| 1. |
- Al-Taie, Laith, et al.
(författare)
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Hazardous wastes problems in Iraq : a suggestion for an environmental solution
- 2011
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Iraq passed through many destructive wars where the country infrastructures have been destroyed. Consequently, various types of hazardous wastes generated from 1991 and 2003 wars are exposed in different parts of Iraq without any aspect of human and environment considerations. Contaminants are found in the form of contaminated rubble with depleted uranium (DU). Landfill disposal is still an economical and vital solution that should serve between 500-1000 years for confining hazardous wastes like DU. The longevity of a hazardous waste landfill is mainly controlled by clay based liners. There are many factors affecting the performance of clay liners. These factors were discussed in this research. The main requirements of hazardous waste landfills were listed according to USEPA and German regulations. Finally, the main aspects of landfill siting criteria in Iraq were suggested.
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| 2. |
- Al-Taie, Laith, et al.
(författare)
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Hazardous wastes problems in Iraq:a suggestion for an environmental solution
- 2013
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scienpress Ltd. - 1792-9040 .- 1792-9660. ; 3:3, s. 81-91
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Tidskriftsartikel (refereegranskat)abstract
- Iraq passed through many destructive wars where the country infrastructures have been destroyed. Consequently, various types of hazardous wastes generated from 1991 and 2003 wars are exposed in different parts of Iraq without any aspect of human and environment considerations. Contaminants are found in the form of contaminated rubble with depleted uranium (DU). Landfill disposal is still an economical and vital solution that should serve between 300-1000 years for confining hazardous wastes like DU. The longevity of a hazardous waste landfill is mainly controlled by clay based liners. There are many factors affecting the performance of clay liners. These factors were discussed. The main requirements of hazardous waste landfills were listed according to USEPA and German regulations. Finally, the main aspects of landfill siting criteria in Iraq were suggested.
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| 3. |
- Al-Taie, Laith, et al.
(författare)
-
Hydraulic properties of smectite clays from Iraq with special respect to landfills of DU-contaminated waste
- 2011
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Landfills of material contaminated by depleted uranium and other low-level radioactive waste must be isolated from the biosphere for a sufficiently long time. This can be effectively made in desert climate by collecting contaminated waste in suitable areas confined by tight embankments and covering them with very tight clay liners protected from desiccation and erosion by suitably composed filters and coarse rock fill. Examples of design principles and construction are described in the paper. The clay liners are made of air-dry expanding clay that can be found in sufficient quantities in Iraq and that provide very good tightness at low cost. The construction technique is well known from various projects.
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| 4. |
- Al-Taie, Laith, et al.
(författare)
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Hydraulic properties of smectite clays from Iraq with special respect to landfills of DU-contaminated waste
- 2013
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - : Scienpress Ltd. - 1792-9040 .- 1792-9660. ; 3:3, s. 109-125
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Tidskriftsartikel (refereegranskat)abstract
- Landfills of material contaminated by depleted uranium and other low-level radioactive waste must be isolated from the biosphere for a sufficiently long time. This can be effectively made in desert climate by collecting contaminated waste in suitable areas confined by tight embankments and covering them with very tight clay liners protected from desiccation and erosion by suitably composed filters and coarse rock fill. Examples of design principles and construction are described in the paper. The clay liners are made of air-dry expanding clay that can be found in sufficient quantities in Iraq and that provide very good tightness at low cost. The construction technique is well known from various projects.
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| 5. |
- Al-Taie, Laith, et al.
(författare)
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Proposed site selection criteria for hazardous waste disposal facilities in Iraq
- 2012
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Ingår i: Waste Management and the Environment VI. - : WIT Press. - 9781845646066 - 9781845646073 ; , s. 309-319
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Konferensbidrag (refereegranskat)abstract
- Hazardous wastes in Iraq can be considered as a looming crisis due to its severe impact on health and environment after the 1991 and 2003 wars. The most dangerous type is depleted uranium waste. It is classified by EU and USEPA as Low-Level radioactive Waste and a simple and sufficiently safe way of isolating it from the biosphere is to turn it into a landfill confined within tight dikes. Selection of a disposal site requires a number of conditions to be fulfilled, like socio/economic, environmental and geotechnical criteria, which, in combination, determine where such landfills can be located. This is particularly obvious for Iraq, with its large desertic areas that are available for constructing landfills of hazardous waste. The climatic conditions are suitable and the deep groundwater level valuable for minimizing or avoiding contamination of the area. Heavy rain may occasionally fall requiring special measures to be taken for maintaining stability and tightness. This paper lists suitable site selection criteria for landfills of hazardous waste with special respect to Iraq. An example of a suitable disposal site is described and assessed.
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| 6. |
- Al-Taie, Laith, et al.
(författare)
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Hydraulic properties of smectite rich clay controlled by hydraulic gradients and filter types
- 2014
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Ingår i: Applied Clay Science. - : Elsevier BV. - 0169-1317 .- 1872-9053. ; 87, s. 73-80
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Tidskriftsartikel (refereegranskat)abstract
- The common practice in geotechnical laboratories is to apply high hydraulic gradients for getting results in reasonable time but this can jeopardize the accuracy. In this paper, the hydraulic conductivity of a smectite rich clay from Iraq was determined under different hydraulic gradients (5 to 10000 m/m) using several densities and two permeants. Also, two types of filters were used, ordinary stainless steel sintered filter and sand/silt filter, in order to examine the possible effect of clogging by dragged clay gel particles. It was concluded that the outflow filter can affect the evaluated conductivity especially when applying high hydraulic gradients. For sintered filters the hydraulic conductivity was reduced as the gradient increased, while the conductivity increased as the hydraulic gradient increased when using sand/silt filters. For salt water the impact of the gradient was less obvious than for distilled water. A theoretical model was derived for selecting safe hydraulic gradients as a function of dry density, hydraulic gradient, swelling pressure and permeant type. A major conclusion was that the gradient in laboratory testing should not exceed 100 m/m.
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| 7. |
- Al-Taie, Laith, et al.
(författare)
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Natural smectitic soils for protective liners in arid climate
- 2014
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Ingår i: Applied Clay Science. - : Elsevier BV. - 0169-1317 .- 1872-9053. ; 102, s. 104-112
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Tidskriftsartikel (refereegranskat)abstract
- Compacted clay liners (CCL) can be used to isolate hazardous wastes like the soil and military scrap contaminated with depleted uranium that emanated from the Iraqi wars in 1991 and 2003. Near-surface repositories for such dangerous waste can preferably be located in the Iraqi deserts, which make up 60% of the territory of Iraq. CCLs are usually constructed using a mixture of clayey soil and coarse material compacted in air-dry form or suitably wetted. In the present study, two smectitic soils from Iraq, termed Green and Red clays, were investigated for potential use in CCLs. The shear strength, swelling pressure, hydraulic conductivity and creep properties were determined and used for preliminary design of top and bottom liners. The engineering properties were determined for various dry densities and water contents ranging from air-dry to fully saturated conditions. The results showed that mixtures of sand and 30-50% Green clay, and mixtures of sand and 40-60% Red clay are suitable for constructing top liners with a hydraulic conductivity between 1×10-10 - 1×10-9 m/s. For bottom liners, mixtures of sand and 70% Green clay and mixtures of sand and 80% Red clay can be considered. They were found to have a hydraulic conductivity of 1×10-11 m/s for a density at saturation of 2.1 g/cm3 (dry density 1.7 g/cm3). As to the slope stability of top liners, the shear strength for different clay percentages was found to guarantee slope stability for 18o inclination under both air-dry and water saturated conditions.
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| 8. |
- Al-Taie, Laith
(författare)
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Performance of Clay Liners in Near-Surface Repositories in Desert Climate
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wars in Iraq (1991 and 2003) generated various types of hazardous waste (HW) in the form of soil contaminated by depleted uranium (DU). Other HW emanated from destroyed army vehicles and remnants of Iraqi nuclear facilities holding various types and amounts of chemical and radioactive material. The negative impact of the various wastes on the health conditions of the population was reported from different parts of Iraq, showing an enhanced frequency of cancer and abnormally born infants. For isolating the wastes, which represent low-level and short-lived intermediate level radioactive wastes, near-surface repositories (NSR) are proposed since they represent the least expensive way of solving future problems with sufficient safety. Internationally, the timeframe of the containment of such wastes is designated to be 300 years. Site selection affects and largely controls the selection of a suitable design the aim being to minimize or eliminate migration of hazardous elements from the waste to the environment. The formulation of siting criteria is the first vital step toward the resolution of the problem. Site selection criteria are proposed taking in account three major factors: environmental, geological and socio-economic factors. Accordingly, Iraqi deserts, which make up 60% of Iraq, represent the number one candidate for locating a safe disposal facility, primarily because of the low population, suitable topography, climatic conditions, seismic stability and availability of raw materials. Long-term performance of NSR is directly related to the function of top and bottom liner systems. They should be designed so that they are mutually compatible and combine to effectively isolate the waste. Liners are considered as the main elements of any disposal facility on the ground surface and a properly designed top liner system is of particular importance since it will minimize or eliminate water percolation into the waste body. Compacted clay liners (CCL) should preferably have with a low hydraulic conductivity, which is achievable by proper selection of raw materials, compaction density and construction methods. A further criterion is that they must not soften significantly by expansion on wetting, which puts a limit to the smectite content and density. The liners can consist of native material found near the landfill site, and be used after simple processing, primarily drying and crushing, or be mixed with fillers like silty sand. Since the hydraulic conductivity is the key property of a reliable CCL, relevant experimental determination of the hydraulic conductivity is vital. The common practice in geotechnical laboratories is to apply high hydraulic gradients for getting results quickly but this can lead to non-conservative, incorrect results. The present study involved determination of the hydraulic conductivity of a smectite-rich clay sampled at places within reasonable distance from potential NSR sites. Various hydraulic gradients were applied to samples compacted to several different densities, using two permeants and two filter types. It was concluded that the outflow filter can significantly affect the evaluated conductivity especially when applying high hydraulic gradients. This was partly explained by clogging of outflow filters of conventional fine-porous type by torn-off clay particles at such gradients. A major conclusion was that the gradient in laboratory testing should not exceed 100 m/m.In order to assess the suitability of available raw materials within the Iraqi Deserts, two smectitic soils termed as Green and Red clays were investigated for potential use in CCLs. Both clays are fairly rich in smectite, which calls for mixing them with properly graded silt/sand material from the desert for modifying the expandability. The shear strength, swelling pressure, hydraulic conductivity and creep properties were determined and used for defining criteria for selecting suitable clay-sand ratios. The results showed that 30-50% Green clay mixed with sand and 40-60% Red clay mixed with sand were suitable for constructing top liners with a hydraulic conductivity of 1×10-9 - 1×10-10 m/s. For bottom liners, 70% Green clay mixed with sand and 80% Red clay mixed with sand would be suitable; they were found to have a hydraulic conductivity of 1×10-11 m/s.The long-term performance of CCL is controlled by a number of processes like long periods of extreme dryness and short periods of very heavy rain. The percolation of water through the top liner system of a number of design alternatives were simulated using the code HELP 3.95D and subsequently by the FE program VADOSE/W. For the assumed NSR concept the slope stability of the top liner is essential and it was determined by using FE technique considering various slope angles. The engineering properties, primarily the hydraulic conductivity, swelling pressure and shear strength of 30-50% Green clay mixed with sand were introduced in the simulations. Two initial water contents of the compacted materials were considered representing 1) optimum water content (“wet case”), and 2) air‐dry conditions (“dry case”). Application of the HELP code decided the selection of suitable CCL having a thickness of 0.5 m and inclined by 5.7ᵒ. More detailed analyses with VADOSE/W showed that a mixture at the dry case would bring 0.5 mm (0.5 litre of leaking water per square meter) through CCL in an eight year simulation period. Long-term simulations (up to 300 years) showed that CCL would undergo continuous drying without reaching saturation even in the case of periods of very heavy rain (616 mm) for the wet and dry cases. The slope stability factor for the rather steep angle 30ᵒ was found to be 1.5 for the most critical case representing complete water saturation. In conclusion, the proposed materials and design features are believed to be suitable for practical application.
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| 9. |
- Al-Taie, Laith
(författare)
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Performance of landfills of hazardous waste with special respect to the function of clay liners
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This licentiate thesis is based on four papers related to the performance of near-surface low-level (LLW) repositories (landfills) focusing on construction and performance of clay liners in the cappings. The first paper discusses the source of hazardous wastes, their location and their impact on public health. The paper also discusses the scientific basis of the selection of the isolation of such wastes taking in account also cost issues. The paper also shows rules and principles of composing and constructing isolation of such waste according to American and German regulations. The second paper deals with the criteria for locating plants for processing and disposal of hazardous waste in Iraq with special respect to environmental, geological and socio-economic factors. Referring to these criteria a potential disposal site in the Al-Jezira desert is assessed in the paper. The third paper describes the properties of two candidate Iraqi smectitic clays of potential value for isolating hazardous wastes. These clays have been and are still being examined in order to determine their performance and usability for waste isolation. The fourth paper, finally, discusses in detail the hydration-dehydration processes in clay liners in cappings of waste landfills in desertic climates. It also deals with construction issues.
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| 10. |
- Pusch, Roland, et al.
(författare)
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Isolation of hazardous soil contaminated by DU (depleted uranium) from groundwater
- 2012
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Ingår i: Waste Management and the Environment VI. - : WIT Press. - 9781845646066 - 9781845646073 ; , s. 297-308
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Konferensbidrag (refereegranskat)abstract
- Cappings of waste piles conventionally contain a drain layer over a low-permeable clay liner composed of smectite minerals. The rate of percolation of the clay liner, once it has been largely water saturated, determines the downward migration of water into and through the underlying waste. In desert climate, cyclic variation in the degree of hydration of the clay takes place, from desiccated to largely water saturated conditions. Clays of smectite type effectively seal off the underlying waste but the content must be low for preventing contraction and expansion causing a reduced isolation potential of the liner. Penetration of the liner, implying wetting of the waste, starts when the top liner is largely water saturated but the hydration followed by dehydration is confined to take place only to a limited depth according to the assumed wetting mechanism. The rate of wetting usually follows a log time law. For an ideal composition and density of the upper clay liner there will be no percolation and wetting of the underlying waste. The paper is focused on the mechanisms involved in hydration/dehydration of top clay liner prepared by mixing clay and ballast material for providing a basis for design, construction and maintenance of well performing cappings.
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