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Sample records for runoff leaching adsorption

  1. Adsorption and leaching of novel fungicide pyraoxystrobin on soils by 14C tracing method.

    Science.gov (United States)

    Liu, Xunyue; Wu, Huiming; Hu, Tingting; Chen, Xia; Ding, Xingcheng

    2018-01-19

    Pyraoxystrobin, (E)-2-(2-((3-(4-chlorophenyl)-1-methyl-1H-pyrazole-5-yloxy)methyl)phenyl)-3-methoxyacrylate, is a newly developed strobilurin fungicide with high antifungal efficiency. It has high potential to enter soil environments that might subsequently impact surface and groundwater. Therefore, 14 C-labeled pyraoxystrobin was used as a tracer to study the adsorption/desorption and migration behavior of this compound under laboratory conditions in three typical agricultural soils. The adsorption isotherms conformed with the Freundlich equation. Single factor analysis showed that organic matter content was the most important factor influencing the adsorption. The highest adsorption level was measured in soil with low pH and high organic carbon content. Once adsorbed, only 2.54 to 6.41% of the adsorbed compound could be desorbed. In addition, the mobility results from thin-layer chromatography and column leaching studies showed that it might be safe to use pyraoxystrobin as a fungicide without causing groundwater pollution from both runoff and leaching, which might be attributed to its strong hydrophobicity. High organic matter content enhanced pyraoxystrobin adsorption and desorption because of the rule of similarity (lipid solubility). In the column leaching study, 95.02% (minimum value) of the applied 14 C remained within the upper 4.0-cm layer after 60 days.

  2. Adsorption-desorption and leaching of pyraclostrobin in Indian soils.

    Science.gov (United States)

    Reddy, S Navakishore; Gupta, Suman; Gajbhiye, Vijay T

    2013-01-01

    Pyraclostrobin is a new broad-spectrum foliar applied and seed protectant fungicide of the strobilurin group. In this paper, adsorption-desorption of pyraclostrobin has been investigated in three different soils viz. Inceptisol (sandy loam, Delhi), Vertisol (sandy clay, Hyderabad) and Ultisol (sandy clay loam, Thrissur). Effect of organic matter and clay content on sorption was also studied in Inceptisol of Delhi. Leaching potential of pyraclostrobin as influenced by rainfall was studied in intact soil columns to confirm the results of adsorption-desorption studies. The adsorption studies were carried out at initial concentrations of 0.05, 0.1, 0.5, 1 and 1.5 μg mL(-1). The distribution coefficient (Kd) values in three test soils ranged from 4.91 to 18.26 indicating moderate to high adsorption. Among the three test soils, adsorption was the highest in Ultisol (Kd 18.26), followed by Vertisol (Kd 9.87) and Inceptisol (Kd 4.91). KF value was also highest for Ultisol soil (66.21), followed by Vertisol (40.88) and Inceptisol (8.59). S-type adsorption isotherms were observed in all the three test soils. Kd values in organic carbon-removed soil and clay-removed soil were 3.57 and 2.83 respectively, indicating lower adsorption than normal Inceptisol. Desorption studies were carried out at initial concentrations of 0.5, 1 and 1.5 μg mL(-1). Desorption was the greatest in Inceptisol, followed by Vertisol and Ultisol. Amounts of pyraclostrobin desorbed in three desorption cycles for different concentrations were 23.1-25.3%, 9.4-20.7% and 8.1-13.6% in Inceptisol, Vertisol and Ultisol respectively. Desorption was higher in clay fraction-removed and organic carbonremoved soils than normal Inceptisol. Desorption was slower than adsorption in all the test soils, indicating hysteresis effect (with hysteresis coefficient values varying from 0.05 to 0.20). Low values of hysteresis coefficient suggest high hysteresis effect indicating easy and strong adsorption, and slow

  3. Evaluating the Soil Vulnerability Index (SVI), an index to characterize inherent vulnerability of croplands to runoff and leaching

    Science.gov (United States)

    Soil erosion and nutrient loss from surface runoff and sub-surface flows are critical problems for croplands in the United States. Assessing cropland vulnerability to runoff and leaching is needed for watershed or regional land use and land management planning and conservation resources allocation. ...

  4. Gold and palladium adsorption from leached electronic scrap using ordered mesoporous carbon nanoscaffolds

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, Rocklan; Dutech, Guy

    2014-09-01

    Ordered mesoporous carbon (OMC) nanoscaffolds are engineered agglomerates of carbon nanotubes held together by small carbon nanofibers with uniform pore sizes, high pore volume, and high channel permeability. These materials exhibit very high affinity for the adsorption of gold from aqueous acidic mixtures. The efficiency of gold recovery is comparable to those typically accomplished using biopolymer-based adsorbents. The adsorption efficiency for other precious metals such as palladium and platinum is lower. Studies on the precious metal (Au, Pd) adsorption on OMC materials from actual liquors of leached electronics will be presented. Adsorption properties will be compared for several different sorbents used for the recovery of precious metals. The leach liquor compositions for three different types of electronic scrap materials (personal computer board, cell phone and tv input/output board) will be presented. The sorption efficiencies for Au, Pd, together with a spectrum of competing and non-competing metals, from such leach mixtures will be compared.

  5. Gold and palladium adsorption from leached electronic scrap using ordered mesoporous carbon nanoscaffolds

    International Nuclear Information System (INIS)

    McDowell, Rocklan; Dutech, Guy

    2014-01-01

    Ordered mesoporous carbon (OMC) nanoscaffolds are engineered agglomerates of carbon nanotubes held together by small carbon nanofibers with uniform pore sizes, high pore volume, and high channel permeability. These materials exhibit very high affinity for the adsorption of gold from aqueous acidic mixtures. The efficiency of gold recovery is comparable to those typically accomplished using biopolymer-based adsorbents. The adsorption efficiency for other precious metals such as palladium and platinum is lower. Studies on the precious metal (Au, Pd) adsorption on OMC materials from actual liquors of leached electronics will be presented. Adsorption properties will be compared for several different sorbents used for the recovery of precious metals. The leach liquor compositions for three different types of electronic scrap materials (personal computer board, cell phone and tv input/output board) will be presented. The sorption efficiencies for Au, Pd, together with a spectrum of competing and non-competing metals, from such leach mixtures will be compared.

  6. Chemical characterization, leach, and adsorption studies of solidified low-level wastes

    International Nuclear Information System (INIS)

    Walter, M.B.; Serne, R.J.; Jones, T.L.; McLaurine, S.B.

    1986-12-01

    Laboratory and field leaching experiments are beig conducted by Pacific Northwest Laboratory (PNL) to investigate the performance of solidified low-level nuclear waste in a typical, arid, near-surface disposal site. Under PNL's Special Waste Form Lysimeters-Arid Program, a field test facility was constructed to monitor the leaching of commercial solidified waste. Laboratory experiments were conducted to investigate the leaching and adsorption characteristics of the waste forms in contact with soil. Liquid radioactive wastes solidified in cement, vinyl ester-styrene, and bitumen were obtained from commercial boiling water and pressurized water reactors, and buried in a field leaching facility on the Hanford site in southeastern Washington State. Batch leaching, soil column adsorption, and soil/waste form column experiments were conducted in the laboratory, using small-scale cement waste forms and Hanford site ground water. The purpose of these experiments is to evaluate the ability of laboratory leaching tests to predict leaching under actual field conditions and to determine which mechanisms (i.e., diffusion, solubility, adsorption) actually control the concentration of radionuclides in the soil surrounding the waste form. Chemical and radionuclide analyses performed on samples collected from the field and laboratory experiments indicate strong adsorption of /sup 134,137/Cs and 85 Sr onto the Hanford site sediment. Small amounts of 60 Co are leached from the waste forms as very mobile species. Some 60 Co migrated through the soil at the same rate as water. Chemical constituents present in the reactor waste streams also found at elevated levels in the field and laboratory leachates include sodium, sulfate, magnesium, and nitrate. Plausible solid phases that could be controlling some of the chemical and radionuclide concentrations in the leachate were identified using the MINTEQ geochemical computer code

  7. Stormwater runoff mitigation and nutrient leaching from a green roof designed to attract native pollinating insects

    Science.gov (United States)

    Fogarty, S.; Grogan, D. S.; Hale, S. R.

    2013-12-01

    a rooftop? 2) How does this design compare with the performance of the extant Green Grid green roof system on the roof in regard to storm water runoff mitigation and nutrient leaching? and 3) Using GIS, can this information be scaled to a larger region (i.e. UNH campus, the NH Seacoast, NH cities, etc.) to determine areas of particular interest for pollinator conservation? Runoff mitigation, as a percentage of precipitation, is expected to be greater than that on the roof with proprietary substrate, though nutrient leaching may be greater as well due to the higher organic matter content. Paired with GIS data on NH ecoregions, these results will help to identify areas in the state that would benefit from the construction of pollinator habitat corridors, including urban areas that may not have been previously considered.

  8. Effects of soil type on leaching and runoff transport of rare earth elements and phosphorous in laboratory experiments.

    Science.gov (United States)

    Wang, Lingqing; Liang, Tao; Chong, Zhongyi; Zhang, Chaosheng

    2011-01-01

    Through leaching experiments and simulated rainfall experiments, characteristics of vertical leaching of exogenous rare earth elements (REEs) and phosphorus (P) and their losses with surface runoff during simulated rainfall in different types of soils (terra nera soil, cinnamon soil, red soil, loess soil, and purple soil) were investigated. Results of the leaching experiments showed that vertical transports of REEs and P were relatively low, with transport depths less than 6 cm. The vertical leaching rates of REEs and P in the different soils followed the order of purple soil > terra nera soil > red soil > cinnamon soil > loess soil. Results of the simulated rainfall experiments (83 mm h⁻¹) revealed that more than 92% of REEs and P transported with soil particles in runoff. The loss rates of REEs and P in surface runoff in the different soil types were in the order of loess soil > terra nera soil > cinnamon soil > red soil > purple soil. The total amounts of losses of REEs and P in runoff were significantly correlated.

  9. Laboratory leach tests of phosphate/sulfate waste grout and leachate adsorption tests using Hanford sediment

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R.J.; Martin, W.J.; McLaurine, S.B.; Airhart, S.P.; LeGore, V.L.; Treat, R.L.

    1987-12-01

    An assessment of the long-term risks posed by grout disposal at Hanford requires data on the ability of grout to resist leaching of waste species contained in the grout via contact with water that percolates through the ground. Additionally, data are needed on the ability of Hanford sediment (soil) surrounding the grout and concrete vault to retard migration of any wastes released from the grout. This report describes specific laboratory experiments that are producing empirical leach rate data and leachate-sediment adsorption data for Phosphate-Sulfate Waste (PSW) grout. The leach rate and adsorption values serve as inputs to computer codes used to forecast potential risk resulting from the use of ground water containing leached species. In addition, the report discusses other chemical analyses and geochemical computer code calculations that were used to identify mechanisms that control leach rates and adsorption potential. Knowledge of the controlling chemical and physical processes provides technical defensibility for using the empirical laboratory data to extrapolate the performance of the actual grout disposal system to the long time periods of interest. 59 refs., 83 figs., 18 tabs.

  10. Laboratory leach tests of phosphate/sulfate waste grout and leachate adsorption tests using Hanford sediment

    International Nuclear Information System (INIS)

    Serne, R.J.; Martin, W.J.; McLaurine, S.B.; Airhart, S.P.; LeGore, V.L.; Treat, R.L.

    1987-12-01

    An assessment of the long-term risks posed by grout disposal at Hanford requires data on the ability of grout to resist leaching of waste species contained in the grout via contact with water that percolates through the ground. Additionally, data are needed on the ability of Hanford sediment (soil) surrounding the grout and concrete vault to retard migration of any wastes released from the grout. This report describes specific laboratory experiments that are producing empirical leach rate data and leachate-sediment adsorption data for Phosphate-Sulfate Waste (PSW) grout. The leach rate and adsorption values serve as inputs to computer codes used to forecast potential risk resulting from the use of ground water containing leached species. In addition, the report discusses other chemical analyses and geochemical computer code calculations that were used to identify mechanisms that control leach rates and adsorption potential. Knowledge of the controlling chemical and physical processes provides technical defensibility for using the empirical laboratory data to extrapolate the performance of the actual grout disposal system to the long time periods of interest. 59 refs., 83 figs., 18 tabs

  11. Pesticide leaching by agricultural drainage in sloping, mid-textured soil conditions - the role of runoff components.

    Science.gov (United States)

    Zajíček, Antonín; Fučík, Petr; Kaplická, Markéta; Liška, Marek; Maxová, Jana; Dobiáš, Jakub

    2018-04-01

    Dynamics of pesticides and their metabolites in drainage waters during baseflow periods and rainfall-runoff events (RREs) were studied from 2014 to 2016 at three small, tile-drained agricultural catchments in Bohemian-Moravian Highlands, Czech Republic. Drainage systems in this region are typically built in slopes with considerable proportion of drainage runoff originating outside the drained area itself. Continuous monitoring was performed by automated samplers, and the event hydrograph was separated using 18 O and 2 H isotopes and drainage water temperature. Results showed that drainage systems represent a significant source for pesticides leaching from agricultural land. Leaching of pesticide metabolites was mainly associated with baseflow and shallow interflow. Water from causal precipitation diluted their concentrations. The prerequisites for the leaching of parental compounds were a rainfall-runoff event occurring shortly after spraying, and the presence of event water in the runoff. When such situations happened consequently, pesticides concentrations in drainage water were high and the pesticide load reached several grams in a few hours. Presented results introduce new insights into the processes of pesticides movement in small, tile-drained catchments and emphasizes the need to incorporate drainage hydrology and flow-triggered sampling into monitoring programmes in larger catchments as well as in environment-conservation policy.

  12. Runoff and leaching of metolachlor from Mississippi River alluvial soil during seasons of average and below-average rainfall.

    Science.gov (United States)

    Southwick, Lloyd M; Appelboom, Timothy W; Fouss, James L

    2009-02-25

    The movement of the herbicide metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] via runoff and leaching from 0.21 ha plots planted to corn on Mississippi River alluvial soil (Commerce silt loam) was measured for a 6-year period, 1995-2000. The first three years received normal rainfall (30 year average); the second three years experienced reduced rainfall. The 4-month periods prior to application plus the following 4 months after application were characterized by 1039 +/- 148 mm of rainfall for 1995-1997 and by 674 +/- 108 mm for 1998-2000. During the normal rainfall years 216 +/- 150 mm of runoff occurred during the study seasons (4 months following herbicide application), accompanied by 76.9 +/- 38.9 mm of leachate. For the low-rainfall years these amounts were 16.2 +/- 18.2 mm of runoff (92% less than the normal years) and 45.1 +/- 25.5 mm of leachate (41% less than the normal seasons). Runoff of metolachlor during the normal-rainfall seasons was 4.5-6.1% of application, whereas leaching was 0.10-0.18%. For the below-normal periods, these losses were 0.07-0.37% of application in runoff and 0.22-0.27% in leachate. When averages over the three normal and the three less-than-normal seasons were taken, a 35% reduction in rainfall was characterized by a 97% reduction in runoff loss and a 71% increase in leachate loss of metolachlor on a percent of application basis. The data indicate an increase in preferential flow in the leaching movement of metolachlor from the surface soil layer during the reduced rainfall periods. Even with increased preferential flow through the soil during the below-average rainfall seasons, leachate loss (percent of application) of the herbicide remained below 0.3%. Compared to the average rainfall seasons of 1995-1997, the below-normal seasons of 1998-2000 were characterized by a 79% reduction in total runoff and leachate flow and by a 93% reduction in corresponding metolachlor movement via these routes

  13. Uranium adsorption from the sulphuric acid leach liquor containing more chlorides with cation-exchange resin SL-406

    International Nuclear Information System (INIS)

    Hu Jun; Wang Zhaoguo; Chi Renqing; Niu Xuejun

    1994-01-01

    The feasibility of uranium adsorption was studied from the sulphuric acid leach liquor of a uranium ore containing more chlorides with cation-exchange resin SL-406. The influence of some factors on uranium adsorption was investigated. It was shown that the resin possesses better selectivity, stability and higher capacity. It can be effectively used to recovery uranium from leach liquors of uranium ores containing more chlorides

  14. Effect of charcoal amendment on adsorption, leaching and degradation of isoproturon in soils

    Science.gov (United States)

    Si, Youbin; Wang, Midao; Tian, Chao; Zhou, Jing; Zhou, Dongmei

    2011-04-01

    The effects of charcoal amendment on adsorption, leaching and degradation of the herbicide isoproturon in soils were studied under laboratory conditions. The adsorption data all fitted well with the Freundlich empirical equation. It was found that the adsorption of isoproturon in soils increased with the rate of charcoal amended (correlation coefficient r = 0.957 **, P isoproturon in leachate decreased with the increase of the amount of charcoal addition to soil column, while the retention of isoproturon in soils increased with an increase in the charcoal content of soil samples. Biodegradation was still the most significant mechanism for isoproturon dissipation from soil. Charcoal amendment greatly reduced the biodegradation of isoproturon in soils. The half-lives of isoproturon degradation ( DT50) in soils greatly extended when the rate of added charcoal inceased from 0 to 50 g kg - 1 (for Paddy soil, DT50 values increased from 54.6 to 71.4 days; for Alfisol, DT50 from 16.0 to 136 days; and for Vertisol, DT50 from 15.2 to 107 days). The degradation rate of isoproturon in soils was significantly negatively correlated with the amount of added charcoal. This research suggests that charcoal amendment may be an effective management practice for reducing pesticide leaching and enhancing its persistence in soils.

  15. Leaching potential of chlorpyrifos in an Andisol and Entisol: adsorption-desorption and degradation studies

    Science.gov (United States)

    Mosquera-Vivas, Carmen; Walther Hansen, Eddy; Garcia-Santos, Glenda; Obregón-Neira, Nelson; Celis-Ossa, Raul Ernesto; González-Murillo, Carlos Alberto; Juraske, Ronnie; Hellweg, Stefanie; Guerrero-Dallos, Jairo Arturo

    2017-04-01

    Ecological status of tropical soils like high OC content and microbial activity plays a key role to reduce the leaching of insecticide chlorpyrifos through the soil profile and therefore into groundwater. We found that chlorpyrifos has "transitional" leaching potential (GUS values varied between 1.8 and 2.5) throughout the soil depth, which differs from the "nonleacher" classification for temperate soils as based on surface level t1/2 and Koc values from international databases. These findings provide strong evidence of the importance of estimating the transport parameters and insecticide concentrations in different soil layers, especially when the amount and type of OC content vary throughout the soil profile. We got to such conclusions after studying the soil profile structural composition of soil organic matter and the adsorption/desorption characteristics of the insecticide in two different soil profiles (Andisol and Entisol) under agriculture production using Fourier transform infrared spectroscopy, nuclear magnetic resonance, and batch analysis methods.

  16. Mineral-leaching chemical transport with runoff and sediment from severely eroded rare-earth tailings in southern China

    Science.gov (United States)

    Lu, Huizhong; Cao, Longxi; Liang, Yin; Yuan, Jiuqin; Zhu, Yayun; Wang, Yi; Gu, Yalan; Zhao, Qiguo

    2017-08-01

    Rare-earth mining has led to severe soil erosion in southern China. Furthermore, the presence of the mineral-leaching chemical ammonium sulfate in runoff and sediment poses a serious environmental threat to downstream water bodies. In this paper, the characteristics of mineral-leaching chemicals in surface soil samples collected in the field were studied. In addition, NH4+ and SO42- transport via soil erosion was monitored using runoff and sediment samples collected during natural rainfall processes. The results demonstrated that the NH4+ contents in the surface sediment deposits increased from the top of the heap (6.56 mg kg-1) to the gully (8.23 mg kg-1) and outside the tailing heap (13.03 mg kg-1). The contents of SO42- in the different locations of the tailing heaps ranged from 27.71 to 40.33 mg kg-1. During typical rainfall events, the absorbed NH4+ concentrations (2.05, 1.26 mg L-1) in runoff were significantly higher than the dissolved concentrations (0.93, 1.04 mg L-1), while the absorbed SO42- concentrations (2.87, 1.92 mg L-1) were significantly lower than the dissolved concentrations (6.55, 7.51 mg L-1). The dissolved NH4+ and SO42- concentrations in runoff displayed an exponentially decreasing tendency with increasing transport distance (Y = 1. 02 ṡ exp( - 0. 00312X); Y = 3. 34 ṡ exp( - 0. 0185X)). No clear trend with increasing distance was observed for the absorbed NH4+ and SO42- contents in transported sediment. The NH4+ and SO42- contents had positive correlations with the silt and clay ratio in transported sediment but negative correlations with the sand ratio. These results provide a better understanding of the transport processes and can be used to develop equations to predict the transport of mineral-leaching chemicals in rare-earth tailings, which can provide a scientific foundation for erosion control and soil management in rare-earth tailing regions in southern China.

  17. Mineral-leaching chemical transport with runoff and sediment from severely eroded rare-earth tailings in southern China

    Directory of Open Access Journals (Sweden)

    H. Lu

    2017-08-01

    Full Text Available Rare-earth mining has led to severe soil erosion in southern China. Furthermore, the presence of the mineral-leaching chemical ammonium sulfate in runoff and sediment poses a serious environmental threat to downstream water bodies. In this paper, the characteristics of mineral-leaching chemicals in surface soil samples collected in the field were studied. In addition, NH4+ and SO42− transport via soil erosion was monitored using runoff and sediment samples collected during natural rainfall processes. The results demonstrated that the NH4+ contents in the surface sediment deposits increased from the top of the heap (6.56 mg kg−1 to the gully (8.23 mg kg−1 and outside the tailing heap (13.03 mg kg−1. The contents of SO42− in the different locations of the tailing heaps ranged from 27.71 to 40.33 mg kg−1. During typical rainfall events, the absorbed NH4+ concentrations (2.05, 1.26 mg L−1 in runoff were significantly higher than the dissolved concentrations (0.93, 1.04 mg L−1, while the absorbed SO42− concentrations (2.87, 1.92 mg L−1 were significantly lower than the dissolved concentrations (6.55, 7.51 mg L−1. The dissolved NH4+ and SO42− concentrations in runoff displayed an exponentially decreasing tendency with increasing transport distance (Y = 1. 02 ⋅ exp( − 0. 00312X; Y = 3. 34 ⋅ exp( − 0. 0185X. No clear trend with increasing distance was observed for the absorbed NH4+ and SO42− contents in transported sediment. The NH4+ and SO42− contents had positive correlations with the silt and clay ratio in transported sediment but negative correlations with the sand ratio. These results provide a better understanding of the transport processes and can be used to develop equations to predict the transport of mineral-leaching chemicals in rare-earth tailings, which can provide a scientific foundation for erosion control and soil management in rare

  18. Leaching of additives from construction materials to urban storm water runoff.

    Science.gov (United States)

    Burkhardt, M; Zuleeg, S; Vonbank, R; Schmid, P; Hean, S; Lamani, X; Bester, K; Boller, M

    2011-01-01

    Urban water management requires further clarification about pollutants in storm water. Little is known about the release of organic additives used in construction materials and the impact of these compounds to storm water runoff. We investigated sources and pathways of additives used in construction materials, i.e., biocides in facades' render as well as root protection products in bitumen membranes for rooftops. Under wet-weather conditions, the concentrations of diuron, terbutryn, carbendazim, irgarol 1051 (all from facades) and mecoprop in storm water and receiving water exceeded the predicted no-effect concentrations values and the Swiss water quality standard of 0.1 microg/L. Under laboratory conditions maximum concentrations of additives were in the range of a few milligrams and a few hundred micrograms per litre in runoff of facades and bitumen membranes. Runoff from aged materials shows approximately one to two orders of magnitude lower concentrations. Concentrations decreased also during individual runoff events. In storm water and receiving water the occurrence of additives did not follow the typical first flush model. This can be explained by the release lasting over the time of rainfall and the complexity of the drainage network. Beside the amounts used, the impact of construction materials containing hazardous additives on water quality is related clearly to the age of the buildings and the separated sewer network. The development of improved products regarding release of hazardous additives is the most efficient way of reducing the pollutant load from construction materials in storm water runoff.

  19. Leaching of additives from construction materials to urban storm water runoff

    DEFF Research Database (Denmark)

    Burkhardt, Mike; Zuleeg, S.; Boller, M.

    2011-01-01

    Urban water management requires further clarification about pollutants in storm water. Little is known about the release of organic additives used in construction materials and the impact of these compounds to storm water runoff. We investigated sources and pathways of additives used...... shows approximately one to two orders of magnitude lower concentrations. Concentrations decreased also during individual runoff events. In storm water and receiving water the occurrence of additives did not follow the typical first flush model. This can be explained by the release lasting over the time...

  20. Preparation and adsorption characteristics for heavy metals of active silicon adsorbent from leaching residue of lead-zinc tailings.

    Science.gov (United States)

    Lei, Chang; Yan, Bo; Chen, Tao; Xiao, Xian-Ming

    2018-05-19

    To comprehensively reuse the leaching residue obtained from lead-zinc tailings, an active silicon adsorbent (ASA) was prepared from leaching residue and studied as an adsorbent for copper(II), lead(II), zinc(II), and cadmium(II) in this paper. The ASA was prepared by roasting the leaching residue with either a Na 2 CO 3 /residue ratio of 0.6:1 at 700 °C for 1 h or a CaCO 3 /residue ratio of 0.8:1 at 800 °C for 1 h. Under these conditions, the available SiO 2 content of the ASA was more than 20%. The adsorption behaviors of the metal ions onto the ASA were investigated and the Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were used to analyze the adsorption isotherm. The result showed that the maximum adsorption capacities of copper(II), lead(II), cadmium(II), and zinc(II) calculated by the Langmuir model were 3.40, 2.83, 0.66, and 0.62 mmol g -1 , respectively. The FT-IR spectra of the ASA and the mean free adsorption energies indicated that ion exchange was the mechanism of copper(II), lead(II), and cadmium(II) adsorption and that chemical reaction was the mechanism of zinc(II) adsorption. These results provide a method for reusing the leaching residue obtained from lead-zinc tailings and show that the ASA is an effective adsorbent for heavy metal pollution remediation.

  1. Precipitation-induced runoff and leaching from milled peat mining mires by peat types : a comparative method for estimating the loading of water bodies during peat pruduction

    OpenAIRE

    Svahnbäck, Lasse

    2007-01-01

    Precipitation-induced runoff and leaching from milled peat mining mires by peat types: a comparative method for estimating the loading of water bodies during peat production. This research project in environmental geology has arisen out of an observed need to be able to predict more accurately the loading of watercourses with detrimental organic substances and nutrients from already existing and planned peat production areas, since the authorities capacity for insisting on such predicti...

  2. Selective recovery of molybdenum from spent HDS catalyst using oxidative soda ash leach/carbon adsorption method

    International Nuclear Information System (INIS)

    Park, Kyung Ho; Mohapatra, D.; Reddy, B. Ramachandra

    2006-01-01

    The petroleum refining industry makes extensive use of hydroprocessing catalysts. These catalysts contain environmentally critical and economically valuable metals such as Mo, V, Ni and Co. In the present study, a simple hydrometallurgical processing of spent hydrodesulphurization (HDS) catalyst for the recovery of molybdenum using sodium carbonate and hydrogen peroxide mixture was investigated. Recovery of molybdenum was largely dependent on the concentrations of Na 2 CO 3 and H 2 O 2 in the reaction medium, which in turn controls the pH of leach liquor and the presence of Al and Ni as impurities. Under the optimum leaching conditions (40 g L -1 Na 2 CO 3 , 6 vol.% H 2 O 2 , room temperature, 1 h) about 85% recovery of Mo was achieved. The leach liquor was processed by the carbon adsorption method, which selectively adsorbs Mo at pH around 0.75. Desorption of Mo was selective at 15 vol.% NH 4 OH. With a single stage contact, it was found possible to achieve >99%, adsorption and desorption efficiency. Using this method, recovery of molybdenum as MoO 3 product of 99.4% purity was achieved

  3. Fate of phosphorus fractions in an adsorptive-filter subject to intra- and inter-event runoff phenomena.

    Science.gov (United States)

    Berretta, Christian; Sansalone, John

    2012-07-30

    In-situ filtration of phosphorus (P) and particulate matter (PM) transported in runoff is increasingly implemented for urban source areas. While monitoring of filter response is commonly based on an event mean of total phosphorus (TP), this study examines the fate of specific P fractions through intra- and inter-event phenomena. This continuous filter monitoring program includes 15 wet weather loadings and the dry weather periods between these events. Aqueous P adsorption and PM-bound P (suspended, settleable and sediment) filtration phenomena are examined for runoff events from a landscaped carpark with biogenic loads in Gainesville (GNV), FL. Filter response is compared to a similar aluminum oxide Al-Ox modified media filter subject to anthropogenic loads from an urban paved source area in Baton Rouge (BTR), LA. Results for the GNV filter indicate that while intra-event settleable, sediment and dissolved P fractions are controlled by the filter, the suspended P fraction remained relatively mobile compared to the other P fractions. P adsorption is primarily influenced by intra-event flow rates, contact times, runoff volume, pH and by the inter-event chemistry of runoff stored in the filter. P effluent partitioning is dominated by the suspended PM as a consequence of effective adsorption by the filter. Inter-event phenomena generate decreasing redox with commensurate increases in alkalinity, conductivity as well as dissolved P as a consequence of re-partitioning. Dissolved P fate suggests that filters should be designed and managed to remain aerobic between wet weather events. For effective separation of suspended P and PM fractions by passive filters with low driving head, sustainability of performance, including head loss {<3 kPa}, requires upstream volumetric attenuation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Reducing phosphorus runoff and leaching from poultry litter with alum: Twenty-year small plot and paired-watershed studies

    Science.gov (United States)

    Treating poultry litter with alum is a best management practice (BMP) for lowering ammonia (NH3) emissions and phosphorus (P) runoff losses. The objective of this study was to evaluate the long-term (20 year) effects of alum-treated and untreated poultry litter applications on P availability, leachi...

  5. Design and development of green roof substrate to improve runoff water quality: plant growth experiments and adsorption.

    Science.gov (United States)

    Vijayaraghavan, K; Raja, Franklin D

    2014-10-15

    Many studies worldwide have investigated the potential benefits achievable by transforming brown roofs of buildings to green roofs. However, little literature examined the runoff quality/sorption ability of green roofs. As the green roof substrate is the main component to alter the quality of runoff, this investigation raises the possibility of using a mixture of low-cost inorganic materials to develop a green roof substrate. The tested materials include exfoliated vermiculite, expanded perlite, crushed brick and sand along with organic component (coco-peat). Detailed physical and chemical analyses revealed that each of these materials possesses different characteristics and hence a mix of these materials was desirable to develop an optimal green roof substrate. Using factorial design, 18 different substrate mixes were prepared and detailed examination indicated that mix-12 exhibited desirable characteristics of green roof substrate with low bulk density (431 kg/m(3)), high water holding capacity (39.4%), air filled porosity (19.5%), and hydraulic conductivity (4570 mm/h). The substrate mix also provided maximum support to Portulaca grandiflora (380% total biomass increment) over one month of growth. To explore the leaching characteristics and sorption capacity of developed green roof substrate, a down-flow packed column arrangement was employed. High conductivity and total dissolved solids along with light metal ions (Na, K, Ca and Mg) were observed in the leachates during initial stages of column operation; however the concentration of ions ceased during the final stages of operation (600 min). Experiments with metal-spiked deionized water revealed that green roof substrate possess high sorption capacity towards various heavy metal ions (Al, Fe, Cr, Cu, Ni, Pb, Zn and Cd). Thus the developed growth substrate possesses desirable characteristics for green roofs along with high sorption capacity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Interpretation of certain spectroscopic peculiarities of rare earth activators in liquifying glass based on adsorption study of their leaching products

    International Nuclear Information System (INIS)

    Burkat, T.M.; Galant, E.I.; Dobychin, D.P.; Zinyakova, V.M.; Rejshakhrit, A.L.; Tolstoj, M.N.

    1977-01-01

    A sorption method was employed to investigate the porous products from the leaching of DV-1 glasses containing various activators and to study spectral properties of segregating glasses. The volume of pores formed in leaching and the distribution of their radii were studied in glasses subjected to various thermal treatments. The relationship was investigated of the kinetics of growth of the size of the inhomogeneity areas and the presence of activators. It is found that those segregating transformations in the glass, which influence the interaction of ions of different earth elements, are related to the formation of inhomogeneity areas of radii of more than 8 and less than 50 A

  7. Tebuthiuron Movement via Leaching and Runoff from Grazed Vertisol and Alfisol Soils in the Brigalow Belt Bioregion of Central Queensland, Australia.

    Science.gov (United States)

    Thornton, Craig M; Elledge, Amanda E

    2016-05-25

    Tebuthiuron is one of five priority herbicides identified as a water pollutant entering the Great Barrier Reef. A review of tebuthiuron research in Australia found 13 papers, 6 of which focused on water quality at the basin scale (>10,000 km(2)) with little focus on process understanding. This study examined the movement of tebuthiuron in soil and runoff at the plot (1.7 m(2)) and small catchment (12.7 ha) scales. The greatest concentration and mass in soil occurred from 0 to 0.05 m depth 30-57 days after application. Concentrations at all depths tended to decrease after 55-104 days. Runoff at the small catchment scale contained high concentrations of tebuthiuron (average = 103 μg/L) 100 days after application, being 0.05% of the amount applied. Tebuthiuron concentrations in runoff declined over time with the majority of the chemical in the dissolved phase.

  8. Adsorção e lixiviação de boro em Latossolo Vermelho-Amarelo Boron adsorption and leaching in a Brazilian Oxisol

    Directory of Open Access Journals (Sweden)

    Ciro Antonio Rosolem

    2007-10-01

    Full Text Available O objetivo deste trabalho foi avaliar a adsorção e a lixiviação do boro em Latossolo Vermelho-Amarelo distrófico, cultivado com soja, em conseqüência das doses de boro e da calagem. Foram analisadas amostras de um solo do Estado do Mato Grosso, cultivado com soja durante três anos, com doses de 0, 1,5, 3, 4,5, 6, 7,5 e 9 Mg ha-1 de calcário, e 0, 1, 3, 5, 7 e 10 kg ha-1 de boro, aplicados no primeiro ano de cultivo. Foram determinadas isotermas de adsorção de boro em função da calagem e do tempo de cultivo, assim como a lixiviação em função da calagem e da adubação boratada. No caso da calagem, mesmo com doses relativamente altas de calcário, a adsorção de boro pelo solo é muito alta apenas no ano de aplicação do corretivo, e diminui significativamente com o tempo. No entanto, a lixiviação de boro guarda estreita relação com o teor do nutriente no solo e com a dose do nutriente que é aplicada, mas é pouco influenciada pela calagem.The objective of this work was to evaluate soil boron dynamics in a Typic Hapludox cropped with soybean for three years, as affected by boron rates and liming. Soil samples were taken during three years from a field experiment with lime rates of 0, 1.5, 3, 4.5, 6, 7.5 and 9 Mg ha-1 and boron rates of 0, 1, 3, 5, 7 and 10 kg ha-1. Boron adsorption isotherms as affected by liming and time under cropping were determined. Boron leaching, as affected by boron fertilization and liming was also evaluated. When lime was applied, even at high rates, soil boron adsorption was very high only in the first year, and decreased with time. Boron leaching, though not affected by liming, is strongly related to soil boron contents and boron fertilization.

  9. Adsorption

    Directory of Open Access Journals (Sweden)

    Sushmita Banerjee

    2017-05-01

    Full Text Available Application of saw dust for the removal of an anionic dye, tartrazine, from aqueous solutions has been investigated. The experiments were carried out in batch mode. Effect of the parameters such as pH, initial dye concentration and temperature on the removal of the dye was studied. Equilibrium was achieved in 70 min. Maximum adsorption of dye was achieved at pH 3. Removal percent was found to be dependent on the initial concentration of dye solution, and maximum removal was found to be 97% at 1 mg/L of tartrazine. The removal increases from 71% to 97% when the initial concentration of dye solution decreases from 15 mg/L to 1 mg/L. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. The (Langmuir adsorption capacity of the adsorbent is found to be 4.71 mg/g at 318 K. Kinetic modeling of the process of removal was carried out and the process of removal was found to follow a pseudo second order model and the value of rate constant for adsorption process was calculated as 2.7 × 10−3 g mg−1 min−1 at 318 K. The thermodynamic parameters such as change in free energy (ΔG°, enthalpy (ΔH° and entropy (ΔS° were determined and the negative values of ΔG° indicated that the process of removal was spontaneous at all values of temperatures. Further, the values of ΔH° indicated the endothermic nature of the process of removal.

  10. Precipitation-induced runoff and leaching from milled peat mining mires by peat types: A comparative method for estimating the loading of water bodies during peat production

    Energy Technology Data Exchange (ETDEWEB)

    Svahnbaeck, L.

    2007-07-01

    characteristics of the peat in a mire, although earlier observations have indicated that watercourse loading from peat production can vary greatly and it has been suggested that differences in peat properties may be of significance in this. Sprinkling is used here in combination with simulations of conditions in a milled peat production area to determine the influence of the physical and chemical properties of milled peats in production mires on surface runoff into the drainage ditches and the concentrations of material in the runoff water. Sprinkling and extraction experiments were carried out on 25 samples of milled Carex (C) and Sphagnum (S) peat of humification grades H 2.5-8.5 with moisture content in the range 23.4-89% on commencement of the first sprinkling, which was followed by a second sprinkling 24 hours later. The water retention capacity of the peat was best, and surface runoff lowest, with Sphagnum and Carex peat samples of humification grades H 2.5-6 in the moisture content class 56-75%. On account of the hydrophobicity of dry peat, runoff increased in a fairly regular manner with drying of the sample from 55% to 24-30%. Runoff from the samples with an original moisture content over 55% increased by 63% in the second round of sprinkling relative to the first, as they had practically reached saturation point on the first occasion, while those with an original moisture content below 55% retained their high runoff in the second round, due to continued hydrophobicity. The well-humified samples (H 6.5-8.5) with a moisture content over 80% showed a low water retention capacity and high runoff in both rounds of sprinkling. Once data are available on the area of the mire, its peat depth, peat types and their degrees of humification, dry matter content, calorific value and corresponding energy content, it is possible to produce mutually comparable estimates for individual mires with respect to the annual loading of the drainage ditch system and the surrounding watercourse

  11. Runoff erosion

    OpenAIRE

    Evelpidou, Niki (Ed.); Cordier, Stephane (Ed.); Merino, Agustin (Ed.); Figueiredo, Tomás de (Ed.); Centeri, Csaba (Ed.)

    2013-01-01

    Table of Contents PART I – THEORY OF RUNOFF EROSION CHAPTER 1 - RUNOFF EROSION – THE MECHANISMS CHAPTER 2 - LARGE SCALE APPROACHES OF RUNOFF EROSION CHAPTER 3 - MEASURING PRESENT RUNOFF EROSION CHAPTER 4 - MODELLING RUNOFF EROSION CHAPTER 5 - RUNOFF EROSION AND HUMAN SOCIETIES: THE INFLUENCE OF LAND USE AND MANAGEMENT PRACTICES ON SOIL EROSION PART II - CASE STUDIES CASE STUDIES – INTRODUCTION: RUNOFF EROSION IN MEDITERRANEAN AREA CASE STUDY 1: Soil Erosion Risk...

  12. Numerical simulation of vertical infiltration for leaching fluid in situ

    International Nuclear Information System (INIS)

    Li Jinxuan; Shi Weijun; Zhang Weimin

    1998-01-01

    Based on the analysis of movement law of leaching fluid in breaking and leaching experiment in situ, the movement of leaching fluid can be divided into two main stages in the leaching process in situ: Vertical Infiltration in unsaturation zone and horizontal runoff in saturation zone. The corresponding mathematics models are sep up, and the process of vertical infiltration of leaching fluid is numerically simulated

  13. Adsorption of Rh(III) complexes from chloride solutions obtained by leaching chlorinated spent automotive catalysts on ion-exchange resin Diaion WA21J

    International Nuclear Information System (INIS)

    Shen Shaobo; Pan Tonglin; Liu Xinqiang; Yuan Lei; Wang Jinchao; Zhang Yongjian; Guo Zhanchen

    2010-01-01

    It was found that Rh, Pd and Pt contained in the spent ceramic automotive catalysts could be effectively extracted by dry chlorination with chlorine. In order to concentrate Rh(III) ions contained in the chloride solutions obtained, thermodynamic and kinetics studies for adsorption of Rh(III) complexes from the chloride solutions on an anionic exchange resin Diaion WA21J were carried out. Rh, Pd, Pt, Al, Fe, Si, Zn and Pb from the chloride solution could be adsorbed on the resin. The distribution coefficients (K d ) of Rh(III) decreased with the increase in initial Rh(III) concentration or in adsorption temperature. The isothermal adsorption of Rh(III) was found to fit Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich models under the adsorption conditions. The maximum monolayer adsorption capacities Q max based on Langmuir adsorption isotherms were 6.39, 6.61 and 5.81 mg/g for temperatures 18, 28 and 40 deg. C, respectively. The apparent adsorption energy of Rh was about -7.6 kJ/mol and thus Rh(III) adsorption was a physical type. The experimental data obtained could be better simulated by pseudo-first-order kinetic model and the activation energy obtained was 6.54 J/mol. The adsorption rate of Rh(III) was controlled by intraparticle diffusion in most of time of adsorption process.

  14. Adsorption by and artificial release of zinc and lead from porous concrete for recycling of adsorbed zinc and lead and of porous concrete to reduce urban non-point heavy metal runoff.

    Science.gov (United States)

    Harada, Shigeki; Yanbe, Miyu

    2018-04-01

    This report describes the use of porous concrete at the bottom of a sewage trap to prevent runoff of non-point heavy metals into receiving waters, and, secondarily, to reduce total runoff volume during heavy rains in urbanized areas while simultaneously increasing the recharge volume of heavy-metal-free water into underground aquifers. This idea has the advantage of preventing clogging, which is fundamentally very important when using pervious materials. During actual field experiments, two important parameters were identified: maximum adsorption weight of lead and zinc by the volume of porous concrete, and heavy metal recovery rate by artificial acidification after adsorption. To understand the effect of ambient heavy metal concentration, a simple mixing system was used to adjust the concentrations of lead and zinc solutions. The concrete blocks used had been prepared for a previous study by Harada & Komuro (2010). The results showed that maximum adsorption depended on the ambient concentration, expressed as the linear isothermal theory, and that recovery depended on the final pH value (0.5 or 0.0). The dependence on pH is very important for recycling the porous concrete. A pH of 0.5 is important for recycling both heavy metals, especially zinc, (8.0-22.1% of lead and 42-74% of zinc) and porous concrete because porous concrete has not been heavily damaged by acid. However, at a pH of 0.0, the heavy metals could be recovered: 30-60% of the lead and 75-125% of the zinc. At a higher pH, such as 2.0, no release of heavy metals occurred, indicating the safety to the environment of using porous concrete, because the lowest recorded pH of rainfall in Japan is. 4.0. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Bacterial Leaching

    Indian Academy of Sciences (India)

    and studies microbial biotechnology and ... foundation for subsequent research into the role of microorgan- ... are more readily accesible, for example those in solution, rather .... Vat leaching as currently applied to oxide ores involves the.

  16. Leaching mechanisms

    International Nuclear Information System (INIS)

    Dougherty, D.R.; Colombo, P.

    1984-01-01

    Sufficient data are lacking to provide a basis for adequately assessing the long term leaching behavior of solidified low level radioactive waste forms in their disposal environment. Although the release of radioactivity from a waste form to an aqueous environment is recognized to be due to one or more mechanisms such as diffusion, dissolution, corrosion or ion exchange, the leaching mechanisms and the factors which control the leaching behavior of waste forms are not fully understood. This study will determine the prevailing mechanisms for a variety of selected LLW solidification agents which are being considered for use by defense and commercial generators and which will cover the broadest possible number of mechanisms. The investigation will proceed by the postulation of mathematical models representative of the prevailing mechanism(s) and the use of statistically designed experiments to test the actual leaching behavior of laborattory samples against the postulated representations. Maximum use of existing leach data in the literature will be made by incorporating literature results into a computerized data base along with the experimental results generated in this task

  17. Leaching process

    International Nuclear Information System (INIS)

    Heinen, H.J.; McClelland, G.E.; Lindstrom, R.E.

    1982-01-01

    A gold and uranium ore is heap leached in accordance with the process comprising initial agglomeration of fines in the feed by means of a binding agent and cyanide solution. The lixiviant comprises a compatible mixture of sodium cyanide and sodium bicarbonate

  18. Leaching process

    Energy Technology Data Exchange (ETDEWEB)

    Heinen, H J; McClelland, G E; Lindstrom, R E

    1982-10-18

    A gold and uranium ore is heap leached in accordance with the process comprising initial agglomeration of fines in the feed by means of a binding agent and cyanide solution. The lixiviant comprises a compatible mixture of sodium cyanide and sodium bicarbonate.

  19. Physicochemical conditions and properties of particles in urban runoff and rivers: Implications for runoff pollution.

    Science.gov (United States)

    Wang, Qian; Zhang, Qionghua; Wu, Yaketon; Wang, Xiaochang C

    2017-04-01

    In this study, to gain an improved understanding of the fate and fractionation of particle-bound pollutants, we evaluated the physicochemical conditions and the properties of particles in rainwater, urban runoff, and rivers of Yixing, a city with a large drainage density in the Taihu Lake Basin, China. Road runoff and river samples were collected during the wet and dry seasons in 2015 and 2016. There were significant differences between the physicochemical conditions (pH, oxidation-reduction potential (ORP), and electroconductivity (EC)) of rainwater, runoff, and rivers. The lowest pH and highest ORP values of rainwater provide the optimal conditions for leaching of particle-bound pollutants such as heavy metals. The differences in the physicochemical conditions of the runoff and rivers may contribute to the redistribution of pollutants between particulate and dissolved phases after runoff is discharged into waterways. Runoff and river particles were mainly composed of silt and clay (runoff particles contained a higher proportion of nano-scale particles (runoff pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Refractory concentrate gold leaching: Cyanide vs. bromine

    Science.gov (United States)

    Dadgar, Ahmad

    1989-12-01

    Gold extraction, recovery and economics for two refractory concentrates were investigated using cyanide and bromine reagents. Gold extractions for cyanide leaching (24-48 hours) and bromine leaching (six hours) were the same and ranged from 94 to 96%. Gold recoveries from bromine pregnant solutions using carbon adsorption, ion exchange, solvent extraction, and zinc and aluminum precipitation methods were better than 99.9%. A preliminary economic analysis indicates that chemical costs for cyanidation and bromine process are 11.70 and 11.60 respectively, per tonne of calcine processed.

  1. Leaching of Glyphosate and Aminomethylphosphonic Acid from an Agricultural Field over a Twelve-Year Period

    DEFF Research Database (Denmark)

    Norgaard, Trine; Moldrup, Per; Ferré, Ty P A

    2014-01-01

    content at the time of application and the level of the groundwater table relative to the drain depth was essential for whether solutes were detected in the drainage runoff. We present a leaching risk chart to illustrate the dependence of glyphosate, AMPA, and soil particle leaching based on precipitation......, and particles. Glyphosate and AMPA leaching were highly event driven, controlled by the time and intensity of the first precipitation event after glyphosate application. A high similarity in time-accumulated curves for drainage and leached pesticide masses suggests near-constant drainage and leaching rates...

  2. Leaching of organic carbon and nitrogen from peatland-dominated catchments

    International Nuclear Information System (INIS)

    Kortelainen, P.

    1992-01-01

    The area of 13 study catchments is 2.5-56-3 km 2 and 37-87 % of the catchments is covered by peatlands. Ditching intensities varied from 0 to 100 %. Median total organic carbon (TOC) in runoff waters from the catchments was 10-30 mg/l - 1 and median nitrogen (N tot ) 380-1000 μg/1 -1 . The annual leaching of TOC and Ntot was calculated for five catchments for which daily runoff data was available. The range for mean annual leaching of TOC and N tot from the catchments was 4700-7300 kg/km 2 a and 190-250 kg/km -2 a -1 , respectively. The variation between different years was high and annual leaching was closely related to annual runoff. The regional variation in the leaching of TOC and N tot was small compared to the annual variation

  3. Biocide leaching during field experiments on treated articles.

    Science.gov (United States)

    Schoknecht, Ute; Mathies, Helena; Wegner, Robby

    2016-01-01

    Biocidal products can be sources of active substances in surface waters caused by weathering of treated articles. Marketing and use of biocidal products can be limited according to the European Biocidal Products Regulation if unacceptable risks to the environment are expected. Leaching of active substances from treated articles was observed in field experiments to obtain information on leaching processes and investigate the suitability of a proposed test method. Leaching under weathering conditions proceeds discontinuously and tends to decrease with duration of exposure. It does not only mainly depend on the availability of water but is also controlled by transport processes within the materials and stability of the observed substances. Runoff amount proved to be a suitable basis to compare results from different experiments. Concentrations of substances are higher in runoff collected from vertical surfaces compared to horizontal ones, whereas the leached amounts per surface area are higher from horizontal surfaces. Gaps in mass balances indicate that additional processes such as degradation and evaporation may be relevant to the fate of active substances in treated articles. Leached amounts of substances were considerably higher when the materials were exposed to intermittent water contact under laboratory conditions as compared to weathering of vertically exposed surfaces. Experiences from the field experiments were used to define parameters of a procedure that is now provided to fulfil the requirements of the Biocidal Products Regulation. The experiments confirmed that the amount of water which is in contact with exposed surfaces is the crucial parameter determining leaching of substances.

  4. Heap leaching for uranium

    International Nuclear Information System (INIS)

    1988-01-01

    Denison Mines Ltd. is using two bacterial leaching processes to combat the high cost of extracting uranium from low grade ore in thin reefs. Both processes use thiobacillus ferro-oxidans, a bacterium that employs the oxidation of ferrous iron and sulphur as its source of energy for growth. The first method is flood leaching, in which ore is subjected to successive flood, drain and rest cycles. The second, trickle leaching, uses sprinklers to douse the broken muck continuously with leaching solution. In areas where grades are too low to justify the expense of hauling the ore to the surface, the company is using this biological process underground to recover uranium. In 1987 Denison recovered 840 000 lb of uranium through bacterial heap leaching. It plans to have biological in-place leaching contribute 25% of the total uranium production by 1990. (fig.)

  5. Soils - Potential Runoff

    Data.gov (United States)

    Kansas Data Access and Support Center — This digital spatial data set provides information on the spatial distribution of potential runoff-contributing areas in Kansas. Potential runoff-contributing areas...

  6. Leaching of FGD Byproducts Using a CSTX

    Energy Technology Data Exchange (ETDEWEB)

    Kairies, C.L.; Schroeder, K.T.; Cardone, C.R.

    2005-09-01

    Leaching studies of coal utilization byproducts (CUB) are often performed to determine the compatibility of the material in a particular end-use or disposal environment. Typically, these studies are conducted using either a batch or a fixed-bed column technique. Fixed-bed columns offer the advantage of a continuous flow of effluent that provides elution profiles with changing elution volume and pH. Unfortunately, clogs can form in fixed-bed leaching columns, either because of cementitious properties of the material itself, such as is seen for fluidized bed combustion (FBC) fly ash, or because of precipitate formation, such as can occur when a high-calcium ash is subjected to sulfate-containing leachates. Also, very fine-grained materials, such as gypsum, do not provide sufficient permeability for study in a fixed-bed column. A continuous, stirred-tank extractor (CSTX) is being used as an alternative technique that can provide the elution profile of column leaching but without the low permeability problems. The CSTX has been successfully employed in the leaching of flue gas desulfurization products that would not be sufficiently permeable under traditional column leaching conditions. The results indicate that the leaching behavior depends on a number of factors, including (but not limited to) solubility and neutralization capacity of the mineral phases present, sorption properties of these phases, behavior of the solubilized material in the tank, and the type of species in solution. In addition, leaching to near-exhaustion of a wallboard produced from FGD gypsum has allowed the isolation of a highly adsorptive phase. This phase appears to be present in at least some FGD gypsums and accounts for the immobilization of trace metals such as arsenic, cobalt, lead, and mercury.

  7. Comparative Study on the Leaching Characteristics of Industrial Sludge and Fly Ash using KSLP and TCLP Techniques

    International Nuclear Information System (INIS)

    Lee, B.K.; Hwang, H.W.

    2010-01-01

    Leaching characteristics of industrial sludge and fly ash using Korean Standard Leaching Procedure (KSLP) and Toxicity Characteristics Leaching Procedure (TCLP) were studied. Possibilities of re-adsorption of heavy metal ions on the surface of sludge and ash during the course of leaching were also investigated. KSLP looked relatively more aggressive than the TCLP in leaching heavy metal ions. Concentrations of metal ions leached in both the methods, however, were found very low in comparison to the concentration of ions present in the original samples. In case of sludge, heavy metal ions showed relatively high rate of leaching at fourth and fifth stages of sequential extraction while ash showed high rate of leaching at the first three stages of extraction. Some of the concentrations of heavy metal ions leached out in the tests also found to be adsorbed on the surface of sludge and ash. Heavy metal ions present in high concentrations in the sample showed lower rate of adsorption than their leaching rate. No distinct difference in the results of KSLP and TCLP was observed. However, variations in the leaching results could be due to the different nature of hazardous waste and leaching conditions. More information like kinetics of leaching, mineralogical characteristics of waste and site characteristics of landfill were required to predict more accurate leaching behavior of ions in natural conditions. (author)

  8. Nitrate Leaching Management

    Science.gov (United States)

    Nitrate (NO3) leaching is a significant nitrogen (N) loss process for agriculture that must be managed to minimize NO3 enrichment of groundwater and surface waters. Managing NO3 leaching should involve the application of basic principles of understanding the site’s hydrologic cycle, avoiding excess ...

  9. Nitrate leaching index

    Science.gov (United States)

    The Nitrate Leaching Index is a rapid assessment tool that evaluates nitrate (NO3) leaching potential based on basic soil and climate information. It is the basis for many nutrient management planning efforts, but it has considerable limitations because of : 1) an oversimplification of the processes...

  10. Immobilized waste leaching

    International Nuclear Information System (INIS)

    Suarez, A.A.

    1989-01-01

    The main mechanism by which the immobilized radioactive materials can return to biosphere is the leaching due to the intrusion of water into the repositories. Some mathematical models and experiments utilized to evaluate the leaching rates in different immobilization matrices are described. (author) [pt

  11. In situ leaching of uranium

    International Nuclear Information System (INIS)

    Martin, B.

    1980-01-01

    A process is described for the in-situ leaching of uranium-containing ores employing an acidic leach liquor containing peroxymonosulphuric acid. Preferably, additionally, sulphuric acid is present in the leach liquor. (author)

  12. Chlorination leaching of cadmium

    International Nuclear Information System (INIS)

    Lach, E.; Pajak, I.; Bojanowska, A.

    1978-01-01

    The results of the investigations on chlorination leaching of cadmium from dust coming from dry dust collector of sinter belt, that is leaching with water saturated with gaseous chlorine and leaching with solutions of ammonium chloride and sodium chloride were given. The optimum conditions for these processes were established. It was found, that the method of leaching in the presence of gaseous chlorine is more effective, as it allows to report into the solution over 90% cadmium contained in dust. Owing to technical difficulties, environmental protection and safety conditions more advantageous seems to be the use as leaching agent of the ammonium chloride solutions. When applying 20% NH 4 Cl and temperature of 60 0 C, the time of 2 hours and the ratio of solid to liquid of 1:5, 70% cadmium contained in the dust can be reported into the solution. (auth.)

  13. The influence of dual-substrate-layer extensive green roofs on rainwater runoff quantity and quality.

    Science.gov (United States)

    Wang, Xiaoou; Tian, Yimei; Zhao, Xinhua

    2017-08-15

    This study investigates the ability of dual-substrate-layer extensive green roofs to retain rainwater and reduce pollutant leaching. The substrates in dual-substrate-layer green roofs consist of an upper organic nutrition layer for plant growth and a lower inorganic adsorption layer for water retention and pollutant reduction. One traditional single-substrate-layer extensive green roof was built for comparison with dual-substrate-layer green roofs. During the experimental period, dual-substrate-layer green roofs supported better natural vegetation growth, with coverage exceeding 90%, while the coverage in single-substrate-layer green roof was over 80%. Based on the average retention value of the total rainfall for four types of simulated rains (the total rainfall depth (mm) was 43.2, 54.6, 76.2 and 86.4, respectively), the dual-substrate-layer green roofs, which used the mixture of activated charcoal with perlite and vermiculite as the adsorption substrate, possessed better rainfall retention performance (65.9% and 55.4%) than the single-substrate-layer green roof (52.5%). All of the dual-substrate-layer green roofs appeared to be sinks for organics, heavy metals and all forms of nitrogen in all cases, while acted as sources of phosphorus contaminants in the case of heavy rains. In consideration of the factors of water retention, pollution reduction and service life of the green roof, a mixture of activated charcoal and/or pumice with perlite and vermiculite is recommended as the adsorption substrate. The green roofs were able to mitigate mild acid rain, raising the pH from approximately 5.6 in rainfall to 6.5-7.6 in green roof runoff. No signs of a first flush effect for phosphate, total phosphorus, ammonia nitrogen, nitrate nitrogen, total nitrogen, organics, zinc, lead, chromium, manganese, copper, pH or turbidity were found in the green roof runoff. Cost analysis further proved the practicability of dual-substrate-layer green roofs in retaining rainwater, and

  14. Bicarbonate leaching of uranium

    International Nuclear Information System (INIS)

    Mason, C.

    1998-01-01

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented

  15. Bicarbonate leaching of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Mason, C.

    1998-12-31

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented.

  16. Leach testing of waste forms: interrelationship of ISO and MCC type tests

    International Nuclear Information System (INIS)

    Oversby, V.M.

    1982-01-01

    Leach testing experiments were conducted on SYNROC-D material to examine the parameters which affect leaching results and to measure the activation energy for leaching of elements from SYNROC-D. Measured leach rates were found to be controlled by precipitation of insoluble phases for those tests where the sample surface area to volume of leachant (SA/V) multiplied by leaching time (t) exceeded 0.3 cm -1 d for leach tests at 90 0 C. In these cases the apparent activation energy for leaching was approximately 10 kcal/mole based on Na and Si data. For leach tests at 90 0 C with (Sa/V)(t) less than 0.2 cm -1 d, the activation energy for Na and Si dissolution was 18.5 kcal/mole for sample S29 and 14.5 kcal/mole for sample LSO4. The effect of sample geometry was investigated by leaching a series of crushed samples of different grain size. The results support the view that geometric surface area should be used in leach rate calculations rather than gas adsorption BET surface area. Comparison of results on S29 leaching of crushed samples and monoliths show that data from MCC-1 and ISO type leach tests may be directly compared when the data are examined at constant (SA/V)(t). 5 figures, 13 tables

  17. Glass leaching performance

    International Nuclear Information System (INIS)

    Chick, L.A.; Turcotte, R.P.

    1983-05-01

    Current understanding of the leaching performance of high-level nuclear waste (HLW) glass is summarized. The empirical model of waste glass leaching behavior developed shows that at high water flow rates the glass leach rate is kinetically limited to a maximum value. At intermediate water flow rates, leaching is limited by the solution concentration of silica and decreases with decreasing water flow rates. Release of soluble elements is controlled by silica dissolution because silica forms the binding network of the glass. At low water flow rates, mass loss rates reach values controlled by formation rates of alteration minerals, or by diffusion of dissolution products through essentially stagnant water. The parameters reviewed with respect to their quantifiable influence on leaching behavior include temperature, pH, leachant composition, glass composition, thermal history, and radiation. Of these, temperature is most important since the rate of mass loss approximately doubles with each 10 0 C increase in dilute solutions. The pH has small effects within the 4 to 10 range. The chemical composition of the leachant is most important with regard to its influence on alteration product formation. Glass composition exhibits the largest effects at high flow rates where improved glasses leach from ten to thirty times slower than glass 76 to 68. The effects of the thermal history (devitrification) of the glass are not likely to be significant. Radiation effects are important primarily in that radiolysis can potentially drive pH values to less than 4. Radiation damage to the glass causes insignificant changes in leaching performance

  18. Temporal Patterns of Glyphosate Leaching at a Loamy Agricultural Field in Denmark

    DEFF Research Database (Denmark)

    Nørgaard, Trine; Møldrup, Per; Olsen, Preben

    2013-01-01

    applications in combination with the effect of precipitation events, drain water runoff, soil water content at 25 cm soil depth, management, and particle leaching patterns, and compares this with monitored field-scale glyphosate and AMPA leaching to a tile drainage system. Preliminary findings indicate...... that there is an accumulation of glyphosate and AMPA in the soil after the successive applications of glyphosate, as the level of the peaking concentrations right after applications increases. Furthermore, large precipitation events with subsequent high drain water runoff together with management, especially plowing...

  19. Diffuse emission and control of copper in urban surface runoff.

    Science.gov (United States)

    Boller, M A; Steiner, M

    2002-01-01

    Copper washed off from roofs and roads is considered to be a major contribution to diffuse copper pollution of urban environments. In order to guarantee sustainable protection of soils and water, the long-term strategy is to avoid or replace copper containing materials on roofs and fagades. Until achievement of this goal, a special adsorber system is suggested to control the diffuse copper fluxes by retention of copper by a mixture of granulated iron-hydroxide (GEH) and calcium carbonate. Since future stormwater runoff concepts are based on decentralised runoff infiltration into the underground, solutions are proposed which provide for copper retention in infiltration sites using GEH adsorption layers. The example of a large copper façade of which the runoff is treated in an adsorption trench reveals the first full-scale data on façade runoff and adsorber performance. During the first year of investigation average façade runoff concentrations in the range of 1-10 mg Cu/l are reduced by 96-99% in the adsorption ditch.

  20. Measurement of leached hulls

    International Nuclear Information System (INIS)

    Reilly, T.D.

    1979-07-01

    Leached hulls are the short lengths of fuel rod cladding and fuel element hardware which constitute a major waste product of a reprocessing plant employing a chop-and-leach head-end process. The small, undissolved fuel residue (0.1 to 1.0% of original fuel content) which is discarded with this waste must be measured for safeguards, material accountability, and process control reasons. This report gives a critical analysis of hull measurement techniques involving the analysis of fission product gamma rays, spontaneous fission neutrons from curium, and delayed neutron activation. Major emphasis is given to the measurement of 2186-keV gamma rays from 144 Ce-- 144 Pr. A detailed description of typical leached hull characteristics is presented at the beginning of the report. An extensive review of experience gained from existing hull measurement systems in the United Kingdom, France, Japan, Germany, Italy, and the United States is presented

  1. Runoff from armored slopes

    International Nuclear Information System (INIS)

    Codell, R.B.

    1986-01-01

    Models exist for calculating overland flow on hillsides but no models have been found which explicitly deal with runoff from armored slopes. Flow on armored slopes differs from overland flow, because substantial flow occurs beneath the surface of the rock layer at low runnoff, and both above and below the surface for high runoff. In addition to the lack of a suitable model, no estimates of the PMP exist for such small areas and for very short durations. This paper develops a model for calculating runoff from armored embankments. The model considers the effect of slope, drainage area and ''flow concentration'' caused by irregular grading or slumping. A rainfall-duration curve based on the PMP is presented which is suitable for very small drainage areas. The development of the runoff model and rainfall-duration curve is presented below, along with a demonstration of the model on the design of a hypothetical tailings embankment

  2. Functional nanostructured materials for stormwater runoff treatment

    DEFF Research Database (Denmark)

    Ko, Dongah

    Numerous heavy metal removal practices for stormwater runoff have been studied and applied; however, there is still room for improvement. Among these practices, adsorption has proven to be the most efficient way of removing heavy metals. Commonly used adsorbents have an innate sorption capacity...... in relation to high concentrations of heavy metal ions, but if they are to be used for stormwater runoff, high affinity with rapid sorption kinetics for low concentrations of heavy metals is necessary. Therefore, in this study, new types of functional nanostructured polymer sorbents for effective heavy metal...... removal from stormwater are suggested. First, comparison studies of several existing polymer sorbents were conducted, to find decisive functional groups for removing heavy metals from the solution. To enhance the sorption kinetics and affinity of polymer sorbents in the presence of competing ions, sulphur...

  3. Accelerated leach test development program

    International Nuclear Information System (INIS)

    Fuhrmann, M.; Pietrzak, R.F.; Heiser, J.; Franz, E.M.; Colombo, P.

    1990-11-01

    In FY 1989, a draft accelerated leach test for solidified waste was written. Combined test conditions that accelerate leaching were validated through experimental and modeling efforts. A computer program was developed that calculates test results and models leaching mechanisms. This program allows the user to determine if diffusion controls leaching and, if this is the case, to make projections of releases. Leaching mechanisms other than diffusion (diffusion plus source term partitioning and solubility limited leaching) are included in the program is indicators of other processes that may control leaching. Leach test data are presented and modeling results are discussed for laboratory scale waste forms composed of portland cement containing sodium sulfate salt, portland cement containing incinerator ash, and vinyl ester-styrene containing sodium sulfate. 16 refs., 38 figs., 5 tabs

  4. Urananite leaching: literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Grisham, G.F.; Bryant, E.A.; Williams, K.E.

    1979-04-01

    A literature survey was undertaken to provide background materials for a series of experiments involving the interaction of spent uranium dioxide fuel with various environments. Notes and references pertaining to the basic properties of UO/sub 2/ as produced and after reactor exposure are presented. The use of computerized literature searches is illustrated with specific topics related to leaching experiments. 57 references.

  5. Urananite leaching: literature survey

    International Nuclear Information System (INIS)

    Grisham, G.F.; Bryant, E.A.; Williams, K.E.

    1979-04-01

    A literature survey was undertaken to provide background materials for a series of experiments involving the interaction of spent uranium dioxide fuel with various environments. Notes and references pertaining to the basic properties of UO 2 as produced and after reactor exposure are presented. The use of computerized literature searches is illustrated with specific topics related to leaching experiments. 57 references

  6. Mapping ground water vulnerability to pesticide leaching with a process-based metamodel of EuroPEARL

    NARCIS (Netherlands)

    Tiktak, A.; Boesten, J.J.T.I.; Linden, van der A.M.A.; Vanclooster, M.

    2006-01-01

    To support EU policy, indicators of pesticide leaching at the European level are required. For this reason, a metamodel of the spatially distributed European pesticide leaching model EuroPEARL was developed. EuroPEARL considers transient flow and solute transport and assumes Freundlich adsorption,

  7. In-situ uranium leaching

    International Nuclear Information System (INIS)

    Dotson, B.J.

    1986-01-01

    This invention provides a method for improving the recovery of mineral values from ore bodies subjected to in-situ leaching by controlling the flow behaviour of the leaching solution. In particular, the invention relates to an in-situ leaching operation employing a foam for mobility control of the leaching solution. A foam bank is either introduced into the ore bed or developed in-situ in the ore bed. The foam then becomes a diverting agent forcing the leaching fluid through the previously non-contacted regions of the deposit

  8. Fluometuron and pendimethalin runoff from strip and conventionally tilled cotton in the southern atlantic coastal plain.

    Science.gov (United States)

    Potter, Thomas L; Truman, Clint C; Bosch, David D; Bednarz, Craig

    2004-01-01

    In the Atlantic Coastal Plain region of southern Georgia (USA), cotton (Gossypium hirsutum L.) acreage increased threefold in the past decade. To more effectively protect water quality in the region, best management practices are needed that reduce pesticide runoff from fields in cotton production. This study compared runoff of two herbicides, fluometuron [N,N-dimethyl-N'-[3-(trifluoromethyl)-phenyl]-urea] and pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitro-benzenamine], from plots in strip-tillage (ST) and conventional-tillage (CT) management near Tifton, GA. Rainfall simulations were conducted one day after preemergence herbicide applications to 0.0006-ha plots and runoff from 0.15-ha plots due to natural rainfall following preemergence pendimethalin and fluometuron and postemergence fluometuron use was monitored. Pendimethalin runoff was greater under CT than ST due to strong pendimethalin soil sorption and higher erosion and runoff under CT. The highest losses, 1.3% of applied in CT and 0.22% of applied in ST, were observed during rainfall simulations conducted 1 DAT. Fluometuron runoff from natural rainfall was substantially lower from ST than from CT plots but the trend was reversed in rainfall simulations. In all studies, fluometuron runoff was also relatively low (<1% of applied), and on plots under natural rainfall, desmethylfluometuron (DMF) represented about 50% of total fluometuron runoff. Fluometuron's relatively low runoff rate appeared linked to its rapid leaching, and high DMF detection rates in runoff support DMF inclusion in fluometuron risk assessments. Results showed that ST has the potential to reduce runoff of both herbicides, but fluometuron leaching may be a ground water quality concern.

  9. Leaching Mechanisms Program. Annual report

    International Nuclear Information System (INIS)

    Dougherty, D.; Colombo, P.; Doty, R.; Fuhrmann, M.

    1984-09-01

    The primary goal of this work is to determine the leaching mechanisms of a variety of matrix materials either in use or being considered for the solidification of low-level radioactive wastes by defense and commercial waste generators. Since this program is new and did not formally begin until May of FY 84, the results reported here are few and preliminary. Efforts were concentrated in the following activities: (1) The literature search for leaching data and proposed leaching models and mechanisms for low-level waste. (2) Data base development for leaching data being compiled from the literature and from the leaching experiments in this program. (3) The selection of solidification agents for the experimental part of the program. (4) Fabrication of leach samples and initiation of leach testing. 28 references, 9 figures, 4 tables

  10. Leaching materials from cavities

    International Nuclear Information System (INIS)

    Hodgson, T.D.; Jordan, T.W.J.

    1980-01-01

    A material is leached from a cavity by contacting the material with a liquid and subjecting the liquid to a number of pressure cycles, each pressure cycle involving a decrease in pressure to cause boiling of the liquid, followed by a rise in pressure to inhibit the boiling. The method may include the step of heating the liquid to a temperature near to its boiling point. The material may be nuclear fuel pellets or calcium carbonate pellets. (author)

  11. Acid leaching of natural chrysotile asbestos to mesoporous silica fibers

    Science.gov (United States)

    Maletaškić, Jelena; Stanković, Nadežda; Daneu, Nina; Babić, Biljana; Stoiljković, Milovan; Yoshida, Katsumi; Matović, Branko

    2018-04-01

    Nanofibrous silica with a high surface area was produced from chrysotile by the acid-leaching method. Natural mineral chrysotile asbestos from Stragari, Korlace in Serbia was used as the starting material. The fibers were modified by chemical treatment with 1 M HCl and the mineral dissolution was monitored by transmission electron microscopy, X-ray powder diffraction, inductively coupled plasma spectrometry and low-temperature nitrogen adsorption techniques to highlight the effects of the leaching process. The results showed that the applied concentration of acid solution and processing time of 4 h were sufficient to effectively remove the magnesium hydroxide layer and transform the crystal structure of the hazardous starting chrysotile to porous SiO2 nanofibers. With prolonged acid leaching, the specific surface area, S BET, calculated by BET equation, was increased from 147 up to 435 m2 g- 1, with micropores representing a significant part of the specific surface.

  12. Sorption and leaching of benzalkonium chlorides in agricultural soils.

    Science.gov (United States)

    Khan, Adnan Hossain; Macfie, Sheila M; Ray, Madhumita B

    2017-07-01

    The adsorption and leaching characteristics of two commonly used benzalkonium chlorides (BACs), benzyl dimethyl dodecyl ammonium chloride (BDDA) and benzyl dimethyl tetradecyl ammonium chloride (BDTA) using three agricultural soils with varied proportions of silt, sand, clay, and organic matter were determined. BACs are cationic surfactants used in large quantities for sanitary and personal care products and are abundant in environmental samples. Adsorption isotherm data (aqueous concentration in the range of 25-150 mg L -1 ) fitted the Langmuir model better than the Freundlich model. BDTA with a longer alkyl chain adsorbed more to soil compared to BDDA, and the soil with the highest percentage of clay adsorbed the most. Column tests conducted using soils amended with lime stabilised biosolids and artificial rain water at a flow rate of 0.2 mL min -1 indicate very low leaching of BACs. Less than 1% of the available BDDA leached through sandy loam soil column with a depth of 9 cm. Therefore, the possibility of BACs to become bioavailable through leaching is very low at environmentally relevant concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Leaching mechanisms of constituents from fly ash under the influence of humic acid.

    Science.gov (United States)

    Zhao, Shengxin; Chen, Zhonglin; Shen, Jimin; Kang, Jing; Zhang, Jin; Shen, Yanqing

    2017-01-05

    As a low-cost material for adsorption, FA is one of the most efficient adsorbents of HA. However, the leaching of elements from FA is problematic during utilization in water treatment. In this investigation, the potential leaching behaviors of Calcium, Arsenic, Born, Chromium, and other elements from FA in HA solution were studied via batch test. The data show that HA had an effect on the leaching of each element of FA, depending on the pH, the initial concentration of HA and the addition of calcium oxide (CaO). The Langmuir isotherm could better fit the equilibrium data in different initial concentrations of HA from 10 to 100mg/L. Because of the interaction between HA and the FA leaching elements, multi-layer adsorption occurred when the initial concentration of HA was more than 100mg/L. The pH and free CaO content played major roles in HA adsorption and FA leaching. Using SEM and XRD to characterize the solid of FA being mixed with CaO treated in solution, the results demonstrated that the reaction between FA and CaO could generate crystal minerals, such as portlandite, gismondine, ettringite (AFt) and calcite, which effectively restrained the leaching of elements, reduced secondary pollution. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Dynamic simulation of the carbon-in-pulp and carbon-in-leach processes

    Directory of Open Access Journals (Sweden)

    L. R. P. de Andrade Lima

    2007-12-01

    Full Text Available Carbon-in-leach and carbon-in-pulp are continuous processes that use activated carbon in a cascade of large agitated tanks, which have been widely used to recover or concentrate precious metals in gold extraction plants. In the carbon-in-pulp process adsorption occurs after the leaching cascade section of the plant, and in the carbon-in-leach process leaching and adsorption occur simultaneously. In both processes the activated carbon is moved from one tank to another in countercurrent with the ore pulp until the recovery of the loaded carbon in the first tank. This paper presents a dynamic model that describes, with minor changes, the carbon-in-leach, the carbon-in-pulp, and the gold leaching processes. The model is numerically solved and calibrated with experimental data from a plant and used to perform a study of the effect of the activated carbon transfer strategy on the performance of the adsorption section of the plant. Based on the calculated values of the gold loss in the liquid and of the gold recovered in the loaded activated carbon that leaves the circuit, the results indicate that strategies in which a significant amount of activated carbon is held in the first tank and the contact time between the carbon and the pulp is longer are the best carbon transfer strategies for these processes.

  15. Leaching From Biomass Gasification Residues

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Boldrin, Alessio; Polletini, A.

    2011-01-01

    The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled with geoche......The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled...

  16. Leaching Test Relationships, Laboratory-to-Field Comparisons and Recommendations for Leaching Evaluation using the Leaching Environmental Assessment Framework (LEAF)

    Science.gov (United States)

    This report presents examples of the relationships between the results of laboratory leaching tests, as defined by the Leaching Environmental Assessment Framework (LEAF) or analogous international test methods, and leaching of constituents from a broad range of materials under di...

  17. Comparison between snowmelt-runoff and rainfall-runoff nonpoint source pollution in a typical urban catchment in Beijing, China.

    Science.gov (United States)

    Chen, Lei; Zhi, Xiaosha; Shen, Zhenyao; Dai, Ying; Aini, Guzhanuer

    2018-01-01

    As a climate-driven event, nonpoint source (NPS) pollution is caused by rainfall- or snowmelt-runoff processes; however, few studies have compared the characteristics and mechanisms of these two kinds of NPS processes. In this study, three factors relating to urban NPS, including surface dust, snowmelt, and rainfall-runoff processes, were analyzed comprehensively by both field sampling and laboratory experiments. The seasonal variation and leaching characteristics of pollutants in surface dust were explored, and the runoff quality of snowmelt NPS and rainfall NPS were compared. The results indicated that dusts are the main sources of urban NPS and more pollutants are deposited in dust samples during winter and spring. However, pollutants in surface dust showed a low leaching ratio, which indicated most NPS pollutants would be carried as particulate forms. Compared to surface layer, underlying snow contained higher chemical oxygen demand, total suspended solids (TSS), Cu, Fe, Mn, and Pb concentrations, while the event mean concentration of most pollutants in snowmelt tended to be higher in roads. Moreover, the TSS and heavy metal content of snowmelt NPS was always higher than those of rainfall NPS, which indicated the importance of controlling snowmelt pollution for effective water quality management.

  18. Transport of three veterinary antimicrobials from feedlot pens via simulated rainfall runoff.

    Science.gov (United States)

    Sura, Srinivas; Degenhardt, Dani; Cessna, Allan J; Larney, Francis J; Olson, Andrew F; McAllister, Tim A

    2015-07-15

    Veterinary antimicrobials are introduced to wider environments by manure application to agricultural fields or through leaching or runoff from manure storage areas (feedlots, stockpiles, windrows, lagoons). Detected in manure, manure-treated soils, and surface and ground water near intensive cattle feeding operations, there is a concern that environmental contamination by these chemicals may promote the development of antimicrobial resistance in bacteria. Surface runoff and leaching appear to be major transport pathways by which veterinary antimicrobials eventually contaminate surface and ground water, respectively. A study was conducted to investigate the transport of three veterinary antimicrobials (chlortetracycline, sulfamethazine, tylosin), commonly used in beef cattle production, in simulated rainfall runoff from feedlot pens. Mean concentrations of veterinary antimicrobials were 1.4 to 3.5 times higher in surface material from bedding vs. non-bedding pen areas. Runoff rates and volumetric runoff coefficients were similar across all treatments but both were significantly higher from non-bedding (0.53Lmin(-1); 0.27) than bedding areas (0.40Lmin(-1); 0.19). In keeping with concentrations in pen surface material, mean concentrations of veterinary antimicrobials were 1.4 to 2.5 times higher in runoff generated from bedding vs. non-bedding pen areas. Water solubility and sorption coefficient of antimicrobials played a role in their transport in runoff. Estimated amounts of chlortetracycline, sulfamethazine, and tylosin that could potentially be transported to the feedlot catch basin during a one in 100-year precipitation event were 1.3 to 3.6ghead(-1), 1.9ghead(-1), and 0.2ghead(-1), respectively. This study demonstrates the magnitude of veterinary antimicrobial transport in feedlot pen runoff and supports the necessity of catch basins for runoff containment within feedlots. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  19. Defining Effective Salt Leaching Regions Between Drains

    OpenAIRE

    ANAPALI, Ömer; ŞAHİN, Üstün; ÖZTAŞ, Taşkın; HANAY, Abdurrahman

    2014-01-01

    The application of sufficient amounts of leaching water by means of an effective method is very important in the management and reclamation of saline and sodic soils. Reclamation cannot be achieved with insufficient leaching water application, while excess water application may cause severe problems in soil. Knowledge of the leaching regions and intensities may help to control the amounts of leaching water through effective leaching methods in areas of limited leaching. This study was und...

  20. Decrease of non-point zinc runoff using porous concrete.

    Science.gov (United States)

    Harada, Shigeki; Komuro, Yoshinori

    2010-01-01

    The use of porous concrete columns to decrease the amount of zinc in stormwater runoff is examined. The concentration of zinc in a simulated stormwater fluid (zinc acetate solution), fed through concrete columns (slashed circle10x10cm) decreased by 50-81%, suggesting physical adsorption of zinc by the porous concrete. We propose the use of porous concrete columns (slashed circle50x10cm) as the base of sewage traps. Longer-term, high-zinc concentration monitoring revealed that porous concrete blocks adsorb 38.6mgcm(-3) of zinc. A period of no significant zinc runoff (with an acceptable concentration of zinc in runoff of 0.03mgL(-1), a zinc concentration equal to the Japanese Environmental Standard) is estimated for 41years using a 1-ha catchment area with 20 porous concrete sewage traps. Scanning electron microscopy of the porous concrete used in this study indicates that the needle-like particles formed by hydration action significantly increase zinc adsorption. Evidence suggests that the hydrant is ettringite and has an important role in zinc adsorption, the resulting immobilization of zinc and the subsequent effects on groundwater quality. Copyright 2009 Elsevier Ltd. All rights reserved.

  1. To accelerate technology of in situ leaching and heap leaching for mining mineral resources of China

    International Nuclear Information System (INIS)

    Luo Mei

    1999-01-01

    Recently, in situ leaching and heap leaching are the most advanced technology for mining low-grade mineral resources in the world. The author briefly expounds the basic concept and advantages of in situ leaching and heap leaching and deals with the main research content of the hydrometallurgical technology of in situ leaching and heap leaching, its development and present application at home and abroad. Having expounded the gap existing between China's technology of in situ leaching and heap leaching and the foreign technology, the author forecasts the prospects of accelerating the mining of China's mineral resources by using the technology of in situ leaching and heap leaching

  2. Adsorption, leaching and persistence of carbendazim in Brazilian soils

    International Nuclear Information System (INIS)

    Musumeci, M.R.; Lord, K.A.; Ruegg, E.F.

    1980-01-01

    Sorption, movement and degradation of carbendazin in gley humic, yellow red latosol and red latosol soils was studied in the laboratory using nuclear techniques. Soils rich in organic matter showed higher sorption and lower mobility. Carbendazin persisted in the three soils, higher degradation occuring in the humic gley soil, richest in organic matter. Recovery of carbendazin diminishes with time being lower in the soil richest in organic matter. After an incubation period of 150 days, 2-aminobenzimidazole a compound without fungitoxic activity was detected as the main degradation product of carbendazin. (Author) [pt

  3. Selective Adsorption of Uranium (VI) on NaHCO Leached ...

    African Journals Online (AJOL)

    NICO

    with a variety of organic and inorganic ligands to form complex species of different ... approach for the synthesis of magnetic particles for uranium .... equations (1) and (2), respectively. Extraction efficiency. (C. C ). C o e o. = −. × 100. (1).

  4. Phosphate Leaching from Green Roof Substrates—Can Green Roofs Pollute Urban Water Bodies?

    Directory of Open Access Journals (Sweden)

    Agnieszka Karczmarczyk

    2018-02-01

    Full Text Available Green roofs are an effective stormwater measure due to high water retention capacity and the ability of delaying stormwater runoff. However, low importance is still given to the pollutant leaching potential of substrates used in green roof construction. The aim of the study is to estimate the concentrations and loads of P-PO43− in runoff from extensive and intensive substrates. To achieve this goal, several commonly-used fresh substrates were analyzed for P-PO43− leaching potential in different scale experiments, from laboratory batch tests, leaching column experiments, and long-term monitoring of open air green roof containers. The results of the study confirmed that fresh green roof substrates contain phosphorus in significant amounts of 17–145 mg∙P-PO43−/kg and, thus, can contribute to eutrophication of freshwater ecosystems. High correlation between phosphate content estimated by HCl extraction and cumulative load in leachate tests suggests that the batch HCl extraction test can be recommended for the comparison and selection of substrates with low potential P leaching. Volume-weighted mean concentrations and UALs of P-PO43− leaching from fresh substrates were higher in cases of intensive substrates, but there was no clear relationship between substrate type and the observed P-PO43− concentration range. To avoid increasing eutrophication of urban receivers the implementation of P reduction measures is strongly recommended.

  5. Disposal of leached residual in heap leaching by neutralization

    International Nuclear Information System (INIS)

    Wang Jingmin

    1993-01-01

    The disposal results of leached residual with lime are described. Using the ratio of residual to lime being 100 : 1 the ideal disposal results were obtained with the effluent of the neutralized residual close to neutral

  6. Runoff of pesticides from rice fields in the Ile de Camargue (Rhone river delta, France): Field study and modeling

    International Nuclear Information System (INIS)

    Comoretto, Laetitia; Arfib, Bruno; Talva, Romain; Chauvelon, Philippe; Pichaud, Marc; Chiron, Serge; Hoehener, Patrick

    2008-01-01

    A field study on the runoff of pesticides was conducted during the cultivation period in 2004 on a hydraulically isolated rice farm of 120 ha surface with one central water outlet. Four pesticides were studied: Alphamethrin, MCPA, Oxadiazon, and Pretilachlor. Alphamethrin concentrations in runoff never exceeded 0.001 μg L -1 . The three other pesticides were found in concentrations between 5.2 and 28.2 μg L -1 in the runoff water shortly after the application and decreased thereafter. The data for MCPA compared reasonably well with predictions by an analytical runoff model, accounting for volatilization, degradation, leaching to groundwater, and sorption to soil. The runoff model estimated that runoff accounted for as much as 18-42% of mass loss for MCPA. Less runoff is observed and predicted for Oxadiazon and Pretilachlor. It was concluded that runoff from rice paddies carries important loads of dissolved pesticides to the wetlands in the Ile de Camargue, and that the model can be used to predict this runoff. - Runoff of dissolved pesticides was measured on a rice farm in the Camargue (France) and modeled with an analytical model

  7. Mechanism for elevated temperature leaching

    International Nuclear Information System (INIS)

    Kenna, B.T.; Murphy, K.D.

    1979-01-01

    Long-term, elevated temperature leaching and subsequent electron microprobe analysis of simulated waste glass and ceramic materials have been completed. A cyclic leaching pattern was found in all systems over a 20-month period. It appears that the leaching of mobile ions by simple diffusional processes is modified by more complex chemical interactions. The release of immobile ions is primarily a function of their chemical interactions in the matrix which suggests that these ions may be complex species when released into solution. A mechanism is proposed which incorporates these ideas and the cyclic phenomenon observed

  8. Leaching of concrete : the leaching process : extrapolation of deterioration : effect on the structural stability

    OpenAIRE

    Fagerlund, Göran

    2000-01-01

    The leaching process when water attacks concrete, and the effect of leaching on the strength and durability of a concrete structure, is analysed theoretically. Technique for prediction of the future leaching and structural stability is outlined. The analysis is to a certain extent supported by data from literature. The leaching process is divided in five different types: 1: Pure surface leaching 2: Surface leaching involving erosion 3: Homogeneous leaching over the entire structure 4...

  9. Characterizations of the first flush in storm water runoff from an urban roadway.

    Science.gov (United States)

    Lee, B C; Matsui, S; Shimizu, Y; Matsuda, T

    2005-07-01

    Storm water runoff from urban roadways contains anthropogenic pollutants, which are mainly generated from traffic-related activities. The purpose of this study was to evaluate the characteristics of pollutants from the roadway runoff as well as first flush effects. Storm water runoff was sampled during five storm events from the experimental site in Otsu, Shiga, Japan. From the hydrographs and pollutographs for the roadway runoff, the concentration of pollutants increased with increasing runoff flow in the low flow rate event, but did not significantly increase in the high flow rate event. Moreover, according to the analysis of cumulative pollutant mass versus runoff volume curves from five storm events, the first 50% of the runoff volume transported 62% of TOC and Mo, 60% of SS, 59% of Fe, Mn and Cu, 58% of Ni, 57% of Cd and Pb, 56% of Al, 55% of Zn, and 54% of Cr, as the mean values. The first 30% and 80% of the runoff volume also transported 34-43% mass of the pollutants and 82-88% mass of the pollutants, respectively. This study for storm water runoff may also provide useful information to correctly design treatment facilities, such as detention tanks and ponds, filtration and adsorption systems.

  10. Modelling and simulation of concrete leaching under outdoor exposure conditions

    International Nuclear Information System (INIS)

    Schiopu, Nicoleta; Tiruta-Barna, Ligia; Jayr, Emmanuel; Mehu, Jacques; Moszkowicz, Pierre

    2009-01-01

    Recently, a demand regarding the assessment of release of dangerous substances from construction products was raised by European Commission which has issued the Mandate M/366 addressed to CEN. This action is in relation with the Essential Requirement No. 3 'Hygiene, Health and Environment' of the Construction Products Directive (89/106/EC). The potential hazard for environment and health may arise in different life cycle stages of a construction product. During the service life stage, the release of substances due to contact with the rain water is the main potential hazard source, as a consequence of the leaching phenomenon. The objective of this paper is to present the development of a coupled chemical-transport model for the case of a concrete based construction product, i.e. concrete paving slabs, exposed to rain water under outdoor exposure conditions. The development of the model is based on an iterative process of comparing the experimental results with the simulated results up to an acceptable fit. The experiments were conducted at laboratory scale (equilibrium and dynamic leaching tests) and field scale. The product was exposed for one year in two types of leaching scenarios under outdoor conditions, 'runoff' and 'stagnation', and the element release was monitored. The model was calibrated using the experimental data obtained at laboratory scale and validated against measured field data, by taking into account the specific rain water balance and the atmospheric CO 2 uptake as input parameters. The numerical tool used in order to model and simulate the leaching behaviour was PHREEQC, coupled with the Lawrence Livermore National Laboratory (LLNL) thermodynamic data base. The simulation results are satisfying and the paper demonstrates the feasibility of the modelling approach for the leaching behaviour assessment of concrete type construction materials

  11. Comparison of leaching tests and study of leaching mechanisms

    International Nuclear Information System (INIS)

    Amarantos, S.G.; Papadokostaki, K.G.; Petropoulos, J.H.

    1985-10-01

    The present work is concerned first with the study of certain aspects of the leaching kinetics of Cs + and Sr ++ embedded in cement, as Cs 2 SO 4 and SrSO 4 , and in particular: (a) the comparative evaluation of leaching in (i) stagnant, (ii) stirred and (iii) continuously flowing (modified Soxhlet) water, (b) the effect of atmospheric CO 2 on elution, (c) the effect of temperature changes during leaching. Secondly, model kinetic studies were carried out using cellulose acetate incorporating SrSO 4 , CaSO 4 or NaCl. The main results obtained were: (1) Cs leaching rates were not significantly affected by the leaching method or by the presence of atmospheric CO 2 . The embedded Cs exists in relatively easily leachable and less rapidly leachable (most probably located within the gel regions) forms. (2) Elution of Sr is retarded by stagnant and infrequently renewed leachant (method (i)) and by the presence of atmospheric CO 2 ; leaching method (iii), which tends to minimize both of these effects, gave the highest elution rates. (3) The observed elution kinetics in the case of cellulose acetate-CaSO 4 or SrSO 4 conform to the Higuchi model, but a more elaborate theory is needed for the cellulose acetate-NaCl system. (author)

  12. LEACH-A: An Adaptive Method for Improving LEACH Protocol

    Directory of Open Access Journals (Sweden)

    Jianli ZHAO

    2014-01-01

    Full Text Available Energy has become one of the most important constraints on wireless sensor networks. Hence, many researchers in this field focus on how to design a routing protocol to prolong the lifetime of the network. The classical hierarchical protocols such as LEACH and LEACH-C have better performance in saving the energy consumption. However, the choosing strategy only based on the largest residue energy or shortest distance will still consume more energy. In this paper an adaptive routing protocol named “LEACH-A” which has an energy threshold E0 is proposed. If there are cluster nodes whose residual energy are greater than E0, the node of largest residual energy is selected to communicated with the base station; When all the cluster nodes energy are less than E0, the node nearest to the base station is select to communication with the base station. Simulations show that our improved protocol LEACH-A performs better than the LEACH and the LEACH-C.

  13. Phosphorus leaching from soil cores from a twenty-year study evaluating alum treatment of poultry litter

    Science.gov (United States)

    Adding alum (aluminum sulfate) to poultry litter is a best management practice (BMP) used to stabilize phosphorus (P) in less soluble forms, reducing non-point source P runoff. However, little research has been conducted on the effects of alum-treated poultry litter on P leaching. The objective of...

  14. A glacier runoff extension to the Precipitation Runoff Modeling System

    Science.gov (United States)

    A. E. Van Beusekom; R. J. Viger

    2016-01-01

    A module to simulate glacier runoff, PRMSglacier, was added to PRMS (Precipitation Runoff Modeling System), a distributed-parameter, physical-process hydrological simulation code. The extension does not require extensive on-glacier measurements or computational expense but still relies on physical principles over empirical relations as much as is feasible while...

  15. Next Generation of Leaching Tests

    Science.gov (United States)

    A corresponding abstract has been cleared for this presentation. The four methods comprising the Leaching Environmental Assessment Framework are described along with the tools to support implementation of the more rigorous and accurate source terms that are developed using LEAF ...

  16. Pressure leaching of chalcopyrite concentrate

    Science.gov (United States)

    Aleksei, Kritskii; Kirill, Karimov; Stanislav, Naboichenko

    2018-05-01

    The results of chalcopyrite concentrate processing using low-temperature and high-temperature sulfuric acid pressure leaching are presented. A material of the following composition was used, 21.5 Cu, 0.1 Zn, 0.05 Pb, 0.04 Ni, 26.59 S, 24.52 Fe, 16.28 SiO2 (in wt.%). The influence of technological parameters on the degree of copper and iron extraction into the leach solution was studied in the wide range of values. The following conditions were suggested as the optimal for the high-temperature pressure leaching: t = 190 °C, PO2 = 0.5 MPa, CH2SO4 = 15 g/L, L:S = 6:1. At the mentioned parameters, it is possible to extract at least 98% Cu from concentrate into the leaching solution during 100 minutes. The following conditions were suggested as optimal for the low-temperature pressure leaching: t = 105 °C, PO2 = 1.3-1.5 MPa, CH2SO4 = 90 g/L, L:S = 10:1. At the mentioned parameters, it is possible to extract up to 83% Cu from the concentrate into the leach solution during 300-360 minutes.

  17. Leaching tendencies of uranium and regulated trace metals from the Hanford Site 300 Area North Process Pond sediments

    International Nuclear Information System (INIS)

    Serne, R.J.; LeGore, V.L.; Mattigod, S.V.

    1994-09-01

    Data are presented that address the leaching tendencies and the total chemical composition of metals in feed materials and soil-washed fines generated by Alternative Remediation Technology, Inc. during a pilot-scale soil physical separation test performed at the 300 Area North Process Pond (Facility 316-2) on the Hanford Site in the spring of 1994. Four 300 Area North Process Pond sediments and one sediment from outside the pond's fenced area were leach-tested using the Toxicity Characteristic Leach Procedure (TCLP) and other modified US Environmental Protection Agency and American Society for Testing and Materials protocols. Finally, leachate from the most contaminated sediment was used to load the Hanford sediment obtained outside the facility to evaluate the potential for contaminant adsorption onto natural sediments. The sediment characterization, leach, and adsorption results will be used in the evaluation of remedial alternatives in the 300-FF-1 Operable Unit Remedial Investigation/Feasibility Study

  18. Ultrasound-assisted leaching of rare earths from the weathered crust elution-deposited ore using magnesium sulfate without ammonia-nitrogen pollution.

    Science.gov (United States)

    Yin, Shaohua; Pei, Jiannan; Jiang, Feng; Li, Shiwei; Peng, Jinhui; Zhang, Libo; Ju, Shaohua; Srinivasakannan, Chandrasekar

    2018-03-01

    The in situ leaching process of China's unique ion-adsorption rare earth ores has caused severe environmental damages due to the use of (NH 4 ) 2 SO 4 solution. This study reports that magnesium sulfate (MgSO 4 ) as a leaching agent would replace (NH 4 ) 2 SO 4 by ultrasonically assisted leaching to deal with the ammonia-nitrogen pollution problem and enhance leaching process. At leaching conditions of 3wt% MgSO 4 concentration, 3:1L/S ratio and 30min, the total rare earth leaching efficiency reaches 75.5%. Ultrasound-assisted leaching experiments show that the leaching efficiency of rare earths is substantially increased by introducing ultrasound, and nearly completely leached out after two stage leaching process. Thus, ultrasonic-assisted leaching process with MgSO 4 is not only effective but also environmentally friendly, and beneficial to leach rare earths at laboratory scale. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Characteristics of PAHs in farmland soil and rainfall runoff in Tianjin, China.

    Science.gov (United States)

    Shi, Rongguang; Xu, Mengmeng; Liu, Aifeng; Tian, Yong; Zhao, Zongshan

    2017-10-14

    Rainfall runoff can remove certain amounts of pollutants from contaminated farmland soil and result in a decline in water quality. However, the leaching behaviors of polycyclic aromatic hydrocarbons (PAHs) with rainfall have been rarely reported due to wide variations in the soil compositions, rainfall conditions, and sources of soil PAHs in complex farmland ecosystems. In this paper, the levels, spatial distributions, and composition profiles of PAHs in 30 farmland soil samples and 49 rainfall-runoff samples from the Tianjin region in 2012 were studied to investigate their leaching behaviors caused by rainfall runoff. The contents of the Σ 16 PAHs ranged from 58.53 to 3137.90 μg/kg in the soil and 146.58 to 3636.59 μg/L in the runoff. In total, most of the soil sampling sites (23 of 30) were contaminated, and biomass and petroleum combustion were proposed as the main sources of the soil PAHs. Both the spatial distributions of the soil and the runoff PAHs show a decreasing trend moving away from the downtown, which suggested that the leaching behaviors of PAHs in a larger region during rainfall may be mainly affected by the compounds themselves. In addition, 4- and 5-ring PAHs are the dominant components in farmland soil and 3- and 4-ring PAHs dominate the runoff. Comparisons of the PAH pairs and enrichment ratios showed that acenaphthylene, acenaphthene, benzo[a]anthracene, chrysene, and fluoranthene were more easily transferred into water systems from soil than benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, and indeno[123-cd]pyrene, which indicated that PAHs with low molecular weight are preferentially dissolved due to their higher solubility compared to those with high molecular weight.

  20. Nitrate Leaching from Winter Cereal Cover Crops Using Undisturbed Soil-Column Lysimeters.

    Science.gov (United States)

    Meisinger, John J; Ricigliano, Kristin A

    2017-05-01

    Cover crops are important management practices for reducing nitrogen (N) leaching, especially in the Chesapeake Bay watershed, which is under total maximum daily load (TMDL) restraints. Winter cereals are common cool-season crops in the Bay watershed, but studies have not directly compared nitrate-N (NO-N) leaching losses from these species. A 3-yr cover crop lysimeter study was conducted in Beltsville, MD, to directly compare NO-N leaching from a commonly grown cultivar of barley ( L.), rye ( L.), and wheat ( L.), along with a no-cover control, using eight tension-drained undisturbed soil column lysimeters in a completely randomized design with two replicates. The lysimeters were configured to exclude runoff and to estimate NO-N leaching and flow-weighted NO-N concentration (FWNC). The temporal pattern of NO-N leaching showed a consistent highly significant ( leaching with cover crops compared with no cover but showed only small and periodically significant ( leaching was more affected by the quantity of establishment-season (mid-October to mid-December) precipitation than by cover crop species. For example, compared with no cover, winter cereal covers reduced NO-N leaching 95% in a dry year and 50% in wet years, with corresponding reductions in FWNC of 92 and 43%, respectively. These results are important for scientists, nutrient managers, and policymakers because they directly compare NO-N leaching from winter cereal covers and expand knowledge for developing management practices for winter cereals that can improve water quality and increase N efficiency in cropping systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  1. Runoff inundation hazard cartography

    Science.gov (United States)

    Pineux, N.; Degré, A.

    2012-04-01

    Between 1998 and 2004, Europe suffered from more than hundred major inundations, responsible for some 700 deaths, for the moving of about half a million of people and the economic losses of at least 25 billions Euros covered by the insurance policies. Within this context, EU launched the 2007/60/CE directive. The inundations are natural phenomenon. They cannot be avoided. Nevertheless this directive permits to better evaluate the risks and to coordinate the management measures taken at member states level. In most countries, inundation maps only include rivers' overflowing. In Wallonia, overland flows and mudflows also cause huge damages, and must be included in the flood hazard map. Indeed, the cleaning operations for a village can lead to an estimated cost of 11 000 €. Average construction cost of retention dams to control off-site damage caused by floods and muddy flows was valued at 380 000€, and yearly dredging costs associated with these retention ponds at 15 000€. For a small city for which a study was done in a more specific way (Gembloux), the mean annual cost for the damages that can generate the runoff is about 20 000€. This cost consists of the physical damages caused to the real estate and movable properties of the residents as well as the emergency operations of the firemen and the city. On top of damages to public infrastructure (clogging of trenches, silting up of retention ponds) and to private property by muddy flows, runoff generates a significant loss of arable land. Yet, the soil resource is not an unlimited commodity. Moreover, sediments' transfer to watercourses alters their physical and chemical quality. And that is not to mention the increased psychological stress for people. But to map overland flood and mud flow hazard is a real challenge. This poster will present the methodology used to in Wallonia. The methodology is based on 3 project rainfalls: 25, 50 and 100 years return period (consistency with the cartography of the

  2. Evaluation of six pesticides leaching indexes using field data of herbicide application in Casablanca Valley, Chile.

    Science.gov (United States)

    Kogan, M; Rojas, S; Gómez, P; Suárez, F; Muñoz, J F; Alister, C

    2007-01-01

    A field study was performed to evaluate the accuracy of six pesticide screening leaching indexes for herbicide movement. Adsorption, dissipation and soil movement were studied in a vineyard in a sandy loam soil during 2005 season. Simazine, diuron, pendimethalin, oxyfluorfen and flumioxazin were applied to bare soil at rates commonly used, and their soil concentrations throughout soil profile were determined at 0, 10, 20, 40 and 90 days after application (DAA). Herbicides were subjected to two pluviometric regimens, natural field condition and modified conditions (plus natural rainfall 180 mm). Leaching indexes utilized were: Briggs's Rf, Hamaker's Rf, LEACH, LPI, GUS and LIX. Simazine reached 120 cm, diuron 90 cm, flumioxazin 30 cm soil depth respectively. Pendimethalin and oxyfluorfen were retained up to 5 cm. None of the herbicides leaching was affected by rainfall regimen. Only flumioxazin field dissipation was clearly affected by pluviometric condition. The best representation of the herbicide soil depth movement and leaching below 15 cm soil depth were: Hamaker's Rf < Briggs's Rf < GUS < LPI, < LEACH < LIX. Field results showed a good correlation between herbicides K(d) and their soil depth movement and mass leached below 15 cm soil depth.

  3. Uranium nanoparticle synthesis from leaching solution

    International Nuclear Information System (INIS)

    Sadowski, Z.; Sklodowska, A.

    2014-01-01

    The removal of uranium from leaching and bioleaching solutions is of great significance for an environment protection. In comparison with conventional separation techniques, synthesis of uranium nanoparticles has a number of benefits. It has been demonstrated that the uranium nanoparticles show high catalytic activity. In the present studies a variety of synthesis systems have been used for reduction of uranium from bioleaching solution. Among various catalytical templates the hematite Fe_2O_3 nanoparticles are most interest It was presented the report on development of synthesis method to produce nano structured Fe_2O_3 particles. The efficiency of hematite nanoparticles for adsorption of uranium ions from bioleaching solutions was investigated. Bacterial leaching is alternate technique used to extract uranium from mining wastes. The bioleaching process is environment friendly and gives the extraction yield of over 90%. The bioleaching solutions were obtained from bioleaching experiments using waste materials from different places at Lower Silesia (Kowary, Grzmiaca, Kopaniec, Radoniow). Chemoautotrophic bacteria were used for bioleaching tests. The significant adsorption capacity of U(VI) onto iron oxide and hydroxides (goethite, hematite, and magnetite) was observed. The sorption of U(VI) onto the hematite surface was connected with the chemical reduction of U(VI) to U(IV) by Fe"2"+ ions. The initial reaction system contained excess of Fe"2"+ ions which were used to reduce of U(VI). The reduction of U(VI) occurred at pH at the vicinity of pH=2.4. The colloid particles of hematite with UO_2 nanoparticles were obtained. The results of zeta potential measurements of hematite nanoparticles showed that at the ionic strength equals 10"-"3M NaCl, the average zeta potential was +32.4±3.5 mV at pH = 2.6. The interaction of hematite nanoparticles with the bioleaching solutions led to decrease of positive zeta potential to the value of 6.4± 2.7 mV. (author)

  4. Leaching risk of N-nitrosodimethylamine (NDMA) in soil receiving reclaimed wastewater.

    Science.gov (United States)

    Haruta, Shinsuke; Chen, Weiping; Gan, Jay; Simůnek, Jirka; Chang, Andrew C; Wu, Laosheng

    2008-03-01

    N-nitrosodimethylamine (NDMA) is a potential carcinogen frequently found in treated wastewater as a byproduct of chlorination. The potential for NDMA to contaminate the groundwater is a significant concern. A solute fate and transport model, Hydrus-1D, was used to evaluate the leaching potential of NDMA under different irrigation practices and soil properties. The results indicate that the risk of NDMA to reach the ground water is slim, when the reclaimed wastewater is applied under the customary conditions for landscape irrigation. The NDMA disappears in the reclaimed wastewater receiving soils rapidly through the microbial degradation and the volatilization processes. The factors that enhance the leaching risk are the soil hydraulic conductivity, the NDMA adsorption constants, and the irrigation intensity. When the hydraulic conductivity of soil is high, the NDMA adsorption constant of soil is low and/or the irrigation intensity is high, the NDMA leaching risk may dramatically increase. To reduce the NDMA leaching risk, it is imperative that the fields be irrigated at the proper volume and frequency and attention be paid to fields with soils having high-hydraulic conductivities and/or low-NDMA adsorption constants.

  5. Depuration of highway runoff water into grass-covered embankments.

    Science.gov (United States)

    Boivin, P; Saadé, M; Pfeiffer, H R; Hammecker, C; Degoumois, Y

    2008-06-01

    The management of polluted road runoff water is an important issue in environmental protection. A strategy could be to perform local depuration by infiltration into the soils of the embankment, but knowledge for designing such systems is lacking. This study aims at discussing the relevant soil properties, by estimating the long-term depuration of road runoff water infiltrating into the sandy soil embankment of the A9 highway in Wallis, Switzerland. This was done by estimating the heavy metals (HM) mass balance of two sites 23 and 12 years old, respectively. The accumulated HM were estimated by soil and GB analyses. The HM input was estimated by average water quality and traffic. The results were discussed using two-dimensional simulation of infiltration and a 14 months in situ monitoring of the runoff from the pavement to the embankment and at the bottom of the embankment. The soil properties were appropriate for both small particle adsorption and filtration. A good match between input and stored pollutant charges was found, and the HM profiles accorded well with infiltration simulation and monitoring results, which showed that 80-100% of the runoff water infiltrated into the embankment. Replacement of the cracked concrete gutters by an infiltration channel made of similar soil is recommended. These results oppose the Swiss guidelines for road-polluted water infiltration, as much more clayey soils are recommended. These later soils are difficult to find in Switzerland, and may allow for preferential flow through macro pores, in contrast to the studied site.

  6. A pilot study to evaluate runoff quantity from green roofs.

    Science.gov (United States)

    Lee, Ju Young; Lee, Min Jung; Han, Mooyoung

    2015-04-01

    The use of green roofs is gaining increased recognition in many countries as a solution that can be used to improve environmental quality and reduce runoff quantity. To achieve these goals, pilot-scale green roof assemblies have been constructed and operated in an urban setting. From a stormwater management perspective, green roofs are 42.8-60.8% effective in reducing runoff for 200 mm soil depth and 13.8-34.4% effective in reducing runoff for 150 mm soil depth. By using Spearman rank correlation analysis, high rainfall intensity was shown to have a negative relationship with delayed occurrence time, demonstrating that the soil media in green roofs do not efficiently retain rainwater. Increasing the number of antecedent dry days can help to improve water retention capacity and delay occurrence time. From the viewpoint of runoff water quality, green roofs are regarded as the best management practice by filtration and adsorption through growth media (soil). Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. NEXT GENERATION LEACHING TESTS FOR EVALUATING LEACHING OF INORGANIC CONSTITUENTS

    Science.gov (United States)

    In the U.S. as in other countries, there is increased interest in using industrial by-products as alternative or secondary materials, helping to conserve virgin or raw materials. The LEAF and associated test methods are being used to develop the source term for leaching or any i...

  8. Urban Runoff: National Management Measures

    Science.gov (United States)

    This helps citizens and municipalities in urban areas protect bodies of water from polluted runoff . These scientifically sound techniques are the best practices known today. The guidance helps states to implement their nonpoint source control program.

  9. 29 CFR 102.70 - Runoff election.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 2 2010-07-01 2010-07-01 false Runoff election. 102.70 Section 102.70 Labor Regulations... Runoff election. (a) The regional director shall conduct a runoff election, without further order of the... objections are filed as provided in § 102.69. Only one runoff shall be held pursuant to this section. (b...

  10. 5 CFR 2422.28 - Runoff elections.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Runoff elections. 2422.28 Section 2422.28... FEDERAL LABOR RELATIONS AUTHORITY REPRESENTATION PROCEEDINGS § 2422.28 Runoff elections. (a) When a runoff may be held. A runoff election is required in an election involving at least three (3) choices, one of...

  11. Selective leaching studies of deep-sea sediments loaded with americium, neptunium and plutonium

    International Nuclear Information System (INIS)

    Cole, T.G.; Higgo, J.J.W.; Cronan, D.S.; Rees, L.V.C.

    1984-07-01

    A series of selective leaching experiments were undertaken to investigate the solid phase speciation and distribution of americium, neptunium and plutonium which had been experimentally loaded onto different marine sediment types. The chemical leaches employed showed rather poor selectivity but certain trends were evident. Adsorption was not by ion exchange. Americium showed a preferential affinity for carbonate and plutonium for organic matter. Neptunium appeared to have no preferential affinities. Americium was sorbed by acetic acid residues (CaCO 3 removed) and by unleached carbonate-rich sediments with equal efficiency. This indicates that it is able to diversify its solid phase affinity/distribution depending upon which solid phases are available. (author)

  12. Mineral Adsorbents for Removal of Metals in Urban Runoff

    Science.gov (United States)

    Bjorklund, Karin; Li, Loretta

    2014-05-01

    The aim of this research was to determine the capacity of four different soil minerals to adsorb metals frequently detected in urban runoff. These are low-cost, natural and commercially available soil minerals. Contaminated surface runoff from urban areas is a major cause of concern for water quality and aquatic ecosystems worldwide. Pollution in urban areas is generated by a wide array of non-point sources, including vehicular transportation and building materials. Some of the most frequently detected pollutants in urban runoff are metals. Exhaust gases, tire wear and brake linings are major sources of such metals as Pb, Zn and Cu, while impregnated wood, plastics and galvanized surfaces may release As, Cd, Cr and Zn. Many metals have toxic effects on aquatic plants and animals, depending on metal speciation and bioavailability. The removal efficiency of pollutants in stormwater depends on treatment practices and on the properties the pollutant. The distribution of metals in urban runoff has shown, for example, that Pb is predominantly particle-associated, whereas Zn and Cd are present mainly in dissolved form. Many metals are also attached to colloids, which may act as carriers for contaminants, thereby facilitating their transport through conventional water treatment processes. Filtration of stormwater is one of the most promising techniques for removal of particulates, colloidal and truly dissolved pollutants, provided that effective filtration and adsorption media are used. Filtration and infiltration are used in a wide array of stormwater treatment methods e.g. porous paving, infiltration drains and rain gardens. Several soil minerals were investigated for their potential as stormwater filter materials. Laboratory batch tests were conducted to determine the adsorption capacity of these minerals. A synthetic stormwater was tested, with spiked concentrations corresponding to levels reported in urban runoff, ranging from 50-1,500 µg/L for Zn; 5-250 µg/L for Cu

  13. Implementation of the Leaching Environmental Assessment Framework

    Science.gov (United States)

    New leaching tests are available in the U.S. for developing more accurate source terms for use in fate and transport models. For beneficial use or disposal, the use of the leaching environmental assessment framework (LEAF) will provide leaching results that reflect field condit...

  14. Standard leach tests for nuclear waste materials

    International Nuclear Information System (INIS)

    Strachan, D.M.; Barnes, B.O.; Turcotte, R.P.

    1980-01-01

    Five leach tests were conducted to study time-dependent leaching of waste forms (glass). The first four tests include temperature as a variable and the use of three standard leachants. Three of the tests are static and two are dynamic (flow). This paper discusses the waste-form leach tests and presents some representative data. 4 figures

  15. Benzalkonium runoff from roofs treated with biocide products - In situ pilot-scale study.

    Science.gov (United States)

    Gromaire, M C; Van de Voorde, A; Lorgeoux, C; Chebbo, G

    2015-09-15

    Roof maintenance practices often involve the application of biocide products to fight against moss, lichens and algae. The main component of these products is benzalkonium chloride, a mixture of alkyl benzyl dimethyl ammonium chlorides with mainly C12 and C14 alkyl chain lengths, which is toxic for the aquatic environment. This paper describes, on the basis of an in-situ pilot scale study, the evolution of roof runoff contamination over a one year period following the biocide treatment of roof frames. Results show a major contamination of roof runoff immediately after treatment (from 5 to 30 mg/L), followed by an exponential decrease. 175-375 mm of cumulated rainfall is needed before the runoff concentrations become less than EC50 values for fish (280 μg/l). The residual concentration in the runoff water remains above 4 μg/L even after 640 mm of rainfall. The level of benzalkonium ions leaching depends on the roofing material, with lower concentrations and total mass leached from ceramic tiles than from concrete tiles, and on the state of the tile (new or worn out). Mass balance calculations indicate that a large part of the mass of benzalkonium compounds applied to the tiles is lost, probably due to biodegradation processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Copper leaching of MSWI bottom ash co-disposed with refuse: effect of short-term accelerated weathering.

    Science.gov (United States)

    Su, Lianghu; Guo, Guangzhai; Shi, Xinlong; Zuo, Minyu; Niu, Dongjie; Zhao, Aihua; Zhao, Youcai

    2013-06-01

    Co-disposal of refuse with municipal solid waste incinerator (MSWI) bottom ash (IBA) either multi-layered as landfill cover or mixed with refuse could pose additional risk to the environment because of enhanced leaching of heavy metals, especially Cu. This study applied short-term accelerated weathering to IBA, and monitored the mineralogical and chemical properties of IBA during the weathering process. Cu extractability of the weathered IBA was then evaluated using standard leaching protocols (i.e. SPLP and TCLP) and co-disposal leaching procedure. The results showed that weathering had little or no beneficial effect on Cu leaching in SPLP and TCLP, which can be explained by the adsorption and complexation of Cu with DOM. However, the Cu leaching of weathered IBA was reduced significantly when situated in fresh simulated landfill leachate. This was attributed to weakening Cu complexation with fulvic acid or hydrophilic fractions and/or intensifying Cu absorption to neoformed hydr(oxide) minerals in weathered IBA. The amount of total leaching Cu and Cu in free or labile complex fraction (the fraction with the highest mobility and bio-toxicity) of the 408-h weathered IBA were remarkably decreased by 86.3% and 97.6% in the 15-day co-disposal leaching test. Accelerated weathering of IBA may be an effective pretreatment method to decrease Cu leaching prior to its co-disposal with refuse. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Estimating subsoil resistance to nitrate leaching from easily measurable pedological properties

    Directory of Open Access Journals (Sweden)

    Fábio Keiti Nakagawa

    2012-11-01

    Full Text Available Leaching of nitrate (NO3- can increase the groundwater concentration of this anion and reduce the agronomical effectiveness of nitrogen fertilizers. The main soil property inversely related to NO3- leaching is the anion exchange capacity (AEC, whose determination is however too time-consuming for being carried out in soil testing laboratories. For this reason, this study evaluated if more easily measurable soil properties could be used to estimate the resistance of subsoils to NO3- leaching. Samples from the subsurface layer (20-40 cm of 24 representative soils of São Paulo State were characterized for particle-size distribution and for chemical and electrochemical properties. The subsoil content of adsorbed NO3- was calculated from the difference between the NO3- contents extracted with 1 mol L-1 KCl and with water; furthermore, NO3- leaching was studied in miscible displacement experiments. The results of both adsorption and leaching experiments were consistent with the well-known role exerted by AEC on the nitrate behavior in weathered soils. Multiple regression analysis indicated that in subsoils with (i low values of remaining phosphorus (Prem, (ii low soil pH values measured in water (pH H2O, and (iii high pH values measured in 1 moL L-1 KCl (pH KCl, the amounts of surface positive charges tend to be greater. For this reason, NO3- leaching tends to be slower in these subsoils, even under saturated flow condition.

  18. Assessment of runoff contributing catchment areas in rainfall runoff modelling

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Johansen, C.; Schaarup-Jensen, Kjeld

    2006-01-01

    In numerical modelling of rainfall caused runoff in urban sewer systems an essential parameter is the hydrological reduction factor which defines the percentage of the impervious area contributing to the surface flow towards the sewer. As the hydrological processes during a rainfall are difficult...... to determine with significant precision the hydrological reduction factor is implemented to account all hydrological losses except the initial loss. This paper presents an inconsistency between calculations of the hydrological reduction factor, based on measurements of rainfall and runoff, and till now...... recommended literature values for residential areas. It is proven by comparing rainfall-runoff measurements from four different residential catchments that the literature values of the hydrological reduction factor are over-estimated for this type of catchment. In addition, different catchment descriptions...

  19. Assessment of Runoff Contributing Catchment Areas in Rainfall Runoff Modelling

    DEFF Research Database (Denmark)

    Thorndahl, Søren Liedtke; Johansen, C.; Schaarup-Jensen, Kjeld

    2005-01-01

    to determine with significant precision the hydrological reduction factor is implemented to account all hydrological losses except the initial loss. This paper presents an inconsistency between calculations of the hydrological reduction factor, based on measurements of rainfall and runoff, and till now...... recommended literary values for residential areas. It is proven by comparing rainfall-runoff measurements from four different residential catchments that the literary values of the hydrological reduction factor are over-estimated for this type of catchments. In addition, different catchment descriptions...

  20. Measurement of leach rates: a review

    International Nuclear Information System (INIS)

    Mendel, J.E.

    1982-01-01

    A historical perspective of the techniques that can be used to measure the leach rate of radioactive waste forms is presented. The achievement of leach rates that are as low as possible has been an important goal ever since the development of solidification processes for liquid radioactive wastes began in the 1950's. Leach tests can be divided into two major categories, dynamic and static, based on whether or not the leachant in contact with the test specimen is changed during the course of the test. Both types of tests have been used extensively. The results of leach tests can be used to compare waste forms, and that has been a major purpose of leach data heretofore; increasingly, however, the data now are needed for predicting long-term leaching behavior during geologic disposal. This requirement is introducing new complexities into leach testing methodology. 3 figures, 2 tables

  1. Surface Runoff of Pesticides from a Clay Loam Field in Sweden.

    Science.gov (United States)

    Larsbo, Mats; Sandin, Maria; Jarvis, Nick; Etana, Ararso; Kreuger, Jenny

    2016-07-01

    Pesticides stored at or close to the soil surface after field application can be mobilized and transported off the field when surface runoff occurs. The objective of our study was to quantify the potential pesticide losses in surface runoff from a conventionally managed agricultural field in a Swedish climate. This was achieved by measuring surface runoff volumes and concentrations in runoff of six spring-applied pesticides and autumn-applied glyphosate and its metabolite aminomethylphosphonic acid (AMPA). Measurements were performed for 3 yr both during the growing seasons and during intervening winter snowmelt periods on a clay loam field close to Uppsala. During growing seasons, surface runoff was generated on only five occasions during one 25-d period in 2012 when the infiltration capacity of the soil may have been reduced by structural degradation due to large cumulative rainfall amounts after harrowing. Concentrations in surface runoff exceeded Swedish water quality standards in all samples during this growing season for diflufenican and pirimicarb. Surface runoff was generated during three snowmelt periods during the winter of 2012-2013. All of the applied pesticides were found in snowmelt samples despite incorporation of residues by autumn plowing, degradation, and leaching into the soil profile during the period between spraying and sampling. Concentrations of glyphosate ranged from 0.12 to 7.4 μg L, and concentrations of AMPA ranged from 0 to 2.7 μg L. Our results indicate that temporal changes in hydraulic properties during the growing season and when the soil freezes during winter affect pesticide losses through surface runoff. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  2. Sensitivity of point scale surface runoff predictions to rainfall resolution

    Directory of Open Access Journals (Sweden)

    A. J. Hearman

    2007-01-01

    averaged rainfall under these soil and rainfall conditions and predictions of larger scale phenomena such as hillslope runoff and runon. It offers insight into how rainfall resolution can affect predicted amounts of water entering the soil and thus soil water storage and drainage, possibly changing our understanding of the ecological functioning of the system or predictions of agri-chemical leaching. The application of this sensitivity analysis to different rainfall regions in Western Australia showed that locations in the tropics with higher intensity rainfalls are more likely to have differences in infiltration excess predictions with different rainfall resolutions and that a general understanding of the prevailing rainfall conditions and the soil's infiltration capacity can help in deciding whether high rainfall resolutions (below 1 h are required for accurate surface runoff predictions.

  3. Trend towards reverse leach process

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    The South African gold mining industry is making notable strides in improving recovery methods for both gold and uranium with significant additions to profits because of higher efficiencies and reductions in costs in the recovery processes. The most notable step on the gold side recently is the adoption of the reverse leach process at Buffelsfontein and Western Deep Levels. This process was pioneered at Hartebeesfontein as far back as 1975 and when introduced there resulted in a two and a half per cent improvement in recovery efficiencies. The essence of reverse leaching under which the uranium is recovered before the gold is the fact that the gold partly coated with iron oxide or locked in uranite, is exposed to be recovered later by cyanidation

  4. Effect of Medicinal Plants Cultivation on the Physicochemical Properties of Leached Chernozem

    Science.gov (United States)

    Svistova, I. D.; Stekol'nikov, K. E.; Paramonov, A. Yu.; Kuvshinova, N. M.

    2016-02-01

    For the first time, a nonspecific neutralizing effect of rhizodeposits of medicinal plants has been found in a leached chernozem. The neutralization of actual, exchangeable, and total acidity of the soil takes place against the background of a decrease in the activity of calcium ions in the soil solution. It can be supposed that this effect is due to the release of secondary metabolites of phenol nature in the rhizodeposits. These substances can change the anionic composition of the soil adsorption complex. Plant species with the maximum effect on the composition of the soil adsorption complex have been identified.

  5. Uranium leaching by fungal metabolite

    International Nuclear Information System (INIS)

    Wang Yongdong; Li Guangyue; Ding Dexin; Hu Nan

    2012-01-01

    To explore new means of bioleaching, one strain of high-yielding fungi-Aspergillus niger which could produce organic acids was separated and purified from soil samples of uranium mine. The influence of cultural temperature, initial pH value, inoculum sizes on its growth characteristics were carried out. And the tests of uranium leaching of metabolin of Aspergillus niger were operated. On these tests, the effects of metabolin of Aspergillus niger with different pH value produced in the diverse culture temperature on uranium leaching were investigated. The results show that this strain of Aspergillus niger can grow best under the following conditions: the temperature is 37℃, the initial pH value is 7.0, the inoculum sizes is 2% (the OD value of the spores solution is 0.06). The uranium extraction effects relative to the final pH value of the cultures. and the maximum leaching rates is 83.05% when the pH value is 2.3. (authors)

  6. Reduced nutrient pollution in a rural stream following septic tank upgrade and installation of runoff retention measures.

    Science.gov (United States)

    Ockenden, M C; Quinton, J N; Favaretto, N; Deasy, C; Surridge, B

    2014-07-01

    Surface water quality in the UK and much of Western Europe has improved in recent decades, in response to better point source controls and the regulation of fertilizer, manure and slurry use. However, diffuse sources of pollution, such as leaching or runoff of nutrients from agricultural fields, and micro-point sources including farmyards, manure heaps and septic tank sewerage systems, particularly systems without soil adsorption beds, are now hypothesised to contribute a significant proportion of the nutrients delivered to surface watercourses. Tackling such sources in an integrated manner is vital, if improvements in freshwater quality are to continue. In this research, we consider the combined effect of constructing small field wetlands and improving a septic tank system on stream water quality within an agricultural catchment in Cumbria, UK. Water quality in the ditch-wetland system was monitored by manual sampling at fortnightly intervals (April-October 2011 and February-October 2012), with the septic tank improvement taking place in February 2012. Reductions in nutrient concentrations were observed through the catchment, by up to 60% when considering total phosphorus (TP) entering and leaving a wetland with a long residence time. Average fluxes of TP, soluble reactive phosphorus (SRP) and ammonium-N (NH4-N) at the head of the ditch system in 2011 (before septic tank improvement) compared to 2012 (after septic tank improvement) were reduced by 28%, 9% and 37% respectively. However, TP concentration data continue to show a clear dilution with increasing flow, indicating that the system remained point source dominated even after the septic tank improvement.

  7. Effect of carbonation on the leaching of organic carbon and of copper from MSWI bottom ash.

    Science.gov (United States)

    Arickx, S; De Borger, V; Van Gerven, T; Vandecasteele, C

    2010-07-01

    In Flanders, the northern part of Belgium, about 31% of the produced amount of MSWI bottom ash is recycled as secondary raw material. In view of recycling a higher percentage of bottom ash, a particular bottom ash fraction (Ø 0.1-2mm) was studied. As the leaching of this bottom ash fraction exceeds some of the Flemish limit values for heavy metals (with Cu being the most critical), treatment is required. Natural weathering and accelerated carbonation resulted in a significant decrease of the Cu leaching. Natural weathering during 3 months caused a decrease of Cu leaching to <50% of its original value, whereas accelerated carbonation resulted in an even larger decrease (to ca. 13% of its initial value) after 2 weeks, with the main decrease taking place within the first 48 h. Total organic carbon decreased to ca. 70% and 55% of the initial concentration in the solid phase, and to 40% and 25% in the leachate after natural weathering and after accelerated carbonation, respectively. In the solid material the decrease of the Hy fraction was the largest, the FA concentration remained essentially constant. The decrease of FA in the leachate can be attributed partly to an enhanced adsorption of FA to Fe/Al (hydr)oxides, due to the combined effect of a pH decrease and the neoformation of Al (hydr)oxides (both due to carbonation). A detailed study of adsorption of FA to Fe/Al (hydr)oxides showed that significant adsorption of FA occurs, that it increases with decreasing pH and started above pH 12 for Fe (hydr)oxides and around 10 for Al (hydr)oxides. Depending whether FA or Hy are considered the controlling factor in enhanced Cu leaching, the decreasing FA or Hy in the leachate explains the decrease in the Cu leaching during carbonation. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  8. The removal of heavy metals in urban runoff by sorption on mulch

    International Nuclear Information System (INIS)

    Jang, Am; Seo, Youngwoo; Bishop, Paul L.

    2005-01-01

    A series of adsorption experiments was conducted in order to assess the ability of three mulches to remove several of the heavy metal ions typically encountered in urban runoff. Three types of mulch, cypress bark (C), hardwood bark (H), and pine bark nugget (P), were selected as potential sorbents to capture heavy metals in urban runoff. The hardwood bark (H) mulch had the best physicochemical properties for adsorption of heavy metal ions. In addition, because of its fast removal rate and acceptably high capacity for all the heavy metal ions, it was concluded that the H mulch is the best of the three adsorbents for treatment of urban runoff containing trace amounts of heavy metals. In order to investigate the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. The sorption of these metals on H mulch conformed to the linear form of the Langmuir adsorption equation. At pH 5 and 6, the Langmuir constants (S m ) for each metal were found to be 0.324 and 0.359 mmol/g (Cu); 0.306 and 0.350 mmol/g (Pb); and 0.185 and 0.187 mmol/g (Zn) at 25 deg. C. - Capsule: Hardwood bark had the best physicochemical properties for adsorption of metal ions

  9. Biocide Runoff from Building Facades

    DEFF Research Database (Denmark)

    Bollmann, Ulla E.; Fernández-Calviño, David; Brandt, Kristian K.

    2017-01-01

    Biocides are common additives in building materials. In-can and film preservatives in polymer-resin render and paint, as well as wood preservatives are used to protect facade materials from microbial spoilage. Biocides leach from the facade material with driving rain, leading to highly polluted...

  10. Bacterial leaching of waste uranium materials.

    Science.gov (United States)

    Barbic, F F; Bracilović, D M; Krajincanić, B V; Lucić, J L

    1976-01-01

    The effect of ferrobacteria and thiobacteria on the leaching of waste uranium materials from which 70-80% of uranium was previously leached by classical chemical hydrometallurgical procedure has been investigated. The bacteria used are found in the ore and the mine water of Zletovska River locality, Yugoslavia. Parameters of biological leaching were examined in the laboratory. Leaching conditions were changed with the aim of increasing the amount of uranium leached. The effect of pyrite added to the waste materials before the beginning of leaching has also been examined. Uranium leaching is directly proportional to the composition and number of ferrobacteria and thiobacteria, and increased by almost twice the value obtained from the same starting materials without using bacteria. Increased sulphuric acid concentrations stimulate considerably the rate of leaching. Uranium leaching is increased up to 20% while sulphuric acid consumption is simultaneously decreased by the addition of pyrite. Uranium concentrations in starting waste materials used for leaching were extremely low (0.0278 and 0.372% U) but about 60% recovery of uranium was obtained, with relatively low consumption of sulphuric acid.

  11. Bacterial leaching of waste uranium materials

    International Nuclear Information System (INIS)

    Barbic, F.F.; Bracilovic, D.M.; Krajincanic, B.V.; Lucic, J.L.

    1976-01-01

    The effect of ferrobacteria and thiobacteria on the leaching of waste uranium materials from which 70-80% of uranium was previously leached by classical chemical hydrometallurgical procedure has been investigated. The bacteria used are found in the ore and the mine water of Zletovska River locality, Yugoslavia. Parameters of biological leaching were examined in the laboratory. Leaching conditions were changed with the aim of increasing the amount of uranium leached. The effect of pyrite added to the waste materials before the beginning of leaching has also been examined. Uranium leaching is directly proportional to the composition and number of ferrobacteria and thiobacteria, and increased by almost twice the value obtained from the same starting materials without using bacteria. Increased sulphuric acid concentrations stimulate considerably the rate of leaching. Uranium leaching is increased up to 20% while sulphuric acid consumption is simultaneously decreased by the addition of pyrite. Uranium concentrations in starting waste materials used for leaching were extremely low (0.0278 and 0.0372% U) but about 60% recovery of uranium was obtained, with relatively low consumption of sulphuric acid. (author)

  12. Run-off from roofs

    International Nuclear Information System (INIS)

    Roed, J.

    1985-01-01

    In order to find the run-off from roof material a roof has been constructed with two different slopes (30 deg C and 45 deg C). Beryllium-7 and caesium-137 has been used as tracers. Considering new roof material the pollution removed by runoff processes has been shown to be very different for various roof materials. The pollution is much more easily removed from silicon-treated material than from porous red-tile roof material. Caesium is removed more easily than beryllium. The content of caesium in old roof materials is greater in red-tile than in other less-porous materials. However, the measured removal from new material does not correspond to the amount accumulated in the old. This could be explained by weathering and by saturation effects. This last effect is probably the more important. The measurements on old material indicates a removal of 44-86% of the caesium pollution by run-off, whereas the measurement on new showed a removal of only 31-50%. It has been demonstrated that the pollution concentration in the run-off water could be very different from that in rainwater. The work was part of the EEC Radiation Protection Programme and done under a subcontract with Association Euratom-C.E.A. No. SC-014-BIO-F-423-DK(SD) under contract No. BIO-F-423-81-F. (author)

  13. Spot Spraying Reduces Herbicide Concentrations in Runoff.

    Science.gov (United States)

    Melland, Alice R; Silburn, D Mark; McHugh, Allen D; Fillols, Emilie; Rojas-Ponce, Samuel; Baillie, Craig; Lewis, Stephen

    2016-05-25

    Rainfall simulator trials were conducted on sugar cane paddocks across dry-tropical and subtropical Queensland, Australia, to examine the potential for spot spraying to reduce herbicide losses in runoff. Recommended rates of the herbicides glyphosate, 2,4-D, fluoroxypyr, atrazine, and diuron were sprayed onto 0, 20, 40, 50, 70, or 100% of the area of runoff plots. Simulated rainfall was applied 2 days after spraying to induce runoff at one plant cane and three ratoon crop sites. Over 50% of all herbicides were transported in the dissolved phase of runoff, regardless of the herbicide's sediment-water partition coefficient. For most sites and herbicides, runoff herbicide concentrations decreased with decreasing spray coverage and with decreasing herbicide load in the soil and cane residues. Importantly, sites with higher infiltration prior to runoff and lower total runoff had lower runoff herbicide concentrations.

  14. Application of percolation leaching in Fuzhou uranium mine

    International Nuclear Information System (INIS)

    Jiang Lang; Wang Haita; He Jiangming

    2006-01-01

    In order to solve these problems such as high cost by conventional agitation leaching, low permeability and low leaching rate by heap leach, a percolation leaching method was developed. Two-year's production results show that leaching rate of uranium is up to 90% by this method. Compared with conventional agitation leaching, the power, sulfuric acid and lime consumption by the percolation leaching decreased by 60%, 27% and 77% respectively. (authors)

  15. The structure of leached sodium borosilicate glass

    International Nuclear Information System (INIS)

    Bunker, B.C.; Tallant, D.R.; Headley, T.J.; Turner, G.L.; Kirkpatrick, R.J.

    1988-01-01

    Raman spectroscopy, solid state 29 Si, 11 B, 17 O, and 23 Na nuclear magnetic resonance spectroscopy, and transmission electron microscopy have been used to investigate how the structures of sodium borosilicate glasses change during leaching in water at pH 1, 9, and 12. Results show that the random network structure present prior to leaching is transformed into a network of small condensed ring structures and/or colloidal silica particles. The restructuring of leached glass can be rationalised on the basis of simple hydrolysis (depolymerisation) and condensation (repolymerisation) reactions involving Si-O-Si and Si-O-B bonds. The structural changes that occur during leaching influence the properties of the leached layer, including leaching kinetics, crazing and spalling, and slow crack growth. (author)

  16. The Danish Pesticide Leaching Assessment Programme

    DEFF Research Database (Denmark)

    Rosenbom, Annette Elisabeth; Brüsch, Walter Michael; Juhler, Rene K.

    In 1998, the Danish Parliament initiated the Pesticide Leaching Assessment Programme (PLAP), an intensive monitoring programme aimed at evaluating the leaching risk of pesticides under field conditions. The objective of the PLAP is to improve the scientific foundation for decision......-making in the Danish regulation of pesticides. The specific aim is to analyse whether pesticides applied in accordance with current regulations leach to groundwater in unacceptable concentrations. The programme currently evaluates the leaching risk of 41 pesticides and 40 degradation products at five agricultural......, thiamethoxam, tribenuronmethyl, and triasulfuron) did not leach during the 1999-2009 monitoring period. 13 of the applied pesticides exhibited pronounced leaching of the pesticide and/or their degradation product(-s) 1 m b.g.s. in yearly average concentrations exceeding 0.1 μg/l (maximum allowable...

  17. Modelling phosphate adsorption to the soil: Application of the non-ideal competitive adsorption model

    International Nuclear Information System (INIS)

    Abou Nohra, Joumana S.; Madramootoo, Chandra A.; Hendershot, William H.

    2007-01-01

    Phosphorus (P) transport in subsurface runoff has increased despite the limited mobility of P in soils. This study investigated the ability of the non-ideal competitive adsorption (NICA) model to describe phosphate (PO 4 ) adsorption for soils in southern Quebec (Canada). We measured the surface charge and PO 4 adsorption capacity for 11 agricultural soils. Using the experimental data and a nonlinear fitting function, we derived the NICA model parameters. We found that the NICA model described accurately the surface charge of these soils with a mean R 2 > 0.99, and described the adsorption data with a mean R 2 = 0.96. We also found that the variable surface charge was distributed over the two binding sites with the low pH sites demonstrating a stronger binding energy for hydroxyl and PO 4 ions. We established that the NICA model is able to describe P adsorption for the soils considered in this study. - The NICA model accurately described the adsorption of phosphate to some southern Quebec soils

  18. The leaching characteristics of vitrified slag

    International Nuclear Information System (INIS)

    Zhang, Jinlong; Li, Yaojian; Tian, Junguo; Sheng, Hongzhi; Xu, Yongxiang

    2010-01-01

    Full Text: Plasma-arc technology was developed to fix the heavy metal of flying ash by the Institute of Mechanics, Chinese Academy of Sciences (CAS-IMECH). A direct current (DC) experimental facility of 30 kW with plasma-arc technology was setup to form vitrified slag. The additives (CaO, SiO 2 ) were added into the reactor to form vitrified slag and fix the heavy metal (Cr, Pb), under dissimilar condition (long and short heating-up time, natural and water cooling). Vitrified slag was broken into different particle size, from 0.1 mm to 1 cm. The particles with different specific surface area were used to study the leaching of heavy metals in vitrified slag rate of speed. The pH value of leaching solution are from 2 to 12, the experiment was kept at different external temperature, from 4 degree Celsius to 70 degree celsius, for 1 week to 1 month. Heavy metal leaching concentration was used to measure the chemical stability of vitrified slag. The results show that the higher specific surface area, the higher heavy metal leaching concentration, but when the specific surface area reaches a certain value, little change in leaching concentration. The impact of temperature on leaching concentration was not significant, from 4 degree Celsius to 70 degree Celsius. The leaching concentration increases with decreasing of the pH value of leaching solution when the pH value of leaching solution less than 7, and little change in concentration increases with pH value when the pH value of leaching solution more than 7. Compared with the leaching concentration after 1 month, the leaching concentration after 1 week has not changed significantly. (Author)

  19. Mobilization and distribution of lead originating from roof dust and wet deposition in a roof runoff system.

    Science.gov (United States)

    Yu, Jianghua; Yu, Haixia; Huang, Xiaogu

    2015-12-01

    In this research, the mobilization and distribution of lead originating in roof dust and wet deposition were investigated within a roof dust-rooftop-runoff system. The results indicated that lead from roof dust and wet deposition showed different transport dynamics in runoff system and that this process was significantly influenced by the rainfall intensity. Lead present in the roof dust could be easily washed off into the runoff, and nearly 60 % of the total lead content was present in particulate form. Most of the lead from the roof dust was transported during the late period of rainfall; however, the lead concentration was higher for several minutes at the rainfall beginning. Even though some of the lead from wet deposition, simulated with a standard isotope substance, was adsorbed onto adhered roof dust and/or retained on rooftop in runoff system, most of it (50-82 %) remained as dissolved lead in the runoff for rainfall events of varying intensity. Regarding the distribution of lead in the runoff system, the results indicated that it could be carried in the runoff in dissolved and particulate form, be adsorbed to adhered roof dust, or remain on the rooftop because of adsorption to the roof material. Lead from the different sources showed different distribution patterns that were also related to the rainfall intensity. Higher rainfall intensity resulted in a higher proportion of lead in the runoff and a lower proportion of lead remaining on the rooftop.

  20. Removal of metals from industrial wastewater and urban runoff by mineral and bio-based sorbents.

    Science.gov (United States)

    Gogoi, Harshita; Leiviskä, Tiina; Heiderscheidt, Elisangela; Postila, Heini; Tanskanen, Juha

    2018-03-01

    The study was performed to evaluate chemically modified biosorbents, hydrochloric acid treated peat (HCl-P) and citric acid treated sawdust (Citric acid-SD) for their metal removal capacity from dilute industrial wastewater and urban runoff and compare their efficiency with that of commercially available mineral sorbents (AQM PalPower M10 and AQM PalPower T5M5 magnetite). Batch and column experiments were conducted using real water samples to assess the sorbents' metal sorption capacity. AQM PalPower M10 (consisting mainly of magnesium, iron and silicon oxides) exhibited excellent Zn removal from both industrial wastewater and spiked runoff water samples even at low dosages (0.1 g/L and 0.05 g/L, respectively). The high degree of Zn removal was associated with the release of hydroxyl ions from the sorbent and subsequent precipitation of zinc hydroxide. The biosorbents removed Ni and Cr better than AQM PalPower M10 from industrial wastewater and performed well in removing Cr and Cu from spiked runoff water, although at higher dosages (0.3-0.75 g/L). The main mechanism of sorption by biosorbents was ion exchange. The sorbents required a short contact time to reach equilibrium (15-30 min) in both tested water samples. AQM PalPower T5M5 magnetite was the worst performing sorbent, leaching Zn into both industrial and runoff water and Ni into runoff water. Column tests revealed that both HCl-P and AQM PalPower M10 were able to remove metals, although some leaching was witnessed, especially As from AQM PalPower M10. The low hydraulic conductivity observed for HCl-P may restrict the possibilities of using such small particle size peat material in a filter-type passive system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A New Generation of Leaching Tests – The Leaching Environmental Assessment Framework

    Science.gov (United States)

    Provides an overview of newly released leaching tests that provide a more accurate source term when estimating environmental release of metals and other constituents of potential concern (COPCs). The Leaching Environmental Assessment Framework (LEAF) methods have been (1) develo...

  2. URANIUM LEACHING AND RECOVERY PROCESS

    Science.gov (United States)

    McClaine, L.A.

    1959-08-18

    A process is described for recovering uranium from carbonate leach solutions by precipitating uranium as a mixed oxidation state compound. Uranium is recovered by adding a quadrivalent uranium carbon;te solution to the carbonate solution, adjusting the pH to 13 or greater, and precipitating the uranium as a filterable mixed oxidation state compound. In the event vanadium occurs with the uranium, the vanadium is unaffected by the uranium precipitation step and remains in the carbonate solution. The uranium-free solution is electrolyzed in the cathode compartment of a mercury cathode diaphragm cell to reduce and precipitate the vanadium.

  3. Uranium extraction history using pressure leaching

    International Nuclear Information System (INIS)

    Fraser, K.S.; Thomas, K.G.

    2010-01-01

    Over the past 60 years of uranium process development only a few commercial uranium plants have adopted a pressure leaching process in their flowsheet. The selection of acid versus alkaline pressure leaching is related to the uranium and gangue mineralogy. Tetravalent (U"+"4) uranium has to be oxidized to hexavalent (U"+"6) uranium to be soluble. Refractory tetravalent uranium requires higher temperature and pressure, as practised in pressure leaching, for conversation to soluble hexavalent uranium. This paper chronicles the history of these uranium pressure leaching facilities over the past 60 years, with specific details of each design and operation. (author)

  4. A new Leaching System, Sheta Extractor

    International Nuclear Information System (INIS)

    Sheta, M.E.

    2008-01-01

    Moving of crushed solid ores against leaching solution in a continuous countercurrent arises a true technical problem. This invented system introduces a practical solution for such problem. Inside the system, the crushed ore is driving against gravity, whereas the leaching solution moves in the opposite direction. Contact between the two phases occurs with gentle stirring. After contact, discharging of the processed phases takes place automatically out the system. The system was investigated for uranium leaching from a coarse grained fraction (+2 --- -- -30 mm) of uranium mineralized granite sample. Uranium leaching percent reached to nearly 50% using sulfuric acid

  5. Heap leaching procedure for the Uranium extraction

    International Nuclear Information System (INIS)

    Shishahbore, M. R.

    2002-01-01

    Heap leaching of Uranium ores is currently in use in several countries. Before taking any decision for construction of heap in industrial scale, it is necessary to obtain the main factors that influence the heap leaching process, such as acid construction, acid solution flowrate, temperature of reaction, or size, ration of liquid to solid, permeability and suitable oxidant. To achieve the above parameters, small scale column leaching is usually recommended. In this project column leaching were carried out in 6 plexiglass column with 43.5 cm an height and 7.4 cm inner diameter. In each column closely 2.00 kg Uranium ore were leached by sulfuric acid. Leaching operation on Iranian ores from two different anomalies from the same area were investigated. In this project, six column were leached at different flowrate of eluent and effect of oxidant were investigated. Acid consumption were in the range of 60 - 144 kg per ton ore and recovery between 73.07% - 99.97%. Finally according to the results obtained, investigated that over are suitable to heap leaching technique. Al tough, to enforce of heap leaching project need to more experiments

  6. Method of continuous pressure leaching of ores

    International Nuclear Information System (INIS)

    Fiala, P.; Baloun, S.; Polansky, M.

    1987-01-01

    Ore leaching, especially suspensions of ground ore or fine ore fractions from physical treatment was divided into two operations. The former, i.e., ore mixing with technical grade concentrated sulfuric acid proceeded in a separate mixer. The mixture was then transported into an autoclave where the actual leaching proceeded for 2 to 4 hours. The extracted mixture was discharged through the autoclave bottom. The leaching autoclave used can be without any inner structures. The separation of mixing from the actual leaching allows processing ores with high levels of clay components, increasing operating reliability of the facility, reducing consumption of special structural materials and energy, and increasing process efficiency. (E.S.)

  7. Impact of peatland restoration on nutrient and carbon leaching from contrasting sites in southern Finland

    Science.gov (United States)

    Vasander, Harri; Sallantaus, Tapani; Koskinen, Markku

    2010-05-01

    Impacts of peatland restoration on nutrient and carbon leaching from contrasting sites in southern Finland Tapani Sallantaus1, Markku Koskinen2, Harri Vasander2 1)Finnish Environment Institute, Biodiversity unit, Box 140, FIN-00251 Helsinki, Finland, tapani.sallantaus@ymparisto.fi 2)Department of Forest Sciences, University of Helsinki, Box 27, FIN-00014 University of Helsinki, Finland, markku.koskinen@helsinki.fi, harri.vasander@helsinki.fi Less than 20 % of the original mire area of southern Finland is still in natural state. Even many peatlands in today's nature conservation areas had been partly or totally drained before conservation. Until now, about 15000 ha of peatlands have been restored in conservation areas. Here we present data concerning changes in leaching due to restoration in two contrasting areas in southern Finland. The peatlands in Seitseminen have originally been fairly open, growing stunted pine, and unfertile, either bogs or poor fens. The responses of tree stand to drainage in the 1960s were moderate, and the tree stand before restoration was about 50 m3/ha, on average. The trees were partly harvested before filling in the ditches mainly in the years 1997-1999 . The peatlands of Nuuksio are much more fertile than those in Seitseminen, and had greatly responded to drainage, which took place already in the 1930s and 1950s. The tree stand consisted mainly of spruce and exceeded 300 m3/ha in large part of the area. The ditches were dammed in the autumn 2001 and the tree stand was left standing. Runoff water quality was monitored in three basins in both areas. To obtain the leaching rates, we used simulated runoff data obtained from the Finnish Environment Institute, Hydrological Services Division. The responses in leaching were in the same direction in both cases. However, especially when calculated per restored hectare (Table 1), the responses were much stronger in the more fertile areas of Nuuksio for organic carbon and nitrogen, but not so much

  8. Investigation of a precise static leach test for the testing of simulated nuclear waste materials

    International Nuclear Information System (INIS)

    Kingston, H.M.; Cronin, D.J.; Epstein, M.S.

    1984-01-01

    The precision of the nuclear waste static leach test was evaluated using controlled experimental conditions and homogeneous glass materials. The majority of the leachate components were subjected to simultaneous multielement DCP analysis. The overall precision of the static leach test is determined by the summation of random effects caused by: variance in the experimental conditions of the leaching procedure; inhomogeneity of the material to be leached; and variance of the analytical techniques used to determine elemental concentrations in the leachate. In this study, strict control of key experimental parameters was employed to reduce the first source of variance. In addition, special attention to the preparation of glass samples to be tested assured a high degree of homogeneity. Described here are the details of the reduction of these two sources of variance to a point where the overall test precision is limited by that of the analysis step. Of the elements determined - B, Ba, Ca, Cs, Mo, Na, Si, Sr, and Zn - only Ca and Zn exhibited replicate imprecision significantly greater than that observed in the analysis of the leachate solutions. The imprecision in the Zn was partially attributed to the non-reproducible adsorption onto the leach vessel walls during the 28 day test period. None of the other elements exhibited this behavior

  9. Retention and leaching of nitrite by municipal solid waste incinerator bottom ash under the landfill circumstance.

    Science.gov (United States)

    Yao, Jun; Kong, Qingna; Zhu, Huayue; Long, Yuyang; Shen, Dongsheng

    2015-01-01

    The retention and leaching of nitrite by municipal solid waste incinerator (MSWI) bottom ash could affect its migration in the landfill. In this study, the effect of the dosage of MSWI bottom ash as well as the variation of the landfill environmental parameters including pH, anions and organic matter on the nitrite retention and leaching behavior was investigated by batch experiments. The highest removal percentage (73.0%) of nitrite was observed when the dosage of MSWI bottom ash was 10 g L(-1) in 2 mg L(-1) nitrite solution. Further increase of the dosage would retard the retention, as the nitrite leaching from MSWI bottom ash was enhanced. The optimum retention of nitrite was observed when the pH was 5.0, while the leaching of nitrite showed a consistent reduction with the increase of pH. Besides, the presence of Cl(-), SO4(2)(-) and acetic acid could enhance the leaching of nitrite and mitigate the retention process. However, the retention of nitrite was enhanced by PO4(3)(-), which was probably due to the formation of the apatite, an active material for the adsorption of the nitrite. These results suggested that MSWI bottom ash could affect the migration of nitrite in the landfill, which was related to the variation of the landfill circumstance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Effects of mechanical harvest plus chipping and prescribed fire on Sierran runoff water quality.

    Science.gov (United States)

    Loupe, T M; Miller, W W; Johnson, D W; Sedinger, J S; Carroll, E M; Walker, R F; Murphy, J D; Stein, C M

    2009-01-01

    Fire suppression in Sierran ecosystems creates a substantial wildfire hazard and may exacerbate nutrient inputs into Lake Tahoe by allowing the buildup of O horizon material, which serves as a source for high N and P concentrations in runoff water. The purpose of this study was to evaluate the effects of biomass reduction using cut-to-length mechanical harvest followed by chipping and controlled burning on surface runoff volume and water quality. Based on previous findings regarding N and P leaching flux and soil solution concentrations, we hypothesized that controlled burning and/or mechanical harvest with residue chipping does not increase inorganic N, P, and S concentrations in overland flow. Runoff, snowmelt, and rainfall were collected, volume measurements were taken, and samples were analyzed for NO(3)-N, NH(4)-N, PO(4)-P, and SO(4). Runoff volume, season, and year were identified as important parameters influencing overland flow nutrient concentrations and loads. Higher nutrient concentrations were commonly associated with summer rather than winter runoff, but the opposite was true for nutrient loads due to the higher runoff volumes. Treatment (unharvested, harvested, unburned, burned) effect was a strong predictor for discharge loads of NO(3)-N and SO(4) but was a weak predictor for PO(4)-P. Discharge loads of NO(3)-N and SO(4) were greater for the unburned harvested and the burned unharvested treatments than for the unburned, unharvested control sites or the burned and harvested combined treatment. Although mechanical harvest and/or controlled burning had a small initial impact on increased nutrient loading, the effects were minimal compared with background levels. Hence, these management practices may have the potential to improve forest health without the danger of large-magnitude nutrient mobilization and degradation of runoff water quality found with wildfire.

  11. Potential for leaching of arsenic from excavated rock after different drying treatments.

    Science.gov (United States)

    Li, Jining; Kosugi, Tomoya; Riya, Shohei; Hashimoto, Yohey; Hou, Hong; Terada, Akihiko; Hosomi, Masaaki

    2016-07-01

    Leaching of arsenic (As) from excavated rock subjected to different drying methods is compared using sequential leaching tests and rapid small-scale column tests combined with a sequential extraction procedure. Although the total As content in the rock was low (8.81 mg kg(-1)), its resulting concentration in the leachate when leached at a liquid-to-solid ratio of 10 L kg(-1) exceeded the environmental standard (10 μg L(-1)). As existed mainly in dissolved forms in the leachates. All of the drying procedures applied in this study increased the leaching of As, with freeze-drying leading to the largest increase. Water extraction of As using the two tests showed different leaching behaviors as a function of the liquid-to-solid ratio, and achieved average extractions of up to 35.7% and 25.8% total As, respectively. Dissolution of As from the mineral surfaces and subsequent re-adsorption controlled the short-term release of As; dissolution of Fe, Al, and dissolved organic carbon played important roles in long-term As leaching. Results of the sequential extraction procedure showed that use of 0.05 M (NH4)2SO4 underestimates the readily soluble As. Long-term water extraction removed almost all of the non-specifically sorbed As and most of the specifically sorbed As. The concept of pollution potential indices, which are easily determined by the sequential leaching test, is proposed in this study and is considered for possible use in assessing efficacy of treatment of excavated rocks. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Time focused measurements of roof runoff quality

    International Nuclear Information System (INIS)

    Schriewer, A.; Horn, H.; Helmreich, B.

    2008-01-01

    Runoff properties and their changes during runoff of a 14 year old zinc roof were investigated. Zinc, lead, cadmium, pH value, rain intensity and electric conductivity have been measured for a period of one year. A runoff rate of 3.73 g/m 2 a and a volume weighted mean zinc concentration of 4.9 mg/L were determined. First flush behaviour was observed in 93% of runoff events. Low rain intensities are correlating with higher zinc concentrations in runoff, whereas the duration of antecedent dry periods could not directly be linked with initial zinc concentrations

  13. Adsorption of sugar beet herbicides to Finnish soils.

    Science.gov (United States)

    Autio, Sari; Siimes, Katri; Laitinen, Pirkko; Rämö, Sari; Oinonen, Seija; Eronen, Liisa

    2004-04-01

    Three sugar beet herbicides, ethofumesate, phenmedipham and metamitron, are currently used on conventional sugar beet cultivation, while new varieties of herbicide resistant (HR) sugar beet, tolerant of glyphosate or glufosinate-ammonium, are under field testing in Finland. Little knowledge has so far been available on the adsorption of these herbicides to Finnish soils. The adsorption of these five herbicides was studied using the batch equilibrium method in 21 soil samples collected from different depths. Soil properties like organic carbon content, texture, pH and partly the phosphorus and oxide content of the soils were tested against the adsorption coefficients of the herbicides. In general, the herbicides studied could be arranged according to their adsorption coefficients as follows: glyphosate>phenmedipham>ethofumesate approximately glufosinate-ammonium>metamitron, metamitron meaning the highest risk of leaching. None of the measured soil parameters could alone explain the adsorption mechanism of these five herbicides. The results can be used in model assessments of risk for leaching to ground water resulting from weed control of sugar beet in Finland.

  14. Understanding the factors influencing the removal of heavy metals in urban stormwater runoff.

    Science.gov (United States)

    Maniquiz-Redillas, Marla C; Kim, Lee-Hyung

    2016-01-01

    In this research, an infiltration trench equipped with an extensive pretreatment and filter bed consisting of woodchip, sand and gravel was utilized as a low impact development technique to manage stormwater runoff from a highly impervious road with particular emphasis on heavy metal removal. Findings revealed that the major factors influencing the removal of heavy metals were the concentration of the particulate matters and heavy metals in runoff, runoff volume and flow rates. The reduction of heavy metals was enhanced by sedimentation of particulates through pretreatment. Fine particles (heavy metals, thus, enhanced adsorption and filtration using various filter media were important design considerations. Sediment was most highly attached on the surface area of woodchip than to other filter media like sand, gravel and geotextile. It is suggested that maintenance must be performed after the end of the winter season wherein high sediment rate was observed to maintain the efficiency of the treatment system.

  15. Sediment Enrichment Ratio and Nutrient Leached by Runoff and Soil Erosion on Cacao Plantation

    Directory of Open Access Journals (Sweden)

    Oteng Haridjaja

    2012-01-01

    Full Text Available Soil consevation management system is an activity for diminishing sediment enrichment ratio and nutrient leachedsby water run off and soil erosion processes. The research was aimed to study sediment enrichment ratio and nutrientleached by run off and soil erosion on cacao plantations. Arachis pintoi with strips parallel contour and multiplestrip cropping of upland rice or soybean (Glycine max were planted to improve soil physical characterictic oncacao plantation as a main plant. The expriment were conducted with treatments as 10-15% and 40-45% slopes, 5-7months and 25-27 months cacao ages (as main plants. As sub plots are T1 as a monoculture which to be cleaningunder the plant canopy, T2 as a multiple strip cropping of upland rice or soybean, T3 as a combination of T2 and A.Pintoi strip. The results showed that total N, P2O5, and K2O and organic-C contents in water run off and soilsediments indicated that T3 >T2 >T1 treatment, with the contents of each nutrient: T3 (total N 0.18%; 24.87 mg 100g-1 P2O5: K2O 15.16 mg 100 g-1, T1 (total N 0.16%, 22.39 mg 100g-1 P2O5, K2O 11.50 mg 100g-1. The total N, P2O5, K2Oand organic-C soil contents 1.

  16. Transport and solubility of Hetero-disperse dry deposition particulate matter subject to urban source area rainfall-runoff processes

    Science.gov (United States)

    Ying, G.; Sansalone, J.

    2010-03-01

    SummaryWith respect to hydrologic processes, the impervious pavement interface significantly alters relationships between rainfall and runoff. Commensurate with alteration of hydrologic processes the pavement also facilitates transport and solubility of dry deposition particulate matter (PM) in runoff. This study examines dry depositional flux rates, granulometric modification by runoff transport, as well as generation of total dissolved solids (TDS), alkalinity and conductivity in source area runoff resulting from PM solubility. PM is collected from a paved source area transportation corridor (I-10) in Baton Rouge, Louisiana encompassing 17 dry deposition and 8 runoff events. The mass-based granulometric particle size distribution (PSD) is measured and modeled through a cumulative gamma function, while PM surface area distributions across the PSD follow a log-normal distribution. Dry deposition flux rates are modeled as separate first-order exponential functions of previous dry hours (PDH) for PM and suspended, settleable and sediment fractions. When trans-located from dry deposition into runoff, PSDs are modified, with a d50m decreasing from 331 to 14 μm after transport and 60 min of settling. Solubility experiments as a function of pH, contact time and particle size using source area rainfall generate constitutive models to reproduce pH, alkalinity, TDS and alkalinity for historical events. Equilibrium pH, alkalinity and TDS are strongly influenced by particle size and contact times. The constitutive leaching models are combined with measured PSDs from a series of rainfall-runoff events to demonstrate that the model results replicate alkalinity and TDS in runoff from the subject watershed. Results illustrate the granulometry of dry deposition PM, modification of PSDs along the drainage pathway, and the role of PM solubility for generation of TDS, alkalinity and conductivity in urban source area rainfall-runoff.

  17. Study on Leaching of Hexavalent Chromium from Hardened Concretes Using Tank Leaching Test

    OpenAIRE

    Takahashi, Shigeru; Sakai, Etsuo; Sugiyama, Takafumi

    2007-01-01

    Tank leaching tests were carried out to investigate the behavior of leaching trace elements from monolith samples. This study consists of two series, and the trace element used was hexavalent chromium. In Series I, the influence of the leachant/surface area of the specimen (L/S ratio) on the leaching amount was investigated. The leaching amount was found to increase with the amount of worked water. This shows that any L/S ratio can be selected in the tank leaching test. In Series II, th...

  18. Successful trials on pressure leaching of uranium

    International Nuclear Information System (INIS)

    Pendreigh, R.

    1978-01-01

    High pressure leaching can increase uranium extraction from some low grade ores by ten per cent, and Anglo American Corporation's eighteen months of pilot plant tests point the way to commercial application. Interest in pressure leaching of uranium has been renewed with the recent increase in uranium and gold prices and costs of reagents

  19. Optimizing conditions for an accelerated leach test

    International Nuclear Information System (INIS)

    Pietrzak, R.F.; Fuhrmann, M.; Heiser, J.; Franz, E.M.; Colombo, P.

    1988-01-01

    An accelerated leach test for low-level radioactive waste forms is being developed to provide, in a short time, data that can be extrapolated to long time periods. The approach is to provide experimental conditions that will accelerate leaching without changing the dominant release mechanism. Experimental efforts have focused on combining individual factors that have been observed to accelerate leaching. These include elevated temperature, increased leachant volume, and reduced specimen size. The response of diffusion coefficients to various acceleration factors have been evaluated and provide information on experimental parameters that need to be optimized to increase leach rates. Preliminary modeling using a diffusion mechanism (allowing for depletion) of a finite cylinder geometry indicates that during early portions of experiments (daily sampling intervals), leaching is diffusion controlled and more rapid than later in the same experiments (weekly or greater sampling intervals). For cement waste forms, this reduction in rate may be partially controlled by changes in physical structure and chemistry (sometimes related to environmental influences such as CO 2 ), but it is more likely associated with the duration of the sampling interval. By using a combination of mathematical modeling and by experimentally investigating various leach rate controlling factors, a more complete understanding of leaching processes is being developed. This, in turn, is leading to optimized accelerating conditions for a leach test

  20. Optimizing conditions for an accelerated leach test

    International Nuclear Information System (INIS)

    Pietrzak, R.F.; Fuhrmann, M.; Heiser, J.; Franz, E.M.; Colombo, P.

    1988-01-01

    An accelerated leach test for low-level radioactive waste forms is being developed to provide, in a short time, data that can be extrapolated to long time periods. The approach is to provide experimental conditions that will accelerate leaching without changing the dominant release mechanism. Experimental efforts have focused on combining individual factors that have been observed to accelerate leaching. These include elevated temperature, increased leachant volume, and reduced specimen size. The response of diffusion coefficients to various acceleration factors have been evaluated and provide information on experimental parameters that need to be optimized to increase leach rates. For example, these data show that large volumes of leachant are required when leaching portland cement waste forms at elevated temperatures because of high concentrations of dissolved species. Sr-85 leaching is particularly susceptible to suppression due to concentration effects while Cs-137 leaching is less so. Preliminary modeling using a diffusion mechanism (allowing for depletion) of a finite cylinder geometry indicates that during early portions of experiments (daily sampling intervals), leaching is diffusion controlled and more rapid than later in the same experiments (weekly or greater sampling intervals). For cement waste forms, this reduction in rate may be partially controlled by changes in physical structure and chemistry (sometimes related to environmental influences such as CO 2 ), but it is more likely associated with the duration of the sampling interval. 9 refs., 6 figs

  1. PRESERVATIVE LEACHING FROM WEATHERED CCA-TREATED WOOD

    Science.gov (United States)

    Disposal of discarded CCA-treated wood in landfills raises concerns with respect to leaching of preservative compounds. When unweathered CCA-treated wood is leached using the toxicity characteristic leaching procedure (TCLP), arsenic concentrations exceed the toxicity characteris...

  2. Leaching of heavy metals from steelmaking slags

    International Nuclear Information System (INIS)

    Gomez, J. F. P.; Pino, C. G.

    2006-01-01

    Leaching tests with EAF and Ladle slags were performed, using a flow through tests and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. the chemical analysis of the leachates during this period shows, in general, for both types of slag, and increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slang samples submitted to these trials presented very low total leaching levels. The most extracted elements are calcium and magnesium. Nevertheless, in flow-though test, calcium and magnesium leached from solid slags are below 0.5% and all other metals below 0.1%. Leachates obtained with DIN 38414-S4 present, as expected, higher leaching values; however, these are inferior to 5% (Ca) and 1% (other elements). (Author) 12 refs

  3. Leaching behavior of solidified plastics radioactive wastes

    International Nuclear Information System (INIS)

    Yook, Chong Chul; Lee, Byung Hun; Jae, Won Mok; Kim, Kyung Eung

    1986-01-01

    It is highly needed to develope the solidification process to dispose safely the radioactive wastes increasing with the growth of the nuclear industry. The leaching mechanisms of the solidified plastic wastes were investigated and the leaching rates of the plastic wastes were also measured among the many solidification processes. In addition, the transport equation based on the diffusion or the diffusion-dissolution was compared with the empirical equation derived from the experimental data by graphical method. Consequently, leaching process of the solidified plastic wastes is quite well agreed with the mass transport theory, but it may be difficult to simulate leaching process by diffusion dissolution mechanism. But the theoretical equation could be applicable to the cumulative amount of radionuclides leached form the plastic wastes disposed into the environment. (Author)

  4. Leaching of tritium from a cement composite

    International Nuclear Information System (INIS)

    Matsuzuru, Hideo; Ito, Akihiko

    1978-10-01

    Leaching of tritium from cement composites into an aqueous phase has been studied to evaluate the safety of incorporation of the tritiated liquid waste into cement. Leaching tests were performed by the method recommended by the International Atomic Energy Agency. The Leaching fraction was measured as functions of waste-cement ratio (Wa/C), temperature of leachant and curing time. The tritium leachability of cement in the long term test follows the order: alumina cement portland cement slag cement. The fraction of tritium leached increases with increasing Wa/C and temperature and decreasing curing period. A deionized water as a leachant gives a slightly higher leachability than synthetic sea water. The amount leached of tritium from a 200 l drum size specimen was estimated on the basis of the above results. (author)

  5. Bacteria heap leaching test of a uranium ore

    International Nuclear Information System (INIS)

    Liu Hui; Liu Jinhui; Wu Weirong; Han Wei

    2008-01-01

    Column bioleaching test of a uranium ore was carried out. The optimum acidity, spraying intensity, spray-pause time ratio were determined. The potential, Fe and U concentrations in the leaching process were investigated. The effect of bacteria column leaching was compared with that of acid column leaching. The results show that bacteria column leaching can shorten leaching cycle, and the leaching rate of uranium increases by 9.7%. (authors)

  6. Long-term leach rates of glasses containing actual waste

    International Nuclear Information System (INIS)

    Wiley, J.R.; LeRoy, J.H.

    1979-01-01

    Leach rates of borosilicate glasses that contained actual Savannah River Plant waste were measured. Leaching was done by water and by buffer solutions of pH 4, 7, and 9. Leach rates were then determined from the amount of 137 Cs, 90 Sr, and Pu released into the leach solutions. The cumulative fractions leached were fit to a mathematical model that included leaching by diffusion and glass dissolution

  7. Long-term leach rates of glasses containing actual waste

    International Nuclear Information System (INIS)

    Wiley, J.R.; LeRoy, J.H.

    1979-01-01

    Leach rates of borosilicate glasses that contained actual Savannah River Plant waste were measured. Leaching was done by water and by buffer solutions of pH 4, 7, and 9. Leach rates were then determined from the amount of 137 Cs, 90 Sr, and plutonium released into the leach solutions. The cumulative fractions leached were fit to a mathematical model that included leaching by diffusion and glass dissolution. 5 figures, 3 tables

  8. Dynamic leaching test of personal computer components.

    Science.gov (United States)

    Li, Yadong; Richardson, Jay B; Niu, Xiaojun; Jackson, Ollie J; Laster, Jeremy D; Walker, Aaron K

    2009-11-15

    A dynamic leaching test (DLT) was developed and used to evaluate the leaching of toxic substances for electronic waste in the environment. The major components in personal computers (PCs) including motherboards, hard disc drives, floppy disc drives, and compact disc drives were tested. The tests lasted for 2 years for motherboards and 1.5 year for the disc drives. The extraction fluids for the standard toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) were used as the DLT leaching solutions. A total of 18 elements including Ag, Al, As, Au, Ba, Be, Cd, Cr, Cu, Fe, Ga, Ni, Pd, Pb, Sb, Se, Sn, and Zn were analyzed in the DLT leachates. Only Al, Cu, Fe, Ni, Pb, and Zn were commonly found in the DLT leachates of the PC components. Their leaching levels were much higher in TCLP extraction fluid than in SPLP extraction fluid. The toxic heavy metal Pb was found to continuously leach out of the components over the entire test periods. The cumulative amounts of Pb leached out of the motherboards in TCLP extraction fluid reached 2.0 g per motherboard over the 2-year test period, and that in SPLP extraction fluid were 75-90% less. The leaching rates or levels of Pb were largely affected by the content of galvanized steel in the PC components. The higher was the steel content, the lower the Pb leaching rate would be. The findings suggest that the obsolete PCs disposed of in landfills or discarded in the environment continuously release Pb for years when subjected to landfill leachate or rains.

  9. Effect of accelerated carbonation and zero valent iron on metal leaching from bottom ash.

    Science.gov (United States)

    Nilsson, M; Andreas, L; Lagerkvist, A

    2016-05-01

    About 85% of the ashes produced in Sweden originated from the incineration of municipal solid waste and biofuel. The rest comes from the thermal treatment of recycled wood, peat, charcoal and others. About 68% of all ashes annually produced in Sweden are used for constructions on landfills, mainly slopes, roads and embankments, and only 3% for construction of roads and working surfaces outside the landfills (SCB, 2013). Since waste bottom ash (BA) often has similar properties to crushed bedrock or gravel, it could be used for road constructions to a larger extent. However, the leaching of e.g. Cr, Cu, Mo, Pb and Zn can cause a threat to the surrounding environment if the material is used as it is. Carbonation is a commonly used pre-treatment method, yet it is not always sufficient. As leaching from aged ash is often controlled by adsorption to iron oxides, increasing the number of Fe oxide sorption sites can be a way to control the leaching of several critical elements. The importance of iron oxides as sorption sites for metals is known from both mineralogical studies of bottom ash and from the remediation of contaminated soil, where iron is used as an amendment. In this study, zero valent iron (Fe(0)) was added prior to accelerated carbonation in order to increase the number of adsorption sites for metals and thereby reduce leaching. Batch, column and pHstat leaching tests were performed and the leaching behaviour was evaluated with multivariate data analysis. It showed that leaching changed distinctly after the tested treatments, in particular after the combined treatment. Especially, the leaching of Cr and Cu clearly decreased as a result of accelerated carbonation. The combination of accelerated carbonation with Fe(0) addition reduced the leaching of Cr and Cu even further and reduced also the leaching of Mo, Zn, Pb and Cd compared to untreated BA. Compared with only accelerated carbonation, the Fe(0) addition significantly reduced the leaching of Cr, Cu and Mo

  10. A glacier runoff extension to the Precipitation Runoff Modeling System

    Science.gov (United States)

    Van Beusekom, Ashley E.; Viger, Roland

    2016-01-01

    A module to simulate glacier runoff, PRMSglacier, was added to PRMS (Precipitation Runoff Modeling System), a distributed-parameter, physical-process hydrological simulation code. The extension does not require extensive on-glacier measurements or computational expense but still relies on physical principles over empirical relations as much as is feasible while maintaining model usability. PRMSglacier is validated on two basins in Alaska, Wolverine, and Gulkana Glacier basin, which have been studied since 1966 and have a substantial amount of data with which to test model performance over a long period of time covering a wide range of climatic and hydrologic conditions. When error in field measurements is considered, the Nash-Sutcliffe efficiencies of streamflow are 0.87 and 0.86, the absolute bias fractions of the winter mass balance simulations are 0.10 and 0.08, and the absolute bias fractions of the summer mass balances are 0.01 and 0.03, all computed over 42 years for the Wolverine and Gulkana Glacier basins, respectively. Without taking into account measurement error, the values are still within the range achieved by the more computationally expensive codes tested over shorter time periods.

  11. Runoff estimation in residencial area

    Directory of Open Access Journals (Sweden)

    Meire Regina de Almeida Siqueira

    2013-12-01

    Full Text Available This study aimed to estimate the watershed runoff caused by extreme events that often result in the flooding of urban areas. The runoff of a residential area in the city of Guaratinguetá, São Paulo, Brazil was estimated using the Curve-Number method proposed by USDA-NRCS. The study also investigated current land use and land cover conditions, impermeable areas with pasture and indications of the reforestation of those areas. Maps and satellite images of Residential Riverside I Neighborhood were used to characterize the area. In addition to characterizing land use and land cover, the definition of the soil type infiltration capacity, the maximum local rainfall, and the type and quality of the drainage system were also investigated. The study showed that this neighborhood, developed in 1974, has an area of 792,700 m², a population of 1361 inhabitants, and a sloping area covered with degraded pasture (Guaratinguetá-Piagui Peak located in front of the residential area. The residential area is located in a flat area near the Paraiba do Sul River, and has a poor drainage system with concrete pipes, mostly 0.60 m in diameter, with several openings that capture water and sediments from the adjacent sloping area. The Low Impact Development (LID system appears to be a viable solution for this neighborhood drainage system. It can be concluded that the drainage system of the Guaratinguetá Riverside I Neighborhood has all of the conditions and characteristics that make it suitable for the implementation of a low impact urban drainage system. Reforestation of Guaratinguetá-Piagui Peak can reduce the basin’s runoff by 50% and minimize flooding problems in the Beira Rio neighborhood.

  12. Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions

    Science.gov (United States)

    Abstract for presentation on Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions. The abstract is attached.

  13. Some factors affecting agitation leach test during in-situ leaching of uranium

    International Nuclear Information System (INIS)

    Liao Wensheng; Jiang Yan; Wang Limin; Shi Zhenfeng; Zhao Qiaofu; MARMAR

    2014-01-01

    The agitation leaching test is one of the most fundamental research works in in-situ leaching of uranium. Some factors affecting the test results were analyzed including stirring, leaching time, oxidizer used in alkaline leach, washing solution, the amount and size of ore samples. The results indicate that stirring can enhance diffusion velocity. The leach time l or 2 days is suitable for the samples containing accessible uranium and low acid consumption minerals; whereas 3 or 4 days for those containing refractory ore to leach and slowly acid consuming minerals. For the oxidizer used in alkaline leach, potassium permanganate is better than hydrogen peroxide. Recovery calculated by the leach solution can be directly obtained by its uranium level and the original volume of lixiviant without analyzing and calculating the washing solution. The appropriate amount and size of ore samples for the agitation leaching test are 60 g and <1 mm. By controlling the above factors, the agitation leach test can improve the applicability of the different ore samples and give the more reliable data. (authors)

  14. The Firstflush of Pollutants in Surface Runoff

    OpenAIRE

    Pejman Razi; Amir Taebi

    2005-01-01

    One of the factors impacting quality of water resources is pollution due to urban storm runoff during first stage of storm runoff and is commonly called "firsflush". At this stage the pollution load is rather high. However, if this pollution is properly controlled and managed, the size of the required treatment facilities will be considerably reduced. The surface runoff pollution in the city of Isfahan is high and necessitates the implementation of some control system. For this purpose, ten r...

  15. A mathematical model for soil solute transfer into surface runoff as influenced by rainfall detachment.

    Science.gov (United States)

    Yang, Ting; Wang, Quanjiu; Wu, Laosheng; Zhao, Guangxu; Liu, Yanli; Zhang, Pengyu

    2016-07-01

    Nutrients transport is a main source of water pollution. Several models describing transport of soil nutrients such as potassium, phosphate and nitrate in runoff water have been developed. The objectives of this research were to describe the nutrients transport processes by considering the effect of rainfall detachment, and to evaluate the factors that have greatest influence on nutrients transport into runoff. In this study, an existing mass-conservation equation and rainfall detachment process were combined and augmented to predict runoff of nutrients in surface water in a Loess Plateau soil in Northwestern Yangling, China. The mixing depth is a function of time as a result of rainfall impact, not a constant as described in previous models. The new model was tested using two different sub-models of complete-mixing and incomplete-mixing. The complete-mixing model is more popular to use for its simplicity. It captured the runoff trends of those high adsorption nutrients, and of nutrients transport along steep slopes. While the incomplete-mixing model predicted well for the highest observed concentrations of the test nutrients. Parameters inversely estimated by the models were applied to simulate nutrients transport, results suggested that both models can be adopted to describe nutrients transport in runoff under the impact of rainfall. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Identification of chemical processes influencing constituent mobility during in-situ uranium leaching

    International Nuclear Information System (INIS)

    Sherwood, D.R.; Hostetler, C.J.; Deutsch, W.J.

    1984-07-01

    In-situ leaching of uranium has become a widely accepted method for production of uranium concentrate from ore zones that are too small, too deep, and/or too low in grade to be mined by conventional techniques. One major environmental concern that exists with in-situ leaching of uranium is the possible adverse effects mining might have on regional ground water quality. The leaching solution (lixiviant), which extracts uranium from the ore zone, might also mobilize other potential contaminants (As, Se, Mo, and SO 4 ) associated with uranium ore. Column experiments were performed to investigate the geochemical interactions between a lixiviant and a uranium ore during in-situ leaching and to identify chemical processes that might influence contaminant mobility. The analytical composition data for selected column effluents were used with the MINTEQ code to develop a computerized geochemical model of the system. MINTEQ was used to calculate saturation indices for solid phases based on the composition of the solution. A potential constraint on uranium leaching efficiency appears to be the solubility control of schoepite. Gypsum and powellite solubilities may limit the mobilities of sulfate and molybdenum, respectively. In contrast, the mobilities of arsenic and selenium were not limited by solubility constraints, but were influenced by other chemical interaction between the solution and sediment, perhaps adsorption. Bulk chemical and mineralogical analyses were performed on both the original and leached ores. Using these analyses together with the column effluent data, mass balance calculations were performed on five constituents based on solution chemical analysis and bulk chemical and γ-spectroscopy analysis for the sediment. 6 references, 10 figures, 10 tables

  17. Use of fly ash, phosphogypsum and red mud as a liner material for the disposal of hazardous zinc leach residue waste.

    Science.gov (United States)

    Coruh, Semra; Ergun, Osman Nuri

    2010-01-15

    Increasing amounts of residues and waste materials coming from industrial activities in different processes have become an increasingly urgent problem for the future. The release of large quantities of heavy metals into the environment has resulted in a number of environmental problems. The present study investigated the safe disposal of the zinc leach residue waste using industrial residues such as fly ash, phosphogypsum and red mud. In the study, leachability of heavy metals from the zinc leach residue has been evaluated by mine water leaching procedure (MWLP) and toxicity characteristic leaching procedure (TCLP). Zinc removal from leachate was studied using fly ash, phosphogypsum and red mud. The adsorption capacities and adsorption efficiencies were determined. The adsorption rate data was analyzed according to the pseudo-second-order kinetic, Elovich kinetic and intra-particle diffusion kinetic models. The pseudo-second-order kinetic was the best fit kinetic model for the experimental data. The results show that addition of fly ash, phosphogypsum and red mud to the zinc leach residue drastically reduces the heavy metal content in the leachate and could be used as liner materials.

  18. Pollution characteristics of surface runoff under different restoration types in manganese tailing wasteland.

    Science.gov (United States)

    Wang, Jun; Cheng, Qingyu; Xue, Shengguo; Rajendran, Manikandan; Wu, Chuan; Liao, Jiaxin

    2018-04-01

    A great deal of manganese and associated heavy metals (such as Ni, Cu, Zn, Cd, Pb, etc.) was produced in manganese mining, smelting, and other processes and weathering and leaching of waste slag, which entered rainwater runoff by different means under the action of rainfall runoff. It caused heavy metal pollution in water environment to surrounding areas, and then environmental and human health risks were becoming increasingly serious. In the Xiangtan manganese mine, we studied the characteristics of nutritional pollutants and heavy metals by using the method of bounded runoff plots on the manganese tailing wasteland after carrying out some site treatments using three different approaches, such as (1) exposed tailings, the control treatment (ET), (2) external-soil amelioration and colonization of Cynodon dactylon (Linn.) Pers. turf (EC), and (3) external-soil amelioration and seedling seeding propagation of Cynodon dactylon (Linn.) Pers. (ES). The research showed that the maximum runoff occurred in 20,140,712 rainfall events, and the basic law of runoff was EC area > ET area > ES area in the same rainfall event. The concentration of total suspended solids (TSS) and chemical oxygen demand (COD) of three ecological restoration areas adopted the following rule: ET area > EC area > ES area. Nitrogen (N) existed mainly in the form of water soluble while phosphorus (P) was particulate. The highest concentrations of total nitrogen (TN) and total phosphorus (TP) were 11.57 ± 2.99 mg/L in the EC area and 1.42 ± 0.56 mg/L in the ET area, respectively. Cr, Ni, Pb, Zn, Mn, and Cu in surface runoff from three restoration types all exceeded the class V level of the environmental quality standard for surface water except Cu in EC and ES areas. Pollution levels of heavy metals in surface runoff from three restoration areas are shown as follows: ET area > EC area > ES area. There was a significant positive correlation between TSS and runoff, COD, and TP. And this

  19. ESCA studies on leached glass forms

    International Nuclear Information System (INIS)

    Dawkins, B.G.

    1979-01-01

    Electron Spectroscopy for Chemical Analysis (ESCA) results for frit, obsidian, NBS standard, and Savannah River Laboratory (SRL) glass forms that have been subjected to cumulative water leachings of 36 hours show that [Na] exhibits the largest and fastest change of all the elements observed. Leaching of surface Na occurred within minutes. Surface Na depletion increased with leach time. Continuous x-ray irradiation and argon ion milling induced Na mobility, precluding semiquantitative ESCA analysis at normal operating temperatures. However, the sample stage has been equipped with a liquid nitrogen supply and alkali mobility should be eliminated in future work

  20. ALKALINE CARBONATE LEACHING PROCESS FOR URANIUM EXTRACTION

    Science.gov (United States)

    Thunaes, A.; Brown, E.A.; Rabbitts, A.T.

    1957-11-12

    A process for the leaching of uranium from high carbonate ores is presented. According to the process, the ore is leached at a temperature of about 200 deg C and a pressure of about 200 p.s.i.g. with a solution containing alkali carbonate, alkali permanganate, and bicarbonate ion, the bicarbonate ion functionlng to prevent premature formation of alkali hydroxide and consequent precipitation of a diuranate. After the leaching is complete, the uranium present is recovered by precipitation with NaOH.

  1. Column leaching from biomass combustion ashes

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2015-01-01

    The utilization of biomass combustion ashes for forest soil liming and fertilizing has been addressed in literature. Though, a deep understanding of the ash chemical composition and leaching behavior is necessary to predict potential benefits and environmental risks related to this practice....... In this study, a fly ash sample from an operating Danish power plant based on wood biomass was collected, chemically characterized and investigated for its leaching release of nutrients and heavy metals. A column leaching test was employed. The strongly alkaline pH of all the collected eluates suggested...

  2. Leaching from municipal solid waste incineration residues

    Energy Technology Data Exchange (ETDEWEB)

    Hyks, J.

    2008-02-15

    Leaching of pollutants from Municipal Solid Waste Incineration (MSWI) residues has been investigated combining a range of laboratory leaching experiments with geochemical modeling. Special attention was paid to assessing the applicability of laboratory data for subsequent modeling with respect to presumed full-scale conditions; both sample pretreatment and actual influence of leaching conditions on the results of laboratory experiments were considered. It was shown that sample pretreatment may have large impact on leaching test data. In particular, a significant fraction of Pb was shown mobile during the washing of residues with water. In addition, drying of residues (i.e. slow oxidation) prior to leaching experiments increased the leaching of Cr significantly. Significant differences regarding the leaching behavior of individual elements with respect to (non)equilibrium conditions in column percolation experiments were observed in the study. As a result, three groups of elements were identified based on the predominant leaching control and the influence of (non)equilibrium on the results of the laboratory column experiments: I. Predominantly availability-controlled elements (e.g. Na, K, Cl) II. Solubility-controlled elements (e.g. Ca, S, Si, Al, Ba, and Zn) III. Complexation-controlled elements (e.g. Cu and Ni) With respect to the above groups it was suggested that results of laboratory column experiments can, with consideration, be used to estimate full-scale leaching of elements from Group I and II. However, in order to avoid large underestimations in the assessment of leaching from Group III, it is imperative to describe the time-dependent transport of dissolved organic carbon (DOC) in the tested system or to minimize the physical non-equilibrium during laboratory experiments (e.g. bigger column, slower flow velocity). Forward geochemical modeling was applied to simulate long-term release of elements from a MSWI air-pollution-control residue. Leaching of a

  3. Bacterial leaching of uranium ores - a review

    International Nuclear Information System (INIS)

    Lowson, R.T.

    1975-11-01

    The bacterial leaching of uranium ores involves the bacterially catalysed oxidation of associated pyrite to sulphuric acid and Fe 3+ by autotrophic bacteria and the leaching of the uranium by the resulting acidic, oxidising solution. Industrial application has been limited to Thiobacillus thiooxidans and Thiobacillus ferrooxidans at pH 2 to 3, and examples of these are described. The bacterial catalysis can be improved with nutrients or prevented with poisons. The kinetics of leaching are controlled by the bed depth, particle size, percolation rate, mineralogy and temperature. Current work is aimed at quantitatively defining the parameters controlling the kinetics and extending the method to alkaline conditions with other autotrophic bacteria. (author)

  4. Leaching properties of solidified TRU waste forms

    International Nuclear Information System (INIS)

    Colombo, P.; Neilson, R.M. Jr.

    1979-01-01

    Safety analysis of waste forms requires an estimate of the ability of these forms to retain activity in the disposal environment. This program of leaching tests will determine the leaching properties of TRU contaminated incinerator ash waste forms using hydraulic cement, urea--formaldehyde, bitumen, and vinyl ester--styrene as solidification agents. Three types of leaching tests will be conducted, including both static and flow rate. Five generic groundwaters will be used. Equipment and procedures are described. Experiments have been conducted to determine plate out of 239 Pu, counter efficiency, and stability of counting samples

  5. Leaching and heating process as alternative to produce fish protein powder from Kilka (Clupeonella cultiventris caspia

    Directory of Open Access Journals (Sweden)

    KAVEH RAHMANIFARAH

    2014-05-01

    Full Text Available Rahmanifarah K, Shabanpour B, Shaviklo AR, Aalami M. 2014. Leaching and heating process as alternative to produce fish protein powder from Kilka (Clupeonella cultiventris caspia. Nusantara Bioscience 6: 1-6. The effect of protein extraction procedures (leached mince and heated suspension on selected properties of fish protein powder (proximate composition, pH, color, density, viscosity, fat adsorption, emulsifying capacity, emulsifying stability, foaming capacity, foaming stability, WBC, protein solubility in water, hygroscopicity, Trichloroacetic acid (TCA-soluble peptides and free sulfhydryl groups was investigated. Results showed that Fish protein powder (FPP produced by leaching mince (LM have higher protein, moisture, ash, pH, L*, viscosity, emulsion capacity, emulsion stability, foam capacity, foam stability, water binding capacity (WBC, protein solubility, hygroscopicity, TCA soluble peptides and free sulfhydryl group content than heated suspension (HS (P0.05. Overall, it was observed that high temperature during heating of suspension in HS method makes possible protein denaturation and aggregation. Consequently, based on functional, chemical and physical properties, extraction of fish protein by leaching process was found to be suitable for the production of fish protein powder.

  6. Nitrate leaching, direct and indirect nitrous oxide fluxes from sloping cropland in the purple soil area, southwestern China

    International Nuclear Information System (INIS)

    Zhou Minghua; Zhu Bo; Butterbach-Bahl, Klaus; Wang Tao; Bergmann, Jessica; Brüggemann, Nicolas; Wang Zhenhua; Li Taikui; Kuang Fuhong

    2012-01-01

    This study provides a combined dataset on N loss pathways and fluxes from sloping cropland in the purple soil area, southwestern China. A lysimeter experiment was conducted to quantify nitrate leaching (May 2004–May 2010) and N 2 O emission (May 2009–May 2010) losses. Nitrate leaching was the dominant N loss pathway and annual leaching fluxes ranged from 19.2 to 53.4 kg N ha −1 , with significant differences between individual observation years (P 2 O emissions due to N fertilizer use were 1.72 ± 0.34 kg N ha −1 yr −1 , which corresponds to an emission factor of 0.58 ± 0.12%. However, indirect N 2 O emissions caused by nitrate leaching and surface runoff N losses, may contribute another 0.15–0.42 kg N ha −1 yr −1 . Our study shows that nitrate leaching lowered direct N 2 O emissions, highlighting the importance for a better understanding of the tradeoff between direct and indirect N 2 O emissions for the development of meaningful N 2 O emission strategies. - Highlights: ► High NO 3 − leaching losses lowered direct N 2 O emissions. ► Hydrological N losses induced un-neglected indirect N 2 O emissions. ► Considering both direct and indirect N 2 O emission is needed for reduction strategies. - High nitrate leaching losses from sloping croplands of purple soil are accompanied with reductions in direct N 2 O emissions and stimulations of indirect N 2 O emissions.

  7. Alternative leaching processes for uranium ores

    International Nuclear Information System (INIS)

    Ring, R.J.

    1979-01-01

    Laboratory studies have been carried out to compare the extraction of uranium from Australian ores by conventional leaching in sulphuric acid with that obtained using hydrochloric acid and acidified ferric sulphate solutions. Leaching with hydrochloric acid achieved higher extractions of radium-226 but the extraction of uranium was reduced considerably. The use of acidified ferric sulphate solution reduced acid consumption by 20-40% without any detrimental effect on uranium extraction. The ferric ion, which is reduced during leaching, can be reoxidized and recycled after the addition of acid makeup. Hydrogen peroxide was found to be an effective oxidant in conventional sulphuric acid leaching. It is more expensive than alternative oxidants, but it is non-polluting, lesser quantities are required and acid consumption is reduced

  8. Leaching of potassium in a lysimeter experiment

    International Nuclear Information System (INIS)

    Gerzabek, M.H.

    1996-11-01

    Leaching of potassium was studied in the lysimeter plant in Seibersdorf/Austria (Pannonian climate). Averaged over three years, gravitational water amounted to 15.7% of the sum of precipitation (mean 485 mm) and irrigation (mean 138 mm). Differences between the four soils with respect to drainage were explained by the specific percentage of the soil skeleton. The average yearly potassium leaching ranged from 3.64 kg K/ha·yr (Dystric-Cambisol) to 22.7 kg K/ha·yr (drained Gleysol). Correlation between gravitational water volume and potassium leaching were only significant for one out of four soil types. No correlation was observed between extractable potassium in the soil profiles and potassium leaching. (author)

  9. Reverse osmosis treatment in CO_2 + O_2 to the application of the in-situ leaching of uranium

    International Nuclear Information System (INIS)

    Ruan Zhilong; Li Xilong; Yang Shaowu

    2014-01-01

    Advantages and disadvantages of various groundwater management methods, combined with CO_2 + O_2 characteristics of in situ leaching uranium mining process, use reverse osmosis wastewater treatment technology, has carried on the laboratory test, field condition test and industrial test. Obtained by indoor experiment and field conditions for Cl"- ion concentration variation characteristics; Reverse osmosis treatment effect of wastewater is verified by industrial test, obtained the technical parameters and consumption data, as well as the leaching liquid and adsorption tail liquid pH, SO_4"2"-; Cl"- in the plasma concentration monitoring, and further prove that the reverse osmosis treatment technology is suitable for in-situ leaching of uranium in CO_2 + O_2 in wastewater treatment. (authors)

  10. Using natural Chinese zeolite to remove ammonium from rainfall runoff following urea fertilization of a paddy rice field.

    Science.gov (United States)

    Wang, Xiao-Ling; Qiao, Bin; Li, Song-Min; Li, Jian-Sheng

    2016-03-01

    The potential of natural Chinese zeolite to remove ammonium from rainfall runoff following urea applications to a paddy rice field is assessed in this study. Laboratory batch kinetic and isotherm experiments were carried out first to investigate the ammonium adsorption capacity of the natural zeolite. Field experiments using zeolite adsorption barriers installed at drain outlets in a paddy rice field were also carried out during natural rainfall events to evaluate the barrier's dynamic removal capacity of ammonium. The results demonstrate that the adsorption kinetics are accurately described by the Elovich model, with a coefficient of determination (R (2)) ranging from 0.9705 to 0.9709, whereas the adsorption isotherm results indicate that the Langmuir-Freundlich model provides the best fit (R (2) = 0.992) for the equilibrium data. The field experiments show that both the flow rate and the barrier volume are important controls on ammonium removal from rainfall runoff. A low flow rate leads to a higher ammonium removal efficiency at the beginning of the tests, while a high flow rate leads to a higher quantity of ammonium adsorbed over the entire runoff process.

  11. Silylation of leached-vermiculites following reaction with imidazole and copper sorption behavior

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Saloana S.G.; Pereira, Mariana B.B. [Chemistry Department of Paraíba Federal University, João Pessoa, Paraíba (Brazil); Almeida, Ramon K.S. [Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, 13083-970 Campinas, São Paulo (Brazil); Souza, Antônio G. [Chemistry Department of Paraíba Federal University, João Pessoa, Paraíba (Brazil); Fonseca, Maria G., E-mail: mgardennia@quimica.ufpb.br [Chemistry Department of Paraíba Federal University, João Pessoa, Paraíba (Brazil); Jaber, M. [Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 8220, Laboratoire d' archéologie moléculaire et structurale (LAMS), Boîte courrier 225, 4 place Jussieu, 75005 Paris (France)

    2016-04-05

    Highlights: • Silylated vermiculites reacted covalently with imidazole. • Modified vermiculites adsorbed copper from aqueous solution. • Copper retention in all solids occurred at rapid time of 80 min. • Higher organic content on the solid improved the copper adsorption. - Abstract: Organically modified vermiculites were synthesized by previous silylation of three leached vermiculites, V0.3Cl, V0.5Cl and V0.8Cl, under anhydrous conditions following reaction with imidazole (Im), which acted as chelating agent for copper retention. Elemental analysis, X-ray diffraction, infrared spectroscopy, scanning electronic microscopy, transmission electron microscopy, {sup 29}Si and {sup 13}C NMR and nitrogen adsorption/desorption measurements were used to characterize pristine, leached and organofunctionalized solids. X-ray photoelectron spectroscopy (XPS) was used to evaluate the surface after copper sorption. Parameters such as contact time, pH and initial cation concentration for the adsorption of Cu(II) ions were investigated. The adsorption equilibrium data were fitted using the Langmuir isotherm model and the monolayer adsorption capacities were 2.38, 2.52 and 2.69 mmol g{sup −1} for V0.5Cl-Im, V0.3Cl-Im and V0.8Cl-Im, respectively, at pH 6.0 and 298 K for a time reaction of 80 min. The sorption rates were described by pseudo-second-order kinetics. The chloropropyl imidazole vermiculites are promising adsorbents for the rapid removal of Cu(II) ions from aqueous solution.

  12. Leaching methods for conditioned radioactive waste

    International Nuclear Information System (INIS)

    Carpentiero, R.; Bienvenu, P.; Huebra, A. G. de la; Dale, C.; Grec, D.; Gallego, C.; Rodriguez, M.; Vanderlinden, F.; Voors, P. I.; Welbergen, J.; May, R.; Fays, J.

    2005-01-01

    The physico-chemical characterization of solidified, real or simulated, radioactive waste is essential in determining their long-term stability in conditions close to that which could be encountered during disposal. The evaluation or prediction of the performance of conditioned waste passes through many suitable studies and experiments, according to a documented qualification programme. In this respect the leaching test is among the first important techniques to evaluate the feasibility of a waste form and for comparing and selecting the best waste form. So the leaching behaviour of an immobilized radioactive waste is a relevant property to be studied. The objective of the present report is to collect and describe the most representative leaching methods used in international laboratories, mainly at European level, whether standard or standard-derived. In this instance the work is a summary of the Network knowledge and applications on leaching processes in order to exchange information and scientific and technical experiences in this respect. The focus is to express all the relevant parameters of the test and its field of application. all this background is the needed starting point to clarify the similarities and shortcomings of the methods used in the EN-TRAP laboratories and, subsequently, the possible equalities or differences which can be attributed to the characteristic parameters of the different type of wastes treated. In order to comprise the significance and the effects of the parameters involved in leaching phenomena, an initial discussion on leaching mechanisms and on achievable results is made in this document. The international standardised methods are summarised as being the origin for all the network leaching procedures. This work in a preliminary way represents a comparative review ordered to introduce an unique leaching procedure to be tested in an interlaboratory comparative exercise. Further the unique method would be a quick internal reference

  13. Leaching of irradiated CANDU UO2 fuel

    International Nuclear Information System (INIS)

    Vandergraaf, T.T.; Johnson, L.H.; Lau, D.W.P.

    1980-01-01

    Irradiated fuel, leached at room temperature with distilled water and with slightly chlorinated river water, releases approx. 4% of its cesium inventory over a comparatively sort period of a few days but releases its actinides and rare earths more slowly. The matrix itself dissolves at a rate conservatively calculated to be less than approx. 2 x 10 -6 g UO 2 /cm 2 day and, with time, the leach rates of the various nuclides approach this value

  14. Leaching of nuclear power reactor wastes forms

    International Nuclear Information System (INIS)

    Endo, L.S.; Villalobos, J.P.; Miyamoto, H.

    1986-01-01

    The leaching tests for power reactor wastes carried out at IPEN/CNEN-SP are described. These waste forms consist mainly of spent resins and boric acid concentrates solidified in ordinary Portland cement. All tests were conducted according to the ISO and IAEA recommendations. 3 years leaching results are reported, determining cesium and strontium diffusivity coefficients for boric acid waste form and ion-exchange resins. (Author) [pt

  15. Method for accelerated leaching of solidified waste

    International Nuclear Information System (INIS)

    Fuhrmann, M.; Heiser, J.H.; Pietrzak, R.F.; Franz, E.M.; Colombo, P.

    1990-11-01

    An accelerated leach test method has been developed to determine the maximum leachability of solidified waste. The approach we have taken is to use a semi-dynamic leach test; that is, the leachant is sampled and replaced periodically. Parameters such as temperature, leachant volume, and specimen size are used to obtain releases that are accelerated relative to other standard leach tests and to the leaching of full-scale waste forms. The data obtained with this test can be used to model releases from waste forms, or to extrapolate from laboratory-scale to full-scale waste forms if diffusion is the dominant leaching mechanism. Diffusion can be confirmed as the leaching mechanism by using a computerized mathematical model for diffusion from a finite cylinder. We have written a computer program containing several models including diffusion to accompany this test. The program and a Users' Guide that gives screen-by-screen instructions on the use of the program are available from the authors. 14 refs., 4 figs., 1 tab

  16. Optimization of the factors that accelerate leaching

    International Nuclear Information System (INIS)

    Fuhrmann, M.; Pietrzak, R.F.; Franz, E.M.; Heiser, J.H. III; Colombo, P.

    1989-03-01

    The prediction of long-term leachability of low-level radioactive waste forms is an essential element of disposal-site performance assessment. This report describes experiments and modeling techniques used to develop an accelerated leach test that meets this need. The acceleration in leaching rates caused by the combinations of two or more factors were experimentally determined. These factors were identified earlier as being able to individually accelerate leaching. They are: elevated temperature, the size of the waste form, the ratio of the volume of leachant to the surface area of the waste form, and the frequency of replacement of the leachant. The solidification agents employed were ones that are currently used to treat low-level radioactive wastes, namely portland type I cement, bitumen, and vinyl ester-styrene. The simulated wastes, sodium sulfate, sodium tetraborate, and incinerator ash, are simplified representatives of typical low-level waste streams. Experiments determined the leaching behavior of the radionuclides of cesium (Cs-137), strontium (Sr-85), and cobalt (Co-60 or Co-57) from several different formulations of solidification agents and waste types. Leaching results were based upon radiochemical and elemental analyses of aliquots of the leachate, and on its total alkalinity and pH at various times during the experiment (up to 120 days). Solid phase analyses were carried out by Scanning/Electron Microscopy and Energy Dispersive Spectroscopy on the waste forms before and after some leaching experiments. 43 refs., 96 figs., 16 tabs

  17. Zinc Leaching from Tire Crumb Rubber

    Science.gov (United States)

    Rhodes, E. P.; Ren, J.; Mays, D. C.

    2010-12-01

    Recent estimates indicate that more than 2 billion scrap tires are currently stockpiled in the United States and approximately 280 million more tires are added annually. Various engineering applications utilize recycled tires in the form of shredded tire crumb rubber. However, the use of tire crumb rubber may have negative environmental impacts, especially when the rubber comes into contact with water. A review of the literature indicates that leaching of zinc from tire crumb rubber is the most significant water quality concern associated with using this material. Zinc is generally used in tire manufacturing, representing approximately 1.3% of the final product by mass. This study will report results from the U.S. Environmental Protection Agency’s (EPA’s) Synthetic Precipitation Leaching Procedure, batch leaching tests, and column leaching tests performed to quantify the process by which zinc leaches from tire crumb rubber into water. Results are interpreted with a first-order kinetic attachment/detachment model, implemented with the U.S. Agricultural Research Service software HYDRUS-1D, in order to determine the circumstances when zinc leaching from tire crumb rubber would be expected to comply with the applicable discharge limits. One potential application for recycled tires is replacing sand with tire crumb rubber in granular media filters used for stormwater pollution control. For this to be a viable application, the total zinc in the stormwater discharge must be below the EPA’s benchmark value of 0.117 mg/L.

  18. Rain, Snow, and Spring Runoff Revisited.

    Science.gov (United States)

    Bohren, Craig F.

    1995-01-01

    Explores the theory behind the correlation between warm rain, rapid snowmelt, and the subsequent runoff using the concepts of enthalpy, thermal transfer, and energy transfer. Concludes that rapid runoff is not a consequence of rain per se but of the high humidities associated with the rain. (JRH)

  19. Estimating Subcatchment Runoff Coefficients using Weather Radar and a Downstream Runoff Sensor

    DEFF Research Database (Denmark)

    Ahm, Malte; Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2013-01-01

    This paper presents a method for estimating runoff coefficients of urban drainage subcatchments based on a combination of high resolution weather radar data and flow measurements from a downstream runoff sensor. By utilising the spatial variability of the precipitation it is possible to estimate...... the runoff coefficients of the separate subcatchments. The method is demonstrated through a case study of an urban drainage catchment (678 ha) located in the city of Aarhus, Denmark. The study has proven that it is possible to use corresponding measurements of the relative rainfall distribution over...... the catchment and downstream runoff measurements to identify the runoff coefficients at subcatchment level....

  20. Estimating subcatchment runoff coefficients using weather radar and a downstream runoff sensor.

    Science.gov (United States)

    Ahm, Malte; Thorndahl, Søren; Rasmussen, Michael R; Bassø, Lene

    2013-01-01

    This paper presents a method for estimating runoff coefficients of urban drainage subcatchments based on a combination of high resolution weather radar data and flow measurements from a downstream runoff sensor. By utilising the spatial variability of the precipitation it is possible to estimate the runoff coefficients of the separate subcatchments. The method is demonstrated through a case study of an urban drainage catchment (678 ha) located in the city of Aarhus, Denmark. The study has proven that it is possible to use corresponding measurements of the relative rainfall distribution over the catchment and downstream runoff measurements to identify the runoff coefficients at subcatchment level.

  1. Interfacial adsorption of insulin - Conformational changes and reversibility of adsorption

    NARCIS (Netherlands)

    Mollmann, SH; Jorgensen, L; Bukrinsky, JT; Elofsson, U; Norde, W; Frokjaer, S

    The adsorption of human insulin to Teflon particles was studied with respect to conformational changes and the reversibility of adsorption was examined by total internal reflection fluorescence (TIRF). Adsorption isotherms for the adsorption of human insulin indicated high affinity adsorption, even

  2. ISLSCP II UNH/GRDC Composite Monthly Runoff

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The University of New Hampshire (UNH)/Global Runoff Data Centre (GRDC) composite runoff data combines simulated water balance model runoff estimates...

  3. Influence of organic amendments on diuron leaching through an acidic and a calcareous vineyard soil using undisturbed lysimeters

    International Nuclear Information System (INIS)

    Thevenot, M.; Dousset, S.; Rousseaux, S.; Andreux, F.

    2008-01-01

    The influence of different organic amendments on diuron leaching was studied through undisturbed vineyard soil columns. Two composts (A and D), the second at two stages of maturity, and two soils (VR and Bj) were sampled. After 1 year, the amount of residues (diuron + metabolites) in the leachates of the VR soil (0.19-0.71%) was lower than in the Bj soil (4.27-8.23%), which could be explained by stronger diuron adsorption on VR. An increase in the amount of diuron leached through the amended soil columns, compared to the blank, was observed for the Bj soil only. This result may be explained by the formation of mobile complexes between diuron and water-extractable organic matter (WEOM) through the Bj soil, or by competition between diuron and WEOM for the adsorption sites in the soil. For both soils, the nature of the composts and their degree of maturity did not significantly influence diuron leaching. - The application of organic amendments increased diuron leaching through a sandy-loam soil, in contrast to a clay-loam soil

  4. Influence of organic amendments on diuron leaching through an acidic and a calcareous vineyard soil using undisturbed lysimeters

    Energy Technology Data Exchange (ETDEWEB)

    Thevenot, M. [UMR 1229 Microbiologie et Geochimie des Sols, CMSE, INRA - Universite de Bourgogne, UFR des Sciences de la Terre et de l' Environnement, 6 Boulevard Gabriel, 21000 Dijon (France)], E-mail: mathieu.thevenot@u-bourgogne.fr; Dousset, S. [UMR 5561 Biogeosciences, CNRS - Universite de Bourgogne, UFR des Sciences de la Terre et de l' Environnement, 6 Boulevard Gabriel, 21000 Dijon (France); Rousseaux, S. [EA 4149 Laboratoire de Recherche en Vigne et Vin, Institut Universitaire de la Vigne et du Vin, rue Claude Ladrey, 21000 Dijon (France); Andreux, F. [UMR 1229 Microbiologie et Geochimie des Sols, CMSE, INRA - Universite de Bourgogne, UFR des Sciences de la Terre et de l' Environnement, 6 Boulevard Gabriel, 21000 Dijon (France)

    2008-05-15

    The influence of different organic amendments on diuron leaching was studied through undisturbed vineyard soil columns. Two composts (A and D), the second at two stages of maturity, and two soils (VR and Bj) were sampled. After 1 year, the amount of residues (diuron + metabolites) in the leachates of the VR soil (0.19-0.71%) was lower than in the Bj soil (4.27-8.23%), which could be explained by stronger diuron adsorption on VR. An increase in the amount of diuron leached through the amended soil columns, compared to the blank, was observed for the Bj soil only. This result may be explained by the formation of mobile complexes between diuron and water-extractable organic matter (WEOM) through the Bj soil, or by competition between diuron and WEOM for the adsorption sites in the soil. For both soils, the nature of the composts and their degree of maturity did not significantly influence diuron leaching. - The application of organic amendments increased diuron leaching through a sandy-loam soil, in contrast to a clay-loam soil.

  5. A Review of Thiosulfate Leaching of Gold: Focus on Thiosulfate Consumption and Gold Recovery from Pregnant Solution

    Directory of Open Access Journals (Sweden)

    Bin Xu

    2017-06-01

    Full Text Available Thiosulfate leaching is a promising alternative to cyanidation, and the main hindrances for its wide commercial application are the high thiosulfate consumption and the difficult recovery of dissolved gold. In this review, the four solutions to reduce the consumption of thiosulfate, including the control of reaction conditions, the use of additives, the generation of thiosulfate in situ, and the replacement of traditional cupric-ammonia catalysis, are introduced and evaluated after the presentation of background knowledge about thiosulfate consumption. The replacement of cupric-ammonia catalysis with other metals, such as nickel- and cobalt-based catalysts, is proposed. The reason is that it not only reduces thiosulfate consumption observably via decreasing the redox potential of leach solution significantly but also is beneficial to gold recovery mainly owing to eliminating the interference of cuprous thiosulfate [Cu(S2O33]5−. Based on the comparative analysis for five common recovery techniques of rare-noble metals from pregnant leach solution, ion-exchange resin adsorption is considered to be the most appropriate to recover aurothiosulfate [Au(S2O32]3− because the resin can be employed in the form of resin-in-leach/pulp and, furthermore, is able to be eluted and regenerated simultaneously at ambient temperature. At last, how to reduce the process cost of the resin adsorption technique is discussed. In order to simplify the complex two-stage elution process for loaded resins, the traditional catalysis is suggested to be replaced.

  6. Leaching behavior of simulated high-level waste glass

    International Nuclear Information System (INIS)

    Kamizono, Hiroshi

    1987-03-01

    The author's work in the study on the leaching behavior of simulated high-level waste (HLW) glass were summarized. The subjects described are (1) leach rates at high temperatures, (2) effects of cracks on leach rates, (3) effects of flow rate on leach rates, and (4) an in-situ burial test in natural groundwater. In the following section, the leach rates obtained by various experiments were summarized and discussed. (author)

  7. Long-term elevated temperature leaching of solid waste forms

    International Nuclear Information System (INIS)

    Kenna, B.T.; Murphy, K.D.; Levine, H.S.

    1978-01-01

    Long-term soxhlet leaching of simulated waste glass and ceramic materials was initiated to elucidate leaching behavior of complex wasteforms. A cyclic leaching pattern was found in all systems over a 20 month period. Maxima and minima were observed in the leaching rates of all components studied with the minima coinciding. The data suggested several mechanistic features which are described, but they did not conform with reported simple leaching mechanisms

  8. A Tire-Sulfur Hybrid Adsorption Denitrification (T-SHAD) process for decentralized wastewater treatment.

    Science.gov (United States)

    Krayzelova, Lucie; Lynn, Thomas J; Banihani, Qais; Bartacek, Jan; Jenicek, Pavel; Ergas, Sarina J

    2014-09-15

    Nitrogen discharges from decentralized wastewater treatment (DWT) systems contribute to surface and groundwater contamination. However, the high variability in loading rates, long idle periods and lack of regular maintenance presents a challenge for biological nitrogen removal in DWT. A Tire-Sulfur Hybrid Adsorption Denitrification (T-SHAD) process was developed that combines nitrate (NO3(-)) adsorption to scrap tire chips with sulfur-oxidizing denitrification. This allows the tire chips to adsorb NO3(-) when the influent loading exceeds the denitrification capacity of the biofilm and release it when NO3(-) loading rates are low (e.g. at night). Three waste products, scrap tire chips, elemental sulfur pellets and crushed oyster shells, were used as a medium in adsorption, leaching, microcosm and up-flow packed bed bioreactor studies of NO3(-) removal from synthetic nitrified DWT wastewater. Adsorption isotherms showed that scrap tire chips have an adsorption capacity of 0.66 g NO3(-)-N kg(-1) of scrap tires. Leaching and microcosm studies showed that scrap tires leach bioavailable organic carbon that can support mixotrophic metabolism, resulting in lower effluent SO4(2-) concentrations than sulfur oxidizing denitrification alone. In column studies, the T-SHAD process achieved high NO3(-)-N removal efficiencies under steady state (90%), variable flow (89%) and variable concentration (94%) conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Field-scale evaluation of water fluxes and manure solution leaching in feedlot pen soils.

    Science.gov (United States)

    García, Ana R; Maisonnave, Roberto; Massobrio, Marcelo J; Fabrizio de Iorio, Alicia R

    2012-01-01

    Accumulation of beef cattle manure on feedlot pen surfaces generates large amounts of dissolved solutes that can be mobilized by water fluxes, affecting surface and groundwater quality. Our objective was to examine the long-term impacts of a beef cattle feeding operation on water fluxes and manure leaching in feedlot pens located on sandy loam soils of the subhumid Sandy Pampa region in Argentina. Bulk density, gravimetric moisture content, and chloride concentration were quantified. Rain simulation trials were performed to estimate infiltration and runoff rates. Using chloride ion as a tracer, profile analysis techniques were applied to estimate the soil moisture flux and manure conservative chemical components leaching rates. An organic stratum was found over the surface of the pen soil, separated from the underlying soil by a highly compacted thin layer (the manure-soil interface). The soil beneath the organic layer showed greater bulk density in the A horizon than in the control soil and had greater moisture content. Greater concentrations of chloride were found as a consequence of the partial sealing of the manure-soil interface. Surface runoff was the dominant process in the feedlot pen soil, whereas infiltration was the main process in control soil. Soil moisture flux beneath pens decreased substantially after 15 yr of activity. The estimated minimum leaching rate of chloride was 13 times faster than the estimated soil moisture flux. This difference suggests that chloride ions are not exclusively transported by advective flow under our conditions but also by solute diffusion and preferential flow. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  10. Seasonal herbicide monitoring in soil, runoff and sediments of an olive orchard under conventional tillage

    Science.gov (United States)

    Calderón, Maria Jesus; de Luna, Elena; Gómez, José Alfonso; Cornejo, Juan; Hermosín, M. Carmen

    2015-04-01

    Several pollution episodes in surface and groundwaters with pesticides have occurred in areas where olive crops are established. For that reason, it is necessary to know the evolution of some pesticides in olive trees plantation depending on their seasonal application. This is especially important when conventional tillage is used. A monitoring of two herbicides (terbuthylazine and oxyfluorfen)in the first cm of soil and, in runoff and sediment yield was carried out after several rainfall events. The rainfall occurred during the study was higher in winter than in spring giving rise more runoff in winter. However, no differences in sediment yields were observed between spring and winter. Terbuthylazine depletion from soil is associated to the first important rainfall events in both seasons (41 mm in spring and 30 mm in winter). At the end of the experiment, no terbuthylazine soil residues were recovered in winter whereas 15% of terbuthylazine applied remained in spring. Oxyfluorfen showed a character more persistent than terbuthylazine remaining 48% of the applied at the end of the experiment due to its low water solubility. Higher percentage from the applied of terbuthylazine was recovered in runoff in winter (0.55%) than in spring (0.17%). Nevertheless, no differences in terbuthylazine sediments yields between both seasons were observed. That is in agreement with the values of runoff and sediment yields accumulated in tanks in both seasons. Due to the low water solubility of oxyfluorfen very low amount of this herbicide was recovered in runoff. Whereas, in sediment yields the 39.5% of the total applied was recovered. These data show that the dissipation of terbuthylazine from soil is closely related with leaching processes and in less extent with runoff. However, oxyfluorfen dissipation is more affected by runoff processes since this herbicide is co-transported in sediment yields. Keywords: olive crop, pesticide, runoff, sediments, surface water, groundwater

  11. Pesticide leaching from two Swedish topsoils of contrasting texture amended with biochar

    Science.gov (United States)

    Larsbo, Mats; Löfstrand, Elisabeth; de Veer, David van Alphen; Ulén, Barbro

    2013-04-01

    The use of biochar as a soil amendment has recently increased because of its potential for long-term soil carbon sequestration and its potential for improving soil fertility. The objective of this study was to quantify the effects of biochar soil incorporation on pesticide adsorption and leaching for two Swedish topsoils, one clay soil and one loam soil. We used the non-reactive tracer bromide and the pesticides sulfosulfuron, isoproturon, imidacloprid, propyzamid and pyraclostrobin, substances with different mobility in soil. Adsorption was studied in batch experiments and leaching was studied in experiments using soil columns (20 cm high, 20 cm diameter) where 0.01 kg kg- 1 dw biochar powder originating from wheat residues had been mixed into the top 10 cm. After solute application the columns were exposed to simulated rain three times with a weekly interval and concentrations were measured in the effluent water. The biochar treatment resulted in significantly larger adsorption distribution coefficients (Kd) for the moderately mobile pesticides isoproturon and imidacloprid for the clay soil and for imidacloprid only for the loam soil. Relative leaching of the pesticides ranged from 0.0035% of the applied mass for pyraclostrobin (average Kd = 360 cm3 g- 1) to 5.9% for sulfosulfuron (average Kd = 5.6 cm3 g- 1). There were no significant effects of the biochar amendment on pesticide concentrations in column effluents for the loam soil. For the clay soil concentrations were significantly reduced for isoproturon, imidacloprid and propyzamid while they were significantly increased for the non-mobile fungicide pyraclostrobin suggesting that the transport was facilitated by material originating from the biochar amendment.

  12. Geochemical modeling and assessment of leaching from carbonated municipal solid waste incinerator (MSWI) fly ash.

    Science.gov (United States)

    Wang, Lei; Chen, Qi; Jamro, Imtiaz Ali; Li, Rundong; Li, Yanlong; Li, Shaobai; Luan, Jingde

    2016-06-01

    Municipal solid waste incinerator (MSWI) fly ashes are characterized by high calcium oxide (CaO) content. Carbon dioxide (CO2) adsorption by MSWI fly ash was discussed based on thermogravimetry (TG)/differential thermal analysis (DTA), minerology analysis, and adapting the Stenoir equation. TG/DTA analysis showed that the weight gain of the fly ash below 440 °C was as high as 5.70 %. An adapted Stenoir equation for MSWI fly ash was discussed. The chloride in MSWI fly ash has a major impact on CO2 adsorption by MSWI fly ash or air pollution control (APC) residues. Geochemical modeling of the critical trace elements copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), and antimony (Sb) before and after carbonation was performed using a thermodynamic equilibrium model for solubility and a surface complexation model for metal sorption. Leaching of critical trace elements was generally found to be strongly dependent on the degree of carbonation attained, and their solubility appeared to be controlled by several minerals. Adsorption on ferrum (Fe) and aluminum (Al) colloids was also responsible for removal of the trace elements Cd, Pb, and Sb. We used Hakanson's potential ecological risk index (HPERI) to evaluate the risk of trace element leaching in general. The results demonstrate that the ecological risk showed a V-shaped dependency on pH; the optimum pH of the carbonated fly ash was found to be 10.3-11, resulting from the optimum carbonation (liquid-to-solid (L/S) ratio = 0.25, carbonation duration = ∼30-48 h). The dataset and modeling results presented here provide a contribution to assessing the leaching behavior of MSWI fly ash under a wide range of conditions.

  13. Characterization and source identification of pollutants in runoff from a mixed land use watershed using ordination analyses.

    Science.gov (United States)

    Lee, Dong Hoon; Kim, Jin Hwi; Mendoza, Joseph A; Lee, Chang Hee; Kang, Joo-Hyon

    2016-05-01

    While identification of critical pollutant sources is the key initial step for cost-effective runoff management, it is challenging due to the highly uncertain nature of runoff pollution, especially during a storm event. To identify critical sources and their quantitative contributions to runoff pollution (especially focusing on phosphorous), two ordination methods were used in this study: principal component analysis (PCA) and positive matrix factorization (PMF). For the ordination analyses, we used runoff quality data for 14 storm events, including data for phosphorus, 11 heavy metal species, and eight ionic species measured at the outlets of subcatchments with different land use compositions in a mixed land use watershed. Five factors as sources of runoff pollutants were identified by PCA: agrochemicals, groundwater, native soils, domestic sewage, and urban sources (building materials and automotive activities). PMF identified similar factors to those identified by PCA, with more detailed source mechanisms for groundwater (i.e., nitrate leaching and cation exchange) and urban sources (vehicle components/motor oils/building materials and vehicle exhausts), confirming the sources identified by PCA. PMF was further used to quantify contributions of the identified sources to the water quality. Based on the results, agrochemicals and automotive activities were the two dominant and ubiquitous phosphorus sources (39-61 and 16-47 %, respectively) in the study area, regardless of land use types.

  14. Adsorption. What else?

    OpenAIRE

    Rodrigues, Alirio E.

    2012-01-01

    [EN] Chemical Engineering today combines Molecular and Materials Engineerig and Process and Product Engineering (ChE=M2P2). Cyclic adsorptive processes (Simulated Moving Bed –SMB and Pressure Swing Adsorption-PSA) will be discussed for “old” and “new” applications making use of “old” and “new” (MOFs) adsorbent materials. After revisiting my memory as PhD student and the First Brazilian Adsorption meeting I will review the basic concepts involved in adsorption processes and then...

  15. Molybdenum isotope fractionation during acid leaching of a granitic uranium ore

    Science.gov (United States)

    Migeon, Valérie; Bourdon, Bernard; Pili, Eric; Fitoussi, Caroline

    2018-06-01

    As an attempt to prevent illicit trafficking of nuclear materials, it is critical to identify the origin and transformation of uranium materials from the nuclear fuel cycle based on chemical and isotope tracers. The potential of molybdenum (Mo) isotopes as tracers is considered in this study. We focused on leaching, the first industrial process used to release uranium from ores, which is also known to extract Mo depending on chemical conditions. Batch experiments were performed in the laboratory with pH ranging from 0.3 to 5.5 in sulfuric acid. In order to span a large range in uranium and molybdenum yields, oxidizers such as nitric acid, hydrogen peroxide and manganese dioxide were also added. An enrichment in heavy Mo isotopes is produced in the solution during leaching of a granitic uranium ore, when Mo recovery is not quantitative. At least two Mo reservoirs were identified in the ore: ∼40% as Mo oxides soluble in water or sulfuric acid, and ∼40% of Mo hosted in sulfides soluble in nitric acid or hydrogen peroxide. At pH > 1.8, adsorption and/or precipitation processes induce a decrease in Mo yields with time correlated with large Mo isotope fractionations. Quantitative models were used to evaluate the relative importance of the processes involved in Mo isotope fractionation: dissolution, adsorption, desorption, precipitation, polymerization and depolymerization. Model best fits are obtained when combining the effects of dissolution/precipitation, and adsorption/desorption onto secondary minerals. These processes are inferred to produce an equilibrium isotope fractionation, with an enrichment in heavy Mo isotopes in the liquid phase and in light isotopes in the solid phase. Quantification of Mo isotope fractionation resulting from uranium leaching is thus a promising tool to trace the origin and transformation of nuclear materials. Our observations of Mo leaching are also consistent with observations of natural Mo isotope fractionation taking place during

  16. Herbicide monitoring in soil, runoff waters and sediments in an olive orchard.

    Science.gov (United States)

    Calderon, Maria Jesus; De Luna, Elena; Gomez, Jose Alfonso; Hermosin, M Carmen

    2016-11-01

    Occurrences of surface water contamination by herbicides in areas where olive orchards are established reveal a need to understand soil processes affecting herbicide fate at field scale for this popular Mediterranean crop. A monitoring study with two herbicides (terbuthylazine and oxyfluorfen) in the first 2cm of soil, runoff waters, and sediments, was carried out after under natural rainfall conditions following winter herbicide application. At the end of the 107day field experiment, no residues of the soil applied terbuthylazine were recovered, whereas 42% of the oxyfluorfen applied remained in the top soil. Very low levels of both herbicides were measured in runoff waters; however, concentrations were slightly higher for terbuthylazine (0.53% of applied) than for oxyfluorfen (0.03% of applied), relating to their respective water solubilities. Congruent with soil residue data, 38.15% of the applied oxyfluorfen was found in runoff-sediment, compared to only 0.46% for terbuthylazine. Accordingly, the herbicide soil distribution coefficients measured within runoff field tanks was much greater for oxyfluorfen (Kd=3098) than for terbuthylazine (Kd=1.57). The herbicide oxyfluorfen is co-transported with sediment in runoff, remaining trapped and/or adsorbed to soil particle aggregates, due in part to its low water solubility. In contrast, terbuthylazine soil dissipation may be associated more so with leaching processes, favored by its high water solubility, low sorption, and slow degradation. By comparing these two herbicides, our results reaffirm the importance of herbicide physico-chemical properties in dictating their behavior in soil and also suggest that herbicides with low solubility, as seen in the case oxyfluorfen, remain susceptible to offsite transport associated with sediments. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Mapping ground water vulnerability to pesticide leaching with a process-based metamodel of EuroPEARL.

    Science.gov (United States)

    Tiktak, A; Boesten, J J T I; van der Linden, A M A; Vanclooster, M

    2006-01-01

    To support EU policy, indicators of pesticide leaching at the European level are required. For this reason, a metamodel of the spatially distributed European pesticide leaching model EuroPEARL was developed. EuroPEARL considers transient flow and solute transport and assumes Freundlich adsorption, first-order degradation and passive plant uptake of pesticides. Physical parameters are depth dependent while (bio)-chemical parameters are depth, temperature, and moisture dependent. The metamodel is based on an analytical expression that describes the mass fraction of pesticide leached. The metamodel ignores vertical parameter variations and assumes steady flow. The calibration dataset was generated with EuroPEARL and consisted of approximately 60,000 simulations done for 56 pesticides with different half-lives and partitioning coefficients. The target variable was the 80th percentile of the annual average leaching concentration at 1-m depth from a time series of 20 yr. The metamodel explains over 90% of the variation of the original model with only four independent spatial attributes. These parameters are available in European soil and climate databases, so that the calibrated metamodel could be applied to generate maps of the predicted leaching concentration in the European Union. Maps generated with the metamodel showed a good similarity with the maps obtained with EuroPEARL, which was confirmed by means of quantitative performance indicators.

  18. Analysis of factors affecting the effect of stope leaching

    International Nuclear Information System (INIS)

    Xie Wangnan; Dong Chunming

    2014-01-01

    The industrial test and industrial trial production of stope leaching were carried out at Taoshan orefield of Dabu deposit. The results of test and trial production showed obvious differences in leaching rate and leaching time. Compared with industrial trial production of stope leaching, the leaching rate of industrial test was higher, and leaching time was shorter. It was considered that the blasting method and liquid arrangement were the main factors affecting the leaching rate and leaching time according to analysis. So we put forward the following suggestions: the technique of deep hole slicing tight-face blasting was used to reduce the yield of lump ores, the effective liquid arrangement methods were adopted to make the lixiviant infiltrating throughout whole ore heap, and bacterial leaching was introduced. (authors)

  19. Leaching studies on SYNROC at 950C and 2000C

    International Nuclear Information System (INIS)

    Oversby, V.M.; Ringwood, A.E.

    1982-01-01

    Crushed samples of SYNROC containing 9%, 16% and 20% of simulated high-level nuclear waste were tested for leaching behavior in distilled water at 95 0 C and 200 0 . Leach solutions were analyzed for Cs, Ca, Ba, Sr, Ti, Zr, Nd and U. Results showed that leach rates based on these elements did not change significantly as the waste loading was increased from 9 to 20%. At both temperatures, leach rates showed a decrease as leaching progressed until a plateau level was reached. Plateau leach rates, which were between 10 and 100 times lower than initial leach rates, reflect the expected long term leaching behaviour of the samples. Plateau values of leach rates for SYNROC depend on the element being leached. Highest values are found for Cs and Ba (1 to 2 x 10 -7 g/cm 2 d at 95 0 C) and lowest values for U (5 x 10 -10 g/cm 2 d at 95 0 C). Increasing leaching temperature to 200 0 C produces higher leach rates for all elements except Nd. Comparison of SYNROC leach rate data with that for PNL 76-68 glass shows that at 200 0 C the leach rate for U from SYNROC is 3000 times less than that from glass. (Auth.)

  20. A Simple Adsorption Experiment

    Science.gov (United States)

    Guirado, Gonzalo; Ayllon, Jose A.

    2011-01-01

    The study of adsorption phenomenon is one of the most relevant and traditional physical chemistry experiments performed by chemistry undergraduate students in laboratory courses. In this article, we describe an easy, inexpensive, and straightforward way to experimentally determine adsorption isotherms using pieces of filter paper as the adsorbent…

  1. Influence of liming substances and temperature on microbial activity and leaching of soil organic matter in coniferous forest ecosystems

    International Nuclear Information System (INIS)

    Andersson, Stefan

    1999-01-01

    Liming has been proposed as a means to counteract the anthropogenic acidification of forest soils in Sweden. The increased pH caused by liming may affect the production and leaching of dissolved organic matter (DOM) from the mor humus layer. The aim of this thesis was to assess changes in leaching of dissolved organic carbon (DOC) and nitrogen (DON) and microbial activity in relation to liming. Leaching experiments were carried out in the laboratory with incubated field-limed soils and by monitoring of dissolved components in lysimeter water collected in a field liming experiment in southern Sweden from 1992-1997. Liming increased the leaching of DOC and DON from the mor humus layer but in the B horizon there were indications of different adsorption properties of DON compared to DOC, which affected the leaching of DOC and DON from the B horizon. DOC leaching was mainly regulated by temperature in mor humus from a site in southern Sweden, while pH had a greater effect in mor humus from a site in northern Sweden. This may have been due to relatively higher bacterial growth in the limed mor humus from southern Sweden. The experiments indicated that bacteria had a decisive role in the microbial production of DOM and bacterial activity was stimulated more by the increase in pH than by the change in the chemical composition of DOM after liming. Field data indicated that increasedCO 2 respiration in the limed treatment decreased carbon storage in the mor humus layer. There may have been an increase in carbon and nitrogen storage in the B horizon due to an increased adsorption caused by the higher leaching of DOM from the mor humus layer. The changes in storage could not be confirmed statistically, but there was a significant decline in the C/N ratio in the mor humus layer in the limed treatment. The adsorption patterns of DOC and DON indicated in the field were confirmed in a laboratory experiment

  2. Biocide Runoff from Building Facades: Degradation Kinetics in Soil.

    Science.gov (United States)

    Bollmann, Ulla E; Fernández-Calviño, David; Brandt, Kristian K; Storgaard, Morten S; Sanderson, Hans; Bester, Kai

    2017-04-04

    Biocides are common additives in building materials. In-can and film preservatives in polymer-resin render and paint, as well as wood preservatives are used to protect facade materials from microbial spoilage. Biocides leach from the facade material with driving rain, leading to highly polluted runoff water (up to several mg L -1 biocides) being infiltrated into the soil surrounding houses. In the present study the degradation rates in soil of 11 biocides used for the protection of building materials were determined in laboratory microcosms. The results show that some biocides are degraded rapidly in soil (e.g., isothiazolinones: T 1/2 soils; thus, rainfall events control how often new input to the soil occurs. Time intervals between rainfall events in Northern Europe are shorter than degradation half-lives even for many rapidly degraded biocides. Consequently, residues of some biocides are likely to be continuously present due to repeated input and most biocides can be considered as "pseudo-persistent"-contaminants in this context. This was verified by (sub)urban soil screening, where concentrations of up to 0.1 μg g -1 were detected for parent compounds as well as terbutryn degradation products in soils below biocide treated facades.

  3. Radioactive nuclide adsorption

    International Nuclear Information System (INIS)

    Fukushima, Kimichika.

    1982-01-01

    Purpose: To improve the efficiency of a radioactive nuclide adsorption device by applying a nickel plating on a nickel plate to render the surface active. Constitution: A capturing device for radioactive nuclide such as manganese 54, cobalt 60, 58 and the like is disposed to the inside of a pipeway provided on the upper portion of fuel assemblies through which liquid sodium as the coolant for LMFBR type reactor is passed. The device comprises a cylindrical adsorption body and spacers. The adsorption body is made of nickel and applied with a nickel plating on the surface thereof. The surface of the adsorption body is unevened to result in disturbance in the coolant and thereby improve the adsorptive efficiency. (Kawakami, Y.)

  4. Soil amendments for heavy metals removal from stormwater runoff discharging to environmentally sensitive areas

    Science.gov (United States)

    Trenouth, William R.; Gharabaghi, Bahram

    2015-10-01

    Concentrations of dissolved metals in stormwater runoff from urbanized watersheds are much higher than established guidelines for the protection of aquatic life. Five potential soil amendment materials derived from affordable, abundant sources have been tested as filter media using shaker tests and were found to remove dissolved metals in stormwater runoff. Blast furnace (BF) slag and basic oxygenated furnace (BOF) slag from a steel mill, a drinking water treatment residual (DWTR) from a surface water treatment plant, goethite-rich overburden (IRON) from a coal mine, and woodchips (WC) were tested. The IRON and BOF amendments were shown to remove 46-98% of dissolved metals (Cr, Co, Cu, Pb, Ni, Zn) in repacked soil columns. Freundlich adsorption isotherm constants for six metals across five materials were calculated. Breakthrough curves of dissolved metals and total metal accumulation within the filter media were measured in column tests using synthetic runoff. A reduction in system performance over time occurred due to progressive saturation of the treatment media. Despite this, the top 7 cm of each filter media removed up to 72% of the dissolved metals. A calibrated HYDRUS-1D model was used to simulate long-term metal accumulation in the filter media, and model results suggest that for these metals a BOF filter media thickness as low as 15 cm can be used to improve stormwater quality to meet standards for up to twenty years. The treatment media evaluated in this research can be used to improve urban stormwater runoff discharging to environmentally sensitive areas (ESAs).

  5. Leaching of hazardous substances from a composite construction product – An experimental and modelling approach for fibre-cement sheets

    Energy Technology Data Exchange (ETDEWEB)

    Lupsea, Maria [University of Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France); INRA, UMR 792, F-31400 Toulouse (France); CNRS, UMR 5504, F-31400 Toulouse (France); Paris–Est University, CSTB–Scientific and Technical Centre for the Building Industry, DEE/Environmentand Life Cycle Engineering Team, 24 rue Joseph Fourier, F–38400 Saint Martin d’Hères (France); Tiruta-Barna, Ligia, E-mail: ligia.barna@insa-toulouse.fr [University of Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France); INRA, UMR 792, F-31400 Toulouse (France); CNRS, UMR 5504, F-31400 Toulouse (France); Schiopu, Nicoleta [Paris–Est University, CSTB–Scientific and Technical Centre for the Building Industry, DEE/Environmentand Life Cycle Engineering Team, 24 rue Joseph Fourier, F–38400 Saint Martin d’Hères (France)

    2014-01-15

    Highlights: • Biocide and heavy metals leaching from fibre-cement sheet was investigated. • Equilibrium and dynamic leaching tests were used as modelling support. • The chemical-transport model identifies the main fixation/solubilisation mechanisms. • Biocides as terbutryn and boron were released by the commercial product. • FCS exhibit a cement-like leaching behaviour with high organic carbon release. -- Abstract: The leaching behaviour of a commercial fibre-cement sheet (FCS) product has been investigated. A static pH dependency test and a dynamic surface leaching test have been performed at lab scale. These tests allowed the development of a chemical-transport model capable to predict the release of major and trace elements over the entire pH range, in function of time. FCS exhibits a cement-type leaching behaviour with respect to the mineral species. Potentially hazardous species are released in significant quantities when compared to their total content. These are mainly heavy metals commonly encountered in cement matrixes and boron (probably added as biocide). Organic compounds considered as global dissolved carbon are released in significant concentrations, originating probably from the partial degradation of the organic fibres. The pesticide terbutryn (probably added during the preservative treatment of the organic fibres) was systematically identified in the leachates. The simulation of an upscaled runoff scenario allowed the evaluation of the cumulative release over long periods and the distribution of the released quantities in time, in function of the local exposure conditions. After 10 years of exposure the release reaches significant fractions of the species’ total content – going from 4% for Cu to near 100% for B.

  6. Leaching of gallium from gaiter granite, eastern desert, Egypt

    International Nuclear Information System (INIS)

    Zahran, M.A.; Mahmoud, KH.F.; Mahdy, M.A.; Abd El-Hamid, A.M.

    2006-01-01

    Preliminary leaching tests of gallium from some Egyptian granite rocks such as those of Gabal Gattar area was investigated by using 8 M HCl acid and sodium perchlorate as oxidant. To achieve the optimum leaching conditions, the factors affecting the leaching efficiency as the acid type and concentration, oxidant type and amount, leaching temperature, agitation time, solid / liquid ratio and the effect of grain size were studied. The complete chemical analysis of the collected samples was firstly carried out to determine the chemical features of the Gattarian granite. More than 97% of gallium content was leached when applying these optimum leaching conditions

  7. Green Roofs for Stormwater Runoff Control - Abstract

    Science.gov (United States)

    This project evaluated green roofs as a stormwater management tool. Specifically, runoff quantity and quality from green and flat asphalt roofs were compared. Evapotranspiration from planted green roofs and evaporation from unplanted media roofs were also compared. The influence...

  8. Estimating Runoff Coefficients Using Weather Radars

    DEFF Research Database (Denmark)

    Ahm, Malte; Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2012-01-01

    This paper presents a method for estimating runoff coefficients of urban drainage catchments based on a combination of high resolution weather radar data and insewer flow measurements. By utilising the spatial variability of the precipitation it is possible to estimate the runoff coefficients...... of separate subcatchments. The method is demonstrated through a case study of an urban drainage catchment (678ha) located in the municipality of Aarhus, Denmark. The study has proven it is possible to use corresponding measurements of the relative rainfall distribution over the catchment and runoff...... measurements to identify the runoff coefficients at subcatchment level. The number of potential subcatchments is limited by the number of available rainfall events with a sufficient spatial variability....

  9. Modeling Ballasted Tracks for Runoff Coefficient C

    Science.gov (United States)

    2012-08-01

    In this study, the Regional Transportation District (RTD)s light rail tracks were modeled to determine the Rational Method : runoff coefficient, C, values corresponding to ballasted tracks. To accomplish this, a laboratory study utilizing a : rain...

  10. Leaching Behavior of Heavy Metals from Cement Pastes Using a Modified Toxicity Characteristic Leaching Procedure (TCLP).

    Science.gov (United States)

    Huang, Minrui; Feng, Huajun; Shen, Dongsheng; Li, Na; Chen, Yingqiang; Shentu, Jiali

    2016-03-01

    As the standard toxicity characteristic leaching procedure (TCLP) can not exhaust the acid neutralizing capacity of the cement rotary kiln co-processing solid wastes products which is particularly important for the assessment of the leaching concentrations of heavy metals. A modified TCLP was proposed. The extent of leaching of heavy metals is low using the TCLP and the leaching performance of the different metals can not be differentiated. Using the modified TCLP, however, Zn leaching was negligible during the first 180 h and then sharply increased (2.86 ± 0.18 to 3.54 ± 0.26 mg/L) as the acidity increased (pH leaching is enhanced using the modified TCLP. While Pb leached readily during the first 126 h and then leachate concentrations decreased to below the analytical detection limit. To conclude, this modified TCLP is a more suitable method for these cement rotary kiln co-processing products.

  11. Leaching of artificial radionuclide out of minerals

    International Nuclear Information System (INIS)

    Bogdanov, R.V.; Osipova, I.V.; Sergeev, A.S.

    1992-01-01

    Leaching of radionuclides induced by neutron bombardment in natural silicates and silicophosphate of rare earth elements and calcium, is studied using gamma-spectrometry. It is shown that solution of minerals under the effect of artificial subsoil water at 75 deg C is incongruent character: difference in leaching of cobalt and actinides reaches value equal to two magnitudes. Behaviour of lanthanides as analogs of transplutonium elements is of special interest. Essential role of specimen microphase composition is pointed out. The suggested methodological approach is efficient at selection of matricies for fixaton of radioactive wastes

  12. Leaching of nuclear power reactor waste forms

    International Nuclear Information System (INIS)

    Endo, L.S.; Villalobos, J.P.; Miyamoto, H.

    1987-01-01

    The leaching tests for immobilized power reactor wastes carried out at IPEN are described. These wastes forms consist mainly of spent resins and boric acid concentrates solidified in ordinary Portland cement. All tests were conducted according to the ISO and IAEA recommendations. Three years leaching results are reported. The cesium diffuvity coefficients determined out of these results are about 1 x 10 -8 cm 2 /s for boric acid waste form and 9 x 10 -9 cm 2 /s for ion-exchange resin waste. Strontium diffusivity coefficients found are about 3 x 10 -11 cm 2 /s and 9 x 10 -11 cm 2 /s respectively. (Author) [pt

  13. Urban trees reduce nutrient leaching to groundwater.

    Science.gov (United States)

    Nidzgorski, Daniel A; Hobbie, Sarah E

    2016-07-01

    Many urban waterways suffer from excess nitrogen (N) and phosphorus (P), feeding algal blooms, which cause lower water clarity and oxygen levels, bad odor and taste, and the loss of desirable species. Nutrient movement from land to water is likely to be influenced by urban vegetation, but there are few empirical studies addressing this. In this study, we examined whether or not urban trees can reduce nutrient leaching to groundwater, an important nutrient export pathway that has received less attention than stormwater. We characterized leaching beneath 33 trees of 14 species, and seven open turfgrass areas, across three city parks in Saint Paul, Minnesota, USA. We installed lysimeters at 60 cm depth to collect soil water approximately biweekly from July 2011 through October 2013, except during winter and drought periods, measured dissolved organic carbon (C), N, and P in soil water, and modeled water fluxes using the BROOK90 hydrologic model. We also measured soil nutrient pools (bulk C and N, KCl-extractable inorganic N, Brays-P), tree tissue nutrient concentrations (C, N, and P of green leaves, leaf litter, and roots), and canopy size parameters (leaf biomass, leaf area index) to explore correlations with nutrient leaching. Trees had similar or lower N leaching than turfgrass in 2012 but higher N leaching in 2013; trees reduced P leaching compared with turfgrass in both 2012 and 2013, with lower leaching under deciduous than evergreen trees. Scaling up our measurements to an urban subwatershed of the Mississippi River (~17 400 ha, containing ~1.5 million trees), we estimated that trees reduced P leaching to groundwater by 533 kg in 2012 (0.031 kg/ha or 3.1 kg/km 2 ) and 1201 kg in 2013 (0.069 kg/ha or 6.9 kg/km 2 ). Removing these same amounts of P using stormwater infrastructure would cost $2.2 million and $5.0 million per year (2012 and 2013 removal amounts, respectively). © 2016 by the Ecological Society of America.

  14. Urban Runoff: Getting to the Nonpoint

    OpenAIRE

    Pendall, Rolf

    1994-01-01

    Mandates for water-quality improvement have forced regulators and planners to confront the problem of urban runoff, still an important source of water pollution. This ar­ticle discusses those mandates and how to meet them, and provides examples of ongoing nonpoint water pollution control programs in the San Francisco Bay Area. These examples suggest that cleanup of urban runoff may require more comprehensive regional planning to encourage a de­velopment pattern conducive to pollution control.

  15. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    Energy Technology Data Exchange (ETDEWEB)

    Allegrini, E., E-mail: elia@env.dtu.dk [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark); Butera, S. [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark); Kosson, D.S. [Vanderbilt University, Department of Civil and Environmental Engineering, Box 1831 Station B, Nashville, TN 37235 (United States); Van Zomeren, A. [Energy Research Centre of the Netherlands (ECN), Department of Environmental Risk Assessment, P.O. Box 1, 1755 ZG Petten (Netherlands); Van der Sloot, H.A. [Hans van der Sloot Consultancy, Dorpsstraat 216, 1721 BV Langedijk (Netherlands); Astrup, T.F. [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark)

    2015-04-15

    Highlights: • Relevance of metal leaching in waste management system LCAs was assessed. • Toxic impacts from leaching could not be disregarded. • Uncertainty of toxicity, due to background activities, determines LCA outcomes. • Parameters such as pH and L/S affect LCA results. • Data modelling consistency and coverage within an LCA are crucial. - Abstract: Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results

  16. Study on Shale Adsorption Equation Based on Monolayer Adsorption, Multilayer Adsorption, and Capillary Condensation

    Directory of Open Access Journals (Sweden)

    Qing Chen

    2017-01-01

    Full Text Available Shale gas is an effective gas resource all over the world. The evaluation of pore structure plays a critical role in exploring shale gas efficiently. Nitrogen adsorption experiment is one of the significant approaches to analyze pore size structure of shale. Shale is extremely heterogeneous due to component diversity and structure complexity. Therefore, adsorption isotherms for homogeneous adsorbents and empirical isotherms may not apply to shale. The shape of adsorption-desorption curve indicates that nitrogen adsorption on shale includes monolayer adsorption, multilayer adsorption, and capillary condensation. Usually, Langmuir isotherm is a monolayer adsorption model for ideal interfaces; BET (Brunauer, Emmett, Teller adsorption isotherm is a multilayer adsorption model based on specific assumptions; Freundlich isotherm is an empirical equation widely applied in liquid phase adsorption. In this study, a new nitrogen adsorption isotherm is applied to simultaneously depict monolayer adsorption, multilayer adsorption, and capillary condensation, which provides more real and accurate representation of nitrogen adsorption on shale. In addition, parameters are discussed in relation to heat of adsorption which is relevant to the shape of the adsorption isotherm curve. The curve fitting results indicate that our new nitrogen adsorption isotherm can appropriately describe the whole process of nitrogen adsorption on shale.

  17. ALUMINUM AND CHROMIUM LEACHING WORKSHOP WHITEPAPER

    International Nuclear Information System (INIS)

    McCabe, D; Jeff Pike, J; Bill Wilmarth, B

    2007-01-01

    A workshop was held on January 23-24, 2007 to discuss the status of processes to leach constituents from High Level Waste (HLW) sludges at the Hanford and Savannah River Sites. The objective of the workshop was to examine the needs and requirements for the HLW flowsheet for each site, discuss the status of knowledge of the leaching processes, communicate the research plans, and identify opportunities for synergy to address knowledge gaps. The purpose of leaching of non-radioactive constituents from the sludge waste is to reduce the burden of material that must be vitrified in the HLW melter systems, resulting in reduced HLW glass waste volume, reduced disposal costs, shorter process schedules, and higher facility throughput rates. The leaching process is estimated to reduce the operating life cycle of SRS by seven years and decrease the number of HLW canisters to be disposed in the Repository by 1000 [Gillam et al., 2006]. Comparably at Hanford, the aluminum and chromium leaching processes are estimated to reduce the operating life cycle of the Waste Treatment Plant by 20 years and decrease the number of canisters to the Repository by 15,000-30,000 [Gilbert, 2007]. These leaching processes will save the Department of Energy (DOE) billions of dollars in clean up and disposal costs. The primary constituents targeted for removal by leaching are aluminum and chromium. It is desirable to have some aluminum in glass to improve its durability; however, too much aluminum can increase the sludge viscosity, glass viscosity, and reduce overall process throughput. Chromium leaching is necessary to prevent formation of crystalline compounds in the glass, but is only needed at Hanford because of differences in the sludge waste chemistry at the two sites. Improving glass formulations to increase tolerance of aluminum and chromium is another approach to decrease HLW glass volume. It is likely that an optimum condition can be found by both performing leaching and improving

  18. The effect of different surface materials on runoff quality in permeable pavement systems.

    Science.gov (United States)

    Li, Haiyan; Li, Zhifei; Zhang, Xiaoran; Li, Zhuorong; Liu, Dongqing; Li, Tanghu; Zhang, Ziyang

    2017-09-01

    To investigate the effect of different permeable pavement surface materials on the removal of pollutants from urban storm-runoff, six commonly surface materials (porous asphalt, porous concrete, cement brick, ceramic brick, sand base brick, and shale brick) were selected in this study and the research was carried out by column experiments. Except the concentrations of total suspended solids (TSS), chemical oxygen demand (COD), ammonia nitrogen (NH 4 -N), nitrate nitrogen (NO 3 -N), total nitrogen (TN), and total phosphorus (TP) in the influent and effluent that were measured, the removal mechanism of pollutants was discussed further. The results indicate that the surface materials influence the removal efficiency of pollutants greatly and have different effects on certain pollutant. Furthermore, the physical interception and adsorption would be the main mechanism for the removal of pollutants from runoff. For example, for all surface materials, the average removal efficiency of TSS is nearly about 90.0% because of physical interception. Due to the amount of iron oxide, the removal efficiency of COD, NO 3 -N, and TN of shale brick was 88.2, 35.1, and 17.5%, respectively. NH 4 -N and TN can be easily removed by porous asphalt due to the high content of organic matter. By lacking of useful adsorption sites, all the surface materials had little effect on the removal of TP from runoff. This research could offer useful guidelines for the better design of permeable pavement system and promote the insight into the removal mechanism of pollutants in permeable pavement system. Graphical abstract Different types of materials for the different types of pollutants in the runoff purification capacity were significantly different, overall, shale brick and porous asphalt Shale bricks and porous asphalt have a better purification effect according to the six kinds of materials.

  19. adsorption, eosin, humic, peat

    OpenAIRE

    anshar, andi muhammad

    2015-01-01

    Eosin is one of the dyes commonly used in the industry and has the potential to cause pollution of the water environment. The Eosin pollution treatment methods used in this study was the adsorption method using humin fraction obtained from the peat land comes from Kalimantan. From the research data showed that the adsorption of eosin in humin result of washing with HCl / HF optimum at pH 4 and a contact time of 60 minutes with the adsorption-order rate was 8,4 x 10-3 min-1

  20. Spent LWR fuel leach tests: Waste Isolation Safety Assessment program

    International Nuclear Information System (INIS)

    Katayama, Y.B.

    1979-04-01

    Spent light-water-reactor (LWR) fuels with burnups of 54.5, 28 and 9 MWd/kgU were leach-tested in deionized water at 25 0 C. Fuel burnup has no apparent effect on the calculated leach rates based upon the behavior of 137 Cs and 239+240 Pu. A leach test of 54.5 MWd/kgU spent fuel in synthetic sea brine showed that the cesium-based leach rate is lower in sea brine than in deionized water. A rise in the leach rate was observed after approximately 600 d of cumulative leaching. During the rise, the leach rate for all the measured radionuclides become nearly equal. Evidence suggests that exposure of new surfaces to the leachant may cause the increase. As a result, experimental work to study leaching mechanisms of spent fuel has been initiated. 22 figures

  1. Process for the leaching of AP from propellant

    Science.gov (United States)

    Shaw, G. C.; Mcintosh, M. J. (Inventor)

    1980-01-01

    A method for the recovery of ammonium perchlorate from waste solid rocket propellant is described wherein shredded particles of the propellant are leached with an aqueous leach solution containing a low concentration of surface active agent while stirring the suspension.

  2. Competitive Protein Adsorption - Multilayer Adsorption and Surface Induced Protein Aggregation

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hou, Xiaolin

    2009-01-01

    In this study, competitive adsorption of albumin and IgG (immunoglobulin G) from human serum solutions and protein mixtures onto polymer surfaces is studied by means of radioactive labeling. By using two different radiolabels (125I and 131I), albumin and IgG adsorption to polymer surfaces...... is monitored simultaneously and the influence from the presence of other human serum proteins on albumin and IgG adsorption, as well as their mutual influence during adsorption processes, is investigated. Exploring protein adsorption by combining analysis of competitive adsorption from complex solutions...... of high concentration with investigation of single protein adsorption and interdependent adsorption between two specific proteins enables us to map protein adsorption sequences during competitive protein adsorption. Our study shows that proteins can adsorb in a multilayer fashion onto the polymer surfaces...

  3. Statistical analysis and modelling of surface runoff from arable fields

    OpenAIRE

    P. Fiener; K. Auerswald; F. Winter; M. Disse

    2013-01-01

    Surface runoff generation on arable fields is an important driver of (local) flooding, on-site and off-site damages by erosion, and of nutrient and agrochemical transport. In general, three different processes generate surface runoff (Hortonian runoff, saturation excess runoff, and return of subsurface flow). Despite the developments in our understanding of these processes it remains difficult to predict, which processes govern runoff generation during the course of an event or through...

  4. Heap leaching of clay ish uranium ores

    International Nuclear Information System (INIS)

    Gonzalez, E.; Sedano, A.

    1973-01-01

    This paper describes an experimental facility, built near El Lobo mine. In it we study the beneficiation of low-grade uranium ore. The mineral has a great amount of clay and fines. The flow-sheet used has four steps: head leaching, ph-ajustement, ion-exchange and participation. We show, also, the most interesting results. (Author)

  5. Implementation of the Leaching Environmental Assessment ...

    Science.gov (United States)

    LEAF provides a uniform and integrated approach for evaluating leaching from solid materials (e.g., waste, treated wastes such as by solidification/stabilization, secondary materials such as blast furnace slags, energy residuals such as coal fly ash, soil, sediments, mining and mineral processing wastes). Assessment using LEAF applies a stepwise approach that considers the leaching behavior of COPCs in response to chemical and physical factors that control and material properties across a range of plausible field conditions (US EPA, 2010). The framework provides the flexibility to tailor testing to site conditions and select the extent of testing based on assessment objectives and the level of detailed information needed to support decision-making. The main focus will be to discuss the implementation of LEAF in the US and the How to Guide that has recently been completed. To present the How To Guide for the implementation of the leaching environmental assessment framework to an international audience already familiar with comparable leaching tests in use in Europe. Will be meeting with European colleagues on their interest in expanding methods to include organics.

  6. Metal leaching from refinery waste hydroprocessing catalyst.

    Science.gov (United States)

    Marafi, Meena; Rana, Mohan S

    2018-05-18

    The present study aims to develop an eco-friendly methodology for the recovery of nickel (Ni), molybdenum (Mo), and vanadium (V) from the refinery waste spent hydroprocessing catalyst. The proposed process has two stages: the first stage is to separate alumina, while the second stage involves the separation of metal compounds. The effectiveness of leaching agents, such as NH 4 OH, (NH 4 ) 2 CO 3 , and (NH 4 ) 2 S 2 O 8 , for the extraction of Mo, V, Ni, and Al from the refinery spent catalyst has been reported as a function of reagent concentration (0.5 to 2.0 molar), leaching time (1 to 6 h), and temperature (35 to 60°C). The optimal leaching conditions were achieved to obtain the maximum recovery of Mo, Ni, and V metals. The effect of the mixture of multi-ammonium salts on the metal extraction was also studied, which showed an adverse effect for Ni and V, while marginal improvement was observed for Mo leaching. The ammonium salts can form soluble metal complexes, in which stability or solubility depends on the nature of ammonium salt and the reaction conditions. The extracted metals and support can be reused to synthesize a fresh hydroprocessing catalyst. The process will reduce the refinery waste and recover the expensive metals. Therefore, the process is not only important from an environmental point of view but also vital from an economic perspective.

  7. Leaching of Plastic Additives to Marine Organisms

    NARCIS (Netherlands)

    Koelmans, A.A.; Besseling, E.; Foekema, E.M.

    2014-01-01

    It is often assumed that ingestion of microplastics by aquatic species leads to increased exposure to plastic additives. However, experimental data or model based evidence is lacking. Here we assess the potential of leaching of nonylphenol (NP) and bisphenol A (BPA) in the intestinal tracts of

  8. Gold and Silver Extraction from Leach Solutions

    OpenAIRE

    Bagdaulet K. Kenzhaliyev; Renata R. Iskhakova; Zamzagul D. Dosymbaeva; Esen N. Sulejmenov

    2014-01-01

    There has been carried out an investigation on the extraction of gold and silver from thiosulfate solutions: standard test and technological solutions of chemical and electrochemical leaching. The influence of related metals on the process of extracting gold from solution was studied. There has been conducted a comparative study of the IR spectra of solutions after the sorption of gold, silver and related metals.

  9. Leaching of transuranics observed in lysimeter experiments

    International Nuclear Information System (INIS)

    Erikson, A.; Fredriksson, L.

    1994-01-01

    A lysimeter installation, primarily designed for studies on plant uptake of transuranics from a number of Swedish soils, has been used also for studies on leaching of nuclides with drainage water from contaminated top soil layers in lysimeter vessels through 65 cm subsoil layers. Interception by ion exchanging resins simulated the nuclide transfer to a field drainage system. The study dealt with the contamination of agricultural land. The results obtained in the experiments have to be interpreted cautiously with regard to their bearing on field conditions. Also, the experimental period has been short when compared with the expected ecological half time of transuranic elements in the environment. However, the results indicate that over a first decade the leaching to drainage systems of transuranics in equilibrium with soil environments is of the same order as that of the crop uptake. The ranges assessed for leaching with an excess precipitation of 200 mm from a deposit in the plough layer to the drainage system during a decade are: for plutonium - 0.003-0.8%, for americium - 0.004-0.006% and for neptunium - 0.03-0.06%. The values for plutonium and americium are very similar except for the organic soil used which held the former nuclide very loosely bound. The leaching of neptunium seems to be ten times that for the other nuclides. It is higher on sandy soils than on organic and clay soils. (author)

  10. Duality properties of Gorringe Leach equations

    Science.gov (United States)

    Grandati, Yves; Bérard, Alain; Mohrbach, Hervé

    2009-02-01

    In the category of motions preserving the angular momentum direction, Gorringe and Leach exhibited two classes of differential equations having elliptical orbits. After enlarging slightly these classes, we show that they are related by a duality correspondence of the Arnold Vassiliev type. The specific associated conserved quantities (Laplace Runge Lenz vector and Fradkin Jauch Hill tensor) are then dual reflections of each other.

  11. Sulfide treatment to inhibit mercury adsorption onto activated carbon in carbon-in-pulp gold recovery circuits

    Energy Technology Data Exchange (ETDEWEB)

    Touro, F.J.; Lipps, D.A.

    1988-03-29

    A process for treating a mercury-contaminated, precious metal-containing ore slurry is described comprising: (a) reacting sulfide anions in an aqueous ore slurry of a mercury and precious metal-containing carbonaceous ore, and (b) conducting a simultaneous cyanide leach and carbon-in-pulp adsorption of the precious metal from the carbonaceous ore in the sulfide-containing ore slurry.

  12. Adsorption of As, B, Cr, Mo and Se from coal fly ash leachate by Fe3 modified bentonite clay

    CSIR Research Space (South Africa)

    Vhahangwele, M

    2015-01-01

    Full Text Available Fly ash contains the potentially toxic elements As, B, Cr, Mo and Se which upon contact with water may be leached to contaminate surface and subsurface water bodies. This study aims to evaluate the adsorption of these elements from coal fly ash...

  13. COPPER LEACHING FROM WASTE ELECTRIC CABLES BY BIOHYDROMETALLURGY

    OpenAIRE

    Lambert, Fanny; Bastin, David; Gaydardzhiev, Stoyan; Léonard, Grégoire

    2015-01-01

    This study examines the leaching of copper from waste electric cables by chemical leaching and leaching catalysed by Acidithiobacillus ferrooxidans in terms of leaching kinetics and reagents consumption. Operational parameters such as the nature of the oxidant (Fe3+, O2), the initial ferric iron concentration (0-10 g/L) and the temperature (21-50°C) were identified to have an important influence on the degree of copper solubilisation. At optimal process conditions, copper extraction above 90%...

  14. Enhancements of LEACH Algorithm for Wireless Networks: A Review

    Directory of Open Access Journals (Sweden)

    M. Madheswaran

    2013-12-01

    Full Text Available Low Energy Adaptive Clustering Hierarchy (LEACH protocol is the first hierarchical cluster based routing protocol successfully used in the Wireless Sensor Networks (WSN. In this paper, various enhancements used in the original LEACH protocol are examined. The basic operations, advantages and limitations of the modified LEACH algorithms are compared to identify the research issues to be solved and to give the suggestions for the future proposed routing algorithms of wireless networks based on LEACH routing algorithm.

  15. Acid agglomeration heap leaching: present status, principle and applications

    International Nuclear Information System (INIS)

    Zeng Yijun

    2004-01-01

    For extracting valuable metal from clay-bearing acidic ores of poor permeability, agglomerated acid heap leaching appears to be the most effective method, whereas conventional leaching and general heap leaching bring about unsatisfactory recovery and poor economic returns. The present state of research work on acid agglomeration worldwide and its basic principle are discussed. The first commercial application employing acid agglomeration-heap leaching in China is also introduced

  16. Long-term lessons on pesticide leaching obtained via the Danish Pesticide Leaching Assessment Programme

    DEFF Research Database (Denmark)

    Rosenbom, Anette E.; Olsen, Preben; Plauborg, Finn

    To avoid any unacceptable influence on the environment posed by pesticides and their degradation products, all pesticides used in the European Union needs authorization. The authorization procedure includes assessing the leaching risk of both pesticides and their degradation products...

  17. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T [Huntington Beach, CA; Sahimi, Muhammad [Altadena, CA; Fayyaz-Najafi, Babak [Richmond, CA; Harale, Aadesh [Los Angeles, CA; Park, Byoung-Gi [Yeosu, KR; Liu, Paul K. T. [Lafayette Hill, PA

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  18. Co adsorption in kaolinite

    International Nuclear Information System (INIS)

    Souza, Eliel S.; Silva, Paulo S.C.

    2017-01-01

    Adsorption of metal ions in clay minerals has been used as an alternative to water and effluents treatment. Kaolinite is a clay mineral that presents low specific surface area and exchange ion capacity. Nevertheless, structural modifications can be achieved by means of acid or thermal activation. In this paper, it was studied the surface area of kaolinite/bentonite, kaolinite/activated carbon mixtures, thermal activated kaolinite and thermal activated kaolinite/activated carbon mixture. The mixture of kaolinite/activated carbon was tested for pH, contact time, interfering ions and initial concentration effects in the cobalt adsorption. Results showed that the optimized parameters are pH 6 and contact time of 30 min. Chromium acted as a competitive ion, zinc does not appear to have affected adsorption while iron seems to have favored it. Langmuir and Freundlich isotherms indicated that the adsorption of Co in the mixture of kaolinite/activated carbon is a spontaneous process. (author)

  19. Co adsorption in kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Eliel S.; Silva, Paulo S.C., E-mail: eliel201019@hotmail.com, E-mail: pscsilva@ipen.br [Instituto de Pesquisas Energética s e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    Adsorption of metal ions in clay minerals has been used as an alternative to water and effluents treatment. Kaolinite is a clay mineral that presents low specific surface area and exchange ion capacity. Nevertheless, structural modifications can be achieved by means of acid or thermal activation. In this paper, it was studied the surface area of kaolinite/bentonite, kaolinite/activated carbon mixtures, thermal activated kaolinite and thermal activated kaolinite/activated carbon mixture. The mixture of kaolinite/activated carbon was tested for pH, contact time, interfering ions and initial concentration effects in the cobalt adsorption. Results showed that the optimized parameters are pH 6 and contact time of 30 min. Chromium acted as a competitive ion, zinc does not appear to have affected adsorption while iron seems to have favored it. Langmuir and Freundlich isotherms indicated that the adsorption of Co in the mixture of kaolinite/activated carbon is a spontaneous process. (author)

  20. Pesticide leaching through sandy and loamy fields - long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme.

    Science.gov (United States)

    Rosenbom, Annette E; Olsen, Preben; Plauborg, Finn; Grant, Ruth; Juhler, René K; Brüsch, Walter; Kjær, Jeanne

    2015-06-01

    The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Laboratory study on leaching of a sandstone-type uranium deposit for acid in-situ leaching

    International Nuclear Information System (INIS)

    Wen Zhenqian; Yao Yixuan; Zheng Jianping; Jiang Yan; Cui Xin; Xing Yongguo; Hao Jinting; Tang Huazhang

    2013-01-01

    Ore samples were took from in-situ leaching experiment boreholes in a sandstone-type uranium deposit. Technological mineralogy study, agitating leaching and column leaching experiments were carried. The results show that the content of minerals consuming acid and deoxidized minerals is low. When sulfuric acid concentration was 1O g/L, initial uranium content was 0.0224%, and liquid-to-solid ratio was l.91, leaching rate of column leaching experiments is 89.19%, acid consumption is 8.2 kg/t ore, acid consumption is 41.88 t/tU. Acid leaching, technology is recommend for field in-situ leaching experiment, sulfuric acid concentration in confecting solution is 10 g/L, and oxidizing agent is needless during leaching process. (authors)

  2. Study on Water Quality of Surface Runoff and Groundwater Runoff on the Basis of Separation by a Numerical Filter

    OpenAIRE

    Kawara, Osami; Fukumoto, Kohji

    1994-01-01

    In this study we investigated the water quality of surface runoff and groundwater runoff from the basins of the Yodo River and the Asahi River based on that separated by a numerical filter. The water quality of the surface runoff is greatly different from the groundwater runoff. The tendency of concentration change in accordance with river discharges is different from each other. The water qtiality of groundwater runoff changes with river discharges clockwise in many cases. The differences of...

  3. Leaching of Titanium and Silicon from Low-Grade Titanium Slag Using Hydrochloric Acid Leaching

    Science.gov (United States)

    Zhao, Longsheng; Wang, Lina; Qi, Tao; Chen, Desheng; Zhao, Hongxin; Liu, Yahui; Wang, Weijing

    2018-05-01

    Acid-leaching behaviors of the titanium slag obtained by selective reduction of vanadium-bearing titanomagnetite concentrates were investigated. It was found that the optimal leaching of titanium and silicon were 0.7% and 1.5%, respectively. The titanium and silicon in the titanium slag were firstly dissolved in the acidic solution to form TiO2+ and silica sol, and then rapidly reprecipitated, forming hydrochloric acid (HCl) leach residue. Most of the silicon presented in the HCl leach residue as floccules-like silica gel, while most of the titanium was distributed in the nano-sized rod-like clusters with crystallite refinement and intracrystalline defects, and, as such, 94.3% of the silicon was leached from the HCl leach residue by alkaline desilication, and 96.5% of the titanium in the titanium-rich material with some rutile structure was then digested by the concentrated sulfuric acid. This provides an alternative route for the comprehensive utilization of titanium and silicon in titanium slag.

  4. Structure sensitivity in adsorption

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Nielsen, Ole Holm; Nørskov, Jens Kehlet

    1997-01-01

    The structure sensitivity of CO adsorption on different flat, stepped, kinked and reconstructed Pt surfaces is studied using large-scale density-functional calculations. We find an extremely strong structure sensitivity in the adsorption energy with variations up to 1 eV (or 100%) from one...... structure to the next. We propose a model to explain this behavior, and use it to discuss more generally the origin of structure sensitivity in heterogeneous catalysis....

  5. Trace Metals in Urban Stormwater Runoff and their Management

    Science.gov (United States)

    Li, T.; Hall, K.; Li, L. Y.; Schreier, H.

    2009-04-01

    In past decades, due to the rapid urbanization, land development has replaced forests, fields and meadows with impervious surfaces such as roofs, parking lots and roads, significantly affecting watershed quality and having an impact on aquatic systems. In this study, non-point source pollution from a diesel bus loop was assessed for the extent of trace metal contamination of Cu, Mn, Fe, and Zn in the storm water runoff. The study was carried out at the University of British Columbia (UBC) in the Greater Vancouver Regional District (GVRD) of British Columbia, Canada. Fifteen storm events were monitored at 3 sites from the diesel bus loop to determine spatial and temporal variations of dissolved and total metal concentrations in the storm water runoff. The dissolved metal concentrations were compared with the provincial government discharge criteria and the bus loop storm water quality was also compared with previous studies conducted across the GVRD urban area. To prevent storm water with hazardous levels of contaminants from being discharged into the urban drainage system, a storm water catch basin filter was installed and evaluated for its efficiency of contaminants removal. The perlite filter media adsorption capacities for the trace metals, oil and grease were studied for better maintenance of the catch basin filter. Dissolved copper exceeded the discharge criteria limit in 2 out of 15 cases, whereas dissolved zinc exceeded the criteria in 4 out of 15 cases, and dissolved manganese was below the criteria in all of the events sampled. Dissolved Cu and Zn accounted for 36 and 45% of the total concentration, whereas Mn and Fe only accounted for 20 and 4% of their total concentration, respectively. Since they are more mobile and have higher bioaccumulation potentials, Zn and Cu are considered to be more hazardous to the aquatic environment than Fe and Mn. With high imperviousness (100%) and intensive traffic at the UBC diesel bus loop, trace metal concentrations

  6. Field application of farmstead runoff to vegetated filter strips: surface and subsurface water quality assessment.

    Science.gov (United States)

    Larson, Rebecca A; Safferman, Steven I

    2012-01-01

    Farmstead runoff poses significant environmental impacts to ground and surface waters. Three vegetated filter strips were assessed for the treatment of dairy farmstead runoff at the soil surface and subsurface at 0.3- or 0. 46-m and 0. 76-m depths for numerous storm events. A medium-sized Michigan dairy was retrofitted with two filter strips on sandy loam soil and a third filter strip was implemented on a small Michigan dairy with sandy soil to collect and treat runoff from feed storage, manure storage, and other impervious farmstead areas. All filter strips were able to eliminate surface runoff via infiltration for all storm events over the duration of the study, eliminating pollutant contributions to surface water. Subsurface effluent was monitored to determine the contributing groundwater concentrations of numerous pollutants including chemical oxygen demand (COD), metals, and nitrates. Subsurface samples have an average reduction of COD concentrations of 20, 11, and 85% for the medium dairy Filter Strip 1 (FS1), medium dairy Filter Strip 2 (FS2), and the small Michigan dairy respectively, resulting in average subsurface concentrations of 355, 3960, and 718 mg L COD. Similar reductions were noted for ammonia and total Kjeldahl nitrogen (TKN) in the subsurface effluent. The small Michigan dairy was able to reduce the pollutant leachate concentrations of COD, TKN, and ammonia over a range of influent concentrations. Increased influent concentrations in the medium Michigan dairy filter strips resulted in an increase in COD, TKN, and ammonia concentrations in the leachate. Manganese was leached from the native soils at all filter strips as evidenced by the increase in manganese concentrations in the leachate. Nitrate concentrations were above standard drinking water limits (10 mg L), averaging subsurface concentrations of 11, 45, and 25 mg L NO-N for FS1, FS2, and the small Michigan dairy, respectively. Copyright © by the American Society of Agronomy, Crop Science

  7. Leaching of boron, arsenic and selenium from sedimentary rocks: II. pH dependence, speciation and mechanisms of release

    Energy Technology Data Exchange (ETDEWEB)

    Tabelin, Carlito Baltazar, E-mail: carlito@trans-er.eng.hokudai.ac.jp [Laboratory of Soil Environment Engineering, Faculty of Engineering, Hokkaido University, Sapporo (Japan); Hashimoto, Ayaka, E-mail: a.hashimoto@diaconsult.co.jp [DIA Consultants Co. Ltd., Sapporo (Japan); Igarashi, Toshifumi, E-mail: tosifumi@eng.hokudai.ac.jp [Laboratory of Groundwater and Mass Transport, Faculty of Engineering, Hokkaido University, Sapporo (Japan); Yoneda, Tetsuro, E-mail: yonet@eng.hokudai.ac.jp [Laboratory of Soil Environment Engineering, Faculty of Engineering, Hokkaido University, Sapporo (Japan)

    2014-03-01

    Sedimentary rocks excavated in Japan from road- and railway-tunnel projects contain relatively low concentrations of hazardous trace elements like boron (B), arsenic (As) and selenium (Se). However, these seemingly harmless waste rocks often produced leachates with concentrations of hazardous trace elements that exceeded the environmental standards. In this study, the leaching behaviors and release mechanisms of B, As and Se were evaluated using batch leaching experiments, sequential extraction and geochemical modeling calculations. The results showed that B was mostly partitioned with the residual/crystalline phase that is relatively stable under normal environmental conditions. In contrast, the majority of As and Se were associated with the exchangeable and organics/sulfides phases that are unstable under oxidizing conditions. Dissolution of water-soluble phases controlled the leaching of B, As and Se from these rocks in the short term, but pyrite oxidation, calcite dissolution and adsorption/desorption reactions became more important in the long term. The mobilities of these trace elements were also strongly influenced by the pH of the rock-water system. Although the leaching of Se only increased in the acidic region, those of B and As were enhanced under both acidic and alkaline conditions. Under strongly acidic conditions, the primarily release mechanism of B, As and Se was the dissolution of mineral phases that incorporated and/or adsorbed these elements. Lower concentrations of these trace elements in the circumneutral pH range could be attributed to their strong adsorption onto minerals like Al-/Fe-oxyhydroxides and clays, which are inherently present and/or precipitated in the rock-water system. The leaching of As and B increased under strongly alkaline conditions because of enhanced desorption and pyrite oxidation while that of Se remained minimal due to its adsorption onto Fe-oxyhydroxides and co-precipitation with calcite. - Highlights: • The bulk of

  8. Total pollution effect of urban surface runoff.

    Science.gov (United States)

    Luo, Hongbing; Luo, Lin; Huang, Gu; Liu, Ping; Li, Jingxian; Hu, Sheng; Wang, Fuxiang; Xu, Rui; Huang, Xiaoxue

    2009-01-01

    For pollution research with regard to urban surface runoff, most sampling strategies to date have focused on differences in land usage. With single land-use sampling, total surface runoff pollution effect cannot be evaluated unless every land usage spot is monitored. Through a new sampling strategy known as mixed stormwater sampling for a street community at discharge outlet adjacent to river, this study assessed the total urban surface runoff pollution effect caused by a variety of land uses and the pollutants washed off from the rain pipe system in the Futian River watershed in Shenzhen City of China. The water quality monitoring indices were COD (chemical oxygen demand), TSS (total suspend solid), TP (total phosphorus), TN (total nitrogen) and BOD (biochemical oxygen demand). The sums of total pollution loads discharged into the river for the four indices of COD, TSS, TN, and TP over all seven rainfall events were very different. The mathematical model for simulating total pollution loads was established from discharge outlet mixed stormwater sampling of total pollution loads on the basis of four parameters: rainfall intensity, total land area, impervious land area, and pervious land area. In order to treat surface runoff pollution, the values of MFF30 (mass first flush ratio) and FF30 (first 30% of runoff volume) can be considered as split-flow control criteria to obtain more effective and economical design of structural BMPs (best management practices) facilities.

  9. A review on adsorption refrigeration technology and adsorption deterioration in physical adsorption systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D.C.; Li, Y.H. [College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Li, D.; Zhang, J.P. [College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Xia, Y.Z. [Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China)

    2010-01-15

    As one kind of environmentally friendly refrigeration, the adsorption refrigeration has attracted many attentions in resent decades. This paper introduces the researches of adsorption refrigeration systems with the commonly used working pairs, advanced adsorption cycles, heat and mass transfer enhancement and attempts of adsorption refrigeration applications. Poor heat and mass transfer problem is a bottleneck to prevent the improvements of the adsorption refrigeration technique. Two ways to enhance the heat and mass transfer are discussed in this paper. The adsorption deterioration of adsorbent, another obstacle to physical adsorption refrigeration applications, is also pointed out. And the possible reasons and the possible methods are analyzed. (author)

  10. Study and application of new chelating resin to recovery uranium from in-situ leach solution with high content saline chloride ion

    International Nuclear Information System (INIS)

    Zhang Jianguo; Qiu Yueshuang; Feng Yu; Deng Huidong; Zhao Chaoya

    2014-01-01

    Research on the adsorption and elution property of D814 chelating resin was carried out aiming at the difficult separation of uranium from high content saline chloride ion in situ leach liquor and the adsorption mechanism is also discussed. Influence factors such as contact time, pH value, Ca"2"+, Mg"2"+ and Cl"- concentration etc. to the resin adsorption were studied. Experimental results show that adsorption rate is lowly which need 6h to arrive at the adsorption equilibrium. The resin adsorption uranium pH in the solution is from l.33 to 9. When total salinity is over 20 g/L, calcium ion, and magnesium ion is about 3 g/L, there are no big influence on resin adsorption capacity. The resin has good chloride ion resistance. When chloride ion is over 60 g/L, it is no influence on resin adsorption uranium. Column experiment results indicate that ratio of saturation volume to break-through point volume is l.82, resin saturation uranium capacity is 40.5 mg. U/_g_(_∓_)_R. When elution volume bed number is 23, the eluted solution uranium concentration is below 80 mg/L. The elution rate of the uranium is 96.2%. (authors)

  11. Irreversible adsorption of phenolic compounds by activated carbons

    International Nuclear Information System (INIS)

    Grant, T.M.; King, C.J.

    1988-12-01

    Studies were undertaken to determine the reasons why phenolic sorbates can be difficult to remove and recover from activated carbons. The chemical properties of the sorbate and the adsorbent surface, and the influences of changes in the adsorption and desorption conditions were investigated. Comparison of isotherms established after different contact times or at different temperatures indicated that phenolic compounds react on carbon surfaces. The reaction rate is a strong function of temperature. Regeneration of carbons by leaching with acetone recovered at least as much phenol as did regeneration with other solvents or with displacers. The physiochemical properties of adsorbents influences irreversible uptakes. Sorbates differed markedly in their tendencies to undergo irreversible adsorption. 64 refs., 47 figs., 32 tabs

  12. Irreversible adsorption of phenolic compounds by activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Grant, T.M.; King, C.J.

    1988-12-01

    Studies were undertaken to determine the reasons why phenolic sorbates can be difficult to remove and recover from activated carbons. The chemical properties of the sorbate and the adsorbent surface, and the influences of changes in the adsorption and desorption conditions were investigated. Comparison of isotherms established after different contact times or at different temperatures indicated that phenolic compounds react on carbon surfaces. The reaction rate is a strong function of temperature. Regeneration of carbons by leaching with acetone recovered at least as much phenol as did regeneration with other solvents or with displacers. The physiochemical properties of adsorbents influences irreversible uptakes. Sorbates differed markedly in their tendencies to undergo irreversible adsorption. 64 refs., 47 figs., 32 tabs.

  13. Life cycle assessment and residue leaching: the importance of parameter, scenario and leaching data selection.

    Science.gov (United States)

    Allegrini, E; Butera, S; Kosson, D S; Van Zomeren, A; Van der Sloot, H A; Astrup, T F

    2015-04-01

    Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results of the study, recommendations are provided regarding the use of leaching data in LCA studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Leaching behaviour of strontium-90 in cement composites

    International Nuclear Information System (INIS)

    Matsuzuru, H.; Ito, A.

    1977-01-01

    The leaching of 90 Sr from a cement composite into an aqueous phase has been studied by the method recommended by IAEA. The amount leached was measured as functions of waste to cement ratio (Wa/C), salt content of waste, temperature of leachant and curing time of specimens. The leach coefficient of 90 Sr varies from ca. 6 x 10 -8 to 4 x 10 -7 cm 2 /day depending on the composition of specimen and the leaching conditions. The leachability depends on such factors as Wa/C, temperature of leachant and curing time. The Portland cement composite gives a higher leaching fraction than the slag cement one. Additives used have no significant effect on the leachability. The amount leached in deionized water as a leachant is higher than in synthetic sea water. On the basis of the results obtained, the amount of 90 Sr leached from a composite of 200 1 drum size for an extended period was estimated. (author)

  15. Pilot test of bacterial percolation leaching at Fuzhou uranium mine

    International Nuclear Information System (INIS)

    Fan Baotuan; Liu Jian; Jiang Yngqiong; Cai Chunhui; Jiang Lang; Zhou Renhua; Tong Changning; Zhang Hongli

    2006-01-01

    Total 18 t uranium ores of Fuzhou Uranium Mine packed in three or four columns in series were leached by bacterial percolation. The results show that without adding any other chemical oxidant such as sodium chlorate, the leaching rate measured by residue is 91.45%-94.48%, leaching time is 50-60 d, acid consumption is 6.17%-7.75%, and residue grade is 0.0149%-0.0208%. Compared with conventional percolation leaching process, the leaching rate is improved by 3%, leaching time is shorted by 26%, and acid consumption is saved by 34%. Accumulation pattern of ΣFe and F - in the process of leaching is discussed. Influence of F - on bacterial growth, regeneration of barren solution as well as correlative techniques are reviewed. (authors)

  16. Adsorption of uranium on halloysite

    International Nuclear Information System (INIS)

    Kilislioglu, A.; Bilgin, B.

    2002-01-01

    Adsorption of uranium (U(VI)) from aqueous solutions on halloysite type clay was studied as a function of amount of adsorbent, initial concentration and pH. The values of adsorption data were fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption was calculated as 5.91 kJ/mol from D-R adsorption isotherm. Lagergren and Bangham equation has been used for dynamic modelling of process and the rate constants of adsorption of uranium on halloysite type clay were calculated at 293, 313 and 333 K. In order to explain the mechanism of adsorption reaction, the rate constants were calculated at high and low uranium concentrations. Adsorption reaction was studied at 293, 303, 313, 323 and 333 K for halloysite type clay and also thermodynamic constants have been calculated. The results show that the adsorption reaction was endothermic and more spontaneous at high temperature. (orig.)

  17. Adsorption of uranium on halloysite

    Energy Technology Data Exchange (ETDEWEB)

    Kilislioglu, A.; Bilgin, B. [Istanbul Univ. (Turkey). Faculty of Engineering

    2002-07-01

    Adsorption of uranium (U(VI)) from aqueous solutions on halloysite type clay was studied as a function of amount of adsorbent, initial concentration and pH. The values of adsorption data were fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption was calculated as 5.91 kJ/mol from D-R adsorption isotherm. Lagergren and Bangham equation has been used for dynamic modelling of process and the rate constants of adsorption of uranium on halloysite type clay were calculated at 293, 313 and 333 K. In order to explain the mechanism of adsorption reaction, the rate constants were calculated at high and low uranium concentrations. Adsorption reaction was studied at 293, 303, 313, 323 and 333 K for halloysite type clay and also thermodynamic constants have been calculated. The results show that the adsorption reaction was endothermic and more spontaneous at high temperature. (orig.)

  18. Urban runoff forecasting with ensemble weather predictions

    DEFF Research Database (Denmark)

    Pedersen, Jonas Wied; Courdent, Vianney Augustin Thomas; Vezzaro, Luca

    This research shows how ensemble weather forecasts can be used to generate urban runoff forecasts up to 53 hours into the future. The results highlight systematic differences between ensemble members that needs to be accounted for when these forecasts are used in practice.......This research shows how ensemble weather forecasts can be used to generate urban runoff forecasts up to 53 hours into the future. The results highlight systematic differences between ensemble members that needs to be accounted for when these forecasts are used in practice....

  19. Microbial leaching of low grade copper ores

    International Nuclear Information System (INIS)

    Rauf, A.; Ashfaq, M.

    1991-01-01

    Biotechnology is regarded as one of the most promising and revolutionary solution to various problems which are generally faced in the extraction of metals from their ores such as high energy, capital costs and environmental pollution. The paper deals with the study of low grade copper ores for their beneficiation and extraction of copper. The ores used were chalcopyrite and oxidized copper ores. Microorganisms play a vital role in the solubilization of valuable contents from ores such as copper and other metals. Studies have been conducted on the indigenous copper ores by using thiobacillus ferro oxidans and thiobacillus thio oxidans. For comparison purpose some experiments have also been conducted by chemical leaching. The results of bacterial leaching are encouraging. (author)

  20. Leaching of Electronic Waste Using Biometabolised Acids

    Institute of Scientific and Technical Information of China (English)

    M. Saidan; B. Brown; M. Valix

    2012-01-01

    The revolution in information and communication technology has brought huge technical benefits and wealth, but has created a major global problem: the generation of vast amounts of electronic waste, or e-waste through product obsolesce. The challenge in managing e-waste will be in developing sustainable recycling tech- nologies that are able to address the volume and complexity of this waste using cost effective and ecologically sen-sitive methods. In this study, the capability or microorganism metabolic acids in dissolving the metallic tractions from waste printed circuit boards was examined. Several factors were considered in the examination of the activityof the acids-including secondary reactions, solution pH, temperature and the nature of ligands in solutions (or bioacid constituents). The leaching tests were cgnducted ex-situ, using synthetic organic acids. Leaching was performed for periods of up to 6 hat 70-90 ℃ and 1000 r-min-1.

  1. Determining leach rates of monolithic waste forms

    International Nuclear Information System (INIS)

    Gilliam, T.M.; Dole, L.R.

    1986-01-01

    The ANS 16.1 Leach Procedure provides a conservative means of predicting long-term release from monolithic waste forms, offering a simple and relatively quick means of determining effective solid diffusion coefficients. As presented here, these coefficients can be used in a simple model to predict maximum release rates or be used in more complex site-specific models to predict actual site performance. For waste forms that pass the structural integrity test, this model also allows the prediction of EP-Tox leachate concentrations from these coefficients. Thus, the results of the ANS 16.1 Leach Procedure provide a powerful tool that can be used to predict the waste concentration limits in order to comply with the EP-Toxicity criteria for characteristically nonhazardous waste. 12 refs., 3 figs

  2. Leaching from denture base materials in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Lygre, H.; Solheim, E.; Gjerdet, N.R. [School of Medicine, Univ. of Bergen (Norway)

    1995-04-01

    Specimens made from denture base materials were leached in Ringer Solution and in ethanol. The specimens comprised a heat-cured product processed in two different ways and two cold-cured materials. The organic compounds leaching from the specimens to the solutions were separated, identified, and quantified by a combined gas-chromatography and gas-chromatography/mass-spectrometry technique. Additives and degradation products, possibly made by free radical reactions, were released from the denture base materials. In Ringer solution only phthalates could be quantified. In ethanol solvent, biphenyl, dibutyl phthalate, dicyclohexyl phthalate, phenyl benzoate, and phenyl salicylate were quantified. In addition, copper was found in the ethanol solvent from one of the denture base materials. The amount of leachable organic compounds varies among different materials. Processing temperature influences the initial amount of leachable compounds. 36 refs., 7 figs., 1 tab.

  3. Modeling long-term leaching experiments of full scale cemented wastes: effect of solution composition on diffusion

    International Nuclear Information System (INIS)

    Borkel, C.; Montoya, V.; Kienzler, B.

    2015-01-01

    The code PHREECQ V3.1 has been used to simulate leaching experiments performed with cemented simulated waste products in tap water for more than 30 years. In this work the main focus is related with the leaching of Cs explained by diffusion processes. A simplifying model using the code PHREECQ V3.1 was used to investigate the influence of different parameters on the release of Cs from the cement solid to the leaching solution. The model setup bases on four main assumptions: a) the solid as well as the distribution of Cs is homogeneous and of isotropic texture, b) there is no preferential direction regarding cement degradation or water intrusion into the solid, c) the pore space is entirely connected and d) Cs adsorption to the cement or container is negligible. In the modeling the constraint of charge balance was stressed. Effective diffusion coefficients (D e ) were obtained analytically and from modeling the diffusive release of Cs from cemented waste simulates. The obtained values D e for Cs leaching are in perfect agreement with the values published in literature. Contradictory results to diffusive release were obtained from XRD analysis of the solids, suggesting that water may not have penetrated the cement monoliths entirely, but only to some centimeters depth. XRD analysis have been done to determine the solid phases present in cement and are used to help outlining strength and weaknesses of the different models

  4. Leaching of saltstones containing fly ash

    International Nuclear Information System (INIS)

    Barnes, M.W.; Roy, D.M.; Langton, C.A.

    1985-01-01

    Two types of fly ash were incorporated in saltstones designed for potential encapsulation of Savannah River Plant low level defense waste. These fly ashes have some cementitious properties while at the same time their presence in substitution for cement slows early hydration. Class C fly ash has a high calcium content and is considered cementitious; Class F fly ash has a low calcium content and is not classified as cementitious. Leach tests were performed and physical properties were measured for saltstones containing each class, to see the differences in the effect of the fly ashes. The four waste ions nitrate, nitrite, sodium and sulfate were shown to leach by diffusion. Effective diffusivities were determined for these ions. Data for nitrate, the most important species from the environmental point of view, are shown in Table A. Saltstones made with Class C fly ash have substantially lower leach rates than those made with Class F fly ash. The leach rates, and therefore the square roots of the effective diffusivities, have been found to be proportional to the pore surface area per unit volume (or the ratio of pore volume to pore radius), to the fraction of waste containing solution, and to the inverse of the fraction of calcium in the saltstone. Rates and diffusivities are not proportional to the water to cement ratio, because this number depends on whether the fly ash is counted as cementitious, as in Class C cement, or not cementitious, as in Class F cement. In fact the relatively small amount of calcium in Class F cement contributes to the cementitious properties overall, though not so much as Class C cement. 4 refs., 2 figs., 6 tabs

  5. Gold and Silver Extraction from Leach Solutions

    Directory of Open Access Journals (Sweden)

    Bagdaulet K. Kenzhaliyev

    2014-03-01

    Full Text Available There has been carried out an investigation on the extraction of gold and silver from thiosulfate solutions: standard test and technological solutions of chemical and electrochemical leaching. The influence of related metals on the process of extracting gold from solution was studied. There has been conducted a comparative study of the IR spectra of solutions after the sorption of gold, silver and related metals.

  6. Residues leaching from 'Factory of barren ores'

    International Nuclear Information System (INIS)

    Rakhmatov, N.; Khakimov, N.; Nazarov, Kh.M.; Barotov, A.M.

    2012-01-01

    The objective of the present work is safe management of residues from Factory of Barren Ores, their reprocessing, expenditures reduction for remediation of Istiklol city former uranium tailings. For this purpose, some experiences were adopted - Factory of Barren Ores tailing use for filling up the open pit where water with uranium content 3-5 mg/l is located. Factory of Barren Ores waste are passed through heap leaching and have some amount of uranium salts dissolved in water. Thus, we propose to dissolve uranium from Factory of Barren Ores wastes with uranium bearing water flowing out from gallery and filling up the open-pit by radioactive wastes. In so doing, uranium content flowing out from gallery will increase twice, and further, passing them through apricot's shell, as a sorbent, we will clean the water against radionuclides. Residue samples with uranium content 0,015% from Factory of Barren Ores and uranium bearing waters from gallery 1 with uranium content 0,0025 g/l were used for laboratory tests. After which, a slurry was prepared by means of residue mixing with water in ratio of solid and liquid phases (S:L) - 1:2 and 9,7 ml of sulfuric acid (Ρ=1,82) was added which corresponds consumption by H 2 SO 4 176,54 kg/t. For the first test, leaching was carried out during 4 hours at ph=1,6 at room temperature. For the second test, leaching was carried out at 60 d eg C a nd ph=1,6 during 4 hours. Slurry heating and mixing was carried out by means of magnetic mixer. The basic residue leaching indicators are provided in this article.

  7. Thiosulfate leaching of gold from sulfide wastes

    Energy Technology Data Exchange (ETDEWEB)

    Block-Bolten, A.; Torma, A.E.

    1986-07-01

    The kinetics of gold extraction from lead-zinc sulfide flotation tailings by thiosulfate leachants has been investigated. The order of reaction as well as the overall reaction rate constant were, with respect to thiosulfate concentration, calculated to be n=0.75 and k=1.05 x 10/sup -6/ mol/sup 1/4/ dm/sup 5/4/ min/sup -1/. The apparent activation energy was found to be ..delta..E/sub a/=48.53 kJ and the frequency factor A=7.5 x 10/sup 2/ mol dm/sup -3/ min/sup -1/. This activation energy value suggests chemical control of the reaction mechanism. Optimum leach temperature of 50/sup 0/C was established. Gold extractions as high as 99% have been realized in two step countercurrent leachings. Change in pH throughout the leaching process was found to be an excellent indicator for the progress of the extraction. A preliminary economic evaluation of the process is given.

  8. Economic leaching at Roessing Uranium Limited

    International Nuclear Information System (INIS)

    Johnson, C.C.

    1990-01-01

    In the fourteen years that Roessing Uranium Limited has been in production, the metallurgical operations and controls on the leaching plant have envolved through four basic stages. Initially, the emphasis was placed on the achievement of consistent plant operation by overcoming severe start-up difficulties. The second stage involved the attainment of the design operating targets and also the commissioning of the ferric-leaching reactors in order to achieve a ferric ion concentration of more than 3.0 g/l. Improvements in control then became the priority, with the emphasis on consistently achieving the target concentrations of ferric ions, total iron, and terminal acidity. The latest phase has concentrated on the optimization of costs by means of adjustments to the historically established operating parameters in order to achieve large savings on consumables while maintaining the leaching efficiencies. Apart from the obvious incentive of reducing costs in an inflationary economy and a depressed uranium market, impetus for this work was given by a change in the type of ore from the open pit, which has the effect of reducing the extraction efficiency while increasing the consumption of consumable materials. These problems and their solutions are discussed in detail, and the importance to cost-effective optimization of an accurate up-to-date cost-reporting structure is stressed. 9 figs., 2 tabs

  9. Modeling of facade leaching in urban catchments

    Science.gov (United States)

    Coutu, S.; Del Giudice, D.; Rossi, L.; Barry, D. A.

    2012-12-01

    Building facades are protected from microbial attack by incorporation of biocides within them. Flow over facades leaches these biocides and transports them to the urban environment. A parsimonious water quantity/quality model applicable for engineered urban watersheds was developed to compute biocide release from facades and their transport at the urban basin scale. The model couples two lumped submodels applicable at the basin scale, and a local model of biocide leaching at the facade scale. For the facade leaching, an existing model applicable at the individual wall scale was utilized. The two lumped models describe urban hydrodynamics and leachate transport. The integrated model allows prediction of biocide concentrations in urban rivers. It was applied to a 15 km2urban hydrosystem in western Switzerland, the Vuachère river basin, to study three facade biocides (terbutryn, carbendazim, diuron). The water quality simulated by the model matched well most of the pollutographs at the outlet of the Vuachère watershed. The model was then used to estimate possible ecotoxicological impacts of facade leachates. To this end, exceedance probabilities and cumulative pollutant loads from the catchment were estimated. Results showed that the considered biocides rarely exceeded the relevant predicted no-effect concentrations for the riverine system. Despite the heterogeneities and complexity of (engineered) urban catchments, the model application demonstrated that a computationally "light" model can be employed to simulate the hydrograph and pollutograph response within them. It thus allows catchment-scale assessment of the potential ecotoxicological impact of biocides on receiving waters.

  10. Study of the sulfuric acid leaching and bacterial leaching of low grade uranium ore by orbital shaker experiment

    International Nuclear Information System (INIS)

    Li Guangyue; Liu Yulong; Wang Yongdong; Ding Dexin

    2009-01-01

    The sulphuric acid leaching and bacteria leaching by orbital shaker experiments were conducted for the low grade uranium ore from a uranium mine in Guangdong Province. The results show that, when the concentration of sulphuric acid and that of slurry were 30 g/L and 25%, respectively, the conditions were most favourable for sulphuric acid leaching and the rate of leaching reached 92.92%, that, when pH value was 1.5, inoculation amount, 10%, concentration of slurry, 10%, the conditions were most favourable for bacteria leaching and the rate of leaching reached 95.93%, that, compared with sulphuric acid leaching, bacteria leaching decreased sulphuric acid consumption by 17.2% and increased the rate of leaching by 3%, and that, under the most favourable conditions for suphuric acid leaching, if 1% natrium chlorate was added, the rate of leaching increased to 96.46%, but 10 kg of natrium chlorate was consumed for 1 ton of uranium ore. (authors)

  11. Pesticide leaching through sandy and loamy fields – Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme

    International Nuclear Information System (INIS)

    Rosenbom, Annette E.; Olsen, Preben; Plauborg, Finn; Grant, Ruth; Juhler, René K.; Brüsch, Walter; Kjær, Jeanne

    2015-01-01

    The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. - Highlights: • Field-results reveal shortcomings in the EU authorization procedure for pesticides. • The plough layer can be bypassed via preferential transport in e.g. wormholes. • Pesticides properties are decisive for leaching pattern on the sandy fields. • The hydrogeological settings control the leaching patterns on the loamy fields. • Pesticide detection frequency seems to be independent of the month of the year. - Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme reveals shortcomings in the European Union authorization procedure for pesticides

  12. ArcCN-Runoff: An ArcGIS tool for generating curve number and runoff maps

    Science.gov (United States)

    Zhan, X.; Huang, M.-L.

    2004-01-01

    The development and the application of ArcCN-Runoff tool, an extension of ESRI@ ArcGIS software, are reported. This tool can be applied to determine curve numbers and to calculate runoff or infiltration for a rainfall event in a watershed. Implementation of GIS techniques such as dissolving, intersecting, and a curve-number reference table improve efficiency. Technical processing time may be reduced from days, if not weeks, to hours for producing spatially varied curve number and runoff maps. An application example for a watershed in Lyon County and Osage County, Kansas, USA, is presented. ?? 2004 Elsevier Ltd. All rights reserved.

  13. Long-term leaching from MSWI air-pollution-control residues: Leaching characterization and modeling

    DEFF Research Database (Denmark)

    Hyks, Jiri; Astrup, Thomas; Christensen, Thomas Højlund

    2009-01-01

    Long-term leaching of Ca, Fe, Mg, K, Na, S, Al, As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Mo, Sb, Si, Sri, Sr, Ti, V, P, Cl, and dissolved organic carbon from two different municipal solid waste incineration (MSWI) air-pollution-control residues was monitored during 24 months of column percolat......Long-term leaching of Ca, Fe, Mg, K, Na, S, Al, As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Mo, Sb, Si, Sri, Sr, Ti, V, P, Cl, and dissolved organic carbon from two different municipal solid waste incineration (MSWI) air-pollution-control residues was monitored during 24 months of column...... percolation experiments; liquid-to-solid (L/S) ratios of 200-250 L/kg corresponding to more than 10,000 years in a conventional landfill were reached. Less than 2% of the initially present As, Cu, Pb, Zn, Cr, and Sb had leached during the Course of the experiments. Concentrations of Cd, Fe, Mg, Hg, Mn, Ni, Co......, Sn, Ti, and P were generally bellow 1 mu g/L; overall less than 1% of their mass leached. Column leaching data were further used in a two-step geochemical modeling in PHREEQC in order to (i) identify solubility controlling minerals and (ii) evaluate their interactions in a water-percolated column...

  14. Leaching of uranium and thorium from monazite: III. Leaching of radiogenic daughters

    International Nuclear Information System (INIS)

    Olander, D.; Eyal, Y.

    1990-01-01

    The solid-state diffusion model of actinide leaching developed in Part II of this series is applied to leaching of radiogenic daughters of the actinide decay chains. For an untreated natural monazite, the direct leaching component of 228 Th release is larger than that for 232 Th because of enhanced solid-state mobility for 228 Th provided by 228 Ra-recoil tracks. A significant portion of the 228 Th which appears in the leachate, however, is attributed to decay of insoluble 228 Ra which is continually released from the mineral by matrix dissolution and recoil ejection. For a monazite sample that was annealed at 800 degree C prior to leaching, the bulk of the 228 Th in solution was supplied by decay of 228 Ra rejected from the mineral matrix during annealing. The radiogenic 234 U daughter of the 238 U decay chain did not exhibit similarly enhanced leaching because the long half-life of 234 U permitted local radiation damage to be annealed out at ambient temperature prior to 234 U decay

  15. Evaluation of ferrolysis in arsenate adsorption on the paddy soil derived from an Oxisol.

    Science.gov (United States)

    Jiang, Jun; Dai, Zhaoxia; Sun, Rui; Zhao, Zhenjie; Dong, Ying; Hong, Zhineng; Xu, Renkou

    2017-07-01

    Iron oxides are dominant effective adsorbents for arsenate in iron oxide-rich variable charge soils. Oxisol-derived paddy soils undergo intensive ferrolysis, which results in high leaching and transformation of iron oxides. However, little information is available concerning the effect of ferrolysis on arsenate adsorption by paddy soil and parent Oxisol. In the present study, we examined the arsenate affinity of soils using arsenate adsorption/desorption isotherms, zeta potential, adsorption kinetics, pH effect and phosphate competition experiments. Results showed that ferrolysis in an alternating flooding-drying Oxisol-derived paddy soil resulted in a significant decrease of free iron oxides and increase of amorphous iron oxides in the surface and subsurface layers. There were more reactive sites exposed on amorphous than on crystalline iron oxides. Therefore, disproportionate ratios of arsenate adsorption capacities and contents of free iron oxides were observed in the studied Oxisols compared with paddy soils. The Gibbs free energy values corroborated that both electrostatic and non-electrostatic adsorption mechanisms contributed to the arsenate adsorption by bulk soils, and the kinetic adsorption data further suggested that the rate-limiting step was chemisorption. The zeta potential of soil colloids decreased after arsenate was adsorbed on the surfaces, forming inner-sphere complexes and thus transferring their negative charges to the soil particle surfaces. The adsorption/desorption isotherms showed that non-electrostatic adsorption was the main mechanism responsible for arsenate binding to the Oxisol and derived paddy soils, representing 91.42-94.65% of the adsorption capacities. Further studies revealed that arsenate adsorption was greatly inhibited by increasing suspension pH and incorporation of phosphate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Assessment of some straw-derived materials for reducing the leaching potential of Metribuzin residues in the soil

    Energy Technology Data Exchange (ETDEWEB)

    Cara, Irina Gabriela, E-mail: coroirina@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3M. Sadoveanu Alley, 700490 Iasi (Romania); Trincă, Lucia Carmen, E-mail: lctrinca@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, 3 M. Sadoveanu Alley, 700490 Iasi (Romania); Trofin, Alina Elena, E-mail: aetrofin@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, 3 M. Sadoveanu Alley, 700490 Iasi (Romania); Cazacu, Ana, E-mail: anagarlea@gmail.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, 3 M. Sadoveanu Alley, 700490 Iasi (Romania); Ţopa, Denis, E-mail: topadennis@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3M. Sadoveanu Alley, 700490 Iasi (Romania); Peptu, Cătălina Anişoara, E-mail: catipeptu@yahoo.co.uk [“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 73 D. Mangeron Street, 700050 Iasi (Romania); Jităreanu, Gerard, E-mail: gerardj@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3M. Sadoveanu Alley, 700490 Iasi (Romania)

    2015-12-15

    Highlights: • Surface characteristics of activated straw (wheat, corn, soybean) were assessed. • Modification methods to enhance materials sorption were presented. • Adsorption mechanism of metribuzin was revealed and discussed. - Abstract: Biomass (straw waste) can be used as raw to obtain materials for herbicide removal from wastewater. These by-products have some important advantages, being environmentally friendly, easily available, presenting low costs, and requiring little processing to increase their adsorptive capacity. In the present study, some materials derived from agricultural waste (wheat, corn and soybean straw) were investigated as potential adsorbents for metribuzin removal from aqueous solutions. The straw wastes were processed by grinding, mineralisation (850 °C) and KOH activation in order to improve their functional surface activity. The materials surface characteristics were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The adsorbents capacity was evaluated using batch sorption tests and liquid chromatography coupled with mass spectrometry for herbicide determination. For adsorption isotherms, the equilibrium time considered was 3 h. The experimental adsorption data were modelled by Freundlich and Langmuir models. The activated straw and ash-derived materials from wheat, corn and soybean increased the adsorption capacity of metribuzin with an asymmetrical behaviour. Overall, our results sustain that activated ash-derived from straw and activated straw materials can be a valuable solution for reducing the leaching potential of metribuzin through soil.

  17. Assessment of some straw-derived materials for reducing the leaching potential of Metribuzin residues in the soil

    International Nuclear Information System (INIS)

    Cara, Irina Gabriela; Trincă, Lucia Carmen; Trofin, Alina Elena; Cazacu, Ana; Ţopa, Denis; Peptu, Cătălina Anişoara; Jităreanu, Gerard

    2015-01-01

    Highlights: • Surface characteristics of activated straw (wheat, corn, soybean) were assessed. • Modification methods to enhance materials sorption were presented. • Adsorption mechanism of metribuzin was revealed and discussed. - Abstract: Biomass (straw waste) can be used as raw to obtain materials for herbicide removal from wastewater. These by-products have some important advantages, being environmentally friendly, easily available, presenting low costs, and requiring little processing to increase their adsorptive capacity. In the present study, some materials derived from agricultural waste (wheat, corn and soybean straw) were investigated as potential adsorbents for metribuzin removal from aqueous solutions. The straw wastes were processed by grinding, mineralisation (850 °C) and KOH activation in order to improve their functional surface activity. The materials surface characteristics were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The adsorbents capacity was evaluated using batch sorption tests and liquid chromatography coupled with mass spectrometry for herbicide determination. For adsorption isotherms, the equilibrium time considered was 3 h. The experimental adsorption data were modelled by Freundlich and Langmuir models. The activated straw and ash-derived materials from wheat, corn and soybean increased the adsorption capacity of metribuzin with an asymmetrical behaviour. Overall, our results sustain that activated ash-derived from straw and activated straw materials can be a valuable solution for reducing the leaching potential of metribuzin through soil.

  18. Leaching potential of pervious concrete and immobilization of Cu, Pb and Zn using pervious concrete.

    Science.gov (United States)

    Solpuker, U; Sheets, J; Kim, Y; Schwartz, F W

    2014-06-01

    This paper investigates the leaching potential of pervious concrete and its capacity for immobilizing Cu, Pb and Zn, which are common contaminants in urban runoff. Batch experiments showed that the leachability of Cu, Pb and Zn increased when pHconcrete might function to attenuate contaminant migration. A porous concrete block was sprayed with low pH water (pH=4.3±0.1) for 190 h. The effluent was highly alkaline (pH~10 to 12). In the first 50 h, specific conductance and trace-metal were high but declined towards steady state values. PHREEQC modeling showed that mixing of interstitial alkaline matrix waters with capillary pore water was required in order to produce the observed water chemistry. The interstitial pore solutions seem responsible for the high pH values and relatively high concentrations of trace metals and major cations in the early stages of the experiment. Finally, pervious concrete was sprayed with a synthetic contaminated urban runoff (10 ppb Cu, Pb and Zn) with a pH of 4.3±0.1 for 135 h. It was found that Pb immobilization was greater than either Cu or Zn. Zn is the most mobile among three and also has the highest variation in the observed degree of immobilization. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Nitrate Leaching From a Mountain Forest Ecosystem with Gleysols Subjected to Experimentally Increased N Deposition

    International Nuclear Information System (INIS)

    Schleppi, Patrick; Hagedorn, Frank; Providoli, Isabelle

    2004-01-01

    Nitrate leaching was measured over seven years of nitrogen (N) addition in a paired-catchment experiment in Alptal, central Switzerland (altitude: 1200 m, bulk N deposition: 12 kg ha -1 a -1 ). Two forested catchments (1500 m 2 each) dominated by Picea abies) were delimited by trenches in the Gleysols. NH 4 NO 3 was added to one of the catchments using sprinklers. During the first year, the N addition was labelled with 15 N. Additionally, soil N transformations were studied in replicated plots. Pre-treatment NO 3 - -N leaching was 4 kg ha -1 a -1 from both catchments, and remained between 2.5 and 4.8 kg ha -1 a -1 in the control catchment. The first year of treatment induced an additional leaching of 3.1 kg ha -1 , almost 90% of which was labelled with 15 N, indicating that it did not cycle through the large N pools of the ecosystem (soil organic matter and plants). These losses partly correspond to NO 3 - from precipitation bypassing the soil due to preferential flow. During rain or snowmelt events, NO 3 - concentration peaks as the water table is rising, indicating flushing from the soil. Nitrification occurs temporarily along the water flow paths in the soil and can be the source of NO 3 - flushing. Its isotopic signature however, shows that this release mainly affects recently applied N, stored only between runoff events or up to a few weeks. At first, the ecosystem retained 90% of the added N (2/3 in the soil), but NO 3 - losses increased from 10 to 30% within 7 yr, indicating that the ecosystem became progressively N saturated

  20. Leaching of heavy metals from steelmaking slags

    Directory of Open Access Journals (Sweden)

    Gomes, J. F. P

    2006-12-01

    Full Text Available Leaching tests with EAF and Ladle slags were performed, using a flow through test and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. The chemical analysis of the leachates during this period shows, in general, for both types of slag, an increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slag samples submitted to these trials presented very low total leaching levels. The most extracted elements are calcium and magnesium. Nevertheless, in flow-through test, calcium and magnesium leached from solid slags are below 0.5% and all other metals below 0.1%. Leachates obtained with DIN 38414-S4 present, as expected, higher leaching values; however, these are inferior to 5 % (Ca and 1% (other elements.

    Este articulo contiene los resultados obtenidos en ensayos de lixiviación de escorias de acero (horno electrico y cuchara ejecutados siguiendo la metodologia de flujo dinámico así como el ensayo normalizado DIN 38414-S4. El primer ensayo intenta simular el comportamiento de lixiviación de las escorias en vertedero. Para las escorias ensayadas se han complementado los ensayos con el análisis químico de los lixiviados y se ha verificado un aumento de la liberación de metales pesados. El ensayo DIN 38414-S4 se ha utilizado para evaluar la lixiviación por agua de metales pesados, en muestras de escorias originales. Despues de un año de ensayos, se han observado niveles muy bajos de lixiviación. Los elementos mas lixiviados han sido calcio y magnesio. No obstante, en los ensayos de flujo dinámico, el calcio y el magnesio lixiviados de las escorias sólidas era menor de 0,5% y el resto de los otros metales era inferior a 0,1%. Los lixiviados obtenidos con el ensayo DIN 38414-S4 presentan, como era de esperar, valores

  1. Pelletized ponderosa pine bark for adsorption of toxic heavy metals from water

    Science.gov (United States)

    Miyoung Oh; Mandla A. Tshabalala

    2007-01-01

    Bark flour from ponderosa pine (Pinus ponderosa) was consolidated into pellets using citric acid as cross-linking agent. The pellets were evaluated for removal of toxic heavy metals from synthetic aqueous solutions. When soaked in water, pellets did not leach tannins, and they showed high adsorption capacity for Cu(ll), Zn(ll), Cd(ll). and Ni(ll) under both equilibrium...

  2. Treatment of atrazine in nursery irrigation runoff by a constructed wetland.

    Science.gov (United States)

    Runes, Heather B; Jenkins, Jeffrey J; Moore, James A; Bottomley, Peter J; Wilson, Bruce D

    2003-02-01

    To investigate the treatment capability of a surface flow wetland at a container nursery near Portland, Oregon, atrazine was introduced during simulated runoff events. Treatment efficiency was evaluated as the percent atrazine recovered (as percent of applied) in the water column at the wetland's outlet. Atrazine treatment efficiency at the outlet of the constructed wetland during a 7-d period ranged from 18-24% in 1998 (experiments 1-3) and 16-17% in 1999 (experiments 4 and 5). Changes in total flow, or frequency and intensity of runoff events did not affect treatment. For experiment 6 in 1999, where the amount, frequency, and duration of runoff events exceeded all other experiments, treatment was compromised. For all experiments, deethylatrazine (DEA) and deisopropylatrazine (DIA) accounted for 13-21% of the initial application. Hydroxyatrazine (HA) was rarely detected in the water. Organic carbon adsorption coefficients (Koc) were determined from batch equilibrium sorption isotherms with wetland sediment, and they decreased in the order of HA > DIA > atrazine > DEA. Static water-sediment column experiments indicated that sorption is an important mechanism for atrazine loss from water passing through the constructed wetland. The results of the MPN assay indicated the existence in the wetland of a low-density population of microorganisms with the potential to mineralize atrazine's ethyl side chain.

  3. Adsorption of 137Cs on titanium ferrocyanide and transformation of the sorbent to lithium titanate. A new method for long term immobilization of 137Cs

    International Nuclear Information System (INIS)

    Barbara Bartos; Barbara Filipowicz; Monika Lyczko; Aleksander Bilewicz

    2014-01-01

    Dynamic adsorption of radiocesium on titanium ferrocyanide grains from reactor coolant simulating solution containing salts at moderate concentrations has been investigated. Effective decontamination of the neutral solutions has been achieved, in the amounts of a more than 20 thousand bed volumes. After adsorption the titanium ferrocyanide was transferred to titanates and calcined at 900 deg C. The leaching test of the obtained lithium titanates indicates that the loaded adsorbent can serve as an effective primary barrier in nuclear waste repositories. (author)

  4. Adsorption of 137Cs on titanium ferrocyanide and transformation of the sorbent to lithium titanate: a new method for long term immobilization of 137Cs.

    Science.gov (United States)

    Bartoś, Barbara; Filipowicz, Barbara; Łyczko, Monika; Bilewicz, Aleksander

    Dynamic adsorption of radiocesium on titanium ferrocyanide grains from reactor coolant simulating solution containing salts at moderate concentrations has been investigated. Effective decontamination of the neutral solutions has been achieved, in the amounts of a more than 20 thousand bed volumes. After adsorption the titanium ferrocyanide was transferred to titanates and calcined at 900 °C. The leaching test of the obtained lithium titanates indicates that the loaded adsorbent can serve as an effective primary barrier in nuclear waste repositories.

  5. Regenerative adsorption distillation system

    KAUST Repository

    Ng, Kim Choon

    2013-12-26

    There is provided a regenerative adsorption distillation system comprising a train of distillation effects in fluid communication with each other. The train of distillation effects comprises at least one intermediate effect between the first and last distillation effects of the train, each effect comprising a vessel and a condensing tube for flow of a fluid therein. The system further comprises a pair of adsorption-desorption beds in vapour communication with the last effect and at least one intermediate effect, wherein the beds contain an adsorbent that adsorbs vapour from the last effect and transmits desorbed vapour into at least one of the intermediate effect.

  6. Regenerative adsorption distillation system

    KAUST Repository

    Ng, Kim Choon; Thu, Kyaw; Amy, Gary; Chunggaze, Mohammed; Al-Ghasham, Tawfiq

    2013-01-01

    There is provided a regenerative adsorption distillation system comprising a train of distillation effects in fluid communication with each other. The train of distillation effects comprises at least one intermediate effect between the first and last distillation effects of the train, each effect comprising a vessel and a condensing tube for flow of a fluid therein. The system further comprises a pair of adsorption-desorption beds in vapour communication with the last effect and at least one intermediate effect, wherein the beds contain an adsorbent that adsorbs vapour from the last effect and transmits desorbed vapour into at least one of the intermediate effect.

  7. Bayesian analyses of seasonal runoff forecasts

    Science.gov (United States)

    Krzysztofowicz, R.; Reese, S.

    1991-12-01

    Forecasts of seasonal snowmelt runoff volume provide indispensable information for rational decision making by water project operators, irrigation district managers, and farmers in the western United States. Bayesian statistical models and communication frames have been researched in order to enhance the forecast information disseminated to the users, and to characterize forecast skill from the decision maker's point of view. Four products are presented: (i) a Bayesian Processor of Forecasts, which provides a statistical filter for calibrating the forecasts, and a procedure for estimating the posterior probability distribution of the seasonal runoff; (ii) the Bayesian Correlation Score, a new measure of forecast skill, which is related monotonically to the ex ante economic value of forecasts for decision making; (iii) a statistical predictor of monthly cumulative runoffs within the snowmelt season, conditional on the total seasonal runoff forecast; and (iv) a framing of the forecast message that conveys the uncertainty associated with the forecast estimates to the users. All analyses are illustrated with numerical examples of forecasts for six gauging stations from the period 1971 1988.

  8. Determination of characteristics maximal runoff Mountain Rivers

    African Journals Online (AJOL)

    Ovcharuk V and Todorova O

    Odessa State Environmental University, Ukraine. Received: 03 December 2015 / Accepted: 23 April 2016 / Published online: 01 May 2016. ABSTRACT. This article has been examined maximum runoff of the rivers of the Crimean Mountains. The rivers flow through the western and eastern part of the northern slope Crimean ...

  9. Characterization of chromium species in urban runoff

    DEFF Research Database (Denmark)

    Cederkvist, Karin; Jensen, Marina Bergen; Holm, Peter Engelund

    2013-01-01

    Little is known about the presence of the element Cr in its toxic hexavalent form Cr(VI) in stormwater runoff from urban areas. Most studies report only total Cr concentration, i.e., including also the nontoxic Cr(III) molecular form. The objective of this study was to evaluate a field method bas...

  10. Contaminants in urban runoff to Norwegian fjords

    Energy Technology Data Exchange (ETDEWEB)

    Jartun, Morten [Geological Survey of Norway, Trondheim (Norway); Pettersen, Arne [Norwegian Geotechnical Inst., Oslo (Norway)

    2010-03-15

    Introduction: Sediments from urban stormwater runoff have been collected and analyzed for the content of various contaminants in harbor areas of Harstad, Trondheim, Bergen, and Drammen, Norway. Materials and methods: The concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), tributyltin, heavy metals, and total organic carbon were determined in most samples. This study provides substantial empirical data on the active, ongoing dispersion of pollutants from land-based sources in an urban area toward the marine environments in Norway. Results and discussion: The results of the analyses clearly demonstrate the importance of the urban environment representing a variety of contamination sources, and that stormwater runoff is an important dispersion mechanism of toxic pollutants. Conclusion: The concentrations of different contaminants in the urban runoff sediments show that there are several active pollution sources supplying the runoff systems with PCBs, PAHs (including benzo(a)pyrene, B(a)p), and heavy metals such as lead, mercury, zinc, and cadmium. This study describe the usefulness of the methods on how to examine ongoing urban contamination of harbors and similar recipients before any remediation plan for improving the environmental condition of marine sediments is effectuated. (orig.)

  11. Rainwater runoff from building facades : a review

    NARCIS (Netherlands)

    Blocken, B.J.E.; Derome, D.; Carmeliet, J.E.

    2013-01-01

    Rainwater runoff from building facades is a complex process governed by a wide range of urban, building, material and meteorological parameters. Given this complexity and the wide range of influencing parameters, it is not surprising that despite research efforts spanning over almost a century,

  12. Green Roofs for Stormwater Runoff Control

    Science.gov (United States)

    This project evaluated green roofs as a stormwater management tool. Specifically, runoff quantity and quality from green and flat asphalt roofs were compared. Evapotranspiration from planted green roofs and evaporation from unplanted media roofs were also compared. The influence...

  13. Landscape runoff, precipitation variation and reservoir limnology

    OpenAIRE

    Geraldes, Ana Maria

    2010-01-01

    Landscape runoff potential impact on reservoir limnology was indirectly evaluated by assessing the effect of precipitation variation on several water quality parameters, on Anabaena (Cyanophyta) and crustacean zooplankton abundances. The obtained results showed that total phosphorus increased with strong precipitation events whereas water transparency presented an opposite trend. Wet periods followed by long dry periods favored Anabaena dominance, which induced a...

  14. water infiltration, conductivity and runoff under fallow

    African Journals Online (AJOL)

    Measurements of runoff was done during the long rains of. 2003 and short rains of 2004. Infiltration was invariably higher under agroforestry systems (P<0.001) than sole cropping, particularly under Alnus and Calliandra systems. A similar pattern was observed for saturated hydraulic conductivity (Ksat), which was greater in ...

  15. Simplified Laboratory Runoff Procedure (SLRP): Procedure and Application

    National Research Council Canada - National Science Library

    Price, Richard

    2000-01-01

    The Simplified Laboratory Runoff Procedure (SLRP) was developed to provide a faster, less expensive approach to evaluate surface runoff water quality from dredged material placed in an upland environment...

  16. Urban runoff and combined sewer overflow. [Wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Moffa, P.E. (Calocerinos and Spina, Liverpool, NY); Freedman, S.D.; Owens, E.M.; Field, R.; Cibik, C.

    1982-06-01

    The control, treatment and management of urban runoff and sewer overflow are reviewed. Simplified modeling and monitoring techniques are used to characterize urban runoff and to assess control alternatives. (KRM)

  17. Properties of calcium depleted hydrated cement paste: mineralogical characterization and cesium adsorption

    International Nuclear Information System (INIS)

    Babaahmadi, A.; Tang, L.; Zareen, A.

    2015-01-01

    Understanding the changes in adsorption properties of cementitious barriers and the effect on the release of radio-nuclides to the environment during the service life of the repository is of high importance. A major degradation scenario within safety assessment analysis of nuclear waste repositories is decalcification of cementitious materials due to long-term contact with groundwater. In order to decrease the uncertainty in the simulation of this process due to extrapolating short term data sets based on short term experimental analysis, acceleration methods enhancing the decalcification process can be used. However it is not yet completely proved that how different the properties of the aged samples through accelerated leaching is compared to the samples aged in natural ageing process. In this study the changes in cesium adsorption of the hydrated cement paste due to calcium depletion is taken in to consideration. The aged samples are prepared with application of an accelerating electro-chemical migration method. The mineralogical properties of decalcified specimens are characterized to demonstrate their comparability with naturally leached samples. The gradual effect of migration function on cementitious materials indicates a relatively homogenous leaching in cementitious specimens and a considerable increase in specific surface area due to the leaching of calcium. It is concluded that the aged samples having a larger surface area and less calcium and alkalis ions compared to pristine materials, exhibit a higher binding potential for Cs ions

  18. Process for controlling calcium in a leach operation

    International Nuclear Information System (INIS)

    Habib, E.J.

    1982-01-01

    A method for controlling calcium, e.g. calcite, build-up in the leach solution of a uranium and/or related values recovery operation wherein the leach solution is flowed through a value bearing ore to dissolve the desired values. A soluble fluoride, e.g. sodium fluoride, is added to the leach solution after it has passed through the ore to thereby precipitate calcium fluoride from the leach solution and lower the calcium content of the leach solution. The soluble fluoride may be added to the leach solution before the leach solution passes through the process equipment which is used to remove the values from the leach solution or the soluble fluoride may be added after the leach solution passes through the process equipment. If added before, it is preferable to also add a carbonate/bicarbonate solution along with the soluble fluoride to prevent coprecipitation of uranyl/desired value fluoride or to redissolve coprecipitated fluoride back into the leach solution

  19. Continuous-flow leaching studies of crushed and cored SYNROC

    International Nuclear Information System (INIS)

    Coles, D.G.; Bazan, F.

    1982-01-01

    Both crushed (150- to 300- μm) and cored (1,8- mm-diam) samples of SYNROC have been leached with single-pass continuous-flow leaching equipment. Crushed samples of cesium-hollandite were also leached in a similar experiment. Temperatures used were 25 0 and 75 0 C and leachates were 0.03 N NaHCO 3 and distilled water. Leaching rates from SYNROC-C were ranked cesium > strontium greater than or equal to calcium > barium > zirconium. A comparison of leaching rates is made between crushed SYNROC, cored SYNROC, and Pacific Northwest Laboratory 76-68 glass beads. This comparison depends on how the surface areas are determined for each sample. Based on geometric surface areas for SYNROC cores and glass beads, cesium leach rates from SYNROC compare well with both sodium and neptunium leached from the glass. The other elements leached from SYNROC are lower than sodium and neptunium leached from glass. They also vary for each element, while glass shows nearly the same leach rate for both sodium and neptunium

  20. Continuous-flow leaching studies of crushed and cored SYNROC

    International Nuclear Information System (INIS)

    Coles, D.G.; Bazan, F.

    1981-01-01

    Both crushed (150 to 300 μm) and cored (1.8 mm diameter) samples of SYNROC have been leached with the single-pass continuous-flow leaching equipment. Crushed samples of Cs-hollandite were also leached in a similar experiment. Temperatures used were 25 and 75 0 C and leachates were 0.03 N NaHCO 3 and distilled water. Leaching rates from SYNROC C were ranked Cs > Sr greater than or equal to Ca > Ba > Zr. A comparison of leaching rates is made between crushed SYNROC, cored SYNROC, and PNL 76-68 glass beads. This comparison depends on how the surface areas are determined for each sample. Based on geometric surface areas for SYNROC cores and glass beads Cs leach rates from SYNROC compare well with both Na and Np leached from the glass. The other elements leached from SYNROC are lower than Na and Np leached from glass. They also vary for each element while glass shows nearly the same leach rate for both Na and Np

  1. Groundwater leaching of neutralized and untreated acid-leached uranium-mill tailings

    International Nuclear Information System (INIS)

    Gee, G.W.; Begej, C.W.; Campbell, A.C.; Sauter, N.N.; Opitz, B.E.; Sherwood, D.R.

    1981-01-01

    Tailings neutralization was examined to determine the effect of neutralization on contaminant release. Column leaching of acid extracted uranium mill tailings from Exxon Highland Mill, Wyoming, Pathfinder Gas Hills Mill, Wyoming, and the Dawn Midnite Mill, Washington, resulted in the flushing of high concentrations of salts in the first four pore volumes of leachate, followed by a steady decrease to the original groundwater salt concentrations. Neutralization decreased the concentration of salts and radionuclides leaching from the tailings and decreased the volume of solution required to return the solution to the groundwater pH and EC. Radium-226 and uranium-238 leached quickly from the tailings in the initial pore volumes of both neutralized and unneutralized tailings, and then decreased significantly. 6 figures, 5 tables

  2. Surface runoff in the Itaim Watershed

    Directory of Open Access Journals (Sweden)

    Getulio Teixeira Batista

    2007-06-01

    Full Text Available This paper describes a work done in the Itaim watershed at Taubaté, SP, and had the objective of estimating the surface runoff based on the Curve-Number (CN method in area with vegetation cover of grassland (Brachiaria Decumbens, that prevails in this watershed. The surface runoff was estimated using three different methods: 1st values of accumulated Infiltration (IAc obtained in the field were used, considered as the Potential Infiltration (S, which varied from 15.37 mm to 51.88 mm with an average value of 23.46 mm. With those measured infiltration rates and using the maximum precipitation values for Taubaté, SP, with duration time of 3 hours: P = 54.4; 70.3; 80.8; 86.7; 90.9; 94.1 and 103.9 mm, respectively, for the return times, Tr = 2, 5, 10, 15, 25, 50 and 100 years, the following values of surface runoff were generated: 34.83; 49.33; 59.14; 64.71; 68.69; 71.73 and 81.10 mm, respectively; In the 2nd method it was considered that the prevailing vegetation cover of the watershed was Dirty Pasture (Pasture with regrowth of natural vegetation and therefore, a value of CN = 75 was used and generated a potential infiltration, S = 84,7 mm and resulted in surface runoff values that varied from 11 to 44 mm; In the 3rd method, the value of CN was considered equal to 66.57. This value was calculated weighting the contribution of all land use cover classes of the watershed, and as a result a higher value of potential infiltration, S = 127 mm, was obtained. Consequently, the surface runoff values were 5.33; 11.64; 16.72; 19.83; 22.16; 23.98 and 29.83 mm, respectively. Therefore, the comparison with the results obtained by the two Curve-Number methods (conventional and weighted allowed to be concluded that the Curve-Number method applied in a conventional way underestimated the surface runoff in the studied area. However, results indicate that it is possible to use this method for surface runoff estimates as long as adjustments based on potential

  3. Development of an accelerated leaching method for incineration bottom ash correlated to toxicity characteristic leaching protocol.

    Science.gov (United States)

    Lin, Shengxuan; Zhou, Xuedong; Ge, Liya; Ng, Sum Huan; Zhou, Xiaodong; Chang, Victor Wei-Chung

    2016-10-01

    Heavy metals and some metalloids are the most significant inorganic contaminants specified in toxicity characteristic leaching procedure (TCLP) in determining the safety of landfills or further utilization. As a consequence, a great deal of efforts had been made on the development of miniaturized analytical devices, such as Microchip Electrophoresis (ME) and μTAS for on-site testing of heavy metals and metalloids to prevent spreading of those pollutants or decrease the reutilization period of waste materials such as incineration bottom ash. However, the bottleneck lied in the long and tedious conventional TCLP that requires 18 h of leaching. Without accelerating the TCLP process, the on-site testing of the waste material leachates was impossible. In this study, therefore, a new accelerated leaching method (ALM) combining ultrasonic assisted leaching with tumbling was developed to reduce the total leaching time from 18 h to 30 min. After leaching, the concentrations of heavy metals and metalloids were determined with ICP-MS or ICP-optical emission spectroscopy. No statistical significance between ALM and TCLP was observed for most heavy metals (i.e., cobalt, manganese, mercury, molybdenum, nickel, silver, strontium, and tin) and metalloids (i.e., arsenic and selenium). For the heavy metals with statistical significance, correlation factors derived between ALM and TCLP were 0.56, 0.20, 0.037, and 0.019 for barium, cadmium, chromium, and lead, respectively. Combined with appropriate analytical techniques (e.g., ME), the ALM can be applied to rapidly prepare the incineration bottom ash samples as well as other environmental samples for on-site determination of heavy metals and metalloids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. A Theory of Strategic Voting in Runoff Elections

    OpenAIRE

    Laurent Bouton

    2013-01-01

    This paper analyzes the properties of runoff electoral systems when voters are strategic. A model of three-candidate runoff elections is presented, and two new features are included: the risk of upset victory in the second round is endogenous, and many types of runoff systems are considered. Three main results emerge. First, runoff elections produce equilibria in which only two candidates receive a positive fraction of the votes. Second, a sincere voting equilibrium does not always exist. Fin...

  5. Specifics of surface runoff contents and treatment in large cities

    OpenAIRE

    V.N. Chechevichkin; N.I. Vatin

    2014-01-01

    The degree of surface runoff pollution in large cities has been assessed in modern conditions in the case study of production sites of St. Petersburg. Increased content of petroleum derivatives and heavy metal ions both in rainwater runoff and especially in snowmelt runoff has been revealed. It has been established that the composition of infiltration runoff from the newly built-up sites within the city limits commonly depends on their background, especially in the places of former unaut...

  6. Further insight into the mechanism of heavy metals partitioning in stormwater runoff.

    Science.gov (United States)

    Djukić, Aleksandar; Lekić, Branislava; Rajaković-Ognjanović, Vladana; Veljović, Djordje; Vulić, Tatjana; Djolić, Maja; Naunovic, Zorana; Despotović, Jovan; Prodanović, Dušan

    2016-03-01

    Various particles and materials, including pollutants, deposited on urban surfaces are washed off by stormwater runoff during rain events. The interactions between the solid and dissolved compounds in stormwater runoff are phenomena of importance for the selection and improvement of optimal stormwater management practices aimed at minimizing pollutant input to receiving waters. The objective of this research was to further investigate the mechanisms responsible for the partitioning of heavy metals (HM) between the solid and liquid phases in urban stormwater runoff. The research involved the collection of samples from urban asphalt surfaces, chemical characterization of the bulk liquid samples, solids separation, particle size distribution fractionation and chemical and physico-chemical characterization of the solid phase particles. The results revealed that a negligible fraction of HM was present in the liquid phase (less than 3% by weight), while there was a strong correlation between the total content of heavy metals and total suspended solids. Examinations of surface morphology and mineralogy revealed that the solid phase particles consist predominantly of natural macroporous materials: alpha quartz (80%), magnetite (11.4%) and silicon diphosphate (8.9%). These materials have a low surface area and do not have significant adsorptive capacity. These materials have a low surface area and do not have significant adsorptive capacity. The presence of HM on the surface of solid particles was not confirmed by scanning electron microscopy and energy dispersive X-ray microanalyses. These findings, along with the results of the liquid phase sample characterization, indicate that the partitioning of HM between the liquid and solid phases in the analyzed samples may be attributed to precipitation processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Physical adsorption and molecular dynamics

    International Nuclear Information System (INIS)

    Cohan, N.V.

    1981-01-01

    Some aspects of noble gases adsorption (except He) on graphite substracts are reviewed. Experimental results from this adsorption are analyzed and compared with molecular dynamics calculations. (L.C.) [pt

  8. Experimental study on bio-leaching of high sulphuric acid consumption uranium ore by adding sulphide

    International Nuclear Information System (INIS)

    Meng Yunsheng; Zheng Ying; Liu Hui; Cheng Hao; Zhou Lei; Liu Chao; Fan Baotuan; Li Jianhua

    2012-01-01

    In order to decrease acid consumption and increase leaching rate, an experiment on bio-leach-ing of low grade uranium ore by adding sulphide was done. Compared with conventional leaching method, the leaching rate of uranium is improved by 3% and the leaching period was reduced to 60 days from 90 days by bio-leaching method of adding sulphide. In order to decrease acid consumption with bio-leaching by adding sulphide obviously, robust bacteria to sulphide should be chosen. (authors)

  9. 49 CFR 213.59 - Elevation of curved track; runoff.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Elevation of curved track; runoff. 213.59 Section... track; runoff. (a) If a curve is elevated, the full elevation shall be provided throughout the curve, unless physical conditions do not permit. If elevation runoff occurs in a curve, the actual minimum...

  10. Determination of characteristics maximal runoff mountain rivers in ...

    African Journals Online (AJOL)

    ... water) on the rivers of the Crimean Mountains were used materials of observations for long-term period (from the beginning of observations to 2010 inclusive) on 54 of streamflow station with using a the so-called «operator» model for maximum runoff formation. Keywords: maximum runoff; rain floods; hillslope runoff; karst ...

  11. Improving runoff risk estimates: Formulating runoff as a bivariate process using the SCS curve number method

    Science.gov (United States)

    Shaw, Stephen B.; Walter, M. Todd

    2009-03-01

    The Soil Conservation Service curve number (SCS-CN) method is widely used to predict storm runoff for hydraulic design purposes, such as sizing culverts and detention basins. As traditionally used, the probability of calculated runoff is equated to the probability of the causative rainfall event, an assumption that fails to account for the influence of variations in soil moisture on runoff generation. We propose a modification to the SCS-CN method that explicitly incorporates rainfall return periods and the frequency of different soil moisture states to quantify storm runoff risks. Soil moisture status is assumed to be correlated to stream base flow. Fundamentally, this approach treats runoff as the outcome of a bivariate process instead of dictating a 1:1 relationship between causative rainfall and resulting runoff volumes. Using data from the Fall Creek watershed in western New York and the headwaters of the French Broad River in the mountains of North Carolina, we show that our modified SCS-CN method improves frequency discharge predictions in medium-sized watersheds in the eastern United States in comparison to the traditional application of the method.

  12. Sulfate adsorption on goethite

    Energy Technology Data Exchange (ETDEWEB)

    Rietra, R P.J.J.; Hiemstra, T; Riemsdijk, W.H. van

    1999-10-15

    Recent spectroscopic work has suggested that only one surface species of sulfate is dominant on hematite. Sulfate is therefore a very suitable anion to test and develop adsorption models for variable charge minerals. The authors have studied sulfate adsorption on goethite covering a large range of sulfate concentrations, surface coverages, pH values, and electrolyte concentrations. Four different techniques were used to cover the entire range of conditions. For characterization at low sulfate concentrations, below the detection limit of sulfate with ICP-AES, the authors used proton-sulfate titrations at constant pH. Adsorption isotherms were studied for the intermediate sulfate concentration range. Acid-base titrations in sodium sulfate and electromobility were used for high sulfate concentrations. All the data can be modeled with one adsorbed species if it is assumed that the charge of adsorbed sulfate is spatially distributed in the interface. The charge distribution of sulfate follows directly from modeling the proton-sulfate adsorption stoichoimemtry sine this stoichiometry is independent of the intrinsic affinity constant of sulfate. The charge distribution can be related to the structure of the surface complex by use of the Pauling bond valence concept and is in accordance with the microscopic structure found by spectroscopy. The intrinsic affinity constant follows from the other measurements. Modeling of the proton-ion stoichoimetry with the commonly used 2-pK models, where adsorbed ions are treated as point charges, is possible only if at least two surface species for sulfate are used.

  13. Phosphorus leaching in a soil textural gradient

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Kjærgaard, Charlotte; Rubæk, Gitte Holton

    2009-01-01

    Texture is a major factor influencing mobilization and transport of P in soil owing partly to differences in adsorptive properties, and partly to differences in pore-size distribution and pore organization. Slurry application strategies may be important mitigation measures for reducing agricultur...

  14. Leaching of 210Po in human saliva from smokeless tobacco

    International Nuclear Information System (INIS)

    Syed, U.F.; Bari, A.; Husain, L.; Husain, L.

    2009-01-01

    Use of smokeless tobacco (SLT) is associated with cancer of the oral cavity. 210 Po, a known carcinogen present in SLT may leach into the saliva when the snuff is held in the mouth. Alpha emission from leached 210 Po can cause oral tissue damage, especially in the presence of non healing ulcers seen frequently in snuff users' mouth. Leaching of 210 Po from SLT in human saliva was determined for six popular US snuff brands. 210 Po was leached into human saliva for 30 min, separated radiochemically and its activity was determined by α-counting. Approximately 2-10% of 210 Po present in SLT was observed to leach. Annual exposure from leached 210 Po, based on average daily consumption of 15 g of SLT, was calculated to range from 1.1 to 3.8 Bq year -1 . (author)

  15. Continuous-flow leaching studies of crushed and cored SYNROC

    International Nuclear Information System (INIS)

    Coles, D.G.; Bazan, F.

    1980-01-01

    Both crushed (150 to 300 μm) and cored 1.8 mm diameter) samples of SYNROC have been leached with the single-pass continuous-flow leaching equipment. Crushed samples of Cs-hollandite were also leached in a similar experiment. Temperatures used were 25 0 C and 75 0 C and leachates were 0.03 N NaHCO 3 and distilled water. Leaching rates from SYNROC C were ranked Cs > Sr greater than or equal to Ca > Ba > Zr. A comparison of leaching rates is made between crushed SYNROC, cored SYNROC, and PNL 76-68 glass beads. Problems encountered when comparing the leaching rates of different waste forms are discussed

  16. Comparison of oxidants in alkaline leaching of uranium ore

    International Nuclear Information System (INIS)

    Sreenivas, T.; Rajan, K.C.; Srinivas, K.; Anand Rao, K.; Manmadha Rao, M.; Venkatakrishnan, R.R.; Padmanabhan, N.P.H.

    2007-01-01

    The uranium minerals occurring in various ore deposits consists of predominantly uranous ion (U +4 ), necessitating use of an oxidant and other lixiviants for efficient dissolution during leaching. Unlike acid leaching route, where uranium minerals dissolution could be achieved efficiently with cheaper lixiviants, processing of ores by alkaline leaching route involve expensive lixiviants and drastic leaching conditions. Alkaline leaching of uranium ores becomes economical only upon using cheaper and efficient oxidants and conservation of other reagents by their recycle. The present paper gives efficacy of various oxidants - KMnO 4 , NaOCl, Cu - NH 3 , air and oxygen, in the leaching of uranium from a low-grade dolostone hosted uranium ore of India. A comparison based on technical merits and cost of the oxidant chemicals is discussed. (author)

  17. Chlorine-assisted leaching of Key Lake uranium ore

    International Nuclear Information System (INIS)

    Haque, K.E.

    1981-04-01

    Bench-scale chlorine-assisted leach tests were conducted on the Key Lake uranium ore. Leach tests conducted at 80 0 C on a slurry containing 50% solids during 10 hours of agitation gave the maximum extraction of uranium - 96% and radium-226 - 91%. Chlorine was added at 23.0 Kg Cl 2 /tonne of ore to maintain the leach slurry pH in the range of 1.5-1.0. To obtain residue almost free of radionuclides, hydrochloric acid leaches were conducted on the first stage leach residues. The second stage leach residue still was found to contain uranium - 0.0076% and radium-226 - 200 pCi/g of solids

  18. Selective Adsorption of Uranium (VI) on NaHCO 3 Leached ...

    African Journals Online (AJOL)

    Ion imprinted nano-magnetic composite polymers for selective removal of hexavalent uranium were prepared by a precipitation polymerization technique in the presence of γ-methacryloxypropyltrimethoxysilane (γ-MPS) coated magnetite and other pre-polymerization reagents. The synthesized magnetic polymers were then ...

  19. Thiosulphate leaching of gold-, silver-, copper flotation concentrates

    International Nuclear Information System (INIS)

    Samikhov, Sh.R.; Zinchenko, Z.A.

    2015-01-01

    Present article is devoted to thiosulphate leaching of gold-, silver-, copper flotation concentrates. For the purpose to improve the process of thiosulphate leaching the ore samples were calcined at temperature 600 ℃ during two hours. During the calcination process of gold-sulphide ores and concentrates the minerals pyrite and arsenopyrite oxidize which lead to opening of gold contains in them. It was defined that thiosulphate leaching can be recommended as an alternative to cyanic process.

  20. Preparation and leaching of radioactive INEL waste forms

    International Nuclear Information System (INIS)

    Schuman, R.P.; Welch, J.M.; Staples, B.A.

    1982-01-01

    The purpose of this study is to prepare and leach test ceramic and glass waste form specimens produced from actual transuranic waste sludges and high-level waste calcines, respectively. Description of wastes, specimen fabrication, leaching procedure, analysis of leachates and results are discussed. The conclusion is that radioactive waste stored at INEL can be readily incorporated in fused ceramic and glass forms. Initial leach testing results indicate that these forms show great promise for safe long-term containment of radioactive wastes

  1. Leaching of DOC, DN, and inorganic constituents from scrap tires.

    Science.gov (United States)

    Selbes, Meric; Yilmaz, Ozge; Khan, Abdul A; Karanfil, Tanju

    2015-11-01

    One concern for recycle and reuse of scrap tires is the leaching of tire constituents (organic and inorganic) with time, and their subsequent potential harmful impacts in environment. The main objective of this study was to examine the leaching of dissolved organic carbon (DOC), dissolved nitrogen (DN), and selected inorganic constituents from scrap tires. Different sizes of tire chips and crumb rubber were exposed to leaching solutions with pH's ranging from 3.0 to 10.0 for 28days. The leaching of DOC and DN were found to be higher for smaller size tire chips; however, the leaching of inorganic constituents was independent of the size. In general, basic pH conditions increased the leaching of DOC and DN, whereas acidic pH conditions led to elevated concentrations of metals. Leaching was minimal around the neutral pH values for all the monitored parameters. Analysis of the leaching rates showed that components associated with the rubbery portion of the tires (DOC, DN, zinc, calcium, magnesium, etc.) exhibited an initial rapid followed by a slow release. On the other hand, a constant rate of leaching was observed for iron and manganese, which are attributed to the metal wires present inside the tires. Although the total amounts that leached varied, the observed leaching rates were similar for all tire chip sizes and leaching solutions. Operation under neutral pH conditions, use of larger size tire chips, prewashing of tires, and removal of metal wires prior to application will reduce the impact of tire recycle and reuse. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Commercial application of bacterial heap leaching in Ganzhou uranium mine

    International Nuclear Information System (INIS)

    Liu Jian; Fan Baotuan; Meng Yunsheng; Xiao Jinfeng; Chen Sencai; Wu Jinjing; Liu Chengwu; Wu Yichang; Zeng Ruilong

    2003-01-01

    In this paper the situation of commercial application on bacterial heap leaching in Ganzhou Uranium Mine is introduced, and the construction of biomembrane oxidizing tank, regeneration and recycled utilization of barren solution are summarized. Total five heaps, 18436 t, uranium ore are leached by bacteria during the half of a year. The result is consistent with that of commercial experiment. The technology of bacterial heap leaching is more perfected

  3. Aquifer restoration techniques for in-situ leach uranium mines

    International Nuclear Information System (INIS)

    Deutsch, W.J.; Bell, N.E.; Mercer, B.W.; Serne, R.J.; Shade, J.W.; Tweeton, D.R.

    1984-02-01

    In-situ leach uranium mines and pilot-scale test facilities are currently operating in the states of Wyoming, Texas, New Mexico and Colorado. This report summarizes the technical considerations involved in restoring a leached ore zone and its aquifer to the required level. Background information is provided on the geology and geochemistry of mineralized roll-front deposits and on the leaching techniques used to extract the uranium. 13 references, 13 figures, 4 tables

  4. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lanigan, David C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westsik, Joseph H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jung, H. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-08-12

    This revision to the original report adds two longer term leach sets of data to the report and provides more discussion and graphics on how to interpret the results from long-term laboratory leach tests. The leach tests were performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams.

  5. Radiotracer investigation in gold leaching tanks

    Energy Technology Data Exchange (ETDEWEB)

    Dagadu, C.P.K., E-mail: dagadukofi@yahoo.co.uk [Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana); Akaho, E.H.K.; Danso, K.A. [Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana); Stegowski, Z.; Furman, L. [Faculty of Physics and Applied Computer Science, AGH-UST, 30-059 Krakow (Poland)

    2012-01-15

    Measurement and analysis of residence time distribution (RTD) is a classical method to investigate performance of chemical reactors. In the present investigation, the radioactive tracer technique was used to measure the RTD of aqueous phase in a series of gold leaching tanks at the Damang gold processing plant in Ghana. The objective of the investigation was to measure the effective volume of each tank and validate the design data after recent process intensification or revamping of the plant. I-131 was used as a radioactive tracer and was instantaneously injected into the feed stream of the first tank and monitored at the outlet of different tanks. Both sampling and online measurement methods were used to monitor the tracer concentration. The results of measurements indicated that both the methods provided identical RTD curves. The mean residence time (MRT) and effective volume of each tank was estimated. The tanks-in-series model with exchange between active and stagnant volume was used and found suitable to describe the flow structure of aqueous phase in the tanks. The estimated effective volume of the tanks and high degree of mixing in tanks could validate the design data and confirmed the expectation of the plant engineer after intensification of the process. - Highlights: Black-Right-Pointing-Pointer I-131 radioactive tracer is suitable for tracing the aqueous phase in gold ore slurry. Black-Right-Pointing-Pointer Online data collection is more convenient method for tracer monitoring in industrial process systems. Black-Right-Pointing-Pointer The tanks-in-series model with exchange between active and stagnant zones is suitable to describe the flow behavior of leaching tanks. Black-Right-Pointing-Pointer The radiotracer RTD technique could be used to validate design data after process intensification in gold leaching tanks.

  6. Probable leaching mechanisms for spent fuel

    International Nuclear Information System (INIS)

    Wang, R.; Katayama, Y.B.

    1981-01-01

    At the Pacific Northwest Laboratory, researchers in the Waste/Rock Interaction Technology Program are studying spent fuel as a possible waste form for the Office of Nuclear Waste Isolation. This paper presents probable leaching mechanisms for spent fuel and discusses current progress in identifying and understanding the leaching process. During the past year, experiments were begun to study the complex leaching mechanism of spent fuel. The initial work in this investigation was done with UO 2 , which provided the most information possible on the behavior of the spent-fuel matrix without encountering the very high radiation levels associated with spent fuel. Both single-crystal and polycrystalline UO 2 samples were used for this study, and techniques applicable to remote experimentation in a hot cell are being developed. The effects of radiation are being studied in terms of radiolysis of water and surface activation of the UO 2 . Dissolution behavior and kinetics of UO 2 were also investigated by electrochemical measurement techniques. These data will be correlated with those acquired when spent fuel is tested in a hot cell. Oxidation effects represent a major area of concern in evaluating the stability of spent fuel. Dissolution of UO 2 is greatly increased in an oxidizing solution because the dissolution is then controlled by the formation of hexavalent uranium. In solutions containing very low oxygen levels (i.e., reducing solutions), oxidation-induced dissolution may be possible via a previously oxidized surface, through exposure to air during storage, or by local oxidants such as O 2 and H 2 O 2 produced from radiolysis of water and radiation-activated UO 2 surfaces. The effects of oxidation not only increase the dissolution rate, but could lead to the disintegration of spent fuel into fine fragments

  7. Impact of weather variability on nitrate leaching

    Science.gov (United States)

    Richards, Karl; Premrov, Alina; Hackett, Richard; Coxon, Catherine

    2016-04-01

    The loss of nitrate (NO3 - N) to water via leaching and overland flow contributes to eutrophication of freshwaters, transitional and near coastal waters with agriculture contributing significantly to nitrogen (N) loading to these water. Environmental regulations, such as the Nitrates and Water Framework Directives, have increased constraints on farmers to improve N management in regions at risk of NO3--N loss to water. In addition, farmers also have to manage their systems within a changing climate as the imapcts of climate change begin to impact resulting in more frequent extreme events such as floods and droughts. The objective of this study was to investigate the link between weather volatility and the concentration of leached NO3--N spring barley. Leaching was quantified under spring barley grown on a well-drained, gravelly sandy soil using ceramic cup samplers over 6 drainage years under the same farming practices and treatments. Soil solution NO3--N concentrations under spring barley grown by conventional inversion ploughing and reduced tillage were compared to weather parameters over the period. Weather was recorded at a national Met Eireann weather station on site. Soil solution NO3--N varied significantly between years. Within individual years NO3--N concentrations varied over the drainage season, with peak concentrations generally observed in the autumn time, decreasing thereafter. Under both treatments there was a three-fold difference in mean annual soil solution NO3--N concentration over the 6 years with no change in the agronomic practices (crop type, tillage type and fertiliser input). Soil solution nitrate concentrations were significantly influenced by weather parameters such as rainfall, effective drainage and soil moisture deficit. The impact of climate change in Ireland could lead to increased NO3--N loss to water further exacerbating eutrophication of sensitive estuaries. The increased impact on eutrophication of waters, related to climatic

  8. Radiotracer investigation in gold leaching tanks

    International Nuclear Information System (INIS)

    Dagadu, C.P.K.; Akaho, E.H.K.; Danso, K.A.; Stegowski, Z.; Furman, L.

    2012-01-01

    Measurement and analysis of residence time distribution (RTD) is a classical method to investigate performance of chemical reactors. In the present investigation, the radioactive tracer technique was used to measure the RTD of aqueous phase in a series of gold leaching tanks at the Damang gold processing plant in Ghana. The objective of the investigation was to measure the effective volume of each tank and validate the design data after recent process intensification or revamping of the plant. I-131 was used as a radioactive tracer and was instantaneously injected into the feed stream of the first tank and monitored at the outlet of different tanks. Both sampling and online measurement methods were used to monitor the tracer concentration. The results of measurements indicated that both the methods provided identical RTD curves. The mean residence time (MRT) and effective volume of each tank was estimated. The tanks-in-series model with exchange between active and stagnant volume was used and found suitable to describe the flow structure of aqueous phase in the tanks. The estimated effective volume of the tanks and high degree of mixing in tanks could validate the design data and confirmed the expectation of the plant engineer after intensification of the process. - Highlights: ► I-131 radioactive tracer is suitable for tracing the aqueous phase in gold ore slurry. ► Online data collection is more convenient method for tracer monitoring in industrial process systems. ► The tanks-in-series model with exchange between active and stagnant zones is suitable to describe the flow behavior of leaching tanks. ► The radiotracer RTD technique could be used to validate design data after process intensification in gold leaching tanks.

  9. RMDF leach-field decontamination. Final report

    International Nuclear Information System (INIS)

    Carroll, J.W.; Marzec, J.M.; Stelle, A.M.

    1982-01-01

    The objective of the decontamination effort was to place the Radioactive Materials Disposal Facility (RMDF) leach field in a condition suitable for release for unrestricted use. Radioactively contaminated soil was excavated from the leach field to produce a condition of contamination as low as reasonably achievable (ALARA). The contaminated soil was boxed and shipped to an NRC-licensed burial site at Beatty, Nevada, and to the DOE burial site at Hanford, Washington. The soil excavation project successfully reduced the contamination level in the leach field to background levels, except for less than 0.6 mCi of Sr-90 and trace amounts of Cs-137 that are isolated in cracks in the bedrock. The cracks are greater than 10 ft below the surface and have been sealed with a bituminous asphalt mastic. A pathways analysis for radiation exposure to humans from the remaining radionuclides was performed, assuming intensive home gardening, and the results show that the total first year whole body dose equivalent would be about 0.1 mrem/year. This dose equivalent is a projection for the hypothetical ingestion of vegetables grown on the site. Assuming that an average adult consumes 64 kg of green leafy vegetables per year and that the entire yearly supply could be grown on the site, the amount of ingested Sr-90 and Cs-137 is calculated to be 1100 pCi/year and 200 pCi/year. This ingested quantity would produce a total first year whole body dose equivalent of 0.10 mrem, using the accepted soil-to-plant transfer factors of 0.0172 and 0.010 for Sr-90 and Cs-137, respectively. The whole body dose equivalent exposure value of 0.1 mrem/year is far below the tentative limit established by NRC of 5 mrem/year for areas released for unrestricted use

  10. Runoff and soil loss from bench terraces. 1. An event-based model of rainfall infiltration and surface runoff.

    NARCIS (Netherlands)

    van Dijk, A.I.J.M.; Bruijnzeel, L.A.

    2004-01-01

    Overland flow resulting from an excess of rain over infiltration is an essential component of many models of runoff and erosion from fields or catchments. The spatially variable infiltration (SVI) model and a set of associated equations relating depth of runoff and maximum rate of 'effective' runoff

  11. Use of biomass sorbents for oil removal from gas station runoff.

    Science.gov (United States)

    Khan, Eakalak; Virojnagud, Wanpen; Ratpukdi, Thunyalux

    2004-11-01

    The use of biomass sorbents, which are less expensive and more biodegradable than synthetic sorbents, for oil removal from gas station runoff was investigated. A bench-scale flume experiment was conducted to evaluate the oil removal and retention capabilities of the biomass sorbents which included kapok fiber, cattail fiber, Salvinia sp., wood chip, rice husk, coconut husk, and bagasse. Polyester fiber, a commercial synthetic sorbent, was also experimented for comparison purpose. Oil sorption and desorption tests were performed at a water flow rate of 20 lmin-1. In the oil sorption tests, a 50 mgl(-1) of used engine oil-water mixture was synthesized to simulate the gas station runoff. The mass of oil sorbed for all sorbents, except coconut husk and bagasse, was greater than 70%. Cattail fiber and polyester fiber were the sorbents that provided the least average effluent oil concentrations. Oil selectivity (hydrophobic properties) and physical characteristics of the sorbents are the two main factors that influence the oil sorption capability. The used sorbents from the sorption tests were employed in the desorption tests. Results indicated that oil leached out of all the sorbents tested. Polyester fiber released the highest amount of oil, approximately 4% (mass basis) of the oil sorbed. copyright 2004 Elsevier Ltd.

  12. Solubility limits of importance to leaching

    International Nuclear Information System (INIS)

    Ogard, A.; Bentley, G.; Bryant, E.; Duffy, C.; Grisham, J.; Norris, E.; Orth, C.; Thomas, K.

    1981-01-01

    The solubilities of some radionuclides, especially rare earths and actinides, may be an important and controlling factor in leaching of waste forms. These solubilities should be measured accurately as a function of pH and not as a part of a multicomponent system. Individual solubilities should be measured as a function of temperature to determine if a kinetic effect is being observed in the data. A negative temperature coefficient of solubility for actinides and rare earths in water would have important consequences for nuclear reactor safety and for the management of nuclear wastes

  13. Leaching of TCIPP from furniture foam is rapid and substantial.

    Science.gov (United States)

    Stubbings, William A; Harrad, Stuart

    2018-02-01

    A series of laboratory experiments were conducted, in which waste furniture polyurethane foam samples containing tris (1-chloro-2-propyl) phosphate (TCIPP) were contacted with a range of leaching fluids, formulated to simulate the composition of landfill leachate. Leaching was examined under a number of different scenarios, such as: dissolved humic matter concentration, pH, and temperature, as well as the effect of agitation, and waste:leaching fluid contact duration. In addition to single batch (no replenishment of leaching fluid), serial batch (draining of leachate and replenishment with fresh leaching fluid at various time intervals) experiments were conducted. Leaching of TCIPP from PUF appears to be a first order process. Concentrations of TCIPP in leachate generated by the experiments in this study ranged from 13 mg L -1 to 130 mg L -1 . In serial batch leaching experiments, >95% of TCIPP was depleted from PUF after 168 h total contact with leaching fluid. Our experiments indicate leaching is potentially a very significant pathway of TCIPP emissions to the environment. Copyright © 2017. Published by Elsevier Ltd.

  14. Development of improved leaching techniques for vitrified radioactive waste products

    International Nuclear Information System (INIS)

    Vaswani, G.A.; Yeotikar, R.G.; Rastogi, R.C.; Sunder Rajan, N.S.

    1979-01-01

    A critical review of the current techniques for evaluating the leach resistance of vitrified radioactive wastes has been made. Inadequacy of the available leaching techniques, with respect to their adoption as standard technique on an international scale, has been brought out for the three broad catagories of aqueous attack viz., (i) simple contact with leachant at a particular temperature, (ii) once-through or recirculatory flow of leachant at variable temperatures and flow rates, and (iii) contact with freshly distilled hot water in soxhelet type of extractor. In an effort to evolve a standard leaching technique in the latter two categories of aqueous attack, development of two leaching units viz., 'Dynamic Leaching Unit' and 'Modified Soxhlet Unit' is described. Both these units offer good control and wide flexibility on the important parameters affecting leaching such as leachant temperature, flow rate of residence time of leachant and ratio of leachant volume to sample surface area. The dynamic leaching units also offers a good control and flexibility on the two additional parameters viz., the composition and pH of the leachant. In the modified soxhlet unit the composition and pH of the leachant remains near to that of distilled water. The leach rate results have been found to be reproducible. A need for framing the set of standard conditions for adoption of these units in evolution of standard leaching techniques has been indicated. (auth.)

  15. Accelerated Leach Test(s) Program. Annual report

    International Nuclear Information System (INIS)

    Dougherty, D.R.; Fuhrmann, M.; Colombo, P.

    1985-09-01

    This report summarizes the work performed for the Accelerated Leach Test(s) Program at Brookhaven National Laboratory in Fiscal Year 1985 under the sponsorship of the US Department of Energy's Low-Level Waste Management Program (LLWMP). Programmatic activities were concentrated in three areas, as listed and described in the following paragraphs. (1) A literature survey of reported leaching mechanisms, available mathematical models and factors that affect leaching of LLW forms has been compiled. Mechanisms which have been identified include diffusion, dissolution, ion exchange, corrosion and surface effects. Available mathematical models are based on diffusion as the predominant mechanism. Although numerous factors that affect leaching have been identified, they have been conveniently categorized as factors related to the entire leaching system, to the leachant or to the waste form. A report has been published on the results of this literature survey. (2) A computerized data base of LLW leaching data and mathematical models is being developed. The data are being used for model evaluation by curve fitting and statistical analysis according to standard procedures of statistical quality control. (3) Long-term tests on portland cement, bitumen and vinyl ester-styrene (VES) polymer waste forms are underway which are designed to identify and evaluate factors that accelerate leaching without changing the mechanisms. Results on the effect of temperature on leachability indicate that the leach rates of cement and VES waste forms increase with increasing temperature, whereas, the leach rate of bitumen is little affected

  16. Leach testing of Idaho Chemical Processing Plant final waste forms

    International Nuclear Information System (INIS)

    Schuman, R.P.

    1980-01-01

    A number of pellets and highly durable glasses prepared from nonradioactive-simulated high-level wasste calcines have been leach tested. The leach tests are patterned on the IAEA standard test and the proposed Materials Characterization Center tests. Most tests are made with static distilled water at 25, 70, 95, 250, and 350 0 C and in refluxing distilled water, Soxhlet, at 95 0 C. Leach rates are determined by analyzing the leachate by instrumental activation analysis or spectrochemical analysis and from weight loss. Leaches are run on glass using cast and core drilled cylinders, broken pieces and coarse ground material. Sample form has a considerable effect on leach rates; solid pieces gave higher leach rates than ground glass when expressed in g/cm 2 /day. Cesium, molybdenum and weight loss leach rates of cast glass cylinders in distilled water varied from -7 g/cm 7 /day at 25 0 C to approx. 10 -3 g/cm 2 /day at 250 0 C. The leach rates in static distilled water at 95 0 C were considerably lower than those in refluxing distilled water, Soxhlet, at the same temperature. Even at 25 0 C, sodium, cesium, and molybdenum readily leached from the porous pellets, but the pellets showed no visible attack, even at 250 0 C

  17. Microbial leaching of low grade sandstone uranium ores: column leaching studies

    International Nuclear Information System (INIS)

    Bhatti, T.M.; Malik, K.A.; Khalid, A.M.

    1991-01-01

    Microbial leaching studies on a low-grade sandstone uranium ore from Baghalchur Ore Deposits, D. G. Khan, Pakistan, containing 0.027 % U/sub 3/O/sub 8/ for extraction of uranium, were conducted in columns. Baghalchur sandstone uranium ore which is alkaline in nature, contained 5.0% calcite [CaCo/sub 3/], 2-3 % Fe/sub 2/O/sub 3/ and pyrite [FeS/sub 2/] less than 0.1 %. The ore amended with sulfur and/or sulfur slag as external energy source was found to leach with indigenous microflora mostly belonging to the genus Thiobacillus which are present in the uranium mine water. Column leaching studies revealed that when the ore was amended with elemental sulfur and irrigated with mine water (pH 3.5) 53 % U/sub 3/O/sub 8/ could be solubilized from it. However, when the natural mine water was used as such (pH 7.4) the solubilization of uranium was decreased to 41 % U/sub 3/O/sub 8/ in 90 days under similar conditions of percolation rate and temperature. The addition of (NH/sub 4/)/sub 2/SO/sub 4/ (3.0 g/L) in mine water was found to enhance the uranium leaching to 70 % U/sub 3/O/sub 8/ from the columns containing ore amended with sulfur slag. (author)

  18. Uranium leaching from phosphatic sandstone and shale of Qatrani using citrate as a new leaching reagent

    International Nuclear Information System (INIS)

    Hussein, E.M.

    1997-01-01

    Uranium is found in Qatrani area (Southwest of Cairo and North of lake Qarun) in various forms in sedimentary rocks. Two important ore materials have been chosen for studying the recovery of their uranium contents namely; the phosphatic sandstone and the carbonaceous shale. The main emphasis in this thesis is the choice of an acid that would selectively leach uranium from thesis ores while leaving calcium phosphate and carbonate minerals minerals almost completely intact. Citric acid was indeed found advantageous due primarily to its strong ability to form stable complexes with uranium over a wide range of PH values beside the possibility of controlling thr solubility of calcium-bearing compounds by adding calcium citrate. The latter is actually characterized by its ability to exist in an unionized or associated from in citric acid solutions. From the general leaching characteristics of both uranium and P 2 O 5 from Qatrani phosphatic sandstone by citric acid, it was found that uranium could be completely leached beside the possibility of realizing a differential leaching percent values vs P 2 O 5 which is generally of limited solubility. Such a low solubility of P 2 O 5 has even been completely inhibited by providing calcium citrate to the citric acid solutions in amounts sufficient to exist in an optimum ionized non-associated state. Such a provision would render the solution unable to carry any further calcium ions thus the breakdown of the phosphate mineral was hindered while uranium has completely been selectively

  19. Taoshan uranium ore fields in situ blasting heap leaching rate influence factors to investigate

    International Nuclear Information System (INIS)

    Xie Wangnan; Dong Chunming

    2014-01-01

    Taoshan ore field ore in situ blasting heap leaching out build industrial test and production process, stope leaching rate and leaching cycle is large than that, after analysis, blasting method and cloth liquid way is to affect leaching rate and leaching cycle of the main factors. This paper holds that as far as possible using stratified deep hole blasting of squeezing up ways to reduce the building pile of in-situ leaching ore block rate; Adopting effective cloth tube way, increase the leaching agent and ore contact comprehensive; Introduction of bacterial leaching, and other means to improve leaching rate, shorten production cycle, etc to solve it. (authors)

  20. Nutrient Concentrations and Stable Isotopes of Runoff from a Midwest Tile-Drained Corn Field

    Science.gov (United States)

    Wilkins, B. P.; Woo, D.; Li, J.; Michalski, G. M.; Kumar, P.; Conroy, J. L.; Keefer, D. A.; Keefer, L. L.; Hodson, T. O.

    2017-12-01

    Tile drains are a common crop drainage device used in Midwest agroecosystems. While efficient at drainage, the tiles provide a quick path for nutrient runoff, reducing the time available for microbes to use nutrients (e.g., NO3- and PO43-) and reduce export to riverine systems. Thus, understanding the effects of tile drains on nutrient runoff is critical to achieve nutrient reduction goals. Here we present isotopic and concentration data collected from tile drain runoff of a corn field located near Monticello, IL. Tile flow samples were measured for anion concentrations and stable isotopes of H2O and NO3-, while precipitation was measured for dual isotopes of H2O. Results demonstrate early tile flow from rain events have a low Cl- concentration (60% contribution) in the beginning of the hydrograph. As flow continues H2O isotopic values reflect pre-event water (ground and soil water), and Cl- concentrations increase representing a greater influence by matrix flow (60-90% contribution). Nitrate concentrations change dramatically, especially during the growing season, and do not follow a similar trend as the conservative Cl-, often decreasing days before, which represents missing nitrate in the upper surface portion of the soil. Nitrate isotopic data shows significant changes in 15N (4‰) and 18O (4‰) during individual hydrological events, representing that in addition to plant uptake and leaching, considerate NO3- is lost through denitrification. It is notable, that throughout the season d15N and d18O of nitrate change significantly representing that seasonally, substantial denitrification occurs.

  1. Detection and attribution of nitrogen runoff trend in China's croplands.

    Science.gov (United States)

    Hou, Xikang; Zhan, Xiaoying; Zhou, Feng; Yan, Xiaoyuan; Gu, Baojing; Reis, Stefan; Wu, Yali; Liu, Hongbin; Piao, Shilong; Tang, Yanhong

    2018-03-01

    Reliable detection and attribution of changes in nitrogen (N) runoff from croplands are essential for designing efficient, sustainable N management strategies for future. Despite the recognition that excess N runoff poses a risk of aquatic eutrophication, large-scale, spatially detailed N runoff trends and their drivers remain poorly understood in China. Based on data comprising 535 site-years from 100 sites across China's croplands, we developed a data-driven upscaling model and a new simplified attribution approach to detect and attribute N runoff trends during the period of 1990-2012. Our results show that N runoff has increased by 46% for rice paddy fields and 31% for upland areas since 1990. However, we acknowledge that the upscaling model is subject to large uncertainties (20% and 40% as coefficient of variation of N runoff, respectively). At national scale, increased fertilizer application was identified as the most likely driver of the N runoff trend, while decreased irrigation levels offset to some extent the impact of fertilization increases. In southern China, the increasing trend of upland N runoff can be attributed to the growth in N runoff rates. Our results suggested that increased SOM led to the N runoff rate growth for uplands, but led to a decline for rice paddy fields. In combination, these results imply that improving management approaches for both N fertilizer use and irrigation is urgently required for mitigating agricultural N runoff in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Experiment on bio-leaching of associated molybdenum and uranium ore

    International Nuclear Information System (INIS)

    Zheng Ying; Fan Baotuan; Liu Jian; Meng Yunsheng; Liu Chao

    2007-01-01

    Column leaching experiment results on associated molybdenum uranium ore by bacteria (T. f) are introduced. The ore are leached for 210 days using bacteria domesticated to tolerate molybdenum, the leaching of uranium is of 98% and leaching of molybdenum is of 41%. Sulphuric acid produced by bio-oxidation of sulfides in ore can meet the demand of ore leaching. (authors)

  3. Fundamentals of high pressure adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.P.; Zhou, L. [Tianjin University, Tianjin (China). High Pressure Adsorption Laboratory

    2009-12-15

    High-pressure adsorption attracts research interests following the world's attention to alternative fuels, and it exerts essential effect on the study of hydrogen/methane storage and the development of novel materials addressing to the storage. However, theoretical puzzles in high-pressure adsorption hindered the progress of application studies. Therefore, the present paper addresses the major theoretical problems that challenged researchers: i.e., how to model the isotherms with maximum observed in high-pressure adsorption; what is the adsorption mechanism at high pressures; how do we determine the quantity of absolute adsorption based on experimental data. Ideology and methods to tackle these problems are elucidated, which lead to new insights into the nature of high-pressure adsorption and progress in application studies, for example, in modeling multicomponent adsorption, hydrogen storage, natural gas storage, and coalbed methane enrichment, was achieved.

  4. RUNOFF POTENTIAL OF MUREŞ RIVER UPPER BASIN TRIBUTARIES

    Directory of Open Access Journals (Sweden)

    V. SOROCOVSCHI

    2012-03-01

    Full Text Available Runoff Potential of Mureş River Upper Basin Tributaries. The upper basin of the Mureş River includes a significant area of the Eastern Carpathians central western part with different runoff formation conditions. In assessing the average annual runoff potential we used data from six gauging stations and made assessments on three distinct periods. Identifying the appropriate areas of the obtained correlations curves (between specific average runoff and catchments mean altitude allowed the assessment of potential runoff at catchment level and on geographical units. The potential average runoff is also assessed on altitude intervals of the mentioned areas. The runoff potential analysis on hydrographic basins, geographical units and altitude intervals highlights the variant spatial distribution of this general water resources indicator in the different studied areas.

  5. Nonlinear response in runoff magnitude to fluctuating rain patterns.

    Science.gov (United States)

    Curtu, R; Fonley, M

    2015-03-01

    The runoff coefficient of a hillslope is a reliable measure for changes in the streamflow response at the river link outlet. A high runoff coefficient is a good indicator of the possibility of flash floods. Although the relationship between runoff coefficient and streamflow has been the subject of much study, the physical mechanisms affecting runoff coefficient including the dependence on precipitation pattern remain open topics for investigation. In this paper, we analyze a rainfall-runoff model at the hillslope scale as that hillslope is forced with different rain patterns: constant rain and fluctuating rain with different frequencies and amplitudes. When an oscillatory precipitation pattern is applied, although the same amount of water may enter the system, its response (measured by the runoff coefficient) will be maximum for a certain frequency of precipitation. The significant increase in runoff coefficient after a certain pattern of rainfall can be a potential explanation for the conditions preceding flash-floods.

  6. Leaching of plastic additives to marine organisms

    International Nuclear Information System (INIS)

    Koelmans, Albert A.; Besseling, Ellen; Foekema, Edwin M.

    2014-01-01

    It is often assumed that ingestion of microplastics by aquatic species leads to increased exposure to plastic additives. However, experimental data or model based evidence is lacking. Here we assess the potential of leaching of nonylphenol (NP) and bisphenol A (BPA) in the intestinal tracts of Arenicola marina (lugworm) and Gadus morhua (North Sea cod). We use a biodynamic model that allows calculations of the relative contribution of plastic ingestion to total exposure of aquatic species to chemicals residing in the ingested plastic. Uncertainty in the most crucial parameters is accounted for by probabilistic modeling. Our conservative analysis shows that plastic ingestion by the lugworm yields NP and BPA concentrations that stay below the lower ends of global NP and BPA concentration ranges, and therefore are not likely to constitute a relevant exposure pathway. For cod, plastic ingestion appears to be a negligible pathway for exposure to NP and BPA. - Highlights: • Uptake of plastic additives after plastic ingestion was modeled for worms and fish. • This was done for bisphenol A and nonylphenol. • Uncertainty was accounted for by Monte Carlo simulations. • It appeared that exposure by plastic ingestion was negligible for fish. • Plastic ingestion may occasionally be relevant for marine worms. - Leaching of nonylphenol and bisphenol A from ingested microplastic may be relevant for the lugworm, but is irrelevant for fish like cod

  7. YACON INULIN LEACHING DURING HOT WATER BLANCHING

    Directory of Open Access Journals (Sweden)

    Caroline Fenner Scher

    2015-10-01

    Full Text Available ABSTRACTYacon roots contain inulin, which has prebiotic properties and it may be used as sucrose or fat substitutes. However, inulin is very soluble in water. The loss of this important nutrient during blanching is caused mainly by diffusion or leaching, which might be diminished if blanching temperature - time conditions are correctly employed. The aim of this study was to determine the leaching of the sugars inulin, glucose and fructose, present in yacon roots, during hot water blanching under different time/temperature conditions. The samples were cleaned and peeled and cut into geometric forms of 1.75 ± 0.35 mm thick disks. A complete factorial experimental design was used, and the treatments of the samples were compared using the Tukey test. The results indicated that the time and temperature were significant in the dissolution of the sugars. The lowest inulin losses occurred at temperatures and times lower than 60 ºC and 3 minutes. For all temperatures, the lowest glucose and fructose losses were obtained at time lower than 3 and 5 minutes, respectively.

  8. The recovery of gold from refractory ores by the use of carbon-in-chlorine leaching

    Science.gov (United States)

    Greaves, John N.; Palmer, Glenn R.; White, William W.

    1990-09-01

    Recently, the U.S. Bureau of Mines examined the recovery of gold by chlorination of refractory carbonaceous and sulfidic ores, comparing various treatment methods in which a ground ore pulp is contacted with chlorine gas and activated carbon is added to the pulp for a carbon-in-chlorine leach (CICL). The objective of this research was to demonstrate the basic feasibility of CICL technology. Results showed that the organic carbon deactivating environment of CICL lowers, but does not eliminate, the adsorption of gold on activated carbon. In this environment, the refractory ore is altered, and gold is extracted and then recovered on activated carbon. With highly carbonaceous ores, CICL achieved a higher recovery than with primarily sulfidic refractory ores. Basic cyanide amenability testing of two carbonaceous ores achieved recoveries of only 5.5% and 46%. With CICL treatment, recoveries on carbon were 90% and 92%.

  9. Influence of Cattle Trails on Runoff Quantity and Quality.

    Science.gov (United States)

    Miller, Jim J; Curtis, Tony; Chanasyk, David S; Willms, Walter D

    2017-03-01

    Cattle trails in grazed pastures close to rivers may adversely affect surface water quality of the adjacent river by directing runoff to it. The objective of this 3-yr study (2013-2015) in southern Alberta, Canada, was to determine if cattle trails significantly increased the risk of runoff and contaminants (sediment, nutrients) compared with the adjacent grazed pasture (control). A portable rainfall simulator was used to generate artificial rainfall (140 mm h) and runoff. The runoff properties measured were time to runoff and initial abstraction (infiltration), total runoff depth and average runoff rates, as well as concentrations and mass loads of sediment, N, and P fractions. Cattle trails significantly ( ≤ 0.10) decreased time to runoff and initial abstraction (26-32%) in the 2 yr measured and increased total runoff depth, runoff coefficients, and average runoff rates (21-51%) in 2 of 3 yr. Concentrations of sediment, N, and P fractions in runoff were not significantly greater for cattle trails than for control areas. However, mass loads of total suspended solids (57-85% increase), NH-N (31-90%), and dissolved reactive P (DRP) (30-92%) were significantly greater because of increased runoff volumes. Overall, runoff quantity and loads of sediment, NH-N, and DRP were greater for cattle trails compared with the adjacent grazed pasture, and hydrologic connection with cattle-access sites on the riverbank suggests that this could adversely affect water quality in the adjacent river. Extrapolation of the study results should be tempered by the specific conditions represented by this rainfall simulation study. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  10. Run-off from roofing materials

    International Nuclear Information System (INIS)

    Roed, J.

    1985-01-01

    In order to find the runn-off from roof material, a roof has been constructed with two different slopes (30 deg. and 45 deg.). 7 Be and 137 Cs have been used as tracers. Considering new roof material, the pollution removed by run-off processes has been shown to be very different for various roof materials. The pollution is much more easily removed from silicon-treated material than from porous red-tile roof material. Cesium is removed more easily than beryllium. The content of cesium in old roof materials is greater in red-tile than in other less porous roof materials. However, the measured removal from new material does not correspond to the amount accumulated in the old. This could be explained by weathering and by saturation effects. The last effect is probably the more important. The measurements on old material indicate a removal of 44-86% of cesium pollution by run-off, whereas the measurement on new material showed a removal of only 31-50%. It has been demonstrated that the pollution concentration in run-off water could be very different from that in rainwater

  11. Interactive effects of combined inorganic and organic fertilizers on phosphorous adsorption, desorption and mobility

    International Nuclear Information System (INIS)

    Li Xiang; Liu Yanxia; Liu Yiren; Xu Yangchun

    2013-01-01

    A "3"2P-labeled experiment was conducted to investigate the mechanisms of combining inorganic and organic fertilizers affecting P availability. Results showed that the characters of soil P adsorption-desorption changed remarkably with different patterns of fertilizer application. The affinity constant (k) of soil P adsorption, the maximal P adsorption (Q) and the buffering capacity of P adsorption (MBC) of the treatment of 80/20 were lower than those of the 100/0 treatment. The thin-layer chromatography (TLC) showed that "3"2P of the 80/20 treatment moved faster than the 100/0 treatment. The leaching volumes collected for each treatment when "3"2P first was observed were 13.1 mL for the treatment 80 : 20, 19.0 mL for the treatment of 100 : 0 and 19.8 mL (0 : 0) mL. Total "3"2P recovery for the 100 : 0 and the 80 : 20 treatments increased significantly after nearly 45 mL of leachates were collected. When the leachates reached 50 mL, only 1.6%, 8.4% and 9.8% of the applied "3"2P leached out from the 0 : 0, 100 : 0 and 80 : 20 treated soils, respectively. The findings indicated that combined organic and inorganic fertilizers could suppress the decreasing of P fixation, enhance P mobility more effectively and improve P use efficiency. (authors)

  12. Nitrogen Deposition and Leaching from Two Forested Catchments in Southwest China — Preliminary Data and Research Needs

    Directory of Open Access Journals (Sweden)

    T. Larssen

    2001-01-01

    Full Text Available Increased nitrogen deposition has resulted in increased nitrogen pools and nitrogen leaching in European and North American forest soils. The development in Asia in general, and China in particular, suggests increased deposition of reduced nitrogen from changes in agricultural practices and of oxidized nitrogen from rapid growth of the transportation sector. Decreased nitrogen retention in forested areas in the future may cause increased NO3– leaching and, thus, acidification and eutrophication in surface waters. The differences in climate, ecosystems, land use, and deposition history make direct application of knowledge from studies in Europe and North America difficult. In Southwest China the potential for nitrogen mobilization from forest soils may be high because of the warm and humid climate, resulting in high decomposition rates of soil organic matter. However, there are very few data available for quantifying the suspected potential for increased nitrogen leaching in forest ecosystems. Here we present data from two forested catchments, dominated by Masson pine (Pinus massoniana, near Guiyang and Chongqing, respectively, in Southwest China. The present nitrogen deposition is moderate, estimated in the range from 10 to 40 kg N ha–1 year–1. The C/N ratios of the soils are generally below 15. Nitrate concentrations in soil water are rather variable in space, with highest values of several hundred microequivalents per liter. The turnover rate of nitrogen in the forest ecosystem is quite high compared to the atmospheric deposition rate. At present, nitrate runoff from the catchments is low and intermediate in Guiyang and Chongqing, respectively. More research is needed to improve our ability to predict future nitrogen leaching from subtropical Asian coniferous forests.

  13. Comparison of leach results from field and laboratory prepared samples

    International Nuclear Information System (INIS)

    Oblath, S.B.; Langton, C.A.

    1985-01-01

    The leach behavior of saltstone prepared in the laboratory agrees well with that from samples mixed in the field using the Littleford mixer. Leach rates of nitrates and cesium from the current reference formulation saltstone were compared. The laboratory samples were prepared using simulated salt solution; those in the field used Tank 50 decontaminated supernate. For both nitrate and cesium, the field and laboratory samples showed nearly identical leach rates for the first 30 to 50 days. For the remaining period of the test, the field samples showed higher leach rates with the maximum difference being less than a factor of three. Ruthenium and antimony were present in the Tank 50 supernate in known amounts. Antimony-125 was observed in the leachate and a fractional leach rate was calculated to be at least a factor of ten less than that of 137 Cs. No 106 Ru was observed in the leachate, and the release rate was not calculated. However, based on the detection limits for the analysis, the ruthenium leach rate must also be at least a factor of ten less than cesium. These data are the first measurements of the leach rates of Ru and Sb from saltstone. The nitrate leach rates for these samples were 5 x 10 -5 grams of nitrate per square cm per day after 100 days for the laboratory samples and after 200 days for the field samples. These values are consistent with the previously measured leach rates for reference formulation saltstone. The relative standard deviation in the leach rate is about 15% for the field samples, which all were produced from one batch of saltstone, and about 35% for the laboratory samples, which came from different batches. These are the first recorded estimates of the error in leach rates for saltstone

  14. Impact of carbonaceous materials in soil on the transport of soil-bound PAHs during rainfall-runoff events.

    Science.gov (United States)

    Luo, Xiaolin; Zheng, Yi; Wu, Bin; Lin, Zhongrong; Han, Feng; Zhang, Wei; Wang, Xuejun

    2013-11-01

    Polycyclic Aromatic Hydrocarbons (PAHs) transported from contaminated soils by surface runoff pose significant risk for aquatic ecosystems. Based on a rainfall-runoff simulation experiment, this study investigated the impact of carbonaceous materials (CMs) in soil, identified by organic petrology analysis, on the transport of soil-bound PAHs under rainfall conditions. The hypothesis that composition of soil organic matter significantly impacts the enrichment and transport of PAHs was proved. CMs in soil, varying significantly in content, mobility and adsorption capacity, act differently on the transport of PAHs. Anthropogenic CMs like black carbon (BC) largely control the transport, as PAHs may be preferentially attached to them. Eventually, this study led to a rethink of the traditional enrichment theory. An important implication is that CMs in soil have to be explicitly considered to appropriately model the nonpoint source pollution of PAHs (possibly other hydrophobic chemicals as well) and assess its environmental risk. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Traps for phosphorus adsorption

    International Nuclear Information System (INIS)

    Montoya, Nawer D; Villegas, Wilson E; Rodriguez, Lino M; Taborda, Nelson; Montes de C, Consuelo

    2001-01-01

    Several AL 2 O 3 supported oxides such as: NiO, CuO, Co 2 O 3 BaO, CeO 2 and ZnO were investigated for phosphorus adsorption. Zno/y-Al 2 O 3 exhibited the highest phosphorus adsorption capacity. However, since it diminishes the activity of to the reaction mixture it should be located upstream of the NoX catalyst, i.e. 0,3% Pd-H-MOR, in order to protect it against p poisoning. The treatment procedure with citric acid was effective for the removal of more than 70% phosphorus from the adsorbent, ZnO/y-Al 2 O 3

  16. Quality of urban runoff in wet and dry seasons: a case study in a semi-arid zone.

    Science.gov (United States)

    Ortiz-Hernández, Joyce; Lucho-Constantino, Carlos; Lizárraga-Mendiola, Liliana; Beltrán-Hernández, Rosa Icela; Coronel-Olivares, Claudia; Vázquez-Rodríguez, Gabriela

    2016-12-01

    Urban runoff (UR) is a promising new resource that may alleviate growing tensions in numerous arid and semi-arid regions of the world. However, it is precisely in these zones that the available UR quality characteristics are scarcer. This work aims to evaluate a wide set of parameters to establish a detailed approach to both the quality of UR in a midsized city in Central Mexico and the feasibility of using UR to recharge aquifers. UR from an institutional land use site was sampled during wet and dry seasons and assessed for suspended solids, organic matter, nutrients, microorganisms, metals, and persistent organic chemicals (i.e., polycyclic aromatic hydrocarbons, PAH). The results were analyzed using multivariate statistical methods to identify relationships among the variables, the sampling sites and the seasons. The soil erosion and the leaching of materials due to the water flow through vegetated areas were identified as the most influencing factor on the quality of the site runoff in both dry and wet seasons. Additionally, data were more heterogeneous during the dry season, and higher pollutant concentrations were found both during the dry season and in more pervious zones. We consider UR a promising water source for recharging aquifers in arid and semi-arid zones if a program is implemented that can integrate an adequate runoff treatment system, soil protection, and other non-structural measures.

  17. Design and Development of Low P-Emission Substrate for the Protection of Urban Water Bodies Collecting Green Roof Runoff

    Directory of Open Access Journals (Sweden)

    Agnieszka Karczmarczyk

    2017-10-01

    Full Text Available Urbanization leads to higher phosphorus (P concentration in urban catchments. Among different stormwater retention measures, green roofs are the least efficient in phosphorus retention. Moreover, much research has shown that green roofs act as sources of phosphorus, and they can emit P in significant loads. In this study low P emission green roof substrate was developed based on the proposed step by step procedure for the selection of materials including laboratory tests, column experiments, and the monitoring of the open air green roof model. Developed substrate is the mixture of crushed red brick (35% of volume, crushed limestone (20% of volume, and sand (45% of volume, and is characterized by a bulk density of 1.52 g/cm3, water permeability of 9 mm/min, water capacity of 24.6% of volume, and granulometric composition that meets the Landscaping and Landscape Development Research Society (FLL guidelines. Limestone was added to limit the potential P leaching from crushed red brick and vegetated mate consisted of Sedum album, Sedum acre, Sedum kamtschaticum, Sedum spurium, Sedum reflexum, Sedum sexangulare, Dianthus deltoides, Dianthus carthusianorum, and Thymus vulgaris. The open air model experiment was run for 319 days, from March 2015 to February 2016. The total water runoff from the green roof model amounted to 43.3% of runoff from the reference roof. The only one runoff event polluted with phosphorus was connected with the outflow of melted snow from an unfreezing green roof model.

  18. Diffusion Influenced Adsorption Kinetics.

    Science.gov (United States)

    Miura, Toshiaki; Seki, Kazuhiko

    2015-08-27

    When the kinetics of adsorption is influenced by the diffusive flow of solutes, the solute concentration at the surface is influenced by the surface coverage of solutes, which is given by the Langmuir-Hinshelwood adsorption equation. The diffusion equation with the boundary condition given by the Langmuir-Hinshelwood adsorption equation leads to the nonlinear integro-differential equation for the surface coverage. In this paper, we solved the nonlinear integro-differential equation using the Grünwald-Letnikov formula developed to solve fractional kinetics. Guided by the numerical results, analytical expressions for the upper and lower bounds of the exact numerical results were obtained. The upper and lower bounds were close to the exact numerical results in the diffusion- and reaction-controlled limits, respectively. We examined the validity of the two simple analytical expressions obtained in the diffusion-controlled limit. The results were generalized to include the effect of dispersive diffusion. We also investigated the effect of molecular rearrangement of anisotropic molecules on surface coverage.

  19. LEACHING AND DEGRADATION OF 2,4-DICHLOROPHENOXIACETIC ACID, IN COLOMBIA RICE FLOODED SOIL.

    Science.gov (United States)

    Huertas, J; Guerrero, J A; Martinez-Cordon, M J

    2015-01-01

    Rice is mostly cultivated on soil held under flooded conditions. Under these conditions pesticides undergo reductive transformations which are characteristic to rice fields and other anaerobic systems. The present study was undertaken to evaluate the mobility and persistence of 2,4-dichlorophenoxy acetic acid (2,4-D) under laboratory conditions for the rice crop in Espinal, Colombia. A displacement study was performed on a hand packed soil column 30 cm length. After leaching experiment, the soil from column was sliced into six successive sections (5 cm). Methanol acidified (H3PO4 0.25%) extraction was used to determine the herbicide residues in each section. 2,4-D experimental breakthrough curve was analyzed using Stanmod program (inverse problem) to obtain transport parameters. The non-equilibrium physical model fitted well the experimental breakthrough curve. The recovery percent of 2,4-D in leachates was 36.44% after 3.4 pore volumes, and retardation factor was 2.1, indicating low adsorption in that conditions. 2,4-D was rapidly degraded, with DT50 = 11.4 days. The results suggest that 2,4-D under flooded conditions have a high potential for leaching through the soil profile, although the elevated rate of degradation reduced the ground water contamination risk.

  20. Removal of I by adsorption with AgX (Ag-impregnated X Zeolite) from high-radioactive seawater waste

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eil Hee; Lee, Keun Young; Kim, Kwang Wook; Kim, Hyung Ju; Kim, Ik Soo; Chung, Dong Yong; Moon, Jei Kwon; Choi, Jong Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-09-15

    This study aimed to the adsorption-removal of high- radioactive iodide (I) contained in the initially generated high-radioactive seawater waste (HSW), with the use of AgX (Ag-impregnated X zeolite). Adsorption of I by AgX (hereafter denoted as AgX-I adsorption) was increased by increasing the Ag-impregnated concentration in AgX, and its concentration was suitable at about 30 wt%. Because of AgCl precipitation by chloride ions contained in seawater waste, the leaching yields of Ag from AgX (Ag-impregnated concentration : about 30-35 wt%) was less than those in distilled water (< 1 mg/L). AgX-I adsorption was above 99% in the initial iodide concentration (Ci) of 0.01-10 mg/L at m/V (ratio of weight of adsorbent to solution volume)=2.5 g/L. This shows that efficient removal of I is possible. AgX-I adsorption was found to be more effective in distilled water than in seawater waste, and the influence of solution temperature was insignificant. Ag-I adsorption was better described by a Freundlich isotherm rather than a Langmuir isotherm. AgX-I adsorption kinetics can be expressed by a pseudo-second order rate equation. The adsorption rate constants (k2) decreased by increasing Ci, and conversely increased by increasing the ratio of m/V and the solution temperature. This time, the activation energy of AgX-I adsorption was about 6.3 kJ/mol. This suggests that AgX-I adsorption is dominated by physical adsorption with weaker bonds. The evaluation of thermodynamic parameters (a negative Gibbs free energy and a positive Enthalpy) indicates that AgX-I adsorption is a spontaneous reaction (forward reaction), and an endothermic reaction indicating that higher temperatures are favored.

  1. Accelerated Leach Test(s) Program: Annual report

    International Nuclear Information System (INIS)

    Dougherty, D.R.; Pietrzak, R.F.; Fuhrmann, M.; Colombo, P.

    1986-09-01

    A computerized data base of LLW leaching data has been developed. Long-term tests on portland cement, bitumen and vinyl ester-styrene (VES) polymer waste forms containing simulated wastes are underway which are designed to identify and evaluate factors that accelerate leaching without changing the mechanisms

  2. Nitrate leaching and pesticide use in energy crops

    DEFF Research Database (Denmark)

    Jørgensen, Uffe

    2006-01-01

    Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well.......Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well....

  3. LEACHING BOUNDARY IN CEMENT-BASED WASTE FORMS

    Science.gov (United States)

    Cement-based fixation systems are among the most commonly employed stabilization/solidification techniques. These cement haste mixtures, however, are vulnerable to ardic leaching solutions. Leaching of cement-based waste forms in acetic acid solutions with different acidic streng...

  4. Package characterization by laboratory leaching and diffusion experiments using radionuclides

    International Nuclear Information System (INIS)

    Das, H.A.

    1989-01-01

    The leaching of solid inorganic waste from loaded concrete or cement by incoming water can be described in terms of a steady-state outward diffusion of the saturated solution, formed inside the pores. In this paper, the derived equations permit the prediction of long-term leaching behavior. Radiotracer experiments enable the determination of the parameters involved

  5. Developments of uranium and gold ores heap leaching technologies

    International Nuclear Information System (INIS)

    Tian Yuan; Guan Zibin; Gao Renxi

    1998-01-01

    The author reviews developments in heap leaching of uranium and gold ores at home and abroad, summarises condition of application. The author also presents problems having to be studied and settled urgently in heap leaching of uranium and gold ores in China

  6. Leaching of RA-226 contaminated gravel using different aqueous treatments

    Energy Technology Data Exchange (ETDEWEB)

    Mamoon, A; Abulfaraj, W H; Sohsah, M A [King Abdulaziz University, Jeddah, Saudi Arbabia (Saudi Arabia)

    1997-12-31

    Investigation of the efficiencies of different aqueous leaching treatments was carried out on gravel artificially contaminated with Ra-226. The extent of leaching efficiency was determined in terms of Ra-226 and its daughter Rn-222. Liquid scintillation counting using high efficiency mineral oil based liquid scintillator was the technique adopted for measuring Ra-226 and Rn-222 leached off the contaminated gravel. Water, dilute solutions of barium chloride and HCl were used as leachants. Different masses of gravel were leached with 200 mL of leachant for various contact time periods. The leached Rn-222 activity measured was plotted vs the decay factor e; from which Rn-222 and Ra-226 originally present in the sample were determined. Several leaching parameters were tested; namely type of leachant, leachant volume/gravel mass ratio, leachant contact time, effect of varying Ba Cl{sub 2} concentration, and successive leaching. Optimization of the leaching parameters for desorption of Ra-226 off the contaminated gravel under laboratory conditions may help determine the ideal conditions for remediating soil contaminated with radium or chemically similar radionuclides. 7 figs.

  7. An experimental study on gold precipitation from leach solutions of ...

    African Journals Online (AJOL)

    This paper presents the results of the study dedicated to the determination of the optimum parameters for the electrolytic gold precipitation from thiourea leach solutions. The leaching was carried out using technogenic gold-bearing raw materials (gold-bearing sands) of the Far East of the Russian Federation. The study ...

  8. Static leaching of uraniferous shales on open areas

    International Nuclear Information System (INIS)

    Hernandez Nieto, J.; Cordero, G.; Villarrubia, M.

    1973-01-01

    This report describes the tests on acid heap leaching with conventional (1.400 ppm U 3 O 8 ) crushed uranium ores. We use open circuits with low internal recycled. Using starving acidity in the leaching solutions we obtain a smooth solubilization of uranium and, at the same time, the pregnant liquors are good for the solvent extraction recovery. (Author)

  9. Aqueous-chlorine leaching of typical Canadian uranium ores

    International Nuclear Information System (INIS)

    Haque, K.E.

    1982-01-01

    Laboratory-scale aqueous-chlorine leaches were conducted on quartz-pebble conglomerates, pegmatite and vein-type ores. Optimum leach temperatures, pulp density and retention times were determined. Uranium extraction of 98 per cent was obtained from the Elliot Lake, Madawaska Mines of Bancroft and Rabbit Lake ores, 96 per cent from the Key Lake ore and 86 per cent from the Agnew Lake ore. However, tailings containing 15-20 pCi g -1 of radium-226 were obtained only from the Elliot Lake and Agnew lake quartz-pebble conglomerates and Bancroft pegmatite-type ores by second-stage leaches with HCl. The second-stage leach results indicate that multistage (3 or 4) acid-chloride or salt-chloride leaches might be effective to obtain tailings containing 15-20 pCi 226 Ra g -1 from the high-grade vein-type ores. Comparative reagent-cost estimates show that the sulphuric-acid leach process is far less expensive than aqueous chlorine leaching. Nevertheless, only the aqueous chlorine and acid-chloride leaches in stages are effective in producing tailings containing 15-20 pCi 226 Ra g -1 from the typical Canadian uranium ores. (Auth.)

  10. Manual of acid in situ leach uranium mining technology

    International Nuclear Information System (INIS)

    2001-08-01

    In situ leaching (ISL) technology recovers uranium using two alternative chemical leaching systems - acid and alkaline. This report brings together information from several technical disciplines that are an essential part of ISL technology. They include uranium geology, geohydrology, chemistry as well as reservoir engineering and process engineering. This report provides an extensive description of acid ISL uranium mining technology

  11. Manual of acid in situ leach uranium mining technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-08-01

    In situ leaching (ISL) technology recovers uranium using two alternative chemical leaching systems - acid and alkaline. This report brings together information from several technical disciplines that are an essential part of ISL technology. They include uranium geology, geohydrology, chemistry as well as reservoir engineering and process engineering. This report provides an extensive description of acid ISL uranium mining technology.

  12. Scheduling of Irrigation and Leaching Requirements

    Directory of Open Access Journals (Sweden)

    Amer Hassan Al-haddad

    2015-03-01

    Full Text Available Iraq depends mainly on Tigris and Euphrates Rivers to provide high percentage of agricultural water use for thousands years. At last years, Iraq is suffering from shortage in water resources due to global climate changes and unfair water politics of the neighboring countries, which affected the future of agriculture plans for irrigation, added to that the lack of developed systems of water management in the irrigation projects and improper allocation of irrigation water, which reduces water use efficiency and lead to losing irrigation water and decreasing in agricultural yield. This study aims at studying the usability of irrigation and leaching scheduling within the irrigating projects and putting a complete annual or seasonal irrigation program as a solution for the scarcity of irrigation water, the increase of irrigation efficiency, lessening the salinity in the projects and preparing an integral irrigation calendar through field measurements of soil physical properties and chemical for project selected and compared to the results of the irrigation scheduling and leaching with what is proposed by the designers. The process is accomplished by using a computer program which was designed by Water Resources Department at the University of Baghdad, with some modification to generalize it and made it applicable to various climatic zone and different soil types. Study area represented by large project located at the Tigris River, and this project was (Al-Amara irrigation project. Sufficient samples of project's soil were collected so as to identify soil physical and chemical properties and the salinity of soil and water as well as identifying the agrarian cycles virtually applied to this project. Finally, a comparison was conducted between the calculated water quantities and the suggested ones by the designers. The research results showed that using this kind of scheduling (previously prepared irrigation and leaching scheduling with its properties

  13. Propagation of soil moisture memory to runoff and evapotranspiration

    Science.gov (United States)

    Orth, R.; Seneviratne, S. I.

    2012-10-01

    As a key variable of the land-climate system soil moisture is a main driver of runoff and evapotranspiration under certain conditions. Soil moisture furthermore exhibits outstanding memory (persistence) characteristics. Also for runoff many studies report distinct low frequency variations that represent a memory. Using data from over 100 near-natural catchments located across Europe we investigate in this study the connection between soil moisture memory and the respective memory of runoff and evapotranspiration on different time scales. For this purpose we use a simple water balance model in which dependencies of runoff (normalized by precipitation) and evapotranspiration (normalized by radiation) on soil moisture are fitted using runoff observations. The model therefore allows to compute memory of soil moisture, runoff and evapotranspiration on catchment scale. We find considerable memory in soil moisture and runoff in many parts of the continent, and evapotranspiration also displays some memory on a monthly time scale in some catchments. We show that the memory of runoff and evapotranspiration jointly depend on soil moisture memory and on the strength of the coupling of runoff and evapotranspiration to soil moisture. Furthermore we find that the coupling strengths of runoff and evapotranspiration to soil moisture depend on the shape of the fitted dependencies and on the variance of the meteorological forcing. To better interpret the magnitude of the respective memories across Europe we finally provide a new perspective on hydrological memory by relating it to the mean duration required to recover from anomalies exceeding a certain threshold.

  14. [Adsorptive Stabilization of Soil Cr (VI) Using HDTMA Modified Montmorillonite].

    Science.gov (United States)

    2016-03-15

    A series of organo-montomorillonites were prepared using Na-montomorillonite and hexadecyl trimethyl ammonium bromide (HDTMA). The organo-montomorillonites were then investigated for the remediation of Cr(VI) contaminated soils. FT-IR, XRD, SEM and N2 -BET, CEC, Zeta potential measurement were conducted to understand the structural changes of montmorillonites as different amounts of HDTMAs were added as modifier. The characterization results indicated that the clay interlayer spacing distance increased from 1. 25 nm to 2. 13 nm, the clay surface roughness decreased, the clay surface area reduced from 38.91 m² · g⁻¹ to 0.42 m² · g⁻¹, the clay exchangeable cation amount reduced from 62 cmol · kg⁻¹ to 9.9 cmol · kg⁻¹ and the clay surface charge changed from -29.1 mV to 5.59 mV as the dosage of HDTMA in montmorillonite was increased. The TCLP (toxicity characteristic leaching procedure) was used to evaluate the leachate toxicity of Cr(VI). The effects of the initial soil Cr(VI) concentration, montmorillonites dosage, reaction time and HDTMA modification amount were investigated, respectively. The results revealed that modification of montmorillonites would manifest an attenuated physical adsorptive effect and an enhanced electrostatic adsorptive effect on Cr(VI), suggesting electrostatic effect was the major force that resulted in improved Cr(VI) adsorption onto HDTMA modified montmorillonites.

  15. Hydrochloric acid leach of Agnew Lake uranium concentrate

    International Nuclear Information System (INIS)

    Haque, K.E.; Ipekoglue, B.

    1981-10-01

    Hydrochloric acid leaching was conducted on the radioactive mineral concentrate separated from the Agenw Lake uranium ore. Leach tests conducted at the optimum conditions (75 0 C; 36 hours; 66.0 Kg HCl/tonne; solid:liquid -1:1) resulted in the extraction of 87% uranium and 84% radium. The radionuclide level of the residue was U-0.016%, Th-0.24% and Ra-65 pCi/g solids. However to obtain a residue almost free of radium (i.e., Ra level at the detection limit: 4-6 pCi/g solids), the first stage leach residue was further treated with hydrochloric acid. The radium level in the best second stage leach residue was also above the target level. Therefore, multistage (3 or 4) hydrochloric acid and/or neutral chloride leaching is recommended to obtain tailings almost free of radionuclide

  16. COMPILATION OF LABORATORY SCALE ALUMINUM WASH AND LEACH REPORT RESULTS

    International Nuclear Information System (INIS)

    Harrington, S.J.

    2011-01-01

    This report compiles and analyzes all known wash and caustic leach laboratory studies. As further data is produced, this report will be updated. Included are aluminum mineralogical analysis results as well as a summation of the wash and leach procedures and results. Of the 177 underground storage tanks at Hanford, information was only available for five individual double-shell tanks, forty-one individual single-shell tanks (e.g. thirty-nine 100 series and two 200 series tanks), and twelve grouped tank wastes. Seven of the individual single-shell tank studies provided data for the percent of aluminum removal as a function of time for various caustic concentrations and leaching temperatures. It was determined that in most cases increased leaching temperature, caustic concentration, and leaching time leads to increased dissolution of leachable aluminum solids.

  17. Remediation of hazardous waste sites by heap leaching

    International Nuclear Information System (INIS)

    Samani, Z.; Hanson, A.; Dwyer, B.

    1994-01-01

    Efforts are being made to devise technologies and treatment systems to remediate contaminated soil-on site without generating significant wastes for off-site disposal. Heap leaching, a technique used extensively in the mining industry, has been investigated as a method for remediation of hazardous chemical contamination of the vadose zone. In the mining industry, metal-bearing ore is excavated and mounded on a pad. The metals are removed by passing a special leaching solution through the ore. In this study, the removal of chromium(VI) from the New Mexico soils (sand, sandy loam, and clay) using heap leaching was evaluated at a column scale. The heap leaching study demonstrated greater than 99% removal of Cr(VI) from all three soils using tap water as the leaching agent. (author) 13 figs., 5 tabs., 21 refs

  18. COMPILATION OF LABORATORY SCALE ALUMINUM WASH AND LEACH REPORT RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    HARRINGTON SJ

    2011-01-06

    This report compiles and analyzes all known wash and caustic leach laboratory studies. As further data is produced, this report will be updated. Included are aluminum mineralogical analysis results as well as a summation of the wash and leach procedures and results. Of the 177 underground storage tanks at Hanford, information was only available for five individual double-shell tanks, forty-one individual single-shell tanks (e.g. thirty-nine 100 series and two 200 series tanks), and twelve grouped tank wastes. Seven of the individual single-shell tank studies provided data for the percent of aluminum removal as a function of time for various caustic concentrations and leaching temperatures. It was determined that in most cases increased leaching temperature, caustic concentration, and leaching time leads to increased dissolution of leachable aluminum solids.

  19. A field study to evaluate the impact of different factors on the nutrient pollutant concentrations in green roof runoff.

    Science.gov (United States)

    Wang, Xiaochen; Zhao, Xinhua; Peng, Chenrui; Zhang, Xinbo; Wang, Jianghai

    2013-01-01

    The objectives of this study are to investigate the impact of different factors on the nutrient pollutant concentrations in green roof runoff and to provide reference data for the engineering design of dual substrate layer green roofs. The data were collected from eight different trays under three kinds of artificial rains. The results showed that except for total phosphorus, dual substrate layer green roofs behaved as a sink for most of the nutrient pollutants (significant at p green roof and the depth of the adsorption substrates. Compared with the influence of the substrates, the influence of the plant density and drainage systems was small.

  20. Radiocesium leaching from contaminated litter in forest streams

    International Nuclear Information System (INIS)

    Sakai, Masaru; Gomi, Takashi; Naito, Risa S.; Negishi, Junjiro N.; Sasaki, Michiko; Toda, Hiroto; Nunokawa, Masanori; Murase, Kaori

    2015-01-01

    In Japanese forests suffering from the Fukushima Daiichi Nuclear Power Plant accident, litter fall provides a large amount of radiocesium from forests to streams. Submerged litter is processed to become a vital food resource for various stream organisms through initial leaching and subsequent decomposition. Although leaching from litter can detach radiocesium similarly to potassium, radiocesium leaching and its migration are poorly understood. We examined both radiocesium and potassium leaching to the water column and radiocesium allocation to minerals (glass beads, silica sand, and vermiculite) in the laboratory using soaked litter with and without minerals on a water column. The mineral types did not affect radiocesium leaching from litter, but soaking in water for 1, 7, and 30 days decreased the radiocesium concentration in litter by ×0.71, ×0.66, and ×0.56, respectively. Meanwhile, the 1-, 7-, and 30-day experiments decreased potassium concentration in litter by ×0.17, ×0.11, and ×0.09, respectively. Leached radiocesium remained in a dissolved form when there was no mineral phases present in the water, whereas there was sorption onto the minerals when they were present. In particular, vermiculite adsorbed radiocesium by two to three orders of magnitude more effectively than the other minerals. Because radiocesium forms (such as that dissolved or adsorbed to organic matter or minerals) can further mobilize to ecosystems, our findings will increase our understanding regarding the dynamics of radiocesium in stream ecosystems. - Highlights: • Radiocesium in contaminated litter was leached when soaked in water. • Radiocesium in litter leached slowly compared to potassium. • Minerals adsorbed dissolved radiocesium that was leached from litter. • Vermiculite effectively adsorbed radiocesium leached from litter

  1. SULPHUR DIOXIDE LEACHING OF URANIUM CONTAINING MATERIAL

    Science.gov (United States)

    Thunaes, A.; Rabbits, F.T.; Hester, K.D.; Smith, H.W.

    1958-12-01

    A process is described for extracting uranlum from uranium containing material, such as a low grade pitchblende ore, or mill taillngs, where at least part of the uraniunn is in the +4 oxidation state. After comminuting and magnetically removing any entrained lron particles the general material is made up as an aqueous slurry containing added ferric and manganese salts and treated with sulfur dioxide and aeration to an extent sufficient to form a proportion of oxysulfur acids to give a pH of about 1 to 2 but insufficient to cause excessive removal of the sulfur dioxide gas. After separating from the solids, the leach solution is adjusted to a pH of about 1.25, then treated with metallic iron in the presence of a precipitant such as a soluble phosphate, arsonate, or fluoride.

  2. Leach characterization of cement encapsulated wastes

    International Nuclear Information System (INIS)

    Roy, D.M.; Scheetz, B.E.; Wakeley, L.D.; Barnes, M.W.

    1982-01-01

    Matrix encapsulation of defense nuclear waste as well as intermediate-level commercial wastes within a low-temperature cementitious composite were investigated. The cements for this study included both as-received and modified calcium silicate and calcium aluminate cements. Specimens were prepared following conventional formulation techniques designed to produce dense monoliths, followed by curing at 60 0 C. An alternative preparation procedure is contrasted in which the specimens were ''warm'' pressed in a uniaxial press at 150 0 C at 50,000 psi for 0.5 h. Specimens of the waste/cement composites were leached in deionized water following three different procedures which span a wide range of temperatures and solution saturation conditions. Aluminate and compositionally adjusted silicate cements exhibited a better retentivity for Cs and Sr than did the as-received silicate cement. 15 refs

  3. Building a Uranium Heap Leach Project

    International Nuclear Information System (INIS)

    Schnell, Henry

    2014-01-01

    Despite all these we have seen many HL successes and many interesting projects coming down the pipe. • Previous experience in Uranium with previous ROM projects in France (Bessines, Langone), Niger (Somair), Canada (Agnew Lake) and other locations had provided some basic background. • Heap leach based on copper experience with crushed ore has operated for many years in Brazil (Caetite). • Many gold operations for many decades in all climates and continents. • Copper at +20% of production, many in Chile, but also now in many other countries. • Uranium with agglomerated crushed ores is now becoming more prominent – Somair, Imouraren, Trekkopje. • Work also ongoing for Ranger, Rossing, and in consideration for other projects. • Other notable work in Nickel, and multi-metal such as Talvivaara

  4. Groundwater remediation in the Straz leaching operation

    International Nuclear Information System (INIS)

    Novak, J.

    2001-01-01

    The locality affected by consequences of the chemical mining of the uranium during underground leaching 'in situ' is found in the area of the Czech Republic in the northeastern part of the Ceska Lipa district. In the contribution the complex groundwater remediation project is discussed. First, the risks of the current state are expressed. Then the alternatives of remediation of the both Cenomanian and Turonian aquifers are presented. Evaluation of the remediation alternatives with the view to the time-consumption, economy, ecology and the elimination of unacceptable risks for the population and environment is done. Finally, the present progress of remediation and the conception of remediation of chemical mining on deposit of Straz pod Ralskem are presented. (orig.)

  5. Pesticide leaching in a changing climate

    DEFF Research Database (Denmark)

    Rasmussen, Signe Bonde

    There is a widespread consensus among scientists that the climate will change in the future, and that this change has already begun. These climatic changes will undoubtedly challenge the use of pesticides, which has been proposed to increase in the future. Accordingly, the primary aim of this Ph......D-project was to contribute to the knowledge of how climate change will effect pesticide leaching in the future, which was done by use of mathematical modelling. The agro-ecological model Daisy, was used in all simulations, as well as the 2 model soils: a coarse sand and a subsurface drained sandy loam containing......, resulting in 3000-year long weather series of statistically stationary climate. Effects of pesticide properties (sorption and degradation), pesticide application dates, and soil properties were included. The synthetic weather series produced in relation to objective (II) were used to simulate future changes...

  6. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Butera, Stefania; Kosson, D.S.

    2015-01-01

    of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens......Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis......, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system...

  7. Copper adsorption in tropical oxisols

    Directory of Open Access Journals (Sweden)

    Silveira Maria Lucia Azevedo

    2003-01-01

    Full Text Available Cu adsorption, at concentrations between 0 to 800 mg L-1, was evaluated in surface and subsurface samples of three Brazilian soils: a heavy clayey-textured Rhodic Hapludalf (RH, a heavy clayey-textured Anionic ''Rhodic'' Acrudox (RA and a medium-textured Anionic ''Xanthic'' Acrudox (XA. After adsorption, two consecutive extractions were performed to the samples which received 100 mg L-1 copper. Surface samples adsorbed higher amounts of Cu than the subsurface, and exhibited lower Cu removed after the extractions, reinforcing the influence of the organic matter in the reactions. Cu adsorption was significant in the subsurface horizons of the Oxisols, despite the positive balance of charge, demonstrating the existence of mechanisms for specific adsorption, mainly related to the predominance of iron and aluminum oxides in the mineral fractions. In these samples, Cu was easily removed from the adsorption sites. RH demonstrated a higher capacity for the Cu adsorption in both horizons.

  8. Experimental leaching of uranium from tuffaceous rocks

    International Nuclear Information System (INIS)

    Goodell, P.C.; Trentham, R.C.

    1980-07-01

    The premise to be tested in this work is that felsic volcanic rocks particularly ash-flow tuffs, can serve as source rocks for certain uranium deposits. The applicability of this idea to several geologic environments is investigated. A genetic model is developed dealing with the behavior of uranium during and subsequent to ash-flow tuff deposition. It is based upon previously described investigations, geologic logic, data presented here, and speculation. Ash-flow tuff sequences described in the literature show significant alkali element variation, particularly in thick tuff units. Some variation is attributed to initial magma variations, whereas additional change may be produced during cooling and degassing of the tuff. Uranium variations have been documented in tuff sequences which are assumed to represent magmatic compositions. Uranium may be released during the initial degassing, during hydrothermal alteration, and/or during later diagenesis. Experimental studies have been designed and carried out to simulate natural leaching conditions such as might occur during diagenesis. Synthetic ground waters have been pumped through pulverized uraniferous vitrophyres. Major and minor element contents have been determined. The most significant chemical changes take place quickly, within a matter of days. Several starting and product leachant solutions were analyzed fluorimetrically for uranium. They show significant increases in uranium contents, from less than 1 ppB at the start to greater than 10 ppB maximu. Such leachant solutions might be significant transport agents of uranium given geologic time. Leaching at low temperatures appears to involve a thin surface reaction and diffusion layer. Both dissolution and ion exchange influence the leachant composition. It is also concluded that glassy ash-flow tuffs may serve as uranium source rocks during low temperature diagenetic changes

  9. The performance with data processing of chemical treatment with leaching and bio-leaching

    OpenAIRE

    Agron, Alili; Krstev, Boris; Krstev, Aleksandar; Stamenov, Goran

    2015-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and excel...

  10. The performance of leaching and bio-leaching from sulphide ores usiing SEVOP

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Golomeov, Blagoj; Golomeova, Mirjana; Sala, Ferat; Gocev, Zivko; Zivanovic, Jordan; Krstev, Dejan

    2013-01-01

    The refractory or low grade copper chalcopyrite ores or galena/sphalerite domestic ores in Republic of Macedonia are investigated by conventional copper flotation and selective flotation for galena/sphalerite. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer programme. Multisimple...

  11. The principles and examples of leaching and bio-leaching using SImplex EVOP

    OpenAIRE

    Krstev, Aleksandar; Krstev, Boris

    2014-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms - bioleaching. The paper is result of these technologies and investigations earned out for recovery of in the mentioned ores. Using Simples EVOP and computer program Multisimplex performances are appropriate and most acceptable and excellen...

  12. Using applicative software and software tools for the performance of leaching and bio-leaching

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Gocev, Zivko; Zdravev, Zoran; Krstev, Dejan; Zivanovic, Jordan

    2013-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the mean time, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and exce...

  13. The presentation of leaching and bio-leaching from different ores using SIMPLEX EVOP

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Golomeova, Mirjana; Gocev, Zivko

    2013-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the mean time, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and exce...

  14. Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP

    Directory of Open Access Journals (Sweden)

    Xiaoliang Liu

    2017-07-01

    Full Text Available The effect of pyrite and the role of ammonium alcohol polyvinyl phosphate (AAPP during gold leaching in ammoniacal thiosulfate solutions were investigated using pure gold foils. The results showed that pyrite catalyzed the decomposition and also significantly increased the consumption of thiosulfate. This detrimental effect became more severe with increasing pyrite content. Further, the presence of pyrite also substantially slowed the gold leaching kinetics and reduced the overall gold dissolution. The reduction in gold dissolution was found to be caused primarily by the surface passivation of the gold. The negative effects of pyrite, however, can be alleviated by the addition of AAPP. Comparison of zeta potentials of pyrite with and without AAPP suggests that AAPP had adsorbed on the surface of the pyrite and weakened the catalytic effect of pyrite on the thiosulfate decomposition by blocking the contact between the pyrite and thiosulfate anions. AAPP also competed with thiosulfate anions to complex with the cupric ion at the axial coordinate sites, and thus abated the oxidation of thiosulfate by cupric ions. Moreover, the indiscriminate adsorption of AAPP on the surfaces of gold and passivation species prevented the passivation of the gold surface by surface charge and electrostatic repulsion. Therefore, AAPP effectively stabilized the thiosulfate in the solution and facilitated the gold leaching in the presence of pyrite.

  15. Testing the Runoff Tool in Sicilian vineyards: adopting best management practices to prevent agricultural surface runoff

    Science.gov (United States)

    Singh, Manpriet; Dyson, Jeremy; Capri, Ettore

    2016-04-01

    Over the last decades rainfall has become more intense in Sicily, making large proportions of steeply sloping agricultural land more vulnerable to soil erosion, mainly orchards and vineyards (Diodato and Bellocchi 2010). The prevention of soil degradation is indirectly addressed in the European Union's Water Framework Directive (2000/60/EC) and Sustainable Use Directive (2009/128/EC). As a consequence, new EU compliance conditions for food producers requires them to have tools and solutions for on-farm implementation of sustainable practices (Singh et al. 2014). The Agricultural Runoff and Best Management Practice Tool has been developed by Syngenta to help farm advisers and managers diagnose the runoff potential from fields with visible signs of soil erosion. The tool consists of 4 steps including the assessment of three key landscape factors (slope, topsoil permeability and depth to restrictive horizon) and 9 mainly soil and crop management factors influencing the runoff potential. Based on the runoff potential score (ranging from 0 to 10), which is linked to a runoff potential class, the Runoff Tool uses in-field and edge-of-the-field Best Management Practices (BMPs) to mitigate runoff (aligned with advice from ECPA's TOPPS-prowadis project). The Runoff tool needs testing in different regions and crops to create a number of use scenarios with regional/crop specific advice on BMPs. For this purpose the Tool has been tested in vineyards of the Tasca d'Almerita and Planeta wineries, which are large family-owned estates with long-standing tradition in viticulture in Sicily. In addition to runoff potential scores, Visual Soil Assessment (VSA) scores have been calculated to allow for a comparison between different diagnostic tools. VSA allows for immediate diagnosis of soil quality (a higher score means a better soil quality) including many indicators of runoff (Shepherd 2008). Runoff potentials were moderate to high in all tested fields. Slopes were classified as

  16. Laboratory studies on leaching of low grade uranium ores and treatment of low level liquid waste generated by leaching experiments

    International Nuclear Information System (INIS)

    Palabrica, O.T.; Antonino, E.J.; Caluag, L.A.; Villamater, D.

    1980-07-01

    Acid leaching experiments of preconcentrated uranium ore were carried out at a pulp density of 50% solids, using sulfuric acid with sodium chlorate as oxidant. The different leaching parameters considered in this work were temperature, oxidant level and leaching time. In the experimental procedure, the concentration of oxidant and the temperature were varied to determine how they affect the leaching process. Experimental results are illustrated in tabulated form for better interpretation. Uranium analyses were done by fluorimetric and delayed-neutron activation analysis. An anion exchange method using Dowex 1 x 8, 200-400 mesh (Cl - ) was used in treating the low-level liquid waste generated by leaching experiments. The purpose of this treatment was to minimize radioactive contamination in the waste materials and also to recover some of the uranium left in the liquid waste. (author)

  17. Formation, decomposition and cesium adsorption mechanisms of highly alkali-tolerant nickel ferrocyanide prepared by interfacial synthesis

    International Nuclear Information System (INIS)

    Ichikawa, Tsuneki; Yamada, Kazuo; Osako, Masahiro; Haga, Kazuko

    2017-01-01

    Highly alkali-tolerant nickel ferrocyanide was prepared as an adsorbent for preventing the leaching of radioactive cesium from municipal solid waste incinerator fly ash containing large amounts of calcium hydroxide and potassium chloride, which act as an alkaline source and the suppressor for cesium adsorption, respectively. Nickel ferrocyanide prepared by contacting concentrated nickel and ferrocyanide solutions without mixing adsorbed cesium ions in alkaline conditions even the concentration of coexisting potassium ions was more than ten thousand times higher than that of the cesium ions. Large particles of nickel ferrocyanide slowly grew at the interface between the two solutions, which reduced the surface energy of the particles and therefore increased the alkali tolerance. The interfacially-synthesized nickel ferrocyanide was possible to prevent the leaching of radioactive cesium from cement-solidified fly ash for a long period. The mechanisms of the formation, selective cesium adsorption, and alkali-induced decomposition of the nickel ferrocyanide were elucidated. Comparison of the cesium adsorption mechanism with that of the other adsorbents revealed that an adsorbent can selectively adsorb cesium ions without much interference from potassium ions, if the following conditions are fulfilled. 1) The adsorption site is small enough for supplying sufficient electrostatic energy for the dehydration of ions adsorbed. 2) Both the cesium and potassium ions are adsorbed as dehydrated ions. 3) The adsorption site is flexible enough for permitting the penetration of dehydrated ions with the size comparable to that of the site. (author)

  18. Runoff formation in a small mountainous catchment

    Czech Academy of Sciences Publication Activity Database

    Tesař, Miroslav; Šír, Miloslav; Lichner, Ľ.

    2003-01-01

    Roč. 4, č. 2 (2003), s. 265-270 ISSN 1335-6291 R&D Projects: GA AV ČR IAA3060001; GA AV ČR IBS2060104; GA MŽP SE/610/3/00 Grant - others:Slovak Scientific Grant Agency(SK) 2/7065/20; 5th EC Framework Programme(XE) IST-2000-28084 Institutional research plan: CEZ:AV0Z2060917 Keywords : hydrology * rainfall-runoff relationship * small mountainous catchment Subject RIV: DA - Hydrology ; Limnology

  19. Kinetics of Cs adsorption on soils with different mineralogical composition

    International Nuclear Information System (INIS)

    Nakao, Atsushi; Funakawa, Shinya; Kosaki, Takashi

    2004-01-01

    137 Cs is one of the main radioisotopes released into the environment by nuclear powerstation accidents (e.g. Chernobyl) and nuclear weapons tests. Many studies have shown that Cs tends to remain at surface soils due to the high adsorption selectivity of clay minerals for this element. This behavior of the Cs + ion is, however, assumed to vary significantly depending on the mineralogical composition of the soil. The main objective of this study is to analyze the kinetics of Cs adsorption on soils with different mineralogical composition. Soil samples used in this study were Mollisols (Um) and Alfisols (Ua) from Ukraine, Ultisols (Tu) from Thailand and Spodosols (Js) from Japan. The dominant clay species of these soils are montmorillonite (Um, Ua), kaolinite and mica (Tu) and beidellite (Js). The rates of Cs adsorption and Ca or K desorption were measured using a continuous flow method. Soil samples that were previously saturated with Ca 2+ were leached with a 0.75 mmol/l Cs + solution at a constant rate of 2.0 ml/min. The leachate was collected every 10 minutes and the concentrations of Cs + , Ca 2+ and K + of each aliquot were measured by atomic adsorption spectrophotometry (Cs + , Ca 2+ ) and flame spectrophotometry (K + ). The datasets obtained were simulated using the first order kinetic model: y = a(1 - exp(-kt)), where a is the adsorption (desorption) maximum and k the rate constant. It is here assumed that Ca 2+ is desorbed from cation exchange sites and K + desorbed from the frayed edges of micaceous minerals. The values of a obtained for both Cs adsorption and Ca desorption was in the order Js>Um>Tu>Ua, whereas the values of k were in the order Tu>Ua>Um>Js. This result reflects the values of permanent negative charge of clays which are originated from the substitution of cations in the structure of 2:1 clay minerals. The value of a for K + desorption was, however, highest in Tu, suggesting that the values of Cs + -exchangeable K + correspond to the amount

  20. Adsorption and collective paramagnetism

    CERN Document Server

    Selwood, Pierce W

    1962-01-01

    Adsorption and Collective Paramagnetism describes a novel method for studying chemisorption. The method is based on the change in the number of unpaired electrons in the adsorbent as chemisorption occurs. The method is applicable to almost all adsorbates, but it is restricted to ferromagnetic adsorbents such as nickel, which may be obtained in the form of very small particles, that is to say, to ferromagnetic adsorbents with a high specific surface. While almost all the data used illustratively have been published elsewhere this is the first complete review of the subject. The book is addresse

  1. Treatment conditions for the removal of contaminants from road runoff

    OpenAIRE

    Hallberg, Magnus

    2007-01-01

    The pollutant load in road runoff is related to traffic densities and road maintenance activities. Inurbanised areas treatment of road runoff is common and often considered necessary. The pollutantsare partitioned between the particulate and dissolved matter. However, the contaminantstend to have an affinity to the particulate material. Sedimentation, the predominant treatmentmethod for road runoff uses various types of ponds. Design tools used for stormwater treatmentsystems are based on ext...

  2. Short review of runoff and erosion physically based models

    Directory of Open Access Journals (Sweden)

    Gabrić Ognjen

    2015-01-01

    Full Text Available Processes of runoff and erosion are one of the main research subjects in hydrological science. Based on the field and laboratory measurements, and analogous with development of computational techniques, runoff and erosion models based on equations which describe the physics of the process are also developed. Several models of runoff and erosion which describes entire process of genesis and sediment transport on the catchment are described and compared.

  3. Characterization of Urban Runoff Pollution between Dissolved and Particulate Phases

    OpenAIRE

    Wei, Zhang; Simin, Li; Fengbing, Tang

    2013-01-01

    To develop urban stormwater management effectively, characterization of urban runoff pollution between dissolved and particulate phases was studied by 12 rainfall events monitored for five typical urban catchments. The average event mean concentration (AEMC) of runoff pollutants in different phases was evaluated. The AEMC values of runoff pollutants in different phases from urban roads were higher than the ones from urban roofs. The proportions of total dissolved solids, total dissolved nitr...

  4. Snowmelt Runoff: A New Focus of Urban Nonpoint Source Pollution

    OpenAIRE

    Jiunian Guan; Baixing Yan; Hui Zhu; Yingying Xu

    2012-01-01

    Irregular precipitation associated with global climate change had been causing various problems in urban regions. Besides the runoff due to rainfall in summer, the snowmelt runoff in early spring could also play an important role in deteriorating the water quality of the receiving waters. Due to global climate change, the snowfall has increased gradually in individual regions, and snowstorms occur more frequently, which leads to an enhancement of snowmelt runoff flow during the melting season...

  5. Urban Run-off Volumes Dependency on Rainfall Measurement Method

    DEFF Research Database (Denmark)

    Pedersen, L.; Jensen, N. E.; Rasmussen, Michael R.

    2005-01-01

    Urban run-off is characterized with fast response since the large surface run-off in the catchments responds immediately to variations in the rainfall. Modeling such type of catchments is most often done with the input from very few rain gauges, but the large variation in rainfall over small areas...... resolutions and single gauge rainfall was fed to a MOUSE run-off model. The flow and total volume over the event is evaluated....

  6. Improved rainfall-runoff approach using lumped and conceptual modelling

    OpenAIRE

    Durán Barroso, Pablo

    2016-01-01

    Rainfall-runoff quantification is one of the most important tasks in both engineering and watershed management as it allows to identify, forecast and explain watershed response. The division of the rainfall depth between infiltration and runoff has a high level of complexity due to the spatial heterogeneity in real catchments and the temporal precipitation variability, which provide scale effects on the overall runoff volumes. The Natural Resources Conservation Service Curve Number (NRCS CN) ...

  7. Runoff Calculation by Neural Networks Using Radar Rainfall Data

    OpenAIRE

    岡田, 晋作; 四俵, 正俊

    1997-01-01

    Neural networks, are used to calculate runoff from weather radar data and ground rain gauge data. Compared to usual runoff models, it is easier to use radar data in neural network runoff calculation. Basically you can use the radar data directly, or without transforming them into rainfall, as the input of the neural network. A situation with the difficulty of ground measurement is supposed. To cover the area lacking ground rain gauge, radar data are used. In case that the distribution of grou...

  8. Removal of copper from acid wastewater of bioleaching by adsorption onto ramie residue and uptake by Trichoderma viride.

    Science.gov (United States)

    Wang, Buyun; Wang, Kai

    2013-05-01

    A continuous batch bioleaching was built to realize the bioleaching of sewage sludge in large scale. In the treatment, heavy metal in acid wastewater of bioleaching was removed by adsorption onto ramie residue. Then, acid wastewater was reused in next bioleaching batch. In this way, most time and water of bioleaching was saved and leaching efficiency of copper, lead and chromium kept at a high level in continuous batch bioleaching. It was found that residual heavy metal in sewage sludge is highly related to that in acid wastewater after bioleaching. To get a high leaching efficiency, concentration of heavy metal in acid wastewater should be low. Adsorption of copper from acid wastewater onto ramie residue can be described by pseudo first-order kinetics equation and Freundlich isotherm model. Trichoderma viride has the potential to be used for the concentration and recovery of heavy metal adsorbed onto ramie residue. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Quantifying runoff water quality characteristics from nurseries and avocado groves subjected to altered irrigation and fertilizer regimes

    Science.gov (United States)

    Samant, S. A.; Beighley, R. E.

    2007-12-01

    In agriculture, improper, excessive or poorly timed irrigation and fertilizer applications can result in increased pollutants in runoff and degraded water quality. Specifically, the cultivation of salt sensitive plants and nurseries require significant irrigation and fertilizer that leads to high nutrient leaching. In southern California, a large producer of Avocados and nursery plant, waterways are often subjected to elevated nutrient concentrations, which stress the aquatic ecosystem. In this research, the specific objectives are to determine optimal irrigation and fertilizer application rates for minimizing nutrient and sediment export from avocado groves and nurseries. Altered irrigation and fertilizer application experiments will be implemented and monitored at the San Diego State University's Santa Margarita Ecological Reserve, which contains a 12 ha avocado grove and newly constructed 0.4 ha nursery. The study will last for twelve months, with runoff from natural rainfall or irrigation sampled and analyzed for nutrient concentrations on a monthly basis. The growth rate, leaf nutrient content and plant yield will also be monitored monthly. The nursery site is divided into eight plots (13.5-m x 13.5-m), with each plot containing 1200 plants consisting of four commonly used landscaping varieties in southern California. The avocado grove of the Hass variety is divided into four 1-ha plots. The experimental plots represent combinations of irrigation and fertilization practices with different methods and rates. In all cases, irrigation is fully automated based on soil moisture. To assess the effectiveness of the altered irrigation and fertilizer strategies, runoff water quality and plant yield will be compared to controlled treatments. This research is intended to provide a better understanding of how irrigation and fertilizer management can be used for the long-term reduction of nutrients in the Santa Margarita Watershed, which in turn will lead to improved

  10. Use of 15N-labelled nitrogen deposition to quantify the source of nitrogen in runoff at a coniferous-forested catchment at Gardsjoen, Sweden

    International Nuclear Information System (INIS)

    Kjonaas, O. Janne; Wright, Richard F.

    2007-01-01

    To determine the source of dissolved inorganic nitrogen (N) in runoff, approx. 35 kg N enriched with the stable isotope 15 N (2110 per mille δ 15 N) was added to a mature coniferous forested catchment for one whole year. The total N input was approx. 50 kg ha -1 year -1 . The enrichment study was part of a long-term whole-catchment ammonium nitrate addition experiment at Gardsjoen, Sweden. The 15 N concentrations in precipitation, throughfall, runoff and upper forest floor were measured prior to, during, and 3-9 years following the 15 N addition. During the year of the 15 N addition the δ 15 N level in runoff largely reflected the level in incoming N, indicating that the leached NO 3 - came predominantly from precipitation. Only 1.1% of the incoming N was lost during the year of the tracer addition. The cumulative loss of tracer N over a 10-year period was only 3.9% as DIN and 1.1% as DON. - 15 N tracer addition showed that initially the main source of NO 3 - in runoff was N from atmospheric deposition

  11. Surface runoff in flat terrain: How field topography and runoff generating processes control hydrological connectivity

    NARCIS (Netherlands)

    Appels, W.M.; Bogaart, P.W.; Bogaart, P.W.; Zee, van der S.E.A.T.M.

    2016-01-01

    In flat lowland agricultural catchments in temperate climate zones with highly permeable sandy soils, surface runoff is a rare process with a large impact on the redistribution of sediments and solutes and stream water quality. We examine hydrological data obtained on two field sites in the

  12. Study on Shale Adsorption Equation Based on Monolayer Adsorption, Multilayer Adsorption, and Capillary Condensation

    OpenAIRE

    Chen, Qing; Tian, Yuanyuan; Li, Peng; Yan, Changhui; Pang, Yu; Zheng, Li; Deng, Hucheng; Zhou, Wen; Meng, Xianghao

    2017-01-01

    Shale gas is an effective gas resource all over the world. The evaluation of pore structure plays a critical role in exploring shale gas efficiently. Nitrogen adsorption experiment is one of the significant approaches to analyze pore size structure of shale. Shale is extremely heterogeneous due to component diversity and structure complexity. Therefore, adsorption isotherms for homogeneous adsorbents and empirical isotherms may not apply to shale. The shape of adsorption-desorption curve indi...

  13. Predicting Surface Runoff from Catchment to Large Region

    Directory of Open Access Journals (Sweden)

    Hongxia Li

    2015-01-01

    Full Text Available Predicting surface runoff from catchment to large region is a fundamental and challenging task in hydrology. This paper presents a comprehensive review for various studies conducted for improving runoff predictions from catchment to large region in the last several decades. This review summarizes the well-established methods and discusses some promising approaches from the following four research fields: (1 modeling catchment, regional and global runoff using lumped conceptual rainfall-runoff models, distributed hydrological models, and land surface models, (2 parameterizing hydrological models in ungauged catchments, (3 improving hydrological model structure, and (4 using new remote sensing precipitation data.

  14. Prediction and optimization of runoff via ANFIS and GA

    Directory of Open Access Journals (Sweden)

    D.K. Ghose

    2013-06-01

    Full Text Available In planning of water resource projects, the estimation of the availability of water plays an important role. The first step in the water availability estimation is the computation of runoff resulting from the precipitation on river catchments. The length of the runoff measured in a stream may be of short period or long period depending upon the catchment characteristics. Keeping this in mind the present work is focused on two different model generation. In the first phase of this study, runoff rating curves are developed considering present day water level (H(t as input and present day runoff (Q(t as the model output. In the second phase of the study runoff prediction models are developed considering 1 day lag water level (H(t − 1, 2 day lag water level (H(t − 2 and 1 day lag runoff (Q(t − 1 as inputs and 1 day ahead runoff (Q(t + 1 as the output of the model. Models developed and used for prediction of runoff are Non-Linear Multiple Regression (NLMR and Adaptive Neuro-Fuzzy Inference System (ANFIS. Both the models were trained and tested to predict the performance of models. Genetic Algorithm (GA is then coupled with NLMR model to obtain the condition of hydrological parameter for which the runoff is maximum.

  15. The Idiosyncrasies of Storage and Implications for Catchment Runoff (Invited)

    Science.gov (United States)

    Spence, C.

    2010-12-01

    Because water goes into storage when it rains, perhaps the entire concept of a direct rainfall-runoff process is erroneous and misleading. Perhaps the runoff generation process is merely the conversion of storage to runoff. Using this perspective as a foundation, it then becomes important to understand how catchments retain water, where this storage is distributed and what controls the distribution of this storage. There is a growing body of observational evidence that the idiosyncrasies of storage in the catchment are crucial for runoff generation. These idiosyncrasies are important enough that some hydrologists are questioning assumptions of steady state, linearity, and topographic control in existing theories and algorithms of runoff generation. For instance, thresholds that control the release of water have been identified at many scales and in many landscapes. Hysteresis in storage-runoff relationships at all scales manifest because of these thresholds. Because storage thresholds at a range of scales are now known to be important for runoff response, connectivity has become an important concept crucial to interpreting catchment runoff response. There appears to be growing acceptance of such ideas as thresholds, hysteresis and connectivity in the hydrological literature. Theoretical development and model parameterization have begun, but there remains much work to resolve these field observations. In particular, our community should strive to investigate the relevance of storage-runoff relationships partly through innovative measurement techniques and the development of model structures appropriate for the requisite testing of these theories in a diversity of landscapes.

  16. Sampling and chemical analysis of urban street runoff

    International Nuclear Information System (INIS)

    Daub, J.; Striebel, T.; Robien, A.; Herrmann, R.

    1993-01-01

    In order to characterize the environmentally relevant physical and chemical properties of urban street runoff, an automatic sampling device was developed. Precipitation samples were collected together with runoff samples. Organic and inorganic compounds were analysed in the runoff. Dissolved and particle bound substances were analysed separately. The concentrations in runoff are generally considerably higher than in precipitation. Concentrations of lead, fluoranthene and benzo(a)pyrene, in particular are higher in runoffs at sites with high traffic densities than at sites with low traffic densities. Preceding dry period normally has no effect on the measured concentrations. The typical chemograph of a dissolved substance shows a maximum at the beginning of the event dropping quickly to a minimum, which often coincides with the maximum in runoff rate. A slight rise is observed with decreasing runoff rates at the end of the event. Applying a mathematical model, chemographs may be described by three terms: - Relatively large amounts of easily soluble material at the beginning of the event decrease with increasing runoff. Conservative behaviour is assumed. - A part which varies inversely to the runoff rate. This term assumes zero-order kinetics; the amount dissolved from surfaces is constant with time. - A small constant term. Concentrations of particle bound substances correlate with amounts of total suspended solids. Frequently a negative correlation between the specific concentration of substances and the concentration of total suspended solids is observed. (orig.) [de

  17. Leach testing of waste glasses under near-saturation conditions

    International Nuclear Information System (INIS)

    Strachan, D.M.; Grambow, B.

    1983-11-01

    Two waste glasses, MCC 76 to 68 and C31 to 3, were leached in deionized water and 0.001 M MgCl 2 for periods up to 158 days. At 57 days the gel layer was removed from some of the specimens and leaching continued for up to 100 days. Results from leaching in deionized water showed that the gel layer was not protective. Results from leaching in 0.001 M MgCl 2 are in good agreement with the predicted results obtained from the use of the PHREEQE geochemical code and with sepiolite [Mg 2 Si 3 O 6 (OH) 4 ] as the Mg-bearing precipitate. Both B and Si were predicted and observed to increase with increasing glass dissolution while maintaining sepiolite solubility. Both MCC 76 to 68 and C31 to 3 glasses showed increased leaching in 0.001 M MgCl 2 upon removal of the layer. This suggests a leaching mechanism whereby leaching is driven by the formation of an alteration product

  18. Defense High-Level Waste Leaching Mechanisms Program. Final report

    International Nuclear Information System (INIS)

    Mendel, J.E.

    1984-08-01

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 90 0 C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations

  19. Technique for in situ leach simulation of uranium ores

    International Nuclear Information System (INIS)

    Grant, D.C.; Seidel, D.C.; Nichols, I.L.

    1985-01-01

    In situ uranium mining offers the advantages of minimal environmental disturbance, low capital and operating costs, and reduced mining development time. It is becoming an increasingly attractive mining method for the recovery of uranium from secondary ore deposits. In order to better understand the process, a laboratory technique was developed and used to study and simulate both the chemical and physical phenomena occurring in ore bodies during in situ leaching. The laboratory simulation technique has been used to determine effects of leaching variables on permeability, uranium recovery, and post-leach aquifer restoration. This report describes the simulation system and testing procedure in sufficient detail to allow the construction of the system, and to perform the desired leaching tests. With construction of such a system, in situ leaching of a given ore using various leach conditions can be evaluated relatively rapidly in the laboratory. Not only could optimum leach conditions be selected for existing ore bodies, but also exploitation of new ore bodies could be accelerated. 8 references, 8 figures, 2 tables

  20. Leach rate studies on glass containing actual radioactive waste

    International Nuclear Information System (INIS)

    Walker, D.D.; Wiley, J.R.; Dukes, M.D.; LeRoy, J.H.

    1980-01-01

    Borosilicate glass containing radioactive wastes from the Savannah River Plant have been leached for 900 days. The International Standards Organization's (ISO) static leach test procedure was used on glass buttons in various leachants. Leach rates based on 90 Sr and 137 Cs analyses were similar: 2 x 10 -8 to 3 x 10 -8 g/(cm 2 )(d) in distilled water, 1 x 10 -8 to 3 x 10 -7 g/(cm 2 )(d) in pH 7 buffer, 3 x 10 -7 to 7 x 10 -7 g/(cm 2 )(d) in pH 9 buffer, and 7 x 10 -6 to 8 x 10 -5 g/(cm 2 )(d) in pH 4 buffer. Rates based on Pu analyses were the same as above in distilled water and pH 9 buffer, but were lower by an order of magnitude in pH 4 and pH 7 buffers. Almost all leach rates remained constant between 200 and 900 days of leaching. Increasing the concentration of the buffering agents had no effect on the leach rates at pH 7 (phosphate) and pH 9 (carbonate), but dramatically increased the rates at pH 4 (acetate). Leach rates did not differ significantly between high aluminum and high iron waste glasses

  1. Thiosulfate leaching of gold from waste mobile phones.

    Science.gov (United States)

    Ha, Vinh Hung; Lee, Jae-chun; Jeong, Jinki; Hai, Huynh Trung; Jha, Manis K

    2010-06-15

    The present communication deals with the leaching of gold from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a copper-ammonia-thiosulfate solution, as an alternative to the conventional and toxic cyanide leaching of gold. The influence of thiosulfate, ammonia and copper sulfate concentrations on the leaching of gold from PCBs of waste mobile phones was investigated. Gold extraction was found to be enhanced with solutions containing 15-20 mM cupric, 0.1-0.14 M thiosulfate, and 0.2-0.3 M ammonia. Similar trends were obtained for the leaching of gold from two different types of scraps and PCBs of waste mobile phones. From the scrap samples, 98% of the gold was leached out using a solution containing 20 mM copper, 0.12 M thiosulfate and 0.2 M ammonia. Similarly, the leaching of gold from the PCBs samples was also found to be good, but it was lower than that of scrap samples in similar experimental conditions. In this case, only 90% of the gold was leached, even with a contact time of 10h. The obtained data will be useful for the development of processes for the recycling of gold from waste mobile phones. Copyright 2010 Elsevier B.V. All rights reserved.

  2. Leaching experiment of cement solidified waste form under unsaturated condition

    International Nuclear Information System (INIS)

    Wang Zhiming; Yao Laigen; Li Shushen; Zhao Yingjie; Cai Yun; Li Dan; Han Xinsheng; An Yongfeng

    2003-01-01

    A device for unsaturated leaching experiments was designed and built up. 8 different sizes, ranging from 40.2 cm 3 to 16945.5 cm 3 , of solidified waste form were tested in the experiment. 5 different water contents, from 0.15 to 0.40, were used for the experiment. The results show that the cumulative leaching fraction increases with water content when the sizes of the forms are equal to and less than 4586.7 cm 3 , for example, the ratios of the cumulative leaching fractions are between 1.24-1.41 under water content of 0.35 and 0.15 on 360 day of Teaching. It can also be seen that the cumulative leaching fraction under higher water content is close to that under saturated condition. The cumulative leaching fraction decreases with size of the form. Maximum leached depth of the solidified waste forms is about 2.25 cm after one year Teaching. Moreover, it has no clear effect on cumulative leaching fraction that sampling or non-sampling during the experiment

  3. Defense High-Level Waste Leaching Mechanisms Program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mendel, J.E. (compiler)

    1984-08-01

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 90/sup 0/C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations.

  4. Analysis of SPR salt cavern remedial leach program 2013.

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Paula D.; Gutierrez, Karen A.; Lord, David L.; Rudeen, David Keith

    2013-09-01

    The storage caverns of the US Strategic Petroleum Reserve (SPR) exhibit creep behavior resulting in reduction of storage capacity over time. Maintenance of oil storage capacity requires periodic controlled leaching named remedial leach. The 30 MMB sale in summer 2011 provided space available to facilitate leaching operations. The objective of this report is to present the results and analyses of remedial leach activity at the SPR following the 2011 sale until mid-January 2013. This report focuses on caverns BH101, BH104, WH105 and WH106. Three of the four hanging strings were damaged resulting in deviations from normal leach patterns; however, the deviations did not affect the immediate geomechanical stability of the caverns. Significant leaching occurred in the toes of the caverns likely decreasing the number of available drawdowns until P/D ratio criteria are met. SANSMIC shows good agreement with sonar data and reasonably predicted the location and size of the enhanced leaching region resulting from string breakage.

  5. Leaching of CCA-treated wood: implications for waste disposal

    International Nuclear Information System (INIS)

    Townsend, Timothy; Tolaymat, Thabet; Solo-Gabriele, Helena; Dubey, Brajesh; Stook, Kristin; Wadanambi, Lakmini

    2004-01-01

    Leaching of arsenic, chromium, and copper from chromated copper arsenate (CCA)-treated wood poses possible environmental risk when disposed. Samples of un-weathered CCA-treated wood were tested using a variety of the US regulatory leaching procedures, including the toxicity characteristic leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), extraction procedure toxicity method (EPTOX), waste extraction test (WET), multiple extraction procedure (MEP), and modifications of these procedures which utilized actual MSW landfill leachates, a construction and demolition (C and D) debris leachate, and a concrete enhanced leachate. Additional experiments were conducted to assess factors affecting leaching, such as particle size, pH, and leaching contact time. Results from the regulatory leaching tests provided similar results with the exception of the WET, which extracted greater quantities of metals. Experiments conducted using actual MSW leachate, C and D debris leachate, and concrete enhanced leachate provided results that were within the same order of magnitude as results obtained from TCLP, SPLP, and EPTOX. Eleven of 13 samples of CCA-treated dimensional lumber exceeded the US EPA's toxicity characteristic (TC) threshold for arsenic (5 mg/L). If un-weathered arsenic-treated wood were not otherwise excluded from the definition of hazardous waste, it frequently would require management as such. When extracted with simulated rainwater (SPLP), 9 of the 13 samples leached arsenic at concentrations above 5 mg/L. Metal leachability tended to increase with decreasing particle size and at pH extremes. All three metals leached above the drinking water standards thus possibly posing a potential risk to groundwater. Arsenic is a major concern from a disposal point of view with respect to ground water quality

  6. Using microbiological leaching method to remove heavy metals from sludge

    Directory of Open Access Journals (Sweden)

    Zhuyu Gu

    2017-01-01

    Full Text Available Microbial leaching is one of the most effective methods to remove heavy metals from sludge. In the conducted researches, the sludge samples were processed with Thiobacillus ferrooxidans and Thiobacillus thiooxidans obtained via cultivation, extraction and purification processes. Heavy metals such as Pb, Cd, Cu and Ni were leached from sludge by Thiobacillus ferrooxidans and Thiobacillus thiooxidans within different substrate concentration and pH value conditions. It is defined that from the point of view of economy and efficiency the optimal concentration of FeSO4.7H2O and sulfur for bio-leaching process was 0.2 g. The leaching rates of heavy metals such as Pb, Cd, Cu and Ni of the same concentration were 74.72%, 81.54%, 70.46% and 77.35% respectively. However, no significant differences depending on the pH value among the leaching rates were defined, even for the pH value of 1.5. Along with the removal of heavy metals from sludge, the organic matter, N, P, K were also leached to some extent. The losing rate of phosphorus was the highest and reached 38.44%. However, the content of organic matter, N, P, K in the processed sludge were higher in comparison with level I of the National Soil Quality Standards of China. Ecological risk of heavy metals in sludge before and after leaching was assessed by Index of Geo-accumulation (Igeo and comprehensive potential risk (RI. The results of research defined that the content of heavy metals in sludge meets the level of low ecological risk after leaching and their contents is lower in comparison with the National Agricultural Sludge Standard of China. Sludge leached by biological methods is possible to use for treatment for increasing soil fertility.

  7. Leach behavior of hydrofracture grout incorporating radioactive wastes

    International Nuclear Information System (INIS)

    Moore, J.G.; Godbee, H.W.; Kibbey, A.H.

    1976-01-01

    Rates at which Sr, Cs, Pu, and Cm are leached from hydrofracture grout were measured. The fraction of an isotope leached varied with the square root of time if the leachant was replaced more frequently than once per day, but was inhibited or depressed if replacement was made less often. The amount of Sr or Cs leached from the grout varied directly with the degree of drying during curing and inversely with the time of curing. Of the clay additives studied for enhancing cesium retention, Grundite, while satisfactory, was the least effective. In general, the isotope leach rate followed the order: Cs greater than Sr greater than Cm greater than Pu. The amount leached as a function of the leachant varied in the order: distilled water greater than tap water greater than grout water. Concentrating the waste by a factor of up to 4 before grouting had little effect on the leach rate. Comparison with results for other products indicates that the grout can provide leach rates comparable to those for wastes incorporated into borosilicate glass. Theoretical relationships that consider diffusion and instantaneous reaction (an equilibrium or time-dependent relationship between mobile and immobile forms of a species) were in good agreement with the data for the 28-day-cured grout when the leachant was initially replaced twice per day. The credibility of laboratory results with simulated waste was substantiated by a short-term continuous leach test made on a fragment of a core sample of actual hydrofracture grout. The modified effective diffusivities (10 -11 to 10 -10 cm 2 /s, equivalent to a leach rate of the order of 10 -7 g cm -2 day -1 ) for Sr and Cs calculated from these data are comparable to laboratory values. 17 figures, 5 tables

  8. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westsik, Joseph H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jung, H. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-09

    This report describes the results from long-term laboratory leach tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams. Specific objectives of the Cast Stone long-term leach tests described in this report focused on four activities: 1. Extending the leaching times for selected ongoing EPA-1315 tests on monoliths made with LAW simulants beyond the conventional 63-day time period up to 609 days reported herein (with some tests continuing that will be documented later) in an effort to evaluate long-term leaching properties of Cast Stone to support future performance assessment activities. 2. Starting new EPA-1315 leach tests on archived Cast Stone monoliths made with four LAW simulants using two leachants (deionized water [DIW] and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water [VZP]). 3. Evaluating the impacts of varying the iodide loading (starting iodide concentrations) in one LAW simulant (7.8 M Na Hanford Tank Waste Operations Simulator (HTWOS) Average) by manufacturing new Cast Stone monoliths and repeating the EPA-1315 leach tests using DIW and the VZP leachants. 4. Evaluating the impacts of using a non-pertechnetate form of Tc that is present in some Hanford tanks. In this activity one LAW simulant (7.8 M Na HTWOS Average) was spiked with a Tc(I)-tricarbonyl gluconate species and then solidified into Cast Stone monoliths. Cured monoliths were leached using the EPA-1315 leach protocol with DIW and VZP. The leach results for the Tc-Gluconate Cast Stone monoliths were compared to Cast Stone monoliths pertechnetate.

  9. Water erosion in surface soil conditions: runoff velocity, concentration and D50 index of sediments in runoff

    OpenAIRE

    Ramos,Júlio César; Bertol,Ildegardis; Barbosa,Fabrício Tondello; Bertól,Camilo; Mafra,Álvaro Luiz; Miquelluti,David José; Mecabô Júnior,José

    2016-01-01

    ABSTRACT Water erosion and contamination of water resources are influenced by concentration and diameter of sediments in runoff. This study aimed to quantify runoff velocity and concentration and the D50 index of sediments in runoff under different soil surface managements, in the following treatments: i) cropped systems: no-tilled soil covered by ryegrass (Lolium multiflorum Lam.) residue, with high soil cover and minimal roughness (HCR); no tilled soil covered by vetch (Vicia sativa L.) res...

  10. Perceived agricultural runoff impact on drinking water.

    Science.gov (United States)

    Crampton, Andrea; Ragusa, Angela T

    2014-09-01

    Agricultural runoff into surface water is a problem in Australia, as it is in arguably all agriculturally active countries. While farm practices and resource management measures are employed to reduce downstream effects, they are often either technically insufficient or practically unsustainable. Therefore, consumers may still be exposed to agrichemicals whenever they turn on the tap. For rural residents surrounded by agriculture, the link between agriculture and water quality is easy to make and thus informed decisions about water consumption are possible. Urban residents, however, are removed from agricultural activity and indeed drinking water sources. Urban and rural residents were interviewed to identify perceptions of agriculture's impact on drinking water. Rural residents thought agriculture could impact their water quality and, in many cases, actively avoided it, often preferring tank to surface water sources. Urban residents generally did not perceive agriculture to pose health risks to their drinking water. Although there are more agricultural contaminants recognised in the latest Australian Drinking Water Guidelines than previously, we argue this is insufficient to enhance consumer protection. Health authorities may better serve the public by improving their proactivity and providing communities and water utilities with the capacity to effectively monitor and address agricultural runoff.

  11. The geomorphic structure of the runoff peak

    Directory of Open Access Journals (Sweden)

    R. Rigon

    2011-06-01

    Full Text Available This paper develops a theoretical framework to investigate the core dependence of peak flows on the geomorphic properties of river basins. Based on the theory of transport by travel times, and simple hydrodynamic characterization of floods, this new framework invokes the linearity and invariance of the hydrologic response to provide analytical and semi-analytical expressions for peak flow, time to peak, and area contributing to the peak runoff. These results are obtained for the case of constant-intensity hyetograph using the Intensity-Duration-Frequency (IDF curves to estimate extreme flow values as a function of the rainfall return period. Results show that, with constant-intensity hyetographs, the time-to-peak is greater than rainfall duration and usually shorter than the basin concentration time. Moreover, the critical storm duration is shown to be independent of rainfall return period as well as the area contributing to the flow peak. The same results are found when the effects of hydrodynamic dispersion are accounted for. Further, it is shown that, when the effects of hydrodynamic dispersion are negligible, the basin area contributing to the peak discharge does not depend on the channel velocity, but is a geomorphic propriety of the basin. As an example this framework is applied to three watersheds. In particular, the runoff peak, the critical rainfall durations and the time to peak are calculated for all links within a network to assess how they increase with basin area.

  12. Novel precipitation technique for uranium recovery from carbonate leach solutions

    International Nuclear Information System (INIS)

    Sujoy Biswas; Rupawate, V.H.; Hareendran, K.N.; Roy, S.B.; Chakravartty, J.K.

    2015-01-01

    The recovery of uranium from carbonate ore leach solution was studied using novel precipitation method. The uranium from leach liquor was recovered as magnesium diuranate with NaOH in presence of trace amount of Mg 2+ . Effects of various parameters such as addition of H 2 SO 4 , MgO, MgSO 4 as well as NaOH were investigated for maximum uranium recovery. Overall uranium recovery of the process was 97 % with improved particle size (∼57 µm). Based on the experimental findings, a process flow-sheet was developed for uranium recovery from carbonate ore leach solution with a uranium concentration of <1 g/L. (author)

  13. The Iron Removal in Marmatite Concentrate Pressure Leaching Process

    Science.gov (United States)

    Wen-bo, LUO; Ji-kun, WANG; Yin, GAN

    2018-01-01

    To modify the pressure leaching technology of horizontal autoclave using marmatite concentrate, an appropriate increase in the pulp’s residence time in the horizontal autoclave is required. This increase will provide sufficient time for leaching to be completed in the first three chambers of the horizontal autoclave. Adding zinc oxide ore and potassium sulfate in the fourth chamber of the horizontal autoclave is needed to complete preliminary neutralization and iron precipitation in the horizontal autoclave. The pilot plant experimental results of the proposed technology are satisfactory, further shortening the process of pressure leaching and improving its economic efficiency.

  14. Present and future: heap leaching of uranium ore in China

    International Nuclear Information System (INIS)

    Li Jianhua

    2010-01-01

    Based on small and disperse uranium deposits, and low grade ores, heap leaching has been developed as the dominating technique in the uranium production of China. It is indicated that heap leaching technique has such advantages as less capital, low cost, low power consumption and water consumption. At the meanwhile, heap leaching technique presents shortcomings of poor adaptability and low recovery rate. In order to meet the oncoming enormous demand of nuclear power, great effort shall be put on research of new technology, new equipment, new material. (authors)

  15. Hydrodynamics and mass transfer in trickle leaching process

    International Nuclear Information System (INIS)

    Jin Suoqing; Xiang Qinfang; Guo Jianzheng

    1995-01-01

    The initial research results of the hydrodynamic behavior and mass transfer of the trickle leaching process are summarized. It was shown that the dropping mode, the height of uranium ore heap and the flow rate of the dropping fluid affect the mass transfer of the trickle leaching process. Based on the concept of the keeping form of liquid in ore particle bed and the diffusion in porous medium, a mass transfer pattern, i.e. 'double-membrane transfer process' controlled by porous diffusion, was presented and proved for trickle leaching process

  16. Leaching of heavy metals from timah langat amang

    International Nuclear Information System (INIS)

    Shukri bin Othman

    1990-01-01

    Accelerated leaching studies of amang from Timah Langat for heavy metals showed that the material was rather stable. From almost 24 types of heavy metals contained in the material, the metal that leached out most was Al, followed by Pb, U, Cu, Mn, Fe, Mg, Y and La but at smaller quantities. The studies also showed that amang was very porous. The high seepage rate resulted in the solubilities of the metals not reaching equilibrium. In that situation, the leaching of heavy metals from amang was dependent on the seepage rate of water, the height of the material, the volume of water that seeped through and the solubility of the metals

  17. Polluted rainwater runoff from waste recovery and recycling companies: Determination of emission levels associated with the best available techniques.

    Science.gov (United States)

    Huybrechts, D; Verachtert, E; Vander Aa, S; Polders, C; Van den Abeele, L

    2016-08-01

    Rainwater falling on outdoor storage areas of waste recovery and recycling companies becomes polluted via contact with the stored materials. It contains various pollutants, including heavy metals, polycyclic aromatic hydrocarbons and polychlorinated biphenyls, and is characterized by a highly fluctuating composition and flow rate. This polluted rainwater runoff is legally considered as industrial wastewater, and the polluting substances contained in the rainwater runoff at the point of discharge, are considered as emissions into water. The permitting authorities can set emission limit values (discharge limits) at the point of discharge. Best available techniques are an important reference point for setting emission limit values. In this paper, the emission levels associated with the best available techniques for dealing with polluted rainwater runoff from waste recovery and recycling companies were determined. The determination is based on an analysis of emission data measured at different companies in Flanders. The data show that a significant fraction of the pollution in rainwater runoff is associated with particles. A comparison with literature data provides strong indications that not only leaching, but also atmospheric deposition play an important role in the contamination of rainwater at waste recovery and recycling companies. The prevention of pollution and removal of suspended solids from rainwater runoff to levels below 60mg/l are considered as best available techniques. The associated emission levels were determined by considering only emission data from plants applying wastewater treatment, and excluding all samples with suspended solid levels >60mg/l. The resulting BAT-AEL can be used as a reference point for setting emission limit values for polluted rainwater runoff from waste recovery and recycling companies. Since the BAT-AEL (e.g. 150μg/l for Cu) are significantly lower than current emission levels (e.g. 300μg/l as the 90% percentile and 4910

  18. Adsorption and desorption for dynamics transport of hexavalent chromium Cr(Ⅵ) in soil column

    Science.gov (United States)

    Tong, J.

    2017-12-01

    Batch experiments have been carried out to study the adsorption of heavy metals in soils, and the migration and transformation of hexavalent chromium Cr(Ⅵ) in the soil of a vegetable base were studied by dynamic adsorption and desorption soil column experiments. The aim of this study was to investigate the effect of initial concentration and pH value on the adsorption process of Cr(Ⅵ). Breakthrough curve were used to evaluate the capacity of Cr(Ⅵ) adsorption in soil columns. The results show that the higher the initial concentration, the worse the adsorption capacity of Cr(Ⅵ). The adsorption of Cr(Ⅵ) was strongly sensitive to pH value. The capacity of Cr(Ⅵ) adsorption is maximized at very low pH value. This may be due to changes in pH that cause a series of complex reactions in Cr(Ⅵ). In a strongly acidic environment, the reaction of Cr(Ⅵ) with hydrogen ions is accompanied by the formation of Cr3+, which reacts with the soil free iron-aluminum oxide to produce hydroxide in the soil. The results of the desorption experiments indicate that Cr(Ⅵ) is more likely to leach from this soil, but if the eluent is strong acid solution, the leaching process will be slow and persistent. The program CXTFIT was used to fit the breakthrough curve to estimate parameters. The results of the calculation of the dispersion coefficient (D) can be obtained by this program. The two-site model fit the breakthrough curve data of Cr(Ⅵ) well, and the parameters calculated by CXTFIT can be used to explain the behavior of Cr(Ⅵ) migration and transformation in soil columns. When pH=2, the retardation factor (R) reach at 79.71 while the value of the R is generally around 10 in other experiments. The partitioning coefficient β shows that more than half of the adsorption sites are rate-limited in this adsorption process and non-equilibrium effects the Cr(Ⅵ) transport process in this soil.

  19. Long-term Effects of Organic Waste Fertilizers on Soil Structure, Tracer Transport, and Leaching of Colloids.

    Science.gov (United States)

    Lekfeldt, Jonas Duus Stevens; Kjaergaard, Charlotte; Magid, Jakob

    2017-07-01

    Organic waste fertilizers have previously been observed to significantly affect soil organic carbon (SOC) content and soil structure. However, the effect of organic waste fertilizers on colloid dispersibility and leaching of colloids from topsoil has not yet been studied extensively. We investigated how the repeated application of different types of agricultural (liquid cattle slurry and solid cattle manure) and urban waste fertilizers (sewage sludge and composted organic household waste) affected soil physical properties, colloid dispersion from aggregates, tracer transport, and colloid leaching from intact soil cores. Total porosity was positively correlated with SOC content. Yearly applications of sewage sludge increased absolute microporosity (pores 30 μm) compared with the unfertilized control, whereas organic household waste compost fertilization increased both total porosity and the absolute porosity in all pore size classes (though not significant for 100-600 μm). Treatments receiving large amounts of organic fertilizers exhibited significantly lower levels of dispersible colloids compared with an unfertilized control and a treatment that had received moderate applications of cattle slurry. The content of water-dispersible colloids could not be explained by a single factor, but differences in SOC content, electrical conductivity, and sodium adsorption ratio were important factors. Moreover, we found that the fertilizer treatments did not significantly affect the solute transport properties of the topsoil. Finally, we found that the leaching of soil colloids was significantly decreased in treatments that had received large amounts of organic waste fertilizers, and we ascribe this primarily to treatment-induced differences in effluent electrical conductivity during leaching. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  20. New developments for localized adsorption

    International Nuclear Information System (INIS)

    Boudh-hir, M.E.

    1989-02-01

    Using the diagrammatic expansion, new developments for localized adsorption are found. It is proved that the correlations in the system, in the absence of the attractive site potential, and the periodicity of the sites play a fundamental role in the adsorption phenomena. 14 refs, 2 figs, 2 tabs

  1. Leaching of transuranics observed in lysimeter experiments

    International Nuclear Information System (INIS)

    Eriksson, A.; Fredriksson, L.

    1994-01-01

    Transuranic elements in fallout are generally bound in oxide particles, size from submicron to several microns. During the fallout they can be intercepted on plant covers or reach the soil surface. The particles can be re-suspended to the air and reach other residence sites, be linked into the food chain or be redistributed in other ways (Cf Essington et al. 1976) before eventually being incorporated into the soil. The fate of such particles in the soil depends on the size and on the nature of the particulate matter and on environmental factors, the climate and the properties of the soil. In a dry climate the particles tend to be kept intact long time, (Schulz et al. 1976) and they are more easily redistributed than in a humid climate with plant covered moist and living soils. In the former the particles move more easily in the soil profile than in the latter, the particle matter is very slowly dissolved and the average availability of the deposited nuclides for plant uptake can be assumed to be comparatively low. The downward movements of the particles or nuclide compounds bound to small soil particles are enhanced by the swelling and shrinking of soil caused by absorption and depletion of water during the season. Cracks and fissures are created and closed several times a year in soils rich in colloidal material. Sandy soils with coarse material have less cracks, but in dry conditions the empty pore space may allow transport of fine particles. The coarser material also has less specific area and sorption capacity. The nuclide compounds leached with the drainage water in coarse soils should be less retarded than in clays (Cf. Rai and Serne, 1977; Nishita and Haug, 1979 and Rai et al., 1980). The lysimeter installation used for the study reported below was primarily designed to study the plant uptake of transuranics from a number of Swedish soils. However, as such an installation in many ways well simulate field conditions and at the same time is a closed system

  2. Evaluation of the leaching behavior of incineration bottom ash using seawater: A comparison with standard leaching tests.

    Science.gov (United States)

    Lin, Wenlin Yvonne; Heng, Kim Soon; Nguyen, Minh Quan; Ho, Jin Rui Ivan; Mohamed Noh, Omar Ahmad Bin; Zhou, Xue Dong; Liu, Alec; Ren, Fei; Wang, Jing-Yuan

    2017-04-01

    Batch and column tests were conducted on untreated incineration bottom ash (IBA) samples from two incineration plants in Singapore, using seawater as the leachant. The main objective of this study was to investigate the change in the leaching behavior of certain elements (i.e. As, Cd, Cr, Cu, Ni, Pb, Sb, Se and Zn) when IBA comes into contact with seawater. Such an investigation using seawater as leachant was not commonly carried out when investigating leaching behavior in IBA. The leaching tests were then carried out on the same IBA samples using DI water, as a comparison. Lower level of leaching was observed for Pb and Zn when seawater was used as the leachant. Cr and Sb showed significant cumulative release at Liquid-to-Solids (L/S) ratio 5 in the seawater column leaching. The influence of Dissolved Organic Carbon (DOC) on Cu leaching seems to decrease after L/S 2 when using seawater in the column test. Although the leaching behavior of IBA was affected when seawater was used, for the column test, there was no significant difference during the initial release when compared to DI water. The initial L/S fractions collected were important as the low L/S ratios represent the pore water concentration and the maximum output in an actual application. The results from this study would be useful for the future study on using IBA in marine applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Leaching behaviour of incineration bottom ash in a reuse scenario: 12years-field data vs. lab test results.

    Science.gov (United States)

    Di Gianfilippo, Martina; Hyks, Jiri; Verginelli, Iason; Costa, Giulia; Hjelmar, Ole; Lombardi, Francesco

    2018-03-01

    Several types of standardized laboratory leaching tests have been developed during the past few decades to evaluate the leaching behaviour of waste materials as a function of different parameters, such as the pH of the eluate and the liquid to solid ratio. However, the link between the results of these tests and leaching data collected from the field (e.g. in disposal or reuse scenarios) is not always straightforward. In this work, we compare data obtained from an on-going large scale field trial, in which municipal solid waste incineration bottom ash is being tested as road sub-base material, with the results obtained from percolation column and pH-dependence laboratory leaching tests carried out on the bottom ash at the beginning of the test. The comparisons reported in this paper show that for soluble substances (e.g. Cl, K and SO 4 ), percolation column tests can provide a good indication of the release expected in the field with deviations usually within a factor of 3. For metals characterized by a solubility-controlled release, i.e. that depends more on eluate pH than the liquid to solid ratio applied, the results of pH-dependence tests describe more accurately the eluate concentration trends observed in the field with deviations that in most cases (around 80%) are within one order of magnitude (see e.g. Al and Cd). The differences between field and lab-scale data might be in part ascribed to the occurrence in the field of weathering reactions (e.g. carbonation) but also to microbial decomposition of organic matter that modifying leachate pH affect the solubility of several constituents (e.g. Ca, Ba and Cr). Besides, weathering reactions can result in enhanced adsorption of fulvic acids to iron/aluminum (hydr)oxides, leading to a decrease in the leaching of fulvic acids and hence of elements such as Cu, Ni and Pb that strongly depend on DOC leaching. Overall, this comparison shows that percolation column tests and pH-dependence tests can represent a reliable

  4. Insights into the Hydrothermal Stability of Triamine-Functionalized SBA-15 Silica for CO2 Adsorption.

    Science.gov (United States)

    Jahandar Lashaki, Masoud; Ziaei-Azad, Hessam; Sayari, Abdelhamid

    2017-10-23

    The hydrothermal stability of triamine-grafted, large-pore SBA-15 CO 2 adsorbents was studied by using steam stripping. Following two 3 h cycles of steam regeneration, lower CO 2 uptakes, lower CO 2 /N ratios, and slower adsorption kinetics were observed relative to fresh samples, particularly at the lowest adsorption temperature (25 °C). CO 2 adsorption measurements for a selected sample exposed to 48 h of steam stripping depicted that after the initial loss during the first exposure to steam (3-6 h), the adsorptive properties stabilized. For higher adsorption temperatures (i.e., 50 and 75 °C), however, all adsorptive properties remained almost unchanged after steaming, indicating the significance of diffusional limitations. Thermogravimetric analysis and FTIR spectroscopy on grafted samples before and after steam stripping showed no amine leaching and no change in the chemical nature of the amine groups, respectively. Also, a six-cycle CO 2 adsorption/desorption experiment under dry conditions showed no thermal degradation. However, N 2 adsorption measurement at 77 K showed significant reductions in the BET surface area of the grafted samples following steaming. Based on the pore size distribution of calcined, grafted samples before and after steaming, it is proposed that exposure to steam restructured the grafted materials, causing mass transfer resistance. It is inferred that triamine-grafted, large-pore SBA-15 adsorbents are potential candidates for CO 2 capture at relatively high temperatures (50-75 °C; for example, flue gas) combined with steam regeneration. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Effects of Pregnant Leach Solution Temperature on the Permeability of Gravelly Drainage Layer of Heap Leaching Structures

    Directory of Open Access Journals (Sweden)

    mehdi amini

    2013-12-01

    Full Text Available In copper heap leaching structures, the ore is leached by an acidic solution. After dissolving the ore mineral, the heap is drained off in the acidic solution using a drainage system (consisting of a network of perforated polyethylene pipes and gravelly drainage layers and is, then, transferred to the leaching plant for copper extraction where the copper is extracted and the remaining solution is dripped over the ore heap for re-leaching. In this process, the reaction between the acidic solution and copper oxide ore is exothermal and the pregnant leach solution (PLS, which is drained off the leaching heap, has a higher temperature than the dripped acidic solution. The PLS temperature variations cause some changes in the viscosity and density which affect the gravelly drainage layer's permeability. In this research, a special permeability measuring system was devised for determining the effects of the PLS temperature variations on the permeability coefficient of the gravelly drainage layer of heap leaching structures. The system, consisting of a thermal acid resistant element and a thermocouple, controls the PLS temperature, which helps measure the permeability coefficient of the gravelly drainage layer. The PLS and gravelly drainage layer of Sarcheshmeh copper mine heap leaching structure No. 1 were used in this study. The permeability coefficient of the gravelly soil was measured against the PLS and pure water at temperatures varying between 3°C to 60°C. Also, the viscosity and density of the PLS and pure water were measured at these temperatures and, using existing theoretical relations, the permeability coefficient of the gravel was computed. A comparison between the experimental and theoretical results revealed a good conformity between the two sets of results. Finally, a case (Taft heap leaching structure, Yazd, Iran was studied and its gravelly drainage layer was designed based on the results of the present research.

  6. Kinetics of acid leaching of ilmenite decomposed by KOH part 1: decomposition by KOH and leaching by HCl

    International Nuclear Information System (INIS)

    Nayl, A.A; Aly, H.F.

    2010-01-01

    Decomposition of ilmenite by KOH solutions, to convert titanium to potassium titanate, was first studied . This was followed by leaching titanium from the ilmenite paste using HCl solutions in the temperature range 50-150 degree C for different periods up to 3 hr. The significant factors affecting the leaching process were studied. The experimental data of the decomposition rate of ilmenite by KOH and of the formed KOH paste by HCl under the relevant operating variables were interpreted with the shrinking core model under chemically controlled process. The apparent activation energy for leaching of titanium in both cases bas been evaluated and discussed.

  7. Study on solubility and leaching property of Iodine-129 waste-forms for geological disposal. Document prepared by other institute, based on the trust contract

    Energy Technology Data Exchange (ETDEWEB)

    Sakashita, A.; Izumi, J. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan); Kitao, H. [Nuclear Development Corp., Tokai, Ibaraki (Japan); Ueta, S.; Okada, K.; Nakazawa, T.; Muroi, M. [Mitsubishi Materials Corp., Tokyo (Japan)

    2002-02-01

    As concern the study on the property of Iodine-129 waste-forms, the solubilities and leachabilities of iodine-sodalite and leachabilities of apatite containing Iodine were measured last year. The results in this year are summarized as follows. 1. Solubility and Leachability of Iodine-sodalite. Leachabilities and solubilities of the synthesized iodine-sodalite by HIP method were measured by means of a long-term leach test in the solution with chloride ions and high pH (12.5). The measured solubilities were within a range of 10{sup -3} - 10{sup -2} mol/L, which were larger compare with the previous values. The leachabilities were 10{sup -6} g/cm{sup 2}/day (powder) and 10{sup -3} g/cm{sup 2}/day (block). After the leach test, the solid phases were analyzed and the alternation was not observed. 2. Leaching Property of Apatite Sample which contains Iodine adsorption medicine. Apatite sample was manufactured from apatite and zeorait which adsorbs iodine matrix by plasma-hotpress. The porosity of the samples was under 5% and release rate of iodine was about 10% at plasma-hotpress manufacturing. The leachabilities of iodine were 10{sup -4} - 10{sup -3} g/cm{sup 2}/d at 56 day soaking period. These values were 1 - 2 digits higher compare with the leachabilities of calcium. It is thought that the iodine selectively is leached from apatite sample. (author)

  8. Impacts of climate and management on water balance and nitrogen leaching from montane grassland soils of S-Germany.

    Science.gov (United States)

    Fu, Jin; Gasche, Rainer; Wang, Na; Lu, Haiyan; Butterbach-Bahl, Klaus; Kiese, Ralf

    2017-10-01

    In this study water balance components as well as nitrogen and dissolved organic carbon leaching were quantified by means of large weighable grassland lysimeters at three sites (860, 770 and 600 m a.s.l.) for both intensive and extensive management. Our results show that at E600, the site with highest air temperature (8.6 °C) and lowest precipitation (981.9 mm), evapotranspiration losses were 100.7 mm higher as at the site (E860) with lowest mean annual air temperature (6.5 °C) and highest precipitation (1359.3 mm). Seepage water formation was substantially lower at E600 (-440.9 mm) as compared to E860. Compared to climate, impacts of management on water balance components were negligible. However, intensive management significantly increased total nitrogen leaching rates across sites as compared to extensive management from 2.6 kg N ha -1 year -1 (range: 0.5-6.0 kg N ha -1 year -1 ) to 4.8 kg N ha -1 year -1 (range: 0.9-12.9 kg N ha -1 year -1 ). N leaching losses were dominated by nitrate (64.7%) and less by ammonium (14.6%) and DON (20.7%). The low rates of N leaching (0.8-6.9% of total applied N) suggest a highly efficient nitrogen uptake by plants as measured by plant total N content at harvest. Moreover, plant uptake was often exceeding slurry application rates, suggesting further supply of N due to soil organic matter decomposition. The low risk of nitrate losses via leaching and surface runoff of cut grassland on non-sandy soils with vigorous grass growth may call for a careful site and region specific re-evaluation of fixed limits of N fertilization rates as defined by e.g. the German Fertilizer Ordinance following requirements set by the European Water Framework and Nitrates Directive. Copyright © 2017. Published by Elsevier Ltd.

  9. Bacterial leaching of pyritic gold ores

    International Nuclear Information System (INIS)

    Gagliardi, F.M.; Cashion, J.D.; Brown, J.; Jay, W.H.

    1998-01-01

    Full text: Pyritic ores (pyrite and arsenopyrite) containing gold concentrations in excess of 50g Au/t can be processed to recover the gold by the removal of the sulphur from the ore. This may be achieved by roasting (producing sulphur dioxide emissions), pressure oxidation (expensive and suitable for large high grade deposits), pressure leaching (still currently being developed) or bacterial oxidation. The bacterial oxidation process is a well known process in nature but has only recently come under investigation as a economically viable and relatively clean method of gold recovery from deep low grade sulphidic ores. Samples were obtained from the Wiluna Gold Mine in Western Australia consisting of the original ore, six successive bacterial reactors and the final products. Moessbauer experiments have been performed at room temperature, liquid nitrogen and liquid helium temperatures, and in applied magnetic fields. The main components of the iron phases which were present during the bacterial treatment were pyrite and arsenopyrite which were readily oxidised by the bacteria. Ferric sulfates and ferric arsenates were identified as by-products of the process with a small amount of the oxyhydroxide goethite. These results are in contrast to the similar study of the Fairview Mine in South Africa where principally Fe(II) species were observed

  10. Bacterial leaching of pyritic gold ores

    Energy Technology Data Exchange (ETDEWEB)

    Gagliardi, F.M.; Cashion, J.D.; Brown, L.J. [Monash Univ., Clayton, VIC (Australia). Dept. of Physics; Jay, W.H. [Monash Univ., Clayton, VIC (Australia). Chemical Engineering Department

    1996-12-31

    The bacterial oxidation process is well known in nature but has only recently come under investigation as a viable and relatively clean method of gold recovery from ores. However there is currently little information about the process at an atomic scale. It is known that the bacterial attack progresses preferentially along grain boundaries which is precisely where the gold has been deposited from aqueous infiltration. Samples have been obtained from the Wiluna mine in Western Australia consisting of the original ore, 2 pre-treatments, and from six successive bacterial reactors. {sup 57}Fe Moessbauer spectra taken at room temperature show only two quadrupole split doublets which can be ascribed to pyrite, FeS{sub 2}, and arsenopyrite, FeAsS. However, the presence of any superparamagnetic oxide or oxyhydroxide species would be expected to give a spectrum very similar to that of pyrite and would be undetectable in small quantities. At a temperature of 5K, a broad magnetically split sextet is observable with a mean hyperfine field of approximately 50T. This field is characteristic of magnetically ordered ferric iron surrounded by an octahedron of oxygens. The intensity and characteristics of this subspectrum alters through the series and interpretations will be given on the oxidation products of the bacterial leaching

  11. Bacterial leaching of pyritic gold ores

    International Nuclear Information System (INIS)

    Gagliardi, F.M.; Cashion, J.D.; Brown, L.J.; Jay, W.H.

    1996-01-01

    The bacterial oxidation process is well known in nature but has only recently come under investigation as a viable and relatively clean method of gold recovery from ores. However there is currently little information about the process at an atomic scale. It is known that the bacterial attack progresses preferentially along grain boundaries which is precisely where the gold has been deposited from aqueous infiltration. Samples have been obtained from the Wiluna mine in Western Australia consisting of the original ore, 2 pre-treatments, and from six successive bacterial reactors. 57 Fe Moessbauer spectra taken at room temperature show only two quadrupole split doublets which can be ascribed to pyrite, FeS 2 , and arsenopyrite, FeAsS. However, the presence of any superparamagnetic oxide or oxyhydroxide species would be expected to give a spectrum very similar to that of pyrite and would be undetectable in small quantities. At a temperature of 5K, a broad magnetically split sextet is observable with a mean hyperfine field of approximately 50T. This field is characteristic of magnetically ordered ferric iron surrounded by an octahedron of oxygens. The intensity and characteristics of this subspectrum alters through the series and interpretations will be given on the oxidation products of the bacterial leaching

  12. Mesophilic leaching of copper sulphide sludge

    Directory of Open Access Journals (Sweden)

    VLADIMIR B. CVETKOVSKI

    2009-02-01

    Full Text Available Copper was precipitated using a sodium sulphide solution as the precipitation agent from an acid solution containing 17 g/l copper and 350 g/l sulphuric acid. The particle size of nearly 1 µm in the sulphide sludge sample was detected by optical microscopy. Based on chemical and X-ray diffraction analyses, covellite was detected as the major sulphide mineral. The batch bioleach amenability test was performed at 32 °C on the Tk31 mine mesophilic mixed culture using a residence time of 28 days. The dissolution of copper sulphide by direct catalytic leaching of the sulphides with bacteria attached to the particles was found to be worthy, although a small quantity of ferrous ions had to be added to raise the activity of the bacteria and the redox potential of the culture medium. Throughout the 22-day period of the bioleach test, copper recovery based on residue analysis indicated a copper extraction of 95 %, with copper concentration in the bioleach solution of 15 g/l. The slope of the straight line tangential to the exponential part of the extraction curve gave a copper solubilisation rate of 1.1 g/l per day. This suggests that a copper extraction of 95 % for the period of bioleach test of 13.6 days may be attained in a three-stage bioreactor system.

  13. Radionuclide Leaching from Organic Ion Exchange Resin

    International Nuclear Information System (INIS)

    Delegard, C.H.; Rinehart, D.E.

    1998-01-01

    Laboratory tests were performed to examine the efficacy of leach treatments for decontaminating organic ion exchange resins (OIER), which have been found in a number of samples retrieved from K East Basin sludge. Based on process records, the OIER found in the K Basins is a mixed-bet strong acid/strong base material marketed as Purolitetrademark NRW-037. Radionuclides sorbed or associated with the OIER can restrict its disposal to the Environmental Restoration Disposal Facility (ERDF). The need for testing to support development of a treatment process for K Basin sludge has been described in Section 4.2 of ''Testing Strategy to Support the Development of K Basins Sludge Treatment Process'' (Flament 1998). To help understand the effects of anticipated OIER elutriation and washing, tests were performed with well-rinsed OIER material from K East Basin floor sludge (sample H-08 BEAD G) and with well-rinsed OIER having approximately 5% added K East canister composite sludge (sample KECOMP). The rinsed resin-bearing material also contained the inorganic ion exchanger Zeolon-900trademark, a zeolite primarily composed of the mineral mordenite. The zeolite was estimated to comprise 27 weight percent of the dry H-08 BEAD G material

  14. Radiotracer investigation in gold leaching tanks.

    Science.gov (United States)

    Dagadu, C P K; Akaho, E H K; Danso, K A; Stegowski, Z; Furman, L

    2012-01-01

    Measurement and analysis of residence time distribution (RTD) is a classical method to investigate performance of chemical reactors. In the present investigation, the radioactive tracer technique was used to measure the RTD of aqueous phase in a series of gold leaching tanks at the Damang gold processing plant in Ghana. The objective of the investigation was to measure the effective volume of each tank and validate the design data after recent process intensification or revamping of the plant. I-131 was used as a radioactive tracer and was instantaneously injected into the feed stream of the first tank and monitored at the outlet of different tanks. Both sampling and online measurement methods were used to monitor the tracer concentration. The results of measurements indicated that both the methods provided identical RTD curves. The mean residence time (MRT) and effective volume of each tank was estimated. The tanks-in-series model with exchange between active and stagnant volume was used and found suitable to describe the flow structure of aqueous phase in the tanks. The estimated effective volume of the tanks and high degree of mixing in tanks could validate the design data and confirmed the expectation of the plant engineer after intensification of the process. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Leaching tests of cemented organic radioactive waste

    International Nuclear Information System (INIS)

    Calabria, Jaqueline A. Almeida; Haucz, Maria Judite A.; Tello, Cledola Cassia O.

    2011-01-01

    The use of radioisotopes in research, medical and industrial activities generates organic liquid radioactive wastes. At Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) are produced organic liquid wastes from different sources, one of these are the solvent extraction activities, whose the waste volume is the largest one. Therefore a research was carried out to treat them. Several techniques to treat organic liquid radioactive wastes have been evaluated, among them incineration, oxidation processes, alkaline hydrolysis, distillation, absorption and cementation. Laboratory experiments were accomplished to establish the most adequate process in order to obtain qualified products for storage and disposal. Absorption followed by cementation was the procedure used in this study, i.e. absorbent substances were added to the organic liquid wastes before mixing with the cement. Initially were defined the absorbers, and evaluated the formulation in relation to the compressive strength of its products. Bentonite from different suppliers (B and G) and vermiculite in two granulometries (M - medium and F - small) were tested. In order to assess the product quality the specimens were submitted to the leaching test according the Standard ISO 6961 and its results were evaluated. Then they were compared with the values established by Standard CNEN NN 6.09 A cceptance criteria for waste products to be disposed , to verify if they meet the requirements for safely storage and disposal. Through this study the best formulations to treat the organic wastes were established. (author)

  16. Role of Adsorption Phenomena in Cubic Tricalcium Aluminate Dissolution.

    Science.gov (United States)

    Myers, Rupert J; Geng, Guoqing; Li, Jiaqi; Rodríguez, Erich D; Ha, Juyoung; Kidkhunthod, Pinit; Sposito, Garrison; Lammers, Laura N; Kirchheim, Ana Paula; Monteiro, Paulo J M

    2017-01-10

    The workability of fresh Portland cement (PC) concrete critically depends on the reaction of the cubic tricalcium aluminate (C 3 A) phase in Ca- and S-rich pH >12 aqueous solution, yet its rate-controlling mechanism is poorly understood. In this article, the role of adsorption phenomena in C 3 A dissolution in aqueous Ca-, S-, and polynaphthalene sulfonate (PNS)-containing solutions is analyzed. The zeta potential and pH results are consistent with the isoelectric point of C 3 A occurring at pH ∼12 and do not show an inversion of its electric double layer potential as a function of S or Ca concentration, and PNS adsorbs onto C 3 A, reducing its zeta potential to negative values at pH >12. The S and Ca K-edge X-ray absorption spectroscopy (XAS) data obtained do not indicate the structural incorporation or specific adsorption of SO 4 2- on the partially dissolved C 3 A solids analyzed. Together with supporting X-ray ptychography and scanning electron microscopy results, a model for C 3 A dissolution inhibition in hydrated PC systems is proposed whereby the formation of an Al-rich leached layer and the complexation of Ca-S ion pairs onto this leached layer provide the key inhibiting effect(s). This model reconciles the results obtained here with the existing literature, including the inhibiting action of macromolecules such as PNS and polyphosphonic acids upon C 3 A dissolution. Therefore, this article advances the understanding of the rate-controlling mechanism in hydrated C 3 A and thus PC systems, which is important to better controlling the workability of fresh PC concrete.

  17. Stability of iron in clays under different leaching conditions

    Czech Academy of Sciences Publication Activity Database

    Doušová, B.; Fuitová, L.; Koloušek, D.; Lhotka, M.; Matys Grygar, Tomáš; Spurná, P.

    2014-01-01

    Roč. 62, 1-2 (2014), s. 145-152 ISSN 0009-8604 Institutional support: RVO:61388980 Keywords : Clays * Iron * Leaching Stability * Structure * Surface Properties Subject RIV: DD - Geochemistry Impact factor: 1.228, year: 2014

  18. Leaching of Nutrient Salts from Fly Ash from Biomass Combustion

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Vu, Duc Thuong; Stenby, Mette

    2005-01-01

    Methods to selectively leach nutrient salts from fly ash, while leaving cadmium un-dissolved were studied. Temperature, pH, water to fly ash ratio are all expected to influence the kinetics and the equilibrium boundaries for this process. Three different leaching methods were investigated....... The first method was a counter current moving bed process in four stages. The ash was kept in filter bags and leached with water that was introduced into the bags at 40-50°C. In the second method, fly ash and water was brought into contact in a partially fluidized bed. The third method was a counter current...... moving bed process with agitation/centrifugation. It was found that a satisfactory leaching of the nutrient salts could be achieved with the third method using only two or three stages, depending on the water to fly ash ratio. It is an advantage to perform the process at temperatures above 50°C...

  19. Implementation Guidance for the Next Generation Leaching Tests

    Science.gov (United States)

    Poster provides an overview of the purpose and utility of this research, highlights of the research to support the Leaching Environmental Assessment Framework (LEAF), application and translation (including data management and analysis software), intended end users, and lessons le...

  20. Leaching behaviour of tritium from a hardened cement paste

    International Nuclear Information System (INIS)

    Matsuzuru, H.; Moriyama, N.; Ito, A.

    1979-01-01

    Leaching of tritium from a hardened cement paste into an aqueous phase has been studied to assess the safety of solidification of the tritiated liquid waste with cement. Leaching tests were carried out in accordance with the method recommended by the International Atomic Energy Agency. The leaching fraction was measured as functions of the waste-cement wt ratio (Wa/C), temperature of leachant and curing time. the tritium leachability of cements follows the order: alumina cement > Portland cement > slag cement. The fraction of tritium leached increases with increasing Wa/C and temperature and decreasing curing period. A deionized water as a leachant gives a slightly higher leachability than the synthetic sea water. The coating of the specimen surface with bitumen reduces the leachability to about 5% of its value for the specimen without coating. (author)

  1. Microwave Pretreatment for Thiourea Leaching for Gold Concentrate

    Directory of Open Access Journals (Sweden)

    Nag-Choul Choi

    2017-10-01

    Full Text Available In this research, we studied the use of microwave pretreatment to enhance the efficiency of Au leaching from gold concentrate. The gold concentrate was pretreated using microwaves with different irradiation time. The sample temperature was increased up to 950 °C by the microwave irradiation. A scanning electron microscope-energy dispersive spectrometer showed the evolution of microcracks and the reduction of sulfur on the mineral surface. X-ray diffraction data also showed the mineral phase shift from pyrite to hematite or pyrrhotite. A leaching test was conducted for the microwave-treated and untreated gold concentrates using thiourea. Although the thiourea leaching recovered 80% of Au from the untreated concentrate, from the treated concentration, the Au could be recovered completely. Au leaching efficiency increased as the microwave irradiation time increased, as well as with a higher composition of thiourea.

  2. Complex sulphide-barite ore leaching in ferric chloride solution

    Directory of Open Access Journals (Sweden)

    Miroslav Sokić

    2016-06-01

    Full Text Available The results of research on the leaching process of complex sulphide-barite ore were presented in this paper. The leaching process was carried out in a laboratory autoclave by ferric chloride solution. Considering that those minerals are represented in complex structural-textural relationships, it is not possible to extract lead, zinc and copper minerals from ore by flotation methods. The obtained results confirmed possibility of the ore processing directly, by chemical methods. The effect of temperature, time and oxygen partial pressure on the lead, zinc and copper dissolution was studied. The maximal leaching degree was achieved at 100 °C and amount of 91.5 % for Pb, 96.1 % for Zn and 60.7 % for Cu. Leaching at temperatures above 100 °C is impractical.

  3. Kinetics of molybdenite oxidizing leaching in alkali medium by ozone

    International Nuclear Information System (INIS)

    Medvedev, A.S.; Sokratova, N.B.; Litman, I.V.; Zelikman, A.N.

    1985-01-01

    On the basis of investigation of the process kinetics proposed is a model of oxidizing leaching of molybdenite in alkali medium while ozonization of the solution by ozoneair mixture. A kinetic equation is derived, that describes experimental data satisfactorily

  4. Mass Loss and Nutrient Release through Leaching in Tectona ...

    African Journals Online (AJOL)

    User

    West African Journal of Applied Ecology, vol. 24(1), 2016: 43–58. ... utilization of organic compounds in litter, and also leaching .... Department of Physics and Engineering. Physics ... The analysis was done following the method described by ...

  5. Aluminum chloride restoration of in situ leached uranium ores

    International Nuclear Information System (INIS)

    Grant, D.C.; Burgman, M.A.

    1982-01-01

    During in situ uranium mining using ammonium bicarbonate lixiviant, the ammonium exchanges with cations on the ore's clay. After mining is complete, the ammonium may desorb into post-leach ground water. For the particular ore studied, other chemicals (i.e., uranium and selenium) which are mobilized during the leach process, have also been found in the post-leach ground water. Laboratory column tests, used to simulate the leaching process, have shown that aluminum chloride can rapidly remove ammonium from the ore and thus greatly reduce the subsequent ammonium leakage level into ground water. The aluminum chloride has also been found to reduce the leakage levels of uranium and selenium. In addition, the aluminum chloride treatment produces a rapid improvement in permeability

  6. Estimating runoff from ungauged catchments for reservoir water ...

    African Journals Online (AJOL)

    The Lower Middle Zambezi Basin is sandwiched between three hydropower ... This study applied a rainfall-runoff model (HEC-HMS) and GIS techniques to ... Missing data were generated using the mean value infilling method. ... A hydrological model, HEC- HMS, was used to simulate runoff from the ungauged catchments.

  7. Herbicide volatilization trumps runoff losses, a multi-year investigation

    Science.gov (United States)

    Surface runoff and volatilization are two processes critical to herbicide off-site transport. To determine the relevance of these off-site transport mechanisms, runoff and turbulent vapor fluxes were simultaneously monitored on the same site for eight years. Site location, herbicide formulations, ...

  8. Variation of runoff source areas under different soil wetness ...

    African Journals Online (AJOL)

    Runoff source areas can serve as focus areas for water quality monitoring and catchment management. In this study, a conceptual form of the Soil Conservation Service Curve Number method (SCS-CN) is used to define variable-source runoff areas in a meso-scale catchment in the Zagros mountain region, southwest of ...

  9. Quantifying rainfall-runoff relationships on the Mieso Hypo Calcic ...

    African Journals Online (AJOL)

    The mean annual rainfall at Mieso is 738 mm. The soil is a Hypo Calcic Vertisol with a high clay and silt content and is very susceptible to crusting. To achieve the objective of the study, rainfall-runoff measurements were made during 2003 and 2004 on 2 m x 2 m plots provided with a runoff measuring system, and replicated ...

  10. Geometric dependency of Tibetan lakes on glacial runoff

    NARCIS (Netherlands)

    Phan Hien, V.; Lindenbergh, R.C.; Menenti, M.

    2013-01-01

    The Tibetan Plateau is an essential source of water for Southeast Asia. The runoff from its ~34 000 glaciers, which occupy an area of ~50 000 km2, feeds Tibetan lakes and major Asian rivers like the Indus and Brahmaputra. Reported glacial shrinkage likely has an impact on the runoff. Unfortunately,

  11. Cropland filter strip removal of cattle manure constituents in runoff

    Science.gov (United States)

    There is little scientifically-derived information available to help identify setback distances required to effectively reduce contaminants from incoming runoff on cropland areas. The objective of this study was to determine the effects of cropland filter strip (CFS) length and runoff rate on concen...

  12. Modelling surface run-off and trends analysis over India

    Indian Academy of Sciences (India)

    exponential model was developed between the rainfall and the run-off that predicted the run-off with an R2 of ... precipitation and other climate parameters is well documented ...... Sen P K 1968 Estimates of the regression coefficient based.

  13. An Overview of Rainfall-Runoff Model Types

    Science.gov (United States)

    This report explores rainfall-runoff models, their generation methods, and the categories under which they fall. Runoff plays an important role in the hydrological cycle by returning excess precipitation to the oceans and controlling how much water flows into stream systems. Mode...

  14. Factors affecting the runoff response of watersheds to precipitation

    OpenAIRE

    DROZDOVÁ, Martina

    2013-01-01

    This bachelor thesis is focused on the factors that affect the drainage basin of the response. It contains a literature review, which deals with the hydrological cycle characteristics of precipitation, surface runoff and flood and erosion protection. The aim of the work is to evaluate the factors that adversely affect the runoff from the catchment.

  15. Does runoff or temperature control chemical weathering rates?

    International Nuclear Information System (INIS)

    Eiriksdottir, Eydis Salome; Gislason, Sigurdur Reynir; Oelkers, Eric H.

    2011-01-01

    Highlights: → The rate chemical weathering is affected by both temperature and runoff. Separating out these two factors is challenging because runoff tends to increase with increasing temperature. → In this study, natural river water samples collected on basaltic catchments over a five year period are used together with experimentally derived dissolution rate model for basaltic glass to pull apart the effects of runoff and temperature. → This study shows that the rate of chemical denudation is controlled by both temperature and runoff, but is dominated by runoff. - Abstract: The rate of chemical denudation is controlled by both temperature and runoff. The relative role of these two factors in the rivers of NE Iceland is determined through the rigorous analysis of their water chemistry over a 5-a period. River catchments are taken to be analogous to laboratory flow reactors; like the fluid in flow reactors, the loss of each dissolved element in river water is the sum of that of the original rainwater plus that added from kinetically controlled dissolution and precipitation reactions. Consideration of the laboratory determined dissolution rate behaviour of basalts and measured water chemistry indicates that the maximum effect of changing temperature on chemical denudation in the NE Icelandic rivers was 5-25% of the total change, whereas that of runoff was 75-95%. The bulk of the increased denudation rates with runoff appear to stem from an increase in reactive surface area for chemical weathering of catchment solids.

  16. Influence of storm characteristics on soil erosion and storm runoff

    Science.gov (United States)

    Johnny M. III Grace

    2008-01-01

    Unpaved forest roads can be major sources of sediment from forested watersheds. Storm runoff from forest roads are a concern due to their potential delivery of sediments and nutrients to stream systems resulting in degraded water quality. The volume and sediment concentrations of stormwater runoff emanating from forest roads can be greatly influenced by storm...

  17. Control of fjordic deep water renewal by runoff modification

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, A; Edelsten, D J

    1976-09-01

    Loch Etive is a Scottish fjord subject to fresh-water run off which renders it markedly brackish. This paper considers the frequency of deep water renewal, developing a model which relates the timing of all such renewals to runoff records. Using the model one can examine the effect of changes caused by interference with the natural runoff pattern.

  18. Chemical leaching of rapidly solidified Al-Si binary alloys

    International Nuclear Information System (INIS)

    Yamauchi, I.; Takahara, K.; Tanaka, T.; Matsubara, K.

    2005-01-01

    Various particulate precursors of Al 100-x Si x (x = 5-12) alloys were prepared by a rapid solidification process. The rapidly solidified structures of the precursors were examined by XRD, DSC and SEM. Most of Si atoms were dissolved into the α-Al(fcc) phase by rapid solidification though the solubility of Si in the α-Al phase is negligibly small in conventional solidification. In the case of 5 at.% Si alloy, a single α-Al phase was only formed. The amount of the primary Si phase increased with increase of Si content for the alloys beyond 8 at.% Si. Rapid solidification was effective to form super-saturated α-Al precursors. These precursors were chemically leached by using a basic solution (NaOH) or a hydrochloric acid (HCl) solution. All Al atoms were removed by a HCl solution as well as a NaOH solution. Granules of the Si phase were newly formed during leaching. The specific surface area was about 50-70 m 2 /g independent of Si content. The leaching behavior in both solutions was slightly different. In the case of a NaOH solution, the shape of the precursor often degenerated after leaching. On the other hand, it was retained after leaching by a HCl solution. Fine Si particles precipitated in the α-Al phase by annealing of as-rapidly solidified precursors at 773 K for 7.2 x 10 3 s. In this case, it was difficult to obtain any products by NaOH leaching, but a few of Si particles were obtained by HCl leaching. Precipitated Si particles were dissolved by the NaOH solution. The X-ray diffraction patterns of leached specimens showed broad lines of the Si phase and its lattice constant was slightly larger than that of the pure Si phase. The microstructures of the leached specimens were examined by transmission electron microscopy. It showed that the leached specimens had a skeletal structure composed of slightly elongated particles of the Si phase and quite fine pores. The particle size was about 30-50 nm. It was of comparable order with that evaluated by Scherer

  19. Leaching studies of low-level radioactive waste forms

    International Nuclear Information System (INIS)

    Dayal, R.; Arora, H.; Milian, L.; Clinton, J.

    1985-01-01

    A research program has been underway at the Brookhaven National Laboratory to investigate the release of radionuclides from low-level waste forms under laboratory conditions. This paper describes the leaching behavior of Cs-137 from two major low-level waste streams, that is, ion exchange bead resin and boric acid concentrate, solidified in Portland cement. The resultant leach data are employed to evaluate and predict the release behavior of Cs-137 from low-level waste forms under field burial conditions

  20. Process for the in-situ leaching of uranium

    International Nuclear Information System (INIS)

    Habib, E.T.; Vogt, T.C.

    1982-01-01

    Process for the in-situ leaching of uranium employing an alkaline lixiviant and an alkali metal or alkaline earth metal hypochlorite as an oxidizing agent. The use of the hypochlorite oxidant results in significantly higher uranium recoveries and leaching rates than those attained by the use of conventional oxidants. The invention is particularly suitable for use in subterranean deposits in which the uranium mineral is associated with carbonaceous material which retards access to the uranium by the lixiviant