| 1. |
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| 2. |
- Andreas, Lale, et al.
(författare)
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Chemical and hydraulic conditions in a landfill/deposit for wood-based ash
- 2004
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Ingår i: The 3rd Intercontinental Landfill Research Symposium November 29th - December 2nd, 2004 in Toya, Hokkaido Japan. - Hokkaido : Center for Applied Ethics and Philosophy, Hokkaido University. ; , s. 121-129
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Andreas, Lale, et al.
(författare)
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Effects of waste quality and landfill technology on the long-term behaviour of municipal landfills
- 1999
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Ingår i: Waste Management & Research. - 0734-242X .- 1096-3669. ; 17:6, s. 413-423
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Tidskriftsartikel (refereegranskat)abstract
- The pollution potential of old municipal landfills of the former German Democratic Republic (GDR) is not as bad as expected, even taking into consideration that most lack environmental protection systems. Compared with specific conditions in the former GDR (such as production and consumption), the disposal of waste and the long-term behaviour of landfills clearly differs from that in the old German federal states. Low quantities of deposited waste created slowly growing landfills, and therefore led to rapid degradation processes still in the aerobic milieu. As a result of the increasing similarity of waste quantities and composition in the new and old federal states after 1990, waste deposited today can be expected to have similar long- term behaviour and emissions as existing old Federal Republic of Germany (FRG) landfills which were operating during the 1970s and 1980s.
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| 4. |
- Andreas, Lale, et al.
(författare)
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Hydraulic performance of a land-fill top cover based on steel slag
- 2014
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Ingår i: Sardinia 2013. - Cagliari : CISA, Environmental Sanitary Engineering Centre.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The steel industry is expanding and following the amount of produced steel, more and more by-products and residuals are generated. About 17.6 million tonnes of steel slags arise in Europe every year. In Sweden about 18 % of the iron- and steelmaking slags are landfilled (Jernkontoret, 2012). One application for steel slags are landfill covers where large amounts of virgin materials are needed. The legal requirement in Sweden is directed towards the maxi¬mum amount of lea¬chate generated at the bottom of the landfill: < 5 and < 50 l (m2*a)-1 for landfill class 1 and 2, respec¬ti¬vely. To secure these demands, a layer of low permeability is needed to reduce water infiltration. The hydraulic load of this layer ought to be controlled by a protective water balance layer and an effective drainage layer.Previous investigations indicate that steel slags can be used as construction material for both liner and drainage layer (Herrmann et al., 2010). In order to verify this in full scale, five tests areas (A1-5) were constructed at a municipal landfill in Sweden between 2005 and 2011. The areas were designed using different mixtures of steel slags from the local steel company in the liner. The purpose of this study was to evaluate the hydraulic performance of the cover during the first years after installation.The design of the cover construction was varied like this: a mixture of 50 % electric arc furnace slag (EAFS) and 50 % ladle slag (LS) was tested as liner material in the first test area (A1). A2 and A3 were built using less LS and coarser fractions of EAFS since laboratory tests had given satisfactory results also for these recipes. High infiltration rates in A2 and 3 led to a return to the original weight proportions in A4 and 5, yet another EAF slag was introduced in these areas. The mixing and construction techniques were refined during the first years of the project time: while A1 was built with rather poorly conceived technique, as of A3 the method can be considered as technically mature and approved.The liner performance was evaluated by lysimetry: 10 lysimeters were installed below each test area. The infiltration below the liner corresponded to 44, 74, 71, 19 and 0.4 l/m2*year for A1 to A5. Compared to the legal limit of 50 l/m2*year, the covers of A2 and A3 allowed about 50 % more water to enter the landfill than stipulated.An initial increase of the infiltration was observed, which most likely is related to increasing water saturation of the liner material in the first period after construction. The saturation occurred fastest in A2, where basically no initial increase was observed, probably due to the long time that elapsed between construction and the first sampling event (260 days). In contrast, the saturation in A1 and A4 was quite slow which can be related to the smaller particle size of the slags in these areas and, hence, a less porous liner material. The decrease in A2 and A3 might be explained by mineral transformations within the slag matrix such as carbonation of calcium and magnesium leading to the precipitation of carbonates in the pores of the liner material. Future observations will show if the decreasing trend in A2 and A3 remains such that the infiltration eventually reaches a level falling below the legal limit.The results show that the infiltration criteria can be fulfilled under the condition that at least 50 % of the liner mix consists of ladle slag, a fine-grained slag with cementitious properties. With few adaptations the steel slag can be used with standard construction processes.
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| 5. |
- Andreas, Lale, et al.
(författare)
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Hydrotermisk karbonisering : en praktisk avfallsbehandlingsmöjlighet?
- 2017
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Rapport (populärvet., debatt m.m.)abstract
- Hydrotermisk karbonisering (HTC) är en behandling där ett fuktigt organiskt materialutsätts för en kombination av värme och tryck, t ex 200°C och 20 bar. Då löses näringsämnenupp, och strukturen hos det organiska materialet förändras, vilket leder tillatt det stabiliseras, finfördelas, och enklare kan separeras från oorganiska delar.HTC har tidigare mest används vid bränsleproduktion, men i den här studien stod metodenspotential för avgiftning och separation av avfall i fokus, och vilken roll HTCkan ha som avfallsbehandlingsmetod. Syftet med projektet var att bedöma potentialenav HTC som metod för att öka återvinningen av näringsämnen i en cirkulär ekonomimed samtidigt förbättrad avgiftning av avfall jämfört med biologisk behandling, ochminskade utsläpp av koldioxid genom annan användning av organiska avfall än sombränsle.För att uppnå målen genomfördes labbförsök med efterföljande kemiska analyser, ochresultaten låg till grund för en multivariat dataanalys och en livscykelanalys.Resultaten visar på en avgiftning genom en separation av halten av skadliga tungmetaller,och att värmevärdet ökar. Dock så bedöms det analyserade materialet inte kunnaanvändas till jordförbättringsmedel eller som anläggningsmaterial, vilket dock främstberor på att materialet redan var förorenat.HTC lämpar sig bäst för blöta avfall med en blandning av organiska och oorganiskadelar. En marknadsanalys visar på att 100 000-tals ton av dessa typer av avfall fallervarje år.Sammanfattningsvis så kan processen vara intressant som avfallshanteringsmetod,men mer forskning behövs gällande mekaniska egenskaper och mekanisk separation.
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| 6. |
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| 7. |
- Andreas, Lale
(författare)
-
Langzeitemissionsverhalten von Deponien für Siedlungsabfälle in den neuen Bundesländern
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Langzeitemissionsverhalten von Deponien für Siedlungsabfälle in den neuen BundesländernZusammenfassungZiel der vorliegenden Arbeit war die Beschreibung des Langzeitverhaltens von DDR-Deponien unter besonderer Berücksichtigung der Emissionen auf dem Sickerwasserpfad.Die Beschreibung umfaßte die untersuchten Deponiestandorte, die Deponierungspraxis in der DDR, charakteristische Eigenschaften der abgelagerten Abfälle sowie der nach mehrjähriger Lagerungszeit ausgekofferten Altabfallproben, die Sickerwasseremissionen der Deponie Döbeln-Hohenlauft, das Auslaugverhalten der Altabfälle in Mehrfachelutionsversuchen und die Sickerwasser- und Gasemissionen der Deponiesimulationsversuche.Als charakteristische Eigenschaften der DDR-Deponien, die für das Emissionsverhalten von Bedeutung sind, wurden folgende Punkte herausgearbeitet:langsames Deponiewachstum,fehlende oder sehr geringe Verdichtung,vergleichsweise intensive aerobe Prozesse zu Beginn der Ablagerung.Bedingt dadurch wurde ein Großteil der biologisch abbaubaren Bestandteile des Abfalls sehr schnell umgesetzt und trägt nicht zum langfristigen Emissionsverhalten bei.Die Abfallzusammensetzung von DDR-Altabfällen ist gekennzeichnet durch:hohe Anteile von Feinmaterial (bis zu 70 Masse% sind < 8mm),hohe Anteile mineralischer Stoffe, wie Aschen und Bauschutt,hohe Salzgehalte (Sulfat, Alkalien, Erdalkalien),eine hohe Säurepufferkapazität undgeringe Anteile organischer Abfälle.Dies führt zu einem wenig reaktiven Deponiekörper und den bei den meisten alten DDR-Deponien zu beobachtenden geringen Emissionen. Die wesentlichen Emissionen erfolgen auf dem Sickerwasserpfad, die Hauptkomponente dabei sind anorganische Salze. Hinsichtlich der Zusammensetzung können die DDR-Deponien am ehesten mit Asche-/Schlackedeponien verglichen werden, die in Zukunft den wohl wichtigsten Deponietyp in Deutschland darstellen werden.Auf der Basis der Untersuchungen zur Feststoffzusammensetzung der Abfälle und ihres Auslaug- und Emissionsverhaltens wurden desweiteren Prozesse diskutiert, die in DDR-Deponien in der Vergangenheit stattgefunden haben können bzw. die zukünftig möglich sind. Hierbei sind zu nennen:die Auslaugung von Salzen,Sulfatreduktion,Karbonatanreicherung im Feststoff.Mittels multivariater Datenanalyse konnte eine Einordnung der Deponieprozesse in eine späte anaerobe Phase mit Tendenz zu semi-aeroben Prozessen hin vorgenommen werden. Die methodischen Unterschiede zwischen Mehrfachelutions- und DSR-Versuchen wurden genutzt, um biologische Prozesse in den DSR zu identifizieren und bewerten. Im Ergebnis der Untersuchungen in Deponiesimulationsreaktoren wurden langfristige Emissionspotentiale EP und notwendige Nachsorgezeiträume bis zum Erreichen von Grenzkonzentrationen im Sickerwasser abgeschätzt. Sie sind in Tabelle 1 als Medianwerte zusammengefaßt dargestellt. Die Auswertung langjähriger Sickerwassermeßreihen der Deponie Döbeln-Hohenlauft bestätigte die Repräsentativität der DSR-Versuche und unterstützt die getroffenen Prognosen.Tabelle 1 Notwendige Zeiträume TE bis zum Erreichen von umweltverträglichen Konzentrationen cE im Sickerwasser von DDR-Altdeponien [a] Grenzkonzentration cEDSR-EP(W-F ® ∞) Stoffaustrag FE bis cE [g/kg] W-FE bis cE [l/kg TS] Zeitraum TE bis cE [a]CSB200 mg/l0,60,20,557TOC 100 mg/l0,150,040,334NKj 70 mg/l0,250,091,2144Cl‾100 mg/l0,70,61,4167SO42‾250 mg/l2,72,61,5180 Die längsten Zeiträume sind für den Austrag von Stickstoff und Salzen, insbesondere des Sulfats, notwendig. Die Dauer wird im wesentlichen durch folgende Faktoren beeinflußt:Abfallzusammensetzung (Anteil neuer Abfälle auf den alten DDR-Deponien)WasserhaushaltLuftzutritt, Oxidation.Ein Ausblick auf das veränderte Emissionsgeschehen der nach 1990 weiter betriebenen DDR-Deponien zeigt, daß sich durch die Veränderungen in Abfallzusammensetzung und Ablagerungspraxis das Deponieverhalten deutlich verschlechtert hat, und eine Annäherung des Emissionsniveaus an die Verhältnisse von Siedlungsabfalldeponien der 70er/80er Jahre in den alten Bundesländern zu verzeichnen ist.Die erwarteten Nachsorgezeiträume gehen z. T. deutlich über heute in der Praxis diskutierte Werte hinaus. Um den Zeitrahmen bis zum Erreichen umweltverträglicher Sickerwasserkonzentrationen so zu verkürzen, daß die bei der Deponierung anfallenden Probleme von der gleichen Generation gelöst werden, die sie verursacht hat, sind aktive Maßnahmen zur Emissionsminimierung unbedingt notwendig.
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| 8. |
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| 9. |
- Andreas, Lale, et al.
(författare)
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Steel slags in a landfill top cover : Experiences from a full-scale experiment
- 2014
-
Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 34:3, s. 692-701
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Tidskriftsartikel (refereegranskat)abstract
- A full scale field study has been carried out in order to test and evaluate the use of slags from high-alloy steel production as the construction materials for a final cover of an old municipal landfill. Five test areas were built using different slag mixtures within the barrier layer (liner). The cover consisted of a foundation layer, a liner with a thickness of 0.7 m, a drainage layer of 0.3 m, a protection layer of 1.5 m and a vegetation layer of 0.25 m. The infiltration varied depending on the cover design used, mainly the liner recipe but also over time and was related to seasons and precipitation intensity. The test areas with liners composed of 50% electric arc furnace (EAF) slag and 50% cementitious ladle slag (LS) on a weight basis and with a proper consistence of the protection layer were found to meet the Swedish infiltration criteria of ⩽50 l (m2 a)−1 for final covers for landfills for non-hazardous waste: the cumulative infiltration rates to date were 44, 19 and 0.4 l (m2 a)−1 for A1, A4 and A5, respectively. Compared to the precipitation, the portion of leachate was always lower after the summer despite high precipitation from June to August. The main reason for this is evapotranspiration but also the fact that the time delay in the leachate formation following a precipitation event has a stronger effect during the shorter summer sampling periods than the long winter periods. Conventional techniques and equipment can be used but close cooperation between all involved partners is crucial in order to achieve the required performance of the cover. This includes planning, method and equipment testing and quality assurance.
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| 10. |
- Andreas, Lale, et al.
(författare)
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Use of secondary materials in landfill constructions
- 2007
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Ingår i: SARDINIA 2007. - Cagliari : CISA, Environmental Sanitary Engineering Centre. - 9788862650038
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Konferensbidrag (refereegranskat)abstract
- Many landfills are subject to closure in the near future. Roughly 2,000 hectares of landfill area have to be covered only in Sweden, equivalent to about 100 million tonnes of construction material. In addition to material costs in the order of tens of billions Euro, this also puts a strain on the environment through the exploitation of non-renewable virgin construction materials. Many landfill operators are considering alternative cover designs and materials in order to reduce resource spending. However, there is a fair amount of uncertainty with regard to functional and environmental consequences of using alternative (secondary) materials, both from the side of the companies and the authorities. This paper gives an overview over potential waste based construction materials and the use of some of them in projects presently ongoing in Sweden.Research on the use of secondary materials in landfill covers is quite recent. Substitutes for natural or synthetic materials in a landfill cover can be various types of waste from process industry, construction and demolition, or comparable activities. Alternative materials that have been investigated are ashes, slags, sewage and fibre sludges, treated soils and compost. Table 1 gives an overview over potential waste based construction materials. The total of potential materials is well in excess of the material needs for landfill construction, but they may not be available at the right time, place or quality.Besides being economically viable, the substitute materials should have suitable technical and environmental properties in order to secure a proper function of the construction. Experiences from three field studies (landfills at Tveta/Södertälje, Hagfors and Alvkarleby) are discussed looking at relevant issues during 1) construction, 2) active after care phase, and 3) long term processes.Using SCM poses additional problems compared to using conventional materials. Often, the supply of material has to be planned in advance and the materials may have to be stored on site. Storing, however, can cause problems if the materials have properties that change over time e.g. due to climate. For other materials storing may be necessary in order to achieve desired properties. One example is the ageing of strongly alkaline materials that react with atmospheric carbon dioxide and thus obtain better leaching properties. Table 1 Overview over potential waste based construction materials and examplesSourceExamplesMining and mineral industryWaste rock, flotation sand, etc...Construction and demolition (C&D)Crushed concrete, gypsum, asphalt, reinforced polymers, woodProcess industryDifferent types of slag from steel making, green liquor and fibre sludge from paper production, ashes and foundry wastesWastewater treatmentDigested sewage sludge, sandIncinerationBottom ash, fly ashThe evidence is mounting that the desired technical function of a landfill cover can be attained using suitable combinations of secondary construction materials. So far, all three field tests indicate leachate amounts between less then one and 30 l (m2 yr)-1 below the liner. In comparison with the average annual precipitation of about 600 mm yr-1 at the Swedish East coast, only 0.2-5 % of the precipitation seeped through the liner so far; i.e. the leachate generation is reduced with about 90 % or more.The issue is more if the materials may cause adverse impacts of the landfill and its recipients. A low water infiltration through the liner means that the most of infiltrating water is removed as drainage water and thus the leaching of the layers above the liner are of the greatest concern.Infiltrating water will yield a liquid to solid ratio of about 1-2 l kg-1 in the layers above the liner after about 10 years. The most mobile elements, such as nitrogen, will be leached to a great extent already at such low L/S ratios, so a forecast with regard to the need of treatment of drainage water points at about two to three decades.In the long term perspective the mineral changes of the construction materials become important. E.g. one of the incentives for using fly ash in liners is their capacity for chemical-mineralogical changes leading to the formation of clay-like structures. This could mean that a liner built of ashes will attain a lower permeability over time. Other mineral changes that can occur in ashes include the trapping of metals in the structure, e g in clay and carbonate phases.Much is still to be learned about the long term processes and the factors that control them. Ongoing studies include the assessment of climatic variables, different material combinations as well as the impact of landfill gases.The following conclusions can be drawn:The use of secondary materials in construction is important due to substantial resource and environmental impacts. An increased use should be beneficial, provided that the problems of using such materials can be managed.In addition to legislative and bureaucratic barriers, there are also practical issues which need to be dealt with in order to pave the way for a wider use of alternative construction materials. In the construction phase more planning is needed due to temporal and geographical limitation of the material availability. Some materials are not ready for immediate use but need to be pre-treated. All of these factors may cause a need for more space and time. A system for quality assurance comparable to that of traditional construction materials is another issue that needs to be resolved. Most likely some kind of legislative pressure is needed for this.In the medium term leaching of pollutants from the construction materials may be the most important issue when using secondary construction materials, which underlines the double standards applied, since traditional construction materials will not be scrutinized in the same manner. Anyhow, the long term interactions between materials and their environment need to be considered and further studies are necessary for secondary construction materials as well as for conventional materials. Existing data indicate both possibilities and problems.In the long term issues of material interactions will remain and the mechanical impact of mineral changes in the secondary construction materials may be added to the list of issues to clarify. Some of the material changes may be beneficial for the function of the construction, e.g. clay formation in liner materials may make them more impervious, but there may also be negative changes caused by deteriorated material properties. The rate and extent of such processes and the factors that enhance or retard them need to be understood better.Secondary construction materials have always been used and some of the "traditional" materials used today were wastes before. There is no reason to believe that this development should not continue.
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| 11. |
- Andreas, Lale, et al.
(författare)
-
Utvärdering av fullskaleanvändning av askor och andra restprodukter vid sluttäckning av Tveta Återvinningsanläggning
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In 2000 Telge Återvinning - a waste management recycling company - started investigating ashes from incineration of industrial and biowaste waste. The company was given a permit from the Swedish Environmental Court to cover four hectares of the house hold waste landfill area. In 2006 the company received an unlimited permit to cover the remaining part of the landfill when the works end some thirty years later.Ashes were used the first time in 1966 for testing. Literature studies indicated the ashes can have a low hydraulic conductivity under certain conditions. In 1999 collaboration started with the Division of Waste Science and Technology at Luleå University of Technology.Residuals from household and industrial waste were subject to investigation. Initially, biowaste incineration products were subject to testing and were later extended to other waste products, e.g. sludge, contaminated soils, foundry, and compost material. Several different sub-fractions of ashes were included in the investigation e.g. bottom and fly ash, various slag products after up-grading including dewatering, separation and sifting. Subsequently, a complete covering system of a landfill consists of residuals.Six test areas were outlined in order to give a good representation for cover construction in flat and steep areas with different compositions of liner material.The results show that in all areas the hydraulic conductivity construction yields less then 50 liters per square meters and years and can be less the than 5 liters in a repository for hazardous waste if required. In accordance with literature data the field observations show the liner material constructed only by ash material under certain conditions can form a monolithic structure due to very slow processes thus indicating small pore volumes that unable water - air to interact with other media.The concept of using ash can be related to natural analogues of volcanic ashes and has been used in old defence walls and other buildings thousand years back. The last part of the report brings a number of topics for future research and a discussion about problems to with the authorities to use residuals for covering landfills.
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| 12. |
- Bagheri, Marzieh
(författare)
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Integrated sewage sludge treatment scenarios – techno-economic analysis on energy and phosphorus recovery
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sewage sludge is a by-product of wastewater treatment that simultaneously gathers contaminants, valuable organic matter, and nutrients. The treatment of the increasing amount of sewage sludge is important from both pollution prevention and resource recovery perspectives as i) large shares of mineral phosphorus, listed as a critical raw material, terminate in the sewage sludge, and ii) energy recovery from sewage sludge can cover the energy-intensive demand of the treatment process. Previous research has identified sewage sludge combustion as a suitable treatment approach as it both addresses contaminant destruction and paves the way for efficient phosphorus recovery from the sewage sludge ash. The commercial development of this practice has, however, been slow. Therefore, this thesis aims to investigate the challenges in sustainable sewage sludge management, and to, in more detail, identify the economic viability of energy and phosphorus recovery from sewage sludge through combustion.The thesis’ aim is divided into two objectives addressed in three papers. First, to investigate how different aspects of sewage sludge management, such as contaminants, economic efficiency, technical aspects, and legislation, evolve and interact. This has been done by a review of sewage sludge management research over fifty years (Paper I). Second, to investigate the economic viability of simultaneous energy and phosphorus recovery from sewage sludge by comparing different technology and market scenarios. This has been done for i) new sewage sludge mono-/co-combustion plants (Paper II), and ii) the integration of treatment technologies, mainly anaerobic digestion, hydrothermal carbonization, and combustion, in an existing wastewater treatment plant (Paper III). Results from the analysis of sewage sludge management research (Paper I) show a narrow-focused perspective that often excludes inseparable aspects such as combination of economic consideration and advanced extraction technology. The investment viability of a new mono-/co-combustion of sewage sludge (Paper II) is highly conditional on heat, electricity, and fertilizer price, and external financial support is often a crucial requirement. Sewage sludge co-combustion with potassium-rich biomasses improves sewage sludge quality and forms usable ash as fertilizer without further need for phosphorus recovery technology. In this case, the economic feasibility of the process is independent of usable ash revenue, which stimulates a competitive selling price for the ash, thereby improving the marketing of sludge-based fertilizer. Avoided disposal costs of sewage sludge for a retrofitted wastewater treatment plant by introducing hydrothermal carbonization (Paper III) shows good economic feasibility while recovering phosphorus. Integrating anaerobic digestion, hydrothermal carbonization, and combustion may also improve investment incentives by improving energy outputs and phosphorus recovery. The economic feasibility is contingent on product (hydrochar, heat, electricity) prices and sensitive to added equipment costs, and costs for sludge transportation and disposal.
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| 13. |
- Bagheri, Marzieh
(författare)
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Sewage Sludge Treatment Scenarios: Techno-Economic Analyses of Energy and Phosphorus Recovery Focusing on Implementation Challenges
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Managing sewage sludge, an inevitable by-product of wastewater treatment processes rich in both contaminants and valuable resources, presents a dual challenge: ensuring pollution prevention by immobilizing or destroying contaminants, and facilitating resource recovery. Balancing these objectives is critical given the growing volumes of sewage sludge and the imperative to both protect the environment and recover valuable resources. The unknown risks of land application of sludge, the currently most common disposal method, make thermal conversion a promising alternative, as it enables energy recovery, the breakdown of potentially harmful organic compounds, and the formation of volume-reduced, sanitized products. Despite the technical feasibility, the commercial development of advanced recovery technologies has been slow. This thesis aims to expand knowledge on different sewage sludge treatment and disposal scenarios under varying conditions; thereby shedding light on implementation challenges, local opportunities, and the financial dynamics critical for phosphorus and energy recovery from the perspectives of wastewater treatment plants, investors, and policymakers. The aim is primarily addressed by performing techno-economic analysis of sewage sludge treatment scenarios, covering the entire sludge treatment process from sludge treatment to end products and disposal (Paper II-V). The techno-economic analysis is supplemented by a review of academic research on sewage sludge management from 1971 to 2019 (Paper I). Results from the analysis of sewage sludge management research (Paper I) show a narrow-focused perspective that often misses the broader, interconnected aspects of sewage sludge management, leading to research that, while detailed, fails to capture the complexity of the field. The investment viability of a new mono-/co-combustion plant for sewage sludge (Paper II) is highly conditional on heat, electricity, and fertilizer prices, and external financial support is often a crucial requirement. Cocombustion of sludge (in low ratios) with K-rich agricultural biomass requirement in and energy demand of a thermal dryer, and by yielding ash that contains phosphorus in a plant-available form. Utilizing existing heat facility (Paper III) and co-combustion to mitigate investment costs and energy demand in sludge management showed the potential to offer a cost-effective alternative to land application. However, the viability of co-combustion hinges on both a high heat market price (Paper II) and the proximity of affordable biomass resources (Paper III). Without these conditions, co-combustion may increase the financial burden of sludge management on wastewater treatment plants and policymakers. Retrofitting a wastewater treatment plant by integrating hydrothermal carbonization in sludge treatment (Paper IV), demonstrated good economic feasibility, primarily due to the avoided disposal costs, while also recovering phosphorus. However, integrating hydrothermal carbonization in a system designed for a thermal dryer may cause a significant reduction in electricity production.Given the high moisture content of sludge and the low market prices for fertilizer, the potential revenue from energy and phosphorus recovery is inadequate to solely drive investment in advanced sewage sludge treatment technologies (Papers II-V). This issue is exacerbated by the fact that most wastewater treatment plants are small in scale. Collaborative sludge management across neighboring wastewater treatment plants (Paper V) increases phosphorus recovery capacity and leverages economies of scale, fostering investment in advanced technology. This strategy presents a significant opportunity to lower the treatment costs and offers a competitive alternative to land application, while encompassing energy and phosphorus recovery into the sludge treatment.In conclusion, resource recovery and pollution prevention in sludge management is a complex task that necessitates simultaneous consideration of technical aspects, product quality, site-specific conditions, and profitability to ensure a comprehensive and viable approach. Leveraging local infrastructure and resources in sewage sludge management is crucial, highlighting the ecessity for strategies to be tailored to the local opportunities and limitations. Such an approach outperforms mono-combustion by eliminating the investment ensures that solutions are not only environmentally sustainable but also economically viable and socially acceptable.
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| 14. |
- Bauer, Torben
(författare)
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Can new treatment combinations make sewage sludge management more sustainable?
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Treated sewage sludge is often reused as a fertilizer but several European countries are phasing out this option due to concerns about harmful substances in the sludge. Valuables in the sludge should still be recycled so the removal of the pollutants is necessary. The technology in sewage sludge treatment remained nearly unchanged in the past century. Adapting traditional treatments and combining them with upcoming ones can be a way to separate substances in sewage sludge. This work discusses examples of how treatment methods can be combined and which potential these treatment combinations may have. New tools for system analyses need to be developed to allow the integration and adaption of treatments into existing infrastructure.
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| 15. |
- Bauer, Torben, et al.
(författare)
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Effects of the Different Implementation of Legislation Relating to Sewage Sludge Disposal in the EU
- 2020
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Ingår i: Detritus. - Padova : CISA Publisher. - 2611-4135. ; 10, s. 92-99
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Forskningsöversikt (refereegranskat)abstract
- The European Directive 86/278/EEC implemented in 1986 was a means adopted by the European Union to improve use of the valuables in sewage sludge by applying treated sludge on agricultural soils. To prevent an accumulation of pollutants, the Directive provided suggestions limiting concentrations of toxic elements in sewage sludge and agricultural soil. The Directive was implemented diversely throughout EU member states, with current national legislations only partly reflecting the initial intentions of the EU Directive from 30 years ago. This study demonstrates how the European Directive was implemented in three countries currently at different stages of replacing the agricultural application of sewage sludge with incineration (Netherlands, Germany and Sweden). Additionally, recent changes in the legislation with regards to the re-use and final disposal of sewage sludge in the three chosen member states are analysed. The aim was to investigate how each member state has solved the conflict between improvement of nutrient recovery from sludge and limitation of pollutants in agricultural soil. Based on this review, limit values are not necessarily reflected in application rates of sewage sludge in agriculture. Following changes in current legislation, phosphorus recovery will become a priority task. The recovery of other valuables from sewage sludge is currently not regulated in the legislation of the three member states investigated.
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| 16. |
- Bauer, Torben, et al.
(författare)
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Integration of hydrothermal carbonisation into Swedish sewage sludge treatment systems
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Usage pathways for sewage sludge are changing in Sweden but in contrast to other European countries Swedish legislation has no clear aim for phosphorus recovery from sewage sludge. Therefore, options like co-incineration and agricultural usage will become more important. Previous research identified hydrothermal carbonisation (HTC) as a potential treatment prior to incineration as it can help to dewater the sludge. Literature also discussed HTC as a pre-treatment for agricultural usage. This study investigates how HTC can be integrated into existing sewage sludge treatment systems using lifecycle assessments (LCA) of six archetype scenarios involving co incineration and agricultural usage of the solid product (hydrochar) of HTC. The results show that HTC can be advantageous as a pre-treatment to co incineration, especially when used before transporting the material to the incinerator. Utilizing the liquid product of HTC for biogas production reduces the climate change impacts but on the other hand increases ecotoxicity impacts. Utilizing hydrochar in agriculture as a soil amendment instead of incinerating it, does not show clear benefits over land application of sewage sludge, as hydrochar, in contrast to biochar from pyrolysis, decays in the soil within few years and is therefore not suitable for carbon sequestration.
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| 17. |
- Bauer, Torben
(författare)
-
Sustainable Sewage Sludge Management : Addressing Multidisciplinary Challenges
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This PhD thesis focuses on multidisciplinary challenges in sewage sludge management and how they can be addressed to increase sustainability. Sewage sludge is the residual from wastewater treatment. It contains both resources and contaminants making its management challenging. In the past sewage sludge was often used as a fertilizer in agriculture, a practice that is still used in several countries. Today, this practice gets questioned in Europe and especially in Sweden due to the presence of contaminants in the sludge. At the same time, the resources in the sludge get into a stronger focus as society moves towards a circular economy and food production should get more resilient in a world with geopolitical challenges. In sustainable sewage sludge management, the two goals of immobilising/destroying the contaminants and utilizing the resources in the sludge are combined. This thesis identifies challenges in various disciplines and provides potential solutions to make sewage sludge management more sustainable. The discussed challenges cover the following areas: legislation (EU and Sweden), perception of sewage sludge (Sweden), research on sewage sludge management (international), and combinations of treatment methods. Results show that outdated legislation in Sweden creates insecurities, while the negative perception of sewage sludge in Swedish society further aggravates these insecurities. Although technical solutions are available or under development, e.g., treatment combinations that can separate resources and contaminants, actors in Sweden remain hesitant due to the aforementioned insecurities. This thesis emphasizes that interdisciplinary approaches, and dialogues between different actor groups and society are essential. The multitude of challenges requires solutions that combine technical and non-technical approaches. Therefore, this thesis provides recommendations for more sustainable sewage sludge management practices, including updating legislation.
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| 18. |
- Brännvall, Evelina, et al.
(författare)
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Ageing of ashes in a landfill top cover
- 2011
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Ingår i: SARDINIA 2011. - Cagliari : CISA Publisher, Italy.
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Konferensbidrag (refereegranskat)abstract
- This paper is based on studies on the effects of accelerated ageing on refuse-derived-fuel (RDF) fly ashes, in experiments under controlled laboratory conditions, intended to derive models to predict the stability of RDF fly ashes used in a landfill liner and the mineralogi-cal changes that occur in them. A reduced factorial design was applied, followed by multivariate data analysis, to evaluate the effects of five factors — carbon dioxide (CO2) levels, temperature, relative air humidity (RH), time and the quality of added water — on mineral transformations within the ashes, and leaching behaviour. The pH values of these ash specimens ranged from 7.2 to 7.6, indicating advanced carbonation. Ageing decreased pH values from 12.4 to 7.2, conse-quently affecting the leaching behaviour of most chemicals measured in the leachates. Levels of Ba, Ca, Cl, Cr, Cu, Pb, K and Na decreased over the study period while those of Mg, Zn and SO4 increased. Clay minerals could not be detected neither in fresh nor in aged ashes. However, geo-chemical modelling indicated that such minerals may precipitate.
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| 19. |
- Brännvall, Evelina, et al.
(författare)
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Changes of fly ash properties during the ageing
- 2015
-
Ingår i: Journal of environmental engineering. - 0733-9372 .- 1943-7870. ; 141:5
-
Tidskriftsartikel (refereegranskat)abstract
- Aging of refuse-derived fuel (RDF) fly ashes was investigated in a long-term laboratory experiment. Aging affected the chemical stability of RDF fly ash in terms of leaching behavior, ANC, and mineralogical transformations. The design of experiment model evaluation showed that the use of RDF ashes in a top cover liner construction has the following advantages: most of the investigated hazardous elements like Pb, Cl, Cr, Cu, etc., will not be released from the ashes, and their buffer capacity will increase with time. However, aging has the disadvantage that leaching of Zn and SO 4 is likely to increase. The multivariate data analysis of the coefficients of variation did not reveal any systematic errors in the performance of the experiment. However, batch leaching test not always reflect the real situation in the landfill top cover environment.
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| 20. |
- Brännvall, Evelina, et al.
(författare)
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Factors influencing chemical and mineralogical changes in RDF fly ashes during aging
- 2014
-
Ingår i: Journal of environmental engineering. - 0733-9372 .- 1943-7870. ; 140:3
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of aging should be considered for reliable long-term assessments of the environmental risks of the use of refuse-derived-fuel (RDF) fly ash as landfill top cover liner material. Mineral transformations that occur in RDF fly ash, and the effects of selected factors on these transformations, were studied on compacted fly ash specimens in an accelerated aging experiment using a reduced factorial design. Carbon dioxide concentration, temperature, relative air humidity, time, and the quality of added water were varied in six factor combinations. Acid neutralization capacity and leaching behavior were analyzed after four different periods of time. The results were evaluated with multivariate data analysis. A significant change in the acid neutralization capacity, a decrease in leaching of Ba, Ca, Cl − , Cr, Cu, Pb, K, and Na, and an increase in solubility of Mg, Si, Zn, and SO 2− 4 could be attributed to different aging conditions
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| 21. |
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| 22. |
- Brännvall, Evelina, et al.
(författare)
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Influence of accelerated ageing on acid neutralization capacity and mineralogical transformations in refuse derived-fuel fly ashes
- 2009
-
Ingår i: SARDINIA 2009. - Cagliari : CISA, Environmental Sanitary Engineering Centre. - 9788862650076
-
Konferensbidrag (refereegranskat)abstract
- This study is a part of a long-term collaboration between Telge Återvinning AB at Södertälje in South Sweden and Lulea University of Technology (LTU) in the Northern part of Sweden. Ashes and other industrial wastes used for landfill cover construction have been studied for several years. However, there is a need for further investigations with regard to the long-term mechanical and chemical stability of ash liners in landfill cover constructions. Long-term changes of ashes are investigated by laboratory studies on accelerated weathering (ageing) using experimental design. With regard to weathering, several stages can be identified: hydration and carbonation are well known processes while the processes surrounding the conversion of ash to clay minerals are less well known. There are a number of studies showing that the process of mineral transformation during the ageing of coal or MSWI ashes is quite similar to that of volcanic ashes in nature. Yet, the time frames are quite different: while volcanic ashes need several thousands of years for clay mineral development, there are evidences as well that e.g. clay illite is formed from glass phases in MSWI bottom ash after only 12 y or that clay like amorphous material can be formed in micro-scale throughout the surfaces of coal ash particles after 8 y of natural weathering (Zevenbergen et al., 1999; Zevenbergen et al., 1998). There are a lot of studies performed on rapid fly ash conversion into zeolites by hydrothermal alkaline treatment, the success of which strongly depends on alkaline conditions and the silica-alumina composition of the fly ash source (Inada et al., 2005). These results provide further support to the hypothesis that the observed rapid clay like mineral formation arose as a result of the initially high pH of ash, which promotes rapid dissolution of certain components of aluminosilicate glasses. Furthermore, in a long term perspective these aluminosilicates can transform into zeolites, smectites or halloysites dependent on the solution pH and leaching rate. Based on these studies on volcanic, coal or MSWI ashes we presume that refuse derived fuel (RDF) ashes, like those that are used in the Tveta landfill cover, will be subject to analogical weathering and mineral transformation processes.In order to investigate the mineral transformation in RDF fly ashes, a designed laboratory experiment was performed. A reduced factorial experimental design for accelerated ageing has been applied to evaluate the influence of five factors: carbon dioxide (CO2), temperature, relative air humidity, time and, quality of added water (Table 1). Table 1 Factors and levels tested in the reduced multivariate factorial design for the study of accelerated ageing of RFD fly ashesFactorLowMiddleHighCarbon dioxide, CO2 (%)Atmosphere (0.038)20*100Temperature, ºC5 3060Relative air humidity, Rh (%)3065100Time, months31022Water qualityDistilled -LeachateThe influence of these factors on mineralogical composition, leaching behaviour and acid neutralization capacity (ANC) is analysed and evaluated with the aid of multivariate data analysis. The MVDA modelling was performed with SIMCA-P+ 11.5 version program developed by Umetrics AB (Eriksson and Umetrics Academy, 2006). Principle component analysis (PCA) technique was used and presented in this paper. PCA is an interdependence model where all variables are analysed simultaneously as a single set in a data matrix X. Triplicates were tested for each factor combination. Sampling was performed after 3, 10 and 22 months of accelerated ageing. Mineral composition was analysed by X-Ray Diffraction (XRD). Acid neutralisation capacity was performed at 8.3 and 4.5 pH with 0.1 M HCl solution. The experimental set-up of accelerated ageing of RDF fly ashes is showed in Fig. 1. Preliminary evaluation of the mineral transformations in aged RDF fly ashes revealed that the carbonation process was not yet completed in the some of the specimens (Fig.2). This still caused high pH (pH=12.7) in the solution even though a calcite phase was found in all aged fly ashes. Multivariate data analysis confirmed that carbon dioxide affects the pH and ANC of fly ashes during ageing of RDF fly ashes. The specimens prepared with leachate water had higher ANC than the specimens with distilled water. The ANC8.3 was most influenced by 30 ºC temperature and 65 % relative humidity (ANC8.3 = 0.05 mmol/g) and this well corresponds to the results found in the literature. The ageing time factor has the highest influence on ANC4.5. A more detailed analysis of other mineral phases including clay-like minerals in aged fly ashes will be performed later.The results of this study will contribute to the better understanding of ash formation processes and improved possibilities to make beneficial use of ashes as an alternative to landfilling.Figure 1. Experimental set-up for investigations of the long-term behaviour of the ashes under different environmental conditions. Figure 2. XRD patterns of RDF fly ashes at different ageing conditions. a) N33, b) N71, c) N15, d) N85, and e) N51. The peaks are labelled A (anhydrite), C (calcite), E (ettringite), F (Friedel's Salt), Ge (gehlenite), H (halite), He (hematite), P (portlandite), Q (quartz), S (sylvite), V (vaterite).
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| 23. |
- Diener, Silvia, et al.
(författare)
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Accelerated carbonation of ashes and steel slags in a landfill cover construction
- 2008
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Ingår i: Proceedings of Second International Conference on Accelerated Carbonation for Environmental and Materials Engineering. - : University of Rome "La Sapienza". ; , s. 389-400
-
Konferensbidrag (refereegranskat)abstract
- Fly ash from biofuel incineration and slags from steel production were used in two full scale applications of cover constructions on municipal solid waste (MSW) landfills. The long-term stability of the cover materials is studied in a designed laboratory experiment. The impact of six environmental factors on accelerated carbonation is investigated over a period of three years. Leaching behaviour, acid neutralization capacity, mineral composition (XRD) and thermo gravimetrical behaviour (TG) are tested after different periods of ageing under different conditions. By now samples were taken after three and ten months of ageing. Multivariate data analysis was used for data evaluation. The results indicate the factors material, ageing time and carbon dioxide content of the atmosphere to be most relevant.
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| 24. |
- Diener, Silvia, et al.
(författare)
-
Accelerated carbonation of steel slags in a landfill cover construction
- 2010
-
Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 30:1, s. 132-139
-
Tidskriftsartikel (refereegranskat)abstract
- Steel slags from high-alloyed tool steel production were used in a full scale cover construction of a municipal solid waste (MSW) landfill. In order to study the long-term stability of the steel slags within the final cover, a laboratory experiment was performed. The effect on the ageing process, due to i.e. carbonation, exerted by five different factors resembling both the material characteristics and the environmental conditions is investigated. Leaching behaviour, acid neutralization capacity and mineralogy (evaluated by means of X-ray diffraction, XRD, and thermogravimetry/differential thermal analysis, TG/DTA) are tested after different periods of ageing under different conditions.Samples aged for 3 and 10 months were evaluated in this paper. Multivariate data analysis was used for data evaluation. The results indicate that among the investigated factors, ageing time and carbon dioxide content of the atmosphere were able to exert the most relevant effect. However, further investigations are required in order to clarify the role of the temperature.
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| 25. |
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| 26. |
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| 27. |
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| 28. |
- Diener, Silvia, et al.
(författare)
-
Mineral transformations in steel slag used as landfill cover liner material
- 2007
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Ingår i: SARDINIA 2007. - Cagliari : CISA, Environmental Sanitary Engineering Centre. - 9788862650038
-
Konferensbidrag (refereegranskat)abstract
- In Europe, 15.2 million tonnes of steel slags have been generated in 2004 (Euroslag, 2006) out if which almost 6 million tonnes came from electric arc furnace (EAF) steelmaking and secondary metallurgical processes. In the presented project from Luleå University of Technology, two types of EAF slag and one slag originating from secondary metallurgical processes named ladle slag are investigated. The chemical and physical properties of these slags have been studied in detail (Herrmann, 2006; Andreas et al., 2005). For utilising steel slags in the liner of a landfill cover the long-term stability of the minerals is of great importance. Therefore, the ageing of steel slag minerals is evaluated with the help of a laboratory experiment. Particularly, the research questions, the experimental set-up and the methodology are presented. The present paper is part of a research project of the Division of Waste Science and Technology at Luleå University of Technology, Sweden in cooperation with Uddeholm Tooling AB, Hagfors municipality and MiMeR (Mineral and Metal Recycling Research Centre). It is investigated if steel slags are stable as a landfill cover liner material. The long-term stability is evaluated by determining the factors influencing the mineralogy of the slags and possible mineral transformations through ageing under the environmental conditions in a liner. The experiment includes two similar types of EAF slag and one ladle slag. Each steel slag sample is made by mixing 50% EAF slag and 50% ladle slag, addition of water and compaction. The specimens are stored in boxes under different atmospheric conditions. A reduced multivariate design has been chosen to determine the impact of different factors on the slag mineralogy. The factors that are varied in the experiment are relative humidity, carbon dioxide and temperature of the atmosphere surrounding the slag material as well as ageing time and the quality of the water used for sample making (see table 1). Table 1. Factorial design for ageing experiment of steel slagsLowMiddleHighRelative humidity30% -100%Carbon dioxide content0.036 (air)20 % * 100 %Temperature5 °C30 °C60 °CTime 1 month6 months1 yearWater quality destilled water -LeachateThe ageing of minerals is expected to initiate mineral transformations in steel slags. Primary phases will alter into secondary mineral phases. Changes in mineralogy can influence the stability of the liner. To evaluate mineralogy and properties of the aged steel slag, different analyses will be performed after the storage time of the specimens. X-ray diffraction and scanning electron microscopy as well as shear strength, acid neutralisation capacity and cation exchange capacity will be included. A possible mineral transformation for an alkaline material as steel slags can be the reaction of calcium ions from calcium silicates with the carbon dioxide resulting in the precipitation of calcium carbonate. Through this carbonation reaction, the transport of carbon dioxide into the bulk of the specimen could be hindered by the reaction products. Therefore, surface morphology can influence mineral transformations. First results and evaluations will be presented at the conference. REFERENCES Andreas L., Herrmann I., Lidstrom-Larsson M. & Lagerkvist A. (2005) Physical properties of steel slag to be reused in a landfill cover, Sardinia 2005, Tenth International Waste Management and Landfill Symposium, S. Margherita di Pula, Cagliari, Italy; 3 - 7 October 2005Euroslag (2006) Legal status of Slags. Position Paper. January 2006. The European Slag Association - EUROSLAG. Duisburg, Germany.Herrmann I. (2006). Use of Secondary Construction Material in Landfill Cover Liners. Licentiate Thesis. Luleå University of Technology, Sweden.
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| 29. |
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| 30. |
- Herrmann, Inga, et al.
(författare)
-
Hydraulic conductivity of fly ash : sewage sludge mixes for use in landfill cover liners
- 2009
-
Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 43:14, s. 3541-3547
-
Tidskriftsartikel (refereegranskat)abstract
- Secondary materials could help meeting the increasing demand of landfill cover liner materials. In this study, the effect of compaction energy, water content, ash ratio, freezing, drying and biological activity on the hydraulic conductivity of two fly ash - sewage sludge mixes was investigated using a 27-1 fractional factorial design. The aim was to identify the factors that influence hydraulic conductivity, to quantify their effects and to assess how a sufficiently low hydraulic conductivity can be achieved. The factors compaction energy and drying, as well as the factor interactions material×ash ratio and ash ratio×compaction energy affected hydraulic conductivity significantly (α = 0.05). Freezing on 5 freeze-thaw cycles did not affect hydraulic conductivity. Water content affected hydraulic conductivity only initially. The hydraulic conductivity data were modelled using multiple linear regression. The derived models were reliable as indicated by R2adjusted values between 0.75 and 0.86. Independent on the ash ratio and the material, hydraulic conductivity was predicted to be between 1.7 × 10-11 m s-1 and 8.9 × 10-10 m s-1 if the compaction energy was 2.4 J cm-3, the ash ratio between 20 and 75 % and drying did not occur. Thus, the investigated materials met the limit value for non-hazardous waste landfills of 10-9 m s-1.
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| 31. |
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| 32. |
- Herrmann, Inga, et al.
(författare)
-
Reuse of steel industry slag in a landfill top cover
- 2006
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Ingår i: Abstract proceedings of the 4th Intercontinental Landfill Research Symposium, [June 14th to 16th 2006, Gällivare, Sweden]. - Luleå : Luleå tekniska universitet. ; , s. 88-89
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 33. |
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| 34. |
- Herrmann, Inga, 1978-, et al.
(författare)
-
Steel slag used in landfill cover liners: laboratory and field tests
- 2010
-
Ingår i: Waste Management & Research. - 0734-242X .- 1096-3669. ; 28:12, s. 1114-1121
-
Tidskriftsartikel (refereegranskat)abstract
- Stricter rules for landfilling within the EU have led to the closure of many landfills and a need for large amounts of cover liner materials. Therefore, the potential utilization of mixtures of electric arc furnace slag (EAFS) and ladle slag (LS), which are currently deposited in landfills, as a material for use as landfill liner was investigated. Laboratory analyses showed the mixtures to have similar compression strength to that of high-strength concrete and low hydraulic conductivity (<10-11 m s-1 in some cases). However, both their hydraulic conductivity and compaction properties were strongly affected by the time between adding water to the mixtures and compacting them (tests showed that a delay of 24 h can lead to an increase in hydraulic conductivity, so it should be compacted as soon as possible after mixing the material with water). In addition, the performance of a cover liner constructed using EAFS and LS was studied in a 2-year field trial on a landfill for municipal solid waste, in which the average amount of leachate collected from ten lysimeters was only 27 L m-2 year-1, easily meeting Swedish criteria for the permeability of covers on non-hazardous waste landfills (≤50 L m-2 year-1). Thus, the material seems to have promising potential for use in barrier constructions.
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| 35. |
- Klausing, Benjamin, et al.
(författare)
-
Auswertung zweier reststoffbasierter Deponieabdeckungen
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Large amounts of material will be needed to install covers on closed landfill constructions due to the application of EU landfill directive 1999/31/EC. Approximately 1 million t of ashes are produced in Sweden each year. The interest in substituting conventional construction materials for landfill covers by alternative materials increases by the possibility to implement advantages, such as saving natural resources and economic benefits, using SCM. But to use SCM advantageous for the intended purpose, additional problems compared to the use of conventional materials have to be solved, such as availability, storing, preparation, planning and the construction process itself. Thorough investigations and experiments to characterize the used materials are a necessity. At Tveta Landfill in Södertälje field investigations are performed concerning different cover construction designs. During an excavation in 2007 samples from the different layers of the cover of two test fields were collected. In this study the development of the cover constructions is investigated focusing the mechanical and chemical stability of the cover constructions. During the investigations the bulk density, WHC and total composition of the material were analyzed and a diffusion test was performed. No negative development of the mechanical properties of the material due to ageing processes could be determined. The results of the analyses show that the construction process itself influences the future mechanical and chemical conditions of the cover construction. For example, the delayed covering of the protection layer of area 1 by the vegetation layer resulted in displaced concentrations for most considered components within the solid matter.The comparison of solid matter content and leaching behaviour before installation and after excavation after two and four years, respectively, indicate a trend to decreasing concentrations for most of the concerned components. The trend is only weak due to the short time the material was in place and because the amount of water that percolated through the layers was reported to be small. For some components enrichment especially in the protection layer of area 4 was determined. It could be shown that this enrichment is caused by the superimposed vegetation layer material, which contains high concentration levels for some elements. The transport path of these components leading to a contamination of the other layers by leaching could also be disclosed. The leaching behaviour of the fly ash used in area 4 was studied in a diffusion test using leachate from the protection layer as a way to understand the influence of different layers on each other. Moreover, the comparison of the results from this test with another diffusion test using distilled water reveals different behaviour depending on the used leachant. The diffusion occurs in the initial phase of the experiment for the concerned diffusion controlled components influenced by the leachate of the protection layer. A difference in the leached amounts could also be noticed. The stabilization of the mineral liner due to the formation of clay minerals could not be proved analytically, but the precursors reported to be necessary for this process could be determined.Leaching was found to have the main impact on the stabilization of the cover construction, causing the reduction of component concentrations and the approach to an equilibrium state between the cover and its environment. It was shown that the influence of leaching emissions on the environment is controllable. A risk for the environment was determined by the contaminated vegetation layer of area 4, hence uncontrolled emissions of components into the environment by plants and animals may occur.As a result of this study it is shown that the implementation of SCM is possible. Whether constructing with SCM is successful or not strongly depends on anticipatory planning and the design, the knowledge of the materials properties, their development over time and their interactions.
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| 36. |
- Kumpiene, Jurate, et al.
(författare)
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Carbon speciation in ash, residual waste and contaminated soil by thermal and chemical analyses
- 2011
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 31:1, s. 18-25
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Tidskriftsartikel (refereegranskat)abstract
- Carbon in waste can occur as inorganic (IC), organic (OC) and elemental carbon (EC) each having distinct chemical properties and possible environmental effects. In this study, carbon speciation was performed using thermogravimetric analysis (TGA), chemical degradation tests and the standard total organic carbon (TOC) measurement procedures in three types of waste materials (bottom ash, residual waste and contaminated soil). Over 50% of the total carbon (TC) in all studied materials (72% in ash and residual waste, and 59% in soil) was biologically non-reactive or EC as determined by thermogravimetric analyses. The speciation of TOC by chemical degradation also showed a presence of a non-degradable C fraction in all materials (60% of TOC in ash, 30% in residual waste and 13% in soil), though in smaller amounts than those determined by TGA. In principle, chemical degradation method can give an indication of the presence of potentially inert C in various waste materials, while TGA is a more precise technique for C speciation, given that waste-specific method adjustments are made. The standard TOC measurement yields exaggerated estimates of organic carbon and may therefore overestimate the potential environmental impacts (e.g. landfill gas generation) of waste materials in a landfill environment.
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| 37. |
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| 38. |
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| 39. |
- Kumpiene, Jurate, et al.
(författare)
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Utilisation of chemically stabilized arsenic-contaminated soil in a landfill cover
- 2013
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 20:12, s. 8649-8662
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to determine if an As-contaminated soil, stabilized using zerovalent iron (Fe0) and its combination with gypsum waste, coal fly ash, peat, or sewage sludge, could be used as a construction material at the top layer of the landfill cover. A reproduction of 2 m thick protection/vegetation layer of a landfill cover using a column setup was used to determine the ability of the amendments to reduce As solubility and stimulate soil functionality along the soil profile. Soil amendment with Fe0 was highly efficient in reducing As in soil porewater reaching 99 % reduction, but only at the soil surface. In the deeper soil layers (below 0.5 m), the Fe treatment had a reverse effect, As solubility increased dramatically exceeding that of the untreated soil or any other treatment by one to two orders of magnitude. A slight bioluminescence inhibition of Vibrio fischeri was detected in the Fe0 treatment. Soil amendment with iron and peat showed no toxicity to bacteria and was the most efficient in reducing dissolved As in soil porewater throughout the 2 m soil profile followed by iron and gypsum treatment, most likely resulting from a low soil density and a good air diffusion to the soil. The least suitable combination of soil amendments for As immobilization was a mixture of iron with coal fly ash. An increase in all measured enzyme activities was observed in all treatments, particularly those receiving organic matter. For As to be stable in soil, a combination of amendments that can keep the soil porous and ensure the air diffusion through the entire soil layer of the landfill cover is required.
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| 40. |
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| 41. |
- Kylefors, Katarina, et al.
(författare)
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A comparison of small scale pilot-scale and large-scale tests for predicting leaching behaviour of landfilled wastes
- 2003
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Ingår i: Waste Management. - 0956-053X .- 1879-2456. ; 23:1, s. 45-59
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Tidskriftsartikel (refereegranskat)abstract
- Landfills generate emissions over long periods, often longer than a lifetime. The longest lasting emission is leachate. In order to estimate the future requirements for leachate treatment, different kinds of leaching tests may be applied. In this paper, shaking leaching tests (SLT), landfill-simulator leaching tests and a field-cell leaching test performed with ash, municipal solid waste (MSW) and MSW+ash are evaluated. The tests are compared and the factors influencing leaching are identified and discussed. The factors are: liquid to solid (L/S) ratio, water withdrawal, recirculation rate, presence or absence of biological processes, size of particles, duration of experiment, temperature and pre-treatment of the waste. The presence of biological processes has the greatest impact on leaching and is the main reason why SLT is less useful for long-term predictions. The landfill simulator tests were found to be useful for several different kinds of predictions. However, they are not reliable for predicting the L/S required for reaching a certain concentration. The possibilities for reliable long-term predictions would be facilitated by a better knowledge of the influence of various factors on leaching. Such an increased knowledge would make it possible to enhance waste stabilisation in leaching tests as well as in full-scale landfills.
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| 42. |
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| 43. |
- Lindmark, Johan, et al.
(författare)
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Pre-treatment of Substrate for Increased Biogas Production
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The full biogas potential of most organic material cannot be exploited with today’s technology. The complex structures of the organic materials are broken down too slowly and the nutrients cannot become biologically available during the relatively short retention time of most digesters. This means that a lot of the bound energy in the organic material leaves the biogas plant with the liquid digestate. There is a possibility to increase the efficiency of the process by pre-treating the material before digestion. This paper explores a pre-treatment of ley crop silage using electrical fields, known as electroporation (EP). Different settings of the EP equipment were tested and the results were analysed using a batch digestion setup. The results from the experiments show that there is a possibility to double the biogas production at typical retention times of a CSTR. The energy balance of the EP equipment suggests that the pre-treatment yield is around 2-6 times larger than the energy input to the process, i.e. energy in the form of methane.
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| 44. |
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| 45. |
- Marklund, Erik, 1985-, et al.
(författare)
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Characterization and mechanical separation of organic matter in construction and demolition waste fines
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Construction and demolition waste (CDW) amounts to a large fraction of produced waste. 37 %-58 % was found to be fines. Wood is a common building material in the Nordic countries, so CDW fines have a high organic content. Typically, CDW fines are landfilled, but due to the high content of total organic carbon (TOC), this is not allowed. In order to investigate potential treatments or uses of these fines, they were characterized, with focus on their organic content. The potential for mechanical separation was tested by sieving and by float-sink separation in water. The organic content is higher in the larger and lighter particles. Mechanical separation by particle size using a 10 mm screen is not likely to consistently produce an under sieve fraction with low TOC content (<10 %). After float-sink separation, the sink fraction still contains 9-42% volatile solids (VS). However, based on tests of biogas potential and respiration activity, the biological activity of the sink fraction can be considered low. This is confirmed by thermogravimetric analysis, showing an organic carbon (OC) content of only 1-2 %. The TOC (measured by CO2 formation) is up to nine times higher than the OC, indicating that the TOC is not a reliable assay to measure organic carbon. Further studies will show if screening up to 10 mm, or screening in combination with density separation can yield a low TOC fraction for landfilling.
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| 46. |
- Marklund, Erik, 1985-, et al.
(författare)
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Float-sink separation of C&D waste : a case of treatment oriented waste characterization
- 2017
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Ingår i: Sixteenth International Waste Management and Landfill Symposium. - Italy.
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Konferensbidrag (refereegranskat)abstract
- Landfilling and waste incineration are two major waste management options. However, some wastes can,due to their carbon content,be unsuitable for neither of these systems. Therefore, there is aneed for methods to remove organic carbon from wastes. One of these wastesis the construction and demolition fines. In this paper, we investigate using water for separating the waste by density, to see if this is a suitable method for separating carbon-containingmaterials, both in lab and field scale tests. Results show that halfof the carbon (measured as volatile solids) can be separated. However, this method cannot be said to reliably produce a sink fraction that is suitable for landfilling, as it still contains too much organic materials.
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| 47. |
- Marklund, Erik, 1985-, et al.
(författare)
-
Float-sink separation of construction and demolition waste fines
- 2018
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Ingår i: Detritus. - Padova, Italy : CISA Publisher. - 2611-4135. ; 3, s. 13-18
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Tidskriftsartikel (refereegranskat)abstract
- Landfilling and waste incineration are two major waste management options. However, due to their carbon content, some wastes may be unsuitable for these systems. Therefore, methods capable of removing organic carbon from wastes should be identified. One of these wastes is represented by construction and demolition fines. In this paper, we investigate the use of water in separating the waste by density, to verify the suitability of this method in the separation of carbon-containing materials, both in lab and field scale tests. The results obtained show that half of the carbon (measured as volatile solids) can be separated. However, this method fails to reliably produce a sink fraction suitable for landfilling, as it continues to be characterized by an excessively high organic material content.
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| 48. |
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| 49. |
- Marklund, Erik, 1985-
(författare)
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Treatment oriented waste characterization
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- New types of materials and products are developed every day, and subsequently, new types of wastes. At the same time, new regulations are put forth to protect human health and the ecosystems from the negative impacts of wastes. Often, the waste management industry is responsible to deal with these problems, and hence, good knowledge about wastes and their treatment is crucial. Waste is normally characterized in order to determine a treatment; however, this usually implies a known treatment method.This thesis aims to provide a structured approach about how to describe different treatments, and to provide guidance on how to characterize wastes in a solution oriented manner. A distinction is made between two types of treatments: those based on separation processes and those based on transformation processes, as well as combinations of the two. Separation processes are common in mechanical treatment such as sieving or air-classification. Transformation processes are common in such treatments as shredding, electroporation, radiation treatment, and stabilization. Most treatments consist of both a transformation and a separation process, such as incineration, in which the organic carbon is oxidized (transformed) into CO2,that then is separated from the remaining solids. Other examples of combined processes are composting and anaerobic digestion.A framework is presented that enables a quantitative description of different waste treatments such as anaerobic digestion and incineration in the same context. All transformation processes take place in an environment that can be described by environmental factors such as temperature, pH, redox, radiation etc. By relating different treatments or observations to each other in an n-dimension matrix, it is possible to not only locate the currently known treatments, but also to locate unexplored areas, i.e. combinations of environmental factors that could be used to treat wastes in new ways.The addition of the n-dimensional framework to the general characterization model, together with the “top down” strategy for characterization provide valuable insights useful for dealing with new types of wastes in an efficient manner.
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| 50. |
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