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ABSTRACT: Some geotechnical studies of waste landfills in Portugal were used in order to address several questions concerning the best geological formation for their foundation. The geotechnical features which were adopted in the selection and classification of the chosen sites are discussed. As it is difficult to find thick clayey layers, a region where the geological structure is composed of medium thick layers, alternately clayey and sandy, was proposed. The results of some tests on migration of contaminants which were performed at the foundation of a waste landfill are presented. Monitoring programmes are recommended in order to obtain more quantitative information for further studies and for a more suitable design of waste landfills. INTRODUCTION For many years, in Portugal, urban waste was collected by the municipalities and was deposited on fields without previous analysis of the site suitability or of the pollution effect on the environment. In general, the selection of those waste deposit sites was merely based upon the commercial value of the site or availability from the owner. Thus, many unsuitable sites were used and the waste deposits polluted the soils and the groundwater as no geotechnical or environmental studies were performed and no engineering designs or practices were used or adopted. In small municipalities the waste was deposited directly over the surface. Thus, during rainy seasons the water swamped the whole area creating a big amount of leachates which were drained in open air conditions along the fields and directly to the water courses. The rivers and streams existing nearby were submitted to an intensive contamination and become hardly polluted. According to most of the environmental criteria, that water become unsuitable to be used for human, animal, agricultural and farming or industrial purposes without a previous treatment.
ABSTRACT: The general report passes in review the 25 papers included in theme T2, grouping them by the most important topic, and presents some comments of a more general nature on different environmental issues. RÉSUMÉ: Le rapport general passe en revue les 25 communications inserees dans le thème T2, en les groupant par le sujet le plus important, et presente quelques commentaires d'une nature plus generale sur de differents problèmes d'environnement. ZUSAMMENFASSUNG: Der Generalbericht betrachtet die 25, im Thema T2 einbegriffenen Beitrage, wobei er sie nach dem wichtigsten Gegenstand zusammenfaβt, und erbringt einige Kommentare allgemeinerer Art ueber verschiedene Umweltfragen. 1 INTRODUCTION: The Organizing Committee of the Eurock '93 Symposium chose the "Influence of the Environment in Rock Engineering" as theme T2 of the Symposium, and included the following 6 subthemes under that heading:-Global environmental effects; -Heat and mass transport in fractured rock; -Contaminant migration; -Waste disposal; -Underground storage of waste, hydrocarbons, and energy; and -Control of vibrations. In the last years, environmental questions have been receiving an ever growing attention in the scientific meetings, and a first question we may therefore ask, is: Are we really facing new problems, or only rediscovering old ones? Obviously, engineering works have always exerted some influence on the respective environment, and, vice versa, the environment has always exerted some influence on the engineering works. However, the number and the size of the major engineering works is increasing steadily, and, so, also the corresponding disturbance of the respective environment. The current environmental problems are, therefore, of a different scale than those mankind has known for long. On the other hand, our knowledge about environmental issues is also increasing steadily. We are, therefore, nowadays aware of many environmental problems which, not long ago, tended to be overseen. Finally, we are currently faced with engineering works for which there is little or no previous experience (e.g. nuclear waste disposal). Here, we are really facing new challenges, also from the environmental point of view. A second question we may ask, relates to the fact that, apparently, there is a greater awareness of the environmental problems in the rich countries: Are the environmental issues restricted to the developed countries? Rich countries, usually, have already built many, and sometimes also very large (and very expensive) engineering works, and, for this reason, have, quite often, greater environmental problems than the poor countries, where the construction of engineering works is delayed by the economic situation. On the other hand, rich countries, usually, have also invested more in developing their knowledge about environmental questions, and, so, their environmental problems are, very often, recognized much earlier. Finally, and due to the reason that the environmental problems, quite often, do not originate any immediate economic loss, the temptation exists, especially in poor countries, to consider them as negligible in face of the, sometimes large, immediate expenses incurred in their solution. Unfortunately, the solution of many environmental issues still tends to be considered a luxury. A total of 25 papers were included in theme T2, and demonstrate the widespread general interest of the rock mechanics community in the environmental issues. The response to the 6 propounded subthemes was, however, very disparate. While some of the subthemes (Global environmental effects, Contaminant migration, and Control of vibrations) had only very few contributions, the other ones (Heat and mass transport in fractured rock, Waste disposal, and Underground storage of waste, hydrocarbons, and energy) clearly depict the current great concern with the problems of the waste disposal and, specially, of the nuclear waste storage.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type (0.95)
- Water & Waste Management > Solid Waste Management (1.00)
- Law > Environmental Law (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Energy > Power Industry > Utilities > Nuclear (0.88)
ABSTRACT: Modern sanitary disposal sites, in contrast with old garbage dumps, are based on the concept of assuring minimum environmental impact. Clay is a material nearly unavoidable in the design of landfill bottom liners. However, if mechanical behaviour of clay in contact with water is rather well known, we have little knowledge about properties of clay permeated with leachate. The influence of leachate on geomechanical properties of clay is examined. Various tests are performed with and without leachate to see clay evolution when in contact with pollutant. Leachates vary from one landfill to another and also evolve with time according to the age of deposits. For this reason, a composed leachate as representative as possible of landfills in general is used. The first tests concern the changes in intrinsic properties of the clay: structure, suction, Atterberg limits, compacity. Mechanical properties of clay are examined too. Geotechnical tests, in saturated conditions, have been performed in laboratory for two temperature (20° and 60° C) and four combinations: clay prepared with water and water used during testing (reference); clay prepared with water and leachate used during testing (real case in landfill); clay prepared with leachate and leachate used during testing (particularly unfavourable case); and, clay prepared with leachate and water used during testing (unreal case to show influence of osmotic phenomena). The paper will overview the first results gained. INTRODUCTION The time of garbage dump seen as a pile of wastes is over. Our concern is to improve the environmental quality of these sites. The aim of the investigation described here is to compare the behaviour of clay - the mechanical properties of which as landfill bottom liner have long been proved - wet by water with that wet by municipal solid waste leachate.
- Water & Waste Management > Solid Waste Management (1.00)
- Energy > Oil & Gas > Upstream (0.87)
ABSTRACT: A correct waste containment philosophy consists of:optimisation of the landfill location, construction of high performance lining and capping systems, optimisation of waste storage, short and long term careful monitoring, and a convenient re-use of the landfill area after closure. The geotechnical engineer has strong skills about all the aforementioned topics but in particular can effectively deal with the design, construction quality control and monitoring of the lining and cover systems, the waste storage and compaction procedure, and the foundation and improving treatments for constructions above waste deposits. Due to the large number of geotechnical aspects involved into the above listed issues, only the following topics will be discussed within the present paper:lining systems for landfill base and sides, covers and vertical cut-off walls. Each of these topics has been developed referring to their background, recent developments and new trends. In particular, the fundamentals of updated design procedures will be illustrated with particular reference to conceptual and practical modelling and assessment of related input parameters. Moreover the main literature references will be provided. At the end of the paper, a section, devoted to containment systems for polluted subsoil and abandoned landfills, has been developed in order to deal with one of the most interesting areas as far as the present progress and future advancements are concerned. 1.0 INTRODUCTION The main steps in the progress of modern solid waste containment systems, within the last decade, can be resumed in a rough chronological order as follows: · recognition of the importance of construction procedures on the field scale performances of compacted clay liners (CCLs) and the consequent set up of guidelines for a correct and effective installation (Daniel, 1989, 1993; Jessberger, 1994a; and Daniel & Koerner, 1995).
- Europe > Italy (1.00)
- North America > Canada > Ontario (0.92)
- Europe > Germany (0.92)
- (4 more...)
- Research Report > New Finding (1.00)
- Research Report > Experimental Study (1.00)
- Overview (0.92)
- Geology > Geological Subdiscipline > Geomechanics (0.92)
- Geology > Mineral > Silicate > Phyllosilicate (0.71)
- Geology > Geological Subdiscipline > Environmental Geology > Hydrogeology (0.45)
Abstract In this research the effects of synthetic and landfill leachates on the behavior of loessial soil were investigated. Two synthetic leachate solutions were prepared in laboratory by using sulfuric acid and sodium hydroxide and landfill leachate was provided from Mashhad landfill in Iran. Collapse tests were performed according to the standard procedure of ASTM D5333. At first, collapse tests were performed in different saturation conditions including saturating with water and saturating with landfill leachate. Then, the loess soils were contaminated by synthetic and landfill leachates solutions at 5, 10 and 15% by weight of the dry soil samples. Collapse tests were performed on contaminated loess soils after 7 days of curing. The results showed that the collapse potential of soils contaminated with acidic synthetic leachate was higher than that of clean soil. On the other hand, with increasing the percentage of alkaline synthetic leachate, the rate of soil collapse decreased slightly. Landfill leachate increased the collapsibility of soil due to its acidity.
- Water & Waste Management > Solid Waste Management (1.00)
- Materials > Chemicals > Commodity Chemicals (0.50)
- Energy > Oil & Gas > Upstream (0.48)