Suchergebnisse

Leaves of Mangifera indica (MI, mango leaves) and Manihot utilissima (MU, cassava leaves) are available in tropical regions and are the most accessible vegetable waste of Kinshasa Province, capital of the Democratic Republic of Congo. The main objective of this study was to investigate the optimization of methane production from MI and MU leaves in co-digestion by BMP tests at 30°C. The yields for 100 days achieved from the anaerobic digestion of up to 61.3 g raw matters in 1 l medium were 0.001 l/g and 0.100 l CH4/g volatile solids of MI and MU leaves respectively. By comparison to MI, MU leaves are generally characterized by a higher in mineral content. The TOC and TKN related to MU were slightly lower and 6-fold higher respectively than the corresponding levels in MI. Therefore, the carbon to nitrogen ratio C/N, i.e. about 7, was significantly different regarding the range from 20 to 30 commonly recommended for optimal anaerobic digestion. The reason why, MU and MI leaves were mixed for correcting their C/N ratios. Therefore, leaves yields of methane production in relation to volatile solids were improved. The MU and MI yields in the mixture of MU (75%) and MI (25%) have increased; they were 0.121 l/g and 0.114 l CH4/g volatile solids respectively or nearly 1-fold higher and nearly 100-fold higher respectively than the corresponding leaves in the isolated digestion. ; Peer reviewed

[en] Leaves of Mangifera Indica (MI, mango leaves) and Manihot Utilissima (MU, cassava leaves) are available in tropical regions and are the most accessible vegetal wastes of Kinshasa, capital of Democratic Republic of Congo. These wastes are not suitably managed and are not rationally valorized. They are abandoned in full air, on the soil and in the rivers. They thus pollute environment. By contrast, they can be recuperated and treated in order to produce methane (energy source), organic fertilizer and clean up the environment simultaneously. The main objective of this study was to investigate methane production from MI and MU leaves by BMP tests at 30^circC. The yields achieved from the anaerobic digestion of up to 61.3 g raw matter in 1 l medium were 0.001 l/g and 0.100 l CH4/g volatile solids of MI and MU leaves, respectively. The yield of MU leaves was in the range mentioned in the literature for other leaves because of a poor presence of bioactive substrates, and low C/N ratio. This methane yield corresponded to 7% of calorific power of wood. By contrast, the methane yield from MI leaves was almost nil suggesting some metabolism inhibition because of their rich composition in carbon and bioactive substrates. Whereas classical acidogenesis and acetogenesis were recorded.Therefore, methane production from the sole MI leaves seems unfavorable by comparison to MU leaves at the ambient temperature in tropical regions. Their solid and liquid residues obtained after anaerobic digestion would be efficient fertilizers. However, the methane productivity of both leaves could be improved by anaerobic co-digestion. ; info:eu-repo/semantics/published

Leaves of Mangifera Indica (MI, mango leaves) and Manihot Utilissima (MU, cassava leaves) are available in tropical regions and are the most accessible vegetal wastes of Kinshasa, capital of Democratic Republic of Congo. These wastes are not suitably managed and are not rationally valorized. They are abandoned in full air, on the soil and in the rivers. They thus pollute environment. By contrast, they can be recuperated and treated in order to produce methane (energy source), organic fertilizer and clean up the environment simultaneously. The main objective of this study was to investigate methane production from MI and MU leaves by BMP tests at 30°C. The yields achieved from the anaerobic digestion of up to 61.3 g raw matter in 1 l medium were 0.001 l/g and 0.100 l CH4/g volatile solids of MI and MU leaves, respectively. The yield of MU leaves was in the range mentioned in the literature for other leaves because of a poor presence of bioactive substrates, and low C/N ratio. This methane yield corresponded to 7% of calorific power of wood. By contrast, the methane yield from MI leaves was almost nil suggesting some metabolism inhibition because of their rich composition in carbon and bioactive substrates. Whereas classical acidogenesis and acetogenesis were recorded. Therefore, methane production from the sole MI leaves seems unfavorable by comparison to MU leaves at the ambient temperature in tropical regions. Their solid and liquid residues obtained after anaerobic digestion would be efficient fertilizers. However, the methane productivity of both leaves could be improved by anaerobic co-digestion. ; Peer reviewed