Multi-stage anaerobic digestion of animal waste | |
| Author | Raweewan Piyapisuit |
| Call Number | AIT Thesis no. EV-84-10 |
| Subject(s) | Sewage sludge digestion Animal waste |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | Bench scale experiments on methane production from a mixture of cow dung and pig manure were conducted in batch, single and multi-stage digestion systems. The mixture was composed of 95 % cow dung and 5% pig manure. The solid to water ratio of influent mixture used for batch. and 111ultistage digestion study was 8:92, respectively, where as it varied for single-stage due to various dilution applied to obtain constant VOLR. Batch system was to determine the ultimate methane yield and refractory fraction of the influent remixture. Single and multi-stage digesters were operated on semi-continuous basis. VOLR to single-stage were maintained at 2 and 3 kg TVS/m 3/day and HRT varied as 5, 15 a nd 25 days tor each VOLB. For the multi-stage digesters, various combinations of HRT and VOLR in first and second stage were conducted to investigate the maximum gas production. The ultimate methane yield was found. to be o. 325 m3 CH4-/kg TVS added and refractory fraction of 0.58. In the single-stage digestion system, gas production was observed to increa.se with in creasing the HRT and for a given HBT gas production was higher for a higher VOLR. The maximum CH4 production and TVS reduction recorded was 0.1845 m3/m3/day and 24.22 %, respectively, at 25 days l:IRT of 3kg TVS/ m3/day VOLR. In multi-stage digestion systems, the maximum biogas production rate of o.5 m3/m3/ day or U.35 m3CH4 /day were obtained at the VOLR of 12.55 kg TVS/m3/day and overall. HRT of 10 days (5 days in first stage and 5 days HRT in second stage). The overall maximum TVS reduction of 42 3 was obtained at the overall HRT of 30 days (5 days in the first stage and 25 days HRT in the second stage) In both single and multi-stage digestion system , the die-offs o f the fecal coliform and fecal streptococci varied from 14 to 99 %. However despite of the nigh percentage reduction, effluent t from both the system was round to contain high densities of bacteria. The multi-stage digestion system was observed to give higher biogas production yield than the single-stage system. The biogas production rate (m3 /m3/day) from multi-stage system was 2-3 times higher than that from the single-stage system. |
| Year | 1984 |
| Type | Thesis |
| School | School of Environment, Resources, and Development |
| 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) | Chongrak Polprasert |
| Examination Committee(s) | Orth, Hermann M. ; Ohgaki, Shinnichiro |
| Scholarship Donor(s) | Carl Duisberg Gesellschaft, e.v. (CDG) Federal Republic of Germany |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1984 |