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The current threats of climate change connected to the unsustainable consumption of fossil resources paired with an increasing world population demands the exploration of alternative raw materials for the production of food, fuel and specialty chemicals. Agricultural waste streams present suitable sources due to their availability in large quantities at low costs without competing with current food production. Among them are oat hulls, the outer protective layer of the oat grain, which are currently mostly disposed via incineration. In this work, oat hulls were found to be an excellent source of dietary fibres as they are rich in lignocellulose (up to 83 % of its dry weight) and the hemicellulose arabinoxylan (35 %). Arabinoxylan has been identified as a promising dietary fibre with anti-inflammatory properties. The hull’s outstanding composition, however, is threatened by the presence of extreme weather events such as unusual heat and low precipitation during its growth phase leading to a loss of 25 % of its lignocellulose and 31 % of its hemicellulose content. Simultaneously, the separation of grain and hull is impeded leading to lower industrial grain yields and higher starch contamination of the hull fraction.Despite its excellent chemical composition for the production of dietary fibres, its optical properties are rather unfavourable in the eyes of consumers due to its dark coloration which challenges its seamless inclusion in a variety of products. In this work, a mild and effective bleaching method was developed using alkaline hydrogen peroxide. This method is suitable for the production of a white insoluble dietary fibre product with a CIE L* (lightness parameter) value of above 85, while retaining the hull’s lignocellulosic content. The method is robust yielding similar bleaching results despite large raw material batch variation caused by different weather conditions during the oat’s growth phase.For oat hulls to be used as source for soluble dietary fibre

This research evaluated the use of spent coffee grounds (SCG) and oat hulls as precursors for activated carbon applied for organic matter removal from leachate, a pollutant wastewater produced by landfills. These precursors were selected based on their global commercial significance. The high demand for the beverage coffee is directly proportional to the generation of SCG as organic waste. Similarly, oat is a popular cereal consumed worldwide, and its industrial processing generates hulls as organic waste. The activated carbon samples were produced by chemical activation with phosphoric acid (H3PO4), using distinct impregnation ratios: 50 and 100 % for SCG, and 60 and 100 % for oat hulls; followed by pyrolysis in an inert atmosphere, at 350 and 500 °C. The feasibility of the tested precursors as adsorbents was initially assessed in experiments with synthetic leachate. Afterwards, the results from the initial tests were compared with those obtained in real leachate treatment. The studies described in this thesis showed that the impregnation ratios and pyrolysis temperatures interfered with the surface areas of the formed adsorbents, consequently affecting the organic matter removal from leachate. Both oat hulls and SCG were successfully recovered as activated carbon, and efficiently treated synthetic and real leachate, removing more than 90 % of the organic matter. Therefore, this study highly encourages the use of SCG and oat hulls as precursors for activated carbon production and their application to treat leachate.

This research evaluated the use of spent coffee grounds (SCG) and oat hulls as precursors for activated carbon applied for organic matter removal from leachate, a pollutant wastewater produced by landfills. These precursors were selected based on their global commercial significance. The high demand for the beverage coffee is directly proportional to the generation of SCG as organic waste. Similarly, oat is a popular cereal consumed worldwide, and its industrial processing generates hulls as organic waste. The activated carbon samples were produced by chemical activation with phosphoric acid (H3PO4), using distinct impregnation ratios: 50 and 100 % for SCG, and 60 and 100 % for oat hulls; followed by pyrolysis in an inert atmosphere, at 350 and 500 °C. The feasibility of the tested precursors as adsorbents was initially assessed in experiments with synthetic leachate. Afterwards, the results from the initial tests were compared with those obtained in real leachate treatment. The studies described in this thesis showed that the impregnation ratios and pyrolysis temperatures interfered with the surface areas of the formed adsorbents, consequently affecting the organic matter removal from leachate. Both oat hulls and SCG were successfully recovered as activated carbon, and efficiently treated synthetic and real leachate, removing more than 90 % of the organic matter. Therefore, this study highly encourages the use of SCG and oat hulls as precursors for activated carbon production and their application to treat leachate.

Litter moisture contents vary greatly between and within practical poultry barns. The current experiment was designed to measure the effects of 8 different dietary characteristics on litter and excreta moisture content. Additionally, free water content and water activity of the excreta and litter were evaluated as additional quality measures. The dietary treatments consisted of nonstarch polysaccharide content (NSP; corn vs. wheat), particle size of insoluble fiber (coarse vs. finely ground oat hulls), viscosity of a nonfermentable fiber (low- and high-viscosity carboxymethyl cellulose), inclusion of a clay mineral (sepiolite), and inclusion of a laxative electrolyte (MgSO4). The 8 treatments were randomly assigned to cages within blocks, resulting in 12 replicates per treatment with 6 birds per replicate. Limited effects of the dietary treatments were noted on excreta and litter water activity, and indications were observed that this measurement is limited in high-moisture samples. Increasing dietary NSP content by feeding a corn-based diet (low NSP) compared with a wheat-based diet (high NSP) increased water intake, excreta moisture and free water, and litter moisture content. Adding insoluble fibers to the wheat-based diet reduced excreta and litter moisture content, as well as litter water activity. Fine grinding of the oat hulls diminished the effect on litter moisture and water activity. However, excreta moisture and free water content were similar when fed finely or coarsely ground oat hulls. The effects of changing viscosity and adding a clay mineral or laxative deviated from results observed in previous studies. Findings of the current experiment indicate a potential for excreta free water measurement as an additional parameter to assess excreta quality besides total moisture. The exact implication of this parameter warrants further investigation.