Bioethanol and briquette production as an alternative control measure of water Hyacinth on lake Victoria.
Uganda’s energy sector is still predominantly dependent on biomass that contributes 88% of the total primary energy consumed through firewood, charcoal and crop residues. This widespread dependence on biomass energy resources has resulted in rapid forest depletion estimated to be 0.8% annually, equivalent to a loss of about 50,000 hectares of forest per year. Thus, promoting the use of other efficient biofuels alternatives that is, bioethanol and briquettes derived from Water Hyacinth (WH) is an attractive. WH is a proven biomass resource as a viable biofuel feedstock due to the presence of cellulose, hemicellulose and lignin in water hyacinth makes it a viable biofuel feedstock. In Uganda, WH is in abundance and has created vast disturbance in navigation and power generation on Uganda’s waters especially Lake Victoria. Investment has been directed towards the control of WH through mechanical, physical and biological techniques. Fresh WH samples were collected and tested for dry matter content, ash content, organic matter, organic carbon, lignin content, cellulose content, hemicellulose content and total reducing sugars. Different pre-treatment methods of WH (acid, alkali and yeast) were used for the production of bioethanol. The WH was also carbonised and compacted with different binders including cassava starch, anthill soil and cow-dung for production of briquettes. The calorific values of both bioethanol and briquettes were determined. The physical and chemical properties of fresh WH were determined to be 20.20%, 24.63%, 27.87%, 15.13%, 3.80%, 96.63% and 96.35% for lignin content, cellulose content, hemicellulose, dry matter, ash content, organic matter and organic carbon, and the percentage content respectively. The percentage bio-ethanol yields were 29.5 % for acid hydrolysed ferment, 18% for alkali hydrolysed ferment and 20.5 % for enzyme hydrolysed ferment. The calorific values of bioethanol and briquettes samples of cassava starch, anthill soil, cow dung and no binder were found to be 26.4 MJ/kg and 8.061 MJ/kg, 2.076 MJ/kg 9.034 MJ/kg, 7.174 MJ/kg respectively. It was concluded that fermentation of water hyacinth using acid hydrolysis pre-treatment yields an optimum process for ethanol production. The bioethanol produced from water hyacinth was of good quality and fit for use as a cooking fuel. The briquettes produced using cow dung and cassava starch binder had the best quality compared to those of anthill soil binder and no binder. The study recommends the production of briquettes from mixture of water hyacinth and cow dung and its utilization could be advocated since its usage as solid biofuel, will alleviate the challenges caused by water hyacinth.