Browsing by Author "Gessesse, Amare"

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Anaerobic digestion of banana winery effluent for biogas production
(International Journal of Environmental Protection and Policy, 2014-09-30) Bakili, Sophia; Gessesse, Amare; Mtei, Kelvin; Njau, Karoli
he efficiency of banana winery effluent (BWE) in biogas production through improving fermentation process was investigated in this study. The study was conducted in a batch system under mesophilic temperature of 35oC achieved by using controlled thermostat waterbath. Two sets of experiments (labeled as experiment 1 and experiment 2) with five reactors each, were performed in the laboratory. For experiment 1, reactor A was treated as a control with no addition of urea while 1g,2g,3g and 4g of urea were added in reactors B,C,D and E respectively. For experiment 2, different amount of sucrose, that is 0.18g, 0.27g, 0.36g and 0.44g were added in the reactors B, C, D and E correspondingly, and reactor A without sucrose addition was used as the control .Results for experiment 1 revealed that reactor A produced largest volume of biogas (1.93L) followed by reactor B with least amount of urea where 1.37L of biogas was generated. Other reactors produced smaller volume of biogas during the study period. For experiment 2 results indicated large volume of biogas (2.72L) was produced in reactor C with 0.27g of sucrose followed by reactor D (2.71L) with 0.36g sucrose. The biogas produced contained 68.9% - 74.6% methane (CH4). This study concluded that addition of nitrogen source does not increase biogas production from Banana winery effluent while addition of carbon source is important as a source of energy for enhancing C: N ratio for process stability and biogas production.
Isolation and characterization of nitrogen fixing rhizobia from cultivated and uncultivated soils of northern Tanzania
(Scientific Research Publishing, 2014-12-18) Simon, Zephania; Mtei, Kelvin; Gessesse, Amare; Ndakidemi, Patrick
Soil bacteria1 called rhizobia are gram-negative capable to colonize the soil immediately surrounding roots under the influence of the plant “rhizosphere” and reduce atmospheric nitrogen into the form available to plants through nitrogen fixation process. Nitrogen is the most limiting and supplied nutrient to most plants, and the determinant of plant growth. Legumes differ with most plants because they have access to nitrogen from both mineral and symbiotic sources. Small-scale farmers who are the major legume producers in Africa rarely apply fertilizers during legume production. Hence, the crop is largely dependent on fixed nitrogen from native nitrogen fixers. Isolation of rhizobia for legume production has been given a little attention in Africa due to inadequate research or negligence of researchers and unawareness of its potential in legume production as well as lack of an intention from skilled personnel to popularize the technology. Evaluation of effectiveness of isolated rhizobia is essential for inoculants preparation, host specificity recommendation and symbiotic effectiveness. The isolation, determination of their population in the soil and assessing factors affecting their population and testing the effectiveness of native nitrogen fixers with respect to right trap host crop are given a special attention in this review.