Investigation of Factors Affecting Biogas Production from Cassava Peels by Fractional Factorial Design Experimental Methodology

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.