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Sample records for landfill cover soils

  1. Limits and dynamics of methane oxidation in landfill cover soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to understand the limits and dynamics of methane (CH4) oxidation in landfill cover soils, we investigated CH4 oxidation in daily, intermediate, and final cover soils from two California landfills as a function of temperature, soil moisture and CO2 concentration. The results indicate a signi...

  2. Hydrologic modeling of soil water storage in landfill cover systems

    SciTech Connect

    Barnes, F.J.; Rodgers, J.C.

    1987-01-01

    The accuracy of modeling soil water storage by two hydrologic models, CREAMS and HELP, was tested by comparing simulation results with field measurements of soil moisture in eight experimental landfill cover systems having a range of well-defined soil profiles and vegetative covers. Regression analysis showed that CREAMS generally represented soil moisture more accurately than HELP simulations. Soil profiles that more closely resembled natural agricultural soils were more accurately modeled than highly artificial layered soil profiles. Precautions for determining parameter values for model input and for interpreting simulation results are discussed.

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

    PubMed

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

    2014-05-01

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

  4. Temporal variability of soil gas composition in landfill covers.

    PubMed

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

    2011-05-01

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

  5. Activity and structure of methanotrophic communities in landfill cover soils.

    PubMed

    Gebert, Julia; Singh, Brajesh Kumar; Pan, Yao; Bodrossy, Levente

    2009-10-01

    The composition of the methanotrophic community in soil covers on five landfills in Northern and Eastern Germany was investigated by means of diagnostic microarray and terminal restriction fragment length polymorphism (T-RFLP), both targeting the pmoA gene of methanotrophs. Physical and chemical properties of the 15 sampled soil profiles varied greatly, thus providing for very different environmental conditions. The potential methane oxidation activity, assessed using undisturbed soil cores, varied between 0.2 and 28 µg CH4 gdw (-1)  h(-1) , the latter amounting to 426 g CH4 m(-2)  h(-1) . Total nitrogen was found to be the soil variable correlating most strongly with methanotrophic activity. Explaining close to 50% of the observed variability, this indicates that on the investigated sites activity and thus abundance of methanotrophs may have been nitrogen-limited. Variables that enhance organic matter and thus nitrogen accumulation, such as field capacity, also positively impacted methanotrophic activity. In spite of the great variability of soil properties and different geographic landfill location, both microarray and T-RFLP analysis suggested that the composition of the methanotrophic community on all five sites, in all profiles and across all depths was similar. Methylocystis, Methylobacter and Methylococcus species, including Methylococcus-related uncultivated methanotrophs, were predominantly detected among type II, Ia and Ib methanotrophs, respectively. This indicates that the high methane fluxes typical for landfill environments may be the most influential driver governing the community composition, or other variables not analysed in this study. Principal component analysis suggested that community diversity is most influenced by the site from which the samples were taken and second, from the location on the individual sites, i.e. the soil profile. Landfill and individual profiles reflect the combined impact of all effective variables, including

  6. Microbial mitigation of greenhouse gas emissions from landfill cover soils

    NASA Astrophysics Data System (ADS)

    Lee, Sung-Woo

    Landfills are one of the major sources of methane (CH4), a potent greenhouse gas with a global warming potential (GWP) ˜23 times higher than that of carbon dioxide (CO2). Although some effective strategies have been formulated to prevent methane emissions from large landfills, many landfills allow methane to be freely emitted to the atmosphere. In such situations, it is often proposed to stimulate methanotrophs, a group of bacteria that consume methane, in the cover soil to prevent fugitive methane emissions. Several factors, however, must be addressed to make such a biogenic removal mechanism effective. First, methanotrophic activity can be inhibited by nonmethane organic compounds (NMOCs) that are commonly found in landfill soil gas. Second, although methanotrophs can be easily stimulated with the addition of nitrogenous fertilizers, biogenic production of nitrous oxide with a GWP ˜296 times higher than that of carbon dioxide, is also stimulated. To consider these issues, two general areas of research were performed. First, a dimensionless number was developed based on Michaelis-Menten kinetics that describes the effects of the presence of multiple NMOCs on methanotrophic growth and survival. This model was validated via experimental measurements of methanotrophic growth in the presence of varying amounts of NMOCs. Second, the effects of nutrient amendments on methane oxidation and nitrous oxide production were examined by constructing soil microcosms using landfill cover soils. Here, it was shown that the addition of ammonium in the presence of phenylacetylene stimulated methane oxidation but inhibited nitrous oxide production. Furthermore, to understand the methanotrophic community structure and activity in response to these amendments, DNA microarray and transcript analyses were performed. The results indicated the predominance of Type II methanotrophs but that Type I methanotrophs responded more significantly to these amendments. Also, substantial activity

  7. Rapid Methane Oxidation in a Landfill Cover Soil

    PubMed Central

    Whalen, S. C.; Reeburgh, W. S.; Sandbeck, K. A.

    1990-01-01

    Methane oxidation rates observed in a topsoil covering a retired landfill are the highest reported (45 g m−2 day−1) for any environment. This microbial community had the capacity to rapidly oxidize CH4 at concentrations ranging from <1 ppm (microliters per liter) (first-order rate constant [k] = −0.54 h−1) to >104 ppm (k = −2.37 h−1). The physiological characteristics of a methanotroph isolated from the soil (characteristics determined in aqueous medium) and the natural population, however, were similar to those of other natural populations and cultures: the Q10 and optimum temperature were 1.9 and 31°C, respectively, the apparent half-saturation constant was 2.5 to 9.3 μM, and 19 to 69% of oxidized CH4 was assimilated into biomass. The CH4 oxidation rate of this soil under waterlogged (41% [wt/vol] H2O) conditions, 6.1 mg liter−1 day−1, was near rates reported for lake sediment and much lower than the rate of 116 mg liter−1 day−1 in the same soil under moist (11% H2O) conditions. Since there are no large physiological differences between this microbial community and other CH4 oxidizers, we attribute the high CH4 oxidation rate in moist soil to enhanced CH4 transport to the microorganisms; gas-phase molecular diffusion is 104-fold faster than aqueous diffusion. These high CH4 oxidation rates in moist soil have implications that are important in global climate change. Soil CH4 oxidation could become a negative feedback to atmospheric CH4 increases (and warming) in areas that are presently waterlogged but are projected to undergo a reduction in summer soil moisture. PMID:16348346

  8. Microbial community structures and metabolic profiles response differently to physiochemical properties between three landfill cover soils.

    PubMed

    Long, Xi-En; Wang, Juan; Huang, Ying; Yao, Huaiying

    2016-08-01

    Landfills are always the most important part of solid waste management and bear diverse metabolic activities involved in element biogeochemical cycling. There is an increasing interest in understanding the microbial community and activities in landfill cover soils. To improve our knowledge of landfill ecosystems, we determined the microbial physiological profiles and communities in three landfill cover soils (Ninghai: NH, Xiangshan: XS, and Fenghua: FH) of different ages using the MicroResp(TM), phospholipid fatty acid (PLFA), and high-throughput sequencing techniques. Both total PLFAs and glucose-induced respiration suggested more active microorganisms occurred in intermediate cover soils. Microorganisms in all landfill cover soils favored L-malic acid, ketoglutarate, and citric acid. Gram-negative bacterial PLFAs predominated in all samples with the representation of 16:1ω7, 18:1ω7, and cy19:0 in XS and NH sites. Proteobacteria dominated soil microbial phyla across different sites, soil layers, and season samples. Canonical correspondence analysis showed soil pH, dissolved organic C (DOC), As, and total nitrogen (TN) contents significantly influenced the microbial community but TN affected the microbial physiological activities in both summer and winter landfill cover soils. PMID:27117156

  9. Gas Transport Parameters for Landfill Cover Soils: Effects of Soil Compaction and Water Blockages

    NASA Astrophysics Data System (ADS)

    Wickramarachchi, P. N.; Hamamoto, S.; Kawamoto, K.; Nawagamuwa, U.; Komatsu, T.; Moldrup, P.

    2009-12-01

    Recently, landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric CH4. landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest source of anthropogenic CH4 emission , the final cover system should also be designed for minimizing the biogas migration into the atmosphere or the areas surrounding the landfill. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil , there are few studies about gas transport characteristics of landfill cover soils. Therefore, the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size and water blockage effects on the gas exchange in t highly compacted final cover soil are largely unknown. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport . In this study, the effects of compaction level and water blockage effects on ka and Dp for two landfill final cover soils were investigated. The disturbed soil samples were taken from landfill final covers in Japan and Sri Lanka. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm) at two different compaction levels (2700 kN/m2 and 600 kN/m2). After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential (pF; pF equals to log(-ɛ) where ɛ is soil-water matric potential in cm H2O) of 1.5, 2.0, 3.0, 4.1, and with air-dried (pF 6.0) and oven-dried (pF 6.9) conditions. Results showed that measured Dp values

  10. Mechanism of H2S removal during landfill stabilization in waste biocover soil, an alterative landfill cover.

    PubMed

    He, Ruo; Xia, Fang-Fang; Bai, Yun; Wang, Jing; Shen, Dong-Sheng

    2012-05-30

    Hydrogen sulfide (H(2)S) is one of the primary contributors to odors at landfills. The mechanism of waste biocover soil (WBS) for H(2)S removal was investigated in simulated landfill systems with the contrast experiment of a landfill cover soil (LCS). The H(2)S removal efficiency was higher than 90% regardless of the WBS or LCS covers. The input of landfill gas (LFG) could stimulate the growth of aerobic heterotrophic bacteria, actinomycete, sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) in the WBS cover, while that caused a decrease of 1-2 orders of magnitude in the populations of actinomycete and fungi in the bottom layer of the LCS cover. As H(2)S inputted, the sulfide content in the WBS cover increased and reached the maximum on day 30. In the LCS cover, the highest soil sulfide content was exhibited in the bottom layer during the whole experiment. After exposure to LFG, the lower pH value and higher sulfate content were observed in the top layer of the WBS cover, while there was not a significant difference in different layers of the LCS cover. The results indicated a more rapid biotransformation between sulfide and sulfate occurred in the WBS cover compared to the LCS. PMID:22459970

  11. Comparison of Methods to Assess the Fate of Methane in a Landfill-Cover Soil

    NASA Astrophysics Data System (ADS)

    Gomez, K. E.; Schroth, M. H.; Eugster, W.; Niklaus, P.; Oester, P.; Zeyer, J.

    2008-12-01

    A substantial fraction of the greenhouse gas methane released into the atmosphere is produced in terrestrial environments such as wetlands, rice paddy fields, and landfills. However, the amount of methane that is emitted from these environments is often reduced by microbial methane oxidation, mediated by methanotrophic microorganisms. Methanotrophs are ubiquitous in soils and represent the largest biological sink for methane. We performed a series of field experiments in summer 2008 to compare several state-of- the-art methods to assess the fate of methane in a landfill-cover soil near Liestal (BL), Switzerland. Methods employed included eddy-covariance and field-chamber measurements to quantify net methane flux at the landfill surface. In addition, methane concentrations at the landfill surface were monitored using a portable methane detector. Methane fluxes within the cover soil were estimated from methane-concentration profiles in conjunction with radon measurements. Additionally, gas push-pull tests were employed for in-situ quantification of methane oxidation in the cover soil. Finally, methane stable-carbon-isotope measurements were conducted to corroborate methane oxidation in the cover soil. Preliminary results indicate that each method provides unique information, and when combined, the data provide detailed insight in the fate of methane in the cover soil. The investigated landfill-cover soil appears to be ordinarily a net sink for methane. However, it can quickly turn into a net source of methane under adverse meteorological conditions.

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

    NASA Astrophysics Data System (ADS)

    Zhang, Houhu; He, Pinjing; Shao, Liming

    CH 4 emissions and leachate disposal are recognized as the two major concerns in municipal solid waste (MSW) landfills. Recently, leachate recirculation was attempted to accelerate land-filled waste biodegradation and thus enhanced landfill gas generation. Leachate irrigation was also conducted for volume reduction effectively. Nevertheless, the impacts of leachate recirculation and irrigation on landfill CH 4 emissions have not been previously reported. A field investigation of landfill CH 4 emissions was conducted on selected sandy soil cover with leachate recirculation and subsurface irrigation based on whole year around measurement. The average CH 4 fluxes were 311±903, 207±516, and 565±1460 CH 4 m -2 h -1 from site A without leachate recirculation and subsurface irrigation, lift B2 with leachate subsurface irrigation, and lift B1 with both leachate recirculation and subsurface irrigation, respectively. Both gas recovery and cover soil oxidation minimized CH 4 emissions efficiently, while the later might be more pronounced when the location was more than 5 m away from gas recovery well. After covered by additional clay soil layer, CH 4 fluxes dropped by approximately 35 times in the following three seasons compared to the previous three seasons in lift B2. The diurnal peaks of CH 4 fluxes occurred mostly followed with air or soil temperature in the daytimes. The measured CH 4 fluxes were much lower than those of documented data from the landfills, indicating that the influences of leachate recirculation and subsurface irrigation on landfill CH 4 emissions might be minimized with the help of a well-designed sandy soil cover. Landfill cover composed of two soil layers (clay soil underneath and sandy soil above) is suggested as a low-cost and effective alternative to minimize CH 4 emissions.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  14. Characterization of H2S removal and microbial community in landfill cover soils.

    PubMed

    Xia, Fang-Fang; Zhang, Hong-Tao; Wei, Xiao-Meng; Su, Yao; He, Ruo

    2015-12-01

    H2S is a source of odors at landfills and poses a threat to the surrounding environment and public health. In this work, compared with a usual landfill cover soil (LCS), H2S removal and biotransformation were characterized in waste biocover soil (WBS), an alternative landfill cover material. With the input of landfill gas (LFG), the gas concentrations of CH4, CO2, O2, and H2S, microbial community and activity in landfill covers changed with time. Compared with LCS, lower CH4 and H2S concentrations were detected in the WBS. The potential sulfur-oxidizing rate and sulfate-reducing rate as well as the contents of acid-volatile sulfide, SO4(2-), and total sulfur in the WBS and LCS were all increased with the input of LFG. After exposure to LFG for 35 days, the sulfur-oxidizing rate of the bottom layer of the WBS reached 82.5 μmol g dry weight (d.w.)(-1) day(-1), which was 4.3-5.4 times of that of LCS. H2S-S was mainly deposited in the soil covers, while it escaped from landfills to the atmosphere. The adsorption, absorption, and biotransformation of H2S could lead to the decrease in the pH values of landfill covers; especially, in the LCS with low pH buffer capacity, the pH value of the bottom layer dropped to below 4. Pyrosequencing of 16S ribosomal RNA (rRNA) gene showed that the known sulfur-metabolizing bacteria Ochrobactrum, Paracoccus, Comamonas, Pseudomonas, and Acinetobacter dominated in the WBS and LCS. Among them, Comamonas and Acinetobacter might play an important role in the metabolism of H2S in the WBS. These findings are helpful to understand sulfur bioconversion process in landfill covers and to develop techniques for controlling odor pollution at landfills. PMID:26206130

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

    PubMed

    Hossain, Md Sahadat; Haque, Mohamed A

    2009-05-01

    Bioreactor landfills are operated to enhance refuse decomposition, gas production, and waste stabilization. The major aspect of bioreactor landfill operation is the recirculation of collected leachate back through the refuse mass. Due to the accelerated decomposition and settlement of solid waste, bioreactor landfills are gaining popularity as an alternative to the conventional landfill. The addition or recirculation of leachate to accelerate the waste decomposition changes the geotechnical characteristics of waste mass. The daily cover soils, usually up to 20-30% of total MSW volumes in the landfill, may also influence the decomposition and shear strength behavior of MSW. The objective of this paper is to study the effects of daily covers soils on the shear strength properties of municipal solid waste (MSW) in bioreactor landfills with time and decomposition. Two sets of laboratory-scale bioreactor landfills were simulated in a laboratory, and samples were prepared to represent different phases of decomposition. The state of decomposition was quantified by methane yield, pH, and volatile organic content (VOC). Due to decomposition, the matrix structure of the degradable solid waste component was broken down and contributed to a significant decrease in the reinforcing effect of MSW. However, the daily cover soil, a non-degradable constituent of MSW, remains constant. Therefore, the interaction between daily cover soil particles and MSW particles will affect shear strength behavior. A number of triaxial tests were performed to evaluate the shear strength of MSW. The test results indicated that the shear strength of MSW was affected by the presence of cover soils. The friction angle of MSW with the presence of cover soil is higher than the friction angle of MSW without any cover soils. The friction angle of MSW increased from 27 degrees to 30 degrees due to the presence of cover soils for Phase 1 samples. The increased strength was attributed to the friction nature

  16. Effects of biochar amendment on geotechnical properties of landfill cover soil.

    PubMed

    Reddy, Krishna R; Yaghoubi, Poupak; Yukselen-Aksoy, Yeliz

    2015-06-01

    Biochar is a carbon-rich product obtained when plant-based biomass is heated in a closed container with little or no available oxygen. Biochar-amended soil has the potential to serve as a landfill cover material that can oxidise methane emissions for two reasons: biochar amendment can increase the methane retention time and also enhance the biological activity that can promote the methanotrophic oxidation of methane. Hydraulic conductivity, compressibility and shear strength are the most important geotechnical properties that are required for the design of effective and stable landfill cover systems, but no studies have been reported on these properties for biochar-amended landfill cover soils. This article presents physicochemical and geotechnical properties of a biochar, a landfill cover soil and biochar-amended soils. Specifically, the effects of amending 5%, 10% and 20% biochar (of different particle sizes as produced, size-20 and size-40) to soil on its physicochemical properties, such as moisture content, organic content, specific gravity and pH, as well as geotechnical properties, such as hydraulic conductivity, compressibility and shear strength, were determined from laboratory testing. Soil or biochar samples were prepared by mixing them with 20% deionised water based on dry weight. Samples of soil amended with 5%, 10% and 20% biochar (w/w) as-is or of different select sizes, were also prepared at 20% initial moisture content. The results show that the hydraulic conductivity of the soil increases, compressibility of the soil decreases and shear strength of the soil increases with an increase in the biochar amendment, and with a decrease in biochar particle size. Overall, the study revealed that biochar-amended soils can possess excellent geotechnical properties to serve as stable landfill cover materials. PMID:25898984

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

    PubMed

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

    2008-01-01

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

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

    PubMed

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

    2011-05-01

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

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

    SciTech Connect

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

    2011-05-15

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

  20. Above- and below-ground methane fluxes and methanotrophic activity in a landfill-cover soil.

    PubMed

    Schroth, M H; Eugster, W; Gómez, K E; Gonzalez-Gil, G; Niklaus, P A; Oester, P

    2012-05-01

    Landfills are a major anthropogenic source of the greenhouse gas methane (CH(4)). However, much of the CH(4) produced during the anaerobic degradation of organic waste is consumed by methanotrophic microorganisms during passage through the landfill-cover soil. On a section of a closed landfill near Liestal, Switzerland, we performed experiments to compare CH(4) fluxes obtained by different methods at or above the cover-soil surface with below-ground fluxes, and to link methanotrophic activity to estimates of CH(4) ingress (loading) from the waste body at selected locations. Fluxes of CH(4) into or out of the cover soil were quantified by eddy-covariance and static flux-chamber measurements. In addition, CH(4) concentrations at the soil surface were monitored using a field-portable FID detector. Near-surface CH(4) fluxes and CH(4) loading were estimated from soil-gas concentration profiles in conjunction with radon measurements, and gas push-pull tests (GPPTs) were performed to quantify rates of microbial CH(4) oxidation. Eddy-covariance measurements yielded by far the largest and probably most representative estimates of overall CH(4) emissions from the test section (daily mean up to ∼91,500μmolm(-2)d(-1)), whereas flux-chamber measurements and CH(4) concentration profiles indicated that at the majority of locations the cover soil was a net sink for atmospheric CH(4) (uptake up to -380μmolm(-2)d(-1)) during the experimental period. Methane concentration profiles also indicated strong variability in CH(4) loading over short distances in the cover soil, while potential methanotrophic activity derived from GPPTs was high (v(max)∼13mmolL(-1)(soil air)h(-1)) at a location with substantial CH(4) loading. Our results provide a basis to assess spatial and temporal variability of CH(4) dynamics in the complex terrain of a landfill-cover soil. PMID:22143049

  1. Utilisation of chemically stabilized arsenic-contaminated soil in a landfill cover.

    PubMed

    Kumpiene, Jurate; Desogus, Paolo; Schulenburg, Sven; Arenella, Mariarita; Renella, Giancarlo; Brännvall, Evelina; Lagerkvist, Anders; Andreas, Lale; Sjöblom, Rolf

    2013-12-01

    The aim of the study was to determine if an As-contaminated soil, stabilized using zerovalent iron (Fe(0)) and its combination with gypsum waste, coal fly ash, peat, or sewage sludge, could be used as a construction material at the top layer of the landfill cover. A reproduction of 2 m thick protection/vegetation layer of a landfill cover using a column setup was used to determine the ability of the amendments to reduce As solubility and stimulate soil functionality along the soil profile. Soil amendment with Fe(0) was highly efficient in reducing As in soil porewater reaching 99 % reduction, but only at the soil surface. In the deeper soil layers (below 0.5 m), the Fe treatment had a reverse effect, As solubility increased dramatically exceeding that of the untreated soil or any other treatment by one to two orders of magnitude. A slight bioluminescence inhibition of Vibrio fischeri was detected in the Fe(0) treatment. Soil amendment with iron and peat showed no toxicity to bacteria and was the most efficient in reducing dissolved As in soil porewater throughout the 2 m soil profile followed by iron and gypsum treatment, most likely resulting from a low soil density and a good air diffusion to the soil. The least suitable combination of soil amendments for As immobilization was a mixture of iron with coal fly ash. An increase in all measured enzyme activities was observed in all treatments, particularly those receiving organic matter. For As to be stable in soil, a combination of amendments that can keep the soil porous and ensure the air diffusion through the entire soil layer of the landfill cover is required. PMID:23709267

  2. Responses of oxidation rate and microbial communities to methane in simulated landfill cover soil microcosms.

    PubMed

    He, Ruo; Ruan, Aidong; Jiang, Chenjing; Shen, Dong-Sheng

    2008-10-01

    CH4 oxidation capacities and microbial community structures developed in response to the presence of CH4 were investigated in two types of landfill cover soil microcosms, waste soil (fine material in stabilized waste) and clay soil. CH4 emission fluxes were lower in the waste soil cover over the course of the experiment. After exposure to CH4 flow for 120 days, the waste soil developed CH4 oxidation capacity from 0.53 to 11.25-13.48micromol CH4gd.w.(-1)h(-1), which was ten times higher than the clay soil. The topsoils of the two soil covers were observed dried and inhibited CH4 oxidation. The maximum CH4 oxidation rate occurred at the depth of 10-20cm in the waste soil cover (the middle layer), whereas it took place mainly at the depth of 20-30cm in the clay soil cover (the bottom layer). The amounts of the phospholipid fatty acid (PLFA) biomarks 16:1omega8c and 18:1omega8c for type I and II methanotrophs, respectively, showed that type I methanotrophic bacteria predominated in the clay soil, while the type II methanotrophic bacteria were abundant in the waste soil, and the highest population in the middle layer. The results also indicated that a greater active methanotrophic community was developed in the waste soil relative to the clay soil. PMID:18294841

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

    SciTech Connect

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

    2010-09-30

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

  4. Adsorption and transport of methane in landfill cover soil amended with waste-wood biochars.

    PubMed

    Sadasivam, Bala Yamini; Reddy, Krishna R

    2015-08-01

    The natural presence of methane oxidizing bacteria (MOB) in landfill soils can stimulate the bio-chemical oxidation of CH4 to CO2 and H2O under suitable environmental conditions. This mechanism can be enhanced by amending the landfill cover soil with organic materials such as biochars that are recalcitrant to biological degradation and are capable of adsorbing CH4 while facilitating the growth and activity of MOB within their porous structure. Several series of batch and small-scale column tests were conducted to quantify the CH4 sorption and transport properties of landfill cover soil amended with four types of waste hardwood biochars under different levels of amendment percentages (2, 5 and 10% by weight), exposed CH4 concentrations (0-1 kPa), moisture content (dry, 25% and 75% water holding capacity), and temperature (25, 35 and 45 °C). The linear forms of the pseudo second-order kinetic model and the Langmuir isotherm model were used to determine the kinetics and the maximum CH4 adsorption capacity of cover materials. The maximum CH4 sorption capacity of dry biochar-amended soils ranged from 1.03 × 10(-2) to 7.97 × 10(-2) mol kg(-1) and exhibited a ten-fold increase compared to that of soil with 1.9 × 10(-3) mol kg(-1). The isosteric heat of adsorption for soil was negative and ranged from -30 to -118 kJ/mol, while that of the biochar-amended soils was positive and ranged from 24 to 440 kJ/mol. The CH4 dispersion coefficients for biochar-amended soils obtained through predictive transport modeling indicated that amending the soil with biochar enhanced the methane transport rates by two orders of magnitude, thereby increasing their potential for enhanced exchange of gases within the cover system. Overall, the use of hardwood biochars as a cover soil amendment to reduce methane emissions from landfills appears to be a promising alternative to conventional soil covers. PMID:25935750

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

    PubMed

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

    2011-05-01

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

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

    PubMed

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

    2011-05-01

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

  7. Performance evaluation of intermediate cover soil barrier for removal of heavy metals in landfill leachate.

    PubMed

    Suzuki, Kazuyuki; Anegawa, Aya; Endo, Kazuto; Yamada, Masato; Ono, Yusaku; Ono, Yoshiro

    2008-11-01

    This pilot-scale study evaluated the use of intermediate cover soil barriers for removing heavy metals in leachate generated from test cells for co-disposed fly ash from municipal solid waste incinerators, ash melting plants, and shredder residue. Cover soil barriers were mixtures of Andisol (volcanic ash soil), waste iron powder, (grinder dust waste from iron foundries), and slag fragments. The cover soil barriers were installed in the test cells' bottom layer. Sorption/desorption is an important process in cover soil bottom barrier for removal of heavy metals in landfill leachate. Salt concentrations such as those of Na, K, and Ca in leachate were extremely high (often greater than 30 gL(-1)) because of high salt content in fly ash from ash melting plants. Concentrations of all heavy metals (nickel, manganese, copper, zinc, lead, and cadmium) in test cell leachates with a cover soil barrier were lower than those of the test cell without a cover soil barrier and were mostly below the discharge limit, probably because of dilution caused by the amount of leachate and heavy metal removal by the cover soil barrier. The cover soil barriers' heavy metal removal efficiency was calculated. About 50% of copper, nickel, and manganese were removed. About 20% of the zinc and boron were removed, but lead and cadmium were removed only slightly. Based on results of calculation of the Langelier saturation index and analyses of core samples, the reactivity of the cover soil barrier apparently decreases because of calcium carbonate precipitation on the cover soil barriers' surfaces. PMID:18842283

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

    PubMed

    Scheutz, Charlotte; Mosbaek, Hans; Kjeldsen, Peter

    2004-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Zhang, Houhu; He, Pinjing; Shao, Liming

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

  10. Estimation of mass transport parameters of gases for quantifying CH4 oxidation in landfill soil covers.

    PubMed

    Im, J; Moon, S; Nam, K; Kim, Y-J; Kim, J Y

    2009-02-01

    Methane (CH(4)), which is one of the most abundant anthropogenic greenhouse gases, is produced from landfills. CH(4) is biologically oxidized to carbon dioxide, which has a lower global warming potential than methane, when it passes through a cover soil. In order to quantify the amount of CH(4) oxidized in a landfill cover soil, a soil column test, a diffusion cell test, and a mathematical model analysis were carried out. In the column test, maximum oxidation rates of CH(4) (V(max)) showed higher values in the upper part of the column than those in the lower part caused by the penetration of O(2) from the top. The organic matter content in the upper area was also higher due to the active microbial growth. The dispersion analysis results for O(2) and CH(4) in the column are counter-intuitive. As the upward flow rate of the landfill gas increased, the dispersion coefficient of CH(4) slightly increased, possibly due to the effect of mechanical dispersion. On the other hand, as the upward flow rate of the landfill gas increased, the dispersion coefficient of O(2) decreased. It is possible that the diffusion of gases in porous media is influenced by the counter-directional flow rate. Further analysis of other gases in the column, N(2) and CO(2), may be required to support this hypothesis, but in this paper we propose the possibility that the simulations using the diffusion coefficient of O(2) under the natural condition may overestimate the penetration of O(2) into the soil cover layer and consequently overestimate the oxidation of CH(4). PMID:18804363

  11. An analytical model for estimating the reduction of methane emission through landfill cover soils by methane oxidation.

    PubMed

    Yao, Yijun; Su, Yao; Wu, Yun; Liu, Weiping; He, Ruo

    2015-01-01

    Landfill is an important source of atmospheric methane (CH4). In this study, the development and partial validation are presented for an analytical model for predicting the reduction of CH4 emission in landfill cover soils by CH4 oxidation. The model combines an analytic solution of a coupled oxygen (O2) and CH4 soil gas transport in landfill covers with a piecewise first-order aerobic biodegradation, including the influences of environmental factors such as cover soil thickness, CH4 oxidation and CH4 production rate. Comparison of soil gas concentration profiles with a soil column experiment is provided for a partial validation, and then this model is applied to predict the reduction of CH4 emission through landfill covers in several other cases. A discussion is provided to illustrate the roles of soil layer thickness, reaction rate constant for CH4 oxidation and CH4 production rate in determining CH4 emissions. The results suggest that the increase of cover soil thickness cannot always increase CH4 oxidation rates or removal efficiency, which becomes constant if the thickness of landfill cover soil is larger than a limit. PMID:25464331

  12. Above- and below-ground methane fluxes and methanotrophic activity in a landfill-cover soil

    SciTech Connect

    Schroth, M.H.; Eugster, W.; Gomez, K.E.; Gonzalez-Gil, G.; Niklaus, P.A.; Oester, P.

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer We quantify above- and below-ground CH{sub 4} fluxes in a landfill-cover soil. Black-Right-Pointing-Pointer We link methanotrophic activity to estimates of CH{sub 4} loading from the waste body. Black-Right-Pointing-Pointer Methane loading and emissions are highly variable in space and time. Black-Right-Pointing-Pointer Eddy covariance measurements yield largest estimates of CH{sub 4} emissions. Black-Right-Pointing-Pointer Potential methanotrophic activity is high at a location with substantial CH{sub 4} loading. - Abstract: Landfills are a major anthropogenic source of the greenhouse gas methane (CH{sub 4}). However, much of the CH{sub 4} produced during the anaerobic degradation of organic waste is consumed by methanotrophic microorganisms during passage through the landfill-cover soil. On a section of a closed landfill near Liestal, Switzerland, we performed experiments to compare CH{sub 4} fluxes obtained by different methods at or above the cover-soil surface with below-ground fluxes, and to link methanotrophic activity to estimates of CH{sub 4} ingress (loading) from the waste body at selected locations. Fluxes of CH{sub 4} into or out of the cover soil were quantified by eddy-covariance and static flux-chamber measurements. In addition, CH{sub 4} concentrations at the soil surface were monitored using a field-portable FID detector. Near-surface CH{sub 4} fluxes and CH{sub 4} loading were estimated from soil-gas concentration profiles in conjunction with radon measurements, and gas push-pull tests (GPPTs) were performed to quantify rates of microbial CH{sub 4} oxidation. Eddy-covariance measurements yielded by far the largest and probably most representative estimates of overall CH{sub 4} emissions from the test section (daily mean up to {approx}91,500 {mu}mol m{sup -2} d{sup -1}), whereas flux-chamber measurements and CH{sub 4} concentration profiles indicated that at the majority of locations the cover soil was a

  13. Spatial patterns of methane oxidation and methanotrophic diversity in landfill cover soils of southern China.

    PubMed

    Chi, Zi-Fang; Lu, Wen-Jing; Wang, Hong-Tao

    2015-04-01

    Aerobic CH4 oxidation is an important CH4 sink in landfills. To investigate the distribution and community diversity of methanotrophs and link with soil characteristics and operational parameters (e.g., concentrations of O2, CH4), cover soil samples were collected at different locations and depths from the Mengzi semi-aerobic landfill (SAL) in Yunnan Province of southern China. Specific PCR followed by denaturing gradient gel electrophoresis and realtime PCR were used to examine methanotrophs in the landfill cover soils. The results showed that different locations did harbor distinct methanotroph communities. Methanotrophs were more abundant in areas near the venting pipes because of the higher O2 concentrations. The depth of 20-25 cm, where the ratio of the CH4 to O2 was within the range from 1.3 to 8.6, was more conducive to the growth of CH4-oxidizing bacteria. Type II methanotrophs dominated in all samples compared with Type I methanotrophs, as evidenced by the high ratio of Type II to Type I methanotrophic copy numbers (from 1.76 to 11.60). The total copy numbers of methanotrophs detected were similar to other ecosystems, although the CH4 concentration was much higher in SAL cover soil. Methylobacter and Methylocystis were the most abundant Type I and Type II methanotrophs genera, respectively, in the Mengzi SAL. The results suggested that SALs could provide a special environment with both high concentrations of CH4 and O2 for methanotrophs, especially around the vertical venting pipes. PMID:25341468

  14. ENGINEERING BULLETIN: LANDFILL COVERS

    EPA Science Inventory

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

  15. Spatial Variability of Soil Properties and Their Effect on Methane Generation, Oxidation, and Emission from Soils Covering Landfills

    NASA Astrophysics Data System (ADS)

    Imhoff, P. T.; Mei, C.; Yazdani, R.; Han, B.; Mostafid, M.

    2013-12-01

    Soils covering landfills mitigate gas emissions from degrading refuse, particularly emissions of methane, a potent greenhouse gas. To enhance the oxidative capacity of these soils, materials with high organic matter are proposed for landfill covers, e.g., compost and aged greenwaste. We report field tests of these materials in pilot-scale test cells. While moisture conditions and gas transport were initially uniform, after one year significant spatial variability of gas flow developed that was associated with spatially variable dry bulk density and volumetric water content. For a test cell with organic matter content of 38%, a single-domain porous medium model was adequate for describing water retention and continuum modeling was capable of describing spatially variable gas flow and methane oxidation. A second test cell with organic matter of 61% was best described as a dual-domain porous medium, and continuum modeling was inadequate for describing spatially variable gas flow. Here, the dual-domain medium resulted in significant subgrid scale variability in moisture conditions that affected gas transport and methane oxidation. The results from these field tests suggest that proposed one-dimensional models of gas transport and methane oxidation in landfill cover soils may be inadequate for soils composed of high organic matter that require dual-domain models for water retention.

  16. Degradation of C2-C15 volatile organic compounds in a landfill cover soil.

    PubMed

    Tassi, Franco; Montegrossi, Giordano; Vaselli, Orlando; Liccioli, Caterina; Moretti, Sandro; Nisi, Barbara

    2009-07-15

    The composition of non-methane volatile organic compounds (hereafter VOCs) in i) the cover soil, at depths of 30, 50 and 70 cm, and ii) gas recovery wells from Case Passerini landfill site, (Florence, Italy) was determined by GC-MS. The study, based on the analysis of interstitial gases sampled along vertical profiles within the cover soil, was aimed to investigate the VOC behaviour as biogas transits from a reducing to a relatively more oxidizing environment. A total of 48 and 63 different VOCs were identified in the soil and well gases, respectively. Aromatics represent the dominant group (71.5% of total VOC) in soil gases, followed by alkanes (6.8%), ketones (5.7%), organic acids (5.2%), aldehydes (3.0%), esters (2.6%), halogenated compounds (2.1%) and terpenes (1.3%). Cyclics, heterocyclics, S-bearing compounds and phenols are cover soil shows significant variations: alkanes, aromatics and cyclics decrease at decreasing depth, whereas an inverse trend is displayed by the O-bearing species. Total VOC and CH(4) concentrations at a depth of 30 cm in the soil are comparable, inferring that microbial activity is likely affecting VOCs at a very minor extent with respect to CH(4). According to these considerations, to assess the biogas emission impact, usually carried out on the sole basis of CO(2) and CH(4) emission rates, the physical-chemical behaviour of VOCs in the cover soil, regulating the discharge of these highly contaminant compounds in ambient air, has to be taken into account. The soil vertical distribution of these species can be used to better evaluate the efficiency of oxidative capability of intermediate and final covers. PMID:19446310

  17. Modelling of stable isotope fractionation by methane oxidation and diffusion in landfill cover soils

    SciTech Connect

    Mahieu, Koenraad De Visscher, Alex; Vanrolleghem, Peter A.; Van Cleemput, Oswald

    2008-07-01

    A technique to measure biological methane oxidation in landfill cover soils that is gaining increased interest is the measurement of stable isotope fractionation in the methane. Usually to quantify methane oxidation, only fractionation by oxidation is taken into account. Recently it was shown that neglecting the isotope fractionation by diffusion results in underestimation of the methane oxidation. In this study a simulation model was developed that describes gas transport and methane oxidation in landfill cover soils. The model distinguishes between {sup 12}CH{sub 4}, {sup 13}CH{sub 4}, and {sup 12}CH{sub 3}D explicitly, and includes isotope fractionation by diffusion and oxidation. To evaluate the model, the simulations were compared with column experiments from previous studies. The predicted concentration profiles and isotopic profiles match the measured ones very well, with a root mean square deviation (RMSD) of 1.7 vol% in the concentration and a RMSD of 0.8 per mille in the {delta}{sup 13}C value, with {delta}{sup 13}C the relative {sup 13}C abundance as compared to an international standard. Overall, the comparison shows that a model-based isotope approach for the determination of methane oxidation efficiencies is feasible and superior to existing isotope methods.

  18. In-Situ Quantification of Methanotrophic Activity in a Landfill Cover Soil Using Gas Push-Pull Tests

    NASA Astrophysics Data System (ADS)

    Gomez, K. E.; Gonzalez-Gil, G.; Schroth, M. H.; Zeyer, J.

    2007-12-01

    Landfills are both a major anthropogenic source and a sink for the greenhouse gas CH4. Methanogenic bacteria produce CH4 during the anaerobic digestion of landfill waste, whereas, methanotrophic bacteria consume CH4 as it is transported through a landfill cover soil. Methanotrophs are thought to be ubiquitous in soils, but typically exist in large numbers at oxic/anoxic interfaces, close to anaerobic methane sources but exposed to oxygen required for metabolism. Accurate in-situ quantification of the sink strength of methanotrophs in landfill cover soils is needed for global carbon balances and for local emissions mitigation strategies. We measured in-situ CH4 concentrations at 30, 60, and 100 cm depth at 18 evenly spaced locations across a landfill cover soil. Furthermore, we performed Gas Push-Pull Tests (GPPTs) to estimate in-situ rates of methanotrophic activity in the cover soil. The GPPT is a gas-tracer test in which a gas mixture containing CH4, O2, and non-reactive tracer gases is injected (pushed) into the soil followed by extraction (pull) from the same location. Quantification of CH4 oxidation rates is based upon comparison of the breakthrough curves of CH4 and tracer gases. We present the results of a series of GPPTs conducted at two locations in the cover soil to assess the feasibility and reproducibility of this technique to quantify methanotrophic activity. Additional GPPTs were performed with a methanotrophic inhibitor in the injection gas mixture to confirm the appropriate choice of tracers to quantify CH4 oxidation. Estimated CH4 oxidation rate constants indicate that the cover soil contains a highly active methanotrophic community.

  19. Methane oxidation in landfill cover soils, is a 10% default value reasonable?

    PubMed

    Chanton, Jeffrey P; Powelson, David K; Green, Roger B

    2009-01-01

    We reviewed literature results from 42 determinations of the fraction of methane oxidized and 30 determinations of methane oxidation rate in a variety of soil types and landfill covers. Both column measurements and in situ field measurements were included. The means for the fraction of methane oxidized on transit across the soil covers ranged from 22 to 55% from clayey to sandy material. Mean values for oxidation rate ranged from 3.7 to 6.4 mol m(-2) d(-1) (52-102 g m(-2) d(-1)) for the different soil types. The overall mean fraction oxidized across all studies was 36% with a standard error of 6%. The overall mean oxidation rate across all studies was 4.5 mol m(-2) d(-1) +/- 1.0 (72 +/- 16 g m(-2)d(-1)). For the subset of 15 studies conducted over an annual cycle the fraction of methane oxidized ranged from 11 to 89% with a mean value of 35 +/- 6%, nearly identical to the overall mean. Nine of these studies were conducted in north Florida at 30 degrees N latitude and had a fraction oxidized of 27 +/- 4%. Five studies were conducted in northern Europe ( approximately 50-55 degrees N) and exhibited an average of 54 +/- 14%. One study, conducted in New Hampshire, had a value of 10%. The results indicate that the fraction of methane oxidized in landfill greater than the default value of 10%. Of the 42 determinations of methane oxidation reported, only four report values of 10% or less. PMID:19244486

  20. CH4/CO2 ratios indicate highly efficient methane oxidation by a pumice landfill cover-soil.

    PubMed

    Pratt, Chris; Walcroft, Adrian S; Deslippe, Julie; Tate, Kevin R

    2013-02-01

    Landfills that generate too little biogas for economic energy recovery can potentially offset methane (CH(4)) emissions through biological oxidation by methanotrophic bacteria in cover soils. This study reports on the CH(4) oxidation efficiency of a 10-year old landfill cap comprising a volcanic pumice soil. Surface CH(4) and CO(2) fluxes were measured using field chambers during three sampling intervals over winter and summer. Methane fluxes were temporally and spatially variable (-0.36 to 3044 mgCH(4)m(-2)h(-1)); but were at least 15 times lower than typical literature CH(4) fluxes reported for older landfills in 45 of the 46 chambers tested. Exposure of soil from this landfill cover to variable CH(4) fluxes in laboratory microcosms revealed a very strong correlation between CH(4) oxidation efficiency and CH(4)/CO(2) ratios, confirming the utility of this relationship for approximating CH(4) oxidation efficiency. CH(4)/CO(2) ratios were applied to gas concentrations from the surface flux chambers and indicated a mean CH(4) oxidation efficiency of 72%. To examine CH(4) oxidation with soil depth, we collected 10 soil depth profiles at random locations across the landfill. Seven profiles exhibited CH(4) removal rates of 70-100% at depths <60 cm, supporting the high oxidation rates observed in the chambers. Based on a conservative 70% CH(4) oxidation efficiency occurring at the site, this cover soil is clearly offsetting far greater CH(4) quantities than the 10% default value currently adopted by the IPCC. PMID:23186636

  1. Atmospheric emissions and attenuation of non-methane organic compounds in cover soils at a French landfill.

    PubMed

    Scheutz, C; Bogner, J; Chanton, J P; Blake, D; Morcet, M; Aran, C; Kjeldsen, P

    2008-01-01

    In addition to methane (CH(4)) and carbon dioxide (CO(2)), landfill gas may contain more than 200 non-methane organic compounds (NMOCs) including C(2+)-alkanes, aromatics, and halogenated hydrocarbons. Although the trace components make up less than 1% v/v of typical landfill gas, they may exert a disproportionate environmental burden. The objective of this work was to study the dynamics of CH(4) and NMOCs in the landfill cover soils overlying two types of gas collection systems: a conventional gas collection system with vertical wells and an innovative horizontal gas collection layer consisting of permeable gravel with a geomembrane above it. The 47 NMOCs quantified in the landfill gas samples included primarily alkanes (C(2)-C(10)), alkenes (C(2)-C(4)), halogenated hydrocarbons (including (hydro)chlorofluorocarbons ((H)CFCs)), and aromatic hydrocarbons (BTEXs). In general, both CH(4) and NMOC fluxes were all very small with positive and negative fluxes. The highest percentages of positive fluxes in this study (considering all quantified species) were observed at the hotspots, located mainly along cell perimeters of the conventional cell. The capacity of the cover soil for NMOC oxidation was investigated in microcosms incubated with CH(4) and oxygen (O(2)). The cover soil showed a relatively high capacity for CH(4) oxidation and simultaneous co-oxidation of the halogenated aliphatic compounds, especially at the conventional cell. Fully substituted carbons (TeCM, PCE, CFC-11, CFC-12, CFC-113, HFC-134a, and HCFC-141b) were not degraded in the presence of CH(4) and O(2). Benzene and toluene were also degraded with relative high rates. This study demonstrates that landfill soil covers show a significant potential for CH(4) oxidation and co-oxidation of NMOCs. PMID:18032020

  2. Modeling the effects of vegetation on methane oxidation and emissions through soil landfill final covers across different climates.

    PubMed

    Abichou, Tarek; Kormi, Tarek; Yuan, Lei; Johnson, Terry; Francisco, Escobar

    2015-02-01

    Plant roots are reported to enhance the aeration of soil by creating secondary macropores which improve the diffusion of oxygen into soil as well as the supply of methane to bacteria. Therefore, methane oxidation can be improved considerably by the soil structuring processes of vegetation, along with the increase of organic biomass in the soil associated with plant roots. This study consisted of using a numerical model that combines flow of water and heat with gas transport and oxidation in soils, to simulate methane emission and oxidation through simulated vegetated and non-vegetated landfill covers under different climatic conditions. Different simulations were performed using different methane loading flux (5-200 g m(-2) d(-1)) as the bottom boundary. The lowest modeled surface emissions were always obtained with vegetated soil covers for all simulated climates. The largest differences in simulated surface emissions between the vegetated and non-vegetated scenarios occur during the growing season. Higher average yearly percent oxidation was obtained in simulations with vegetated soil covers as compared to non-vegetated scenario. The modeled effects of vegetation on methane surface emissions and percent oxidation were attributed to two separate mechanisms: (1) increase in methane oxidation associated with the change of the physical properties of the upper vegetative layer and (2) increase in organic matter associated with vegetated soil layers. Finally, correlations between percent oxidation and methane loading into simulated vegetated and non-vegetated covers were proposed to allow decision makers to compare vegetated versus non-vegetated soil landfill covers. These results were obtained using a modeling study with several simplifying assumptions that do not capture the complexities of vegetated soils under field conditions. PMID:25475118

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

    PubMed

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

    2011-01-01

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

  4. Field-Scale Stable-Isotope Probing of Active Methanotrophs in a Landfill-Cover Soil

    NASA Astrophysics Data System (ADS)

    Schroth, M. H.; Henneberger, R.; Chiri, E.

    2012-12-01

    The greenhouse gas methane (CH4) is an important contributor to global climate change. While its atmospheric concentration is increasing, a large portion of produced CH4 never reaches the atmosphere, but is consumed by aerobic methane-oxidizing bacteria (MOB). The latter are ubiquitous in soils and utilize CH4 as sole source of energy and carbon. Among other methods, MOB may be differentiated based on characteristic phospholipid fatty acids (PLFA). Stable-isotope probing (SIP) on PLFA has been widely applied to identify active members of MOB communities in laboratory incubation studies, but results are often difficult to extrapolate to the field. Thus, novel field-scale approaches are needed to link activity and identity of MOB in their natural environment. We present results of field experiments in which we combined PLFA-SIP with gas push-pull tests (GPPTs) to label active MOB at the field-scale while simultaneously quantifying CH4 oxidation activity. During a SIP-GPPT, a mixture of reactive (here 13CH4, O2) and non-reactive tracer gases (e.g., Ar, Ne, He) is injected into the soil at a location of interest. Thereafter, gas flow is reversed and the gas mixture diluted with soil air is extracted from the same location and sampled periodically. Rate constants for CH4 oxidation can be calculated by analyzing breakthrough curves of 13CH4 and a suitable non-reactive tracer gas. SIP-GPPTs were performed in a landfill-cover soil, and feasibility of this novel approach was tested at several locations along a gradient of MOB activity and soil temperature. Soil samples were collected before and after SIP-GPPTs, total PLFA were extracted, and incorporation of 13C in the polar lipid fraction was analyzed. Potential CH4 oxidation rates derived from SIP-GPPTs were similar to those derived from regular GPPTs (using unlabeled CH4) performed at the same locations prior to SIP-GPPTs, indicating that application of 13CH4 did not adversely affect bacterial CH4 oxidation rates. Rates

  5. LANDFILL CONTAINMENT AND COVER SYSTEMS

    EPA Science Inventory

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

  6. The potential application of red mud and soil mixture as additive to the surface layer of a landfill cover system.

    PubMed

    Ujaczki, Éva; Feigl, Viktória; Molnár, Mónika; Vaszita, Emese; Uzinger, Nikolett; Erdélyi, Attila; Gruiz, Katalin

    2016-06-01

    Red mud, the by-product of aluminum production, has been regarded as a problematic residue all over the world. Its storage involves risks as evidenced by the Ajka red mud spill, an accident in Hungary where the slurry broke free, flooding the surrounding areas. As an immediate remediation measure more than 5cm thick red mud layer was removed from the flooded soil surface. The removed red mud and soil mixture (RMSM) was transferred into the reservoirs for storage. In this paper the application of RMSM is evaluated in a field study aiming at re-utilizing waste, decreasing cost of waste disposal and providing a value-added product. The purpose was to investigate the applicability of RMSM as surface layer component of landfill cover systems. The field study was carried out in two steps: in lysimeters and in field plots. The RMSM was mixed at ratios ranging between 0 and 50% w/w with low quality subsoil (LQS) originally used as surface layer of an interim landfill cover. The characteristics of the LQS+RMSM mixtures compared to the subsoil (LQS) and the RMSM were determined by physical-chemical, biological and ecotoxicological methods. The addition of RMSM to the subsoil (LQS) at up to 20% did not result any ecotoxic effect, but it increased the water holding capacity. In addition, the microbial substrate utilization became about triple of subsoil (LQS) after 10months. According to our results the RMSM mixed into subsoil (LQS) at 20% w/w dose may be applied as surface layer of landfill cover systems. PMID:27266315

  7. Methane oxidation in a neutral landfill cover soil: Influence of moisture content, temperature, and nitrogen-turnover

    SciTech Connect

    Boeckx, P.; Van Cleemput, O.

    1996-01-01

    Well-managed, aerated cover soils can have a mitigating effect on methane emission from landfills. The influence of moisture content, soil temperature, and N on the methane uptake capacity of a neutral landfill cover soil was examined. A soil moisture content of 15% w/w gave the maximum CH{sub 4} oxidation rate (2.36 ng CH{sub 4}{sup -1}g{sup -1} soil). When wetter, CH{sub 4} consumption was slower (e.g., 1.6 ng CH{sub 4} h{sup -1} g {sup -1} at 30% w/w) because of a limited gas diffusion. At lower soil moisture, microbial activity was reduced and consequently the oxidation capacity decreased (e.g., 0.84 ng CH{sub 4} {sup -1} g{sup -1} at 5% w/w). Optimum temperature was between 25 and 30{degrees}C. The calculated activation energy of the CH{sub 4} oxidation was 56.5 kj K{sup -1} mol{sup -1}. After NH4{sub 4}{sup +} addition, a negative linear correlation was found between the methane oxidation rate and the nitrous oxide flux (R{sup 2} = 0.96 Y1 = 2.7 - 0.44 x Y2). Addition of NO{sub 3}{sup -} had no significant effect on CH{sub 4} oxidation. The effect of organic residue amendments depended on their C/N ratios. Crop residues with a high C/N ratio (wheat [Triticum sativum L.] and maize [Zea mays L.] straw) stimulated N-immobilization and did not affect the methane-oxidizing capacity. On the other hand, addition of crop residues with low C/N ratios (potato [Solanum tuberosum L.] and sugar beet [Beta vulgaris cv. Altissima] leaves) stimulated N-mineralization, resulting in a strong inhibition of the methane oxidation. 38 refs., 4 figs., 2 tabs.

  8. Construction Costs of Six Landfill Cover Designs

    SciTech Connect

    Dwyer, S.F.

    1998-12-23

    A large-scale field demonstration comparing and contrasting final landfill cover designs has been constructed and is currently being monitored. Four alternative cover designs and two conventional designs (a RCRA Subtitle `D' Soil Cover and a RCRA Subtitle `C' Compacted Clay Cover) were constructed side-by-side for direct comparison. The demonstration is intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. This paper provides an overview of the construction costs of each cover design.

  9. Cost comparisons of alternative landfill final covers

    SciTech Connect

    Dwyer, S.F.

    1997-02-01

    A large-scale field demonstration comparing and contrasting final landfill cover designs has been constructed and is currently being monitored. Four alternative cover designs and two conventional designs (a RCRA Subtitle ``D`` Soil Cover and a RCRA Subtitle ``C`` Compacted Clay Cover) were constructed of uniform size, side-by-side. The demonstration is intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. This paper provides an overview of the construction costs of each cover design.

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

    PubMed

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

    2011-12-01

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

  11. Field water balance of landfill final covers.

    PubMed

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

    2004-01-01

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

  12. Field-scale tracking of active methane-oxidizing communities in a landfill cover soil reveals spatial and seasonal variability.

    PubMed

    Henneberger, Ruth; Chiri, Eleonora; Bodelier, Paul E L; Frenzel, Peter; Lüke, Claudia; Schroth, Martin H

    2015-05-01

    Aerobic methane-oxidizing bacteria (MOB) in soils mitigate methane (CH4 ) emissions. We assessed spatial and seasonal differences in active MOB communities in a landfill cover soil characterized by highly variable environmental conditions. Field-based measurements of CH4 oxidation activity and stable-isotope probing of polar lipid-derived fatty acids (PLFA-SIP) were complemented by microarray analysis of pmoA genes and transcripts, linking diversity and function at the field scale. In situ CH4 oxidation rates varied between sites and were generally one order of magnitude lower in winter compared with summer. Results from PLFA-SIP and pmoA transcripts were largely congruent, revealing distinct spatial and seasonal clustering. Overall, active MOB communities were highly diverse. Type Ia MOB, specifically Methylomonas and Methylobacter, were key drivers for CH4 oxidation, particularly at a high-activity site. Type II MOB were mainly active at a site showing substantial fluctuations in CH4 loading and soil moisture content. Notably, Upland Soil Cluster-gamma-related pmoA transcripts were also detected, indicating concurrent oxidation of atmospheric CH4 . Spatial separation was less distinct in winter, with Methylobacter and uncultured MOB mediating CH4 oxidation. We propose that high diversity of active MOB communities in this soil is promoted by high variability in environmental conditions, facilitating substantial removal of CH4 generated in the waste body. PMID:25186436

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

    SciTech Connect

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

    2011-12-15

    Highlights: > The effects of soil physical properties on gas transport parameters were investigated. > Higher values of D{sub p} and k{sub a} exhibited in the '+gravel' than the '-gravel' fraction at same soil-air content ({epsilon}). > Recent power law models for D{sub p} (WLR) and k{sub a} (RPL) were modified. > Model parameters were linearly related to easily measurable dry bulk density ({rho}{sub b}). - Abstract: Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, {rho}{sub b}, and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D{sub p}/D{sub o}, ratio of gas diffusion coefficients in soil and free air) and air permeability (k{sub a}) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting {rho}{sub b} values ranging from 1.40 to 2.10 g cm{sup -3}. Results showed that D{sub p} and k{sub a} values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2 mm) under variably-saturated conditions for a given soil-air content ({epsilon}), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D{sub p} and k{sub a} was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D{sub p}/D{sub f}, the ratio of measured D{sub p} to D{sub p} in total porosity (f), (ii) for air permeability k{sub a}/k{sub a,pF4.1}, the ratio of measured k{sub a} to k{sub a} at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content ({epsilon}) to total porosity (f) (air

  14. Performance of geotextiles in landfills covers

    SciTech Connect

    Reitz, L.J.; Holtz, R.D.

    1997-11-01

    As part of the research into the performance of geotextiles in landfill covers, 14 test pits were excavated in five landfill covers constructed between 1988 and 1992 in Washington State. Materials used in the drainage system were examined and documented. Specimens of geotextiles (all 8 oz/yd{sup 2}, needle punched nonwovens) as well as samples of the vegetative and sand drainage soils, were obtained for laboratory analyses. Laboratory tests indicated that the geotextiles satisfactorily performed their intended filtration function. No apparent migration of fines into the drainage layer was detected. The degree of clogging was evaluated by performing permittivity tests on specimens of the exhumed geotextiles, as retrieved and after washing. Washing typically resulted in permittivity increases on the order of 30 to 90 percent.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  16. Field Water Balance of Landfill Final Covers

    EPA Science Inventory

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

  17. TDR calibration for the alternative landfill cover demonstration (ALCD)

    SciTech Connect

    Lopez, J.; Dwyer, S.F.; Swanson, J.N.

    1997-09-01

    The Alternative Landfill Cover Demonstration is a large scale field test that compares the performance of various landfill cover designs in dry environments. An important component of the comparison is the change in the moisture content of the soils throughout the different cover test plots. Time Domain Reflectometry (TDR) is the primary method for the measurement of the volumetric moisture content. Each of the covers is composed of layers of varying types and densities of soils. The probes are therefore calibrated to calculate the volumetric moisture content in each of the different soils in order to gain the optimum performance of the TDR system. The demonstration plots are constructed in two phases; a different probe is used in each phase. The probe that is used in Phase 1 is calibrated for the following soils: compacted native soil, uncompacted native soil, compacted native soil mixed with 6% sodium bentonite by weight, and sand. The probe that is used in Phase 2 is calibrated for the following soils: compacted native soil, uncompacted native soil, and sand. In addition, the probes are calibrated for the varying cable lengths of the TDR probes. The resulting empirically derived equations allow for the calculation of in-situ volumetric moisture content of all of the varying soils throughout the cover test plots in the demonstration.

  18. Modeling of H2S migration through landfill cover materials.

    PubMed

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

    2014-01-15

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

  19. GEOSYNTHETIC CLAY LINERS (GCLS) IN LANDFILL COVERS

    EPA Science Inventory

    Low permeability, compacted clay linters are commonly required as a barrier to water infiltration in landfill covers. elatively new material, known as geosynthetic clay liner (GCL), has been proposed as an alternative to a compacted clay liner. CL has the practical advantages of ...

  20. Report: landfill alternative daily cover: conserving air space and reducing landfill operating cost.

    PubMed

    Haughey, R D

    2001-02-01

    Title 40, Part 258 of the Code of Federal Regulations, Solid Waste Disposal Facility Criteria, commonly referred to as Subtitle D, became effective on October 9, 1993. It establishes minimum criteria for solid waste disposal facility siting, design, operations, groundwater monitoring and corrective action, and closure and postclosure maintenance, while providing EPA-approved state solid waste regulatory programs flexibility in implementing the criteria. Section 258.21(a) [40 CFR 258.21(a)] requires owners or operators of municipal solid waste landfill (MSWLF) units to cover disposed solid waste with 30cm of earthen material at the end of the operating day, or at more frequent intervals, if necessary, to control disease vectors, fires, odours, blowing litter, and scavenging. This requirement is consistent with already existing solid waste facility regulations in many states. For many MSWLFs, applying daily cover requires the importation of soil which increases landfill operating costs. Daily cover also uses valuable landfill air space, reducing potential operating revenue and the landfill's operating life. 40 CFR 258.21 (b) allows the director of an approved state to approve alternative materials of an alternative thickness if the owner or operator demonstrates that the alternative material and thickness will control disease vectors, fires, odours, blowing litter, and scavenging without presenting a threat to human health and the environment. Many different types of alternative daily cover (ADC) are currently being used, including geosynthetic tarps, foams, garden waste, and auto shredder fluff. These materials use less air space than soil and can reduce operating costs. This paper discusses the variety of ADCs currently being used around the country and their applicability to different climates and operating conditions, highlighting the more unusual types of ADC, the types of demonstrations necessary to obtain approval of ADC, and the impact on landfill air space

  1. Partial oxidative conversion of methane to methanol through selective inhibition of methanol dehydrogenase in methanotrophic consortium from landfill cover soil.

    PubMed

    Han, Ji-Sun; Ahn, Chang-Min; Mahanty, Biswanath; Kim, Chang-Gyun

    2013-11-01

    Using a methanotrophic consortium (that includes Methylosinus sporium NCIMB 11126, Methylosinus trichosporium OB3b, and Methylococcus capsulatus Bath) isolated from a landfill site, the potential for partial oxidation of methane into methanol through selective inhibition of methanol dehydrogenase (MDH) over soluble methane monooxygenase (sMMO) with some selected MDH inhibitors at varied concentration range, was evaluated in batch serum bottle and bioreactor experiments. Our result suggests that MDH activity could effectively be inhibited either at 40 mM of phosphate, 100 mM of NaCl, 40 mM of NH4Cl or 50 μM of EDTA with conversion ratios (moles of CH3OH produced per mole CH4 consumed) of 58, 80, 80, and 43 %, respectively. The difference between extent of inhibition in MDH activity and sMMO activity was significantly correlated (n = 6, p < 0.05) with resultant methane to methanol conversion ratio. In bioreactor study with 100 mM of NaCl, a maximum specific methanol production rate of 9 μmol/mg h was detected. A further insight with qPCR analysis of MDH and sMMO coding genes revealed that the gene copy number continued to increase along with biomass during reactor operation irrespective of presence or absence of inhibitor, and differential inhibition among two enzymes was rather the key for methanol production. PMID:23963715

  2. [Depth Profiles of Methane Oxidation Kinetics and the Related Methanotrophic Community in a Simulated Landfill Cover].

    PubMed

    Xing, Zhi-lin; Zhao, Tian-tao; Gao, Yan-hui; He, Zhi; Yang, Xu; Peng, Xu-ya

    2015-11-01

    Simulated landfill cover with real time online monitoring system was developed using cover soils. Then the system started and the concentrations of bio-gas in various depths were continuously monitored, and it was found that the system ran continually and stably after 2-3 h when methane flux changed. After that, the relationship between regularity of methane oxidation and methane flux in landfill cover was analyzed. The results indicated that concentration of oxygen decreased with increasing methane flux when the depth was deeper than 20 cm, and no obvious correlation between oxygen concentration in landfill cover surface and methane flux, however, methane oxidation rate showed positive correlation with methane flux in various depths (range of R2 was 0.851-0.999). Kinetics of CH4 oxidation in landfill cover was fitted by CH4 -O2 dual-substrate model (range of R2 was 0.902-0.955), the half-saturation constant K(m) increasing with depth was 0.157-0.729 in dynamic condition. Finally, methanotrophs community structure in original cover soil sample and that in simulated landfill cover were investigated by high-throughout sequencing technology, and the statistics indicated that the abundance and species of methanotrophs in simulated landfill cover significantly increased compared with those in original cover soil sample, and type I methanotrophs including Methylobacter and Methylophilaceae and type II methanotrophs Methylocystis were dominant species. PMID:26911022

  3. METHANE PHYTOREMEDIATION BY VEGETATIVE LANDFILL COVER SYSTEMS

    EPA Science Inventory

    Landfill gas, consisting of methane and other gases, is produced from organic compounds degrading in landfills, contributes to global climate change, is toxic to various types of vegetation, and may pose a combustion hazard at higher concentrations. New landfills are required to ...

  4. Fly ash in landfill top covers - a review.

    PubMed

    Brännvall, E; Kumpiene, J

    2016-01-01

    Increase of energy recovery from municipal solid waste by incineration results in the increased amounts of incineration residues, such as fly ash, that have to be taken care of. Material properties should define whether fly ash is a waste or a viable resource to be used for various applications. Here, two areas of potential fly ash application are reviewed: the use of fly ash in a landfill top cover either as a liner material or as a soil amendment in vegetation layer. Fly ashes from incineration of three types of fuel are considered: refuse derived fuel (RDF), municipal solid waste incineration (MSWI) and biofuel. Based on the observations, RDF and MSWI fly ash is considered as suitable materials to be used in a landfill top cover liner. Whereas MSWI and biofuel fly ashes based on element availability for plant studies, could be considered suitable for the vegetation layer of the top cover. Responsible application of MSWI ashes is, however, warranted in order to avoid element accumulation in soil and elevation of background values over time. PMID:26701627

  5. EVALUATION OF MUNICIPAL SOLID WASTE LANDFILL COVER DESIGNS

    EPA Science Inventory

    The HELP (Hydrologic Evaluation of Landfill Performance) Model was used to evaluate the hydrologic behavior of a series of one-, two-, and three-layer cover designs for municipal solid waste landfill cover designs were chosen to isolate the effects of features such as surface veg...

  6. EVAPOTRANSPIRATION AND CAPILLARY BARRIER FINAL LANDFILL COVERS FACT SHEET

    EPA Science Inventory

    The fact sheet provides an overview of two alternative landfill cover designs. It briefly describes advantages and limitations, performance, costs, design and site considerations, and monitoring parameters associated with these cover designs. The document also includes 20 site ...

  7. Digested sewage sludge solidification by converter slag for landfill cover.

    PubMed

    Kim, Eung-Ho; Cho, Jin-Kyu; Yim, Soobin

    2005-04-01

    A new technology for solidification of digested sewage sludge referred to as converter slag solidification (CSS) has been developed using converter slag as the solidifying agent and quick lime as the solidifying aid. The CSS technology was investigated by analyzing the physicochemical properties of solidified sludge and determining its microstructural characteristics. The feasibility of using solidified sludge as a landfill cover material was considered in the context of the economical recycling of waste. Sludge solidified using the CSS technology exhibited geotechnical properties that are appropriate for replacing currently used cover soil. Microscopic analyses using XRD, SEM and EDS revealed that the main hydrated product of solidification was CSH (CaO . SiO2 . nH2O), which may play an important role in the effective setting process. Negligible leaching of heavy metals from the solidified sludge was observed. The solidification process of the hydrated sludge, slag and quicklime eliminated the coliform bacteria. Recycled sewage sludge solidified using CCS technology could be used as an effective landfill cover. PMID:15763091

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

    PubMed

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

    2011-05-01

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

  9. Models for hydrologic design of evapotranspiration landfill covers.

    PubMed

    Hauser, Victor L; Gimon, Dianna M; Bonta, James V; Howell, Terry A; Malone, Robert W; Williams, Jimmy R

    2005-09-15

    The technology used in landfill covers is changing, and an alternative cover called the evapotranspiration (ET) landfill cover is coming into use. Important design requirements are prescribed by Federal rules and regulations for conventional landfill covers but not for ET landfill covers. There is no accepted hydrologic model for ET landfill cover design. This paper describes ET cover requirements and design issues, and assesses the accuracy of the EPIC and HELP hydrologic models when used for hydrologic design of ET covers. We tested the models against high-quality field measurements available from lysimeters maintained by the Agricultural Research Service of the U.S. Department of Agriculture at Coshocton, Ohio, and Bushland, Texas. The HELP model produced substantial errors in estimating hydrologic variables. The EPIC model estimated ET and deep percolation with errors less than 7% and 5%, respectively, and accurately matched extreme events with an error of less than 2% of precipitation. The EPIC model is suitable for use in hydrologic design of ET landfill covers. PMID:16201652

  10. On the performance of capillary barriers as landfill cover

    NASA Astrophysics Data System (ADS)

    Kämpf, M.; Montenegro, H.

    Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m). In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.

  11. Field measurements of frost penetration into a landfill cover that uses a paper sludge barrier

    SciTech Connect

    Moo-Young, H.K.; LaPlante, C.; Zimmie, T.F.; Quiroz, J.

    1999-07-01

    Frost penetration is a major environmental concern in landfill design. Freezing and thawing cycles may deteriorate the permeability of the liner or cap. In this study, the depth of frost penetration into a landfill cover that uses paper sludge as the impermeable barrier (the Hubbardston landfill in Massachusetts) was measured using a frost measurement system. A thermistor probe measured the temperature at various depths. Although temperature measurements are important, soil resistivity measurements are required to accurately predict the freezing level, since soil resistivity increases greatly upon freezing. A conductivity probe measured the half-bridge voltage between conductivity rings and a ground rod. Data were collected in data loggers. The data collected from 1992--1996 showed that the frost level did not penetrate the paper sludge capping layer. Heavy snow cover throughout the winters decreased the depth of frost penetration by insulating the landfill. The high water content in the sludge also contributed to the lack of freezing.

  12. [Experiment and numerical simulation of percolation control using evapotranspirative landfill cover system].

    PubMed

    Liu, Chuan-shun; Zhao, Hui; Luo, Ji-wu

    2009-01-01

    An Evapotranspirative Landfill Cover (ET Landfill Cover) is a simple and economical percolation control system that involves a monolithic soil layer with a vegetative cover.Percolation control in an ET cover system relies on the storage of moisture within the cover soils during precipitation events and subsequently returns it to the atmosphere by evapotranspiration. Percolation control experiments of a bare soil cover and 5 different ET covers were implemented in comprehensive experimental station of water environment of Wuhan University and the water balance calculation of each cover system was conducted, the results shown that the ET cover of 60 cm loamy soil layer with shrub was the most effective among the 6 experimental disposals. However, the experiments demonstrated 60 cm thick of soil layer was not enough to prevent percolation during rainy season and keep the shrub alive during drought season without irrigation. So the Hydrus 2D was selected to simulate the soil water movement in ET covers with different cover thicknesses, the simulations shown that the optimal ET cover in Wuhan area should be 120-140 cm loamy soil layer with shrub. PMID:19353895

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

    PubMed

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

    2014-06-15

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

  14. Landfill cover performance monitoring using time domain reflectometry

    SciTech Connect

    Neher, E.R.; Cotten, G.B.; McElroy, D.

    1998-03-01

    Time domain reflectometry (TDR) systems were installed to monitor soil moisture in two newly constructed landfill covers at the Idaho National Engineering and Environmental Laboratory. Each TDR system includes four vertical arrays with each array consisting of four TDR probes located at depths of 15, 30, 45, and 60 cm. The deepest probes at 60 cm were installed beneath a compacted soil layer to analyze infiltration through the compacted layer. Based on the TDR data, infiltration through the two covers between March and October, 1997 ranged from less than measurable to 1.5 cm. However, due to a prohibition on penetrating the buried waste and resulting limits on probe placement depths, deeper percolation was not evaluated. Some of the advantages found in the application of TDR for infiltration monitoring at this site are the relative low cost and rugged nature of the equipment. Also, of particular importance, the ability to collect frequent moisture measurements allows the capture and evaluation of soil moisture changes resulting from episodic precipitation events. Disadvantages include the inability to install the probes into the waste, difficulties in interpretation of infiltration during freeze/thaw periods, and some excessive noise in the data.

  15. Long-term performance of landfill covers - results of lysimeter test fields in Bavaria (Germany).

    PubMed

    Henken-Mellies, Wolf-Ulrich; Schweizer, Andreas

    2011-01-01

    A comprehensive study was conducted to examine the performance and possible changes in the effectiveness of landfill surface covers. Three different profiles of mineral landfill caps were examined. The results of precipitation and flow measurements show distinct seasonal differences which are typical for middle-European climatic conditions. In the case of the simple landfill cap design consisting of a thick layer of loamy sand, approximately 100-200 L m(-2) of annual seepage into the landfill body occurs during winter season. The three-layer systems of the two other test fields performed much better. Most of the water which percolated through the top soil profile drained sideways in the drainage layer. Only 1-3% of precipitation percolated through the sealing layer. The long-term effectiveness of the mineral sealing layer depended on the ability of the top soil layer to protect it from critical loss of soil water/critical increase of suction. In dry summers there was even a loss in soil water content at the base of the 2.0 m thick soil cover. The results of this study demonstrate the importance of the long-term aspect when assessing the effectiveness of landfill covers: The hydraulic conductivity at the time of construction gives only an initial (minimum) value. The hydraulic conductivity of the compacted clay layer or of the geosynthetic clay liner may increase substantially, if there is no long-lasting protection against desiccation (by a thick soil cover or by a geomembrane). This has to be taken into account in landfill cover design. PMID:20937619

  16. Hydrologic studies of multilayered landfill covers for closure of waste landfills at Los Alamos, New Mexico

    SciTech Connect

    Nyhan, J.W.; Langhorst, G.J.; Martin, C.E.; Martinez, J.L.; Schofield, T.G.

    1993-06-01

    The Los Alamos National Laboratory examined water balance relationships for four different landfill cover designs containing engineered barriers. These field experiments were performed at Los Alamos, New Mexico, USA, in 1.0- by 10.0-m plots with downhill slopes of 5, 10, 15 and 25%. Field measurements of seepage, precipitation, interflow, runoff, and soil water content were collected in each of the 16 plots representing four slopes each with four cover designs: Conventional, EPA, Loam Capillary Barrier and Clay Loam Capillary Barrier. A seepage collection system was installed beneath each cover design to evaluate the influence of slope length on seepage using a series of four metal pans filled with medium gravel that were placed end-to-end in the bottom of each field plot. An automated waterflow datalogging system was used to collect hourly seepage, interflow and runoff data and consisted of 100 100-liter tanks, each of which was equipped with an ultrasonic liquid-level sensor and a motor-operated ball valve used to drain the tank. Soil water content was routinely monitored every six hours at each of 212 locations throughout the 16 plots with time domain reflectrometry (TDR) techniques using an automated and multiplexed measurement system.

  17. Evaluation of the odour reduction potential of alternative cover materials at a commercial landfill.

    PubMed

    Solan, P J; Dodd, V A; Curran, T P

    2010-02-01

    The availability of virgin soils and traditional landfill covers are not only costly and increasingly becoming scarce, but they also reduce the storage capacity of landfill. The problem can be overcome by the utilisation of certain suitable waste streams as alternative landfill covers. The objective of this study was to assess the suitability of Construction & Demolition fines (C&D), Commercial & Industrial fines (C&I) and woodchip (WC) as potential landfill cover materials in terms of odour control. Background odour analysis was conducted to determine if any residual odour was emitted from the cover types. It was deemed negligible for the three materials. The odour reduction performance of each of the materials was also examined on an area of an active landfill site. A range of intermediate cover compositions were also studied to assess their performance. Odour emissions were sampled using a Jiang hood and analysed. Results indicate that the 200 mm deep combination layer of C&D and wood chip used on-site is adequate for odour abatement. The application of daily cover was found to result in effective reduction allowing for the background odour of woodchip. PMID:19786346

  18. Field Performance Of Three Compacted Clay Landfill Covers

    EPA Science Inventory

    A study was conducted at sites in subtropical Georgia, seasonal and humid Iowa, and arid southeastern California to evaluate the field hydrology of compacted clay covers for final closure of landfills. Water balance of the covers was monitored with large (10 by 20 m ), instrumen...

  19. Analysis of Vegetative on Six Different Landfill Cover Profiles in an Arid Environment.

    SciTech Connect

    Dwyer, Stephen F.; McClellan, Yvonne; Reavis, Bruce A.; Dwyer, Brian P.; Newman, Gretchen; Wolters, Gale

    2005-05-01

    A large-scale field demonstration comparing final landfill cover designs was constructed and monitored at Sandia National Laboratories in Albuquerque, New Mexico. Two conventional designs (a RCRA Subtitle 'D' Soil Cover and a RCRA Subtitle 'C' Compacted Clay Cover) were constructed side-by-side with four alternative cover test plots designed for arid environments. The demonstration was intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. A portion of this project involves the characterization of vegetation establishment and growth on the landfill covers. The various prototype landfill covers were expected to have varying flux rates (Dwyer et al 2000). The landfill covers were further expected to influence vegetation establishment and growth, which may impact site erosion potential and long-term site integrity. Objectives of this phase were to quantify the types of plants occupying each site, the percentage of ground covered by these plants, the density (number of plants per unit area) of plants, and the plant biomass production. The results of this vegetation analysis are presented in this report.3 DRAFT07/06/14AcknowledgementsWe would like to thank all technical and support staff from Sandia and the USDA Forest Service's Rocky Mountain Station not included in the authors' list of this document for their valuable contributions to this research. We would also like to acknowledge the Department of Energy's Subsurface Contaminants Focus Area for funding this work.4

  20. Observations on the methane oxidation capacity of landfill soils.

    PubMed

    Chanton, Jeffrey; Abichou, Tarek; Langford, Claire; Spokas, Kurt; Hater, Gary; Green, Roger; Goldsmith, Doug; Barlaz, Morton A

    2011-05-01

    The objective of this study was to determine the role of CH(4) loading to a landfill cover in the control of CH(4) oxidation rate (gCH(4)m(-2)d(-1)) and CH(4) oxidation efficiency (% CH(4) oxidation) in a field setting. Specifically, we wanted to assess how much CH(4) a cover soil could handle. To achieve this objective we conducted synoptic measurements of landfill CH(4) emission and CH(4) oxidation in a single season at two Southeastern USA landfills. We hypothesized that percent oxidation would be greatest at sites of low CH(4) emission and would decrease as CH(4) emission rates increased. The trends in the experimental results were then compared to the predictions of two differing numerical models designed to simulate gas transport in landfill covers, one by modeling transport by diffusion only and the second allowing both advection and diffusion. In both field measurements and in modeling, we found that percent oxidation is a decreasing exponential function of the total CH(4) flux rate (CH(4) loading) into the cover. When CH(4) is supplied, a cover's rate of CH(4) uptake (gCH(4)m(-2)d(-2)) is linear to a point, after which the system becomes saturated. Both field data and modeling results indicate that percent oxidation should not be considered as a constant value. Percent oxidation is a changing quantity and is a function of cover type, climatic conditions and CH(4) loading to the bottom of the cover. The data indicate that an effective way to increase the % oxidation of a landfill cover is to limit the amount of CH(4) delivered to it. PMID:20889326

  1. Transformation of a landfill covering amended with municipal waste compost, Perugia, Italy.

    PubMed

    Businelli, Mario; Calandra, Rolando; Pagliai, Marcello; Businelli, Daniela; Gigliotti, Giovanni; Grasselli, Olga; Said-Pullicino, Daniel; Leccese, Angelo

    2007-01-01

    This research deals with the transformation of an anthropomorphous landfill covering composed of a fill soil mixed with mechanically separated municipal waste compost. The study site was a municipal landfill near Perugia, Italy. Throughout the years, waste disposal in the landfill was performed by burial in horizontal layers, each one representing a yearly disposal. The external front of the landfill thus represented the yearly disposal over a 10-yr period starting in 1993. Temporal changes in the anthropomorphous soil over this period were studied by examining and describing soil profiles, and by collecting and analyzing soil samples from the 1993, 1994, 1997, and 2001 disposals. The samples were subjected to a series of physical, chemical, and biochemical analyses. The results obtained suggest that over a 10-yr period the top layer gained a pedological structure (subangular blocky and/or crumb) giving rise to an A horizon. Improved soil structure was confirmed by an increase in macroporosity, particularly for pores larger than 50 microm, measured by image analysis of soil thin sections. Total extractable carbon showed an increase in the content of humic substances, evidenced by parameters of humification. Enzymatic activities in the A and C1 horizons were also indicative of soil evolution and may serve as a valid indicator for monitoring the evolution of anthropogenic soils containing municipal waste compost. PMID:17215234

  2. 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. PMID:19787350

  3. Alternative landfill cover technology demonstration at Kaneohe Marine Corps Base Hawaii

    SciTech Connect

    Karr, L.A.; Harre, B.; Hakonson, T.E.

    1997-12-31

    Surface covers to control water infiltration to waste buried in landfills will be the remediation alternative of choice for most hazardous and sanitary landfills operated by the Department of Defense. Although surface covers are the least expensive method of remediation for landfills, they can still be expensive solutions. Conventional wisdom suggests that landfill capping technology is well developed as evidenced by the availability of EPA guidance for designing and constructing what has become known as the {open_quotes}RCRA Cap{close_quotes}. In practice, however, very little testing of the RCRA cap, or any other design, has been done to evaluate how effective these designs are in limiting infiltration of water into waste. This paper describes a low cost alternative to the {open_quotes}RCRA Cap{close_quotes} that is being evaluated at Marine Corps Base Hawaii (MCBH) Kaneohe Bay. This study uses an innovative, simple and inexpensive concept to manipulate the fate of water falling on a landfill. The infiltration of water through the cap will be controlled by combining the evaporative forces of vegetation to remove soil water, with engineered structures that limit infiltration of precipitation into the soil. This approach relies on diverting enough of the annual precipitation to runoff, so that the water that does infiltrate into the soil can easily be removed by evapotranspiration.

  4. Soil gas investigations at the Sanitary Landfill

    SciTech Connect

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

    1992-07-01

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

  5. Soil gas investigations at the Sanitary Landfill

    SciTech Connect

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

    1992-07-01

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

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

    PubMed

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

    2015-12-15

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

  7. Large-Scale Field Study of Landfill Covers at Sandia National Laboratories

    SciTech Connect

    Dwyer, S.F.

    1998-09-01

    A large-scale field demonstration comparing final landfill cover designs has been constructed and is currently being monitored at Sandia National Laboratories in Albuquerque, New Mexico. Two conventional designs (a RCRA Subtitle `D' Soil Cover and a RCRA Subtitle `C' Compacted Clay Cover) were constructed side-by-side with four alternative cover test plots designed for dry environments. The demonstration is intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. This paper presents an overview of the ongoing demonstration.

  8. Field performance of alternative landfill covers vegetated with cottonwood and eucalyptus trees.

    PubMed

    Abichou, Tarek; Musagasa, Jubily; Yuan, Lei; Chanton, Jeff; Tawfiq, Kamal; Rockwood, Donald; Licht, Louis

    2012-01-01

    A field study was conducted to assess the ability of landfill covers to control percolation into the waste. Performance of one conventional cover was compared to that of two evapotranspiration (ET) tree covers, using large (7 x 14 m) lined lysimeters at the Leon County Solid Waste management facility in Tallahassee, Florida. Additional unlined test sections were also constructed and monitored in order to compare soil water storage, soil temperature, and tree growth inside lysimeters and in unlined test sections. The unlined test sections were in direct contact with landfill gas. Surface runoff on the ET covers was a small proportion of the water balance (1% of precipitation) as compared to 13% in the conventional cover. Percolation in the ET covers averaged 17% and 24% of precipitation as compared to 33% in the conventional cover. On average, soil water storage was higher in the lined lysimeters (429 mm) compared to unlined test sections (408 mm). The average soil temperature in the lysimeters was lower than in the unlined test sections. The average tree height inside the lysimeters was not significantly lower (8.04 mfor eucalyptus and 7.11 mfor cottonwood) than outside (8.82 m for eucalyptus and 8.01 m for cottonwood). ET tree covers vegetated with cottonwood or eucalyptus are feasible for North Florida climate as an alternative to GCL covers. PMID:22574380

  9. An Interactive Real-time Decision Support System for Leachate Irrigation on Evapotranspiration Landfill Covers

    NASA Astrophysics Data System (ADS)

    Wang, Y.

    2015-12-01

    Landfill disposal is still the most common and economical practice for municipal solid waste in most countries. However, heavily polluted leachate generated by excess rainwater percolating through the landfill waste is the major drawback of this practice. Evapotranspiration (ET) cover systems are increasingly being used as alternative cover systems to minimize percolation by evapotranspiration. Leachate recirculation is one of the least expensive options for leachate treatment. The combination of ET cover systems and leachate recirculation can be an economical and environment-friendly practice for landfill leachate management. An interactive real-time decision support system is being developed to better manage leachate irrigation using historical and forecasting weather data, and real time soil moisture data. The main frame of this system includes soil water modules, and plant-soil modules. An inverse simulation module is also included to calibrate certain parameters based on observed data when necessary. It would be an objectives-oriented irrigation management tool to minimize landfill operation costs and negative environmental impacts.

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

    SciTech Connect

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

    2011-05-15

    Research highlights: > Plants influence gas profile and methane oxidation in landfill covers. > Plants regulate water content and increase the availability of oxygen for methane oxidation. > Plant species with deep roots like alfalfa showed more stimulation of methane oxidation than plants with shallow root systems like grasses. - Abstract: Methane is an important greenhouse gas emitted from landfill sites and old waste dumps. Biological methane oxidation in landfill covers can help to reduce methane emissions. To determine the influence of different plant covers on this oxidation in a compost layer, we conducted a lysimeter study. We compared the effect of four different plant covers (grass, alfalfa + grass, miscanthus and black poplar) and of bare soil on the concentration of methane, carbon dioxide and oxygen in lysimeters filled with compost. Plants were essential for a sustainable reduction in methane concentrations, whereas in bare soil, methane oxidation declined already after 6 weeks. Enhanced microbial activity - expected in lysimeters with plants that were exposed to landfill gas - was supported by the increased temperature of the gas in the substrate and the higher methane oxidation potential. At the end of the first experimental year and from mid-April of the second experimental year, the methane concentration was most strongly reduced in the lysimeters containing alfalfa + grass, followed by poplar, miscanthus and grass. The observed differences probably reflect the different root morphology of the investigated plants, which influences oxygen transport to deeper compost layers and regulates the water content.

  11. Predicted performance of clay-barrier landfill covers in arid and semi-arid environments.

    PubMed

    Sadek, S; Ghanimeh, S; El-Fadel, M

    2007-01-01

    Conventional landfill cover systems for municipal solid waste include low-permeability compacted clay barriers to minimize infiltration into the landfilled waste. Such layers are vulnerable in climates where arid to semi-arid conditions prevail, whereby the clay cover tends to desiccate and crack, resulting in drastically higher infiltration, i.e., lower cover efficiency. To date, this phenomenon, which has been reported in field observations, has not been adequately assessed. In this paper, the performance of a cover system solely relying on a clay barrier was simulated using a numerical finite element formulation to capture changes in the clay layer and the corresponding modified hydraulic characteristics. The cover system was guided by USEPA Subtitle-D minimum requirements and consisted of a clay layer underlying a protective vegetated soil. The intrinsic characteristics of the clay barrier and vegetative soil cover, including their saturated hydraulic conductivities and their soil-water characteristic curves, were varied as warranted to simulate intact or "cracked" conditions as determined through the numerical analyses within the proposed methodology. The results indicate that the levels of percolation through the compromised or cracked cover were up to two times greater than those obtained for intact covers, starting with an intact clay hydraulic conductivity of 10(-5)cm/s. PMID:16987648

  12. DESIGN AND CONSTRUCTION OF COVERS FOR SOLID WASTE LANDFILLS

    EPA Science Inventory

    The report provides guidelines in selection, design, and construction of cover for management of municipal, industrial, and hazardous solid wastes (with the exception of radioactive waste). Natural soils as cover are the principal subject; however, synthetic membranes, chemicals,...

  13. Evaluation of methane oxidation activity in waste biocover soil during landfill stabilization.

    PubMed

    He, Ruo; Wang, Jing; Xia, Fang-Fang; Mao, Li-Juan; Shen, Dong-Sheng

    2012-10-01

    Biocover soil has been demonstrated to have high CH(4) oxidation capacity and is considered as a good alternative cover material to mitigate CH(4) emission from landfills, yet the response of CH(4) oxidation activity of biocover soils to the variation of CH(4) loading during landfill stabilization is poorly understood. Compared with a landfill cover soil (LCS) collected from Hangzhou Tianziling landfill cell, the development of CH(4) oxidation activity of waste biocover soil (WBS) was investigated using simulated landfill systems in this study. Although a fluctuation of influent CH(4) flux occurred during landfill stabilization, the WBS covers showed a high CH(4) removal efficiency of 94-96% during the entire experiment. In the LCS covers, the CH(4) removal efficiencies varied with the fluctuation of CH(4) influent flux, even negative ones occurred due to the storage of CH(4) in the soil porosities after the high CH(4) influent flux of ~137 gm(-2) d(-1). The lower concentrations of O(2) and CH(4) as well as the higher concentration of CO(2) were observed in the WBS covers than those in the LCS covers. The highest CH(4) oxidation rates of the two types of soil covers both occurred in the bottom layer (20-30 cm). Compared to the LCS, the WBS showed higher CH(4) oxidation activity and methane monooxygenase activity over the course of the experiment. Overall, this study indicated the WBS worked well for the fluctuation of CH(4) influent flux during landfill stabilization. PMID:22776254

  14. Gas breakthrough and emission through unsaturated compacted clay in landfill final cover

    SciTech Connect

    Ng, C.W.W.; Chen, Z.K.; Coo, J.L.; Chen, R.; Zhou, C.

    2015-10-15

    Highlights: • Explore feasibility of unsaturated clay as a gas barrier in landfill cover. • Gas breakthrough pressure increases with clay thickness and degree of saturation. • Gas emission rate decreases with clay thickness and degree of saturation. • A 0.6 m-thick clay layer may be sufficient to meet gas emission rate limit. - Abstract: Determination of gas transport parameters in compacted clay plays a vital role for evaluating the effectiveness of soil barriers. The gas breakthrough pressure has been widely studied for saturated swelling clay buffer commonly used in high-level radioactive waste disposal facility where the generated gas pressure is very high (in the order of MPa). However, compacted clay in landfill cover is usually unsaturated and the generated landfill gas pressure is normally low (typically less than 10 kPa). Furthermore, effects of clay thickness and degree of saturation on gas breakthrough and emission rate in the context of unsaturated landfill cover has not been quantitatively investigated in previous studies. The feasibility of using unsaturated compacted clay as gas barrier in landfill covers is thus worthwhile to be explored over a wide range of landfill gas pressures under various degrees of saturation and clay thicknesses. In this study, to evaluate the effectiveness of unsaturated compacted clay to minimize gas emission, one-dimensional soil column tests were carried out on unsaturated compacted clay to determine gas breakthrough pressures at ultimate limit state (high pressure range) and gas emission rates at serviceability limit state (low pressure range). Various degrees of saturation and thicknesses of unsaturated clay sample were considered. Moreover, numerical simulations were carried out using a coupled gas–water flow finite element program (CODE-BRIGHT) to better understand the experimental results by extending the clay thickness and varying the degree of saturation to a broader range that is typical at different

  15. EVALUATION OF HYDROLOGIC MODELS IN THE DESIGN OF STABLE LANDFILL COVERS

    EPA Science Inventory

    The study evaluates the utility of two hydrologic models in designing stable landfill cover systems. The models evaluated were HELP (Hydrologic Evaluation of Landfill Performance) and CREAMS (Chemicals, Runoff, and Erosion from Agricultural Management Systems). Studies of paramet...

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

    PubMed

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

    2011-05-01

    Methane is an important greenhouse gas emitted from landfill sites and old waste dumps. Biological methane oxidation in landfill covers can help to reduce methane emissions. To determine the influence of different plant covers on this oxidation in a compost layer, we conducted a lysimeter study. We compared the effect of four different plant covers (grass, alfalfa+grass, miscanthus and black poplar) and of bare soil on the concentration of methane, carbon dioxide and oxygen in lysimeters filled with compost. Plants were essential for a sustainable reduction in methane concentrations, whereas in bare soil, methane oxidation declined already after 6 weeks. Enhanced microbial activity - expected in lysimeters with plants that were exposed to landfill gas - was supported by the increased temperature of the gas in the substrate and the higher methane oxidation potential. At the end of the first experimental year and from mid-April of the second experimental year, the methane concentration was most strongly reduced in the lysimeters containing alfalfa+grass, followed by poplar, miscanthus and grass. The observed differences probably reflect the different root morphology of the investigated plants, which influences oxygen transport to deeper compost layers and regulates the water content. PMID:20888746

  17. Decontamination of landfill leachate by soil infiltration.

    PubMed

    Wong, M H; Leung, K C

    1989-12-01

    A soil column study was conducted to evaluate the efficiency of soil to attenuate pollutants in landfill leachate. It was found that more than 60% of the initial alkalinity, COD, and total nitrogen was removed after the leachate had percolated through the soil column. Lower efficiencies were observed for the removal of dissolved cations, ammonia nitrogen, and nitrate nitrogen. When previously percolated leachate was recirculated through the soil column, significant removal (93.6%) of ammonia nitrogen was achieved. Moreover, a further reduction in COD, total nitrogen, nitrate nitrogen, and potassium was evident. Bioassay tests of seed germination and root growth of Brassica chinensis were performed to compare the phytotoxicities of untreated, percolated, and recirculated leachates. The phytotoxicity was reduced by both treatments, with the greatest detoxification observed in the leachate recirculation treatment. The values of pH and Olsen phosphorus were significantly reduced (P less than 0.01) in the treated column soil, whereas significant increases (P less than 0.05) in electrical conductivity (EC), various forms of nitrogen, exchangeable sodium percentage (ESP), potassium, magnesium, zinc, and iron were observed. EC, ESP, potassium, magnesium, sodium, iron, and various forms of nitrogen accumulated at the soil surface (10 cm). On the other hand, manganese was deposited at 20 to 50 cm below the soil surface of the treated column. PMID:2604902

  18. Gas breakthrough and emission through unsaturated compacted clay in landfill final cover.

    PubMed

    Ng, C W W; Chen, Z K; Coo, J L; Chen, R; Zhou, C

    2015-10-01

    Determination of gas transport parameters in compacted clay plays a vital role for evaluating the effectiveness of soil barriers. The gas breakthrough pressure has been widely studied for saturated swelling clay buffer commonly used in high-level radioactive waste disposal facility where the generated gas pressure is very high (in the order of MPa). However, compacted clay in landfill cover is usually unsaturated and the generated landfill gas pressure is normally low (typically less than 10 kPa). Furthermore, effects of clay thickness and degree of saturation on gas breakthrough and emission rate in the context of unsaturated landfill cover has not been quantitatively investigated in previous studies. The feasibility of using unsaturated compacted clay as gas barrier in landfill covers is thus worthwhile to be explored over a wide range of landfill gas pressures under various degrees of saturation and clay thicknesses. In this study, to evaluate the effectiveness of unsaturated compacted clay to minimize gas emission, one-dimensional soil column tests were carried out on unsaturated compacted clay to determine gas breakthrough pressures at ultimate limit state (high pressure range) and gas emission rates at serviceability limit state (low pressure range). Various degrees of saturation and thicknesses of unsaturated clay sample were considered. Moreover, numerical simulations were carried out using a coupled gas-water flow finite element program (CODE-BRIGHT) to better understand the experimental results by extending the clay thickness and varying the degree of saturation to a broader range that is typical at different climate conditions. The results of experimental study and numerical simulation reveal that as the degree of saturation and thickness of clay increase, the gas breakthrough pressure increases but the gas emission rate decreases significantly. Under a gas pressure of 10 kPa (the upper bound limit of typical landfill gas pressure), a 0.6m or thicker

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

    PubMed

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

    2011-05-01

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

  20. Assessing the performance of a cold region evapotranspiration landfill cover using lysimetry and electrical resistivity tomography.

    PubMed

    Schnabel, William E; Munk, Jens; Abichou, Tarek; Barnes, David; Lee, William; Pape, Barbara

    2012-01-01

    In order to test the efficacy ofa cold-region evapotranspiration (ET) landfill cover against a conventional compacted clay (CCL) landfill cover, two pilot scale covers were constructed in side-by-side basin lysimeters (20m x 10m x 2m) at a site in Anchorage, Alaska. The primary basis of comparison between the two lysimeters was the percolation of moisture from the bottom of each lysimeter. Between 30 April 2005 and 16 May 2006, 51.5 mm of water percolated from the ET lysimeter, compared to 50.6 mm for the the CCL lysimeter. This difference was not found to be significant at the 95% confidence level. As part of the project, electrical resistivity tomography (ERT) was utilized to measure and map soil moisture in ET lysimeter cross sections. The ERT-generated cross sections were found to accurately predict the onset and duration of lysimeter percolation. Moreover, ERT-generated soil moisture values demonstrated a strong linear relationship to lysimeter percolation rates (R-Squared = 0.92). Consequently, ERT is proposed as a reliable tool for assessing the function of field scale ET covers in the absence of drainage measurement devices. PMID:22574381

  1. Soil contamination in landfills: a case study of a landfill in Czech Republic

    NASA Astrophysics Data System (ADS)

    Adamcová, D.; Vaverková, M. D.; Bartoň, S.; Havlíček, Z.; Břoušková, E.

    2016-02-01

    A phytotoxicity test was determined to assess ecotoxicity of landfill soil. Sinapis alba L. was used as a bioindicator of heavy metals. Soil samples 1-8, which were taken from the landfill body, edge of the landfill body, and its vicinity meet the limits for heavy metals Co, Cd, Pb, and Zn specified in the applicable legislation. Hg and Mn threshold values are not established in legislation, but values have been determined for the needs of the landfill operator. For heavy metals Cr, Cu, and Ni sample 2 exceeded the threshold values, which attained the highest values of all the samples tested for Cr, Cu, and Ni. For Cr and Ni the values were several times higher than values of the other samples. The second highest values for Cr, Cu, and Ni showed sample 6 and 7. Both samples exceeded the set limits. An increase in plant biomass was observed in plants growing on plates with soil samples, but no changes in appearance, slow growth, or necrotic lesions appeared. Ecotoxicity tests show that tested soils (concentration of 50 %) collected from the landfill body, edge of the landfill body, and its vicinity reach high percentage values of germination capacity of seeds of Sinapis alba L. (101-137 %). At a concentration of 25 %, tested soil samples exhibit lower values of germination capacity - in particular samples 3 to 8 - yet the seed germination capacity in all eight samples of tested soils ranges between 86 and 137 %.

  2. Soil contaminations in landfill: a case study of the landfill in Czech Republic

    NASA Astrophysics Data System (ADS)

    Adamcová, D.; Vaverková, M. D.; Bartoň, S.; Havlíček, Z.; Břoušková, E.

    2015-10-01

    Phytotoxicity test was determined to assess ecotoxicity of landfill soil. Sinapis alba L. was used as heavy metals bioindicator. Soil samples 1-8, which were taken from the landfill body, edge of the landfill body and its vicinity meet the limits for heavy metals Co, Cd, Pb, and Zn specified in the applicable legislation. Hg and Mn threshold values are not established in legislation, but values have been determined for the needs of the landfill operator. For heavy metals Cr, Cu, and Ni sample 2 exceeded the threshold values, which attained the highest values of all the samples tested for Cr, Cu and Ni. For Cr and Ni the values were several times higher than values of the other samples. The second highest values for Cr, Cu, and Ni showed sample 6 and 7. Both samples exceeded the set limits. An increase in plant biomass was observed in plants growing on plates with soil samples, but no changes in appearance, slow growth or necrotic lesions appeared. Ecotoxicity tests show that tested soils (concentration of 50 %) collected from the landfill body, edge of the landfill body and its vicinity reach high percentage values of germination capacity of seeds of Sinapis alba L. (101-137 %). At a concentration of 25 %, tested soil samples exhibit lower values of germination capacity; in particular samples 3 to 8, yet the seed germination capacity in all 8 samples of tested soils range between 86 and 137 %.

  3. Stimulation of methane oxidation potential and effects on vegetation growth by bottom ash addition in a landfill final evapotranspiration cover.

    PubMed

    Kim, Gil Won; Ho, Adrian; Kim, Pil Joo; Kim, Sang Yoon

    2016-09-01

    The landfilling of municipal solid waste is a significant source of atmospheric methane (CH4), contributing up to 20% of total anthropogenic CH4 emissions. The evapotranspiration (ET) cover system, an alternative final cover system in waste landfills, has been considered to be a promising way to mitigate CH4 emissions, as well as to prevent water infiltration using vegetation on landfill cover soils. In our previous studies, bottom ash from coal-fired power plants was selected among several industrial residues (blast furnace slag, bottom ash, construction waste, steel manufacture slag, stone powder sludge, and waste gypsum) as the best additive for ET cover systems, with the highest mechanical performance achieved for a 35% (wtwt(-1)) bottom ash content in soil. In this study, to evaluate the field applicability of bottom ash mixed soil as ET cover, four sets of lysimeters (height 1.2m×width 2m×length 6m) were constructed in 2007, and four different treatments were installed: (i) soil+bottom ash (35% wtwt(-1)) (SB); (ii) soil+compost (2% wtwt(-1), approximately corresponding to 40Mgha(-1) in arable field scale) (SC); (iii) soil+bottom ash+compost (SBC); and (iv) soil only as the control (S). The effects of bottom ash mixing in ET cover soil on CH4 oxidation potential and vegetation growth were evaluated in a pilot ET cover system in the 5th year after installation by pilot experiments using the treatments. Our results showed that soil properties were significantly improved by bottom ash mixing, resulting in higher plant growth. Bottom ash addition significantly increased the CH4 oxidation potential of the ET cover soil, mainly due to improved organic matter and available copper concentration, enhancing methanotrophic abundances in soil amended with bottom ash. Conclusively, bottom ash could be a good alternative as a soil additive in the ET cover system to improve vegetation growth and mitigate CH4 emission impact in the waste landfill system. PMID:27067424

  4. Gas permeability of biochar-amended clay: potential alternative landfill final cover material.

    PubMed

    Wong, James Tsz Fung; Chen, Zhongkui; Ng, Charles Wang Wai; Wong, Ming Hung

    2016-04-01

    Compacted biochar-amended clay (BAC) has been proposed as an alternative landfill final cover material in this study. Biochar has long been proposed to promote crop growth, mitigate odor emission, and promote methane oxidation in field soils. However, previous studies showed that soil-gas permeability was increased upon biochar application, which will promote landfill gas emission. The objective of the present study is to investigate the possibility of using compacted BAC as an alternative material in landfill final cover by evaluating its gas permeability. BAC samples were prepared by mixing 425-μm-sieved peanut shell biochar with kaolin clay in different ratios (0, 5, 10, and 15 %, w/w) and compacting at different degrees of compactions (DOC) (80, 85, and 90 %) with an optimum water content of 35 %. The gas permeability of the BACs was measured by flexible wall gas permeameter and the microstructure of the BACs was analyzed by SEM with energy-dispersive x-ray spectroscopy (EDX). The results show that the effects of biochar content on BAC gas permeability is highly dependent on the DOC. At high DOC (90 %), the gas permeability of BAC decreases with increasing biochar content due to the combined effect of the clay aggregation and the inhibition of biochar in the gas flow. However, at low DOC (80 %), biochar incorporation has no effects on gas permeability because it no longer acts as a filling material to the retard gas flow. The results from the present study imply that compacted BAC can be used as an alternative final cover material with decreased gas permeability when compared with clay. PMID:26092359

  5. Successive development of soil ecosystems at abandoned coal-ash landfills.

    PubMed

    Pen-Mouratov, Stanislav; Shukurov, Nosir; Yu, Jun; Rakhmonkulova, Shakhnoza; Kodirov, Obidjon; Barness, Gineta; Kersten, Michael; Steinberger, Yosef

    2014-07-01

    The main goal of the present study was to determine the effect of the native vegetation on the successive development of the soil ecosystem at abandoned coal-ash landfills of the Angren coal-fired power plant in Uzbekistan. Two different landfills (one not in use for 3 years, termed newer, and the other not in use for 10 years, termed older) with different degrees of vegetation cover were chosen to assess the time and vegetation effects on soil biota and habitat development. The soil biotic structure, including soil microorganisms and soil free-living nematode communities, was investigated both at open plots and under different native plants at the coal-ash landfill area. The observed soil microorganisms were found to be the most important component of the observed ecosystems. Total abundance, biomass, species, trophic and sexual diversity of soil free-living nematodes, along with fungi and organic-matter content, were found to be correlated with trace metals. The nematode trophic and species abundance and diversity increased from the newer toward the older coal-ash landfills. The sex ratio of the nematode communities was found to be dependent on the environmental conditions of the study area, with the males being the most sensitive nematode group. All applied ecological indices confirmed that open landfill plots distant from plants are the most unfavorable areas for soil biota. In that respect, the native plants Alhagi maurorum Desv. and Tamarix sp. were found to be important environmental components for the natural remediation of a soil ecosystem in the coal-ash landfill area. PMID:24676936

  6. Methane oxidation potential of boreal landfill cover materials: The governing factors and enhancement by nutrient manipulation.

    PubMed

    Maanoja, Susanna T; Rintala, Jukka A

    2015-12-01

    Methanotrophs inhabiting landfill covers are in a crucial role in mitigating CH4 emissions, but the characteristics of the cover material or ambient temperature do not always enable the maximal CH4 oxidation potential (MOP). This study aimed at identifying the factors governing MOPs of different materials used for constructing biocovers and other cover structures. We also tested whether the activity of methanotrophs could be enhanced at cold temperature (4 and 12°C) by improving the nutrient content (NO3(-), PO4(3-), trace elements) of the cover material. Compost samples from biocovers designed to support CH4 oxidation were exhibiting the highest MOPs (4.16 μmol CH4 g dw(-1) h(-1)), but also the soil samples collected from other cover structures were oxidising CH4 (0.41 μmol CH4 g dw(-1) h(-1)). The best predictors for the MOPs were the NO3(-) content and activity of heterotrophic bacteria at 72.8%, which were higher in the compost samples than in the soil samples. The depletion of NO3(-) from the landfill cover material limiting the activity of methanotrophs could not be confirmed by the nutrient manipulation assay at 4°C as the addition of nitrogen decreased the MOPs from 0.090 μmol CH4 g dw(-1) h(-1) to <0.085 μmol CH4 g dw(-1) h(-1). At 12°C, all nutrient additions reduced the MOPs. The inhibition was believed to result from high ionic concentration caused by nutrient addition. At 4°C, the addition of trace elements increased the MOPs (>0.096 μmol CH4 g dw(-1)h(-1)) suggesting that this was attributable to stimulation of the enzymatic activity of the psychrotolerant methanotrophs. PMID:26298483

  7. Accelerated carbonation of steel slags in a landfill cover construction

    SciTech Connect

    Diener, S.; Andreas, L.; Herrmann, I.; Ecke, H.; Lagerkvist, A.

    2010-01-15

    Steel slags from high-alloyed tool steel production were used in a full scale cover construction of a municipal solid waste (MSW) landfill. In order to study the long-term stability of the steel slags within the final cover, a laboratory experiment was performed. The effect on the ageing process, due to i.e. carbonation, exerted by five different factors resembling both the material characteristics and the environmental conditions is investigated. Leaching behaviour, acid neutralization capacity and mineralogy (evaluated by means of X-ray diffraction, XRD, and thermogravimetry/differential thermal analysis, TG/DTA) are tested after different periods of ageing under different conditions. Samples aged for 3 and 10 months were evaluated in this paper. Multivariate data analysis was used for data evaluation. The results indicate that among the investigated factors, ageing time and carbon dioxide content of the atmosphere were able to exert the most relevant effect. However, further investigations are required in order to clarify the role of the temperature.

  8. Design of top covers supporting aerobic in situ stabilization of old landfills - An experimental simulation in lysimeters

    SciTech Connect

    Hrad, Marlies; Huber-Humer, Marion; Wimmer, Bernhard; Reichenauer, Thomas G.

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Tested engineered covers as surrogate to gas extraction during and after in situ aeration. Black-Right-Pointing-Pointer Examined how covers influence gas emissions, water balance and leachate generation. Black-Right-Pointing-Pointer Investigated effect of top covers on air-distribution in waste mass during aeration. Black-Right-Pointing-Pointer We suggest criteria and cover design to meet the demands during and after aeration. Black-Right-Pointing-Pointer Such cover systems may offer greenhouse gas emission reduction also after active aeration. - Abstract: Landfill aeration by means of low pressure air injection is a promising tool to reduce long term emissions from organic waste fractions through accelerated biological stabilization. Top covers that enhance methane oxidation could provide a simple and economic way to mitigate residual greenhouse gas emissions from in situ aerated landfills, and may replace off-gas extraction and treatment, particularly at smaller and older sites. In this respect the installation of a landfill cover system adjusted to the forced-aerated landfill body is of great significance. Investigations into large scale lysimeters (2 Multiplication-Sign 2 Multiplication-Sign 3 m) under field conditions have been carried out using different top covers including compost materials and natural soils as a surrogate to gas extraction during active low pressure aeration. In the present study, the emission behaviour as well as the water balance performance of the lysimeters has been investigated, both prior to and during the first months of in situ aeration. Results reveal that mature sewage sludge compost (SSC) placed in one lysimeter exhibits in principle optimal ambient conditions for methanotrophic bacteria to enhance methane oxidation. Under laboratory conditions the mature compost mitigated CH{sub 4} loadings up to 300 l CH{sub 4}/m{sup 2} d. In addition, the compost material provided high air permeability

  9. Improved field methods to quantify methane oxidation in landfill cover materials using stable carbon isotopes.

    PubMed

    Chanton, J P; Powelson, D K; Abichou, T; Hater, G

    2008-02-01

    Stable carbon isotopes provide a robust approach toward quantification of methanotrophic activity in landfill covers. The field method often applied to date has compared the delta13C of emitted to anaerobic zone CH4. Recent laboratory mass balance studies have indicated thatthis approach tends to underestimate CH4 oxidation. Therefore, we examined the CH4-delta13C at various soil depths in field settings and compared these values to emitted CH4. At 5-10 cm depth, we observed the most enrichment in CH4-delta13C (-46.0 to -32.1 per thousand). Emitted CH4-delta13C was more negative, ranging from -56.5 to -43.0 per thousand. The decrease in CH4-delta13C values from the shallow subsurface to the surface is the result of processes that result in selective emission of 12CH4 and selective retention of 13CH4 within the soil. Seasonal percent oxidation was calculated at seven sites representing four cover materials. Probe samples averaged greater (21 +/- 2%, p < 0.001, n = 7) oxidation than emitted CH4 data. We argue that calculations of fraction oxidized based on soil derived CH4 should yield upper limit values. When considered with emitted CH4 values, this combined approach will more realistically bracket the actual oxidation value. Following this guideline, we found the percent oxidation to be 23 +/- 3% and 38 +/- 16% for four soil and three compost covers, respectively. PMID:18323085

  10. Field Performance of A Compacted Clay Landfill Final cover At A Humid Site

    SciTech Connect

    Albright, William H.; Benson, Craig H.; Gee, Glendon W.; Abichou, Tarek; Mcdonald, Eric V.; Tyler, Scott W.; Rock, Steven

    2006-11-01

    A study was conducted in southern Georgia, USA to evaluate how the hydraulic properties of the compacted clay barrier layer in a landfill final cover changed over a 4-yr service life. The cover was part of a test section constructed in a large drainage lysimeter that allowed CE Database subject headings: landfill, hydrogeology, compacted soils, lysimeters, desiccation continuous monitoring of the water balance. Patterns in the drainage (i.e., flow from the bottom of the cover) record suggest that preferential flow paths developed in the clay barrier soon after construction, apparently in response to desiccation cracking. After four years, the clay barrier was excavated and examined for changes in soil structure and hydraulic conductivity. Tests were conducted in situ with a sealed double-ring infiltrometer and two-stage borehole permeameters and in the laboratory on hand-carved blocks taken during construction and after four years of service. The in situ and laboratory tests indicated that the hydraulic conductivity increased approximately three orders of magnitude (from ? 10-7 to ? 10-4 cm s-1) during the service life. A dye tracer test and soil structure analysis showed that extensive cracking and root development occurred throughout the entire depth of the barrier layer. Laboratory tests on undisturbed specimens of the clay barrier indicated that the hydraulic conductivity of damaged clay barriers can be under-estimated significantly if small specimens (e.g., tube samples) are used for hydraulic conductivity assessment. The findings also indicate that clay barriers must be protected from desiccation and root intrusion if they are expected to function as intended, even at sites in warm, humid locations.

  11. Use of a biologically active cover to reduce landfill methane emissions and enhance methane oxidation.

    PubMed

    Stern, Jennifer C; Chanton, Jeff; Abichou, Tarek; Powelson, David; Yuan, Lei; Escoriza, Sharon; Bogner, Jean

    2007-01-01

    Biologically-active landfill cover soils (biocovers) that serve to minimize CH4 emissions by optimizing CH4 oxidation were investigated at a landfill in Florida, USA. The biocover consisted of 50 cm pre-composted yard or garden waste placed over a 10-15 cm gas distribution layer (crushed glass) over a 40-100 cm interim cover. The biocover cells reduced CH4 emissions by a factor of 10 and doubled the percentage of CH4 oxidation relative to control cells. The thickness and moisture-holding capacity of the biocover resulted in increased retention times for transported CH4. This increased retention of CH4 in the biocover resulted in a higher fraction oxidized. Overall rates between the two covers were similar, about 2g CH4 m(-2)d(-1), but because CH4 entered the biocover from below at a slower rate relative to the soil cover, a higher percentage was oxidized. In part, methane oxidation controlled the net flux of CH4 to the atmosphere. The biocover cells became more effective than the control sites in oxidizing CH4 3 months after their initial placement: the mean percent oxidation for the biocover cells was 41% compared to 14% for the control cells (p<0.001). Following the initial 3 months, we also observed 29 (27%) negative CH4 fluxes and 27 (25%) zero fluxes in the biocover cells but only 6 (6%) negative fluxes and 22 (21%) zero fluxes for the control cells. Negative fluxes indicate uptake of atmospheric CH4. If the zero and negative fluxes are assumed to represent 100% oxidation, then the mean percent oxidation for the biocover and control cells, respectively, for the same period would increase to 64% and 30%. PMID:17005386

  12. Reevaluating the role of soil layers in landfill construction

    SciTech Connect

    Roberts, M.; Larky, A.

    1996-05-01

    While most Subtitle D landfills are required to use a clay soil layer to protect the bottom liner or leachate collection system, many have begun experimenting- and succeeding-with use of ground tires, wood chips, sewage sludge, compost and other materials in place of the soil.

  13. Design of top covers supporting aerobic in situ stabilization of old landfills--an experimental simulation in lysimeters.

    PubMed

    Hrad, Marlies; Huber-Humer, Marion; Wimmer, Bernhard; Reichenauer, Thomas G

    2012-12-01

    Landfill aeration by means of low pressure air injection is a promising tool to reduce long term emissions from organic waste fractions through accelerated biological stabilization. Top covers that enhance methane oxidation could provide a simple and economic way to mitigate residual greenhouse gas emissions from in situ aerated landfills, and may replace off-gas extraction and treatment, particularly at smaller and older sites. In this respect the installation of a landfill cover system adjusted to the forced-aerated landfill body is of great significance. Investigations into large scale lysimeters (2 × 2 × 3m) under field conditions have been carried out using different top covers including compost materials and natural soils as a surrogate to gas extraction during active low pressure aeration. In the present study, the emission behaviour as well as the water balance performance of the lysimeters has been investigated, both prior to and during the first months of in situ aeration. Results reveal that mature sewage sludge compost (SSC) placed in one lysimeter exhibits in principle optimal ambient conditions for methanotrophic bacteria to enhance methane oxidation. Under laboratory conditions the mature compost mitigated CH(4) loadings up to 300 lCH(4)/m(2)d. In addition, the compost material provided high air permeability even at 100% water holding capacity (WHC). In contrast, the more cohesive, mineral soil cover was expected to cause a notably uniform distribution of the injected air within the waste layer. Laboratory results also revealed sufficient air permeability of the soil materials (TS-F and SS-Z) placed in lysimeter C. However, at higher compaction density SS-Z became impermeable at 100% WHC. Methane emissions from the reference lysimeter with the smaller substrate cover (12-52 g CH(4)/m(2)d) were significantly higher than fluxes from the other lysimeters (0-19 g CH(4)/m(2)d) during in situ aeration. Regarding water balance, lysimeters covered with

  14. Prediction of long-term erosion from landfill covers in the southwest

    SciTech Connect

    Anderson, C.E.; Stormont, J.C.

    1997-12-31

    Erosion is a primary stressor of landfill covers, especially for climates with high intensity storms and low native plant density. Rills and gullies formed by discrete events can damage barrier layers and induce failure. Geomorphologic, empirical and physical modeling procedures are available to provide estimates of surface erosion, but numerical modeling requires accurate representation of the severe rainfall events that generate erosion. The National Weather Service precipitation frequency data and estimates of 5, 10, 15, 30 and 60-minute intensity can be statistically combined in a numerical model to obtain long-term erosion estimates. Physically based numerical models using the KINEROS and AHYMO programs have been utilized to predict the erosion from a southwestern landfill or waste containment site with 0.03, 0.05 and 0.08 meter per meter surface slopes. Results of AHYMO modeling were within 15 percent of average annual values computed with the empirical Universal Soil Loss Equation. However, the estimation of rill and gully formation that primarily degrades cover systems requires quantifying single events. For Southwestern conditions, a single 10-year storm can produce erosion quantifies equal to three times the average annual erosion and a 100-year storm can produce five times the average annual erosion.

  15. Observations on the methane oxidation capacity of landfill soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field data and two independent models indicate that landfill cover methane (CH4) oxidation should not be considered as a constant 10% or any other single value. Percent oxidation is a decreasing exponential function of the total methane flux rate into the cover and is also dependent on climate and c...

  16. USE OF ALTERNATIVE MATERIALS FOR DAILY COVER AT MUNICIPAL SOLID WASTE LANDFILLS

    EPA Science Inventory

    The current (ca. 1992) applicability of alternative materials as daily cover at landfills was assessed from an operational, performance, environmental, and economic perspective. he types of products and materials considered included commercially available foams, spray-ons and geo...

  17. Alternative Landfill Cover and Monitoring Systems for Landfills in Arid Environments

    SciTech Connect

    S. E. Rawlinson

    2002-09-01

    In December 2000, a performance monitoring facility was constructed adjacent to the mixed waste disposal unit U-3ax/bl at the Area 3 Radioactive Waste Management Site at the Nevada Test Site. This facility consists of eight drainage lysimeters measuring 10 feet in diameter, 8 feet deep, and backfilled with native soil. The lysimeters have three different surface treatments: two were left bare, two were revegetated with native species, and two were allowed to revegetate with invader species (two are reserved for future studies). The lysimeters are instrumented with an array of soil water content and soil water potential sensors and have sealed bottoms so that any drainage can be measured. All sensors are working properly and indicate that the bare lysimeters are the wettest, as expected. The vegetated lysimeters, both seeded and those allowed to revegetate with invader species, are significantly drier than the bare cover treatments. No drainage has occurred in any of the lysimeters. The Accelerated Site Technology Deployment program under the U.S. Department of Energy's Office of Science and Technology provided the funding for this project with the objective of reducing the uncertainty associated with the performance of monolayer-evapotranspiration waste covers in arid regions such as the one deployed at U-3ax/bl.

  18. Deployment of an alternative cover and final closure of the Mixed Waste Landfill, Sandia National Laboratories, Albuquerque, New Mexico.

    SciTech Connect

    Peace, Gerald L.; Goering, Timothy James; McVey, Michael David (GRAM, Inc., Albuquerque, NM); Borns, David James

    2003-06-01

    An alternative cover design consisting of a monolithic layer of native soil is proposed as the closure path for the Mixed Waste Landfill at Sandia National Laboratories, New Mexico. The proposed design would rely upon soil thickness and evapotranspiration to provide long-term performance and stability, and would be inexpensive to build and maintain. The proposed design is a 3-ft-thick, vegetated soil cover. The alternative cover meets the intent of RCRA Subtitle C regulations in that: (a) water migration through the cover is minimized; (b) maintenance is minimized by using a monolithic soil layer; (c) cover erosion is minimized by using erosion control measures; (d) subsidence is accommodated by using a ''soft'' design; and (e) the permeability of the cover is less than or equal to that of natural subsurface soil present. Performance of the proposed cover is integrated with natural site conditions, producing a ''system performance'' that will ensure that the cover is protective of human health and the environment. Natural site conditions that will produce a system performance include: (a) extremely low precipitation and high potential evapotranspiration; (b) negligible recharge to groundwater; (c) an extensive vadose zone; (d) groundwater approximately 500 ft below the surface; and (e) a versatile, native flora that will persist indefinitely as a climax ecological community with little or no maintenance.

  19. Two-year performance by evapotranspiration covers for municipal solid waste landfills in northwest Ohio.

    PubMed

    Barnswell, Kristopher D; Dwyer, Daryl F

    2012-12-01

    Evapotranspiration (ET) covers have gained interest as an alternative to conventional covers for the closure of municipal solid waste (MSW) landfills because they are less costly to construct and are expected to have a longer service life. Whereas ET covers have gained acceptance in arid and semi-arid regions (defined by a precipitation (P) to potential evapotranspiration (PET) ratio less than 0.75) by meeting performance standards (e.g. rate of percolation), it remains unclear whether they are suitable for humid regions (P:PET greater than 0.75). The goal of this project is to extend their application to northwest Ohio (P:PET equals 1.29) by designing covers that produce a rate of percolation less than 32 cm yr(-1), the maximum acceptable rate by the Ohio Environmental Protection Agency (OEPA). Test ET covers were constructed in drainage lysimeters (1.52 m diameter, 1.52 m depth) using dredged sediment amended with organic material and consisted of immature (I, plants seeded onto soil) or mature (M, plants transferred from a restored tall-grass prairie) plant mixtures. The water balance for the ET covers was monitored from June 2009 to June 2011, which included measured precipitation and percolation, and estimated soil water storage and evapotranspiration. Precipitation was applied at a rate of 94 cm yr(-1) in the first year and at rate of 69 cm yr(-1) in the second year. During the first year, covers with the M plant mixture produced noticeably less percolation (4 cm) than covers with the I plant mixture (17 cm). However, during the second year, covers with the M plant mixture produced considerably more percolation (10 cm) than covers with the I plant mixture (3 cm). This is likely due to a decrease in the aboveground biomass for the M plant mixture from year 1 (1008 g m(-2)) to year 2 (794 g m(-2)) and an increase for the I plant mixture from year 1 (644 g m(-2)) to year 2 (1314 gm(-2)). Over the 2-year period, the mean annual rates of percolation for the covers

  20. Assessing the environmental impact of ashes used in a landfill cover construction.

    PubMed

    Travar, I; Lidelöw, S; Andreas, L; Tham, G; Lagerkvist, A

    2009-04-01

    Large amounts of construction materials will be needed in Europe in anticipation for capping landfills that will be closed due to the tightening up of landfill legislation. This study was conducted to assess the potential environmental impacts of using refuse derived fuel (RDF) and municipal solid waste incineration (MSWI) ashes as substitutes for natural materials in landfill cover designs. The leaching of substances from a full-scale landfill cover test area built with different fly and bottom ashes was evaluated based on laboratory tests and field monitoring. The water that drained off above the liner (drainage) and the water that percolated through the liner into the landfill (leachate) were contaminated with Cl(-), nitrogen and several trace elements (e.g., As, Cu, Mo, Ni and Se). The drainage from layers containing ash will probably require pre-treatment before discharge. The leachate quality from the ash cover is expected to have a minor influence on overall landfill leachate quality because the amounts generated from the ash covers were low, <3-30l (m(2)yr)(-1). Geochemical modelling indicated that precipitation of clay minerals and other secondary compounds in the ash liner was possible within 3 years after construction, which could contribute to the retention of trace elements in the liner in the long term. Hence, from an environmental view point, the placement of ashes in layers above the liner is more critical than within the liner. PMID:19081235

  1. Use of the time domain reflectrometry in hydraulic studies of multilayered landfill covers for closure of waste landfills at Los Alamos, New Mexico

    SciTech Connect

    Nyhan, J.W.; Schofield, T.G.; Martin, C.E.

    1994-04-01

    The Los Alamos National Laboratory examined water balance relationships for four different landfill cover designs containing hydraulic and capillary engineered barriers. Seepage is being evaluated as a function of slope length for each plot, as well as interflow, runoff, and precipitation, using an automated water flow datalogging system that routinely collects hourly data. Soil water content within these 16 field plots has been routinely monitored four times a day since November 1991 using time domain reflectrometry techniques with an automated and multiplexed measurement system. Volumetric water content is measured with a pair of 60-cm-long waveguides at each of 212 locations. One set of waveguides was emplaced vertically in four locations in every soil layer to determine soil water inventory in each field plot. A second set of waveguides was emplaced horizontally in several soil layers to provide a more detailed picture of soil water dynamics close to soil layer interfaces. Field data is presented showing pulses of soil water moving through the soil and engineered barriers with high temporal and spatial resolution.

  2. Steel slag used in landfill cover liners: laboratory and field tests.

    PubMed

    Herrmann, Inga; Andreas, Lale; Diener, Silvia; Lind, Lotta

    2010-12-01

    Stricter rules for landfilling within the EU have led to the closure of many landfills and a need for large amounts of cover liner materials. Therefore, the potential utilization of mixtures of electric arc furnace slag (EAFS) and ladle slag (LS), which are currently deposited in landfills, as a material for use as landfill liner was investigated. Laboratory analyses showed the mixtures to have similar compression strength to that of high-strength concrete and low hydraulic conductivity (< 10(-11) m s(-1) in some cases). However, both their hydraulic conductivity and compaction properties were strongly affected by the time between adding water to the mixtures and compacting them (tests showed that a delay of 24 h can lead to an increase in hydraulic conductivity, so it should be compacted as soon as possible after mixing the material with water). In addition, the performance of a cover liner constructed using EAFS and LS was studied in a 2-year field trial on a landfill for municipal solid waste, in which the average amount of leachate collected from ten lysimeters was only 27 L m(-2) year(-1), easily meeting Swedish criteria for the permeability of covers on non-hazardous waste landfills (≤ 50 L m(-2) year(-1)). Thus, the material seems to have promising potential for use in barrier constructions. PMID:20421245

  3. Toxicity Assessment of Contaminated Soils of Solid Domestic Waste Landfill

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  4. A RULE-BASED SYSTEM FOR EVALUATING FINAL COVERS FOR HAZARDOUS WASTE LANDFILLS

    EPA Science Inventory

    This chapter examines how rules are used as a knowledge representation formalism in the domain of hazardous waste management. A specific example from this domain involves performance evaluation of final covers used to close hazardous waste landfills. Final cover design and associ...

  5. Field Performance Of A Compacted Clay Landfill Final Cover At A Humid Site

    EPA Science Inventory

    A study was conducted in southern Georgia, USA, to evalaute how the hydraulic properties of the compacted clay barrier layer in a final landfill cover changed over a 4-year service life. The cover was part of a test section constructed in a large drainage lysimeter that allowed ...

  6. Landfill cover revegetation using organic amendments and cobble mulch in the arid southwest

    SciTech Connect

    AGUILAR,RICHARD; DWYER,STEPHEN F.; REAVIS,BRUCE A.; NEWMAN,GRETCHEN CARR; LOFTIN,SAMUEL R.

    2000-02-01

    production in the irrigated control plots over that produced in the non-irrigated control plots. This surprising result was probably due to the cumulative effects of other factors that influenced the initial establishment and production of plants in the plots (e.g., plant species competition, seed germination delay times, differences in nutrient release and availability). Variation within individual plots, and among the three replicate plots associated with each treatment, rendered many of the recorded differences in vegetation establishment and production statistically insignificant. However, after two complete growing seasons the highest total plant foliar cover and the greatest biomass production and plant species diversity occurred in the cobble-mulched plots. These results suggest that cobble-mulch may be the desired amendment in re-vegetated arid landfill covers if the principal objectives are to quickly establish vegetation cover, stabilize the site from erosion, and increase water usage by plants, thereby reducing the potential for leaching and contaminant movement from the landfill's waste-bearing zone.

  7. Landfill leachate clogging of geotextile (and soil) filters

    SciTech Connect

    Koerner, R.M.; Koerner, G.R.

    1991-07-01

    The primary leachate collection system of most solid waste landfills contains a filter layer which has historically been a granular soil. Recently, however, various types of geotextile filters have been used to replace the natural soil filters. A project using six different landfill leachates and aimed at investigating the functioning of different geotextile filters is the focus of this 36 month long study. The initial 12 months, referred to as Phase 1, investigated flow rates in various filters under aerobic conditions at six different landfill sites using the site-specific leachates. The study inadvertently found that the overlying granular soil clogged as much as the geotextile filter that was located downstream. The effects of different types and styles of geotextiles was generally masked by the upstream soil clogging. An important finding in this task was the biodegradation of the geotextiles was not evidenced and was concluded to be a non-issue. The subsequent 24 months of study, referred to as Phase 2(a), led to the development of a vastly improved flow rate monitoring device. In a separate task, referred to as Phase 2(b) and conducted simultaneously with Phase 2(a), biocide treated geosynthetics were utilized at the two sites with the most aggressive leachates. While the biocides may have been effective in killing microorganisms, the remnants were as troublesome as the viable bacteria in creating subsequent clogging.

  8. Empirical gas emission and oxidation measurement at cover soil of dumping site: example from Malaysia.

    PubMed

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

    2013-06-01

    Methane (CH₄) is one of the most relevant greenhouse gases and it has a global warming potential 25 times greater than that of carbon dioxide (CO₂), risking human health and the environment. Microbial CH₄ oxidation in landfill cover soils may constitute a means of controlling CH₄ emissions. The study was intended to quantify CH₄ and CO₂ emissions rates at the Sungai Sedu open dumping landfill during the dry season, characterize their spatial and temporal variations, and measure the CH₄ oxidation associated with the landfill cover soil using a homemade static flux chamber. Concentrations of the gases were analyzed by a Micro-GC CP-4900. Two methods, kriging values and inverse distance weighting (IDW), were found almost identical. The findings of the proposed method show that the ratio of CH₄ to CO₂ emissions was 25.4 %, indicating higher CO₂ emissions than CH₄ emissions. Also, the average CH₄ oxidation in the landfill cover soil was 52.5 %. The CH₄ and CO₂ emissions did not show fixed-pattern temporal variation based on daytime measurements. Statistically, a negative relationship was found between CH₄ emissions and oxidation (R(2) = 0.46). It can be concluded that the variation in the CH₄ oxidation was mainly attributed to the properties of the landfill cover soil. PMID:23054277

  9. Feasibility of biochar application on a landfill final cover-a review on balancing ecology and shallow slope stability.

    PubMed

    Chen, Xun-Wen; Wong, James Tsz-Fung; Ng, Charles Wang-Wai; Wong, Ming-Hung

    2016-04-01

    Due to the increasing concerns on global warming, scarce land for agriculture, and contamination impacts on human health, biochar application is being considered as one of the possible measures for carbon sequestration, promoting higher crop yield and contamination remediation. Significant amount of researches focusing on these three aspects have been conducted during recent years. Biochar as a soil amendment is effective in promoting plant performance and sustainability, by enhancing nutrient bioavailability, contaminants immobilization, and microbial activities. The features of biochar in changing soil physical and biochemical properties are essential in affecting the sustainability of an ecosystem. Most studies showed positive results and considered biochar application as an effective and promising measure for above-mentioned interests. Bio-engineered man-made filled slope and landfill slope increasingly draw the attention of geologists and geotechnical engineers. With increasing number of filled slopes, sustainability, low maintenance, and stability are the major concerns. Biochar as a soil amendment changes the key factors and parameters in ecology (plant development, soil microbial community, nutrient/contaminant cycling, etc.) and slope engineering (soil weight, internal friction angle and cohesion, etc.). This paper reviews the studies on the production, physical and biochemical properties of biochar and suggests the potential areas requiring study in balancing ecology and man-made filled slope and landfill cover engineering. Biochar-amended soil should be considered as a new type of soil in terms of soil mechanics. Biochar performance depends on soil and biochar type which imposes challenges to generalize the research outcomes. Aging process and ecotoxicity studies of biochar are strongly required. PMID:26452652

  10. Two-year performance by evapotranspiration covers for municipal solid waste landfills in northwest Ohio

    SciTech Connect

    Barnswell, Kristopher D.; Dwyer, Daryl F.

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer All ET covers produced rates of percolation less than 32 cm yr{sup -1}, the maximum allowable rate by the Ohio EPA. Black-Right-Pointing-Pointer Dredged sediment provided sufficient water storage and promoted growth by native plant species. Black-Right-Pointing-Pointer Native plant mixtures attained acceptable rates of evapotranspiration throughout the growing season. - Abstract: Evapotranspiration (ET) covers have gained interest as an alternative to conventional covers for the closure of municipal solid waste (MSW) landfills because they are less costly to construct and are expected to have a longer service life. Whereas ET covers have gained acceptance in arid and semi-arid regions (defined by a precipitation (P) to potential evapotranspiration (PET) ratio less than 0.75) by meeting performance standards (e.g. rate of percolation), it remains unclear whether they are suitable for humid regions (P:PET greater than 0.75). The goal of this project is to extend their application to northwest Ohio (P:PET equals 1.29) by designing covers that produce a rate of percolation less than 32 cm yr{sup -1}, the maximum acceptable rate by the Ohio Environmental Protection Agency (OEPA). Test ET covers were constructed in drainage lysimeters (1.52 m diameter, 1.52 m depth) using dredged sediment amended with organic material and consisted of immature (I, plants seeded onto soil) or mature (M, plants transferred from a restored tall-grass prairie) plant mixtures. The water balance for the ET covers was monitored from June 2009 to June 2011, which included measured precipitation and percolation, and estimated soil water storage and evapotranspiration. Precipitation was applied at a rate of 94 cm yr{sup -1} in the first year and at rate of 69 cm yr{sup -1} in the second year. During the first year, covers with the M plant mixture produced noticeably less percolation (4 cm) than covers with the I plant mixture (17 cm). However, during the

  11. Functional Environmental Genomics of a Municipal Landfill Soil

    PubMed Central

    Roelofs, Dick; de Boer, Muriel; Agamennone, Valeria; Bouchier, Pascal; Legler, Juliette; van Straalen, Nico

    2012-01-01

    We investigated the toxicity of soil samples derived from a former municipal landfill site in the South of the Netherlands, where a bioremediation project is running aiming at reusing the site for recreation. Both an organic soil extract and the original soil sample was investigated using the ISO standardized Folsomia soil ecotoxicological testing and gene expression analysis. The 28 day survival/reproduction test revealed that the ecologically more relevant original soil sample was more toxic than the organic soil extract. Microarray analysis showed that the more toxic soil samples induced gene regulatory changes in twice as less genes compared to the soil extract. Consequently gene regulatory changes were highly dependent on sample type, and were to a lesser extent caused by exposure level. An important biological process shared among the two sample types was the detoxification pathway for xenobiotics (biotransformation I, II, and III) suggesting a link between compound type and observed adverse effects. Finally, we were able to retrieve a selected group of genes that show highly significant dose-dependent gene expression and thus were tightly linked with adverse effects on reproduction. Expression of four cytochrome P450 genes showed highest correlation values with reproduction, and maybe promising genetic markers for soil quality. However, a more elaborate set of environmental soil samples is needed to validate the correlation between gene expression induction and adverse phenotypic effects. PMID:22623925

  12. Utilizing a paper sludge barrier layer in a municipal landfill cover in New York

    SciTech Connect

    Moo-Young, H.K. Jr.; Zimmie, T.F.

    1997-12-31

    This paper evaluates the use of paper sludges from the Hudson River Mill as the impermeable barrier in a landfill cover in Corinth, NY. Paper mill sludges are characterized by a high water content, low specific gravity, and high organic content in comparison to clays. In spite of a high water content, the paper sludges from the Hudson River Mill were compacted to a low hydraulic conductivity. The permeability and compressibility of the paper sludges are influenced by the water content and organic content. Although a paper sludge cover system may not initially meet the regulatory requirement for permeability when constructed at the natural water content, the change in void ratio that results from consolidation and dewatering under a low effective stress can reduce the hydraulic conductivity to an acceptable value. The Corinth landfill cover was instrumented to measure the depth of frost penetration into the cover system.

  13. Methane flux and oxidation at two types of intermediate landfill covers.

    PubMed

    Abichou, Tarek; Chanton, Jeffery; Powelson, David; Fleiger, Jill; Escoriaza, Sharon; Lei, Yuan; Stern, Jennifer

    2006-01-01

    Methane emissions were measured on two areas at a Florida (USA) landfill using the static chamber technique. Because existing literature contains few measurements of methane emissions and oxidation in intermediate cover areas, this study focused on field measurement of emissions at 15-cm-thick non-vegetated intermediate cover overlying 1-year-old waste and a 45-cm-thick vegetated intermediate cover overlying 7-year-old waste. The 45 cm thick cover can also simulate non-engineered covers associated with older closed landfills. Oxidation of the emitted methane was evaluated using stable isotope techniques. The arithmetic means of the measured fluxes were 54 and 22 g CH(4) m(-2)d(-1) from the thin cover and the thick cover, respectively. The peak flux was 596 g m(-2)d(-1) for the thin cover and 330 g m(-2)d(-1) for the thick cover. The mean percent oxidation was significantly greater (25%) at the thick cover relative to the thin cover (14%). This difference only partly accounted for the difference in emissions from the two sites. Inverse distance weighing was used to describe the spatial variation of flux emissions from each cover type. The geospatial mean flux was 21.6 g m(-2)d(-1) for the thick intermediate cover and 50.0 g m(-2)d(-1) for the thin intermediate cover. High emission zones in the thick cover were fewer and more isolated, while high emission zones in the thin cover were continuous and covered a larger area. These differences in the emission patterns suggest that different CH(4) mitigation techniques should be applied to the two areas. For the thick intermediate cover, we suggest that effective mitigation of methane emissions could be achieved by placement of individualized compost cells over high emission zones. Emissions from the thin intermediate cover, on the other hand, can be mitigated by placing a compost layer over the entire area. PMID:16426833

  14. Reuse of MSWI bottom ash mixed with natural sodium bentonite as landfill cover material.

    PubMed

    Puma, Sara; Marchese, Franco; Dominijanni, Andrea; Manassero, Mario

    2013-06-01

    The research described in this study had the aim of evaluating the reuse of incinerator slag, mixed with sodium bentonite, for landfill capping system components. A characterization was performed on pure bottom ash (BA) samples from an incinerator in the north of Italy. The results show that the BA samples had appropriate properties as covers. The compacted dry unit weight of the studied BA (16.2 kN m(-3)) was lower than the average value that characterizes most conventional fill materials and this can be considered advantageous for landfill cover systems, since the fill has to be placed on low bearing capacity ground or where long-term settlement is possible. Moreover, direct shear tests showed a friction angle of 43°, corresponding to excellent mechanical characteristics that can be considered an advantage against failure. The hydraulic conductivity tests indicated a steady-state value of 8 × 10(-10) m s(-1) for a mixture characterized by a bentonite content by weight of 10%, which was a factor 10 better than required by Italian legislation on landfill covers. The results from a swell index test indicated that fine bentonite swelled, even when divalent cations were released by the BA. The leaching behaviour of the mixture did not show any contamination issues and was far better than obtained for the pure BA. Thus, the BA-bentonite mixture qualified as a suitable material for landfill cover in Italy. Moreover, owing to the low release of toxic compounds, the proposed cover system would have no effect on the leachate quality in the landfill. PMID:23478909

  15. A water balance study of four landfill cover designs varying in slope for semiarid regions

    SciTech Connect

    Nyhan, J.W.; Schofield, T.G.; Salazar, J.A.

    1997-02-01

    The goal of disposing of radioactive and hazardous waste in shallow landfills is to reduce risk to human health and to the environment by isolating contaminants until they no longer pose a hazard. In order to achieve this, the performance of a landfill cover design without an engineered barrier (Conventional Design) was compared with three designs containing either a hydraulic barrier (EPA Design) or a capillary barrier (Loam and Clay Loam Capillary Barrier Designs). Water balance parameters were measured since 1991 at six-hour intervals for four different landfill cover designs in 1.0- by 10.0-m plots with downhill slopes of 5, 10, 15, and 25%. Whereas runoff generally accounted for only 2-3% of the precipitation losses on these designs, similar values for evapotranspiration ranged from 86% to 91%, with increased evapotranspiration occurring with increases in slope. Consequently, interflow and seepage usually decreased with increasing slope for each landfill cover design. Seepage consisted of up to 10% of the precipitation on the Conventional Design, whereas the hydraulic barrier in the EPA Design effectively controlled seepage at all slopes, and both of the capillary designs worked effectively to eliminate seepage at the higher slopes.

  16. A fully coupled model for water-gas-heat reactive transport with methane oxidation in landfill covers.

    PubMed

    Ng, C W W; Feng, S; Liu, H W

    2015-03-01

    Methane oxidation in landfill covers is a complex process involving water, gas and heat transfer as well as microbial oxidation. The coupled phenomena of microbial oxidation, water, gas, and heat transfer are not fully understood. In this study, a new model is developed that incorporates water-gas-heat coupled reactive transport in unsaturated soil with methane oxidation. Effects of microbial oxidation-generated water and heat are included. The model is calibrated using published data from a laboratory soil column test. Moreover, a series of parametric studies are carried out to investigate the influence of microbial oxidation-generated water and heat, initial water content on methane oxidation efficiency. Computed and measured results of gas concentration and methane oxidation rate are consistent. It is found that the coupling effects between water-gas-heat transfer and methane oxidation are significant. Ignoring microbial oxidation-generated water and heat can result in a significant difference in methane oxidation efficiency by 100%. PMID:25489976

  17. A process-based inventory model for landfill CH4 emissions inclusive of seasonal soil microclimate and CH4 oxidation

    NASA Astrophysics Data System (ADS)

    Spokas, K.; Bogner, J.; Chanton, J.

    2011-12-01

    We have developed and field-validated an annual inventory model for California landfill CH4 emissions that incorporates both site-specific soil properties and soil microclimate modeling coupled to 0.5° scale global climatic models. Based on 1-D diffusion, CALMIM (California Landfill Methane Inventory Model) is a freely available JAVA tool which models a typical annual cycle for CH4 emissions from site-specific daily, intermediate, and final landfill cover designs. Literature over the last decade has emphasized that the major factors controlling emissions in these highly managed soil systems are the presence or absence of engineered gas extraction, gaseous transport rates as affected by the thickness and physical properties of cover soils, and methanotrophic CH4 oxidation in cover materials as a function of seasonal soil microclimate. Moreover, current IPCC national inventory models for landfill CH4 emissions based on theoretical gas generation have high uncertainties and lack comprehensive field validation. This new approach, which is compliant with IPCC "Tier III" criteria, has been field-validated at two California sites (Monterey County; Los Angeles County), with limited field validation at three additional California sites. CALMIM accurately predicts soil temperature and moisture trends with emission predictions within the same order of magnitude as field measurements, indicating an acceptable initial model comparison in the context of published literature on measured CH4 emissions spanning 7 orders of magnitude. In addition to regional defaults for inventory purposes, CALMIM permits user-selectable parameters and boundary conditions for more rigorous site-specific applications where detailed CH4 emissions, meteorological, and soil microclimate data exist.

  18. Assessment of an active dry barrier for a landfill cover system

    SciTech Connect

    Stormont, J.C.; Ankeny, M.D.; Burkhard, M.E.; Tansey, M.K.; Kelsey, J.A.

    1994-03-01

    A dry barrier is a layer of geologic material that is dried by air flow. An active dry barrier system can be designed, installed, and operated as part of a landfill cover system. An active system uses blowers and fans to move air through a high-permeability layer within the cover system. Depending principally on the air-flow rate, it is possible for a dry barrier to remove enough water to substantially reduce the likelihood of water percolating through the cover system. If a material with a relatively great storage capacity, such as processed tuff, is used as the coarse layer, then the efficiency of the dry barrier will be increased.

  19. Methane flux and oxidation at two types of intermediate landfill covers

    SciTech Connect

    Abichou, Tarek . E-mail: abichou@eng.fsu.edu; Chanton, Jeffery; Powelson, David; Fleiger, Jill; Escoriaza, Sharon; Lei, Yuan; Stern, Jennifer

    2006-07-01

    Methane emissions were measured on two areas at a Florida (USA) landfill using the static chamber technique. Because existing literature contains few measurements of methane emissions and oxidation in intermediate cover areas, this study focused on field measurement of emissions at 15-cm-thick non-vegetated intermediate cover overlying 1-year-old waste and a 45-cm-thick vegetated intermediate cover overlying 7-year-old waste. The 45 cm thick cover can also simulate non-engineered covers associated with older closed landfills. Oxidation of the emitted methane was evaluated using stable isotope techniques. The arithmetic means of the measured fluxes were 54 and 22 g CH{sub 4} m{sup -2} d{sup -1} from the thin cover and the thick cover, respectively. The peak flux was 596 g m{sup -2} d{sup -1} for the thin cover and 330 g m{sup -2} d{sup -1} for the thick cover. The mean percent oxidation was significantly greater (25%) at the thick cover relative to the thin cover (14%). This difference only partly accounted for the difference in emissions from the two sites. Inverse distance weighing was used to describe the spatial variation of flux emissions from each cover type. The geospatial mean flux was 21.6 g m{sup -2} d{sup -1} for the thick intermediate cover and 50.0 g m{sup -2} d{sup -1} for the thin intermediate cover. High emission zones in the thick cover were fewer and more isolated, while high emission zones in the thin cover were continuous and covered a larger area. These differences in the emission patterns suggest that different CH{sub 4} mitigation techniques should be applied to the two areas. For the thick intermediate cover, we suggest that effective mitigation of methane emissions could be achieved by placement of individualized compost cells over high emission zones. Emissions from the thin intermediate cover, on the other hand, can be mitigated by placing a compost layer over the entire area.

  20. CHEMICAL AND PHYSICAL EFFECTS OF MUNICIPAL LANDFILLS ON UNDERLYING SOILS AND GROUNDWATER

    EPA Science Inventory

    Three municipal landfill sites in the eastern and central United States were studied to determine the effects of the disposal facilities on surrounding soils and groundwater. Borings were made up the groundwater gradient, down the groundwater gradient and through the landfill. So...

  1. PREDICTION/MITIGATION OF SUBSIDENCE DAMAGE TO HAZARDOUS WASTE LANDFILL COVERS

    EPA Science Inventory

    Characteristics of Resource Conservation and Recovery Act hazardous waste landfills and of landfilled hazardous wastes have been described to permit development of models and other analytical techniques for predicting, reducing, and preventing landfill settlement and related cove...

  2. Effects of substrate induced respiration on the stability of bottom ash in landfill cover environment.

    PubMed

    Ilyas, A; Lovat, E; Persson, K M

    2014-12-01

    The municipal solid waste incineration bottom ash is being increasingly used to construct landfill covers in Sweden. In post-closure, owing to increased cover infiltration, the percolating water can add external organic matter to bottom ash. The addition and subsequent degradation of this external organic matter can affect metal mobility through complexation and change in redox conditions. However, the impacts of such external organic matter addition on bottom ash stability have not been fully evaluated yet. Therefore, the objective of this study was to evaluate the impact of external organic matter on bottom ash respiration and metal leaching. The samples of weathered bottom ash were mixed with oven dried and digested wastewater sludge (1%-5% by weight). The aerobic respiration activity (AT4), as well as the leaching of metals, was tested with the help of respiration and batch leaching tests. The respiration and heavy metal leaching increased linearly with the external organic matter addition. Based on the results, it was concluded that the external organic matter addition would negatively affect the quality of landfill cover drainage. PMID:25395160

  3. Regulatory guidance on soil cover systems

    SciTech Connect

    Kane, J.D.

    1991-12-31

    The US Nuclear Regulatory Commission (NRC) in September 1991, completed revisions to 14 sections of the Standard Review Plan (SRP) for the Review of a License Application for a Low-Level Radioactive Waste Disposal Facility. The major purposes of the SRP are to ensure the quality and uniformity of the NRC staff`s safety reviews, and to present a well-defined base from which to evaluate the acceptability of information and data provided in the Safety Analysis Report (SAR) portion of the license application. SRP 3.2, entitled, Design Considerations for Normal and Abnormal/Accident Conditions, was one of the sections that was revised by the NRC staff. This revision was completed to provide additional regulatory guidance on the important considerations that need to be addressed for the proper design and construction of soil cover systems that are to be placed over the LLW. The cover system over the waste is acknowledged to be one of the most important engineered barriers for the long-term stable performance of the disposal facility. The guidance in revised SRP 3.2 summarizes the previous efforts and recommendations of the US Army Corps of Engineers (COE), and a peer review panel on the placement of soil cover systems. NRC published these efforts in NUREG/CR-5432. The discussions in this paper highlight selected recommendations on soil cover issues that the NRC staff considers important for ensuring the safe, long-term performance of the soil cover systems. The development phases to be discussed include: (1) cover design; (2) cover material selection; (3) laboratory and field testing; (4) field placement control and acceptance; and (5) penetrations through the constructed covers.

  4. A Water Balance Study of Four Landfill Cover Designs at Material Disposal Area B in Los Alamos, New Mexico

    SciTech Connect

    David D. Breshears; Fairley J. Barnes; John W. Nyhan; Johnny A. Salazar

    1998-09-01

    The goal of disposing of low-level radioactive and hazardous waste in shallow landfills is to reduce risk to human health and the environment by isolating contaminants until they no longer pose an unacceptable hazard. In order to achieve this, the Department of Energy Environmental Restoration Program is comparing the performance of several different surface covers at Material Disposal Area (MDA) B in Los Alamos. Two conventional landfill were compared with an improved cover designed to minimize plant and animal intrusion and to minimize water infiltration into the underlying wastes. The conventional covers varied in depth and both conventional and improved designs had different combinations of vegetation (grass verses shrub) and gravel mulch (no mulch verses mulch). These treatments were applied to each of 12 plots and water balance parameters were measured from March1987 through June 1995. Adding a gravel mulch significantly influenced the plant covered field plots receiving no gravel mulch averaged 21.2% shrub cover, while plots with gravel had a 20% larger percent cover of shrubs. However, the influence of gravel mulch on the grass cover was even larger than the influence on shrub cover, average grass cover on the plots with no gravel was 16.3%, compared with a 42% increase in grass cover due to gravel mulch. These cover relationships are important to reduce runoff on the landfill cover, as shown by a regression model that predicts that as ground cover is increased from 30 to 90%,annual runoff is reduced from 8.8 to 0.98 cm-a nine-fold increase. We also found that decreasing the slope of the landfill cover from 6 to 2% reduced runoff from the landfill cover by 2.7-fold. To minimize the risk of hazardous waste from landfills to humans, runoff and seepage need to be minimized and evapotranspiration maximized on the landfill cover. This has to be accomplished for dry and wet years at MDA B. Seepage consisted of 1.9% and 6.2% of the precipitation in the average and

  5. Steel slags in a landfill top cover--experiences from a full-scale experiment.

    PubMed

    Andreas, L; Diener, S; Lagerkvist, A

    2014-03-01

    A full scale field study has been carried out in order to test and evaluate the use of slags from high-alloy steel production as the construction materials for a final cover of an old municipal landfill. Five test areas were built using different slag mixtures within the barrier layer (liner). The cover consisted of a foundation layer, a liner with a thickness of 0.7 m, a drainage layer of 0.3 m, a protection layer of 1.5 m and a vegetation layer of 0.25 m. The infiltration varied depending on the cover design used, mainly the liner recipe but also over time and was related to seasons and precipitation intensity. The test areas with liners composed of 50% electric arc furnace (EAF) slag and 50% cementitious ladle slag (LS) on a weight basis and with a proper consistence of the protection layer were found to meet the Swedish infiltration criteria of ⩽50 l (m(2)a)(-1) for final covers for landfills for non-hazardous waste: the cumulative infiltration rates to date were 44, 19 and 0.4 l (m(2)a)(-1) for A1, A4 and A5, respectively. Compared to the precipitation, the portion of leachate was always lower after the summer despite high precipitation from June to August. The main reason for this is evapotranspiration but also the fact that the time delay in the leachate formation following a precipitation event has a stronger effect during the shorter summer sampling periods than the long winter periods. Conventional techniques and equipment can be used but close cooperation between all involved partners is crucial in order to achieve the required performance of the cover. This includes planning, method and equipment testing and quality assurance. PMID:24393476

  6. Development of drainage water quality from a landfill cover built with secondary construction materials.

    PubMed

    Travar, Igor; Andreas, Lale; Kumpiene, Jurate; Lagerkvist, Anders

    2015-01-01

    The aim of this study was to evaluate the drainage water quality from a landfill cover built with secondary construction materials (SCM), fly ash (FA), bottom ash (BA) sewage sludge, compost and its changes over time. Column tests, physical simulation models and a full scale field test were conducted. While the laboratory tests showed a clear trend for all studied constituents towards reduced concentrations over time, the concentrations in the field fluctuated considerably. The primary contaminants in the drainage water were Cl(-), N, dissolved organic matter and Cd, Cu, Ni, Zn with initial concentrations one to three orders of magnitude above the discharge values to the local recipient. Using a sludge/FA mixture in the protection layer resulted in less contaminated drainage water compared to a sludge/BA mixture. If the leaching conditions in the landfill cover change from reduced to oxidized, the release of trace elements from ashes is expected to last about one decade longer while the release of N and organic matter from the sludge can be shortened with about two-three decades. The observed concentration levels and their expected development over time require drainage water treatment for at least three to four decades before the water can be discharged directly to the recipient. PMID:25305684

  7. Field note: comparative efficacy of a woody evapotranspiration landfill cover following the removal of aboveground biomass.

    PubMed

    Schnabel, William; Munk, Jens; Byrd, Amanda

    2015-01-01

    Woody vegetation cultivated for moisture management on evapotranspiration (ET) landfill covers could potentially serve a secondary function as a biomass crop. However, research is required to evaluate the extent to which trees could be harvested from ET covers without significantly impacting their moisture management function. This study investigated the drainage through a six-year-old, primarily poplar/cottonwood ET test cover for a period of one year following the harvest of all woody biomass exceeding a height of 30 cm above ground surface. Results were compared to previously reported drainage observed during the years leading up to the coppice event. In the first year following coppice, the ET cover was found to be 93% effective at redirecting moisture during the spring/summer season, and 95% effective during the subsequent fall/winter season. This was slightly lower than the 95% and 100% efficacy observed in the spring/summer and fall/winter seasons, respectively, during the final measured year prior to coppice. However, the post-coppice efficacy was higher than the efficacy observed during the first three years following establishment of the cover. While additional longer-term studies are recommended, this project demonstrated that woody ET covers could potentially produce harvestable biomass while still effectively managing aerial moisture. PMID:25254294

  8. Site Specific Landfill CH4 Emissions: Shortcomings of National GHG Inventory Guidelines and a New Process-Based Approach Linked to Climate and Soil Microclimate

    NASA Astrophysics Data System (ADS)

    Bogner, J. E.; Spokas, K.; Corcoran, M.

    2012-12-01

    Current (2006) IPCC national GHG inventory guidelines for landfill CH4, which estimate CH4 generation from the mass of waste in place, have high uncertainties, cannot be reliably related to measured emissions at specific sites, and lack comprehensive field validation. Moreover, measured landfill CH4 emissions vary over a wide range from >1000 g/m2/d down to negative values (uptake of atmospheric CH4). Literature over the last decade has emphasized that the major factors controlling emissions in these highly managed soil systems are gaseous transport rates as affected by the thickness and physical properties of cover soils, methanotrophic CH4 oxidation in cover materials as a function of seasonal soil microclimate. and the presence or absence of engineered gas extraction. Thus we developed and field validated a new site specific annual inventory model that incorporates specific soil profile properties and soil microclimate modeling coupled to 0.5° scale global climatic models. Based on 1D diffusion, CALMIM (California Landfill Methane Inventory Model) is a freely available JAVA tool which models a typical annual cycle for CH4 emissions from site specific daily, intermediate, and final landfill cover designs. This new approach, which is compliant with IPCC Tier III criteria, was originally field validated at two California sites (Monterey County; Los Angeles County), with limited field validation at three additional California sites. In addition to regional defaults for inventory purposes, CALMIM permits user selectable parameters and boundary conditions for more rigorous site specific applications where detailed CH4 emissions, meteorological, and soil microclimate data exist. We report here on improvements and expanded international field validation for CALMIM 5.2 in collaboration with research groups in the U.S., Europe, Africa, Asia, and Australia.odeled and measured annual cycle of landfill CH4 emissions for Austrian site. Cover consists of 50 cm sand & gravel

  9. Improving the aeration of critical fine-grained landfill top cover material by vegetation to increase the microbial methane oxidation efficiency.

    PubMed

    Bohn, Sonja; Brunke, Paul; Gebert, Julia; Jager, Johannes

    2011-05-01

    The natural methane oxidation potential of methanotrophic bacteria in landfill top covers is a sustainable and inexpensive method to reduce methane emissions to the atmosphere. Basically, the activity of methanotrophic bacteria is limited by the availability of oxygen in the soil. A column study was carried out to determine whether and to what extent vegetation can improve soil aeration and maintain the methane oxidation process. Tested soils were clayey silt and mature compost. The first soil is critical in light of surface crusting due to vertical erosion of an integral part of fine-grained material, blocking pores required for the gas exchange. The second soil, mature compost, is known for its good methane oxidation characteristics, due to high air-filled porosity, favorable water retention capacity and high nutrient supply. The assortment of plants consisted of a grass mixture, Canadian goldenrod and a mixture of leguminous plants. The compost offered an excellent methane oxidation potential of 100% up to a CH(4)-input of 5.6l CH(4)m(-2)h(-1). Whereas the oxidation potential was strongly diminished in the bare control column filled with clayey silt even at low CH(4)-loads. By contrast the planted clayey silt showed an increased methane oxidation potential compared to the bare column. The spreading root system forms secondary macro-pores, and hence amplifies the air diffusivity and sustain the oxygen supply to the methanotrophic bacteria. Water is produced during methane oxidation, causing leachate. Vegetation reduces the leachate by evapotranspiration. Furthermore, leguminous plants support the enrichment of soil with nitrogen compounds and thus improving the methane oxidation process. In conclusion, vegetation is relevant for the increase of oxygen diffusion into the soil and subsequently enhances effective methane oxidation in landfill cover soils. PMID:21169005

  10. Hydraulic conductivity of fly ash-sewage sludge mixes for use in landfill cover liners.

    PubMed

    Herrmann, Inga; Svensson, Malin; Ecke, Holger; Kumpiene, Jurate; Maurice, Christian; Andreas, Lale; Lagerkvist, Anders

    2009-08-01

    Secondary materials could help meeting the increasing demand of landfill cover liner materials. In this study, the effect of compaction energy, water content, ash ratio, freezing, drying and biological activity on the hydraulic conductivity of two fly ash-sewage sludge mixes was investigated using a 2(7-1) fractional factorial design. The aim was to identify the factors that influence hydraulic conductivity, to quantify their effects and to assess how a sufficiently low hydraulic conductivity can be achieved. The factors compaction energy and drying, as well as the factor interactions material x ash ratio and ash ratio x compaction energy affected hydraulic conductivity significantly (alpha=0.05). Freezing on five freeze-thaw cycles did not affect hydraulic conductivity. Water content affected hydraulic conductivity only initially. The hydraulic conductivity data were modelled using multiple linear regression. The derived models were reliable as indicated by R(adjusted)(2) values between 0.75 and 0.86. Independent on the ash ratio and the material, hydraulic conductivity was predicted to be between 1.7 x 10(-11)m s(-1) and 8.9 x 10(-10)m s(-1) if the compaction energy was 2.4 J cm(-3), the ash ratio between 20% and 75% and drying did not occur. Thus, the investigated materials met the limit value for non-hazardous waste landfills of 10(-9)m s(-1). PMID:19541338

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

    SciTech Connect

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

    1992-03-01

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

  12. Isotopic tracing of landfill leachates and pollutant lead mobility in soil and groundwater.

    PubMed

    Vilomet, J D; Veron, A; Ambrosi, J P; Moustier, S; Bottero, J Y; Chatelet-Snidaro, L

    2003-10-15

    Here we provide evidence of the capability of stable lead isotopes to trace landfill leachate in a shallow groundwater. The municipal landfill we have investigated is located in southeastern France. It has no bottom liner, and wastes are placed directly on the ground. Stable lead isotopes allow the characterization of this landfill leachate signature (206Pb/207Pb = 1.189 +/- 0.004) that is clearly different from that of the local atmosphere (206Pb/207Pb = 1.150 +/- 0.006) and crustal lead (206Pb/207Pb = 1.200 +/- 0.005). Piezometers located in the direct vicinity of the landfill generally display this contaminant imprint. The landfill plume is monitored up to 1000 m downgradient of the landfill, in very good agreement with evaluation from chloride concentration. Meanwhile, 206Pb/207Pb ratios measured at a piezometer located 4600 m downgradient of the landfill suggest a contamination by the landfill plume. This result shows that the complexity of a pollutant plume dispersion in this shallow groundwater system requires several independent tracers to clearly resolve origin and transport pathways for contaminants. Furthermore, seasonal rainfall variation for this Mediterranean mixed Quaternary alluvion reservoir and the use of KCl fertilizers might favor an efficient remobilization of atmospheric lead in plowed soils and its transfer into groundwater as shown by lead isotope systematics. PMID:14594365

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

    PubMed

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

    2013-08-01

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

  14. LEACHATE CLOGGING ASSESSMENT OF GEOTEXTILE AND SOIL LANDFILL FILTERS

    EPA Science Inventory

    The liquids management strategy for any municipal or hazardous waste landfill requires a knowledgeable design strategy for the leachate collection system located at the base of the waste mass. Such leachate collection systems generally consist of sumps, perforated pipes, drainag...

  15. Soil contamination by heavy metals in landfills: measurements from an unlined leachate storage basin.

    PubMed

    Bouzayani, Fethi; Aydi, Abdelwaheb; Abichou, Tarek

    2014-08-01

    Landfills are sources of groundwater and soil pollution due to the production of leachate and its migration through refuse. This study was conducted in order to determine the extent of soil pollution within and around the Jebel Chakir landfill, located in the Tunis City, Tunisia. The main objective was to characterize soil samples of an unlined storage basin in relation to heavy metal concentrations in the Jebel Chakir landfill to the southwest of Tunis, Northern Tunisia. Twenty-four soil samples taken from different locations around the storage basin were analyzed by atomic absorption spectrophotometry for Cr, Cu, Ni, Pb, and Zn investigation. Our results indicated high concentrations of Cr (54.4-129.9 mg/kg of DM), Zn (4.1-81.8 mg/kg of DM), Ni (15.1-43.9 mg/kg of DM), Pb (5.6-16.1 mg/kg of DM), and Cu (0.2-1.84 mg/kg of DM). These results suggested that contaminant migration is controlled by an active clay layer acting as an insulating material in the landfill. It is therefore necessary to set a treatment system for the landfill leachates and place a liner under the storage basin to reduce the pollution threat. PMID:24723123

  16. The use of cover crops to manage soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops are used to manage soils for many different reasons. Inserting cover crops into fallow periods and spaces in cropping systems is a beneficial soil management practice. Natural ecosystems typically have some plants growing, covering the soil, transpiring water, taking up nutrients, fixing...

  17. A process-based inventory model for landfill CH4 emissions inclusive of seasonal soil microclimate and CH4 oxidation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have developed and field-validated an annual inventory model for California landfill CH4 emissions that incorporates both site-specific soil properties and soil microclimate modeling coupled to 0.5o scale global climatic models. Based on 1-D diffusion, CALMIM (California Landfill Methane Inventor...

  18. Contamination valuation of soil and groundwater source at anaerobic municipal solid waste landfill site.

    PubMed

    Aziz, Shuokr Qarani; Maulood, Yousif Ismael

    2015-12-01

    The present work aimed to determine the risks that formed landfill leachate from anaerobic Erbil Landfill Site (ELS) poses on groundwater source and to observe the effects of disposed municipal solid waste (MSW) on soil properties. The study further aims to fill the gap in studies on the effects of disposed MSW and produced leachate on the groundwater characteristics and soil quality at ELS, Iraq. Soil, leachate, and groundwater samples were collected from ELS for use as samples in this study. Unpolluted groundwater samples were collected from an area outside of the landfill. Field and laboratory experiments for the soil samples were conducted. Chemical analyses for the soil samples such as organic matter, total salts, and SO4 (=) were also performed. Raw leachate and groundwater samples were analyzed using physical and chemical experiments. The yields for sorptivity, steady-state infiltration rate, and hydraulic conductivity of the soil samples were 0.0006 m/√s, 0.00004 m/s, and 2.17 × 10(-5) m/s, respectively. The soil at ELS was found to be light brown clayey gravel with sand and light brown gravely lean clay layers with low permeability. Unprocessed leachate analysis identified the leachate as stabilized. Findings showed that the soil and groundwater at the anaerobic ELS were contaminated. PMID:26577215

  19. Study of Soil Washing for Remediation of Pb and Zn Contaminated Coastal Landfill

    NASA Astrophysics Data System (ADS)

    Park, S.; Kim, S.; Lee, M.

    2013-12-01

    As a result of analyzing the pre-treatment process of Pb, Zn in contaminated coastal landfill soil presented by Korean Soil Analysis Method, the each concentration was presented 577.00mg/kg, 3894.34mg/kg. This soil was critically contaminated with Pb and Zn because it was exceeded the Standard of soil contamination(2area: Pb-400mg/kg, Zn-600mg/kg). Soil remediation efficiency of the soil washing process for the removal of Pb and Zn was determined to be consistent with the results. The batch experiment on the several washing solutions(HCl, HNO3), washing solutions concentrations(0.1-0.8M) and the ratio of soil vs. solution for soil washing(1:3, 1:5 and 1:10) was performed. The results of experiments, washing time was appropriate in 30 minutes. The removal efficiency of soil washing increased as the ratio of soil vs. washing solution increased. But, in the case of heavy metals, the soil vs. solution for soil washing was determined as the optimal ratio of 1 : 5. Five consecutive soil washing with 0.5M of HCl and HNO3 solutions were performed. Results of experiments, in case of Pb was removed by target removal efficiency from soil on the twice washing. With in case of Zn was over on the first washing by target removal efficiency, but suggesting that twice consecutive soil washing is desirable as stability at field. Results of consecutive soil washing experiments, the removal efficiency maintained lower than 10 % after the 4th washing. From the results, demanding consecutive washing is not recommended. Results about the heavy metal contaminated soil washing experiments of the coastal landfill, in the case of HCl with more than 0.5 M of solution was performed at 1:5 of soil ratio vs. solution, 30 minutes of washing time and 2-3 consecutive soil washing. And in the case of HNO3 with 0.8 M of solution was performed various ratios of soil vs. washing solution, suggesting that 2-3 consecutive soil washing was reached to Pb and Zn target removal efficiency. Key words

  20. Chemical properties and biodegradability of waste paper mill sludges to be used for landfill covering.

    PubMed

    Zule, Janja; Cernec, Franc; Likon, Marko

    2007-12-01

    Waste paper mill sludges originating from different effluent treatment and de-inking installations are complex mixtures of inorganic and organic particles. Due to their favourable physico-chemical, and microbiological characteristics, they may be conveniently reused for different purposes as such or after appropriate pretreatment. Sludges from the Slovenian paper industry were extensively tested for their chemical, stability and sealing properties. During the biodegradability tests, evolutions of greenhouse gases CO2, CH4 and H2S as well as the concentrations of released volatile organic acids, such as acetic, propionic, butyric, lactic and glycollic acids as the typical degradation products of organic materials, were measured. Some other important parameters of water leachates such as pH, redox potential, content of starch and leachable ions were also evaluated. The results indicate that most of them can be efficiently applied as alternative hydraulic barrier layers for landfill construction and covering instead of the more expensive clay due to their good geomechanical properties, chemical inertness and microbiological stability. Such replacement brings about considerable economical and ecological benefits as the waste is reprocessed as secondary raw material. PMID:18229748

  1. Effect of Cover Crops on Soil Fungal Diversity and Biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of various cover crops (sordan, mustard, canola, honeysweet, and fallow) to influence soil fungal biomass and diversity were tested in a potato field in the San Luis Valley, Colorado. Soil samples (0-5 cm depth) were randomly selected from each cover crop plot and soil fungal communitie...

  2. Barometric pumping of burial trench soil gases into the atmosphere at the 740-G Sanitary Landfill

    SciTech Connect

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

    1992-12-01

    In 1991, a soil gas survey was performed at the Savannah River Site Sanitary Landfill as part of the characterization efforts required under the integrated Resource Conservation and Recovery Act (RCRA) Facility Investigation and Comprehensive Environmental Resource Conservation and Recovery Act (CERCLA) Remedial Investigation (RFI/RI) program. This report details the findings of this survey, which identified several areas of the landfill that were releasing volatile organic compounds to the atmosphere at levels exceeding regulatory standards. Knowledge of the rates of VOC outgassing is necessary to protect site workers, provide input into the human health and environmental risk assessment documents and provide input into the remedial design scenario.

  3. Estimation on the self recovery behavior of low-conductivity layer in landfill final cover by laboratory conductivity tests.

    PubMed

    Kwon, O; Park, J

    2006-11-01

    This study examined the application of a Self Recovering Sustainable Layer (SRSL) as a landfill final cover. Low-conductivity layers in landfill covers are known to have problems associated with cracking as a result of the differential settlement or climatic changes. A SRSL is defined as a layer with chemical properties that reduces the increased hydraulic conductivity resulting from cracking by forming low-conductivity precipitates of chemicals contained in the layer. In this study, the formation of precipitates was confirmed using a batch test, spectroscopic analysis and mineralogical speciation tests. The possibility of secondary contamination due to the chemicals used for recovery was evaluated using a leaching test. A laboratory conductivity test was performed on a single layer composed of each chemical as well as on a 2-layer system. The recovery performance of the SRSL was estimated by developing artificial cracks in the specimens and observing the change in hydraulic conductivity as a function of time. In the laboratory conductivity test, the hydraulic conductivity of a 2-layer system as well as those of the individual layers that comprise the 2-layer system was estimated. In addition sodium ash was found to enhance the reduction in conductivity. A significant increase in conductivity was observed after the cracks developed but this was reduced with time, which indicated that the SRSL has a proper recovering performance. In conclusion, a SRSL can be used as a landfill final cover that could maintain low-conductivity even after the serious damages due to settlement. PMID:17203605

  4. About soil cover heterogeneity of agricultural research stations' experimental fields

    NASA Astrophysics Data System (ADS)

    Rannik, Kaire; Kõlli, Raimo; Kukk, Liia

    2013-04-01

    Depending on local pedo-ecological conditions (topography, (geo) diversity of soil parent material, meteorological conditions) the patterns of soil cover and plant cover determined by soils are very diverse. Formed in the course of soil-plant mutual relationship, the natural ecosystems are always influenced to certain extent by the other local soil forming conditions or they are site specific. The agricultural land use or the formation of agro-ecosystems depends foremost on the suitability of soils for the cultivation of feed and food crops. As a rule, the most fertile or the best soils of the area, which do not present any or present as little as possible constraints for agricultural land use, are selected for this purpose. Compared with conventional field soils, the requirements for the experimental fields' soil cover quality are much higher. Experimental area soils and soil cover composition should correspond to local pedo-ecological conditions and, in addition to that, represent the soil types dominating in the region, whereas the fields should be as homogeneous as possible. The soil cover heterogeneity of seven arable land blocks of three research stations (Jõgeva, Kuusiku and Olustvere) was studied 1) by examining the large scale (1:10 000) digital soil map (available via the internet), and 2) by field researches using the transect method. The stages of soils litho-genetic and moisture heterogeneities were estimated by using the Estonian normal soils matrix, however, the heterogeneity of top- and subsoil texture by using the soil texture matrix. The quality and variability of experimental fields' soils humus status, was studied more thoroughly from the aspect of humus concentration (g kg-1), humus cover thickness (cm) and humus stocks (Mg ha-1). The soil cover of Jõgeva experimental area, which presents an accumulative drumlin landscape (formed during the last glacial period), consist from loamy Luvisols and associated to this Cambisols. In Kuusiku area

  5. Differential Soil Acidity Tolerance of Tropical Legume Cover Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In tropical regions, soil acidity and low soil fertility are the most important yield limiting factors for sustainable crop production. Using legume cover crops as mulch is an important strategy not only to protect the soil loss from erosion but also ameliorating soil fertility. Information is limit...

  6. THE USE OF ALTERNATIVE MATERIALS FOR DAILY COVER AT MUNICIPAL SOLID WASTE LANDFILLS. A Project Summary (EPA/600/SR-93/172)

    EPA Science Inventory

    This investigation was conducted to assess the applicability of currently available (ca. 1992) alternative materials for use as daily cover at landfills. Information on characteristics, material and equipment requirements, methods of preparation and application, climatic and ope...

  7. Potential use of lateritic and marine clay soils as landfill liners to retain heavy metals.

    PubMed

    Chalermyanont, Tanit; Arrykul, Surapon; Charoenthaisong, Nanthanit

    2009-01-01

    The potential of a lateritic soil and a marine clay, typical of those found in hot and humid climatic regions, was assessed for use as a landfill liner material. A series of tests were conducted - physical and chemical, batch adsorption, column, hydraulic conductivity, etc., - to evaluate the heavy metal sorption capacity, chemical compatibility of hydraulic conductivity, and transport parameters of the soils. Experimental results showed that the marine clay had better adsorption capacity than that of the lateritic soil and that its hydraulic conductivity was an order of magnitude lower. In addition, the hydraulic conductivities of both soils when permeated with low concentration heavy metal solutions were below 1x10(-7)cm/s. When permeated with Cr, Pb, Cd, Zn, and Ni solutions, the retardation factors of the lateritic soil and the marine clay ranged from 10 to 98 and 37 to 165, respectively, while the diffusion coefficients ranged from 1.0x10(-5) to 7.5x10(-6) and 3.0 to 9.14x10(-7)cm2/s, respectively. For both soils, Cr and Pb were retained relatively well, while Cd, Zn, and Ni were more mobile. The marine clay had higher retardation factors and lower diffusion coefficients, and its hydraulic conductivity was more compatible with Cr solution, than that of the lateritic soil. In general, the properties of the marine clay indicate that it has significant advantages over the lateritic soil as landfill liner material. PMID:18550353

  8. Relationship between hydraulic properties and plant coverage of the closed-landfill soils in Piacenza (Po Valley, Italy)

    NASA Astrophysics Data System (ADS)

    Cassinari, C.; Manfredi, P.; Giupponi, L.; Trevisan, M.; Piccini, C.

    2015-07-01

    In this paper the results of a study of soil hydraulic properties and plant coverage of a landfill located in Piacenza (Po Valley, Italy) are presented, together with the attempt to relate the hydraulic properties in relation with plant coverage. The measured soil water retention curve was first compared with the output of pedotransfer functions taken from the literature and then compared with the output of the same pedotransfer functions applied to a reference soil. The landfill plant coverage was also studied. The relationship between soil hydraulic properties and plant coverage showed that the landfill soils have a low water content available for plants. The soils' low water content, together with a lack of depth and a compacted structure, justifies the presence of a nitrophilous, disturbed-soil vegetation type, dominated by ephemeral annual species (therophytes).

  9. Methane emissions from MBT landfills

    SciTech Connect

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

    2013-09-15

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

  10. Microwave backscatter dependence on surface roughness, soil moisture, and soil texture. II - Vegetation-covered soil

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.; Bradley, G. A.; Dobson, M. C.

    1979-01-01

    Results are presented for an experimental investigation to determine the relationship between radar backscatter coefficient (sigma) and soil moisture for vegetation-covered soil. These results extend a previous report which showed the experimental relationship between sigma and soil moisture for bare soil. It is shown that the highest correlation between sigma and soil moisture is 0.92 for the combined response of four crop types measured at 4.25 GHz, 10 deg incidence angle, and HH polarization. Radar look direction, relative to the crop row direction, is shown to have an insignificant effect on soil-moisture estimation if the radar frequency is higher than 4 GHz. The dependence on soil type can be minimized by expressing soil moisture in units of percent of field capacity. The possibility of using a single radar for measuring soil moisture for both bare and vegetated fields is demonstrated with a linear estimation algorithm having an experimental correlation coefficinet of 0.8.

  11. [Tendencies of nematodes communities to recover after soil cover degradation].

    PubMed

    Gruzdeva, L I; Sushchuk, A A

    2010-01-01

    The way nematodes form communities on a new substrate after complete soil and plant cover degradation is studied on a model of industrial dumping. It is revealed that recovery of soil cover after degradation begins with invasion of mainly the upper soil horizon by nematodes. At the early stages, species that are resistant to unfavorable environmental conditions dominate (bacteriophages), next the abundances of carnivores and nematodes that are connected with plants increase, which indicates the process of biocenosis regeneration. PMID:21275095

  12. Relation between hydraulic properties and plant coverage of the closed-landfill soils in Piacenza (Po Valley, Italy)

    NASA Astrophysics Data System (ADS)

    Cassinari, C.; Manfredi, P.; Giupponi, L.; Trevisan, M.; Piccini, C.

    2015-02-01

    In this paper the results of a study of soil hydraulic properties and plant coverage of a landfill located in Piacenza (Po Valley, Italy) are presented, together with the attempt to put the hydraulic properties in relation with plant coverage. The measured soil water retention curve was first compared with the output of some pedotransfer functions taken from the literature and then with the output of the same pedotransfer functions applied to a reference soil. The landfill plant coverage was also studied. The relation between soil hydraulic properties and plant coverage showed that the landfill soils have a low water content available for plants and this fact, together with their lack of depth and compacted structure, justifies the presence of a nitrophilous, disturbed-soil vegetation type, dominated by ephemeral annual species (therophytes).

  13. Evolution of the soil cover of soccer fields

    NASA Astrophysics Data System (ADS)

    Belobrov, V. P.; Zamotaev, I. V.

    2014-04-01

    A soccer field can be considered a soil-like technogenic formation (STF). According to the theory of soil cover patterns, the artificially constructed (anthropogenic) soil cover of a soccer field is an analogue of a relatively homogeneous elementary soil area. However, the spatial homogeneity of the upper part (50-80 cm) of the STF of soccer fields is unstable and is subjected to gradual transformation under the impact of pedogenetic processes, agrotechnical loads, and mechanical loads during the games. This transformation is favored by the initial heterogeneity of the deep (buried) parts of the STF profile. The technogenic factors and elementary pedogenetic processes specify the dynamic functioning regime of the STF. In 50-75 years, the upper part of the STF is transformed into soil-like bodies with properties close to those in zonal soils. Certain micro- and nanopatterns of the soil cover are developed within the field creating its spatial heterogeneity.

  14. Enhanced Cover Assessment Project:Soil Manipulation and Revegetation Tests

    SciTech Connect

    Waugh, W. Joseph; Albright, Dr. Bill; Benson, Dr. Craig

    2014-02-01

    The U.S. Department of Energy Office of Legacy Management is evaluating methods to enhance natural changes that are essentially converting conventional disposal cell covers for uranium mill tailings into water balance covers. Conventional covers rely on a layer of compacted clayey soil to limit exhalation of radon gas and percolation of rainwater. Water balance covers rely on a less compacted soil “sponge” to store rainwater, and on soil evaporation and plant transpiration (evapotranspiration) to remove stored water and thereby limit percolation. Over time, natural soil-forming and ecological processes are changing conventional covers by increasing hydraulic conductivity, loosening compaction, and increasing evapotranspiration. The rock armor on conventional covers creates a favorable habitat for vegetation by slowing soil evaporation, increasing soil water storage, and trapping dust and organic matter, thereby providing the water and nutrients needed for plant germination, survival, and sustainable transpiration. Goals and Objectives Our overall goal is to determine if allowing or enhancing these natural changes could improve cover performance and reduce maintenance costs over the long term. This test pad study focuses on cover soil hydrology and ecology. Companion studies are evaluating effects of natural and enhanced changes in covers on radon attenuation, erosion, and biointrusion. We constructed a test cover at the Grand Junction disposal site to evaluate soil manipulation and revegetation methods. The engineering design, construction, and properties of the test cover match the upper three layers of the nearby disposal cell cover: a 1-foot armoring of rock riprap, a 6-inch bedding layer of coarse sand and gravel, and a 2-foot protection layer of compacted fine soil. The test cover does not have a radon barrier—cover enhancement tests leave the radon barrier intact. We tested furrowing and ripping as means for creating depressions parallel to the slope

  15. Radar reflectivity of bare and vegetation-covered soil

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.; Dobson, M. C.; Bradley, G. A.

    1981-01-01

    Radar sensitivity to soil moisture content has been investigated experimentally for bare and vegetation-covered soil using detailed spectral measurements obtained by a truck-mounted radar spectrometer in the 1-8 GHz band and by airborne scatterometer observations at 1.6, 4.75, and 13.3 GHz. It is shown that radar can provide quantitative information on the soil moisture content of both bare and vegetation-covered soil. The observed soil moisture is in the form of the soil matric potential or a related quantity such as the percent of field capacity. The depth of the monitored layer varies from 1 cm for very wet soil to about 15 cm for very dry soil.

  16. Changes in soil characteristics during landfill leachate irrigation of Populus deltoides.

    PubMed

    Zupanc, Vesna; Justin, Maja Zupančič

    2010-11-01

    The effects of wastewater application on electrical conductivity, water retention and water repellency of soils planted with Populus deltoides (eastern cottonwood) and irrigated with different concentrations of landfill leachate and compost wastewater, tap water and nutrient solution were evaluated. Substrate water content at field capacity (-0.033 MPa) and at permanent wilting point (-1.5 MPa) was determined with a pressure plate extractor to assess available water capacity of the substrate. A water drop penetration test was used to determine substrate water repellency. The biomass of nutrient and landfill leachate treatments was significantly (P<0.05) greater compared to the tap water and compost wastewater treatments. All treatments increased substrate water content at field capacity and at permanent wilting point. Landfill leachate significantly increased available water capacity (up to 52%); treatment with compost wastewater significantly decreased it (25-47%). All substrates showed increased water repellency after the experiment at field capacity and permanent wilting point comparing to the original substrate. The strongest influence on water repellency at both field capacity and permanent wilting point showed irrigation with compost wastewater and tap water. Pronounced influence on substrate's water repellency of compost wastewater could be contributed to a high content of dissolved organic carbon, whereas Mg and Ca cations caused flocculation and consequent water repellency of the substrate irrigated with tap water. The results indicate that soil physical characteristics must be closely monitored when landfill leachate and compost wastewater are used for irrigation to avoid long term detrimental effects on the soil, and consequently on the environment. Due to the complexity of the compost wastewater quality the latter should be applied on open fields only after prior pre-treatment to reduce dissolved organic carbons, or alternatively, compost wastewater

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

    SciTech Connect

    McVey, M.D.; Goering, T.J.; Peace, J.L.

    1996-02-01

    The Environmental Restoration Project at Sandia National Laboratories, New Mexico is tasked with assessing and remediating the Mixed Waste Landfill in Technical Area III. The Mixed Waste Landfill is a 2.6 acre, inactive radioactive and mixed waste disposal site. In 1993 and 1994, an extensive passive and active soil gas sampling program was undertaken to identify and quantify volatile organic compounds in the subsurface at the landfill. Passive soil gas surveys identified levels of PCE, TCE, 1,1, 1-TCA, toluene, 1,1,2-trichlorotrifluoroethane, dichloroethyne, and acetone above background. Verification by active soil gas sampling confirmed concentrations of PCE, TCE, 1,1,1-TCA, and 1,1,2-trichloro-1,2,2-trifluoroethane at depths of 10 and 30 feet below ground surface. In addition, dichlorodifluoroethane and trichlorofluoromethane were detected during active soil gas sampling. All of the volatile organic compounds detected during the active soil gas survey were present in the low ppb range.

  18. In-situ studies on the performance of landfill caps (compacted soil liners, geomembranes, geosynthetic clay liners, capillary barriers)

    SciTech Connect

    Melchior, S.

    1997-12-31

    Since 1986 different types of landfill covers have been studied in-situ on the Georgswerder landfill in Hamburg, Germany. Water balance data are available for eight years. The performance of different carriers has been measured by collecting the leakage on areas ranging from 100 m{sup 2} to 500 m{sup 2}. Composite liners with geomembranes performed best, showing no leakage. An extended capillary barrier also performed well. The performance of compacted soil liners, however, decreased severely within five years due to desiccation, shrinkage and plant root penetration (liner leakage now ranging from 150 mm/a to 200 mm/a). About 50 % of the water that reaches the surface of the liner is leaking through it. The maximum leakage rates have increased from 2 x 10{sup -10} m{sup 3} m{sup -2} s{sup -1} to 4 x 10{sup -8} m{sup 3} m{sup -2} s{sup -1}. Two types of geosynthetic clay liners (GCL) have been tested for two years now with disappointing results. The GCL desiccated during the first dry summer of the study. High percolation rates through the GCL were measured during the following winter (45 mm resp. 63 mm in four months). Wetting of the GCL did not significantly reduce the percolation rates.

  19. Evaluation of engineering properties for the use of leached brown coal ash in soil covers.

    PubMed

    Mudd, Gavin M; Chakrabarti, Srijib; Kodikara, Jayantha

    2007-01-31

    The need to engineer cover systems for the successful rehabilitation or remediation of a wide variety of solid wastes is increasing. Some common applications include landfills, hazardous waste repositories, or mine tailings dams and waste rock/overburden dumps. The brown coal industry of the Latrobe Valley region of Victoria, Australia, produces significant quantities of coal ash and overburden annually. There are some site-specific acid mine drainage (AMD) issues associated with overburden material. This needs to be addressed both during the operational phase of a project and during rehabilitation. An innovative approach was taken to investigate the potential to use leached brown coal ash in engineered soil covers on this overburden dump. The basis for this is two-fold: first, the ash has favourable physical characteristics for use in cover systems (such as high storage capacity/porosity, moderately low permeability, and an ability to act as a capillary break layer generating minimal leachate or seepage); and second, the leachate from the ash is mildly alkaline (which can help to mitigate and reduce the risk of AMD). This paper will review the engineering issues involved in using leached brown coal ash in designing soil covers for potentially acid-forming overburden dumps. It presents the results of laboratory work investigating the technical feasibility of using leached brown coal ash in engineered solid waste cover systems. PMID:16621267

  20. Effect of Landfill Leachate on Cereal Nutrition and Productivity and on Soil Properties.

    PubMed

    Panchoni, Luciana C; Santos, Cristiane A; Kuwano, Biana H; Carmo, Kellen B; Cely, Martha V T; Oliveira-Júnior, Admilton G; Fagotti, Dáfila S L; Cervantes, Vivian N M; Zangaro, Waldemar; Andrade, Diva S; Andrade, Galdino; Nogueira, Marco A

    2016-05-01

    Landfill leachates carry nutrients, especially N and K, which can be recycled in cropping systems. We applied doses of landfill leachate (0 [Control], 32.7, 65.4, 98.1, and 130.8 m ha) three times in 2008 and three times in 2009 on a clay Rhodic Kandiudult soil. In 2009, black oat ( L.) and corn ( L.) were cropped in succession and assessed for concentration of nutrients in leaves and for shoot biomass and grain yield, respectively. As a positive control, an additional treatment with urea (120 kg ha of N) was studied in corn. Soil was sampled at four depths (down to 60 cm) in three sampling dates to assess chemical and biochemical properties. Concentration of nutrients in leaves, oat biomass (8530-23,240 kg ha), and corn grain yield (4703-8807 kg ha) increased with increasing doses of leachate. There was a transient increase in the concentration of nitrate in soil (3-30 mg kg), increasing the risk of N losses by leaching at doses above 120 kg ha N, as revealed by an estimated N balance in the cropping system. Sodium and K in soil also increased with increasing doses of leachate but decreased as rainfall occurred. The activity of dehydrogenase decreased about 30% from the control to the highest dose of leachate and urea, suggesting an inhibitory effect of mineral N on microbial metabolism. Landfill leachate was promising as a source of N and K for crop productivity and caused minor or transient effects on soil properties. PMID:27136177

  1. Methane oxidation in a boreal climate in an experimental landfill cover composed from mechanically-biologically treated waste.

    PubMed

    Einola, J-K M; Sormunen, K M; Rintala, J A

    2008-12-15

    The present study evaluated microbial methane (CH4) oxidation in a boreally located outdoor landfill lysimeter (volume 112 m3, height 3.9 m) filled with mechanically-biologically treated waste (MBT residual) and containing a cover layer made from the same MBT residual. The calculations based on gas emission and pore gas measurements showed that, between April and October 2005, a significant proportion (> 96%) of the methane produced (< 23 l CH4 m(-2) d(-1)) in the lysimeter was oxidized. Methane was oxidized mainly at the depths of 35-75 cm, as indicated by the upward decrease both in the methane concentration and in the methane-to-carbon dioxide ratio in the pore gas. Lower methane oxidation (< 0.8 CH4 m(-2) d(-1); this was < 22% of the methane produced) was observed only during the coldest time of the year (January 2006), apparently due to the fall in temperature at the depths of 25-70 cm (from 9-25 degrees C during April to October to 2-9 degrees C in January). Unexpectedly, the highest methane oxidation potential (MOP) was observed in samples from the top layer where exposure to methane was low. Overall, the results show that MBT residual is a suitable support medium for methane oxidation in landfill covers in field conditions in a boreal climate. PMID:18823644

  2. Design of landfill daily cells.

    PubMed

    Panagiotakopoulos, D; Dokas, I

    2001-08-01

    The objective of this paper is to study the behaviour of the landfill soil-to-refuse (S/R) ratio when size, geometry and operating parameters of the daily cell vary over realistic ranges. A simple procedure is presented (1) for calculating the cell parameters values which minimise the S/R ratio and (2) for studying the sensitivity of this minimum S/R ratio to variations in cell size, final refuse density, working face length, lift height and cover thickness. In countries where daily soil cover is required, savings in landfill space could be realised following this procedure. The sensitivity of minimum S/R to variations in cell dimensions decreases with cell size. Working face length and lift height affect the S/R ratio significantly. This procedure also offers the engineer an additional tool for comparing one large daily cell with two or more smaller ones, at two different working faces within the same landfill. PMID:11720268

  3. Soil cover by natural trees in agroforestry systems

    NASA Astrophysics Data System (ADS)

    Diaz-Ambrona, C. G. H.; Almoguera Millán, C.; Tarquis Alfonso, A.

    2009-04-01

    The dehesa is common agroforestry system in the Iberian Peninsula. These open oak parklands with silvo-pastoral use cover about two million hectares. Traditionally annual pastures have been grazed by cows, sheep and also goats while acorns feed Iberian pig diet. Evergreen oak (Quercus ilex L.) has other uses as fuelwood collection and folder after tree pruning. The hypothesis of this work is that tree density and canopy depend on soil types. We using the spanish GIS called SIGPAC to download the images of dehesa in areas with different soil types. True colour images were restoring to a binary code, previously canopy colour range was selected. Soil cover by tree canopy was calculated and number of trees. Processing result was comparable to real data. With these data we have applied a dynamic simulation model Dehesa to determine evergreen oak acorn and annual pasture production. The model Dehesa is divided into five submodels: Climate, Soil, Evergreen oak, Pasture and Grazing. The first three require the inputs: (i) daily weather data (maximum and minimum temperatures, precipitation and solar radiation); (ii) the soil input parameters for three horizons (thickness, field capacity, permanent wilting point, and bulk density); and (iii) the tree characterization of the dehesa (tree density, canopy diameter and height, and diameter of the trunk). The influence of tree on pasture potential production is inversely proportional to the canopy cover. Acorn production increase with tree canopy cover until stabilizing itself, and will decrease if density becomes too high (more than 80% soil tree cover) at that point there is competition between the trees. Main driving force for dehesa productivity is soil type for pasture, and tree cover for acorn production. Highest pasture productivity was obtained on soil Dystric Planosol (Alfisol), Dystric Cambisol and Chromo-calcic-luvisol, these soils only cover 22.4% of southwest of the Iberian peninssula. Lowest productivity was

  4. Monitoring the Performance of an Alternative Landfill Cover at the Monticello, Utah, Uranium Mill Tailings Disposal Site

    SciTech Connect

    Waugh, W.J.; Kastens, M.K.; Sheader, L.R.L.; Benson, C.H.; Albright, W.H.; Mushovic, P.S.

    2008-07-01

    The U.S. Department of Energy Office of Legacy Management (DOE) and the U.S. Environmental Protection Agency (EPA) collaborated on the design and monitoring of an alternative cover for the Monticello uranium mill tailings disposal cell, a Superfund site in southeastern Utah. Ground-water recharge is naturally limited at sites like Monticello where thick, fine-textured soils store precipitation until evaporation and plant transpiration seasonally return it to the atmosphere. The cover at Monticello uses local soils and a native plant community to mimic the natural soil water balance. The cover is fundamentally an evapotranspiration (ET) design with a capillary barrier. A 3-hectare drainage lysimeter was embedded in the cover during construction of the disposal cell in 2000. The lysimeter consists of a geo-membrane liner below the capillary barrier that directs percolation water to a monitoring system. Soil water storage is determined by integration of point water content measurements. Meteorological parameters are measured nearby. Plant cover, shrub density, and leaf area index (LAI) are monitored annually. The cover performed well over the 7-year monitoring period (2000-2007). The cumulative percolation was 4.2 mm (0.6 mm yr{sup -1}), satisfying an EPA goal of an average percolation of <3.0 mm yr{sup -1}. Almost all percolation can be attributed to the exceptionally wet winter and spring of 2004-2005 when soil water content slightly exceeded the water storage capacity of the cover. The diversity, percent cover, and LAI of vegetation increased over the monitoring period, although the density of native shrubs that extract water from deeper in the cover has remained less than revegetation targets. DOE and EPA are applying the monitoring results to plan for long-term surveillance and maintenance and to evaluate alternative cover designs for other waste disposal sites. (authors)

  5. Cover cropping impacts on arbuscular mycorrhizal fungi and soil aggregation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops are a management tool which can extend the period of time that a living plant is growing and conducting photosynthesis. This is critical for soil health, because most of the soil organisms, particularly the arbuscular mycorrhizal fungi, are limited by carbon. Research, on-farm, and demon...

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

    SciTech Connect

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

    1998-08-01

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

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

    USGS Publications Warehouse

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

    2011-01-01

    Soil gas, soil, and water were assessed for organic and inorganic constituents at the former hospital landfill located in a 75-acre study area near the Dwight D. Eisenhower Army Medical Center, Fort Gordon, Georgia, from April to September 2010. Passive soil-gas samplers were analyzed to evaluate organic constituents in the hyporheic zone of a creek adjacent to the landfill and soil gas within the estimated boundaries of the former landfill. Soil and water samples were analyzed to evaluate inorganic constituents in soil samples, and organic and inorganic constituents in the surface water of a creek adjacent to the landfill, respectively. This assessment was conducted to provide environmental constituent data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Results from the hyporheic-zone assessment in the unnamed tributary adjacent to the study area indicated that total petroleum hydrocarbons and octane were the most frequently detected organic compounds in groundwater beneath the creek bed. The highest concentrations for these compounds were detected in the upstream samplers of the hyporheic-zone study area. The effort to delineate landfill activity in the study area focused on the western 14 acres of the 75-acre study area where the hyporheic-zone study identified the highest concentrations of organic compounds. This also is the part of the study area where a debris field also was identified in the southern part of the 14 acres. The southern part of this 14-acre study area, including the debris field, is steeper and not as heavily wooded, compared to the central and northern parts. Fifty-two soil-gas samplers were used for the July 2010 soil-gas survey in the 14-acre study area and mostly detected total petroleum hydrocarbons, and gasoline and diesel compounds. The highest soil-gas masses for total petroleum hydrocarbons, diesel compounds, and the only valid detection of perchloroethene

  8. Minimisation of N2O emissions from a plant-soil system under landfill leachate irrigation.

    PubMed

    Zhang, Hou-Hu; He, Pin-Jing; Shao, Li-Ming; Yuan, Li

    2009-03-01

    The irrigation of a plant-soil system with landfill leachate should promote the formation of N2O due to the introduction of organic carbon and mineralized-N and the elevation of the moisture content. Laboratory incubation was performed to minimize N2O emissions from a leachate irrigated plant-soil system by manipulating leachate NH(4)(+)-N loading, moisture content, and soil type. A field investigation, consisting of three plots planted with Cynodon dactylon, Nerium indicum Mill, and Festuca arundinacea Schreb, was then conducted to select plant species. There was almost no difference in N2O emissions between soil moisture contents of 46% and 55% water-filled pore space (WFPS), while a sharp increase occurred at 70% WFPS. N2O fluxes were significantly correlated with leachate NH4(+)-N loading. Amongst the physiochemical characteristics of the selected nine soils, only soil pH was significantly correlated with N2O fluxes. Compared with fertilizers application in other ecosystems, N2O turnover rate from the plant-soil system under leachate irrigation was relatively lower. Therefore, avoiding high NH4(+)-N loadings and excessively wet conditions (<60% WFPS) and cultivating conifer plants of stronger sunlight penetration with less litter deposit on acidic sandy soil could minimize potential N2O emissions under leachate irrigation. PMID:18835706

  9. Phytoextraction of As and Fe using Hibiscus cannabinus L. from soil polluted with landfill leachate.

    PubMed

    Meera, M; Agamuthu, P

    2012-02-01

    Terrestrial plants as potential phytoremediators for remediation of surface soil contaminated with toxic metals have gained attention in clean-up technologies. The potential of kenaf (Hibiscus cannabinus L.) to offer a cost-effective mechanism to remediate Fe and As from landfill leachate-contaminated soil was investigated. Pot experiment employing soil polluted with treatments of Jeram landfill leachate was conducted for 120 days. Plants were harvested after 8th, 12th, and 16th weeks of growth. Accumulation of Fe and As was assessed based on Bioconcentration Factor and Translocation Factor. Results showed sequestration of 0.06-0.58 mg As and 66.82-461.71 mg Fe per g plant dry weight in kenaf root, which implies that kenaf root can be an bioavailable sink for toxic metals. Insignificant amount of Fe and As was observed in the aerial plant parts (< 12% of total bioavailable metals). The ability of kenaf to tolerate these metals and avoid phytotoxicity could be attributed to the stabilization of the metals in the roots and hence reduction of toxic metal mobility (TF < 1). With the application of leachate, kenaf was also found to have higher biomass and subsequently recorded 11% higher bioaccumulation capacity, indicating its suitability for phytoextraction of leachate contaminated sites. PMID:22567704

  10. Cover crops effectiveness for soil erosion control in Sicilian vineyard

    NASA Astrophysics Data System (ADS)

    Gristina, L.; Novara, A.; Saladino, S.; Santoro, A.

    2009-04-01

    In vineyards, which are very common in Mediterranean area, cover crops are becoming increasingly used to reduce soil erosion. Cover crops reduce runoff by increasing infiltration and increasing roughness and then reducing the ovelandflow velocity. The aim of the present study was to quantify soil and water losses under different soil managements systems on vineyards. The study site was a Sauvignon blanc winegrape vineyard located in Southwestern Sicily. Vineyards were managed both traditionally (conventional tillage) and alternative management using cover crops: 1) Vicia faba ; 2) Vicia faba and Vicia sativa; 3) Trifolium subterraneum, Lolium perenne, Festuca rubra; 4)Trifolium subterraneum, Festuca rubra and Festuca ovina, 5) Triticum durum, 6) Triticum durum and Vicia sativa. To monitor water and sediment yield, a Gerlach trough was installed at each treatment on the vineyard inter-row, with the row vineyard used as a border (topographical border). Runoff was measured after each rainfall event (raingauge 0.2 mm accuracy) from November 2005 to April 2007. And sediments were measured after desiccation. The results show that runoff and erosion were reduced considerably under the treatments with Trifolium subterraneum, Lolium perenne, Festuca rubra and Trifolium subterraneum, Festuca rubra and Festuca ovina (treatments 3 and 4). The soil losses were reduced by 73% under treatment 4 compared to the tillage plot. Conventional tillage and alternative management using Vicia faba cover crop (treatment 1) result the most ineffective treatment to soil erosion. These results show that the use of a cover crop can be a simple soil and water conservation practice in Sicilian vineyards. Key words: soil erosion, cover crops, vineyard, Mediterranean area.

  11. The release of As, Cr and Cu from contaminated soil stabilized with APC residues under landfill conditions.

    PubMed

    Travar, I; Kihl, A; Kumpiene, J

    2015-03-15

    The aim of this study was to investigate the stability of As, Cr and Cu in contaminated soil treated with air pollution control residues under landfill conditions. The influence of landfill gas and temperature on the release of trace elements from stabilized soil was simulated using a diffusion test. The air pollution control residues immobilized As through the precipitation of Ca-As minerals (calcium arsenate (Ca5H2(AsO4)3 × 5H2O), weilite (CaAsO4) and johnbaumite (Ca5(AsO4)3(OH)), incorporation of As into ettringite (Ca6Al2(SO4)3(OH)12 × 26H2O) and adsorption by calcite (CaCO3). The air pollution control residues generally showed a high resistance to pH reduction, indicating high buffer capacity and stability of immobilized As in a landfill over time. Generation of heat in a landfill might increase the release of trace elements. The release of As from stabilized soil was diffusion-controlled at 60 °C, while surface wash-off, dissolution, and depletion prevailed at 20 °C. The air pollution control residues from the incineration of municipal solid waste immobilized Cr, indicating its stability in a landfill. The treatment of soil with air pollution control residues was not effective in immobilization of Cu. Contaminated soils treated with air pollution control residues will probably have a low impact on overall leachate quality from a landfill. PMID:25528268

  12. Coupled Environmental Processes and Long-term Performance of Landfill Covers in the northern Mojave Desert

    SciTech Connect

    David Shafer; Michael Young; Stephen Zitzer; Eric McDonald; Todd Caldwell

    2004-05-12

    Evapotransiration (ET) covers have gained widespread acceptance as a closure feature for waste disposal sites, particularly in the arid and semi-arid regions of the southwestern U.S. But as landforms, ET covers are subject to change over time because of processes such as pedogenesis, hydrologic processes, vegetation establishment and change, and biological processes. To better understand the effects of coupled process changes to ET covers, a series of four primary analog sites in Yucca Flat on the Nevada Test Site, along with measurements and observations from other locations in the Mojave Desert, were selected to evaluate changes in ET covers over time. The analog sites, of varying ages, were selected to address changes in the early post-institutional control period, the 1,000-year compliance period for disposal of low-level and mixed low-level waste, and the 10,000-year compliance period for transuranic waste sites.

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

    USGS Publications Warehouse

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

    2012-01-01

    Soil-gas and groundwater assessments were conducted at the Gibson Road landfill in 201 to provide screening-level environmental contamination data to supplement the data collected during previous environmental studies at the landfill. Passive samplers were used in both assessments to detect volatile and semivolatile organic compounds and polycyclic aromatic hydrocarbons in soil gas and groundwater. A total of 56 passive samplers were deployed in the soil in late July and early August for the soil-gas assessment. Total petroleum hydrocarbons (TPH) were detected at masses greater than the method detection level of 0.02 microgram in all samplers and masses greater than 2.0 micrograms in 13 samplers. Three samplers located between the landfill and a nearby wetland had TPH masses greater than 20 micrograms. Diesel was detected in 28 of the 56 soil-gas samplers. Undecane, tridecane, and pentadecane were detected, but undecane was the most common diesel compound with 23 detections. Only five detections exceeded a combined diesel mass of 0.10 microgram, including the highest mass of 0.27 microgram near the wetland. Toluene was detected in only five passive samplers, including masses of 0.65 microgram near the wetland and 0.85 microgram on the southwestern side of the landfill. The only other gasoline-related compound detected was octane in two samplers. Naphthalene was detected in two samplers in the gully near the landfill and two samplers along the southwestern side of the landfill, but had masses less than or equal to 0.02 microgram. Six samplers located southeast of the landfill had detections of chlorinated compounds, including one perchloroethene detections (0.04 microgram) and five chloroform detections (0.05 to0.08 microgram). Passive samplers were deployed and recovered on August 8, 2011, in nine monitoring wells along the southwestern, southeastern and northeastern sides of the landfill and down gradient from the eastern corner of the landfill. Six of the nine

  14. Relic components within the soil cover of Mexico: regional variability

    NASA Astrophysics Data System (ADS)

    Solleiro Rebolledo, Elizabeth; Sedov, Sergey

    2015-04-01

    The case of paleosols persisting on the land surface (non-buried paleosols or relict soils) besides paleoecological interest has specific implications for studies of soil geography, ecology and management. In fact these soil bodies form part of the modern soil mantle and provide ecological services for the current (agro)ecosystems but are neither formed nor re-produced by these ecosystems, conforming locally extinct soils (although similar profiles can develop at present under other bioclimatic conditions). In consequence, they are a heritage of past climatic and biotic conditions now extinct, thus presenting a non-restorable component of the present landscape. Mexico has so abundant and diverse paleosols, both surface and buried, that really could be considered to be a "paleopedological paradise". Two groups of factors promote generation of this abundance: Major part of territory of Mexico is occupied by mountainous landscapes with high intensity of tectonic, volcanic and geomorphic processes. These processes create a complex mosaic of geological materials and landforms of different age (like alluvial and lake terraces, eroded slopes, and volcanic deposits of various eruptions). Meanwhile younger landsurfaces are occupied by the recently developed soils, the older ones could bear the relict soil bodies. The same processes produce sedimentary strata (alluvial, colluvial, pyroclastic, etc.) which frequently cover the pre-existing landsurfaces and soils, producing series of buried paleosols. In this work we present three study cases of relict paleosols that are integrated to the modern soil cover of Mexico: the case of reddish-brown soils in the arid landscapes of Sonora (in the north); the pedosediments (tepetates) in central Mexico; and the red soils developed under humid conditions in Yucatan (in the south).

  15. Analysis of landfills with historic airphotos

    NASA Technical Reports Server (NTRS)

    Erb, T. L.; Philipson, W. R.; Teng, W. L.; Liang, T.

    1981-01-01

    An investigation is conducted regarding the value of existing aerial photographs for waste management, including landfill monitoring. The value of historic aerial photographs for documenting landfill boundaries is shown in a graph in which the expansion of an active landfill is traced over a 40-year period. Historic aerial photographs can also be analyzed to obtain general or detailed land-use and land-cover information. In addition, the photographs provide information regarding other elements of the physical environment, including geology, soils, and surface and subsurface drainage. The value of historic photos is discussed, taking into account applications for inventory, assessing contamination/health hazards, planning corrective measures, planning waste collection and facilities, developing inactive landfills, and research concerning improved land-filling operations.

  16. The use of volcanic soil as mineral landfill liner--I. Physicochemical characterization and comparison with zeolites.

    PubMed

    Navia, Rodrigo; Hafner, Georg; Raber, Georg; Lorber, Karl E; Schöffmann, Elke; Vortisch, Walter

    2005-06-01

    The main physicochemical characteristics of the volcanic soil of Southern Chile, with allophane as the main pedogenic mineral phase were analysed and compared with common zeolites (clinoptilolite) of the European market. The ultimate goal of this study was to test volcanic soil for the use as mineral landfill liner. The main results indicated that the clay and silt fractions together of the volcanic soil were between 38 and 54%. The buffering capacity of the volcanic soil was higher compared with the studied zeolites, whereas the cationic exchange capacity of the volcanic soil (between 5.2 and 6.5 cmol + kg(-1)) is of the same order of magnitude of the studied zeolites (between 9.7 and 11.4 cmol + kg(-1)). Moreover, the anionic exchange capacity of the volcanic soil was higher compared to the zeolites analysed. The hydraulic conductivity of the volcanic soil, measured in the laboratory at maximum proctor density, ranges between 5.16 x 10(-9) and 6.48 x 10(-9) m s(-1), a range that is comparable to the value of 4.51 x 10(-9) m s(-1) of the studied zeolite. The Proctor densities of the volcanic soil are in a lower range (between 1.11 and 1.15 g ml(-1)) compared with zeolites (between 1.19 and 1.34 g ml(-1)). The volcanic soil physicochemical characteristics are comparable to all the requirements established in the Austrian landfill directive (DVO, 2000). Therefore, the use as mineral landfill basal sealing of the analysed volcanic soil appears reasonable, having a pollutant adsorption capacity comparable to zeolites. It is of special interest for Southern Chile, because there are no alternative mineral raw materials for basal liners of landfills. PMID:15988944

  17. Passive soil venting at the Chemical Waste Landfill Site at Sandia National Laboratories, Albuquerque, New Mexico

    SciTech Connect

    Phelan, J.M.; Reavis, B.; Cheng, W.C.

    1995-05-01

    Passive Soil Vapor Extraction was tested at the Chemical Waste Landfill (CWL) site at Sandia National Laboratories, New Mexico (SNLIW). Data collected included ambient pressures, differential pressures between soil gas and ambient air, gas flow rates into and out of the soil and concentrations of volatile organic compounds (VOCS) in vented soil gas. From the differential pressure and flow rate data, estimates of permeability were arrived at and compared with estimates from other studies. Flow, differential pressure, and ambient pressure data were collected for nearly 30 days. VOC data were collected for two six-hour periods during this time. Total VOC emissions were calculated and found to be under the limit set by the Resource Conservation and Recovery Act (RCRA). Although a complete process evaluation is not possible with the data gathered, some of the necessary information for designing a passive venting process was determined and the important parameters for designing the process were indicated. More study is required to evaluate long-term VOC removal using passive venting and to establish total remediation costs when passive venting is used as a polishing process following active soil vapor extraction.

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

    USGS Publications Warehouse

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

    2012-01-01

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

  19. Soil Nitrogen Response to Coupling Cover Crops with Manure Injection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coupling winter small grain cover crops (CC) with manure (M) application may increase retention of manure nitrogen (N) in corn-soybean cropping systems. The objective of this research was to quantify soil N changes after application of liquid swine M (Sus scrofa L.) at target N rates of 112, 224, an...

  20. Coupling Cover Crops and Manure Injection: Soil Inorganic N Changes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Integration of a rye/oat cover crop with liquid swine manure application may enhance retention of manure nitrogen (N) in corn-soybean cropping systems. The objective of this study was to evaluate changes in soil inorganic N following injection of liquid swine manure to plots seeded with a rye/oat co...

  1. Beneficial uses of recycled asphalt-stabilized products as landfill cover and capping systems

    SciTech Connect

    Camougis, G.

    1996-12-31

    The American Reclamation Corporation (AMREC{reg_sign}) has played a major role in the development of new programs for the recycling of discarded materials from construction, demolition, remediation and manufacturing operations. Excavated petroleum-contaminated soils (oily soils), asphalt paving, concrete rubble, and discarded asphalt roofing shingles have been processed and recycled into beneficially useful construction products. AMREC uses a cold-mix, asphalt-emulsion technology to process many of the recyclables received at its recycling facility in Charlton, MA. Recyclable materials are processed and blended to produce recycled, asphalt-stabilized products. In addition, recycled, asphalt-stabilized products are being investigated and tested for other beneficial uses. This includes their uses as capping materials and as containment materials.

  2. Irrigating poplar energy crops with landfill leachate negatively affects soil micro- and meso-fauna.

    PubMed

    Coyle, David R; Zalesny, Jill A; Zalesny, Ronald S; Wiese, Adam H

    2011-10-01

    Increased municipal solid waste generated worldwide combined with substantial demand for renewable energy has prompted testing and deployment of woody feedstock production systems that reuse and recycle wastewaters as irrigation and fertilization. Populus selections are ideal for such systems given their fast growth, extensive root systems, and high water usage rates. Maintaining ecological sustainability (i.e., the capacity for an ecosystem to maintain its function and retain its biodiversity over time) during tree establishment and development is an important component of plantation success, especially for belowground faunal populations. To determine the impact of solid waste leachate on soil micro- and meso-fauna, we compared soilfrom eight different Populus clones receiving municipal solid waste landfill leachate irrigation with clones receiving fertilized (N, P K) well water irrigation. Microfauna (i.e., nematodes) communities were more diverse in control soils. Mesofauna (i.e., insects) were associated with all clones; however, they were four times more abundant around trees found within the control plot than those that received leachate treatments. Nematode and insect abundance varied among Populus clones yet insect diversity was greater in the leachate-treated soils. Phytotechnologies must allow for soil faunal sustainability, as upsetting this balance could lead to great reductions in phytotechnology efficacy. PMID:21972508

  3. Radon diffusion in candidate soils for covering uranium mill tailings

    SciTech Connect

    Silker, W.B.; Kalkwarf, D.R.

    1983-04-01

    Diffusion coefficients were measured for radon in 34 soils that had been identified by mill personnel as candidate covers for their tailings piles in order to reduce radon emission. These coefficients referred to diffusion in the total pore space of the soils. They were measured in the laboratory by a steady-state method using soil columns compacted to greater than 80% of their Proctor maximum packing densities but with moisture contents generally less than would be expected at a tailings site. An empirical equation was used to extrapolate measured coefficients to value expected at soil-moisture contents representative of tailings sites in the western United States. Extrapolated values for silty sands and clayey sands ranged from 0.004 to 0.06 cm/sup 2//s. Values for inorganic silts and clays ranged from 0.001 to 0.02 cm/sup 2//s.

  4. Barometric pumping of burial trench soil gases into the atmosphere at the 740-G Sanitary Landfill. Revision 1

    SciTech Connect

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

    1992-12-01

    In 1991, a soil gas survey was performed at the Savannah River Site Sanitary Landfill as part of the characterization efforts required under the integrated Resource Conservation and Recovery Act (RCRA) Facility Investigation and Comprehensive Environmental Resource Conservation and Recovery Act (CERCLA) Remedial Investigation (RFI/RI) program. This report details the findings of this survey, which identified several areas of the landfill that were releasing volatile organic compounds to the atmosphere at levels exceeding regulatory standards. Knowledge of the rates of VOC outgassing is necessary to protect site workers, provide input into the human health and environmental risk assessment documents and provide input into the remedial design scenario.

  5. Evaporative losses from soils covered by physical and different types of biological soil crusts

    USGS Publications Warehouse

    Chamizo, S.; Cantón, Y.; Domingo, F.; Belnap, J.

    2013-01-01

    Evaporation of soil moisture is one of the most important processes affecting water availability in semiarid ecosystems. Biological soil crusts, which are widely distributed ground cover in these ecosystems, play a recognized role on water processes. Where they roughen surfaces, water residence time and thus infiltration can be greatly enhanced, whereas their ability to clog soil pores or cap the soil surface when wetted can greatly decrease infiltration rate, thus affecting evaporative losses. In this work, we compared evaporation in soils covered by physical crusts, biological crusts in different developmental stages and in the soils underlying the different biological crust types. Our results show that during the time of the highest evaporation (Day 1), there was no difference among any of the crust types or the soils underlying them. On Day 2, when soil moisture was moderately low (11%), evaporation was slightly higher in well-developed biological soil crusts than in physical or poorly developed biological soil crusts. However, crust removal did not cause significant changes in evaporation compared with the respective soil crust type. These results suggest that the small differences we observed in evaporation among crust types could be caused by differences in the properties of the soil underneath the biological crusts. At low soil moisture (<6%), there was no difference in evaporation among crust types or the underlying soils. Water loss for the complete evaporative cycle (from saturation to dry soil) was similar in both crusted and scraped soils. Therefore, we conclude that for the specific crust and soil types tested, the presence or the type of biological soil crust did not greatly modify evaporation with respect to physical crusts or scraped soils.

  6. Methane emissions from MBT landfills.

    PubMed

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

    2013-09-01

    Within the scope of an investigation for the German Federal Environment Agency ("Umweltbundesamt"), the basics for the estimation of the methane emissions from the landfilling of mechanically and biologically treated waste (MBT) were developed. For this purpose, topical research including monitoring results regarding the gas balance at MBT landfills was evaluated. For waste treated to the required German standards, a methane formation potential of approximately 18-24 m(3)CH(4)/t of total dry solids may be expected. Monitoring results from MBT landfills show that a three-phase model with differentiated half-lives describes the degradation kinetics in the best way. This is due to the fact that during the first years of disposal, the anaerobic degradation processes still proceed relatively intensively. In addition in the long term (decades), a residual gas production at a low level is still to be expected. Most of the soils used in recultivation layer systems at German landfills show a relatively high methane oxidation capacity up to 5 l CH(4)/(m(2)h). However, measurements at MBT disposal sites indicate that the majority of the landfill gas (in particular at non-covered areas), leaves the landfill body via preferred gas emission zones (hot spots) without significant methane oxidation. Therefore, rather low methane oxidation factors are recommended for open and temporarily covered MBT landfills. Higher methane oxidation rates can be achieved when the soil/recultivation layer is adequately designed and operated. Based on the elaborated default values, the First Order Decay (FOD) model of the IPCC Guidelines for National Greenhouse Gas Inventories, 2006, was used to estimate the methane emissions from MBT landfills. Due to the calculation made by the authors emissions in the range of 60,000-135,000 t CO(2-eq.)/a for all German MBT landfills can be expected. This wide range shows the uncertainties when the here used procedure and the limited available data are applied

  7. Transient soil moisture profile of a water-shedding soil cover in north Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Gonzales, Christopher; Baumgartl, Thomas; Scheuermann, Alexander

    2014-05-01

    In current agricultural and industrial applications, soil moisture determination is limited to point-wise measurements and remote sensing technologies. The former has limitations on spatial resolution while the latter, although has greater coverage in three dimensions, but may not be representative of real-time hydrologic conditions of the substrate. This conference paper discusses the use of elongated soil moisture probes to describe the transient soil moisture profile of water-shedding soil cover trial plots in north Queensland, Australia. Three-metre long flat ribbon cables were installed at designed depths across a soil cover with substrate materials from mining activities comprising of waste rocks and blended tailings. The soil moisture measurement is analysed using spatial time domain reflectometry (STDR) (Scheuermann et al., 2009) Calibration of the flat ribbon cable's soil moisture measurement in waste rocks is undertaken in a glasshouse setting. Soil moisture retention and outflows are monitored at specific time interval by mass balance and water potential measurements. These data sets together with the soil hydrologic properties derived from laboratory and field measurements are used as input in the numerical code on unsaturated flow, Hydrus2D. The soil moisture calculations of the glasshouse calibration using this numerical method are compared with results from the STDR soil moisture data sets. In context, the purpose of the soil cover is to isolate sulphide-rich mine wastes from atmospheric interaction as oxidation and leaching of these materials may result to acid and metalliferous drainage. The long term performance of a soil cover will be described in terms of the quantities and physico-chemical characteristics of its outflows. With the soil moisture probes set at automated and pre-determined measurement time intervals, it is expected to distinguish between macropore and soil moisture flows during high intensity rainfall events and, also continuously

  8. Kinetics of biological methane oxidation in the presence of non-methane organic compounds in landfill bio-covers.

    PubMed

    Albanna, Muna; Warith, Mostafa; Fernandes, Leta

    2010-02-01

    In this experimental program, the effects of non-methane organic compounds (NMOCs) on the biological methane (CH4) oxidation process were examined. The investigation was performed on compost experiments incubated with CH4 and selected NMOCs under different environmental conditions. The selected NMOCs had different concentrations and their effects were tested as single compounds and mixtures of compounds. The results from all experimental sets showed a decrease in CH4 oxidation capacity of the landfill bio-cover with the increase in NMOCs concentrations. For example, in the experiment using compost with 100% moisture content at 35 degrees C without any NMOCs the V(max) value was 35.0 microg CH4 h(-1)gwet wt(-1). This value was reduced to 19.1 microg CH4 h(-1) gwet wt(-1) when mixed NMOCs were present in the batch reactors under the same environmental conditions. The experimental oxidation rates of CH4 in the presence of single and mixed NMOCs were modeled using the uncompetitive inhibition model and kinetic parameters, including the dissociation constants, were obtained. Additionally, the degradation rates of the NMOCs and co-metabolic abilities of methanotrophic bacteria were estimated. PMID:19896356

  9. Kinetics of biological methane oxidation in the presence of non-methane organic compounds in landfill bio-covers

    SciTech Connect

    Albanna, Muna; Warith, Mostafa; Fernandes, Leta

    2010-02-15

    In this experimental program, the effects of non-methane organic compounds (NMOCs) on the biological methane (CH{sub 4}) oxidation process were examined. The investigation was performed on compost experiments incubated with CH{sub 4} and selected NMOCs under different environmental conditions. The selected NMOCs had different concentrations and their effects were tested as single compounds and mixtures of compounds. The results from all experimental sets showed a decrease in CH{sub 4} oxidation capacity of the landfill bio-cover with the increase in NMOCs concentrations. For example, in the experiment using compost with 100% moisture content at 35 deg. C without any NMOCs the V{sub max} value was 35.0 mug CH{sub 4}h{sup -1}g{sub wetwt}{sup -1}. This value was reduced to 19.1 mug CH{sub 4}h{sup -1}g{sub wetwt}{sup -1} when mixed NMOCs were present in the batch reactors under the same environmental conditions. The experimental oxidation rates of CH{sub 4} in the presence of single and mixed NMOCs were modeled using the uncompetitive inhibition model and kinetic parameters, including the dissociation constants, were obtained. Additionally, the degradation rates of the NMOCs and co-metabolic abilities of methanotrophic bacteria were estimated.

  10. Carbon storage in a heavy clay soil landfill site after biosolid application.

    PubMed

    Bolan, N S; Kunhikrishnan, A; Naidu, R

    2013-11-01

    Applying organic amendments including biosolids and composts to agricultural land could increase carbon (C) storage in soils and contribute significantly to the reduction of greenhouse gas emissions. Although a number of studies have examined the potential value of biosolids as a soil conditioner and nutrient source, there has been only limited work on the impact of biosolid application on C sequestration in soils. The objective of this study was to examine the potential value of biosolids in C sequestration in soils. Two types of experiments were conducted to examine the effect of biosolid application on C sequestration. In the first laboratory incubation experiment, the rate of decomposition of a range of biosolid samples was compared with other organic amendments including composts and biochars. In the second field experiment, the effect of biosolids on the growth of two bioenergy crops, Brassica juncea (Indian mustard) and Helianthus annuus (sunflower) on a landfill site was examined in relation to biomass production and C sequestration. The rate of decomposition varied amongst the organic amendments, and followed: composts>biosolids>biochar. There was a hundred fold difference in the rate of decomposition between biochar and other organic amendments. The rate of decomposition of biosolids decreased with increasing iron (Fe) and aluminum (Al) contents of biosolids. Biosolid application increased the dry matter yield of both plant species (by 2-2.5 fold), thereby increasing the biomass C input to soils. The rate of net C sequestration resulting from biosolid application (Mg C ha(-1) yr(-1) Mg(-1) biosolids) was higher for mustard (0.103) than sunflower (0.087). Biosolid application is likely to result in a higher level of C sequestration when compared to other management strategies including fertilizer application and conservation tillage, which is attributed to increased microbial biomass, and Fe and Al oxide-induced immobilization of C. PMID:23380138

  11. Living cover crops have immediate impacts on soil microbial community structure and function

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover cropping is a widely promoted strategy to enhance soil health in agricultural systems. Despite a substantial body of literature demonstrating links between cover crops and soil biology, an important component of soil health, research evaluating how specific cover crop species influence soil mi...

  12. Enhancing cleanup of heavy metal-polluted landfill soils and improving soil microbial activity using green technology with ferrous sulfate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Landfills have led to some of the most intense battles over pollution that has ever been seen. With the population skyrocketing worldwide, these landfills will only become more of a public issue as time goes on. Heavy metals from several sources especially in landfills are an increasingly urgent pro...

  13. Replacing fallow with cover crops in a semiarid soil:Effects on soil properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Replacement of fallow in crop–fallow systems with cover crops (CCs) may improve soil properties. We assessed whether replacing fallow in no-till winter wheat (Triticum aestivum L.)–fallow with winter and spring CCs for 5 years reduced wind and water erosion, increased soil organic carbon (SOC), and ...

  14. Replacing fallow with cover crops in a semiarid soil: effects on soil properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Replacement of fallow in crop-fallow systems with cover crops (CCs) may improve soil properties. We assessed whether replacing fallow in no-till winter wheat (Triticum aestivum L.)-fallow with winter and spring CCs for five years reduced wind and water erosion, increased soil organic carbon (SOC), a...

  15. Fate and distribution of nitrogen in soil and plants irrigated with landfill leachate.

    PubMed

    Cheng, C Y; Chu, L M

    2011-06-01

    Landfill leachate contains a high concentration of ammoniacal substances which can be a potential supply of N for plants. A bioassay was conducted using seeds of Brassica chinensis and Lolium perenne to evaluate the phytotoxicity of the leachate sample. A soil column experiment was then carried out in a greenhouse to study the effect of leachate on plant growth. Two grasses (Paspalum notatum and Vetiver zizanioides) and two trees (Hibiscus tiliaceus and Litsea glutinosa) were irrigated with leachate at the EC50 levels for 12 weeks. Their growth performance and the distribution of N were examined and compared with columns applied with chemical fertilizer. With the exception of P. notatum, plants receiving leachate and fertilizer grew better than those receiving water alone. The growth of L. glutinosa and V. zizanioides with leachate irrigation did not differ significantly from plants treated with fertilizer. Leachate irrigation significantly increased the levels of NH(x)-N in soil. Although NO(x)-N was below 1 mg NL(-1) in the leachate sample, the soil NO(x)-N content increased by 9-fold after leachate irrigation, possibly as a result of nitrification. Leachate irrigation at EC50 provided an N input of 1920 kg N ha(-1) over the experimental period, during which up to 1050 kg N ha(-1) was retained in the soil and biomass, depending on the type of vegetation. The amount of nutrient added seems to exceed beyond the assimilative capability. Practitioners should be aware of the possible consequence of N saturation when deciding the application rate if leachate irrigation is aimed for water reuse. PMID:21349695

  16. Space monitoring of municipal solid waste landfills in Kazakhstan

    NASA Astrophysics Data System (ADS)

    Skakova, Olga; Shagarova, Lyudmila

    Municipal solid waste (MSW) landfills are special facilities designed for waste isolation and disposal ensuring sanitary and epidemiological safety of population. A solid waste landfill is a complex object with its own specific features. Modern remote-sensing methods are an indispensable source of information for the analysis of space images of solid waste landfills in Kazakhstan. Space monitoring of solid waste landfills includes the following tasks: 1. Identification and mapping of landfill areas according to the data of remote earth sensing. 2. Studying of energy and structural characteristics of landfills based on remote sensing data. 3. Analysis of the state of landfills based on a comparison of current and archive remote sensing data. Space monitoring of territories of municipal solid waste landfills uses modern computer technologies. They include satellite imagery combined with sub-satellite research, as well as other sources of information used for identification and mapping of landfill territories. Investigation of municipal solid waste landfills requires targeted survey of landfill areas, remote sensing using operational and archival data including theoretical foundations of physical optics and statistical data. Processing of digital satellite information uses methods of pattern recognition, automated image processing and correlation analysis. Based on spectral energy and textural characteristics of municipal solid waste landfills obtained by remote sensing methods, the technology of space monitoring of landfill areas, including landfill recognition and characterization of solid waste landfills from remote observations was developed. Monitoring of MSW landfills uses satellite images of ultrahigh and medium spatial resolution. Medium-resolution images are used to determine temperature, vegetation cover and soil degradation. High-resolution images are used to detect landfills, to determine forms of soil degradation, to calculate geometrical parameters, and

  17. Land cover changes and greenhouse gas emissions in two different soil covers in the Brazilian Caatinga.

    PubMed

    Ribeiro, Kelly; Sousa-Neto, Eráclito Rodrigues de; Carvalho, João Andrade de; Sousa Lima, José Romualdo de; Menezes, Rômulo Simões Cezar; Duarte-Neto, Paulo José; da Silva Guerra, Glauce; Ometto, Jean Pierre Henry Baulbaud

    2016-11-15

    The Caatinga biome covers an area of 844,453km(2) and has enormous endemic biodiversity, with unique characteristics that make it an exclusive Brazilian biome. It falls within the earth's tropical zone and is one of the several important ecoregions of Brazil. This biome undergoes natural lengthy periods of drought that cause losses in crop and livestock productivity, having a severe impact on the population. Due to the vulnerability of this ecosystem to climate change, livestock has emerged as the main livelihood of the rural population, being the precursor of the replacement of native vegetation by grazing areas. This study aimed to measure GHG emissions from two different soil covers: native forest (Caatinga) and pasture in the municipality of São João, Pernambuco State, in the years 2013 and 2014. GHG measurements were taken by using static chamber techniques in both soil covers. According to a previous search, so far, this is the first study measuring GHG emissions using the static chamber in the Caatinga biome. N2O emissions ranged from -1.0 to 4.2mgm(-2)d(-1) and -1.22 to 3.4mgm(-2)d(-1) in the pasture and Caatinga, respectively, and they did not significantly differ from each other. Emissions were significantly higher during dry seasons. Carbon dioxide ranged from -1.1 to 14.1 and 1.2 to 15.8gm(-2)d(-1) in the pasture and Caatinga, respectively. CO2 emissions were higher in the Caatinga in 2013, and they were significantly influenced by soil temperature, showing an inverse relation. Methane emission ranged from 6.6 to 6.8 and -6.0 to 4.8mgm(-2)d(-1) in the pasture and Caatinga, respectively, and was significantly higher only in the Caatinga in the rainy season of 2014. Soil gas fluxes seemed to be influenced by climatic and edaphic conditions as well as by soil cover in the Caatinga biome. PMID:27453133

  18. Vegetation study in support of the design and optimization of vegetative soil covers, Sandia National Laboratories, Albuquerque, New Mexico.

    SciTech Connect

    Peace, Gerald L.; Goering, Timothy James (GRAM inc., Albuquerque, NM); Knight, Paul J. (Marron and Associates, Albuquerque, NM); Ashton, Thomas S. (Marron and Associates, Albuquerque, NM)

    2004-11-01

    A vegetation study was conducted in Technical Area 3 at Sandia National Laboratories, Albuquerque, New Mexico in 2003 to assist in the design and optimization of vegetative soil covers for hazardous, radioactive, and mixed waste landfills at Sandia National Laboratories/New Mexico and Kirtland Air Force Base. The objective of the study was to obtain site-specific, vegetative input parameters for the one-dimensional code UNSAT-H and to identify suitable, diverse native plant species for use on vegetative soil covers that will persist indefinitely as a climax ecological community with little or no maintenance. The identification and selection of appropriate native plant species is critical to the proper design and long-term performance of vegetative soil covers. Major emphasis was placed on the acquisition of representative, site-specific vegetation data. Vegetative input parameters measured in the field during this study include root depth, root length density, and percent bare area. Site-specific leaf area index was not obtained in the area because there was no suitable platform to measure leaf area during the 2003 growing season due to severe drought that has persisted in New Mexico since 1999. Regional LAI data was obtained from two unique desert biomes in New Mexico, Sevilletta Wildlife Refuge and Jornada Research Station.

  19. Calculations of radar backscattering coefficient of vegetation-covered soils

    NASA Technical Reports Server (NTRS)

    Mo, T.; Schmugge, T. J.; Jackson, T. J. (Principal Investigator)

    1983-01-01

    A model for simulating the measured backscattering coefficient of vegetation-covered soil surfaces includes both coherent and incoherent components of the backscattered radar pulses from a rough sil surface. The effect of vegetation canopy scattering is also incorporated into the model by making the radar pulse subject to two-way attenuation and volume scattering when it passes through the vegetation layer. Model results agree well with the measured angular distributions of the radar backscattering coefficient for HH polarization at the 1.6 GHz and 4.75 GHz frequencies over grass-covered fields. It was found that the coherent scattering component is very important at angles near nadir, while the vegetation volume scattering is dominant at incident angles 30 degrees.

  20. Effect of soil properties and a synthetic municipal landfill leachate on the retention of Cd, Ni, Pb, and Zn in soil and sediment materials

    SciTech Connect

    LaBauve, J.M.; Kotuby-Amacher, J.; Gambrell, R.P.

    1988-03-01

    Batch equilibrium metal immobilization studies were conducted using seven soils and sediment materials spiked with varying concentrations of Cd, Ni, Pb, and Zn. The objective was to examine the potential mobility of metals in subsoils of metals-contaminated sites. Soil pH influenced metal immobilization more than other properties. The inclusion of other property values improved correlation of retention and concentration. Among the metals, Pb was most strongly retained, while Ni was the most mobile. The presence of a synthetic municipal landfill leachate enhanced the dissolved levels of two metals studied (Cd, Ni) in all soil materials.

  1. Magnetic, geo-electric, and groundwater and soil quality analysis over a landfill from a lead smelter, Cairo, Egypt

    NASA Astrophysics Data System (ADS)

    Khalil, Mohamed H.

    2012-11-01

    A detailed ground magnetic survey, geoelectric vertical electric sounding (VES), and groundwater and soil quality analysis were conducted in the area of the abandoned landfill of the Awadallah lead (Pb) smelter, northeastern Cairo, Egypt. The integration between the applied techniques located successfully the buried solid waste, demarcated the groundwater and its possible contamination, and determined the lead level in soil. Magnetic survey comprised 50 magnetic profiles each 190 m length. Vertical derivatives, wavelength filters, and continuation filters characterized the eastern and central parts of the landfill by high intense magnetic anomalies reflecting metal and lead wastes, whereas the western part was characterized by low intense anomalies indicating change in the landfill composition to non-magnetized material. The geoelectric survey comprised 16 VES with a maximum AB/2 of 100 m. The inverted data demarcated effectively the groundwater aquifer with depth ranged from 11 to 18 m and true resistivities ranged from 96 to 118 Ω·m. The second layer (Holocene-Q3) of semi-permeable silty and sandy clay cap (true resistivities 29 ~ 51 Ω·m and thickness 9-17 m) constituted a considerable role in limiting the possible contamination from the landfill. The analyzed groundwater parameters pH, Eh, TDS, SEC, and DO indicated a good water quality with homogenous aquifer characteristics, whereas the lead concentration in groundwater (0.033-0.036 mg/L) was slightly exceeding the safe limits identified by the U.S. EPA (≤ 0.015 mg/L). Lead in soil samples revealed elevated concentrations (3130 mg/L/kg at VES-3) around the Awadallah smelter, whereas a gradual decrease in concentrations was recorded in the northwestern direction.

  2. Application of ecological risk assessment based on a novel TRIAD-tiered approach to contaminated soil surrounding a closed non-sealed landfill.

    PubMed

    Gutiérrez, Laura; Garbisu, Carlos; Ciprián, Estela; Becerril, José M; Soto, Manu; Etxebarria, Javier; Madariaga, Juan M; Antigüedad, Iñaki; Epelde, Lur

    2015-05-01

    The Ecological Risk Assessment (ERA) is a reliable tool for communicating risk to decision makers in a comprehensive and scientific evidence-based way. In this work, a site-specific ERA methodology based on the TRIAD approach was applied to contaminated soil surrounding a closed non-sealed landfill, as a case study to implement and validate such ERA methodology in the Basque Country (northern Spain). Initially, the procedure consisted of the application of a Parameter Selection Module aimed at selecting the most suitable parameters for the specific characteristics of the landfill contaminated soil, taking into consideration the envisioned land use, intended ecosystem services and nature of contaminants. Afterwards, the selected parameters were determined in soil samples collected from two sampling points located downstream of the abovementioned landfill. The results from these tests were normalized to make them comparable and integrable in a risk index. Then, risk assessment criteria were developed and applied to the two landfill contaminated soil samples. Although the lack of a proper control soil was evidenced, a natural land use was approved by the ERA (at Tier 2) for the two landfill contaminated soils. However, the existence of a potential future risk resulting from a hypothetical soil acidification must be considered. PMID:25659305

  3. Controls on Watershed Biogeochemistry by Climate, Land Cover, and Soils

    NASA Astrophysics Data System (ADS)

    Fisher, T. R.; Sutton, A. J.; Gustafson, A. B.; Koskelo, A. I.; Fox, R. J.; Stone, J.

    2006-05-01

    Water and elemental discharge from catchments is largely controlled by climate, soils, and land cover. Seasonal temperature and rainfall patterns determine the water available for stream discharge, and average annual air temperature is inversely correlated with the proportion of rainfall that is annually discharged as stream flow. At higher temperatures, an increasing fraction of the soil water is evapotranspired to the atmosphere as water vapor rather than discharged as stream flow. Hydrologic soil drainage properties determine whether precipitation is primarily directed horizontally as overland flow or vertically as infiltration to groundwater for baseflow. Concentrations of N in groundwater, primarily nitrate, reflect the surface land uses, particularly agriculture and residential areas with septic systems. However, hydric soils act as a trap for anthropogenic nitrate in groundwater, probably by denitrification in oxygen-poor, C-rich, micro-environments. Likewise, the P content of surface soils controls the P concentration in overland flow due to leaching of soluble P and erosion of particulate P. At the watershed scale, concentrations of N and P in stream discharge are augmented in proportion to the fraction of the basin in anthropogenic land uses such as agriculture and urban areas, which contribute nutrients via application of fertilizers and disposal of human waste. This anthropogenic fraction of a basin's land uses represents the human footprint upon the land which primarily determines the elevated N and P losses from the basin. N is relatively easily sampled because it is primarily transported as highly soluble nitrate in groundwater-supported baseflow; however, P sampling is more difficult because transport largely occurs episodically following storm events when both stream flow and P concentrations are high during brief periods. As a result, P concentrations and fluxes are almost certainly undersampled and underestimated compared to N fluxes, and fewer

  4. A statistical model for landfill surface emissions.

    PubMed

    Héroux, Martin; Guy, Christophe; Millette, Denis

    2010-02-01

    Landfill operators require a rapid, simple, low-cost, and accurate method for estimation of landfill methane surface emissions over time. Several methods have been developed to obtain instantaneous field measurements of landfill methane surface emissions. This paper provides a methodology for interpolating instantaneous measurements over time, taking variations in meteorological conditions into account. The goal of this study was to determine the effects of three factors on landfill methane surface emissions: air temperature, pressure gradient between waste and atmosphere, and soil moisture content of the cover material. On the basis of a statistical three-factor and two-level full factorial design, field measurements of methane emissions were conducted at the City of Montreal landfill site during the summer of 2004. Three areas were measured: test area 1 (4800 m2), test area 2 (1400 m2), and test area 3 (1000 m2). Analyses of variance were performed on the data. They showed a significant statistical effect of the three factors and the interaction between temperature and soil moisture content on methane emissions. Analysis also led to the development of a multifactor correlation, which can be explained by the underlying processes of diffusive and advective flow and biological oxidation. This correlation was used to estimate total emissions of the three test areas for July and August 2004. The approach was validated using a second dataset for another area adjacent to the landfill. PMID:20222535

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

    PubMed

    Kim, Kwon-Rae; Owens, Gary

    2010-01-01

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

  6. [Effects of seasonal snow cover on soil nitrogen transformation in alpine ecosystem: a review].

    PubMed

    Liu, Lin; Wu, Yan; He, Yi-xin; Wu, Ning; Sun, Geng; Zhang, Lin; Xu, Jun-jun

    2011-08-01

    Seasonal snow cover has pronounced effects on the soil nitrogen concentration and transformation in alpine ecosystem. Snowfall is an important form of nitrogen deposition, which directly affects the content of soil available nitrogen. Different depths and different duration of snow cover caused by snowfall may lead the heterogeneity of abiotic factors (soil temperature and moisture) and biotic factors (soil microbes, alpine plants, and alpine animals), and further, produce complicated effects on the mineralization and immobilization of soil nitrogen. This paper introduced in emphasis the inherent mechanisms of soil nitrogen mineralization and leaching under the effects of frequent freeze-thaw events during the durative melting of snow cover, and summarized the main research results of field in situ experiments about the effects of seasonal snow cover on soil nitrogen in alpine ecosystem based on the possible changes in snow cover in the future. Some suggestions with regard to the effects of seasonal snow cover on soil nitrogen were put forward. PMID:22097387

  7. Estonian soil classification as a tool for recording information on soil cover and its matching with local site types, plant covers and humus forms classifications

    NASA Astrophysics Data System (ADS)

    Kõlli, Raimo; Tõnutare, Tõnu; Rannik, Kaire; Krebstein, Kadri

    2015-04-01

    Estonian soil classification (ESC) has been used successfully during more than half of century in soil survey, teaching of soil science, generalization of soil databases, arrangement of soils sustainable management and others. The Estonian normally developed (postlithogenic) mineral soils (form 72.4% from total area) are characterized by mean of genetic-functional schema, where the pedo-ecological position of soils (ie. location among other soils) is given by means of three scalars: (i) 8 stage lithic-genetic scalar (from rendzina to podzols) separates soils each from other by parent material, lithic properties, calcareousness, character of soil processes and others, (ii) 6 stage moisture and aeration conditions scalar (from aridic or well aerated to permanently wet or reductic conditions), and (iii) 2-3 stage soil development scalar, which characterizes the intensity of soil forming processes (accumulation of humus, podzolization). The organic soils pedo-ecological schema, which links with histic postlithogenic soils, is elaborated for characterizing of peatlands superficial mantle (form 23.7% from whole soil cover). The position each peat soil species among others on this organic (peat) soil matrix schema is determined by mean of 3 scalars: (i) peat thickness, (ii) type of paludification or peat forming peculiarities, and (iii) stage of peat decomposition or peat type. On the matrix of abnormally developed (synlithogenic) soils (all together 3.9%) the soil species are positioned (i) by proceeding in actual time geological processes as erosion, fluvial processes (at vicinity of rivers, lakes or sea) or transforming by anthropogenic and technological processes, and (ii) by 7 stage moisture conditions (from aridic to subaqual) of soils. The most important functions of soil cover are: (i) being a suitable environment for plant productivity; (ii) forming adequate conditions for decomposition, transformation and conversion of falling litter (characterized by humus

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

    USGS Publications Warehouse

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

    2011-01-01

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

  9. Amending metal contaminated mine soil with biochars to sequester metals and improve plant growth cover

    EPA Science Inventory

    There are numerous mine spoil sites in the U.S. Pacific Northwest that contain highly acidic, heavy metal-laden soils, which limits establishment of a soil-stabilizing plant cover. Biochars may be a suitable soil amendment to reduce toxic metals, improve soil fertility, soil wa...

  10. Comparison of two numerical modelling approaches to a field experiment of unsaturated radon transport in a covered uranium mill tailings soil (Lavaugrasse, France).

    PubMed

    Saâdi, Zakaria; Guillevic, Jérôme

    2016-01-01

    Uncertainties on the mathematical modelling of radon ((222)Rn) transport in an unsaturated covered uranium mill tailings (UMT) soil at field scale can have a great impact on the estimation of the average measured radon exhalation rate to the atmosphere at the landfill cover. These uncertainties are usually attributed to the numerical errors from numerical schemes dealing with soil layering, and to inadequate modelling of physical processes at the soil/plant/atmosphere interface and of the soil hydraulic and transport properties, as well as their parameterization. In this work, we demonstrate how to quantify these uncertainties by comparing simulation results from two different numerical models to experimental data of radon exhalation rate and activity concentration in the soil-gas measured in a covered UMT-soil near the landfill site Lavaugrasse (France). The first approach is based on the finite volume compositional (i.e., water, radon, air) transport model TOUGH2/EOS7Rn (Transport Of Unsaturated Groundwater and Heat version 2/Equation Of State 7 for Radon; Saâdi et al., 2014), while the second one is based on the finite difference one-component (i.e., radon) transport model TRACI (Transport de RAdon dans la Couche Insaturée; Ferry et al., 2001). Transient simulations during six months of variable rainfall and atmospheric air pressure showed that the model TRACI usually overestimates both measured radon exhalation rate and concentration. However, setting effective unsaturated pore diffusivities of water, radon and air components in soil-liquid and gas to their physical values in the model EOS7Rn, allowed us to enhance significantly the modelling of these experimental data. Since soil evaporation has been neglected, none of these two models was able to simulate the high radon peaks observed during the dry periods of summer. However, on average, the radon exhalation rate calculated by EOS7Rn was 34% less than that was calculated by TRACI, and much closer to the

  11. Soils and the soil cover of the taiga zone in the northern Urals (upper reaches of the Pechora River)

    NASA Astrophysics Data System (ADS)

    Semikolennykh, A. A.; Bovkunov, A. D.; Aleinikov, A. A.

    2013-08-01

    The territory in the upper reaches of the Pechora River is characterized by the predominance of Al-Fe-humus and metamorphic soils with gley features developing under the middle taiga fir-spruce forests rather than gley-podzolic soils as had been considered before. Some of the described soil profiles represent intergrades between brown taiga soils (burozems) and gleysols; these soils are absent in the new Russian soil classification system. General regularities of the soil cover are controlled by the geomorphic position of the soils on slopes and by the conditions of ground moistening and lateral soil water flows. The development of modern soil cover patterns is determined by the impact of herbaceous and woody vegetation, bioturbation of the soils by windfalls, the presence of dead tree trunks on the soil surface, and other factors.

  12. Environmental polychlorinated biphenyls: acute toxicity of landfill soil extract to female prepubertal rats.

    PubMed

    Hansen, L G; Li, M H; Saeed, A; Bush, B

    1995-10-01

    Subsurface soil from a National Priorities List landfill containing about 2.5% polychlorinated biphenyls (PCBs) was extracted and the extract cleaned by Florisil slurry and alumina column chromatography. The refined extract contained 48 mg/mL PCB, mainly trichlorobiphenyls and tetrachlorobiphenyls, traces of polychlorinated naphthalenes, 125 micrograms/mL 2,2-bis-p-chlorophenyl-1,1-dichloroethylene (DDE), and low levels of chlorinated dibenzofurans. The refined extract was dissolved in corn oil and administered intraperitoneally to weanling (day 20) female rats on days 20 and 21; rats were terminated on day 22. Limited data indicated possible hematopoietic effects, including neutrophilia. There were no changes in relative uterus, kidney, or adrenal gland weights between total doses of 3 to 96 mg/kg total PCB. Relative liver weights increased significantly at 36 mg/kg and activities of P450s 1A1 (as ethoxyresorufin O-dealkylase) and 2B (as pentoxyresorufin O-dealkylase) increased at 12 mg/kg and plateaued at 36 (P450 1A1) or 48 (P450 2b) mg/kg. Serum total thyroxine (T4) declined significantly at doses of 36 mg/kg and greater; thyroid follicular epithelial cells were significantly larger within the same dose range, but the follicular colloid area decreased to less than 60% control values at 12 mg/kg and remained at this size through 72 mg/kg. Maximum mobilization of T4 apparently occurred at 12 mg/kg and attenuated measured declines in circulating levels. Even though a large proportion of proven and probable estrogenic chlorobiphenyls (CBs) were present, the lower amounts of more potent antiestrogenic aryl hydrocarbon (Ah) receptor agonists and/or decreased responsiveness because of low serum T4 levels may have antagonized the uterotropic response. PMID:7487157

  13. COVER CROPS ENHANCE SOIL ORGANIC MATTER, CARBON DYNAMICS AND MICROBIOLOGICAL FUNCTION IN A MEDITERRANEAN VINEYARD AGROECOSYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Impacts of soil tillage and cover crops on soil carbon (C) dynamics and microbiological function were investigated in a vineyard grown in California’s Mediterranean climate. We 1) compared soil organic matter (SOM), C dynamics and microbiological activity of two cover crops [Trios 102 (Triticale x T...

  14. Land Cover Differences in Soil Carbon and Nitrogen at Fort Benning, Georgia

    SciTech Connect

    Garten Jr., C.T.

    2004-02-09

    Land cover characterization might help land managers assess the impacts of management practices and land cover change on attributes linked to the maintenance and/or recovery of soil quality. However, connections between land cover and measures of soil quality are not well established. The objective of this limited investigation was to examine differences in soil carbon and nitrogen among various land cover types at Fort Benning, Georgia. Forty-one sampling sites were classified into five major land cover types: deciduous forest, mixed forest, evergreen forest or plantation, transitional herbaceous vegetation, and barren land. Key measures of soil quality (including mineral soil density, nitrogen availability, soil carbon and nitrogen stocks, as well as properties and chemistry of the O-horizon) were significantly different among the five land covers. In general, barren land had the poorest soil quality. Barren land, created through disturbance by tracked vehicles and/or erosion, had significantly greater soil density and a substantial loss of carbon and nitrogen relative to soils at less disturbed sites. We estimate that recovery of soil carbon under barren land at Fort Benning to current day levels under transitional vegetation or forests would require about 60 years following reestablishment of vegetation. Maps of soil carbon and nitrogen were produced for Fort Benning based on a 1999 land cover map and field measurements of soil carbon and nitrogen stocks under different land cover categories.

  15. Soil carbon accumulation after short-term use of rye as a winter cover crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of winter cover crops has been proposed to protect and enhance soil resources. Cereal rye (Secale cereale L.) can be an effective cover crop since it can produce large amounts of biomass in certain climates. However, short-term benefits of cover crop use on soil carbon accumulation are not w...

  16. Soil organic carbon and water content effects on remote crop residue cover estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation tillage (CT) systems help protect the soil and environment, and improve net farm profitability. CT methods leave increased amounts of crop residue cover (CRC) on the soil surface, minimizing soil erosion and evaporation. CT uses less fuel, disturbs soil less, and requires less fertili...

  17. The Challenges of Implementing Conservation Tillage and Cover Crops in Clay Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation practices, such as reduced tillage and cover crops, can improve soil quality and increase soil moisture for crop production. Benefits to production, soil quality, and water conservation have been observed especially in areas with rapidly draining soils. While historically enjoying high ...

  18. Fall cover crops boost soil arbuscular mycorrhizal fungi which can lead to reduced inputs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fall cover crops provide multiple benefits to producers. These benefits include pathogen and pest protection, drought protection, weed control, reduced soil erosion, nutrient acquisition and retention, increased soil organic matter, and conservation of soil water by improvement of soil structure th...

  19. Functional and environmental assessment of the urboecosystems designed in the biologically reclamated landfill with industrial wastes (in Ryazan city)

    NASA Astrophysics Data System (ADS)

    Karyakin, Alexey; Vasenev, Ivan; Karyakina, Svetlana

    2015-04-01

    Regional environmental bodies' ability to understand, model and predict their soil cover environmental functions are especially important in case of landfill reclamation. The special attention has to be done to landfills with industrial wastes created earlier in frame of big city - comparatively closed to their residential areas. Dominated in Ryazan region sandy loam gray forest soils with not so high soil organic matter content and soil exchange capacity determine additional problems with landfill biological reclamation and continuous sustainable vegetation cover development. The modern environmental monitoring system has been developed in the big landfill with tanning industrial wastes from the biggest in Europe tannery to develop recommendation on the environmentally friendly reclamation technologies adapted to concrete landscape conditions and functional features of 2 m fresh soil-ground coating the landfill surface. More detailed monitoring system has to be developed to assess the regulatory environmental functions of the regenerated soil cover to minimize the reclamated landfill' negative impacts on the urban ecosystem air, surface and ground water quality. Obtained result will be useful for similar landfills with tanning industrial wastes environmental impact assessment and smart design.

  20. Land cover heterogeneity and soil respiration in a west Greenland tundra landscape

    NASA Astrophysics Data System (ADS)

    Bradley-Cook, J. I.; Burzynski, A.; Hammond, C. R.; Virginia, R. A.

    2011-12-01

    Multiple direct and indirect pathways underlie the association between land cover classification, temperature and soil respiration. Temperature is a main control of the biological processes that constitute soil respiration, yet the effect of changing atmospheric temperatures on soil carbon flux is unresolved. This study examines associations amongst land cover, soil carbon characteristics, soil respiration, and temperature in an Arctic tundra landscape in western Greenland. We used a 1.34 meter resolution multi-spectral WorldView2 satellite image to conduct an unsupervised multi-staged ISODATA classification to characterize land cover heterogeneity. The four band image was taken on July 10th, 2010, and captures an 18 km by 15 km area in the vicinity of Kangerlussuaq. The four major terrestrial land cover classes identified were: shrub-dominated, graminoid-dominated, mixed vegetation, and bare soil. The bare soil class was comprised of patches where surface soil has been deflated by wind and ridge-top fellfield. We hypothesize that soil respiration and soil carbon storage are associated with land cover classification and temperature. We set up a hierarchical field sampling design to directly observe spatial variation between and within land cover classes along a 20 km temperature gradient extending west from Russell Glacier on the margin of the Greenland Ice Sheet. We used the land cover classification map and ground verification to select nine sites, each containing patches of the four land cover classes. Within each patch we collected soil samples from a 50 cm pit, quantified vegetation, measured active layer depth and determined landscape characteristics. From a subset of field sites we collected additional 10 cm surface soil samples to estimate soil heterogeneity within patches and measured soil respiration using a LiCor 8100 Infrared Gas Analyzer. Soil respiration rates varied with land cover classes, with values ranging from 0.2 mg C/m^2/hr in the bare soil

  1. Summer cover crops and soil amendments to improve growth and nutrient uptake of okra

    SciTech Connect

    Wang, Q.R.; Li, Y.C.; Klassen, W.

    2006-04-15

    A pot experiment with summer cover crops and soil amendments was conducted in two consecutive years to elucidate the effects of these cover crops and soil amendments on 'Clemson Spineless 80' okra (Abelmoschus esculentus) yields and biomass production, and the uptake and distribution of soil nutrients and trace elements. The cover crops were sunn hemp (Crotalaria juncea), cowpea (Vigna unguiculata), velvetbean (Mucuna deeringiana), and sorghum sudan-grass (Sorghum bicolor x S. bicolor var. sudanense) with fallow as the control. The organic soil amendments were biosolids (sediment from wastewater plants), N-Viro Soil (a mixture of biosolids and coal ash), coal ash (a combustion by-product from power plants), co-compost (a mixture of 3 biosolids: 7 yard waste), and yard waste compost (mainly from leaves and branches of trees and shrubs, and grass clippings) with a soil-incorporated cover crop as the control. As a subsequent vegetable crop, okra was grown after the cover crops, alone or together with the organic soil amendments, had been incorporated. All of the cover crops, except sorghum sudangrass in 2002-03, significantly improved okra fruit yields and the total biomass production. Both cover crops and soil amendments can substantially improve nutrient uptake and distribution. The results suggest that cover crops and appropriate amounts of soil amendments can be used to improve soil fertility and okra yield without adverse environmental effects or risk of contamination of the fruit. Further field studies will be required to confirm these findings.

  2. Analysis of instantaneous profile test data from soils near the Mixed Waste Landfill, Technical Area 3, Sandia National Laboratories/New Mexico

    SciTech Connect

    Goering, T.J.; McVey, M.D.; Strong, W.R.; Peace, J.L.

    1996-02-01

    This paper presents the results of an instantaneous profile test conducted near the Mixed Waste Landfill at Sandia National Laboratories/New Mexico. The purpose of the test was to measure the unsaturated hydraulic properties of soils near the Mixed Waste Landfill, including the relations between hydraulic conductivity, moisture content, and soil water tension. A 4.7 meter by 4.7 meter plot was saturated with water to a depth of 2 meters, and the wetting and drying responses of the vertical profile were observed. These data were analyzed to obtain in situ measurements of the unsaturated hydraulic properties.

  3. The effects of different soil cover management practices on plant biodiversity and soil properties in Mediterranean ancient olive orchards

    NASA Astrophysics Data System (ADS)

    Madzaric, Suzana; Aly, Adel; Ladisa, Gaetano; Calabrese, Generosa

    2014-05-01

    The effects of different soil cover management practices on plant biodiversity and soil properties in Mediterranean ancient olive orchards Madzaric S., Aly A., Ladisa G. and Calabrese G. The loss of natural plant cover due to the inappropriate soil cover management is often a decisive factor for soil degradation in Mediterranean area. This accompanied with typical climate, characterized by cool, wet winters and hot and dry summers leads to soil erosion and loss of productivity. Due to simplification of agricultural practice and to the attempt to decrease cost of production, keeping soil bare is a widespread agricultural practice in Mediterranean ancient olive orchards (AOOs). The consequences of this are degradation of soil quality and reduction of plant biodiversity. In last year's some alternative practices are proposed in order to protect soil and biodiversity. One of these practices is the "grassing" i.e. covering the soil by selected autochthonous plant species. Objectives of our study are: (1) to evaluate impact of different soil cover management practices on soil properties and plant biodiversity in AOOs and (2) to define a minimum indicators' set (Minimum Data Set - MDS) to evaluate the effectiveness of different agricultural practices in environmental performance of AOOs. A comparison was carried on considering two management systems (conventional vs. organic) and three agricultural practices: conventional with bare soil (CON), organic with soil covered by selected autochthonous species (MIX) and organic left to the native vegetation (NAT). In general a clear positive influence of organic management system was recognized. Some soil quality indicators (physical, chemical and biological) showed responsiveness in describing the effects of management system and agricultural practices on soil properties. The both approaches with vegetation cover on the soil surface (either sowing of mixture or soil left to the natural plant cover) performed better than

  4. Mobility of Pb, Cu, and Zn in the phosphorus-amended contaminated soils under simulated landfill and rainfall conditions.

    PubMed

    Cao, Xinde; Liang, Yuan; Zhao, Ling; Le, Huangying

    2013-09-01

    Phosphorus-bearing materials have been widely applied in immobilization of heavy metals in contaminated soils. However, the study on the stability of the initially P-induced immobilized metals in the contaminated soils is far limited. This work was conducted to evaluate the mobility of Pb, Cu, and Zn in two contrasting contaminated soils amended with phosphate rock tailing (PR) and triple superphosphate fertilizer (TSP), and their combination (P + T) under simulated landfill and rainfall conditions. The main objective was to determine the stability of heavy metals in the P-treated contaminated soils in response to the changing environment conditions. The soils were amended with the P-bearing materials at a 2:1 molar ratio of P to metals. After equilibrated for 2 weeks, the soils were evaluated with the leaching procedures. The batch-based toxicity characteristic leaching procedure (TCLP) was conducted to determine the leachability of heavy metals from both untreated and P-treated soils under simulated landfill condition. The column-based synthetic precipitation leaching procedure (SPLP) were undertaken to measure the downward migration of metals from untreated and P-treated soils under simulated rainfall condition. Leachability of Pb, Cu, and Zn in the TCLP extract followed the order of Zn > Cu > Pb in both soils, with the organic-C- and clay-poor soil showing higher metal leachability than the organic-C- and clay-rich soil. All three P treatments reduced leachability of Pb, Cu, and Zn by up to 89.2, 24.4, and 34.3 %, respectively, compared to the untreated soil, and TSP revealed more effectiveness followed by P + T and then PR. The column experiments showed that Zn had the highest downward migration upon 10 pore volumes of SPLP leaching, followed by Pb and then Cu in both soils. However, migration of Pb and Zn to subsoil and leachate were inhibited in the P-treated soil, while Cu in the leachate was enhanced by P treatment in the organic

  5. What's left? - Investigations on soil cover of conservation tillage methods in Austria

    NASA Astrophysics Data System (ADS)

    Bauer, Thomas; Hösl, Rosemarie; Strauss, Peter

    2014-05-01

    One of the most accepted and a practicable method to prevent soil from erosion is conservation tillage. If conservation tillage practices are performed in a proper way soil is protected from wind and water erosion. This study deals with the effectivity of conservation tillage practices under real field conditions. Therefore we i) carried out rainfall simulation experiments employing conservation tillage practices which had been proposed by farmers to test whether actual conservation tillage practices would be effective, ii) did an observation of mean soil cover on arable land after seeding in Lower and Upper Austria for field sites where conservation tillage was funded. Rainfall simulation experiments were carried out in the years 2011 and 2012 for various conservation tillage treatments consisting of different mulching and no tillage techniques. To evaluate results on surface runoff and erosion we additionally measured soil cover, bulk densities and surface roughness of the experimental plots. Soil cover estimation of the arable land in Lower and Upper Austria which is funded for conservation tillage practices was done in 2012 and 2013. Altogether on 146 randomly chosen field sites soil cover was estimated by using an object-based image analysis method. Results reveal that the effectiveness of conservation tillage was depending on the existence of a sufficient soil cover. However, under conditions of actual farm practices, a sufficient soil cover was not obtained for mulching treatments in 2011 and only partially in 2012. Therefore, mulching treatments partially gained even higher surface runoff and soil loss rates than conventional tillage practices. Due to their high soil cover, soil loss and surface runoff of no tillage treatments were very small as compared to all other tested treatments. The results of the soil cover estimation in Lower and Upper Austria show that under practicable land use a mean soil cover of 12 percent can be reached, what's rather low in

  6. Cover Crop Effects on the Fate of Swine Manure-N Applied to Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cereal grain cover crops increase surface cover, anchor corn and soybean residues, increase infiltration, reduce both rill and interrill erosion, scavenge excess nutrients from the soil, and are easily obtained and inexpensive compared to other cover crop options. The use of cereal grain cover crops...

  7. The role of snow cover and soil freeze/thaw cycles affecting boreal-arctic soil carbon dynamics

    NASA Astrophysics Data System (ADS)

    Yi, Y.; Kimball, J. S.; Rawlins, M. A.; Moghaddam, M.; Euskirchen, E. S.

    2015-07-01

    Northern Hemisphere permafrost affected land areas contain about twice as much carbon as the global atmosphere. This vast carbon pool is vulnerable to accelerated losses through mobilization and decomposition under projected global warming. Satellite data records spanning the past 3 decades indicate widespread reductions (∼ 0.8-1.3 days decade-1) in the mean annual snow cover extent and frozen season duration across the pan-Arctic domain, coincident with regional climate warming trends. How the soil carbon pool responds to these changes will have a large impact on regional and global climate. Here, we developed a coupled terrestrial carbon and hydrology model framework with detailed 1-D soil heat transfer representation to investigate the sensitivity of soil organic carbon stocks and soil decomposition to changes in snow cover and soil freeze/thaw processes in the Pan-Arctic region over the past three decades (1982-2010). Our results indicate widespread soil active layer deepening across the pan-Arctic, with a mean decadal trend of 6.6 ± 12.0 (SD) cm, corresponding with widespread warming and lengthening non-frozen season. Warming promotes vegetation growth and soil heterotrophic respiration, particularly within surface soil layers (≤ 0.2 m). The model simulations also show that seasonal snow cover has a large impact on soil temperatures, whereby increases in snow cover promote deeper (≥ 0.5 m) soil layer warming and soil respiration, while inhibiting soil decomposition from surface (≤ 0.2 m) soil layers, especially in colder climate zones (mean annual T ≤ -10 °C). Our results demonstrate the important control of snow cover in affecting northern soil freeze/thaw and soil carbon decomposition processes, and the necessity of considering both warming, and changing precipitation and snow cover regimes in characterizing permafrost soil carbon dynamics.

  8. General assessment of the influence of a municipal landfill site and environmental factors on the occurrence of keratinolytic fungi in soil.

    PubMed

    Ulfig, K; Płaza, G; Sztyler, A; Bronder, J; Terakowski, M; Guarro, J

    2000-01-01

    The study was to generally determine the influence of a municipal landfill site and environmental factors on the distribution of keratinolytic fungi in soil. The landfill site in Sosnowiec was selected for examination. Keratinolytic fungi occurred abundantly in soils of the landfill site examined and its surrounding area. Of 495 soil samples (Petri dishes) examined, 379 (76.56%) were found to be positive for keratinolytic fungi. Altogether, 1131 strains from 26 species were isolated from the samples. Among the fungi, some species with pathogenic properties (Microsporum racemosum, M. cookei, M. gypseum, Aphanoascus fulvescens and Scopulariopsis brevicaulis) were recorded. The influence of environmental factors on the qualitative and quantitative composition of keratinolytic fungi in the soils was complex. Among these factors, exchangeable acidity (pH in 1 M KCl, in particular), faecal bacterial contamination and the level of water deficit in soil were the most important. The conclusion has been drawn that municipal landfill sites are the sources of potentially pathogenic fungi with keratinolytic properties. PMID:10959197

  9. Agricultural land cover mapping with the aid of digital soil survey data

    NASA Technical Reports Server (NTRS)

    Stoner, E. R.

    1982-01-01

    A study is recounted which assessed the effect of stratifying multidate Landsat MSS data on land cover classification accuracy. The study area covered 49,184 ha (121,534 acres) in Gentry County in northwestern Missouri. A pixel-by-pixel comparison of the two land cover classifications with field-verified land cover indicated improvements in identification of all cover types when land areas were stratified by soils. The introduction of soil map information to the land cover mapping process can improve discrimination of land cover types and reduce confusion among crop types that may be caused by soil-specific management practices, soil-induced crop development differences, and background reflectance characteristics.

  10. Soil quality assessment for peat-mineral mix cover soil used in oil sands reclamation.

    PubMed

    Ojekanmi, A A; Chang, S X

    2014-09-01

    A soil quality (SQ) assessment and rating framework that is quantitative, iterative, and adaptable, with justifiable weighting for quality scores, is required for evaluating site-specific SQ at land reclamation sites. Such a framework needs to identify the minimum dataset that reflects the current knowledge regarding relationships between SQ indicators and relevant measures of ecosystem performance. Our objective was to develop nonlinear scoring functions for assessing the impact on SQ of peat-mineral mix (PMM) used as a cover soil at land reclamation sites. Soil functional indicators affected by PMM were extracted from existing databases and correlated with soil organic carbon (SOC). Based on defined objectives for SQ assessment, indicators with significant correlation ( < 0.05) to SOC were selected, normalized, and fitted to sigmoid functions using nonlinear regression procedure to establish SQ functions (SQFs) that can analyze changes in field capacity, permanent wilting point, soil nitrogen, and cation exchange capacity of PMM using SOC as input parameter. Application of the SQFs to an independent dataset produced ratings with mean differences similar to the treatment effects of mixing three levels of peat and mineral soil. These results show that derived ratings and weighing factors using SOC reflect the relationship between PMM treatment and other SQ indicators. Applying the developed SQFs to a long-term soil monitoring dataset shows that an increase or decrease in SOC from 10 to 20 g kg causes a significant change in SQ. This identifies the need for further nutrient and moisture management of PMM to support long-term SQ development in land reclamation. PMID:25603242