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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.
61

Occupational narratives of pulp and paper mill workers in Corner Brook, Newfoundland : a study in occupational folklife /

Small, Contessa, January 1999 (has links)
Thesis (M.A.)--Memorial University of Newfoundland, 1999. / Bibliography: leaves 140-147.
62

Does market concentration motivate pulp and paper mills to vertically integrate?

Wang, Gewei. January 2005 (has links)
Thesis (M. S.)--Economics, Georgia Institute of Technology, 2006. / Haizheng Li, Committee Chair ; Patrick McCarthy, Committee Member ; Vivek Ghosal, Committee Member. Includes bibliographical references.
63

Integration of hydrothermal processes on a forest-based biorefinery site

Häreskog, Linnea January 2018 (has links)
The pulp and paper industry (PPI) is a business that produce large amounts of residues annually. Besides bark, large quantities of sludge are produced from the various parts of the industrial process. The sludge that comes from the biological wastewater purification process is denoted biosludge and is known as a particularly problematic waste product. It is of interest to reduce the amount of sludge from the PPI or to find new ways of handling the produced sludge. The common way to treat the PPI sludge is by incineration in the site’s bark boiler. The material is however difficult to dewater and often does more harm than good in the boilers. Different technologies to try and dewater the sludge further have been investigated previously, one that has recently been noted is hydrothermal treatment. The technology described in this thesis work is called hydrothermal carbonization (HTC) which uses water as a reaction media to turn the sludge into a coal-like material called hydrochar. The hydrochar has a higher heating value than the initial sludge and is more hydrophobic which makes it easier to dewater. This Master’s thesis describes the process technologies of the HTC process and presents some of the recent work done within the area. The properties of different residues from the PPI are presented before the integration of an HTC process on the biorefinery site in Domsjö, Sweden is discussed using previously published articles. A survey concerning sludge from industries within a 500 km range of the Domsjö biorefinery site is made to investigate whether residual streams similar to the ones at the Domsjö site are available in the vicinity. The results show that an HTC process demands energy in the form of steam and/or electricity. A previously made pinch and total site analysis show that the most accessible steam at the Domsjö biorefinery site, that most appliances and process steps uses, is at 7 bars. There are also steam levels of 20 and 32 bar in the area, which is within the range an HTC plant requires. The HTC process water demands further treatment which puts an extra stress on the already existing water purification process. The Domsjö biorefinery site produces 6000 tonnes of biosludge per year. Several HTC companies produce units that normally treat 20000-50000 tonnes of sludge per year, which indicates that additional sludge could be added to reach full capacity. The survey shows that there are similar materials available in the surroundings. It is concluded that further investigations concerning the sludge materials must be made before real implementation consequences can be calculated.
64

Modification of a Moving Bed Biofilm Reactor(MBBR) due to radically changed process conditions : A case study of Kvarnsveden paper mill

Johansson Macedo, Liv May January 2018 (has links)
Papermaking process require large amounts of energy and water; therefore, pulp and paper mills can be potentially very polluting. The wastewater resulting from the papermaking process must be carefully managed as it is very rich in dissolved organic matter and contain compounds that make it difficult to treat. MBBR technology emerged as a possibility to increase the treatment capacity and to make more compact treatment systems designed to remove high organic loads, since in addition to having biomass in suspension as the activated sludge process, also has biomass adhered to plastic supports. This research was commissioned by Stora Enso Kvarnsveden and emerged in need of a bioreactor modification due to reduction of the wastewater load after the closure of PM11 in 2013 and PM8 in 2017. An evaluation of the performance of bioreactors is necessary with possible results to only run one bioreactor in the future and save energy. For performance analysis, two weeks of measurements were performed, one with the two bioreactors running at the same time and one with only K150 reactor running, trying to simulate what happens if one of them is stopped. Analysis of the main operating parameters of the MBBR system were evaluated during this research. As result, it was recommended an action to remove the excess of adhered biomass and an increase of the filling rating to 50%, in order to optimize TOC reduction.
65

Contextualizing Industry 4.0 in the Pulp and Paper industry : A case study at Stora Enso / Kontextualisering av Industri 4.0 i pappers- och massaindustrin : En fallstudie hos Stora Enso

Persson, Björn January 2018 (has links)
Leading industrial nations invest to try to increase advanced manufacturing and innovation to catch up in a free-market world. One common vision for these investments has been Industry 4.0. In short can this topic be described as the internet moving into the industry. The concept is relatively new and has become one of the most discussed topics during the last couple of years in many manufacturing conferences. However, the industry is so far lacking a clear definition of the concept, and much of the focus is on laboratory experiments rather than industrial applications. The research that has been conducted so far has not involved the process industry, where this thesis will operate. The purpose of this study is to contribute to the understanding of how Industry 4.0 can be related to the pulp and paper industry by contextualizing the concept, and function as a “door-opener” for further research. Potentials, sustainability aspects and a concrete example has been used to comprehend this. The study has been designed with a qualitative approach through semi-structured interviews at the specific case company Stora Enso, Skoghall. As the concept of Industry 4.0 not yet has an explicit definition the start of the thesis was therefore to create a theoretical framework of the theory to relate to during the rest of the study. The findings of the research show that Industry 4.0 in the pulp and paper industry focuses on Availability through possibilities of prediction and response improvement. The concept should emphasis on keeping the production ongoing with fever break-downs and increased Quality of the products. Communication improvements will be essential in reaching the new industry level, with connecting the whole plant as a crucial part. The thesis contributes with a first insight to what Industry 4.0 will mean to the pulp and paper industry and how it contextualizes in the sector. / Framträdande industriella nationer investerar idag för att öka den avancerade tillverkningen och antalet innovationer för att hänga med i den fria marknaden. En gemensam vision för de här investeringarna är Industri 4.0. I korta drag kan det beskrivas som att internet flyttar in i industrin. Konceptet är relativt nytt och har kommit att bli ett av de mest diskuterade områdena under de senaste åren på tillverkningskonferenser. Industrin saknar dock en tydlig definition av konceptet, och mycket av fokus gällande ämnet hamnar på laborationsexperiment istället för praktiska applikationer. Vidare finns det ett behov av att titta på hur detta ser ut i processindustrin eftersom detta ännu inte granskats, vilket kommer vara området för uppsatsen. Syftet med denna studie är att bidra till förståelsen för hur Industri 4.0 kan relateras till pappersindustrin genom att kontextualisera konceptet och verkasom en ”dörr-öppnare” för vidare forskning. Möjligheter, hållbarhetsaspekter och ett konkret exempel har använts för att skapa förståelse för detta. Studien har designats med ett kvalitativt angreppssätt med semi-strukturerade intervjuer på det specifika fallet, Stora Enso Skoghall. Eftersom konceptet Industri 4.0 ännu saknar en tydlig definition började studien med att skapa ett teoretiskt ramverk för att kunna relatera till detta genom arbetet. Resultaten visar att Industri 4.0 i pappersindustrin fokuserar på Tillgänglighet genom ökade prediktions- och åtgärdsmöjligheter. Konceptet borde lägga vikt vid att hålla igång produktionen med färre avbrott och ökad Kvalitet på produkterna. Kommunikationsförbättringar kommer bli essentiella för att nå den nya nivån av industri, där integrationen av hela fabriken kommer spela en stor roll. Examensarbetet bidrar med en första inblick i vad Industri 4.0 kommer betyda för pappersindustrin och hur det kontextualiseras i branschen.
66

Avaliação da degradação ambiental por meio de testes de toxicidade com sedimento e de análises histopatológicas em peixes / Evaluation of environmental degradation by means of sediment toxicity tests and histopathological tests on fish

Paulo Cesar Meletti 14 August 2003 (has links)
As cidades e as atividades industriais e agrícolas geram uma infinidade de substâncias, muitas vezes desconhecidas, que quando lançadas nos corpos de água receptores podem por em risco a biota local e até mesmo a saúde humana. O presente trabalho avaliou o estado de degradação ambiental nas bacias dos rios Piracicaba, Mogi Guaçu (ambas no estado de São Paulo) e Tibagi (estado do Paraná), tendo como ferramentas os testes de toxicidade de sedimentos com peixes, em laboratório e in situ, análises histopatológicas dos animais expostos e análises físicas e químicas da água e do sedimento. Foram realizadas, ainda, análises das alterações histológicas em peixes expostos ao efluente final de indústria de papel e celulose, atividade presente nas três bacias estudadas. Os organismos-teste selecionados foram a espécie nativa de peixe Serrapinnus notomelas (Characiformes, Characidae) e a espécie padronizada, exótica, Danio rerio (Cypriniformes, Cyprinidae). As preparações histológicas foram realizadas com os peixes inteiros, possibilitando a análise dos órgãos-alvo brânquias, rim e fígado, em um mesmo corte. Nenhum organismo morreu após 96 horas de exposição às amostras de sedimento. No entanto, as análises histológicas revelaram alterações importantes, as quais foram sistematizadas para o cálculo do Índice de Alterações Histológicas (IAH) e do Valor Médio de Alterações (VMA), por órgão e por espécie, para cada localidade estudada. Os sedimentos provenientes das localidades de Sumaré (rio Atibaia) e de Piracicaba (rio Piracicaba) foram os mais tóxicos a ambas as espécies, de acordo com os índices calculados, seguidos pelos sedimentos de Campinas (rio Atibaia), Limeira (rio Jaguari) e Americana (rio Piracicaba). Os sedimentos da bacia do rio Mogi Guaçu foram menos tóxicos, mas aqueles provenientes das localidades Mogi Guaçu e Luiz Antônio (ambos a jusante de indústrias de papel e celulose) provocaram alterações renais e hepáticas significativas em D. rerio. Apesar de terem sido observadas alterações importantes nos peixes de ambas as espécies, expostas aos sedimentos da bacia do rio Tibagi, estas não foram tão intensas e freqüentes como aquelas observadas nos peixes expostos aos sedimentos das localidades das outras bacias hidrográficas. As análises físicas e químicas comprovaram a crítica situação de degradação do ambiente aquático na bacia do rio Piracicaba e alertam para os cuidados que deverão ser tomados com relação a esta e às bacias dos rios Mogi-Guaçu e Tibagi, cujos recursos estão sendo cada dia mais explorados. As graves alterações observadas nas brânquias, rim e fígado dos peixes expostos ao efluente de indústria de papel e celulose indicaram que o monitoramento da toxicidade desse tipo de efluente deve ser realizado por ferramentas mais sensíveis, tais como as análises histopatológicas em peixes. / Urban and industrial activities generate a large number of substances, frequently unknown, that if discharged into water body receptors can put at risk the whole aquatic biota, as well as human health. The present work evaluated the state of environmental degradation in the basins of rivers Piracicaba, Mogi Guaçu (both in São Paulo state) and Tibagi (Paraná state), using as tools the toxicity tests with sediments and fishes as test-organisms, for both laboratory and in situ evaluations, together with histopathological analyses of exposed animals and chemical and physical analysis of sediments and water. Also, histological alterations in fishes exposed to the final pulp-mill effluent were analyzed. The species selected as test-organisms were the native species of fish Serrapinnus notomelas (Characiformes, Characidae) and the standard exotic species Danio rerio (Cypriniformes, Cyprinidae). Hystological preparations were performed with whole fish specimens, what allowed the analysis of the target-organs: gills, kidney and liver in the same section. No fish mortality was found after 96 hours exposition to the sediment samples. Nevertheless histological analyses revealed important alterations, which were used to calculate the histological alteration index (IAH) and the mean value of alterations (VMA), for each organ and species, in each locality evaluated. Sediments coming from Sumaré (Atibaia river) and Piracicaba (Piracicaba river) were the most toxic to both species, according to the calculated index, followed by the sediments from Campinas (Atibaia river), Limeira (Jaguari river) and Americana (Piracicaba river). The sediments of Mogi Guaçu riber basin had a lower toxicity, but those coming from Mogi Guaçu and Luiz Antônio (both localities placed downstream pulp-mill plants) have caused significant alterations in kidney and liver of D. rerio. Although important alterations were found for both species of fish exposed to the sediments from Tibagi river basin, these were not as intense and frequent as those observed in the fishes exposed to the sediment from the other localities studied. Physical and chemical analysis corroborated the critical degree of environmental degradation of Piracicaba river basin and must be considered as an early warning for the measures that must be taken in relation to this and also to Mogi-Guaçu and Tibagi basins, where resources are increasingly being overexploited. The severe damage found in gills, kidney and liver of fishes exposed to the pulp-mill effluent suggest that monitoring this type of effluent must include a high sensibility tool, as the histopatological analysis on fish.
67

Obtenção de um efluente sintético do processo de branqueamento da indústria de papel e celulose / Obtainment of a synthetic effluent of the bleaching process in a pulp and paper mill

Thiago José Momenti 10 May 2002 (has links)
A necessidade de produção de papel por processo ambientalmente corretos é um grande desafio. A polpa celulósica branqueada gera um dos efluentes mais problemáticos e estudados atualmente. O tipo de efluente na planta de branqueamento é mais importante que a quantidade gerada. O efeito da DBO no corpo receptor desse resíduo não é o principal problema, o problema está na geração dos compostos organoclorados, que estão dissolvidos nesse efluente. Muitas substâncias desse grupo são tóxicas e também podem ter efeitos carcinogênicos e mutagênicos. O estudo desse tipo de efluente em sistemas de tratamento biológico é de extrema importância e é tema de diversos trabalhos científicos. Entretanto, há algumas dificuldades relacionadas com a viabilidade de composição, a obtenção, o manuseio e o armazenamento de amostras desse tipo de efluente em laboratórios de pesquisa. O objetivo desse trabalho foi, portanto, obter um efluente sintético em escala laboratorial, sob condições controladas, que pudesse simular o comportamento de um efluente gerado em uma planta de branqueamento, quando em um sistema de tratamento biológico. Para isso, partiu-se de uma amostra de polpa celulósica não-branqueada e realizou-se a etapa de branqueamento no laboratório sob condições semelhantes às industriais, obtendo-se assim, o efluente desejado, que foi chamado de Efluente Sintético. A comparação foi realizada através da caracterização físico-química deste efluente e de um efluente de uma planta industrial de branqueamento, chamado de Efluente Industrial. Reatores anaeróbios operando em batelada foram utilizados para avaliação do comportamento destes influentes de tratamento biológico. Observou-se que o comportamentos de ambos os efluentes pôde ser considerado semelhante. A avaliação foi feita através do acompanhamento da produção de gás metano e eficiências de remoção de DQO e AOX. / The necessity of producing paper by environmental friendly processes is a big challenge; bleached cellulose pulp produces one of the most problematic and studied kind of effluent nowadays. The kind of effluent produced in the bleaching mill is more important than the quantity of this effluent. The effect of the BOD of this effluent in the receiving water is not the main problem, the problem is on the generation of organochlorines compounds that are dissolved in this effluent. A lot of substances of this group are toxic and can show carcinogenic and mutagenic effects. The study of effluent in biologic systems of treatment is extremely important and is theme of a variety of scientific works. However, there are some difficulties related to the variability of composition, the obtainment, the handling and the storage of samples of this kind of effluent in a research laboratory. Therefore, the purpose of this work was to obtain a synthetic effluent in a laboratory scale, under controlled conditions, that could simulate the behavior of an effluent produced in a bleaching mill, when in a biological system of treatment. For this, it was used a sample of a unbleached cellulose pulp and it was done the stage of bleaching in the laboratory under similar conditions to the mill\'s, obtaining in this way the desired effluent, that was called Synthetic Effluent. It was done a comparison between this effluent and a bleaching mill effluent, that was called Industrial Effluent, by a physical and chemical characterization. It was used anaerobic batch reactors to make a evaluation of the behavior of these effluents in a biological system of treatment. It was observed that the behavior of both effluents can be considered similar. The evaluation was done by the observation of methane gas production and by the efficiencies of COD and AOX removal.
68

Devenir de l’arsenic dans une papeterie : étude de cas / Arsenic fate in a pulp and paper mill : a case study

Michon, Clémence 04 February 2011 (has links)
Les objectifs de ce travail étaient de déterminer les sources et le devenir de l’arsenic dans une papeterie vosgienne, et en particulier dans sa station d’épuration, afin de comprendre les variations de la concentration en arsenic dans l’effluent traité par la station et rejeté dans la Moselle.Les papiers récupérés utilisés pour la production de pâte désencrée représentent la source majoritaire d’arsenic pour la papeterie, puis les combustibles incinérés dans le secteur énergie. Les sorties majoritaires sont les cendres produites par le secteur énergie, puis le papier produit. Le devenir de l’arsenic dans le procédé de désencrage est complexe et implique des phénomènes de transfert entre le circuit de la pâte à papier et le circuit des eaux. L’arsenic présent dans les eaux blanches semble provenir des matières en suspension. Des dysfonctionnements dans le secteur énergie ont causé le départ de cendres produites dans la chaudière à la station d’épuration via les eaux de lavage du laveur de fumées. Ces cendres peuvent avoir une concentration en arsenic très importante et pourraient être l’une des causes des dépassements de la limite de rejet en arsenic. La station d’épuration peut éliminer de la phase aqueuse jusqu’à 50 % de l’arsenic entrant à la station après neutralisation/décantation et traitement par boues activées. Un traitement tertiaire par coagulation (par des sels d’aluminium) / floculation / flottation permet de diminuer encore la concentration en arsenic dans le rejet en fonction des conditions de fonctionnement / This study was about the sources and the fate of arsenic in a pulp and paper mill located in the Vosges, and particularly in the wastewater treatment plant, in order to understand the variations of the arsenic concentration in the treated effluent discharged in the Moselle River.The recovered papers used for the production of deinked pulp are the main source of arsenic for the pulp and paper mill, followed by the solid fuels incinerated in the boiler of the energy area of the mill. The main outputs are the ashes produced by the boiler, then the produced paper. The fate of the arsenic in the deinking process is complex and involves transfer phenomena between the pulp and the white water of the process. Arsenic present in white water could come from the suspended solids. Malfunctions in the energy area have caused the departure of ashes to the wastewater treatment plant via the washing water of the flue gas washer. Those ashes may contain a high arsenic concentration and could be one of the sources of the large variations of the arsenic concentration in the effluent of the wastewater treatment plant. This wastewater treatment plant is able to eliminate up to 50% of arsenic of the effluent thanks to neutralization/decantation and biotreatment by activated sludge. A tertiary treatment by coagulation (with aluminum salts) / flocculation / flotation permits to decrease the arsenic concentration in the effluent according to the operating conditions
69

Advanced Oxidation Processes for removal of COD from pulp and paper mill effluents : A Technical, Economical and Environmental Evaluation / Avancerade oxidationsprocesser för reducering av COD i avlopp från massa & papperbruk : En teknisk, Ekonomisk och Miljömässig utvärdering

Karat, Irma January 2013 (has links)
In Sweden, the dominating source for emissions of degradable organic substances to water is the pulp and paper industry. The organic substances increase oxygen consumption in the recipient which subsequently threatens aquatic species. Improved process engineering, process closures and use of external treatments have in recent years drastically lowered the Biological Oxygen Demand (BOD). However, the Chemical Oxygen Demand (COD) has not been reduced to the same extent, as some organic substances are more persistent and must be treated with more advanced techniques. Chemical precipitation, which can bind large parts of the remaining COD into solid matter, making it possible to be removed from the effluent by various separation technologies, contributes to an efficient COD removal. However, the direct operating cost for the treatment is high as large amount of chemicals are used in the process, and large quantities of sludge generated. In the near future EU pulp and paper industry will have to meet new regulatory demands on COD discharges, and pulp mills in Asia, South-America and Oceania will meet stringent discharge demands. It is therefore of interest to review alternative treatments in regards to technical, environmental and economical feasibility in the treatment of pulp and paper mill wastewaters. Much interest has been shown for Advanced Oxidation Processes (AOP), which is why these techniques have been evaluated in this thesis. The first part of the report consists of a literature review where processes with the following oxidants have been reviewed: 1. Ozone (O3); 2. Ozone + Hydrogen peroxide (O3/H2O2); 3. Fenton’s reagent (Fe2+/ H2O2); 4. Ozone + Ultraviolet light (O3/UV); 5. Hydrogen peroxide + Ultraviolet light (H2O2/UV); 6. Photo-Fenton’s reagent (Fe2+/ H2O2/UV); 7. Titanium dioxide + Ultraviolet light (TiO2/UV). Ozone treatment (1) and ozone in combination with hydrogen peroxide (2) were chosen for further experimental studies. The experiments were conducted at Wedecos (Xylem Water Solutions) laboratory in Germany and tested on wastewater from three different Swedish mills: A, B and C. The experimental results indicate that treatment with ozone is an efficient method for elimination of COD from pulp and paper mill wastewaters. A relatively high COD reduction (41 % for Mill A, 31% for Mill B and 53% for Mill C) was achieved for all wastewaters with an applied ozone dosage of 0.2g O3/L, without an appreciable impact on other parameters such as pH, N-tot, NO2-, NO3-, NH4+, P-tot and PO43-. There are indications that the nature of the wastewater has an impact on the COD removal efficiency and that TMP wastewater is easier to oxidize in comparison to wastewater from sulphate mills. The combination with hydrogen peroxide did not show any further COD reduction compared to ozone treatment alone, thus confirming the results Ko et al. showed in their study in 2009. Oxidation with ozone is seen as more environmental alternative in comparison to chemical treatment (precipitation/flocculation) because contaminants in the wastewater are destructed rather than concentrated or transferred into a different phase, which leads to the decrease of COD, colour and toxicity without the need to handle large amounts of sludge. However, a subsequent biological treatment may be necessary for removal of BOD as a BOD increase is registered for all wastewater treated in this study. The costs are on the other hand higher in comparison to chemical treatment even though there are indications of cases when treatment with ozone can be profitable (e.g. if the cost for sludge handling increases in the future, price for chemicals increases and electricity price decreases). There are some uncertainties regarding the system and there is no clear evidence that toxic by-products are not formed. More research must be done and more full-scale installations must be reported before the pulp and paper industry is willing to invest in oxidation technology. / I Sverige, är massa- och pappersindustrin den dominerande utsläppskällan av nedbrytbart organiskt material till vatten. När det organiska materialet når recipienten ökar syreförbrukningen eftersom stora mängder syre erfordras för nedbrytningen av materialet. Detta leder i sin tur till att de vattenlevande organismerna hotas och utsätts för syrebrist. Förbättrad processteknik, ökad processlutning och utbyggnad av extern avloppsvattenrening har under de senaste åren drastiskt sänkt den biokemiska syreförbrukningen (BOD). Däremot har den kemiska syreförbrukningen (COD) inte reducerats i samma utsträckning då delar av det organiska materialet är mer persistent och måste behandlas med mer avancerad teknik. Kemisk fällning kan idag binda stora delar av det kvarvarande COD till fast material som sedan kan avlägsnas via olika separationsmetoder. En stor nackdel med den här typen av rening är att stora mängder kemikalier används som i sin tur genererar stora mängder slam som måste tas om hand, vilket introducerar höga driftkostnader. Inom en snar framtid kommer massa- och pappersbruk inom EU att möta nya regulatoriska krav för COD utsläpp, och bruk i Asien, Sydamerika och Oceanien kommer även de att möta väldigt hårda utsläppskrav. Det är därför av intresse att granska alternativa reningsmetoder och utvärdera dess tekniska, miljömässiga och ekonomiska genomförbarhet vid behandling av avloppsvatten från massa- och pappersbruk. Mycket intresse har visats för Avancerade Oxidationsprocesser (AOP), varför dessa tekniker valts att utvärderas i detta examensarbete. Första delen av rapporten innefattar en litteraturstudie där processer med följande oxidanter studerats: 1. Ozon (O3); 2. Ozon + Väteperoxid (O3/H2O2); 3. Fenton’s reagens (Fe2+/ H2O2); 4. Ozon + Ultraviolett ljus (O3/UV); 5. Väteperoxid + Ultraviolett ljus (H2O2/UV); 6. Foto-Fenton’s reagens (Fe2+/ H2O2/UV); 7. Titaniumdioxid + Ultraviolett ljus (TiO2/UV). Utav dessa valdes ozon behandling (1) och ozon i kombination med väteperoxid (2) för vidare experimentella studier. Behandlingarna har utförts vid Wedecos (Xylem Water Solutions) laboratorium i Tyskland och undersökts på avloppsvatten från tre olika svenska bruk; A , B och C. Experimentella resultat tyder på att ozonering är effektiv behandlingsmetod för reducering av COD i avloppsvatten från massa- och pappersbruk. En relativt hög COD reducering (41% för bruk A, 31% för bruk B, och 53% för bruk C)  uppvisades för samtliga avloppsvatten med en tillämpad ozondosering på 0.2 g O3/L, utan någon märkbar inverkan på andra parametrar så som pH, N-tot, NO2-, NO3-, NH4+, P-tot och PO43-. Det förekommer indikationer om att typ av avloppsvatten har en inverkan på COD reduktionen och att TMP avloppsvatten är lättare att oxidera i jämförelse mot avloppsvatten från sulfatmassabruk. Kombinationen av ozon och väteperoxid uppvisade ingen ytterligare COD reduktion i jämförelse mot ozon som enda oxidant, och bekräftade därmed de resultat Ko et al. uppvisade i sin studie 2009. Ozonering ses som ett miljövänligare alternativ till kemisk rening (fällning/flockning) eftersom föroreningarna i vattnet destrueras istället för att koncentreras, vilket innebär att COD, färg och toxicitet kan minskas utan att stora mängder slam genereras. Dock kan en efterföljande biologisk behandling vara nödvändig för avskiljning av BOD då en BOD ökning uppvisats för samtliga avloppsvatten i denna studie i takt med att COD brutits ned till lättnedbrytbart biologisk material. Kostnaderna är däremot höga i jämförelse mot kemisk fällning även om det förekommer indikationer på fall när behandlingen kan vara lönsam (t ex om slamhanteringskostnaderna blir högre i framtiden, inköpspriset för kemikalier ökar och elpriset sjunker). Det råder vissa tveksamheter gällande systemet och det finns inga konkreta bevis på att toxiska biprodukter inte bildas. Mer forskning måste utföras och fler fullskaliga installationer måste rapporteras och innan massa- och pappersindustrin är villig att investera i oxidationstekniken.
70

Exploring the potential of blockchain technology to improve transparency and traceability within the pulp and paper industry

Mohammad, Bakhtiar, Engström, Michelle January 2021 (has links)
The pulp and paper industry is currently facing major challenges. Owing to the substitution of fossil-dependent products with recyclable and biodegradable ones, there is an immense demand for fibre-based products. As a result, there is an urgent need to streamline the supply chain. Additionally, consumers are increasingly pressuring businesses within the industry to improve supply chain transparency as the importance of responsible sourcing of forest-based products are gaining increased attention. To mitigate these issues, a high level of transparency and traceability throughout the entire supply chain, incorruptible tracking systems and secure forest certification systems is of utmost importance within the industry. In recent years, a distributed ledger technology, referred to as blockchain has emerged as a promising technology for improving supply chain transparency and traceability owing to its unique characteristics of storing information in a decentralized and immutable manner. However, due to the novelty of this technology within a supply chain context, a comprehensive assessment is crucial in order to understand how the technology could be leveraged. In this regard, this thesis aims to explore the potential of blockchain technology to improve transparency and traceability within the pulp and paper industry. Owing to the inherent explorative nature of this research, a qualitative approach has been adopted. Through semi-structured interviews with different actors within the supply chain of pulp- and paper products, as well as blockchain experts within the field of supply chain management, cross-sections between the two fields are drawn. In addition, based on the expert interviews, a general blueprint for companies considering implementing blockchain technology is developed. The results of the study indicate several potential use-cases where blockchain technology could bring value to the pulp and paper industry. For instance, the results show that the technology could be harnessed to streamline the supply chain, improve the chain of custody of certified products, support sustainability reporting and improve the quality of products. Lastly, as pioneering research within the field, this thesis opens up a series of directions for future research. / Massa- och pappersindustrin står just nu inför stora utmaningar. På grund av utfasningen av fossilbaserade material har efterfrågan på fiberbaserade material ökat drastiskt. Till följd av detta ökar vikten av effektiva försörjningskedjor. Dessutom, i takt med att hållbart skogsbruk får en ökad betydelse i samhället, ökar pressen från konsumenter att öka transparensen gällande råmaterialets  ursprung.  För att tackla dessa utmaningar krävs en hög grad av transparens och spårbarhet genom hela värdekedjan.   Under de senaste åren har en typ av distribuerad databasteknik, även kallad blockkedjeteknik växt fram som ett lovande verktyg för att förbättra transparens och spårbarhet inom försörjningskedjor,  tack vare dess unika egenskaper att lagra information på ett decentraliserat och oföränderligt sätt. Detta är dock en relativt ny teknik och på grund av detta finns det behov av studier där teknikens användningsområden i branschen utforskas innan den implementeras.   I detta avseende syftar denna rapport till att utforska blockkedjeteknikens potential att förbättra transparens och spårbarhet inom massa- och pappersindustrin. På grund av den utforskande karaktären av denna studie har en kvalitativ metod använts. Genom semistrukturerade intervjuer med olika aktörer inom värdekedjan för massa- och pappersprodukter, samt experter inom blockkedjor, dras paralleller mellan de två områdena. Dessutom, baserat på intervjuerna med dessa experter, har en allmän steg för steg-guide tagits fram för att underlätta för företag att utvärdera potentialen av blockkedjor inom specifika användningsområden.  Resultaten av studien indikerar flera potentiella användningsområden där blockkedjeteknik kan medföra ett ökat värde. bland annat visar resultaten att tekniken kan utnyttjas för att effektivisera försörjningskedjan, förbättra spårbarheten standarden för certifierade produkter, underlätta hållbarhetsrapportering och förbättra kvaliteten på produkter. Slutligen, som en banbrytande forskning inom området, öppnar detta examensarbete upp för  framtida forskning.

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