Cultivating conditions optimization of the anaerobic digestion of corn ethanol distillery residuals using response surface methodology

• Published in: Central European journal of chemistry Vol. 12; no. 8; pp. 868 - 876
• Main Authors: Gyenge, László, Ráduly, Botond, Crognale, Silvia, Lányi, Szabolcs, Ábrahám, Beáta
• Format: Journal Article
• Language: English
• Published: Heidelberg Versita 01.08.2014; De Gruyter
• Subjects: Anaerobic digestion optimization; Biochemistry; Biological and Medical Physics; Biophysics; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Corn; Corn DDGS; Distillation; Ethanol; Ethyl alcohol; Geochemistry; Inoculum; Inoculum type; Methane; Optimization; Process conditions; Response surface methodology; Riccce 18; Process conditions; Inoculum type; Anaerobic digestion optimization; Response surface methodology; Corn DDGS
• ISSN: 1895-1066; 2391-5420; 1644-3624; 2391-5420
• DOI: 10.2478/s11532-014-0542-2

This study investigated the individual and interactive effects of three factors — temperature, inoculum/substrate ratio (ISR) and inoculum typology — on the anaerobic digestion of corn ethanol distillery wastewater. Biochemical methane potential assays planned with factorial design with two independent quantitative variables on three levels (ISR: 1:1, 2:1 and 3:1; temperature: 30°C, 33.5°C, 37°C) and one independent qualitative variable (inoculum type: suspended, granular, mixed) have been performed. Response Surface Methodology has been used to study the effect of the factors with the aim of maximizing the specific methane yields (Y CH4 ) obtainable with this substrate. The results show that all three investigated factors influence in a significant matter the Y CH4 , the ISR having the strongest effect on it. The temperature has significant influence on the Y CH4 only in combination with high ISR values. The optimal conditions for the maximum Y CH4 (551 mL CH 4 g −1 VS added ) have been found at 37°C operating temperature, ISR=3:1 and using granular inoculum. These conditions gave rise to a 4-fold increase of Y CH4 with respect to the worst combination of factors (Y CH4 =129 mL g −1 VS added for the suspended inoculum type, at 30°C and ISR=1:1). The results improve the knowledge on the digestion of this substrate, providing information for successful process up-scaling.