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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.
271

The study of Waste Management practices within households in Khakhanwa Village, Thulamela Municipality

Mabadahanye, Vhonani 18 May 2017 (has links)
MPH / Department of Public Health / The sanitary state of an area is largely influenced by waste handling practices of the residents and measures in place for safe waste evacuation and disposal. Despite strategies that the municipality and local communities have put in place; namely, collection of wastes in one central spot in some villages, littering of all types of wastes is still on the increase in many rural areas. The focus of this study was on common refuse generated at Khakhanwa Village, different waste management practices and the knowledge of villagers on the impact of poor refuse management. The study was carried out using the quantitative, descriptive methodology. A total population of 312 households participated. Data was collected using a structured questionnaire and ethical aspects were taken into consideration. Data was analysed descriptively using SPSS version 22.0. It is presented using graphs, tables and pie chart. The findings show that the respondents satisfactorily showed understanding of waste management and the impact of poor waste management. Due to lack of waste services, the majority of the residents resort to storing wastes within their homes, burning it and disposing of it in open dumping sites as major waste management practices. The most familiar wastes in Khakhanwa village are decomposable wastes, napkins and plastics. These findings call for strengthened waste services in rural areas and more waste education amongst all villagers. Policies on waste management need to be put in motion. Communities need to be equipped with the knowledge of reducing, reusing and recycling for the purpose of limiting wastes. Finally school curricula should be adjusted such that they inform learners about waste management from early ages.
272

Antibiotiques apportés seuls ou en mélange (antibiotique+antibiotique et antibiotique+métaux) dans des sols agricoles – Devenir et impacts sur les microorganismes du sol et leurs activités / Antibiotics alone or in combination (antibiotic+antibiotic and antibiotic+metals) in agricultural soils - Fate and impacts on soil microorganisms and their activities

Andriamalala, Aurore 10 December 2018 (has links)
Les antibiotiques (ATB) consommés en médecine humaine et vétérinaire sont en grande partie excrétés et peuvent entrer dans les sols agricoles via l’épandage des produits résiduaires organiques (PRO), avec des risques encore mal connus sur la santé humaine et l’environnement. De plus, ces ATB sont le plus souvent apportés en mélange avec d'autres contaminants organiques et/ou minéraux. Or très peu d’études ont abordé le devenir et les effets des ATB en interaction avec d'autres contaminants dans les sols.L’objectif de la thèse était donc de mieux comprendre le devenir des ATB, apportés seuls, ou en mélange et leurs impacts sur les microorganismes du sol et leurs activités.Les antibiotiques sélectionnés ont été le sulfaméthoxazole (SMX) et la ciprofloxacine (CIP), pour leur comportement dans le sol et leur mode d’action contrastés, ainsi que le N-ac-SMX, métabolite principal du SMX. Les métaux choisis ont été le cuivre et le zinc car leur accumulation dans le sol est connue pour être favorisée via certains PRO. Ils ont été apportés en mélange, à une dose environnementale, et à une dose 5 fois plus élevée. Les sols sont un sol témoin qui n'a jamais reçu de PRO et deux sols amendés depuis 1998, par du fumier ou un compost de déchets verts et boues de station d’épuration, afin de tester l'impact d'apports répétés de PRO et la nature du PRO.Des microcosmes ont été incubés en conditions contrôlées pendant 156 jours. Pour l'étude du devenir des ATB, les sols ont été traités avec des ATB marqués au 14C et la distribution du 14C a été suivie dans les fractions minéralisées, facilement et difficilement extractibles et non extractibles. L'étude de l'impact des ATB seuls ou en mélange sur les microorganismes et leurs activités a été réalisée à partir d'ATB non marqués.Le devenir des ATB est contrôlé par :i) La nature et les propriétés des ATB : la CIP s'adsorbe rapidement et fortement dans les sols et n'est pas minéralisée. Les sulfonamides sont rapidement dégradés et minéralisés jusqu'à 10% après 156 jours.Les devenirs du SMX et du N-ac-SMX, sont quasiment similaires lorsqu'ils sont apportés seuls, le N-ac-SMX étant transformé en SMX. Quelles que soient les molécules, les résidus non extractibles sont majoritaires en fin d'incubation (> 50%).ii) L'apport répété de PRO qui favorise l'adsorption des ATB et diminuent leur minéralisation.iii) La nature des PRO suivant leur stabilité : le compost, plus stable, favorise la production de résidus difficilement extractibles, le fumier, plus dégradable, stimule la minéralisation des sulfonamides et la production de résidus non extractibles.iv) La présence d'autres contaminants, leur nature et leur concentration : si l'apport de CIP à dose environnementale n'a pas impacté le devenir du SMX et du N-ac-SMX dans les sols, les métaux ont exercé des effets d'autant plus importants que leur dose était élevée. A dose faible, les métaux diminuent la minéralisation du SMX et du N-ac-SMX d'un facteur 2 en favorisant l'adsorption des ATB par complexation en particulier avec le cuivre. A forte dose, les métaux inhibent la minéralisation des sulfonamides avec des effets d'origine physico-chimique (augmentation de l'adsorption des ATB via le cuivre) et certainement biologique (effets toxiques en particulier du zinc).Les sulfonamides n'ont pas eu d'effet sur les microorganismes du sol et la minéralisation du carbone et de l'azote lorsqu'ils sont apportés seuls ou en mélange avec de la ciprofloxacine ou avec des métaux à dose environnementale. En revanche, les mélanges avec la forte dose de métaux exercent des effets toxiques sur la biomasse microbienne et sur la minéralisation du carbone. Ces effets toxiques semblent essentiellement dus aux métaux et non au pH ou à la force ionique.Dans ces conditions expérimentales, les risques environnementaux liés aux ATB semblent donc limités à court terme. Mais il serait nécessaire d’étudier les effets à plus long terme, et les effets d'apports cumulatifs. / The antibiotics (ATB) used in human and veterinary medicine are largely excreted and can enter agricultural soils through the spreading of organic waste products (OWP), with unassessed risks on human health and the environment. In addition, these ATBs are most often combined with other organic and / or mineral contaminants. However, very few studies have addressed the fate and effects of ATBs interacting with other contaminants in soils.The objective of the thesis was to better understand the fate of ATB applied to soils alone or in combination with other contaminants, and their impacts on soil microorganisms and their activities.The antibiotics selected were sulfamethoxazole (SMX) and ciprofloxacin (CIP), for their contrasting mode of action and behavior, and N-ac-SMX, the main metabolite of SMX. The chosen metals were copper and zinc, which are known to increase in soils with regular applications of certain OWPs. They were brought together, at an environmental dose, and at a dose 5 times higher. The soils are a control soil that has never received OWP and two soils amended since 1998, by manure or compost green waste and sewage sludge, to test the impact of repeated applications of OWP and of the nature of OWP.Microcosms were incubated under controlled conditions for 156 days. For the study of ATB fate, the soils were treated with 14C-labeled ATBs and the 14C distribution was followed in the mineralized, easily and hardly extractable and non-extractable fractions. The impact of ATBs alone or in combinations on microorganisms and their activities was studied using unlabelled ATBs.The fate of ATBs is controlled by :i) The nature and properties of ATBs: CIP is rapidly and strongly adsorbed in soils and is not mineralized. Sulfonamides are rapidly degraded and mineralized up to 10% after 156 days.The fates of the SMX and N-ac-SMX are almost similar when they are brought alone, the N-ac-SMX being transformed into SMX. Whatever the molecules, the non-extractable residues are major at the end of incubation (> 50%).ii) Previous repeated applications of OWP that enhance adsorption of ATBs and reduce their mineralization.iii) The nature of the OWP : the more stable compost promotes the production of hardly extractable residues, the manure, more degradable, stimulates the mineralization of the sulfonamides and the production of non-extractable residues.iv) The presence of other contaminants, their nature and concentration : although the CIP at environmental doses did not affect the fate of SMX and N-ac-SMX in soils, the influence of metals was measurable and increased with their dose. At low doses, metals decrease the mineralization of SMX and N-ac-SMX by a factor of 2, by promoting the adsorption of ATBs through complexation, in particular with copper. At high doses, metals inhibit the mineralization of sulfonamides, through physicochemical reactions (increased adsorption of ATBs via copper) and certainly biological effects (toxic effects especially of zinc).The sulfonamides had no effect on soil microorganisms and mineralization of carbon and nitrogen when applied alone or as a mixture with ciprofloxacin or metals at environmental doses. But mixtures with the high dose of metals induce toxic effects on microbial biomass and mineralization of carbon. These toxic effects seem mainly due to metals and not to pH or ionic strength indirect effects.Therefore under these experimental conditions, the environmental risks associated with ATBs seem limited in the short term. But it would be necessary to study the effects in the longer term and of cumulative applications.
273

Waste management strategies employed on construction sites in Gauteng

Sibanda, Desire January 2017 (has links)
Thesis is submitted in partial fulfilment for the degree of Master of Science (Building) in Construction Project Management to the Faculty of Engineering and the Built Environment, School of Construction Economics and Management at the University of the Witwatersrand, Johannesburg, 2017 / There is a problem of construction waste on construction sites. However, there are various strategies that can be employed; not only on construction sites, but generally on construction projects from the inception of the project to manage construction waste more effectively. Construction waste management can loosely be defined as a function of controlling waste on construction projects to limit its generation and disposal but enhance reduce and recycling. Construction waste mainly arises from design changes, poor choice of construction materials, improper material specifications, inappropriate strategies employed or wrong strategies implemented; leading to poor management of waste on construction projects. Construction waste can be ‘physical’ or ‘non-physical’. Physical construction waste refers to tangible solid waste of materials emanating from construction activities. Non-physical waste pertains to waste of time and project funds in the form of unnecessary expenditure. The aim of this study is to identify waste management strategies utilized on construction sites in Gauteng. Pertinent literature provided a basis of the study. A cross-sectional survey using three construction sites in Gauteng: an office building project, a road project and a civil works project was adopted. The most common strategies were found to be –proper selection of construction materials, proper planning and logical sequencing of construction work activities on a project. There is a variety of branded materials hence the need for proper selection of materials. Further, there are a lot of factors that influence the flow of work activities hence the requirement to keep track and plan activities accordingly to counter distortions. It is acknowledged that strategies found to be common in Gauteng are basic techniques in controlling construction waste generation and the results tied back to the literature. It was established that technological tools like Building Information Modeling are not yet common in Gauteng. Improvements on usage of prefabricated components and offsite manufacturing of components is recommended to stakeholders of the construction industry. It is also logical to conclude that waste management strategies employed on construction sites in Gauteng are anchored on factors of economic viability and government policies. In their quest to make projects profitable and in their efforts to make construction projects compliant to regulations, as a result, construction contractors achieve reductions in waste generation on construction projects. Therefore what the study found out are mainly practices that could, in addition to achieving primary aim, contribute to waste reduction. These strategies identified are implemented primarily to achieve time, cost and quality objectives and thus indirectly waste reduction. / MT2018
274

Economic feasibility of processing food waste and incorporating processed food waste products in least cost duck feeds

Budu, Ben Asare. January 2001 (has links)
No description available.
275

Utilization of Pulp and Paper Waste Products in the Metal Industry : Initial testing of carbon-containing waste material briquettes

Johansson, Ingrid, Deltin, Walter January 2018 (has links)
Today, a huge part of waste products from pulp and paper industries ends up in landfill which is both economically and environmentally adversely. This report examines the possibilities of using those products as a slag foamer and fuel in different furnaces in the metal industry. The waste products contain valuable elements, especially carbon. Therefore, there is an increased interest in finding possible use for the waste products in the metal industry. The reuse would contribute to preservation of energy as fossil fuel can be replaced. In the report, two waste materials called mixed biosludge and fiber reject are examined. The experiments are performed with the waste products pressed together with a base material and cement forming a briquette. The requirements examined are strength needed for both transportation and use in furnaces and ability to create a foaming slag. The results in strength were ambiguous, no waste material based briquettes met the set criteria. As of now, the briquettes are probably not strong enough to be transported. No foaming occurred during the experiment, but only one experiment was performed. Therefore, further experiments are needed before any conclusions can be drawn. The briquettes can possibly replace coke and coal in applications where strength is not as important. Nevertheless, it is uncertain if the briquettes affect the steel quality. / Idag läggs en stor del av restprodukter från pappers och massaindustrin på deponi, vilket innebär såväl ekonomiska som miljömässiga nackdelar. Den här rapporten undersöker möjligheterna att använda dessa restprodukter som slaggskummare och bränsle i de olika ugnarna inom metallindustrin. Restprodukterna innehåller värdefulla ämnen, framförallt kol. Därför finns det ett ökat intresse för att hitta möjliga användningsområden för restprodukterna inom metallindustrin. Denna återanvändning skulle bidra till energibevarande eftersom fossila bränslen kan ersättas. I den här rapporten undersöks två restmaterial, blandat biologiskt slam och fiberavfall. Experimenten utfördes med dessa restprodukter pressade samman med ett basmaterial och cement till en brikett. Kraven som undersöks är styrka för både transport och användning i ugnarna samt förmågan att skumma en slagg. Resultaten för briketternas styrka var tvetydiga, inga av briketterna innehållande restprodukter satisfierade det uppsatta kriteriet. Styrkan är troligtvis för låg för att transport ska vara möjlig. Ingen skumning skedde under experimentet, men endast ett experiment genomfördes. Därför behöver ytterligare experiment genomföras innan några slutsatser kan dras. Men briketterna tros kunna ersätta koks och kol där styrkan inte är viktig. Men det är osäkert om briketterna påverkar stålkvaliteten.
276

PAYT de 3éme génération: contributions d'amélioration et de normalisation dans le cadre du coût-vérité des déchets ménagers

Voronine, Valérie 03 December 2014 (has links)
Dans la cadre des « Pay as You Throw » ou système de redevance incitative, le montant payé par chaque ménage est lié à la quantité de déchets émis. Les fonds générés par un système PAYT varient d’un cas à l’autre et ne couvrent pas forcément les coûts réellement engendrés. C’est ce que nous avons dénommé les PAYT de 1ère génération.<p>L’autorité peut décider d’aller plus loin en appliquant une redevance représentant le coût exact de la gestion des déchets. Pour ce, elle doit établir une comptabilité analytique des postes liés à la gestion des déchets. C’est le cas de la Région wallonne qui à travers l’application de son coût vérité des déchets impose une couverture des coûts s’approchant des 100%. Nous appelons ce concept « PAYT de 2ème génération ». <p>La condition préalable est de disposer, dès la mise en place de système PAYT, d’un cadre standard d’expression des coûts. Or, en Région wallonne, le cadre commun a été réduit à une simple énumération de libellés de recettes et dépenses, traduisant des concepts généraux.<p><p>Notre travail propose, d’une part, une normalisation du calcul et le développement d’une méthodologie de comptabilité analytique basée sur les règles de comptabilité budgétaire communale. <p>Parallèlement, l’application du coût-vérité ne donne qu’une image financière de la gestion des déchets des villes et communes. En aucune façon, il ne donne d’information concernant le niveau de service offert, ni le niveau des performances environnementales. Notre travail propose donc, d’autre part, l’ajout d’un calcul des performances environnementales et des services comme piste d’amélioration du système coût-vérité wallon. <p>Nous représentons virtuellement la gestion des déchets par une pyramide reposant sur 3 piliers :le coût, l’environnement et les services, et dont la hauteur représente la quantité produite. Sous le prisme du développement durable de nos villes et communes, la gestion des déchets devrait atteindre un parfait équilibre entre efficacité environnementale, accessibilité économique et acceptabilité sociale en assurant une qualité de vie aujourd’hui et demain pour les générations futures. <p><p>Le coût vérité wallon, déjà PAYT de 2ème génération puisqu’il impose une maîtrise transparente des coûts, deviendrait, en intégrant ces notions de développement durable, PAYT de 3ème génération.<p> / Doctorat en environnement, Orientation gestion de l'environnement / info:eu-repo/semantics/nonPublished
277

Caracterització i revaloració de la fracció plasmàtica de la sang de porc procedent d'escorxadors industrials

Parés i Oliva, Dolors 18 December 1998 (has links)
La tesi s'ha estructurat en tres apartats que, en conjunt, han de permetre determinar les possibilitats d'aprofitament dins la mateixa indústria alimentària de la fracció plasmàtica de la sang de porc generada per escorxadors que utilitzen sistemes oberts de recollida higiènica.1. En la primera part s'analitza la composició de la sang higiènica que s'està recollint actualment i s'estudien les característiques tant físico-químiques com microbiològiques que determinen la seva qualitat. La caracterització s'ha realitzat amb sang recollida en diferents escorxadors industrials de les comarques de Girona i s'ha centrat principalment en l'estudi de la contaminació microbiològica i el nivell d'hemòlisi de la sang. S'ha fet un disseny experimental que ha permès alhora valorar l'efecte d'alguns factors sobre la qualitat de la sang: possibles diferències relacionades amb (1) la climatologia del període de l'any en el qual es fa la recollida, (2) particularitats dels escorxadors (grandària, sistemes de dessagnat, tipus, dosi i sistema de dosificació de l'anticoagulant, condicions de processament, maneig i emmagatzematge després de la recollida, etc.).Els resultats obtinguts ens permeten constatar que, en les condicions actuals, la sang que s'està recollint en els escorxadors estudiats no es pot considerar adequada per a una matèria primera de productes destinats a alimentació humana. La major part de la microbiota contaminant s'adquireix en el propi sagnador. S'ha constatat que el sistema de dessagnat en posició horitzontal podria ser una mesura útil per minimitzar la contaminació d'origen fecal o provinent de la pell de l'animal sacrificat i que la separació immediata de les fraccions en el propi escorxador també pot contribuir a reduir la contaminació. Així doncs, en el benentès que l'efectivitat pot obtenir-se del conjunt de mesures preses, més que de l'aplicació d'una sola d'elles, es suggereix la introducció d'una sèrie d'actuacions que potser permetrien reduir els nivells de contaminació que s'obtenen actualment.El tractament mecànic de la sang, el sistema d'addició d'anticoagulant, el volum i concentració de la solució anticoagulant afegida i el període d'emmagatzematge són els factors responsables de l'hemòlisi; mentre que nivells elevats de contaminació microbiològica i el tipus d'anticoagulant utilitzat deterrminen la velocitat d'increment de l'hemòlisi de sang refrigerada. S'ha constatat que quan la sang no pot ser processada immediatament i s'ha d'emmagatzemar en refrigeració és millor utilitzar citrat sòdic enlloc de polifosfat com a anticoagulant ja que l'increment d'hemòlisi es dóna més lentament.2. El segon apartat s'ha centrat en la fracció plasmàtica de la sang. S'ha utilitzat la deshidratació per atomització com a tecnologia de conservació del plasma i s'ha fet una caracterització del producte en pols resultant des del punt de vista de composició i qualitat. A més de la contaminació microbiològica, que determina la qualitat higiènico-sanitària del producte, s'ha realitzat un estudi de les propietats funcionals que podrien fer del plasma un producte útil en la formulació d'aliments (capacitat escumant, emulsionant, gelificant). S'ha fet especial incidència en (1) determinar l'efecte del procés tecnològic de deshidratació sobre la funcionalitat del producte i (2) estudiar l'estabilitat del plasma deshidratat durant el període d'emmagatzematge.En les condicions de deshidratació per atomització aplicades no es provoca desnaturalització de la fracció proteica i s'obté un producte suficientment deshidratat, amb una aw<0,4 per permetre suposar una bona estabilitat. Algunes mostres de plasma deshidratat analitzades presenten nivells detectables de determinats residus (sulfonamides i corticosteroides). La qualitat microbiològica del producte en pols reflecteix l'elevada contaminació que contenia la matèria primera utilitzada, tot i que la deshidratació per atomització ha comportat la reducció en una unitat logarítmica de la càrrega contaminant. Els recomptes generals de microorganismes són encara preocupants i més tenint en compte que s'ha evidenciat la presència de toxines estafilocòciques en algunes mostres.L'avaluació de les propietats funcionals del producte deshidratat en relació a les que presentava el plasma líquid ens ha permès comprovar que: (1) El procés de deshidratació no ha afectat la solubilitat de les proteïnes. Això, junt amb el fet que no s'obtinguin diferències significatives en l'anàlisi calorimètrica de mostres líquides o deshidratades, permet concloure que el procés no provoca desnaturalització proteica. (2) No s'observen efectes negatius del procés tecnològic sobre la capacitat escumant ni en l'activitat emulsionant de les proteïnes plasmàtiques, dues propietats funcionals que possibiliten l'aplicació del plasma amb aquestes finalitats en l'elaboració d'alguns aliments. (3) La deshidratació tampoc perjudica de manera important les característiques dels gels que s'obtenen per escalfament, ja que els gels obtinguts a partir del plasma líquid i del plasma deshidratat presenten la mateixa capacitat de retenció d'aigua i no s'observen diferències en la microestructura de la xarxa proteica d'ambdós tipus de gel. Tanmateix, els que s'obtenen a partir del producte en pols mostren una menor resistència a la penetració.L'estudi d'estabilitat ens ha permès comprovar que la mostra de plasma deshidratat per atomització perd algunes de les seves propietats funcionals (facilitat de rehidratació, capacitat de retenció d'aigua i fermesa dels gels) si s'emmagatzema a temperatura ambient, mentre que aquestes característiques es mantenen un mínim de sis mesos quan el producte en pols es conserva a temperatura de refrigeració.3. En l'última part, tenint en compte les conclusions derivades dels resultats dels apartats anteriors, s'han assajat tres possibles sistemes de reducció de la contaminació aplicables a la fracció plasmàtica com a pas previ a la deshidratació, per tal de millorar les característiques de qualitat microbiològica i les perspectives d'estabilitat del producte durant l'emmagatzematge. S'ha determinat l'eficàcia, i l'efecte sobre les propietats del plasma deshidratat, que poden tenir tractaments d'higienització basats en la centrifugació, la microfiltració tangencial i l'aplicació d'altes pressions.Els tractaments de bactofugació aplicats permeten reduir entre el 96 i el 98% la contaminació microbiana del plasma. Aquesta reducció s'aconsegueix tant amb un sistema discontinu com amb un sistema continu treballant a una velocitat de 12 L/h, fet que permetria adaptar el tractament de bactofugació a un procés de producció industrial.Un sistema combinat de bactofugació en continu i microfiltració tangencial permet incrementar l'eficàcia fins a un 99,9 % de reducció. Cal tenir present, però, que aquest tractament provoca també una disminució de l'extracte sec que afecta negativament les propietats funcionals del plasma líquid. Malgrat suposar una pèrdua pel que fa al rendiment, aquest efecte negatiu sobre la funcionalitat no suposaria cap inconvenient si s'utilitzés la deshidratació com a tecnologia de conservació del plasma, ja que es podria corregir l'extracte sec durant la reconstitució del producte. Caldria avaluar si la millora en la qualitat higiènico-sanitària del producte compensa o no les pèrdues que suposa aquest sistema d'higienització combinat.Amb relació als tractaments d'alta pressió, de totes les condicions de tractament assajades, les pressions de fins 450 MPa permeten obtenir plasma sense modificacions importants que impedeixin la seva deshidratació per atomització. Així doncs, les condicions de procés que s'han aplicat són pressuritzacions a 450 MPa de 15 minuts de durada. La temperatura de tractament que s'ha mostrat més eficaç en la reducció dels recomptes de microorganismes ha estat de 40ºC. Els tractaments a aquesta temperatura permeten assolir reduccions del 99,97% i disminuir en un 80% la capacitat de creixement dels microorganismes supervivents a la pressurització en relació a la que presentava la població contaminant del plasma abans del tractament. L'estudi de l'efecte d'aquest tractament (450 MPa, 15 min i 40ºC) sobre les propietats funcionals del plasma ha permès observar que la pressurització comporta una disminució en la solubilitat del producte però una millora en les propietats de superfície -estabilitat de l'escuma i activitat emulsionant- i un increment de la capacitat de retenció d'aigua i de la duresa dels gels obtinguts per escalfament. Calen més estudis per confirmar i caracteritzar aquesta millora en la funcionalitat, així com per establir si el tractament de pressurització afecta també l'estabilitat del producte durant l'emmagatzematge.De totes les tecnologies d'higienització assajades, l'alta pressió és la que permet obtenir millors resultats en el sentit de poder garantir un producte de bona qualitat microbiològica i segur, des del punt de vista sanitari i tecnològic, per a la seva utilització com a ingredient alimentari. / Blood from slaughtered animals produced in industrial abattoirs can be used as a good raw material in both feed and food industries as regard to its good nutritional value and excellent functional properties. This study was undertaken to determine the possibility of the food industry to make use of the plasma obtained from porcine blood collected by means of hygienic open blood-collection systems in industrial abattoirs. The study has been divided into three parts with particular objectives that are specified below.1. The first part consisted on making the characterisation, from both physico-chemical and microbiological points of view, of the blood collected in several abattoirs. Microbial contamination is an important handicap in using the blood as a source of human food, as is the case of most industrial by-products. In the same way, small amounts of residual haemoglobin present in plasma, as a consequence of red blood cell hemolysis, induces off-flavours and discoloration in foods containing plasma. In this study a comparative analysis of the microbial quality and the level of hemolysis of porcine blood hygienically collected in six abattoirs from Girona was carried on. The evolution of hemolysis in blood stored at chilling temperatures for several days and the main factors promoting its increase during storage were studied. Our results indicate that the microbiological quality of the blood which was collected in those abattoirs was not as good as it had to be in order to be used for human consumption. It has also been stablished that the dose and concentration of anticoagulant added to the blood were important factors affecting the hemolysis levels. The rates of hemolysis were strongly influenced by the type of anticoagulant used and the level of microbiological contamination of blood. To reduce the rate of hemolysis during storage the use of sodium citrate as anticoagulant rather than polyphosphate is recommended.2. The second part of the study was focused on the plasmatic fraction of the blood. Spray drying was applied as a technology to preserve the plasma. The composition and the quality of the powder have been determined by means of physico-chemical and microbiological analyses and the evaluation of some functional properties (solubility, foaming capacity, emulsifying activity and the characteristics of heat-induced gels). The effect of the drying process on these properties and the stability of the dried plasma during storage were also studied.Spray-dried plasma had a residual water content of about 11 %, which represented less than 0.4 in the aw value. It was still very contaminated and staphylococcal enterotoxines were found in several samples. The comparison between the functional properties of spray-dried and liquid plasma led to the following conclusions: (1) Spray-drying did not produce a significant denaturation but only little structural modifications of the plasma proteins which did not affect their solubility. (2) The dehydrated product had similar foaming properties and emulsifying activity to the liquid plasma. (3) The water holding capacity and the microstructure (SEM) were the same for gels obtained from both liquid and dehydrated plasma but the hardness of heat induced gels from spray-dried plasma was reduced as compared with those obtained from liquid plasma. These properties remained stable as long as three month at room temperature and at least for six month under chilling conditions.3. In the last part, some technological methods to reduce microbial contamination of plasma before it was dried were tested. The interest in maintaining functional properties of plasma proteins supposes a limitation on the use of conventional thermal systems to improve its sanitary quality. Because of this, bactofugation, microfiltration and high hydrostatic pressure (HHP) were assayed as possible alternative sanitising technologies.Between 96 to 98% of reduction in microbial counts were achieved by means of bactofugation. A combined system of bactofugation and tangential microfiltration improved the efficacy up to 99.9% of reduction but also provoked a decrease of 0.5% in the dry matter content of plasma. High pressure treatments at operating pressures of 450 MPa applied during total compression times of 15 min led to different results depending on the processing temperatures. Treatments done at 5ºC led to reductions of about the 90% in the microbial counts and to 20-50% decreases in the growth ability of the survivors. At 25 and 40ºC the efficacy was increased to reduction values of 99.82 and 99.97%, respectively. The decreases in the growth capacity were about 50% at 25ºC and up to 80% at 40ºC. The main conclusion of this study was that high hydrostatic pressure at 450 MPa, during 15 min at 40ºC is an effective method to improve the microbiological quality of plasma. The original contamination was reduced from initial counts of 105-106 cfu/mL to final counts of 10-103 cfu/mL and there were no appreciable negative effects on the functional properties of the product.
278

Potencialidades de logística reversa do resíduo de gesso da indústria da construção civil / Potentialities for reverse logistics of gypsum waste from the construction industry

Kochem, Keila 08 December 2016 (has links)
O presente estudo teve por objetivo geral delinear o atual panorama de gerenciamento de resíduo de construção e demolição (RCD) e a geração de resíduos de gesso (RGs) no estado do Paraná, identificando as principais potencialidades de aproveitamento do resíduo de gesso no que se refere à logística reversa. Paralelamente realizou-se o diagnóstico do gerenciamento de RCD e RG nos 20 maiores municípios geradores de resíduo do estado do PR, por meio da aplicação de questionários auto preenchidos. O RCD da cidade de Cascavel foi caracterizado segundo NBR 10.004 e o RG, por sua vez foi caracterizado quanto às propriedades físico-químicas (Composição Química, Massa específica, Massa unitária, Análise Granulométrica, Análise Termogravimétrica, e Absorção de Água). Por meio de levantamento bibliográfico fez-se a compilação dos principais estudos voltados ao aproveitamento/reciclagem do RG. Com base no levantamento sobre os potenciais receptores de resíduos de gesso no Estado Paraná, que poderiam absorver os RGs como matéria-prima, foram projetados fluxos para a logística reversa do gesso, sendo realizada a análise econômica para o aproveitamento do RG como matéria-prima na produção de cimento. Com base no estudo realizado, o panorama de gerenciamento de RCD no estado do Paraná leva a concluir que o gerenciamento de RCD ainda é um desafio. Na maioria dos municípios somente uma parte dos RCDs é coletada e encaminhada a unidades de disposição adequadas. A reciclagem de RCD é incipiente e as políticas voltadas ao gerenciamento de RCD estão em fase de amadurecimento. Em relação aos RGs, não há separação deste resíduo e a logística reversa seguida de reaproveitamento/reciclagem é praticamente inexistente. A amostragem dos RCDs gerados no município de Cascavel demonstrou uma composição de RCD parecido com a maioria dos municípios brasileiros (“Classe A” 86,29 %; “Classe B” 12,36%; “Classe C” 0,29 % e “Classe D” 1,05 %). Em relação à caracterização do RG comum e acartonado, os resultados indicam que RG possuem propriedades físico-químicas compatíveis com a matéria-prima natural (Gipsita), o qual pode ser reaproveitado como material de construção a partir de processos simples de tratamento. Entre as principais formas de reaproveitamento/reciclagem identificadas no presente estudo, a utilização como matéria-prima na indústria do cimento é a alternativa mais concreta no momento, já que as cimenteiras demonstram interesse na utilização desse material. Paralelamente esta alternativa possui mercado consumidor certo (cimenteiras) que demanda grandes volumes. No entanto, existe a necessidade de uma regularidade no envio das cargas de RG às cimenteiras, com garantia de fornecimento desse material, em volume e periodicidade de envio. Nesse sentido, maiores volumes sendo recebidos e processados poderiam diluir os custos e reduzir o preço da tonelada do gesso reciclado, o que demonstra que a necessidade de se trabalhar com regiões, bem como considerar a alternativa do reaproveitamento local. / The present study, had as general objective to design the current construction and demolition waste (CDW) and the generation of gypsum waste (WG) in the state of Paraná, identifying the main potential of the use of plaster residue in relation to reverse logistics. At the same time, the diagnosis of CDW and GW management was carried out in the 20 largest municipalities that generate waste in the State of Paraná, through the application of self-filled questionnaires.The CDW of Cascavel was characterized according to NBR 10.004 and the WG, was characterized as physicochemical properties (Chemical Composition, Specific Mass, Unit Mass, Particle Size Analysis, Thermogravimetric Analysis, and Water Absorption). Through a bibliographical survey was made the compilation of the main studies related to the use / recycling of the GW. Based on the survey on the potential receptors for WG in the State of Paraná, which could absorb GW as feedstock, was elaborated flows for the reverse logistics of gypsum, made the economic analysis for the use of WG as raw material in the production of cement. Based on the study, the CDW management landscape in the state of Paraná leads to the conclusion that the management of CDW is still a challenge in the state. In most municipalities only a portion of the CDW are collected and destined to adequate disposal units, and CDW recycling is incipient and the policies aimed at the management of CDW are in the process of maturing. There is no separation of GW and reverse logistics followed by reuse / recycling is practically non-existent. The CDW sampling generated in the municipality of Cascavel showed an CWD composition similar to most Brazilian municipalities (Class A 86.29%, Class B 12.36%, Class C 0.29% and Class D 1.05%).In relation to the characterization of the WG, the results indicate that have physicochemical properties compatible with the natural Gypsum, which can be reused as construction material from simple treatment processes. Among the main forms of reuse / recycling identified in the present study, the use as in the cement industry is the best alternative at the moment, since the cement plants show interest in the use of this material and are located in regions close to the generation sites studied here. At the same time, this alternative has a certain consumer market (cement industries) that demands large volumes. Economic viability studies have demonstrated that the WG processing received in Cascavel for use in cement manufacturing may be a viable alternative.However, there is a need for regularity in the send of WG loads to cement plants, with a guarantee of supply of this material, in volume and periodicity of shipment. In this sense, larger volumes being received and processed could dilute costs and reduce the price of the tonne of recycled gypsum, which demonstrates the need to work with regions as well as consider the alternative of local reuse.
279

Estudo da álcali-ativação de pó de blocos cerâmicos com cal hidratada / Alkali-activation study of ceramic bricks poder with hydrated lime

Macioski, Gustavo 26 April 2017 (has links)
Materiais cerâmicos provenientes de blocos e telhas presentes nos resíduos da construção civil são considerados contaminantes na produção de agregados reciclados, pois apresentam reduzida resistência mecânica à compressão e ao impacto, além de elevada porosidade. Estas características fazem com que argamassas e concretos produzidos com agregados reciclados mistos tenham baixa resistência à compressão e elevada absorção de água, devido a porosidade intrínseca desses agregados. Como uma alternativa para o aproveitamento tecnológico deste tipo de material, a cerâmica passou a ser estudada como matéria prima da álcali-ativação, seja por meio da combinação direta com a cal hidratada ou como adição ao cimento Portland (reação pozolânica). O objetivo deste trabalho é estudar a álcali-ativação de pó de blocos cerâmicos com cal hidratada, visando propriedades aglomerantes, para estudar o potencial pozolânico do agregado reciclado misto. Para isso, o estudo foi realizado em três etapas: avaliação da reatividade do pó de blocos cerâmicos em função da temperatura de sinterização; avaliação da reatividade do pó de blocos cerâmicos em função do tamanho das partículas e do tipo de ativador básico utilizado e, avaliação da cinética da reação de álcali-ativação em função da relação molar SiO2/CaO, além do método de cura. A partir dos resultados obtidos, observou-se que a reatividade do pó de blocos cerâmicos sofre influência da temperatura de sinterização da argila e do tamanho das partículas. O bloco cerâmico comercial não atingiu os requisitos físicos para ser classificado como pozolana, obtendo no ensaio Chapelle o valor de 305 mg de Ca(OH)2 fixadas por grama de pozolana e 5,5 MPa de resistência mecânica com a cal no ensaio IAP. A adição de Ca(OH)2 no pó de blocos cerâmicos, com relação molar SiO2/CaO igual a 2,75, proporcionou a maior resistência mecânica à compressão, quando curada a 77 ºC e 90% de umidade relativa, atingindo 8,5 MPa aos 28 dias. No decorrer da reação de álcali-ativação do pó de blocos cerâmicos, observou-se baixo calor de hidratação e acelerado consumo de Portlandita. Ao final da reação, foi possível a determinação de fases de silicato de cálcio e silicato de alumínio hidratados por meio de difratometria de raios X e morfologias reticulares pelo ensaio de microscopia eletrônica de varredura. / Ceramic materials from bricks and tiles present in construction waste are considered contaminants in the production of recycled aggregates, as they have a low compressive and impact strength, as well as high porosity. These characteristics make mortars and concretes produced with mixed recycled aggregates have low compressive strength and high water absorption due to the porosity of the recycled aggregates. As an alternative to the technological use of this type of material, the ceramic has been studied as an alkali-activation raw material, either by direct combination with hydrated lime or as an addition to Portland cement (pozzolan reaction). The aim of this work is to study the alkali-activation of ceramic bricks powder with hydrated lime, aiming binding properties. For this, the study was carried out in three stages: evaluation of the reactivity of the ceramic bricks powder as a function of the burning temperature; evaluation of the reactivity of the ceramic bricks powder as a function of the particle distribution; and the evaluation of the alkaliactivation reaction kinetics as a function of the SiO2/CaO molar ratio, as well as the cure method. From the results obtained, it was observed that the reactivity of the ceramic bricks powder is influenced by the burning temperature of the clay and the size of the particles. The commercial ceramic bricks did not meet the physical requirements to be classified as pozzolan, obtaining in the Chapelle test the value of 305 mg of Ca(OH)2 fixed by gram of pozzolan and 5.5 MPa of compressive strength with lime in the IAP test. The addition of Ca(OH)2 in the ceramic bricks powder whose SiO2/CaO molar ratio was 2.75 gave the highest compressive strength when cured at 77 °C and 90% of relative humidity, reaching 8.5 MPa at 28 days. In the course of the alkali-activation reaction of the ceramic bricks powder, it was observed low hydration heat and accelerated portlandite consumption. At the end of the reaction it was possible to determine calcium silicate and aluminum silicate hydrated phases by X-ray diffraction and reticular morphologies by the scanning electron microscopy.
280

Avaliação do efeito de resíduos galvânicos sobre a vulcanização e as propriedades da borracha natural (NR) / Evaluation of the effect of galvanic wastes on the vulcanization and the properties of natural rubber (NR)

Alex Calcagno de Sales Santos 17 July 2009 (has links)
Com a Revolução Industrial e a adoção do modelo econômico urbano e industrial, baseado no consumo, ocorreu o aumento da geração de resíduos, frutos das diferentes atividades humanas. A galvanoplastia é um processo que embeleza e protege mecanicamente peças metálicas e está presente nas indústrias do setor metal-mecânico de Nova Friburgo. Neste processo, dois resíduos importantes são gerados: um oriundo do pré-tratamento das peças metálicas e outro das estações de tratamento de efluentes industriais. Neste trabalho, tais resíduos, denominados de (RGs), foram incorporados à borracha natural (NR) em substituição total ou parcial ao óxido de zinco (ZnO). O possível efeito ativador dos RGs sobre a vulcanização e as propriedades da borracha natural foi investigado. As misturas foram realizadas em um misturador de calandras, utilizando-se um sistema convencional (CV). A cinética de vulcanização foi estudada nas temperaturas de 150C, 160C e 170C, através de ensaios reométricos e a determinação de parâmetros tais como: tempo de pré-cura (ts1); tempo ótimo de vulcanização (t90); torques mínimo (Ml) e máximo (Mh); constantes de velocidade; e, energias de ativação. Com relação às propriedades mecânicas, a resistência à tração e a resistência ao rasgamento foram determinadas. As composições de NR contendo RGs apresentaram diminuição do tempo ts1, aumento das constantes de velocidade e diminuição das energias de ativação. No entanto, a resistência ao rasgamento foi mantida em um nível satisfatório apenas nas composições em que o ZnO foi substituído parcialmente em 25%. / With the Industrial Revolution and the adoption of urban and industrial economic model, based on consumption, there was an increased in the generation of wastes, as a result of different human activities. Electroplating is a process that embellishes and mechanically protects metallic parts and it is present in the industries of metalmechanical segment of Nova Friburgo. In this process, two important wastes are generated: one from pre-treatment of metal parts, other from industrial sewage station. In this investigation, these wastes, named RGs, were incorporated in the natural rubber (NR) in partial or total replacement to zinc oxide (ZnO). A possible activator effect of RGs upon vulcanization and properties of natural rubber was investigated. Mixes are prepared in a two-roll mixer using a conventional system (CV). Vulcanization kinetics was studied at 150, 160 and 170C through of rheometric tests and the determination of parameters such as: scorch time (ts1); optimum cure time (t90); minimum torque (Ml); maximum torque (Mh); constants rates (k); and, activation energies. In relation to mechanical properties, tensile and tear strength were determined. NR compositions with RGs presented a diminution in ts1 values, increase in the constants rates and diminution of activation energies. However, tear strength is maintained in a satisfactory level only in the compositions where ZnO was partially replaced in 25%.

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