The focus of this study was the reuse of red algal ethanol fermentation residue as feedstock for anaerobic digestion. Levulinic acid and formic acid, the dilute-acid hydrolysis byproducts, inhibited methanogenesis at concentrations over 3.0 and 0.5. g/L, respectively. However, the inhibition was overcome by increasing inoculum concentration. A series of batch experiments with the fermentation residue showed increased methane yield and productivity at higher inoculum concentration. The maximum methane conversion rate of 84.8% was found at 5. g COD/L of fermentation residue at 0.25. g COD/g VSS of food-to-microorganism (F/M) ratio. The red algal ethanol fermentation residue can possibly be used as a feedstock in anaerobic digestion at appropriate concentration and F/M ratio.
Bibliographical noteFunding Information:
This work was supported by a Grant ( 09-FN-1-0014 ) from Korea Institute of Energy Technology Evaluation and Planning, Ministry of Knowledge Economy , Republic of Korea and a Grant ( JA-12-0001 ) from Korea Institute of Industrial Technology , Republic of Korea, and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (MOST) (2011-0014666).
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Renewable Energy, Sustainability and the Environment
- Waste Management and Disposal