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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.
1

Procena potencijala remedijacije sedimenta primenom imobilizacionih agenasa / Assessment of potential remediation of metal contaminated sediment using imobilisation agents

Dalmacija Milena 28 June 2010 (has links)
<p>Predmet izučavanja ove disertacije je ispitivanje mogućnosti imobilizacije&nbsp;toksičnih metala u sedimentu primenom imobilizacione tehnike&nbsp;solidifikacije/stabilizacije portland cementom, kalcijum-oksidom, prirodnim zeolitom,&nbsp;letećim pepelom, kaolinitom, montmorilonitom, i različitim sme&scaron;ama ovih agenasa&nbsp;kao i određivanje njihove efikasnosti u zavisnosti od brojnih faktora. Efikasnost&nbsp;imobilizacionih postupaka praćena je kori&scaron;ćenjem tzv. testova izluživanja, odnosno&nbsp;određivanjem koncentracije metala koji su u toku određenog vremena iz imobilisane&nbsp;faze pre&scaron;li u mobilnu fazu gde se smatraju potencijalno opasnim i biodostupnim.&nbsp;Krajnji cilj svakog testa izluživanja je mogućnost procene adekvatnosti primene&nbsp;određene imobilizacione, odnosno remedijacione tehnike. Efikasnost imobilizacionih&nbsp;postupaka zavisi i od određenih osobina: pH rastvora, dodatka imobilizacionog agensa&nbsp;&scaron;to je istraživanjem ispitano. Na osnovu ovog testa, odnosno &nbsp; odnosa kumulativne&nbsp;frakcije metala koja je oslobođena iz imobilizacione sme&scaron;e u mobilnu fazu i vremena&nbsp;određen je tip mehanizma koji omogućava transport metala &nbsp;(spiranje, difuzija,&nbsp;rastvaranje). Takođe su određeni i i parametri (koeficijenti difuzije, indeksi&nbsp;izlužljivosti) koji&nbsp; će poslužiti za ocenu efikasnosti prethodno primenjenih&nbsp;imobilizacionih tehnika. Primenjeni su i modifikovani testovi izluživanja sa ciljem &scaron;to&nbsp;bolje simulacije realnih uslova. U modifikovanim testovima izluživanja kori&scaron;ćen je&nbsp;rastvor sa pH 3,25 da bi se simulirali uslovi koji opona&scaron;aju kisele ki&scaron;e, odnosno uslovi&nbsp;u realnom sistemu. Takođe je kor&scaron;ćen i rastvor huminskih materija sa ciljem&nbsp;simulacije uslova velikog organskog opterećenja do kojeg bi moglo doći u slučaju&nbsp;akcidentnih situacija (na primer poplava) i generalno uslova koji se stvaraju u &nbsp;prirodi&nbsp;pri raspadanju organskog materijala (li&scaron;će, trava, itd.). Rezultati dobijeni simulacijom&nbsp;ovih uslova će dalje omogućiti modelovanje pona&scaron;anja metala u smislu dugoročnog&nbsp;&quot;izluživanja&quot; iz tretiranog sedimenta kao i procenu najefikasnijih agenasa &nbsp; za&nbsp;imobilizaciju različitih metala u sedimentu. Na osnovu dobijenih rezultata, zaključeno&nbsp;je da su optimalni agensi za imobilizaciju metala u sedimentu sme&scaron;a cementa i kreča&nbsp;(5% cementa i 10% kreča), sme&scaron;a montmorilonita i kreča (30% montmorilonita i 10%&nbsp;kreča), leteći pepeo (30%) i zeolit (30%). U ovim sme&scaron;ama dominantan mehanizam&nbsp;izluživanja je difuzija, a ove sme&scaron;e se mogu smatrati inertnim otpadom po svim&nbsp;ispitivanim kriterijumima. Ovi rezultati se mogu upotrebiti za projektovanje i&nbsp;izgradnju pilot postrojenja na kome bi se ispitala efikasnost ovih agenasa za&nbsp;remedijaciju sedimenta u realnim uslovima. Dobijeni podaci su neprocenjivi sa&nbsp;aspekta ekonomski i ekolo&scaron;ki prihvatljivog upravljanja sedimentom.</p> / <p>This work is concerned with exploring the possibilities of immobilization of toxic&nbsp;metals in sediments using solidification/stabilization as imobilization technique and&nbsp;using Portland cement, calcium oxide, natural zeolite, flying ash, kaolinite, montmorilonite, and various mixtures of these agents and determine their&nbsp;effectiveness depending on many factors. Performance of imobilization procedures&nbsp;was followed by the use of so-called leaching tests and determination of the metals&nbsp;concentration that are within a specified interval of time leached from the immobile phase and as such can be considered potentially hazardous and bioavailable. The ultimate goal of every leaching test is to assess the adequacy of the possibility of applying certain imobilization or remediation technique. Performance of imobilizaction procedures depends on certain characteristics: pH of solution, additon of imobilization agent, etc. Based on this test, ie relation between the cumulative fraction of metal leached from imobilization mixture and time, the type of leaching mechanism that allows the transport of metals (wash-off, diffusion, dissolution) was determined. Other parameters which will serve for evaluating the efficiency of the previously applied imobilization techniques (diffusion coefficients, leaching indices) were also determined. Modified leaching tests were applied with the aim of better simulation of real conditions on the field. In the modified leaching tests the solution with pH 3.25 was used to simulate conditions that mimic acid rain and conditions in the real system. The humic acid solution was also used with the aim to simulate high organic loads which could occur in the case accident situation (eg floods) and the general conditions that are created in naturewhen decaying organic material (leaves, grass, etc.). The results obtained by simulating these conditions will enable the modeling of behavior of metals in terms of long-term leaching period from the treated sediment and assess the most effective agents for the immobilization of various metals in the sediments. Based on these results, it was concluded that the optimal agents for immobilization of metals in the sediment mixture of cement and lime (5% cement and 10% lime), a mixture montmorilonite and&nbsp; lime (30% montmorilonite and 10% lime), fly ash (30%) and zeolite (30%). In these mixtures dominant leaching mechanism is diffusion, and these mixtures can be considered as inert waste by all tested criteria. These results can be used to design and builda pilot plant in which order to evaluate the effectiveness of these agents for remediation of sediment in real &nbsp;terms. The obtained data are invaluable from the aspect of economic and ecologically acceptable management of sediment.</p>
2

Co-valorisation de sédiments et de sols fins par apport de liants et de fibres

Liang, Yingjie 29 May 2012 (has links) (PDF)
L'objectif de la thèse est de traiter des sédiments marins et des sols fins équivalents (fines de carrière) considérés comme des déchets, par un procédé de solidification/stabilisation et de les valoriser en matériau pour des sous couches routières. Ces traitements ont donné lieu à des mélanges composites sédiments-liants et/ou ajouts de cendres volantes, de fumée de silice, de produits chimiques réactifs et de fibres suivis d'une analyse comportementale des performances mécaniques et de durabilité. Après avoir sélectionné un panel représentatif de sédiments marins et une fine de carrière, une phase de caractérisation a été entreprise sur les paramètres déterminants en vue de traiter ces sédiments. Elle repose sur l'étude des propriétés physiques (répartition des grains, limites d'Atterberg) et chimiques (la teneur en matière organique et en carbonates). Les différentes caractéristiques, dosages et paramètres dimensionnels des constituants (ciment, chaux, cendre volante, fumée de silice, sables correcteur, produit chimique réactif et fibres naturelle et géosynthétiques) des mélanges sont déterminés. Le programme expérimental complet est présenté, il intéresse les sédiments marins à stabiliser ou solidifier. Les essais mécaniques de résistance et de durabilité (compression simple, traction indirecte, mouillage-séchage) ont été effectués sur échantillons cylindriques. L'analyse et l'interprétation des résultats ont permis de mieux cerner les différents facteurs influant sur la résistance à la compression et à la traction indirecte des mélanges traités avec des additions de liants hydrauliques et de liant pouzzolanique, puis avec des ajouts spécifiques de fumée de silice, de sable correcteur et de produits chimiques réactifs. Une phase innovante a porté sur l'utilisation de fibres déchets dans les mélanges. Ces fibres naturelle (lin) et artificielles (géosynthétiques) ont été proposées pour améliorer le comportement mécanique des mélanges de sédiments marins et/ou fine de carrière. En conclusion, pour les dosages économiques retenus et les mélanges étudiés, une application en sous couche routière est possible (classes S1à S5). La teneur en matière organique des sédiments marins a une forte influence sur l'efficacité des traitements des sédiments marins aux liants. Les renforts fibreux sont tout à fait prometteurs et l'idée de covaloriser deux déchets constitue une avancée dans la gestion durable et la valorisation des sédiments.
3

Elektrokoagulacioni i adsorpcioni tretmani efluenata u grafičkim procesima ofset štampe / Electrocoagulation and Adsorption Treatments of Effluents in Offset Printing Graphic Processes

Adamović Savka 09 September 2016 (has links)
<p>Predmet doktorske disertacije je uklanjanje neorganskih i organskih polutanata iz efluenata ofset tehnike štampe (otpadnog razvijača i otpadnog sredstva za vlaženje) u cilju minimiziranja njihovog štetnog uticaja na životnu sredinu. Uklanjanje polutanata sprovedeno je primenom elektrokoagulaciono/ flotacionog (EKF) tetmana, adsorpcionog (AD) tretmana i kombinacijom navedenih tretmana. Izvodljivost i efikasnost tretmana analizirana je ispitivanjem uticaja karakterističnih operativnih promenljivih u okviru procesa na smanjivanje količine polutanata. Mehanizmi EKF i AD tretmana definisani su na osnovu teorijskih matematičko kinetičkih modela. Za rešavanje problema odlaganja mulja nastalog nakon EKF tretmana primenjen je solidifikaciono/stabiliza-cioni tretman sa odgovarajućim imobilizacionim agensima. Razvijen je efikasan model kombinacije tretmana efluenata grafičkih procesa ofset štampe kojim je omogućena konverzija efluenata u proizvode kompatibilne sa principima i normativima životne sredine.</p> / <p>The topic of this doctoral dissertation is the removal of inorganic and organic pollutants from the offset printing effluents (waste developer and waste fountain solution) in order to minimize their damaging influence onto the environment. The removal of the pollutants has been performed by electrocoagulation/flotation (ECF) treatment, adsorption (AD) treatment and the combination of the two said treatments. Feasibility and efficacy of the treatments has been analyzed by investigating the effect of characteristic operational variables within the process on the decrease in the quantity of pollutants. The mechanisms of ECF and AD treatments have been defined on the basis of theoretical mathematical-kinetic models. For the solution of the problem of sludge disposal, originating from the ECF treatment, a solidification/stabilization treatment with immobilization agents has been applied. An efficient model that combines the offset printing effluent treatments has been developed, the one which enables the conversion of effluents into products compatible with environmental principles and norms.</p>

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