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In this work, an efficient way of converting the water hyacinth to biocrude oil using magnetite nanoparticles (MNPs) as potential catalysts was demonstrated for the first time. MNPs were synthesised by co-precipitation and used in the hydrothermal liquefaction (HTL) of water hyacinth at different reaction conditions (temperature, reaction time, MNPs to biomass ratio and biomass to water ratio). The best reaction conditions were as follows: temperature— 320, reaction time—60 minutes, MNPs to biomass ratio – 0.2 g/g and biomass to water ratio – 0.06 g/g. HTL in presence of MNPs gave higher biocrude yields compared to HTL in absence of MNPs. The highest biocrude yield was 58.3 wt% compared to 52.3 wt% in absence of MNPs at similar reaction conditions. The composition of biocrude oil was analysed using GC-MS and elemental analysis. GC-MS results revealed that HTL in presence of MNPs led to an increase in the percentage area corresponding to hydrocarbons and a reduction in the percentage area corresponding to oxygenated compounds, nitrogenated compounds and sulphur compounds. Elemental analysis revealed an increase in the hydrogen and carbon content and a reduction in the nitrogen, oxygen and sulphur content of the biocrude when HTL was done in presence of MNPs compared to HTL in absence of MNPs. The nanoparticles were recovered from the biochar by sonication and magnetic separation and recycled. The recycled MNPs were still efficient as HTL catalysts and were recycled five times. The application of MNPs in the HTL of water hyacinth increases the yield of biocrude oil, improves the quality of biocrude through removal of hetero atoms, oxygen and sulphur compounds and is a potentially economical alternative to the traditional petroleum catalysts since MNPs are cheaper, widely available and can be easily recovered magnetically and recycled. This will potentially lead to an economical, environmentally friendly and sustainable way of producing biofuels from biomass.

The study was done to explore the potential of producing fuel briquettes that could meet the need for energy in Uganda, especially Kampala city. The primary objective of this work was to produce fuel briquettes from homogeneous and heterogeneous combinations of carbonized maize cobs, Bamboo poles and charcoal dust. For the primary objective to be achieved, the main activities which were performed included; chopping bamboo poles, sorting maize cobs, carbonization, crushing, binder preparation, mixing, extrusion, drying and quality assessment of the fuel briquettes. The maize cobs and charcoal dust used for this work were purchased from the farmers and charcoal sellers respectively from the districts of Luwero and Nakaseke. Bamboo poles were provided by Divine bamboo group. The homogenous combinations included 100% maize cob char, 100% bamboo char and 100% charcoal dust. Heterogeneous combinations included 75% bamboo char + 25% charcoal dust and 25% bamboo char + 75% charcoal dust. The test results for both homogenous and heterogeneous combinations of fuel briquettes had ranges of moisture content 8% - 11%, Volatile matter 12% - 23%, Ash content 33% - 39%, Heating Value 16 - 22 MJ/Kg, Fixed Carbon 30% - 51% and moisture content 8% - 9%, Volatile matter 13% - 19%, Ash content 27% - 44%, Heating Value 16 - 18 MJ/Kg, Fixed Carbon 30% - 51% respectively. The test results for drop resistance, density and Compressibility strength for both homogeneous and heterogeneous combinations had ranges of 7% - 56%, 214 - 941 kg/m3, 0.077 - 0.544 N/mm2 and 12% - 28%, 869.1 - 958.3 kg/m3, 0.124 - 0.295 N/mm2 respectively. These results were within the ranges reported in the literature especially for the heterogeneous combinations. Therefore, there is the possibility to use bamboo woody feedstock in combination with other agricultural waste feedstock for the production of fuel briquettes. We can increase the quality and production of fuel briquettes by using alternative feedstock sources rather than degrading the environment through deforestation.

This paper presents results of soil analysis for samples extracted from Makerere University Agricultural Research Institute Kabanyolo. The study was aimed at ascertaining the suitability of MUARIK soils for fruit (pineapple, passion fruit and watermelon) and vegetable (cabbage, eggplant, tomato and pumpkin) growth, yield and maturity. Soil morphological, physical and chemical properties were probed by excavating a 1.86 meter soil profile pit and sampling soils in 9 equidistant locations at MUARIK. The soil morphology and physical properties were described using the Munsel colour chart and USDA classification system while chemical parameters were determined in Makerere University Soil Laboratory following procedures described by Okalebo et al. [1]. Three pedon layers (RSK-H1, RSK-H3 and RSK-H5) had gradual boundaries while RSK-H4 was continuous. However, RSK-H2 and RSK-H6 had abrupt boundary layers. The texture of the profiles was clayey (52%). The soils were acidic with a pH of 6.08 (sub soil) to 6.12 (top soil). On comparison with standard requirements for target fruits and vegetables, the site was deficient in most of the minerals including P (8.88-12.42 pmm), Ca (6.46-7.92 pmm), K (0.06-0.47 pmm), Mg (1.37-1.70 pmm), Na (0.17-0.23 pmm), N (0.18-0.19 pmm), and soil organic matter (4.53%-4.81%). Sand and clay had the highest negative significant correlation (r = &#450.94, p < 0.01) in the top soil. The highest positive significant correlation was observed between Ca and Mg both in the topsoil (r = 0.96, p < 0.01) and subsoil (r = 0.99, p < 0.01). MUARIK is suitable for growing cabbage and pumpkin. However, for improved growth, yields and maturity, the soils should be amended with manure (watermelon), lime (passion fruit and tomato) and sulphur (eggplant and pineapples).