published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Boreholes in the vicinity of a nuclear waste repository must be reliably sealed to prevent rapid migration of radionuclide contaminated water from the vicinity of the repository to the accessible environment. Few data currently exist regarding the effectiveness of borehole sealing. The objective of this research was to assess the performance of borehole seals under laboratory conditions, particularly with regard to varying stress fields. The approach used to evaluate borehole seals was to compare flow through a sealed borehole with flow through intact rock. Granite, basalt, and tuff were tested, using either cement or bentonite as the seal material. The main conclusions reached as a result of the experiments is that currently existing materials are capable of forming high quality seals when placed under laboratory conditions. Variation of triaxial stress state about a borehole does not significantly affect seal performance if the rock is stiffer than the seal material. Temperature/moisture variations (drying) degraded the quality of cement seals significantly. Performance partially recovered upon resaturation. A skillfully sealed borehole may reasonably be expected to be as impermeable as a fractured rock mass (subject to site-specific verification). The influence of relative seal-rock permeabilities provides insight into important seal parameters. A plug one order of magnitude greater in permeability than the rock through which it passes resulted in an increase in flow through the borehole and surrounding rock of only 1 1/2 times as compared to the undisturbed rock. Since a sealed borehole and its surrounding rock are only a small part of the total rock mass, the effect is even less pronounced. One of the simplest ways to decrease flow through a seal-rock system is to increase the length of the seal. Significant remaining questions include field emplacement techniques; field vertification of plug quality; plug performance over long time periods, particularly with respect to temperature/moisture variations and chemical stability; and radionuclide sorption capabilities. Scale effects are also important, as shafts and drifts must be sealed as well as larger diameter boreholes.

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Indien är ett land som växer ekonomiskt samtidigt som problem med hur avfall ska tas omhand fortfarande är i utvecklingsfasen. Studiens fokus ligger på hur avfallshanteringen sköts i staden Bangalore. Utifrån ett svenskt perspektiv på avfallshantering med insamling och behandling har Bangalore undersökts och brister lokaliserats. Förbättringsförslag presenteras utifrån de brister som framkommit och ett fokus har lagts på om svenska avfallslösningar skulle kunna implementeras i Bangalore. Svensk avfallshantering utgör en bra grund för ett funktionellt avfallshanteringssystem och har därför använts som referens vid jämförelser och förbättringsförslag. I Sverige används källsortering vid sortering av avfall för att få en högre grad av återvinningsbarhet. De behandlingssteg som finns ger energi på olika sätt och ytterst lite avfall läggs på deponier. Ett ständigt arbete utförs utifrån avfallstrappans steg. I Bangalore är situationen omvänd och det avfall som lyckas samlas in hamnar till största delen på deponier eller inofficiella dumpningsplatser runt om i staden. I Sverige sköts avfallshanteringen av den formella sektorn medan den i Bangalore till stor del utförs av en informell sektor där privata personer samlar in skräp. En litteraturstudie har gett insikt i vilka problem utvecklingsländer kan ha gällande avfallshantering och även vilka faktorer som spelar in vid verkställandet av ett fungerande system. I projektet gjordes en observationsstudie på plats i Bangalore under två veckors tid. Utifrån observationsstudien kunde mycket av tidigare information kring hur avfallshanteringen går till granskas mer kritiskt och ett mer verklighetstroget resultat framföras. Det saknas ett fungerande system som är heltäckande för hela Bangalore, vilket gör att mycket avfall hamnar direkt på gator eller på övergivna tomter. Detta i sin tur ger upphov till dålig lukt för invånarna och en ohygienisk miljö. De insamlingssystem som finns att tillgå för allmänheten var i övergripande fall otillräckliga. Tre olika faktorer identifierades som hindrar att avfallshanteringen ska kunna fungera. Dessa var politik, den formella och informella sektorn, samt insamlingssystem av avfall. Ett stort hinder inom Bangalore är det bristande politiska intresset att få till en fungerande avfallshantering. Inga stora aktioner eller krafttag tas mot de växande mängder avfall som produceras. Inte heller sker en bra integration mellan de formella avfallsinsamlarna som utgörs av avfallstransporter och avfallsinsamlare versusinofficiella avfallsinsamlare. Då Bangalore saknar ett formellt insamlingssystem ges inte rätta förutsättningar för befolkningen att kunna gå någonstans med sitt avfall. Detta leder till en ökad okunskap om hur avfall bör sorteras för att kunna behandlas på ett lämpligt sätt där föredragsvis energi kan utvinnas. Ett tydligare insamlingssystem behövs om Bangalore ska kunna nå en hållbar utveckling och bromsa de eskalerande miljöproblem som de ställs inför. Någon form av behandling av avfall krävs för att minska mängden avfall som hamnar direkt på deponering. Genom att minska trycket på deponierna finns en potential för att få en hållbar stad. / India is a country that is growing economically while the problems with the waste andit´s treatment are still in the development phase. The study focuses on how the waste ishandled in the city of Bangalore. From a Swedish point of view the waste collection andtreatment have been investigated Bangalore and shortcomings identified. Suggestionsfor improvements are presented from the lack of the waste management and the focushas been on how Swedish solutions could be implemented in Bangalore. In Sweden the sorting of waste at a household level is managed from different fractionsin containers and therefore the waste has a higher degree of recyclability. Theprocessing steps that are providing energy are sufficient leading to very little wastebeing added to landfills. A constant work is done based on the waste hierarchy. InBangalore, the situation is the reverse and the waste collected mostly ends up inlandfills or unofficial dumping sites around the city. In Sweden, waste is handled by theformal sector, while Bangalore is largely dependent on an informal sector whereindividuals collect waste. A literature study has provided insight into the difficulties developing countries mayhave to face regarding waste management and the factors that come into play in theexecution of a functioning system. Within the project, an observational study was madein Bangalore for two weeks. Based on the observational study a lot of previousinformation on how waste is handled could be examined more critically and morerealistic conclusions drawn. The lack of a functioning system for waste collectionthroughout Bangalore results in a lot of waste ending up directly on the streets or onabandoned plots. This in turn gives rise to odors for residents and an unhygienicenvironment. The collection available to the public was in most cases insufficient. Three factors were identified that prevent the waste management from functioning.These were politics, the formal and informal sector, as well as the practical collectionof waste. A major obstacle in Bangalore is the lack of political interest of functioningwaste management. No major action is taken against the growing amounts of wasteproduced. A good integration between the formal waste collectors consisting of thetransport of waste and waste collectors versus informal waste collectors is missing.Bangalore also lacks formal collection systems and the people are not given the rightconditions to be able to go anywhere to get rid of their waste. This leads to increasedignorance about how waste should be sorted for processing appropriately and whereenergy can be recovered. A clearer collection is needed if Bangalore is to achieve sustainable development and tocurb the escalating environmental problems they face. Some form of waste treatment isneeded to reduce the pressure on the city landfill. By doing this there is a change for thecity to be sustainable and green.

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg in partial fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg, 1993 / Superfines of less than 200 micron are generated when mining coal. They have not been successfully beneficiated in the past and are not acceptable to the consumer. A processh as been developed whereby the superfines are beneficiated, briquetted without the use of binders and devolatilised to produce a premium smokeless briquette which will attract a premium price in the export market. [Abbreviated abstract. Open document to view full version] / MT2017