Incineration is a mainstream strategy for solid waste management in Sweden and all over the world. Improved knowledge and understanding about the distribution of trace elements (in ashes) during incineration, and how trace element partitioning respond to the changes in waste composition, are important in terms of combustion process optimization and plant efficiency. Moreover, determination of chemical association of trace elements in ashes are vital for avoiding environmental concerns and to promote possible reuse. In this study, partitioning of trace elements in ashes during incineration as function of input waste fuel and incineration technology was investigated. Further, chemical association of trace elements in resulting ashes was studied. An evaluation was also performed about feasibility of metal extraction from sulfidic mining waste and flotation tailings. Moreover, green liquor dreg (GLD) was tested with respect to stabilization of metals within the sulfidic mining waste. Findings showed that the total input of trace elements and chlorine affects the partitioning and increasing chlorine in the input waste caused increase in transfer of trace elements to fly ash especially for lead and zinc. Vaporization, condensation on fly ash particles and adsorption mechanisms play an important role for metal distribution. Firing mixed waste, especially biofuel mix, in grate or fluidized (CFB) boilers caused increased transfer into fly ash for almost all trace elements particularly lead and zinc. Possible reasons might be either an increased input concentration of respective element in the waste fuel, or a change in volatilization behavior due to the addition of certain waste fractions. Chemical association study for fly ashes indicated that overall, Cd, Pb, Zn, Cu and Sb are presenting major risk in most of the fly ashes, while in bottom ashes, most of elements are associated with stable fraction. Further, fuel type affects the association of elements in ashes. Chemical leaching of mining waste materials showed that sulfuric acid (under different conditions) is the best reagent to recover zinc and copper from sulfidic mining waste and also copper from flotation tailings. GLD indicates potential for metal stabilization in mining waste by reducing the metal mobility. Extraction methods could be applied to treat mining waste in order to meet the regulatory level at a specific mining site.Similarly stabilization/solidification  methods might be applied after leaching for recovery of metals.

Dagens linjära materialflöde leder till att nyttjandegraden av råvaror är låg, vilket tömmer ut världens resurser och mängden avfall ökar. Samtidigt skapar den ökande världsbefolkningen och världsekonomin ett större tryck på dagens resurser vilket inte är hållbart i längden. Genom att övergå till cirkulär ekonomi betraktas genererat avfall som en resurs, vilket ökar resursutnyttjandet i samhället. Byggbranschen är den verksamhet som genererar mest avfall i Sverige och stor del av den genererade mängden är träavfall. Idag energiutvinns i stort allt trä som kasseras och samtidigt sker ett ökat intresse för användning av materialet. Syftet med denna studie är att ta reda på hur och i vilken mängd träavfall från bygg- och rivningsarbete kan materialåtervinnas före energiutvinning.  Denna studie har kartlagt innehållet av tre containrar med träavfall från olika byggskeden; stomme, inredning och rivning. Kartläggningen utfördes med en sorteringsmetod som togs fram med hjälp av litteraturstudie och samtal med företag. De fyra möjliga sorteringsalternativ som togs fram under studien var Fingerskarvning / Återanvändning, Korslimmat trä, Lamellträ och Spånplattor.  Kartläggningen visar att fördelningen av träavfall varierar stort beroende på byggskede. Vid inredning är det mycket lastpallar, träskivor och reglar, detsamma gäller för stomme dock med en färre andel skivmaterial.   Vid maximal utdelning för stomme kan 19 % av träavfallet gå till Fingerskarvning / Återanvändning, Korslimmat trä  2 %,  Lamellträ 35 % och Spånplattor 100 %. Vid rivning fanns endast treetex och råspont vilket endast kan användas till Spånplattor. För inredning kan 12 % av träavfallet gå till Fingerskarvning / Återanvändning, Korslimmat trä 3 %, Lamellträ 10 % och Spånplattor 100 %. För stomme och inredning är resultatet baserat på en accepterad sortering för grånat och smutsigt virke för de två förstnämnda alternativen. Slutsatsen blir att allt träavfall kan användas till bättre alternativ än energiutvinning. Tills problemen med Korslimmat trä och Fingerskarvning / Återanvändning har lösts bör sortering ske utefter Lamellträ och Spånplattor. / Today's linear material flows leads to a low utilization of raw materials, which depletes the world's resources and the amount of waste increases. At the same time, the growing world population and world economy are creating more pressure on today's resources which is not sustainable in the long run. By converting to a circular economy, generated waste is regarded as a resource, which increases the utilization of resources in society. When it comes to generated waste, the construction industry is the biggest sector in Sweden and wood waste is a large part of the generated amount. Almost all wood waste today is combusted for energy recovery, and at the same time, there is an increased interest in using the material. The purpose of the study is to find out how, and in what amount, wood waste from construction and demolition work can be recycled before energy recovery.  This study has made a survey of the contents of three containers with wood waste from different construction stages; frame, fixing and demolition. The survey was carried out using a sorting method that was developed by studying literature and speaking with companies. The four possible sorting options that were found during the study were Finger jointed / Reuse, Cross-laminated timber, Laminated wood and Particleboard.  The survey shows that the distribution of wood waste varies greatly depending on the stage of construction. In the fixing stage, there are a lot of pallets, wooden boards and studs. The same goes for the frame stage, however, with a smaller proportion of board material. The maximum percentages for each of the sorting options for the frame stage are        19 % to Finger jointed / Reuse, Cross-laminated timber 2 %, Laminated wood 35 % and Particleboard 100 %. During demolition, there were only treetex and tongued and grooved board that can only be used for Particleboard. For the fixing stage, 12 % of the wood waste can go to Finger jointed / Reuse, Cross-laminated timber 3 %, Laminated wood 10 % and Particleboard 100 %. For the frame and fixing stage the results are based on an accepted sorting of gray and dirty wood for the two first mentioned sorting options.  The conclusion is that all wood waste can be used for better alternatives than energy recovery. Until problems with Cross-laminated timber and Finger jointed / Reuse have been solved, sorting should be based on Laminated wood and Particleboard.

Mercury contamination is an environmental issue with high priority due to its high toxicity. In addition to the atmospheric deposition, several lakes and rivers in Sweden are contaminated as a result from wood and pulp-fiber industries which stretches back 200 years. In Luleå, Sweden, a former groundwood industry, Karlshäll, has contributed to mercury pollution in the sediments of Notviken, a small bay connected to Luleå River and the Bothnian Sea, through release of process water. Industrial release of chemicals and wood pulp have resulted in a special type of sediment called fiber banks. The fiber banks contain high levels of organic matter and very little oxygen which contributes to large gas emissions from the fiber banks, gas ebullition. There is no generally accepted method for examining how mercury contaminants are spread through gas ebullition. The aim of this thesis was to review and find methods for that purpose. Through the literature review several types of methods emerged. Some of them were useful for measuring volumes of gas, whereas others were better designed for collecting gas and analysing it for concentration of elements. There are pros and cons with all methods but the one considered most useful in the case of Karlshäll would be Skarp’s method with active and passive sampling. The passive part includes setting up tents over the fiber bank with a known area, and then calculate the volumes of gas which migrate up through the water during a certain amount of time. The active sampling consists of stirring the fiber bank sediment with a stick and then gather the ascending gas bubbles in a Teflon-bag. The Teflon bag is thereafter sent to a chemical environmental laboratory for analysis of the concentration of elements. This method is the only one of the ones reviewed in this thesis which have been tested in Sweden at sites with gas- ebullition facilitated mercury transport. Although, Varadharajan et al’s (2011) sampling device with automation could be applicable if a long-term, high frequency monitoring programme would be used at Karlshäll. In addition, a sampling device with an integrated carbon-absorption-tube collector for trapping gaseous Hg would be beneficial if the samples can’t handle a long-distance transportation. Thus, the samples could be sent to a local laboratory instead. However, this type of device is not yet invented and would need further studies to develop. / Kvicksilverföroreningar är ett stort miljöproblem som räknas till de särskilt farliga ämnena vilka skall fasas ut för att nå miljömålet giftfri miljö. Föroreningarna är mycket giftiga för djur och miljö och det kvicksilver som redan spridits ansamlas och stannar kvar under lång tid i mark, vatten och biota. Utöver den atmosfäriska depositionen så är floder, älvar och sjöar i Sverige förorenade med kvicksilver, ett resultat av en 200-årig industri för tillverkning av pappersmassa och träfiber där kvicksilver varit en del i tillverkningsprocessen.  I Luleå fanns det ett träsliperi kallat Karlshäll mellan åren 1912–1962 som släppte ut orenat processvatten innehållandes kvicksilver tillsammans med rester av träfiber till den närliggande viken, Notviken, som är ett inlopp från Lule älv. Industriella utsläpp av kemikalier och träfiber har resulterat i bildandet av en viss typ av bottensediment, kallad fiberbank. Fiberbankarna innehåller höga nivåer av organiskt material i kombination med lite syre vilket bidrar till stora gasutsläpp från fiberbankarna, gasavgång. Det finns ingen vedertagen metod för att undersöka hur kvicksilverföroreningarna sprids genom gasavgång. Syftet med denna uppsats är att undersöka och hitta metoder som kan undersöka kvicksilverföroreningarnas spridning via gasavgång. Genom en litteraturstudie och intervju med en entreprenör inom miljöteknik framträdde flertalet olika metoder för att kunna kvantifiera eller mäta kvicksilver i gas från fiberbankar. Några av dem var användbara för att mäta volymer av gas. Andra metoder lämpade sig bättre för att samla in gas för analys av koncentrationer av olika ämnen.  Även om alla metoder i viss mån lämpar sig för att undersöka gasavgång från sediment ansågs Jonny Skarps metod som inkluderade både aktiv och passiv provtagning med gasfällor och teflonpåsar vara den mest passande för fiberbankar likt den i Karlshäll. Den passiva metoden innefattar installation av tält över en känd area på sedimentbotten och sen beräkna mängden gas som bubblar upp under en viss tid. Den aktiva insamlingsmetoden bygger på att sediment störs med ett spetsigt föremål, exempelvis ett lod, så att gasbubblor släpper från sedimentet och samlas in med hjälp av en teflon- påse. Teflon-påsen skickas sedan till ett kemiskt laboratorium i Göteborg för analys av innehållet i gasen. Båda dessa provtagningssätt kunde tillsammans mäta mängden kvicksilver ifrån gasen samt volymen av gasen. Denna metod är den enda av de som undersökts i denna uppsats som testats i Sverige på platser med kvicksilver som avgått i gasform från fiberbankar. Dock så är Varadharajan med fleras (2011) automatiserade gas-insamlare ett bra alternativ ifall en hög frekvens av provtagning är nödvändig i kombination med en lång insamlingstid. Denna skulle kunna kombineras med en insamlingsmetod av gasbubblor där det lokala kemilaboratoriet kan analysera innehållet. I detta fall krävs att ett kolfiber-rör är en del av mätinstrumentet. Dock finns det ännu inte något sådant instrument och fler studier behövs för att utveckla ett sådant.

I takt med att medeltemperaturen på jorden ökar och allt fler krav ställs på företag gällande hållbarhetsarbete behöver konsumtionen minska. Bygg- och anläggningssektorn står för 20 procent av Sveriges växthusutsläpp och genererar 14,2 miljoner ton avfall varje år, där större delen av avfallet är dåligt sorterat och ibland funktionsdugligt. Ökandet av återbruk och återvinning skulle medföra både miljömässiga och ekonomiska nyttoeffekter. Detta examensarbete genomfördes tillsammans med Einar Mattsson Byggnads AB där syftet var att undersöka avfallshanteringen, problematiken som finns och hur den går att förbättra för att minska mängden träavfall att gå till energiåtervinning. Studien har innefattat intervjuer med logistikansvariga, träleverantörer, hantverkare och arbetsledare för att bilda en uppfattning om nuvarande avfallshantering och möjligheten till återbruk eller alternativa lösningar. Detta har kompletterats med en enkät och observationer från ett nyproduktionsprojekt där träavfallet har identifierats och volymuppskattats. Kombinationen av använda metoder fastställde engångspall som största fraktion i träavfallet och att mycket avfall bestod av spill från träfiberskivor och konstruktionsvirke. Det framgår att det finns en positiv inställning till återbruk och att ökad plats och kommunikation i stort hade minskat avfallsmängden. Träavfall som inte går att undvika kan i stället gå till produktion av träfiberskivor. En branschgemensam förändring hade kunnat bidra till en omställning men att det för ett enskilt företag kan vara svårt. För att minska mängden lastpall i avfallet ses införande av retursystem som en lönsam och hållbar åtgärd. / Due to the increasing average temperature of the earth and the increase in requirements the consumption must decrease. The construction industry in Sweden currently accounts for 20 per cent of the green house emission and generates 14,2 million tons of waste each year. An increased reuse and recycling would bring both environmental and economic benefits. The thesis is produced in collaboration with Einar Mattsson AB with the purpose to investigate the possibilities to decrease the amount of wood waste in new construction building and to present a recommendation of solutions. To do that, the study has included interviews with logistic managers, wood suppliers, craftsmen, and supervisors which made it possible to estimate current waste management and the possibility of reuse or alternative solutions. The interviews were supplemented with questionnaires and observations form a new construction project, where the volume of wood waste was identified and estimated. This resulted in the largest fraction being disposable pallets and waste of material. Furthermore, the suggested solutions to decrease the waste of wood are believed to be increased communication between all actors involved and greater space of storage may lead to an improved waste management. Also, a change in working methods and agreements with suppliers is required. Wood waste that still occurs should be used in manufacturing of wooden fiberboards used in building production.

Thesis (M. Tech. (Agriculture)) -- Central University of Technology, Free state, 2014 / The main objective of the study was to determine the effect of different potassium concentrations and water quality (salt) compared with the current scientifically accepted potassium threshold level and standardised water quality on the yield, oil composition and leaf morphology of rose geranium (Pelargonium graveolens L.) when grown in different potting-bag sizes and root media under temperature controlled condition. To achieve this objective, two trials were conducted. The first experiment evaluated potassium concentrations at 1.3, 3.3, 5.3 and 7.3 mmol L-1 and potting-bag size of 5 and 10 L. Treatments were arranged in a randomised complete block design assigned in a split plot layout. The main plots consisted of potassium concentration and the pottingbag sizes were allocated to sub-plots. Plant height, potassium content, linalool, geraniol, geranyl formate and the citronellol to geraniol ratio (C:G) were affected by potassium. Plant height, number of branches, the branch to height ratio (B:H), foliar fresh mass (FFM) and oil yield were significantly increased when 5 L potting bags were used. Plant foliar mass was significantly increased by the interaction between 5.3 mmol K L-1 and 5 L potting bags. In the second experiment salt levels applied at 1.6, 2.4, 3.2 and 4.0 mS cm-1 and root media (sand and sawdust) were evaluated. A split plot experimental layout was also used in this trial, with the salt levels allocated to the main plots. The sub-plots were allocated to the root medium. High salt level of 4.0 mS cm-1 reduced the number of leaves, plant height, number of branches, B:H ratio, leaf area, chlorophyll content and foliar fresh mass significantly. The number of leaves, leaf area and FFM were significantly increased where sawdust was used. Time of the day significantly affected stomatal conductance, and the opening of most stomata occurred at 10:00. Geranyl formate and the C:G ratio were significantly affected by salt at 4.0 mS cm-1. Salt induced the development of capitates trichomes. The abaxial leaf surface had a higher number of trichomes than the adaxial leaf surface. A strong polynomial (r2=0.97) relationship was found between capitates trichomes and salt levels. High densities of capitates trichomes were found at high salt level of 4.0 mS cm-1. Although the development of asciiform trichomes was induced, it was at an insignificant level. Trichome densities are therefore not affected by salt. It was therefore concluded that the application of 5.3 mmol K L-1 concentration and the use of 5 L potting bags improves the yield and oil quality of rose geranium. It was evident from this study that rose geranium might Salt induced have some degree of tolerance to salt. It was therefore concluded that rose geranium is a moderately salt-sensitive crop.

The tomato is one of the most important vegetable crops grown in the South African community. Most hydroponic tomato growers in South Africa are using sawdust as a growing medium due to its availability and affordability. However, there is little or no information on how particle sizes of sawdust influence tomato yield and quality. The aim of the study was to determine the effect of the particle size of sawdust on plant growth, yield and quality of tomato. Six treatments of different particle sizes of sawdust i.e. fine (F), medium (M), coarse (C) and 50:50 ratio of F: M, C: M, and C: F extracted from pine tree were used for the experiment. Treatments were arranged in a randomized complete block design with four replicates. The size of the sawdust particles did not have a significant effect on plant height, stem diameter, leaf length and width, shelf-life, marketable yield, total yield and unmarketable yield. A tendency to increase marketable and total yield was observed when tomato plants were grown at a 50:50 C: F ratio. Fruit and leaf mineral content were not affected by sawdust particle size. After completion of the experiment, air- filled porosity was significantly high on particle size C, M, and C: M while the water holding capacity was significantly high on F followed by M. The study showed that the suitable growth medium for production of tomatoes under the hydroponics system used was the CF particle substrate. Generally, the experimental crop performed better under the CF particle substrate in terms of growth parameters, and fruit quality, thus leading to the conclusion that the CF growth medium is ideal for hydroponically grown tomato under a non-environmentally controlled polytunne / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

The tomato is one of the most important vegetable crops grown in the South African community. Most hydroponic tomato growers in South Africa are using sawdust as a growing medium due to its availability and affordability. However, there is little or no information on how particle sizes of sawdust influence tomato yield and quality. The aim of the study was to determine the effect of the particle size of sawdust on plant growth, yield and quality of tomato. Six treatments of different particle sizes of sawdust i.e. fine (F), medium (M), coarse (C) and 50:50 ratio of F: M, C: M, and C: F extracted from pine tree were used for the experiment. Treatments were arranged in a randomized complete block design with four replicates. The size of the sawdust particles did not have a significant effect on plant height, stem diameter, leaf length and width, shelf-life, marketable yield, total yield and unmarketable yield. A tendency to increase marketable and total yield was observed when tomato plants were grown at a 50:50 C: F ratio. Fruit and leaf mineral content were not affected by sawdust particle size. After completion of the experiment, air- filled porosity was significantly high on particle size C, M, and C: M while the water holding capacity was significantly high on F followed by M. The study showed that the suitable growth medium for production of tomatoes under the hydroponics system used was the CF particle substrate. Generally, the experimental crop performed better under the CF particle substrate in terms of growth parameters, and fruit quality, thus leading to the conclusion that the CF growth medium is ideal for hydroponically grown tomato under a non-environmentally controlled polytunne / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

A high priority in order to combat climate change is disposal of waste. In low-income countries, a large portion of biomass residues generated in the forestry, agricultural and industrial sectors could be usable, instead of being seen as waste. For instance, it could be converted into biochar, which is proven to have many environmental benefits. In Rwanda, the agricultural sector employs 80% of the population and accounts for 35% of GDP. This sector, together with later refinement of crops and forestry production, cause large amounts of residue that many times is considered as waste. In this report, a literature study was conducted to evaluate possible biochar production from agricultural and wood wastes in Rwanda. Characteristics that determine if a biomass could be suitable for a biochar production were identified as C, H, O, N, S, hemicellulose, cellulose, lignin, ash and moisture content, residue-to-product ratio, and low heating value. These characteristics were assessed for the chosen Rwandan agricultural and wood wastes, by compiling values from published reports. The result shows that there are large volumes of residues that have potential for biochar production instead of being seen as waste in Rwanda. Biochar production from these wastes could enable environmental benefits for Rwanda, although further investigation of each single biomass could be needed in order to see if it is practically, technically and financially possible to do in reality. / För att bekämpa klimatförändringen är avfallshantering en hög prioritet. I låginkomstländer kan en stor andel av biomassarester som genereras i skogsbruk, jordbruks- och industrisektorer vara användbara, istället för att ses som avfall. Till exempel skulle det kunna omvandlas till biokol, som har visats sig ha många miljömässiga fördelar. I Rwanda arbetar 80% av befolkningen inom jordbrukssektorn och den står för 35% av BNP. Denna sektor, tillsammans med förädling av grödor och skogsbruksproduktion, orsakar stora mängder rester som många gånger betraktas som avfall. I denna rapport genomfördes en litteraturstudie för att utvärdera möjlig produktion av biokol från jordbruks- och träavfall i Rwanda. Egenskaper som avgör om en biomassa kan vara lämplig för en biokolsproduktion identifierades som C-, H-, O-, N-, S-, hemicellulosa-, cellulosa-, lignin-, ask- och fukthalt, samt andel avfall som uppstår i förhållande till färdig produkt och värmevärde. Dessa egenskaper utvärderades för det valda jordbruks- och träavfallet genom att sammanställa värden från publicerade rapporter. Resultatet visar att det finns stora volymer rester som har potential för biokolsproduktion istället för att ses som avfall i Rwanda. En biokolsproduktion från dessa avfall skulle kunna ge miljömässiga fördelar för Rwanda, även om ytterligare undersökning av varje enskild biomassa skulle behövas för att se om det är praktiskt, tekniskt och ekonomiskt möjligt att genomföra i verkligheten.