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1

Methane Oxidation in Landfill Cover Soil  

Microsoft Academic Search

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

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

2005-01-01

2

Methane oxidation in simulated landfill cover soil environments  

Microsoft Academic Search

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

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

1999-01-01

3

Temporal variability of soil gas composition in landfill covers  

Microsoft Academic Search

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

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

2011-01-01

4

Nitrous oxide emissions from landfill cover soils in Sweden  

Microsoft Academic Search

Emissions of nitrous oxide measured at 4 landfill sites were found to be higher where sewage sludge was used as a landfill cover, ranging from 0.011 to 35.7mg N2O-N m2h1. From landfill sites covered with mineral soils, N2O-emissions ranged from -0.0017 to 1.07mg N2O-N m2h1. However, extrapolation to the national level showed that sewage sludge could only be a minor

G. Börjesson; Bo H. Svensson

1997-01-01

5

Hydrologic modeling of soil water storage in landfill cover systems  

SciTech Connect

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.

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

1987-01-01

6

Methane oxidation and microbial exopolymer production in landfill cover soil  

Microsoft Academic Search

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

Helene A Hilger; David F Cranford; Morton A Barlaz

2000-01-01

7

Biodegradation of trace gases in simulated landfill soil cover systems.  

PubMed

The attenuation of methane and seven volatile organic compounds (VOCs) was investigated in a dynamic methane and oxygen counter gradient system simulating a landfill soil cover. The VOCs investigated were: Tetrachloromethane (TeCM), trichloromethane (TCM), dichloromethane (DCM), trichloroethylene (TCE), vinyl chloride (VC), benzene, and toluene. Soil was sampled at Skellingsted landfill, Denmark. The soil columns showed a high capacity for methane oxidation, with oxidation rates up to 184 g/m2/d corresponding to a 77% reduction of inlet methane. Maximal methane oxidation occurred at 15-20 cm depth, in the upper part of the column where there were overlapping gradients of methane and oxygen. All the chlorinated hydrocarbons were degraded in the active soil columns with removal efficiencies higher than 57%. Soil gas concentration profiles indicated that the removal of the fully chlorinated compound TeCM was because of anaerobic degradation, whereas the degradation of lower chlorinated compounds like VC and DCM was located in the upper oxic part of the column. Benzene and toluene were also removed in the active column. This study demonstrates the complexity of landfill soil cover systems and shows that both anaerobic and aerobic bacteria may play an important role in reducing the emission of trace components into the atmosphere. PMID:16111127

Scheutz, Charlotte; Kjeldsen, Peter

2005-07-01

8

Temporal variability of soil gas composition in landfill covers.  

PubMed

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

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

2010-11-12

9

Limits and dynamics of methane oxidation in landfill cover soils.  

PubMed

In order to understand the limits and dynamics of methane (CH(4)) oxidation in landfill cover soils, we investigated CH(4) oxidation in daily, intermediate, and final cover soils from two California landfills as a function of temperature, soil moisture and CO(2) concentration. The results indicate a significant difference between the observed soil CH(4) oxidation at field sampled conditions compared to optimum conditions achieved through pre-incubation (60 days) in the presence of CH(4) (50 ml l(-1)) and soil moisture optimization. This pre-incubation period normalized CH(4) oxidation rates to within the same order of magnitude (112-644 ?g CH(4) g(-1) day(-1)) for all the cover soils samples examined, as opposed to the four orders of magnitude variation in the soil CH(4) oxidation rates without this pre-incubation (0.9-277 ?g CH(4) g(-1) day(-1)). Using pre-incubated soils, a minimum soil moisture potential threshold for CH(4) oxidation activity was estimated at 1500 kPa, which is the soil wilting point. From the laboratory incubations, 50% of the oxidation capacity was inhibited at soil moisture potential drier than 700 kPa and optimum oxidation activity was typical observed at 50 kPa, which is just slightly drier than field capacity (33 kPa). At the extreme temperatures for CH(4) oxidation activity, this minimum moisture potential threshold decreased (300 kPa for temperatures <5°C and 50 kPa for temperatures >40°C), indicating the requirement for more easily available soil water. However, oxidation rates at these extreme temperatures were less than 10% of the rate observed at more optimum temperatures (? 30°C). For temperatures from 5 to 40°C, the rate of CH(4) oxidation was not limited by moisture potentials between 0 (saturated) and 50 kPa. The use of soil moisture potential normalizes soil variability (e.g. soil texture and organic matter content) with respect to the effect of soil moisture on methanotroph activity. The results of this study indicate that the wilting point is the lower moisture threshold for CH(4) oxidation activity and optimum moisture potential is close to field capacity. No inhibitory effects of elevated CO(2) soil gas concentrations were observed on CH(4) oxidation rates. However, significant differences were observed for diurnal temperature fluctuations compared to thermally equivalent daily isothermal incubations. PMID:20096554

Spokas, Kurt A; Bogner, Jean E

2010-01-21

10

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

Microsoft Academic Search

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

Alex De Visscher; Oswald Van Cleemput

2003-01-01

11

Impact assessment of intermediate soil cover on landfill stabilization by characterizing landfilled municipal solid waste.  

PubMed

Waste samples at different depths of a covered municipal solid waste (MSW) landfill in Beijing, China, were excavated and characterized to investigate the impact of intermediate soil cover on waste stabilization. A comparatively high amount of unstable organic matter with 83.3 g kg(-1) dry weight (dw) total organic carbon was detected in the 6-year-old MSW, where toxic inorganic elements containing As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn of 10.1, 0.98, 85.49, 259.7, 530.4, 30.5, 84.0, and 981.7 mg kg(-1) dw, respectively, largely accumulated because of the barrier effect of intermediate soil cover. This accumulation resulted in decreased microbial activities. The intermediate soil cover also caused significant reduction in moisture in MSW under the soil layer, which was as low as 25.9%, and led to inefficient biodegradation of 8- and 10-year-old MSW. Therefore, intermediate soil cover with low permeability seems to act as a barrier that divides a landfill into two landfill cells with different degradation processes by restraining water flow and hazardous matter. PMID:23764507

Qi, Guangxia; Yue, Dongbei; Liu, Jianguo; Li, Rui; Shi, Xiaochong; He, Liang; Guo, Jingting; Miao, Haomei; Nie, Yongfeng

2013-06-10

12

Attenuation of Methane and Volatile Organic Compounds in Landfill Soil Covers  

Microsoft Academic Search

trace components originate from hazardous materials deposited in the landfill or from biological or chemical The potential for natural attenuation of volatile organic compounds degradation of materials disposed of in the landfill. Due (VOCs) in landfill covers was investigated in soil microcosms incu- bated with methane and air, simulating the gas composition in landfill to pressure and concentration gradients, the

Charlotte Scheutz; Hans Mosbæk; Peter Kjeldsen

2004-01-01

13

Rapid Methane Oxidation in a Landfill Cover Soil †  

PubMed Central

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 ?M, 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.

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

1990-01-01

14

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

Microsoft Academic Search

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

Ruo He; Aidong Ruan; Chenjing Jiang; Dong-sheng Shen

2008-01-01

15

Microbial oxidation of CH 4 at different temperatures in landfill cover soils  

Microsoft Academic Search

Biological oxidation of CH4 is an important constraint on the emission of this gas from areas, such as landfills to the atmosphere. We studied the effect of temperature on methanotrophic bacteria in three different landfill cover soils, incubated in the laboratory. In samples of a young cover, consisting of wood chips and sewage sludge, the phospholipid fatty acids (PLFAs), regarded

Gunnar Börjesson; Ingvar Sundh; Bo Svensson

2004-01-01

16

Performance of soil and compost mixture in leachate purification at intermediate cover layer of tropical landfill  

Microsoft Academic Search

This research studied the performance of soil and compost as filter materials for preliminary purification of leachate at intermediate cover layer of tropical landfill. The experiments were conducted by using four columns filled with different types of filter materials, i.e. 1) soil (40% clay, 30% silt, 30% sand) 2) mixture of soil and planting soil 3) mixture of soil and

C. Chiemchaisri; T. Srisukphun; T. Srisuk

17

Short-term kinetic response of enhanced methane oxidation in landfill cover soils to environmental factors  

Microsoft Academic Search

This paper aims at a better understanding of methane oxidation under conditions that are representative of landfill cover\\u000a soils. The kinetics of methane oxidation were studied in landfill cover soils that had been exposed to high methane mixing\\u000a ratios. This was done in batch experiments, under various environmental conditions. V\\u000a max increased exponentially with temperature in the range 5–35??C, with

A. De Visscher; Michael Schippers; Oswald Van Cleemput

2001-01-01

18

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

Microsoft Academic Search

A compacted soil liner (CSL) has been widely used as a single barrier layer or a part of composite barrier layer in the landfill final cover system to prevent water infiltration into solid wastes for its acceptable hydraulic permeability. This study was conducted to test whether the CSL was also effective in prohibiting landfill gas emissions. For this purpose, three

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

2008-01-01

19

Relevance of soil physical properties for the microbial oxidation of methane in landfill covers  

Microsoft Academic Search

The microbial oxidation of methane in landfill cover soils offers great potential to reduce methane emissions from landfills. High methane degradation rates can only be accomplished if the supply of atmospheric oxygen to the methanotrophic community is adequate. Thus, if environmental variables such as pH or nutrient status are not limiting, system performance is suggested to be governed by the

Julia Gebert; Alexander Groengroeft; Eva-Maria Pfeiffer

2011-01-01

20

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

Microsoft Academic Search

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

Alex De Visscher; Ingrid De Pourcq; Jeffrey Chanton

2004-01-01

21

Analysis of flow behavior in a landfill with cover soil of low hydraulic conductivity  

Microsoft Academic Search

This paper presents the results of field tests of hydrologic parameters in a landfill and the results of numerical simulation\\u000a to find the efficiency of the pumping method to reduce leachate levels in the landfill. The field hydraulic conductivity and\\u000a storativity of waste and buried cover soils in the landfill are measured by pumping and slug tests. The hydrologic condition

Y.-S. Jang

2000-01-01

22

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

Microsoft Academic Search

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

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

2011-01-01

23

Methane oxidation in landfill cover soils, as revealed by potential oxidation measurements and phospholipid fatty acid analyses  

Microsoft Academic Search

Landfills account for ca. 10% of the annual global burden of atmospheric methane. Part of the efflux is mitigated by means of biological methane oxidation in the landfill covers. In this study, two types of landfill cover soils (mineral soil and sewage sludge) were compared with respect to methane emissions as well as potential methane oxidation capacity and the PLFA

Gunnar Börjesson; Ingvar Sundh; Anders Tunlid; Bo H. Svensson

1998-01-01

24

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

PubMed

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

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

2012-03-03

25

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

PubMed

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

De Visscher, Alex; Van Cleemput, Oswald

2003-01-01

26

Microbial mitigation of greenhouse gas emissions from landfill cover soils  

Microsoft Academic Search

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

Sung-Woo Lee

2008-01-01

27

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

PubMed

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 of sandy soil that was used as daily covers soils. Therefore, the effects of cover soils on the shear strength properties of MSW should be evaluated and taken into consideration during stability analyses and design. PMID:19167874

Hossain, Md Sahadat; Haque, Mohamed A

2009-01-23

28

Evapotranspiration Covers for Landfills  

Microsoft Academic Search

Safe disposal or containment of waste continues to be one of the world's largest environmental challenges. If not properly\\u000a handled, wastes from municipal, commercial, industrial, and mining sources can pollute surface and groundwater, and release\\u000a damaging gases. One potentially useful technology is the evapotranspiration (ET) cover for landfills and waste sites. Designed\\u000a to use engineered soil and vegetation layers, an

S. A. Rock

29

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

SciTech Connect

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

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

2011-05-15

30

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

PubMed

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

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

2010-11-09

31

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

PubMed

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 ?91,500?molm(-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 -380?molm(-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

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

2011-12-03

32

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

Microsoft Academic Search

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 CHâ oxidation rate (2.36 ng CHâ⁻¹g⁻¹ soil). When wetter, CHâ consumption was slower (e.g.,

Pascal Boeckx; Oswald Van Cleemput

1996-01-01

33

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

Microsoft Academic Search

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

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

2008-01-01

34

Minimizing N2O fluxes from full-scale municipal solid waste landfill with properly selected cover soil.  

PubMed

Municipal solid waste landfills emit nitrous oxide (N2O) gas. Assuming that the soil cover is the primary N2O source from landfills, this study tested, during a four-year project, the hypothesis that the proper use of chosen soils with fine texture minimizes N2O emissions. A full-scale sanitary landfill, a full-scale bioreactor landfill and a cell planted with Nerium indicum or Festuca arundinacea Schreb, at the Hangzhou Tianziling landfill in Hangzhou City were the test sites. The N2O emission rates from all test sites were considerably lower than those reported in the published reports. Specifically, the N2O emission rate was dependent on soil water content and nitrate concentrations in the cover soil. The effects of leachate recirculation and irrigation were minimal. Properly chosen cover soils applied to the landfills reduced N2O flux. PMID:18574960

Zhang, Houhu; He, Pinjing; Shao, Liming; Qu, Xian; Lee, Duujong

2008-01-01

35

Characterization of adsorption removal of hydrogen sulfide by waste biocover soil, an alternative landfill cover.  

PubMed

Landfill is an important anthropogenic source of odorous gases. In this work, the adsorption characteristics of H(2)S on waste biocover soil, an alternative landfill cover, were investigated. The results showed that the adsorption capacity of H(2)S increased with the reduction of particle size, the increase of pH value and water content of waste biocover soil. The optimal composition of waste biocover soil, in regard to operation cost and H(2)S removal performance, was original pH value, water content of 40% (w/w) and particle size of ?4 mm. A net increase was observed in the adsorption capacity of H(2)S with temperatures in the range of 4-35°C. The adsorption capacity of H(2)S on waste biocover soil with optimal composition reached the maximum value of 60±1 mg/kg at oxygen concentration of 10% (v/v). When H(2)S concentration was about 5% (v/v), the adsorption capacity was near saturation, maintaining at 383±40 mg/kg. Among the four experimental soils, the highest adsorption capacity of H(2)S was observed on waste biocover soil, followed by landfill cover soil, mulberry soil, and sand soil, which was only 9.8% of that of waste biocover soil. PMID:21146927

He, Ruo; Xia, Fang-Fang; Wang, Jing; Pan, Chang-Liang; Fang, Cheng-Ran

2010-11-23

36

Spatial and temporal diversity of methanotrophs in a landfill cover soil are differentially related to soil abiotic factors.  

PubMed

Methanotrophs present in landfill cover soil can limit methane emissions from landfill sites by oxidizing methane produced in landfill. Understanding the spatial and temporal distribution of populations of methanotrophs and the factors influencing their activity and diversity in landfill cover soil is critical to devise better landfill cover soil management strategies. pmoA-based microarray analyses of methanotroph community structure revealed a temporal shift in methanotroph populations across different seasons. Type II methanotrophs (particularly Methylocystis sp.) were found to be present across all seasons. Minor shifts in type I methanotroph populations were observed. In the case of spatial distribution, only minor differences in methanotroph community structure were observed with no recognizable patterns (both vertical and horizontal) at a 5?m scale. Correlation analysis between soil abiotic parameters (total C, N, NH4 (+) , NO3 (-) and water content) and distribution of methanotrophs revealed a lack of conclusive evidence for any distinct correlation pattern between measured abiotic parameters and methanotroph community structure, suggesting that complex interactions of several physico-chemical parameters shape methanotroph diversity and activity in landfill cover soils. PMID:23765893

Kumaresan, Deepak; Abell, Guy C J; Bodrossy, Levente; Stralis-Pavese, Nancy; Murrell, J Colin

2009-08-13

37

Landfill Gas Effects on Evapotranspirative Landfill Covers  

Microsoft Academic Search

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

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

2005-01-01

38

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

PubMed

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

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

2010-10-12

39

Methanotrophic production of extracellular polysaccharide in landfill cover soils  

Microsoft Academic Search

A bench-scale soil reactor was used to study methane oxidation and EPS production under tropical conditions. The study of pertinent environmental factors affecting EPS production was carried out by batch cultivation of methanotrophs. These factors included variations in temperature (20°C to 45°C), soil water content (5% to 33%), and the supply ratios of methane\\/oxygen. The bench-scale study revealed that excessive

W. Chiemchaisri; J. S. Wu; C. Visvanathan

40

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

SciTech Connect

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

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

2009-09-15

41

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

PubMed

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

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

2009-06-13

42

Evaluation of alternative landfill cover soils for attenuating hydrogen sulfide from construction and demolition (C&D) debris landfills  

Microsoft Academic Search

Hydrogen sulfide (H2S) generated from C&D debris landfills has emerged as a major environmental concern due to odor problems and possible health impacts to landfill employees and surrounding residents. Research was performed to evaluate the performance of various cover materials as control measures for H2S emissions from C&D debris landfills. Twelve laboratory-scale simulated landfill columns containing gypsum drywall were operated

Cristine Plaza; Qiyong Xu; Timothy Townsend; Gabriel Bitton; Matthew Booth

2007-01-01

43

Gas Movement Through Fractured Landfill Cover Materials.  

National Technical Information Service (NTIS)

Bidirectional gas movement through fractured landfill cover materials is being studied at the Mallard North Landfill in DuPage County, Illinois. Vertical pressure and concentration gradients were monitored during changing meteorological and soil moisture ...

J. E. Bogner C. A. Moore

1986-01-01

44

N 2O emissions from municipal solid waste landfills with selected infertile cover soils and leachate subsurface irrigation  

Microsoft Academic Search

This study presents the field investigations into the effects of cover soils and leachate subsurface irrigation on N2O emissions from municipal solid waste landfills. Landfill Site A and Site B, covered with carefully chosen infertile soils, were selected to monitor their diurnal and seasonal variations of N2O emissions. The annual average N2O flux was 469±796?gN2O-Nm?2h?1 in Site B with leachate

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

2008-01-01

45

Microbial oxidation of CH(4) at different temperatures in landfill cover soils.  

PubMed

Biological oxidation of CH(4) is an important constraint on the emission of this gas from areas, such as landfills to the atmosphere. We studied the effect of temperature on methanotrophic bacteria in three different landfill cover soils, incubated in the laboratory. In samples of a young cover, consisting of wood chips and sewage sludge, the phospholipid fatty acids (PLFAs), regarded as biomarkers for type I methanotrophs (16:1omega5t, 16:1omega6c, 16:1omega8c), primarily increased at low temperatures (5-10 degrees C). On the other hand, the PLFA marker for type II methanotrophs (18:1omega8c) was highly elevated only at 20 degrees C. These results suggest that temperature can determine the selection of methanotroph populations. PMID:19712300

Börjesson, Gunnar; Sundh, Ingvar; Svensson, Bo

2004-06-01

46

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

SciTech Connect

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 net sink for atmospheric CH{sub 4} (uptake up to -380 {mu}mol m{sup -2} d{sup -1}) during the experimental period. Methane concentration profiles also indicated strong variability in CH{sub 4} loading over short distances in the cover soil, while potential methanotrophic activity derived from GPPTs was high (v{sub max} {approx} 13 mmol L{sup -1}(soil air) h{sup -1}) at a location with substantial CH{sub 4} loading. Our results provide a basis to assess spatial and temporal variability of CH{sub 4} dynamics in the complex terrain of a landfill-cover soil.

Schroth, M.H., E-mail: martin.schroth@env.ethz.ch [Institute of Biogeochemistry and Pollutant Dynamics, ETH Zuerich, Universitaetstrasse 16, 8092 Zuerich (Switzerland); Eugster, W. [Institute of Agricultural Sciences, ETH Zuerich, Universitaetstrasse 2, 8092 Zuerich (Switzerland); Gomez, K.E. [Institute of Biogeochemistry and Pollutant Dynamics, ETH Zuerich, Universitaetstrasse 16, 8092 Zuerich (Switzerland); Gonzalez-Gil, G. [Laboratory for Environmental Biotechnology, EPF Lausanne, 1015 Lausanne (Switzerland); Niklaus, P.A. [Institute of Agricultural Sciences, ETH Zuerich, Universitaetstrasse 2, 8092 Zuerich (Switzerland); Oester, P. [Oester Messtechnik, Bahnhofstrasse 3, 3600 Thun (Switzerland)

2012-05-15

47

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

Microsoft Academic Search

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

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

2008-01-01

48

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

NASA Astrophysics Data System (ADS)

When the open system isotope method has been used to determine the methane oxidation efficiency of a landfill cover soil, it has been assumed that gas transport from the landfill is primarily driven by advection, a mechanism that is not associated with isotopic fractionation. A controlled laboratory experiment revealed that this approach underestimated the methane oxidation efficiency because it underestimated the importance of molecular diffusion during gas transport. In a worst-case scenario laboratory column experiment where diffusion was an important gas transport mode, a comparison between a mass balance and the open system isotope method revealed that the latter underestimated methane oxidation by a factor 2 to 4. The vertical profile of the ?13C value of methane in the column confirmed that isotope fractionation associated with gas transport occurred. Similar profiles were observed in the field, but the effect was less pronounced. It is concluded that the isotope method as currently applied produces a conservative estimate of methane oxidation by landfill cover soils.

de Visscher, Alex; de Pourcq, Ingrid; Chanton, Jeffrey

2004-09-01

49

[Effects of methane stress on oxidation rates and microbial community structures in different landfill cover soils].  

PubMed

As compared with the ordinary landfill cover material, clay soil, the effect of methane stress on oxidation rate and microbial community structure was investigated in waste soil (material from biologically treated municipal solid waste). The results showed that the moisture content of the clay soil was low, due to the low water retaining capacity. As environmental temperature and rainfall changed, the clay soil caked and inhibited methanotrophs growth. However, with a high organic matter, water-holding capacity and porosity, the waste soil provided a favor condition for methanotrophs growth and propagation. After exposure to methane flow for 120 days, methane oxidation potential in the middle and bottom layers of the waste soil column increased to 11.25-13.48 micromol/(g x h), which was 10.4-24.5 times higher than that in clay soil column. The topsoils were both found to be dried and inhibit methane oxidation. Methane oxidation (removal) efficiency by the waste soil column reached 48.3% at the end of the experiment, which was 5-6 times higher than that by the clay soil column. The amounts of the phospholipid fatty acid (PLFA) biomarks 16:1 omega 8c and 18:1 omega 8c for Type I and II methanotrophs, respectively, showed that a strong linear relationship was observed between methane oxidation potential and PLFA 18:1 omega 8c content in soil samples. PMID:19256403

He, Ruo; Jiang, Chen-jing; Wang, Jing; Gao, Qing-jun; Shen, Dong-sheng

2008-12-01

50

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 ...

51

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

SciTech Connect

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.

Mahieu, Koenraad [Laboratory of Applied Physical Chemistry (ISOFYS), Ghent University, Coupure links 653, B-9000 Ghent (Belgium); Department of Applied Mathematics, Biometrics and Process Control (BIOMATH), Ghent University, Coupure links 653, B-9000 Ghent (Belgium)], E-mail: Koenraad.mahieu@lid.kviv.be; De Visscher, Alex [Department of Chemical and Petroleum Engineering, Schulich School of Engineering, University of Calgary, 2500 University Drive N.W., Calgary, Alberta, T2N 1N4 (Canada); Vanrolleghem, Peter A. [Department of Applied Mathematics, Biometrics and Process Control (BIOMATH), Ghent University, Coupure links 653, B-9000 Ghent (Belgium); Department of Civil Engineering (modelEAU), Universite Laval, Pavillon Pouliot, Quebec, G1K 7P4 (Canada); Van Cleemput, Oswald [Laboratory of Applied Physical Chemistry (ISOFYS), Ghent University, Coupure links 653, B-9000 Ghent (Belgium)

2008-07-01

52

PERFORMANCE MONITORING OF SOIL COVER FIELD TRIALS AT THE REGINA MUNICIPAL LANDFILL  

Microsoft Academic Search

The City of Regina Fleet Street Landfill, located north-east of Regina, Saskatchewan, is approaching its maximum capacity after a 48-year operating life. As part of closure planning, four large-scale test plots encompassing two alternate cover system designs (an evapotranspiration cover and a capillary break type cover) were constructed on north and south-facing slopes of the landfill in the summer of

Randi L. Strunk; Bonnie S. Dobchuk; Gary Nieminen; S. Lee Barbour; Mike A. O'Kane

53

Effect of earthworms on the community structure of active methanotrophic bacteria in a landfill cover soil  

Microsoft Academic Search

In the United Kingdom, landfills are the primary anthropogenic source of methane emissions. Methanotrophic bacteria present in landfill biocovers can significantly reduce methane emissions via their capacity to oxidize up to 100% of the methane produced. Several biotic and abiotic parameters regulate methane oxidation in soil, such as oxygen, moisture, methane concentration and temperature. Earthworm-mediated bioturbation has been linked to

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

2008-01-01

54

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

NASA Astrophysics Data System (ADS)

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.

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

2007-12-01

55

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

PubMed

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

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

2009-02-25

56

[Effect of operational modes on community structure of type I methanotroph in the cover soil of municipal solid waste landfill].  

PubMed

Type I methanotroph is crucial for methane oxidization and it responses fast to the changes in environment. In this study, 16S rDNA-based denaturing gradient gel electrophoresis (DGGE) gene fingerprint technology was applied to investigate the effect of operational modes, i. e. high-density polyethylene liner (HDPE) isolation or subsurface irrigation of landfill leachate and vegetation, on community structure and diversity of type I methanotroph in soils covering municipal solid waste landfill. 16S rDNA based phylogenetic analysis reveals type I methanotroph in all tested soils belongs to Methylobacter. According to Shannon-Wiener diversity index and principal component analysis, landfill leachate subsurface irrigation and vegetation have more impact on type I methanotroph community structure and diversity than HDPE liner isolation does, and they reduce type I methanotroph diversity. Leachate irrigation is supposed to inhibit the growth of Methylobacter population. Community structure of type I methanotroph in landfill cover soil isolated by HDPE, i.e. invaded by landfill gas, shifts during long-term gas interference. When cover age is 1.5 years old, Shannon-Wiener diversity index of type I methanotroph reaches its maximum. PMID:19143406

Yu, Ting; He, Pin-Jing; Lü, Fan; Shao, Li-Ming

2008-10-01

57

Microbial oxidation of CH 4 at high partial pressures in an organic landfill cover soil under different moisture regimes  

Microsoft Academic Search

The uptake and utilization of CH4 at high concentrations (5–18% vol.) and different soil moistures were followed for samples from a landfill cover soil with a high organic matter content. Measurements of the utilization of CH4 and O2, and production of CO2 indicated that the activity of methanotrophic organisms accounted for most of the O2 respiration. At water saturation, CH4

Gunnar Börjesson; Ingvar Sundh; Anders Tunlid; Åsa Frostegård; Bo H Svensson

1998-01-01

58

Capacity for biodegradation of CFCs and HCFCs in a methane oxidative counter-gradient laboratory system simulating landfill soil covers.  

PubMed

The attenuation of methane and four chlorofluorocarbons was investigated in a dynamic methane and oxygen counter-gradient system simulating a landfill soil cover. Soil was sampled at Skellingsted Landfill, Denmark. The soil columns showed a high capacity of methane oxidation with oxidation rates of 210 g m(-2) d(-1) corresponding to a removal efficiency of 81%. CFC-11 and to a lesser extent also CFC-12 were degraded in the active soil columns. The average removal efficiency was 90% and 30% for CFC-11 and CFC-12, respectively. Soil gas concentration profiles indicated that the removal was due to anaerobic degradation, which was verified in anaerobic batch experiments where CFC-11 was rapidly degraded. HCFC-21 and HCFC-22 were also degraded in active soil columns (61% and 41%, respectively), but compared to the CFCs, the degradation was located in the upper oxic part of the column with overlapping gradients of methane and oxygen. High oxidation rates of methane and HCFCs were obtained in soil microcosms incubated with methane. When increasing the column inlet flow, the oxidation zone was moved upward in the column, and the removal efficiency of methane and HCFCs decreased. The removal of CFCs was, however, less affected since the anaerobic zone expanded with increasing inlet flow rates. This study demonstrates the complexity of landfill soil cover systems and shows that both anaerobic and aerobic bacteria may play a very important role in reducing the emission of not only methane but also trace components into the atmosphere. PMID:14655700

Scheutz, Charlotte; Kjeldsen, Peter

2003-11-15

59

Evaluation of soil top-cover systems to minimize infiltration into a sanitary landfill: A case study  

NASA Astrophysics Data System (ADS)

The design of a top-cover system is a very important aspect of the closure of sanitary landfills. Soil material properties, sequencing, and vegetation are critical to top-cover design. To date, very few field investigations have been undertaken to determine the effectiveness of these designs. Results from a field investigation of top-covers proposed for an active landfill site in south Florida are reported here. Measurements were made of each component of the water balance equation: ? S = [ P + I] - [ ET + R + Q] where S, P, I, ET, R, and Q represent water storage, rainfall, irrigation, evapotranspiration, surface runoff, and deep seepage, respectively. Deep seepage, determined using soil water tensiometers, is the amount of water infiltrating the landfill top-cover and is therefore the upper limit of potential leachate generation. Results indicate that the locally available rock tailings (carbonate silt) is an effective topliner component of the top-cover system. The results of the field investigation also showed that the EPA water balance model used to estimate infiltration during landfill design was greater than the actual field measurements.

Weeks, Olaf L.; Mansell, Robert S.; McCallister, Scott W.

1992-09-01

60

N2O emissions from municipal solid waste landfills with selected infertile cover soils and leachate subsurface irrigation.  

PubMed

This study presents the field investigations into the effects of cover soils and leachate subsurface irrigation on N2O emissions from municipal solid waste landfills. Landfill Site A and Site B, covered with carefully chosen infertile soils, were selected to monitor their diurnal and seasonal variations of N2O emissions. The annual average N2O flux was 469 +/- 796 microg N2O-N m(-2) h(-1) in Site B with leachate subsurface irrigation, three times that of Site A without leachate irrigation. When an additional soil containing lower contents of carbon and nitrogen was introduced to cover part of Site B, its N2O fluxes decreased by 1-2 orders of magnitude compared with the left area of Site B. This suggested that carefully selected cover soils could substantially reduce N2O emissions even under leachate subsurface irrigation. Statistical analysis proved that the availabilities of soil moisture and mineralized nitrogen were the key parameters controlling landfill N2O emissions. PMID:18524440

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

2008-06-03

61

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

PubMed

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

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

2010-10-23

62

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

Microsoft Academic Search

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

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

2008-01-01

63

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

PubMed

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

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

64

Methane Oxidation in Landfill Cover Soils, is a 10% Default Value Reasonable?  

Microsoft Academic Search

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 landfi ll covers. Both column measurements and in situ fi eld measurements were included. Th e means for the fraction of methane oxidized on transit across the soil covers ranged from 22 to

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

2009-01-01

65

Transport and Reaction Processes Affecting the Attenuation of Landfill Gas in Cover Soils  

Microsoft Academic Search

Methane and trace organic gases produced in landfi ll waste are partly oxidized in the top 40 cm of landfi ll cover soils under aerobic conditions. Th e balance between the oxidation of landfi ll gases and the ingress of atmospheric oxygen into the soil cover determines the attenuation of emissions of methane, chlorofl uorocarbons, and hydrochlorofl uorocarbons to the

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

2008-01-01

66

Phylogenetic analysis of methanotrophic communities in cover soils of a landfill in Ontario.  

PubMed

We examined the methanotrophs in the Trail Road Landfill soils, Ottawa, Ontario, through cultivation-independent molecular assay and the culturing approach. Denaturing gradient gel electrophoresis (DGGE) analysis of amplified methanotroph-specific 16S rDNA gene fragments revealed a more diverse type I (RuMP pathway) methanotrophic community than type II (serine pathway) in 17 soil samples taken along a 50 m transect. The type II methanotrophic community was less diverse, with the dominance of Methylocystis in almost all samples, and clustering with high similarity (85%-88%). Also, the results showed that the C/N ratio of soil organic matter could significantly affect the methanotrophic community structures. The DGGE results were supported by sequence analysis of cloned pmoA. Members of the genera Methylobacter (type I), Methylocaldum (type X), and Methylocystis (type II) appeared to be the dominant methanotrophs. From methanotrophic enrichments, we isolated type I Methylobacter sp., and 3 type II Methylocystis spp.,which appeared to be one of the dominant bacteria species in the soil sample from which isolates were obtained. PMID:19898553

Lin, Bin; Monreal, Carlos M; Tambong, James T; Miguez, Carlos B; Carrasco-Medina, Lorna

2009-09-01

67

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

SciTech Connect

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.

Boeckx, P.; Van Cleemput, O. [Univ. of Ghent (Belgium)

1996-01-01

68

Construction Costs of Six Landfill Cover Designs  

SciTech Connect

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.

Dwyer, S.F.

1998-12-23

69

Cost comparisons of alternative landfill final covers  

SciTech Connect

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.

Dwyer, S.F.

1997-02-01

70

Field-scale labelling and activity quantification of methane-oxidizing bacteria in a landfill-cover soil.  

PubMed

Aerobic methane-oxidizing bacteria (MOB) play an important role in soils, mitigating emissions of the greenhouse gas methane (CH(4)) to the atmosphere. Here, we combined stable isotope probing on MOB-specific phospholipid fatty acids (PLFA-SIP) with field-based gas push-pull tests (GPPTs). This novel approach (SIP-GPPT) was tested in a landfill-cover soil at four locations with different MOB activity. Potential oxidation rates derived from regular- and SIP-GPPTs agreed well and ranged from 0.2 to 52.8 mmol CH(4) (L soil air)(-1) day(-1). PLFA profiles of soil extracts mainly contained C(14) to C(18) fatty acids (FAs), with a dominance of C(16) FAs. Uptake of (13) C into MOB biomass during SIP-GPPTs was clearly indicated by increased ?(13)C values (up to c. 1500‰) of MOB-characteristic FAs. In addition, (13)C incorporation increased with CH(4) oxidation rates. In general, FAs C(14:0) , C(16:1?8), C(16:1?7) and C(16:1?6) (type I MOB) showed highest (13)C incorporation, while substantial (13)C incorporation into FAs C(18:1?8) and C(18:1?7) (type II MOB) was only observed at high-activity locations. Our findings demonstrate the applicability of the SIP-GPPT approach for in situ quantification of potential CH(4) oxidation rates and simultaneous labelling of active MOB, suggesting a dominance of type I MOB over type II MOB in the CH(4)-oxidizing community in this landfill-cover soil. PMID:22928887

Henneberger, Ruth; Chiri, Eleonora; Blees, Jan; Niemann, Helge; Lehmann, Moritz F; Schroth, Martin H

2012-09-19

71

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

PubMed

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

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

2011-08-02

72

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

SciTech Connect

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

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

1986-09-01

73

Stable isotope pulse-chasing and compound specific stable carbon isotope analysis of phospholipid fatty acids to assess methane oxidizing bacterial populations in landfill cover soils.  

PubMed

The oxidation of methane by bacteria residing in soils constitutes an important terrestrial methane sink. These bacteria are particularly abundant in the covering soils of landfill caps due to the supply of high concentrations of methane from the landfill below. Only about 0.1% of soil bacteria are amenable to available methods of culturing, resulting in the need for a method of in situ analysis. A combination of phospholipid fatty acid (PLFA) analysis and stable isotopic labeling has been employed in this investigation as a means of cultivation-independent bacterial analysis. Soil samples taken from the profiles of two landfill caps, one of clay and one of sand, were incubated with 13C-labeled methane. PLFAs were analyzed by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) in order to determine their 13C content, from which the PLFA distribution of the methane-oxidizing bacteria was calculated. Neither landfill cap supported communities of bacteria capable of oxidizing ambient levels of methane but only those elevated levels that are usually attributable to landfills. The clay-capped landfill profile exhibited a change in the methane-oxidizing bacterial community with depth, whereas the sand-capped landfill site displayed a mixture of both type I and II methanotrophs throughout the profile. Two additional samples, taken from sites where methane production was evident, were particularly dominated by type II methanotrophic bacteria. PMID:15046336

Crossman, Zoë M; Abraham, Faye; Evershed, Richard P

2004-03-01

74

Field water balance of landfill final covers.  

PubMed

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

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

75

Field Water Balance of Landfill Final Covers  

SciTech Connect

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 asses 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), instrumented drainage lysimeters over a range of climates at 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%, 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 barriers. Average percolation rates for alternative covers ranged between 33 and 160 mm/yr (6 and 18% if 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.

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

2004-11-15

76

Reduction of Methane Emission From Landfill Through Microbial Activities in Cover Soil: A Brief Review  

Microsoft Academic Search

Scientifically designed landfill or open dumpsites are used for disposal of municipal solid waste (MSW) in many developed and developing countries. These two systems pose two environmental challenges such as generation of landfill leachate and emission of greenhouse gases (GHGs). Because the GHG emission has been considered to be a global threat, various options have been tried to mitigate the

CHART CHIEMCHAISRI; WILAI CHIEMCHAISRI; SUNIL KUMAR; PRANEETH NISHADI WICRAMARACHCHI

2012-01-01

77

Reduction of Methane Emission from Landfill through Microbial Activities in Cover Soil: A Brief Review  

Microsoft Academic Search

Scientifically designed landfill and\\/or open dumpsites are used for disposal of municipal solid waste (MSW) in many developed and developing countries. These two systems pose two environmental challenges viz., generation of landfill leachate and emission of greenhouse gases (GHGs). Since the GHG emission has been considered to be a global threat, various options have been tried to mitigate the emission

Chart Chiemchaisri; Wilai Chiemchaisri; Sunil Kumar; Praneeth Nishadi Wicramarachchi

2011-01-01

78

Current knowledge of microbial community structures in landfills and its cover soils  

Microsoft Academic Search

Landfills are a vital component of our waste handling processes. Our lack of knowledge on the microbial processes in these\\u000a systems, however, hampers our ability to design the next generation of landfills that: (1) enhance the rate and extent of\\u000a waste decomposition, (2) produce byproducts of some value (e.g., methane that can be used for energy generation), and, (3)\\u000a minimize

Jeremy D. Semrau

2011-01-01

79

On the performance of capillary barriers as landfill cover  

Microsoft Academic Search

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

M. Kämpf; H. Montenegro

1997-01-01

80

Decision Analysis for Design of Evapotranspirative Landfill Covers  

Microsoft Academic Search

A decision framework was developed to identify the o ptimal cover thickness, soil type, and soil density for an evapotranspirative landfill cover. A simplified model was used to consider the hydraulic performance of several cover alternatives during a design precipitation event , neglecting effect s of interflow, surface water runoff, and moisture rem oval due to evapotranspiration . Monte Carlo

John S. McCartney; Jorge G. Zornberg

81

Mitigating CH? emissions in semi-aerobic landfills: impacts of operating conditions on abundance and community structure of methanotrophs in cover soils.  

PubMed

Methanotrophs are the most important sink of CH?, which is a more highly potent greenhouse gas than CO?. Methanotrophic abundance and community diversity in cover soils from two typical semi-aerobic landfills (SALs) in China were detected using real-time polymerase chain reaction (real-time-PCR) and denaturing gradient gel electrophoresis (DGGE) based on 16S rRNA genes, respectively. Real time-PCR showed that Type I methanotrophs ranged from 1.07 × 10? to 2.34 × 10? copies/g soil and that of Type II methanotrophs from 1.51 × 10? to 1.83 × 10? copies/g soil. The ratio of Type II to Type I methanotrophic copy numbers ranged from 5.61 to 21.89, indicating that Type II methanotrophs dominated in SAL. DGGE revealed that Type I methanotrophs responded more sensitively to the environment, changing as the community structure varied with different soil types and locations. Methylobacter, Methylosarcina, and Methylomicrobium for Type I, and Methylocystis for Type II were most prevalent in the SAL cover layer. Abundant interflow O? with high CH? concentration in SALs is the reason for the higher population density of methanotrophs and the higher enrichment of Type II methanotrophs compared with anaerobic landfills and other ecosystems, which proved a conclusion that increasing the oxygen supply in a landfill cover layer would greatly improve CH? mitigation. PMID:23711522

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

2013-07-28

82

Effect of substrate interaction on oxidation of methane and benzene in enriched microbial consortia from landfill cover soil.  

PubMed

The interaction of methane and benzene during oxidation in enriched methane-oxidizing consortium (MOC) and in benzene-oxidizing consortium (BOC) from landfill cover soil was characterized. Oxidation of both methane and benzene occurred in the MOC due to the coexistence of bacteria responsible for benzene oxidation, as well as methanotrophs, whereas in the BOC, only benzene was oxidized, not methane. Methane oxidation rates in the MOC were decreased with increasing benzene/methane ratio (mol/mol), indicating its methane oxidation was inhibited by the benzene coexistence. Benzene oxidation rates in the MOC, however, were increased with increasing benzene/methane ratio. The benzene oxidation in the BOC was not affected by the coexistence of methane or by the ratio of methane/benzene ratio (mol/mol). No effect of methane or benzene was found on the dynamics of functional genes, such as particulate methane monooxygenase and toluene monooxygenase, in association with oxidation of methane and benzene in the MOC and BOC. PMID:21847790

Lee, Eun-Hee; Park, Hyunjung; Cho, Kyung-Suk

2011-01-01

83

Instrumentation for Continuous Monitoring of Meteorological Variables and Soil Gas Pressure in Landfill Cover.  

National Technical Information Service (NTIS)

To examine changes in soil gas pressure relative to changes in atmospheric pressure and other meteorological variables, weather station sensors and electronic pressure transducers were interfaced with an RCA COSMAC microcomputer. The microcomputer control...

C. Moore M. Vogt J. Bogner

1986-01-01

84

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

Microsoft Academic Search

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

C. Moore; M. Vogt; J. Bogner

1986-01-01

85

Evaluation of potential inhibitors of methanogenesis and methane oxidation in a landfill cover soil  

Microsoft Academic Search

Biological methane (CH4) production is an anaerobic process, while CH4 consumption occurs predominantly under aerobic conditions; however, both processes can occur simultaneously in soil. Thus, field measurements of CH4 flux reflect the net result of both consumption and production reactions. Specific inhibitors of either CH4 consumption or production processes offer the opportunity for assessing the rates of these two processes

A. S. K. Chan; T. B. Parkin

2000-01-01

86

Seasonal variation in methane oxidation in a landfill cover soil as determined by an in situ stable isotope technique  

Microsoft Academic Search

Seasonal variations in the oxidation of methane during its transport across the soil cap of a landfill in Leon County, Florida, were determined in situ with a stable isotopic technique. The approach contrasted the delta13C values of emitted and anoxic zone CH4 and utilized measurements of the isotopic fractionation factor alpha, which varied inversely with temperature from 1.025 to 1.049.

Jeffrey Chanton; Karen Liptay

2000-01-01

87

WATER BALANCE PERFORMANCE OF FINAL LANDFILL COVERS IN AN ARID ENVIRONMENT  

Microsoft Academic Search

A large-scale field demonstration comparing final landfill cover designs was constructed and is currently being monitored at Sandia National Laboratories in Albuquerque, New Mexico. Two conventional cover designs (a RCRA Subtitle 'D' Soil Cover and a RCRA Subtitle 'C' Compacted Clay Cover) were constructed side-by- side with four alternative landfill test covers (Geosynthetic Clay Liner {GCL} Cover, Capillary Barrier, Anisotropic

Stephen F. Dwyer; Bruce Reavis

88

16S rRNA based T-RFLP analysis of methane oxidising bacteria—Assessment, critical evaluation of methodology performance and application for landfill site cover soils  

Microsoft Academic Search

Methanotrophic bacteria have a ubiquitous distribution in the environment and play an important role in global climate warming by lowering methane emission into the atmosphere. Globally, landfill sites produce about 10% of the methane entering the atmosphere, and soils above landfill sites have been shown to contain methanotrophic populations with the highest methane oxidation capacity measured.Landfill site simulating lysimeters were

Nancy Stralis-Pavese; Levente Bodrossy; Thomas G. Reichenauer; Alexandra Weilharter; Angela Sessitsch

2006-01-01

89

MODELS FOR HYDROLOGIC DESIGN OF EVAPOTRANSPIRATION LANDFILL COVERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

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...

90

Transformation of a Landfill Covering Amended with Municipal Waste Compost, Perugia, Italy  

Microsoft Academic Search

This research deals with the transformation of an anthropomor- phous 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

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

2007-01-01

91

Methane oxidation in a landfill cover with capillary barrier  

Microsoft Academic Search

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

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

2005-01-01

92

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 ...

93

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

Microsoft Academic Search

In addition to methane (CH4) and carbon dioxide (CO2), landfill gas may contain more than 200 non-methane organic compounds (NMOCs) including C2+-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 CH4 and

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

2008-01-01

94

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

Microsoft Academic Search

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

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

2006-01-01

95

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

Microsoft Academic Search

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

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

1993-01-01

96

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

PubMed

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 and operating costs of ADC use. PMID:11525478

Haughey, R D

2001-02-01

97

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

PubMed

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

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

2010-08-31

98

Water Balance Data from the Alternative Landfill Cover Demonstration  

Microsoft Academic Search

A large-scale field demonstration comparing final landfill cover designs was constructed and is currently being monitored at Sandia National Laboratories in Albuquerque, New Mexico. Two prescriptive cover designs were constructed side-by-side with four alternative landfill covers designed for dry environments (Figure 1). The demonstration is intended to evaluate the different landfill cover designs based on their respective water balance performance,

Stephen F. Dwyer; Bruce Reavis; Gretchen Newman

99

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

PubMed

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 ?M 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?

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

2013-08-21

100

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 ...

101

Biotic methane oxidation within an instrumented experimental landfill cover  

Microsoft Academic Search

An experimental landfill cover composed of a mixture of sand and compost was installed at the St-Nicéphore landfill in Québec (Canada). The mixture was evaluated as a potential substrate to promote methane (CH4) oxidation by methanotrophic bacteria. One of the objectives of this field project was to assess the efficiency of the cover in reducing CH4 emissions. For this, both

Louis-B. Jugnia; Alexandre R. Cabral; Charles W. Greer

2008-01-01

102

SETTLEMENT AND COVER SUBSIDENCE OF HAZARDOUS WASTE LANDFILLS  

EPA Science Inventory

Numerical models using equations for linearly elastic deformation were developed to predict the maximum expected amount of settlement and cover subsidence and potential cracking of the cover by differential settlement in uniformly, horizontally layered hazardous waste landfills. ...

103

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 ...

104

On the performance of capillary barriers as landfill cover  

NASA Astrophysics Data System (ADS)

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.

Kämpf, M.; Montenegro, H.

105

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

PubMed

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

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

2009-01-01

106

Models for hydrologic design of evapotranspiration landfill covers.  

PubMed

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

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

2005-09-15

107

Analysis and Design of Evapotranspirative Cover for Hazardous Waste Landfill  

Microsoft Academic Search

A site-specific unsaturated flow investigation was undertaken for the design of an evapotranspirative ~ET! cover system at the Operating Industries, Inc. ~OII! Superfund landfill in southern California. This cover system constitutes the first ET cover approved by the US Environmental Protection Agency for construction at a Superfund site. Percolation control in an ET cover system relies on the storage of

Jorge G. Zornberg; Lester LaFountain

2003-01-01

108

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

PubMed

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

Henken-Mellies, Wolf-Ulrich; Schweizer, Andreas

2010-10-11

109

Landfill cover performance monitoring using time domain reflectometry  

SciTech Connect

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.

Neher, E.R.; Cotten, G.B. [Parsons Infrastructure & Technology Group, Inc., Idaho Falls, ID (United States); McElroy, D. [Lockheed-Martin Idaho Technologies Company, Idaho Falls, ID (United States)

1998-03-01

110

Planning document for the Advanced Landfill Cover Demonstration  

SciTech Connect

The Department of Energy and Department of Defense are faced with the closure of thousands of decommissioned radioactive, hazardous, and mixed waste landfills as a part of ongoing Environmental Restoration activities. Regulations on the closure of hazardous and radioactive waste landfills require the construction of a ``low-permeability`` cover over the unit to limit the migration of liquids into the underlying waste. These landfills must be maintained and monitored for 30 years to ensure that hazardous materials are not migrating from the landfill. This test plan is intended as an initial road map for planning, designing, constructing, evaluating, and documenting the Advanced Landfill Cover Demonstration (ALCD). It describes the goals/ objectives, scope, tasks, responsibilities, technical approach, and deliverables for the demonstration.

Hakonson, T.E. [Colorado State Univ., Fort Collins, CO (United States). Center for Ecological Risk Assessment & Management; Bostick, K.V. [Los Alamos National Lab., NM (United States). Environmental Science Group

1994-10-01

111

Attenuation of hydrogen sulfide at construction and demolition debris landfills using alternative cover materials  

Microsoft Academic Search

The attenuation of H2S emissions by various landfill cover materials was evaluated using both laboratory and field experiments. The results demonstrated that cover materials consisting of selected waste products (compost and yard trash) and soils amended with quicklime and calcium carbonate effectively attenuated H2S emissions and detectable H2S emissions were only encountered in a testing plot using a sandy soil

Qiyong Xu; Timothy Townsend; Debra Reinhart

2010-01-01

112

Measurement of microbial biomass and activity in landfill soils.  

SciTech Connect

Two complementary techniques, which have been widely used to provide a general measure of microbial biomass or microbial activity in natural soils, were evaluated for their applicability to soils from the Mallard North and Mallard Lake Landfills, DuPage County, Illinois, U.S.A. Included were: (1) a potassium sulphate extraction technique with quantification of organic carbon for measurement of microbial biomass; and (2) an arginine ammonification technique for microbial activity. Four profiles consisting of replaced soils were sampled for this study; units included topsoil (mixed mollisol A and B horizons), compacted clay cover (local calcareous Wisconsinan age glacial till), and mixed soil/refuse samples. Internally consistent results across the four profiles and good correlations with other independent indicators of microbial activity (moisture, organic matter content, nitrogen, and phosphorus) suggest that, even though these techniques were developed mainly for natural mineral soils, they are also applicable to disturbed landfill soils.

Bogner, J. E.; Miller, R. M.; Spokas, K.; Environmental Research

1995-01-01

113

Characterization of Aspen ASH, Sand and Log-Yard Waste Mixtures from an Aspen-Based Oriented Strand Board Mill for Use as an Intermediate Landfill Cover  

Microsoft Academic Search

Wood ash has a variety of uses including land application, geotechnical construction and daily and final covers for landfills. The objective of this study was to determine the relevant chemical and physical properties of selected mixtures of aspen burner-ash, log-yard waste scrapings (sandy soil plus wood waste) and a sandy soil as an intermediate landfill cover. The treatment mixtures, per

R. M. A. Block; K. C. J. van Rees

2004-01-01

114

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

PubMed

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

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

2009-09-27

115

Field Performance of Three Compacted Clay Landfill Covers  

Microsoft Academic Search

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), instru- mented drainage lysimeters for 2 to 4 yr. Initial drainage at the Iowa and California

William H. Albright; Craig H. Benson; Glendon W. Gee; Tarek Abichou; Scott W. Tyler; Steven A. Rock

2006-01-01

116

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

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

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

2009-09-29

117

Chromium in soil layers and plants on closed landfill site after landfill leachate application.  

PubMed

Landfill leachate (LL) usually contains low concentrations of heavy metals due to the anaerobic conditions in the methanogenic landfill body after degradation of easily degradable organic matter and the neutral pH of LL, which prevents mobilization and leaching of metals. Low average concentrations of metals were also confirmed in our extensive study on the rehabilitation of an old landfill site with vegetative landfill cover and LL recirculation after its treatment in constructed wetland. The only exception was chromium (Cr). Its concentrations in LL ranged between 0.10 and 2.75 mg/L, and were higher than the concentrations usually found in the literature. The objectives of the study were: (1) to understand why Cr is high in LL and (2) to understand the fate and transport of Cr in soil and vegetation of landfill cover due to known Cr toxicity to plants. The total concentration of Cr in LL, total and exchangeable concentrations of Cr in landfill soil cover and Cr content in the plant material were extensively monitored from May 2004 to September 2006. By obtained data on Cr concentration in different landfill constituents, supported with the data on the amount of loaded leachate, amount of precipitation and potential evapotranspiration (ETP) during the performance of the research, a detailed picture of time distribution and co-dependency of Cr is provided in this research. A highly positive correlation was found between concentrations of Cr and dissolved organic carbon (r=0.875) in LL, which indicates the co-transport of Cr and dissolved organic carbon through the system. Monitoring results showed that the substrate used in the experiment did not contribute to Cr accumulation in the landfill soil cover, resulting in percolation of a high proportion of Cr back into the waste layers and its circulation in the system. No negative effects on plant growth appeared during the monitoring period. Due to low uptake of Cr by plants (0.10-0.15 mg/kg in leaves and 0.05-0.07 mg/kg in stems of Salix purpurea), the estimated Cr offtake from LL by plants represented only a small proportion of the LL Cr mass load during the observation period, resulting in no dispersion of Cr into the environment through leaf drop. PMID:19138510

Zupancic, Marija; Justin, Maja Zupancic; Bukovec, Peter; Selih, Vid Simon

2009-01-09

118

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

SciTech Connect

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.

Dwyer, S.F.

1998-09-01

119

Identity of active methanotrophs in land¢ll cover soil as revealed by DNA-stable isotope probing  

Microsoft Academic Search

Aconsiderable amount ofmethane produced during decomposition of landfillwaste can be oxidized in landfill cover soil by methane-oxidizing bacteria (methanotrophs) thus reducing greenhouse gas emissions to the atmosphere. The identity of active methanotrophs in Roscommon landfill cover soil, a slightly acidic peat soil, was assessed by DNA-stable isotope probing (SIP). Landfill cover soil slurries were incubated with 13C-labelled methane and under

Levente Bodrossy; Yin Chen; Andrew C. Singer; Ian P. Thompson; James I. Prosser; J. Colin Murrell

120

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

Microsoft Academic Search

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

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

2011-01-01

121

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

PubMed

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

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

2012-01-01

122

Observations on the methane oxidation capacity of landfill soils.  

PubMed

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

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

2011-05-01

123

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

SciTech Connect

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

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

2011-05-15

124

Soil gas investigations at the Sanitary Landfill  

SciTech Connect

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

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

1992-07-01

125

Soil gas investigations at the Sanitary Landfill  

SciTech Connect

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

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

1992-07-01

126

Keep your soil covered  

Technology Transfer Automated Retrieval System (TEKTRAN)

Corn residue is being considered as a possible feedstock for biofuels production. The long-term impacts on soil health of removing this residue are not well understood. Plant material is one of the soil’s main sources of organic materials. Organic matter is a very important component of soil. It su...

127

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,...

128

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

PubMed

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

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

2012-07-07

129

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

PubMed

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

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

2011-05-01

130

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...

131

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

PubMed

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

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

2004-04-01

132

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

PubMed

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

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

2012-01-01

133

Data Quality Management Plan (DQMP) for the Alternative Landfill Cover Demonstration Project  

Microsoft Academic Search

The Alternative Landfill Cover Demonstration (ALCD) is a large-scale field test that compares the effectiveness of various landfill cover designs in dry environments. More specifically, the demonstration compares the performance of four alternative designs specifically geared for drier environments to the performance of two cover designs endorsed by the Environmental Protection Agency (EPA) for nationwide use. For a thorough comparison,

R. Aguilar; S. F. Dwyer; J. Lopez

1998-01-01

134

GEOELECTRICAL CHARACTERIZATION OF COVERED LANDFILL SITES: A PROCESS-ORIENTED MODEL AND INVESTIGATIVE APPROACH  

Microsoft Academic Search

Landfill sites commonly use the space available in disused quarries or special purpose-built structures but not all past landfill\\u000a operations were adequately controlled or documented such that the site boundaries, and the type and volume of fill are unknown\\u000a in some old covered landfill sites. Even in controlled sites, the final form and depth extent of the landfill may not

Maxwell Meju

135

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

Microsoft Academic Search

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

Gerald L. Peace; Timothy James Goering; Michael David McVey; David James Borns

2003-01-01

136

Scaling methane oxidation: from laboratory incubation experiments to landfill cover field conditions.  

PubMed

Evaluating field-scale methane oxidation in landfill cover soils using numerical models is gaining interest in the solid waste industry as research has made it clear that methane oxidation in the field is a complex function of climatic conditions, soil type, cover design, and incoming flux of landfill gas from the waste mass. Numerical models can account for these parameters as they change with time and space under field conditions. In this study, we developed temperature, and water content correction factors for methane oxidation parameters. We also introduced a possible correction to account for the different soil structure under field conditions. These parameters were defined in laboratory incubation experiments performed on homogenized soil specimens and were used to predict the actual methane oxidation rates to be expected under field conditions. Water content and temperature corrections factors were obtained for the methane oxidation rate parameter to be used when modeling methane oxidation in the field. To predict in situ measured rates of methane with the model it was necessary to set the half saturation constant of methane and oxygen, K(m), to 5%, approximately five times larger than laboratory measured values. We hypothesize that this discrepancy reflects differences in soil structure between homogenized soil conditions in the lab and actual aggregated soil structure in the field. When all of these correction factors were re-introduced into the oxidation module of our model, it was able to reproduce surface emissions (as measured by static flux chambers) and percent oxidation (as measured by stable isotope techniques) within the range measured in the field. PMID:21196106

Abichou, Tarek; Mahieu, Koenraad; Chanton, Jeff; Romdhane, Mehrez; Mansouri, Imane

2010-12-31

137

Seismic stability and permanent displacement of landfill cover systems  

Microsoft Academic Search

A set of equations are formulated to determine the seismic stability and permanent displacement of cover soil in a solid-waste containment system. The formulation considers a two-part wedge mechanism with the soil-geosynthetic interface acting as the plane of weakness. In the absence of seismic forces, these equations degenerate to those proposed by Koerner and Hwu. Parametric studies indicate that the

Hoe I. Ling; Dov Leshchinsky

1997-01-01

138

Effect of intermediate soil cover on municipal solid waste decomposition.  

PubMed

A complex series of chemical and microbiological reactions is initiated with the burial of refuse in a sanitary landfill. At the end of each labour day, the municipal solid wastes (MSW) are covered with native soil (or an alternative material). To investigate interaction between the intermediate cover and the MSW, five sets of columns were set up, one packed with refuse only, and four with a soil-refuse mixture (a clay loam, an organic-rich peaty soil, a well limed sandy soil and a chalky soil). The anaerobic degradation over 6 months was followed in terms of leachate volatile fatty acids, chemical oxygen demand, pH and ammoniacal-N performance. Results suggest that the organic-rich peaty soil may accelerate the end of the acidogenic phase. Clay appeared not to have a significant effect on the anaerobic degradation process. PMID:14531450

Márquez-Benavides, L; Watson-Craik, I

2003-01-01

139

Geotechnical properties of paper mill sludges for use in landfill covers  

SciTech Connect

This study investigates the geotechnical properties of seven paper mill sludges. Paper mill sludges have a high water content and a high degree of compressibility and behave like a highly organic soil. Consolidation tests reveal a large reduction in void ratio and high strain values that are expected due to the high compressibility. Triaxial shear-strength tests conducted on remolded and undisturbed samples showed variations in the strength parameters resulting from the differences in sludge composition (i.e., water content and organic content). Laboratory permeability tests conducted on in-situ specimens either met the regulatory requirement for the permeability of a landfill cover or were very close. With time, consolidation and dewatering of the paper sludge improved the permeability of cover. Freezing and thawing cycles increased the sludge permeability about one to two orders of magnitude. Maximum permeability changes occurred within 10 freeze and thaw cycles.

Moo-Young, H.K. [Morgan State Univ., Baltimore, MD (United States). Dept. of Civil Engineering; Zimmie, T.F. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Civil and Environmental Engineering

1996-09-01

140

Assessing the Performance of a Cold Region Evapotranspiration Landfill Cover Using Lysimetry and Electrical Resistivity Tomography  

Microsoft Academic Search

In order to test the efficacy of a 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×10m×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

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

2012-01-01

141

Characterization of methane, benzene and toluene-oxidizing consortia enriched from landfill and riparian wetland soils.  

PubMed

The microbial oxidations of methane (M) and volatile organic compounds (VOCs) were compared with those of M and VOCs alone after enriching soil samples with M and/or VOCs. Landfill cover and riparian wetland soils from which M and VOCs were simultaneously emitted were selected as representative samples. Benzene (B) and toluene (T) were employed as the model VOCs. With the landfill soil consortia, the rate of M oxidation decreased from 4.15-5.56 to 2.26-3.42 ?mol g-dry soil(-1)h(-1) in the presence of both B and T, but with the wetland soil consortia the rate of M oxidation (3.09 ?mol g-dry soil(-1)h(-1)) in the mixture of M as well as both B and T was similar to that of M alone (3.04 ?mol g-dry soil(-1)h(-1)). Compared with the methanotrophic community with M alone, the portion of type II methanotrophs was greater in the landfill consortia; whereas, the proportion in wetland consortia was less in the presence of both B and T. The oxidations of B and T were stimulated by the presence of M with both the landfill and wetland consortia. There were no correlations between the oxidation rate of M and those of B and T with the gene copy numbers of pmoA and tmoA responsible for the oxidations. PMID:20832163

Lee, Eun-Hee; Park, Hyunjung; Cho, Kyung-Suk

2010-08-18

142

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

Microsoft Academic Search

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

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

1997-01-01

143

Boron in irrigation water and its interactions with soil and plants: an example of municpal landfill leachate reuse  

Microsoft Academic Search

In several countries, leachate is successfully treated by recirculation to the vegetated landfill cover, as it contains several micro and macronutrients for plant growth. However, the proportion and concentration of some parameters can negatively affect the plant growth and soil quality in the case of high leachate input. The presented research discusses B in leachate and its interactions with soil

Maja ZUPAN?I? JUSTIN

144

Water Balance and Effectiveness of Mineral Landfill Covers – Results of Large Lysimeter Test-Fields  

Microsoft Academic Search

Landfills are provided with cover systems in order to separate the waste from the environment and in order to prevent percolation\\u000a of precipitation and recharge of leachate. The layers of a landfill cover system (restoration profile, drainage layer, compacted\\u000a clay liner – CCL) have to be specifically designed for long-lasting effectiveness. Special care has to be taken to prevent\\u000a the

Wolf Ulrich Henken-Mellies

145

Reevaluating the role of soil layers in landfill construction  

SciTech Connect

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.

Roberts, M.; Larky, A. [Burns & McDonnell Waste Consultants Inc., Overland Park, KS (United States)

1996-05-01

146

Field Performance of Alternative Landfill Covers Vegetated with Cottonwood and Eucalyptus Trees  

Microsoft Academic Search

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 × 14 m) lined lysimeters at the Leon County Solid Waste management facility in Tallahassee, Florida. Additional unlined test sections were also constructed and

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

2012-01-01

147

RULE-BASED SYSTEM FOR EVALUATING FINAL COVERS FOR HAZARDOUS WASTE LANDFILLS  

EPA Science Inventory

This paper describes how rules are-used as a knowledge representation formalism in an expert system called F-Cover. -Cover assists RCRA permit reviewers in evaluating performance standards for final covers at hazardous waste landfills. he paper shows how a goal tree for final cov...

148

Suitability of Hydrologic Evaluation of Landfill Performance (HELP) model of the US Environmental Protection Agency for the simulation of the water balance of landfill cover systems  

Microsoft Academic Search

Cover systems are widely used to safeguard landfills and contaminated sites. The evaluation of the water balance is crucial\\u000a for the design of landfill covers. The Hydrologic Evaluation of Landfill Performance (HELP) model of the US Environmental\\u000a Protection Agency was developed for this purpose. This paper discusses some limitations of version 2 of this model and some\\u000a operational difficulties for

K. Berger; S. Melchior; G. Miehlich

1996-01-01

149

Digested sewage sludge solidification by converter slag for landfill cover  

Microsoft Academic Search

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

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

2005-01-01

150

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

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.

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

1994-04-01

151

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

Microsoft Academic Search

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

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

2005-01-01

152

Numerical Analysis of Moisture Transport in Evapotranspiration Landfill Cover with Capillary Barrier  

Microsoft Academic Search

Based on the mechanism of unsaturated seepage flow, a one-dimensional numerical model is developed to simulate moisture transport in capillary evapo-transpiration (ET) landfill covers in response to precipitation and ET. The calculated net infiltration is input into the model as boundary conditions to simulate moisture transport of a capillary ET cover on the base of precipitation and ET data of

Qing-lei Yang; Qing Yang; Jin-li Zhang; Mao-tian Luan

153

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

SciTech Connect

Cobble mulch and composted biosolids, greenwaste, and dairy manure were added to arid soil in an attempt to improve plant establishment and production, minimize erosion, increase evapotranspiration, and reduce leaching. Twenty-four plots (10 x 10 m) were established in a completely randomized block design (8 treatments, 3 plots per treatment). Treatments included (1) non-irrigated control, (2) irrigated control, (3) non-irrigated greenwaste compost (2.5 yd{sup 3} per plot), (4) irrigated greenwaste compost (5 yd{sup 3} per plot), (5) non-irrigated biosolids compost (2.5 yd{sup 3} per plot), (6) irrigated biosolids compost (5 yd{sup 3} per plot), (7) cobble-mulch, and (8) non-irrigated dairy manure compost (2.5 yd{sup 3} per plot). Soil samples were collected from each plot for laboratory analyses to assess organic matter contents, macro-nutrient levels and trace metal contents, and nitrogen mineralization potential. All plots were seeded similarly with approximately equal portions of cool and warm season native grasses. The organic composts (greenwaste, biosolids, dairy manure) added to the soils substantially increased soil organic matter and plant nutrients including total nitrogen and phosphorus. However, the results of a laboratory study of the soils' nitrogen mineralization potential after the application of the various composts showed that the soil nitrogen-supplying capability decreased to non-amended soil levels by the start of the second growing season. Thus, from the standpoint of nitrogen fertilizer value, the benefits of the organic compost amendments appear to have been relatively short-lived. The addition of biosolids compost, however, did not produce significant changes in the soils' copper, cadmium, lead, and zinc concentrations and thus did not induce adverse environmental conditions due to excessive heavy metal concentrations. Supplemental irrigation water during the first and second growing seasons did not appear to increase plant biomass 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.

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

2000-02-01

154

Sanitary Landfill Leachate Travel in Various Soil Media - a Bibliography.  

National Technical Information Service (NTIS)

A survey of the literature was conducted in order to aid in determining how far technology had progressed toward the attainment of a capability to predict the various distances that sanitary landfill leachates must travel in different soil media before th...

W. T. Emery

1971-01-01

155

Methane flux and oxidation at two types of intermediate landfill covers  

Microsoft Academic Search

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 45cm thick

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

2006-01-01

156

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

SciTech Connect

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 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{sup -2}) to year 2 (794 g m{sup -2}) and an increase for the I plant mixture from year 1 (644 g m{sup -2}) to year 2 (1314 g m{sup -2}). Over the 2-year period, the mean annual rates of percolation for the covers with the M and I plant mixtures were 7 and 8 cm yr{sup -1}, which are below the OEPA standard. The results suggest the application of ET covers be extended to northwest Ohio and other humid regions.

Barnswell, Kristopher D., E-mail: kristopher.barnswell2@rockets.utoledo.edu [Department of Environmental Sciences, University of Toledo, Lake Erie Center, 6200 Bayshore Rd., Oregon, OH 43616 (United States); Dwyer, Daryl F., E-mail: daryl.dwyer@utoledo.edu [Department of Environmental Sciences, University of Toledo, 2801 W. Bancroft, Mail Stop 604, Toledo, OH 43606 (United States)

2012-12-15

157

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

PubMed

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

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

2013-03-11

158

Landfills in the year 2000  

SciTech Connect

The 21st century landfill will have the proper public and customer image from the environmental standpoint. The landfill of the 21st century will provide diverse services right at the landfill. You will not only have burial of waste, but a bioremediation pad for handling certain petro-chemical soils and a reuse area for concrete and rubble. Landfills will reuse special wastes. The industry now has more than seven specialized industrial wastes approved for landfill cover. So, instead of spending money for landfill cover or alternative cover like foam, landfills will actually get paid for the landfill cover. The landfill of the 21st century will have some level of recycling and composting. The sites will broaden their service base to make sure that the customer will be able to bring the wide variety of waste to one place. All of this technology will be designed to function at the landfill to keep waste out of the landfill. From a regulatory standpoint, obviously 21st century landfills will exceed all of the standards. It will be a given that the landfill will have liners, leachate collection, leachate treatment, and gas recovery and, probably, reuse. The 21st century landfill will receive a very different waste type. It will have less municipal solid waste and a greater volume of special waste-compatible, nonhazardous waste.

Glebs, B. (Superior Environmental Services, Madison, WI (United States))

1994-03-01

159

Global climate changes and the soil cover  

NASA Astrophysics Data System (ADS)

The relationships between climate changes and the soil cover are analyzed. The greenhouse effect induced by the rising concentrations of CO2, CH4, N2O, and many other trace gases in the air has been one of the main factors of the global climate warming in the past 30-40 years. The response of soils to climate changes is considered by the example of factual data on soil evolution in the dry steppe zone of Russia. Probable changes in the carbon cycle under the impact of rising CO2 concentrations are discussed. It is argued that this rise may have an effect of an atmospheric fertilizer and lead to a higher productivity of vegetation, additional input of organic residues into the soils, and activation of soil microflora. Soil temperature and water regimes, composition of soil gases, soil biotic parameters, and other dynamic soil characteristics are most sensitive to climate changes. For the territory of Russia, in which permafrost occupies more than 50% of the territory, the response of this highly sensitive natural phenomenon to climate changes is particularly important. Long-term data on soil temperatures at a depth of 40 cm are analyzed for four large regions of Russia. In all of them, except for the eastern sector of Russian Arctic, a stable trend toward the rise in the mean annual soil temperature. In the eastern sector (the Verkhoyansk weather station), the soil temperature remains stable.

Kudeyarov, V. N.; Demkin, V. A.; Gilichinskii, D. A.; Goryachkin, S. V.; Rozhkov, V. A.

2009-09-01

160

Functional Environmental Genomics of a Municipal Landfill Soil  

PubMed Central

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.

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

2012-01-01

161

Functional environmental genomics of a municipal landfill soil.  

PubMed

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

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

2012-05-16

162

Flux estimates from soil methanogenesis and methanotrophy: Landfills, rice paddies, natural wetlands and aerobic soils  

Microsoft Academic Search

Present and future annual methane flux estimates out of landfills, rice paddies and natural wetlands, as well as the sorption capacity of aerobic soils for atmospheric methane, are assessed. The controlling factors and uncertainties with regard to soil methanogenesis and methanotrophy are also briefly discussed.

Pascal Boeckx; OSWALD VAN CLEEMPUT

1996-01-01

163

Effect of heavy metals on microbial biomass and activities in century old landfill soil.  

PubMed

A study was conducted to determine the effect of metals on soil microbial biomass and activities in landfill soils as well as normal background soil. The microbial biomass and activities were consistently higher in the landfill soils than in the background soil. Significant positive correlations existed between the microbial parameters and soil organic carbon. The landfill soils contained higher concentrations of metals (iron, manganese, copper, cadmium, lead and zinc) than did the background soil. Microbial parameters were negatively correlated with the metals, with inhibition increasing with the bioavailability of the metals. It is suggested that the metals affected microbial biomass and activities by behaving synergistically or additively with each other. Although the landfill soils had higher microbial biomass and activities than the background soil, due to higher organic matter content, the ratios of microbial parameters/organic carbon indicated that inhibition of microbial growth and activities had occurred due to metal stress. PMID:17370129

Bhattacharyya, P; Mitra, A; Chakrabarti, K; Chattopadhyay, D J; Chakraborty, A; Kim, K

2007-03-17

164

Assessment of an active dry barrier for a landfill cover system  

SciTech Connect

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.

Stormont, J.C. [Sandia National Labs., Albuquerque, NM (United States); Ankeny, M.D.; Burkhard, M.E.; Tansey, M.K.; Kelsey, J.A. [Stephens (Daniel B.) and Associates, Inc., Albuquerque, NM (United States)

1994-03-01

165

Snow cover and soil moisture in mountains  

NASA Astrophysics Data System (ADS)

Soil moisture is an important parameter of the climate system. It constrains evapotranspiration of plants and it functions as a storage of water, giving it an economic value, e.g. for agriculture. Furthermore, soil moisture is an important factor for predicting flood risk. In mountainous areas with a seasonal snow cover, the spatial distribution of snow depth is strongly influencing the spatial variation of soil moisture. To assess potential flooding situations during snow melt and rain on snow events in particular but for any heavy precipitation event in the mountains, it is important to understand the influence of the snow cover on soil status with respect to liquid and solid water. Only if this is known, the reaction of the soil i.e. amount of runoff, storage or melt, on additional water input can be assessed. For an operational assessment of the soil moisture state in the Swiss Alps at 140 measurement sites for snow and avalanche forecasting (IMIS network), the SNOWPACK model has been extended with a soil module, solving the Richards equation for the matrix flow. The modelling is validated with vertical profile measurements of soil moisture at meteorological stations in an Alpine catchment near Davos, Switzerland. It was found that the combination of a physical based snowpack model with a Richards equation solver seems to provide an adequate description of soil moisture fluctuations, especially in near surface layers. Soil moisture fluctuations, both measured and modelled, are strongly reduced when a snow cover is present. The measurements also revealed a strong increase in soil moisture, accompanied by a daily cycle in soil moisture during snow melt, extending down to 120cm depth. When soil properties from literature were assumed for the soil type in the vertical profile, the daily cycle in the model during snow melt was restricted mainly to the top layers, while observations show also a reaction in deeper layers. These observations are consistent with the assumption of the existence of preferential flow paths, which are not modelled by the Richards equation. This discrepancy between observations and model results during the melt phase may cause an underestimation of the soil storage capacity and an overestimation of the surface run-off in the model.

Wever, N.; Lehning, M.

2012-04-01

166

Alternative Landfill Cover and Monitoring Systems for Landfills in Arid Environments  

Microsoft Academic Search

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

S. E. Rawlinson

2002-01-01

167

Feasibility Study, Primary Designs and Development of Alternative Evapotranspiration Covers for Landfills and Waste Dump Sites in Tropical Locations  

Microsoft Academic Search

People generate a large and ever-increasing volume of waste, which originates in rural and urban areas, industrial operations and other activities. In spite of waste recycling, which is the solution to the huge amount of solid waste, a large part of it is deposited into landfills, dumps, etc.Landfills are, at present, the most widely used waste disposal facilities. Final cover

Francisco Jose Escobar

2010-01-01

168

Methane flux and oxidation at two types of intermediate landfill covers  

SciTech Connect

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.

Abichou, Tarek [Department of Civil and Environmental Engineering, Florida A and M University, Florida State University, College of Engineering, Tallahassee, FL 32310 (United States)]. E-mail: abichou@eng.fsu.edu; Chanton, Jeffery [Department of Oceanography, Florida State University, Tallahassee, FL 32306 (United States); Powelson, David [Department of Oceanography, Florida State University, Tallahassee, FL 32306 (United States); Fleiger, Jill [Department of Oceanography, Florida State University, Tallahassee, FL 32306 (United States); Escoriaza, Sharon [Department of Civil and Environmental Engineering, Florida A and M University, Florida State University, College of Engineering, Tallahassee, FL 32310 (United States); Lei, Yuan [Department of Civil and Environmental Engineering, Florida A and M University, Florida State University, College of Engineering, Tallahassee, FL 32310 (United States); Stern, Jennifer [Department of Geology, Florida State University, Tallahassee, FL 32306 (United States)

2006-07-01

169

EFFECT OF SYNTHETIC LEACHATE ON THE HYDRAULIC CONDUCTIVITY OF CLAYEY SOIL IN URMIA CITY LANDFILL SITE  

Microsoft Academic Search

The effect of synthetic leachate on the hydraulic conductivity of a clayey soil in the Urmia city landfill site, Iran, was investigated using a triaxial permeability apparatus. The bladder accumulators were fabricated for flexible wall triaxial permeability apparatus to facilitate synthetic leachate permeation in the apparatus. The landfill soil was tested and classified as silty clayey sand (SM-SC) and did

K. BADV; A. OMIDI

170

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

PubMed

The ability of municipal waste compost as a daily cover material to reduce the odorous emissions associated with landfill surfaces was investigated. Trials were carried out using landfill gas, a certified sulphurous gas mix and ambient air as a control. Odorous gas was passed through portable test column filled with compost at different densities (590 kg/m3 and 740 kg/m3). Gas samples were taken from the inlet, outlet and at varying column depths and examined using a combination of sensory analysis (olfactometry) and a novel analytical method (Transportable Selected Ion Flow Tube--TSIFT). Results for the trials using landfill gas showed a 69% odour reduction (OU/m3) through the column for compost with a bulk density of 590 kg/m3, and a reduction of 97% using compost with a bulk density of 740 kg/m3. TSIFT analysis showed an overall decrease in the concentration of terpenes, and sulphurous compounds in the outlet gas from the column for both bulk densities. No significant trend could be identified for the concentrations at different depths within the column. Results show the ability of compost to reduce landfill odours under differing conditions. The inconclusive data provided by TSIFT analysis may be due to the analysis of compounds that are not contributing to odour, and thus highlights the potential for synergetic effects and the importance of sensory measurement when examining odorous emissions. PMID:15701404

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

2005-05-01

171

Use of a biologically active cover to enhance landfill methane oxidation  

NASA Astrophysics Data System (ADS)

The emplacement of a biocover composed of a glass dispersion layer and a compost layer at the Tallahassee MSW Landfill significantly reduced methane emissions (by a factor of 10) and doubled the oxidation of methane compared to a non-treated control area of the landfill. The biocover became more effective than the control in oxidizing methane three months after its initial emplacement. Percent oxidation of methane was calculated using the carbon isotopic composition and concentration of methane emitted at the surface of the landfill. Over the one-year period of study, the difference in methane emission rate and methane oxidation percentage in the control and the biocover were statistically significant (p < 0.001). Following the initial three-month curing period, the mean oxidation for the biocover was 38%, and the mean oxidation for the control was 19%. Following the three month curing period 29 negative fluxes and 27 zero fluxes were observed in the biocover, while only 6 negative fluxes and 22 zero fluxes were onserved in the control area. Negative fluxes indicate uptake of atmospheric methane. If these zero and negative fluxes are assumed to represent 100% oxidation then the mean percent oxidation for the biocover and control areas increase to 56% and 39% respectively. Individual flux chambers showed a negative correlation between soil moisture and oxidation and a positive correlation between soil temperature and oxidation. Neither flux nor oxidation exhibited a distinct seasonality, perhaps due to relatively warm temperatures throughout the year or the effects of soil moisture buffering the effects of temperature.

Stern, J. C.; Chanton, J.; Abichou, T.; Powelson, D.; Yuan, L.; Bogner, J.

2005-12-01

172

Chromium in soil layers and plants on closed landfill site after landfill leachate application  

Microsoft Academic Search

Landfill leachate (LL) usually contains low concentrations of heavy metals due to the anaerobic conditions in the methanogenic landfill body after degradation of easily degradable organic matter and the neutral pH of LL, which prevents mobilization and leaching of metals. Low average concentrations of metals were also confirmed in our extensive study on the rehabilitation of an old landfill site

Marija Zupan?i?; Maja Zupan?i? Justin; Peter Bukovec; Vid Simon Šelih

2009-01-01

173

Use of Impervious Covers and Carbon Adsorption for the Control of Leachate Production in Municipal Landfills.  

National Technical Information Service (NTIS)

The most popular method for the disposal of solid wastes in the United States is by landfill. A proper landfill, termed sanitary landfill, is one which is located, designed, and operated to minimize or eliminate environmental impact. One potential environ...

R. C. Carmichael

1979-01-01

174

Assessment of Heavy Metals from Landfill Leachate Contaminated to Soil: A Case Study of Kham Bon Landfill, Khon Kaen Province, NE Thailand  

Microsoft Academic Search

The distribution of heavy metals in landfill leachate contaminated to soil was investigated. Soil samples were collected at different times of the year as well as at various locations and depths in and around the landfill and throughout the contaminated area. The physical and chemical properties of the samples were analyzed. The results indicated that the heavy metals, namely Cd,

Udomporn Chuangcham; Wanpen Wirojanagud; Punya Charusiri; William Milne-Home; Rungruang Lertsirivorakul

2008-01-01

175

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

SciTech Connect

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 once in ten year events, respectively, whereas corresponding values for runoff were 13% and 16%; these changes were accompanied by corresponding decreases in evapotranspiration, which accounted for 86% and only 78% of the precipitation occurring on the average and once in ten year even~ respectively.

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

1998-09-01

176

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

PubMed

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

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

2010-12-18

177

Consuming un-captured methane from landfill using aged refuse bio-cover.  

PubMed

A novel simulated bio-cover was developed to facilitate the biological methane oxidation process using aged refuse and aged sludge from landfill. It was found that 78.7% and 66.9% of CH(4) could be removed, with the aged refuse: aged sludge (w/w%) ratio of 7:3 and 6:4 in bio-cover system, respectively. The maximum CH(4) removal rate could reach 100%, when the aged refuse with the disposal time more than 14 years were applied in bio-cover. Some controlled factors for the methanotrophic activity, i.e. moisture, Eh and organic matter content, were also investigated. It was found that CH(4) oxidation rate increased greatly, when the moisture content and organic matter were increased from 6.0%, 4.8% to 8.0%, 9.5%, respectively. The optimum conditions for this bio-cover system was found to be as follows: aged refuse: aged sludge ratio of 7:3, the moisture content of 8-9%, Eh of 104-108 mV and organic matter of 9.5%. PMID:21078552

Lou, Ziyang; Wang, Li; Zhao, Youcai

2010-10-23

178

Snow Cover and Winter Soil Temperatures at St. Paul, Minnesota.  

National Technical Information Service (NTIS)

The objectives of the study of winter soil temperatures under a sod cover were to show the configuration of the soil isotherm patterns, in particular that of 0C, and to determine which soil thermal characteristics can be estimated by the snow cover. The t...

D. G. Baker

1971-01-01

179

Remote sensing of crop residue cover and soil tillage intensity  

Microsoft Academic Search

Crop residues on the soil surface reduce soil erosion and affect water infiltration, evaporation, and soil temperatures. Crop residues also influence the flow of nutrients, carbon, water, and energy in agricultural ecosystems. Current methods of measuring crop residue cover are inadequate for monitoring large areas. One promising remote sensing approach for discriminating crop residues from soil is based on a

C. S. T. Daughtry; P. C. Doraiswamy; A. L. Russ

2003-01-01

180

PROPERTIES OF DIFFERENT SIZE SCRAP TIRE SHREDS: IMPLICATIONS ON USING AS DRAINAGE MATERIAL IN LANDFILL COVER SYSTEMS  

Microsoft Academic Search

Various engineering properties must be known to assess the feasibility of using shredded scrap tires as drainage material in landfill cover systems. These properties include unit weight, hydraulic conductivity, compressibility, shear strength, and interface shear strength. This paper summarizes the engineering properties of tire shreds based reported studies and evaluates the variation of these properties with the size of tire

Krishna R. Reddy; Aravind Marella

2001-01-01

181

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

Microsoft Academic Search

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)

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

1998-01-01

182

Heavy metal content in soil reclaimed from a municipal solid waste landfill.  

PubMed

Residues reclaimed from a municipal solid waste (MSW) landfill were characterized for the concentrations of a number of heavy metals. The residue fractions analyzed included a fine fraction (<0.425 mm), an intermediate fraction (>0.425 and <6.3 mm) and a fraction consisting of paper products that could ultimately degrade to a smaller size. The intermediate fraction appeared to be organic in nature, while the fine fraction was more soil-like. In general, the metal concentrations were greatest in the intermediate fraction and lowest in the fine fraction. The effect of sample age on the elemental content was also investigated. The concentrations of several elements were greater in older samples (sample approximately 8 years in age) when compared to newer samples (sample approximately 3 years in age). Limitations associated with the land application of residual soil (composed of the fine and intermediate fractions) were assessed by comparing measured concentrations to regulatory threshold values. In general, most metal concentrations were below regulatory thresholds for use in unrestricted settings. At the concentrations measured, however, several elements might limit reuse options, depending on which regulatory threshold serves as a benchmark. Elevated concentrations of arsenic presented the greatest limitation with respect to common US thresholds while elevated cadmium concentrations presented the greatest limitation when compared to UK thresholds. The source of the arsenic was determined to be the waste, not the cover soil. PMID:15681176

Jain, Pradeep; Kim, Hwidong; Townsend, Timothy G

2005-01-01

183

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

PubMed

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

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

2003-10-15

184

Laboratory study of landfill leachate effect on resistivity in unsaturated soil using cone penetrometer  

Microsoft Academic Search

Electrical resistivity of soils is dependent upon various factors, including soil type, water content, saturation and pore fluid property. Experimental works have been performed to investigate the relationship between electrical resistivity and unsaturated subsurface conditions with varying physical property and landfill leachate contamination. The moisture density can be the most effective indicator for describing the relationship between electrical resistivity and

G. L. Yoon; M. Oh

2002-01-01

185

Molecular detection and direct enumeration of methanogenic Archaea and methanotrophic Bacteria in domestic solid waste landfill soils.  

PubMed

Methane oxidizing and producing activities of cover soil (10, 30 cm depth) and burial waste (1, 3 m depth) were evaluated: top cover soil (10 cm) had the highest methane oxidizing activity, while 1 m depth buried waste showed the highest methane producing potential. All the sequences of the 1 m sample were found to be closely related to 16S rDNAs of mainly hydrogenotrophic methanogens known, such as genera Methanosarcina, Methanoculleus, and Methanobacterium. We developed a modified fluorescence in situ hybridization (FISH) direct counting method for landfill samples, resulting in the detection of approx. 1% of total cells as archaeal cells (presumably methanogens). However, probe-positive cells could not be found with probes for methanotrophs by the methods. PMID:14571983

Chen, Ann-Cheng; Ueda, Kumiko; Sekiguchi, Yuji; Ohashi, Akiyoshi; Harada, Hideki

2003-09-01

186

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

PubMed

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

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

2009-01-07

187

Effect of lime-stabilized sludge as landfill cover on refuse decomposition  

Microsoft Academic Search

Increased quantities of wastewater-treatment sludge coupled with more stringent regulations make it important to develop alternatives for residuals management. The use of a mixture of anaerobically digested, lime-stabilized wastewater sludge (LSS) and soil as a cover material was evaluated for its effect on refuse decomposition and leachate quality. Tests were conducted in 4-L reactors filled with shredded refuse an operated

Rodney D. Rhew; Morton A. Barlaz

1995-01-01

188

Assessment of Heavy Metals from Landfill Leachate Contaminated to Soil: A Case Study of Kham Bon Landfill, Khon Kaen Province, NE Thailand  

NASA Astrophysics Data System (ADS)

The distribution of heavy metals in landfill leachate contaminated to soil was investigated. Soil samples were collected at different times of the year as well as at various locations and depths in and around the landfill and throughout the contaminated area. The physical and chemical properties of the samples were analyzed. The results indicated that the heavy metals, namely Cd, Cr, Pb, Cu and Zn were significant concentrations in the soil within a radius of 2,000 m from the landfill. The Spearman`s rank correlation coefficient indicated that the appearance of high Cation exchange capacity, clay content and organic matter are statistically correlated with the high heavy metals accumulation. Moreover, the Fe and Mn oxide/oxyhydroxides plays important role in controlling heavy metals sink in soil as pointed out by the spearman ‘s rank correlation coefficient which corresponding to the soil type, red loess with high iron oxide, in the study area.

Chuangcham, Udomporn; Wirojanagud, Wanpen; Charusiri, Punya; Milne-Home, William; Lertsirivorakul, Rungruang

189

RCRA (Resource Conservation and Recovery Act) Guidance Document: Landfill Design, Liner Systems and Final Cover.  

National Technical Information Service (NTIS)

The guidance document presents landfill design specifications which the Agency believes comply with the design and operating requirements of 264.301(A), and the closure requirements of 264.310(A) of the RCRA landfill regulations. These regulations have be...

1982-01-01

190

Modeling soil depth from topographic and land cover attributes  

NASA Astrophysics Data System (ADS)

Soil depth is an important input parameter in hydrological and ecological modeling. Presently, the soil depth data available in national soil databases (STATSGO and SSURGO) from the Natural Resources Conservation Service are provided as averages within generalized land units (map units). Spatial uncertainty within these units limits their applicability for distributed modeling in complex terrain. This work reports statistical models for prediction of soil depth in a semiarid mountainous watershed that are based upon the relationship between soil depth and topographic and land cover attributes. Soil depth was surveyed by driving a rod into the ground until refusal at locations selected to represent the topographic and land cover variation in the Dry Creek Experimental Watershed near Boise, Idaho. The soil depth survey consisted of a model calibration set, measured at 819 locations over 8 subwatersheds representing topographic and land cover variability and a model testing set, measured at 130 more broadly distributed locations in the watershed. Many model input variables were developed for regression to the field data. Topographic attributes were derived from a digital elevation model. Land cover attributes were derived from Landsat remote sensing images and high-resolution aerial photographs. Generalized additive and random forests models were developed to predict soil depth over the watershed. They were able to explain about 50% of the soil depth spatial variation, which is an important improvement over the soil depth extracted from the SSURGO national soil database.

Tesfa, Teklu K.; Tarboton, David G.; Chandler, David G.; McNamara, James P.

2009-10-01

191

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

Microsoft Academic Search

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

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

2008-01-01

192

Methanotroph diversity in landfill soil: Isolation of novel type I and type II methanotrophs whose presence was suggested by culture-independent 16S ribosomal DNA analysis  

Microsoft Academic Search

The diversity of the methanotrophic community in mildly acidic landfill cover soil was assessed by three methods: two culture-independent molecular approaches and a traditional culture-based approach. For the first of the molecular studies, two primer pairs specific for the 16S rRNA gene of validly published type I (including for former type X) and type II methanotrophs were identified and tested.

MARK G. WISE; J VAUN MCARTHUR; L. J. Smimkets

1999-01-01

193

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

PubMed

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

Kwon, O; Park, J

2006-11-01

194

Quantifying the effect of oxidation on landfill methane emissions  

Microsoft Academic Search

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

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

1996-01-01

195

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

PubMed

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

Christophersen, M; Kjeldsen, P

2001-12-01

196

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

PubMed

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

Christophersen, M; Kjeldsen, P

2001-04-01

197

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

PubMed

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

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

2006-04-18

198

Treatment of landfill leachate by using lateritic soil as a natural coagulant.  

PubMed

In this research, the capability of lateritic soil used as coagulant for the treatment of stabilized leachate from the Penang-Malaysia Landfill Site was investigated. The evaluation of lateritic soil coagulant in comparison with commercialized chemical coagulants, such as alum, was performed using conventional jar test experiments. The optimum pH and coagulant dosage were identified for the lateritic soil coagulant and the comparative alum coagulant. It was found that the application of lateritic soil coagulant was quite efficient in the removal of COD, color and ammoniacal-nitrogen content from the landfill leachate. The optimal pH value was 2.0, while 14 g/L of lateritic soil coagulant was sufficient in removing 65.7% COD, 81.8% color and 41.2% ammoniacal-nitrogen. Conversely, the optimal pH and coagulant dosage for the alum were pH 4.8 and 10 g/L respectively, where 85.4% COD, 96.4% color and 47.6% ammoniacal-nitrogen were removed from the same leachate sample. Additionally, the Sludge Volume Index (SVI) ratio of alum and lateritic soil coagulant was 53:1, which indicated that less sludge was produced and was an environmentally friendly product. Therefore, lateritic soil coagulant can be considered a viable alternative in the treatment of landfill leachate. PMID:22964042

Syafalni; Lim, Han Khim; Ismail, Norli; Abustan, Ismail; Murshed, Mohamad Fared; Ahmad, Anees

2012-09-08

199

Landfill leachate treatment with a novel process: Anaerobic ammonium oxidation (Anammox) combined with soil infiltration system  

Microsoft Academic Search

A novel combined process was proposed to treat municipal landfill leachate with high concentrations of ammonium and organics. This process consisted of a partial nitritation reactor (PNR), an anaerobic ammonium oxidation (Anammox) reactor (AR) and two underground soil infiltration systems (USIS-1 and USIS-2). Based on the optimum operating conditions obtained from batch tests of individual unit, the combined process was

Zhu Liang; Junxin Liu

2008-01-01

200

Genome Sequence of Pectin-Degrading Alishewanella agri, Isolated from Landfill Soil  

PubMed Central

Alishewanella agri BL06T (= KCTC 22400T = JCM 15597T) was isolated from landfill soil in Pohang, South Korea. A. agri showed the ability to degrade pectin, a structural heteropolysaccharide present in the cell wall of plants. Here we report the genome sequence of Alishewanella agri BL06T, the second sequenced strain in the genus Alishewanella.

Kim, Jisun; Jung, Jaejoon; Sung, Jung-Suk; Chun, Jongsik

2012-01-01

201

Changes in Soil Water Storage in Winter Fallowed and Cover Cropped Soils  

Microsoft Academic Search

The use of winter cover crops to improve the productivity and sustainability of agroecosystems in California has increased during the last decade. Little information exists however, on water use by winter cover crops. This 3-year study was conducted in the Central Valley of California to quantify changes in water storage in winter fallowed and cover cropped soils. Soil water depletions

J. P. Mitchell; D. W. Peters; C. Shennan

1999-01-01

202

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

SciTech Connect

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.

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

1992-12-01

203

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

SciTech Connect

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

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

1989-12-01

204

Cover crops effectiveness for soil erosion control in Sicilian vineyard  

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

205

Microwave Backscatter Dependence on Surface Roughness, Soil Moisture, and Soil Texture: Part II-Vegetation-Covered Soil  

Microsoft Academic Search

Results are presented of an experimental investigation to determine the relationship between radar backscatter coefficient ¿° and soil moisture for vegetation-covered soil. These results extend a previous report which showed the experimental relationship between ¿° and soil moisture for bare soil [1]. It is shown that the highest correlation between ¿° and soil moisture is 0.92 for the combined response

Fawwaz Ulaby; Gerald Bradley; Myron Dobson

1979-01-01

206

INFLUENCE OF COVER CROPS AND SOIL AMENDMENTS ON OKRA (ABELMOSCHUS ESCULENTUS L.) PRODUCTION AND SOIL NEMATODES  

Technology Transfer Automated Retrieval System (TEKTRAN)

A pot experiment to determine the effects of summer cover crops and soil amendments on okra yield and population densities of various soil nematode taxa was conducted in two consecutive growing seasons in a subtropical region. Two cover crops, sunn hemp (Crotalaria juncea) and sorghum sudangrass (So...

207

Investigation of Landfill Leachate Pollutant Attenuation by Soils.  

National Technical Information Service (NTIS)

In this laboratory study using 11 soils from 7 major orders in the U.S., the movement and retention of As, Be, Cd, CN, Cr, Cu, Hg, Ni, Pb, Se, V, and Zn when carried by municipal solid waste (MSW) leachate through soils was influenced by the individual pr...

W. H. Fuller

1978-01-01

208

Changes in soil characteristics during landfill leachate irrigation of Populus deltoides  

Microsoft Academic Search

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 (?0.033MPa) and at permanent wilting point (?1.5MPa) was determined with a pressure plate extractor to

Vesna Zupanc; Maja Zupan?i? Justin

2010-01-01

209

The effect of using a geotextile in a monolithic (evapotranspiration) alternative landfill cover on the resulting water balance.  

PubMed

This paper examines the potential effects of a geotextile layer used in a lysimeter pan experiment conducted in a monolithic (evapotranspiration) soil cover trial on its resulting water balance performance. The geotextile was added to the base of the lysimeter to serve as a plant root barrier in order to delineate the root zone depth. Both laboratory data and numerical modelling results indicated that the geotextile creates a capillary barrier under certain conditions and retains more water in the soil above the soil/geotextile interface than occurs without a geotextile. The numerical modelling results also suggested that the water balance of the soil cover could be affected by an increase in plant transpiration taking up this extra water retained above the soil/geotextile interface. This finding has a practical implication on the full-scale monolithic cover design, as the absence of the geotextile in the full-scale cover may affect the associated water balance and hence cover performance. Proper consideration is therefore required to assess the final monolithic cover water balance performance if its design is based on the lysimeter results. PMID:20541927

Sun, Jianlei; Yuen, Samuel T S; Fourie, Andy B

2010-06-11

210

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...

211

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...

212

Effects of willow stands on heavy metal concentrations and top soil properties of infrastructure spoil landfills and dredged sediment-derived sites  

Microsoft Academic Search

The effects of willow stand development on top soil properties of uncontaminated infrastructure spoil landfills (ISL) and contaminated dredged sediment landfills (DSL) were assessed. For the ISL, significant increases in Cd, Zn and organic C levels in the top soil (0–10 cm) were detected more than 20 years after disposal. The increases in Cd and Zn concentrations in the top soil were

Bart Vandecasteele; Paul Quataert; Gerrit Genouw; Suzanna Lettens; Filip M. G. Tack

2009-01-01

213

Rates of forest floor decomposition and soil forming processes as indicators of forest ecosystem functioning on a polluted dredged sediment landfill  

Microsoft Academic Search

Results of intensive monitoring of forest floor decomposition rates and soil forming processes after afforestation of a calcareous upland dredged sediment landfill with an oxidised surface soil are presented. Nutrient status of the sediment substrate favours tree growth and allows for afforestation and thus an integration in the landscape. Soil processes on the landfill resulted in small differences between the

Bart Vandecasteele; Bruno De Vos; Bart Muys; Filip M. G. Tack

2005-01-01

214

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

SciTech Connect

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

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

1996-02-01

215

Superfund Record of Decision (EPA Region 5): Lauer 1 Sanitary Landfill (Boundary Road), Menomonee Falls, WI., March 11, 1996.  

National Technical Information Service (NTIS)

The Boundary Road Landfill (formerly known as the Lauer 1 Landfill) is located in the northeastern portion of the Village of Menomonee Falls. Construction of a new multi-layer soil cover system over the landfill; installation of leachate extraction measur...

1996-01-01

216

[Investigation of polarization characteristics of soil surface with low vegetation cover and different soil moisture].  

PubMed

Compared with the spectral detection method, polarization detection could obtain more information of the target. For example, the polarization detection could be applied to interpret the refractive index and the surface roughness of the object, or retrieve the soil moisture, etc. Polarization detection provides a new approach to quantitative retrieval of soil moisture, and this is very important in agriculture, hydrology, meteorology and ecology. The polarization characteristics of soil surface with low vegetation cover,which is a example of mixed pixel in remote sensing, were researched with experiments, and the relationship between the polarization characteristics and soil moisture was also explored. The results showed that the polarization characteristics of soil surface with low vegetation cover are mainly determined by the area of bare soil, and are strongly relevant with the soil moisture. For the results of experiments in this paper, the IDOLP of soil surface with low vegetation cover increased with increasing soil moisture when the viewing angle of instrument was between 20 degree and 60 degree, while the incident angle of light source was fixed at 40 degree. This paper offered a new method to retrieve moisture content of soil with low vegetation cover. PMID:21284189

Zhang, Qiao; Sun, Xiao-bing; Hong, Jin

2010-11-01

217

The hydraulic conductivity of low permeability wet soils used as landfill lining and capping material: analysis of pressure infiltrometer measurements  

Microsoft Academic Search

The analysis of pressure infiltrometer measurements on low permeability wet soils used for landfill lining and capping material provided an estimate of values of field saturated hydraulic conductivity. Since the soil was almost saturated, steady-state flow through the ring was obtained soon after the start of a test without a significant initial unsteady absorption period. With the assumption that the

E. G. Youngs; P. B. Leeds-Harrison; D. E. Elrick

1995-01-01

218

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

PubMed

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

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

2008-10-05

219

Geoelectrical investigation of old\\/abandoned, covered landfill sites in urban areas: model development with a genetic diagnosis approach  

Microsoft Academic Search

Geoelectrical methods have an important, albeit difficult role to play in landfill investigations. In the present economic conditions, with the environmentally sensitive regime, adequate desk-study and model development are essential ingredients for a successful site investigation of landfills. This paper attempts to develop a genetic investigative model for old\\/abandoned landfill sites where the records of operations are not available. The

Maxwell A. Meju

2000-01-01

220

The effect of using a geotextile in a monolithic (evapotranspiration) alternative landfill cover on the resulting water balance  

Microsoft Academic Search

This paper examines the potential effects of a geotextile layer used in a lysimeter pan experiment conducted in a monolithic (evapotranspiration) soil cover trial on its resulting water balance performance. The geotextile was added to the base of the lysimeter to serve as a plant root barrier in order to delineate the root zone depth. Both laboratory data and numerical

Jianlei Sun; Samuel T. S. Yuen; Andy B. Fourie

2010-01-01

221

Final closure cover for a Hanford radioactive mixed waste disposal facility  

Microsoft Academic Search

This study provides a preliminary design for a RCRA mixed waste landfill final closure cover. The cover design was developed by a senior class design team from Seattle University. The design incorporates a layered design of indigenous soils and geosynthetics in a layered system to meet final closure cover requirements for a landfill as imposed by the Washington Administrative Code

Johnson

1996-01-01

222

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

SciTech Connect

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.

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

2004-05-12

223

A probabilistic model and software tool for evaluating the long-term performance of landfill covers  

Microsoft Academic Search

A probabilistic model and software tool has been developed to assist in the selection, design, and monitoring of long-term covers for contaminated subsurface sites. The software platform contains multiple modules that can be used to simulate relevant features, events, and processes that include water flux through the cover, source-term release, vadose-zone transport, saturated-zone transport, gas transport, and exposure pathways. The

Clifford K. Ho; Bill W. Arnold; John R. Cochran; Randal Y. Taira; Mitchell A. Pelton

2004-01-01

224

Landfill bioreactor design and operation  

SciTech Connect

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

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

1998-12-31

225

Soil phosphorus forms as quality indicators of soils under different vegetation covers.  

PubMed

The type of vegetation cover determines the physicochemical and biological properties of the soil over which they are developing. The objective of this study was to determine the effect of different vegetation covers on the forms of soil phosphorus, in order to know which of these forms can be used as a soil quality indicator. The experimental area was located on the acidic plateau at the North of Palencia (North Spain), where an area was selected vegetation covers very close to each other: pine (Pinus sylvestris), oak (Quercus pyrenaica), and three different shrub species (Arctostaphylos uva-ursi, Erica australis and Halimium alyssoides). The Ah horizon was sampled and pH, total organic C (C(org)), total N (N), cationic exchange capacity (CEC), sum of bases (S) and P forms by a sequential fractionation were analysed. Results showed that oak and A. uva-ursi improve the considered soil parameters (pH, C(org)/N ratio, CEC, and S) and provide soils of better quality. Inorganic soil P forms were influenced in greater extent by the vegetation cover than were P organic forms. Labile inorganic P forms could be used as indicators of soil quality. The organic P forms were less sensitive than inorganic ones to the indicated improvements. PMID:17307240

Turrión, María-Belén; López, Olga; Lafuente, Francisco; Mulas, Rafael; Ruipérez, César; Puyo, Alberto

2007-02-20

226

Geotechnical properties of paper mill sludges for use in landfill covers  

Microsoft Academic Search

This study investigates the geotechnical properties of seven paper mill sludges. Paper mill sludges have a high water content and a high degree of compressibility and behave like a highly organic soil. Consolidation tests reveal a large reduction in void ratio and high strain values that are expected due to the high compressibility. Triaxial shear-strength tests conducted on remolded and

Horace K. Moo-Young; Thomas F. Zimmie

1996-01-01

227

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

Microsoft Academic Search

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),

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

2006-01-01

228

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

Microsoft Academic Search

Cobble mulch and composted biosolids, greenwaste, and dairy manure were added to arid soil in an attempt to improve plant establishment and production, minimize erosion, increase evapotranspiration, and reduce leaching. Twenty-four plots (10 x 10 m) were established in a completely randomized block design (8 treatments, 3 plots per treatment). Treatments included (1) non-irrigated control, (2) irrigated control, (3) non-irrigated

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

2000-01-01

229

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

Microsoft Academic Search

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

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

2008-01-01

230

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

SciTech Connect

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.

Peace, Gerald (Jerry) 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

231

A simple model for predicting soil temperature in snow-covered and seasonally frozen soil: model description and testing  

Microsoft Academic Search

Microbial processes in soil are moisture, nutrient and temperature dependent and, consequently, accurate calculation of soil temperature is important for modelling nitrogen processes. Microbial activity in soil occurs even at sub-zero temperatures so that, in northern latitudes, a method to calculate soil temperature under snow cover and in frozen soils is required. This paper describes a new and simple model

K. Rankinen; T. Karvonen; D. Butterfield

2004-01-01

232

A test of hydrocarbon induced magnetic patterns in soils: Utilization of the sanitary landfill as a laboratory  

SciTech Connect

Magnetic susceptibility of soils has been studied in sanitary landfills, where upward fluxing methane has caused changes in magnetization of capping soils that were put into place, one, ten and twenty years before sampling. Susceptibilities increase progressively from uncontaminated control soils to samples with 20-year old caps, with the largest changes found below 40 cm depths. Authigenic minerals accumulate in landfill caps, with longer exposure to infiltration during reducing conditions producing higher magnetizations. Calcite and maghemite accumulate below 40 cm, iron and calcium having dissolved from above. Calcite accumulates during times of soil dessication, forming a harder to fluid transfer through caps that have distinctive zonations: Fe (II) accumulations above and Fe (III) highs below. Also found are well established CaCO{sub 3} barriers separating redox environments. Magnetic anomalies appear in caps exposed to high upward methane fluxes and periodic water infiltration, thus causing reducing environments favorable to magnetotactic bacterial growth. When microbial catalysis is high, Fe (II) is dissolved and transported deeper into the soil where it may re-precipitate as oxide or sulfide minerals phases that may or may not be magnetic. Precipitation of essentially non-magnetic Fe (II) phases during wet winters, followed by oxidation to magnetic phases during dry summers, has been previously observed in normal soils. Our study demonstrates that sanitary landfills are useful for studies of natural soil magnetism, and are effective model systems for the study of magnetic effects above areas of light-hydrocarbon flux, such as petroleum reservoirs.

Burkhart, B.; Ellwood, B.B. [Univ. of Texas, Arlington, TX (United States)

1995-06-01

233

Characterization of contaminated soil and groundwater surrounding an illegal landfill (S. Giuliano, Venice, Italy) by principal component analysis and kriging  

Microsoft Academic Search

The characterization of a hydrologically complex contaminated site bordering the lagoon of Venice (Italy) was undertaken by investigating soils and groundwaters affected by the chemical contaminants originated by the wastes dumped into an illegal landfill. Statistical tools such as principal components analysis and geostatistical techniques were applied to obtain the spatial distribution of chemical contaminants. Dissolved organic carbon (DOC), SO42?

Andrea Critto; Claudio Carlon; Antonio Marcomini

2003-01-01

234

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

SciTech Connect

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.

Albanna, Muna, E-mail: muna.albanna@gju.edu.j [Department of Civil Engineering, University of Ottawa, 161 Louis Pasteur St., Ottawa, Ontario, K1N 6N5 (Canada); Warith, Mostafa; Fernandes, Leta [Department of Civil Engineering, University of Ottawa, 161 Louis Pasteur St., Ottawa, Ontario, K1N 6N5 (Canada)

2010-02-15

235

Cultural Resources Review for Closure of the nonradioactive Dangerous Waste Landfill and Solid Waste Landfill in the 600 Area, Hanford Site, Benton County, Washington, HCRC# 2010-600-018R  

Microsoft Academic Search

The U.S. Department of Energy Richland Operations Office is proposing to close the Nonradioactive Dangerous Waste Landfill (NRDWL) and Solid Waste Landfill (SWL) located in the 600 Area of the Hanford Site. The closure of the NRDWL\\/SWL entails the construction of an evapotranspiration cover over the landfill. This cover would consist of a 3-foot (1-meter) engineered layer of fine-grained soil,

Jennifer L. Gutzeit; Ellen P. Kennedy; Bruce N. Bjornstad; Michael R. Sackschewsky; James J. Sharpe; Ranae DeMaris; M. Venno; James R. Christensen

2011-01-01

236

PhysicoChemical properties, heavy metals and their relations in cultivated landfill soils dumped with municipal solid wastes  

Microsoft Academic Search

Long-term fate and behaviour of heavy metals in soil, treated with composted-municipal solid wastes (MSW), are largely unknown. Accordingly, we investigated some physico-chemical properties, the relative availability (RA) of heavy metals and Cd\\/Zn ratio in soils of a century old cultivated landfill site dumped with Calcutta-MSW during monsoon, winter and summer seasons of 1999-2001. This was done to assess the

A Mitra; P Bhattacharyya; K Chakrabarti; DJ Chattopadhyay; A Chakraborty

2003-01-01

237

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

PubMed

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

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

2011-10-01

238

Laboratory and field testing for utilization of an excavated soil as landfill liner material.  

PubMed

This study investigates the feasibility of using a silty soil excavated in highway construction as landfill liner material. The tests were conducted both at laboratory and in situ scales, and the soil was tested in pure and lime treated forms. Different levels of compaction energy were used. For the field study, a test pad was constructed and in situ hydraulic conductivity experiments were conducted by sealed double ring infiltrometers (SDRI). Laboratory testing revealed that while lime treatment improved the shear strength, it resulted in higher hydraulic conductivity values compared to pure soil. It was observed that leachate permeation did not change the hydraulic conductivity of the pure and lime treated samples. Laboratory hydraulic conductivities were on the order of 10(-9) m/s and met the 1.0E-08 m/s criterion in the Turkish regulations, which is one order of magnitude higher than the value allowed in most developed countries. SDRI testing, which lasted for 6 mo, indicated that lime treatment increased the hydraulic conductivity of pure soil significantly in the field scale tests. In situ hydraulic conductivities were on the order of 1E-08 and 1E-07 m/s, and exceeded the allowable value in the Turkish regulations. Undisturbed samples collected from the test pad were not representative of field hydraulic conductivities. Contrary to laboratory findings, higher compaction efforts did not result in lower hydraulic conductivities in field scales. The study verified the importance of in situ hydraulic conductivity testing in compacted liners. PMID:16376067

Bozbey, Ilknur; Guler, Erol

2005-12-20

239

Hydrological Perturbations Drive Biogeochemical Processes in Experimental Soil Columns from the Norman Landfill Site  

NASA Astrophysics Data System (ADS)

Fate and transport of contaminants in saturated and unsaturated zones is governed by biogeochemical processes that are complex and non-linearly coupled to each other. A fundamental understanding of the interactions between transport and reaction processes is essential to better characterize contaminant movement in the subsurface. The objectives of this study are to: i) develop quantitative relationships between hydrological (initial and boundary conditions, hydraulic conductivity ratio, and soil layering), geochemical (mineralogy, surface area, redox potential, and organic matter) and microbiological factors (MPN) that alter the biogeochemical processes, and ii) characterize the effect of hydrologic perturbations on coupled processes occurring at the column scale. The perturbations correspond to rainfall intensity, duration of wet and dry conditions, and water chemistry (pH). Soils collected from two locations with significantly different geochemistry at the Norman landfill site are used in this study. Controlled flow experiments were conducted on: i) two homogeneous soil columns, ii) a layered soil column, iii) a soil column with embedded clay lenses, and iv) a soil column with embedded clay lenses and one central macropore. Experimental observations showed enhanced biogeochemical activity at the interface of the layered and lensed columns over the texturally homogeneous soil columns. Multivariate statistical analysis showed that the most important processes were microbial reduction of Fe(III) and SO42-, and oxidation of reduced products in the columns. Modeling results from HP1 indicate least redox activity in the homogeneous sand column while the structurally heterogeneous columns utilize oxygen and nitrate from recharge as well as iron sulfide minerals already present in the columns as electron acceptors. Furthermore, the interface of the layered and lensed soil columns acts as a hotspot of biogeochemical activity due to increased transport timescale as a result of reduced hydraulic conductivity of loam and clay in these columns. Although the coupled HP1 model was able to effectively capture redox dynamics in the experimental soil columns, findings suggest the need to incorporate: i) reduction in hydraulic conductivity due to the formation of iron sulfide precipitates, and ii) transport of aqueous iron sulfide clusters observed in all columns except homogeneous sand in such contaminant fate and transport models. Results indicate that textural differences across the layered, lensed, and macropore columns were directly responsible for redox gradient across these interfaces. Also, quantitative relationships observed between pH and total carbon, pe and redox couples, etc. are most significantly affected by wetting and drying cycles of the soil moisture regime for the different soil columns.

Arora, B.; Mohanty, B. P.; McGuire, J. T.

2010-12-01

240

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

SciTech Connect

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.

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

1992-12-01

241

The Influence of Soil Cover Heterogeneity on Water Movement within Water Balance Covers on Gold Mine Tailings 1  

Microsoft Academic Search

Cover system field trials are often constructed and monitored in order to develop calibrated soil-atmosphere numerical models. A model calibrated to measured cover system field trial performance (i.e. in situ conditions) can be used to: 1) help interpret monitoring data and identify key processes controlling performance, 2) validate measured net percolation, 3) predict cover system performance under long-term climate variability

P. Greg Meiers; S. Lee Barbour; Dennis Wilson

242

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

SciTech Connect

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.

Garten Jr., C.T.

2004-02-09

243

Fate of saline ions in a planted landfill site with leachate recirculation.  

PubMed

Recirculation of leachate on a covered landfill site planted with willows or other highly evapotranspirative woody plants is an inexpensive option for leachate management. In our study, a closed landfill leachate recirculation system was established on a rehabilitated municipal solid waste landfill site with planted landfill cover. The main objective of the study was to evaluate the sustainability of the system with regard to high hydraulic loads of the landfill leachate on the landfill cover and high concentrations of saline ions, especially potassium (K(+)), sodium (Na(+)) and chloride (Cl(-)), in leachate. The results of intensive monitoring, implemented during May 2004 and September 2007, including leachate, soil and plant samples, showed a high sustainability of the system regarding saline ions with the precipitation regime of the studied region. Saline ion concentrations in leachates varied between 132 and 2592mg Cl(-) L(-1), 69 and 1310mg Na(+) L(-1) and between 66 and 2156mg K(+) L(-1), with mean values of 1010, 632 and 686mg L(-1), respectively. Soil salinity, measured as soil electrical conductivity (EC), remained between 0.17 and 0.38mS cm(-1) at a depth between 0 and 90cm. An average annual precipitation of 1000mm provided sufficient leaching of saline ions, loaded by irrigation with landfill leachate, from the soil of the landfill cover and thus prevented possible salinity shocks to the planted willows. PMID:19796928

Loncnar, Mojca; Zupancic, Marija; Bukovec, Peter; Zupancic Justin, Maja

2009-09-30

244

Superfund record of decision amendment (EPA Region 4): Hercules 009 Landfill, Brunswick, GA, August 14, 1998  

SciTech Connect

This memorandum serves to present the Hercules 009 Landfill Superfund Site Explanation of Significant Difference (ESD) for concurrence. The Record of Decision (ROD) was signed on March 25, 1993 (PB94-964070). The ESD amends the ROD by changing the type of cover to be placed on the treated landfill soils and sludges. The ESD also explains EPA`s justification for determining the appropriate treatment depth in the landfill cells.

NONE

1999-03-01

245

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

PubMed

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

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

2013-02-04

246

Simulation of Infiltration Into Organic-covered Permafrost Soils  

Microsoft Academic Search

Infiltration into frozen or unfrozen soils is critical in permafrost hydrology, controlling active layer soil water dynamics and influencing runoff. Quantifying the infiltration process in permafrost soils is made difficult by variable ground thawing and freezing and the layered soil profile that frequently has organic soils atop mineral horizons. Moreover, harsh environments impose technical and logistic difficulties in accurately monitoring

Y. Zhang; S. K. Carey; W. L. Quinton; J. R. Janowicz; G. N. Flerchinger

2008-01-01

247

Fungal growth and biomass development is boosted by plants in snow-covered soil.  

PubMed

Soil microbial communities follow distinct seasonal cycles which result in drastic changes in processes involving soil nutrient availability. The biomass of fungi has been reported to be highest during winter, but is fungal growth really occurring in frozen soil? And what is the effect of plant cover on biomass formation and on the composition of fungal communities? To answer these questions, we monitored microbial biomass N, ergosterol, and the amount of fungal hyphae during summer and winter in vegetated and unvegetated soils of an alpine primary successional habitat. The winter fungal communities were identified by rDNA ITS clone libraries. Winter soil temperatures ranged between -0.6°C and -0.1°C in snow-covered soil. We found distinct seasonal patterns for all biomass parameters, with highest biomass concentrations during winter in snow-covered soil. The presence of plant cover had a significant positive effect on the amount of biomass in the soil, but the type of plant cover (plant species) was not a significant factor. A mean hyphal ingrowth of 5.6 m g(-1) soil was detected in snow-covered soil during winter, thus clearly proving fungal growth during winter in snow-covered soil. Winter fungal communities had a typical species composition: saprobial fungi were dominating, among them many basidiomycete yeasts. Plant cover had no influence on the composition of winter fungal communities. PMID:22234510

Kuhnert, Regina; Oberkofler, Irmgard; Peintner, Ursula

2012-01-12

248

Minimum depth of soil cover above long-span soil-steel railway bridges  

NASA Astrophysics Data System (ADS)

Recently, soil-steel bridges have become more commonly used as railway-highway crossings because of their economical advantages and short construction period compared with traditional bridges. The currently developed formula for determining the minimum depth of covers by existing codes is typically based on vehicle loads and non-stiffened panels and takes into consideration the geometrical shape of the metal structure to avoid the failure of soil cover above a soil-steel bridge. The effects of spans larger than 8 m or more stiffened panels due to railway loads that maintain a safe railway track have not been accounted for in the minimum cover formulas and are the subject of this paper. For this study, two-dimensional finite element (FE) analyses of four low-profile arches and four box culverts with spans larger than 8 m were performed to develop new patterns for the minimum depth of soil cover by considering the serviceability criterion of the railway track. Using the least-squares method, new formulas were then developed for low-profile arches and box culverts and were compared with Canadian Highway Bridge Design Code formulas. Finally, a series of three-dimensional (3D) finite element FE analyses were carried out to control the out-of-plane buckling in the steel plates due to the 3D pattern of train loads. The results show that the out-of-plane bending does not control the buckling behavior of the steel plates, so the proposed equations for minimum depth of cover can be appropriately used for practical purposes.

Esmaeili, Morteza; Zakeri, Jabbar Ali; Abdulrazagh, Parisa Haji

2013-12-01

249

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...

250

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

NASA Astrophysics Data System (ADS)

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 class to over 5 mg C/m^2/hr in the graminoid-dominated class. These findings suggest that shifts in land cover vegetation types, especially soil and vegetation loss (e.g. from wind deflation), can alter landscape soil respiration. We relate soil respiration measurements to soil, vegetation, and permafrost characteristics to understand how ecosystem properties and processes vary at the landscape scale. A long-term goal of this research is to develop a spatially explicit model of soil organic matter, soil respiration, and temperature sensitivity of soil carbon dynamics for a western Greenland permafrost tundra ecosystems.

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

2011-12-01

251

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

PubMed

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

Cheng, C Y; Chu, L M

2011-02-23

252

The soil–air exchange characteristics of total gaseous mercury from a large-scale municipal landfill area  

Microsoft Academic Search

The cycle of mercury (Hg) from a gigantic landfill area (area ?2.72km2) was investigated by conducting micrometeorological measurements of its exchange rates across soil–air boundary during the spring season of 2000. Based on this field campaign, we attempted to provide various insights into the Hg exchange processes, especially with respect to the decoupling of the mixed signatures of complex source

Ki-Hyun Kim; Min-Young Kim; Gangwoong Lee

2001-01-01

253

Selecting the ideal landfill site  

Microsoft Academic Search

The number of active landfills has decreased by nearly 3000 since 1984 as sites have run out of space and cannot be upgraded to meet tough new environmental requirements. How is the ideal landfill site defined This paper discusses the numerous considerations which would categorize an ideal landfill site. These include deep soils with low hydraulic conductivity; abundant workable soils

1989-01-01

254

Effects of long-term phosphorus fertilization and winter cover cropping on soil phosphorus transformations in less weathered soil  

Microsoft Academic Search

Information concerning sources and sinks of available P in soil is needed to improve soil P management and protect water quality. This study, conducted from 1989 to 1998 on a Sultan silt loam soil (Aquantic Xerochrept), determined the annual P removal rate by corn ( Zea mays L.) and P transformation as affected by P rate and winter cover cropping.

S. Kuo; B. Huang; R. Bembenek

2005-01-01

255

Modeling soil depth from topographic and land cover attributes  

Microsoft Academic Search

Soil depth is an important input parameter in hydrological and ecological modeling. Presently, the soil depth data available in national soil databases (STATSGO and SSURGO) from the Natural Resources Conservation Service are provided as averages within generalized land units (map units). Spatial uncertainty within these units limits their applicability for distributed modeling in complex terrain. This work reports statistical models

Teklu K. Tesfa; David G. Tarboton; David G. Chandler; James P. McNamara

2009-01-01

256

Ruminant Grazing of Cover Crops: Effects on Soil Properties and Agricultural Production  

ERIC Educational Resources Information Center

|Integrating livestock into a cropping system by allowing ruminant animals to graze cover crops may yield economic and environmental benefits. The effects of grazing on soil physical properties, soil organic matter, nitrogen cycling and agricultural production are presented in this literature review. The review found that grazing cover crops…

Poffenbarger, Hanna

2010-01-01

257

Effects of Ground Cover and Leaf Area on the Spectral Reflectance of Vegetation-Soil Target.  

National Technical Information Service (NTIS)

The relations between spectral reflectance, percent ground cover, and leaf area index (LAI) for vegetation-soil targets were evaluated for green vegetation against either a light-toned sand and a dark-toned organic loam soil. The percent ground cover and ...

M. B. Satterwhite P. Henley

1982-01-01

258

Influence of periglacial cover beds on in situ-produced cosmogenic 10Be in soil sections  

Microsoft Academic Search

Cover beds, widespread on hillslopes of temperate climate zones, represent layers of allochthonous material laterally transported by periglacial processes during the Late Pleistocene. Two soil sections comprised of cover beds from the Bavarian Forest, SE Germany, have been analysed for in situ-produced cosmogenic 10Be. Major changes in the nuclide concentration agree well with soil section boundaries defined by field observations

M. Schaller; F von Blanckenburg; H Veit; P. W Kubik

2003-01-01

259

COMPARISON OF NITROGEN MINERALIZATION FOLLOWING US AND BRAZILIAN COVER CROPS FOR A SOUTHERN PIEDMONT SOIL  

Technology Transfer Automated Retrieval System (TEKTRAN)

Winter cover crops are essential in conservation tillage systems to protect soils from erosion and for improving soil productivity. Black oat (Avena strigosa Schreb) and oilseed radish (Raphanus sativus L.) could be useful cover crops in the Southeastern USA but successful adoption requires underst...

260

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

NASA Astrophysics Data System (ADS)

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 ?·m. The second layer (Holocene-Q3) of semi-permeable silty and sandy clay cap (true resistivities 29 ~ 51 ?·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.

Khalil, Mohamed H.

2012-11-01

261

Development of a coupled reactor model for prediction of organic contaminant fate in landfills.  

PubMed

Models describing the behavior of organic chemicals in landfills can be useful to predict their fate and transport and also to generate input data for estimates of exposure and risk. The landfill coupled-reactor (LFCR) model developed in this work simulates a landfill as a series of fully mixed reactors, each representing a daily volume of waste. The LFCR model is a numerical model allowing time-variable input parameters such as gas generation, and cover type and thickness. The model was applied to three volatile organic chemicals (acetone, toluene, benzene) as well as naphthalene and the chemical warfare agent sarin under three landfill conditions (conventional, arid, bioreactor). Sarin was rapidly hydrolyzed, whereas naphthalene was largely associated with the landfill solid phase in all scenarios. Although similar biodegradation rates were used for acetone and toluene, toluene was more persistent in the landfill due to its hydrophobicity. The cover soil moisture content had a significant impact on gaseous diffusive losses. PMID:18939584

Lowry, Michael I; Bartelt-Hunt, Shannon L; Beaulieu, Stephen M; Barlaz, Morton A

2008-10-01

262

A statistical model for landfill surface emissions.  

PubMed

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

Héroux, Martin; Guy, Christophe; Millette, Denis

2010-02-01

263

The consequences of land-cover changes on soil erosion distribution in Slovakia  

Microsoft Academic Search

Soil erosion is a complex process determined by mutual interaction of numerous factors. The aim of erosion research at regional scales is a general evaluation of the landscape susceptibility to soil erosion by water, taking into account the main factors influencing this process. One of the key factors influencing the susceptibility of a region to soil erosion is land cover.

Tomás Cebecauer; Jaroslav Hofierka

2008-01-01

264

Are the closed landfills recovered habitats for small rodents? A case study in a riparian site, Buenos Aires, Argentina  

Microsoft Academic Search

The establishment of landfills in urban areas leads to extensive disturbances. Their development after landfill closure depends\\u000a on the characteristics of the soil cover, the surrounding communities and the dispersal of plants and animals. This study\\u000a was carried out in a landfill closed in 2004, surrounded by an urban area, freshwater marshes and a riparian forest. The aim\\u000a of this

María Florencia Carballido; Pablo Arístide; María Busch; Emilio A. Cittadino; Isabel E. Gómez Villafañe

265

Decline of Citrus due to presence of landfill gases in the soil  

Microsoft Academic Search

Over a period of years, the decline of citrus has been noted near sites located on or near landfill areas where aerobic or anaerobic decomposition is taking place. The symptoms of these declines in vigor are: growth reduction, leaf abscission, wilting, dieback, and eventual death of the tree. Similar declines have occurred in peach (Prunus persica Batsch.) orchards near landfills

Michael G. Bausher

1991-01-01

266

Analysis of soil organic carbon and vegetation cover trends along the Botswana Kalahari Transect  

Microsoft Academic Search

Determination of trends in soil organic carbon (SOC) and vegetation cover along savanna ecosystem moisture gradients is critical to the understanding of ecosystem functioning and global change. Field results from 57 sites along the Botswana Kalahari Transect (BKT) showed general increases in both SOC and vegetation cover components along the temperature\\/moisture gradient. However, details in both SOC and woody cover

Susan Ringrose; Wilma Matheson; Cornelis Vanderpost

1998-01-01

267

Water regime of soils under the different vegetative cover, the Giant Mountains, Czech Republic  

Microsoft Academic Search

Several monitored plots, located in the Giant Mountains in different positions (valley, slope), are covered by different vegetation (dwarf pine forest, spruce forest, meadow). Soil moisture properties in relation to vegetative cover (dwarf pine versus grassland stands) were studied from the year 2000 to 2006. The main goal was to analyse chosen rainfall-runoff periods with respect to diferent vegetative cover.

I. J. Dvorak; M. Tesar; J. Dohnal

2009-01-01

268

Estimate of methane emissions from US landfills. Final report, December 1992-January 1994  

SciTech Connect

The report describes the development of a statistical regression model used for estimating methane (CH4) emissions, which relates landfill gas (LFG) flow rates to waste-in-place data from 105 landfills with LFG recovery projects. The model has three linear segments, each of which applies to a distinct landfill size class. Assumptions were required to account for the recovery efficiency of LFG projects and for the probable oxidation of CH4 in the top soil cover of the landfill. The report details uncertainties which limit the quality of the above estimates. The report concludes with a discussion of trends which will affect future LFG emissions, as well as LFG utilization.

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

1994-09-01

269

Influence of soil pH on the fractionation of Cr, Cu and Zn in solid phases from a landfill site  

Microsoft Academic Search

The spatial variability of soil pH for engineered Weathered Oxford Clay is described using 35 samples collected from the base of a new cell in an existing landfill. Soil pH variability influences the reactivity of Cr, Cu and Zn in the site. The reactivity of these metals as natural components was determined using a sequential extraction method. The total concentration

G. Muñoz-Meléndez; A. Korre; S. J. Parry

2000-01-01

270

Willow growth in response to nutrients and moisture on a clay landfill cap soil. I. Growth and biomass production.  

PubMed

The growth and biomass production by willow (Salix viminalis L.) was studied in lysimeters containing Oxford clay landfill cap soil with different amendments, bulk densities and watering regimes. Three years from planting, stem biomass in well-watered plants was least (0.28 kg plant(-1)) with high bulk density soil (1480 kg m(-3)) and no nutritional amendment but was increased 10-fold (2.53 kg plant(-1)) by reducing soil bulk density (1200 kg m3) and adding amendments. In comparison, on a sandy loam soil it was 6.23 kg plant(-1). There were similar differences in number of stems plant(-1), stem basal area plant(-1) and plant leaf area which can be attributed to low nitrogen and phosphorus levels in Oxford clay. Water stress reduced stem biomass production by 26-37% and caused higher root:stem ratios. These were also higher on Oxford clay than on the sandy loam. Successful biomass production from willow on Oxford clay landfill caps will therefore require nutritional amendment. PMID:16216728

Martin, Peter J; Stephens, William

2005-04-25

271

Importance of soil cover box area for the determination of N 2 O emissions from arable soils  

Microsoft Academic Search

Five soil cover box systems varying in area were used to measure the N2O emissions from four arable soils. The covered area of the systems ranged from 78 to 576000 cm2. The observed N2O emission rates were approximately log-normal distributed. The greatest influence of variation of N2O emission rates could be attributed to the factor sampling date\\/time.

Ernst-August Kaiser; Jean Charles Munch; Otto Heinemeyer

1996-01-01

272

Theoretical basis and practical significance of investigations into soil cover patterns  

NASA Astrophysics Data System (ADS)

Principles and methods of studying the soil cover pattern for the inventory, assessment, and rational use of the natural resource potential are outlined. It is suggested that the soil cover patterns should be studied for typified natural systems (territorial units). The latter are different from one another in the composition and pattern of the soil combinations. The typology and hierarchical grouping of soil combinations are developed, and their nomenclature is suggested. The methodology for assessing the soil cover heterogeneity on the basis of a monofactor scale of the degree of the soil contrasts and a modified evaluation of the soil cover compartmentalization with the application of an automated cartographic analysis is described. This procedure has made it possible to gain an integral holistic perception of the geosystems in Belarus. The application of a corresponding database developed in the ArcInfo format for creating maps with information on the morphometric, geomorphic, hypsometric, lithological, and other characteristics of geosystems is illustrated. Special surveys of the soil cover patterns in Belarus were performed on an area of 10000000 ha. Their results are taken into account upon planning the rational nature management.

Romanova, T. A.; Chervan', A. N.; Andreeva, V. L.

2011-03-01

273

Final closure cover for a Hanford radioactive mixed waste disposal facility  

SciTech Connect

This study provides a preliminary design for a RCRA mixed waste landfill final closure cover. The cover design was developed by a senior class design team from Seattle University. The design incorporates a layered design of indigenous soils and geosynthetics in a layered system to meet final closure cover requirements for a landfill as imposed by the Washington Administrative Code WAC-173-303 implementation of the Resource Conservation and Recovery Act.

Johnson, K.D.

1996-02-06

274

Effects of snow-cover on annual and seasonal soil respiration from a temperate mountain forest soil  

NASA Astrophysics Data System (ADS)

Climate change will alter the duration and magnitude of snow cover, especially in temperate areas at lower altitude, where wintertime air temperatures often fluctuate around freezing. A five years time series of consecutive soil respiration measurements was used to assess the effects of duration and magnitude of cold season snow-cover on annual and seasonal soil CO2 efflux. The temperature sensitivity of soil CO2 efflux during the cold season was assessed from seasonal data as well as from high frequency measurements during periods when air/soil temperatures showed high fluctuation. Substrate limitation as a potential driver of soil CO2 efflux during the cold season was tested by periodic amendment of sucrose followed by measurement and determination of the isotopic signature (13C) of the substrate induced soil respiration in the field. First results will be presented at the conference.

Schindlbacher, Andreas; Jandl, Robert; Schindlbacher, Sabine

2013-04-01

275

Pendimethalin Wash?Off from Cover Crop Residues and Degradation in a Loessial Soil  

Microsoft Academic Search

Tillage and cover crops affect soil biological, chemical and physical properties that control the fate of herbicides in soil. Effects of conventional tillage (CT) and no tillage (NT) and either native winter annual vegetation, hairy vetch (Vicia villosa) or wheat (Triticum aestivum) on degradation of pendimethalin [N?(1?ethylpropyl)?3,4?dimethyl?2,6?dinitrobenzenamine] were investigated. Effect of pendimethalin sorption on residues of these cover crops on

L. A. Gaston; D. J. Boquet; M. A. Bosch

2003-01-01

276

Molecular detection and direct enumeration of methanogenic Archaea and methanotrophic Bacteria in domestic solid waste landfill soils  

Microsoft Academic Search

Methane oxidizing and producing activities of cover soil (10, 30 cm depth) and burial waste (1, 3 m depth) were evaluated: top cover soil (10 cm) had the highest methane oxidizing activity, while 1 m depth buried waste showed the highest methane producing potential. All the sequences of the 1 m sample were found to be closely related to 16S rDNAs of mainly hydrogenotrophic methanogens

Ann-Cheng Chen; Kumiko Ueda; Yuji Sekiguchi; Akiyoshi Ohashi; Hideki Harada

2003-01-01

277

Linking N Cycling to Microbial Function Within Soil Microenvironments in Cover Crop Systems  

NASA Astrophysics Data System (ADS)

Cover crops have emerged as a crop management strategy to achieve agricultural sustainability and maintain environmental quality. Thus, fundamental knowledge of microbial-mediated C and N cycling is vital to understanding soil organic matter (SOM) dynamics in cover cropped agroecosystems. We investigated the effects of short-term cover crop-C input on N processing by microbial communities within SOM microenvironments and in bulk soil, across a gradient of organic to conventional crop management. We hypothesized that cover crop C and N inputs promote soil aggregation, which increases the abundance of ammonia oxidizing bacteria (AOB) and stimulates greater microbial cycling of N within soil microenvironments, thereby leading to potential increases in N stabilization coupled with decreases in N loss. Our hypothesis was tested on the long-term organic, low-input, and conventional maize-tomato rotations at the Center for Integrated Farming Systems experiment (Davis, CA). We collected soil samples (0-15cm) across the cover crop and subsequent maize growing seasons and then isolated three SOM fractions soil: coarse particulate organic matter (cPOM; >250um), microaggregates (53-250um), and silt-and-clay (<53um). Total C and N were measured on both bulk soil and SOM fractions. Real-time polymerase chain reaction (PCR) using primers for the functional genes, amoA and nosZ, were employed to quantify AOB and denitrifier population sizes, respectively. We also measured gross ammonification and nitrification rates in short-term 15N-incubations of the bulk soil to link cover crop induced N cycling to N-transforming bacteria. Total soil C and N concentrations and soil aggregation were higher in the organic than conventional and low-input systems. The amoA and no Z copy numbers g-1 dry soil were highest in the microaggregate fraction and similar between the cPOM and silt-and-clay fractions, among all cropping treatments. Abundances of AOB and denitrifiers were lower in bulk soil from the conventional and low- input than organic system. Our study indicates that long-term, annual cover crop inputs to the organic system lead to greater aggregation and development of microaggregate structures. Consequently, the abundance of nitrifiers and denitrifiers as well as the rates of ammonification and nitrification are augmented in the organic system compared to the conventional, which does not receive a cover crop, and the low-input system, which receives cover crops only in alternate years. These results shed light on the specific mechanisms governing short-term N stabilization versus losses under long-term crop management.

Kong, A. Y.; Scow, K. M.; Hristova, K.; Six, J.

2007-12-01

278

Controls of biological soil crust cover and composition shift with succession in sagebrush shrub-steppe  

USGS Publications Warehouse

Successional stage may determine strength and causal direction of interactions among abiotic and biotic factors; e.g., species that facilitate the establishment of other species may later compete with them. We evaluated multivariate hypotheses about abiotic and biotic factors shaping biological soil crusts (BSCs) in early and late successional stages. We surveyed vegetation and BSC in the shrub-steppe ecosystem of the Columbia Basin. We analyzed the relationships with bryophyte and lichen covers using structural equation models, and analyzed the relationships with BSC composition using Indicator Species Analysis and distance-based linear models. Cover, indicator species, and composition varied with successional stage. Increasing elevation and bryophyte cover had higher lichen cover early in succession; these relationships were negative in the later successional stage. Lichen cover did not appear to impede B. tectorum cover, but B. tectorum appeared to strongly negatively affect lichen cover in both stages. Biological soil crust composition varied with bunchgrass cover in the early successional stage, but with elevation and B. tectorum cover later in succession. Our findings support the hypotheses that as succession progresses, the strength and direction of certain community interactions shift, and B. tectorum leads to reductions in biological soil crust cover regardless of successional stage.

Dettweiler-Robinson, E.; Bakker, J. D.; Grace, J. B.

2013-01-01

279

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

SciTech Connect

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.

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

1996-02-01

280

Spatial variability of soil water content in the covered catchment at Gårdsjön, Sweden  

Microsoft Academic Search

The spatial variability of soil water content was investigated for a 6300 m2 covered catchment on the Swedish west coast. The catchment podzol soil is developed in a sandy - silty till with a mean depth of 43 cm and the dominant vegetation is Norway spruce. The acid precipitation is removed by a plastic roof and replaced with lake water

Lars Nyberg

1996-01-01

281

Tillage, Cover Crop, and Kill-Planting Date Effects on Corn Yield and Soil Nitrogen  

Microsoft Academic Search

ha2 1 (Sainju and Singh, 1997). In addition, hairy vetch can improve soil and water quality compared with bare Tillage and spring kill date may affect cover crop N accumulation fallow by reducing erosion; NO3 leaching during fall, and subsequent N release to the soil, thereby influencing corn (Zea mays L.) N uptake and yield. We examined the influence of

Upendra M. Sainju; Bharat P. Singh

2001-01-01

282

The change in soil cover on the exposed bed of the Aral Sea  

Microsoft Academic Search

Desiccation of the Aral Sea has led to the formation of new soil cover on the exposed seabed. Investigation of the newly formed dry land is very important since it is a source of dust storms and salts transferred to long distances. A soil map of the exposed seabed for 2000 has been produced on the basis of the map

G. Stulina; V. Sektimenko

2004-01-01

283

Hydraulic conductivity, residue cover and soil surface roughness under different tillage systems in semiarid conditions  

Microsoft Academic Search

The objective of this study was to investigate the effect of tillage and cropping system on near-saturated hydraulic conductivity, residue cover and surface roughness to improve soil management for moisture conservation under semiarid Mediterranean conditions. Three tillage systems were compared (subsoil tillage, minimum tillage and no-tillage) under three field situations (continuous crop, fallow and crop after fallow) on two soils

J. Lampurlanés; C. Cantero-Martínez

2006-01-01

284

The role of tephra covers on soil moisture conservation at Haleakala's crater (Maui, Hawai'i)  

Microsoft Academic Search

The influence of tephra covers on soil water was studied in Haleakala (Maui, Hawai'i) during two summers; eight sites with tephra layers and silverswords (Argyroxiphium sandwicense DC.) were sampled at 2415–2755 m. At each site, eight paired-sample sets were obtained in bare soils and under adjacent tephra, at three depths. Tephra were sharply separated from underlying soils and showed prominent vertical

Francisco L. Pérez

2009-01-01

285

Effect of Pinyon–Juniper Tree Cover on the Soil Seed Bank  

Microsoft Academic Search

As pinyon-juniper (specifically, Pinus monophylla and Juniperus osteosperma) woodlands in the western United States increase in distribution and density, understory growth declines and the occurrence of crown fires increases, leaving mountainsides open to both soil erosion and invasion by exotic species. We examined if the loss in understory cover that occurred with increasing tree cover was reflected in the density

Elizabeth A. Allen; Robert S. Nowak

2008-01-01

286

Modeling Soil Depth Based Upon Topographic and Land Cover Attributes to Improve Models of Hydrological Response  

NASA Astrophysics Data System (ADS)

Soil depth is an important input parameter in hydrological modeling. Presently, the soil depth data available in national soil databases (STATSGO, SSURGO) is provided as averages within generalized map units. Spatial uncertainty within these units limits their applicability for distributed hydrological modeling in complex terrain. Statistical models were developed for prediction of soil depth in a semiarid mountainous watershed based upon topographic and land cover attributes. Soil depth was surveyed by driving a rod into the ground until refusal at 819 calibration and 130 independent testing locations selected to represent the topographic and land cover variation in Dry Creek Experimental Watershed, Boise, Idaho. Topographic attributes derived from a Digital Elevation Model (DEM) and Land cover attributes derived from remote sensing were used in Generalized Additive and Random Forest models to predict soil depth over the watershed. The models were able to explain about 50% of the soil depth spatial variation with a significant part of this capability due to new DEM derived topographic variables. The soil depths obtained from these models are being used as input to a spatially distributed hydrological model to evaluate the sensitivity of hydrological response and potential for improvement in hydrological model estimates due to better soil depth information.

Tesfa, T. K.; Tarboton, D. G.; Chandler, D. G.; McNamara, J. P.

2008-12-01

287

The litter cover of citrus leaves control soil and water losses in chemically managed orchards  

NASA Astrophysics Data System (ADS)

Soil erosion in chemically managed orchards results in bare soil due to the removal of the weeds and the lack of catch crops. Those conditions results in extremely high erosion rates in citrus orchards (Cerdà et al., 2011) such it has been found in other orchards in the Mediterranean where the soil degradation trigger a change in the soil water properties (Gómez et al., 1999). The Mediterranean climatic and human conditions contribute to very active soil water erosion (Ruiz Sinoga et al., 2010) where rilling and piping are found (Romero-Diaz, 2007). It is widely known that high erosion rates can trigger the soil degradation such it has been found in vineyards (Ramos and Martínez Casasnovas, 2006), Olive (García Orenes et al., 2010) and other crops, which is related to the land management and land use (García Ruiz, 2010). Within the chemically managed citrus orchards, the surface cover is usually bare due to the removal of the pruned branches (usually burned) and the use of herbicides every season. A thin and non-continuous litter layer of leaves from the citrus trees covers the soil surface, which sometimes are removed by the farmers to keep the soil clean. There is no information about the effect of the citrus leaves effects on soil and water losses. The objective of this paper is to quantify the effect of the leaves cover on the surface runoff and soil losses. Experiments were conducted by means of simulated rainfall at 55 mm h-1 during one hour in a small circular plot (0.25 m2) to quantify in the field the effect of different litter cover on soil erosion and water losses. An orchard of orange trees (Navel-lane-late, 10 year old, and planted at 6 x 5m with a 45 % cover) was selected in the Municipality of Montesa. Witin the 2 ha field 35 plots were selected with litter covers from 0 to 100 % cover. The runoff discharge was measured every minute and each 5 minutes a sample for runoff sediment concentration was collected. The sediment concentration was measured by dessication. All the measurements were conducted during the summer (August 2008). The results show that the litter cover control the erosion processes. The orange leaves lying on the floor can reduce the soil losses to negligible values when the cover is higher than 60 %. After 20 % of litter cover the soil losses are dramatically reduced to values lower than 50 % of the soil losses under bare soil conditions. The litter cover also reduces the runoff rates, but the reduction is in 50 % for 80 % litter cover. The 20 % litter cover results only in a small reduction in the runoff discharge. The research conducted demonstrate that the farmers should maintain the leaves on the floor (do not brush them as they use to do) to control the high erosion rates. This research study is being supported by the the research project CGL2008-02879/BTE

Cerdà, A.; Jurgensen, M. F.; González-Peñaloza, F. A.

2012-04-01

288

Quantifying the effect of oxidation on landfill methane emissions  

NASA Astrophysics Data System (ADS)

Field, laboratory, and computer modeling methods were utilized to quantitatively assess the capability of aerobic microorganisms to oxidize landfill-derived methane (CH4) in cover soils. The investigated municipal landfill, located in Nashua, New Hampshire, was operating without gas controls of any type at the time of sample collection. Soil samples from locations of CH4 flux to the atmosphere were returned to the laboratory and subjected to incubation experiments to quantify the response of oxidation in these soils to temperature, soil moisture, in situ CH4 mixing ratio, soil depth, and oxygen. The mathematical representations of the observed oxidation reponses were combined with measured and predicted soil characteristics in a computer model to predict the rate of CH4 oxidation in the soils at the locations of the measured fluxes described by Czepiel et al. [this issue]. The estimated whole landfill oxidation rate at the time of the flux measurements in October 1994 was 20%. Local air temperature and precipitation data were then used in conjunction with an existing soil climate model to estimate an annual whole landfill oxidation rate in 1994 of 10%.

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

1996-07-01

289

Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards  

NASA Astrophysics Data System (ADS)

When soil nitrate levels are low, plants suffer nitrogen (N) deficiency but when the levels are excessive, soil nitrates can pollute surface and subsurface waters. Strategies to reduce the nitrate pollution are necessary to reach a sustainable use of resources such as soil, water and plant. Buffer strips and cover crops can contribute to the management of soil nitrates, but little is known of their effectiveness in semiarid vineyards plantations. The research was carried out in the south coast of Sicily (Italy) to evaluate nitrate trends in a vineyard managed both conventionally and using two different cover crops (Triticum durum and Vicia sativa cover crop). A 10 m-wide buffer strip was seeded with Lolium perenne at the bottom of the vineyard. Soil nitrate was measured monthly and nitrate movement was monitored by application of a 15N tracer to a narrow strip between the bottom of vineyard and the buffer and non-buffer strips. Lolium perenne biomass yield in the buffer strips and its isotopic nitrogen content were monitored. Vicia sativa cover crop management contributed with an excess of nitrogen, and the soil management determined the nitrogen content at the buffer areas. A 6 m buffer strip reduced the nitrate by 42% with and by 46% with a 9 m buffer strip. Thanks to catch crops, farmers can manage the N content and its distribution into the soil over the year, can reduced fertilizer wastage and reduce N pollution of surface and groundwater.

Novara, A.; Gristina, L.; Guaitoli, F.; Santoro, A.; Cerdà, A.

2013-08-01

290

Surface energy balance model of transpiration from variable canopy cover and evaporation from residue-covered or bare soil systems: model evaluation  

Microsoft Academic Search

A surface energy balance model (SEB) was extended by Lagos et al. Irrig Sci 28:51–64 (2009) to estimate evapotranspiration (ET) from variable canopy cover and evaporation from residue-covered or bare soil systems.\\u000a The model estimates latent, sensible, and soil heat fluxes and provides a method to partition evapotranspiration into soil\\/residue\\u000a evaporation and plant transpiration. The objective of this work was

Luis Octavio Lagos; Derrel L. Martin; Shashi B. Verma; Suat Irmak; Ayse Irmak; Dean Eisenhauer; Andrew Suyker

291

VEGETATIVE COVERS FOR WASTE CONTAINMENT  

EPA Science Inventory

Disposal of municipal ahd hazardous waste in the United States is primarily accomplished by containment in lined and capped landfills. Evapotranspiration cover systems offer an alternative to conventional landfill cap systems. These covers work on completely different principles ...

292

Methane oxidation at a surface-sealed boreal landfill.  

PubMed

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

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

2009-03-04

293

Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards  

NASA Astrophysics Data System (ADS)

When soil nitrate levels are inadequate, plants suffer nitrogen deficiency but when the levels are excessive, nitrates (NO3-N) can pollute surface and subsurface waters. Strategies to reduce the nitrate pollution are necessary to reach a sustainable use of resources such as soil, water and plant. Buffer strips and cover crops can contribute to the management of soil nitrates, but little is known of their effectiveness in semiarid vineyards plantations. The experimental site, a 10 m wide and 80 m long area at the bottom of a vineyard was selected in Sicily. The soil between vine rows and upslope of the buffer strip (seeded with Lolium perenne) and non-buffer strips (control) was managed conventionally and with one of two cover crops (Triticum durum and Vicia sativa cover crop). Soil nitrate was measured monthly and nitrate movement was monitored by application of a 15N tracer to a narrow strip between the bottom of vineyard and the buffer and non-buffer strips. L. perenne biomass yield in the buffer strips and its isotopic nitrogen content were monitored. V. sativa cover crop management contribute with an excess of nitrogen, and the soil management determined the nitrogen content at the buffer areas. A 6 m buffer strip reduce the nitrate by 42% with and by 46% with a 9 m buffer strip.

Novara, A.; Gristina, L.; Guaitoli, F.; Santoro, A.; Cerdà, A.

2013-04-01

294

Paleo-shade: woody cover, stable isotopes, soil temperature, and soil organic matter in tropical ecosystems (Invited)  

NASA Astrophysics Data System (ADS)

The ?13C value of soil carbon is directly related to the fraction of C4 biomass in soils because of the difference in isotope discrimination between plants using the C3 (trees, shrubs, and herbs) and C4 (primarily tropical grasses) photosynthetic pathways. Almost all woody plants use the C3 photosynthetic pathway, and therefore the fraction of woody cover in tropical ecosystems has an important influence on the fraction of C4 biomass in soils. Surveys of tropical ecosystems from East Africa and Australia show that little C4 biomass is evident until woody cover fraction falls below 0.5. This is due to several factors, including the shading effect of woody cover and retention of soil moisture; these decrease the daily maximum ground surface temperature and decrease water stress. Thus, C3 photosynthesis is favored relative to C4 photosynthesis in well-shaded environments compared to nearby open environments. Between 0.0 and 0.5 fraction woody cover, the ?13C of soil organic matter is strongly correlated with the fraction of woody cover. However, as the woody cover approaches 0, in some semi-arid ecosystems a significant fraction of C3 herbaceous plants are present. Thus some “grasslands” may have a significant fraction of C3 herbaceous cover. Paleosols are an indicator of the fraction of C4 biomass because of their preserved ?13C values in organic matter and in pedogenic carbonate. This ?13C signal can be used as an indicator of “paleo-shade” or fraction of woody-cover in the geological record. ?47C values of paleosols for much of the past 4 Ma in the Turkana Basin in northern Kenya and the Awash Basin in Ethiopia indicate ecosystems similar to modern grasslands to woody grasslands (using the UNESCO classification for tropical ecosystems); these are commonly known as savannas. Thus some of the most important localities documenting hominin evolution show strong evidence for a savanna environment. This interpretation is supported by independent evidence from ‘carbonate clumped-isotope’ thermometry of Turkana Basin paleosol carbonates: this method reveals that deep (>50 cm) soil temperatures were ~30 - 35C during carbonate-forming intervals of the past 4 Ma, a temperature range significantly higher than temperatures of modern tropical forest soils, but similar to soil temperatures in open arid environments such as the present day Turkana Basin.

Cerling, T. E.; Andanje, S.; Kimutai, D.; Levin, N. E.; Mace, W. D.; Macharia, A. N.; Passey, B. H.; Remien, C.; Wynn, J. G.

2010-12-01

295

[Study on nutrient and salinity in soil covered with different vegetations in Shuangtaizi estuarine wetlands].  

PubMed

Nutrient elements and salinity in soil covered by different vegetations including Phragmites australis (Clay.) Trin., Typha orientalis Presl., Puccinellia distans Parl, and Suaeda salsa in Shuangtaizi estuarine wetlands were investigated to study their distribution characteristics and to reveal the nutrient element variation during the vegetation succession processes. Results indicated that total potassium, total phosphorus and salinity were different significantly in soil between different plant communities while available phosphorus, total nitrogen, available nitrogen, available potassium, total sulfur, iron and soil organic carbon were different insignificantly. Correlation analysis suggested that soil organic carbon were related significantly to total nitrogen, available phosphorus, available potassium, which implied that decomposition of plant litter might be the mail source of soil nitrogen and available nutrient. Salinity was significantly related to total phosphorus and iron in soil. In Shuangtaizi estuarine wetland soil, ratios of carbon to nitrogen (R(C/N)) was in the range of 12.21-26.33 and the average value was 18.21, which was higher than 12.0. It indicated that soil organic carbon in Shuangtaizi estuarine mainly came from land but not ocean and plants contributed the most of soil organic matters. There was no significant difference in R(C/N) between soil from the four plant communities (F = 1.890, p = 0.151). R(C/N) was related significantly to sol salinity (r = 0.346 3, p = 0.035 8) and was increasing with soil salinity. PMID:22165232

Song, Xiao-Lin; Lü, Xian-Guo; Zhang, Zhong-Sheng; Chen, Zhi-Ke; Liu, Zheng-Mao

2011-09-01

296

40 CFR 258.41 - Project XL Bioreactor Landfill Projects.  

Code of Federal Regulations, 2010 CFR

...of the waste; (xiv) Data on landfill settlement; (xv) Any information on the performance of the landfill cover; and (xvi) Observations...on the physical stability of the landfill. (6) This section will...

2003-07-01

297

40 CFR 258.41 - Project XL Bioreactor Landfill Projects.  

Code of Federal Regulations, 2010 CFR

...of the waste; (xiv) Data on landfill settlement; (xv) Any information on the performance of the landfill cover; and (xvi) Observations...on the physical stability of the landfill. (6) This section will...

2005-07-01

298

40 CFR 258.41 - Project XL Bioreactor Landfill Projects.  

Code of Federal Regulations, 2010 CFR

...of the waste; (xiv) Data on landfill settlement; (xv) Any information on the performance of the landfill cover; and (xvi) Observations...on the physical stability of the landfill. (6) This section will...

2004-07-01

299

Factors affecting water balance and percolate production for a landfill in operation.  

PubMed

Percolate production and precipitation data for a full-scale landfill in operation measured over a 13-year period were used to evaluate the impact and importance of the hydrological conditions of landfill sections on the percolate production rates. Both active (open) and closed landfill sections were included in the evaluation. A simple top cover model requiring a minimum of input data was used to simulate the percolate production as a function of precipitation and landfill section hydrology. The results showed that changes over time in the hydrology of individual landfill sections (such as section closure or plantation of trees on top of closed sections) can change total landfill percolate production by more than 100%; thus, percolate production at an active landfill can be very different from percolate production at the same landfill after closure. Furthermore, plantation of willow on top of closed sections can increase the evapotranspiration rate thereby reducing percolate production rates by up to 47% compared to a grass cover. This process, however, depends upon the availability of water in the top layer, and so the evaporation rate will be less than optimal during the summer where soil-water contents in the top cover are low. PMID:15751398

Poulsen, Tjalfe G; Møoldrup, Per

2005-02-01

300

Cover crops alter phosphorus soil fractions and organic matter accumulation in a Peruvian cacao agroforestry system  

Microsoft Academic Search

In many tropical soils, excessive weathering of primary minerals confounded by intense agricultural production has resulted\\u000a in the depletion of organic matter and plant available forms of phosphorus (P). Long-term growth of cover crops in tropical\\u000a agroforestry systems have been shown to influence nutrient cycling, and soil organic matter pools. The objective of this experiment\\u000a was to assess the affect

Hollie Hall; Yuncong Li; Nicholas Comerford; Enrique Arévalo Gardini; Luis Zuniga Cernades; Virupax Baligar; Hugh Popenoe

2010-01-01

301

Effective tools for Managing odours from landfill facilities in Ireland  

Microsoft Academic Search

Waste management facilities and especially landfill sites produce odours. Like the majority of industries, the operation of landfills, is faced with the issue of preventing odours causing impact to the public at large. Design, operational and management techniques can reduce the impact of odours from landfills. Containment of landfill gas through optimising landfill cover, gas collection systems and management techniques

J. W. Case; B. A. Sheridan; M. Henry

302

Soils and the soil cover of the arkaim reserve (Steppe Zone of the Trans-Ural Region)  

NASA Astrophysics Data System (ADS)

Soils of the Arkaim Reserve in the area around a unique settlement-fortress of the Bronze Age in Chelyabinsk oblast have been studied. These soils are generally typical of the entire Trans-Ural Plateau. The soil properties are characterized in detail on the basis of factual data on 170 soil pits and four soil catenas. The soil cover of the reserve is specified into six geomorphic groups: (a) denudational surfaces of the low mountains, (b) accumulative-denudational surfaces of the low mountains, (c) denudational-accumulative plain surfaces, (d) lacustrine-alluvial plain surfaces, (e) floodplain surfaces, and (f) slopes and bottoms of the local ravines and hollows. Chernozems occupy about 50% of the reserve; solonetzes and saline soils, 32%; meadow chernozems, 7%; and forest soils, 1%. The soils of the reserve are relatively thin; they have a distinct tonguing of the humus horizon and are often saline and solonetzic. The latter properties are inherited from the parent materials and are preserved in the soils for a long time under the conditions of a dry continental climate. The genetic features of the soils differ in dependence on the composition and age of the parent materials. With respect to the thickness of the soil profiles and the reserves of soil humus, the soils can be arranged into the following lithogenic sequence: the soils developed from the eluvium of igneous rocks-redeposited kaolin clay-montmorillonite-hydromica nonsaline and saline loams and clays. The content of Corg in the upper 20 cm varies from 2.5 to 5.6%, and the reserves of Corg in the layers of 0-0.5 and 0-1.0 m reach 57-265 and 234-375 t/ha, respectively. The soils of pastures subjected to overgrazing occupy two-thirds of the reserve. Their humus content is 10-16% higher in comparison with that in the analogous plowed soils. Another characteristic feature of the humus in the soils of the pastures is its enrichment in the labile fraction (28-40% of Corg).

Prikhod'ko, V. E.; Ivanov, I. V.; Manakhov, D. V.; Manakhova, E. V.

2012-08-01

303

Calculation set for design and optimization of vegetative soil covers Sandia National Laboratories, Albuquerque, New Mexico.  

SciTech Connect

This study demonstrates that containment of municipal and hazardous waste in arid and semiarid environments can be accomplished effectively without traditional, synthetic materials and complex, multi-layer systems. This research demonstrates that closure covers combining layers of natural soil, native plant species, and climatic conditions to form a sustainable, functioning ecosystem will meet the technical equivalency criteria prescribed by the U. S. Environmental Protection Agency. In this study, percolation through a natural analogue and an engineered cover is simulated using the one-dimensional, numerical code UNSAT-H. UNSAT-H is a Richards. equation-based model that simulates soil water infiltration, unsaturated flow, redistribution, evaporation, plant transpiration, and deep percolation. This study incorporates conservative, site-specific soil hydraulic and vegetation parameters. Historical meteorological data are used to simulate percolation through the natural analogue and an engineered cover, with and without vegetation. This study indicates that a 3-foot (ft) cover in arid and semiarid environments is the minimum design thickness necessary to meet the U. S. Environmental Protection Agency-prescribed technical equivalency criteria of 31.5 millimeters/year and 1 x 10{sup -7} centimeters/second for net annual percolation and average flux, respectively. Increasing cover thickness to 4 or 5 ft results in limited additional improvement in cover performance.

Peace, Gerald L.; Goering, Timothy James (GRAM, Inc., Albuquerque, NM)

2005-02-01

304

Willow growth in response to nutrients and moisture on a clay landfill cap soil. II: Water use.  

PubMed

Water use by willow (Salix viminalis L.) was studied in lysimeters containing clay landfill cap and sandy loam soils under different watering and amendment regimes. With plentiful water and amendments, seasonal ET increased annually and was highest in the sandy loam, increasing from 360 l plant(-1) in the establishment year to almost 1200 l plant(-1) in the third year. Seasonal ET was highly correlated with leaf area duration. Amendment of Oxford clay resulted in increases in plant leaf area, dry matter production and seasonal ET. Water stress reduced seasonal ET by 10-14% in the second year and 25-41% in the third. Water use efficiency was low for the un-amended clay treatment (1.4 g kg(-1)) but was similar in the amended clay (5.0 g kg(-1)) and sandy loam (4.9 g kg(-1)). This highlights the interdependence of water use and biomass production in willow. PMID:16216729

Martin, Peter J; Stephens, William

2005-04-25

305

Heavy metals, salts and organic residues in old solid urban waste landfills and surface waters in their discharge areas: determinants for restoring their impact.  

PubMed

This study was designed to determine the state of polluted soils in the main landfills of the Community of Madrid (central Spain), as part of a continuous assessment of the impacts of urban solid waste (USW) landfills that were capped with a layer of soil 20 years ago. Our analysis of this problem has been highly conditioned by the constant re-use of many of the USW landfills, since they have never been the target of any specific restoration plan. Our periodical analysis of cover soils and soils from discharge areas of the landfills indicates soil pollution has worsened over the years. Here, we examined heavy metal, salts, and organic compounds in soil and surface water samples taken from 15 landfills in the Madrid region. Impacts of the landfill soil covers on nematode and plant diversity were also evaluated. These analyses continue to reveal the presence of heavy metals (Zn, Cu, Cr, Ni, Pb, Cd) in soils, and salts (sulphates, chlorides and nitrates) in soils and surface waters. In addition, non-agricultural organic compounds, mainly aromatic and aliphatic hydrocarbons, often appeared in very high concentrations, and high levels of insecticides such as gamma-HCH (lindane) were also detected in soils. Around 50% of the water samples collected showed chemical demand of oxygen (CDO) values in excess of 150 mg/l. Traces of phenolic compounds were detected in some landfills, some of which exhibited high levels of 2-chlorophenol and pentachlorophenol. All these factors are conditioning both the revegetation of the landfill systems and the remediation of their slopes and terrestrial ecosystems arising in their discharge areas. This work updates the current situation and discusses risks for the health of the ecosystems, humans, domestic animals and wildlife living close to these landfills. PMID:21764209

Pastor, J; Hernández, A J

2011-07-20

306

Landfill mining: A critical review of two decades of research  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer We analyze two decades of landfill mining research regarding trends and topics. Black-Right-Pointing-Pointer So far landfill mining has mainly been used to solve waste management issues. Black-Right-Pointing-Pointer A new perspective on landfills as resource reservoirs is emerging. Black-Right-Pointing-Pointer The potential of resource extraction from landfills is significant. Black-Right-Pointing-Pointer We outline several key challenges for realization of resource extraction from landfills. - Abstract: Landfills have historically been seen as the ultimate solution for storing waste at minimum cost. It is now a well-known fact that such deposits have related implications such as long-term methane emissions, local pollution concerns, settling issues and limitations on urban development. Landfill mining has been suggested as a strategy to address such problems, and in principle means the excavation, processing, treatment and/or recycling of deposited materials. This study involves a literature review on landfill mining covering a meta-analysis of the main trends, objectives, topics and findings in 39 research papers published during the period 1988-2008. The results show that, so far, landfill mining has primarily been seen as a way to solve traditional management issues related to landfills such as lack of landfill space and local pollution concerns. Although most initiatives have involved some recovery of deposited resources, mainly cover soil and in some cases waste fuel, recycling efforts have often been largely secondary. Typically, simple soil excavation and screening equipment have therefore been applied, often demonstrating moderate performance in obtaining marketable recyclables. Several worldwide changes and recent research findings indicate the emergence of a new perspective on landfills as reservoirs for resource extraction. Although the potential of this approach appears significant, it is argued that facilitating implementation involves a number of research challenges in terms of technology innovation, clarifying the conditions for realization and developing standardized frameworks for evaluating economic and environmental performance from a systems perspective. In order to address these challenges, a combination of applied and theoretical research is required.

Krook, Joakim, E-mail: joakim.krook@liu.se [Department of Management and Engineering, Environmental Technology and Management, Linkoeping University, SE-581 83 Linkoeping (Sweden); Svensson, Niclas; Eklund, Mats [Department of Management and Engineering, Environmental Technology and Management, Linkoeping University, SE-581 83 Linkoeping (Sweden)

2012-03-15

307

Landfill CH{sub 4}: Rates, fates, and role in global carbon cycle  

SciTech Connect

Published estimates for worldwide landfill methane emissions range from 9 to 70 Tg yr{sup {minus}1}. Field and laboratory studies suggest that maximum methane yields from lanfilled refuse are about 0.06 to 0.09 m{sup 3} (dry Kg){sup {minus}1} refuse, depending on moisture content and other variables, such as organic loading, buffering capacity, and nutrients in landfill microevnironments. Methane yields may vary by more than an order of magnitude within a given site. Fates for landfill methane include (1) direct or delayed emission to the atmosphere through landfill cover materials or surface soils; (2) oxidation by methanotrophs in cover soils, with resulting emission of carbon dioxide; or (3) recovery of methane followed by combustion to produce carbon dioxide. The percent methane assigned to each pathway will vary among field sites and, for individual sites, through time. Nevertheless, a general framework for a landfill methane balance can be developed by consideration of landfill age, engineering and management practices, cover soil characteristics, and water balance. Direct measurements of landfill methane emissions are sparse, with rates between 10{sup {minus}6} and 10{sup {minus}8} g cm{sup {minus}2} s{sup {minus}1}; very high rates of 400 kg m{sup {minus}2} yr{sup {minus}1} have been measured at a semiarid unvegetated site. The proportion of landfill carbon that is ultimately converted to methane and carbon dioxide is problematical; the literature suggests that, at best, 25% to 40% of refuse carbon can be converted to biogas carbon. Cellulose contributes the major portion of the methane potential. Routine excavation of nondecomposed cellulosic materials after one or two decades of landfill burial suggests that uniformly high conversion rates are rarely attained at field sites.

Bogner, J.; Spokas, K.

1991-12-31

308

Landfill CH sub 4 : Rates, fates, and role in global carbon cycle  

SciTech Connect

Published estimates for worldwide landfill methane emissions range from 9 to 70 Tg yr{sup {minus}1}. Field and laboratory studies suggest that maximum methane yields from lanfilled refuse are about 0.06 to 0.09 m{sup 3} (dry Kg){sup {minus}1} refuse, depending on moisture content and other variables, such as organic loading, buffering capacity, and nutrients in landfill microevnironments. Methane yields may vary by more than an order of magnitude within a given site. Fates for landfill methane include (1) direct or delayed emission to the atmosphere through landfill cover materials or surface soils; (2) oxidation by methanotrophs in cover soils, with resulting emission of carbon dioxide; or (3) recovery of methane followed by combustion to produce carbon dioxide. The percent methane assigned to each pathway will vary among field sites and, for individual sites, through time. Nevertheless, a general framework for a landfill methane balance can be developed by consideration of landfill age, engineering and management practices, cover soil characteristics, and water balance. Direct measurements of landfill methane emissions are sparse, with rates between 10{sup {minus}6} and 10{sup {minus}8} g cm{sup {minus}2} s{sup {minus}1}; very high rates of 400 kg m{sup {minus}2} yr{sup {minus}1} have been measured at a semiarid unvegetated site. The proportion of landfill carbon that is ultimately converted to methane and carbon dioxide is problematical; the literature suggests that, at best, 25% to 40% of refuse carbon can be converted to biogas carbon. Cellulose contributes the major portion of the methane potential. Routine excavation of nondecomposed cellulosic materials after one or two decades of landfill burial suggests that uniformly high conversion rates are rarely attained at field sites.

Bogner, J.; Spokas, K.

1991-01-01

309

Biostabilization of landfill waste  

SciTech Connect

In November 1991, the city of Albany, N.Y., together with the principals of Landfill Service Corp. (Apalachin, N.Y.), proposed to demonstrate the successful practice of biostabilized solid waste placement in the newly constructed, double-composite-lined Interim Landfill located in the city of Albany. The small landfill covers just 12 acres and is immediately adjacent to residential neighbors. The benefits of this biostabilization practice include a dramatic improvement in the orderliness of waste placement, with significant reduction of windblown dust and litter. The process also reduces the presence of typical landfill vectors such as flies, crows, seagulls, and rodents. The physically and biologically uniform character of the stabilized waste mass can result in more uniform future landfill settlement and gas production properties. This can allow for more accurate prediction of post-closure conditions and reduction or elimination of remedial costs attendant to post-closure gross differential settlement.

Hansen, D.L. [Landfill Service Corp., Apalachin, NY (United States)

1995-06-01

310

Soil enzymatic activities in a hilly coffee plantation in lampung province, South Sumatra, Indonesia, under plant cover management  

Microsoft Academic Search

The effect of weed cover on the activities of soil enzymes (acid phosphatase, alkaline phosphatase, ?-glucosidase, and arylsulfatase) was evaluated in plots established in a coffee plantation field that was located in a hilly area in Lampung Province, South Sumatra, Indonesia. The plots were as follows: plot without cover weed (control plot), plot covered with Paspalum conjugatum, and plot covered

Abdul Kadir Salam; Afandi; Nanik Sriyani; Makoto Kimura

2001-01-01

311

TILLAGE, COVER CROP, AND NITROGEN FERTILIZER SOURCE EFFECTS ON SOIL CARBON AND NITROGEN SEQUESTRATION.  

Technology Transfer Automated Retrieval System (TEKTRAN)

The 10-yr effect of combinations of tillage (no-till, mulch till, and conventional till), cover crop (rye vs. none), and N fertilization source and rate (0 and 100 kg N ha-1 from NH4NO3 and 100 and 200 kg N ha-1 from poultry manure) was evaluated on crop residues and soil organic C (SOC) and organic...

312

Amendments and plant cover influence on trace element pools in a contaminated soil  

Microsoft Academic Search

A 30-month experiment was carried out in field containers to evaluate the potential of various amendments and\\/or a plant cover (Agrostis stolonifera L.) for reclamation of a soil contaminated with As, Cd, Cu, Pb and Zn. Five amended treatments with plant were established: leonardite (LEO), litter (LIT), municipal waste compost (MWC), biosolid compost (BC) and sugar beet lime (SL). Two

Alfredo Pérez-de-Mora; Fernando Madrid; Francisco Cabrera; Engracia Madejón

2007-01-01

313

Modeling response of soil erosion and runoff to changes in precipitation and cover  

Microsoft Academic Search

Global climate has changed over the past century. Precipitation amounts and intensities are increasing. In this study we investigated the response of seven soil erosion models to a few basic precipitation and vegetation related parameters using common data from one humid and one semi-arid watershed. Perturbations were made to inputs for rainfall intensities and amounts, and to ground surface cover

M. A. Nearing; V. Jetten; C. Baffaut; O. Cerdan; A. Couturier; M. Hernandez; Y. Le Bissonnais; M. H. Nichols; J. P. Nunes; C. S. Renschler; V. Souchère; K. van Oost

2005-01-01

314

Addition of cover crops enhances no-till potential for improving soil physical properties  

Technology Transfer Automated Retrieval System (TEKTRAN)

Interest in the use of cover crops (CC) is growing. Inclusion of CC may be a potential strategy to boost no-till performance by improving soil physical properties. To assess this potential, we utilized a wheat [Triticum aestivum (L.)]-grain sorghum [Sorghum bicolor (L.) Moench] rotation, four N rate...

315

Studies of soil gas, gas generation, and shallow microbial activity at Mallard North Landfill, Dupage County, Illinois  

Microsoft Academic Search

Three types of investigations at the Mallard North Landfill during the last five years have led to the development of useful field and laboratory techniques for better understanding gas generation, gas migration, and shallow microbial processes at any landfill. This paper summarizes the techniques with reference to representative results from Mallard North and discusses their general applicability to landfill site

J. E. Bogner; M. Vogt; R. M. Miller

1990-01-01

316

Fluxes of methane between landfills and the atmosphere: Natural and engineered controls  

SciTech Connect

Field measurement of landfill methane emissions indicates natural variability spanning more than 2 seven orders of magnitude, from approximately 0.0004 to more than 4000 g m{sub -2} day{sup -1}. This wide range reflects net emissions resulting from production (methanogenesis), consumption (methanotrophic oxidation), and gaseous transport processes. The determination of an {open_quotes}average{close_quotes} emission rate for a given field site requires sampling designs and statistical techniques which consider spatial and temporal variability. Moreover, particularly at sites with pumped gas recovery systems, it is possible for methanotrophic microorganisms in aerated cover soils to oxidize all of the methane from landfill sources below and, additionally, to oxidize methane diffusing into cover soils from atmospheric sources above. In such cases, a reversed soil gas concentration gradient is observed in shallow cover soils, indicating bidirectional diffusional transport to the depth of optimum methane oxidation. Rates of landfill methane oxidation from field and laboratory incubation studies range up to 166 g m{sup -2} day{sup -1} among the highest for any natural setting, providing an effective natural control on net emissions. Estimates of worldwide landfill methane emissions to the atmosphere have ranged from 9 to 70 Tg yr{sup -1}, differing mainly in assumed methane yields from estimated quantities of landfilled refuse. At highly controlled landfill sites in developed countries, landfill methane is often collected via vertical wells or horizontal collectors. Recovery of landfill methane through engineered systems can provide both environmental and energy benefits by mitigating subsurface migration, reducing surface emissions, and providing an alternative energy resource for industrial boiler use, on-site electrical generation, or upgrading to a substitute natural gas.

Bogner, J. [Argonne National Lab., IL (United States); Meadows, M. [ETSU, Harwell, Oxfordshire (United Kingdom); Czepiel, P. [Harvard Univ., Cambridge, MA (United States)

1997-08-01

317

Effects of landfill gas on subtropical woody plants  

NASA Astrophysics Data System (ADS)

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

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

1991-05-01

318

Environmental factors regulating winter CO2 flux in snow-covered boreal forest soil, interior Alaska  

NASA Astrophysics Data System (ADS)

Winter CO2 flux is an important element to assess when estimating the annual carbon budget on regional and global scales. However, winter observation frequency is limited due to the extreme cold weather in sub-Arctic and Arctic ecosystems. In this study, the continuous monitoring of winter CO2 flux in black spruce forest soil of interior Alaska was performed using NDIR CO2 sensors at 10, 20, and 30 cm above the soil surface during the snow-covered period (DOY 357 to 466) of 2006/2007. The atmospheric pressure was divided into four phases: >1000 hPa (HP: high pressure); 985soil. Atmospheric temperature, pressure, and soil temperature correlate at levels of 56, 25, and 31 % to winter CO2 flux, respectively, during the snow-covered period of 2006/2007, when snow depth experienced one of its lowest totals of the past 80 years. Atmospheric temperature and soil temperature at 5 cm depth, modulated by atmospheric pressure, were found to be significant factors in determining winter CO2 emission and fluctuation in snowpack. Regional/global process-based carbon cycle models should be reassessed to account for the effect of winter CO2 emissions, regulated by temperature and soil latent-heat flux, in the snow-covered soils of Arctic and sub-Arctic terrestrial ecosystems of the Northern Hemisphere.

Kim, Y.; Kodama, Y.

2012-01-01

319

Winter rye cover crop management influences on soil water, soil nitrate, and corn development  

Technology Transfer Automated Retrieval System (TEKTRAN)

A winter rye (Secale cereale L.) cover crop can be seeded after corn (Zea mays L.) silage to mitigate some of the environmental concerns associated with this cropping system. Rye can be managed as a cover crop by chemical termination or harvested as for forage. A field study was conducted in Morris,...

320

Characterization of an urban landfill soil by using physicochemical analysis and solid phase microextraction (SPME)-GC/MS.  

PubMed

We have aimed at characterizing top soil samples taken in-situ from five different locations of the unregulated dumping site in Eski?ehir/Turkey for a period of six months. The study is the first attempt in the city and in Turkey, regarding particularly the SPME (Solid Phase Microextraction Technique) analysis method utilized. A comprehensive research has been conducted to produce critical soil data to be used for indicating current risks as well as the urgency of rehabilitating the site and establishing a sanitary landfill in the site. Conventional physicochemical analytical methods and SPME technique were used to analyze the samples. Physicochemical analyses were performed for determining the pH, total dried matter, volatile matter, total nitrogen, phosphorus, macro elements and heavy metals. Meteorological data were also recorded for the same period. SPSS.10.0 statistical program was used to determine the correlation between meteorological data and physicochemical analysis results. Mean values were used in the correlation analyses. These data indicated that the air temperature and precipitation have significant effects on soil characteristics. SPME, coupled with GC/MS, was used to identify eighty six volatile and semi-volatile organic compounds contained in soil samples. The samples were extracted by headspace SPME with heating (DeltaHS-SPME). SPME analyses were conducted using a commercially available polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber having a film thickness of 65 microm (Supelco) as a capture medium. The experimentally optimized headspace sampling conditions were arranged (15 min. at 50 degrees C) before a 30 min. sampling period. PMID:17058004

Banar, Müfide; Ozkan, Aysun; Vardar, Ci?dem

2006-10-21

321

Molecular characterization of fungal communities in non-tilled, cover-cropped upland rice field soils.  

PubMed

This study aimed to characterize soil fungal communities in upland rice fields managed with tillage/non-tillage and winter cover-cropping (hairy vetch and cereal rye) practices, using PCR-based molecular methods. The study plots were maintained as upland fields for 5 years and the soils sampled in the second and fifth years were analyzed using T-RFLP (terminal restriction fragment length polymorphism) profiling and clone libraries with the internal transcribed spacer (ITS) region and domain 1 (D1) of the fungal large-subunit (fLSU) rRNA (D1(fLSU)) as the target DNA sequence. From the 2nd-year-sample, 372 cloned sequences of fungal ITS-D1(fLSU) were obtained and clustered into 80 nonredundant fungal OTUs (operational taxonomic units) in 4 fungal phyla. The T-RFLP profiling was performed with the 2nd- and 5th-year-samples and the major T-RFs (terminal restriction fragments) were identified using a theoretical fragment analysis of the ITS-D1(fLSU) clones. These molecular analyses showed that the fungal community was influenced more strongly by the cover-cropping than tillage practices. Moreover, the non-tilled, cover-cropped soil was characterized by a predominance of Cryptococcus sp. in the phylum Basidiomycota. We provided a genetic database of the fungal ITS-D1(fLSU)s in the differently managed soils of upland rice fields. PMID:21597240

Nishizawa, Tomoyasu; Zhaorigetu; Komatsuzaki, Masakazu; Sato, Yoshinori; Kaneko, Nobuhiro; Ohta, Hiroyuki

2010-01-01

322

The Effects of Snow Cover and Soil Moisture on Asian Dust: II. Emission Estimation by Lidar Data Assimilation  

Microsoft Academic Search

This paper is the second of a series that describes the effects of snow cover and soil moisture on Asian dust during spring. Whereas the first paper in this series discussed the importance of snow cover and soil moisture estimation, here, we focus on the correctness of the dust emission intensity results based on data assimilation under the assumption that

Tsuyoshi Thomas Sekiyama; Taichu Y. Tanaka; Takashi Maki; Masao Mikami

2011-01-01

323

Effects of soil fertilization and covering of the culture with plastic film on the provitamin A content of early lettuces  

Microsoft Academic Search

Different growing conditions of early lettuces were assayed. Some plots of lettuces were grown covered with a perforated plastic sheet, and other plots were not covered. The soil of some plots was fertilized with a usual N+P+K+S fertilizer used at a normal rate, and the soil of other plots with a fertilizer containing only nitrogen at a rate about 40

J. Rouchaud; C. Moons; J. A. Meyer; F. Benoit; N. Ceustermans; F. Linden

1984-01-01

324

The effect of surface cover and soil devastation on infiltration rate in steep forest plantations  

NASA Astrophysics Data System (ADS)

The Japanese cypress (Hinoki; Chamaecyparis obtusa) is a major commercial tree species in Japan, and without thinning of high-density stands, canopy closure prevents development of understory vegetation. Therefore there is a concern for overlandflow and sediment yield due to infiltration rate lowering. We developed a light-weight rainfall simulator based on the design of Meyer and Harmon (1979). A flat fan Veejet 80150 spraying nozzle (Spraying systems Co., USA) is mounted on the manifold at 2.13 m high from the plot surface. The nozzle oscillates so that the spray fan sweeps across the targeting 1 m x 1 m plot. The Veejet 80150 spraying nozzle produces large raindrops larger than 2 mm in diameter, and can simulate the high raindrop kinetic energy of natural throughfall. A targeted rainfall rate is 180 mm/h. About 30 sprinkling experiments have been conducted on 35-degree hillslopes with varying surface cover in 5 locations in Japan. We obtained the minimum infiltration rate of 14 mm/h where the surface cover is very little. The infiltration rates were plotted against the total understory vegetation and dry weight of total surface cover including litter. The infiltration rate increased with the increasing total surface cover, and generally higher regression coefficient was found for the case of the total surface cover. In some cases, high infiltration rates were obtained where surface cover is low. Two possible explanations can be made; 1) surface soil (especially fine particles) has been washed away, where soil is mostly composed of gravel and the percentage of fine fraction is low, or 2) because of long-term soil loss by raindrop detachment, remaining soil looks like "ghanging"h between exposed fine root networks of Japanese cypress, where soil bulk density is significantly lower than other site. Therefore the infiltration rate in the devastated Japanese cypress plantations is not only controlled by loss of surface vegetation by low light condition, but soil devastation through long-term erosion history would also control the infiltration rate and then geomorphic processes.

Onda, Y.; Hiraoka, M.; Kato, H.; Gomi, T.; Miyata, S.; Mizugaki, S.

2008-12-01

325

Mercury air-borne emissions from 5 municipal solid waste landfills in Guiyang and Wuhan, China  

NASA Astrophysics Data System (ADS)

A detailed study on atmospheric mercury emissions from municipal solid waste (MSW) landfills in China is necessary to understand mercury behavior in this source category, simply because China disposes of bulk MSW by landfilling and a large quantity of mercury enters into landfills. Between 2003 and 2006, mercury airborne emissions through different pathways, as well as mercury speciation in landfill gas (LFG) were measured at 5 MSW landfills in Guiyang and Wuhan, China. The results showed that mercury content in the substrate fundamentally affected the magnitude of mercury emissions, resulting in the highest emission rate (as high as 57 651 ng Hg m-2 h-1) at the working face and in un-covered waste areas, and the lowest measured at soil covers and vegetation areas (less than 20 ng Hg m-2 h-1). Meteorological parameters, especially solar radiation, influenced the diurnal pattern of mercury surface-air emissions. Total gaseous mercury (TGM) in LFG varied from 2.0 to 1406.0 ng m-3, monomethyl mercury (MMHg) and dimethyl mercury (DMHg) in LFG averaged at 1.93 and 9.21 ng m-3, and accounted for 0.51% and 1.79% of the TGM in the LFG, respectively. Total mercury emitted from the five landfills ranged from 17 to 3285 g yr-1, with the highest from the working face, then soil covering, and finally the vent pipes.

Li, Z. G.; Feng, X.; Li, P.; Liang, L.; Tang, S. L.; Wang, S. F.; Fu, X. W.; Qiu, G. L.; Shang, L. H.

2010-01-01

326

[Ecological effect of recirculated landfill leachate with different hydraulic loading on plant-soil system].  

PubMed

The ecological effect of irrigating recirculated leachate with different hydraulic loading on bermudagrass (Cynodon dactylon) and soil system was evaluated. The results show that leachate irrigation with hydraulic loading of 2.77-12.00 mm d(-1) leads to high chlorophyll content, low proline (Pro) content, as well as low malondialdehyde (MDA) and H2O2 content. Soil enzyme activities, respirations, microbial biomass and ratio of biomass carbon to organic carbon (Cmic/Corg) are rather higher. Among leachte irrigation group, leachate irrigation with hydraulic loading of 6.46-10.15 mm x d(-1) leads to declined proline, increased chlorophyll content, low POD activity and low content of MDA and H2O2. Soil bio-activity related parameters, such as soil enzyme activities, respirations, microbial biomass and Cmic/Corg are all enhanced at 6.46-10.15 mm x d(-1) of hydraulic loading. However, when hydraulic loading increases to 12.00 mm x d(-1) or declines to 2.77-4.16 mm x d(-1), the stress of irrigation on bermudagrass is aggravated, and soil bioactivity declines. The results reveal that leachate irrigation could alleviate the stress of environment on bermudagrass and improve the bio-activity of soil. The positive effect of leachate irrigation on the plant-soil system might be contributed to changes of soil water and physico-chemical property after leachate irrigated to the soil. The experimental results suggest that leachate irrigation could benefit plant-soil system, especially when controlled at suitable hydraulic loading. PMID:16850839

Wang, Ru-yi; He, Pin-jing; Shao, Li-ming; Yuan, Li; Li, Guo-jian

2006-05-01

327

Use of Moisture Profiles and Lysimetry to Assess Evapotranspirative Cover Performance  

Microsoft Academic Search

The performance of evapotranspirative landfill covers, often used in municipal and hazardous waste disposal applications, is quantified in this study using basal percolation and soil moisture content data obtained over six years through a comprehensive field monitoring program. Specifically, this paper presents applications of soil moisture profiles and numerical modeling to verify percolation measured by a lysimeter. Inconsistencies between the

John McCartney; Jorge G. Zornberg

328

Black oat cover crop management effects on soil temperature and biological properties on a Mollisol in Texas, USA  

Microsoft Academic Search

Management of a black oat (Avena strigosa [Schreb.]) cover crop by mowing method (none, flail mowing, or sickle bar mowing) affected soil micro environmental conditions and soil microbial and chemical properties. Soil temperatures at depths of 0, 5, 10 and 20 cm were highest in flail mowed treatment plots (up to near 45 °C at 5 cm depth), followed by sickle bar mowed

L. M. Zibilske; D. J. Makus

2009-01-01

329

[Succession-driven transformation of plant and soil cover on solifluction sites in the permafrost zone of central Evenkia].  

PubMed

The impact of solifluction (soil-sliding) on soil and vegetation cover as well as their restoration during the period after the disturbance was analyzed in the continuous permafrost region of Central Siberia (Central Evenkia). The role of vegetation invading after a disturbance is demonstrated for accumulation of biogenic elements and soil development. PMID:20238469

Prokushkin, S G; Bugaenko, T N; Prokushkin, A S; Shkikunov, V G

330

Applications of remote sensing and GIS in surface hydrology: Snow cover, soil moisture and precipitation  

NASA Astrophysics Data System (ADS)

Studies on surface hydrology can generally be classified into two categories, observation for different components of surface water, and modeling their dynamic movements. This study only focuses on observation part of surface water components: snow cover, soil moisture, and precipitation. Moreover, instead of discussion on the detailed algorithm and instrument technique behind each component, this dissertation pours efforts on analysis of the standard remotely sensed products and their applications under different settings. First in Chapter 2, validation of MODIS Terra 8-day maximum snow cover composite (MOD10A2) in the Northern Xinjiang, China, from 2000-2006, shows that the 8-day MODIS/Terra product has high agreements with in situ measurements as the in situ snow depth is larger or equal to 4 cm, while the agreement is low for the patchy snow as the in situ snow depth less than 4 cm. According to the in situ observation, this chapter develops an empirical algorithm to separate the cloud-covered pixels into snow and no snow. Continued long-term production of MODIS-type snow cover product is critical to assess water resources of the study area, as well as other larger scale global environment monitoring. Terra and Aqua satellites carry the same MODIS instrument and provide two parallel MODIS daily snow cover products at different time (local time 10:30 am and 1:30 pm, respectively). Chapter 3 develops an algorithm and automated scripts to combine the daily MODIS Terra (MOD10A1) and Aqua (MYD10A1) snow cover products, and to automatically generate multi-day Terra-Aqua snow cover image composites, with flexible starting and ending dates and a user-defined cloud cover threshold. Chapter 4 systematically compares the difference between MODIS Terra and Aqua snow cover products within a hydrologic year of 2003-2004, validates the MODIS Terra and Aqua snow cover products using in situ measurements in Northern Xinjiang, and compares the accuracy among the standard MODIS Terra and Aqua snow cover products, and the new combined daily and multi-day composite from both MODIS Terra and Aqua daily products. In Chapter 5, utilizing the new cloud-low multi-day composite of MODIS Terra and Aqua snow cover products, several new methods are developed to study the spatiotemporal variation of snow cover conditions from different aspects at the Northern Xinjiang and on the Central Tianshan Mountains, mainly in China, partly covering Kazakhstan and Kyrgyzstan. Secondly, Chapter 6 investigates the feasibility to indirectly map root-zone soil moisture using optical remote sensing techniques and in situ measurements. Specifically, covariation of root-zone soil moisture with the normalized difference of vegetation index (NDVI) from MODIS observation is studied at three sites (New Mexico, Arizona, and Texas). The three sites represent two types of vegetation (shrub and grass) and two types of climate conditions: arid/semi-arid (New Mexico and Arizona) and humid (Texas). Results show that the root-zone soil moisture has significant linear correlation with vegetation (NDVI). Finally, Chapter 7 validates and compares the NEXRAD Stage III and MPE precipitation products using a high density rain gauge network on the Upper Guadalupe River Basin of the Texas Hill Country in 2001 and 2004. (Abstract shortened by UMI.)

Wang, Xianwei

331

Applicability of leachates originating from solid-waste landfills for irrigation in landfill restoration projects.  

PubMed

Since, landfill areas are still the most widely used solid waste disposal method across the world, leachate generated from landfills should be given importance. Leachate of landfills exerts environmental risks mostly on surface and groundwater with its high pollutant content, which may cause unbearable water quality. This leads to the obligation for decontamination and remediation program to be taken into progress for the landfill area. Among a number of alternatives to cope with leachate, one is to employ the technology of phytoremediation. The main objective of this study was to determine the N accumulation ratios and the effects of landfill leachate in diluted proportions of chosen ratios (as 1/1, 1/2, 1/4, 0), on the growth and development of Cynodon dactylon, Stenotaphrum secundatum, Paspalum notatum, Pennisetum clandestinum, Mentha piperita, Rosmarinus officinalis, Nerium oleander, Pelargonium peltatum and Kochia scoparia species. In order to simulate the actual conditions of the landfill, soil covering the landfill is taken and used as medium for the trials. The study showed that S. secundatum, K. scoparia and N. oleander species had an impressive survival rate of 100%, being irrigated with pure leachate, while the others' survival rates were between 0 to 35% under the same conditions. As expected, application of leachate to the plants caused an increase in the accumulation of N, in the upper parts of all plants except P. peltatum. The highest N content increase was observed at S. Secundatum set, accumulating 3.70 times higher than its control set, whereas P. clandestinum value was 3.41 times of its control set. PMID:19295082

Erdogan, Reyhan; Zaimoglu, Zeynep; Sucu, M Yavuz; Budak, Fuat; Kekec, Secil

2008-09-01

332

Land-cover changes and potential impacts on soil erosion in the Nan watershed, Thailand  

Microsoft Academic Search

The expansion of built environments and agriculture land in the Nan watershed, Thailand, to support the rapid increase of the national population has resulted in deforestation, thus affecting the ecological balance. This deforestation, especially in high mountainous areas, has led to serious environmental degradation. Recent reports reveal an increasing soil-erosion problem in the watershed. This study analyses land-use and land-cover

Chamaporn Paiboonvorachat; Tonny J. Oyana

2011-01-01

333

Assessing the Biometeorology of a Newly Established Reclamation Soil Cover in Fort McMurray, Alberta  

NASA Astrophysics Data System (ADS)

Several experimental watersheds have been established in the Fort McMurray region as part of a risk-based assessment of various reclamation strategies for oil sands mining. This study has been undertaken to specifically evaluate if the most cost-effective reclamation option (minimal soil depth) can retain sufficient moisture to promote plant development and return the area to a functional boreal ecosystem. The eddy covariance technique was used during the second post-reclamation growing season to quantify the exchange of energy and water vapour atop a 25 cm soil cover, situated on a south facing slope. The 2008 growing season was both hotter and wetter than normal, resulting in large seasonal evapotranspiration (ET) values (309 mm from May 10th - Oct 8th). The majority of available energy was partitioned into latent heat, resulting in a mean Bowen ratio of 0.75 and a Priestley-Taylor alpha coefficient approaching unity (mean = 0.87). A low mean daytime (0900 to 1700 hrs) decoupling coefficient (? = 0.31), which decreased bi- weekly with increasing LAI, suggests that ET at this site was predominantly controlled by canopy resistance (rc). A total derivative analysis of the Penman-Monteith equation was used to demonstrate the sensitivity of ET to changes in available radiation (Ra), vapour pressure deficit (D) and rc between months. Results indicate that ET was particularly influenced by rc during the driest month of July when soil moisture became limited and the vegetation became stressed. ET was more sensitive to changes in D prior to leaf-out and during senescence. Although too early to predict whether this soil cover will be successful in sustaining regeneration, this study provides some insight into the unique biometeorology of the initial stages of engineered soil covers. Over time, this may allow for the detection of specific environmental indicators that may preclude the impending success or failure of reclamation efforts.

Goodbrand, S. C.; Carey, S. K.

2009-05-01

334

Occupational Exposure to Airborne Dust, Respirable Quartz and Metals Arising from Refuse Handling, Burning and Landfilling  

Microsoft Academic Search

Industrial hygiene investigations were conducted in 1983 at a refuse derived fuel (RDF) burning plant, a refuse transfer station and three municipal landfill sites. The field surveys were conducted during the warmer and drier seasons of the year. The investigations included air sampling for total dust, respirable quartz and airborne metals. Bulk samples of soil cover, precipitator\\/boiler ash and transfer

D. MOZZON; D. A. BROWN; J. W. SMITH

1987-01-01

335

OUTER LOOP LANDFILL CASE STUDY  

EPA Science Inventory

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

336

Sanitary landfill leachate  

SciTech Connect

This article reviews landfill leachate treatment methods. Contamination of groundwater, streams, and ponds by noxious materials from landfills in particular, leachate is a problem going back to the first dump''. However, it has only relatively recently received the attention it deserves. Leachate, soluble chemical compounds removed from degrading solid waste materials, is produced when water (usually from precipitation) passes through a landfill. Its quality varies with its source, among other factors, and reported values of leachate constituents vary over a wide range. The quantity produced is primarily a function of climate, but it is also affected by landfill cover and the collection system's configuration. Because uncollected leachate may contaminate ground-water or surface water, current regulations require containment, collection, treatment, and leachate disposal.

Shams-Khorzani, R.; Knox, T.D.; Brockway, R.C. (Black and Veatch, Kansas City, MO (United States))

1994-06-01

337

Parameterization of Organic-covered Permafrost Soils in Land Surface and Hydrological Models  

NASA Astrophysics Data System (ADS)

Close to one-third of the earth's surface is underlain with permafrost and much of the permafrost terrain is covered with a surface organic layer of various depths. The need to improve mathematical representation and parameterization of cold region processes in land surface and hydrological models have been well recognized in recent decades. However, progress has been hindered by (a) the complexity and variability of the soil system associated with thawing/freezing processes and organic cover and (b) the shortage of high quality field data due to the technical and logistic difficulties imposed by the harsh environments. Large variations exist in the parameterizations of thermal and hydrological processes in current land surface and hydrological models. Many of them were developed and validated in soil and climate conditions different from those in permafrost regions. In this study, efforts have been made to examine the most important thermal and hydraulic parameterizations and their effects on the simulations of ground thawing/freezing and infiltration/runoff processes against detailed measurements obtained at six field sites in Canada's discontinuous permafrost region. The tested parameterizations include (a) three methods for thermal conductivity, (b) three methods for hydraulic conductivity and soil water retention, (c) three methods for unfrozen water content, (d) six algorithms for thawing/freezing simulation and (e) five algorithms for infiltration simulation. The field sites cover various vegetation types including boreal forest, alpine tundra and wetland peat plateau. The soil organic depth ranges from 0.0 to 3 m. Field data used include daily meteorological variables (solar radiation, air temperature, relative humidity, precipitation and wind speed), daily liquid soil water content and soil temperature at various depths, and daily snow depth. Total soil water content (frozen and liquid) was monitored using twin probe gamma attenuation at three sites. Ground thawing and freezing depths, snow melt, infiltration and runoff were estimated from the above measurements. Methods of different parameterization were compared using identical inputs and evaluated against the same set of observed outputs. The main conclusions of this study include: (a) de Vries' method is recommended to parameterize the thermal conductivity in permafrost soils; (b) the van Genuchten method provides the best fit to the observed soil hydraulic curves, but has the most parameters. while the Brooks and Corey method and Clapp and Hornberger method achieve similar results for most soil moisture conditions as long as appropriate parameters were chosen; (c) the segmented linear function is the simplest to be parameterized with limited available data, while the water potential-freezing point depression equation is recommend for coupled thermal and moisture simulations; (d) a numerical model with an apparent heat capacity treatment gives the most accurate simulation of ground thawing/freezing depths in all the tested sites; and (e) no current infiltration scheme is valid for all the infiltration situations in organic-covered permafrost soils as different methods must be employed in different infiltration stages.

Zhang, Y.; Carey, S. K.; Quinton, W. L.; Janowicz, R.

2009-05-01

338

Influence of Snow Cover Duration on Soil Evaporation and Respiration Efflux in Mixed-conifer Ecosystems  

NASA Astrophysics Data System (ADS)

Subalpine mixed-conifer ecosystems are sensitive to a warming climate and are dependent on snowfall, which is expected to decrease under projected climate change. These changes in snowpack are likely to have important consequences for water and carbon cycling in these ecosystems and those downstream in the watersheds. Particularly within the semiarid southwest, such transitions to a drier and warmer environment will directly influence localized water and carbon dynamics and indirectly influence regional-scale levels of water availability and carbon sequestration. Therefore, in this study we monitored soil evaporation and respiration to evaluate how snow accumulation and duration of snow cover affected these effluxes. Our study took place within a mixed-conifer ecosystem within the Santa Catalina Mountains about 10 km north of Tucson, Arizona. Here, three understory time-lapse digital cameras have monitored snow cover within the footprint of an eddy covariance tower for nearly two years. Using these cameras, we identified locations with short and long snow duration. We then placed 6 soil collars (3 in short snow duration; 3 in long snow duration) within the field of view of each camera. Since July 2010, evaporation and soil respiration data have been collected regularly from these collars; soil temperature and soil moisture measurements were also collected. Our primary findings include: (1) evaporation fluxes do not vary drastically between long and short snow season sites, (2) evaporation fluxes for both short and long snow seasons have a strong relationship with soil moisture and a poor relationship with soil temperature, (3) CO2 fluxes vary noticeably between long and short snow season sites throughout the year, with short snow season fluxes typically higher than those of long snow season sites, and (4) CO2 fluxes for short and long snow seasons have a strong relationship with soil temperature and a poor relationship with soil moisture. Our findings suggest that rates of evaporative water loss will not be strongly influenced by changes in length of snow season, but that CO2 fluxes will be significantly influenced by these environmental changes such that we might expect greater carbon losses to the atmosphere.

Nelson, K.; Papuga, S. A.; John, G. P.; Minor, R.; Barron-Gafford, G. A.

2011-12-01

339

Infiltration through layered-soil trench covers: Response to an extended period of rainfall  

USGS Publications Warehouse

Four experimental waste disposal trench covers were constructed to test the effectiveness of layered-soil cover designs in reducing infiltration. Three covers each consisted of a layer of gravel between an overlying wick layer of compacted fine-grained material (either silt or loam) and a compacted loam base; the fourth consisted of compactd silt over a loam base. Capillary pressures were monitored at various depths within each cover during October through December, 1985, a period of high rainfall following a dry summer. Moisture movement in response to the rainfall was rapid within the upper layers of all four test covers, but was retained within the upper layers of the three wick-system trenches, despite variations in the design thickness and composition of the wick layers. In the wick systems, moisture did not enter the gravel until a threshold level of pressure approaching saturation was established in the wick layer. Once this level was reached, moisture moved into and through the gravel. This experiment demonstrates the functionality of field-scale wick systems. ?? 1988.

Larson, T. H.; Keefer, D. A.; Albrecht, K. A.; Cartwright, K.

1988-01-01

340

Comparative analysis of the soil cover diversity in floodplain areas of the Partizanskaya River valley (Sikhote-Alin Mountains)  

NASA Astrophysics Data System (ADS)

The regularities of the soil cover formation and pattern in the Partizanskaya River valley (Sikhote-Alin Mountains) were revealed. The diversity of the soil cover was shown to depend on the landscape hydrological zone of the river basin, the structure of the floodplain, and the difference in flooding of the floodplain sections. The comparative assessment of the soil cover diversity using the Shannon index showed that, in the zone of accumulative landscapes, the soil cover diversity of the floodplain sections that were formed under the meandering of the river was higher than the diversity of the soil cover in the sections formed upon branching (furcation) of the channel. The maximum values of the Shannon index and the maximum supply with water characterize the floodplain in the mouth zone of the valley with the most stable conditions of soil formation. The determination of the diversity index for the soil cover and water supply of the floodplain sections is expedient in planning the economic activities in the valley.

Nazarkina, A. V.

2010-12-01

341

Landfill methane oxidation across climate types in the U.S.  

PubMed

Methane oxidation in landfill covers was determined by stable isotope analyses over 37 seasonal sampling events at 20 landfills with intermediate covers over four years. Values were calculated two ways: by assuming no isotopic fractionation during gas transport, which produces a conservative or minimum estimate, and by assuming limited isotopic fractionation with gas transport producing a higher estimate. Thus bracketed, the best assessment of mean oxidation within the soil covers from chamber captured emitted CH(4) was 37.5 ± 3.5%. The fraction of CH(4) oxidized refers to the fraction of CH(4) delivered to the base of the cover that was oxidized to CO(2) and partitioned to microbial biomass instead of being emitted to the atmosphere as CH(4) expressed as a percentage. Air samples were also collected at the surface of the landfill, and represent CH(4) from soil, from leaking infrastructure, and from cover defects. A similar assessment of this data set yields 36.1 ± 7.2% oxidation. Landfills in five climate types were investigated. The fraction oxidized in arid sites was significantly greater than oxidation in mediterranean sites, or cool and warm continental sites. Sub tropical sites had significantly lower CH(4) oxidation than the other types of sites. This relationship may be explained by the observed inverse relationship between cover loading and fractional CH(4) oxidation. PMID:21133420

Chanton, Jeffrey; Abichou, Tarek; Langford, Claire; Hater, Gary; Green, Roger; Goldsmith, Doug; Swan, Nathan

2010-12-06

342

Size-fractionation and characterization of landfill leachate and the improvement of Cu{sup 2+} adsorption capacity in soil and aged refuse  

SciTech Connect

Leachate was collected from an anaerobic lagoon at Shanghai Laogang refuse landfill, the largest landfill in China, and the sample was separated into six fractions using micro-filtration membranes, followed by ultra-filtration membranes. Several parameters of the samples were measured, including chemical oxygen demand (COD), total organic carbon (TOC), total solids (TS), pH, total phosphate (TP), total nitrogen (TN), fixed solids (FS), NH{sub 4}{sup +}, orthophosphate, color, turbidity, and conductivity. These parameters were then quantitatively correlated with the molecular weight cutoff of the membrane used. Organic matter in the dissolved fraction (MW < 1 kDa) predominated in the leachate, accounting for 65% of TOC. Thermal infrared spectroscopy was used to characterize the filter residues. Asymmetric and symmetric stretching of methyl and methylene groups, and of functional groups containing nitrogen and oxygen atoms, were observed. In addition, the ability of two different samples to adsorb heavy metals was tested. Cu{sup 2+} was chosen as the representative heavy metal in this study, and the samples were soil; aged refuse, which had spent 8 years in a conventional sanitary landfill; and samples of soil and aged refuse treated for 48 h with leachate in the ratio of 5 g of sample per 50 ml of leachate. Cu{sup 2+} uptake by the raw soil was {approx}4.60 {mu}g/g, while uptake by the leachate-contacted soil and leachate-contacted aged refuse were 5.66 and 5.11 {mu}g/g, respectively. These results show that the organic matter in the leachate enhanced the capacity of aqueous solutions to adsorb Cu{sup 2+}.

Lou Ziyang [School of Environmental Science and Engineering, Shanghai Jiaotong University, Shanghai 200240 (China); State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Chai Xiaoli; Niu Dongjie; Ou Yuanyang [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Zhao Youcai [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)], E-mail: Zhaoyoucai@mail.tongji.edu.cn

2009-01-15

343

Size-fractionation and characterization of landfill leachate and the improvement of Cu2+ adsorption capacity in soil and aged refuse.  

PubMed

Leachate was collected from an anaerobic lagoon at Shanghai Laogang refuse landfill, the largest landfill in China, and the sample was separated into six fractions using micro-filtration membranes, followed by ultra-filtration membranes. Several parameters of the samples were measured, including chemical oxygen demand (COD), total organic carbon (TOC), total solids (TS), pH, total phosphate (TP), total nitrogen (TN), fixed solids (FS), NH4+, orthophosphate, color, turbidity, and conductivity. These parameters were then quantitatively correlated with the molecular weight cutoff of the membrane used. Organic matter in the dissolved fraction (MW<1kDa) predominated in the leachate, accounting for 65% of TOC. Thermal infrared spectroscopy was used to characterize the filter residues. Asymmetric and symmetric stretching of methyl and methylene groups, and of functional groups containing nitrogen and oxygen atoms, were observed. In addition, the ability of two different samples to adsorb heavy metals was tested. Cu2+ was chosen as the representative heavy metal in this study, and the samples were soil; aged refuse, which had spent 8 years in a conventional sanitary landfill; and samples of soil and aged refuse treated for 48h with leachate in the ratio of 5g of sample per 50ml of leachate. Cu2+ uptake by the raw soil was approximately 4.60microg/g, while uptake by the leachate-contacted soil and leachate-contacted aged refuse were 5.66 and 5.11microg/g, respectively. These results show that the organic matter in the leachate enhanced the capacity of aqueous solutions to adsorb Cu2+. PMID:18387289

Lou, Ziyang; Chai, Xiaoli; Niu, Dongjie; Ou, Yuanyang; Zhao, Youcai

2008-04-01

344

40 CFR 270.21 - Specific part B information requirements for landfills.  

Code of Federal Regulations, 2010 CFR

...description of how each landfill, including the...detection system, cover system, and appurtenances...description of how each landfill, including the liner and cover systems, will...describing the final cover which will be applied to each landfill or landfill...

2003-07-01

345

40 CFR 270.21 - Specific part B information requirements for landfills.  

Code of Federal Regulations, 2010 CFR

...description of how each landfill, including the...detection system, cover system, and appurtenances...description of how each landfill, including the liner and cover systems, will...describing the final cover which will be applied to each landfill or landfill...

2005-07-01

346

40 CFR 270.21 - Specific part B information requirements for landfills.  

Code of Federal Regulations, 2010 CFR

...description of how each landfill, including the...detection system, cover system, and appurtenances...description of how each landfill, including the liner and cover systems, will...describing the final cover which will be applied to each landfill or landfill...

2004-07-01

347

Nitrate-nitrogen, land use/land cover, and soil drainage associations at multiple spatial scales.  

PubMed

Managing non-point-source pollution of water requires knowledge of land use/land cover (LULC) influences at altering watershed scales. To gain improved understanding of relationships among LULC, soil drainage, and dissolved nitrate-N dynamics within the Calapooia River Basin in western Oregon, we selected 44 watersheds ranging in size between 3 and 33 km(2) for monthly synoptic sampling of surface water quality between October 2003 and September 2004. Seasonal associations were examined between dissolved nitrate-N and proportion of woody vegetation or poorly drained soils at differing scales (10, 20, 30, 60, 90, 150, 300 m, and entire watershed), which we defined as influence zones (IZs), surrounding stream networks. Correlations between nitrate-N and proportion woody vegetation or poorly drained soil at each IZ were analyzed for differences using the Hotelling-Williams test. We observed negative correlations (r = -0.81 to -0.94) between nitrate-N and proportion of woody vegetation during winter and spring. Poorly drained soils had positive correlations (r = 0.63-0.87) with nitrate-N. Altering the scale of analysis significantly changed correlations between nitrate-N and woody vegetation, with IZs <150 m being stronger than the watershed scale during winter. However, absolute differences in correlation values were small, indicating minimal ecological consequence for significant differences among scales. In contrast, nitrate-N correlations with poorly drained soil were stronger at the watershed scale than the 10- through 90-m IZs during winter and spring, and absolute differences were sufficient to suggest that scale is ecologically important when determining associations between dissolved nitrate-N and poorly drained soils. PMID:19465723

Floyd, William C; Schoenholtz, Stephen H; Griffith, Stephen M; Wigington, Parker J; Steiner, Jeffrey J

2009-05-20

348

Effect of turfgrass cover and irrigation on soil mobility and dissipation of mefenoxam and propiconazole.  

PubMed

Irrigation effects on pesticide mobility have been studied, but few direct comparisons of pesticide mobility or persistence have been conducted on turfgrass versus bare soil. The interaction of irrigation practices and the presence of turfgrass on the mobility and dissipation of mefenoxam [N-(2,6-dimethylphenyl)-N-(methoxyacetyl)-D-alanine methyl ester] and propiconazole (1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole) was studied. Sampling cylinders (20-cm diam.) were placed in either creeping bentgrass [Agrostis stolonifera L. var. palustris (Huds.) Farw.] or bare soil. Mefenoxam was applied at 770 g a.i. ha(-1) and propiconazole was applied at 1540 g a.i. ha(-1) on 14 June 1999. Sampling cylinders were removed 2 h after treatment and 4,8,16, 32, and 64 days after treatment (DAT) and the cores were sectioned by depth. Dissipation of mefenoxam was rapid, regardless of the amount of surface organic matter or irrigation. The half-life (t1/2) of mefenoxam was 5 to 6 d in turf and 7 to 8 d in bare soil. Most mefenoxam residues found in soil under turfgrass were in the 0- to 1-cm section at 0, 4, and 8 DAT. Residues were found in the 15- to 30-cm section at 4, 8, 16, 32, and 64 DAT, regardless of turf cover or irrigation. The t1/2 of propiconazole was 12 to 15 d in turfgrass and 29 d in bare soil. Little movement of propiconazole was observed in either bare soil or turf. PMID:11577867

Gardner, D S; Branham, B E

349

Biogenic NO emission from a spruce forest soil in the Fichtelgebirge (Germany) under the influence of different understorey vegetation cover  

NASA Astrophysics Data System (ADS)

Within the framework of the EGER project (ExchanGE processes in mountainous Regions) soil samples have been taken from the spruce forest site "Weidenbrunnen" (Fichtelgebirge, Germany) in September 2008 to determine the NO exchange in the laboratory and for a series of soil analyses. The soil was sampled below different understorey vegetation covers: young Norway spruce, moss/litter, blueberries and grass. We investigated the net NO release rate from corresponding organic layers as well as from the A horizon of respective soils. Additionally we measured pH, C/N ratio, contents of ammonium, nitrate, and organic C, bulk density, the thickness of the organic layer and the quality of the organic matter. Net NO release rates (as well as the NO production and NO consumption rates) from the soil samples were determined by a fully automated laboratory incubation & fumigation system. Purified dry air passed five dynamic incubation chambers, four containing water saturated soil samples and one reference chamber. By this procedure, the soil samples dried out slowly (within 2-6 days), covering the full range of soil moisture (0-300% gravimetric soil moisture). To quantify NO production and NO consumption rates separately, soil samples were fumigated with zero-air (approx. 0 ppb NO) and air of 133 ppb NO. The chambers were placed in a thermostatted cabinet for incubation at 10 an 20Ë? C. NO and H2O concentrations at the outlet of the five dynamic chambers were measured sequentially by chemiluminescence and IR-absorption based analyzers, switching corresponding valves every two minutes. Net NO release rates were determined from the NO concentration difference between soil containing and reference chambers. Corresponding measurements of H2O mixing ratio yielded the evaporation loss of the soil samples, which (referenced to the gravimetric soil water content before and after the incubation experiment) provided the individual soil moisture contents of each soil samples during the incubation experiment. Our contribution focus net NO release rates, NO production and NO consumption rates of spruce forest soils sampled under different understorey vegetation covers. Generally, organic layers show significant higher NO production and NO consumption rates than the soils from the corresponding A horizons. Soils under the understorey vegetation cover "moos/litter" revealed the lowest NO production and NO consumption rates. Net NO release rates, NO production and NO consumption rates of soil samples obtained below the four different under- storey vegetation covers will be discussed in terms of pH, C/N ratio, contents of ammonium, nitrate, and organic C, bulk density, thickness of organic layer, as well as quality of the organic matter.

Bargsten, A.; Andreae, M. O.; Meixner, F. X.

2009-04-01

350

Methane emissions from landfills in Serbia and potential mitigation strategies: a case study.  

PubMed

Open dumping and landfilling have represented the predominant method of waste management in Serbia during the past decades. This practice resulted in over 3600 waste disposal sites distributed all over the country. The locations of the sites and their characteristics have been determined in the framework of the presented study. The vast majority of disposal sites (up to 3300) are characterized by small deposition depth of waste and total waste volumes of less than 10,000 m(3). Only about 50 landfills in Serbia contain more than 100,000 m(3) of waste. These large landfills are responsible for more than 95% of the total CH(4) emissions from waste disposal, which was assessed as 60,000 tons of CH(4) in 2010. The evaluation of different measures [soil cover, compost cover and landfill gas (LFG) systems] for mitigating greenhouse gas emissions from Serbian landfills indicated that enhanced microbial CH(4) oxidation (using a compost cover), as well as the installation of LFG systems, could generate net revenues as saved CH(4) emissions are creditable for the European Greenhouse Gas Emissions Trading Scheme. In total between 4 and 7 million tons of CO(2) equivalent emissions could be avoided within the next 20 years by mitigating CH(4) emissions from Serbian landfills. PMID:22751946

Stanisavljevic, Nemanja; Ubavin, Dejan; Batinic, Bojan; Fellner, Johann; Vujic, Goran

2012-07-02

351

Technogenic contaminations of the soil-plant cover in the Primorsky Krai, Russia  

NASA Astrophysics Data System (ADS)

All economical development of the countries carries out monitoring as with the aim to estimate impact of the industrial enterprises and nuclear-energetic complexes as consequences of the nuclear accidents. The investigation the region of the Far East due to proximity to epicentre of accident on Fukushima-1 NPP is of a great interest. The aim of this work are radioecological investigations and estimate technogenic load on the ecosystems of tightly populated plots of the shore zone of the Vladivostok region. Eight plots were located on the investigated territory. The tree fall, forest litters and soils were sampling from the profile cuts of layer by layer, up to 20 cm. The artificial radionuclides (Sr-90 and Cs-134,137), as heavy metals and microelements (Co, Cu, Zn, Pb and Mn) content in the prepared samples was determined. The stock of Sr-90 fluctuates from 0.3 to 1.3 kBq/m2 and Cs-137 was from 0.4 to 3.0 kBq/m2 in the examined soils. On the whole, the level of the radionuclides content in the soil cover is within the limits of the background that was formed in the belt between 50° and 60° of northern latitude. The presence in investigated samples of Cs-134 indicates to contribution of accidental fallout of Fukushima-1 into contamination of the components of the natural ecosystems. In a year's time after the accident the stock of this isotope in the soils was 0.01-0.20 kBq/m^2. It is by factor of 10-100 lower than the stock of Cs-137. Taking into account that the ratio Cs-134/Cs-137 on the moment of accident was equal to unity (1:1). It can be estimated the quantity of Cs-137 entering into environment during post - accident period. This quantity was an average 0.03-0.30 kBq/m2 (with correction on radionuclides decay). The observation for the state of the soil cover includes the estimate of the level and peculiarities of distribution in the soils of heavy metals and microelements. Their content in the soils is formed from Clarke number and additional industrial gas-aerosol fallout. The analysis of a large volume data permitted to calculate the maximal level of the elements content in a soil under influence only natural factors. It was established, that maximal content of Co, Zn, Mn in these soils exceed of their Clarke's numbers. Minimal elements content was found for a tree fall. As a rule, this content is by factor of 10-100 lower than the Clarke values. Maximal concentration is in the soil layer. At the same time the additional technogenic fall-out produces the double increasing of the content of Cu and Pb in the soil layer. For the rest elements the concentrations increased on 8-32%. Acknowledgements. This work was supported by the grant for integrative research between the Ural and Far Eastern Branches of the Russian Academy of Sciences (12-C-4-1001).

Molchanova, Inna; Pozolotina, Vera; Mikhailovskaya, Ludmila; Antonova, Elena; Zhuravlev, Yury; Timofeeva, Yana; Burdukovsky, Maxim

2013-04-01

352

Alkaline solution neutralization capacity of soil.  

PubMed

Alkaline eluate from municipal solid waste (MSW) incineration residue deposited in landfill alkalizes waste and soil layers. From the viewpoint of accelerating stability and preventing heavy metal elution, pH of the landfill layer (waste and daily cover soil) should be controlled. On the other hand, pH of leachate from existing MSW landfill sites is usually approximately neutral. One of the reasons is that daily cover soil can neutralize alkaline solution containing Ca(2+) as cation. However, in landfill layer where various types of wastes and reactions should be taken into consideration, the ability to neutralize alkaline solutions other than Ca(OH)(2) by soil should be evaluated. In this study, the neutralization capacities of various types of soils were measured using Ca(OH)(2) and NaOH solutions. Each soil used in this study showed approximately the same capacity to neutralize both alkaline solutions of Ca(OH)(2) and NaOH. The cation exchange capacity was less than 30% of the maximum alkali neutralization capacity obtained by the titration test. The mechanism of neutralization by the pH-dependent charge can explain the same neutralization capacities of the soils. Although further investigation on the neutralization capacity of the soils for alkaline substances other than NaOH is required, daily cover soil could serve as a buffer zone for alkaline leachates containing Ca(OH)(2) or other alkaline substances. PMID:20395123

Asakura, Hiroshi; Sakanakura, Hirofumi; Matsuto, Toshihiko

2010-04-14

353

Black oat cover crop management effects on soil temperature and biological properties on a Mollisol in Texas, USA  

Technology Transfer Automated Retrieval System (TEKTRAN)

This field experiment was conducted to evaluate effects of mowing (no mowing, flail mowing, or sickle mowing) management of a black oat (Avena strigosa [Schreb.]) cover crop on soil microenvironmental conditions and on microbial biomass, dissolved organic C (DOC), soil inorganic N, resin-extractable...

354

Cover crops and sampling date effect on on-farm soil carbon pools under conservation tillage cotton  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cover crops may influence soil C sequestration and microbial activities by providing additional residue C to soil. We examined the influence of legume (crimson clover), nonlegume (rye), blend (a mixture of legumes containing balansa clover, hairy vetch, and crimson clover], and rye + blend mixture c...

355

Impact of cover crops on soil coservation in olive orchards under different agroecological conditions combing a conceptual soil water balance model (WABOL) and RUSLE.  

NASA Astrophysics Data System (ADS)

The effect of cover crops on soil conservation in olive orchards is evaluated based on a limited set of experiments based on runoff plots and model analysis on erosion models. However, the development of cover crops in olive growing areas is strongly controlled by the climate and soil conditions. These conditions are not completely represented in the empirical approach based on runoff plots, while in the modelling analysis approach (e.g. Gómez at Giráldez, 2009) it is usually necessary to make assumptions on the development of the cover crops to calibrate the erosion models that are poorly understood, such as for instance growing ob biomass and ground cover in areas significant colder or driers that those found in the literature, or its impact on the soil water balance. This communications presents a preliminary evaluation of the impact of cover crops in soil conservation in olive growing areas of Andalusia characterized y different soil, and climate conditions. The basic information has been taken from a recent study at national level (Hrnández, M.P., 2011) from which eight different growing areas characterized by different pluviometric and thermic regimes and soil conditions were selected. For those eight areas annual simulations of soil water content for an standard olive grove at 10x10 m under two different soil management techniques: cover crops with two option of cover crop killing in early or late spring; and conventional tillage, were simulated for a 8 to 10 year period based on a recently developed soil water balance model (WABOL, Abazi et al., 2012) which includes development of the cover crop. These results were used to calibrate RUSLE using the methodology proposed by Gómez et al. (2003) including the effect of different ground cover varying according to the conditions of different zones or climate of a particular year. The results of the simulations were used to compare the impact of the cover crop used in different areas on overall erosion risk and in soil water balance when the soil and climate variability (spatial and inter-annual) is included. The provide guidelines to adaption of cover crop management to the local conditions, although further analysis need to be made to include a broader range of conditions and the impact of irrigation.

Uran, A.; Lorite, I.; Gomez, J. A.

2012-04-01

356

Assessing the use of poplar tree systems as a landfill evapotranspiration barrier with the SHAW model.  

PubMed

The use of poplar tree systems (PTS) as evapotranspiration barriers on decommissioned landfills is gaining attention as an option for leachate management. This study involved field-testing the Simultaneous Heat and Water (SHAW) model for its ability to reliably estimate poplar transpiration, volumetric soil water content, and soil temperature at a landfill located in southern Ontario, Canada. The model was then used to estimate deep drainage and to ascertain the influence of a young PTS on the soil water balance of the landfill cover. The SHAW model tended to underestimate poplar transpiration [mean difference (MD) ranged from 0.33 to 3.55 mm on a daily total basis] and overestimate volumetric soil water content by up to 0.10 m3 m(-3). The model estimated soil temperature very well, particularly in the upper 1 m of the landfill cover (MD ranged from -0.1 to 1.6 x degrees C in this layer). The SHAW model simulations showed that deep drainage decreased appreciably with the presence of a young PTS largely through increased interception of rainfall, and that PTS have a good potential to act as effective evapotranspiration barriers in northern temperate climate zones. PMID:15462337

Preston, G M; McBride, R A

2004-08-01

357

Assessing Fractional Tree, Grass, and Bare Soil Cover from NDVI and Rainfall Time Series along the Kalahari Transect, Africa  

Microsoft Academic Search

Savanna ecosystems are water-limited, a characteristic that can be exploited to estimate fractional cover of trees, grass, and bare soil over large-scale areas from synthesis of remote sensing and rainfall measurements. A method is presented to estimate fractional cover components along the Kalahari Transect (KT), an aridity gradient in southern Africa, based upon the differing ways in which grasses and

T. M. Scanlon; J. D. Albertson; K. K. Caylor; C. A. Williams

2001-01-01

358

Methyl bromide emissions from a covered field: I. Experimental conditions and degradation in soil  

SciTech Connect

An experiment is described to investigate the environmental fate and transport of methyl bromide in agricultural systems. The experiment was designed to determine the dynamics of methyl bromide movement through soil, degradation, and total emissions to the atmosphere. This is of particular interest because it will allow an assessment of the environmental impacts (i.e., stratospheric ozone depletion) resulting from the agricultural use of methyl bromide. Methyl bromide was applied at a rate of 843 kg in a 3.5-ha (i.e., 240 kg/ha) field at a depth of 0.25 m and covered with a sheet of 1-mil polyethylene plastic. The maximum methyl bromide concentration in the atmosphere occurred at night between 0200 and 0600 h. During the first 3 d of the experiment, the maximum daily concentrations at 0.2 m above the soil surface were 30, 5, and 1 mg/(m{sup 3} of air), respectively. The trend of reduced emissions with time continued until the plastic was removed, when a momentary increase in the methyl bromide emissions occurred. The maximum soil gas concentration 24 h after injection was 30 g/m{sup 3} located at a 0.25-m depth. When the plastic was removed from the field (at 5.6 d), the maximum soil gas concentration was approximately 2 g/m{sup 3} at a 0.5-m depth. A mass-difference method for estimating the total methyl bromide emissions from the soil, based on degradation of methyl bromide to Br{sup -}, indicates that approximately 39% or 325 kg ({+-} 164 kg) of the applied methyl bromide was converted to Br{sup -} and, therefore, 61% or 518 kg ({+-} 164 kg) was lost via volatilization. 16 refs., 11 figs., 2 tabs.

Yates, S.R.; Gan, J.; Ernst, F.F. [Salinity Lab., Riverside, CA (United States)] [and others

1996-01-01

359

Effect of plant cover on distribution of soil organic matter pools  

NASA Astrophysics Data System (ADS)

Numerous studies reported that quality and quantity of primary production and also the rate of litter decomposition determine the carbon (C) content and its distribution in soils. Our objective was to examine how the type of plant cover affects C sequestration in the following pools: unprotected, spatial inaccessible, interacting with silt and clay, and biochemically protected SOM. The large lysimeters of Moscow State University allowed quantification of C stocks under broadleaf forest (Acer platanoides and Quercus robur), coniferous forest (Picea abies) and agricultural crops (9-field rotation), while other soil forming factors affecting SOC content were identical. In 1965 the lysimeters (S=9 m2, depth=1.5 m) were filled with carbonate free clay loam taken in Moscow region, originated from the Valday glaciation, and plant communities listed above were planted. We collected soil samples from the mineral horizons, from 0-5 cm depth, in spring 2012. The soils were physically separated by combination of the particle size and density fractionations (8 fractions in total), and C and N contents were analyzed. The total C and N contents in non-fractionated soil were higher under broadleaf forest (66 and 3.1 g kg-1), than under coniferous forest (34.5 and 1.23 g kg-1) and agricultural crops (13.7 and 0.9 g kg-1). Under forests 45-50% of Ctotal and 30% of Ntotal were in the unprotected pool, in agricultural soil these percentages were in 3 times less. The greatest portions of protected C were in spatial inaccessible pool: 28, 32 and 40% of the Ctotal for broadleaf forest, coniferous forest and agricultural crops, respectively. However, the total C amount in this pool under agricultural crops was in 3 times less, than under forests. This is indicative for the loss of C-rich macroaggregates and an increase of C-depleted microaggregates in agricultural soils due to the plowing. The amounts of C, stabilized by interactions with silt and clay, were nearly the same (3-6 g kg-1) because of the identical texture of soil parent material. The portion of biochemically protected C was maximal in agricultural soil - 27%, whereas on forest plots it was 2 times less. The amount of C in this pool did not strongly differ among the investigated soils, but C/N ratio was lower under agricultural crops than under forests. This indicates deeper degradation of organics in cultivated soil, N addition by fertilization, and a growing contribution of microbially-derived C to the biochemically protected pool. Wide C/N ratio in biochemically protected pool in the forest soils reflects the accumulation of primary recalcitrant plant substances with high C/N such as lignin and cellulose. Thus, forest vegetation contributes mainly to the SOM sequestration in the spatial inaccessible pool and is source of the high amount of non-protected C. Under agricultural crops however, the most of SOM is stabilized by interactions with silt and clay and is stabilized biochemically.

Gunina, Anna; Kuzyakov, Yakov; Ryzhova, Irina

2013-04-01

360

Effects of vegetation and soil-surface cover treatments on the hydrologic behavior of low-level waste trench caps  

SciTech Connect

Preliminary results are presented on a three-year field study at Los Alamos National Laboratory to evaluate the influence of different low-level radioactive waste trench cap designs on water balance under natural precipitation. Erosion plots having two different vegetative covers (shrubs and grasses) and with either gravel-mulched or unmulched soil surface treatments have been established on three different soil profiles on a decommissioned waste site. Total runoff and soil loss from each plot is measured after each precipitation event. Soil moisture is measured biweekly while plant canopy cover is measured seasonally. Preliminary results from the first year show that the application of a gravel mulch reduced runoff by 73 to 90%. Total soil loss was reduced by 83 to 93% by the mulch treatment. On unmulched plots, grass cover reduced both runoff and soil loss by about 50% compared to the shrub plots. Continued monitoring of the study site will provide data that will be used to analyze complex interactions between independent variables such rainfall amount and intensity, antecedent soil moisture, and soil and vegetation factors, as they influence water balance, and soil erosion. 18 refs., 2 figs., 3 tabs.

Lopez, E.A.; Barnes, F.J.; Antonio, E.J.

1988-01-01

361

Biomarker measurements in Trifolium repens and Eisenia fetida to assess the toxicity of soil contaminated with landfill leachate: a microcosm study.  

PubMed

To assess the toxicity of a soil contaminated with landfill leachate, biomarker measurements in two species living in close contact with the soil, i.e. a plant species Trifolium repens and an animal species Eisenia fetida, were conducted. Briefly, both species were studied after simultaneous exposure conducted in microcosms. The organisms were exposed to soil supplemented with pure leachate, leachate diluted to 50%; leachate diluted to 25% and without leachate. After a 10 weeks exposure period, we observed an increase in the Olive Trail Moment in T. repens, compared to the reference, for 50% and pure leachate. The response observed appears to be dose-dependent and linear in our experimental conditions. Addition of the leachate to the reference soil induced an increase in Cd-Metallothionein-coding mRNA quantity in E. fetida. In addition, expression level of another gene implied in detoxification and coding Phytochelatin synthase was significantly induced in worms exposed to the reference soil spiked with the leachate, regardless presence of T. repens. Thus, T. repens and E. fetida can be used in a complementary manner to assess soil quality. Sensitivities of the test species yield sensitive bioassays as both species responded at low doses despite the buffering effect of the soil. PMID:22520451

Manier, N; Brulle, F; Le Curieux, F; Vandenbulcke, F; Deram, A

2012-04-18

362

Town of Edinburg landfill reclamation demonstration project  

SciTech Connect

Landfill reclamation is the process of excavating a solid waste landfill to recover materials, reduce environmental impacts, restore the land resource, and, in some cases, extend landfill life. Using conventional surface mining techniques and specialized separation equipment, a landfill may be separated into recyclable material, combustible material, a soil/compost fraction and residual waste. A landfill reclamation demonstration project was hosted at the Town of Edinburg municipal landfill in northwest Saratoga County. The report examines various separation techniques employed at the site and appropriate uses for reclaimed materials. Specifications regarding engineered work plans, health and safety monitoring, and contingency preparedness are discussed. Major potential applications and benefits of using landfill reclamation technology at existing landfills are identified and discussed. The research and development aspect of the report also examines optimal screening technologies, site selection protocol and the results of a test burn of reclaimed waste at a waste-to-energy facility. Landfill reclamation costs are developed, and economic comparisons are made between reclamation costs and conventional landfill closure costs, with key criteria identified. The results indicate that, although dependent on site-specific conditions and economic factors, landfill reclamation can be a technically and economically feasible alternative or companion to conventional landfill closure under a range of favorable conditions. Feasibility can be determined only after an investigation of the variety of landfill conditions and reclamation options.

Not Available

1992-05-15

363

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

364

Effects of Cover Crop Systems on Soil Physical Properties and Carbon/Nitrogen Relationships in Coastal Plain Soils under Conservation Tillage  

Technology Transfer Automated Retrieval System (TEKTRAN)

Uncertainty exists concerning the impact of cover crops with conservation tillage on the total agricultural environment. A study conducted from 2002 – 2005 by USDA-ARS and the University of Georgia assessed the effects of cover crops on C/N sequestration and soil physical properties in a sandy coa...

365

Laboratory and numerical modeling of water balance in a layered sloped soil cover with channel flow pathway over mine waste rock  

Microsoft Academic Search

Macropores developed in barrier layers in soil covers overlying acid-generating waste rock may produce preferential flow through\\u000a the barrier layers and compromise cover performance. However, little has been published on the effects of preferential flow\\u000a on water balance in soil covers. In the current study, an inclined, layered soil cover with a 10-cm-wide sand-filled channel\\u000a pathway in a silty clay

Qing SongErnest; Ernest K. Yanful

2011-01-01

366

Impact of polypropylene fibers on desiccation cracking and hydraulic conductivity of compacted clay soils  

Microsoft Academic Search

Compacted clay soils are commonly used as hydraulic barriers in waste containment systems such as in liners and covers for landfills, impoundments, reservoirs, and ponds. Compacted clays can minimize infiltration of fluid into waste or control the release of contaminated fluids to the surrounding soils and groundwater. The hydraulic properties of these soil-based structures can be adversely affected by desiccation

Sami Mansour Rifai

2000-01-01

367

19th Annual landfill gas symposium  

SciTech Connect

This document contains the Proceedings of the 19th Annual Landfill Gas Symposium sponsored by the Solid Waste Association of America (SWANA), held on March 19-21, 1996 in Research Triangle Park near Raleigh, North Carolina, USA.The technical papers presented by the speakers cover a broad range of topics of interest to professionals in the municipal solid waste field. Technical sessions on the following subjects were presented: U.S. Landfill Gas Regulations, Control Technologies, Emission and Migration Control, Landfill Gas Generation Models, Field Practices, Case Studies of Landfill Gas Utilization, Global Methane Control, International Perspectives, and Emerging Technologies and Issues in the field of Landfill Gas Utilization.

NONE

1996-11-01

368

The influence of atmospheric pressure on landfill methane emissions  

SciTech Connect

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

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

2003-07-01

369

Predicting soil erosion under land-cover area and climate changes using the revised universal soil loss equation  

Microsoft Academic Search

Loss of soil has become a problem worldwide, and as concerns about the environment grow, active research has begun regarding soil erosion and soil-preservation polices. This study analyzed the trend of soil loss in South Korea over the past 30-year and predicted future soil loss in 2020 using the revised universal soil loss equation. In the period 1975-2005, soil loss

Soyoung Park; Cheunggil Jin; Chuluong Choi

2011-01-01

370

Arsenic concentration in porewater of an alkaline coal ash disposal site: Roles of siderite precipitation/dissolution and soil cover.  

PubMed

The geochemical behavior of As in porewaters of an alkaline coal ash disposal site was investigated using multilevel samplers. The disposal site was in operation from 1983 until 1994 and was covered with 0.3-0.5m thick soils in 2001 when this study was initiated. Sequential extraction analyses and batch leaching experiments were also performed using the coal ash samples collected from the disposal site. The results suggest the important roles of siderite (FeCO(3)) precipitation/dissolution and soil cover, which have been ignored previously. Arsenic levels in the porewater were very low (average of 10microgL(-1)) when the site was covered with soil due to coprecipitation with siderite. The soil cover enabled the creation of anoxic conditions, which raised the Fe concentration by the reductive dissolution of Fe-(hydr)oxides. Because of the high alkalinity generated from the alkaline coal ash, even a small increase in the Fe concentration (0.66mgL(-1) on average) could cause siderite precipitation. When the soil cover was removed, however, an oxidizing condition was created and triggered the precipitation of dissolved Fe as (hydr)oxides. As a result, the dissolution of previously precipitated As-rich siderite caused higher As concentration in the porewater (average of 345microgL(-1)). PMID:19682722

Kim, Kangjoo; Park, Sung-Min; Kim, Jinsam; Kim, Seok-Hwi; Kim, Yeongkyoo; Moon, Jeong-Tae; Hwang, Gab-Soo; Cha, Wang-Seog

2009-08-13

371

Landfill Gas Generation and Migration: Review of Current Research II.  

National Technical Information Service (NTIS)

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

J. Bogner M. Vogt R. Piorkowski

1989-01-01

372

Soil respiration and photosynthetic uptake of carbon dioxide by ground-cover plants in four ages of jack pine forest  

USGS Publications Warehouse

Soil carbon dioxide (CO2) emission (soil respiration), net CO2 exchange after photosynthetic uptake by ground-cover plants, and soil CO2 concentration versus depth below land surface were measured at four ages of jack pine (Pinus banksiana Lamb.) forest in central Saskatchewan. Soil respiration was smallest at a clear-cut site, largest in an 8-year-old stand, and decreased with stand age in 20-year-old and mature (60-75 years old) stands during May-September 1994 (12.1, 34.6, 31.5, and 24.9 mol C??m-2, respectively). Simulations of soil respiration at each stand based on continuously recorded soil temperature were within one standard deviation of measured flux for 48 of 52 measurement periods, but were 10%-30% less than linear interpolations of measured flux for the season. This was probably due to decreased soil respiration at night modeled by the temperature-flux relationships, but not documented by daytime chamber measurements. CO2 uptake by ground-cover plants ranged from 0 at the clear-cut site to 29, 25, and 9% of total growing season soil respiration at the 8-year, 20-year, and mature stands. CO2 concentrations were as great as 7150 ppmv in the upper 1 m of unsaturated zone and were proportional to measured soil respiration.

Striegl, R. G.; Wickland, K. P.

2001-01-01

373

Behaviour of Chimassorb 81 in the recycling process of agricultural films used as soil covers.  

PubMed

Two different films, low density polyethylene (LDPE) and an ethylene-vinyl acetate copolymer (EVA), used as agricultural soil covers were studied. The films were recycled five and ten times respectively, and both the tensile strength and the content of Chimassorb 81, a UV-stabilizer, were analysed in each cycle. Losses of 17.44% in tensile strength and 23.69% (Thermic film) and 13.22% (EVA) in the concentration of Chimassorb 81 were found after five recycling cycles. The extraction of Chimassorb 81 from the film is optimized. As these films can be recycled for the same application or even for use as food-contact materials, the standard migration tests with established simulants have been carried out. The results obtained are discussed. PMID:9064250

Nerín, C; Salafranca, J; Cacho, J

374

Reclamation of a burned forest soil with municipal waste compost: macronutrient dynamic and improved vegetation cover recovery.  

PubMed

The reclamation of burned soils in Mediterranean environments is of paramount importance in order to increase the levels of soil protection and minimise erosion and soil loss. The changes produced in the content of total organic carbon (TOC), N (Kjeldahl) and available P, K, Ca and Mg by the addition of different doses of a municipal solid waste compost to a burned soil were evaluated during one year. The effect of organic amendment on the improvement in the vegetation cover after one year was also evaluated. The organic amendment, particularly at a high dose, increased the TOC and N-Kjeldahl content of the soil in a closely related way. The levels of available K in soil were also enhanced by the organic amendment. Although the effects on all three parameters tended to decrease with time, their values in the amended soils were higher than in the control soil, which clearly indicates the improvement in the chemical quality of the soil brought about by the organic amendment. The available P content did not seem to be influenced by organic treatment, while available Mg levels were higher than in the control during the first 4 months following organic amendment. The application of compost to the burned soil improved its fertility and favoured rapid vegetal recovery, thus minimising the risk of soil erosion. PMID:11198173

Guerrero, C; Gómez, I; Moral, R; Mataix-Solera, J; Mataix-Beneyto, J; Hernández, T

2001-02-01

375

Emissions of air-borne mercury from five municipal solid waste landfills in Guiyang and Wuhan, China  

NASA Astrophysics Data System (ADS)

China disposes of bulk Municipal Solid Waste (MSW) by landfilling, resulting in a large quantity of mercury that enters landfills through waste. A detailed study on atmospheric mercury emissions from MSW landfills in China is necessary to understand mercury behavior from this source. Between 2003 and 2006, mercury airborne emissions through different pathways, as well as mercury speciation in Landfill Gas (LFG) were measured at 5 MSW landfills in Guiyang and Wuhan, China. The results showed that mercury content in the substrate increased the magnitude of mercury emissions, with the highest emission rate measured at the working face and in uncovered waste areas, and the lowest measured near soil covers and vegetated areas. Meteorological parameters, especially solar radiation, influenced the diurnal pattern of mercury surface-air emissions. Total Gaseous Mercury (TGM) in LFG varied from 2.0 to 1406.0 ng m-3, Monomethyl Mercury (MMHg) and Dimethyl Mercury (DMHg) in LFG averaged at 1.93 and 9.21 ng m-3, and accounted for 0.51% and 1.79% of the TGM in the LFG, respectively. Total mercury emitted from the five landfills ranged from 17 to 3300 g yr-1, with the highest from the working face, then soil covering, and finally the vent pipes.

Li, Z.-G.; Feng, X.; Li, P.; Liang, L.; Tang, S.-L.; Wang, S.-F.; Fu, X.-W.; Qiu, G.-L.; Shang, L.-H.

2010-04-01

376

Soil moisture changes under shrub cover (rosmarinus officinalis) and cleared shrub as response to precipitation in a semiarid environment: Stemflow effects  

Microsoft Academic Search

Variations in soil moisture after rainfall under Rosmarinus officinalis L and cleared shrub (prior cover R. officinalis) were analyzed. The results from the General Linear Model analysis showed the relevance of shrub plant cover on soil water infiltration in depth. A threshold of about 15–18 mm of rainfall was established, above which soil moisture changes tended to be positive. Moisture

J. Bellot

1997-01-01

377

Application of Digital Image Processing Integration with Satellite Remote Sensing and GIS in Land Use Land Cover Change and Soil Erosion  

Microsoft Academic Search

The relationship between land use land cover change s and soil erosion is investigated using digital imag e processing integrated with Remote Sensing The Universal Soil Loss Equation (USLE -Wischmeier and Smith, 1978) was applied to build a model to estimate the annual soil loss from the watershed in 1976 and 2002. The analysis process on land use land cover

Kyaw Zaya Htun; Lal Samarakoon

378

Soil cover patterns and land assessment in the Baikal region of Buryatia using the example of the Kabansk district  

NASA Astrophysics Data System (ADS)

The soil cover patterns in the Kabansk district (the Baikal region of the Buryat Republic), including the Selenga River delta, are analyzed. A soil map of this area has been developed on a scale of 1 : 500000. Stony organic soils are widespread in the tundra zone. Mountain-meadow soddy soils and tundra podburs (under dwarf pine) are formed at lower heights around lakes and in glacial valleys. Kabansk district includes taiga landscapes on the northern slopes of the Khamar-Daban Ridge with the predominance of podburs, podzols, soddy-taiga soils, and burozems. Agrolandscapes occur in the Nizhneselenginsk meadow-bog and forest-steppe natural region with a predominance of soddy forest, soddy gray forest, meadow, alluvial, meadow-bog, and bog soils. Data on the land evaluation in the agricultural part of the studied region are given.

Tsybikdorzhiev, Ts. Ts.; Khodoeva, S. O.; Gonchikov, B.-M. N.

2012-04-01

379

Estimation of long-term aqueous phase changes in a multi-layer cover using generic soil properties  

NASA Astrophysics Data System (ADS)

To protect near surface disposal facilities from infiltrating rainfall a multi-layer cover is installed consisting of different materials including soil (usually sand- or loam-based) and clay. The function of such layers is to divert infiltrating rainwater and hence minimize water drainage from the cover in the underlying disposal facility. However, the soil and clay materials will change the composition of the infiltrating water due to biogeochemical processes. A methodology is developed to assess changes in water composition as the rain water percolates through the soil and clay layers of a vegetated multi-layer cover. The method is based on a steady-state mass balance approach and uses generic soil physical and chemical properties. The approach considers weathering of the soil and clay minerals estimated from a pedotransfer function and accounts for the average temperature, the textural class and the depth of the profile. Soil microbiological activity is taken into account by imposing the soil partial pressure of CO2. The latter value is estimated from an empirical model based on the actual evapotranspiration. Eight scenarios were developed that resulted in eight different solution compositions of the drainage water. This approach resulted in a realistic pH range between 3.4 and 4.4 for the scenarios that consider either absence of all soil and clay layers (thus representing rain composition) or presence of a single soil layer only. Scenarios that considered both soil and clay layers to be present produced rather high pH values (around 9.5), probably due to too high estimates of the base cation weathering rates generated with the pedotransfer functions. Alternative methods for dealing with weathering of the clay layer are proposed. These types of water compositions were used to simulate the chemical degradation process of concrete as to produce a lower and upper bound to the durability of concrete engineered barriers.

Jacques, D.; Mallants, D.; Schneider, S.

2009-04-01

380

Effects of grazing on chemical soil properties and vegetation cover (case study: Kojour rangelands, Noushahr, Islamic Republic of Iran).  

PubMed

This research is conducted to study the effects of grazing on chemical soil properties and vegetation cover in three areas separated as the key, reference and critical areas. The study area is located at the river basin of Kojour in the Southwestern of Noushahr (in the North of IR-Iran). Sampling and collecting the soil and vegetation cover data from the site areas are accomplished in the first step of the research. The vegetation cover data was collected in 20 sample plots of 1 m2 in each area. The data was collected through a random- systematic method in the early grazing season. The soil data was collected out of two layers (0-10, 10-30 cm), in two time intervals before and after grazing. Five samples were selected per layer. Some edaphical factors such as organic carbon, percentage of soil organic matters, total nitrogen, absorbable phosphorus and potassium, pH and EC were measured. The results revealed that there is an inverse relationship between the grazing intensity and amount of carbon, nitrogen, soil organic matter and EC. However, a direct relation exists between the grazing intensity and amount of soil potassium, phosphorus, pH and the ratio of carbon to nitrogen. Vegetation in class 1 and 2 which were cereals and forbs had greatest percentage in the reference area. Furthermore, the percentage forage cover increases with the grazing intensity. The more unpalatable vegetation of class 3 forms the prevailing coverage in the critical area. The conclusion of this study shows that overgrazing is considered as a threat for the nutritional elements of soil and vegetation cover. PMID:19093501

Tamartash, R; Jalilvand, H; Tatian, M R

2007-12-15

381

Bringing new life to old landfills  

SciTech Connect

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

Rabasca, L.

1996-01-01

382

Variation in Aboveground Cover Influences Soil Nitrogen Availability at Fine Spatial Scales Following Severe Fire in Subalpine Conifer Forests  

Microsoft Academic Search

Following fire, fine-scale variation in early successional vegetation and soil nutrients may influence development of ecosystem\\u000a structure and function. We studied conifer forests burned by stand-replacing wildfire in Greater Yellowstone (Wyoming, USA)\\u000a to address two questions: (1) How do the variability and spatial structure of aboveground cover and soil nitrogen availability\\u000a change during the first 4 years following stand-replacing fire? (2)

Monica G. Turner; William H. Romme; Erica A. H. Smithwick; Daniel B. Tinker; Jun Zhu

383

Rainfall parameters and a cover model to predict runoff and soil loss from grazing trials in the Rhodesian sandveld  

Microsoft Academic Search

Annual runoff from a bare, sandy soil was well correlated to total seasonal precipitation quantities (P). In the case of veld treatments however, runoff was more closely related to higher precipitation levels (P50) on five of the six treatments.Soil losses were closely related to a parameter derived from the few major storms of the season (P12–25–20). A cover model was

H. A. Elwell; M. A. Stocking

1974-01-01

384

Soil quality regime in relation to land cover and slope position across a highly modified slope landscape  

Microsoft Academic Search

Vegetation and land-use mosaics of shrub land, grassland, farmland and reforested land are characteristic for residential areas of the Wolong nature reserve in Sichuan province, southwest China. The patterns represent a stage in long-term human disturbance and natural secondary succession since deforestation. The aim of this paper was to elucidate the soil-land cover types, soil-slope position relationships on a typical

Bo-Jie FU; Shi-Liang LIU; Li-Ding CHEN; Yi-He LÜ; Jun QIU

2004-01-01

385

Landfill gas-fired power plant pays cost of operating landfill  

SciTech Connect

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

Wallace, I.P.

1991-01-01

386

Strip-tilled Cover Cropping for Managing Nematodes, Soil Mesoarthropods, and Weeds in a Bitter Melon Agroecosystem  

PubMed Central

A field trial was conducted to examine whether strip-tilled cover cropping followed by living mulch practice could suppress root-knot nematode (Meloidogyne incognita) and enhance beneficial nematodes and other soil mesofauna, while suppressing weeds throughout two vegetable cropping seasons. Sunn hemp (SH), Crotalaria juncea, and French marigold (MG), Tagetes patula, were grown for three months, strip-tilled, and bitter melon (Momordica charantia) seedlings were transplanted into the tilled strips; the experiment was conducted twice (Season I and II). Strip-tilled cover cropping with SH prolonged M. incognita suppression in Season I but not in Season II where suppression was counteracted with enhanced crop growth. Sunn hemp also consistently enhanced bacterivorous and fungivorous nematode population densities prior to cash crop planting, prolonged enhancement of the Enrichment Index towards the end of both cash crop cycles, and increased numbers of soil mesoarthropods. Strip-tilled cover cropping of SH followed by clipping of the living mulch as surface mulch also reduced broadleaf weed populations up to 3 to 4 weeks after cash crop planting. However, SH failed to reduce soil disturbance as indicated by the Structure Index. Marigold suppressed M. incognita efficiently when planted immediately following a M. incognita-susceptible crop, but did not enhance beneficial soil mesofauna including free-living nematodes and soil mesoarthropods. Strip-tilled cover cropping of MG reduced broadleaf weed populations prior to cash crop planting in Season II, but this weed suppression did not last beyond the initial cash crop cycle.

Wang, Koon-Hui; Sipes, Brent S.; Hooks, Cerruti R.R.

2010-01-01

387

Long-term winter cover cropping effects on corn (Zea mays L.) production and soil nitrogen availability  

Microsoft Academic Search

This study was conducted to determine effects of long-term winter cover cropping with hairy vetch, cereal rye and annual\\u000a ryegrass on soil N availability and corn productivity. From 1987 to 1995, with the exception of the first year of the study,\\u000a the cover crops were seeded each year in late September or early October after the corn harvest and incorporated

S. Kuo; E. J. Jellum

2000-01-01

388

Influence of shrub species and biological soil crust cover on nutrient distribution in a semiarid sand dune area (Negev, Israel)  

NASA Astrophysics Data System (ADS)

Deserts are expanding and the restoration of barren lands is of great importance. To achieve this goal the understanding of soil-plant interactions is necessary. In semiarid systems the biogeochemical cycles are strongly linked to "fertile islands" which are surrounded by bare interspaces, areas mostly covered by biological soil crusts. These microbiological communities have great influence runoff, nutrient fixation and soil stability. This spatial horizontal pattern on the surface leads to vertical distribution patterns of nutrients. For a re-established sand dune system in the Negev (Israel) this pattern is highly depending on surface cover. Here unconsolidated sand dunes have been stabilised by the growth of biological soil crust leading to an establishment of perennial shrubs. After 15 years of landuse exclusion a clear spatial pattern in the amount of different soil cations and anions can be proofed. Our results show significant difference for potassium, manganese, calcium, sodium and chloride under biological soil crusts, the chenopod Anabasis articulata and the legume Retama raetam. This redistribution on behalf of biological processes can be shown for 3 study sites along a sharp precipitation gradient (90 mm per year up to 170 mm per year). The comparison of the study sites shows changes in the distribution patterns with increasing precipitation not only due to higher leaching or differences in dust input but changes in plant activity. The plant essential potassium proofs to be the best indicator for redistribution processes. The not plant essential sodium is non-normally distributed as Anabasis articulata and the biological soil crust accumulate this cation. Perennial shrubs and biological soil crusts are important ecosystem engineers. They have the ability to enrich ecosystems with cations and anions. The mechanisms of redistribution depend on soil cover and amount of precipitation and are, contradictory to earlier results, not independent from shrub species.

Drahorad, S.; Felix-Henningsen, P.

2009-04-01

389

Methanotrophs and methanotrophic activity in engineered landfill biocovers.  

PubMed

The dynamics and changes in the potential activity and community structure of methanotrophs in landfill covers, as a function of time and depth were investigated. A passive methane oxidation biocover (PMOB-1) was constructed in St-Nicéphore MSW Landfill (Quebec, Canada). The most probable number (MPN) method was used for methanotroph counts, methanotrophic diversity was assessed using denaturing gradient gel electrophoresis (DGGE) fingerprinting of the pmoA gene and the potential CH(4) oxidation rate was determined using soil microcosms. Results of the PMOB-1 were compared with those obtained for the existing landfill cover (silty clay) or a reference soil (RS). During the monitoring period, changes in the number of methanotrophic bacteria in the PMOB-1 exhibited different developmental phases and significant variations with depth. In comparison, no observable changes over time occurred in the number of methanotrophs in the RS. The maximum counts measured in the uppermost layer was 1.5x10(9) cells g dw(-1) for the PMOB-1 and 1.6x10(8) cells g dw(-1) for the RS. No distinct difference was observed in the methanotroph diversity in the PMOB-1 or RS. As expected, the potential methane oxidation rate was higher in the PMOB-1 than in the RS. The maximum potential rates were 441.1 and 76.0 microg CH(4) h(-1) g dw(-1) in the PMOB and RS, respectively. From these results, the PMOB was found to be a good technology to enhance methane oxidation, as its performance was clearly better than the starting soil that was present in the landfill site. PMID:19477627

Ait-Benichou, S; Jugnia, Louis-B; Greer, Charles W; Cabral, Alexandre R

2009-05-27

390

Soil erosion and sediment yield and their relationships with vegetation cover in upper stream of the Yellow River.  

PubMed

Soil erosion is a significant concern when considering regional environmental protection, especially in the Yellow River Basin in China. This study evaluated the temporal-spatial interaction of land cover status with soil erosion characteristics in the Longliu Catchment of China, using the Soil and Water Assessment Tool (SWAT) model. SWAT is a physical hydrological model which uses the RUSLE equation as a sediment algorithm. Considering the spatial and temporal scale of the relationship between soil erosion and sediment yield, simulations were undertaken at monthly and annual temporal scales and basin and sub-basin spatial scales. The corresponding temporal and spatial Normalized Difference Vegetation Index (NDVI) information was summarized from MODIS data, which can integrate regional land cover and climatic features. The SWAT simulation revealed that the annual soil erosion and sediment yield showed similar spatial distribution patterns, but the monthly variation fluctuated significantly. The monthly basin soil erosion varied from almost no erosion load to 3.92 t/ha and the maximum monthly sediment yield was 47,540 tones. The inter-annual simulation focused on the spatial difference and relationship with the corresponding vegetation NDVI value for every sub-basin. It is concluded that, for this continental monsoon climate basin, the higher NDVI vegetation zones prevented sediment transport, but at the same time they also contributed considerable soil erosion. The monthly basin soil erosion and sediment yield both correlated with NDVI, and the determination coefficients of their exponential correlation model were 0.446 and 0.426, respectively. The relationships between soil erosion and sediment yield with vegetation NDVI indicated that the vegetation status has a significant impact on sediment formation and transport. The findings can be used to develop soil erosion conservation programs for the study area. PMID:21071065

Ouyang, Wei; Hao, Fanghua; Skidmore, Andrew K; Toxopeus, A G

2010-11-11

391

Sunn Hemp: A Cover Crop for Southern and Tropical Farming Systems. Soil Quality-Agronomy Technical Note No. 10.  

National Technical Information Service (NTIS)

Do you want a cover crop that will increase organic matter, provide nitrogen, grow in low fertility sandy soils, and does not harbor nematodes. Sunn hemp (Crotalaria juncea L.) is a legume that when grown as a summer annual can produce over 5,000 pounds o...

1999-01-01

392

Development of a fully-distributed daily hydrologic feedback model addressing vegetation, land cover, and soil water dynamics (VELAS)  

NASA Astrophysics Data System (ADS)

Quantifying the impacts of vegetation-land cover on hydrologic feedbacks.Fully coupled water dynamics through the soil zone.Integration of VELAS modeling with GIS database.Flexibility of the VELAS model for different scale of time and space.

Park, Changhui; Lee, Jejung; Koo, Min-Ho

2013-06-01

393

YIELD AND SOIL NITRATE LEVELS OF COVER CROP AND LIVING-MULCH SYSTEMS FOR CORN SILAGE FERTILIZED WITH MANURE  

Technology Transfer Automated Retrieval System (TEKTRAN)

In replicated plots in southern Wisconsin, we compared yields and soil N levels of continuous corn grown with relay-seeded Italian ryegrass, fall-seeded rye, or no cover to a 2-year rotation of corn grown with kura clover living-mulch or relay-seeded red clover followed by one year of clover product...

394

Sampling and Mapping Soil Erosion Cover Factor for Fort Richardson, Alaska. Integrating Stratification and an Up-Scaling Method.  

National Technical Information Service (NTIS)

When a ground and vegetation cover factor related to soil erosion is mapped with the aid of remotely sensed data, a cost-efficient sample design to collect ground data and obtain an accurate map is required. However, the supports used to collect ground da...

G. Wang G. Gertner A. B. Anderson H. Howard

2006-01-01

395

EFFECTS OF FALL APPLICATION OF BROILER LITTER AND RYE WINTER COVER CROP ON COTTON YIELD AND SOIL N DYNAMICS  

Technology Transfer Automated Retrieval System (TEKTRAN)

This experiment was conducted on a Leeper silty clay loam soil at Mississippi Agricultural and Forestry Experimental Station (MAFES), Mississippi State, MS, in 2003 and will continue to 2006 to identify if rye winter cover crop over seeded to fall applied broiler litter benefits cotton growth and yi...

396

Soil Seed Banking in Pinyon-Juniper Areas With Differing Levels of Tree Cover, Understory Density and Composition  

Microsoft Academic Search

With removal of competitive pinyon-juniper overstory, endemic vegetation is released allowing germinating seed within the soil seed bank to establish. Density of seedlings is closely correlated with the density and composition of the understory community and tree cover. Considerable effort and costs are gener­ ally put into seeding areas following tree removal. If the amount and type of viable seed

Clare L. Poulsen; Scott C. Walker; Richard Stevens

397

The effect of dandelion or a cover crop on mycorrhiza inoculum potential, soil aggregation and yield of maize  

Microsoft Academic Search

A field experiment was conducted to observe the influence of a cover crop (winter wheat, Triticum aestivum L.), and a perennial weed (dandelion, Taraxacum officinale Weber ex Wigg.), on vesicular-arbuscular mycorrhiza (VAM) inoculum potential, soil aggregation, and maize yield after one season. Mycorrhizal colonization of maize roots was higher following the autumn planting of either winter wheat or dandelion compared

Z. Kabir; R. T. Koide

2000-01-01

398

Enzymatic Activity of a Mine Soil Varies According to Vegetation Cover and Level of Compost Applied  

Microsoft Academic Search

We applied three doses of compost from mixed municipal solid waste (0, 15, and 30 g kg of soil) to a soil developed on pyrite mine wastes. Part of the soil was planted with young Erica australis L. collected at the mine; part was fertilized with N-P-K-Mg and sown with Dactylis glomerata L. Bare soil without mineral fertilization was included

Amerilis de Varennes; Maria Manuela Abreu; Guiwei Qu; Cristina Cunha-Queda

2010-01-01

399

Predicting spatial and temporal patterns of soil temperature based on topography, surface cover and air temperature  

Microsoft Academic Search

Soil temperature is a variable that links surface structure to soil processes and yet its spatial prediction across landscapes with variable surface structure is poorly understood. In this study, a hybrid soil temperature model was developed to predict daily spatial patterns of soil temperature in a forested landscape by incorporating the effects of topography, canopy and ground litter. The model

S. Kang; S. Kim; S. Oh; D. Lee

2000-01-01

400

Physical properties of soils and the simulation of the hydrothermal regime for the complex soil cover of the Vladimir Opol'e region  

NASA Astrophysics Data System (ADS)

A methodological approach to the physically sound mathematical simulation of the hydrothermal regime for a complex soil cover on an agricultural field scale was proposed. To realize the approach, it is necessary (1) to restore the hydrothermal regime of two contrasting soils using a physically sound mathematical model on the basis of the experimental thermophysical and hydrophysical characteristics, (2) to adapt and optimize the model using the available experimental regime data, (3) to determine the hydrophysical and thermophysical properties for the entire plot under study using pedotransfer functions, and (4) to restore the hydrothermal regime of the entire soil plot using a mathematical model and the meteorological data for a specific time period. The proposed procedure allows simulating the hydrothermal regime of an agrogray soil complex in the Vladimir Opol'e region with a normalized standard error of about 8%. The analysis of the hydrothermal regime for the soil cover of the studied plot calculated from the meteorological data for the period from May to August of 2009 showed that the lower temperature values were confined to the areas of the agrogray soils with the second humus horizon: their average temperature was lower than the temperature of the agrogray soils by 0.44, 0.93, and 1.32°C at depths of 20, 40, and 70 cm, respectively, and the differences between their sums of the active temperatures for the considered period of 2009 reached 89 and 74°C at depths of 20 and 40 cm, respectively.

Shein, E. V.; Troshina, O. A.

2012-10-01

401

The Future Through the Past: The Use of Analog Sites for Design Criteria and Long Term Performance Assessment of Evapotranspiration Landfill Covers  

Microsoft Academic Search

There is growing support for using evapotranspiration (ET) covers for closure of low-level waste (LLW) and other types of waste disposal sites, particularly in the lower latitude arid regions of the western United States. At the Nevada Test Site (NTS), monolayer ET covers are the baseline technology for closure of LLW and mixed LLW cells. To better predict the long-term

D. S. Shafer; J. J. Miller; M. H. Young; S. C. Edwards; S. E. Rawlinson

2002-01-01

402

The future through the past: The use of analog sites for design criteria and long-term performance assessment of evapotranspiration landfill covers  

Microsoft Academic Search

There is growing support for using evapotranspiration (ET) covers for closure of low-level waste (LLW) and other types of waste disposal sites, particularly in the lower latitude arid regions of the western United States. For the Nevada Test Site (NTS), monolayer ET covers is the baseline technology for closure of LLW and mixed LLW cells. To better predict the long-term

David Shafer; Julianne Miller; Susan Edwards; Stuart Rawlinson

2001-01-01

403

Literature review of models for estimating soil erosion and deposition from wind stresses on uranium-mill-tailings covers  

SciTech Connect

Pacific Northwest Laboratory (PNL) is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon-suppression cover applied to uranium-mill tailings. The mechanics of wind erosion, as well as of soil deposition, are discussed in this report. Several wind erosion models are reviewed to determine if they can be used to estimate the erosion of soil from a mill-tailings cover. One model, developed by W.S. Chepil, contains the most-important factors that describe variables that influence wind erosion. Particular features of other models are also discussed, as well as the application of Chepil's model to a particular tailings pile. For this particular tailings pile, the estimated erosion was almost one inch per year for an unprotected tailings soil surface. Wide variability in the deposition velocity and lack of adequate deposition models preclude reliable estimates of the rate at which airborne particles are deposited.

Bander, T.J.

1982-11-01

404

Assessing the suitability of recycled plastics used as agricultural soil covers: migration study and experimental harvest.  

PubMed

The present work is focused on evaluating the suitability of recycling postconsumer agricultural plastic films again for the same use. The criteria to assess the suitability was based on migration study. Both overall and specific migration tests were performed, and the results obtained (ranging from 0.14 to 1.27 mg/dm(2) for overall migration and from not detectable to 6.98 microg/dm(2) for specific migration) show how, from this point of view, the recycled material can be safely proposed to be used again as agricultural soil covers. A theoretical discussion about the migration process is also presented and a simple mathematical model was applied to the data obtained, showing how total migration which is experimentally detected is theoretically predictable. These conclusions found were used to design and develop a controlled crop of tomato by using this recycled film. The use of the recycled plastic in the whole process and the behavior and properties of the pesticides absorbed in the postconsumer film are discussed. PMID:10563887

Nerín, C; Batlle, R

1999-01-01

405

Landfill gas extraction and purification technologies  

Microsoft Academic Search

The extraction and purification technologies of landfill gas (LFG) from municipal waste continue to generate strong environmental concerns. Historically, the focus of these concerns was an odour in the immediate region of the landfill and the risk of explosions in structures caused by the movement of LFG through soil. While these are still important environmental issues, health risks associated with

Valeriy Bekmuradov

2008-01-01

406

Development of surface-process models and correspondence principles for geophysical anomalies Geoelectrical investigation of oldrabandoned, covered landfill sites in urban areas: model development with a genetic diagnosis approach  

Microsoft Academic Search

Geoelectrical methods have an important, albeit difficult role to play in landfill investigations. In the present economic conditions, with the environmentally sensitive regime, adequate desk-study and model development are essential ingredients for a successful site investigation of landfills. This paper attempts to develop a genetic investigative model for old raban- doned landfill sites where the records of operations are not

Maxwell A. Meju

407

Effects of Cover Crop Systems on Soil Physical Properties and Carbon/Nitrogen Sequestration in Coastal Plain Soils Under Conservation Tillage  

Technology Transfer Automated Retrieval System (TEKTRAN)

Conservation practices are needed to prevent erosion and preserve soil and water quality. Conservation tillage has been found to be an effective environmental practice. Uncertainty exists concerning the impact of cover crops with conservation tillage on the total agricultural environment. A study...

408

Phytoremediation of landfill leachate  

SciTech Connect

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

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

2006-07-01

409

Soil vapor survey at the LLNL site 300 general services area, adjacent portions of the Connolly and Gallo Ranches and the site 300 landfill pit 6 area  

SciTech Connect

During October through December 1988, a soil vapor survey was conducted by Weiss Associates at the Lawrence Livermore National Laboratory Site 300 General Services Area (GSA), adjacent portions of the Connolly and Gallo Ranches, and at the Site 300 Landfill Pit 6 area. The purpose of the investigation was to aid in identifying the sources and the extent of trichloroethylene (TCE) previously found in ground water and soil at, or near, these sites. Using a soil vapor probe, samples were collected at 133 locations from depths of 2 to 15 ft below the surface. Analyses were initially done in the field using a Photovac portable gas chromatograph with a photoionization detector calibrated to detect TCE. During the later portion of the study a mobile laboratory was used that had a gas chromatograph equipped with both Hall electroconductivity and photoionization detectors. This permitted identification of the spectrum of EPA Method 601 volatile organic compounds (VOCs) by a modified EPA Method 8010. Extensive quality assurance/quality control (QA/QC) procedures were followed to ensure consistent system performance and no cross-contamination between samples or sites. Soil vapor concentrations were measured in parts per million on a volume to volume basis (ppM/sub v/v/). TCE concentrations detected in the soil vapor ranged from a high of 628 ppM/sub v/v/ to a low of not detected (ND) at less than 0.001--0.005 ppM/sub v/v/. The highest concentration was found next to monitor well W-7F, near a decommissioned drywell (sump) at the southern boundary of the GSA. Several locations exhibited ND concentrations. Fourteen locations analyzed by a mobile laboratory had tetrachloroethylene (PCE), 1,1-dichloroethylene (1,1-DCE) and/or 1,1,1-trichloroethane (1,1,1-TCA) at concentrations considerably lower than the TCE in the same sample. 17 refs., 15 figs., 2 tabs.

Vonder Haar, S.; Pavletich, J.; McIlvride, W.; Taffet, M.

1989-04-04

410

The effect of the land cover\\/vegetation category on spatial and temporal soil moisture variation  

Microsoft Academic Search

Soil moisture is an important component of the hydrological cycle. The capability to observe soil moisture frequently and over large regions could significantly improve our ability to estimate some hydrological parameters such as infiltration, runoff, and soil wetness, which are very useful in hydrological modeling, real-time flooding forecast and irrigation management. The primary intent of this project was to map

H. Ghedira; N. Jahan; R. Khanbilvardi

2004-01-01

411

EFFECTS OF TILLAGE SYSTEMS,ROTATIONS AND COVER CROP ON SOIL STRENGTH  

Technology Transfer Automated Retrieval System (TEKTRAN)

Continuous cotton (Gossypium hirsutum L.)production in the southern USA with intensive tillage has resulted in decreased soil quality. Conservation tillage can reverse this trend, but no-tillage often results in soil compaction problems. In May 2001, we determined soil strength from a long-term (22...

412

Health assessment for West Lake Landfill, Bridgeton, St. Louis County, Missouri, Region 7. CERCLIS No. MODO79900932. Preliminary report  

SciTech Connect

The West Lake Landfill, located in the City of Bridgeton, St. Louis County, Missouri, was proposed for the National Priorities List (NPL) in October 1989. Soil contaminated with radioactive waste from decontamination efforts at the Cotter Corporation's Latty Avenue plant in Hazelwood, Missouri, was dumped at the landfill in 1973. The radioactive soil was used as cover over refuse and in later years the radioactive soil itself was covered with additional soil and debris. The area around the landfill consists mostly of industrial buildings and business offices with small residential communities to the south and east. Agricultural river bottom land borders to the west, but it is fast being encroached upon by Earth City which is being developed for commercial purposes. The site presents no apparent public health hazard because the available data indicate human health is not currently being affected. Exposures of concern could occur if ground water contamination increases and spreads, exposed radioactive materials on the northwestern edges of the landfill move off site, or on-site worker exposure increases. Continued monitoring is recommended until additional environmental data are available to assess the on-site and off-site contamination and help predict future activity.

Not Available

1991-10-04

413

Influences of subsurface heterogeneity and vegetation cover on soil moisture, surface temperature and evapotranspiration at hillslope scales  

NASA Astrophysics Data System (ADS)

Physical processes are at the root of determining hydrologic response at all scales. Here, the physical mechanisms linking (1) subsurface heterogeneities to soil moisture and (2) resulting land-surface energy feedbacks to the atmosphere, are examined at the hillslope scale using a fully coupled surface-subsurface-land-surface model, ParFlow. A hillslope with a heterogeneous subsurface and uniform topography was modeled numerically using summer atmospheric conditions and a single precipitation event under controlled boundary conditions in order to isolate the contribution of hydraulic conductivity to land-surface hydrological processes and energy interactions. Patterns of subsurface hydraulic conductivity are shown to govern soil-moisture distribution at the hillslope scale following precipitation. This variability in soil moisture is closely linked to the variability in land-surface energy feedbacks. The role that vegetation plays in subsurface soil moisture and land ener