significantly enhanced by EABM via enhanced hydrolysis and acidogenesis processes, and the results are of great economic importance for the future design and management of landfill.

  3. Methane Production of Different Forages in In vitro Ruminal Fermentation

    PubMed Central

    Meale, S. J.; Chaves, A. V.; Baah, J.; McAllister, T. A.

    2012-01-01

    An in vitro rumen batch culture study was completed to compare effects of common grasses, leguminous shrubs and non-leguminous shrubs used for livestock grazing in Australia and Ghana on CH4 production and fermentation characteristics. Grass species included Andropodon gayanus, Brachiaria ruziziensis and Pennisetum purpureum. Leguminous shrub species included Cajanus cajan, Cratylia argentea, Gliricidia sepium, Leucaena leucocephala and Stylosanthes guianensis and non-leguminous shrub species included Annona senegalensis, Moringa oleifera, Securinega virosa and Vitellaria paradoxa. Leaves were harvested, dried at 55°C and ground through a 1 mm screen. Serum bottles containing 500 mg of forage, modified McDougall’s buffer and rumen fluid were incubated under anaerobic conditions at 39°C for 24 h. Samples of each forage type were removed after 0, 2, 6, 12 and 24 h of incubation for determination of cumulative gas production. Methane production, ammonia concentration and proportions of VFA were measured at 24 h. Concentration of aNDF (g/kg DM) ranged from 671 to 713 (grasses), 377 to 590 (leguminous shrubs) and 288 to 517 (non-leguminous shrubs). After 24 h of in vitro incubation, cumulative gas, CH4 production, ammonia concentration, proportion of propionate in VFA and IVDMD differed (p<0.05) within each forage type. B. ruziziensis and G. sepium produced the highest cumulative gas, IVDMD, total VFA, proportion of propionate in VFA and the lowest A:P ratios within their forage types. Consequently, these two species produced moderate CH4 emissions without compromising digestion. Grazing of these two species may be a strategy to reduce CH4 emissions however further assessment in in vivo trials and at different stages of maturity is recommended. PMID:25049482

  4. A modeling perspective on wetland methane production and emission

    NASA Astrophysics Data System (ADS)

    Xu, X.; Riley, W. J.; Koven, C. D.

    2014-12-01

    Methane (CH4) is the third most important greenhouse gas after H2O and CO2. The effects of global warming on wetland hydrology have a strong impact on wetland CH4 production and emission, via both hydrologic and biogeochemical processes, presenting a challenge to accurate projection of CH4 responses to climate change. We are working on the development of CH4 module—including CH4 production, consumption and transport processes— in the Community Land Model (CLM4.5) in order to estimate CH4 fluxes in a regional and global scale. However, high uncertainties are still present in sensitivity of CH4 production to soil temperature, hydrology, pH and redox potential, rough treatment to vertical soil resolution and fractional inundation, and simplified parameterizing of CH4 transport and emissions. Our research aims to (1) use tower eddy covariance and aircraft measurements of CH4 concentration and surface flux to test the CH4 processes in CLM model; (2) obtain a better understanding and parameterization of the biogeochemical and biogeophysical processes of high latitude wetland CH4 production and emission; (3) assess impact of climate variability on wetland CH4 emission. Our analysis of CLM shows that the modeled predictions of the seasonal cycle of CH4 in high latitude wetlands is very sensitive to active layer hydrological cycle. The abrupt soil water increase in the period of soil thawing and snow melting leads to unrealistically large emissions of CH4 during the spring season. We present improvements required to generate realistic seasonal cycles of high latitude CH4 fluxes in the model.

  5. Compilation of a biogenic hydrocarbon emissions inventory for evaluating ozone-control strategies in the San Francisco Bay Area

    SciTech Connect

    Hunsaker, D.B. Jr.; Moreland, R.M.

    1982-01-01

    The body of information presented is directed to planners and engineers concerned with developing ozone control strategies. A biogenic hydrocarbon emissions inventory for the San Francisco Bay Area has been prepared for use in determining the degree of hydrocarbon emissions control needed to attain the ozone standard. Remote sensing imagery was used to characterize the regional vegetation distribution, and a Delphi survey of scientists familiar with biogenic emissions was used to provide biogenic hydrocarbon emission factors. For a hypothetical 24-hour period of twelve hours of darkness and twelve hours of light, biogenic sources in the nine-county Bay Area were estimated to produce about 4.5 x 10/sup 5/ kg (500 tons) of total non-methane hydrocarbons; the uncertainty of this estimate was calculated to be +- 50%. The biogenic emissions were found to represent about 33% of the man-made and natural hydrocarbon emissions in the region. The magnitude of the biogenic emissions inventory is not the key factor from which the contribution of biogenic sources to urban ozone production can be discerned. Photochemical dispersion modeling of the total (man-made plus natural) hydrocarbon emissions inventory is recommended as a tool to help understand the contribution of biogenic sources to excessive amounts of the ozone standard in the San Francisco Bay Area.

  6. Biodegradability and methane production from secondary paper and pulp sludge: effect of fly ash and modeling.

    PubMed

    Huiliñir, César; Montalvo, Silvio; Guerrero, Lorna

    2015-01-01

    The effect of fly ash on biodegradability and methane production from secondary paper and pulp sludge, including its modeling, was evaluated. Three tests with fly ash concentrations of 0, 10 and 20 mg/L were evaluated at 32 °C. Methane production was modeled using the modified Gompertz equation. The results show that the doses used produce a statistically significant increase of accumulated methane, giving values greater than 225 mL of CH4 per gram of volatile solids (VS) added, and 135% greater than that obtained in the control assay. Biodegradability of VS increased 143% with respect to the control assays, giving values around 43%. The modified Gompertz model can describe well methane generation from residual sludge of the paper industry water treatment, with parameter values between those reported in the literature. Thus, the addition of fly ash to the process causes a significant increase of accumulated methane and VS removal, improving the biodegradability of paper and pulp sludge.

  7. NREL Advancements in Methane Conversion Lead to Cleaner Air, Useful Products

    SciTech Connect

    2016-06-01

    Researchers at NREL leveraged the recent on-site development of gas fermentation capabilities and novel genetic tools to directly convert methane to lactic acid using an engineered methanotrophic bacterium. The results provide proof-of-concept data for a gas-to-liquids bioprocess that concurrently produces fuels and chemicals from methane. NREL researchers developed genetic tools to express heterologous genes in methanotrophic organisms, which have historically been difficult to genetically engineer. Using these tools, researchers demonstrated microbial conversion of methane to lactate, a high-volume biochemical precursor predominantly utilized for the production of bioplastics. Methane biocatalysis offers a means to concurrently liquefy and upgrade natural gas and renewable biogas, enabling their utilization in conventional transportation and industrial manufacturing infrastructure. Producing chemicals and fuels from methane expands the suite of products currently generated from biorefineries, municipalities, and agricultural operations, with the potential to increase revenue and significantly reduce greenhouse gas emissions.

  8. Subsurface characterization of methane production and oxidation from a New Hampshire wetland.

    PubMed

    Shoemaker, J K; Schrag, D P

    2010-06-01

    We measured the carbon isotopic composition of pore water carbon dioxide from Sallie's Fen, a New Hampshire poor fen. The isotope profiles are used in combination with a one-dimensional diffusion-reaction model to calculate rates of methane production, oxidation and transport over an annual cycle. We show how the rates vary with depth over a seasonal cycle, with methane produced deeper during the winter months and at progressively shallower depths into the summer season. The rates of methane production, constrained by the measured delta(13)C(dic) profiles, cannot explain high methane emission during the summer. We suggest that much of the methane produced during this time comes either from the unsaturated peat, or from the top 1-3 cm of saturated peat where episodic exchange with the atmosphere makes it invisible to our method.

  9. A search for biogenic trace gases in the atmosphere of Mars

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.; Mckay, Christopher P.

    1989-01-01

    The detection of certain trace gases in the atmosphere of Mars may serve as a possible indicator of microbial life on the surface of Mars. Candidate biogenic gases include methane CH4, ammonia NH3, nitrous oxide N2O, and several reduced sulfur species. Chemical thermodynamic equilibrium and photochemical calculations preclude the presence of these gases in any measurable concentrations in the atmosphere of Mars in the absence of biogenic production. A search for these gases utilizing either high resolution (spectral and spatial) spectroscopy from a Mars orbiter, such as the Observer, and or in situ measurements from a Mars lander or rover, is proposed.

  10. Methane Production and Transport within the Marsh Biome of Biosphere 2

    NASA Technical Reports Server (NTRS)

    Molnar, Jennifer; Goodridge, Kelven

    1997-01-01

    In recent decades, the concentration of methane in the earth's atmosphere increased 1-2% annually. It's rate of increases, combined with methane's effectiveness as a greenhouse gas, has led to an intensive research effort to determine the sources and sinks of the gas in the environment. Biosphere 2 offers a unique opportunity to contribute to the effort because it lacks a major photochemical sink present in the Earth's atmosphere. Researchers can therefore concentrate on biological processes involved in methane cycles. Wetlands are a large source of atmospheric methane, due to anoxic conditions in the sediments and the abundance of organic materials. In order to determine if these conditions in Biosphere 2 also promote methane production, this study looked for the fluxes of methane and methods of transport of the gas from from the water and sediments to the atmosphere in the Marsh Biome. Fluxes of methane from the sediments and waters were measured using static chambers, peepers, and leaf bags. Fluxes and vertical profiles of methane in the sediments show that substantial amounts of methane are being produced in the marsh and are being transported into the Biosphere 2 environment.

  11. Thermodynamic, transport, and flow properties of gaseous products resulting from combustion of methane-air-oxygen

    NASA Technical Reports Server (NTRS)

    Klich, G. F.

    1976-01-01

    Results of calculations to determine thermodynamic, transport, and flow properties of combustion product gases are presented. The product gases are those resulting from combustion of methane-air-oxygen and methane-oxygen mixtures. The oxygen content of products resulting from the combustion of methane-air-oxygen mixtures was similiar to that of air; however, the oxygen contained in products of methane-oxygen combustion ranged from 20 percent by volume to zero for stoichiometric combustion. Calculations were made for products of reactant mixtures with fuel percentages, by mass, of 7.5 to 20. Results are presented for specific mixtures for a range of pressures varying from 0.0001 to 1,000 atm and for temperatures ranging from 200 to 3,800 K.

  12. Effect of the interaction between a low tyramine-producing Lactobacillus and proteolytic staphylococci on biogenic amine production during ripening and storage of dry sausages.

    PubMed

    Bover-Cid, S; Izquierdo-Pulido, M; Vidal-Carou, M C

    2001-04-11

    The interaction between tyrosine-decarboxylase and proteolytic activities of a Lactobacillus curvatus and Staphylococcus xylosus, respectively, on biogenic amine production during the ripening and the storage of dry fermented sausages was investigated. Water content, pH, proteolysis parameters, microbial counts, and biogenic amine contents were monitored in spontaneously and starter fermented sausages. The use of proteolytic staphylococci as starter resulted in a higher content of non-protein nitrogen and total free amino acids. Tyramine was the main amine produced in all batches. However, tyrosine-decarboxylase activity of the L. curvatus starter strain was weak and yielded lower amounts of tyramine than those produced by the wild mioroflora in the control batch. Association between tyramine production and proteolysis could only be established in a defectively dried batch. Putrescine and cadaverine accumulation was efficiently reduced in the starter-mediated fermentation, in agreement with the lower development of enterobacteria. Phenylethylamine and tryptamine were only detected in the spontaneously fermented sausages, while histamine, spermine and spermidine did not vary during the ripening. Biogenic amine levels and related parameters showed significant changes during the storage of dry sausages depending on the temperature and the batch. As a general rule, changes in the pH, proteolysis, microbial counts, and biogenic amine contents were stronger at 19 degrees C than at 4 degrees C. The results suggest that refrigeration would be advisable for preventing further accumulation of biogenic amines during the storage of dry fermented sausages.

  13. Evaluation of Phytoremediation of Coal Bed Methane Product Water and Waters of Quality Similar to that Associated with Coal Bed Methane Reserves of the Powder River Basin, Montana and Wyoming

    SciTech Connect

    James Bauder

    2008-09-30

    U.S. emphasis on domestic energy independence, along with advances in knowledge of vast biogenically sourced coalbed methane reserves at relatively shallow sub-surface depths with the Powder River Basin, has resulted in rapid expansion of the coalbed methane industry in Wyoming and Montana. Techniques have recently been developed which constitute relatively efficient drilling and methane gas recovery and extraction techniques. However, this relatively efficient recovery requires aggressive reduction of hydrostatic pressure within water-saturated coal formations where the methane is trapped. Water removed from the coal formation during pumping is typically moderately saline and sodium-bicarbonate rich, and managed as an industrial waste product. Current approaches to coalbed methane product water management include: surface spreading on rangeland landscapes, managed irrigation of agricultural crop lands, direct discharge to ephermeral channels, permitted discharge of treated and untreated water to perennial streams, evaporation, subsurface injection at either shallow or deep depths. A Department of Energy-National Energy Technology Laboratory funded research award involved the investigation and assessment of: (1) phytoremediation as a water management technique for waste water produced in association with coalbed methane gas extraction; (2) feasibility of commercial-scale, low-impact industrial water treatment technologies for the reduction of salinity and sodicity in coalbed methane gas extraction by-product water; and (3) interactions of coalbed methane extraction by-product water with landscapes, vegetation, and water resources of the Powder River Basin. Prospective, greenhouse studies of salt tolerance and water use potential of indigenous, riparian vegetation species in saline-sodic environments confirmed the hypothesis that species such as Prairie cordgrass, Baltic rush, American bulrush, and Nuttall's alkaligrass will thrive in saline-sodic environments when

  14. Biogeochemistry of microbial coal-bed methane

    USGS Publications Warehouse

    Strc, D.; Mastalerz, Maria; Dawson, K.; MacAlady, J.; Callaghan, A.V.; Wawrik, B.; Turich, C.; Ashby, M.

    2011-01-01

    Microbial methane accumulations have been discovered in multiple coal-bearing basins over the past two decades. Such discoveries were originally based on unique biogenic signatures in the stable isotopic composition of methane and carbon dioxide. Basins with microbial methane contain either low-maturity coals with predominantly microbial methane gas or uplifted coals containing older, thermogenic gas mixed with more recently produced microbial methane. Recent advances in genomics have allowed further evaluation of the source of microbial methane, through the use of high-throughput phylogenetic sequencing and fluorescent in situ hybridization, to describe the diversity and abundance of bacteria and methanogenic archaea in these subsurface formations. However, the anaerobic metabolism of the bacteria breaking coal down to methanogenic substrates, the likely rate-limiting step in biogenic gas production, is not fully understood. Coal molecules are more recalcitrant to biodegradation with increasing thermal maturity, and progress has been made in identifying some of the enzymes involved in the anaerobic degradation of these recalcitrant organic molecules using metagenomic studies and culture enrichments. In recent years, researchers have attempted lab and subsurface stimulation of the naturally slow process of methanogenic degradation of coal. Copyright ?? 2011 by Annual Reviews. All rights reserved.

  15. Methane production and recovery using potato waste solubles and solids

    SciTech Connect

    Jackson, M.L.

    1982-01-01

    The production and recovery of methane gas utilizing various potato conversion wastes in either soluble or solid form is discussed in this chapter. Such wastes may occur at temperatures ranging from 25 C to as high as 55 C. The form and concentration of the waste and the temperature may dictate the choice of one of several possible treatment processes which are variously designated as conventional (holding tanks), contact (recycle of cell solids), and filter (packed bed) reactors. To this may be added a recent concept of an expanded bed reactor. A first design approach was employed to approximate capital and operating costs with an evaluation of the internal rates of return on investment and payout times. The fraction of the energy required by a processing plant which could be provided by the gas produced was of interest as a potential supplemental source of energy in the event that natural gas supplies are reduced or that prices of this fuel continue to escalate rapidly.

  16. Methane production from coal by a single methanogen

    NASA Astrophysics Data System (ADS)

    Mayumi, Daisuke; Mochimaru, Hanako; Tamaki, Hideyuki; Yamamoto, Kyosuke; Yoshioka, Hideyoshi; Suzuki, Yuichiro; Kamagata, Yoichi; Sakata, Susumu

    2016-10-01

    Coal-bed methane is one of the largest unconventional natural gas resources. Although microbial activity may greatly contribute to coal-bed methane formation, it is unclear whether the complex aromatic organic compounds present in coal can be used for methanogenesis. We show that deep subsurface-derived Methermicoccus methanogens can produce methane from more than 30 types of methoxylated aromatic compounds (MACs) as well as from coals containing MACs. In contrast to known methanogenesis pathways involving one- and two-carbon compounds, this “methoxydotrophic” mode of methanogenesis couples O-demethylation, CO2 reduction, and possibly acetyl-coenzyme A metabolism. Because MACs derived from lignin may occur widely in subsurface sediments, methoxydotrophic methanogenesis would play an important role in the formation of natural gas not limited to coal-bed methane and in the global carbon cycle.

  17. Methane Production by Methanogens in Perchlorate-supplemented Media

    NASA Astrophysics Data System (ADS)

    Howe, K. L.; Gavin, P.; Goodhart, T.; Kral, T. A.

    2009-03-01

    Perchlorates, found on the martian surface, create a harsh environment. Methanogens are familiar with harsh environments and their growth was tested in perchlorate salt media. All four species of methanogens produced methane at all concentrations of each salt tested.

  18. Methane production from coal by a single methanogen.

    PubMed

    Mayumi, Daisuke; Mochimaru, Hanako; Tamaki, Hideyuki; Yamamoto, Kyosuke; Yoshioka, Hideyoshi; Suzuki, Yuichiro; Kamagata, Yoichi; Sakata, Susumu

    2016-10-14

    Coal-bed methane is one of the largest unconventional natural gas resources. Although microbial activity may greatly contribute to coal-bed methane formation, it is unclear whether the complex aromatic organic compounds present in coal can be used for methanogenesis. We show that deep subsurface-derived Methermicoccus methanogens can produce methane from more than 30 types of methoxylated aromatic compounds (MACs) as well as from coals containing MACs. In contrast to known methanogenesis pathways involving one- and two-carbon compounds, this "methoxydotrophic" mode of methanogenesis couples O-demethylation, CO2 reduction, and possibly acetyl-coenzyme A metabolism. Because MACs derived from lignin may occur widely in subsurface sediments, methoxydotrophic methanogenesis would play an important role in the formation of natural gas not limited to coal-bed methane and in the global carbon cycle.

  19. Does Dietary Mitigation of Enteric Methane Production Affect Rumen Function and Animal Productivity in Dairy Cows?

    PubMed Central

    Veneman, Jolien B.; Muetzel, Stefan; Hart, Kenton J.; Faulkner, Catherine L.; Moorby, Jon M.; Perdok, Hink B.; Newbold, Charles J.

    2015-01-01

    It has been suggested that the rumen microbiome and rumen function might be disrupted if methane production in the rumen is decreased. Furthermore concerns have been voiced that geography and management might influence the underlying microbial population and hence the response of the rumen to mitigation strategies. Here we report the effect of the dietary additives: linseed oil and nitrate on methane emissions, rumen fermentation, and the rumen microbiome in two experiments from New Zealand (Dairy 1) and the UK (Dairy 2). Dairy 1 was a randomized block design with 18 multiparous lactating cows. Dairy 2 was a complete replicated 3 x 3 Latin Square using 6 rumen cannulated, lactating dairy cows. Treatments consisted of a control total mixed ration (TMR), supplementation with linseed oil (4% of feed DM) and supplementation with nitrate (2% of feed DM) in both experiments. Methane emissions were measured in open circuit respiration chambers and rumen samples were analyzed for rumen fermentation parameters and microbial population structure using qPCR and next generation sequencing (NGS). Supplementation with nitrate, but not linseed oil, decreased methane yield (g/kg DMI; P<0.02) and increased hydrogen (P<0.03) emissions in both experiments. Furthermore, the effect of nitrate on gaseous emissions was accompanied by an increased rumen acetate to propionate ratio and consistent changes in the rumen microbial populations including a decreased abundance of the main genus Prevotella and a decrease in archaeal mcrA (log10 copies/ g rumen DM content). These results demonstrate that methane emissions can be significantly decreased with nitrate supplementation with only minor, but consistent, effects on the rumen microbial population and its function, with no evidence that the response to dietary additives differed due to geography and different underlying microbial populations. PMID:26509835

  20. The effects of acid deposition on sulfate reduction and methane production in peatlands

    NASA Technical Reports Server (NTRS)

    Murray, Georgia L.; Hines, Mark E.; Bayley, Suzanne E.

    1992-01-01

    Peatlands, as fens and bods, make up a large percentage of northern latitude terrestrial environments. They are organic rich and support an active community of anaerobic bacteria, such as methanogenic and sulfate-reducing bacteria. The end products of these microbial activities, methane and hydrogen sulfide, are important components in the global biogeochemical cycles of carbon and sulfur. Since these two bacterial groups compete for nutritional substrates, increases in sulfate deposition due to acid rain potentially can disrupt the balance between these processes leading to a decrease in methane production and emission. This is significant because methane is a potent greenhouse gas that effects the global heat balance. A section of Mire 239 in the Experimental Lakes Area, in Northwestern Ontario, was artificially acidified and rates of sulfate reduction and methane production were measured with depth. Preliminary results suggested that methane production was not affected immediately after acidification. However, concentrations of dissolved methane decreased and dissolved sulfide increased greatly after acidification and both took several days to recover. The exact mechanism for the decrease in methane was not determined. Analyses are under way which will be used to determine rates of sulfate reduction. These results will be available by Spring and will be discussed.

  1. Coupling of Sinking Biogenic Particulate Fluxes and Primary Production in the Euphotic Zone of the Cariaco Basin, Venezuela

    NASA Astrophysics Data System (ADS)

    Montes-Herrera, E.; Muller-Karger, F. E.; Thunell, R.; Hollander, D.; Astor, Y.; Varela, R.; Soto, I.; Lorenzoni, L.

    2007-12-01

    Only 1% of the organic matter produced in the upper ocean by photosynthesis reaches depths below 1500 m due to dissolution and microbial degradation. Recent work shows that the vertical flux of particulate organic carbon (POC) is strongly correlated with the settling flux of minerals like calcium carbonate, opal and lithogenic material. These act as ballast and also provide physical protection against degradation of POC. Results from the CARIACO (Carbon Retention in a Colored Ocean) time series program support this hypothesis. For over ten years, CARIACO has been studying the connections between primary production (PP) and the biogeochemical features of sinking particles in the Cariaco Basin, Venezuela, with moored sediment traps that collect settling matter at five depths between 125 and 1300 m on a bi-weekly basis. The geomorphology of the basin restricts deep water ventilation, leading to anoxia below 250 m. Although the Cariaco Basin exhibits strong seasonal production cycles related to wind-driven upwelling, the flux of biogenic matter at all depths below the oxic-anoxic interface is not significantly correlated to primary production. In order to understand the flux of particles in the upper 100 m of the water column, deployments of drifting sediment traps in the Cariaco Basin were carried out from March to July 2007, collecting settling material at 50 and 100 m. The hypothesis is that the flux of sinking material through the euphotic zone may be less affected by decomposition and dissolution than material reaching the deep moored traps. Initial results show significant differences in POC, PON and carbonate flux rates between 50 and 100 m. They also exhibit significant differences in the flux rates of these components between upwelling vs. relaxation periods, suggesting potential connections among seasonal changes in surface chlorophyll a concentrations, plankton community structure, and the vertical export of biogenic materials. We describe results from this

  2. Characteristics of the organic fraction of municipal solid waste and methane production: A review.

    PubMed

    Campuzano, Rosalinda; González-Martínez, Simón

    2016-08-01

    Anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) is a viable alternative for waste stabilization and energy recovery. Biogas production mainly depends on the type and amount of organic macromolecules. Based on results from different authors analysing OFMSW from different cities, this paper presents the importance of knowing the OFMSW composition to understand how anaerobic digestion can be used to produce methane. This analysis describes and discusses physical, chemical and bromatological characteristics of OFMSW reported by several authors from different countries and cities and their relationship to methane production. The main conclusion is that the differences are country and not city dependant. Cultural habits and OFMSW management systems do not allow a generalisation but the individual analysis for specific cities allow understanding the general characteristics for a better methane production. Not only are the OFMSW characteristics important but also the conditions under which the methane production tests were performed.

  3. Economic tools for realization of methane production project on Kuzbass coal deposits

    NASA Astrophysics Data System (ADS)

    Sharf, I.; Sokolova, M.; Kochetkova, O.; Dmitrieva, N.

    2016-09-01

    Environmental issues and, above all, issues related to the release of greenhouse gases into the atmosphere, such as coal bed methane, actualize the challenge of searching a variety of options for its disposal. The difference in the macroeconomic, industrial, geological and infrastructural features determine the need to choose the most cost-effective option for using of methane emitted from the coal deposits. Various economic ways to improve the profitability of production are viewed on the basis of the analysis of methane production project from Kuzbass coal deposits, Kemerovo region, Russia.

  4. The role of purine degradation in methane biosynthesis and energy production in Methanococcus vannielii

    SciTech Connect

    DeMoll, E.

    1990-10-22

    Research continues on the role of purine degradation in methane biosynthesis and energy production in Methanococcus vannielii. This report summarizes current progress of the research. Topics include: A survey of other methanogens for the purine degradation pathway; isolate and characterize the enzyme and products of formiminoglycine cleavage; ascertain the fate of glycine from the formiminoglycine cleavage; elucidate the route of incorporation of the formyl moiety of formiminoglycine into methane biosynthesis; determine the percent methane and amino acid synthesis from purine degradation; and related studies on xanthine dehydrogenase and pyrimidine degradation of M. Vannielii. (SM)

  5. Glycoproteins as substrates for production of hydrogen and methane by colonic bacterial flora.

    PubMed

    Perman, J A; Modler, S

    1982-08-01

    Hydrogen and methane in human breath derive entirely from bacterial fermentation in the intestinal lumen. The sources of substrates utilized for these reactions have not been completely determined. Basal excretion of both gases occurs in the fasted state, while malabsorbed carbohydrate commonly results in increased hydrogen but not methane production. Using an in vitro fecal incubation system, we have studied hydrogen and methane production from glycoproteins of endogenous as well as dietary origin. All glycoproteins tested yielded hydrogen when incubated with fecal homogenates. Mean hydrogen production from substrates containing less than 3% sugar (human serum albumin, bovine serum albumin, and alpha-casein) averaged 2.2 +/- 0.9% of hydrogen production from equivalent amounts of glucose, while carbohydrate-rich mucin yielded 46.0 +/- 6.7% of hydrogen production from glucose. Glycoproteins of intermediate carbohydrate content, including transferrin and egg white, yielded intermediate values. Methane production from glycoproteins was optimal from carbohydrate-poor protein substrates in fecal homogenates which accumulated hydrogen and became rapidly acidic when incubated with pure carbohydrate. In contrast, methane production was comparable for essentially sugar-free proteins, glycoproteins, and glucose when hydrogen did not accumulate and neutral pH was maintained. We conclude that glycoproteins are substrates for hydrogen and methane production by colonic bacteria from healthy adults. In individuals with bacterial overgrowth syndromes and in protein-losing enteropathy, bacterial catabolism of endogenous glycoproteins may cause increased basal hydrogen and methane excretion. These findings also raise the possibility that measurement of hydrogen or methane after oral administration of dietary glycoproteins may be useful in detection of protein malabsorption.

  6. Microbial diversity and dynamics during methane production from municipal solid waste

    SciTech Connect

    Bareither, Christopher A.; Wolfe, Georgia L.; McMahon, Katherine D.; Benson, Craig H.

    2013-10-15

    Highlights: ► Similar bacterial communities developed following different start-up operation. ► Total methanogens in leachate during the decelerated methane phase reflected overall methane yield. ► Created correlations between methanogens, methane yield, and available substrate. ► Predominant bacteria identified with syntrophic polysaccharide degraders. ► Hydrogenotrophic methanogens were dominant in the methane generation process. - Abstract: The objectives of this study were to characterize development of bacterial and archaeal populations during biodegradation of municipal solid waste (MSW) and to link specific methanogens to methane generation. Experiments were conducted in three 0.61-m-diameter by 0.90-m-tall laboratory reactors to simulate MSW bioreactor landfills. Pyrosequencing of 16S rRNA genes was used to characterize microbial communities in both leachate and solid waste. Microbial assemblages in effluent leachate were similar between reactors during peak methane generation. Specific groups within the Bacteroidetes and Thermatogae phyla were present in all samples and were particularly abundant during peak methane generation. Microbial communities were not similar in leachate and solid fractions assayed at the end of reactor operation; solid waste contained a more abundant bacterial community of cellulose-degrading organisms (e.g., Firmicutes). Specific methanogen populations were assessed using quantitative polymerase chain reaction. Methanomicrobiales, Methanosarcinaceae, and Methanobacteriales were the predominant methanogens in all reactors, with Methanomicrobiales consistently the most abundant. Methanogen growth phases coincided with accelerated methane production, and cumulative methane yield increased with increasing total methanogen abundance. The difference in methanogen populations and corresponding methane yield is attributed to different initial cellulose and hemicellulose contents of the MSW. Higher initial cellulose and

  7. Methane Detection for Oil and Gas Production Sites Using Portable Dual-Comb Spectrometry

    NASA Astrophysics Data System (ADS)

    Coburn, Sean; Wright, Robert; Cossel, Kevin C.; Truong, Gar-Wing; Baumann, Esther; Coddington, Ian; Newbury, Nathan R.; Alden, Caroline; Ghosh, Subhomoy; Prasad, Kuldeep; Rieker, Greg B.

    2016-06-01

    Considerable uncertainty exists regarding the contribution of oil and gas operations to anthropogenic emissions of atmospheric methane. Additionally, new proposed EPA regulations on volatile organic compound (VOC) emissions from oil and gas production facilities have been expanded to include methane, making this a topic of growing importance to the oil and gas industry as well as regulators. In order to gain a better understanding of emissions, reliable techniques that enable long-term monitoring of entire production facilities are needed. Recent advances in the development of compact and robust fiber frequency combs are enabling the use of this powerful spectroscopic tool outside of the laboratory. Here we characterize and demonstrate a dual comb spectrometer (DCS) system with the potential to locate and size methane leaks from oil and gas production sites over extended periods of time. The DCS operates over kilometer scale open paths, and the path integrated methane measurements will ultimately be coupled with an atmospheric inversion utilizing local meteorology and a high resolution fluid dynamics simulation to determine leak location and also derive a leak rate. High instrument precision is needed in order to accurately perform the measurement inversion on the highly varying methane background, thus the DCS system has been fully optimized for the detection of atmospheric methane in the methane absorption region around 180-184 THz.

  8. Comparison of Nonprecious Metal Cathode Materials for Methane Production by Electromethanogenesis

    PubMed Central

    2014-01-01

    In methanogenic microbial electrolysis cells (MMCs), CO2 is reduced to methane using a methanogenic biofilm on the cathode by either direct electron transfer or evolved hydrogen. To optimize methane generation, we examined several cathode materials: plain graphite blocks, graphite blocks coated with carbon black or carbon black containing metals (platinum, stainless steel or nickel) or insoluble minerals (ferrihydrite, magnetite, iron sulfide, or molybdenum disulfide), and carbon fiber brushes. Assuming a stoichiometric ratio of hydrogen (abiotic):methane (biotic) of 4:1, methane production with platinum could be explained solely by hydrogen production. For most other materials, however, abiotic hydrogen production rates were insufficient to explain methane production. At −600 mV, platinum on carbon black had the highest abiotic hydrogen gas formation rate (1600 ± 200 nmol cm–3 d–1) and the highest biotic methane production rate (250 ± 90 nmol cm–3 d–1). At −550 mV, plain graphite (76 nmol cm–3 d–1) performed similarly to platinum (73 nmol cm–3 d–1). Coulombic recoveries, based on the measured current and evolved gas, were initially greater than 100% for all materials except platinum, suggesting that cathodic corrosion also contributed to electromethanogenic gas production. PMID:24741468

  9. Sulfide and methane production in sewer sediments: Field survey and model evaluation.

    PubMed

    Liu, Yiwen; Tugtas, A Evren; Sharma, Keshab R; Ni, Bing-Jie; Yuan, Zhiguo

    2016-02-01

    Sewer sediment processes have been reported to significantly contribute to overall sulfide and methane production in sewers, at a scale comparable to that of sewer biofilms. The physiochemical and biological characteristics of sewer sediments are heterogeneous; however, the variability of in-sediments sulfide and methane production rates among sewers has not been assessed to date. In this study, five sewer sediment samples were collected from two cities in Australia with different climatic conditions. Batch assays were conducted to determine the rates of sulfate reduction and methane production under different flow velocity (shear stress) conditions as well as under completely mixed conditions. The tests showed substantial and variable sulfate reduction and methane production activities among different sediments. Sulfate reduction and methane production from sewer sediments were confirmed to be areal processes, and were dependent on flow velocity/shear stress. Despite of the varying characteristics and reactions kinetics, the sulfate reduction and methane production processes in all sediments could be well described by a one-dimensional sewer sediment model recently developed based on results obtained from a laboratory sewer sediment reactor. Model simulations indicated that the in-situ contribution of sewer sediment emissions could be estimated without the requirement of measuring the specific sediment characteristics or the sediment depths.

  10. Methyl-coenzyme M reductase A as an indicator to estimate methane production from dairy cows.

    PubMed

    Aguinaga Casañas, M A; Rangkasenee, N; Krattenmacher, N; Thaller, G; Metges, C C; Kuhla, B

    2015-06-01

    The evaluation of greenhouse gas mitigation strategies requires the quantitative assessment of individual methane production. Because methane measurement in respiration chambers is highly accurate, but also comprises various disadvantages such as limited capacity and high costs, the establishment of an indicator for estimating methane production of individual ruminants would provide an alternative to direct methane measurement. Methyl-coenzyme M reductase is involved in methanogenesis and the subunit α of methyl-coenzyme M reductase is encoded by the mcrA gene of rumen archaea. We therefore examined the relationship between methane emissions of Holstein dairy cows measured in respiration chambers with 2 different diets (high- and medium-concentrate diet) and the mcrA DNA and mcrA cDNA abundance determined from corresponding rumen fluid samples. Whole-body methane production per kilogram of dry matter intake and mcrA DNA normalized to the abundance of the rrs gene coding for 16S rRNA correlated significantly when using qmcrA primers. Use of qmcrA primers also revealed linear correlation between mcrA DNA copy number and methane yield. Regression analyses based on normalized mcrA cDNA abundances revealed no significant linear correlation with methane production per kilogram of dry matter intake. Furthermore, the correlations between normalized mcrA DNA abundance and the rumen fluid concentration of acetic and isobutyric acid were positive, whereas the correlations with propionic and lactic acid were negative. These data suggest that the mcrA DNA approach based on qmcrA primers could potentially be a molecular proxy for methane yield after further refinement.

  11. Real-time in situ δ13C Methane Measurements with a Cavity Ring-Down Spectrometer at Four Corners to Discriminate Biogenic and Thermogenic Sources

    NASA Astrophysics Data System (ADS)

    Arata, C.; Dubey, M. K.

    2012-12-01

    We characterized the performance of a new cavity ring-down δ13C isotopic CH4 spectrometer (Picarro G2123-i) in the laboratory. Our Allan variance plots show that the instrument can integrate 1-second measurements over 5 minutes to yield a precision better than ± 1 per mil. We subsequently deployed it at a field site at Four Corners (FC), New Mexico, where we had observed large sustained CH4 enhancements (2-8 ppm peaks for hours) at night. Potential sources of this large CH4 signal at FC include (1) fugitive emissions from coal mining and gas processing that are thermogenic and isotopically heavy and (2) Emissions from agriculture, ruminants, fires, and landfills that are biogenic and isotopically light. We analyze our measurements of δ13C of CH4 during spring and summer of 2012 to distinguish these two types of sources. We find CH4 plumes that are both isotopically heavy and light at our site. Keeling plots show two distinct limiting δ13C source compositions of -40 per mil and -60 per mil that we attribute to thermogenic and biogenic sources respectively. We use our results to quantify the contributions of these two sources and combine them with meteorological data to identify their sources in the Four Corners regions.

  12. Semi-continuous methane production from undiluted brown algae using a halophilic marine microbial community.

    PubMed

    Miura, Toyokazu; Kita, Akihisa; Okamura, Yoshiko; Aki, Tsunehiro; Matsumura, Yukihiko; Tajima, Takahisa; Kato, Junichi; Nakashimada, Yutaka

    2016-01-01

    Acclimated marine sediment-derived culture was used for semi-continuous methane production from materials equivalent to raw brown algae, without dilution of salinity and without nutrient supply, under 3 consecutive conditions of varying organic loading rates (OLRs) and hydraulic retention time (HRT). Methane production was stable at 2.0gVS/kg/day (39-day HRT); however, it became unstable at 2.9gVS/kg/day (28-day HRT) due to acetate and propionate accumulation. OLR subsequently decreased to 1.7gVS/kg/day (46-day HRT), stabilizing methane production beyond steady state. Methane yield was above 300mL/g VS at all OLRs. These results indicated that the acclimated marine sediment culture was able to produce methane semi-continuously from raw brown algae without dilution and nutrient supply under steady state. Microbial community analysis suggested that hydrogenotrophic methanogens predominated among archaea during unstable methane production, implying a partial shift of the methanogenic pathway from acetoclastic methanogenesis to acetate oxidation.

  13. Evaluation of marine sediments as microbial sources for methane production from brown algae under high salinity.

    PubMed

    Miura, Toyokazu; Kita, Akihisa; Okamura, Yoshiko; Aki, Tsunehiro; Matsumura, Yukihiko; Tajima, Takahisa; Kato, Junichi; Nakashimada, Yutaka

    2014-10-01

    Various marine sediments were evaluated as promising microbial sources for methane fermentation of Saccharina japonica, a brown alga, at seawater salinity. All marine sediments tested produced mainly acetate among volatile fatty acids. One marine sediment completely converted the produced volatile fatty acids to methane in a short period. Archaeal community analysis revealed that acetoclastic methanogens belonging to the Methanosarcina genus dominated after cultivation. Measurement of the specific conversion rate at each step of methane production under saline conditions demonstrated that the marine sediments had higher conversion rates of butyrate and acetate than mesophilic methanogenic granules. These results clearly show that marine sediments can be used as microbial sources for methane production from algae under high-salt conditions without dilution.

  14. Comparison between ensilage and fungal pretreatment for storage of giant reed and subsequent methane production.

    PubMed

    Liu, Shan; Xu, Fuqing; Ge, Xumeng; Li, Yebo

    2016-06-01

    Ensilage and fungal pretreatment of giant reed harvested from August through December were compared based on their effects on feedstock preservation, glucose yield, and subsequent methane production via anaerobic digestion (AD). Compared to fungal pretreatment, ensilage obtained lower total solids (<1.2%) and cellulose (<3.5%) losses, and comparable hemicellulose degradation, except for giant reed harvested in August. Ensilage increased glucose and methane yields by 7-15% and 4-14%, respectively, for giant reed harvested from August through December. Fungal pretreatment failed for giant reed harvested in August and October with reduced glucose yields, and was effective for that harvested in November and December, with about 20% increases in glucose yield. However, hydrocarbon losses during fungal pretreatment offset the increased glucose yield, resulting in decreased methane yields by AD. In summary, ensilage was found to be more suitable than fungal pretreatment for giant reed storage and its methane production via AD.

  15. The production of methane, hydrogen, and organic compounds in ultramafic-hosted hydrothermal vents of the Mid-Atlantic Ridge.

    PubMed

    Konn, C; Charlou, J L; Holm, N G; Mousis, O

    2015-05-01

    Both hydrogen and methane are consistently discharged in large quantities in hydrothermal fluids issued from ultramafic-hosted hydrothermal fields discovered along the Mid-Atlantic Ridge. Considering the vast number of these fields discovered or inferred, hydrothermal fluxes represent a significant input of H2 and CH4 to the ocean. Although there are lines of evidence of their abiogenic formation from stable C and H isotope results, laboratory experiments, and thermodynamic data, neither their origin nor the reaction pathways generating these gases have been fully constrained yet. Organic compounds detected in the fluids may also be derived from abiotic reactions. Although thermodynamics are favorable and extensive experimental work has been done on Fischer-Tropsch-type reactions, for instance, nothing is clear yet about their origin and formation mechanism from actual data. Since chemolithotrophic microbial communities commonly colonize hydrothermal vents, biogenic and thermogenic processes are likely to contribute to the production of H2, CH4, and other organic compounds. There seems to be a consensus toward a mixed origin (both sources and processes) that is consistent with the ambiguous nature of the isotopic data. But the question that remains is, to what proportions? More systematic experiments as well as integrated geochemical approaches are needed to disentangle hydrothermal geochemistry. This understanding is of prime importance considering the implications of hydrothermal H2, CH4, and organic compounds for the ocean global budget, global cycles, and the origin of life.

  16. The Potential Role of Seaweeds in the Natural Manipulation of Rumen Fermentation and Methane Production

    PubMed Central

    Maia, Margarida R. G.; Fonseca, António J. M.; Oliveira, Hugo M.; Mendonça, Carla; Cabrita, Ana R. J.

    2016-01-01

    This study is the first to evaluate the effects of five seaweeds (Ulva sp., Laminaria ochroleuca, Saccharina latissima, Gigartina sp., and Gracilaria vermiculophylla) on gas and methane production and ruminal fermentation parameters when incubated in vitro with two substrates (meadow hay and corn silage) for 24 h. Seaweeds led to lower gas production, with Gigartina sp. presenting the lowest value. When incubated with meadow hay, Ulva sp., Gigartina sp. and G. vermiculophylla decreased methane production, but with corn silage, methane production was only decreased by G. vermiculophylla. With meadow hay, L. ochroleuca and S. latissima promoted similar methane production as the control, but with corn silage, L. ochroleuca increased it. With the exception of S. latissima, all seaweeds promoted similar levels of total volatile fatty acid production. The highest proportion of acetic acid was produced with Ulva sp., G. vermiculophylla, and S. latissima; the highest proportion of butyric acid with the control and L. ochroleuca; and the highest proportion of iso-valeric acid with Gigartina sp. These results reveal the potential of seaweeds to mitigate ruminal methane production and the importance of the basal diet. To efficiently use seaweeds as feed ingredients with nutritional and environmental benefits, more research is required to determine the mechanisms underlying seaweed and substrate interactions. PMID:27572486

  17. The Potential Role of Seaweeds in the Natural Manipulation of Rumen Fermentation and Methane Production

    NASA Astrophysics Data System (ADS)

    Maia, Margarida R. G.; Fonseca, António J. M.; Oliveira, Hugo M.; Mendonça, Carla; Cabrita, Ana R. J.

    2016-08-01

    This study is the first to evaluate the effects of five seaweeds (Ulva sp., Laminaria ochroleuca, Saccharina latissima, Gigartina sp., and Gracilaria vermiculophylla) on gas and methane production and ruminal fermentation parameters when incubated in vitro with two substrates (meadow hay and corn silage) for 24 h. Seaweeds led to lower gas production, with Gigartina sp. presenting the lowest value. When incubated with meadow hay, Ulva sp., Gigartina sp. and G. vermiculophylla decreased methane production, but with corn silage, methane production was only decreased by G. vermiculophylla. With meadow hay, L. ochroleuca and S. latissima promoted similar methane production as the control, but with corn silage, L. ochroleuca increased it. With the exception of S. latissima, all seaweeds promoted similar levels of total volatile fatty acid production. The highest proportion of acetic acid was produced with Ulva sp., G. vermiculophylla, and S. latissima; the highest proportion of butyric acid with the control and L. ochroleuca; and the highest proportion of iso-valeric acid with Gigartina sp. These results reveal the potential of seaweeds to mitigate ruminal methane production and the importance of the basal diet. To efficiently use seaweeds as feed ingredients with nutritional and environmental benefits, more research is required to determine the mechanisms underlying seaweed and substrate interactions.

  18. Methane production through anaerobic digestion of various energy crops grown in sustainable crop rotations.

    PubMed

    Amon, Thomas; Amon, Barbara; Kryvoruchko, Vitaliy; Machmüller, Andrea; Hopfner-Sixt, Katharina; Bodiroza, Vitomir; Hrbek, Regina; Friedel, Jürgen; Pötsch, Erich; Wagentristl, Helmut; Schreiner, Matthias; Zollitsch, Werner

    2007-12-01

    Biogas production is of major importance for the sustainable use of agrarian biomass as renewable energy source. Economic biogas production depends on high biogas yields. The project aimed at optimising anaerobic digestion of energy crops. The following aspects were investigated: suitability of different crop species and varieties, optimum time of harvesting, specific methane yield and methane yield per hectare. The experiments covered 7 maize, 2 winter wheat, 2 triticale varieties, 1 winter rye, and 2 sunflower varieties and 6 variants with permanent grassland. In the course of the vegetation period, biomass yield and biomass composition were measured. Anaerobic digestion was carried out in eudiometer batch digesters. The highest methane yields of 7500-10200 m(N)(3)ha(-1) were achieved from maize varieties with FAO numbers (value for the maturity of the maize) of 300 to 600 harvested at "wax ripeness". Methane yields of cereals ranged from 3200 to 4500 m(N)(3)ha(-1). Cereals should be harvested at "grain in the milk stage" to "grain in the dough stage". With sunflowers, methane yields between 2600 and 4550 m(N)(3)ha(-1) were achieved. There were distinct differences between the investigated sunflower varieties. Alpine grassland can yield 2700-3500 m(N)(3)CH(4)ha(-1). The methane energy value model (MEVM) was developed for the different energy crops. It estimates the specific methane yield from the nutrient composition of the energy crops. Energy crops for biogas production need to be grown in sustainable crop rotations. The paper outlines possibilities for optimising methane yield from versatile crop rotations that integrate the production of food, feed, raw materials and energy. These integrated crop rotations are highly efficient and can provide up to 320 million t COE which is 96% of the total energy demand of the road traffic of the EU-25 (the 25 Member States of the European Union).

  19. Determination of in Situ Rates of Methane Production and Oxidation From Terrestrial Wetlands

    NASA Astrophysics Data System (ADS)

    Shoemaker, J. K.; Schrag, D. P.

    2005-12-01

    Wetlands are responsible for over 70% of non-anthropogenic methane emissions. We present a method, using the δ13C of CO2 in pore water, to obtain the in situ rates of methanogenesis occurring beneath the wetland surface. This method allows us to distinguish methanogenesis from methane oxidation during escape, both of which contribute to the net methane flux. The δ13C of CO2(aq) - the dominant form of DIC in acidic natural waters - reflects the processes occurring at that location modified by transport of gas from surrounding depths. Methane production and oxidation are imprinted in the δ13C signature of the aqueous CO2 with heaviest values at depth resulting from the fractionation associated with methane production. We measured δ13C profiles with depth along with CO2 and CH4 concentrations from Sallie's Fen in Barrington, NH. Although the δ13C profiles varied considerably between locations and seasons, the logarithmic shape of the curves showed that methane production was restricted below a certain depth in the sediment - sometimes as shallow as 30 cm. Using a one-dimensional diffusion-reaction model, we are able to estimate rates of methane oxidation and successfully reproduce features present in the data's seasonal cycle. Features of the data not reproducible by the model indicate the importance of alternate gas transport routes such as ebullition and plant-mediated transport. The model also provides evidence for low-level oxygen availability during the winter-spring transition and narrow zones of very high productivity at depths of 60-70cm during the winter. We suggest that this method provides insight directly into the processes that determine methane fluxes from natural wetlands and has great potential for improving our understanding of the biogeochemistry of these systems.

  20. Production of uracil from methane by a newly isolated Methylomonas sp. SW1.

    PubMed

    Kim, Sangwoo; Lee, Wangjun; Song, Insu; Kwon, Yuhyun; Yun, Seokhun; Park, Soohyun; Cho, Sukhyeong; Oh, Byung-Keun; Oh, Han Bin; Lee, Jinwon

    2016-12-20

    Methane is an abundant, inexpensive one-carbon feedstock and one of the most powerful greenhouse gases. Because it does not compete with food demand, it is considered a promising carbon feedstock for the production of valuable products using methanotrophic bacteria. Here, we isolated a novel methanotrophic bacterium, Methylomonas sp. SW1, from a sewage sample obtained from Wonju City Water Supply Drainage Center, Republic of Korea. The conditions for uracil production by Methylomonas sp. SW1, such as Cu(2+) concentration and temperature were investigated and optimized. As a result, Methylomonas sp. SW1 produced uracil from methane as a sole carbon source with a titer of 2.1mg/L in 84h without genetic engineering under the optimized condition. The results in this study demonstrate the feasibility of using Methylomonas sp. SW1 for the production of uracil from methane. This is the first report of uracil production from gas feedstock by methanotrophic bacteria.

  1. Effect of temperature on methane production from field-scale anaerobic digesters treating dairy manure.

    PubMed

    Arikan, Osman A; Mulbry, Walter; Lansing, Stephanie

    2015-09-01

    Temperature is a critical factor affecting anaerobic digestion because it influences both system heating requirements and methane production. Temperatures of 35-37°C are typically suggested for manure digestion. In temperate climates, digesters require a considerable amount of additional heat energy to maintain temperatures at these levels. In this study, the effects of lower digestion temperatures (22 and 28°C), on the methane production from dairy digesters were evaluated and compared with 35°C using duplicate replicates of field-scale (FS) digesters with a 17-day hydraulic retention time. After acclimation, the FS digesters were operated for 12weeks using solids-separated manure at an organic loading rate (OLR) of 1.4kgVSm(-3)d(-1) and then for 8weeks using separated manure amended with manure solids at an OLR of 2.6kgVSm(-3)d(-1). Methane production values of the FS digesters at 22 and 28°C were about 70% and 87%, respectively, of the values from FS digesters at 35°C. The results suggest that anaerobic digesters treating dairy manure at 28°C were nearly as efficient as digesters operated at 35°C, with 70% of total methane achievable at 22°C. These results are relevant to small farms interested in anaerobic digestion for methane reduction without heat recovery from generators or for methane recovery from covered lagoon digesters.

  2. Biogenic amine production by the wine Lactobacillus brevis IOEB 9809 in systems that partially mimic the gastrointestinal tract stress

    PubMed Central

    2012-01-01

    Background Ingestion of fermented foods containing high levels of biogenic amines (BA) can be deleterious to human health. Less obvious is the threat posed by BA producing organisms contained within the food which, in principle, could form BA after ingestion even if the food product itself does not initially contain high BA levels. In this work we have investigated the production of tyramine and putrescine by Lactobacillus brevis IOEB 9809, of wine origin, under simulated gastrointestinal tract (GIT) conditions. Results An in vitro model that simulates the normal physiological conditions in the human digestive tract, as well as Caco-2 epithelial human cell lines, was used to challenge L. brevis IOEB 9809, which produced both tyramine and putrescine under all conditions tested. In the presence of BA precursors and under mild gastric stress, a correlation between enhancement of bacterial survival and a synchronous transcriptional activation of the tyramine and putrescine biosynthetic pathways was detected. High levels of both BA were observed after exposure of the bacterium to Caco-2 cells. Conclusions L. brevis IOEB 9809 can produce tyramine and putrescine under simulated human digestive tract conditions. The results indicate that BA production may be a mechanism that increases bacterial survival under gastric stress. PMID:23113922

  3. Biogenic gas: Controls, habitats, and resource potential

    SciTech Connect

    Rice, D.D. )

    1993-01-01

    As much as 20 percent of the world's natural-gas resource is estimated to have been generated by the decomposition of organic matter by anaerobic microbes at low temperatures. This gas is commonly referred to as biogenic gas. Most biogenic gas was generated early in the burial history of sediments. Some biogenic gas was also generated in relatively recent geologic time and is associated with groundwater flow. The factors that favor significant generation of biogenic gas are anoxic conditions, low sulfate content, low temperature, abundant organic matter, and sufficient pore space for the microbes to thrive. Conditions beneficial for the accumulation of biogenic gas include stratigraphic or early structural traps, adequate seals, low permeability, low pressure, early dissolution of the gas, and formation of gas hydrates. Rapid sediment deposition is critical to both the generation and the accumulation of biogenic gas generated during the early stage. Biogenic gas is distinguished by its molecular and isotopic composition. The hydrocarbon fraction is generally more than 99 percent methane, and the diagnostic isotopic composition of the methane component is as follows: [delta][sup 13]C values are generally lighter than -55 parts per thousand (permil), and [delta]D values are usually in the range of -150 to -250 permil. This isotopic composition indicates that the methane generally resulted from CO[sub 2] reduction. Significant accumulations of ancient biogenic gas have been discovered in Africa, Asia, Europe, North America, and South America. These accumulations occur in Mississippian and younger rocks, at burial depths as much as 4,600 m. They are associated with a variety of rock types (carbonate, clastic, and coal), and occur in a variety of marine and nonmarine depositional settings generally characterized by rapid deposition. 111 refs., 13 figs., 3 tabs.

  4. Measurements of atmospheric hydrocarbons and biogenic emission fluxes in the Amazon boundary layer

    NASA Technical Reports Server (NTRS)

    Zimmerman, P. R.; Greenberg, J. P.; Westberg, C. E.

    1988-01-01

    Tropospheric mixing ratios of methane, C2-C10 hydrocarbons, and carbon monoxide were measured over the Amazon tropical forest near Manaus, Amazonas, Brazil, in July and August 1985. The measurements, consisting mostly of altitude profiles of these gases, were all made within the atmospheric boundary layer up to an altitude of 1000 m above ground level. Data characterize the diurnal hydrocarbon composition of the boundary layer. Biogenic emissions of isoprene control hydroxyl radical concentrations over the forest. Biogenic emission fluxes of isoprene and terpenes are estimated to be 25,000 micrograms/sq m per day and 5600 micrograms/sq m per day, respectively. This isoprene emission is equivalent to 2 percent of the net primary productivity of the tropical forest. Atmospheric oxidation of biogenic isoprene and terpenes emissions from the Amazon forest may account for daily increases of 8-13 ppb for carbon monoxide in the planetary boundary layer.

  5. Methane sources and production in the northern Cascadia margin gas hydrate system

    USGS Publications Warehouse

    Pohlman, J.W.; Kaneko, M.; Heuer, V.B.; Coffin, R.B.; Whiticar, M.

    2009-01-01

    -enrichment. The magnitude of the 13C-enrichment of CO2 correlates with decreasing sedimentation rates and a diminishing occurrence of stratigraphic gas hydrate. We suggest the decreasing sedimentation rates increase the exposure time of sedimentary organic matter to aerobic and anaerobic degradation, during burial, thereby reducing the availability of metabolizable organic matter available for methane production. This process is reflected in the occurrence and distribution of gas hydrate within the northern Cascadia margin accretionary prism. Our observations are relevant for evaluating methane production and the occurrence of stratigraphic gas hydrate within other convergent margins.

  6. Explicit Microbial Processes to Simulate Methane Production and Oxidation in Wetlands in the GFDL Land Model

    NASA Astrophysics Data System (ADS)

    Smolander, S.; Sulman, B. N.; Shevliakova, E.

    2015-12-01

    Recent observational studies highlighted the need to include explicit treatment of the soil microbial processes into the next generation of Earth System Models (ESMs). These processes shape most soil biogeochemical cycles and control releases of the most potent greenhouses gases carbon dioxide and methane. Currently global ecosystem models usually parameterize methane production as a fraction of soil heterotrophic respiration. This lumps the pathways of several different functional groups of microbes into one production rate, possibly modified by a number of environmental factor multipliers. Methane oxidation is usually more explicitly modeled by Michaelis-Menten kinetics, but if the maximum rate, before environmental multipliers, is a constant parameter, this essentially implies a constant methanotrophic microbe population size. We present an explicit model for wetland soil microbial processes in an ESM context. We introduce a growth and decomposition model for four functional groups of microbes involved in methane production and oxidation, so microbial populations can grow when conditions are favorable and substrate is available. When soil conditions are anoxic, fermenting microbes transform available soil carbon into intermediate substrates, and two different kinds of methanogenic microbes live on their preferred substrates producing methane. Methane is transported through aerobic layers of the soil column, where methanotrophic microbes oxidize part of the methane, and the rest escapes to the atmosphere. We present initial simulations using the new model in the context of existing measurements of methane emissions and microbial populations at the site level, and discuss the implications of including these processes in an ESM. This explicit process model establishes a foundation for improving dynamic ecosystem-climate feedbacks in ESM simulations, and facilitates more detailed experimental verification of wetland biogeochemical processes.

  7. Analysis of methane potentials of steam-exploded wheat straw and estimation of energy yields of combined ethanol and methane production.

    PubMed

    Bauer, Alexander; Bösch, Peter; Friedl, Anton; Amon, Thomas

    2009-06-01

    Agrarian biomass as a renewable energy source can contribute to a considerable CO(2) reduction. The overriding goal of the European Union is to cut energy consumption related greenhouse gas emission in the EU by 20% until the year 2020. This publication aims at optimising the methane production from steam-exploded wheat straw and presents a theoretical estimation of the ethanol and methane potential of straw. For this purpose, wheat straw was pretreated by steam explosion using different time/temperature combinations. Specific methane yields were analyzed according to VDI 4630. Pretreatment of wheat straw by steam explosion significantly increased the methane yield from anaerobic digestion by up to 20% or a maximum of 331 l(N)kg(-1) VS compared to untreated wheat straw. Furthermore, the residual anaerobic digestion potential of methane after ethanol fermentation was determined by enzymatic hydrolysis of pretreated wheat straw using cellulase. Based on the resulting glucose concentration the ethanol yield and the residual sugar available for methane production were calculated. The theoretical maximum ethanol yield of wheat straw was estimated to be 0.249 kg kg(-1) dry matter. The achievable maximum ethanol yield per kg wheat straw dry matter pretreated by steam explosion and enzymatic hydrolysis was estimated to be 0.200 kg under pretreatment conditions of 200 degrees C and 10 min corresponding to 80% of the theoretical maximum. The residual methane yield from straw stillage was estimated to be 183 l(N)kg(-1) wheat straw dry matter. Based on the presented experimental data, a concept is proposed that processes wheat straw for ethanol and methane production. The concept of an energy supply system that provides more than two forms of energy is met by (1) upgrading obtained ethanol to fuel-grade quality and providing methane to CHP plants for the production of (2) electric energy and (3) utility steam that in turn can be used to operate distillation columns in the

  8. Attributing Atmospheric Methane to Anthropogenic Emission Sources.

    PubMed

    Allen, David

    2016-07-19

    Methane is a greenhouse gas, and increases in atmospheric methane concentration over the past 250 years have driven increased radiative forcing of the atmosphere. Increases in atmospheric methane concentration since 1750 account for approximately 17% of increases in radiative forcing of the atmosphere, and that percentage increases by approximately a factor of 2 if the effects of the greenhouse gases produced by the atmospheric reactions of methane are included in the assessment. Because of the role of methane emissions in radiative forcing of the atmosphere, the identification and quantification of sources of methane emissions is receiving increased scientific attention. Methane emission sources include biogenic, geogenic, and anthropogenic sources; the largest anthropogenic sources are natural gas and petroleum systems, enteric fermentation (livestock), landfills, coal mining, and manure management. While these source categories are well-known, there is significant uncertainty in the relative magnitudes of methane emissions from the various source categories. Further, the overall magnitude of methane emissions from all anthropogenic sources is actively debated, with estimates based on source sampling extrapolated to regional or national scale ("bottom-up analyses") differing from estimates that infer emissions based on ambient data ("top-down analyses") by 50% or more. To address the important problem of attribution of methane to specific sources, a variety of new analytical methods are being employed, including high time resolution and highly sensitive measurements of methane, methane isotopes, and other chemical species frequently associated with methane emissions, such as ethane. This Account describes the use of some of these emerging measurements, in both top-down and bottom-up methane emission studies. In addition, this Account describes how data from these new analytical methods can be used in conjunction with chemical mass balance (CMB) methods for source

  9. Addressing biogenic greenhouse gas emissions from hydropower in LCA.

    PubMed

    Hertwich, Edgar G

    2013-09-03

    The ability of hydropower to contribute to climate change mitigation is sometimes questioned, citing emissions of methane and carbon dioxide resulting from the degradation of biogenic carbon in hydropower reservoirs. These emissions are, however, not always addressed in life cycle assessment, leading to a bias in technology comparisons, and often misunderstood. The objective of this paper is to review and analyze the generation of greenhouse gas emissions from reservoirs for the purpose of technology assessment, relating established emission measurements to power generation. A literature review, data collection, and statistical analysis of methane and CO2 emissions are conducted. In a sample of 82 measurements, methane emissions per kWh hydropower generated are log-normally distributed, ranging from micrograms to 10s of kg. A multivariate regression analysis shows that the reservoir area per kWh electricity is the most important explanatory variable. Methane emissions flux per reservoir area are correlated with the natural net primary production of the area, the age of the power plant, and the inclusion of bubbling emissions in the measurement. Even together, these factors fail to explain most of the variation in the methane flux. The global average emissions from hydropower are estimated to be 85 gCO2/kWh and 3 gCH4/kWh, with a multiplicative uncertainty factor of 2. GHG emissions from hydropower can be largely avoided by ceasing to build hydropower plants with high land use per unit of electricity generated.

  10. Microbial and chemical factors influencing methane production in laboratory incubations of low-rank subsurface coals

    USGS Publications Warehouse

    Harris, Stephen H.; Smith, Richard L.; Barker, Charles E.

    2008-01-01

    Lignite and subbituminous coals were investigated for their ability to support microbial methane production in laboratory incubations. Results show that naturally-occurring microorganisms associated with the coals produced substantial quantities of methane, although the factors influencing this process were variable among different samples tested. Methanogenic microbes in two coals from the Powder River Basin, Wyoming, USA, produced 140.5-374.6 mL CH4/kg ((4.5-12.0 standard cubic feet (scf)/ton) in response to an amendment of H2/CO2. The addition of high concentrations (5-10 mM) of acetate did not support substantive methane production under the laboratory conditions. However, acetate accumulated in control incubations where methanogenesis was inhibited, indicating that acetate was produced and consumed during the course of methane production. Acetogenesis from H2/CO2 was evident in these incubations and may serve as a competing metabolic mode influencing the cumulative amount of methane produced in coal. Two low-rank (lignite A) coals from Fort Yukon, Alaska, USA, demonstrated a comparable level of methane production (131.1-284.0 mL CH4/kg (4.2-9.1 scf/ton)) in the presence of an inorganic nutrient amendment, indicating that the source of energy and organic carbon was derived from the coal. The concentration of chloroform-extractable organic matter varied by almost three orders of magnitude among all the coals tested, and appeared to be related to methane production potential. These results indicate that substrate availability within the coal matrix and competition between different groups of microorganisms are two factors that may exert a profound influence on methanogenesis in subsurface coal beds.

  11. Effect of pretreatment by a microbial consortium on methane production of waste paper and cardboard.

    PubMed

    Yuan, Xufeng; Cao, Yanzhuan; Li, Jiajia; Wen, Boting; Zhu, Wanbin; Wang, Xiaofen; Cui, Zongjun

    2012-08-01

    A microbial consortium MC1 was used to pretreat filter paper, office paper, newspaper, and cardboard to enhance methane production. The results of pretreatment indicated that sCOD of hydrolysates of the four substrates increased significantly in the early stage, and peaked on day 7. During pretreatment, ethanol, acetic acid, propionic acid, butyric acid, and glycerol were the predominant volatile organic products in hydrolysates. MC1 had strong degradation ability on the four substrates, and the weight loss of filter paper, office paper, newspaper, and cardboard reached 78.3%, 80.5%, 39.7%, and 49.7%, respectively. The results of anaerobic digestion showed that methane production yields and rates of the four substrates significantly increased after pretreatment. This study is the first attempt to explore the microbial pretreatment method for anaerobic digestion of waste paper and cardboard. Microbial consortium pretreatment could be an effective method for enhancing methane production of waste paper and cardboard into bioenergy.

  12. Evaluation of Dried Sweet Sorghum Stalks as Raw Material for Methane Production

    PubMed Central

    Matsakas, Leonidas; Rova, Ulrika; Christakopoulos, Paul

    2014-01-01

    The potential of utilizing dried sweet sorghum stalks as raw material for anaerobic digestion has been evaluated. Two different treatments were tested, a mild thermal and an enzymatic, alone or in combination. Thermal pretreatment was found to decrease the methane yields, whereas one-step enzymatic treatment resulted in a significant increase of 15.1% comparing to the untreated sweet sorghum. Subsequently, in order to increase the total methane production, the combined effect of enzyme load and I/S on methane yields from sweet sorghum was evaluated by employing response surface methodology. The obtained model showed that the maximum methane yield that could be achieved is 296 mL CH4/g VS at I/S ratio of 0.35 with the addition of 11.12 FPU/g sweet sorghum. PMID:25210715

  13. The carbon isotope biogeochemistry of methane production in anoxic sediments. 1: Field observations

    NASA Technical Reports Server (NTRS)

    Blair, Neal E.; Boehme, Susan E.; Carter, W. Dale, Jr.

    1993-01-01

    The natural abundance C-13/C-12 ratio of methane from anoxic marine and freshwater sediments in temperate climates varies seasonally. Carbon isotopic measurements of the methanogenic precursors, acetate and dissolved inorganic carbon, from the marine sediments of Cape Lookout Bight, North Carolina were used to determine the sources of the seasonal variations at that site. Movement of the methanogenic zone over an isotopic gradient within the dissolved CO2 pool appears to be the dominant control of the methane C-13/C-12 ratio from February to June. The onset of acetoclastic methane-production is a second important controlling process during mid-summer. An apparent temperature dependence on the fractionation factor for CO2-reduction may have a significant influence on the isotopic composition of methane throughout the year.

  14. Methane and fertilizer production from seaweed biomass. Final report

    SciTech Connect

    Betzer, P.R.; Humm, H.J.

    1984-01-01

    It was demonstrated that several varieties of abundant benthic algae indigenous to Tampa Bay (Gracilaria, Hypnea, and Ulva) were readily degradable via anaerobic digestion to methane. The energy yield per unit weight biomass degraded was higher than any previously reported. Given the large masses of readily degradable plants which are annually produced in and around Tampa Bay, the resource is estimated to be at least equivalent to several million gallons of gasoline.

  15. Coalbed methane production base established in Southeast Kansas

    SciTech Connect

    Stoeckinger, W.T.

    1992-04-13

    This paper reports that revenue from coalbed methane gas sales is growing and currently far exceeds that of what little conventional gas is produced in southeastern Kansas. And this only 2-1/2 years after Stroud Oil Properties, Wichita, brought in the first coalbed methane well in the Sycamore Valley in Montgomery County 6 miles north of Independence. Another operator contributing to the success is Conquest Oil, Greeley, Colo. Conquest acquired a lease with 20 old wells near Sycamore, recompleted five of them in Weir coal, and has installed a compressor. It hopes to being selling a combined 300 Mcfd soon. Great Eastern Energy, Denver, reportedly can move 2 MMcfd from its Sycamore Valley holdings. The fever is spreading into Northeast Kansas, where a venture headed by Duncan Energy Co. and Farleigh Oil Properties, also of Denver, plan 12 coalbed methane wildcats. The two companies received in October 1991 from the Kansas Corporation Commission (KCC) a 40 acre well spacing for seven counties and an exclusion from burdensome gas testing procedures. The test procedures are on the books but not applicable to coal gas wells.

  16. Biogenic organic emissions, air quality and climate

    NASA Astrophysics Data System (ADS)

    Guenther, A. B.

    2015-12-01

    Living organisms produce copious amounts of a diverse array of metabolites including many volatile organic compounds that are released into the atmosphere. These compounds participate in numerous chemical reactions that influence the atmospheric abundance of important air pollutants and short-lived climate forcers including organic aerosol, ozone and methane. The production and release of these organics are strongly influenced by environmental conditions including air pollution, temperature, solar radiation, and water availability and they are highly sensitive to stress and extreme events. As a result, releases of biogenic organics to the atmosphere have an impact on, and are sensitive to, air quality and climate leading to potential feedback couplings. Their role in linking air quality and climate is conceptually clear but an accurate quantitative representation is needed for predictive models. Progress towards this goal will be presented including numerical model development and assessments of the predictive capability of the Model of Emission of Gases and Aerosols from Nature (MEGAN). Recent studies of processes controlling the magnitude and variations in biogenic organic emissions will be described and observations of their impact on atmospheric composition will be shown. Recent advances and priorities for future research will be discussed including laboratory process studies, long-term measurements, multi-scale regional studies, global satellite observations, and the development of a next generation model for simulating land-atmosphere chemical exchange.

  17. Seasonal Production and Emission of Methane from Rice Fields, Final Report

    SciTech Connect

    Khalil, M. Aslam K.; Rasmussen,Reinhold A.

    2002-12-03

    B 139 - Methane (CH4) is a greenhouse gas regarded second only to carbon dioxide in its ability to cause global warming. Methane is important because of its relatively fast increase, and also because it is, per molecule, some 60 times more effective than carbon dioxide in causing global warming. The largest present anthropogenic sources of methane are rice fields, cattle and biomass burning. The global emissions from these sources are still not well known. In the middle 1980s there were few available data on methane emissions from rice fields leading to estimates of a global source between 100-280 Tg/yr. Extensive worldwide research during the last decade has shown that the global emissions from rice fields are more likely to be in the range of 30-80Tg/yr. While this work has led to a substantial reduction in the estimated emissions, the uncertainty is still quite large, and seriously affects our ability to include methane in integrated assessments for future climate change and environmental management.China dominated estimates of methane emissions from rice fields because it was, and is, the largest producer of rice, and major increases in rice production had taken place in the country over the last several decades. This report summarizes the work in Sichuan Province, China, in each of the following areas: the design of the experiment; the main results on methane emissions from rice fields, delineating the factors controlling emissions; production of methane in the soil; a survey of water management practices in sample of counties in Sichuan province; and results of ambient measurements including data from the background continental site. B139

  18. Methane emissions from the Amazon Floodplain: Characterization of production and transport

    NASA Astrophysics Data System (ADS)

    Wassmann, R.; Thein, U. G.; Whiticar, M. J.; Rennenburg, H.; Seiler, W.; Junk, W. J.

    1992-03-01

    Methane production, transport and emission in a floodplain lake in central Amazonia were investigated by isotopic studies and gas exchange measurements. Samples of sediment free gas were depleted in δ13CCH4, δ13DCH4,and δ13CCO2 values. The isotopic composition of the sediment free methane clearly demonstrated a methane production by methyl fermentation. This finding was strengthened by the coexisting δ13CCO2 and δ13CCO2 values in the sediment free gas. The flux rates of methane ebullition and diffusion were measured during a complete annual cycle using the static chamber method. Significant differences were observed in the release of methane from individual vegetation types, i.e., phytoplankton, floating grass mats, and flooded forest. Each vegetation type showed a distinct seasonal pattern. The highest ebullition rates (mean value, 69 mg CH4 m-2d-1) were recorded in the flooded forest, covering the higher areas of the floodplains with a long subaerial period. Significantly lower averages of the gas bubble flux were recorded in the permanently aquatic areas of the lake (mean value, 29 mg CH4 m-2d-1) and in the intermediate area with floating grass mats (mean value, 23 mg CH44 m-2d-1. Ebullition was the predominant mechanism for the methane transport from the varzea sediment into the atmosphere with maximum values of up to 200 mg CH4 m-2d-1. The diffusive flux remained below 29 mg CH4 m-2d-1 at all sites throughout the entire annual cycle. The variation of the ebullutive flux was found to determine the spatial and temporal variation of the total methane flux in the varzea. We estimate that ebullition accounts for 80% of the total methane emission from the varzea.

  19. Effects of reduced levels of sulfite in wine production using mixtures with lysozyme and dimethyl dicarbonate on levels of volatile and biogenic amines.

    PubMed

    Ancín-Azpilicueta, Carmen; Jiménez-Moreno, Nerea; Moler, José Antonio; Nieto-Rojo, Rodrigo; Urmeneta, Henar

    2016-10-01

    Sulphur dioxide (SO2) is an important preservative for wine, but its presence in foods can cause allergies and this has given impetus to the research for alternatives. The aim of this study was to reduce levels of sulfite in wine production using mixtures with lysozyme and dimethyl dicarbonate and examine the influence on levels of volatile and biogenic amines. To do so, vinifications were carried out using lysozyme, dimethyl dicarbonate (DMDC) and mixtures of these with SO2 in different concentrations (25 and 50 mg l(-1)). Results were compared with a control vinification with only SO2 (50 mg l(-1)). Mixing low concentrations of SO2 with lysozyme and DMDC reduced the concentration of biogenic amines (histamine, tyramine, putrescine, cadaverine, phenylethylamine + spermidine and spermine). In general, the total concentration of volatile amines (dimethylamine, isopropylamine, isobutylamine, pyrrolidine, ethylamine, diethylamine, amylamine and hexylamine) was higher in the sample fermented only with SO2. The concentrations of amines with secondary amino groups (dimethylamine, diethylamine, pyrrolidine) were higher in the sample only fermented with SO2 than those fermented with DMDC and lysozyme or with a mixture of preservatives. When SO2 was the only preservative in wine, total amine concentration (biogenic and volatile amines) was higher than for the rest of the treatments. Lysozyme by itself, and lysozyme mixed with SO2, both reduced the formation of biogenic amines but given the antioxidant activity of SO2 the use of the preservative mixture seems more advisable.

  20. High-time resolved measurements of biogenic and anthropogenic secondary organic aerosol precursors and products in urban air

    NASA Astrophysics Data System (ADS)

    Flores, Rosa M.; Doskey, Paul V.

    2016-04-01

    Volatile organic compounds (VOCs), which are present in the atmosphere entirely in the gas phase are directly emitted by biogenic (~1089 Tg yr-1) and anthropogenic sources (~185 Tg yr-1). However, the sources and molecular speciation of intermediate VOCs (IVOCs), which are for the most part also present almost entirely in the gas phase, are not well characterized. The VOCs and IVOCs participate in reactions that form ozone and semivolatile OC (SVOC) that partition into the aerosol phase. Formation and evolution of secondary organic aerosol (SOA) are part of a complex dynamic process that depends on the molecular speciation and concentration of VOCs, IVOCs, primary organic aerosol (POA), and the level of oxidants (NO3, OH, O3). The current lack of understanding of OA properties and their impact on radiative forcing, ecosystems, and human health is partly due to limitations of models to predict SOA production on local, regional, and global scales. More accurate forecasting of SOA production requires high-temporal resolution measurement and molecular characterization of SOA precursors and products. For the subject study, the IVOCs and aerosol-phase organic matter were collected using the high-volume sampling technique and were analyzed by multidimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToFMS). The IVOCs included terpenes, terpenoids, n-alkanes, branched alkanes, isoprenoids, alkylbenzenes, cycloalkylbenzenes, PAH, alkyl PAH, and an unresolved complex mixture (UCM). Diurnal variations of OA species containing multiple oxygenated functionalities and selected SOA tracers of isorprene, α-pinene, toluene, cyclohexene, and n-dodecane oxidation were also quantified. The data for SOA precursor and oxidation products presented here will be useful for evaluating the ability of molecular-specific SOA models to forecast SOA production in and downwind of urban areas.

  1. Revising Estimates of the Methane Production Pathway in Peatland Porewater Using Intramolecular Isotopic Analyses of Acetate

    NASA Astrophysics Data System (ADS)

    Thomas, B.; Arthur, M. A.; Freeman, K. H.

    2007-12-01

    Stable isotopic measurements of methane and carbon dioxide are routinely applied to environmental samples to assess the relative importance of methane production by either aceticlastic or hydrogenotrophic methanogenesis. Such estimates rely upon assumptions about isotopic fractionation during methane production and oxidation. Rigorous isotope-based pathway estimates require knowledge of the carbon isotopic composition of both carbon dioxide and acetate. In practice, technical barriers have limited measurements of the isotopic composition of whole acetate in natural samples. Yet, the estimate of whole acetate isotopic values, even when available, may not represent accurately the composition of the methyl carbon, which is, in fact, the precursor to methane. It is exceedingly rare to find carbon isotopic measurements of acetate-methyl in the literature, and, to our knowledge, the d13C of the acetate-methyl precursor to methane has never before been reported from peatland porewater samples. Extremely 13C-depleted methane, -70 permil VPDB, and 13C-enriched carbon dioxide from acidic northern peat bogs are typically interpreted as signatures of hydrogenotrophic methanogenesis. The hypothesized dominance of methane production from hydrogen in acidic bogs contrasts with the vast majority of freshwater wetlands in which aceticlastic methanogenesis dominates. Using a new technique for the online analysis of the intramolecular carbon isotopic composition of acetate in natural samples, we find the acetate-methyl in peat porewaters can be significantly depleted relative to bulk organic matter. In porewater profiles from both winter and summer, acetate is as much as 15 permil depleted relative to bulk carbon. We hypothesize that acetate- methyl isotopic depletion results from conditions that favor autotrophic acetogenesis and subsequent acetate consumption by aceticlastic methanogens. Porewater depth profiles during winter and summer illustrate depth- dependent increases in the

  2. Microbial Methane Production Associated with Carbon Steel Corrosion in a Nigerian Oil Field

    PubMed Central

    Mand, Jaspreet; Park, Hyung S.; Okoro, Chuma; Lomans, Bart P.; Smith, Seun; Chiejina, Leo; Voordouw, Gerrit

    2016-01-01

    Microbially influenced corrosion (MIC) in oil field pipeline systems can be attributed to many different types of hydrogenotrophic microorganisms including sulfate reducers, methanogens and acetogens. Samples from a low temperature oil reservoir in Nigeria were analyzed using DNA pyrotag sequencing. The microbial community compositions of these samples revealed an abundance of anaerobic methanogenic archaea. Activity of methanogens was demonstrated by incubating samples anaerobically in a basal salts medium, in the presence of carbon steel and carbon dioxide. Methane formation was measured in all enrichments and correlated with metal weight loss. Methanogens were prominently represented in pipeline solids samples, scraped from the inside of a pipeline, comprising over 85% of all pyrosequencing reads. Methane production was only witnessed when carbon steel beads were added to these pipeline solids samples, indicating that no methane was formed as a result of degradation of the oil organics present in these samples. These results were compared to those obtained for samples taken from a low temperature oil field in Canada, which had been incubated with oil, either in the presence or in the absence of carbon steel. Again, methanogens present in these samples catalyzed methane production only when carbon steel was present. Moreover, acetate production was also found in these enrichments only in the presence of carbon steel. From these studies it appears that carbon steel, not oil organics, was the predominant electron donor for acetate production and methane formation in these low temperature oil fields, indicating that the methanogens and acetogens found may contribute significantly to MIC. PMID:26793176

  3. Improving methane production from digested manure biofibers by mechanical and thermal alkaline pretreatment.

    PubMed

    Tsapekos, P; Kougias, Panagiotis G; Frison, A; Raga, R; Angelidaki, I

    2016-09-01

    Animal manure digestion is associated with limited methane production, due to the high content in fibers, which are hardly degradable lignocellulosic compounds. In this study, different mechanical and thermal alkaline pretreatment methods were applied to partially degradable fibers, separated from the effluent stream of biogas reactors. Batch and continuous experiments were conducted to evaluate the efficiency of these pretreatments. In batch experiments, the mechanical pretreatment improved the degradability up to 45%. Even higher efficiency was shown by applying thermal alkaline pretreatments, enhancing fibers degradability by more than 4-fold. In continuous experiments, the thermal alkaline pretreatment, using 6% NaOH at 55°C was proven to be the most efficient pretreatment method as the methane production was increased by 26%. The findings demonstrated that the methane production of the biogas plants can be increased by further exploiting the fraction of the digested manure fibers which are discarded in the post-storage tank.

  4. Pretreatment of food waste with high voltage pulse discharge towards methane production enhancement.

    PubMed

    Zou, Lianpei; Ma, Chaonan; Liu, Jianyong; Li, Mingfei; Ye, Min; Qian, Guangren

    2016-12-01

    Anaerobic batch tests were performed to investigate the methane production enhancement and solid transformation rates from food waste (FW) by high voltage pulse discharge (HVPD) pretreatment. The total cumulative methane production with HVPD pretreatment was 134% higher than that of the control. The final volatile solids transformation rates of FW with and without HVPD pretreatment were 54.3% and 32.3%, respectively. Comparison study on HVPD pretreatment with acid, alkali and ultrasonic pretreatments showed that the methane production and COD removal rates of FW pretreated with HVPD were more than 100% higher than the control, but only about 50% higher can be obtained with other pretreatments. HVPD pretreatment could be a promising pretreatment method in the application of energy recovery from FW.

  5. Using Methane 14C to Determine the Origin of the Rapid Methane Rise at the End of the Younger Dryas 11,600 Years Ago: Increased Wetland Production or Methane Hydrates? A Progress Report.

    NASA Astrophysics Data System (ADS)

    Petrenko, V. V.; Severinghaus, J.; Brook, E.; Reeh, N.

    2002-12-01

    The atmospheric methane concentration rose from about 500 parts per billion (ppb) to about 750 ppb over a period of just 150 years at the termination of the Younger Dryas cold period 11,600 years ago, as indicated by Greenland ice core records. The start of this rapid methane increase was synchronous with an even more rapid climate warming -- Greenland ice core nitrogen and argon isotope records indicate that temperatures rose 5 - 10 ?C over just a few decades. There has been considerable debate about the source of this methane rise. Currently, the two main hypotheses attribute the methane rise either to increased bacterial methane production in wetlands, or to the dissociation of large quantities of methane hydrates on the ocean floor. Here we describe the progress of a project whose aim is to determine the origin of this methane rise. Our approach involves using 14C of ancient methane (derived from air bubbles in glacial ice) to determine its source. Methane hydrates are hundreds of thousands to millions of years old, and should contain virtually no 14C, whereas wetland-derived methane will have 14C content identical to that of atmospheric CO2 at the time of production. Obtaining enough ancient methane for a 14C measurement requires very large samples -- about 2 cubic meters. We have been able to locate a site on the western margin of the Greenland ice sheet where large amounts of uncontaminated ancient ice are available at the surface. Furthermore, our measurements of oxygen isotopes in the ice, as well as measurements of methane and oxygen and nitrogen isotopes in the air trapped in this ice have allowed us to date the ice and precisely locate the ice that contains the end-of-Younger-Dryas methane increase signal. Our data also demonstrate that the methane record in this ice is uncontaminated and suitable for methane 14C analysis. During the past year, we also constructed and are testing a device for melting and extracting air from large volumes of glacial ice.

  6. Comparison of Methane Data Products from the TES and AIRS Infrared Sounders

    NASA Astrophysics Data System (ADS)

    Pagano, T. J.; Pagano, T. S.; Worden, J. R.

    2015-12-01

    Methane is the second most powerful greenhouse gas with a highly positive radiative forcing of 0.48 W/m2 (IPCC 2013). Global concentrations of methane have been steadily increasing since 2007 (Bruhwiler 2014), raising concerns about methane's impact on the future global climate. For about the last decade, the Tropospheric Emission Spectrometer (TES) on the Earth Observing System (EOS) Aura spacecraft has been detecting several trace gas species in the troposphere including methane. The goal of this study is to compare TES methane retrievals to that of the Atmospheric Infrared Sounder (AIRS) on the EOS Aqua spacecraft so that scientific investigations may be transferred from TES to AIRS. The two instruments fly in the afternoon constellation (A-Train), providing numerous coincident measurements for comparison. In addition, they also have a similar spectral range, (3.3 to 15.4 µm) for TES (Beer, 2006) and (3.7 to 15.4 µm) for AIRS (Chahine, 2006), making both instruments sensitive to the mid and upper troposphere. This makes them ideal candidates to compare methane data products. However, because AIRS spectral resolution is lower than that of the TES, there may be a difference in vertical sensitivity. In addition, the retrieval techniques and error characteristics are different for the two data sets. The current state of validation for these data products will be presented. To identify conditions in which the data sets agree and dis agree, we present global maps of methane concentrations from monthly level 3 (L3) data products. We also investigate the temporal stability between the two datasets by comparing global zonal averages derived from L3 over the last decade. Finally, we compare L2 retrieval profiles from representative granules in the tropical, mid-latitude and northern latitudes.

  7. Hydrogen and methane production from household solid waste in the two-stage fermentation process.

    PubMed

    Liu, Dawei; Liu, Dapeng; Zeng, Raymond J; Angelidaki, Irini

    2006-06-01

    A two-stage process combined hydrogen and methane production from household solid waste was demonstrated working successfully. The yield of 43 mL H(2)/g volatile solid (VS) added was generated in the first hydrogen production stage and the methane production in the second stage was 500 mL CH(4)/g VS added. This figure was 21% higher than the methane yield from the one-stage process, which was run as control. Sparging of the hydrogen reactor with methane gas resulted in doubling of the hydrogen production. pH was observed as a key factor affecting fermentation pathway in hydrogen production stage. The optimum pH range for hydrogen production in this system was in the range from 5 to 5.5. The short hydraulic retention time (2 days) applied in the first stage was enough to separate acidogenesis from methanogenesis. No additional control for preventing methanogenesis in the first stage was necessary. Furthermore, this study also provided direct evidence in the dynamic fermentation process that, hydrogen production increase was reflected by acetate to butyrate ratio increase in liquid phase.

  8. Is the production of the biogenic amines tyramine and putrescine a species-level trait in enterococci?

    PubMed

    Ladero, Victor; Fernández, María; Calles-Enríquez, Marina; Sánchez-Llana, Esther; Cañedo, Elena; Martín, M Cruz; Alvarez, Miguel A

    2012-05-01

    Biogenic amines (BA) are toxic nitrogenous compounds that can be accumulated in foods via the microbial decarboxylation of certain amino acids. Lactic acid bacteria (LAB) strains belonging to different species and genera have been described as BA producers and are mainly responsible for their synthesis in fermented foods. It is generally accepted that the capacity to produced BAs is strain-dependent. However, the large number of enterococci identified as BA producers suggests that the aminogenic trait may be a species-level characteristic. Enterococcus faecalis, Enterococcus faecium and Enterococcus durans strains of different origin were analysed to determine their capacity to produce tyramine and putrescine. The presence of the genes responsible for this and the identity of their flanking regions were checked by PCR. The results suggest that tyramine biosynthesis is a species-level characteristic in E. faecalis, E. faecium and E. durans. Putrescine synthesis was found to be a species-level trait of E. faecalis, with production occurring via the agmatine deamination pathway. Some E. faecium strains of human origin also produced putrescine; this trait was probably acquired via horizontal gene transfer.

  9. Chamber-Based Estimates of Methane Production in Coastal Estuarine Systems in Southern California

    NASA Astrophysics Data System (ADS)

    Brigham, B.; Lipson, D.; Lai, C.

    2008-12-01

    Wetland systems are believed to produce between 100 - 231 Tg CH4 yr-1 which is roughly 20% of global methane emissions. The uncertainty in methane emissions models stem from the lack of detailed information about methane gas production within regional wetland systems. The aim of this study is to report the range of methane fluxes observed along salinity gradients at two San Diego coastal wetland systems, the Tijuana Estuary (Tijuana River National Estuarine Research Reserve) and the Peñasquitos Lagoon (Torrey Pines State Park Reserve). Soil water samples are used to elucidate factors responsible for the observed variation in methane fluxes. Air samples were subsequently collected from the headspace of a static soil chamber and stored in pre- evacuated vials. Methane concentrations were analyzed within hours after collection by gas chromatography in the laboratory. The chemical and physical properties of the soil, including salinity, pH, redox potential and temperature are measured with a hand-held probe nearby soil collars. The biological properties of the soil, including dissolved organic carbon, nitrate, and ammonia levels are measured from soil water samples in the laboratory. We find that saline sites under direct tidal influence produced methane fluxes ranging from -3.10 to 9.10 (mean 2.18) mg CH4 m-2 day-1. We also find that brackish sites (0.6 to 3.2 ppt in salinity) with fresh water input from residential runoff at the Peñasquitos Lagoon produced methane fluxes ranging from 0.53 to 192.10 (mean 33.34) mg CH4 m-2 day-1. Sampling was done over the course of 5 weeks during August-September of 2008. We hypothesize that the contrasting methane fluxes found between the saline and the brackish sites is due primarily to the different salinity, and in turn sulfate levels found at the two sites. The reduction of sulfate to produce energy is more energetically favorable than the reduction of carbon dioxide to produce methane. Thus the presence of sulfate may act as

  10. Bovine Host Genetic Variation Influences Rumen Microbial Methane Production with Best Selection Criterion for Low Methane Emitting and Efficiently Feed Converting Hosts Based on Metagenomic Gene Abundance

    PubMed Central

    Roehe, Rainer; Dewhurst, Richard J.; Duthie, Carol-Anne; Rooke, John A.; McKain, Nest; Ross, Dave W.; Hyslop, Jimmy J.; Waterhouse, Anthony; Freeman, Tom C.

    2016-01-01

    Methane produced by methanogenic archaea in ruminants contributes significantly to anthropogenic greenhouse gas emissions. The host genetic link controlling microbial methane production is unknown and appropriate genetic selection strategies are not developed. We used sire progeny group differences to estimate the host genetic influence on rumen microbial methane production in a factorial experiment consisting of crossbred breed types and diets. Rumen metagenomic profiling was undertaken to investigate links between microbial genes and methane emissions or feed conversion efficiency. Sire progeny groups differed significantly in their methane emissions measured in respiration chambers. Ranking of the sire progeny groups based on methane emissions or relative archaeal abundance was consistent overall and within diet, suggesting that archaeal abundance in ruminal digesta is under host genetic control and can be used to genetically select animals without measuring methane directly. In the metagenomic analysis of rumen contents, we identified 3970 microbial genes of which 20 and 49 genes were significantly associated with methane emissions and feed conversion efficiency respectively. These explained 81% and 86% of the respective variation and were clustered in distinct functional gene networks. Methanogenesis genes (e.g. mcrA and fmdB) were associated with methane emissions, whilst host-microbiome cross talk genes (e.g. TSTA3 and FucI) were associated with feed conversion efficiency. These results strengthen the idea that the host animal controls its own microbiota to a significant extent and open up the implementation of effective breeding strategies using rumen microbial gene abundance as a predictor for difficult-to-measure traits on a large number of hosts. Generally, the results provide a proof of principle to use the relative abundance of microbial genes in the gastrointestinal tract of different species to predict their influence on traits e.g. human metabolism

  11. Bovine Host Genetic Variation Influences Rumen Microbial Methane Production with Best Selection Criterion for Low Methane Emitting and Efficiently Feed Converting Hosts Based on Metagenomic Gene Abundance.

    PubMed

    Roehe, Rainer; Dewhurst, Richard J; Duthie, Carol-Anne; Rooke, John A; McKain, Nest; Ross, Dave W; Hyslop, Jimmy J; Waterhouse, Anthony; Freeman, Tom C; Watson, Mick; Wallace, R John

    2016-02-01

    Methane produced by methanogenic archaea in ruminants contributes significantly to anthropogenic greenhouse gas emissions. The host genetic link controlling microbial methane production is unknown and appropriate genetic selection strategies are not developed. We used sire progeny group differences to estimate the host genetic influence on rumen microbial methane production in a factorial experiment consisting of crossbred breed types and diets. Rumen metagenomic profiling was undertaken to investigate links between microbial genes and methane emissions or feed conversion efficiency. Sire progeny groups differed significantly in their methane emissions measured in respiration chambers. Ranking of the sire progeny groups based on methane emissions or relative archaeal abundance was consistent overall and within diet, suggesting that archaeal abundance in ruminal digesta is under host genetic control and can be used to genetically select animals without measuring methane directly. In the metagenomic analysis of rumen contents, we identified 3970 microbial genes of which 20 and 49 genes were significantly associated with methane emissions and feed conversion efficiency respectively. These explained 81% and 86% of the respective variation and were clustered in distinct functional gene networks. Methanogenesis genes (e.g. mcrA and fmdB) were associated with methane emissions, whilst host-microbiome cross talk genes (e.g. TSTA3 and FucI) were associated with feed conversion efficiency. These results strengthen the idea that the host animal controls its own microbiota to a significant extent and open up the implementation of effective breeding strategies using rumen microbial gene abundance as a predictor for difficult-to-measure traits on a large number of hosts. Generally, the results provide a proof of principle to use the relative abundance of microbial genes in the gastrointestinal tract of different species to predict their influence on traits e.g. human metabolism

  12. Estimating daily methane production in individual cattle with irregular feed intake patterns from short-term methane emission measurements.

    PubMed

    Cottle, D J; Velazco, J; Hegarty, R S; Mayer, D G

    2015-12-01

    Spot measurements of methane emission rate (n = 18 700) by 24 Angus steers fed mixed rations from GrowSafe feeders were made over 3- to 6-min periods by a GreenFeed emission monitoring (GEM) unit. The data were analysed to estimate daily methane production (DMP; g/day) and derived methane yield (MY; g/kg dry matter intake (DMI)). A one-compartment dose model of spot emission rate v. time since the preceding meal was compared with the models of Wood (1967) and Dijkstra et al. (1997) and the average of spot measures. Fitted values for DMP were calculated from the area under the curves. Two methods of relating methane and feed intakes were then studied: the classical calculation of MY as DMP/DMI (kg/day); and a novel method of estimating DMP from time and size of preceding meals using either the data for only the two meals preceding a spot measurement, or all meals for 3 days prior. Two approaches were also used to estimate DMP from spot measurements: fitting of splines on a 'per-animal per-day' basis and an alternate approach of modelling DMP after each feed event by least squares (using Solver), summing (for each animal) the contributions from each feed event by best-fitting a one-compartment model. Time since the preceding meal was of limited value in estimating DMP. Even when the meal sizes and time intervals between a spot measurement and all feeding events in the previous 72 h were assessed, only 16.9% of the variance in spot emission rate measured by GEM was explained by this feeding information. While using the preceding meal alone gave a biased (underestimate) of DMP, allowing for a longer feed history removed this bias. A power analysis taking into account the sources of variation in DMP indicated that to obtain an estimate of DMP with a 95% confidence interval within 5% of the observed 64 days mean of spot measures would require 40 animals measured over 45 days (two spot measurements per day) or 30 animals measured over 55 days. These numbers suggest that

  13. Production of Excess CO2 relative to methane in peatlands: a new H2 sink

    NASA Astrophysics Data System (ADS)

    Wilson, R.; Woodcroft, B. J.; Varner, R. K.; Tyson, G. W.; Tfaily, M. M.; Sebestyen, S.; Saleska, S. R.; Rogers, K.; Rich, V. I.; McFarlane, K. J.; Kostka, J. E.; Kolka, R. K.; Keller, J.; Iversen, C. M.; Hodgkins, S. B.; Hanson, P. J.; Guilderson, T. P.; Griffiths, N.; de La Cruz, F.; Crill, P. M.; Chanton, J.; Bridgham, S. D.; Barlaz, M.

    2015-12-01

    Methane is generated as the end product of anaerobic organic matter degradation following a series of reaction pathways including fermentation and syntrophy. Along with acetate and CO2, syntrophic reactions generate H2 and are only thermodynamically feasible when coupled to an exothermic reaction that consumes H2. The usual model of organic matter degradation in peatlands has assumed that methanogenesis is that exothermic H2-consuming reaction. If correct, this paradigm should ultimately result in equimolar production of CO2 and methane from the degradation of the model organic compound cellulose: i.e. C6H12O6 à 3CO2 + 3CH4. However, dissolved gas measurement and modeling results from field and incubation experiments spanning peatlands across the northern hemisphere have failed to demonstrate equimolar production of CO2 and methane. Instead, in a flagrant violation of thermodynamics, these studies show a large bias favoring CO2 production over methane generation. In this talk, we will use an array of complementary analytical techniques including FT-IR, cellulose and lignin measurements, 13C-NMR, fluorescence spectroscopy, and ultra-high resolution mass spectrometry to describe organic matter degradation within a peat column and identify the important degradation mechanisms. Hydrogenation was the most common transformation observed in the ultra-high resolution mass spectrometry data. From these results we propose a new mechanism for consuming H2 generated during CO2 production, without concomitant methane formation, consistent with observed high CO2/CH4 ratios. While homoacetogenesis is a known sink for H2 in these systems, this process also consumes CO2 and therefore does not explain the excess CO2 measured in field and incubation samples. Not only does the newly proposed mechanism consume H2 without generating methane, but it also yields enough energy to balance the coupled syntrophic reactions, thereby restoring thermodynamic order. Schematic of organic matter

  14. Sequential parametric optimization of methane production from different sources of forest raw material

    PubMed Central

    Matsakas, Leonidas; Rova, Ulrika; Christakopoulos, Paul

    2015-01-01

    The increase in environmental problems and the shortage of fossil fuels have led to the need for action in the development of sustainable and renewable fuels. Methane is produced through anaerobic digestion of organic materials and is a biofuel with very promising characteristics. The success in using methane as a biofuel has resulted in the operation of several commercial-scale plants and the need to exploit novel materials to be used. Forest biomass can serve as an excellent candidate for use as raw material for anaerobic digestion. During this work, both hardwood and softwood species—which are representative of the forests of Sweden—were used for the production of methane. Initially, when untreated forest materials were used for the anaerobic digestion, the yields obtained were very low, even with the addition of enzymes, reaching a maximum of only 40 mL CH4/g VS when birch was used. When hydrothermal pretreatment was applied, the enzymatic digestibility improved up to 6.7 times relative to that without pretreatment, and the yield of methane reached up to 254 mL CH4/g VS. Then the effect of chemical/enzymatic detoxification was examined, where laccase treatment improved the methane yield from the more harshly pretreated materials while it had no effect on the more mildly pretreated material. Finally, addition of cellulolytic enzymes during the digestion improved the methane yields from spruce and pine, whereas for birch separate saccharification was more beneficial. To achieve high yields in spruce 30 filter paper units (FPU)/g was necessary, whereas 15 FPU/g was enough when pine and birch were used. During this work, the highest methane yields obtained from pine and birch were 179.9 mL CH4/g VS and 304.8 mL CH4/g VS, respectively. For mildly and severely pretreated spruce, the methane yields reached 259.4 mL CH4/g VS and 276.3 mL CH4/g VS, respectively. We have shown that forest material can serve as raw material for efficient production of methane. The

  15. Fungal degradation of coal as a pretreatment for methane production

    USGS Publications Warehouse

    Haider, Rizwan; Ghauri, Muhammad A.; SanFilipo, John R.; Jones, Elizabeth J.; Orem, William H.; Tatu, Calin A.; Akhtar, Kalsoom; Akhtar, Nasrin

    2013-01-01

    Coal conversion technologies can help in taking advantage of huge low rank coal reserves by converting those into alternative fuels like methane. In this regard, fungal degradation of coal can serve as a pretreatment step in order to make coal a suitable substrate for biological beneficiation. A fungal isolate MW1, identified as Penicillium chrysogenum on the basis of fungal ITS sequences, was isolated from a core sample of coal, taken from a well drilled by the US. Geological Survey in Montana, USA. The low rank coal samples, from major coal fields of Pakistan, were treated with MW1 for 7 days in the presence of 0.1% ammonium sulfate as nitrogen source and 0.1% glucose as a supplemental carbon source. Liquid extracts were analyzed through Excitation–Emission Matrix Spectroscopy (EEMS) to obtain qualitative estimates of solubilized coal; these analyses indicated the release of complex organic functionalities. In addition, GC–MS analysis of these extracts confirmed the presence of single ring aromatics, polyaromatic hydrocarbons (PAHs), aromatic nitrogen compounds and aliphatics. Subsequently, the released organics were subjected to a bioassay for the generation of methane which conferred the potential application of fungal degradation as pretreatment. Additionally, fungal-mediated degradation was also prospected for extracting some other chemical entities like humic acids from brown coals with high huminite content especially from Thar, the largest lignite reserve of Pakistan.

  16. Methane production from hydrothermal transformation of siderite to magnetite

    NASA Astrophysics Data System (ADS)

    Muratbayev, T.; Schroeder, C.; Kappler, A.; Haderlein, S.

    2012-12-01

    Mumma et al. (2009) observed a methane (CH4) plume above the Nili Fossae region on Mars, a region rich in carbonate minerals. Morris et al. (2010) suggest this to be (Mg,Fe)-carbonate. McCollom (2003) demonstrated that the hydrothermal transformation of siderite (FeCO3), to magnetite (Fe3O4) produces CH4. This reaction may thus contribute to the formation of methane on Mars, but is also relevant in the context of such diverse topics as diagenesis of Precambrian banded iron formations, sources of prebiotic organic compounds on early Earth, oil and gas accumulations in Earth's crust, or geological sequestration and storage of CO2. However, neither the thermodynamics of this reaction nor the conditions of maximum CH4 yield have been investigated to date. In order to estimate how pressure and temperature influence CH4 yield we derived a thermodynamic model with a numerical solution implemented in MATLAB. We used the equation 12FeCO3 + 2H2O → 4Fe3O4 + 11CO2 + CH4 (Frost et al. 2007) and thermodynamic calculations of the stability field of FeCO3 by Thoms-Keprta et al. (2009) as a template. At 1 bar pressure, the Gibbs energy turns negative (favorable reaction conditions) at a temperature of 200°C. Increasing pressure to 1000 bar changes that temperature to 250°C. An increase in temperature has a larger effect on shifting the Gibbs energy to more negative values. We therefore chose ambient pressure and temperatures of 300°C, 400°C, and 500°C as experimental conditions. We added 100 mg of either natural or synthetic FeCO3 and 25 μL of MilliQ water into long tip Pasteur pipettes inside an anoxic glove box to avoid contamination by free oxygen. The Pasteur pipettes were sealed with butyl stoppers and then melted shut outside of the glove box. The glass capsules were heated for 48 hours in a muffle furnace at 300°C, 400 0C or 5000C. The composition of the gas phase and the formation of methane in particular were analyzed using gas chromatography with a flame

  17. Microalgae to biofuels: life cycle impacts of methane production of anaerobically digested lipid extracted algae.

    PubMed

    Quinn, Jason C; Hanif, Asma; Sharvelle, Sybil; Bradley, Thomas H

    2014-11-01

    This study presents experimental measurements of the biochemical methane production for whole and lipid extracted Nannochloropsis salina. Results show whole microalgae produced 430 cm(3)-CH4 g-volatile solids(-1) (g-VS) (σ=60), 3 times more methane than was produced by the LEA, 140 cm(3)-CH4 g-VS(-1) (σ=30). Results illustrate current anaerobic modeling efforts in microalgae to biofuel assessments are not reflecting the impact of lipid removal. On a systems level, the overestimation of methane production is shown to positively skew the environmental impact of the microalgae to biofuels process. Discussion focuses on a comparison results to those of previous anaerobic digestion studies and quantifies the corresponding change in greenhouse gas emissions of the microalgae to biofuels process based on results from this study.

  18. Methane production potentials, pathways, and communities of methanogens in vertical sediment profiles of river Sitka

    PubMed Central

    Mach, Václav; Blaser, Martin B.; Claus, Peter; Chaudhary, Prem P.; Rulík, Martin

    2015-01-01

    Biological methanogenesis is linked to permanent water logged systems, e.g., rice field soils or lake sediments. In these systems the methanogenic community as well as the pathway of methane formation are well-described. By contrast, the methanogenic potential of river sediments is so far not well-investigated. Therefore, we analyzed (a) the methanogenic potential (incubation experiments), (b) the pathway of methane production (stable carbon isotopes and inhibitor studies), and (c) the methanogenic community composition (terminal restriction length polymorphism of mcrA) in depth profiles of sediment cores of River Sitka, Czech Republic. We found two depth-related distinct maxima for the methanogenic potentials (a) The pathway of methane production was dominated by hydrogenotrophic methanogenesis (b) The methanogenic community composition was similar in all depth layers (c) The main TRFs were representative for Methanosarcina, Methanosaeta, Methanobacterium, and Methanomicrobium species. The isotopic signals of acetate indicated a relative high contribution of chemolithotrophic acetogenesis to the acetate pool. PMID:26052322

  19. Enhancing methane production during the anaerobic digestion of crude glycerol using Japanese cedar charcoal.

    PubMed

    Watanabe, Ryoya; Tada, Chika; Baba, Yasunori; Fukuda, Yasuhiro; Nakai, Yutaka

    2013-12-01

    The use of Japanese cedar charcoal as a support material for microbial attachment could enhance methane production during anaerobic digestion of crude glycerol and wastewater sludge. Methane yield from a charcoal-containing reactor was approximately 1.6 times higher than that from a reactor without charcoal, and methane production was stable over 50 days when the loading rate was 2.17 g chemical oxygen demand (COD) L(-1) d(-1). Examination of microbial communities on the charcoal revealed the presence of Uncultured Desulfovibrio sp. clone V29 and Pelobacter seleniigenes, known as 1,3-propandiol degraders. Hydrogenotrophic methanogens were also detected in the archaeal community on the charcoal. Methanosaeta, Methanoregula, and Methanocellus were present in the charcoal-containing reactor. The concentration of propionate in the charcoal-containing reactor was also lower than that in the control reactor. These results suggest that propionate degradation was enhanced by the consumption of hydrogen by hydrogenotrophic methanogens on the charcoal.

  20. Methane production by treating vinasses from hydrous ethanol using a modified UASB reactor

    PubMed Central

    2012-01-01

    Background A modified laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was used to obtain methane by treating hydrous ethanol vinasse. Vinasses or stillage are waste materials with high organic loads, and a complex composition resulting from the process of alcohol distillation. They must initially be treated with anaerobic processes due to their high organic loads. Vinasses can be considered multipurpose waste for energy recovery and once treated they can be used in agriculture without the risk of polluting soil, underground water or crops. In this sense, treatment of vinasse combines the elimination of organic waste with the formation of methane. Biogas is considered as a promising renewable energy source. The aim of this study was to determine the optimum organic loading rate for operating a modified UASB reactor to treat vinasse generated in the production of hydrous ethanol from sugar cane molasses. Results The study showed that chemical oxygen demand (COD) removal efficiency was 69% at an optimum organic loading rate (OLR) of 17.05 kg COD/m3-day, achieving a methane yield of 0.263 m3/kg CODadded and a biogas methane content of 84%. During this stage, effluent characterization presented lower values than the vinasse, except for potassium, sulfide and ammonia nitrogen. On the other hand, primers used to amplify the 16S-rDNA genes for the domains Archaea and Bacteria showed the presence of microorganisms which favor methane production at the optimum organic loading rate. Conclusions The modified UASB reactor proposed in this study provided a successful treatment of the vinasse obtained from hydrous ethanol production. Methanogen groups (Methanobacteriales and Methanosarcinales) detected by PCR during operational optimum OLR of the modified UASB reactor, favored methane production. PMID:23167984

  1. Isotopic evidence for biogenic molecular hydrogen production in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Walter, S.; Kock, A.; Steinhoff, T.; Fiedler, B.; Fietzek, P.; Kaiser, J.; Krol, M. C.; Popa, M. E.; Chen, Q.; Tanhua, T.; Röckmann, T.

    2015-10-01

    Oceans are a net source of molecular hydrogen (H2) to the atmosphere. The production of marine H2 is assumed to be mainly biological by N2 fixation, but photochemical pathways are also discussed. We present measurements of mole fraction and isotopic composition of dissolved and atmospheric H2 from the southern and northern Atlantic between 2008 and 2010. In total almost 400 samples were taken during five cruises along a transect between Punta Arenas (Chile) and Bremerhaven (Germany), as well as at the coast of Mauretania. The isotopic source signatures of dissolved H2 extracted from surface water are highly deuterium-depleted and correlate negatively with temperature, showing δD values of (-629 ± 54) ‰ for water temperatures at (27 ± 3) °C and (-249 ± 88) ‰ below (19 ± 1) °C. The results for warmer water masses are consistent with biological production of H2. This is the first time that marine H2 excess has been directly attributed to biological production by isotope measurements. However, the isotope values obtained in the colder water masses indicate that beside possible biological production a significant different source should be considered. The atmospheric measurements show distinct differences between both hemispheres as well as between seasons. Results from the global chemistry transport model TM5 reproduce the measured H2 mole fractions and isotopic composition well. The climatological global oceanic emissions from the GEMS database are in line with our data and previously published flux calculations. The good agreement between measurements and model results demonstrates that both the magnitude and the isotopic signature of the main components of the marine H2 cycle are in general adequately represented in current atmospheric models despite a proposed source different from biological production or a substantial underestimation of nitrogen fixation by several authors.

  2. Isotopic evidence for biogenic molecular hydrogen production in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Walter, S.; Kock, A.; Steinhoff, T.; Fiedler, B.; Fietzek, P.; Kaiser, J.; Krol, M.; Popa, M. E.; Chen, Q.; Tanhua, T.; Röckmann, T.

    2016-01-01

    Oceans are a net source of molecular hydrogen (H2) to the atmosphere. The production of marine H2 is assumed to be mainly biological by N2 fixation, but photochemical pathways are also discussed. We present measurements of mole fraction and isotopic composition of dissolved and atmospheric H2 from the southern and northern Atlantic between 2008 and 2010. In total almost 400 samples were taken during 5 cruises along a transect between Punta Arenas (Chile) and Bremerhaven (Germany), as well as at the coast of Mauritania.

    The isotopic source signatures of dissolved H2 extracted from surface water are highly deuterium-depleted and correlate negatively with temperature, showing δD values of (-629 ± 54) ‰ for water temperatures at (27 ± 3) °C and (-249 ± 88) ‰ below (19 ± 1) °C. The results for warmer water masses are consistent with the biological production of H2. This is the first time that marine H2 excess has been directly attributed to biological production by isotope measurements. However, the isotope values obtained in the colder water masses indicate that beside possible biological production, a significant different source should be considered.

    The atmospheric measurements show distinct differences between both hemispheres as well as between seasons. Results from the global chemistry transport model TM5 reproduce the measured H2 mole fractions and isotopic composition well. The climatological global oceanic emissions from the GEMS database are in line with our data and previously published flux calculations. The good agreement between measurements and model results demonstrates that both the magnitude and the isotopic signature of the main components of the marine H2 cycle are in general adequately represented in current atmospheric models despite a proposed source different from biological production or a substantial underestimation of nitrogen fixation by several authors.

  3. Optimization of process parameters for production of volatile fatty acid, biohydrogen and methane from anaerobic digestion.

    PubMed

    Khan, M A; Ngo, H H; Guo, W S; Liu, Y; Nghiem, L D; Hai, F I; Deng, L J; Wang, J; Wu, Y

    2016-11-01

    The anaerobic digestion process has been primarily utilized for methane containing biogas production over the past few years. However, the digestion process could also be optimized for producing volatile fatty acids (VFAs) and biohydrogen. This is the first review article that combines the optimization approaches for all three possible products from the anaerobic digestion. In this review study, the types and configurations of the bioreactor are discussed for each type of product. This is followed by a review on optimization of common process parameters (e.g. temperature, pH, retention time and organic loading rate) separately for the production of VFA, biohydrogen and methane. This review also includes additional parameters, treatment methods or special additives that wield a significant and positive effect on production rate and these products' yield.

  4. Scale-up of the production of highly reactive biogenic magnetite nanoparticles using Geobacter sulfurreducens.

    PubMed

    Byrne, J M; Muhamadali, H; Coker, V S; Cooper, J; Lloyd, J R

    2015-06-06

    Although there are numerous examples of large-scale commercial microbial synthesis routes for organic bioproducts, few studies have addressed the obvious potential for microbial systems to produce inorganic functional biomaterials at scale. Here we address this by focusing on the production of nanoscale biomagnetite particles by the Fe(III)-reducing bacterium Geobacter sulfurreducens, which was scaled up successfully from laboratory- to pilot plant-scale production, while maintaining the surface reactivity and magnetic properties which make this material well suited to commercial exploitation. At the largest scale tested, the bacterium was grown in a 50 l bioreactor, harvested and then inoculated into a buffer solution containing Fe(III)-oxyhydroxide and an electron donor and mediator, which promoted the formation of magnetite in under 24 h. This procedure was capable of producing up to 120 g of biomagnetite. The particle size distribution was maintained between 10 and 15 nm during scale-up of this second step from 10 ml to 10 l, with conserved magnetic properties and surface reactivity; the latter demonstrated by the reduction of Cr(VI). The process presented provides an environmentally benign route to magnetite production and serves as an alternative to harsher synthetic techniques, with the clear potential to be used to produce kilogram to tonne quantities.

  5. Insights into biogenic and chemical production of inorganic nanomaterials and nanostructures.

    PubMed

    Faramarzi, Mohammad Ali; Sadighi, Armin

    2013-03-01

    The synthesis of inorganic nanomaterials and nanostructures by the means of diverse physical, chemical, and biological principles has been developed in recent decades. The nanoscale materials and structures creation continue to be an active area of researches due to the exciting properties of the resulting nanomaterials and their innovative applications. Despite physical and chemical approaches which have been used for a long time to produce nanomaterials, biological resources as green candidates that can replace old production methods have been focused in recent years to generate various inorganic nanoparticles (NPs) or other nanoscale structures. Cost-effective, eco-friendly, energy efficient, and nontoxic produced nanomaterials using diverse biological entities have been received increasing attention in the last two decades in contrast to physical and chemical methods owe using toxic solvents, generate unwanted by-products, and high energy consumption which restrict the popularity of these ways employed in nanometric science and engineering. In this review, the biosynthesis of gold, silver, gold-silver alloy, magnetic, semiconductor nanocrystals, silica, zirconia, titania, palladium, bismuth, selenium, antimony sulfide, and platinum NPs, using bacteria, actinomycetes, fungi, yeasts, plant extracts and also informational bio-macromolecules including proteins, polypeptides, DNA, and RNA have been reported extensively to mention the current status of the biological inorganic nanomaterial production. In other hand, two well-known wet chemical techniques, namely chemical reduction and sol-gel methods, used to produce various types of nanocrystalline powders, metal oxides, and hybrid organic-inorganic nanomaterials have presented.

  6. Reactions between vanadium ions and biogenic reductants of tunicates: Spectroscopic probing for complexation and redox products in vitro

    SciTech Connect

    Ryan, D.E.; Grant, K.B.; Nakanishi, K.

    1996-07-02

    Several species of marine tunicates store oxygen-sensitive V{sup III} in blood cells. A sensitive colorimetric V{sup III} assay was used t survey the leading candidates for the native reducing agent of vanadate in tunicates (i.e., An-type tunichromes, glutathione, NADPH, and H{sub 2}S) in reactions with V{sup V} or V{sup IV} ions under anaerobic, aqueous conditions at acidic or neutral pH. Except for the case of An-1 and V{sup V} ions in pH 7 buffer, the assay results for the biogenic reducing agents clearly showed that appreciable quantities of V{sup III} products were not generated under the conditions tested. Therefore, the assay results place new limits on hypothetical mechanisms of V{sup III} formation in vivo. For reactions between An-1 and V{sup V} ions in pH 7 buffer, low levels of V{sup III} products could not be ruled out because of an interfering peak in the colorimetric assays. For similar reactions between V{sup V} ions and An-1, or an An-1,2 mixture, in mildly to moderately basic media, the product mixtures precipitated as greenish black solids. Analyses of the precipitated V/An mixtures using vanadium K-edge X-ray absorption spectroscopy (XAS) showed that the major products were tris(catecholate)-type V{sup IV} complexes (65 {plus_minus} 6%) and bis(catecholate)-type V{sup IV}O complexes (20 {plus_minus} 4%). XAS analysis of the V/An-1 product mixture also provided evidence of a minor V{sup III} component (9 {plus_minus} 5% of total V), notable for possible relevance to tunicate biochemistry. The combined results of XAS studies, spectrophotometric studies, and EPR studies consistently establish that reactions between tunichromes (Mm-1 or An-1) and V{sup V} ions generate predominantly V{sup IV}-tunichrome complexes in neutral to moderately basic aqueous media. 53 refs., 4 figs., 3 tabs.

  7. Evidence for methane production by marine algae (Emiliana huxleyi) and its implication for the methane paradox in oxic waters

    NASA Astrophysics Data System (ADS)

    Lenhart, K.; Klintzsch, T.; Langer, G.; Nehrke, G.; Bunge, M.; Schnell, S.; Keppler, F.

    2015-12-01

    Methane (CH4), an important greenhouse gas that affects radiation balance and consequently the earth's climate, still has uncertainties in its sinks and sources. The world's oceans are considered to be a source of CH4 to the atmosphere, although the biogeochemical processes involved in its formation are not fully understood. Several recent studies provided strong evidence of CH4 production in oxic marine and freshwaters but its source is still a topic of debate. Studies of CH4 dynamics in surface waters of oceans and large lakes have concluded that pelagic CH4 supersaturation cannot be sustained either by lateral inputs from littoral or benthic inputs alone. However, frequently regional and temporal oversaturation of surface waters occurs. This comprises the observation of a CH4 oversaturating state within the surface mixed layer, sometimes also termed the "oceanic methane paradox". In this study we considered marine algae as a possible direct source of CH4. Therefore, the coccolithophore Emiliania huxleyi was grown under controlled laboratory conditions and supplemented with two 13C-labelled carbon substrates, namely bicarbonate and a position-specific 13C-labelled methionine (R-S-13CH3). The CH4 production was 0.7 μg POC g-1 d-1, or 30 ng g-1 POC h-1. After supplementation of the cultures with the 13C labelled substrate, the isotope label was observed in headspace-CH4. Moreover, the absence of methanogenic archaea within the algal culture and the oxic conditions during CH4 formation suggest that marine algae such as Emiliania huxleyi contribute to the observed spatial and temporal restricted CH4 oversaturation in ocean surface waters.

  8. Modelling Methane Production and Sulfate Reduction in Anaerobic Granular Sludge Reactor with Ethanol as Electron Donor

    NASA Astrophysics Data System (ADS)

    Sun, Jing; Dai, Xiaohu; Wang, Qilin; Pan, Yuting; Ni, Bing-Jie

    2016-10-01

    In this work, a mathematical model based on growth kinetics of microorganisms and substrates transportation through biofilms was developed to describe methane production and sulfate reduction with ethanol being a key electron donor. The model was calibrated and validated using experimental data from two case studies conducted in granule-based Upflow Anaerobic Sludge Blanket reactors. The results suggest that the developed model could satisfactorily describe methane and sulfide productions as well as ethanol and sulfate removals in both systems. The modeling results reveal a stratified distribution of methanogenic archaea, sulfate-reducing bacteria and fermentative bacteria in the anaerobic granular sludge and the relative abundances of these microorganisms vary with substrate concentrations. It also indicates sulfate-reducing bacteria can successfully outcompete fermentative bacteria for ethanol utilization when COD/SO42‑ ratio reaches 0.5. Model simulation suggests that an optimal granule diameter for the maximum methane production efficiency can be achieved while the sulfate reduction efficiency is not significantly affected by variation in granule size. It also indicates that the methane production and sulfate reduction can be affected by ethanol and sulfate loading rates, and the microbial community development stage in the reactor, which provided comprehensive insights into the system for its practical operation.

  9. Enhancement of methane production from co-digestion of chicken manure with agricultural wastes.

    PubMed

    Abouelenien, Fatma; Namba, Yuzaburo; Kosseva, Maria R; Nishio, Naomichi; Nakashimada, Yutaka

    2014-05-01

    The potential for methane production from semi-solid chicken manure (CM) and mixture of agricultural wastes (AWS) in a co-digestion process has been experimentally evaluated at thermophilic and mesophilic temperatures. To the best of author(')s knowledge, it is the first time that CM is co-digested with mixture of AWS consisting of coconut waste, cassava waste, and coffee grounds. Two types of anaerobic digestion processes (AD process) were used, process 1 (P1) using fresh CM (FCM) and process 2 (P2) using treated CM (TCM), ammonia stripped CM, were conducted. Methane production in P1 was increased by 93% and 50% compared to control (no AWS added) with maximum methane production of 502 and 506 mL g(-1)VS obtained at 55°C and 35°C, respectively. Additionally, 42% increase in methane production was observed with maximum volume of 695 mL g(-1)VS comparing P2 test with P2 control under 55°C. Ammonia accumulation was reduced by 39% and 32% in P1 and P2 tests.

  10. Nanostructural control of methane release in kerogen and its implications to wellbore production decline

    SciTech Connect

    Ho, Tuan Anh; Criscenti, Louise J.; Wang, Yifeng

    2016-06-16

    In spite of the massive success of shale gas production in the US in the last few decades there are still major concerns with the steep decline in wellbore production and the large uncertainty in a long-term projection of decline curves. A reliable projection must rely on a mechanistic understanding of methane release in shale matrix–a limiting step in shale gas extraction. Here we show that methane release in nanoporous kerogen matrix is characterized by fast release of pressurized free gas (accounting for ~30–47% recovery) followed by slow release of adsorbed gas as the gas pressure decreases, and we use molecular simulations to demonstrate it. The first stage is driven by the gas pressure gradient while the second stage is controlled by gas desorption and diffusion. We further show that diffusion of all methane in nanoporous kerogen behaves differently from the bulk phase, with much smaller diffusion coefficients. The MD simulations also indicate that a significant fraction (3–35%) of methane deposited in kerogen can potentially become trapped in isolated nanopores and thus not recoverable. Finally, our results shed a new light on mechanistic understanding gas release and production decline in unconventional reservoirs. The long-term production decline appears controlled by the second stage of gas release.

  11. Nanostructural control of methane release in kerogen and its implications to wellbore production decline

    NASA Astrophysics Data System (ADS)

    Ho, Tuan Anh; Criscenti, Louise J.; Wang, Yifeng

    2016-06-01

    Despite massive success of shale gas production in the US in the last few decades there are still major concerns with the steep decline in wellbore production and the large uncertainty in a long-term projection of decline curves. A reliable projection must rely on a mechanistic understanding of methane release in shale matrix–a limiting step in shale gas extraction. Using molecular simulations, we here show that methane release in nanoporous kerogen matrix is characterized by fast release of pressurized free gas (accounting for ~30–47% recovery) followed by slow release of adsorbed gas as the gas pressure decreases. The first stage is driven by the gas pressure gradient while the second stage is controlled by gas desorption and diffusion. We further show that diffusion of all methane in nanoporous kerogen behaves differently from the bulk phase, with much smaller diffusion coefficients. The MD simulations also indicate that a significant fraction (3–35%) of methane deposited in kerogen can potentially become trapped in isolated nanopores and thus not recoverable. Our results shed a new light on mechanistic understanding gas release and production decline in unconventional reservoirs. The long-term production decline appears controlled by the second stage of gas release.

  12. Nanostructural control of methane release in kerogen and its implications to wellbore production decline

    DOE PAGES

    Ho, Tuan Anh; Criscenti, Louise J.; Wang, Yifeng

    2016-06-16

    In spite of the massive success of shale gas production in the US in the last few decades there are still major concerns with the steep decline in wellbore production and the large uncertainty in a long-term projection of decline curves. A reliable projection must rely on a mechanistic understanding of methane release in shale matrix–a limiting step in shale gas extraction. Here we show that methane release in nanoporous kerogen matrix is characterized by fast release of pressurized free gas (accounting for ~30–47% recovery) followed by slow release of adsorbed gas as the gas pressure decreases, and we usemore » molecular simulations to demonstrate it. The first stage is driven by the gas pressure gradient while the second stage is controlled by gas desorption and diffusion. We further show that diffusion of all methane in nanoporous kerogen behaves differently from the bulk phase, with much smaller diffusion coefficients. The MD simulations also indicate that a significant fraction (3–35%) of methane deposited in kerogen can potentially become trapped in isolated nanopores and thus not recoverable. Finally, our results shed a new light on mechanistic understanding gas release and production decline in unconventional reservoirs. The long-term production decline appears controlled by the second stage of gas release.« less

  13. Hourly methane production in finishing steers fed at different levels of dry matter intake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methane (CH4) loss from finishing cattle is important as it represents an energy loss that could be used for maintenance and growth, and CH4 is a greenhouse gas with a global warming potential 21 to 25 times that of CO2. Our objectives were to determine hourly CH4 production from growing cattle fed...

  14. Zero valent iron simultaneously enhances methane production and sulfate reduction in anaerobic granular sludge reactors.

    PubMed

    Liu, Yiwen; Zhang, Yaobin; Ni, Bing-Jie

    2015-05-15

    Zero valent iron (ZVI) packed anaerobic granular sludge reactors have been developed for improved anaerobic wastewater treatment. In this work, a mathematical model is developed to describe the enhanced methane production and sulfate reduction in anaerobic granular sludge reactors with the addition of ZVI. The model is successfully calibrated and validated using long-term experimental data sets from two independent ZVI-enhanced anaerobic granular sludge reactors with different operational conditions. The model satisfactorily describes the chemical oxygen demand (COD) removal, sulfate reduction and methane production data from both systems. Results show ZVI directly promotes propionate degradation and methanogenesis to enhance methane production. Simultaneously, ZVI alleviates the inhibition of un-dissociated H2S on acetogens, methanogens and sulfate reducing bacteria (SRB) through buffering pH (Fe(0) + 2H(+) = Fe(2+) + H2) and iron sulfide precipitation, which improve the sulfate reduction capacity, especially under deterioration conditions. In addition, the enhancement of ZVI on methane production and sulfate reduction occurs mainly at relatively low COD/ [Formula: see text] ratio (e.g., 2-4.5) rather than high COD/ [Formula: see text] ratio (e.g., 16.7) compared to the reactor without ZVI addition. The model proposed in this work is expected to provide support for further development of a more efficient ZVI-based anaerobic granular system.

  15. Heat production, respiratory quotient, and methane loss subsequent to LPS challenge in beef heifers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Respiration calorimetry was used to measure energy utilization during an acute phase response (APR) to lipopolysaccharide (LPS). Eight Angus heifers (208 +/- 29.2 kg) were randomly assigned to one of two calorimeters in four 2-day periods for measurement of heat production (HP), methane (CH4), and r...

  16. Modelling Methane Production and Sulfate Reduction in Anaerobic Granular Sludge Reactor with Ethanol as Electron Donor

    PubMed Central

    Sun, Jing; Dai, Xiaohu; Wang, Qilin; Pan, Yuting; Ni, Bing-Jie

    2016-01-01

    In this work, a mathematical model based on growth kinetics of microorganisms and substrates transportation through biofilms was developed to describe methane production and sulfate reduction with ethanol being a key electron donor. The model was calibrated and validated using experimental data from two case studies conducted in granule-based Upflow Anaerobic Sludge Blanket reactors. The results suggest that the developed model could satisfactorily describe methane and sulfide productions as well as ethanol and sulfate removals in both systems. The modeling results reveal a stratified distribution of methanogenic archaea, sulfate-reducing bacteria and fermentative bacteria in the anaerobic granular sludge and the relative abundances of these microorganisms vary with substrate concentrations. It also indicates sulfate-reducing bacteria can successfully outcompete fermentative bacteria for ethanol utilization when COD/SO42− ratio reaches 0.5. Model simulation suggests that an optimal granule diameter for the maximum methane production efficiency can be achieved while the sulfate reduction efficiency is not significantly affected by variation in granule size. It also indicates that the methane production and sulfate reduction can be affected by ethanol and sulfate loading rates, and the microbial community development stage in the reactor, which provided comprehensive insights into the system for its practical operation. PMID:27731395

  17. Short chain fatty acid production and glucose responses by methane producers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fermentation by gut microbiota has been linked to physiologic responses in the host. Methanogenic gut bacteria may remove more carbon from indigestible food matrices especially poorly digested carbohydrates. We sought to assess the effects of methane production on short chain fatty acid (SCFA) con...

  18. The presence of hydrogenotrophic methanogens in the inoculum improves methane gas production in microbial electrolysis cells

    PubMed Central

    Siegert, Michael; Li, Xiu-Fen; Yates, Matthew D.; Logan, Bruce E.

    2015-01-01

    High current densities in microbial electrolysis cells (MECs) result from the predominance of various Geobacter species on the anode, but it is not known if archaeal communities similarly converge to one specific genus. MECs were examined here on the basis of maximum methane production and current density relative to the inoculum community structure. We used anaerobic digester (AD) sludge dominated by acetoclastic Methanosaeta, and an anaerobic bog sediment where hydrogenotrophic methanogens were detected. Inoculation using solids to medium ratio of 25% (w/v) resulted in the highest methane production rates (0.27 mL mL−1 cm−2, gas volume normalized by liquid volume and cathode projected area) and highest peak current densities (0.5 mA cm−2) for the bog sample. Methane production was independent of solid to medium ratio when AD sludge was used as the inoculum. 16S rRNA gene community analysis using pyrosequencing and quantitative PCR confirmed the convergence of Archaea to Methanobacterium and Methanobrevibacter, and of Bacteria to Geobacter, despite their absence in AD sludge. Combined with other studies, these findings suggest that Archaea of the hydrogenotrophic genera Methanobacterium and Methanobrevibacter are the most important microorganisms for methane production in MECs and that their presence in the inoculum improves the performance. PMID:25642216

  19. Assessment of Methane Emissions from Oil and Gas Production Pads using Mobile Measurements

    EPA Science Inventory

    Journal Article Abstract --- "A mobile source inspection approach called OTM 33A was used to quantify short-term methane emission rates from 218 oil and gas production pads in Texas, Colorado, and Wyoming from 2010 to 2013. The emission rates were log-normally distributed with ...

  20. Effect of temperature on methane production from field-scale anaerobic digesters treating dairy manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temperature is a critical factor affecting anaerobic digestion because it influences both system heating requirements and methane production. Temperatures of 35-37°C are typically suggested for manure digestion, yet in temperate climate digesters, require a considerable amount of additional heat en...

  1. Nanostructural control of methane release in kerogen and its implications to wellbore production decline

    PubMed Central

    Ho, Tuan Anh; Criscenti, Louise J.; Wang, Yifeng

    2016-01-01

    Despite massive success of shale gas production in the US in the last few decades there are still major concerns with the steep decline in wellbore production and the large uncertainty in a long-term projection of decline curves. A reliable projection must rely on a mechanistic understanding of methane release in shale matrix–a limiting step in shale gas extraction. Using molecular simulations, we here show that methane release in nanoporous kerogen matrix is characterized by fast release of pressurized free gas (accounting for ~30–47% recovery) followed by slow release of adsorbed gas as the gas pressure decreases. The first stage is driven by the gas pressure gradient while the second stage is controlled by gas desorption and diffusion. We further show that diffusion of all methane in nanoporous kerogen behaves differently from the bulk phase, with much smaller diffusion coefficients. The MD simulations also indicate that a significant fraction (3–35%) of methane deposited in kerogen can potentially become trapped in isolated nanopores and thus not recoverable. Our results shed a new light on mechanistic understanding gas release and production decline in unconventional reservoirs. The long-term production decline appears controlled by the second stage of gas release. PMID:27306967

  2. Effect of the chlortetracycline addition method on methane production from the anaerobic digestion of swine wastewater.

    PubMed

    Huang, Lu; Wen, Xin; Wang, Yan; Zou, Yongde; Ma, Baohua; Liao, Xindi; Liang, Juanboo; Wu, Yinbao

    2014-10-01

    Effects of antibiotic residues on methane production in anaerobic digestion are commonly studied using the following two antibiotic addition methods: (1) adding manure from animals that consume a diet containing antibiotics, and (2) adding antibiotic-free animal manure spiked with antibiotics. This study used chlortetracycline (CTC) as a model antibiotic to examine the effects of the antibiotic addition method on methane production in anaerobic digestion under two different swine wastewater concentrations (0.55 and 0.22mg CTC/g dry manure). The results showed that CTC degradation rate in which manure was directly added at 0.55mg CTC/g (HSPIKE treatment) was lower than the control values and the rest of the treatment groups. Methane production from the HSPIKE treatment was reduced (p<0.05) by 12% during the whole experimental period and 15% during the first 7days. The treatments had no significant effect on the pH and chemical oxygen demand value of the digesters, and the total nitrogen of the 0.55mg CTC/kg manure collected from mediated swine was significantly higher than the other values. Therefore, different methane production under different antibiotic addition methods might be explained by the microbial activity and the concentrations of antibiotic intermediate products and metabolites. Because the primary entry route of veterinary antibiotics into an anaerobic digester is by contaminated animal manure, the most appropriate method for studying antibiotic residue effects on methane production may be using manure from animals that are given a particular antibiotic, rather than adding the antibiotic directly to the anaerobic digester.

  3. Net biogenic silica production and the contribution of diatoms to new production and organic matter export in the Costa Rica Dome ecosystem

    PubMed Central

    Krause, Jeffrey W.; Stukel, Michael R.; Taylor, Andrew G.; Taniguchi, Darcy A. A.; De Verneil, Alain; Landry, Michael R.

    2016-01-01

    We determined the net rate of biogenic silica (bSiO2) production and estimated the diatom contribution to new production and organic matter export in the Costa Rica Dome during summer 2010. The shallow thermocline significantly reduces bSiO2 dissolution rates below the mixed layer, leading to significant enhancement of bSiO2 relative to organic matter (silicate-pump condition). This may explain why deep export of bSiO2 in this region is elevated by an order of magnitude relative to comparable systems. Diatom carbon, relative to autotrophic carbon, was low (<3%); however, the contribution of diatoms to new production averaged 3 and 13% using independent approaches. The 4-old discrepancy between methods may be explained by a low average C:Si ratio (∼1.4) for the net produced diatom C relative to the net produced bSiO2. We speculate that this low production ratio is not the result of reduced C, but may arise from a significant contribution of non-diatom silicifying organisms to bSiO2 production. The contribution of diatoms to organic matter export was minor (5.7%). These results, and those of the broader project, suggest substantial food-web transformation of diatom organic matter in the euphotic zone, which creates enriched bSiO2 relative to organic matter within the exported material. PMID:27275026

  4. Net biogenic silica production and the contribution of diatoms to new production and organic matter export in the Costa Rica Dome ecosystem.

    PubMed

    Krause, Jeffrey W; Stukel, Michael R; Taylor, Andrew G; Taniguchi, Darcy A A; De Verneil, Alain; Landry, Michael R

    2016-03-01

    We determined the net rate of biogenic silica (bSiO2) production and estimated the diatom contribution to new production and organic matter export in the Costa Rica Dome during summer 2010. The shallow thermocline significantly reduces bSiO2 dissolution rates below the mixed layer, leading to significant enhancement of bSiO2 relative to organic matter (silicate-pump condition). This may explain why deep export of bSiO2 in this region is elevated by an order of magnitude relative to comparable systems. Diatom carbon, relative to autotrophic carbon, was low (<3%); however, the contribution of diatoms to new production averaged 3 and 13% using independent approaches. The 4-old discrepancy between methods may be explained by a low average C:Si ratio (∼1.4) for the net produced diatom C relative to the net produced bSiO2. We speculate that this low production ratio is not the result of reduced C, but may arise from a significant contribution of non-diatom silicifying organisms to bSiO2 production. The contribution of diatoms to organic matter export was minor (5.7%). These results, and those of the broader project, suggest substantial food-web transformation of diatom organic matter in the euphotic zone, which creates enriched bSiO2 relative to organic matter within the exported material.

  5. Functionally gradient material for membrane reactors to convert methane gas into value-added products

    DOEpatents

    Balachandran, U.; Dusek, J.T.; Kleefisch, M.S.; Kobylinski, T.P.

    1996-11-12

    A functionally gradient material for a membrane reactor for converting methane gas into value-added-products includes an outer tube of perovskite, which contacts air; an inner tube which contacts methane gas, of zirconium oxide, and a bonding layer between the perovskite and zirconium oxide layers. The bonding layer has one or more layers of a mixture of perovskite and zirconium oxide, with the layers transitioning from an excess of perovskite to an excess of zirconium oxide. The transition layers match thermal expansion coefficients and other physical properties between the two different materials. 7 figs.

  6. Functionally gradient material for membrane reactors to convert methane gas into value-added products

    DOEpatents

    Balachandran, Uthamalingam; Dusek, Joseph T.; Kleefisch, Mark S.; Kobylinski, Thadeus P.

    1996-01-01

    A functionally gradient material for a membrane reactor for converting methane gas into value-added-products includes an outer tube of perovskite, which contacts air; an inner tube which contacts methane gas, of zirconium oxide, and a bonding layer between the perovskite and zirconium oxide layers. The bonding layer has one or more layers of a mixture of perovskite and zirconium oxide, with the layers transitioning from an excess of perovskite to an excess of zirconium oxide. The transition layers match thermal expansion coefficients and other physical properties between the two different materials.

  7. Methane production and small intestinal bacterial overgrowth in children living in a slum

    PubMed Central

    Mello, Carolina Santos; Tahan, Soraia; Melli, Lígia Cristina FL; Rodrigues, Mirian Silva do Carmo; de Mello, Ricardo Martin Pereira; Scaletsky, Isabel Cristina Affonso; de Morais, Mauro Batista

    2012-01-01

    AIM: To analyze small intestinal bacterial overgrowth in school-aged children and the relationship between hydrogen and methane production in breath tests. METHODS: This transversal study included 85 children residing in a slum and 43 children from a private school, all aged between 6 and 10 years, in Osasco, Brazil. For characterization of the groups, data regarding the socioeconomic status and basic housing sanitary conditions were collected. Anthropometric data was obtained in children from both groups. All children completed the hydrogen (H2) and methane (CH4) breath test in order to assess small intestinal bacterial overgrowth (SIBO). SIBO was diagnosed when there was an increase in H2 ≥ 20 ppm or CH4 ≥ 10 ppm with regard to the fasting value until 60 min after lactulose ingestion. RESULTS: Children from the slum group had worse living conditions and lower nutritional indices than children from the private school. SIBO was found in 30.9% (26/84) of the children from the slum group and in 2.4% (1/41) from the private school group (P = 0.0007). Greater hydrogen production in the small intestine was observed in children from the slum group when compared to children from the private school (P = 0.007). A higher concentration of hydrogen in the small intestine (P < 0.001) and in the colon (P < 0.001) was observed among the children from the slum group with SIBO when compared to children from the slum group without SIBO. Methane production was observed in 63.1% (53/84) of the children from the slum group and in 19.5% (8/41) of the children from the private school group (P < 0.0001). Methane production was observed in 38/58 (65.5%) of the children without SIBO and in 15/26 (57.7%) of the children with SIBO from the slum. Colonic production of hydrogen was lower in methane-producing children (P = 0.017). CONCLUSION: Children who live in inadequate environmental conditions are at risk of bacterial overgrowth and methane production. Hydrogen is a substrate for

  8. Innovation in biological production and upgrading of methane and hydrogen for use as gaseous transport biofuel.

    PubMed

    Xia, Ao; Cheng, Jun; Murphy, Jerry D

    2016-01-01

    Biofuels derived from biomass will play a major role in future renewable energy supplies in transport. Gaseous biofuels have superior energy balances, offer greater greenhouse gas emission reductions and produce lower pollutant emissions than liquid biofuels. Biogas derived through fermentation of wet organic substrates will play a major role in future transport systems. Biogas (which is composed of approximately 60% methane/hydrogen and 40% carbon dioxide) requires an upgrading process to reduce the carbon dioxide content to less than 3% before it is used as compressed gas in transport. This paper reviews recent developments in fermentative biogas production and upgrading as a transport fuel. Third generation gaseous biofuels may be generated using marine-based algae via two-stage fermentation, cogenerating hydrogen and methane. Alternative biological upgrading techniques, such as biological methanation and microalgal biogas upgrading, have the potential to simultaneously upgrade biogas, increase gaseous biofuel yield and reduce carbon dioxide emission.

  9. Two-phase anaerobic digestion for production of hydrogen-methane mixtures.

    PubMed

    Cooney, Michael; Maynard, Nathan; Cannizzaro, Christopher; Benemann, John

    2007-10-01

    An anaerobic digestion process to produce hydrogen and methane in two sequential stages was investigated, using two bioreactors of 2 and 15 L working volume, respectively. This relative volume ratio (and shorter retention time in the second, CH(4)-producing reactor) was selected, in part, to test the assumption that separation of phase can enhance metabolism in the second methane producing reactor. The reactor system was seeded with conventional anaerobic digester sludge, fed with a glucose-yeast extract--peptone medium and operated under conditions of relatively low mixing, to simulate full scale operation. A total of nine steady states were investigated, spanning a range of feed concentrations, dilution rates, feed carbon to nitrogen ratios and degree of integration of the two stages. The performance of this two-stage process and potential practical applications for the production of clean-burning hydrogen-methane mixtures are discussed.

  10. WASTEWATER reclamation and methane production using water hyacinth and anaerobic digestion

    SciTech Connect

    Chynoweth, D.P.; DoLenc, D.A.; Reddy, K.R.; Schwegler, B.

    1983-06-01

    This paper describes the results of research in progress to evaluate the technical and economic feasibility of utilizing water hyacinth ponds for treatment of domestic wastewater and the utilization of anaerobic digestion for conversion of the hyacinth crop and primary sludge to methane. The system concept illustrated in Figure I employs water hyacinth ponds for secondary and tertiary treatment of effluent from primary treatment (which removes settleable solids). Primary effluent supernatant is passed through water hyacinth ponds which effect organic and nutrient reduction. Collected primary sludge and harvested hyacinth are added as a blend to the anaerobic digestion process where a portion of the organic matter is converted to methane and carbon dioxide. The methane is separated from the carbon dioxide and used as an energy product.

  11. Stimulation of methane generation from nonproductive coal by addition of nutrients or a microbial consortium.

    PubMed

    Jones, Elizabeth J P; Voytek, Mary A; Corum, Margo D; Orem, William H

    2010-11-01

    Biogenic formation of methane from coal is of great interest as an underexploited source of clean energy. The goal of some coal bed producers is to extend coal bed methane productivity and to utilize hydrocarbon wastes such as coal slurry to generate new methane. However, the process and factors controlling the process, and thus ways to stimulate it, are poorly understood. Subbituminous coal from a nonproductive well in south Texas was stimulated to produce methane in microcosms when the native population was supplemented with nutrients (biostimulation) or when nutrients and a consortium of bacteria and methanogens enriched from wetland sediment were added (bioaugmentation). The native population enriched by nutrient addition included Pseudomonas spp., Veillonellaceae, and Methanosarcina barkeri. The bioaugmented microcosm generated methane more rapidly and to a higher concentration than the biostimulated microcosm. Dissolved organics, including long-chain fatty acids, single-ring aromatics, and long-chain alkanes accumulated in the first 39 days of the bioaugmented microcosm and were then degraded, accompanied by generation of methane. The bioaugmented microcosm was dominated by Geobacter sp., and most of the methane generation was associated with growth of Methanosaeta concilii. The ability of the bioaugmentation culture to produce methane from coal intermediates was confirmed in incubations of culture with representative organic compounds. This study indicates that methane production could be stimulated at the nonproductive field site and that low microbial biomass may be limiting in situ methane generation. In addition, the microcosm study suggests that the pathway for generating methane from coal involves complex microbial partnerships.

  12. Marine methane paradox explained by bacterial degradation of dissolved organic matter

    NASA Astrophysics Data System (ADS)

    Repeta, Daniel J.; Ferrón, Sara; Sosa, Oscar A.; Johnson, Carl G.; Repeta, Lucas D.; Acker, Marianne; Delong, Edward F.; Karl, David M.

    2016-12-01

    Biogenic methane is widely thought to be a product of archaeal methanogenesis, an anaerobic process that is inhibited or outcompeted by the presence of oxygen and sulfate. Yet a large fraction of marine methane delivered to the atmosphere is produced in high-sulfate, fully oxygenated surface waters that have methane concentrations above atmospheric equilibrium values, an unexplained phenomenon referred to as the marine methane paradox. Here we use nuclear magnetic resonance spectroscopy to show that polysaccharide esters of three phosphonic acids are important constituents of dissolved organic matter in seawater from the North Pacific. In seawater and pure culture incubations, bacterial degradation of these dissolved organic matter phosphonates in the presence of oxygen releases methane, ethylene and propylene gas. Moreover, we found that in mutants of a methane-producing marine bacterium, Pseudomonas stutzeri, disrupted in the C-P lyase phosphonate degradation pathway, methanogenesis was also disabled, indicating that the C-P lyase pathway can catalyse methane production from marine dissolved organic matter. Finally, the carbon stable isotope ratio of methane emitted during our incubations agrees well with anomalous isotopic characteristics of seawater methane. We estimate that daily cycling of only about 0.25% of the organic matter phosphonate inventory would support the entire atmospheric methane flux at our study site. We conclude that aerobic bacterial degradation of phosphonate esters in dissolved organic matter may explain the marine methane paradox.

  13. Stimulation of methane generation from nonproductive coal by addition of nutrients or a microbial consortium

    USGS Publications Warehouse

    Jones, Elizabeth J.P.; Voytek, Mary A.; Corum, Margo D.; Orem, William H.

    2010-01-01

    Biogenic formation of methane from coal is of great interest as an underexploited source of clean energy. The goal of some coal bed producers is to extend coal bed methane productivity and to utilize hydrocarbon wastes such as coal slurry to generate new methane. However, the process and factors controlling the process, and thus ways to stimulate it, are poorly understood. Subbituminous coal from a nonproductive well in south Texas was stimulated to produce methane in microcosms when the native population was supplemented with nutrients (biostimulation) or when nutrients and a consortium of bacteria and methanogens enriched from wetland sediment were added (bioaugmentation). The native population enriched by nutrient addition included Pseudomonas spp., Veillonellaceae, and Methanosarcina barkeri. The bioaugmented microcosm generated methane more rapidly and to a higher concentration than the biostimulated microcosm. Dissolved organics, including long-chain fatty acids, single-ring aromatics, and long-chain alkanes accumulated in the first 39 days of the bioaugmented microcosm and were then degraded, accompanied by generation of methane. The bioaugmented microcosm was dominated by Geobacter sp., and most of the methane generation was associated with growth of Methanosaeta concilii. The ability of the bioaugmentation culture to produce methane from coal intermediates was confirmed in incubations of culture with representative organic compounds. This study indicates that methane production could be stimulated at the nonproductive field site and that low microbial biomass may be limiting in situ methane generation. In addition, the microcosm study suggests that the pathway for generating methane from coal involves complex microbial partnerships.

  14. Measurements of methane emissions at natural gas production sites in the United States

    PubMed Central

    Allen, David T.; Torres, Vincent M.; Thomas, James; Sullivan, David W.; Harrison, Matthew; Hendler, Al; Herndon, Scott C.; Kolb, Charles E.; Fraser, Matthew P.; Hill, A. Daniel; Lamb, Brian K.; Miskimins, Jennifer; Sawyer, Robert F.; Seinfeld, John H.

    2013-01-01

    Engineering estimates of methane emissions from natural gas production have led to varied projections of national emissions. This work reports direct measurements of methane emissions at 190 onshore natural gas sites in the United States (150 production sites, 27 well completion flowbacks, 9 well unloadings, and 4 workovers). For well completion flowbacks, which clear fractured wells of liquid to allow gas production, methane emissions ranged from 0.01 Mg to 17 Mg (mean = 1.7 Mg; 95% confidence bounds of 0.67–3.3 Mg), compared with an average of 81 Mg per event in the 2011 EPA national emission inventory from April 2013. Emission factors for pneumatic pumps and controllers as well as equipment leaks were both comparable to and higher than estimates in the national inventory. Overall, if emission factors from this work for completion flowbacks, equipment leaks, and pneumatic pumps and controllers are assumed to be representative of national populations and are used to estimate national emissions, total annual emissions from these source categories are calculated to be 957 Gg of methane (with sampling and measurement uncertainties estimated at ±200 Gg). The estimate for comparable source categories in the EPA national inventory is ∼1,200 Gg. Additional measurements of unloadings and workovers are needed to produce national emission estimates for these source categories. The 957 Gg in emissions for completion flowbacks, pneumatics, and equipment leaks, coupled with EPA national inventory estimates for other categories, leads to an estimated 2,300 Gg of methane emissions from natural gas production (0.42% of gross gas production). PMID:24043804

  15. Methane and carbon dioxide production from simulated anaerobic degradation of cattle carcasses

    SciTech Connect

    Yuan Qi; Saunders, Samuel E.; Bartelt-Hunt, Shannon L.

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer This study evaluates methane and carbon dioxide production after land burial of cattle carcasses. Black-Right-Pointing-Pointer Disposal of animal mortalities is often overlooked in evaluating the environmental impacts of animal production. Black-Right-Pointing-Pointer we quantify annual emissions from cattle carcass disposal in the United States as 1.6 Tg CO{sub 2} equivalents. - Abstract: Approximately 2.2 million cattle carcasses require disposal annually in the United States. Land burial is a convenient disposal method that has been widely used in animal production for disposal of both daily mortalities as well as during catastrophic mortality events. To date, greenhouse gas production after mortality burial has not been quantified, and this study represents the first attempt to quantify greenhouse gas emissions from land burial of animal carcasses. In this study, anaerobic decomposition of both homogenized and unhomogenized cattle carcass material was investigated using bench-scale reactors. Maximum yields of methane and carbon dioxide were 0.33 and 0.09 m{sup 3}/kg dry material, respectively, a higher methane yield than that previously reported for municipal solid waste. Variability in methane production rates were observed over time and between reactors. Based on our laboratory data, annual methane emissions from burial of cattle mortalities in the United States could total 1.6 Tg CO{sub 2} equivalents. Although this represents less than 1% of total emissions produced by the agricultural sector in 2009, greenhouse gas emissions from animal carcass burial may be significant if disposal of swine and poultry carcasses is also considered.

  16. Effects of rutin and buckwheat seeds on energy metabolism and methane production in dairy cows.

    PubMed

    Stoldt, Ann-Kathrin; Derno, Michael; Das, Gürbüz; Weitzel, Joachim M; Wolffram, Siegfried; Metges, Cornelia C

    2016-03-01

    Flavonoids are secondary plant metabolites with several health promoting effects. As dairy cows often suffer from metabolic imbalance and health problems, interest is growing in health improvements by plant substances such as flavonoids. Our group has recently shown that the flavonoids quercetin and rutin (a glucorhamnoside of quercetin) are bioavailable in cows when given via a duodenal fistula or orally, respectively, affect glucose metabolism, and have beneficial effects on liver health. Furthermore, flavonoids may reduce rumen methane production in vitro through their antibacterial properties. To test the hypothesis that rutin has effects on energy metabolism, methane production, and production performance in dairy cows, we fed rutin trihydrate at a dose of 100mg/kg of body weight to a group of 7 lactating dairy cows for 2 wk in a crossover design. In a second experiment, 2 cows were fed the same ration but were supplemented with buckwheat seeds (Fagopyrum tartaricum), providing rutin at a dose comparable to the first experiment. Two other cows receiving barley supplements were used as controls in a change-over mode. Blood samples were taken weekly and respiration measurements were performed at the end of each treatment. Supplementation of pure rutin, but not of rutin contained in buckwheat seeds, increased the plasma quercetin content. Methane production and milk yield and composition were not affected by rutin treatment in either form. Plasma glucose, β-hydroxybutyrate, and albumin were increased by pure rutin treatment, indicating a possible metabolic effect of rutin on energy metabolism of dairy cows. In addition, we did not show that in vivo ruminal methane production was reduced by rutin. In conclusion, we could not confirm earlier reports on in vitro methane reduction by rutin supplementation in dairy cows in established lactation.

  17. Mitigation of methane production from cattle by feeding cashew nut shell liquid.

    PubMed

    Shinkai, T; Enishi, O; Mitsumori, M; Higuchi, K; Kobayashi, Y; Takenaka, A; Nagashima, K; Mochizuki, M; Kobayashi, Y

    2012-09-01

    The effects of cashew nut shell liquid (CNSL) feeding on methane production and rumen fermentation were investigated by repeatedly using 3 Holstein nonlactating cows with rumen fistulas. The cows were fed a concentrate and hay diet (6:4 ratio) for 4 wk (control period) followed by the same diet with a CNSL-containing pellet for the next 3 wk (CNSL period). Two trials were conducted using CNSL pellets blended with only silica (trial 1) or with several other ingredients (trial 2). Each pellet type was fed to cows to allow CNSL intake at 4 g/100 kg of body weight per day. Methane production was measured in a respiration chamber system, and energy balance, nutrient digestibility, and rumen microbial changes were monitored. Methane production per unit of dry matter intake decreased by 38.3 and 19.3% in CNSL feeding trials 1 and 2, respectively. Energy loss as methane emission decreased from 9.7 to 6.1% (trial 1) and from 8.4 to 7.0% (trial 2) with CNSL feeding, whereas the loss to feces (trial 1) and heat production (trial 2) increased. Retained energy did not differ between the control and CNSL periods. Digestibility of dry matter and gross energy decreased with CNSL feeding in trial 1, but did not differ in trial 2. Feeding CNSL caused a decrease in acetate and total short-chain fatty acid levels and an increase in propionate proportion in both trials. Relative copy number of methyl coenzyme-M reductase subunit A gene and its expression decreased with CNSL feeding. The relative abundance of fibrolytic or formate-producing species such as Ruminococcus flavefaciens, Butyrivibrio fibrisolvens, and Treponema bryantii decreased, but species related to propionate production, including Prevotella ruminicolla, Selenomonas ruminantium, Anaerovibrio lipolytica, and Succinivibrio dextrinosolvens, increased. If used in a suitable formulation, CNSL acts as a potent methane-inhibiting and propionate-enhancing agent through the alteration of rumen microbiota without adversely

  18. Measurements of methane emissions at natural gas production sites in the United States.

    PubMed

    Allen, David T; Torres, Vincent M; Thomas, James; Sullivan, David W; Harrison, Matthew; Hendler, Al; Herndon, Scott C; Kolb, Charles E; Fraser, Matthew P; Hill, A Daniel; Lamb, Brian K; Miskimins, Jennifer; Sawyer, Robert F; Seinfeld, John H

    2013-10-29

    Engineering estimates of methane emissions from natural gas production have led to varied projections of national emissions. This work reports direct measurements of methane emissions at 190 onshore natural gas sites in the United States (150 production sites, 27 well completion flowbacks, 9 well unloadings, and 4 workovers). For well completion flowbacks, which clear fractured wells of liquid to allow gas production, methane emissions ranged from 0.01 Mg to 17 Mg (mean = 1.7 Mg; 95% confidence bounds of 0.67-3.3 Mg), compared with an average of 81 Mg per event in the 2011 EPA national emission inventory from April 2013. Emission factors for pneumatic pumps and controllers as well as equipment leaks were both comparable to and higher than estimates in the national inventory. Overall, if emission factors from this work for completion flowbacks, equipment leaks, and pneumatic pumps and controllers are assumed to be representative of national populations and are used to estimate national emissions, total annual emissions from these source categories are calculated to be 957 Gg of methane (with sampling and measurement uncertainties estimated at ± 200 Gg). The estimate for comparable source categories in the EPA national inventory is ~1,200 Gg. Additional measurements of unloadings and workovers are needed to produce national emission estimates for these source categories. The 957 Gg in emissions for completion flowbacks, pneumatics, and equipment leaks, coupled with EPA national inventory estimates for other categories, leads to an estimated 2,300 Gg of methane emissions from natural gas production (0.42% of gross gas production).

  19. The Production of Methane, Hydrogen, and Organic Compounds in Ultramafic-Hosted Hydrothermal Vents of the Mid-Atlantic Ridge

    PubMed Central

    Charlou, J.L.; Holm, N.G.; Mousis, O.

    2015-01-01

    Abstract Both hydrogen and methane are consistently discharged in large quantities in hydrothermal fluids issued from ultramafic-hosted hydrothermal fields discovered along the Mid-Atlantic Ridge. Considering the vast number of these fields discovered or inferred, hydrothermal fluxes represent a significant input of H2 and CH4 to the ocean. Although there are lines of evidence of their abiogenic formation from stable C and H isotope results, laboratory experiments, and thermodynamic data, neither their origin nor the reaction pathways generating these gases have been fully constrained yet. Organic compounds detected in the fluids may also be derived from abiotic reactions. Although thermodynamics are favorable and extensive experimental work has been done on Fischer-Tropsch-type reactions, for instance, nothing is clear yet about their origin and formation mechanism from actual data. Since chemolithotrophic microbial communities commonly colonize hydrothermal vents, biogenic and thermogenic processes are likely to contribute to the production of H2, CH4, and other organic compounds. There seems to be a consensus toward a mixed origin (both sources and processes) that is consistent with the ambiguous nature of the isotopic data. But the question that remains is, to what proportions? More systematic experiments as well as integrated geochemical approaches are needed to disentangle hydrothermal geochemistry. This understanding is of prime importance considering the implications of hydrothermal H2, CH4, and organic compounds for the ocean global budget, global cycles, and the origin of life. Key Words: Hydrogen—Methane—Organics—MAR—Abiotic synthesis—Serpentinization—Ultramafic-hosted hydrothermal vents. Astrobiology 15, 381–399. PMID:25984920

  20. Methane production in microbial reverse-electrodialysis methanogenesis cells (MRMCs) using thermolytic solutions.

    PubMed

    Luo, Xi; Zhang, Fang; Liu, Jia; Zhang, Xiaoyuan; Huang, Xia; Logan, Bruce E

    2014-01-01

    The utilization of bioelectrochemical systems for methane production has attracted increasing attention, but producing methane in these systems requires additional voltage to overcome large cathode overpotentials. To eliminate the need for electrical grid energy, we constructed a microbial reverse-electrodialysis methanogenesis cell (MRMC) by placing a reverse electrodialysis (RED) stack between an anode with exoelectrogenic microorganisms and a methanogenic biocathode. In the MRMC, renewable salinity gradient energy was converted to electrical energy, thus providing the added potential needed for methane evolution from the cathode. The feasibility of the MRMC was examined using three different cathode materials (stainless steel mesh coated with platinum, SS/Pt; carbon cloth coated with carbon black, CC/CB; or a plain graphite fiber brush, GFB) and a thermolytic solution (ammonium bicarbonate) in the RED stack. A maximum methane yield of 0.60 ± 0.01 mol-CH4/mol-acetate was obtained using the SS/Pt biocathode, with a Coulombic recovery of 75 ± 2% and energy efficiency of 7.0 ± 0.3%. The CC/CB biocathode MRMC had a lower methane yield of 0.55 ± 0.02 mol-CH4/mol-acetate, which was twice that of the GFB biocathode MRMC. COD removals (89-91%) and Coulombic efficiencies (74-81%) were similar for all cathode materials. Linear sweep voltammetry and electrochemical impedance spectroscopy tests demonstrated that cathodic microorganisms enhanced electron transfer from the cathode compared to abiotic controls. These results show that the MRMC has significant potential for production of nearly pure methane using low-grade waste heat and a source of waste organic matter at the anode.

  1. Evidence for methane-subsidised secondary production in a groundwater-fed lowland river.

    NASA Astrophysics Data System (ADS)

    Trimmer, M.; Grey, J.; Hildrew, A.; Jackson, M.

    2009-04-01

    We are probably familiar with the chemosynthetic ecosystems of the deep Pacific, where life in the dark is coupled to the oxidation of sulphur from ‘black smokers' rather than the sun, but few, if any, would suspect such a mode of life in the classic chalk rivers of southern England. We measured the delta13C values of dominant primary consumers and their potential food sources in a groundwater-fed lowland river. The delta13C of most consumers, such as Gammarus and Simulium, reflected that of the dominant forms of photosynthetic production, whereas the cased larvae of two caddis flies (Agapetus and Silo) were consistently 13C-depleted throughout the year. The river water was supersaturated (50-60 times atmospheric) with methane, reflecting both supersaturation in the groundwater and local production in fine sediments. We measured significant rates of methane oxidation, which generates 13C-depleted organic carbon, in the biofilms on gravel, on the caddis fly cases, and on the bottom of larger rocks. In addition, there was a marked difference in the ratio of methane oxidising potential to chlorophyll a across those substrata. This ratio was below detection in the biofilm (i.e. no methane oxidation) on the tops of rocks, greater on the bottom of rocks, and maximal for the gravels and the caddis cases. If the caddis larvae acquire most of their carbon by grazing the tops of such rocks (where they are normally found), then they must acquire their depleted delta13C values by occasionally grazing biofilm where the ratio of methane oxidation to chlorophyll was much greater, and the most likely candidate is from their own cases. Grazing methane oxidising bacteria could provide the caddis larvae with up to 30 % of their carbon, which could represent a true subsidy from an ancient groundwater source.

  2. High rate production of hydrogen/methane from various substrates and wastes.

    PubMed

    Nishio, Naomichi; Nakashimada, Yutaka

    2004-01-01

    To treat soluble and solid wastes and recover energy from them, high rate methane fermentation, especially using the UASB (upflow anaerobic sludge blanket) reactor, and hydrogen fermentation using various microorganisms and microbial consortia have been investigated intensively in Japan. In this chapter, recent works on high rate methane fermentation in Japan are reviewed, focusing on: 1) basic studies into the applicability of the UASB reactor for various substrates such as propionate, lactate, ethanol, glucose and phenol; 2) its applications to unfeasible conditions, such as lipid and protein containing wastes, low temperature and high salt-containing wastes; 3) progress made in the field of advanced UASB reactors, and; 4) research into methane fermentation from solid wastes, such as from cellulosic materials, municipal sewage sludge, and mud sediments. Following this, although hydrogen fermentation with photosynthetic microorganisms or anaerobic bacteria was researched, for this review we have focused on fermentative hydrogen production using strictly or facultative anaerobes and microbial consortia in Japan, since high rate production of hydrogen-methane via a two-stage process was judged to be more attractive for biological hydrogen production and wastewater treatments.

  3. Waste lipids to energy: how to optimize methane production from long‐chain fatty acids (LCFA)

    PubMed Central

    Alves, M. Madalena; Pereira, M. Alcina; Sousa, Diana Z.; Cavaleiro, Ana J.; Picavet, Merijn; Smidt, Hauke; Stams, Alfons J. M.

    2009-01-01

    Summary The position of high‐rate anaerobic technology (HR‐AnWT) in the wastewater treatment and bioenergy market can be enhanced if the range of suitable substrates is expanded. Analyzing existing technologies, applications and problems, it is clear that, until now, wastewaters with high lipids content are not effectively treated by HR‐AnWT. Nevertheless, waste lipids are ideal potential substrates for biogas production, since theoretically more methane can be produced, when compared with proteins or carbohydrates. In this minireview, the classical problems of lipids methanization in anaerobic processes are discussed and new concepts to enhance lipids degradation are presented. Reactors operation, feeding strategies and prospects of technological developments for wastewater treatment are discussed. Long‐chain fatty acids (LCFA) degradation is accomplished by syntrophic communities of anaerobic bacteria and methanogenic archaea. For optimal performance these syntrophic communities need to be clustered in compact aggregates, which is often difficult to achieve with wastewaters that contain fats and lipids. Driving the methane production from lipids/LCFA at industrial scale without risk of overloading and inhibition is still a challenge that has the potential for filling a gap in the existing processes and technologies for biological methane production associated to waste and wastewater treatment. PMID:21255287

  4. Methane production enhancement by an independent cathode in integrated anaerobic reactor with microbial electrolysis.

    PubMed

    Cai, Weiwei; Han, Tingting; Guo, Zechong; Varrone, Cristiano; Wang, Aijie; Liu, Wenzong

    2016-05-01

    Anaerobic digestion (AD) represents a potential way to achieve energy recovery from waste organics. In this study, a novel bioelectrochemically-assisted anaerobic reactor is assembled by two AD systems separated by anion exchange membrane, with the cathode placing in the inside cylinder (cathodic AD) and the anode on the outside cylinder (anodic AD). In cathodic AD, average methane production rate goes up to 0.070 mL CH4/mL reactor/day, which is 2.59 times higher than AD control reactor (0.027 m(3) CH4/m(3)/d). And COD removal is increased ∼15% over AD control. When changing to sludge fermentation liquid, methane production rate has been further increased to 0.247 mL CH4/mL reactor/day (increased by 51.53% comparing with AD control). Energy recovery efficiency presents profitable gains, and economic revenue from increased methane totally self-cover the cost of input electricity. The study indicates that cathodic AD could cost-effectively enhance methane production rate and degradation of glucose and fermentative liquid.

  5. Methane Production and Methanogenic Archaea in the Digestive Tracts of Millipedes (Diplopoda)

    PubMed Central

    Šustr, Vladimír; Chroňáková, Alica; Semanová, Stanislava; Tajovský, Karel; Šimek, Miloslav

    2014-01-01

    Methane production by intestinal methanogenic Archaea and their community structure were compared among phylogenetic lineages of millipedes. Tropical and temperate millipedes of 35 species and 17 families were investigated. Species that emitted methane were mostly in the juliform orders Julida, Spirobolida, and Spirostreptida. The irregular phylogenetic distribution of methane production correlated with the presence of the methanogen-specific mcrA gene. The study brings the first detailed survey of methanogens’ diversity in the digestive tract of millipedes. Sequences related to Methanosarcinales, Methanobacteriales, Methanomicrobiales and some unclassified Archaea were detected using molecular profiling (DGGE). The differences in substrate preferences of the main lineages of methanogenic Archaea found in different millipede orders indicate that the composition of methanogen communities may reflect the differences in available substrates for methanogenesis or the presence of symbiotic protozoa in the digestive tract. We conclude that differences in methane production in the millipede gut reflect differences in the activity and proliferation of intestinal methanogens rather than an absolute inability of some millipede taxa to host methanogens. This inference was supported by the general presence of methanogenic activity in millipede faecal pellets and the presence of the 16S rRNA gene of methanogens in all tested taxa in the two main groups of millipedes, the Helminthophora and the Pentazonia. PMID:25028969

  6. Waste lipids to energy: how to optimize methane production from long-chain fatty acids (LCFA).

    PubMed

    Alves, M Madalena; Pereira, M Alcina; Sousa, Diana Z; Cavaleiro, Ana J; Picavet, Merijn; Smidt, Hauke; Stams, Alfons J M

    2009-09-01

    The position of high-rate anaerobic technology (HR-AnWT) in the wastewater treatment and bioenergy market can be enhanced if the range of suitable substrates is expanded. Analyzing existing technologies, applications and problems, it is clear that, until now, wastewaters with high lipids content are not effectively treated by HR-AnWT. Nevertheless, waste lipids are ideal potential substrates for biogas production, since theoretically more methane can be produced, when compared with proteins or carbohydrates. In this minireview, the classical problems of lipids methanization in anaerobic processes are discussed and new concepts to enhance lipids degradation are presented. Reactors operation, feeding strategies and prospects of technological developments for wastewater treatment are discussed. Long-chain fatty acids (LCFA) degradation is accomplished by syntrophic communities of anaerobic bacteria and methanogenic archaea. For optimal performance these syntrophic communities need to be clustered in compact aggregates, which is often difficult to achieve with wastewaters that contain fats and lipids. Driving the methane production from lipids/LCFA at industrial scale without risk of overloading and inhibition is still a challenge that has the potential for filling a gap in the existing processes and technologies for biological methane production associated to waste and wastewater treatment.

  7. Organosulfates and oxidation products from biogenic hydrocarbons in fine aerosols from a forest in North West Europe during spring

    NASA Astrophysics Data System (ADS)

    Kristensen, Kasper; Glasius, Marianne

    2011-09-01

    Organosulfates of monoterpenes and isoprene, as well as their oxidation products have been identified in biogenic secondary organic aerosols (BSOA) from both laboratory and field studies. Organosulfates provide an interesting coupling between air pollution and formation of low-volatility BSOA. HPLC quadrupole time-of-flight mass spectrometry was used to study polar acidic monoterpene and isoprene oxidation products including pinic acid, pinonic and terpenylic acid along with organosulfates and nitrooxy organosulfates in aerosols from ambient air. The method was first validated by analysis of spiked quartz filters, which showed acceptable recoveries >74% for pinic acid, pinonic acid, camphor sulphonic acid and adipic acid. Acetonitrile was identified as a better solvent than methanol for extraction and analysis of pinonic acid and adipic acid, due to improved analytical sensitivity and prevention of methyl ester formation during sample extraction. PM 1 (i.e, aerosols with an aerodynamic diameter ≤1 μm) were collected during spring 2008 in a forest in Denmark with mixed deciduous and coniferous trees. Average concentrations of the most abundant compounds were: pinic acid: 1.5 ng m -3, pinonic acid: 3.0 ng m -3, terpenylic acid: 0.8 ng m -3 and 3-methyl-1,2,3-butanetricarboxylic acid: 3.0 ng m -3. Organosulfates and nitrooxy organosulfates were identified in a majority of the daily samples and the highest levels were observed during a warm period in late spring. As a first approach, due to the lack of authentic standards, organosulfates and nitrooxy organosulfates were tentatively quantified based on the analytical response of camphor sulphonic acid. Generally the concentrations of organosulfates and nitrooxy organosulfates were lower than first generation oxidation products. The maximum concentration of a total of 10 organosulfates and nitrooxy organosulfates were found to be about three times lower than pinonic acid with a maximum concentration of 8 ng m -3. A

  8. Assessment of methane emissions from oil and gas production pads using mobile measurements.

    PubMed

    Brantley, Halley L; Thoma, Eben D; Squier, William C; Guven, Birnur B; Lyon, David

    2014-12-16

    A new mobile methane emissions inspection approach, Other Test Method (OTM) 33A, was used to quantify short-term emission rates from 210 oil and gas production pads during eight two-week field studies in Texas, Colorado, and Wyoming from 2010 to 2013. Emission rates were log-normally distributed with geometric means and 95% confidence intervals (CIs) of 0.33 (0.23, 0.48), 0.14 (0.11, 0.19), and 0.59 (0.47, 0.74) g/s in the Barnett, Denver-Julesburg, and Pinedale basins, respectively. This study focused on sites with emission rates above 0.01 g/s and included short-term (i.e., condensate tank flashing) and maintenance-related emissions. The results fell within the upper ranges of the distributions observed in recent onsite direct measurement studies. Considering data across all basins, a multivariate linear regression was used to assess the relationship of methane emissions to well age, gas production, and hydrocarbon liquids (oil or condensate) production. Methane emissions were positively correlated with gas production, but only approximately 10% of the variation in emission rates was explained by variation in production levels. The weak correlation between emission and production rates may indicate that maintenance-related stochastic variables and design of production and control equipment are factors determining emissions.

  9. Effects of heavy metals on methane production in tropical rice soils.

    PubMed

    Mishra, S R; Bharati, K; Sethunathan, N; Adhya, T K

    1999-09-01

    In a laboratory incubation study, the effect of select heavy metals on methane (CH(4)) production in three rice soils was investigated under flooded conditions. Heavy metals behaved differently in their effect on methanogenesis in different soils and methane-producing bacteria. Cd, Cu, and Pb inhibited CH(4) production in all the soils. Zn stimulated CH(4) production in the alluvial soil, but inhibited it in laterite and acid sulfate soils. Cr effectively inhibited CH(4) production in the alluvial soil, but stimulated it in laterite and acid sulfate soils. The stimulatory effect of Zn and the inhibitory effect of Cr on methanogenesis in alluvial soil were attributed to their stimulation or inhibition of methanogenic bacterial population.

  10. Potential methane production and oxidation in soil reclamation covers of an oil sands mining site in Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Pum, Lisa; Reichenauer, Thomas; Germida, Jim

    2015-04-01

    Anthropogenic activities create a number of significant greenhouse gases and thus potentially contribute to global warming. Methane production is significant in some agricultural production systems and from wetlands. In soil, methane can be oxidised by methanotrophic bacteria. However, little is known about methane production and oxidation in oil sand reclamation covers. The purpose of this study was to investigate methane production and oxidation potential of tailing sands and six different reclamation layers of oil sands mining sites in Alberta, Canada. Methane production and oxidation potential were investigated in laboratory scale microcosms through continuous headspace analysis using gas chromatography. Samples from a reclamation layer were collected at the Canadian Natural Resources Limited (CNRL) reclamation site at depths of 0-10 cm, 10-20 cm and 20-40 cm in October 2014. In addition, tailing sands provided by Suncor Energy Inc. and soil from a CNRL wetland were studied for methane production. Samples were dried, crushed and sieved to 4 mm, packed into serum bottle microcosms and monitored for eight weeks. Methane production potential was assessed by providing an anoxic environment and by adjusting the samples to a moisture holding capacity of 100 %. Methane oxidation potential was examined by an initial application of 2 vol % methane to the microcosms and by adjusting the samples to a moisture holding capacity of 50 %. Microcosm headspace gas was analysed for methane, carbon dioxide, nitrous oxide and oxygen. All experiments were carried out in triplicates, including controls. SF6 and Helium were used as internal standards to detect potential leaks. Our results show differences for methane production potential between the soil depths, tailing sands and wetlands. Moreover, there were differences in the methane oxidation potential of substrate from the three depths investigated and between the reclamation layers. In conclusion, the present study shows that

  11. Enhancing the use of methane as a feedstock for the biological production of chemicals. Annual report, January-December 1989

    SciTech Connect

    Srivastava, V.J.; Kelley, R.L.; Conrad, J.R.; Hoefer, D.E.; Glover, B.

    1993-12-01

    The objective of the work is to determine the technical and economic feasibility of the microbial utilization of methane for biocatalytic co-oxidation processes. Identifying the specific chemicals that (1) have a significant market potential, (2) could be produced cost effectively from methane either as a synthesis product or as a co-oxidation product by methane-utilizing microorganisms, and (3) could be recovered in a relatively high concentration by a non-energy-intensive product-separation technique is the primary goal of the program. In the annual report, several physiological parameters such as temperature, pH, and micronutrients have been evaluated for the enhancement of propylene oxide production.

  12. Exploration strategies based on a coalbed methane producibility model

    SciTech Connect

    Scott, A.R.; Kaiser, W.R.; Hamilton, D.S.; Tyler, R.; Finley, R.J.

    1996-12-31

    Knowing geologic and hydrologic characteristics of a basin does not necessarily lead to a determination of its coalbed methane producibility because it is the synergy among key hydrogeologic controls that governs producibility. Detailed studies performed in the San Juan, Piceance, and Sand Wash Basins determined that the key hydrogeologic factors affecting producibility include depositional setting and coal distribution, tectonic and structural setting, coal rank and gas generation, hydrodynamics, permeability, and gas content. The conceptual model based on these factors provides a rationale for exploration and development strategies for unexplored areas or in basins having established or limited production. Exceptionally high productivity requires good permeability; thick, laterally continuous high-rank and high-gas-content coals; dynamic flow of ground water through those coals; generation of secondary biogenic gases; and migration and conventional trapping of thermogenic and biogenic gases. Higher coalbed methane producibility commonly occurs in areas of upward flow associated with permeability barriers (no-flow boundaries). Fluid migration across a large gathering area orthogonal to permeability barriers and/or in situ generation of secondary biogenic gases concentrate the coal gas, resulting in higher gas contents. Low coalbed methane production is typically associated with very low permeability systems; the absence of conventional or hydrodynamic traps; and thin, low-rank coals below the threshold of thermogenic gas generation. Production from relatively low-gas-content coals in highly permeable recharge areas may result in excessive water and limited coalbed methane production. Thus, high permeability can be as detrimental to coalbed methane producibility as is low permeability.

  13. Exploration strategies based on a coalbed methane producibility model

    SciTech Connect

    Scott, A.R.; Kaiser, W.R.; Hamilton, D.S.; Tyler, R.; Finley, R.J. )

    1996-01-01

    Knowing geologic and hydrologic characteristics of a basin does not necessarily lead to a determination of its coalbed methane producibility because it is the synergy among key hydrogeologic controls that governs producibility. Detailed studies performed in the San Juan, Piceance, and Sand Wash Basins determined that the key hydrogeologic factors affecting producibility include depositional setting and coal distribution, tectonic and structural setting, coal rank and gas generation, hydrodynamics, permeability, and gas content. The conceptual model based on these factors provides a rationale for exploration and development strategies for unexplored areas or in basins having established or limited production. Exceptionally high productivity requires good permeability; thick, laterally continuous high-rank and high-gas-content coals; dynamic flow of ground water through those coals; generation of secondary biogenic gases; and migration and conventional trapping of thermogenic and biogenic gases. Higher coalbed methane producibility commonly occurs in areas of upward flow associated with permeability barriers (no-flow boundaries). Fluid migration across a large gathering area orthogonal to permeability barriers and/or in situ generation of secondary biogenic gases concentrate the coal gas, resulting in higher gas contents. Low coalbed methane production is typically associated with very low permeability systems; the absence of conventional or hydrodynamic traps; and thin, low-rank coals below the threshold of thermogenic gas generation. Production from relatively low-gas-content coals in highly permeable recharge areas may result in excessive water and limited coalbed methane production. Thus, high permeability can be as detrimental to coalbed methane producibility as is low permeability.

  14. Enhancement of bioenergy production from organic wastes by two-stage anaerobic hydrogen and methane production process.

    PubMed

    Luo, Gang; Xie, Li; Zhou, Qi; Angelidaki, Irini

    2011-09-01

    The present study investigated a two-stage anaerobic hydrogen and methane process for increasing bioenergy production from organic wastes. A two-stage process with hydraulic retention time (HRT) 3d for hydrogen reactor and 12d for methane reactor, obtained 11% higher energy compared to a single-stage methanogenic process (HRT 15 d) under organic loading rate (OLR) 3 gVS/(L d). The two-stage process was still stable when the OLR was increased to 4.5 gVS/(Ld), while the single-stage process failed. The study further revealed that by changing the HRT(hydrogen):HRT(methane) ratio of the two-stage process from 3:12 to 1:14, 6.7%, more energy could be obtained. Microbial community analysis indicated that the dominant bacterial species were different in the hydrogen reactors (Thermoanaerobacterium thermosaccharolyticum-like species) and methane reactors (Clostridium thermocellum-like species). The changes of substrates and HRT did not change the dominant species. The archaeal community structures in methane reactors were similar both in single- and two- stage reactors, with acetoclastic methanogens Methanosarcina acetivorans-like organisms as the dominant species.

  15. Fungal secondary metabolites from Monascus spp. reduce rumen methane production in vitro and in vivo.

    PubMed

    Morgavi, D P; Martin, C; Boudra, H

    2013-02-01

    Decreasing methanogenesis without affecting fermentation and digestion of feeds in the rumen can reduce the environmental impact of ruminant production and have a beneficial effect on feed conversion efficiency. In this work, metabolites produced by Monascus spp. molds were assayed for their antimethanogenic activity in vitro and in vivo. The capacity of 7 strains of Monascus to produce secondary metabolites was assessed in solid media. Monitored metabolites included the statins monacolin K, pravastatin, and mevastatin, and the mycotoxin citrinin. Ethanolic extracts from 5 different solid media from 2 selected strains were tested in vitro. Fermentation was not negatively affected by any treatment, but one extract decreased methane production (P < 0.05). This extract was further assayed in 3 consecutive batch incubations where a marked decrease in methane was observed in the third batch (P < 0.05). In contrast, methane produced in flasks with pure monacolin K was not different from controls (P > 0.05). Rice on which the selected Monascus sp. was grown also decreased methane production when used as substrate for in vitro incubations (P < 0.05). The effect of Monascus-fermented rice on methane production was then assayed in vivo. Six wethers were adapted to a diet containing rice grain and hay (1:1 ratio). Rice was then replaced by fermented rice and given to animals for nearly 2 wk. Animals were monitored for a further 2 wk after the treatment. Daily methane emissions decreased (P < 0.05) by 30% after 2 to 3 d into the treatment and remained low throughout the administration period. This change was associated with reduced ruminal acetate to propionate ratio and decreased numbers of methanogens as detected by quantitative PCR (P < 0.05). In contrast, no changes in the methanogenic community were observed by denaturing gradient gel electrophoresis (DGGE). Total bacteria numbers increased (P < 0.05) with changes in the DGGE profile community, whereas protozoa were not

  16. Effect of biochar addition on hydrogen and methane production in two-phase anaerobic digestion of aqueous carbohydrates food waste.

    PubMed

    Sunyoto, Nimas M S; Zhu, Mingming; Zhang, Zhezi; Zhang, Dongke

    2016-11-01

    Effect of biochar addition on hydrogen and methane production in two-phase anaerobic digestion of aqueous carbohydrates was studied using bench-scale bioreactors. The cultures with biochar additions were placed in 100ml reactors and incubated at 35°C and pH 5 for hydrogen production. The residual cultures were then used for methane production, incubated at 35°C and pH 7. Daily yields of hydrogen and methane and weekly yield of volatile fatty acids (VFA) were measured. The hydrogen and methane production potentials, rate and lag phases of the two phases were analysed using the Gompertz model. The results showed that biochar addition increased the maximum production rates of hydrogen by 32.5% and methane 41.6%, improved hydrogen yield by 31.0% and methane 10.0%, and shortened the lag phases in the two phases by 36.0% and 41.0%, respectively. Biochar addition also enhanced VFA generation during hydrogen production and VFA degradation in methane production.

  17. Methane-rich syngas production from hydrocarbon fuels using multi-functional catalyst/capture agent

    DOEpatents

    Siefert, Nicholas S.; Shekhawat, Dushyant; Berry, David A.; Surdoval, Wayne A.

    2017-02-07

    The disclosure provides a gasification process for the production of a methane-rich syngas at temperatures exceeding 400.degree. C. through the use of an alkali hydroxide MOH, using a gasification mixture comprised of at least 0.25 moles and less than 2 moles of water for each mole of carbon, and at least 0.15 moles and less than 2 moles of alkali hydroxide MOH for each mole of carbon. These relative amounts allow the production of a methane-rich syngas at temperatures exceeding 400.degree. C. by enabling a series of reactions which generate H.sub.2 and CH.sub.4, and mitigate the reforming of methane. The process provides a methane-rich syngas comprised of roughly 20% (dry molar percentage) CH.sub.4 at temperatures above 400.degree. C., and may effectively operate within an IGFC cycle at reactor temperatures between 400-900.degree. C. and pressures in excess of 10 atmospheres.

  18. Rerouting Cellular Electron Flux To Increase the Rate of Biological Methane Production

    PubMed Central

    Catlett, Jennie L.; Ortiz, Alicia M.

    2015-01-01

    Methanogens are anaerobic archaea that grow by producing methane, a gas that is both an efficient renewable fuel and a potent greenhouse gas. We observed that overexpression of the cytoplasmic heterodisulfide reductase enzyme HdrABC increased the rate of methane production from methanol by 30% without affecting the growth rate relative to the parent strain. Hdr enzymes are essential in all known methane-producing archaea. They function as the terminal oxidases in the methanogen electron transport system by reducing the coenzyme M (2-mercaptoethane sulfonate) and coenzyme B (7-mercaptoheptanoylthreonine sulfonate) heterodisulfide, CoM-S-S-CoB, to regenerate the thiol-coenzymes for reuse. In Methanosarcina acetivorans, HdrABC expression caused an increased rate of methanogenesis and a decrease in metabolic efficiency on methylotrophic substrates. When acetate was the sole carbon and energy source, neither deletion nor overexpression of HdrABC had an effect on growth or methane production rates. These results suggest that in cells grown on methylated substrates, the cell compensates for energy losses due to expression of HdrABC with an increased rate of substrate turnover and that HdrABC lacks the appropriate electron donor in acetate-grown cells. PMID:26162885

  19. Rerouting Cellular Electron Flux To Increase the Rate of Biological Methane Production.

    PubMed

    Catlett, Jennie L; Ortiz, Alicia M; Buan, Nicole R

    2015-10-01

    Methanogens are anaerobic archaea that grow by producing methane, a gas that is both an efficient renewable fuel and a potent greenhouse gas. We observed that overexpression of the cytoplasmic heterodisulfide reductase enzyme HdrABC increased the rate of methane production from methanol by 30% without affecting the growth rate relative to the parent strain. Hdr enzymes are essential in all known methane-producing archaea. They function as the terminal oxidases in the methanogen electron transport system by reducing the coenzyme M (2-mercaptoethane sulfonate) and coenzyme B (7-mercaptoheptanoylthreonine sulfonate) heterodisulfide, CoM-S-S-CoB, to regenerate the thiol-coenzymes for reuse. In Methanosarcina acetivorans, HdrABC expression caused an increased rate of methanogenesis and a decrease in metabolic efficiency on methylotrophic substrates. When acetate was the sole carbon and energy source, neither deletion nor overexpression of HdrABC had an effect on growth or methane production rates. These results suggest that in cells grown on methylated substrates, the cell compensates for energy losses due to expression of HdrABC with an increased rate of substrate turnover and that HdrABC lacks the appropriate electron donor in acetate-grown cells.

  20. Hydrogen and methane production through two-stage mesophilic anaerobic digestion of olive pulp.

    PubMed

    Koutrouli, Eleni C; Kalfas, Haralabos; Gavala, Hariklia N; Skiadas, Ioannis V; Stamatelatou, Katerina; Lyberatos, Gerasimos

    2009-08-01

    The present study focused on the anaerobic biohydrogen production from olive pulp (two phase olive mill wastes, TPOMW) and the subsequent anaerobic treatment of the effluent for methane production under mesophilic conditions in a two-stage process. Biohydrogen production from water-diluted (1:4) olive pulp was investigated at hydraulic retention times (HRT) of 30 h, 14.5 h and 7.5 h while methane production from the effluent of hydrogenogenic reactor was studied at 20 d, 15 d, 10d and 5d HRT. In comparison with previous studies, it has been shown that the thermophilic hydrogen production process was more efficient than the mesophilic one in both hydrogen production rate and yield. The methanogenic reactor was successfully operated at 20, 15 and 10 days HRT while it failed when an HRT of 5 days was applied. Methane productivity reached the maximum value of 1.13+/-0.08 L/L/d at 10 days HRT whereas the methane yield increased with the HRT. The Anaerobic Digestion Model no. 1 (ADM1) was applied to the obtained experimental data from the methanogenic reactor to simulate the digester response at all HRT tested. The ability of the model to predict the experimental results was evident even in the case of the process failure, thus implying that the ADM1 could be a valuable tool for process design even in the case of a complex feedstock. In general, the two-stage anaerobic digestion proved to be a stable, reliable and effective process for energy recovery and stabilization treatment of olive pulp.

  1. Geomechanical Behavior of Hydrate-Bearing Sediments in the Ulleung Basin during Methane Production

    NASA Astrophysics Data System (ADS)

    Cho, G. C.; Kim, A. R.; KIM, S. J.

    2014-12-01

    The potential of methane hydrate deposits in the Ulleung Basin of the Korean East Sea was suggested by the Korea Institute of Geoscience and Mineral Resources between 2000 and 2004. In a few years, a pilot production project is planned as the world's second offshore methane production project. The basin has a water depth of 1500-2300 m; however, the depth of the hydrate occurrence zone is relatively shallow (about 100-200 mbsf) for gas hydrate production. There is high potential for geomechanical stability problems such as seafloor subsidence, differential settlement, effective stress concentrations, marine landslides, and wellbore instability. In this study, 2D axisymmetric numerical modeling is conducted to simulate the depressurization process in the Ulleung Basin for methane gas production. The coupled mechanical-flow-thermal model used for this purpose incorporates the physical processes of hydrate dissociation, the pore fluid flow, thermal advection, and the geomechanical response of hydrate-bearing sediments. Using the coupled model, two high-potential sites are compared with respect to the pore pressure, temperature change, production efficiency, and geomechanical stability. During depressurization, deformation of the sediments around the production well occurs due to the pore pressure difference and the increase in the effective stress in the depressurized region. This tendency becomes more pronounced due to the decrease in the stiffness of the hydrate-bearing sediments, which is caused by hydrate dissociation. In addition, the latent heat induced by methane hydrate dissociation and thermal advection due to the pore fluid flow have greater effects on the dissociation range and pace than do the geomechanical behaviors. Meanwhile, higher production efficiency, a larger latent heat effect and less settlement are induced in the site, which consists of thick sand layers with greater stiffness and permeability levels than mud layers.

  2. Conversion of crude oil to methane by a microbial consortium enriched from oil reservoir production waters

    PubMed Central

    Berdugo-Clavijo, Carolina; Gieg, Lisa M.

    2014-01-01

    The methanogenic biodegradation of crude oil is an important process occurring in petroleum reservoirs and other oil-containing environments such as contaminated aquifers. In this process, syntrophic bacteria degrade hydrocarbon substrates to products such as acetate, and/or H2 and CO2 that are then used by methanogens to produce methane in a thermodynamically dependent manner. We enriched a methanogenic crude oil-degrading consortium from production waters sampled from a low temperature heavy oil reservoir. Alkylsuccinates indicative of fumarate addition to C5 and C6 n-alkanes were identified in the culture (above levels found in controls), corresponding to the detection of an alkyl succinate synthase encoding gene (assA/masA) in the culture. In addition, the enrichment culture was tested for its ability to produce methane from residual oil in a sandstone-packed column system simulating a mature field. Methane production rates of up to 5.8 μmol CH4/g of oil/day were measured in the column system. Amounts of produced methane were in relatively good agreement with hydrocarbon loss showing depletion of more than 50% of saturate and aromatic hydrocarbons. Microbial community analysis revealed that the enrichment culture was dominated by members of the genus Smithella, Methanosaeta, and Methanoculleus. However, a shift in microbial community occurred following incubation of the enrichment in the sandstone columns. Here, Methanobacterium sp. were most abundant, as were bacterial members of the genus Pseudomonas and other known biofilm forming organisms. Our findings show that microorganisms enriched from petroleum reservoir waters can bioconvert crude oil components to methane both planktonically and in sandstone-packed columns as test systems. Further, the results suggest that different organisms may contribute to oil biodegradation within different phases (e.g., planktonic vs. sessile) within a subsurface crude oil reservoir. PMID:24829563

  3. Conversion of crude oil to methane by a microbial consortium enriched from oil reservoir production waters.

    PubMed

    Berdugo-Clavijo, Carolina; Gieg, Lisa M

    2014-01-01

    The methanogenic biodegradation of crude oil is an important process occurring in petroleum reservoirs and other oil-containing environments such as contaminated aquifers. In this process, syntrophic bacteria degrade hydrocarbon substrates to products such as acetate, and/or H2 and CO2 that are then used by methanogens to produce methane in a thermodynamically dependent manner. We enriched a methanogenic crude oil-degrading consortium from production waters sampled from a low temperature heavy oil reservoir. Alkylsuccinates indicative of fumarate addition to C5 and C6 n-alkanes were identified in the culture (above levels found in controls), corresponding to the detection of an alkyl succinate synthase encoding gene (assA/masA) in the culture. In addition, the enrichment culture was tested for its ability to produce methane from residual oil in a sandstone-packed column system simulating a mature field. Methane production rates of up to 5.8 μmol CH4/g of oil/day were measured in the column system. Amounts of produced methane were in relatively good agreement with hydrocarbon loss showing depletion of more than 50% of saturate and aromatic hydrocarbons. Microbial community analysis revealed that the enrichment culture was dominated by members of the genus Smithella, Methanosaeta, and Methanoculleus. However, a shift in microbial community occurred following incubation of the enrichment in the sandstone columns. Here, Methanobacterium sp. were most abundant, as were bacterial members of the genus Pseudomonas and other known biofilm forming organisms. Our findings show that microorganisms enriched from petroleum reservoir waters can bioconvert crude oil components to methane both planktonically and in sandstone-packed columns as test systems. Further, the results suggest that different organisms may contribute to oil biodegradation within different phases (e.g., planktonic vs. sessile) within a subsurface crude oil reservoir.

  4. Study on methane fermentation and production of vitamin B12 from alcohol waste slurry.

    PubMed

    Zhang, Zhenya; Quan, Taisheng; Li, Pomin; Zhang, Yansheng; Sugiura, Norio; Maekawa, Takaaki

    2004-01-01

    We studied biogas fermentation from alcohol waste fluid to evaluate the anaerobic digestion process and the production of vitamin B12 as a byproduct. Anaerobic digestion using acclimated methanogens was performed using the continuously stirred tank reactor (CSTR) and fixed-bed reactor packed with rock wool as carrier material at 55 degrees C. We also studied the effects of metal ions added to the culture broth on methane and vitamin B12 formation. Vitamin B12 production was 2.92 mg/L in the broth of the fixed-bed reactor, twice that of the CSTR. The optimum concentrations of trace metal ions added to the culture liquid for methane and vitamin B12 production were 1.0 and 8 mL/L for the CSTR and fixed-bed reactor, respectively. Furthermore, an effective method for extracting and purifying vitamin B12 from digested fluid was developed.

  5. Effect of urea addition on giant reed ensilage and subsequent methane production by anaerobic digestion.

    PubMed

    Liu, Shan; Ge, Xumeng; Liew, Lo Niee; Liu, Zhe; Li, Yebo

    2015-09-01

    The effect of urea addition on giant reed ensilage and sequential anaerobic digestion (AD) of the ensiled giant reed was evaluated. The dry matter loss during ensilage (up to 90 days) with or without urea addition was about 1%. Addition of 2% urea enhanced production of lactic acid by about 4 times, and reduced production of propionic acid by 2-8 times. Besides, urea addition reduced degradation of cellulose and hemicellulose, and increased degradation of lignin in giant reed during ensilage. Ensilage with or without urea addition had no significant effects on the enzymatic digestibility of giant reed, but ensilage with urea addition achieved a cumulative methane yield of 173 L/kg VS, which was 18% higher than that of fresh giant reed. The improved methane yield of giant reed could be attributed to the production of organic acids and ethanol during ensilage.

  6. Primary production control of methane emission from wetlands

    NASA Technical Reports Server (NTRS)

    Whiting, G. J.; Chanton, J. P.

    1993-01-01

    Based on simultaneous measurements of CO2 and CH4 exchange in wetlands extending from subarctic peatlands to subtropical marshes, a positive correlation between CH4 emission and net ecosystem production is reported. It is suggested that net ecosystem production is a master variable integrating many factors which control CH4 emission in vegetated wetlands. It is found that about 3 percent of the daily net ecosystem production is emitted back to the atmosphere as CH4. With projected stimulation of primary production and soil microbial activity in wetlands associated with elevated atmospheric CO2 concentration, the potential for increasing CH4 emission from inundated wetlands, further enhancing the greenhouse effect, is examined.

  7. The distribution of methane in groundwater in Alberta (Canada) and associated aqueous geochemistry conditions

    NASA Astrophysics Data System (ADS)

    Humez, Pauline; Mayer, Bernhard; Nightingale, Michael; Becker, Veith; Kingston, Andrew; Taylor, Stephen; Millot, Romain; Kloppmann, Wolfram

    2016-04-01

    Development of unconventional energy resources such as shale gas and coalbed methane has generated some public concern with regard to the protection of groundwater and surface water resources from leakage of stray gas from the deep subsurface. In terms of environmental impact to and risk assessment of shallow groundwater resources, the ultimate challenge is to distinguish: (a) natural in-situ production of biogenic methane, (b) biogenic or thermogenic methane migration into shallow aquifers due to natural causes, and (c) thermogenic methane migration from deep sources due to human activities associated with the exploitation of conventional or unconventional oil and gas resources. We have conducted a NSERC-ANR co-funded baseline study investigating the occurrence of methane in shallow groundwater of Alberta (Canada), a province with a long record of conventional and unconventional hydrocarbon exploration. Our objective was to assess the occurrence and sources of methane in shallow groundwaters and to also characterize the hydrochemical environment in which the methane was formed or transformed through redox processes. Ultimately our aim was to determine whether methane was formed in-situ or whether it migrated from deeper formations into shallow aquifers. Combining hydrochemical and dissolved and free geochemical gas data from 372 groundwater samples obtained from 186 monitoring wells of the provincial groundwater observation well network (GOWN) in Alberta, it was found that methane is ubiquitous in groundwater in Alberta and is predominantly of biogenic origin. The highest concentrations of dissolved biogenic methane (> 0.01 mM or > 0.2 mg/L), characterized by δ13CCH4 values < -55‰, occurred in anoxic Na-Cl, Na-HCO3 and Na-HCO3-Cl type groundwater with negligible concentrations of nitrate and sulfate suggesting that methane was formed in-situ under methanogenic conditions consistent with the redox ladder concept. Despite quite variable gas concentrations and a

  8. Hydropower's Biogenic Carbon Footprint.

    PubMed

    Scherer, Laura; Pfister, Stephan

    2016-01-01

    Global warming is accelerating and the world urgently needs a shift to clean and renewable energy. Hydropower is currently the largest renewable source of electricity, but its contribution to climate change mitigation is not yet fully understood. Hydroelectric reservoirs are a source of biogenic greenhouse gases and in individual cases can reach the same emission rates as thermal power plants. Little is known about the severity of their emissions at the global scale. Here we show that the carbon footprint of hydropower is far higher than previously assumed, with a global average of 173 kg CO2 and 2.95 kg CH4 emitted per MWh of electricity produced. This results in a combined average carbon footprint of 273 kg CO2e/MWh when using the global warming potential over a time horizon of 100 years (GWP100). Nonetheless, this is still below that of fossil energy sources without the use of carbon capture and sequestration technologies. We identified the dams most promising for capturing methane for use as alternative energy source. The spread among the ~1500 hydropower plants analysed in this study is large and highlights the importance of case-by-case examinations.

  9. Hydropower's Biogenic Carbon Footprint

    PubMed Central

    Pfister, Stephan

    2016-01-01

    Global warming is accelerating and the world urgently needs a shift to clean and renewable energy. Hydropower is currently the largest renewable source of electricity, but its contribution to climate change mitigation is not yet fully understood. Hydroelectric reservoirs are a source of biogenic greenhouse gases and in individual cases can reach the same emission rates as thermal power plants. Little is known about the severity of their emissions at the global scale. Here we show that the carbon footprint of hydropower is far higher than previously assumed, with a global average of 173 kg CO2 and 2.95 kg CH4 emitted per MWh of electricity produced. This results in a combined average carbon footprint of 273 kg CO2e/MWh when using the global warming potential over a time horizon of 100 years (GWP100). Nonetheless, this is still below that of fossil energy sources without the use of carbon capture and sequestration technologies. We identified the dams most promising for capturing methane for use as alternative energy source. The spread among the ~1500 hydropower plants analysed in this study is large and highlights the importance of case-by-case examinations. PMID:27626943

  10. Laboratory-scale bioaugmentation relieves acetate accumulation and stimulates methane production in stalled anaerobic digesters.

    PubMed

    Town, Jennifer R; Dumonceaux, Tim J

    2016-01-01

    An imbalance between acidogenic and methanogenic organisms during anaerobic digestion can result in increased accumulation of volatile fatty acids, decreased reactor pH, and inhibition of methane-producing Archaea. Most commonly the result of organic input overload or poor inoculum selection, these microbiological and biochemical changes severely hamper reactor performance, and there are a few tools available to facilitate reactor recovery. A small, stable consortium capable of catabolizing acetate and producing methane was propagated in vitro and evaluated as a potential bioaugmentation tool for stimulating methanogenesis in acidified reactors. Replicate laboratory-scale batch digesters were seeded with a combination of bioethanol stillage waste and a dairy manure inoculum previously observed to result in high volatile fatty acid accumulation and reactor failure. Experimental reactors were then amended with the acetoclastic consortium, and control reactors were amended with sterile culture media. Within 7 days, bioaugmented reactors had significantly reduced acetate accumulation and the proportion of methane in the biogas increased from 0.2 ± 0 to 74.4 ± 9.9 % while control reactors showed no significant reduction in acetate accumulation or increase in methane production. Organisms from the consortium were enumerated using specific quantitative PCR assays to evaluate their growth in the experimental reactors. While the abundance of hydrogenotrophic microorganisms remained stable during the recovery period, an acetoclastic methanogen phylogenetically similar to Methanosarcina sp. increased more than 100-fold and is hypothesized to be the primary contributor to reactor recovery. Genomic sequencing of this organism revealed genes related to the production of methane from acetate, hydrogen, and methanol.

  11. [Influence of substrate COD on methane production in single-chambered microbial electrolysis cell].

    PubMed

    Teng, Wen-Kai; Liu, Guang-Li; Luo, Hai-Ping; Zhang, Ren-Duo; Fu, Shi-Yu

    2015-03-01

    The chemical oxygen demand (COD) of substrate can affect the microbial activity of both anode and cathode biofilm in the single-chamber methanogenic microbial electrolysis cell (MEC). In order to investigate the effect of COD on the performance of MEC, a single chamber MEC was constructed with biocathode. With the change of initial concentration of COD (700, 1 000 and 1 350 mg x L(-1)), the methane production rate, COD removal and energy efficiency in the MEC were examined under different applied voltages. The results showed that the methane production rate and COD removal increased with the increasing COD. With the applied voltage changing from 0.3 to 0.7 V, the methane production rate increased at the COD of 700 mg x L(-1), while it increased at first and then decreased at the COD of 1000 mg x L(-1) and 1350 mg x L(-1). A similar trend was observed for the COD removal. The cathode potential reached the minimum (- 0.694 ± 0.001) V as the applied voltage was 0.5 V, which therefore facilitated the growth of methanogenic bacteria and improved the methane production rate and energy efficiency of the MEC. The maximum energy income was 0.44 kJ ± 0.09 kJ (1450 kJ x m(-3)) in the MEC, which was obtained at the initial COD of 1000 mg x L(-1) and the applied voltage of 0.5 V. Methanogenic MECs could be used for the treatment of wastewaters containing low organic concentrations to achieve positive energy production, which might provide a new method to recover energy from low-strength domestic wastewater.

  12. Redox controls on methane formation, migration and fate in shallow aquifers

    NASA Astrophysics Data System (ADS)

    Humez, Pauline; Mayer, Bernhard; Nightingale, Michael; Becker, Veith; Kingston, Andrew; Taylor, Stephen; Bayegnak, Guy; Millot, Romain; Kloppmann, Wolfram

    2016-07-01

    Development of unconventional energy resources such as shale gas and coalbed methane has generated some public concern with regard to the protection of groundwater and surface water resources from leakage of stray gas from the deep subsurface. In terms of environmental impact to and risk assessment of shallow groundwater resources, the ultimate challenge is to distinguish (a) natural in situ production of biogenic methane, (b) biogenic or thermogenic methane migration into shallow aquifers due to natural causes, and (c) thermogenic methane migration from deep sources due to human activities associated with the exploitation of conventional or unconventional oil and gas resources. This study combines aqueous and gas (dissolved and free) geochemical and isotope data from 372 groundwater samples obtained from 186 monitoring wells of the provincial Groundwater Observation Well Network (GOWN) in Alberta (Canada), a province with a long record of conventional and unconventional hydrocarbon exploration. We investigated whether methane occurring in shallow groundwater formed in situ, or whether it migrated into the shallow aquifers from elsewhere in the stratigraphic column. It was found that methane is ubiquitous in groundwater in Alberta and is predominantly of biogenic origin. The highest concentrations of biogenic methane (> 0.01 mM or > 0.2 mgL-1), characterized by δ13CCH4 values < -55 ‰, occurred in anoxic Na-Cl, Na-HCO3, and Na-HCO3-Cl type groundwaters with negligible concentrations of nitrate and sulfate suggesting that methane was formed in situ under methanogenic conditions for 39.1 % of the samples. In only a few cases (3.7 %) was methane of biogenic origin found in more oxidizing shallow aquifer portions suggesting limited upward migration from deeper methanogenic aquifers. Of the samples, 14.1 % contained methane with δ13CCH4 values > -54 ‰, potentially suggesting a thermogenic origin, but aqueous and isotope

  13. Anaerobic digestion of grape pomace: Biochemical characterization of the fractions and methane production in batch and continuous digesters.

    PubMed

    El Achkar, Jean H; Lendormi, Thomas; Hobaika, Zeina; Salameh, Dominique; Louka, Nicolas; Maroun, Richard G; Lanoisellé, Jean-Louis

    2016-04-01

    In this study, we have estimated the biogas and methane production from grape pomace (variety Cabernet Franc). The physical and chemical characteristics of the raw material were determined, and the structural polysaccharides were identified and analyzed by the Van Soest method. Batch anaerobic digestions were carried out to assess the methane production of the grape pomace, pulp and seeds. The obtained cumulative methane productions are 0.125, 0.165 and 0.052 Nm(3) kg COD(-1) for grape pomace, pulps and seeds, respectively. The effect of grinding on the methane potential of the substrates, as a mechanical pretreatment, was evaluated. We found that it increased the anaerobic biodegradability for grape pomace, pulp and seeds by 13.1%, 4.8% and 22.2%, respectively. On the other hand, the methane potential of the grape pomace was determined in a laboratory pilot plant (12L) continuously mixed with an organic loading rate of 2.5 kg COD m(3) d(-1) and a hydraulic retention time of 30 days. The corresponding biogas production was 6.43 × 10(-3) Nm(3) d(-1), with a methane content of 62.3%. Thus, the pilot plant's efficiency compared to that achieved in the batch process was 81.2%. Finally, a significant correlation was found between the biochemical content and methane production.

  14. Effect of combined herbal feed additives on methane, total gas production and rumen fermentation

    PubMed Central

    Chaturvedi, Indu; Dutta, Tapas Kumar; Singh, Pawan Kumar; Sharma, Ashwani

    2015-01-01

    The present study was to evaluate effect of herbal feed additives on methane and total gas production during the rumen fermentation for environment and animal health concern. Different parts of the five medicinal plants were selected such as leaf and small stems of Ocimum sanctum (Tulsi), roots of Curcuma longa (Haldi), fruits of Emblica officinalis (Amla), leaves of Azadirachta indica (Neem) and leaves and small stem of Clerodendrum phlomidis (Arni) for our study. Addition of different herbal additive combinations did not influence IVDMD and total gas production however methane production (mg/g of substrate DM) was significantly (P<0.05) reduced in Amla: Neem and Neem: Arni combinations. Total nitrogen significantly (P<0.01) increased in the combinations of Tulsi: Haldi and Amla: Neem. TCA–ppt-N is significantly (P<0.01) increased in Tulsi: Haldi, Haldi: Amla, Amla: Neem and Neem: Arni however NH3-N (mg/dl) significantly decreased in all treatments. We conclude that the screening of plant combinations, Amla: Neem and Neem: Arni have potential to decrease methane production and our herbal feed supplements have no side-effects on the ruminant in small amount. PMID:26124571

  15. Optimization of thermal-dilute sulfuric acid pretreatment for enhancement of methane production from cassava residues.

    PubMed

    Zhang, Qinghua; Tang, Lei; Zhang, Jianhua; Mao, Zhonggui; Jiang, Li

    2011-02-01

    In this study, the pretreatment of cassava residues by thermal-dilute sulfuric acid (TDSA) hydrolysis was investigated by means of a statistically designed set of experiments. A three-factor central composite design (CCD) was employed to identify the optimum pretreatment condition of cassava residues for methane production. The individual and interactive effects of temperature, H(2)SO(4) concentration and reaction time on increase of methane yield (IMY) were evaluated by applying response surface methodology (RSM). After optimization, the resulting optimum pretreatment condition was 157.84°C, utilizing 2.99% (w/w TS) H(2)SO(4) for 20.15 min, where the maximum methane yield (248 mL/g VS) was 56.96% higher than the control (158 mL/g VS), which was very close to the predict value 56.53%. These results indicate the model obtained through RSM analysis is suit to predict the optimum pretreatment condition and there is great potential of using TDSA pretreatment of cassava residues to enhance methane yield.

  16. Methane production from formate, acetate and H2/CO2; focusing on kinetics and microbial characterization.

    PubMed

    Pan, Xiaofang; Angelidaki, Irini; Alvarado-Morales, Merlin; Liu, Houguang; Liu, Yuhong; Huang, Xu; Zhu, Gefu

    2016-10-01

    For evaluating the methanogenesis from typical methanogenic precursors (formate, acetate and H2/CO2), CH4 production kinetics were investigated at 37±1°C in batch anaerobic digestion tests and stimulated by modified Gompertz model. The results showed that maximum methanation rate from formate, acetate and H2/CO2 were 19.58±0.49, 42.65±1.17 and 314.64±3.58NmL/gVS/d in digested manure system and 6.53±0.31, 132.04±3.96 and 640.16±19.92NmL/gVS/d in sewage sludge system during second generation incubation. Meanwhile the model could not fit well in granular sludge system, while the rate of formate methanation was faster than from H2/CO2 and acetate. Considering both the kinetic results and microbial assay we could conclude that H2/CO2 methanation was the fastest methanogenic step in digested manure and sewage sludge system with Methanomicrobiales as dominant methanogens, while granular sludge with Methanobacteriales as dominant methanogens contributed to the fastest formate methanation.

  17. Bioconversion of industrial hemp to ethanol and methane: the benefits of steam pretreatment and co-production.

    PubMed

    Kreuger, Emma; Sipos, Bálint; Zacchi, Guido; Svensson, Sven-Erik; Björnsson, Lovisa

    2011-02-01

    Several scenarios for ethanol production, methane production (by anaerobic digestion) and co-production of these, using autumn harvested hemp as substrate, were investigated and compared in terms of gross energy output. Steam pretreatment improved the methane production rate compared with mechanical grinding. The methane yield of steam pretreated stems was similar both with and without pre-hydrolysis with cellulolytic enzymes. Co-production of ethanol and methane from steam pretreated stems gave a high yield of transportation fuel, 11.1-11.7 MJ/kg processed stem dry matter (DM); more than twice that of ethanol production alone from hexoses, 4.4-5.1 MJ/kg processed stem DM. Co-production from the whole hemp plant would give 2600-3000 L ethanol and 2800-2900 m(3) methane, in total 171-180 GJ per 10,000 m(2) of agricultural land, based on a biomass yield of 16 Mg DM. Of this, the yeast and enzymes from ethanol production were estimated to contribute 700 m(3) (27 GJ) of methane.

  18. An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production

    PubMed Central

    Hristov, Alexander N.; Oh, Joonpyo; Giallongo, Fabio; Frederick, Tyler W.; Harper, Michael T.; Weeks, Holley L.; Branco, Antonio F.; Moate, Peter J.; Deighton, Matthew H.; Williams, S. Richard O.; Kindermann, Maik; Duval, Stephane

    2015-01-01

    A quarter of all anthropogenic methane emissions in the United States are from enteric fermentation, primarily from ruminant livestock. This study was undertaken to test the effect of a methane inhibitor, 3-nitrooxypropanol (3NOP), on enteric methane emission in lactating Holstein cows. An experiment was conducted using 48 cows in a randomized block design with a 2-wk covariate period and a 12-wk data collection period. Feed intake, milk production, and fiber digestibility were not affected by the inhibitor. Milk protein and lactose yields were increased by 3NOP. Rumen methane emission was linearly decreased by 3NOP, averaging about 30% lower than the control. Methane emission per unit of feed dry matter intake or per unit of energy-corrected milk were also about 30% less for the 3NOP-treated cows. On average, the body weight gain of 3NOP-treated cows was 80% greater than control cows during the 12-wk experiment. The experiment demonstrated that the methane inhibitor 3NOP, applied at 40 to 80 mg/kg feed dry matter, decreased methane emissions from high-producing dairy cows by 30% and increased body weight gain without negatively affecting feed intake or milk production and composition. The inhibitory effect persisted over 12 wk of treatment, thus offering an effective methane mitigation practice for the livestock industries. PMID:26229078

  19. An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production.

    PubMed

    Hristov, Alexander N; Oh, Joonpyo; Giallongo, Fabio; Frederick, Tyler W; Harper, Michael T; Weeks, Holley L; Branco, Antonio F; Moate, Peter J; Deighton, Matthew H; Williams, S Richard O; Kindermann, Maik; Duval, Stephane

    2015-08-25

    A quarter of all anthropogenic methane emissions in the United States are from enteric fermentation, primarily from ruminant livestock. This study was undertaken to test the effect of a methane inhibitor, 3-nitrooxypropanol (3NOP), on enteric methane emission in lactating Holstein cows. An experiment was conducted using 48 cows in a randomized block design with a 2-wk covariate period and a 12-wk data collection period. Feed intake, milk production, and fiber digestibility were not affected by the inhibitor. Milk protein and lactose yields were increased by 3NOP. Rumen methane emission was linearly decreased by 3NOP, averaging about 30% lower than the control. Methane emission per unit of feed dry matter intake or per unit of energy-corrected milk were also about 30% less for the 3NOP-treated cows. On average, the body weight gain of 3NOP-treated cows was 80% greater than control cows during the 12-wk experiment. The experiment demonstrated that the methane inhibitor 3NOP, applied at 40 to 80 mg/kg feed dry matter, decreased methane emissions from high-producing dairy cows by 30% and increased body weight gain without negatively affecting feed intake or milk production and composition. The inhibitory effect persisted over 12 wk of treatment, thus offering an effective methane mitigation practice for the livestock industries.

  20. Methane production from the red seaweed gracilaria tikvahiae

    SciTech Connect

    Hanisak, M.D.

    1981-01-01

    Stable continuous anaerobic digestion of the title seaweed was maintained in large (120 L) digesters for more than 20 months, with an average gas (60% CH4) production of 0.4 L/g volatile solids. The average bioconversion efficiency was approximately 48%. When the retention time, t, was increased (i.e., loading rate decreased) from 10 to 60 days the total production of biogas and CH4 (as well as the percent CH4 and the reduction of total volatile solids) increased to maximum at t = 30 days and decreased at t = 60 days. Biogas and CH4 production on the basis of volatile solids added increased to less than or equal to 60 days, as did the percent volatile solids reduction. The pH in the digesters increased with increasing t.

  1. Methanation of CO and CO/sub 2/ for heat production

    SciTech Connect

    Arcilla, N.T.; Plumlee, D.E.

    1981-01-01

    This study explores workable CO and CO/sub 2/ methanation systems for process heat as part of a Thermo-Chemical Heat Pipe (TCHP) based on methane reforming. Tested methanator designs and methanation catalyst materials were reviewed to identify those suitable in high temperature, high pressure methanation. 7 refs.

  2. Methane production by anaerobic digestion of water hyacinth (Eichhornia crassipes)

    SciTech Connect

    Klass, D.L.; Ghosh, S.

    1980-01-01

    Water hyacinth under conventional high-rate digestion conditions exhibited higher CH4 yields and energy recovery efficiencies when grown in sewage-fed lagoons than when grown in a fresh water pond. Mesophilic digestion provided the highest recovery of feed energy in the product gas as CH4, while thermophilic digestion, when operated at sufficiently high loading rates and reduced detention times, gave the highest specific CH4 production rates. CH4 yields, volatile solids reduction, and energy recovery as CH4 from the sewage-grown water hyacinth were in the same range as those observed for other biomass substrates when digested under similar conditions.

  3. Production and dispersion of dissolved methane in southeastern Bering Sea. Final report

    SciTech Connect

    Cline, J.D.; Kelly-Hansen, K.; Katz, C.N.

    1982-01-01

    The purpose of the study was to use dissolved methane as a tracer of mean circulation and to define vertical and horizontal mixing scales in local regions of the southeastern Bering Sea. The subregions selected for study included St. George Basin, a fault basin located on the outer shelf of Bristol Bay, and the North Aleutian Shelf. Both regions were identified as potential off-shore leasing sites for gas and oil production.

  4. Temperature response of methane oxidation and production potentials in peatland ecosystems across Finland

    NASA Astrophysics Data System (ADS)

    Welti, Nina; Korrensalo, Aino; Kerttula, Johanna; Maljanen, Marja; Uljas, Salli; Lohila, Annalea; Laine, Anna; Vesala, Timo; Elliott, David; Tuittila, Eeva-Stiina

    2016-04-01

    It has been suggested that the ecosystems located in the high latitudes are especially sensitive to warming. Therefore, we compared 14 peatland systems throughout Finland along a latitudinal gradient from 69°N to 61°N to examine the response of methane production and methane oxidation with warming climate. Peat samples were taken at the height of the growing season in 2015 from 0 - 10cm below the water table depth. The plant communities in sampling locations were described by estimating cover of each plant species and pH of water was measured. Upon return to the lab, we made two parallel treatments, under anoxic and oxic conditions in order to calculate the CH4 production and consumption potentials of the peat and used three temperatures, 4°C, 17.5°C, and 30°C to examine the temperature effect on the potentials. We hypothesized that there will be an observable response curve in CH4 production and oxidation relative to temperature with a greater response with increasing latitude. In general, increasing temperature increased the potential for CH4 production and oxidation, at some sites, the potential was highest at 17.5°C, indicating that there is an optimum temperature threshold for the in situ methane producing and oxidizing microbial communities. Above this threshold, the peat microbial communities are not able to cope with increasing temperature. This is especially noticeable for methane oxidation at sites above 62°N. As countries are being expected to adequately account for their greenhouse gas budgets with increasing temperature models, knowing where the temperature threshold exists is of critical importance.

  5. Effect of nickel ions on anaerobic methane production from water hyacinth.

    PubMed

    Cai, Xuan; Hong, Zi-Jian; Dai, Rui-Hua; Liu, Yan; Liu, Xiang

    2012-01-01

    The effect of different concentrations of nickel ions (Ni(2+), 0, 10, 40 and 80 mg/L) on the anaerobic methane production of water hyacinth were investigated. Under these four concentrations, the methane production in 40 d was 2,275, 2,703, 3,210 and 2,481 mL, respectively. This situation illustrated that the Ni(2+) promoted the growth of hydrogen-producing acetic acid bacteria and methanogenic bacteria, even at high concentrations (i.e. 40-80 mg/L). The highest methane production per unit weight water hyacinth reached 206 mL/gTS with 40 mg/L Ni(2+). Meanwhile, the modified Gompertz and Logistic equations were applied to describe the effect on anaerobic culture of Ni(2+). According to these models, the values of methane production potential (mL) for four concentrations were in the following order: 40 mg/L (3,123.42 ± 60.08) > 10 mg/L (2,541.16 ± 46.94) > 80 mg/L (2,432.36 ± 40.18) > 0 mg/L (2,238.10 ± 31.90). According to the analysis of the digestate, the residual concentration of Ni(2+) was approximately 1.05-4.9 mg/L, which was relatively low compared with the Ni(2+) concentrations in the raw feedstock. The results would provide academic guidance and technical support for treatment of water hyacinth with an accumulation of heavy metals.

  6. Anthropogenic Sulfur Perturbations on Biogenic Oxidation: SO2 Additions Impact Gas-Phase OH Oxidation Products of α- and β-Pinene.

    PubMed

    Friedman, Beth; Brophy, Patrick; Brune, William H; Farmer, Delphine K

    2016-02-02

    In order to probe how anthropogenic pollutants can impact the atmospheric oxidation of biogenic emissions, we investigated how sulfur dioxide (SO2) perturbations impact the oxidation of two monoterpenes, α-and β-pinene. We used chemical ionization mass spectrometry to examine changes in both individual molecules and gas-phase bulk properties of oxidation products as a function of SO2 addition. SO2 perturbations impacted the oxidation systems of α-and β-pinene, leading to an ensemble of products with a lesser degree of oxygenation than unperturbed systems. These changes may be due to shifts in the OH:HO2 ratio from SO2 oxidation and/or to SO3 reacting directly with organic molecules. Van Krevelen diagrams suggest a shift from gas-phase functionalization by alcohol/peroxide groups to functionalization by carboxylic acid or carbonyl groups, consistent with a decreased OH:HO2 ratio. Increasing relative humidity dampens the impact of the perturbation. This decrease in oxygenation may impact secondary organic aerosol formation in regions dominated by biogenic emissions with nearby SO2 sources. We observed sulfur-containing organic compounds following SO2 perturbations of monoterpene oxidation; whether these are the result of photochemistry or an instrumental artifact from ion-molecule clustering remains uncertain. However, our results demonstrate that the two monoterpene isomers produce unique suites of oxidation products.

  7. Dimers and organosulfates derived from biogenic oxidation products in aerosols during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) in California 2007 and 2009 (Invited)

    NASA Astrophysics Data System (ADS)

    Glasius, M.; Worton, D. R.; Kristensen, K.; Nguyen, Q.; Surratt, J.; Enggrob, K. L.; Bouvier-Brown, N. C.; Farmer, D.; Docherty, K. S.; Platt, S.; Bilde, M.; Nøjgaard, J. K.; Seinfeld, J.; Jimenez, J. L.; Goldstein, A.

    2010-12-01

    Oxidation products of biogenic volatile organic compounds, such as monoterpenes and isoprene, contribute to biogenic secondary organic aerosol (BSOA). The organosulfate derivatives of these compounds are formed through heterogeneous reactions involving sulphur compounds, with a considerable contribution from anthropogenic sources. Organosulfate derivatives of biogenic oxidation products thus belong to a new group of anthropogenic enhanced biogenic SOA (ABSOA). The Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) during summers of 2007 and 2009 provided an excellent platform at Blodgett Forest, California (a ponderosa pine plantation) for studying ABSOA. Typically, polluted air masses were transported upslope from the California Central Valley during day, while night conditions were influenced by downslope transport of air masses, low local atmospheric mixing and formation of a shallow boundary layer. We collected particle samples (PM2.5) as one nighttime and two daytime samples per day. After extraction of filters in polar organic solvents (i.e. acetonitrile or methanol), organic aerosol constituents were analyzed by HPLC coupled through an electrospray inlet to a quadrupole time-of-flight mass spectrometer (qTOF-MS). Organosulfates and nitrooxy organosulfates derived from oxidation products of α-pinene, β-pinene, limonene and isoprene were identified based on their molecular mass and MS fragmentation patterns. Measurements by High Resolution Time of Flight Aerosol Mass Spectrometry (HR-ToF-AMS) show high mass loadings of nitrate in the night and morning samples with highest levels of the nitrooxy organosulfates with MW 295 and MW 297. This may indicate that elevated levels of nitrate and nitrooxy organosulfates are formed in the same polluted air mass, probably through nitrate radical reactions. Terpenylic acid, diterpenylic acid acetate, and methylbutane tricarboxylic acid were found at concentrations comparable to pinic acid. A dimer of

  8. MATHEMATICAL MODEL FOR METHANE PRODUCTION FROM LANDFILL BIOREACTOR - A DISCUSSION PAPER HTTP://OIPS.AIP.ORG/EEO/

    EPA Science Inventory

    This discussion explains the experimental results of a landfill bioreactor (LFBR) from a microbiological perspective and provides a feasible strategy to evaluate methane production performance, since suitable models are complicated and not sufficiently reliable for anaerobic-syst...

  9. Magnetite nanoparticles facilitate methane production from ethanol via acting as electron acceptors.

    PubMed

    Yang, Zhiman; Shi, Xiaoshuang; Wang, Chuanshui; Wang, Lin; Guo, Rongbo

    2015-11-12

    Potential for interspecies hydrogen transfer within paddy soil enrichments obtained via addition of magnetite nanoparticles and ethanol (named as PEM) was investigated. To do this, PEM derived from rice field of Hangzhou (named as PEM-HZ) was employed, because it offered the best methane production performance. Methane production and Fe (III) reduction proceeded in parallel in the presence of magnetite. Inhibition experiments with 2-bromoethane sulfonate (BES) or phosphate showed that interspecies hydrogen transfer and Fe (III) reduction also occurred in methane production from ethanol. 16S rRNA-based Illumina sequencing results showed that Dechloromonas, Thauera, Desulfovibrio and Clostridium were the dominant putative Fe (III) -reducers, and that hydrogenotrophic Methanobacterium accounted for about 88% of the total archaeal community. These results indicated that magnetite nanoparticles that acted as electron acceptor could facilitate rapid oxidation of ethanol by members of the Fe (III) -reducers in PEM-HZ and establishment of the syntrophic relationship of Fe (III) -reducers with Methanobacterium via interspecies hydrogen transfer. Our results could offer a model to understand the microbial interaction with magnetite from a novel angle during methanogenesis.

  10. Magnetite nanoparticles facilitate methane production from ethanol via acting as electron acceptors

    PubMed Central

    Yang, Zhiman; Shi, Xiaoshuang; Wang, Chuanshui; Wang, Lin; Guo, Rongbo

    2015-01-01

    Potential for interspecies hydrogen transfer within paddy soil enrichments obtained via addition of magnetite nanoparticles and ethanol (named as PEM) was investigated. To do this, PEM derived from rice field of Hangzhou (named as PEM-HZ) was employed, because it offered the best methane production performance. Methane production and Fe (III) reduction proceeded in parallel in the presence of magnetite. Inhibition experiments with 2-bromoethane sulfonate (BES) or phosphate showed that interspecies hydrogen transfer and Fe (III) reduction also occurred in methane production from ethanol. 16S rRNA-based Illumina sequencing results showed that Dechloromonas, Thauera, Desulfovibrio and Clostridium were the dominant putative Fe (III) -reducers, and that hydrogenotrophic Methanobacterium accounted for about 88% of the total archaeal community. These results indicated that magnetite nanoparticles that acted as electron acceptor could facilitate rapid oxidation of ethanol by members of the Fe (III) -reducers in PEM-HZ and establishment of the syntrophic relationship of Fe (III) -reducers with Methanobacterium via interspecies hydrogen transfer. Our results could offer a model to understand the microbial interaction with magnetite from a novel angle during methanogenesis. PMID:26559132

  11. Magnetite nanoparticles facilitate methane production from ethanol via acting as electron acceptors

    NASA Astrophysics Data System (ADS)

    Yang, Zhiman; Shi, Xiaoshuang; Wang, Chuanshui; Wang, Lin; Guo, Rongbo

    2015-11-01

    Potential for interspecies hydrogen transfer within paddy soil enrichments obtained via addition of magnetite nanoparticles and ethanol (named as PEM) was investigated. To do this, PEM derived from rice field of Hangzhou (named as PEM-HZ) was employed, because it offered the best methane production performance. Methane production and Fe (III) reduction proceeded in parallel in the presence of magnetite. Inhibition experiments with 2-bromoethane sulfonate (BES) or phosphate showed that interspecies hydrogen transfer and Fe (III) reduction also occurred in methane production from ethanol. 16S rRNA-based Illumina sequencing results showed that Dechloromonas, Thauera, Desulfovibrio and Clostridium were the dominant putative Fe (III) -reducers, and that hydrogenotrophic Methanobacterium accounted for about 88% of the total archaeal community. These results indicated that magnetite nanoparticles that acted as electron acceptor could facilitate rapid oxidation of ethanol by members of the Fe (III) -reducers in PEM-HZ and establishment of the syntrophic relationship of Fe (III) -reducers with Methanobacterium via interspecies hydrogen transfer. Our results could offer a model to understand the microbial interaction with magnetite from a novel angle during methanogenesis.

  12. Toward a Functional Definition of Methane Super-Emitters: Application to Natural Gas Production Sites.

    PubMed

    Zavala-Araiza, Daniel; Lyon, David; Alvarez, Ramón A; Palacios, Virginia; Harriss, Robert; Lan, Xin; Talbot, Robert; Hamburg, Steven P

    2015-07-07

    Emissions from natural gas production sites are characterized by skewed distributions, where a small percentage of sites-commonly labeled super-emitters-account for a majority of emissions. A better characterization of super-emitters is needed to operationalize ways to identify them and reduce emissions. We designed a conceptual framework that functionally defines superemitting sites as those with the highest proportional loss rates (methane emitted relative to methane produced). Using this concept, we estimated total methane emissions from natural gas production sites in the Barnett Shale; functionally superemitting sites accounted for roughly three-fourths of total emissions. We discuss the potential to reduce emissions from these sites, under the assumption that sites with high proportional loss rates have excess emissions resulting from abnormal or otherwise avoidable operating conditions, such as malfunctioning equipment. Because the population of functionally superemitting sites is not expected to be static over time, continuous monitoring will likely be necessary to identify them and improve their operation. This work suggests that achieving and maintaining uniformly low emissions across the entire population of production sites will require mitigation steps at a large fraction of sites.

  13. Methane production from horse manure and stall waste with softwood bedding.

    PubMed

    Wartell, Brian A; Krumins, Valdis; Alt, Jeffrey; Kang, Kathleen; Schwab, Bryan J; Fennell, Donna E

    2012-05-01

    Substantial stall waste is generated from horses on softwood bedding. The methane potential (G(pot)) of horse manure and constructed mixtures of stall waste with softwood bedding was determined at 35°C. G(pot) of 68, 191 and 273 mL/g volatile solids (VS) were estimated for three separate batches of horse manure, indicating variability in the material. Cumulative energy production over 20-40 days ranged from 3.11 ± 0.92 to 8.45 ± 5.42 × 10(5)kJ/metric ton wet weight horse manure alone, and from 1.69 ± 0.39 to 3.91 ± 0.47 × 10(5)kJ/metric ton wet weight horse manure plus softwood stall bedding (mixed at a 1:1 ratio on a VS basis). Softwood bedding was barely degradable and diluted the energy production of the stall waste; however, it did not cause inhibition of methane production from manure. Manually separated used softwood bedding contained substantial methane potential.

  14. Methane dissociation process in inductively coupled Ar/H2/CH4 plasma for graphene nano-flakes production

    NASA Astrophysics Data System (ADS)

    Mohanta, Antaryami; Lanfant, Briac; Asfaha, Mehari; Leparoux, Marc

    2017-02-01

    The role of hydrogen and methane dissociation process in induction plasma synthesis of graphene nano-flakes (GNF) is studied by the optical emission spectroscopy of Ar/H2/CH4 plasma. The condensation of C2 species formed due to methane decomposition produces GNF, which depends on pressure. Electron impact and dehydrogenation processes dissociate methane, which promotes and hinders the GNF production, respectively. The effect of hydrogen is insignificant on quality, size and morphology of the GNF. The CH4 flow rate has no influence on particle temperature but has effect on cooling rate at the point of nucleation and, therefore, on production rate and thickness of GNF.

  15. An ecosystem simulation model for methane production and emission from wetlands

    NASA Astrophysics Data System (ADS)

    Potter, Christopher S.

    1997-12-01

    Previous experimental studies suggest that methane emission from wetlands is influenced by multiple interactive pathways of gas production and transport through soil and sediment layers to the atmosphere. The objective of this study is to evaluate a new simulation model of methane production and emission in wetland soils that was developed initially to help identify key processes that regulate methanogenesis and net flux of CH4 to the air but which is designed ultimately for regional simulation using remotely sensed inputs for land cover characteristics. The foundation for these computer simulations is based on a well-documented model (Carnegie-Ames-Stanford Approach, CASA) of ecosystem production and carbon cycling in the terrestrial biosphere. Modifications to represent flooded wetland soils and anaerobic decomposition include three new submodels for (1) layered soil temperature and water table depth (WTD) as a function of daily climate drivers, (2) CH4 production within the anoxic soil layer as a function of WTD and CO2 production under poorly drained conditions, and (3) CH4 gaseous transport pathways (molecular diffusion, ebullition, and plant vascular transport) as a function of WTD and ecosystem type. The model was applied and tested using climate and ecological data to characterize tundra wetland sites near Fairbanks, Alaska, studied previously by Whalen and Reeburgh [1992]. Comparison of model predictions to measurements of soil temperature and thaw depth, water table depth, and CH4 emissions over a 2-year period suggest that intersite differences in soil physical conditions and methane fluxes could be reproduced accurately for selected periods. Day-to-day comparison of predicted emissions to measured CH4 flux rates reveals good agreement during the early part of the thaw season, but the model tends to underestimate production of CH4 during the months of July and August in both test years. Important seasonal effects, including that of falling WTD during

  16. An Ecosystem Simulation Model for Methane Production and Emission from Wetlands

    NASA Technical Reports Server (NTRS)

    Potter, C. S.; Peterson, David L. (Technical Monitor)

    1997-01-01

    Previous experimental studies suggest that methane emission from wetland is influenced by multiple interactive pathways of gas production and transport through soil and sediment layers to the atmosphere. The objective of this study is to evaluate a new simulation model of methane production and emission in wetland soils that was developed initially to help identify key processes that regulate methanogenesis and net flux of CH4 to the air, but which is designed ultimately for regional simulation using remotely sensed inputs for land cover characteristics. The foundation for these computer simulations is based on a well-documented model (CASA) of ecosystem production and carbon cycling in the terrestrial blaspheme. Modifications to represent flooded wetland soils and anaerobic decomposition include three new sub-models for: (1) layered soil temperature and water table depth (WTD) as a function of daily climate drivers, (2) CH4 production within the anoxic soil layer as a function of WTD and CO2 production under poorly drained conditions, and (3) CH4 gaseous transport pathways (molecular diffusion, ebullition, and plant vascular transport) as a function of WTD and ecosystem type. The model was applied and tested using climate and ecological data to characterize tundra wetland sites near Fairbanks, Alaska studied previously by Whalen and Reeburgh. Comparison of model predictions to measurements of soil temperature and thaw depth, water-table depth, and CH4 emissions over a two year period suggest that inter-site differences in soil physical conditions and methane fluxes could be reproduced accurately for selected periods. Day-to-day comparison of predicted emissions to measured CH4 flux rates reveals good agreement during the early part of the thaw season, but the model tends to underestimate production of CH4 during the months of July and August in both test years. Important seasonal effects, including that of falling WTD during these periods, are apparently

  17. On the relationship between methane production and oxidation by anaerobic methanotrophic communities from cold seeps of the Gulf of Mexico.

    PubMed

    Orcutt, Beth; Samarkin, Vladimir; Boetius, Antje; Joye, Samantha

    2008-05-01

    The anaerobic oxidation of methane (AOM) in the marine subsurface is a significant sink for methane in the environment, yet our understanding of its regulation and dynamics is still incomplete. Relatively few groups of microorganisms consume methane in subsurface environments--namely the anaerobic methanotrophic archaea (ANME clades 1, 2 and 3), which are phylogenetically related to methanogenic archaea. Anaerobic oxidation of methane presumably proceeds via a 'reversed' methanogenic pathway. The ANME are generally associated with sulfate-reducing bacteria (SRB) and sulfate is the only documented final electron acceptor for AOM in marine sediments. Our comparative study explored the coupling of AOM with sulfate reduction (SR) and methane generation (MOG) in microbial communities from Gulf of Mexico cold seep sediments that were naturally enriched with methane and other hydrocarbons. These sediments harbour a variety of ANME clades and SRB. Following enrichment under an atmosphere of methane, AOM fuelled 50-100% of SR, even in sediment slurries containing petroleum-associated hydrocarbons and organic matter. In the presence of methane and sulfate, the investigated microbial communities produce methane at a small fraction ( approximately 10%) of the AOM rate. Anaerobic oxidation of methane, MOG and SR rates decreased significantly with decreasing concentration of methane, and in the presence of the SR inhibitor molybdate, but reacted differently to the MOG inhibitor 2-bromoethanesulfonate (BES). The addition of acetate, a possible breakdown product of petroleum in situ and a potential intermediate in AOM/SR syntrophy, did not suppress AOM activity; rather acetate stimulated microbial activity in oily sediment slurries.

  18. Monitoring Production of Methane from Spills of Gasoline at UST Release Sites (Boston, MA)

    EPA Science Inventory

    Anaerobic biodegradation of the BTEX compounds can produce substantial concentrations of methane in ground water at gasoline spill sites. This methane can escape the ground water, move through the unsaturated zone and potentially produce explosive concentrations of methane in c...

  19. Impact of reduced water consumption on sulfide and methane production in rising main sewers.

    PubMed

    Sun, Jing; Hu, Shihu; Sharma, Keshab Raj; Bustamante, Heriberto; Yuan, Zhiguo

    2015-05-01

    Reduced water consumption (RWC), for water conservation purposes, is expected to change the wastewater composition and flow conditions in sewer networks and affect the in-sewer transformation processes. In this study, the impact of reduced water consumption on sulfide and methane production in rising main sewers was investigated. Two lab-scale rising main sewer systems fed with wastewater of different strength and flow rates were operated to mimic sewers under normal and RWC conditions (water consumption reduced by 40%). Sulfide concentration under the RWC condition increased by 0.7-8.0 mg-S/L, depending on the time of a day. Batch test results showed that the RWC did not change the sulfate-reducing activity of sewer biofilms, the increased sulfide production being mainly due to longer hydraulic retention time (HRT). pH in the RWC system was about 0.2 units lower than that in the normal system, indicating that more sulfide would be in molecular form under the RWC condition, which would result in increased sulfide emission to the atmosphere as confirmed by the model simulation. Model based analysis showed that the cost for chemical dosage for sulfide mitigation would increase significantly per unit volume of sewage, although the total cost would decrease due to a lower sewage flow. The dissolved methane concentration under the RWC condition was over two times higher than that under the normal flow condition and the total methane discharge was about 1.5 times higher, which would potentially result in higher greenhouse gas emissions. Batch tests showed that the methanogenic activity of sewer biofilms increased under the RWC condition, which along with the longer HRT, led to increased methane production.

  20. Contribution of oil and natural gas production to renewed increase of atmospheric methane (2007-2014): top-down estimate from ethane and methane column observations

    NASA Astrophysics Data System (ADS)

    Hausmann, P.; Sussmann, R.; Smale, D.

    2015-12-01

    Harmonized time series of column-averaged mole fractions of atmospheric methane and ethane over the period 1999-2014 are derived from solar Fourier transform infrared (FTIR) measurements at the Zugspitze summit (47° N, 2964 m a.s.l.) and at Lauder (45° S, 370 m a.s.l.). Long-term trend analysis reveals a consistent renewed methane increase since 2007 of 6.2 [5.6, 6.9] ppb yr-1 at the Zugspitze and 6.0 [5.3, 6.7] ppb yr-1 at Lauder (95 % confidence intervals). Several recent studies provide pieces of evidence that the renewed methane increase is most likely driven by two main factors: (i) increased methane emissions from tropical wetlands, followed by (ii) increased thermogenic methane emissions due to growing oil and natural gas production. Here, we quantify the magnitude of the second class of sources, using long-term measurements of atmospheric ethane as tracer for thermogenic methane emissions. In 2007, after years of weak decline, the Zugspitze ethane time series shows the sudden onset of a significant positive trend (2.3 [1.8, 2.8] × 10-2 ppb yr-1 for 2007-2014), while a negative trend persists at Lauder after 2007 (-0.4 [-0.6, -0.1] × 10-2 ppb yr-1). Zugspitze methane and ethane time series are significantly correlated for the period 2007-2014 and can be assigned to thermogenic methane emissions with an ethane-to-methane ratio of 10-21 %. We present optimized emission scenarios for 2007-2014 derived from an atmospheric two-box model. From our trend observations we infer a total ethane emission increase over the period 2007-2014 from oil and natural gas sources of 1-11 Tg yr-1 along with an overall methane emission increase of 24-45 Tg yr-1. Based on these results, the oil and natural gas emission contribution C to the renewed methane increase is deduced using three different emission scenarios with dedicated ranges of methane-to-ethane ratios (MER). Reference scenario 1 assumes an oil and gas emission combination with MER = 3.3-7.6, which results in a

  1. Use of 13C-Labeled Substrates to Determine Relative Methane Production Rates in Hypersaline Microbial Communities

    NASA Astrophysics Data System (ADS)

    Kelley, C. A.; Bebout, B.; Chanton, J.

    2015-12-01

    Rates and pathways of methane production were determined from photosynthetic soft microbial mats and gypsum-encrusted endoevaporites collected in hypersaline environments from California, Mexico and Chile, as well as an organic-rich mud from a pond in the El Tatio volcanic fields, Chile. Samples (mud, homogenized soft mats and endoevaporites) were incubated anaerobically with deoxygenated site water, and the increase in methane concentration through time in the headspaces of the incubation vials was used to determine methane production rates. To ascertain the substrates used by the methanogens, 13C-labeled methylamines, methanol, dimethylsulfide, acetate or bicarbonate were added to the incubations (one substrate per vial) and the stable isotopic composition of the resulting methane was measured. The vials amended with 13C-labeled methylamines produced the most 13C-enriched methane, generally followed by the 13C-labeled methanol-amended vials. The stable isotope data and the methane production rates were used to determine first order rate constants for each of the substrates at each of the sites. Estimates of individual substrate use revealed that the methylamines produced 55 to 92% of the methane generated, while methanol was responsible for another 8 to 40%.

  2. Diamond dissolution and the production of methane and other carbon-bearing species in hydrothermal diamond-anvil cells

    USGS Publications Warehouse

    Chou, I.-Ming; Anderson, Alan J.

    2009-01-01

    Raman analysis of the vapor phase formed after heating pure water to near critical (355-374 ??C) temperatures in a hydrothermal diamond-anvil cell (HDAC) reveals the synthesis of abiogenic methane. This unexpected result demonstrates the chemical reactivity of diamond at relatively low temperatures. The rate of methane production from the reaction between water and diamond increases with increasing temperature and is enhanced by the presence of a metal gasket (Re, Ir, or Inconel) which is compressed between the diamond anvils to seal the aqueous sample. The minimum detection limit for methane using Raman spectroscopy was determined to be ca. 0.047 MPa, indicating that more than 1.4 nanograms (or 8.6 ?? 10-11 mol) of methane were produced in the HDAC at 355 ??C and 30 MPa over a period of ten minutes. At temperatures of 650 ??C and greater, hydrogen and carbon dioxide were detected in addition to methane. The production of abiogenic methane, observed in all HDAC experiments where a gasket was used, necessitates a reexamination of the assumed chemical systems and intensive parameters reported in previous hydrothermal investigations employing diamonds. The results also demonstrate the need to minimize or eliminate the production of methane and other carbonic species in experiments by containing the sample within a HDAC without using a metal gasket.

  3. Methane as a product of chloroethene biodegradation under methanogenic conditions

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.

    1999-01-01

    Radiometric detection headspace analyses of microcosms containing bed sediments from two geographically distinct sites indicated that 10-39% of the radiolabeled carbon transformed during anaerobic biodegradation of [1,2- 14C]trichloroethene (TCE) or [1,2-14C]vinyl chloride (VC) under methanogenic conditions was ultimately incorporated into 14CH4. The results demonstrate that, in addition to ethene, ethane, and CO2, CH4 can be a significant product of chloroethene biodegradation in some methanogenic sediments.Radiometric detection headspace analyses of microcosms containing bed sediments from two geographically distinct sites indicated that 10-39% of the radiolabeled carbon transformed during anaerobic biodegradation of [1,2-14C]trichloroethene (TCE) or [1,2-14C]vinyl chloride (VC) under methanogenic conditions was ultimately incorporated into 14CH4. The results demonstrate that, in addition to ethene, ethane, and CO2, CH4 can be a significant product of chloroethene biodegradation in some methanogenic sediments.

  4. To what extent can biogenic SOA be controlled?

    PubMed

    Carlton, Annmarie G; Pinder, Robert W; Bhave, Prakash V; Pouliot, George A

    2010-05-01

    The implicit assumption that biogenic secondary organic aerosol (SOA) is natural and can not be controlled hinders effective air quality management. Anthropogenic pollution facilitates transformation of naturally emitted volatile organic compounds (VOCs) to the particle phase, enhancing the ambient concentrations of biogenic secondary organic aerosol (SOA). It is therefore conceivable that some portion of ambient biogenic SOA can be removed by controlling emissions of anthropogenic pollutants. Direct measurement of the controllable fraction of biogenic SOA is not possible, but can be estimated through 3-dimensional photochemical air quality modeling. To examine this in detail, 22 CMAQ model simulations were conducted over the continental U.S. (August 15 to September 4, 2003). The relative contributions of five emitted pollution classes (i.e., NO(x), NH(3), SO(x), reactive non methane carbon (RNMC) and primary carbonaceous particulate matter (PCM)) on biogenic SOA were estimated by removing anthropogenic emissions of these pollutants, one at a time and all together. Model results demonstrate a strong influence of anthropogenic emissions on predicted biogenic SOA concentrations, suggesting more than 50% of biogenic SOA in the eastern U.S. can be controlled. Because biogenic SOA is substantially enhanced by controllable emissions, classification of SOA as biogenic or anthropogenic based solely on VOC origin is not sufficient to describe the controllable fraction.

  5. Simultaneous enhancement of methane production and methane content in biogas from waste activated sludge and perennial ryegrass anaerobic co-digestion: The effects of pH and C/N ratio.

    PubMed

    Dai, Xiaohu; Li, Xiaoshuai; Zhang, Dong; Chen, Yinguang; Dai, Lingling

    2016-09-01

    It is necessary to find an appropriate strategy to simultaneously enhance the methane production and methane content in biogas from waste activated sludge (WAS) and grass co-digestion. In this study an efficient strategy, i.e., adjusting the initial pH 12 and C/N ratio 17/1, for simultaneous enhancement of methane production and methane content in biogas from WAS and perennial ryegrass co-digestion was reported. Experimental results indicated that the maximal methane production was 310mL/gVSadd at the optimum conditions after 30-d anaerobic digestion, which was, respectively, about 1.5- and 3.8-fold of the sole WAS and sole perennial ryegrass anaerobic digestion. Meanwhile, the methane content in biogas was about 74%, which was much higher than that of sole WAS (64%) or sole perennial ryegrass (54%) anaerobic digestion.

  6. Production of biogenic amines by lactic acid bacteria and enterobacteria isolated from fresh pork sausages packaged in different atmospheres and kept under refrigeration.

    PubMed

    Curiel, J A; Ruiz-Capillas, C; de Las Rivas, B; Carrascosa, A V; Jiménez-Colmenero, F; Muñoz, R

    2011-07-01

    The occurrence of in vitro amino acid activity in bacterial strains associated with fresh pork sausages packaged in different atmospheres and kept in refrigeration was studied. The presence of biogenic amines in decarboxylase broth was confirmed by ion-exchange chromatography and by the presence of the corresponding decarboxylase genes by PCR. From the 93 lactic acid bacteria and 100 enterobacteria strains analysed, the decarboxylase medium underestimates the number of biogenic amine-producer strains. 28% of the lactic acid bacteria produced tyramine and presented the tdc gene. All the tyramine-producer strains were molecularly identified as Carnobacterium divergens. Differences on the relative abundance of C. divergens were observed among the different packaging atmospheres assayed. After 28 days of storage, the presence of argon seems to inhibit C. divergens growth, while packing under vacuum seems to favour it. Among enterobacteria, putrescine was the amine more frequently produced (87%), followed by cadaverine (85%); agmatine and tyramine were only produced by 13 and 1%, respectively, of the strains analysed. Packing under vacuum or in an atmosphere containing nitrogen seems to inhibit the growth of enterobacteria which produce simultaneously putrescine, cadaverine, and agmatine. Contrarily, over-wrapping or packing in an atmosphere containing argon seems to favour the growth of agmatine producer-enterobacteria. The production of putrescine and cadaverine was associated with the presence of the corresponding amino acid decarboxylase genes. The biogenic amine-producer strains were included in a wide range of enterobacterial species, including Kluyvera intermedia, Enterobacter aerogenes, Yersinia kristensenii, Serratia grimesii, Serratia ficaria, Yersinia rodhei, Providencia vermicola and Obesumbacterium proteus.

  7. Massive production of abiotic methane during subduction evidenced in metamorphosed ophicarbonates from the Italian Alps

    PubMed Central

    Vitale Brovarone, Alberto; Martinez, Isabelle; Elmaleh, Agnès; Compagnoni, Roberto; Chaduteau, Carine; Ferraris, Cristiano; Esteve, Imène

    2017-01-01

    Alteration of ultramafic rocks plays a major role in the production of hydrocarbons and organic compounds via abiotic processes on Earth and beyond and contributes to the redistribution of C between solid and fluid reservoirs over geological cycles. Abiotic methanogenesis in ultramafic rocks is well documented at shallow conditions, whereas natural evidence at greater depths is scarce. Here we provide evidence for intense high-pressure abiotic methanogenesis by reduction of subducted ophicarbonates. Protracted (≥0.5–1 Ma), probably episodic infiltration of reduced fluids in the ophicarbonates and methanogenesis occurred from at least ∼40 km depth to ∼15–20 km depth. Textural, petrological and isotopic data indicate that methane reached saturation triggering the precipitation of graphitic C accompanied by dissolution of the precursor antigorite. Continuous infiltration of external reducing fluids caused additional methane production by interaction with the newly formed graphite. Alteration of high-pressure carbonate-bearing ultramafic rocks may represent an important source of abiotic methane, with strong implications for the mobility of deep C reservoirs. PMID:28223715

  8. Biological hydrogen and methane production from bagasse bioethanol fermentation residues using a two-stage bioprocess.

    PubMed

    Cheng, Hai-Hsuan; Whang, Liang-Ming; Chung, Man-Chien; Chan, Kun-Chi

    2016-06-01

    This study investigated the recovery of H2 and CH4 from bagasse bioethanol fermentation residues (bagasse BEFR) using a two-stage bioprocess. In the hydrogen fermentation bioreactor (HFB), carbohydrate removal efficiency was maintained at 82-93% and the highest hydrogen yield was 8.24mL/gCOD at volumetric loading rate (VLR) of 80kgCOD/m(3)/day. The results indicated a positive correlation between hydrogen yield and butyrate-to-acetate ratio, which might be due to the mechanisms of lactate/acetate utilization for hydrogen production and acetogenesis occurring in the HFB. Remaining volatile fatty acids and alcohols in the HFB effluent were further utilized for methane production in methane fermentation bioreactor (MFB), in which the highest methane yield of 345.2mL/gCOD was attained at VLR of 2.5kgCOD/m(3)/day. Overall, the two-stage bioprocess achieved a maximum COD removal of 81% from bagasse BEFR, and converted 0.3% and 72.8% of COD in the forms of H2 and CH4, respectively.

  9. Estimating methane production rates in bogs and landfills by deuterium enrichment of pore water

    USGS Publications Warehouse

    Siegel, D.I.; Chanton, J.P.; Glaser, P.H.; Chasar, L.S.; Rosenberry, D.O.

    2001-01-01

    Raised bogs and municipal waste landfills harbor large populations of methanogens within their domed deposits of anoxic organic matter. Although the methane emissions from these sites have been estimated by various methods, limited data exist on the activity of the methanogens at depth. We therefore analyzed the stable isotopic signature of the pore waters in two raised bogs from northern Minnesota to identify depth intervals in the peat profile where methanogenic metabolism occurs. Methanogenesis enriched the deuterium (2H) content of the deep peat pore waters by as much as +11% (Vienna Standard Mean Sea Water), which compares to a much greater enrichment factor of +70% in leachate from New York City's Fresh Kills landfill. The bog pore waters were isotopically dated by tritium (3H) to be about 35 years old at 1.5 m depth, whereas the landfill leachate was estimated as ~ 17 years old from Darcy flow calculations. According to an isotopic mass balance the observed deuterium enrichment indicates that about 1.2 g of CH4m-3 d-1 were produced within the deeper peat, compared to about 2.8 g CH4 m-3 d-1 in the landfill. The values for methane production in the bog peat are substantially higher than the flux rates measured at the surface of the bogs or at the landfill, indicating that deeper methane production may be much higher than was previously assumed.

  10. Hydrogen production by coupled catalytic partial oxidation and steam methane reforming at elevated pressure and temperature

    NASA Astrophysics Data System (ADS)

    Chen, Luwei; Hong, Qi; Lin, Jianyi; Dautzenberg, F. M.

    Hydrogen production by coupled catalytic partial oxidation (CPO) and steam methane reforming of methane (OSMR) at industrial conditions (high temperatures and pressures) have been studied over supported 1 wt.% NiB catalysts. Mixture of air/CH 4/H 2O was applied as the feed. The effects of O 2:CH 4 ratio, H 2O:CH 4 ratio and the gas hourly space velocity (GHSV) on oxy-steam reforming (OSRM) were also studied. Results indicate that CH 4 conversion increases significantly with increasing O 2:CH 4 or H 2O:CH 4 ratio. However, the hydrogen mole fraction goes through a maximum, depending on reaction conditions, e.g., pressure, temperature and the feed gases ratios. Carbon deposition on the catalysts has been greatly decreased after steam addition. The supported 1 wt.% NiB catalysts exhibit high stability with 85% methane conversion at 15 bar and 800 °C during 70 h time-on-stream reaction (CH 4:O 2:H 2O:N 2 = 1:0.5:1:1.887). The thermal efficiency was increased from 35.8% by CPO (without steam) to 55.6%. The presented data would be useful references for further design of enlarged scale hydrogen production system.

  11. Methane emissions from process equipment at natural gas production sites in the United States: liquid unloadings.

    PubMed

    Allen, David T; Sullivan, David W; Zavala-Araiza, Daniel; Pacsi, Adam P; Harrison, Matthew; Keen, Kindal; Fraser, Matthew P; Daniel Hill, A; Lamb, Brian K; Sawyer, Robert F; Seinfeld, John H

    2015-01-06

    Methane emissions from liquid unloadings were measured at 107 wells in natural gas production regions throughout the United States. Liquid unloadings clear wells of accumulated liquids to increase production, employing a variety of liquid lifting mechanisms. In this work, wells with and without plunger lifts were sampled. Most wells without plunger lifts unload less than 10 times per year with emissions averaging 21,000-35,000 scf methane (0.4-0.7 Mg) per event (95% confidence limits of 10,000-50,000 scf/event). For wells with plunger lifts, emissions averaged 1000-10,000 scf methane (0.02-0.2 Mg) per event (95% confidence limits of 500-12,000 scf/event). Some wells with plunger lifts are automatically triggered and unload thousands of times per year and these wells account for the majority of the emissions from all wells with liquid unloadings. If the data collected in this work are assumed to be representative of national populations, the data suggest that the central estimate of emissions from unloadings (270 Gg/yr, 95% confidence range of 190-400 Gg) are within a few percent of the emissions estimated in the EPA 2012 Greenhouse Gas National Emission Inventory (released in 2014), with emissions dominated by wells with high frequencies of unloadings.

  12. Massive production of abiotic methane during subduction evidenced in metamorphosed ophicarbonates from the Italian Alps

    NASA Astrophysics Data System (ADS)

    Vitale Brovarone, Alberto; Martinez, Isabelle; Elmaleh, Agnès; Compagnoni, Roberto; Chaduteau, Carine; Ferraris, Cristiano; Esteve, Imène

    2017-02-01

    Alteration of ultramafic rocks plays a major role in the production of hydrocarbons and organic compounds via abiotic processes on Earth and beyond and contributes to the redistribution of C between solid and fluid reservoirs over geological cycles. Abiotic methanogenesis in ultramafic rocks is well documented at shallow conditions, whereas natural evidence at greater depths is scarce. Here we provide evidence for intense high-pressure abiotic methanogenesis by reduction of subducted ophicarbonates. Protracted (>=0.5-1 Ma), probably episodic infiltration of reduced fluids in the ophicarbonates and methanogenesis occurred from at least ~40 km depth to ~15-20 km depth. Textural, petrological and isotopic data indicate that methane reached saturation triggering the precipitation of graphitic C accompanied by dissolution of the precursor antigorite. Continuous infiltration of external reducing fluids caused additional methane production by interaction with the newly formed graphite. Alteration of high-pressure carbonate-bearing ultramafic rocks may represent an important source of abiotic methane, with strong implications for the mobility of deep C reservoirs.

  13. Massive production of abiotic methane during subduction evidenced in metamorphosed ophicarbonates from the Italian Alps.

    PubMed

    Vitale Brovarone, Alberto; Martinez, Isabelle; Elmaleh, Agnès; Compagnoni, Roberto; Chaduteau, Carine; Ferraris, Cristiano; Esteve, Imène

    2017-02-22

    Alteration of ultramafic rocks plays a major role in the production of hydrocarbons and organic compounds via abiotic processes on Earth and beyond and contributes to the redistribution of C between solid and fluid reservoirs over geological cycles. Abiotic methanogenesis in ultramafic rocks is well documented at shallow conditions, whereas natural evidence at greater depths is scarce. Here we provide evidence for intense high-pressure abiotic methanogenesis by reduction of subducted ophicarbonates. Protracted (≥0.5-1 Ma), probably episodic infiltration of reduced fluids in the ophicarbonates and methanogenesis occurred from at least ∼40 km depth to ∼15-20 km depth. Textural, petrological and isotopic data indicate that methane reached saturation triggering the precipitation of graphitic C accompanied by dissolution of the precursor antigorite. Continuous infiltration of external reducing fluids caused additional methane production by interaction with the newly formed graphite. Alteration of high-pressure carbonate-bearing ultramafic rocks may represent an important source of abiotic methane, with strong implications for the mobility of deep C reservoirs.

  14. Variation in methane production pathways associated with permafrost decomposition in collapse scar bogs of Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Prater, James L.; Chanton, Jeffrey P.; Whiting, Gary J.

    2007-12-01

    Stable isotope analysis was used to determine the distribution of methanogenic pathways at permafrost collapse scar bogs to test the hypothesis that microbial respiration and methane production are stimulated by the input of organic matter associated with permafrost degradation and collapse. An alternative hypothesis is that recently assimilated carbon produced by the fen-like vegetation (Carex, Eriophorum) growing in open water moats formed by the collapsing edge of these features stimulates microbial respiration. We found that CO2 reduction was the dominant pathway for methanogenesis within the Sphagnum areas that dominate the surface cover of these features, but relatively more acetate fermentation occurred near collapse scar moats. Methane emission and net CO2 uptake were correlated. Both were elevated in collapse scar moats and then decreased along a transect from the moats toward the center Sphagnum-dominated areas. There also appeared to be a shift toward relatively more acetate fermentation in deeper samples associated with increasing cation (calcium and magnesium) concentrations. Our results indicate that organic inputs from permafrost degradation alone do not appear to stimulate acetate fermentation. Permafrost decomposition provides conditions along the collapsing edge that are conducive to colonization by fen-like vegetation that stimulates acetate fermentation and increases methane production and emission rates.

  15. Effect of nutrient and selective inhibitor amendments on methane oxidation, nitrous oxide production, and key gene presence and expression in landfill cover soils: characterization of the role of methanotrophs, nitrifiers, and denitrifiers.

    PubMed

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

    2009-11-01

    Methane and nitrous oxide are both potent greenhouse gasses, with global warming potentials approximately 25 and 298 times that of carbon dioxide. A matrix of soil microcosms was constructed with landfill cover soils collected from the King Highway Landfill in Kalamazoo, Michigan and exposed to geochemical parameters known to affect methane consumption by methanotrophs while also examining their impact on biogenic nitrous oxide production. It was found that relatively dry soils (5% moisture content) along with 15 mg NH (4) (+) (kg soil)(-1) and 0.1 mg phenylacetylene(kg soil)(-1) provided the greatest stimulation of methane oxidation while minimizing nitrous oxide production. Microarray analyses of pmoA showed that the methanotrophic community structure was dominated by Type II organisms, but Type I genera were more evident with the addition of ammonia. When phenylacetylene was added in conjunction with ammonia, the methanotrophic community structure was more similar to that observed in the presence of no amendments. PCR analyses showed the presence of amoA from both ammonia-oxidizing bacteria and archaea, and that the presence of key genes associated with these cells was reduced with the addition of phenylacetylene. Messenger RNA analyses found transcripts of pmoA, but not of mmoX, nirK, norB, or amoA from either ammonia-oxidizing bacteria or archaea. Pure culture analyses showed that methanotrophs could produce significant amounts of nitrous oxide, particularly when expressing the particulate methane monooxygenase (pMMO). Collectively, these data suggest that methanotrophs expressing pMMO played a role in nitrous oxide production in these microcosms.

  16. Effect of catalytic cylinders on autothermal reforming of methane for hydrogen production in a microchamber reactor.

    PubMed

    Yan, Yunfei; Guo, Hongliang; Zhang, Li; Zhu, Junchen; Yang, Zhongqing; Tang, Qiang; Ji, Xin

    2014-01-01

    A new multicylinder microchamber reactor is designed on autothermal reforming of methane for hydrogen production, and its performance and thermal behavior, that is, based on the reaction mechanism, is numerically investigated by varying the cylinder radius, cylinder spacing, and cylinder layout. The results show that larger cylinder radius can promote reforming reaction; the mass fraction of methane decreased from 26% to 21% with cylinder radius from 0.25 mm to 0.75 mm; compact cylinder spacing corresponds to more catalytic surface and the time to steady state is decreased from 40 s to 20 s; alteration of staggered and aligned cylinder layout at constant inlet flow rates does not result in significant difference in reactor performance and it can be neglected. The results provide an indication and optimize performance of reactor; it achieves higher conversion compared with other reforming reactors.

  17. Production of the hydrogen by methane steam reforming over nickel catalysts prepared from hydrotalcite precursors

    NASA Astrophysics Data System (ADS)

    Fonseca, Alessandra; Assaf, Elisabete M.

    Catalysts were prepared from hydrotalcite precursors, characterized and tested in the reaction of methane steam reforming to produce hydrogen. The precursors were synthesized by: the traditional technique, with co-precipitation of Ni, Mg and Al nitrates with carbonate; co-precipitation of Mg and Al nitrates with pre-synthesized nickel chelate and anion-exchange of NO 3- of hydrotalcite with nickel chelate. The oxides were analyzed using atomic absorption spectrophotometry, specific surface area, X-ray diffraction (XRD), temperature programmed reduction (TPR) with H 2, catalytic tests and elemental analysis. The catalytic tests demonstrated high methane conversion, high activity for hydrogen production and high stability during the time of reaction for a molar ratio in the feed H 2O:CH 4 = 2:1.

  18. Effect of Catalytic Cylinders on Autothermal Reforming of Methane for Hydrogen Production in a Microchamber Reactor

    PubMed Central

    Yan, Yunfei; Guo, Hongliang; Zhang, Li; Zhu, Junchen; Yang, Zhongqing; Tang, Qiang; Ji, Xin

    2014-01-01

    A new multicylinder microchamber reactor is designed on autothermal reforming of methane for hydrogen production, and its performance and thermal behavior, that is, based on the reaction mechanism, is numerically investigated by varying the cylinder radius, cylinder spacing, and cylinder layout. The results show that larger cylinder radius can promote reforming reaction; the mass fraction of methane decreased from 26% to 21% with cylinder radius from 0.25 mm to 0.75 mm; compact cylinder spacing corresponds to more catalytic surface and the time to steady state is decreased from 40 s to 20 s; alteration of staggered and aligned cylinder layout at constant inlet flow rates does not result in significant difference in reactor performance and it can be neglected. The results provide an indication and optimize performance of reactor; it achieves higher conversion compared with other reforming reactors. PMID:25097877

  19. Prototype demonstration studies of production of methane from municipal solid waste at Pompano Beach, Florida

    SciTech Connect

    Faroog, S.; Daly, E.; Dasgupta, A.; Gerrish, M.P.; Sengupta, S.; Wong, K.F.

    1980-12-01

    A prototype demonstration plant for the production of methane from anaerobic digestion of municipal solid waste in amounts up to 100 tons per day is built at Pompano Beach, Florida. The plant is capable of producing 6000 ft/sup 3/ of gas per ton of municipal waste. Approximately half of the gas is methane, the other half CO/sub 2/ along with some trace gases. In this plant the raw municipal solid waste is shredded, ferrous metals removed magnetically and air classified to obtain an organic-rich light weight fraction, which is periodically mixed with sewage sludge and fed into the anaerobic digester. The processed effluent is filtered in a vacuum filter and the emerging filter cake is disposed on the nearby existing sanitary landfill. The filtrate is recirculated into the digester. Various gas, solid and liquid streams coming out of the digester are analyzed for physical, chemical and biological pollution parameters.

  20. Carbon and nitrogen removal and enhanced methane production in a microbial electrolysis cell.

    PubMed

    Villano, Marianna; Scardala, Stefano; Aulenta, Federico; Majone, Mauro

    2013-02-01

    The anode of a two-chamber methane-producing microbial electrolysis cell (MEC) was poised at +0.200V vs. the standard hydrogen electrode (SHE) and continuously fed (1.08gCOD/Ld) with acetate in anaerobic mineral medium. A gas mixture (carbon dioxide 30vol.% in N(2)) was continuously added to the cathode for both pH control and carbonate supply. At the anode, 94% of the influent acetate was removed, mostly through anaerobic oxidation (91% coulombic efficiency); the resulting electric current was mainly recovered as methane (79% cathode capture efficiency). Low biomass growth was observed at the anode and ammonium was transferred through the cationic membrane and concentrated at the cathode. These findings suggest that the MEC can be used for the treatment of low-strength wastewater, with good energy efficiency and low sludge production.

  1. Ancient and methane-derived carbon subsidizes contemporary food webs

    PubMed Central

    DelVecchia, Amanda G.; Stanford, Jack A.; Xu, Xiaomei

    2016-01-01

    While most global productivity is driven by modern photosynthesis, river ecosystems are supplied by locally fixed and imported carbon that spans a range of ages. Alluvial aquifers of gravel-bedded river floodplains present a conundrum: despite no possibility for photosynthesis in groundwater and extreme paucity of labile organic carbon, they support diverse and abundant large-bodied consumers (stoneflies, Insecta: Plecoptera). Here we show that up to a majority of the biomass carbon composition of these top consumers in four floodplain aquifers of Montana and Washington is methane-derived. The methane carbon ranges in age from modern to up to >50,000 years old and is mostly derived from biogenic sources, although a thermogenic contribution could not be excluded. We document one of the most expansive ecosystems to contain site-wide macroinvertebrate biomass comprised of methane-derived carbon and thereby advance contemporary understanding of basal resources supporting riverine productivity. PMID:27824032

  2. Ancient and methane-derived carbon subsidizes contemporary food webs.

    PubMed

    DelVecchia, Amanda G; Stanford, Jack A; Xu, Xiaomei

    2016-11-08

    While most global productivity is driven by modern photosynthesis, river ecosystems are supplied by locally fixed and imported carbon that spans a range of ages. Alluvial aquifers of gravel-bedded river floodplains present a conundrum: despite no possibility for photosynthesis in groundwater and extreme paucity of labile organic carbon, they support diverse and abundant large-bodied consumers (stoneflies, Insecta: Plecoptera). Here we show that up to a majority of the biomass carbon composition of these top consumers in four floodplain aquifers of Montana and Washington is methane-derived. The methane carbon ranges in age from modern to up to >50,000 years old and is mostly derived from biogenic sources, although a thermogenic contribution could not be excluded. We document one of the most expansive ecosystems to contain site-wide macroinvertebrate biomass comprised of methane-derived carbon and thereby advance contemporary understanding of basal resources supporting riverine productivity.

  3. Ancient and methane-derived carbon subsidizes contemporary food webs

    NASA Astrophysics Data System (ADS)

    Delvecchia, Amanda G.; Stanford, Jack A.; Xu, Xiaomei

    2016-11-01

    While most global productivity is driven by modern photosynthesis, river ecosystems are supplied by locally fixed and imported carbon that spans a range of ages. Alluvial aquifers of gravel-bedded river floodplains present a conundrum: despite no possibility for photosynthesis in groundwater and extreme paucity of labile organic carbon, they support diverse and abundant large-bodied consumers (stoneflies, Insecta: Plecoptera). Here we show that up to a majority of the biomass carbon composition of these top consumers in four floodplain aquifers of Montana and Washington is methane-derived. The methane carbon ranges in age from modern to up to >50,000 years old and is mostly derived from biogenic sources, although a thermogenic contribution could not be excluded. We document one of the most expansive ecosystems to contain site-wide macroinvertebrate biomass comprised of methane-derived carbon and thereby advance contemporary understanding of basal resources supporting riverine productivity.

  4. Straw application in paddy soil enhances methane production also from other carbon sources

    NASA Astrophysics Data System (ADS)

    Yuan, Q.; Pump, J.; Conrad, R.

    2013-08-01

    Flooded rice fields are an important source of the greenhouse gas methane. Methane is produced from rice straw (RS), soil organic matter (SOM), and rice root organic carbon (ROC). Addition of RS is widely used for ameliorating soil fertility. However, this practice provides additional substrate for CH4 production and results in increased CH4 emission. Here, we found that decomposing RS is not only a substrate of CH4 production, but in addition stimulates CH4 production from SOM and ROC. Apart from accelerating the creation of reduced conditions in the soil environment, RS decomposition exerted a positive priming effect on SOM-derived CH4 production. In particular, hydrogenotrophic methanogenesis from SOM-derived CO2 was stimulated, presumably by H2 released from RS decomposition. On the other hand, the positive priming effect of RS on ROC-derived CH4 production was probably caused by the significant increase of the abundance of methanogenic archaea in the RS treatment compared with the untreated control. Our results show that traditional management of rice residues exerts a positive feedback on CH4 production from rice fields, thus exacerbating its effect on the global CH4 budget.

  5. Straw application in paddy soil enhances methane production also from other carbon sources

    NASA Astrophysics Data System (ADS)

    Yuan, Q.; Pump, J.; Conrad, R.

    2014-01-01

    Flooded rice fields are an important source of the greenhouse gas methane. Methane is produced from rice straw (RS), soil organic matter (SOM), and rice root organic carbon (ROC). Addition of RS is widely used for ameliorating soil fertility. However, this practice provides additional substrate for CH4 production and results in increased CH4 emission. Here, we found that decomposing RS is not only a substrate of CH4 production, but in addition stimulates CH4 production from SOM and ROC. Apart from accelerating the creation of reduced conditions in the soil environment, RS decomposition resulted in enhancement of SOM-derived CH4 production. In particular, hydrogenotrophic methanogenesis from SOM-derived CO2 was stimulated, presumably by H2 released from RS decomposition. On the other hand, the enhancement of ROC-derived CH4 production after RS application was probably caused by the significant increase of the abundance of methanogenic Archaea in the RS treatment compared with the untreated control. Our results show that traditional management of rice residues exerts a positive feedback on CH4 production from rice fields, thus exacerbating its effect on the global CH4 budget.

  6. Utilization of coal mine methane for methanol and SCP production. Topical report, May 5, 1995--March 4, 1996

    SciTech Connect

    1998-12-31

    The feasibility of utilizing a biological process to reduce methane emissions from coal mines and to produce valuable single cell protein (SCP) and/or methanol as a product has been demonstrated. The quantities of coal mine methane from vent gas, gob wells, premining wells and abandoned mines have been determined in order to define the potential for utilizing mine gases as a resource. It is estimated that 300 MMCFD of methane is produced in the United States at a typical concentration of 0.2-0.6 percent in ventilation air. Of this total, almost 20 percent is produced from the four Jim Walter Resources (JWR) mines, which are located in very gassy coal seams. Worldwide vent gas production is estimated at 1 BCFD. Gob gas methane production in the U.S. is estimated to be 38 MMCFD. Very little gob gas is produced outside the U.S. In addition, it is estimated that abandoned mines may generate as much as 90 MMCFD of methane. In order to make a significant impact on coal mine methane emissions, technology which is able to utilize dilute vent gases as a resource must be developed. Purification of the methane from the vent gases would be very expensive and impractical. Therefore, the process application must be able to use a dilute methane stream. Biological conversion of this dilute methane (as well as the more concentrated gob gases) to produce single cell protein (SCP) and/or methanol has been demonstrated in the Bioengineering Resources, Inc. (BRI) laboratories. SCP is used as an animal feed supplement, which commands a high price, about $0.11 per pound.

  7. Contribution of oil and natural gas production to renewed increase in atmospheric methane (2007-2014): top-down estimate from ethane and methane column observations

    NASA Astrophysics Data System (ADS)

    Hausmann, Petra; Sussmann, Ralf; Smale, Dan

    2016-03-01

    Harmonized time series of column-averaged mole fractions of atmospheric methane and ethane over the period 1999-2014 are derived from solar Fourier transform infrared (FTIR) measurements at the Zugspitze summit (47° N, 11° E; 2964 m a.s.l.) and at Lauder (45° S, 170° E; 370 m a.s.l.). Long-term trend analysis reveals a consistent renewed methane increase since 2007 of 6.2 [5.6, 6.9] ppb yr-1 (parts-per-billion per year) at the Zugspitze and 6.0 [5.3, 6.7] ppb yr-1 at Lauder (95 % confidence intervals). Several recent studies provide pieces of evidence that the renewed methane increase is most likely driven by two main factors: (i) increased methane emissions from tropical wetlands, followed by (ii) increased thermogenic methane emissions due to growing oil and natural gas production. Here, we quantify the magnitude of the second class of sources, using long-term measurements of atmospheric ethane as a tracer for thermogenic methane emissions. In 2007, after years of weak decline, the Zugspitze ethane time series shows the sudden onset of a significant positive trend (2.3 [1.8, 2.8] × 10-2 ppb yr-1 for 2007-2014), while a negative trend persists at Lauder after 2007 (-0.4 [-0.6, -0.1] × 10-2 ppb yr-1). Zugspitze methane and ethane time series are significantly correlated for the period 2007-2014 and can be assigned to thermogenic methane emissions with an ethane-to-methane ratio (EMR) of 12-19 %. We present optimized emission scenarios for 2007-2014 derived from an atmospheric two-box model. From our trend observations we infer a total ethane emission increase over the period 2007-2014 from oil and natural gas sources of 1-11 Tg yr-1 along with an overall methane emission increase of 24-45 Tg yr-1. Based on these results, the oil and natural gas emission contribution (C) to the renewed methane increase is deduced using three different emission scenarios with dedicated EMR ranges. Reference scenario 1 assumes an oil and gas emission combination with EMR = 7

  8. Methane excess production in oxygen-rich polar water and a model of cellular conditions for this paradox

    NASA Astrophysics Data System (ADS)

    Damm, E.; Thoms, S.; Beszczynska-Möller, A.; Nöthig, E. M.; Kattner, G.

    2015-09-01

    Summer sea ice cover in the Arctic Ocean has undergone a reduction in the last decade exposing the sea surface to unforeseen environmental changes. Melting sea ice increases water stratification and induces nutrient limitation, which is also known to play a crucial role in methane formation in oxygenated surface water. We report on an excess of methane in the marginal ice zone in the western Fram Strait. Our study is based on measurements of oxygen, methane, DMSP, nitrate and phosphate concentrations as well as on phytoplankton composition and light transmission, conducted along the 79°N oceanographic transect, in the western part of the Fram Strait and in Northeast Water Polynya region off Greenland. Between the eastern Fram Strait, where Atlantic water enters from the south and the western Fram Strait, where Polar water enters from the north, different nutrient limitations occurred and consequently different bloom conditions were established. Ongoing sea ice melting enhances the environmental differences between both water masses and initiates regenerated production in the western Fram Strait. We show that in this region methane is in situ produced while DMSP (dimethylsulfoniopropionate) released from sea ice may serve as a precursor for the methane formation. The methane production occured despite high oxygen concentrations in this water masses. As the metabolic activity (respiration) of unicellular organisms explains the presence of anaerobic conditions in the cellular environment we present a theoretical model which explains the maintenance of anaerobic conditions for methane formation inside bacterial cells, despite enhanced oxygen concentrations in the environment.

  9. Production of biogenic amines "in vitro" in relation to the growth phase by Enterobacteriaceae species isolated from traditional sausages.

    PubMed

    Lorenzo, José M; Cachaldora, Aida; Fonseca, Sonia; Gómez, María; Franco, Inmaculada; Carballo, Javier

    2010-11-01

    Histidine, lysine, ornithine and tyrosine decarboxylase activities were tested in 79 strains of Enterobacteriaceae (41 of Hafnia alvei, 17 of Serratia liquefaciens, 5 of Enterobacter cloacae, 4 of Citrobacter braakii, 2 of Proteus vulgaris, 2 of Proteus mirabilis, 2 of Providencia stuartii, 2 of Klebsiella terrigena, 1 of Rahnella aquatilis, 1 of Salmonella arizonae, 1 of Citrobacter youngae and 1 of Escherichia coli) isolated from Botillo, a Spanish traditional sausage. In general, the strains were positive for all four activities, with the exception of two strains of H. alvei and the E. coli strain, which did not display histidine decarboxylase activity. The strains of P. mirabilis and P. stuartii did not exhibit any of the four activities tested. Accumulation of putrescine and cadaverine was studied throughout growth of the 75 strains that displayed ornithine and lysine decarboxylase activities. Biogenic amines were produced particularly in the exponential phase, with maximum accumulation occurring after between 12 to 72 h, depending on the biogenic amine and microbial species considered. Maximum accumulation of putrescine varied greatly between species and within the same species, and ranged from 18 mg/l in the R. aquatilis strain to 7325 mg/l in a H. alvei strain. Maximum accumulation of cadaverine varied less than that of putrescine, and ranged from 30 mg/l in the R. aquatilis strain to 1935 mg/l in a S. liquefaciens strain.

  10. Methane as a biomarker in the search for extraterrestrial life: Lessons learned from Mars analog hypersaline environments

    NASA Astrophysics Data System (ADS)

    Bebout, B.; Tazaz, A.; Kelley, C. A.; Poole, J. A.; Davila, A.; Chanton, J.

    2010-12-01

    -60 ‰ to -30 ‰, while the hydrogen isotopic composition (δ2H) ranged from about -350 to -300‰. These isotopic values are outside the range generally considered to be biogenic, however incubations of the sediments and salt crusts revealed that the methane is indeed produced there. The highest rate of methane production was 20 nmol/g/d, in a gypsum crust with endolithic microbial communities. Currently we are studying the mechanisms that control the isotopic signatures of methane in these environments. These studies are of special relevance given the projected analysis of Mars atmospheric methane by the Mars Science Laboratory in 2012, and by the ExoMars Trace Gas Orbiter in 2017.

  11. The benefits of supplementary fat in feed rations for ruminants with particular focus on reducing levels of methane production.

    PubMed

    Rasmussen, J; Harrison, A

    2011-01-01

    Methane (CH4), a highly potent greenhouse gas, has repeatedly been identified as a significant contributor to global warming. In this connection, ruminants, animals that produce large quantities of methane, have been singled out as an area for reduction with regard to their emissions to the atmosphere. In an analysis of recently published data, we identify the underlying mechanisms of methane production in ruminants and focus on the efficacy of different fat sources in terms of their ability to reduce methane production. Specific attention has been placed on in vivo studies involving cattle and sheep, as well as studies based on a large number of animals (>10), recorded over a longer period (>21 days), and employing reliable techniques for the quantification of methane production. Data clearly indicate that supplementary fat, given to ruminants inhibits methane production, with medium-chain fatty acids (laurin, myristic acid) as well as poly-unsaturated fatty acids (linoleic and especially linolenic acid) having a significant effect. It is also apparent that conflicting findings between individual published trials can largely be resolved when one takes into consideration differences in experimental design, the composition of the basic feeds, the fat sources used, and the number of animals involved.

  12. Geologic emissions of methane to the atmosphere.

    PubMed

    Etiope, Giuseppe; Klusman, Ronald W

    2002-12-01

    The atmospheric methane budget is commonly defined assuming that major sources derive from the biosphere (wetlands, rice paddies, animals, termites) and that fossil, radiocarbon-free CH4 emission is due to and mediated by anthropogenic activity (natural gas production and distribution, and coal mining). However, the amount of radiocarbon-free CH4 in the atmosphere, estimated at approximately 20% of atmospheric CH4, is higher than the estimates from statistical data of CH4 emission from fossil fuel related anthropogenic sources. This work documents that significant amounts of "old" methane, produced within the Earth crust, can be released naturally into the atmosphere through gas permeable faults and fractured rocks. Major geologic emissions of methane are related to hydrocarbon production in sedimentary basins (biogenic and thermogenic methane) and, subordinately, to inorganic reactions (Fischer-Tropsch type) in geothermal systems. Geologic CH4 emissions include diffuse fluxes over wide areas, or microseepage, on the order of 10(0)-10(2) mg m(-2) day(-1), and localised flows and gas vents, on the order of 10(2) t y(-1), both on land and on the seafloor. Mud volcanoes producing flows of up to 10(3) t y(-1) represent the largest visible expression of geologic methane emission. Several studies have indicated that methanotrophic consumption in soil may be insufficient to consume all leaking geologic CH4 and positive fluxes into the atmosphere can take place in dry or seasonally cold environments. Unsaturated soils have generally been considered a major sink for atmospheric methane, and never a continuous, intermittent, or localised source to the atmosphere. Although geologic CH4 sources need to be quantified more accurately, a preliminary global estimate indicates that there are likely more than enough sources to provide the amount of methane required to account for the suspected missing source of fossil CH4.

  13. Biogenic and biomass burning sources of acetone to the troposphere

    SciTech Connect

    Atherton, C.S.

    1997-04-01

    Acetone may be an important source of reactive odd hydrogen in the upper troposphere and lower stratosphere. This source of odd hydrogen may affect the concentration of a number of species, including ozone, nitrogen oxides, methane, and others. Traditional, acetone had been considered a by-product of the photochemical oxidation of other species, and had not entered models as a primary emission. However, recent work estimates a global source term of 40-60 Tg acetone/year. Of this, 25% is directly emitted during biomass burning, and 20% is directly emitted by evergreens and other plants. Only 3% is due to anthropogenic/industrial emissions. The bulk of the remainder, 51% of the acetone source, is a secondary product from the oxidation of propane, isobutane, and isobutene. Also, while it is speculated that the oxidation of pinene (a biogenic emission) may also contribute about 6 Tg/year, this term is highly uncertain. Thus, the two largest primary sources of acetone are biogenic emission and biomass burning, with industrial/anthropogenic emissions very small in comparison.

  14. Biohydrogen and methane production via a two-step process using an acid pretreated native microalgae consortium.

    PubMed

    Carrillo-Reyes, Julian; Buitrón, Germán

    2016-12-01

    A native microalgae consortium treated under thermal-acidic hydrolysis was used to produce hydrogen and methane in a two-step sequential process. Different acid concentrations were tested, generating hydrogen and methane yields of up to 45mLH2gVS(-1) and 432mLCH4gVS(-1), respectively. The hydrogen production step solubilized the particulate COD (chemical oxygen demand) up to 30%, creating considerable amounts of volatile fatty acids (up to 10gCODL(-1)). It was observed that lower acid concentration presented higher hydrogen and methane production potential. The results revealed that thermal acid hydrolysis of a native microalgae consortium is a simple but effective strategy for producing hydrogen and methane in the sequential process. In addition to COD removal (50-70%), this method resulted in an energy recovery of up to 15.9kJ per g of volatile solids of microalgae biomass, one of the highest reported.

  15. Enzymatic and metabolic activities of four anaerobic sludges and their impact on methane production from ensiled sorghum forage.

    PubMed

    Sambusiti, C; Rollini, M; Ficara, E; Musatti, A; Manzoni, M; Malpei, F

    2014-03-01

    Biochemical methane potential (BMP) tests were run on ensiled sorghum forage using four inocula (urban, agricultural, mixture of agricultural and urban, granular) and differences on their metabolic and enzymatic activities were also discussed. Results indicate that no significant differences were observed in terms of BMP values (258±14NmLCH4g(-1)VS) with a slightly higher value when agricultural sludge was used as inoculum. Significant differences can be observed among different inocula, in terms of methane production rate. In particular the fastest biomethanization occurred when using the urban sludge (hydrolytic kinetic constant kh=0.146d(-1)) while the slowest one was obtained from the agricultural sludge (kh=0.049d(-1)). Interestingly, positive correlations between the overall enzymatic activities and methane production rates were observed for all sludges, showing that a high enzymatic activity may favour the hydrolysis of complex substrate and accelerate the methanization process of sorghum.

  16. Methane assisted solid oxide co-electrolysis process for syngas production

    NASA Astrophysics Data System (ADS)

    Wang, Yao; Liu, Tong; Lei, Libin; Chen, Fanglin

    2017-03-01

    In this study, methane assisted high temperature steam/CO2 co-electrolysis process is performed on symmetrical cells with a configuration of SFM-SDC/LSGM/SFM-SDC to produce high-quality synthesis gas (syngas, a mixture of H2 and CO). The Nernst potential has been evaluated for solid oxide cells in the methane assisted mode, which is reduced by nearly one order of magnitude through substituting the anode atmosphere from air to methane. The open circuit voltage (OCV) is -0.06 V at 800 °C, and an electrolysis current density of -242 mAcm-2 has been obtained at 850 °C and 0.3 V. Effects of operating conditions on products composition have been revealed by using the chemical equilibrium co-electrolysis model and HSC software. High-quality syngas with high conversion rate of CO2 to CO as well as ideal H2/CO molar ratio of 2 could be achieved in both electrode sides by adjusting appropriate operating conditions. The short-term cell voltage is slightly fluctuant less than 0.05 V at 850 °C and -120 mAcm-2, in which condition carbon deposition has been observed in the SFM-SDC anode due to the low O2-/CH4 ratio.

  17. Methane production from protozoan endosymbionts following stimulation of microbial metabolism within subsurface sediments.

    PubMed

    Holmes, Dawn E; Giloteaux, Ludovic; Orellana, Roberto; Williams, Kenneth H; Robbins, Mark J; Lovley, Derek R

    2014-01-01

    Previous studies have suggested that protozoa prey on Fe(III)- and sulfate-reducing bacteria that are enriched when acetate is added to uranium contaminated subsurface sediments to stimulate U(VI) reduction. In order to determine whether protozoa continue to impact subsurface biogeochemistry after these acetate amendments have stopped, 18S rRNA and ß-tubulin sequences from this phase of an in situ uranium bioremediation field experiment were analyzed. Sequences most similar to Metopus species predominated, with the majority of sequences most closely related to M. palaeformis, a cilitated protozoan known to harbor methanogenic symbionts. Quantification of mcrA mRNA transcripts in the groundwater suggested that methanogens closely related to Metopus endosymbionts were metabolically active at this time. There was a strong correlation between the number of mcrA transcripts from the putative endosymbiotic methanogen and Metopus ß-tubulin mRNA transcripts during the course of the field experiment, suggesting that the activity of the methanogens was dependent upon the activity of the Metopus species. Addition of the eukaryotic inhibitors cyclohexamide and colchicine to laboratory incubations of acetate-amended subsurface sediments significantly inhibited methane production and there was a direct correlation between methane concentration and Metopus ß-tubulin and putative symbiont mcrA gene copies. These results suggest that, following the stimulation of subsurface microbial growth with acetate, protozoa harboring methanogenic endosymbionts become important members of the microbial community, feeding on moribund biomass and producing methane.

  18. Pressure and Temperature Effects on Growth and Methane Production of the Extreme Thermophile Methanococcus jannaschii

    PubMed Central

    Miller, Jay F.; Shah, Nilesh N.; Nelson, Chad M.; Ludlow, Jan M.; Clark, Douglas S.

    1988-01-01

    The marine archaebacterium Methanococcus jannaschii was studied at high temperatures and hyperbaric pressures of helium to investigate the effect of pressure on the behavior of a deep-sea thermophile. Methanogenesis and growth (as measured by protein production) at both 86 and 90°C were accelerated by pressure up to 750 atm (1 atm = 101.29kPa), but growth was not observed above 90°C at either 7.8 or 250 atm. However, growth and methanogenesis were uncoupled above 90°C, and the high-temperature limit for methanogenesis was increased by pressure. Substantial methane formation was evident at 98°C and 250 atm, whereas no methane formation was observed at 94°C and 7.8 atm. In contrast, when argon was substituted for helium as the pressurizing gas at 250 atm, no methane was produced at 86°C. Methanogenesis was also suppressed at 86°C and 250 atm when the culture was pressurized with a 4:1 mix of H2 and CO2, although limited methanogenesis did occur when the culture was pressurized with H2. PMID:16347794

  19. Coalbed methane resource potential of the Piceance Basin, northwestern Colorado

    SciTech Connect

    Tyler, R.; Scott, A.R.; Kaiser, W.R.

    1996-06-01

    As predicted, from an evolving coalbed methane producibility model, prolific coalbed methane production is precluded in the Piceance Basin by the absence of coal bed reservoir continuity and dynamic ground-water flow. The best potential for production may lie at the transition zone from hydropressure to hydrocarbon overpressure and/or in conventional traps basinward of where outcrop and subsurface coals are in good reservoir and hydraulic communication. Geologic and hydrologic synergy among tectonic and structural setting, depositional systems and coal distribution, coal rank, gas content, permeability and hydrodynamics are the controls that determine the coalbed methane resource potential of the Piceance Basin. Within the coal-bearing Upper Cretaceous Williams Fork Formation, the prime coalbed methane target, reservoir heterogeneity and thrust faults cause coal beds along the Grand Hogback and in the subsurface to be in modest to poor reservoir and hydraulic communication, restricting meteoric ground water recharge and basinward flow. Total subsurface coalbed methane resources are still estimated to be approximately 99 Tcf (3.09 Tm{sup 3}), although coalbed methane resource estimates range between 80 (2.49 Tm{sup 3}) and 136 Tcf (4.24 Tm{sup 3}), depending on the calculation method used. To explore for high gas contents or fully gas-saturated coals and consequent high productivity in the Piceance Basin, improved geologic and completion technologies including exploration and development for migrated conventionally and hydrodynamically trapped gases, in-situ generated secondary biogenic gases, and solution gases will be required.

  20. Influence of Oxygenated Compounds on Reaction Products in a Microwave Plasma Methane Pyrolysis Assembly for Post-Processing of Sabatier Methane

    NASA Technical Reports Server (NTRS)

    Mansell, J. Matthew; Abney, Morgan B.

    2012-01-01

    The state-of-the-art Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS) in April 2010. The system is designed to accept carbon dioxide from the Carbon Dioxide Removal Assembly and hydrogen from the Oxygen Generation Assembly. The two gases are reacted in the CRA in a Sabatier reactor to produce water and methane. Venting of methane results in an oxygen resupply requirement of about 378 lbs per crew member per year. If the oxygen is supplied as water, the total weight for resupply is about 476 lb per crew member per year. For long-term missions beyond low Earth orbit, during which resupply capabilities will be further limited, recovery of hydrogen from methane is highly desirable. For this purpose, NASA is pursuing development of a Plasma Pyrolysis Assembly (PPA) capable of recovering hydrogen from methane. Under certain conditions, water vapor and carbon dioxide (nominally intended to be separated from the CRA outlet stream) may be present in the PPA feed stream. Thus, testing was conducted in 2010 to determine the effect of these oxygenated compounds on PPA performance, particularly the effect of inlet carbon dioxide and water variations on the PPA product stream. This paper discusses the test set-up, analysis, and results of this testing.

  1. Influence of Oxygenated Compounds on Reaction Products in a Microwave Plasma Methane Pyrolysis Assembly for Post-Processing of Sabatier Methane

    NASA Technical Reports Server (NTRS)

    Mansell, J. Matthew; Abney, Morgan B.; Miller, Lee A.

    2011-01-01

    The state-of-the-art Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS) in April 2010. The system is designed to accept carbon dioxide from the Carbon Dioxide Removal Assembly and hydrogen from the Oxygen Generation Assembly. The two gases are reacted in the CRA in a Sabatier reactor to produce water and methane. Venting of methane results in an oxygen resupply requirement of about 378 lbs per crew member per year. If the oxygen is supplied as water, the total weight for resupply is about 476 lb per crew member per year. For long-term missions beyond low Earth orbit, during which resupply capabilities will be further limited, recovery of hydrogen from methane is highly desirable. For this purpose, NASA is pursuing development of a Plasma Pyrolysis Assembly (PPA) capable of recovering hydrogen from methane. Under certain conditions, water vapor and carbon dioxide (nominally intended to be separated from the CRA outlet stream) may be present in the PPA feed stream. Thus, testing was conducted in 2010 to determine the effect of these "oxygenated" compounds on PPA performance, particularly the effect of inlet carbon dioxide and water variations on the PPA product stream. This paper discusses the test set-up, analysis, and results of this testing

  2. The cumulative methane production from dairy cattle slurry can be explained by its volatile solid, temperature and length of storage.

    PubMed

    Sawamoto, Takuji; Nakamura, Megumi; Nekomoto, Kenji; Hoshiba, Shinji; Minato, Keiko; Nakayama, Motoo; Osada, Takashi

    2016-06-01

    In order to refine the national estimate of methane emission from stored cattle slurry, it is important to comprehend the basic characteristics of methane production. Two dairy cattle slurries were obtained from livestock farms located in Hokkaido (a northern island) and Kyushu (a southern island). The slurries were diluted with water into three levels: undiluted, three times diluted, and 10 times diluted. Three hundred mL of the slurries were put into a bottle with a headspace volume of 2.0 L, which was filled with nitrogen gas and then sealed by butyl rubber. Four levels of temperature were used for incubation: 35, 25, 15 and 5 °C. The time course of the cumulative methane production per volatile solid (VS) was satisfactorily expressed by an asymptotic regression model. The effect of dilution on the methane production per VS was not distinctive, but that of temperature was of primary importance. In particular, higher temperature yields a higher potential production and a shorter time when the cumulative production reaches half of the potential production. The inclusive and simple models obtained in this study indicate that the cumulative methane production from stored cattle slurry can be explained by VS, temperature and length of storage.

  3. River methane hot-spots: Continuous methane ebullition measurements over an annual cycle linked to river sediment production

    NASA Astrophysics Data System (ADS)

    Wilkinson, Jeremy; Maeck, Andreas; Ashboul, Zeyad; Lorke, Andreas

    2015-04-01

    Hot spot methane ebullition from impounded river reaches matches high rates observed around the globe. Ebullition dominates total methane flux in the Saar River (Germany) and is largely determined by sediment deposition rate. Using automated bubble traps developed in-house, and deployed over a year at four sites, we collected high resolution data showing that hydrodynamic disturbances from shipping, lock operations and hydrograph events trigger ebullition episodes. Reverse smoothing was used to integrate the observed ebullition back in time, and helped in visualizing the data, and provides a time-series closer to methane accumulation in the sediments, whereas ebullition shows the triggering and release of the accumulated gas. One major hydrological disturbance of shallow-water sediment released around 13% of the total annual ebullition at that site, and ebullition generally followed the seasonal sediment temperature variations. The same event damped ebullition from deeper water sites. Total annual ebullition values ranged from 200 to 500 gCH4 m-2 yr-1. Ebullition from shallow water sediments in winter ceased for extended periods, but continued un-broken from deeper sites. With on-going measurements we believe these findings will help to improve estimates and the modelling of methane emissions from impounded river systems.

  4. Microbial penetration through Berea sandstone and the effect of nitrate on biogenic sulfide production: their relevance to microbial enhanced oil recovery

    SciTech Connect

    Jenneman, G.E.

    1985-01-01

    Penetration times, and penetration rates, for a motile Bacillus strain growing in nutrient-saturated Berea sandstone cores were determined. The rate of penetration was essentially independent of permeability above 100 mD and rapidly declined for permeabilities below 100 mD. The maximum observed penetration rate was 0.47 cm/h and the slowest was 0.06 xm/h. The motile Enterobacter aerrogenes penetrated Berea sandstone cores 3-8 times faster than the non-motile Klebsiella pneumoniae strain when cores of comparable length of permeability were used. Results from energy dispersion spectroscopy, and electron microscopy of autoclaved and dry-heat sterilized rock revealed that changes in mineral content and clay morphology of autoclaved rock could account for faster penetration of bacteria through autoclaved versus dry-heat sterilized rock. However, changes in permeability, porosity, and pore throat size of rock sterilized by the two methods were not sufficient to account for differences in penetration times. The addition of 58.8 mM nitrate was found to inhibit biogenic sulfide production in sewage sludge (10% v/v) amended with 20 mM sulfate and either acetate, glucose, or hydrogen as energy sources. Lesser amounts of nitrate (5.9 mM and 19.5 mM), as well as, increasing amounts of sewage sludge resulted in only transient inhibition of sulfide production. The addition of 156 mM sulfate and 58.8 mM nitrate to 10% sewage sludge or pond sediment slurries resulted in no sulfide inhibition. The prolonged inhibition of sulfide production was attributed to an increase in oxidation-reduction potential due to production of biogenic nitrous oxide. These oxidized conditions appeared to have a cytotoxic affect on sulfate-reducing populations.

  5. Production of hydrogen bromide by bromine-methane reactions at elevated temperature.

    SciTech Connect

    Bradshaw, Robert W.; Larson, Richard S.

    2003-05-01