Investigation of Factors Affecting Biogas Production from Cassava Peels by Fractional Factorial Design Experimental Methodology
M. T. Nkodi *
Department of Petrochemistry, Faculty of Gas, Oil and New Energies, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
K. C. Mulaji
Department of Chemistry and Industry, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
M. R. Mabela
Department of Mathematics and Computer Science, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
S. J. Kayembe
Department of Chemistry and Industry, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
M. E. Biey
Department of Environmental Science, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
G. Ekoko
Department of Chemistry and Industry, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
K. M. Taba
Department of Chemistry and Industry, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
*Author to whom correspondence should be addressed.
Abstract
The aim of this study was to investigate parameters affecting biogas production from cassava peels by using fractional factorial design method. The parameters studied were initial pH, organic loading rate, particle size and co-substrate type. Eight biodigesters (TH1, TH2, TH3, TH4, TH5, TH6, TH7 and TH8) in duplicate were performed to produce biogas from cassava peels. The experimental results showed that organic loading rate (X2), particle size (X3) and co-substrate (X4) have significant effect on the yield of biogas. The full mathematical model developed includes two main effects (X2 and X3) and three interactions (X1X2, X2X3 and X1X2X3). Reduced model was introduced in the present study. The highest volume of biogas (2252 mL) was obtained in digester TH2 under the following conditions: initial pH 7.8, 5% TS, ≤2 mm of particle and urea as co-substrate, while digester TH8 had slightly low biogas yield (2129.5 mL). Thus, the best conditions to produce biogas from cassava peels are those of TH2.
Keywords: Biogas production, cassava peels, fractional factorial design, urea.