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Berlin Brandenburg

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  • 1
    Language: English
    In: Chemosphere, 2011, Vol.83(11), pp.1475-1479
    Description: Photodegradation on dried loamy sand was measured for OTNE and triclosan, and the shading effect was proved to be important and related to soil properties. ► Photodegradation of chemical compounds on dried loamy sand surfaces was measured. ► Photodegradation was not restricted by diffusion in soil but by the shading effect of light. ► The shading effect was quantified from the concentration decrease profile. Fragrances such as OTNE (marketed as Iso-E-Super®) and bactericides such as triclosan (marketed as Igrasan) are present in waste water and thus finally sorbed to sewage sludge. With that sludge they can reach agricultural fields where they potentially can undergo photodegradation processes. In this study the photodegradation of OTNE and triclosan on dried loamy sand was measured under artificial sunlight conditions in laboratory experiments. These compounds were artificially added with concentrations of 1 μg g on pre-rinsed dried loamy sand. The decrease in concentration with light irradiation was measured for 32 d in comparison to soil samples without light irradiation. The estimated light source intensity was 27 W m . Within the experiment, the apparent half-life was 7 and 17 d for OTNE and triclosan respectively. The decrease did not simply follow first-order kinetics. The apparent rate constant decreased in the latter stage of reaction, suggesting that part of the chemicals were inaccessible for degradation. Two models, i.e., a diffusion-limited model, and a light penetration-limited model, were used in comparison to the measured data to explain the observed degradation limitations in the latter stages of the experiments. Comparing the hereby obtained model parameters with estimated physico-chemical parameters for the soil and the two chemical compounds, the light penetration-limited model, in which the degradation in the soil surface layer is assumed to be limited due to the shading effect of light in the upper thin soil layer, showed to be the most realistic in describing the photodegradation.
    Keywords: Otne ; Triclosan ; Soil ; Photodegradation ; Chemistry ; Ecology
    ISSN: 0045-6535
    E-ISSN: 1879-1298
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  • 2
    Language: English
    In: Water Research, 01 May 2016, Vol.94, pp.120-127
    Description: Global warming and urbanization together with development of subsurface infrastructures (e.g. subways, shopping complexes, sewage systems, and Ground Source Heat Pump (GSHP) systems) will likely cause a rapid increase in the temperature of relatively shallow groundwater reservoirs (subsurface thermal pollution). However, potential effects of a subsurface temperature change on groundwater quality due to changed physical, chemical, and microbial processes have received little attention. We therefore investigated changes in 34 groundwater quality parameters during a 13-month enhanced-heating period, followed by 14 months of natural or enhanced cooling in a confined marine aquifer at around 17 m depth on the Saitama University campus, Japan. A full-scale GSHP test facility consisting of a 50 m deep U-tube for circulating the heat-carrying fluid and four monitoring wells at 1, 2, 5, and 10 m from the U-tube were installed, and groundwater quality was monitored every 1–2 weeks. Rapid changes in the groundwater level in the area, especially during the summer, prevented accurate analyses of temperature effects using a single-well time series. Instead, Dual-Well Analysis (DWA) was applied, comparing variations in subsurface temperature and groundwater chemical concentrations between the thermally-disturbed well and a non-affected reference well. Using the 1 m distant well (temperature increase up to 7 °C) and the 10 m distant well (non-temperature-affected), the DWA showed an approximately linear relationships for eight components (B, Si, Li, dissolved organic carbon (DOC), Mg , NH , Na , and K ) during the combined 27 months of heating and cooling, suggesting changes in concentration between 4% and 31% for a temperature change of 7 °C.
    Keywords: Subsurface Thermal Pollution ; Ground Source Heat Pump (Gshp) Systems ; Long-Term Heating and Cooling ; Confined Marine Aquifer ; Dual-Well Analysis (Dwa) ; Groundwater Quality ; Engineering
    ISSN: 0043-1354
    E-ISSN: 1879-2448
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  • 3
    Language: Japanese
    In: 地下水学会誌, 2014, Vol.56(1), pp.15-25
    Description: 再生可能エネルギー技術として,世界的に注目されている地中熱ヒートポンプ(GSHP)について,特にその利用に伴う地温変化が地下環境に与える影響を中心に,その規制やガイドラインに関しても現状を整理した。その結果,GSHP の利用に伴い,地温変化が生じることはいくつか報告されているが,それが誘発する潜在的な環境リスクについては,ほとんど研究例がないことが明らかになった。GSHP の利用における温度規制値やシステム間の最小距離などは,現状で経験的な観点から設定されているが,今後の持続的な利用に向けては,包括的で科学的な研究に取り組み,その結果を基に地下環境への影響を防止するための規制やガイドラインを定めることが極めて重要である。
    Description: The ground source heat pump (GSHP) system is gaining increasing popularity and use worldwide as one of the most promising renewable energy technologies. In this study, GSHP environmental impacts on the subsurface and the current status of regulations and guidelines were reviewed. Although subsurface temperature changes by utilization of GSHP systems have been observed in several studies, possible negative environmental impacts on the subsurface (labeled “thermal pollution”) have not been well investigated. Current regulations on maximum or minimum temperature thresholds and minimum distances between GSHP systems are only developed empirically and only 6 countries (all in Europe) have legally binding environmental regulations for operating GSHP systems. Our review suggests that for the sustainable usage of GSHP system, comprehensive scientific research on environmental impacts on the subsurface is needed to develop regulations or guidelines also taking into account risk assessment for subsurface thermal pollution.
    Keywords: 再生可能エネルギー ; 地中熱ヒートポンプ(GSHP) ; 地温変化 ; 環境リスク ; 持続的 ; Renewable Energy ; Ground Source Heat Pump (Gshp) ; Subsurface Temperature Change (Subsurface Thermal Pollution) ; Environmental Impact ; Sustainable Gshp Usage
    ISSN: 0913-4182
    E-ISSN: 21855943
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  • 4
    Language: English
    In: Soil Science Society of America journal, 2012, Vol.76(5), pp.1509-1517
    Description: The gas diffusion coefficient (Ds,g) and solute diffusion coefficient (D(s,l)) and their dependencies on fluid content (κ) (equal to soil–air content θ for D(s,g) and soil–water content ɛ for D(s,l)) are controlling factors for gas and solute transport in variably saturated soils. In this study, we propose unified, predictive models for D(s,g)(ɛ) and D(s,l)(θ) based on modifying and extending the classical Maxwell model at fluid saturation with a fluid-induced reduction term including a percolation threshold (ɛ(th) for D(s,g) and θ(th) for D(s,l)). Different percolation threshold terms adopted from recent studies for gas (D(s,g)) and solute (D(s,l)) diffusion were applied. For gas diffusion, ɛth was a function of bulk density (total porosity), while for solute diffusion θ(th) was best described by volumetric content of finer soil particles (clay and organic matter), FINES(vol). The resulting LIquid and GAs diffusivity and tortuosity (LIGA) models were tested against D(s,g) and D(s,l) data for differently-textured soils and performed well against the measured data across soil types. A sensitivity analysis using the new Maxwell’s Law based LIGA models implied that the liquid phase but not the gaseous-phase tortuosity was controlled by soil type. The analyses also suggested very different pathways and fluid-phase connectivity for gas and solute diffusion in unsaturated soil. In conclusion, the commonly applied strategy of using the same, soil-type-independent model for gas and solute diffusivity in analytical and numerical models for chemical transport and fate in variably-saturated soils appears invalid, except for highly sandy soils. The unified LIGA model with differing percolation thresholds for diffusion in the liquid and gaseous phases solves this problem. ; p. 1509-1517.
    Keywords: Clay ; Sandy Soils ; Bulk Density ; Solutes ; Mathematical Models ; Organic Matter ; Porosity ; Diffusivity
    ISSN: 0361-5995
    E-ISSN: 14350661
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  • 5
    Language: English
    In: Water science and technology : a journal of the International Association on Water Pollution Research, 2012, Vol.66(5), pp.983-92
    Description: The concentration of polycyclic aromatic hydrocarbons (PAHs) and the toxicity to marine bacteria (Vibrio fischeri) were measured for the organic solvent extracts of sea sediments collected from an urban watershed area (Hiroshima Bay) of Japan and compared with the concentrations and toxicity of atmospheric particulate matter (PM). In atmospheric PM, the PAHs concentration was highest in fine particulate matter (FPM) collected during cold seasons. The concentrations of sea sediments were 0.01-0.001 times those of atmospheric PM. 1/EC50 was 1-10 L g(-1) PM for atmospheric PM and 0.1-1 L g(-1) dry solids for sea sediments. These results imply that toxic substances from atmospheric PM are diluted several tens or hundreds of times in sea sediments. The ratio of the 1/EC50 to PAHs concentration ((1/EC50)/16PAHs) was stable for all sea sediments (0.1-1 L μg(-1) 16PAHs) and was the same order of magnitude as that of FPM and coarse particulate matter (CPM). The ratio of sediments collected from the west was more similar to that of CPM while that from the east was more similar to FPM, possibly because of hydraulic differences among water bodies. The PAHs concentration pattern analyses (principal component analysis and isomer ratio analysis) were conducted and the results showed that the PAHs pattern in sea sediments was quite different to that of FPM and CPM. Comparison with previously conducted PAHs analyses suggested that biomass burning residues comprised a major portion of these other sources.
    Keywords: Air Pollutants -- Chemistry ; Geologic Sediments -- Chemistry ; Particulate Matter -- Chemistry ; Polycyclic Aromatic Hydrocarbons -- Chemistry ; Water Pollutants, Chemical -- Chemistry
    ISSN: 0273-1223
    E-ISSN: 19969732
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  • 6
    Language: English
    In: Soil Science Society of America Journal, Nov-Dec, 2013, Vol.77(6), p.1944(11)
    Description: The time dependency of water repellency (WR) in hydrophobic porous media plays a crucial role for water infiltration processes after rainfall and for the long-term performance of capillary barrier systems. The contact angle (CA) of hydrophobic media normally decreases with continuous contact with water, eventually allowing water imbibition. However, the effect of the reduction in CA with soil-water contact time on the water retention function of hydrophobic media is not yet fully understood. In this study, water retention characteristics were measured using a hanging water column apparatus equipped with a mini-time domain reflectometry (TDR) coil probe under controlled wetting and drying in a water-repellent volcanic ash soil (VAS) and in sands coated with different hydrophobic agents. The contact angle (CA-SWRC) under imbibition was evaluated based on the inflection points on the water retention curves. For both water-repellent VAS and hydrophobized sand samples, the calculated CA-SWRC increased with increasing WR. This was determined from both the water drop penetration time and the initial contact angle (CAi) by the sessile drop method. Calculated CAuSWRC values ranged from 20[degrees] to 48[degrees] for the water-repellent VAS and from 40[degrees] to 63[degrees] for the hydrophobized sand. The CA reduction with contact time was quantified by relating CA-SWRC and CAi. This gave a significant linear relationship for the hydrophobized sand [CA-SWRC = 0.40CAi +11.3 (30[degrees] 〈 CAi 〈 120[degrees]), R2 = 0.66]. A large difference in water-filled pore distributions under controlled wetting and drying cycles was found on c
    Keywords: Water Repellents -- Usage ; Hydrophobic Effect -- Analysis ; Soil Research
    ISSN: 0361-5995
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  • 7
    Language: English
    In: Soil Science Society of America Journal, Sept-Oct, 2013, Vol.77(5), p.1517(12)
    Description: Time domain reflectometry (TDR) is used widely for measuring soil-water content. New TDR coil probe technology facilitates the development of small, nondestructive probes for simultaneous measurement of soil-water content (?) and soil-water potential (?). In this study we developed mini tensiometer-time domain reflectometry (T-TDR) coil probes, 6-mm wide and 32-mm long. The coil probes were calibrated against a conventional three-rod probe and were used for measuring ? for a aggregated volcanic ash soil (VAS) and a uniform sand. A commonly-used dielectric mixing model did not accurately describe the measured relation between the dielectric constant of the T-TDR coil probe (?coil) and ?, and a new calibration model for ?coil (?) was proposed instead. The new model assumes single-region behavior for sand and two-region behavior for aggregated VAS, when plotting the normalized dielectric constant of the coil probe (?coil-? dry; where ?dry is the dielectric constant of the T-TDR coil probe for air-dried material) as a function of ?. The new calibration model accurately described the (?coil-? dry)-? relations measured by 7 T-TDR coil probes on both sand and VAS. Additionally, there was a good agreement between measured soil-water retention curves (? 〉 -100 cm H2O) by the new T-TDR coil probes and independent measurements by the hanging water column method.
    Keywords: Reflectometers -- Usage ; Soil Research
    ISSN: 0361-5995
    E-ISSN: 14350661
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  • 8
    Language: English
    In: Soil Science Society of America journal, 2011, Vol.75(4), pp.1315-1329
    Description: Accurate predictions of the soil-gas diffusivity (Dp/Do, where Dp is the soil-gas diffusion coefficient and Do is the diffusion coefficient in free air) from easily measureable parameters like air-filled porosity (ε) and soil total porosity (ϕ) are valuable when predicting soil aeration and the emission of greenhouse gases and gaseous-phase contaminants from soils. Soil type (texture) and soil density (compaction) are two key factors controlling gas diffusivity in soils. We extended a recently presented density-corrected Dp(ε)/Do model by letting both model parameters (α and β) be interdependent and also functions of ϕ. The extension was based on literature measurements on Dutch and Danish soils ranging from sand to peat. The parameter α showed a promising linear relation to total porosity, while β also varied with α following a weak linear relation. The thus generalized density-corrected (GDC) model gave improved predictions of diffusivity across a wide range of soil types and density levels when tested against two independent data sets (total of 280 undisturbed soils or soil layers) representing Danish soil profile data (0–8 m below the ground surface) and performed better than existing models. The GDC model was further extended to describe two-region (bimodal) soils and could describe and predict Dp/Do well for both different soil aggregate size fractions and variably compacted volcanic ash soils. A possible use of the new GDC model is engineering applications such as the design of highly compacted landfill site caps. ; p. 1315-1329.
    Keywords: Data Collection ; Sand ; Soil Profiles ; Texture ; Landfills ; Prediction ; Engineering ; Soil Density ; Porosity ; Models ; Peat ; Greenhouse Gas Emissions ; Aeration ; Air ; Volcanic Ash Soils ; Diffusivity
    ISSN: 0361-5995
    E-ISSN: 14350661
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  • 9
    Language: English
    In: Soil Science Society of America journal, 2011, Vol.75(3), pp.795-806
    Description: The air permeability (ka) and soil gas diffusion coefficients (Dp) are controlling factors for gas transport and fate in variably saturated soils. We developed a unified model for ka and Dp based on the classical Archie's law, extended by: (i) allowing for two-region gas transport behavior for structured soils, with the natural field moisture condition (set at −100 cm H2O matric potential [pF 2]) as the reference (spliced) point between the large-pore (drained pore diameter ≥30 μm at pF ≤ 2) and the small-pore (subsequently drained pores 2) regions, and (ii) including a percolation threshold, set as 10% of the total porosity for structureless porous media or 10% of the porosity in the large-pore region for structured soils. The resulting extended Archie's law with reference point (EXAR) models for ka and Dp were fitted to the measured data. For both structureless and structured porous media, Archie's saturation exponent (n) was higher for Dp than for ka, indicating higher water blockage effects on gas diffusion. For structured soils, the saturation exponent for the large-pore region (n1) was lower than for the small-pore region (n2). Generally, n1 values of∼1 for ka and 2 for Dp and n2 values of 4/3 for ka and 7/3 for Dp described the data well. Two reference-point expressions for ka at pF 2 were also developed and tested together with existing models for Dp at pF 2 against independent data across soil types. The best-performing reference-point models were a ka model based on the classical Kozeny equation and the Moldrup Dp model. ; p. 795-806.
    Keywords: Models ; Water ; Soil Air ; Soil Types ; Porous Media ; Air ; Equations ; Permeability ; Porosity ; Diffusivity
    ISSN: 0361-5995
    E-ISSN: 14350661
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  • 10
    Language: English
    In: Journal of Geotechnical and Geoenvironmental Engineering, July, 2011, Vol.137(7), p.653(10)
    Description: Landfill sites have been implicated in greenhouse warming scenarios as a significant source of atmospheric methane. In this study, the effects of extreme compaction on the two main soil-gas transport parameters, the gas diffusion coefficient ([D.sub.p]) and the intrinsic air permeability ([k.sub.a]), and the cumulative methane oxidation rate in a landfill cover soil were investigated. Extremely compacted landfill cover soil exhibited negligible inactive soil-air contents for both [D.sub.p] and ka. In addition, greater [D.sub.p] and [k.sub.a] were observed as compared with normal compacted soils at the same soil-air content ([epsilon]), likely because of reduced water-blockage effects under extreme compaction. These phenomena are not included in existing predictive models for [D.sub.p]([epsilon]) and ka([epsilon]). On the basis of the measured data, new predictive models for [D.sub.p]([epsilon]) and ka([epsilon]) were developed with model parameters (representing air-filled pore connectivity and water-blockage effects) expressed as functions of dry density ([[rho].sub.b]). The developed [D.sub.p] ([epsilon]) and [k.sub.a] (e) models together with soil-water retention data for soils at normal and extreme compaction ([[rho].sub.b] = 1.44 and 1.85 g [cm.sup.-3]) implied that extremely compacted soils will exhibit lower [D.sub.p] and [k.sub.a] at natural field-water content (-100 cm [H.sub.2]O of soil-water matric potential) because of much lower soil-air content. Numerical simulations of methane gas transport, including a first-order methane oxidation rate, were performed for differently compacted soils by using the new predictive [D.sub.p]([epsilon]) model. Model results showed that compaction-induced difference in soil-air content at a given soil-water matric potential condition is likely the most important parameter governing methane oxidation rates in extremely compacted landfill cover soil. DOI: 10.1061/(ASCE)GT.1943-5606.0000459. CE Database subject headings: Landfills; Coverings; Gas; Parameters; Methane. Author keywords: Landfill final cover soil; Gas transport parameters; Compaction.
    Keywords: Atmospheric Carbon Dioxide -- Analysis ; Waste Management -- Analysis ; Methane -- Analysis ; Permeability -- Analysis ; Natural Gas Transmission -- Analysis
    ISSN: 1090-0241
    E-ISSN: 19435606
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