Evaluation of thermophilic anaerobic co-digestion of food waste and chicken manure | |
| Author | Wachiranon Chuenchart |
| Call Number | AIT Thesis no.EV-19-25 |
| Subject(s) | Thermophilic bacteria Organic wastes--Recycling Anaerobic bacteria--Treatment Food waste--Environmental aspects |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Enhancement of synergistic effect by co-digestion and accelerating anaerobic reactions by thermophilic condition leads to efficient waste treatment and energy recovery. In this study, Bio-Methane Potential (BMP) test was conducted to arrive at the optimum ratio of feedstock for anaerobic co-digestion. Linear correlation of biogas yield with C/N ratio was observed from the BMP test. The feedstock of food waste and chicken manure mixture in the ratio of 70:30 g VS at C/N ratio of 20 resulted in highest methane yield of 0.64 m3/kg VS, which was 6.67 % higher than food waste alone as the substrate, in the first 12 days of BMP test. The feedstock in optimum C/N ratio of 20 was fed to the bench scale anaerobic co-digestion system of the total capacity of 140 L and a working volume of 87 L in wet condition with 10 % total solids content. The performance of thermophilic anaerobic co-digestion led to higher stability and productivity for different organic loading rates of 1, 2, 3, and 4 kg VS/m3.d. The specific biogas and methane yield tend to decrease when the loading rate was increased. The specific biogas yield from the system was 1.247 m3/kgVS, 1.085 m3/kgVS, 0.912 m3/kgVS, and 1.062 m3/kgVS at OLR of 1, 2, 3 and 4 kgVS/m3‧d. Moreover, the specific methane yield from co-digestion was observed to be 0.795 m3 CH4/kgVS, 0.666 m3 CH4/kgVS, 0.601 m3 CH4/kgVS, 0.655 m3 CH4/kgVS respectively. The percentage increase of specific methane yields in co-digestion compared with mono-digestion was found to be 33.17%, 12.11%, 12.07% and 97.09% when the OLR was increased from 1, 2, 3 and 4 kgVS/m3‧d respectively, due to improved buffering capacity and nitrogen available in the system. The pH value was found to gradually decrease with the increment in organic loading rate. However, the pH of co-digestion was maintained higher than 7 when compared with mono-digestion where it reduced to sub-optimal conditions due to lower organic nitrogen conversion and incomplete anaerobic digestion leaving undegraded VFAs in the system. Moreover, the reduction in FOS/TAC value through co-digestion indicated the higher capacity for organic loading in the anaerobic co-digestion system due to alkalinity from ammonia in chicken manure and nutrient balance by C/N adjustment in the feedstock. |
| Year | 2019 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Visvanathan, C.; |
| Examination Committee(s) | Ekbordin Winijkul;Salam, Abdul P.; |
| Scholarship Donor(s) | Her Majesty the Queen’s Scholarships (Thailand); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2019 |