Water hyacinth, E. crassipes, an invasive water weed thrives in fresh water bodies causing serious\nenvironmental problems. In Kenya the weed has invaded Lake Victoria and poses great socioeconomic\nand environmental challenges. Currently the weed is harvested from the Lake and left in\nthe open to rot and decay leading to loss of aesthetics, land and air pollution. There is therefore\nneed for development of value addition and economic exploitation strategies. The aim of the study\nis to assess the potential for utilization of the weed as a renewable energy resource for biogas production.\nSamples were collected from Lake Victoria, pulped and blend with cow dung at a ratio of\n3:1 as inoculum. The resultant mixture was mixed with water at a ratio of 1:1 and fed into a 6 m3\ntubular digester. The digester was recharged with 20 kg after every three days. The temperature,\npH variations, gas compositions, upgrading and gas yields were studied. The temperature ranged\nbetween 22.8 - 36.6 and pH 7.4 - 8.5. Biogas was found to contain 49% - 53% methane (CH4),\n30% - 33% carbon dioxide (CO2), 5% - 6% nitrogen (N2) and traces of hydrogen sulphide (H2S).\nThe biogas was upgraded using solid adsorbents and wet scrubbers increasing the methane content\nby up to 70% - 76%. The upgraded gas was used to power internal combustion engines coupled\nwith an electricity generator and direct heat applications. The study concludes that E. crassipes\nis a potential feedstock for biogas production especially in areas where it is abundant.
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