The limited amount of freshwater is the most important challenge facing Egypt due to increasing population and climate change. The objective of this study was to investigate how climatic change affects the winter potato water footprint at the Nile Delta covering 10 governorates from 1990 to 2016. Winter potato evapotranspiration (ETC) was calculated based on daily climate variables of minimum temperature, maximum temperature, wind speed and relative humidity during the growing season (October–February). The Mann–Kendall test was applied to determine the trend of climatic variables, crop evapotranspiration and water footprint. The results showed that the highest precipitation values were registered in the northwest governorates (Alexandria followed by Kafr El-Sheikh). The potato water footprint decreased from 170 m3 ton−1 in 1990 to 120 m3 ton−1 in 2016. The blue-water footprint contributed more than 75% of the total; the remainder came from the green-water footprint. The findings from this research can help government and policy makers better understand the impact of climate change on potato crop yield and to enhance sustainable water management in Egypt’s major crop-producing regions to alleviate water scarcity.

Lack of land for waste disposal is one of the main problems facing urban areas in developing countries. The Sulaimaniyah Governorate, located in Northern Iraq, is one of the main cities of the country in the Kurdistan Region, covering an area of 2400 km2. Currently, there is no landfill site in the study region that meets the scientific and environmental requirements, and the inappropriate dumping of solid waste causes adverse effects to the environment, economic and urban aesthetic. To overcome this phenomenon, it is crucial to suggest a landfill site, even in countries that recycle or burn their waste to protect the environment. Landfill sites should be carefully selected taking into account all regulations and other restrictions. The integration of geographic information systems and the multi-criteria decision analysis were used in this study to select suitable landfill locations in the region. To this end, thirteen layers prepared according to their importance including slope, geology, land use, urban area, villages, rivers, groundwater, slope, elevation, soil, geology, road, oil and gas, land use, archaeology and power lines. Two different methods (simple additive weighting and analytic hierarchy process) were implemented in a geographical information system to obtain the suitability index map for candidate landfill sites, where all these conditions satisfied the scientific and environmental criteria adopted in this study. The comparison of the maps resulting from these two different methods demonstrates that both methods produced consistent results.

Purpose: Normal soil washing leave high residual pollutant content in soil. The remediation could be improved by targeting the extraction to coarser fractions. Further, a low/high extraction pH and higher temperature enhance the pollutant removal, but these measures are costly. In this study, the utility of NaOH, oxalate-citrate (OC) and dithionite-citrate-oxalate (DCO) solutions for extracting of arsenic, chromium and zinc from contaminated soil were assessed and compared. In addition the effects of NaOH concentration and temperature on NaOH extractions, and those of temperature and pH on OC and DCO extractions, were evaluated. Materials and methods: A two-level, full-factorial design with a centre point was implemented. Two factors, concentration and temperature,were evaluated in NaOH extractions, and pH and temperature for OC and DCO solutions. In all cases, the extraction temperature was 20°C, 30°C and 40°C. The studied NaOH concentrations were 0.05, 0.075 and 0.1 M. The pH in OC solutions was 3, 5 and 7, and in DCO solutions, 4.7, 6.3 and 6.7. Water-washed and medium coarse soil fraction of arsenic, chromium and zinc contaminated soil was agitated for 15 min with the extraction solution. Results and discussion: In NaOH extractions, the temperature and (less strongly) NaOH concentration significantly affected As and Cr mobilisation, but only the latter affected Zn mobilisation. Both pH and temperature significantly (and similarly) influenced As and Cr mobilisation in OC extractions, while only the pH influenced Zn mobilisation. In contrast, the extraction temperature (but not pH) influenced As, Cr and Zn mobilisation in DCO extractions. Conclusions: For all extractants, mobilisation was most efficient at elevated temperature (40°C). None of the extractants reduced the soil's As content to below the Swedish EPA's guideline value. Use of DCO is not recommended because dithionite has a short lifetime and residual arsenic contents in DCO-extracted soil are relatively high. Instead, sequential extraction with NaOH followed by OC solutions (affording significant reductions in As, Cr and Zn levels in the soil with short extraction times) at 40°C is recommended.

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.

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.

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.

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.

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.

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.

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.

Secondary iron oxides formed in acid mine drainage, such as schwertmannite, are scavengers for metal(loid)s in mining environments. Increasing the understanding of the geochemical transformations of these minerals, as well as knowing how metal(loid)s affect these transformations, is crucial to ultimately predict the fate of these trace elements in acidic mine drainage and to minimize the potential environmental risk. In this study, transformation experiments have been conducted with a schwertmannite-rich sediment collected from a mining area and with synthesized schwertmannite as a reference material. The transformation of schwertmannite into goethite was studied as a function of the presence of arsenic, pH value, and redox conditions. Arsenic delayed the mineral transformation from pseudo-stable amorphous phases to more stable crystalline forms, especially at higher arsenic loadings and more acidic pH. Experiments in the presence of Fe(II) and ascorbic acid have proven that both components promote the mineral transformation or reductive dissolution of schwertmannite under anoxic conditions. The presence of arsenic reduced the catalytic effect of Fe(II), stabilizing the schwertmannite particles. On the other hand, arsenic had no effect on the reductive dissolution at these conditions when ascorbic acid was used as a reducing agent. © 2020 Elsevier B.V.

Increased temperatures and rainfalls will give more settlements and less bearing capacity in gravel roads, which will have implications for the forestry. Pulp mill fly ash without additives was used for stabilizing the road base of a low-volume gravel road. A two-year monitoring of the road was conducted, including measurements of achieved ash content, density, water infiltration capacity, and load bearing capacity. The results showed that the ash-stabilized sections performed better than conventionally upgraded sections and also achieved increased bearing capacity over time. Hydration of the fly ash increased the stiffness and decreased the permeability of the road base. The differences were more pronounced during spring thaw. Best performance was achieved in the section with thicker ash stabilized layer.

Rapport från DARE delprojekt regional framsyn. Etapp 1; scenarier och förslag på aktiviteter.Detta dokument är slutrapporten från den regionala framsynsprocessen som drevs 2008-2009 inom projektet DARE – Development Arena for Research and Entrepreneurship.Framsynen har verkat efter ett normativt och handlingsinriktat angreppssätt. Ledmotiv för processen har varit frågor som: Hur vill vi ha det? Varför är det inte så nu? Vad behöver vi göra nu och i framtiden? Regionen kan sägas kännetecknas av att den är rik på naturresurser och fattig på folk. Det är bakgrunden till de fokusområden som framsynen behandlat- Grönare näringsliv (hur kan nya och miljöeffektivare produkter och tjänsterutvecklas effektivare?)- Demografiutveckling (hur kan samhällsfunktionerna bestå med inverteradebefolkningspyramider och hur kan utvecklingen mot en åldrande befolkningvändas?)Lite tvärs över båda frågorna ovan hamnar ett annat fokus; regionens attraktivitet. Inom detta område har en ung framsyn genomförts med deltagare från olika delar av Norrbotten.Framsynen har gått steg för steg genom visioner, analys av framgångsfaktorer, scenarieskapande, förslag på åtgärder och prioritering av dessa. Under genomförandet har det uppstått ett antal avknoppningar i form av t ex nya samarbeten och projekt. Ett av de sistnämnda var den unga framsynen som genomfördes med finansiering av Norrbottens läns landsting.Bland de prioriterade förslagen som redovisas i denna rapport dominerar olika aktiviteter för att knyta samman olika aktörer och grupper inom regionen och på så sätt göra mer av mindre. Många av förslagen visar regionala aktörers förväntningar på universitetens roll i den regionala utvecklingen och markerar ett intresse av tätare samverkan meduniversiteten. Förslagen berör alla verksamheter inom universiteten, såväl utbildning, forskning och förvaltning. Bland de prioriterade förslagen finns:• Stimulera gröna affärs och teknikutvecklingsallianser för regionens småföretag• Stimulera ”den lille forskaren” – en modell för småföretagens forskarkollektiv• Utred grönare näringsliv som gemensamt profilområde för regionens universitet• Stärk företagsnyttig forskning & utvecklingsinsatser kring ”age management”• Etablera ett ”integrationsnätverk” för universitetens studenter & det regionalasamhället• Utveckla dialogen mellan universiteten & avnämargrupper i utvecklingen avutbildningar • Skapa regionalt utvecklingslab för bättre samverkan mellan universiteten ochomgivande samhälleInom DARE-projektet kommer nu det material som utvecklats inom framsynsprocessen att användas för utveckling av samverkan inom universiteten, mellan universiteten och med andra intressenter av den regionala utvecklingen, inte minst då de som deltagit i framsynen.

Phosphorus (P) is a finite, non-renewable resource that is a critical component of fertilizers; therefore, recovering P from municipal wastewater can provide an alternative sustainable source of this nutrient. This work analyses economic impacts and greenhouse gas emissions of P recovery in Swedish municipal wastewater treatment plants. The study examines different scenarios, including P recovery technologies in individual plants and hubs, and considers various P-rich streams (supernatant, sludge, and ash) in plants, different plant sizes, and multiple sludge management strategies such as land application, incineration, and hydrochar production, under current market conditions. The goal is to identify and offer solutions tailored to local conditions, addressing both technical opportunities and strategies to reduce costs.

The results show varying recovery rates: 5 % from supernatant, 36–65 % from sludge, and 17 % from sludge ash relative to total P in wastewater. Despite technical feasibility, P recovery costs are not covered at current market prices of P, indicating a lack of financial incentive, especially for smaller treatment plants. The least expensive recovery method costs about 7 k€/t P for ash, compared to 30–187 k€/t P for supernatant, however with the latter coming with the co-benefit of mitigated greenhouse gas emissions. The emissions from studied plants range from 84 to 123 kt CO2 eq (CO2 equivalent) for supernatant, 94–141 kt CO2 eq for sludge, and 75–102 kt CO2 eq for ash among different P recovery methods. Comparatively, P recovery methods from supernatant showed the lowest emissions, while the lower emissions range for ash is due to the consideration of fewer plants. Developing hub networks and converting sludge into products like hydrochar are crucial for attracting investments, enhancing P recovery, and leveraging economies of scale. Results highlight the urgency for localized strategies and proactive policy interventions to reconcile economic and environmental objectives in P recycling. Furthermore, P recovery from wastewater treatment plants, although more resource-intensive than mineral fertilizer, promotes circularity in the food chain and mitigates the risk of eutrophication.

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.

As Sweden’s northernmost city, Kiruna has very particular demands for its sewage sludge treatment. This study tests hydrothermal carbonisation (HTC) as a treatment option for Kiruna to stabilize the sewage sludge, facilitate its transport by volume reduction and prepare the sludge for recovery of resources. The study consists out of an experimental part and a lifecycle assessment (LCA) development, which also gives options to use the results in other LCA scenarios incorporating HTC. Preliminary results show that HTC is a treatment that can fulfil Kiruna’s demands and that an optimization of the treatment’s settings can greatly increase the efficiency and effectiveness of the HTC treatment.

This study uses a new approach for the recycling of plant nutrients by co-digesting sewage sludgewith fly ash from a wood combustion. Sewage sludge and fly ash both are enriched with nutrientsof the wastewater resp. wood, which makes these products an enhanced source for recycledfertilizers. The effects of the ash addition to the anaerobic digestion are studied in several labscale experiments including effects on the gas production and microbial activity. Following that,the fertilizing qualities of the digestate are evaluated by plant growth experiments. The resultsshow that the fertilizing qualities of the digested sludge were improved by the ash addition.Next to this, gas production results show that the methane production was not affected by theash addition, while the total gas release was reduced. The sulphur addition by the ashstimulated sulphate reducing bacteria. The sulphate reducing bacteria did not markedly inhibitthe methanogens.

Carbonate precipitation is known to occur in landfilled ashes and is often reported as a problem because of the precipitates tendency to clog drains and other leachate transport facilities. The Up-take of carbon dioxide by alkaline wastes and leachates will influence their properties e.g.; The hydraulic and gas conductivity of solid wastes will decrease as carbonates precipitate in the pores of the waste. The pH will change towards neutral values as carbonates form changing the mobility of metals and other elements A neutral pH will also allow biological reactions to act on the waste, especially if the waste contain organic material as e.g. ashes often do. Adding carbon dioxide to wastes can thus be a cheap and powerful treatment, yielding a less hazardous waste.

A questionnaire survey was carried out in 4 European countries to gather end-user's perceptions of using plants from phytotechnologies in combustion and anaerobic digestion (AD). 9 actors of the wood energy sector from France, Germany and Sweden, and 11 AD platform operators from France, Germany and Austria were interviewed. Questions related to installation, input materials, performed analyses, phytostabilization and phytoextraction. Although the majority of respondents did not know phytotechnologies, results suggested that plant biomass from phytomanaged areas could be used in AD and combustion, under certain conditions. As a potential advantage, these plants would not compete with plants grown on agricultural lands, contaminated lands being not suitable for agriculture production. Main limitations would be related to additional controls in process' inputs and end-products and installations that might generate additional costs. In most cases, price of phytotechnologies biomass was mentioned as a driver to potentially use plants from metal-contaminated soils. Plants used in phytostabilisation or phytoexclusion were thought to be less risky and, consequently, benefited from a better theoretical acceptance than those issued from phytoextraction. Results were discussed according to national regulations. One issue related to the regulatory gap concerning the status of the plant biomass produced on contaminated land.

This field study assessed the occurrence, event mean concentrations (EMCs), and removal of selected organic micro-pollutants (OMPs), namely, polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), nonylphenol (NP), 4-t-octylphenol (OP), and bisphenol A (BPA), in a gross pollutant trap (GPT)-biofilter/sand filter stormwater treatment train in Sundsvall, Sweden. The effects of design features of each treatment unit, including pre-sedimentation (GPT), sand filter medium, vegetation, and chalk amendment, were investigated by comparing the units' removal performances. Overall, the treatment train removed most OMPs from highway runoff effectively. The results showed that although the sand filter provided moderate (<50 % for phenolic substances) to high (50–80 % for PAHs and PHCs) removal of OMPs, adding a vegetated soil layer on top of the sand filter considerably improved the removal performance (by at least 30 %), especially for BPA, OP, and suspended solids. Moreover, GTP did not contribute to the treatment significantly. Uncertainties in the removal efficiencies of PAHs and PHCs by the filter cells increased substantially when the ratio of the influent concentration to the limit of quantification decreased. Thus, accounting for such uncertainties due to the low OMP concentrations should be considered when evaluating the removal performance of biofilters.

Urbant dagvatten kan innehålla per- och polyfluoralkylämnen (PFAS). Den nuvarande kunskapen omförekomst och transport av PFAS i reningsanläggningar för urbant dagvatten är fortfarande mycketbegränsad. Den här studien utvärderar förekomst, ackumulering och fördelning av 35 PFAS och derasprekursorer i filtermaterial och försedimenteringssteg i tjugo biofilteranläggningar som varit i drift längreän 7 år. C5-14,16 perfluoralkylkarboxylsyror (PFCA), C4,8,10 perfluoralkansulfonsyror (PFSA), metylperfluoroktansulfonamidättiksyra (MeFOSAA, en känd PFSA-prekursor) och okända C6-8 PFCAprekursorer var de vanligast förekommande ackumulerade föreningarna. PFAS och deras prekursoreråterfanns i alla djup i liknande förekomster och koncentrationer. Trots att halterna var något högre i detövre filterlagret och minskande med djup var dessa skillnader i regel inte statistiskt signifikanta. Det fannsingen tydlig skillnad mellan fördelningen av kort- och långkedjiga PFAS, trots att långkedjiga ämnen(PFSAs>C5 och PFCAs>C7) förväntades ha mindre mobilitet på grund av deras högre hydrofobicitet. Deövre 5 cm av biofiltren innehöll ofta de högsta föroreningsnivåerna av PFAS och okända prekursorer,men de fanns också djupare ner i filtret. I motsats till exempelvis metaller och PAHer, räcker det sannolikt inte att endast byta ut det översta filterlagret och/eller sediment på toppen av filtret för att avlägsnamer komplexa och mobila föroreningar som PFAS.

A process geomorphological investigation was started in 1999 to study present denudation rates and the mutual relationship of chemical and mechanical fluvial denudation in periglacial environments. Latnjavagge (9 km2; 950-1440 m a.s.l.; 68°20'N, 18°30'E) was chosen as a representative drainage basin of the arctic-oceanic mountain area in northernmost Swedish Lapland. Atmospheric solute inputs, chemical denudation, and mechanical fluvial denudation were analyzed. During the arctic summer field seasons of 2000, 2001, and 2002 measurements of daily precipitation, solute concentrations in precipitation, and in melted snow cores, taken before snowmelt, were recorded. In addition, solute and suspended sediment concentrations in creeks were analyzed, and bedload tracer movements were registered during the entire summer seasons (end of May until beginning of September). Results show a mean annual chemical denudation net rate of 5.4 t km-2 yr-1 in the entire catchment. Chemical denudation in Latnjavagge is less than one third of chemical denudation rates reported for Kärkevagge (Swedish Lapland) but seems to be at a similar level as in a number of other subarctic, arctic, and alpine environments. Mechanical fluvial denudation is lower than chemical denudation. Most sediment transport in channels occurs in the early summer season during a few days with snowmelt generated runoff peaks. The main sediment sources in the drainage basin are mobilized channel bed pavements exposing fines, ice patches/fields, and material mobilized by slush flows. The calculated mean mechanical fluvial denudation rate is 2.3 t km-2 yr-1 at the inlet of lake Latnjajaure, situated in Latnjavagge close to the outlet of the valley. A very stable vegetation cover and rhyzosphere in this environment mainly explain the low value. The mean mechanical fluvial denudation rate at the outlet of the entire Latnjavagge drainage basin, below lake Latnjajaure, is only 0.8 t km-2 yr-1. Both chemical and mechanical fluvial denudation show low intensity. The results from Latnjavagge support the contention that chemical denudation is a somewhat important denudational process in periglacial environments.

Unburned carbon (UC) in 21 combustion residues from solid biofuels has been examined using several methods of analysis (including LOI and TOC) as well as micro-Raman spectroscopy. The concentration of unburned carbon in the residues varied over an order of magnitude and in several samples accounted for about 10% of the ash mass. It was observed that TOC had a poor correlation to organic carbon, especially for fly ashes. LOI at all tested temperatures showed a better correlation than TOC to the organic carbon content, whereas the TOC is better correlated to elemental carbon. LOI550 gave a larger variation and a less complete mobilisation of unburned carbon than LOI at 750 or 975 °C did, but at the highest temperature metal oxidation was notably affecting the mass balance to the extent that some samples gained mass. For this reason, and of the temperatures tested, LOI750 seem to be the most stable indicator for organic remains in the incineration residuals. Most of the unburned carbon is elemental, and only slowly degradable, so the potential emissions of organic compounds from ashes should not be assessed by using a TOC test. The structure of the detected elemental carbon in UC is similar to that of activated carbon, which indicates a potentially large specific surface. This should be borne in mind when assessing the environmental impact of using ash for different purposes, including use as a construction material. Field studies are needed to verify the actual impact as it may depend on environmental conditions.

Early diagenesis of buried organic carbon in anoxic basins is dominated by microbial decomposition processes at temperatures and pressure slightly above ambient. Such conditions also describe decomposition of refuse in sanitary landfills and provide a reasonable model for systematic studies of their long-term geochemistry. For shorter time frame (decades), controlled high-solids anaerobic digestion systems provide a second model for investigation of optimized landfill systems. In this paper, we introduce both models through a series of preliminary mass-balances to develop a realistic overview of landfill processes, especially emphasizing carbon cycling in field settings over various time-frames. The terminal product of short-term anaerobic decomposition is methane--produced by methanogenic bacteria from some fraction of organic carbon landfilled. Laboratory studies of optimized landfill systems (ours and from the literature) indicate that, at best, 25-45% of organic carbon is converted to biogas carbon (methane and carbon dioxide); such percentages are rarely attained in field settings. Most of the methane is produced from cellulosic substrates while lignin substrates are recalcitrant, with lignin carbon entering sedimentary storage for time frames longer than the four decades of widespread landfilling experience in the U.S. and western Europe. Over time frames in excess of centuries, further transformations via kerogen pathways are possible but highly speculative. Certainly, exhumation of old refuse at archeologic sites indicates that organic carbon preservation can be documented for at least one or two millenia. From controlled incubation of unamended field samples and from field studies of net methane emissions, it is clear that rates of methane production and consumption both vary of several orders of magnitude in field settings; their dynamic are rapid and complex spatially and temporally. Unraveling these dynamics is necessary to suggest the overall relevance of these engineered anoxic basins to issues of atmospheric methane increases and terrestrial carbon storage.

Unlike organic contaminants, metal(loid)s do not undergo microbial or chemical degradation and persist for a long time after their introduction. Bioavailability of metal(loid)s plays a vital role in the remediation of contaminated soils. In this review, the remediation of heavy metal(loid) contaminated soils through manipulating their bioavailability using a range of soil amendments will be presented. Mobilizing amendments such as chelating and desorbing agents increase the bioavailability and mobility of metal(loid)s. Immobilizing amendments such of precipitating agents and sorbent materials decrease the bioavailabilty and mobility of metal(loid)s. Mobilizing agents can be used to enhance the removal of heavy metal(loid)s though plant uptake and soil washing. Immobilizing agents can be used to reduce the transfer to metal(loid)s to food chain via plant uptake and leaching to groundwater. One of the major limitations of mobilizing technique is susceptibility to leaching of the mobilized heavy metal(loid)s in the absence of active plant uptake. Similarly, in the case of the immobilization technique the long-term stability of the immobilized heavy metal(loid)s needs to be monitored.

Poly- and perfluoroalkyl substances (PFASs) are synthetic chemicals, which are introduced to the environment through anthropogenic activities. Aqueous film forming foam used in firefighting, wastewater effluent, landfill leachate, and biosolids are major sources of PFAS input to soil and groundwater. Remediation of PFAS contaminated solid and aqueous media is challenging, which is attributed to the chemical and thermal stability of PFAS and the complexity of PFAS mixtures. In this review, remediation of PFAS contaminated soils through manipulation of their bioavailability and destruction is presented. While the mobilizing amendments (e.g., surfactants) enhance the mobility and bioavailability of PFAS, the immobilizing amendments (e.g., activated carbon) decrease their bioavailability and mobility. Mobilizing amendments can be applied to facilitate the removal of PFAS though soil washing, phytoremediation, and complete destruction through thermal and chemical redox reactions. Immobilizing amendments are likely to reduce the transfer of PFAS to food chain through plant and biota (e.g., earthworm) uptake, and leaching to potable water sources. Future studies should focus on quantifying the potential leaching of the mobilized PFAS in the absence of removal by plant and biota uptake or soil washing, and regular monitoring of the long-term stability of the immobilized PFAS.

Bentonit är en starkt vattenupptagande och svällande naturlig lera med låg vattengenomsläpplighet. Huvudkomponenten är mineralet montmorillonit, som tillhör gruppen smektiter och som ger bentoniten dess unika egenskaper. Syftet med uppdraget är att söka identifiera vilka mekanismer och faktorer som kan vara begränsande för funktionen på kort och lång sikt hos tätskikt innehållande bentonitmattor samt blandningar av bentonit och andra material. I rapporten ges underlag för projektering, utformning och drift av deponier med tätskikt innehållande bentonit. Där redovisas också tre fallstudier från Högbytorp, Löt och Tveta.

Ashes have properties that can be exploited in various applications, e.g. some ashes can be used in the construction of barriers in a landfill final top cover. A landfill top cover is a multilayer construction that protects the environment in several ways, for instance hindering gas emissions from the landfill body and water infiltration into the waste.Impervious natural materials like clay, synthetic materials like geomembranes or bentonite carpets, geosynthetic clay liners or combinations of such materials are commonly used in landfill top cover constructions. Since differential settlement may occur and the lifetimes of the synthetic materials are uncertain, it is advantageous to use thick mineral constructions. There is a great need for these materials, and substantial savings of resources can be made if alternative waste materials, like ashes, are used. Currently, ashes are either landfilled or used as construction materials. They are subject to weathering processes, including physical, chemical and mineralogical changes caused (inter alia) by fluctuations of temperature and humidity, atmospheric gases or acid rain. Ashes contain various potentially hazardous and non-hazardous chemical compounds. Therefore, precautions must be taken to avoid leaching of substances such as heavy metals into the surrounding environment. Mineral phases that are initially present and/or that form during the ageing are primarily responsible for the immobilization or leaching of diverse metals and salts. Newly formed mineral phases like clay minerals are of main interest, because of their very high cation exchange capacity, swelling and expansion properties.The conditions found in a landfill environment are likely to favour clay mineral formation. This thesis 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 mineralogical 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 their acid neutralization capacity (ANC) and leaching behaviour.Minerals (ettringite and hydrocalumite) promoting the immobilization of hazardous compounds were found in both fresh ash and ash aged under atmospheric conditions, but these minerals disappeared upon carbonation. The main phases in ash at 20% and 100% CO2 were calcite, gypsum/anhydrite and vaterite. The abundance of gypsum and anhydrite was directly related to the temperature at which ashes were aged. The major mineral phases detected in ashes aged under 20% CO2, 65% RH and 30°C (corresponding to conditions generally found in a landfill cover) were calcite and gypsum/bassanite. 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, consequently 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. No clay minerals were detected by XRD and SEM analysis in either fresh or aged ashes. However, geochemical modelling indicated that such minerals may precipitate. The modelling also indicated that clay minerals like saponite, vermiculite, chrysotile and hydrotalcite were likely to precipitate in most leachates from ash aged for 3, 10 and 22 months. Smectite, montmorillonite and illite may precipitate in leachates of ash aged for 31 months. The formation of smectite, montmorillonite and vermiculite would be advantageous due to their very high cation exchange capacities, which would favour the stabilization/immobilization of heavy metals in the mineral phases.

Municipal solid waste incineration fly ash is often landfilled or sent abroad for stabilization because it is considered a hazardous waste. These approaches to fly ash are both costly, and highlight the need for alternative and sustainable ash recycling. Both the needs of waste recycling and preservation of natural resources can be solved by using fly ashes as a secondary construction material and as soil fertilizer.Three types of fly ashes have been investigated in the laboratory experiments. Namely municipal solid waste incineration (MSWI), refuse-derived-fuel (RDF) and biofuel fly ashes. Factors influencing changes in chemical properties and mineralogical composition of RDF fly ash exposed to environmental conditions close to those that are found in a landfill top cover were evaluated in the accelerated ageing experiment. Element availability to leaching and plant uptake in soil amended with MSWI, biofuel fly ashes and biosolids was also evaluated.RDF fly ash exposed to the conditions found in a landfill top cover (20% CO2, 65% RH, 30°C T) lead to the chemical and mineralogical transformations that resulted in reduced leaching of most of the elements studied here. Only concentrations of Cl- in the leachates were an issue, because they still exceeded the leaching limit values; nevertheless the leaching of this element in aged ash decreased by 50% compared to fresh ash.Application of pelletized MSWI fly ash with biosolids on soil resulted in elevated total concentrations of As, Cd and Pb in soil (by 29%, 100% and 300%), but dissolved concentrations of these elements in soil pore water, except the As, were low as in the range of drinking water concentrations (98/83/EC). Furthermore, the concentrations of Cd and Pb in plant biomass were negligible regardless of the type of ash used.Based on the observations, RDF fly ash is considered as a suitable material to be used in a landfill liner. Whereas MSWI and biofuel fly ashes based on element availability for plants studies, could be considered suitable for land applications. But doses to be applied on soil should be adjusted to the type of ashes used to avoid accumulation of potentially toxic elements in soil over time.

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).

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

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.

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.

Increase of energy recovery from municipal solid waste by incineration results in the increased amounts of incineration residues, such as fly ash, that have to be taken care of. Material properties should define whether fly ash is a waste or a viable resource to be used for various applications. Here, two areas of potential fly ash application are reviewed: the use of fly ash in a landfill top cover either as a liner material or as a soil amendment in vegetation layer. Fly ashes from incineration of three types of fuel are considered: refuse derived fuel (RDF), municipal solid waste incineration (MSWI) and biofuel. Based on the observations, RDF and MSWI fly ash is considered as suitable materials to be used in a landfill top cover liner. Whereas MSWI and biofuel fly ashes based on element availability for plant studies, could be considered suitable for the vegetation layer of the top cover. Responsible application of MSWI ashes is, however, warranted in order to avoid element accumulation in soil and elevation of background values over time.