Intentional amendment of soil with charcoal (called biochar) is a promising new approach to sequester atmospheric carbon dioxide and increase soil fertility. However, the environmental properties of biochars can vary with production conditions, making it challenging to engineer biochars that are simultaneously optimized for carbon sequestration, nutrient storage, and water-holding capacity. For this reason, I have undertaken a systematic study to (a) determine the pyrolysis conditions that lead to biochars with desired chemical and physical properties, and (b) find how these properties affect the water-holding capacity and nutrient adsorption in biochar-soil mixtures. First, a library of biochars was produced in a custom-built pyrolysis reactor under precisely controlled conditions. The chemical and physical structures of the produced biochars were characterized with various analytical techniques including 13C NMR, XPS, EA and BET pore surface analysis. My results suggest that the chemical composition and pore structure of biochars are determined not just by the maximum heat treatment temperature, but also by several other factors that include the pyrolysis heating rate, treatment time at the maximum temperature and particle size. I also tested a new approach that combines thermogravimetric reactivity measurements, diffusion-reaction theory and structural models to achieve a better characterization of the complicated multi-scale pore structure of biochars. The structural models treat biochars as porous solids having micro- and macropores of different shapes and exhibiting widely ranging pore-size distributions. Simulations results are then compared to experimental data to identify the presence of ordered or random pore networks and test their size distributions and connectivity. I then developed a multi-solid one-dimensional model that can use experimentally determined biochar properties to predict their field performance in beds packed with soil/biochar mixtures. The model used a system of coupled partial differential equations to describe the dynamic adsorption/elution of ammonium nitrate, a model fertilizer, in columns packed with biochar/soil mixtures and perfused with aqueous solutions of the fertilizer. The PDE system was solved using orthogonal collocation on finite elements. My chromatographic model accounted for all the important processes occurring in this system, including external mass transfer between the fluid phase and the solid particles, as well as intraparticle diffusion and adsorption of the solute on the pore surface area of the sorbents. To our knowledge, this is the first chromatographic model that accounted explicitly for the presence of two solid phases with widely different pore structures and adsorption capacities. A systematic parametric study was carried out to determine the importance of each system parameter. The adsorption equilibrium parameters and the intraparticle effective diffusivity of ammonium had the most significant effect on environmental performance. To complete the theoretical analysis, I also developed a model to describe the saturation and drainage of water from the packed column. The model accounted for all the important processes occurring in this system: (a) water exchange between the interstitial pore region and two different smaller pore regions and (b) water flow inside the larger pore region and the two different smaller pore regions. The transient mass balances led to a system of partial differential equations that was solved using block centered finite difference.

Environmental sustainability in Sweden is challenged by rising greenhouse gas emissions from transportation, input-intensive agriculture and potentially unsustainable removal of organic material from forests and farmland. The Swedish government is working towards sixteen environmental quality objectives in order to overcome these problems, among others.  The past decade gave rise to an international research community dedicated to investigate the age-old practice of applying charcoal to soil, practiced most notably by ancient civilisations in the Amazon region of South America. The high level of interest and controversy around this subject inspired this investigation of biochar’s potential benefits in Sweden.  A scientific study was conducted to examine the potential of biochar to enhance environmental sustainability in Sweden. This was largely a desk study, supplemented by expert interviews, GIS map work, an experiment and mathematical analysis.  It was found that there was insufficient research to date to prove the agronomic benefits of biochar in Sweden. More field studies are required to build up the evidence of its potential. Furthermore, as the rate of mineralization of the carbon content is dependent on numerous factors, including the composition of the soil to which the biochar is applied, it is difficult to conclusively define biochar’s carbon storage potential.  This study adds to the existing body of knowledge on the subject by integrating the conclusions from a variety of studies and expert opinions, as well as by providing maps indicating land areas in Sweden that would be likely to benefit from biochar application.

Reclamation success is highly dependent upon final soil quality of stockpiled soils, such as those found Cold Lake Oil Sands Region. Stockpiled soils, however, are generally poor in quality. Soils were amended with, biochar (BC), humalite (HU), a sub-bituminous coal; and peat (PT), as well as 50:50 blends of biochar:humalite (BCH) and biochar:peat (BCP). These amendments were applied at rates of 0, 6.55, 13.1 and 26.2 g C kg-1 each. Biochar, PT, and BCP applied at the rate of 26.2 g C kg-1 were found to reduce N2O emissions by 34, 54, and 70%, respectively, relative to the control. Within the bioassay, BC and PT amendment resulted in a 38 and 40% increase in dry matter yield (DMY) respectively. Finally, amendment typically resulted in significant net decreases in Olsen P values, while nitrate and ammonium concentrations were high in PT amended soils. In general, PT had the best overall performance. / October 2015

This research addresses the potential ecotoxicity of two emerging carbonaceous materials: C 60 and biochar. The use of these materials is rapidly increasing, as well as their potential for widespread applications. Thus, information about unintended consequences associated the widespread use, incidental or accidental release, and disposal of these emerging materials is needed. The environmental impacts of C 60 , its stable water suspension (nC 60 ), and biochar are assessed here using bacteria and earthworms as model receptors. The antibacterial activity of nC 60 can be mitigated by the presence of natural organic matter as a soil constituent or dissolved in the water column. Sorption to soil might decrease the bioavailability of nC 60 and thus its toxicity to bacteria. Aqueous organic matter also may mitigate nC 60 toxicity. Pristine C 60 showed toxicity to the earthworm's reproduction and was rapidly bioaccumulated by earthworms, although to a lower extent than smaller phenanthrene molecules that are more hydrophobic; thus, the large molecular size of C 60 hinders its bioaccumulation. Less bioaccumulation occurred at higher C 60 concentration in soil, which is counterintuitive and reflects that higher C 60 concentrations that exceed the soil sorption capacity exist as larger precipitates that are less bioavailable. Earthworms avoided soils amended with high concentrations of dry biochar, and experienced significant weight loss after 28-day exposure. The avoidance response was likely to avert desiccation rather than to avoid potential toxicants (i.e., PAHs formed during biochar production by pyrolysis) or nutrient scarcity. By wetting the biochar to field capacity before exposing the worms, this adverse effect can be completely mitigated. Overall, this research provides a foundation for ecotoxicity assessment associated with exposure to C 60 or biochar, and establishes a method by which other emerging materials can be evaluated for their potential environmental impacts.

Dans le cadre de cette recherche, la production de biocharbon par pyrolyse est étudiée à des conditions visant sa valorisation comme biochar (amendement pour le sol), tout en considérant son potentiel comme charbon vert (pour bioénergie ou transformations subséquentes). La production du charbon de biomasse s'est effectuée à l'aide de deux réacteurs à lits fixes de types batch, d'une capacité de 1 et 25 gb.hlbatch, respectivement. Le panic érigé (Panicum virgatum) est la biomasse lignocellulosique qui a été utilisée dans le cadre des tests. Les facteurs de production étudiés sont principalement la température (300, 400 et 500 °C) pour un court temps de résidence en réacteur (2,5 et 5 min) et l'effet de l'usage du CO2 plutôt qu'un environnement plus conventionnel d'azote. L'effet de ces facteurs est étudié par rapport aux caractéristiques physico-chimiques des biocharbons obtenus. Un suivi des produits pyrolytiques complémentaires (bio-huile et gaz) a aussi été effectué. Des extractions de biocharbon par Soxhlet (à l'aide de dichlorométhane) ont été analysées par GC-MS et ont permis l'identification d'une multitude de produits présents dans les biocharbons. Les conditions spécifiques utilisées pour la pyrolyse, entre autres la convection forcée avec taux de chauffe rapide à 300 °C — N2 à l'aide du réacteur 1 glbatch, ont présenté des rendements et propriétés de biocharbon avantageux pour l'amélioration de la productivité du procédé de torréfaction (en comparaison avec des travaux rapportés, notamment ceux de Gilbert et al. [2009]). Les analyses des extractions de charbons de biomasse ainsi que des bio-huiles (par GC-MS), produites à l'aide du réacteur 25g/batch, ont permis d'observer des différences significatives dans les composés obtenus lors de l'usage de CO2 vs N2. Plusieurs composés observés dans les extraits de biocharbons, produits en atmosphère de N2, se retrouvent en quantités moindres dans les extraits de biocharbons produits en atmosphère de CO2 pour des températures communes. À titre d'exemple, le furfural, un composé aromatique commun provenant de la dégradation des glucides, s'est retrouvé uniquement dans les extraits de biocharbons en présence de N2 vs CO2, à 400 °C. Parmi l'ensemble des conditions étudiées (pour les 2 réacteurs), uniquement le naphtalène et des dérivés du naphtalène sont observés comme hydrocarbures aromatiques polycycliques, et ce, uniquement suivant les traitements à 500 °C. L'étude de l'usage du CO2 comme gaz d'entrée en réacteur mena à des différences significatives pour l'ensemble des températures étudiées, et ce, tant pour les biocharbons que pour les produits liquides et gazeux. À 300 °C, en environnement de CO2 comparé à N2, il est possible d'observer une production de bio-huile significativement plus faible (18,0 vs 24,6 %; CO2 vs N2 pour P<0,002), ce qui représente un résultat cohérent avec l'obtention de biocharbon au contenu en composés volatils significativement plus élevé obtenu aux mêmes conditions (0,29 vs 0,35 g composés volatils - biocharbotig biomasse originale; CO2 vs N2 pour P=0, I ). De plus, à 500 °C, un contenu en cendres de biocharbon significativement plus faible a été observé en environnement de CO2 vs N2 (P<0,06). [symboles non conformes]

While the extent of grasslands in Southern Ontario has been greatly reduced, urban and suburban areas provide numerous potential sites for their restoration. Grassland restoration in cities can provide ecological and cultural benefits, but soil conditions may be less than optimal for native species recovery. This thesis explores the use of soil amendments in order to address nutrient deficiency on old-field meadow restoration sites. Five treatments were tested, namely the addition of (1) nitrogenous fertilizer, (2) native legume species, (3) biochar, (4) a combination of the previous three, and (5) an unaltered control. Each treatment was replicated four times on two different test plots in Waterloo Region, Ontario, Canada (Huron Natural Area and Springbank Farm), for a total of 40 subplots. The experimental plots were tilled in the fall of 2011, a randomly selected treatment was applied to each subplot, and then all were seeded with a mix of five native meadow species (2 grass, 2 forb, 1 sedge). Soil samples were taken from each subplot both before treatment application and also at the end of the growing season in 2012, and tested for nutrient levels (N, P, K), pH and organic matter. Species richness, as well as soil temperature and moisture, were regularly monitored over the growing season. In the fall of 2012, above-ground vegetation was harvested to assess accrued biomass. In order to detect differences in means, results were tested using one-way and repeated-measures ANOVAs, where appropriate. Pearson???s product-moment correlations were also employed to test for linear dependence between variables. There were no significant differences between treatments in terms of soil nutrients or pH at either site. At Huron Natural Area, post-treatment biochar-treated subplots had slightly higher levels of organic matter than controls (p=0.095). Values for species richness, above-ground biomass, soil temperature and soil moisture did not vary significantly between treatments. Species richness at Huron Natural Area was positively correlated with 2011 N (r=0.42; p=0.07) and organic matter (r=0.52; p=0.02) levels, while at Springbank Farm it was negatively correlated with 2012 N levels (r=-0.67; p<0.001). Above-ground biomass at Huron Natural Area was positively correlated with 2011 and 2012 P levels (both r=0.52; p=0.02), while at Springbank Farm it was positively correlated with 2011 N, P, K and organic matter, and 2012 N, P and K (all r>0.44; p<0.05). At Huron Natural Area, above-ground biomass was negatively correlated with soil temperature (r=-0.64; p<0.0001) and positively correlated with soil moisture (r=0.38; p=0.1). This study uncovered a strong, but variable, relationship between N concentration and species richness in old-field meadows. Furthermore, productivity was tightly correlated with different soil nutrient concentrations at each study site. The results demonstrate the need for restoration approaches to address local soil conditions on order to be effective. To date, there have been very few studies on meadow restoration, particularly in North America. More, and longer-term, multivariate studies are needed in order to test the effectiveness of different techniques.

This project examines the efficiency of a biochar-producing stove in meeting the needs of households in rural of Kenya. The stove has been tested and evaluated by five household in Embu, Kenya and compared with two other common cooking methods. The main parameters were time consumption, fuel consumption and emissions of carbon monoxide and particulate matter. Usability and energy use efficiency have also been evaluated. Three potential feedstocks have been examined for use in the biochar-producing stove; Grevillea prunings, maize cobs and coconut husks. The biochar-producing stove was well received by the households. It has potential of saving time, it saves fuel and it has a significantly lower level of emissions than other examined stoves. Despite some challenges related to the usability and the handling of the stove, an implementation of the biochar-producing stove can contribute to an alleviation of the women’s burdens, save fuel and contribute to a healthier indoor air climate.

For widespread use of biochar in agriculture and horticulture, it must be ensured that application will neither adversely affect soil and plants, nor exceed legislated contaminant concentrations. The most relevant groups of contaminants in biochar are potentially toxic elements (PTEs), polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOC). In this thesis, the concentrations of these groups of contaminants were analysed in 90 different biochars produced by slow pyrolysis. Subsequently, the concentrations were compared to legislation/guideline threshold values and linked to production conditions. The risk these contaminants pose to plant growth was also assessed, to give recommendations on production of safe biochar. PTEs can neither be formed nor destroyed, which means their presence in biochar is predominantly determined by feedstock type. However, significant levels of Cr, Fe and Ni were introduced into biochar from the furnace steel, whilst PTEs with low boiling points, such as As, Cd and Zn, partially evaporated during pyrolysis. PTEs were not responsible for phytotoxic effects observed for PTE-rich biochars despite biochar’s exceedance of available and total PTE threshold values for soil and soil amendments. Although initial tests were promising, the risk that PTE-rich biochars as amendment for soil and growing media pose, needs further investigation. The PAH concentration in biochar was markedly reduced by increasing carrier gas flow rate, and the type of feedstock also influenced the PAH content. However, there was no clear dependence of pyrolysis temperature on PAH concentrations, which was attributed to PAHs being increasingly formed and evaporated at higher pyrolysis temperatures. Ultimately, condensation of pyrolysis vapours and deposition on biochar was identified as the main risk for biochar contamination with PAHs, as this resulted in elevated concentrations of high-risk, higher molecular weight PAHs. Weaknesses in the pyrolysis unit design, such as cold zones, resulted in elevated concentrations of VOCs, as well as PAHs, in biochar. Comparing concentrations and phytotoxic potential of both compound groups, it was concluded that observed toxic effects were much more likely caused by VOCs in biochars containing both contaminants. Overall, formation of VOCs and PAHs cannot be prevented, but their presence in biochar resulting from retention and deposition can be minimised.

Methane is a potent greenhouse gas with a global warming potential 21 times that of carbon dioxide. Globally, ruminants are the main anthropogenic contributors to methane release to the atmosphere. Methane is produced in the gastrointestinal tract of ruminants, mostly within the rumen by methanogenic archaea. However, methane production represents a loss of 2 to 12% of dietary gross energy for the animal, which could otherwise be available for growth or milk production. Therefore, mitigation of methane production by ruminants could produce both economic and environmental benefits, with more sustainable and energy efficient livestock, and offering a promising way of slowing global warming. Despite extensive research undertaken to find ways of reducing methane emissions from ruminants, progress has been relatively limited. Furthermore, there is still a lack of studies linking rumen microbiology and ruminant nutrition and production. The central purpose of this research was to investigate feed additives to reduce methane emissions and to understand associated changes that occur in the rumen microbiota. For the first experiment (Chapter 2), biochar was evaluated as an antimethanogenic compound for beef cattle. The in vitro gas production technique was used to study the effects of biochar on rumen fermentation and methane production. Overall, methane production was reduced by 5% by the addition of biochar compounds (10 g/kg of substrate). The observed reduction in methane produced was not associated with a change in volatile fatty acid profile suggesting biochar primarily inhibited fermentation. Ammonia concentration was significantly reduced with biochar inclusion. Because different biochars had different effects on methane production, further investigation of relationships between the physicochemical properties of biochars and antimethanogenic effects are necessary. However, due to the small reduction in methane production recorded, research with biochar was discontinued. Encapsulated nitrate was then explored as an antimethanogenic additive and as an alternative non-protein nitrogen source to urea (Chapter 3). The effect of using encapsulated nitrate as a replacement for urea or dietary protein, plus the addition of inorganic sulphur, on enteric methane emissions, nutrient digestibility, nitrogen utilization and microbial protein synthesis from crossbred beef steers were studied. In addition, nitrate toxicity and eating behaviour were investigated. The inclusion of encapsulated nitrate reduced methane production compared to urea and a true protein source, with no adverse effects on rumen fermentation or nitrogen metabolism and no effects with the inclusion of elemental sulphur. The level of addition of encapsulated nitrate (14.3 g nitrate /kg DM) and the time of adaptation chosen for this study (14 days) were adequate to avoid nitrate toxicity. Finally, the effects of adding nitrate inclusion to different basal diets on rumen microbial populations and relationships of these populations with methane production were investigated (Chapter 4). The V4 hypervariable regions of the bacterial and archaea 16S rRNA genes were amplified and sequenced. Effects on microbial population induced by nitrate were dependant on the basal diet but nitrate altered specific archaeal and bacterial OTUs consistently between studies. A direct and strong correlation between some archaea taxonomic groups and OTUs with methane production was observed.

Submitted by ADEMIR RIBEIRO MENDONÇA null (33182912852) on 2018-02-08T15:21:57Z No. of bitstreams: 1 Dissertação de Ademir Ribeiro Mendonça.pdf: 1590154 bytes, checksum: b3e14a029c00dc98399df1a34c748eb1 (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-02-09T12:42:32Z (GMT) No. of bitstreams: 1 mendonça_ar_me_jabo.pdf: 1590154 bytes, checksum: b3e14a029c00dc98399df1a34c748eb1 (MD5) / Made available in DSpace on 2018-02-09T12:42:32Z (GMT). No. of bitstreams: 1 mendonça_ar_me_jabo.pdf: 1590154 bytes, checksum: b3e14a029c00dc98399df1a34c748eb1 (MD5) Previous issue date: 2017-12-08 / Os resíduos de carvão vegetal podem ser utilizados de forma eficiente na agricultura, quando aplicados ao solo, em doses e granulometria adequadas exercem excelente desempenho aos vegetais. O trabalho foi realizado com o objetivo de estudar a interação entre doses e granulometrias de carvão vegetal de Eucalyptus citriodora em solo argiloso, na produção de cenoura híbrida de verão cultivar Mariana. O experimento foi conduzido em casa de vegetação na cidade de Bebedouro, SP. Com 16 tratamentos em esquema fatorial com 5x3+1, sendo 5 granulometrias (1 a 2 mm, 2 a 4 mm, 4 a 8 mm, 8 a 16 mm e 16 a 32 mm) combinadas com 3 doses (25, 50 e 75% em volume de carvão vegetal) mais controle (somente solo), com 4 repetições, em vasos de 8 litros dispostos num delineamento inteiramente ao acaso. Foi avaliada a retenção de água no início e final do ensaio, determinado o crescimento da parte aérea aos 30, 45, 60, 75 e 90 dias após emergência, bem como massa fresca e seca da raiz e parte aérea e dimensões das cenouras na colheita. Observou-se que o melhor desempenho das plantas ocorre na combinação de 50% (v/v) de carvão vegetal com a granulometria de 2 a 4 mm. No início do cultivo as plantas crescem melhor no solo, mas apresentam desempenho superior nos tratamentos com carvão vegetal a partir de 60 dias após emergência. / Charcoal wastes can be used efficiently in agriculture if well managed. With this purpose, this research aimed to study the interaction between dose and size of fine coal particles in clay soil, for carrot production. The experiment was conducted with 16 treatments in a 5x3 + 1 factorial scheme (5 granulometry: 1 to 2 mm, 2 to 4 mm, 4 to 8mm, 8 to 16 mm and 16 to 32 mm, combined with 3 doses:25 , 50% and 75% by volume of coal) plus control (soil only), with 4 replications. Each experimental unit was composed by a pot with 8 L capacity, and the assay was arranged in a completely randomized design. It were determined the water retention in the soil, the plants height measured at 30, 45, 60, 75 and 90 days after plants emergence, the fresh and dry mass of the root and plant shoot and the dimensions of the carrots at harvest. It has been observed that the best performance of the plants occurs in the combination of 50% (v/v) of coal with the fraction of 2 to 4 mm particle size. Plants at initial growth phases develop better in pure soil, however in the final growth phases shows superior performance in treatments containing charcoal.