Results 1 - 10 of 2027
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[en] The very low-level waste (VLLW) produced during decommissioning of nuclear facilities can be suitable for disposal in landfill type facilities. Considering the similarities in design, the experience gained in near-surface disposal of radioactive waste in trenches and vaults is relevant to the issue of VLLW disposal in landfills. This paper presents a brief review of internationally reported cases of radionuclide releases from near-surface disposal facilities. Based on this review, the conclusions are made that the following radionuclide release and exposure scenarios should be accounted for in safety assessment of VLLW disposal in landfills: i) leaching from waste to groundwater by atmospheric precipitations; ii) bath-tubing scenario; iii) scenarios caused by extreme meteorological and hydrological events (erosion, flooding, etc.); iv) human intrusion. The gaseous transport deserves attention for a number of relevant radionuclides, such as (C-14, Rn-222, etc.). In addition, the possibility of early degradation of engineered containment structures (soil covers, bottom seals) should be cautiously considered. (author)
[en] Understanding spatial variation of rock and soil is important for capability precision as well as groundwater contamination or geopollution management. In view of waste dump/landfills, geoenvironmental hazards ravaging our land including surface and groundwater contamination, site suitability indexing, spatial distribution and characteristics of underlying rock and soil matter are studied. Rock and soil samples were collected in a systematic grid pattern using simple drill core rig and hand auger. Geostatistical and soil property analyses were conducted on each grid. Groundwater aquifer vulnerability to leachate was studied using depth to water table, recharge (precipitation), aquifer material, topographic slope, impact on vadose zone/vadose zone material and hydraulic conductivity (DRASTIC) and geophysical methods. Human population growth analysis indicates tremendous waste generation. Flash points of waste generation and dumping were noted. Geographical positioning system was used to take record of sampling point coordinates. Using a sufficient dataset, each grid indicative factor is objectively scaled, weighed and assigned a numerical rating according to their relative importance employing site suitability (S) analysis approach in an empirical equation. Results were imported into a geographic information system (GIS) platform to generate thematic maps. The results showed that subsurface rock and soil characteristics are neither spatially nor vertically homogeneously distributed. Thematic maps were generated and further interpolated in the GIS domain to produce a composite waste dump/landfill suitability index map.
[en] Recently, Jordan has introduced the integrated solid waste management (SWM) concept. Collection and sorting, composting, incineration of medical waste and sanitary landfills are starting to be implemented, while recycling, reuse and resource recovery are still in the initial stages. In Jordan, up to 50% of the generated waste goes uncollected, and the waste that is collected is mainly mixed with industrial and medical waste during handling and disposal. The typical method of municipal waste disposal in Jordan is landfill, which is poorly managed and lacks most of the basic engineering and sanitary measures for the collection and treatment of gas and leachate. The inability of the existing waste management systems to cope with the growing waste generation rates has led to significant health and environmental problems in Jordan. The problem represents a measurable threat to public health and environmental quality and requires national attention of the highest priority and urgency. The large influx of refugees, the increase of per capita solid waste (SW) generation rates, the impact of dumping SW in non-engineered landfills, the gaps in current related legislation, as well as the absence of proper practices for SW collection and management are the key challenges making this problem highly complicated for the government bodies responsible for handling and managing SW. Therefore, a fresh view is required. There is a need for action. A new integrated SW management system focusing on the overall SW management cycle (street-cleaning, collection, transfer and transport, treatment and disposal) and supplemented by legal, organisational and institutional recommendations is required to ensure optimum results throughout the Kingdom. The purpose of this thesis is to examine the MSW treatment practices in Jordan in order to submit possible treatment approaches, which could be adopted and implemented locally, for sustainable solid waste management in the future. This PhD was conducted in four phases. The first phase was the evaluation of the current situation of SWM practices in Jordan. In this phase, a comprehensive overview of the current situation of the waste management system in Jordan was undertaken. The second phase was an examination of the possibility of optimising the collection route by implementing a route-solving solution using advanced software, the ArcGIS Network Analyst tool, that can lead to benefits related to substantial cost savings, CO emissions and so forth. To this end, a Geographic Information System (GIS) has been created based on data collection involving GPS tracking (collection route/bin position). Both key performance and key operational costs indicators of the actual state (Scenario S0) were evaluated, and by modifying particular parameters, other scenarios were generated and analysed to identify optimal routes. The third phase was the assessment of the compost produced from source-separated organic materials. The study was conducted to explore the physical and chemical properties of compost made from different segregated bio-waste raw materials. The compost produced was monitored in terms of moisture content, bulk density, pH, EC, total organic carbon, total organic matter, total nitrogen, total phosphorus, total potassium and C/N ratio, heavy metal concentrations and compost respiration. Final product quality was examined and assessed against the quality specifications of the German End of Waste Criteria for bio-waste (BioAbfV) which has been subjected to composting. The fourth phase was the investigation of the potential for refuse-derived fuel (RDF) production and utilisation as an alternative fuel for the Jordanian cement industry by using the biodrying process as a solution for the conditions in Jordan to overcome some of its MSW management problems. During this study, laboratory analysis of RDF samples was carried out, to evaluate the RDF quality and compare it with criteria and limits set by some European countries. The biological drying process of solid waste by aerated windrow composting was used as a method of pre-treatment of mixed MSW prior to landfill, in order to produce high calorific material RDF and recover valuable material from the waste stream. Furthermore, the performance of the biological drying process of solid waste by aerated windrow composting was investigated as a pilot scale experiment carried out in Jordan. In conclusion, the findings indicate that GIS-based optimised scenarios could serve as an efficient management tool for the daily operations of solid waste collection and transportation. From an economic point of view, compared to the current situation, the results show that the proposed scenarios allow significant savings of about 23% in overall operational costs. Moreover, vehicle operating time was seen to decrease by 30%, in addition to other extra benefits related to CO emissions. A good alternative for Jordan is the composting of source-separated organic materials. A high quality compost with acceptable chemical properties (OM, TOC, TKN, total P, total K, heavy metals) and physical properties (bulk density, moisture content, etc.) was produced. The absence of local standards, monitoring systems and the legal barriers prevent the control of the sale and application of the compost produced to end users on agricultural/horticultural land. Overall, the results conclude that an efficient waste treatment system could be achieved with a fairly basic and low-cost MBT concept. This is by utilising the biological drying process to produce a substitute fuel for industrial processes. This would reduce the landfill areas required, as well as reduce the air emissions from the landfill, in particular greenhouse gases. High capital investment is needed to set up an RDF plant. However, return on investment is not guaranteed to treat the designated waste quantity for all cases. Therefore, the success of SWM is based on the partnership and cooperation between different parties involved (politicians, local private sector, public sector and international consultant companies). The selection of the appropriate solution for MSW must be based on many factors, such as the availability of land for disposal, the market for recyclable material and the need for energy production, and taking into account the economic and social aspects, with particular attention to environmental issues.
[en] Within the framework of the research project 4717E03510, a compilation of all radiological models, their scenarios, exposure pathways and parameters on which the clearance in the Radiation Protection Ordinance is based is being made. It was shown that the release values given in the Radiation Protection Ordinance StrlSchV (2017) in columns 5, 6, 7, 9a-d, 10 and 10a are mostly consistent with those in the researched literature. With regard to column 8 of the Radiation Protection Ordinance StrlSchV (2017), the initially observed deviations between the literature values and those in the StrlSchV (2017) could be largely clarified. In a next step, the boundary conditions of the models for the calculation of the clearance values in the StrlSchV (2017) were identified; their origin was researched and described. It turned out that the information regarding the model boundary conditions is plausible to a great extent and that the data is consistent. Based on the aforementioned findings, the essential model parameters of the radiological models for calculating the clearance values were identified, and their range of variation was discussed. The clearance values specified in the current Radiation Protection Ordinance StrlSchV (2018) are based on "generalized" exposure scenarios that represent the wide range of exposure situations. For a selection of nuclides, a probabilistic approach based on parameter distributions was examined for several nuclides in addition to the usual deterministic calculation from the given (realistic and improbable) parameter values. For selected scenarios, further calculations of clearance values were performed using freely available calculation codes. The plausibility of the results was checked by comparative calculations of other organizations (benchmarking). In this context, it was shown that two programs used at GRS could determine the dose coefficients for the analysis of external radiation exposure. A selected program was used to model the water dispersion from a landfill. The comparison of the values calculated with those models used by established companies shows a good agreement for most nuclides. Furthermore, the program system Atmospheric Radionuclide Transport Model (ARTM) for the calculation of the dispersion and deposition of released airborne radioactive substances was used for the first time for the calculation of clearance values. In the "ingestion" scenario, significantly lower release values were calculated with ARTM than in the literature. The Öko-Institut also comes to a similar conclusion in its calculations. In a current literature source, these major differences in the calculations were clarified.
[en] According to the Korea Radioactive Waste Agency’s (KORAD’s) medium and low level radioactive waste management implementation plan, the Domestic 3rd Step Landfill Disposal Facility has planned to accept a total of 104,000 drums (2 trenches) of very low level radioactive waste (VLLW), from the decommissioning site from April 2019 - February 2026 (total budget: 224.6 billion Won). Subsequently, 260,000 drums (5 trenches) will be disposed in a 34,076 m2. Accordingly, KORAD is preparing a waste acceptance criteria (WAC) for this facility. Every disposal facility for VLLW in other countries such as France and Spain, operate their WAC for each VLLW facility with a reasonable application approach, This, paper focuses on analyzing the WAC conditions in VLLW sites in the USA and discusses whether these can be met in domestic VLLW WAC. It also helps in the preparation of WAC for the 3rd Step Landfill Disposal Site in Gyeongju, since the USA has prior experience on decommissioning nuclear waste
[en] The adsorption of heavy metals by sanitary landfill liners represents a measure of protection of surface and groundwaters against contamination by metals, mitigating risks to public health. Hence, this research aimed to identify, from correlations, the influence of physico-chemical properties of soils applied in landfill liners using nickel adsorption parameters. Batch equilibrium tests with initial nickel concentrations of 45 to 1440 mg.L-1 were performed in clayey sand and bentonite clay soil, as well as in mixtures. Nickel adsorption parameters from Freundlich and Langmuir isotherm models were obtained, exhibiting a better adjustment in the Freundlich model based on R-2 and RMSE criteria. Thus, the addition of bentonite clay improved the adsorption to nickel, and the cationic exchange capacity (CEC) was the property that considerably influenced the metal retention in the studied soils. (author)
[en] In the project 4719E03520 "Pilot studies on boundary conditions in backfill mines with regard to a specific release for disposal", investigations were carried out as a basis for assessing whether and under which boundary conditions specifically released substances could in principle be disposed of in underground backfill mines in the salt mountains. This report therefore presents the state of the art in science and technology for backfill mining and the conditions in backfill mines that are relevant to release from a technical point of view. In Germany, the disposal of waste gas cleaning waste for the purpose of backfilling waste in the salt mountains is carried out in twelve so-called underground backfilling mines and in a cavern facility. Information on the backfill mines such as cavity volumes, acceptance conditions and further operational aspects has been compiled for this purpose. The report shows the backfilling techniques used and the properties of the waste and backfill materials. Due to the pollutants they contain (heavy metals, organic pollutants, including dioxins and furans) and, above all, the high proportion of saline, water-soluble constituents, there are only very limited possibilities for the environmentally compatible and permanently safe disposal of these residues, for example by underground backfilling or underground landfilling. For this purpose, the main legal bases have been compiled, which also have to be taken into account in the case of the transfer of specifically released substances. Of particular interest here is the so-called long-term safety certificate according to the Backfilling Ordinance (Vers VersatzV), which shows complete containment for 10,000 years. This would eliminate the groundwater and surface water path, in contrast to a near-surface landfill. A further need for research and development is seen, in particular, in the establishment of radiological exposure models which can be based on the operational procedures outlined in this report for shipments in a backfilling mine. Here, the boundary conditions for the specifically released waste for disposal in near-surface landfills must be transferred to the conditions in an underground mine. The determination of the so-called weather flow in a mine is regarded as essential, since air volume and circulation in a mine is limited in comparison to a landfill at the earth's surface in the free atmosphere. This is an important constraint for atmospheric dispersion models.
[de]Im Vorhaben 4719E03520 „Pilotuntersuchungen zu Randbedingungen in Versatzbergwerken hinsichtlich einer spezifischen Freigabe zur Beseitigung“ erfolgten Untersuchungen als Bewertungsgrundlage, ob und unter welchen Randbedingungen spezifisch freigegebene Stoffe in Untertageversatzbergwerken im Salzgebirge grundsätzlich entsorgt werden könnten. In diesem Bericht wird daher der Stand von Wissenschaft und Technik zum Versatzbergbau und die aus technischer Sicht freigaberelevanten Bedingungen bei Versatzbergwerken dargestellt. In Deutschland erfolgt die Entsorgung u. a. von Abgasreinigungsabfällen zum Zwecke des Versatzes der Abfälle im Salzgebirge in zwölf sog. Untertageversatz-Bergwerken und in einer Kavernenanlage. Hierzu wurden Informationen zu den Versatzbergwerken wie Hohlraumvolumina, Annahmebedingungen und weiteren betrieblichen Aspekten zusammengestellt. Im Bericht werden die eingesetzten Versatztechniken und die Eigenschaften der Abfälle bzw. Versatzstoffe aufgezeigt. Für die umweltgerechte und dauerhaft sichere Entsorgung dieser Rückstände existieren aufgrund der in ihnen enthaltenen Schadstoffe (Schwermetalle, organische Schadstoffe, u. a. Dioxine und Furane) und v. a. aufgrund der enthaltenen hohen Anteile an salzhaltigen, wasserlöslichen Bestandteilen nur sehr eingeschränkte Entsorgungsmöglichkeiten u. a. durch untertägigen Versatz oder untertägige Deponierung. Hierzu wurden die wesentlichen rechtlichen Grundlagen zusammengestellt, die auch bei einer Verbringung von spezifisch freigegebenen Stoffen einzubeziehen sind. Insbesondere von Interesse ist hierbei der sog. Langzeitsicherheitsnachweis nach der Versatzverordnung (VersatzV), der den vollständigen Einschluss für 10.000 Jahre aufzeigt. Somit würden im Unterschied zu einer oberflächennahen Deponie Grundwasser- und Oberflächenwasserpfad entfallen. Ein weiterer Forschungs- und Entwicklungsbedarf wird insbesondere bei der Aufstellung von radiologischen Expositionsmodellen gesehen, die auf den in diesem Bericht skizzierten Betriebsabläufen bei der Verbringung in einem Versatzbergwerk basieren können. Hierbei gilt es die Randbedingungen zu den spezifisch freigegebenen Abfällen zur Beseitigung auf oberflächennahen Deponien auf die Bedingungen in einem untertägigen Bergwerk zu übertragen. Als wesentlich wird hierbei die Bestimmung des sog. Wetterstroms in einem Bergwerk angesehen, da Luftvolumen und -zirkulation in einem Bergwerk, im Vergleich zu einer Deponie an der Erdoberfläche an der freien Atmosphäre, begrenzt ist. Dies ist eine wichtige Randbedingung für atmosphärische Ausbreitungsmodelle.
[en] The objective of this publication is to initiate a reflection about the relationship between energy and circular economy, notably by considering the territorial energy loops. Thus, as circular economy is too often limited to stakes related to the management of material resources, and as only few articles of the law related to the struggle against wastage and to circular economy address energy issues, this publication considers arrangements which merge objectives of circular economy and objectives of energy efficiency. This publication discusses these arrangements, according to three axes: promoting energy savings (necessity to reduce the dependence on energy imports, means to be implemented to promote energy savings and to reduce the energy bill), improving waste energy valorisation (definition of a general objective, development of wood waste energy valorisation, regulation of biological valorisation and bio-waste management, regulation of spreading), and reaching land-filling reduction objectives.
[en] Environmentally friendly municipal solid waste management is the biggest problem facing several developing countries, including Ghana. Heavy metals pollution generated by landfill leachate has become increasingly concerned due to its potential impact on human health. This study assessed the pollution level and sources of heavy metal levels in groundwater, as well as evaluated the human health risk effect. The sampling technique and sample treatment were done based on the Standard Methods for the Examination of Water and Wastewater. The results suggested that the mean concentration of Pb, Fe, Cd, and Cr was above the acceptable limits of the World Health Organization for drinking water except for Zn and Cu. The heavy pollution index indicates contamination, while hazard index values at sites BH1 and W4 were greater than one, suggesting adverse health effects. However, the heavy metal pollution index values were less than the critical limit of 100 for drinking water. Multivariate analysis predicted that lithogenic and anthropogenic factors were the possible sources of water pollution of heavy metal in the Oti community. Thus, multivariate statistical techniques could be a beneficial tool for the evaluation of possible sources of heavy metal contamination. The high levels of heavy metals found in the Oti community suggested a considerable pollution of water by leachate percolation from the landfill site. The findings of the study, which can be used in areas under similar environmental conditions, can offer a valuable benchmark for the design of suitable approaches to manage groundwater resources by both local and national policymakers.
[en] Human population growth, high consumption and unsustainable management of products and services are exceeding the sustainable use of natural resources. The use of disposable diapers, not only baby but also geriatric ones, reaches a high value, increasing considerably the urban solid residue generation. Currently, all this urban solid residue goes to landfills, taking up to 400 years to decompose, as most of its components are derived from oil. Its use as energy source, as it is already done with the cane bagasse, would bring great benefits, such as power generation and waste reduction. The objectives of this work were to identify the composition of each layer of a disposable diaper for babies and estimate the potential energy through combustion, employing the thermal analytical techniques TG/DTG/DTA, aiming at the reduction in the waste disposed in landfills, contributing in this way to an effective solid waste residue management. The layer 1 presented an endothermic peak at 165 °C, suggesting the presence of polypropylene, and layer 2 presented an endothermic peak at 130 °C, possibly consistent presence of polyethylene according to the manufacturer’s information and infrared analyses. Through the DTA curves of layers 4, 5 and sodium polyacrylate (PSA), it is observed that the fusion temperatures of the polymer are around 425 °C indicating the presence of PSA in both layers. The disposable diaper combustion releases approximately 12 kJg−1, lower than the heat released from sugarcane that is around 17 kJg−1; if used to obtain energy would help the removal of the diaper from the environment by reducing space occupied by that residue in landfills, contributing to environmental sustainability.