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I rådande klimatförändringar ses ett stort behov av långsiktiga och stabila lösningar för att både minska och för att binda kol. En kolsänkeprodukt är biokol som utöver sin förmåga att agera kolsänka även bidrar som jordförbättrare när den tillsätts i planteringar och till skogar. Biokol har även setts ha en tillväxthöjdande effekt på träd och växtlighet. I studien ses att biokol kan anses vara en kolsänka. Studiens resultat indikerar även att biokol har en effekt på trädens diametertillväxtoch jordens organiska halt. Studien indikerar på att en påverkan av biokol finns i Varvsparken i Malmö. Som en framtida klimatnyttig produkt ses biokol ha stor potential men där tillsättning av biokol behöver anpassas efter jordtyp, önskade effekter och långsiktig påverkan.

Compaction of urban soil where stormwater infrastructures are built reduces infiltration, vegetation growth, and stormwater treatment capacity. Biochar—a carbonaceous porous material produced by pyrolysis of organic waste – can be used as a soil amendment to improve the function of stormwater infrastructure in addition to the proven benefit of increased pollutant removal. However, the benefits depend on the biochar’s properties such as particle size distribution and concentration. Further, because biochar’s particle size distribution is altered by compaction, the hydraulic functions of compacted biochar amended soil is unknown. Herein, we examined the effect of biochar concentrations (0-6% w/w) and particle sizes (unsieved, sieved to < 2mm, and to < 0.5 mm) on water retention and saturated or unsaturated hydraulic conductivity of compacted stormwater media amended with biochar. Our results show the particle size of biochar plays a critical role in whether or not compaction is alleviated: while increasing concentration of unsieved biochar increased hydraulic conductivity up to 3% biochar, increasing concentration of fine biochar (< 2 mm) resulted in consistent decline in hydraulic conductivity under compaction. The results indicate that large biochar particles can effectively dissipate the compaction energy, while the fine biochar under compaction increased clogging by generating more fines that occupy the pores. Water retention improved regardless of the size distribution of added biochar, indicating that addition of biochar would reduce the irrigation requirement to maintain plant health in dry climate or water-stressed conditions. Overall, the results indicate that biochar addition can be effective in mitigating the negative impacts of compaction on stormwater infrastructures, depending on the proportion of coarse biochar. / Geology

Capacitive deionization based on electrosorption has become a viable process for brackish water desalination. In this study, activated biochar was employed as low-cost and alternative carbon-based electrodes substituting activated carbon with comparable adsorption capacity. Effects of different activation temperatures of the biochar were studied by physical characterization (i.e. SEM, TEM, elemental analysis, and Raman spectroscopy) and electrochemical characterization (i.e. cyclic voltammetry and galvanostatic charge/discharge measurement) based on the electrical double layer theory. The highest specific capacitance obtained (118.50 F g-1) was from activated biochar electrode treated at 800°C. The removal capacity was investigated by AAS and conductivity measurements. Several limitations associated with them were identified to improve the measurements. The removal capacity of biochar electrode is ~ 2 mg g-1 with significant results for both one-sided and two-sided t-test. In summary, activated biochar can be used as a cheap-alternative electrode material for desalination based on capacitive deionization.

Bioenergy is extracted from biomass. What counts as biomass is generally quite diverse, but broadly speaking, it is material that previously lived. Today, energy extracted from biofuels make up around 23% of Stockholm city's total energy consumption. Stockholm city has set a goal to be a fossil-free city by 2040, i.e. zero emissions from energy use. Two sectors have been identified where emissions occur and these are the transport sector and the electricity and heating sector. This thesis will only address the electricity and heating sector. This includes all energy consumption within Stockholm city municipality. When Stockholm is developing towards a fossil fuel free city, it’s interesting to look at how important bioenergy will be as an energy source in the future. This thesis has scrutinized the role of bioenergy in reaching a fossil fuel free city. Three major policies have been investigated. The carbon dioxide tax and the emission rights system have promoted the bioenergy and its deployment in a positive way. The system of electricity certificates has shown to indirectly affect the bio energy in a negative way. The key finding is that bioenergy will have a great impact in reaching the goal mainly through its contributions with negative emissions, but it is also an important substitute to fossil fuels. / Bioenergi utvinns ur biomassa eller biobränslen. Biomassa och biobränslen är ganska diffusa begrepp då definitionen varierar runt om i världen, men generellt sett är det material som tidigare levt. Idag utgör energi från biobränslen cirka 23% av Stockholms stads totala energiförbrukning. Stockholms stad har satt upp ett mål att vara en fossilfri stad år 2040, det vill säga inga utsläpp från stadens energiförbrukning. Det finns två huvudsakliga sektorer där koldioxidutsläpp förekommer, dessa är transportsektorn och eloch värmesektorn. Detta inkluderar all energiförbrukning inom Stockholms kommuns gränser, till exempel uppvärmning av hushåll och energin de fordon som körs i staden förbrukar. När Stockholm utveckling går mot att bli en fossilbränslefri stad är det intressant att se hur viktig bioenergi kommer att vara som energikälla i framtiden. Denna rapport granskar bioenergins roll i att nå klimatmålet till 2040. De huvudsakliga slutsaterna är att bioenergi kommer ha en stor och viktig roll i att nå målet och att dess största inverkan kommer vara de negativa utsläppen. Vissa lagar har främjat bioenergin medans vissa indirekt har påverkat dess utveckling negativt. Bioenergin har en ljus framtid i Stockholm.

Household air pollution annually kills around 14 300 people in Kenya, due to the hazardous smoke of incomplete combustion coming from inefficient stoves. Exposure to this smokeleads to lethal health issues for the women and children staying in these kitchens, but the smoke also leads to a contribution to global warming. Which makes it important finding are placement for the inefficient traditional cooking methods. This report presents results from a field work situated in Kibugu, Embu in central Kenya. It includes testing of three stoves, the traditional Three stone open fire and two biochar producing stoves, the previously tested stove Gastov made by KIRDI and the MiG|BioCooker made by Make It Green Solutions AB. The data was collected using participatory cooking tests where five households got to cook the traditional meal Ugali with Sukuma wiki and Githeri (maize and beans). Firewood consumption, emissions of CO and PM, user experience and char production were measured during the test, to be able to compare the stoves. The results indicate that the MiG|BioCooker can decrease the emissions of PM2.5 and CO in the kitchens and produce biochar. But on the other hand, cooking with three stone open fire more effective in terms of cooking time. Even though the MiG|BioCooker could improve the conditions of the household’s indoor air, the users seems to prioritize the practical characteristics of the three stone open fire that gives them more time and making it easier to cook. But with some modifications and by further use of the MiG|BioCooker, it might be apossible substitute to the three stone open fire in the future.

The aim of the project was to investigate the possibility of producing and utilizing bioenergy from available local resources in the village Linga Linga, Mozambique. Suitable conversion techniques for producing and utilizing bioenergy were identified through a literature study. The investigated techniques were the concept of gasifier cookstoves, the method of producing charcoal from biomass and anaerobic digesters. Through observations and interviews in the village, available local resources suited for the conversion techniques were identified. In the field study, it was found that there is a surplus of solid biomass which led to the conclusion that a gasifier cookstove is suitable to implement. In order to analyze if a gasifier cookstove is suitable for the households, interviews were carried out in ten households in the village. Aprototype of a gasifier cookstove was built with local resources to determine if the technique can be applied. The prototype was tested and evaluated in order to analyze if it will contributeto a more efficient use of resources. One of the conclusions of the study was that a gasifier cookstove can be valuable for the households in several ways, but that cultural differences can make it hard to implement.

The decrease in subtherapeutic antibiotic administration in poultry has increased the need to address production challenges caused by pathogens, such as E. coli. One potential way to improve bird health and reduce bacterial infection is through the addition of litter amendments that absorb moisture. Biochar (BC) has previously been shown to increase water holding capacity in poultry litter, but its effects on E. coli mitigation are unknown. The objectives of this research were to 1) evaluate water activity of poultry litter amended with pine and miscanthus BC, and 2) determine the effects of different BC inclusion rates on litter E. coli populations. The studies found that BC increased water activity when mixed with broiler litter, and pine BC resulted in lower E. coli counts over time than miscanthus BC. An inclusion rate of 30% by weight of pine BC was most effective at reducing E. coli populations in broiler litter.

Uppsala Kommun is developing a new city district called Sydöstra staden (SÖS) as an innovative and transformative city district. A technical supply system that aligns with the district’s goals is pyrolysis. Pyrolysis is a process where biomass is heated without the supply of oxygen. This leads to carbonization where the energy is converted to biochar and heated gas that can be used for district heating. The biochar, which is considered as a carbon sink, could be the path for the municipality to achieve their climate goals for 2050. The aim of this project is to investigate the viability of providing district heating to SÖS through pyrolysis. Three scenarios based on biomass assets of garden waste, manure, and wooden chips will be evaluated from four perspectives: climate impact, economic feasibility, district heating coverage, and placement considerations. The method is a model constructed in python that simulates how much heat and biochar that can be produced including an income statement and how the price of biochar relates to the return of investment. The biochar price and biomass flow are two parameters that are examined in the sensitivity analysis. The model enables comparisons between the outcomes of the pyrolysis process and the heat energy demands in SÖS, the biochar usage in Uppsala and the municipality’s CO2 emissions. The results show profitable reactor alternatives in all three scenarios even without selling CORCs. However, the profitability is heavily reliant on maximizing the utilization of burned biomass. Furthermore, the first two scenarios had a negligible climate impact while the most profitable reactor in scenario 3 had a large impact on the municipality’s climate goals. Also, the coverage of district heating has been evaluated due to the asset of biomass as well as placement requirements have been stated.

Water pollution represents one of the major concerns of the modern world, after scientific and industrial development that generates hazardous organic and inorganic contaminants. Biochar (BC) has gained tremendous attention in the past decade as a cheap and efficient adsorbent for organic and inorganic contaminants from aqueous solutions. BC is considered to be a low-cost alternative to activated carbon, however, BC typically suffer performance reductions due to their low surface areas and poor mechanical properties. The main objective of this work is to develop novel biochar materials by modifying the biochar surface for the removal of organic and inorganic contaminants from water. In recent years, biochar modifications involving various methods such as, acid/base treatment, impregnation of mineral sorbents, functional groups incorporation, steam activation and magnetic modification have been widely studied. Chapter I summarizes these biochar modification methods. In Chapter II, Chitosan-Modified fast pyrolysis BioChar (CMBC) was used to remove Pb2+ from water. CMBC was made by mixing pine wood biochar with a 2% aqueous acetic acid chitosan (85% deacylated chitin) solution followed by treatment with NaOH. CMBC removed more Pb2+ than non-modified biochar suggesting that modification with chitosan generates amine groups on the biochar surface which enhance Pb2+ adsorption. Chapter III describes the fast nitrate and fluoride adsorption and magnetic separation from water on iron oxide particles dispersed on Douglas Fir biochar. Nitrate and fluoride adsorption occurred by electrostatic attraction over the wide 2 to 10 pH range. In the chapter IV, aniline and nitrobenzene removal from water was studied using magnetized and nonmagnetized Douglas Fir biochar. The adsorption of aniline and nitrobenzene occurred mainly through pi-pi electron interactions over the wide 2 to 12 pH range and H-bonding. The surface morphology, chemistry, and composition of the modified biochars were examined by SEM, SEM-EDX, TEM, PZC, XPS, XRD, FTIR, TGA, DSC, elemental analysis, and surface area measurements.