Anaerobic co-digestion of cassava pulp with pig manure as co-substrate | |
| Author | Basnayake, Basnayake Mudiyanselage Nishantha |
| Call Number | AIT Thesis no.ET-SUD-15-01 |
| Subject(s) | Cassava industry--Waste disposal--Thailand Cassava--Thailand |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management with specialization in Environmental Technology for Sustainable Development jointly offered by the Asian Institute of Technology, Thailand and UNESCO-IHE, The Netherlands |
| Publisher | Asian Institute of Technology |
| Abstract | Cassava pulp (CP) is a major solid waste produced from the starch industries. CP can be converted to the form of methane or other biofuels with the help of a suitable co-substrate in anaerobic digesters. An optimal carbon to nitrogen (C/N) ratio is important for the success of anaerobic digestion. In this research, C/N ratio of CP was adjusted by the addition of pig manure (PM) as the co-substrate in order to enhance methane production. Two experimental reactors (semi continuously operated stirred tank reactors) of capacities 10 and 20 L were evaluated at C/N ratio's of 35 and 25, at various organic loading rates (OLRs <4.0 kgVS/m3·d) for their potential to produce biogas. The reactors were operated at ambient temperatures for 180 days. The results from this study showed that biogas production increased with an increase in the OLR from 1 to 4 kg VS/m3·d, while the methane content varied between 53 and 65% in both the reactors. Maximum methane production was achieved at an OLR of 4.0 kg VS/m3·d. The maximum biogas production rate was ~1.71 and 1.94 L/L.d at an OLR of 4.0 kgVS/m3.day in the 10 L and 20 L reactors, respectively. The highest percentage of VSremoval were 82.11 and 75.79% at an OLR of 2.0 kg VS/m3·d in both the reactors. When the OLR was increased from low to high values, the reactor operation was stable and it showed no inhibition effect from ammonia-nitrogen and VFA, as their concentrations were below the inhibitory concentration levels. Concerning cyanide concentrations in the reactors at different OLRs, their levels did not pose any inhibitory effect on the methanogenic activity nor the biogas production rate. The best C/N ratio for anaerobic co-digestion of CP and PM was found to be 25 (CP:PM=66:34). |
| Year | 2015 |
| 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 | Energy Technology (ET) |
| Chairperson(s) | Annachhatre, Ajit P.; |
| Examination Committee(s) | Lens, Piet N. L.;Thammarat Koottatep;Shipin, Oleg V.;Rene, Eldon Raj; |
| Scholarship Donor(s) | Joint Japan/World Bank Graduate Scholarship Program (JJ/WBGSP);UNESCO-IHE-Asian Institute of Technology; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2014 |