Browsing by Author "Maghanga, Justin"

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  • Publication
    Publication
    Polycyclic Aromatic Hydrocarbon Emissions Arising from Domestic Combustion: A Kenyan Case Study
    (Research Gate, 2022-10-07) Forbes, Patricia; Osano, Aloys; Maghanga, Justin; Munyeza, Chiedza; Chaka, Bakari; Adeola, Adedapo; Nsibande, Sifiso
    A vast number of people in developing countries rely on solid fuels, including wood and charcoal, for domestic energy supply. We have studied the gaseous polycyclic aromatic hydrocarbon (PAH) concentrations in Kenyan homes in order to better understand the potential health risks associated with domestic combustion practices and to advise mitigation strategies. A comprehensive survey was conducted to elucidate the complex and multi-faceted factors governing fuel use in Kenyan coastal and inland regions. Results showed an almost equal distribution in fuel type usage between firewood, charcoal, kerosene and liquid petroleum gas (LPG). In rural areas, three-stone stoves were still predominant, whilst cleaner devices burning kerosene and LPG were used more widely in urban communities. Indoor air was subsequently sampled in a range of urban and rural households using portable polydimethylsiloxane sampling tubes. These were extracted using the plunger assisted solvent extraction (PASE) technique, followed by GC-MS analysis of the U.S. Environmental Protection Agency (EPA) priority PAHs. Total PAH concentrations in samples collected varied considerably (0.82-173.69 µg/m 3), which could be attributed to differences in fuel type, combustion device, climate, and nature of the households. Higher PAH concentrations were found in rural homes, although ambient PAH concentrations were higher in urban environments, likely due to traffic contributions and population density. Toxicity equivalent quotient values varied widely between households and emphasised the importance of good combustion practices to minimise human exposure.
  • Publication
    Publication
    The Influence of Biocatalytic Plant Extracts on Biogas Production from Kitchen Wastes at Cryo-mesophilic Temperature Regimes
    (Science Publishing Group, 2019-01) Chaka, Bakari; Osano, Aloys; Maghanga, Justin; Magu, and Martin
    Radicalization in waste-to-energy systems are on the rise to meet human energy demands. Biogas generation from kitchen wastes is one such scheme, though affected by poor yields and methane levels at low temperatures. In this research, biocatalytic extracts with fermentative properties were hereby assessed on their potential to fasten these processes and increase the biogas yield at ambient temperatures. The variations in kitchen waste substrate anaerobic parameters and elemental composition as well as biogas yields and methane levels were monitored in a 28-day retention period. Three 40-liter batch and unstirred bio-digesters containing biocatalysts Terminalia b., Acanthaceae spp. and a control setup were used. The results indicated rapid saccharification rates in the samples with additives. Terminalia b. additives exhibited high volatile solids hydrolysis rate of 98.3% followed by Acanthaceae spp. (50.8%) and control sample (29.4%). Similar trends were observed in organic carbon reduction as the levels of nitrogen, phosphorus and sulfur linearly increased. The biocatalysts did not affect substrate pH, volatile fatty acids and alkalinity levels. Terminalia b. sample produced 2.32 folds higher while Acanthaceae spp. sample produced 1.375 folds higher than the control sample. Terminalia b. methane levels were highest (45.475±0.922%) followed by the control sample (41.750±1.401) and Acanthaceae spp. sample (39.275±0.263%) after 28-day retention period at 19.5±0.5°C. Use of these biocatalysts in biofuel synthesis can thus optimize biogas production leading to greener economies.