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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Greenhouse Gas Production and Nutrient Reductions in Denitrifying Bioreactors

Bock, Emily 11 June 2014 (has links)
The global nitrogen cycle has been disrupted by large anthropogenic inputs of reactive nitrogen to the environment. Excess nitrogen underlies environmental problems such as eutrophication, and can negatively affect human health. Managing the natural microbial process of denitrification is advocated as a promising avenue to reduce excess nitrogen, and denitrifying bioreactors (DNBRs) are an emerging technology harnessing this biochemical process. Previous DNBR research has established successful nitrate removal, whereas this study examines the potential to expand DNBR functionality to address excess phosphorus and mitigate the production of nitrous oxide, a potent greenhouse gas. Results from a laboratory experiment supported the hypothesis that the addition of biochar, a charcoal-like soil amendment and novel organic carbon source in DNBR research, would increase nitrate and phosphorus removal as well as decrease the accumulation of nitrous oxide, an intermediate product of microbial denitrification. In order more closely examine the ratio of the products nitrous oxide and inert dinitrogen, development of a novel analytical method to quantify dissolved gases in environmental water samples using gas chromatography mass spectrometry was undertaken. Although static headspace analysis is a common technique for quantifying dissolved volatiles, the variation in sample preparation has recently been revealed to affect the determination of dissolved concentrations of permanent gases and convolute comparison between studies. This work demonstrates the viability of internal calibration with gaseous standard addition to make dissolved gas analysis more robust to variable sample processing and to correct for matrix effects on gas partitioning that may occur in environmental samples. / Master of Science
192

Tillförsel av biokol i skogsmark : Möjligheter och effekter vid användning av biokol i boreal skogsmark på Skogssällskapets fastigheter / Supply of biochar in forests : Possibilities and effects when using biochar inboreal forests at Skogssällskapets properties

Norberg, Andreas January 2024 (has links)
Denna studie undersökte vilka tänkbara effekter applicering av biokol i boreal skogsmark kan ge och vart den största nyttan kan finnas. Studien uppfördes som litteraturstudie och sammanställde relevant forskningsresultat som behandlar biokol i boreal skogsmark. Resultatet visar ökningar i tillväxt hos tall på magrare marker med grövre textur. En ökning av pH-värde noterades vilket generellt ökar markens katjonbyteskapacitet och höjer tillgången på tillgänglig näring. Försurning av skogsmark kan minskas genom biokolets pH-höjande egenskaper. Markens vattenegenskaper påverkades genom en ökning av markfuktighet och kan minska riskerna för skador orsakade av abiotiska och biotiska skadegörare. Utflödet av koldioxid från marken ökade marginellt i förhållande till mängden tillfört kol genom biokolets kolhalt samt markens bundna kollager. Genom framtida kolkreditsystem med applicering av biokol i skogsmark öppnar det upp möjligheter till andra ekonomiska inkomstkällor för skogsägaren än det traditionella virkesvärdet.
193

Динамика эмиссии CO2 и CH4 из почвы с разными биоуглями при выращивании мискантуса сахарного в лабораторных условиях : магистерская диссертация / Dynamics of emissions CO 2 and CH 4 from soil with different biochars when growing Miscanthus sugar under laboratory conditions

Колесников, М. И., Kolesnikov, M. I. January 2024 (has links)
The final qualifying work is presented on 31 pages , contains 2 figures, 1 table, 86 sources. The work is devoted to studying the dynamics of emission CO 2 and CH 4 from soil with different biochars when growing sugar miscanthus in laboratory conditions.” CO 2 and CH 4 emission from the soil when applying biochars of different types in a laboratory experiment, when growing sugar miscanthus ( M iscanthus saccarioflorus L. ). To achieve the research goal, the following tasks must be completed: To measure the dynamics of the flow of CO 2 and CH 4 when biochars with reclamation and sequestration properties are added to the soil with and without growing sugar miscanthus. Identify factors influencing the amount of gaseous carbon losses. In a laboratory experiment, we measured the emission of CO 2 and CH 4 from the soil with the introduction of biochars with reclamation and sexestration properties and without the addition of biochars, with and without the cultivation of sugar miscanthus. Biochars were obtained from birch sawdust, as well as from the biomass of tall grass plants: Amaranthus cruentus L. (Scarlet amaranth), Miscanthus saccarioflorus L. (Miscanthus sugar). Based on literature data, the resulting biochars were classified into two types: with increased reclamation properties (biochars from A. cruentus ) and sequestration properties (biochars from sawdust and M. saccarioflorus ). Biochar was added at a dose of 2% by weight of the air-dry soil. The experiment was carried out in 3-liter pots with a duration of illumination with full-spectrum phytolamps for 16 hours, while maintaining the soil moisture capacity of 60%. The duration of the experiment was 117 days. Soil respiration was measured daily for the first week, then once a week. To determine the flow of CO 2 , CH 4 , H 2 O , a Li-cor 7810 CH 4 / CO 2 / H 2 O Trace Gas Analyzer was used. When conducting two-way ANOVA on the data obtained, the following results were obtained: The rate of carbon dioxide release was influenced by the type of biochar at the beginning of the experiment and the type of biochar and the presence of plants at the end of the experiment. At the beginning of the experiment, in the control variants with plants ( M. saccarioflorus ), the respiration rate was statistically significantly higher than in the experimental variants: samples with biochar from M. saccarioflorus and samples with biochar from sawdust. At the end of the experiment, samples with biochar from A. cruentus with plants ( M. saccarioflorus ) emitted significantly more than the control with plants. As for methane, on average, it was absorbed. The analyzes showed a significant influence of the “variant” factor and its interaction with the “presence of plants” factor at the beginning of the experiment and the absence of significant differences at the end. The most pronounced runoff occurred at the end of the experiment. A significant variation in the CH4 runoff between experimental variants was observed only at the initial stage. / Работа посвящена изучению динамики эмиссии CO2 и СН4 из почвы с разными биоуглями при выращивании мискантуса сахарного в лабораторных условиях». Цель исследования – оценка динамики эмиссии CO2 и СН4 из почвы при внесении биоуглей разных типов в лабораторном эксперименте, при выращивании мискантуса сахарного (Miscanthus saccarioflorus L.). Для достижения цели исследования необходимо выполнить следующие задачи: Измерить динамику потока CO2 и СН4 при внесении в почву биоуглей с мелиоративными и секвестрационными свойствами при выращивании и без выращивания мискантуса сахарного. Выявить факторы, влияющие на величину газообразных потерь углерода. В лабораторном эксперименте проводили измерения эмиссии CO2 и СН4 из почвы с внесением биоуглей с мелиоративными и сексестрационными свойствами и без внесения биоуглей, с выращиванием и без выращивания мискантуса сахараного. Биоугли получали из березового опила, а также из биомассы высокотравных растений: Amaranthus cruentus L. (Амарант багряный), Miscanthus saccarioflorus L. (Мискантус сахарный). На основании литературных данных полученные биоугли были отнесены к двум типам: с повышенными мелиоративными свойствами (биоугли из A. cruentus) и секвестрационными свойствами (биоугли из опила и M. saccarioflorus). Биоуголь вносили в дозе 2 % от массы воздушно-сухой почвы эксперимент проводили в 3-х литровых горшках с продолжительностью освещения фитолампами полного спектра 16 часов, при поддержании влагоемкости почвы 60 %. Длительность эксперимента – 117 дней. Почвенное дыхание измеряли первую неделю ежедневно, далее один раз в неделю. Для определения потока CO2, СН4, H2O использовали газоанализатор Li-cor 7810 СН4/ CO2/ H2O Trace Gas Analyzer. При проведении двухфакторных дисперсионных анализов относительно полученных данных, были получены следующие результаты: На скорость выделения углекислого газа влиял тип биоуглей в начале эксперимента и тип биоуглей и наличие растений – в конце эксперимента. В начале эксперимента в контрольных вариантах с растениями (M. saccarioflorus) скорость дыхания была статистически значимо больше, чем в опытных вариантах: образцы с биоуглем из M. saccarioflorus и образцы с биоуглем из опила. В конце эксперимента образцы с биоуглем из A. cruentus с растениями (M. saccarioflorus) эмитировало значимо больше, чем контроль с растениями. Что касается метана, в среднем, происходило его поглощение. Проведенные анализы показали значимое влияние фактора «вариант» и его взаимодействия с фактором «наличие растений» в начале эксперимента и отсутствие значимых различий в конце. Наиболее выраженный сток происходил в конце эксперимента. Существенное варьирование стока СН4 между вариантами эксперимента наблюдали только на начальном этапе.
194

Phosphorus and Nitrogen Removalin Modified Biochar Filters / Fosfor och kväverening i modifierade biokolsfilter

Stenström, Ylva January 2017 (has links)
Onsite wastewater treatment systems in Sweden are getting old and many of them lack sufficient phosphorus, nitrogen and organic carbon reduction. Biochar is a material that has been suggested as an alternative to the common sand or soil used in onsite wastewater treatment systems. The objective of this study was to compare the phosphorus removal capacity between three different modified biochars and one untreated biochar in a batch adsorption and column filter experiment. The modifications included impregnation of ferric chloride (FeCl3), calcium oxide (CaO) and untreated biochar mixed with the commercial phosphorus removal product Polonite. To further study nitrogen removal a filter with one vertical unsaturated section followed by one saturated horizontal flow section was installed. The batch adsorption experiment showed that CaO impregnated biochar had the highest phosphorus adsorption, i.e. of 0.30 ± 0.03 mg/g in a 3.3 mg/L phosphorus solution. However, the maximum adsorption capacity was calculated to be higher for the FeCl3 impregnated biochar (3.21 ± 0.01 mg/g) than the other biochar types. The pseudo 2nd order kinetic model proved better fit than the pseudo 1st order model for all biochars which suggest that chemical adsorption was important. Phosphorus adsorption to the untreated and FeCl3 impregnated biochar fitted the Langmuir adsorption isotherm model best. This indicates that the adsorption can be modeled as a homogenous monolayer process. The CaO impregnated and Polonite mixed biochars fitted the Freundlich adsorption model best which is an indicative of heterogenic adsorption. CaO and FeCl3 impregnated biochars had the highest total phosphorus (Tot-P) reduction of 90 ± 8 % and 92 ± 4 % respectively. The Polonite mixed biochar had a Tot-P reduction of 65 ± 14 % and the untreated biochar had a reduction of 43 ± 24 %. However, the effluent of the CaO impregnated biochar filter acquired a red-brown tint and a precipitation that might be an indication of incomplete impregnation of the biochar. The FeCl3 effluent had a very low pH. This can be a problem if the material is to be used in full-scale treatment system together with biological treatment for nitrogen that require a higher pH. The nitrogen removal filter showed a total nitrogen removal of 62 ± 16 % which is high compared to conventional onsite wastewater treatment systems. Batch adsorption and filter experiment confirms impregnated biochar as a promising replacement or addition to onsite wastewater treatment systems for phosphorus removal. However the removal of organic carbon (as chemical oxygen demand COD) in the filters was lower than expected and further investigation of organic carbon removal needs to be studied to see if these four biochars are suitable in real onsite wastewater treatment systems. / Många av Sveriges små avloppssystem är gamla och saknar tillräcklig rening av fosfor, kväve och organiskt material. Följden är förorenat grundvatten samt övergödning i hav, sjöar och vattendrag. Lösningar för att förbättra fosfor- och kvävereningen finns på marknaden men många har visat brister i rening och robusthet. Biokol är ett material som har föreslagits som ersättare till jord eller sand i mark och infiltrationsbäddar. Denna studie syftade till att i skak- och kolonnfilterexperiment jämföra fosforreduktion mellan tre modifierade biokol och ett obehandlat biokol. Modifieringen av biokolet innebar impregnering med järnklorid (FeCl3), kalciumoxid (CaO) samt blandning med Polonite som är en kommersiell produkt för fosforrening. För att undersöka förbättring av kväverening installerades även ett filter med obehandlat biokol där en vertikal aerob modul kombinerades med en efterföljande horisontell anaerob modul. Skakstudien där biokolen skakades i 3.3 mg/L fosforlösning visade att adsorptionen var högst i det CaO-impregnerade biokolet, 0.3 ± 0.03 mg/g. Den maximala potentiella fosforadsorptionen beräknades dock vara högst för biokolet som impregnerats med FeCl3, 3.21 ± 0.01 mg/g. Skakförsöket visade också att fosforadsorptionen var främst kemisk då adsorptionen passade bättre med pseudo andra ordningens modell än pseudo första. Adsorption av fosfor på obehandlat biokol och FeCl3 impregnerat biokol modellerades bäst med Langmuir modellen, vilket tyder på en homogen adsorption. Det Polonite-blandade biokolet och CaO-impregnerade biokolet modellerades bäst med Freundlich modellen vilket är en indikation på en heterogen adsorptionsprocess. Biokol impregnerat med CaO och FeCl3 gav de högsta totalfosforreduktionerna på 90 ± 8 % respektive 92 ± 4 %. Biokolet som var blandat med Polonite hade en reduktion på 65 ± 14 % och det obehandlade biokolet 43 ± 24 %. Ett problem med filtratet från CaO-filtret var att det fick en rödbrun färg samt en fällning vilket kan ha berott på ofullständig pyrolysering och impregnering. Filtratet från det FeCl3 impregnerade biokolet hade mycket lågt pH vilket kan vara problematiskt om mikrobiologisk tillväxt i filtret för rening av kväve och organiskt material vill uppnås. Filtret för kväverening gav en total kvävereduktion på 62 ± 16 % vilket är högre än kommersiella system. Resultaten från skak och filterstudien visade på att impregnerade biokol kan ge en förbättrad fosforrening om de skulle användas i små avloppssystem. Rening av organiskt material, kemisk syreförbrukning (COD), var dock låg i alla filter och behöver studeras ytterligare för att avgöra om dessa biokol är lämpliga för småskalig avloppsvattenrening.
195

The Effect on Mechanical Properties in Biochar Replaced Cement & Aggregate in Concrete Before and After Fire Exposure

Hansen, Felix, Berglund, Mathias January 2023 (has links)
Concrete is good as a construction material regarding fire and its properties regarding strength. However, the concrete expands and cracks due to fire resulting in structural damage. According to the literature the concrete usually loses its strength during and after fire exposure due to themechanical and physical changes.Concrete consists of cement, water, aggregates of different sizes, and usually some sort of plasticiser depending on its final use. Globally the concrete production releases about 4.5 billionmetric tons of carbon dioxide, which is about 8% of all the emissions of carbon dioxide in the world (Naturskyddsföreningen, 2022).The main components in cement are limestone and marlstone which are melted and turned to clinker. The clinker is mixed with sand and gypsum to make cement. Due to the high releases of carbon dioxide from the production of cement and the destruction of the environment mining of the raw materials, Sweden had a concrete-crisis in the summer of 2021, this was due to the government denied the main cement company Cementa AB to continue to mine limestone on the island of Gotland. Due to this decision new sustainable components to replace the components to produce concrete is critical. An alternative material called biochar may be suitable as a component in concrete. Biochar is a renewable product from pyrolysis of biomass. The favorable properties of biochar such as low density, high specific area and low thermal conductivity has the potential to lower the carbon footprint of concrete. This thesis evaluates the properties and performance for different biochar ratios mixed within concrete before and after exposure to fire in a furnace that followed the standard ISO 834 curve up to 650 ℃. In particular, experiments were conducted to observe how the mechanical properties (e.g., tensile and compressive strengths) are affected by exposure to fire that caused a temperature rise of up to 650 ℃. By analyzing the results from the experiments, it is seen that the workability of the concrete decreases with higher ratios of biochar due to the biochar’s water absorption properties. The compressive and tensile strength tests before fire exposure, for both aggregate and cement replaced samples, resulted in the average strength decreasing with higher ratios of biochar. Interestingly, iiithe results after fire exposure represented higher compressive strengths for both cement and aggregate replaced samples for all ratios of biochar. However, the tensile strength after fire exposure generally decreased with higher ratios of biochar. Differential scanning calorimetry and infrared spectroscopy were performed to gain an insight into the reason for the increase in compressive strength after fire exposure. Most probably, when the silica, present in the cement, was exposed to 650 °C under fire, it softened and fused the other components, which led to stronger compressive strengths.
196

Agricultural waste and wood waste for pyrolysis and biochar : An assessment for Rwanda​ / Jordbruks- och träavfall för produktion av biokol : En utvärdering för Rwanda​

Eliasson, Jenny, Carlsson, Viktor January 2020 (has links)
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.
197

Möjligheterna för upprättning av en biokolsanläggning inom Uppsala kommun / The possibilities for establishing a biochar facility within Uppsala Municipality

Lundqvist, Hugo, Hammar Lundberg, Emil January 2024 (has links)
Klimatförändringar till följd av den ökande halten koldioxid i atmosfären är en växande utmaning. Som följd av detta har Uppsala kommun ökat sina hållbarhetsinsatser, varav biokol har visat sig vara ett lovande alternativ. Biokol fungerar som en kolsänka genom att lagra kol långsiktigt i marken, samtidigt som det förbättrar jordens struktur och näringsinnehåll. Denna rapport syftar till att utforska möjligheterna till att upprätta en biokolsanläggning inom Uppsala kommun. För att utreda möjligheterna till en sådan anläggning utförs analys av tillgängligt biomassaflöde, utvärdering av pyrolysteknik samt identifiering av platsspecifika begränsningar. Därtill har tillstånd och krav på en anläggning identifierats och sammanställts.  Metoden bygger på ett teoretiskt ramverk, som appliceras för att utvärdera och sedan maximera lönsamheten vid rekommendation av plats. Intervjuer har genomförts, för att skapa en förståelse för teknik och drift samt för att fastställa diverse kostnadsposter. En budgetkalkyl har sedan skapats utifrån kartlagda kostnader, för vilken en finansiell analys sedan utförts. Med utgångspunkt i den analysen har lämpliga platser valts ut, vilka kompletterats med en rekommendation av optimal teknik och resurshantering. Miljörelaterade externaliteter för rekommenderade platser har tilldelats ett monetärt värde, för att sedan sammanvägas med det finansiella resultatet i en kostnads- och nyttoanalys Utifrån avgränsningen att det finns en stabil marknad och efterfrågan på biokol, har analysen resulterat i en hög avkastning på de rekommenderade investeringarna, samt en märkbar förbättring då externaliteterna inkluderas. Resulterande slutsatser har varit klimatnyttor skulle utgöra en stor del av lönsamheten för Uppsala kommun, men att avgränsningen riskerar att ge missvisande finansiella resultat. Framtida arbeten bör med fördel kartlägga marknaden för biokolsproduktion, samt analysera och utvärdera pris och efterfrågan för avsättningar. / Climate change due to the increasing levels of carbon dioxide in the atmosphere, is a growing challenge. As a result, Uppsala Municipality has increased its sustainability efforts, among which biochar has proven to be a promising alternative. Biochar acts as a carbon sink by storing carbon long-term in the soil, while also improving soil structure and nutrient content. This report aims to explore the possibilities for establishing a biochar facility within Uppsala Municipality. To investigate the feasibility of such a facility, an analysis of available biomass flow, evaluation of pyrolysis technology, and identification of site-specific constraints are conducted. Additionally, the permits and requirements for a facility have been identified and compiled. The methodology is based on a theoretical framework, applied to evaluate and then maximize profitability when recommending a site. Interviews have been conducted to understand technology and operations, and to determine various cost items. A budget calculation has been created based on identified costs, for which a financial analysis has then been performed. Based on this analysis, suitable sites have been selected, complemented with a recommendation of optimal technology and resource management. Environmental externalities for recommended sites have been assigned a monetary value, which is then combined with the financial result in a cost-benefit analysis. Assuming a stable market and demand for biochar, the analysis has resulted in a high return on the recommended investments, along with a noticeable improvement when externalities are included. The resulting conclusions indicate that climate benefits would constitute a significant part of the profitability for Uppsala Municipality, but that the assumption risks providing misleading financial results. Future work would benefit from mapping out the market for biochar production, as well as analyzing and evaluating the price and demand for biochar outputs.
198

Fortification of soil-based wastewater treatment systems with versatile ubiquitous reactive media for enhanced removal of phosphorus and other pollutants

Kholoma, Ezekiel January 2017 (has links)
Concerns about potential risks posed by discharge from small-scale wastewater treatment (SWT) systems to receiving water bodies have prompted robust enforcement of national discharge quality standards in rural areas of most developed countries. Consequently, communities in such places are in need of effective technologies with which to achieve compliance. Currently, reactive filter (RF) media are increasingly preferred over advanced alternatives, due mainly to their simplicity, affordability and proven potential. However, many of the field-tested filters are commercial products which are costly and scarce but also only capable of removing few contaminants they are engineered to target hence often requiring to be coupled with other treatment units to achieve full treatment. In the preliminary findings of this study, biochar (BC) was identified and thus suggested basing on existing literature, as a versatile ubiquitous low-cost material for treating wastewater. Its effectiveness in fortifying sand (Sa) and gas concrete (GC)-based SWT facilities was later demonstrated in long-term experiments using laboratory packed bed reactors and field constructed filter beds. The efficacy of SaBC and GCBC systems in reducing turbidity (&gt;95%), DOC (60%; p&lt;0.05) and PO43- (40-90%; p&lt;0.05) was significantly higher than for their reference counterparts. Further, sorbed P was more leachable from Sa (11.2 mgkg-1) and SaBC (20.5 mgkg-1) filters but more extractable and hence plant-available in GC (65-91 mgkg-1). Therefore, the study concluded that fortification of soil-based systems with biochar filters may be a promising solution in enhancing performances of soil-based wastewater treatment systems, while P-rich RF media can act as a nutrient source for plants if recycled to agriculture. / <p>NB: Research Funder was: Botswana International University of Science and Technology, Botswana. QC 20170524</p>
199

Impact of biochar manipulations on water and nitrogen

Ulyett, James January 2014 (has links)
A loss of soil organic matter (SOM), whether through natural means or management practices, results in soil degradation. Biochar as a soil amendment can alter soil properties, ultimately affecting the availability of nitrogen and water to plants and thus crop growth. The effects of biochar are not definitive, and often dependent on both the soil type and the biochar applied. Biochar properties can change according to the feedstock and production parameters, thus for their effective use further investigation is required to link biochar properties to its effects in soil. A high-temperature (600˚ C) biochar from a mixed-hardwood feedstock was investigated. The biochar increased the soil water retention, as demonstrated by a water release curve and field trials. This retention was predominant at higher water potentials, which was attributed to the greater number of meso (storage) pores in the biochar. Biochar did not affect the soil’s saturated hydraulic conductivity; this is thought to be due to the low number of macro (transmission) pores in the biochar. Thus there was no effect on the transmission rate in the soil. Biochar reduced gross ammonium levels in the soil via adsorption, but resulted in increased non-exchangeable ammonium levels, possibly due to physical entrapment. Where carbon was already abundant in the organically managed soil, the adsorbed ammonium reduced nitrification through lower substrate availability. The range of carbon fractions added as a result of the biochar amendment increased the total organic carbon (TOC) content of the soil, but this supplementary carbon was released by the microorganisms as carbon dioxide. Microorganisms in the relatively carbon poor conventionally managed soil (with lower TOC), assimilated the additional labile carbon increasing microbial biomass. The higher microbial biomass, combined with improvements in pH and the higher ammonium levels (as a result of the ammoniacal fertiliser) increased nitrification. These changes in water and nitrogen availability did not alter crop yields as measured in the glasshouse and field trials. The effects of this biochar in a sandy agricultural soil depended on the type and level of carbon and nitrogen present in the soil, thus consideration of these factors should be taken when applying.
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A study of the performance of biochar as adsorbing agent in o‐DGT devices / En studie av egenskaperna hos biokol som adsorberande agent i o‐DGT anordningar

Eliasson, Anna January 2017 (has links)
A new complex aspect in the matter of water quality is the occurrence of emerging organic pollutants and contaminants in waste water. The currently low extent to which treatment of waste water is performed in Brazil, and in the world as a whole, there is a considerable need for development of cheap and accurate in-situ sampling methods for far-reaching studies of surface water quality. The lack of such methods today makes the maintenance and establishing of sanitary safety difficult. This diploma work gives a brief introduction to the basic principles of the passive sampling method known as Diffusive Gradient in Thin-films (DGT). A method that could be useful for such monitoring of quality in water bodies world wide. The aim of this study is to develop a method, for the detection of organic emerging pollutants and contaminants – i.e. compounds, which usually are present at very low concentrations when found in the environment as a result of human activity. More specifically, this work investigates the potential and usefulness of the application of DGT devices in detection of organic compounds that can affect human health and ecosystems, even at low concentrations, however, their effects still are in need of further investigations. This study focuses on both purely technical as well as practical points of views. The efficiency of organic DGT (o-DGT) with biochar as the adsorbing agent is examined targeting the detection of organic pollutants and contaminants in surface water. In this sense, the specific aim of the work is to evaluate the performance of biochar as adsorbing agent. This work showed that the performance of biochar as the adsorbing agent in binding layers in o-DGT sample devices can be considered as satisfactory since all compounds of interest in this study was successfully detected, quantified an identified. Further investigations in the future are needed to determine the effects of varying pH, temperature and ion concentration in the deployment media, as well as the properties of the binding layer in relation to concentration of biochar and the thickness of the layer. These in order to optimize the method for in-situ water sampling, aiming conventional use of biochar as the adsorbing agent in the future.

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