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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Oxydation de pyrolyse du dibenzofurane à trés faibles concentrations : application à la réduction des émissions de dioxines / Oxidation and pyrolysis of dibenzofuran at very low concentration : Application to the reduction of dioxins emissions

Tritz, Audrey 24 February 2014 (has links)
"Les dioxines" (PCDD/F : polychlorodibenzodioxines/furanes) sont des polluants organiques persistants émis dans l'atmosphère, provenant de combustions incomplètes. Cette étude concerne l'oxydation et la pyrolyse du dibenzofurane (DBF) choisie comme molécule modèle des PCDF. La réaction est étudiée dans un réacteur parfaitement agité entre 500 et 950°C, pour un temps de passage de 3 à 5s et à très faible concentration de DBF (~2 ppm) pour se rapprocher des conditions des incinérateurs (UIOM). Les espèces intermédiaires, formées lors de la décomposition du DBF, sont identifiées par GC/MS puis quantifiées par TD/GC/FID. Ces produits sont des dérivés du benzofurane, des composés aromatiques et poly-aromatiques. A partir de ces résultats, un mécanisme cinétique détaillé a pu être développé et validé. Ce mécanisme est ensuite utilisé pour simuler d'autres conditions opératoires et optimiser la zone de postcombustion des UIOM / "Dioxins" (PCDD/F) are persistent organic pollutants which are emitted in the atmosphere by several combustion and thermal processes. The present study concerns the oxidation and the pyrolysis of dibenzofuran which is chosen as a model molecule of polychrorodibenzofurans. The reaction is studied at very low concentration of dibenzofuran (~2 ppm) in a continuous perfectly stirred reactor between 3s and 5s, whereas temperature is ranging from 500°C to 950°C. During dibenzofuran decomposition, several intermediary species are formed; they are identified by GC/MS and then quantified by TD/GC/FID. The main products are derivatives of benzofuran, polyaromatic hydrocarbons and other volatile organic compounds. Taking into account our experimental results and the literature data, we have proposed and validated a detailed mechanism of DBF reaction. This mechanism is used to model the abatement of dioxins by total oxidation in the postcombustion area of a municipal waste incinerator
72

Polyhydroxyalkanoate Production from Municipal Waste Streams / Polyhydroxialkanoatproduktion från kommunalt avfall

Eriksson, Elsa January 2020 (has links)
Polyhydroxyalkanoates (PHAs) are a group of bioplastics, which are produced through microorganisms. They are accumulated in granules inside bacteria’s cell cytoplasm and serve as an energy reserve. Moreover, PHAs are completely biodegradable and biocompatible biopolyesters, which make them to suitable materials for medical applications and replace conventional petrochemical plastics. However, it is not economically feasible to produce PHAs yet, as it is four to nine times as expensive as to produce fossil fuel-based plastics. In order to reduce the price, it is possible to use waste streams rich in carbon and mixed cultures as microorganisms, which was applied in this thesis work. In this study, PHAs were synthesized from a volatile fatty acid (VFA) mixture rich in hexanoic acid, which was produced by anaerobic digestion of waste streams. To be able to obtain the maximum PHA content, the experimental work was separated into a selection phase and a production phase respectively. During the selection step, enrichment of the mixed culture took place during 50 days altering feast/famine cycles. The production phase was then conducted in a fed-batch cultivation to accumulate as much PHAs as possible, while utilizing the enriched mixed culture.  The selection phase was seen as successful since the quantity of synthesized PHA increased with time. Solely polyhydroxybutyrate (PHB) was formed during this period. The specific consumption rates for the hexanoic acid and acetic acid were almost the same in this phase (0.10 g hexanoic acid/(g volatile suspended soilds (VSS),h) and 0.11 g acetic acid/(g VSS,h)), which suggests that the consumption of these majoritarian fatty acids was simultaneous. However, the determined consumption rate for butyric acid was approximately solely half of the values for hexanoic acid and acetic acid. The highest PHA yield obtained in the enrichment phase was 0.26 g PHB/g VFA.  In the production phase, the highest achieved PHA content was 31.4 % of VSS, which was obtained after five hours. Both PHB and polyhydroxyvalerate (PHV) were formed in this phase, even though the quantity of accumulated PHB dominated with its approximately 97 weight-%. / Polyhydroxialkanoater (PHA:er) är en grupp bioplaster som produceras med hjälp av mikroorganismer. De ackumuleras inuti granulater som finns i bakteriers cellcytoplasma, och används som en energireserv. PHA:er är dessutom fullständigt bionedbrytbara och biokompatibla biopolyestrar, vilket gör dem till lämpliga material att applicera inom medicinska preparat och för att ersätta konventionella petrokemiska plaster. Det är däremot inte ekonomiskt fördelaktigt att producera PHA:er än så länge, då det är fyra till nio gånger dyrare att producera än i jämförelse med att producera plaster från fossila bränslen. Ett tillvägagångssätt för att reducera priset är genom att applicera kolrikt avfall som råmaterial och en blandad kultur av mikroorganismer. Det var detta som tillämpades i detta examensarbete vid PHA produktionen. I denna studie syntetiserades PHA:er från en blandning av flyktiga fettsyror rik på hexansyra, som framställts av avfall genom anaerobisk digestion. Det experimentella arbetet delades in i två faser: en selektionsfas och en produktionsfas. Detta för att kunna erhålla högsta möjliga PHA innehåll. Den blandade kulturen av bakterier berikades under selektionsfasen genom applicering av alternerande svält/frossa cykler i 50 dagar. Produktionsfasen utfördes därefter i en så kallad ”fed-batch odling” för att ackumulera högsta möjliga kvantitet av PHA, med hjälp av den berikade kultur blandningen.  Selektionsfasen ansåg vara lyckad, då mängden ackumulerad PHA ökade med tiden. Endast polyhydroxibutyrat (PHB) producerades under berikelsefasen. De erhållna specifika konsumptionshastigheterna för hexansyra och ättiksyra var i samma storleksordning (0.10 g/(g flyktiga suspenderade ämnen, h) respektive 0.11 g/(g flyktiga suspenderade ämnen, h)), vilket tyder på att förbrukningen av dessa fettsyror skedde samtidigt. Konsumptionshastigheten för butansyra var däremot endast cirka hälften av hastigheterna för hexansyra samt ättiksyra. Det högsta PHA-utbytet beräknades till 0.26 g PHB/g flyktiga fettsyror. Det högsta PHA-innehållet som erhölls i produktionsfasen var 31.4 % av de flyktiga suspenderade ämnena, vilket uppmättes efter fem timmar. Både PHB och polyhydroxivalerat (PHV) bildades under denna fas, även om mängden ackumulerad PHB dominerade med 97 vikt-%. / <p>I och med COVID-19 presenterades examensarbetet via zoom</p> / Carbon Neutral Next Generation Wastewater Treatment Plants
73

Vývoj kvality vody v povodí Mladotického potoka / Water quality development in Mladoticky Brook catchment area

Vacková, Zuzana January 2014 (has links)
Water quality was one of the biggest problems of environment in beginning of 90. of 20th century in the Czech republic. Since 90. the level of water quality was in czech rivers rapidly better. Mainly in big rivers have accomplished great changes. The small rivers haven't notice that rapid changes. The Czech republic, after entrance to the European Union have committed to comply with Directive 91/271/EEC reduce urban waste water and which should have big influence to water quality also in small rivers. During 90. industry technology, agriculture, cleaning technology of waste water etc. reached big development. Therefore the presumption is higher quality of water in the Czech republic since 90. Goal of the thesis is comparison of results from 1999-2000 with results from 2012- 2014 from Mladoticky brook catchment, which is lined up to small river catchments (79,77km2 ). From this comparison there is obvious trend, if conditions of the water quality are really better or not since 90. [33] Since 2012 to 2014 were taken 12 times samples from 11 profiles of water from Mladotice brook catchment and they were consequential chemically analyzed. The samples were evaluated according to ČSN 757221 and compared with results from 1999-2000. From comparison with data 1999-2000 and 2012-2014 was confirmed the...
74

Vliv typu zástavby na množství tříděného komunálního odpadu v Českých Budějovicích / Influence of urban type to quantity of separated household refuse in České Budějovice

KAISEROVÁ, Lenka January 2010 (has links)
This thesis deals with sorting of a municipal waste by a different type of build-up are in the city of České Budějovice. A research was focus on central build-up area and suburban built-up area. This simply means research among family houses and prefabricated houses. For the first part of the research was chosen a territory with a similar quantity of inhabitants. Sorted municipal waste container was observed for a different time periods. The aim of this part was to find differences in: sorted municipal waste amount (plastics, paper, colored glass, colorless glass), inhabitant's behaviour to waste sorting, total possibilities of municipal waste treatment and possibilities for an improvement in municipal waste sorting for suburban build-up area. The second part of the research was based on a questionnaire form leaded to family houses inhabitants and prefabricated houses inhabitants in České Budějovice. There where these types of questions : if inhabitants do the waste sorting, how do they behave while waste sorting, if an offer and a size of sorted waste container is sufficient, what next possibilities in waste sorting would inhabitants appreciate and what do they think about recycling costs and situation in the Czech Republic.
75

Autoflocculating Mixotrophic Algal Consortia Approach to Sustainable Wastewater Treatement

Krupa, D January 2014 (has links) (PDF)
The phenomenon of rapid algal blooms in response to nutrient overloads has been adapted to treat synthetic domestic wastewater. Various algal consortia collected from several eutrophied water bodies were subject to high density algal culture (upto 106-107 cells/mL) and screened for rapid algal growth, pollutant removal, nutrient recovery under mixotrophy and auto-flocculation. When tried in laboratory scale algal ponds, these algal consortia showed growth rates between 0.15 and 1.07 d-1. Results indicate that Chlorella occurred frequently among most consortia although not always the largest in number. While individual algal species varied in growth rates among these consortia, the log phase for most of these algae lasted 4-5 d after which the algal species began to flocculate between day 5-8 at different rates. The flocculation stage lasted between Day 6-8 wherein about 65% cells flocculated during monsoon and over 90% in winter. Although over 90% removal of N and 80% removal of P occurred in this period, the net N and P harvested as flocculated algae ranged from ~30-50% and ~40-70%, respectively. A consortia approach, wherein algal cells auto-flocculate after reaching a high cell density and nutrient removal provides an easy, low energy and sustainable approach to simultaneous wastewater treatment as well as energy and nutrient recovery from domestic wastewaters.
76

Verksamheters ansvar för det egna hushållsavfallet : – Utmanar avfallshierarkin det kommunala avfallsmonopolet? / Businesses' liability for their “household waste” : – Does the waste hierarchy challenge the waste management monopoly?

Öström, Andrea January 2020 (has links)
Begreppet hushållsavfall och därmed jämförligt avfall från annan verksamhet infördes i svensk lagstiftning genom kommunala renhållningslagen (1970:892) på 70-talet. En skyldighet att bortforsla och hantera hushållsavfall och därmed jämförligt avfall från annan verksamhet ålades kommunerna samtidigt som ett förbud för andra att hantera avfallet lagfästes. Dokumentation över visst offentligtansvar för avfallshantering i Sverige finns daterat så långt tillbaka som på 1300-talet. På den tiden var renhållning avfallshanteringens främsta syfte vilken efterhölls på grund av sanitära skäl. Avfallslagstiftningen tjänar fortsatt att motverka nedskräpning, men idag är därutöver syftet med det kommunala avfallsmonopolet och omhändertagandeförbudet, skyddet för människors hälsa och miljön. Hushållsavfall och därmed jämförligt avfall från annan verksamhet vilket omfattas av det kommunala avfallsmonopolet definieras i 15 kap. 3 § miljöbalken (1998:808). Hushållsavfall är ett snävare begrepp än avfall, vilket innebär att avfallet först måste falla under avfallsdefinitionen för att komma i fråga som hushållsavfall. Tolkningen av avfallsdefinitionen har till stor del fastslagits genom EU-domstolens praxis. I Sverige råder sedan 70-talet oklarhet om vilket avfall som omfattas av därmed jämförligt avfall från annan verksamhet i 15 kap. 3 § MB och således omfattas av det kommunala avfallsmonopolet. Konsekvensen är att kommuner och verksamhetsutövare saknar kunskap om sina rättigheter och skyldigheter, vilket i sin tur leder till konflikter mellan verksamheter och kommuner. Eftersom avfall av given anledning inte hanteras på ett optimalt miljömässigt sätt, undergrävs i längden miljöbalkens syfte, att skydda människors hälsa och miljön. Flera områden av avfallshanteringen regleras idag av EU-rättsliga bestämmelser. Avfallshierarkin i artikel 4 Europaparlamentets och rådets direktiv 2008/98/EG av den 19 november 2008 om avfall och om upphävande av vissa direktiv1 (avfallsdirektivet) implementerades i 15 kap. 10 § MB genom SFS 2016:7822. Avfallshierarkin är en av flera viktiga principer i avfallsdirektivet, genom vilken en prioriteringsordning fastställs för vad som allmänt utgör det totalt sett bästa miljöalternativet inom lagstiftning och politik på avfallsområdet. Kommunens avfallsmonopol och avfallsdirektivet har skyddsintresset för hälsa och miljö gemensamt. I uppsatsen visas att svensk rätt sedan 2018 tillämpats i förenlighet med avfallshierarkin. I de fall var verksamheter visat att de hanterar deras avfall jämförligt med hushållsavfall enligt en metod med högre prioritet enligt avfallshierarkin än den kommunen eller dess anlitade entreprenör kunnattillgodose har verksamheterna givits dispens från det kommunala avfallsmonopolet. Något som kan ifrågasättas är att verksamhetsutövare i dagsläget fordras genomgå ett dispensansökningsförfarande för att tillåtas ansvara för det egna hushållsavfallet. För närvarande pågår nationella åtgärder för ytterligare tillnärmning av svensk lagstiftning till avfallsdirektivets syfte och ändamål samtförbättring av genomförandet i svensk rätt.
77

Nakládání s odpadními vodami v obci Sudice / Wastewater management in the village Sudice

Hoferková, Lenka January 2018 (has links)
This thesis is written due to the poor quality of the stream Sudický potok and the fish kills in nearby ponds supplied by the stream. The goal is evaluating the results of the water samples obtained from the four local spots. Polluted quality in the stream in the Sudice town then proceed to design three various solutions of the sewage collection systems. The first option is designing the municipal wastewater treatment plant and the draining wastewater by single sewerage or sanitary sewerage. The second choice designs the domestic waste water treatment plants. The third solution is designing the sanitary sewerage and effluent sewerage to the nearby waste water treatment plant in Šebetov town. All variants are economically evaluated. In conclusion the first solution, municipal waste water treatment plant with the single sewerage, is recommended.
78

Optimalizační modely v odpadovém hospodářství / Optimization models in waste management

Šmídová, Zlata January 2019 (has links)
The master’s thesis deals with the application of optimization models in the waste management. The analysis of the current state, the estimation of information about the flow of a specific waste, the estimation of the probable processing site and the method of processing is developed by a suitable approach based on sophisticated mathematical methods. The mathematical model, which was created by merging the two already existing models, brings results suitable also for forecasting the state of the waste management. The output is a comprehensive computational tool that was tested on data from the year 2015. The results for mixed municipal waste (catalogue number 20 03 01), bulky waste (catalogue number 20 03 07) and waste with catalogue number 19 08 05, i.e. residual sludge from sewage plants, were processed in MS Excel.
79

Matematické modely v oblasti strategického rozhodování / Mathematical models in strategic decision-making

Khýr, Lukáš January 2020 (has links)
This master thesis deals with various mathematical models, which can be used for designing the location of collection points for various fractions of municipal waste with consideration of walking distance, economic demands and utilization of allocated capacities. Scripts for generating input datasets for applied models from basic input data, which are address points with population and GPS coordinates, is also included in the thesis. The model was implemented in GAMS and the script was written in VBA in Microsoft Excel. Model was used in case study. Results of single and multi-criteria approaches are analyzed and compared.
80

Energetické využití komunálního odpadu / Recovery of Energy from Municipal Wastes

Procházka, Jaroslav January 2011 (has links)
Master’s thesis deal with the design of waste to energy plant of municipal waste. The design of technology is to build the component parts of plant and basic calculation of individual apparatus. Overall technology concists of pretreatment of municipal waste, which is then stored in the bunker. Pretreatment municipal waste is fed into the counterflow rotary kiln. Flue Gates from the kilns are routed through multicyklony in the heat recovery steam generators (HRSG). The multicyklon separates the pollutants. The HRSG generates steam required properties from the feedwater from the heat kontent of gas. Superheated steam is driven to the condensing turbine with extract steam for distrikt rating and for power generation. The flue gas from the HRSG are passed through purification section, in which are separand pollutants the dry method purification. The left heat content of flue gas is used in heat exchanger with twist tube for preheating feed water for the HRSG. The flue gas are fed to the stack.

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