Optimization of algal-bacterial photobioreactor for the treatment of septic tank effluent and carotenoids production | |
| Author | Wipharat Khongphu |
| Call Number | AIT Thesis no.EV-20-14 |
| Subject(s) | Septic tanks Microalgae--Biotechnology Sewage--Purification--Biological treatment |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | The nutrient constituents contained in septic tank effluent have potential to cultivate of microalgae in photobioreactor (PBR). The abilities of microalgae are not only nutrient uptake but also carotenoids production. This study aims to examine the treatment performance of PBR treating septic tank effluent and to determine carotenoids production in Coelastrella sp. The effects of illumination and stress period on total carotenoids production of Coelastrella sp. were examined in the steady stage condition. Using different light intensities: high (500 µmol/(m2.s)), medium (300 µmol/(m2.s)), and low (100 µmol/(m2.s)). The results, indicated that the blue LED light (wavelength = 440-480 nm) at the high light intensity were found to be best lighting conditions of the PBR for treating septic tank effluent and producing high carotenoid in algal biomass. The best stress period of the blue wavelength of high intensity for treatment performance carotenoid production was 8 days which resulted 74%, 90% and 62% of COD, TN and TP removal efficiencies, respectively; while the total carotenoids and biomass productivity were 3.81 mg/(L.d) and 11 mg/(L.d) in the blue light PBR. Although the PBRs were operated with actual septic tank effluent without sterilization, the Coelastrella sp. was still observed to be predominant species. Furthermore, Stover-Kincannon model was applicable for determining kinetic constants for COD, TN and TP removals in the PBR systems. This study suggested that the PBR with blue lights could be applied for treating septic tank effluent and simultaneously enhancing total carotenoids in the produced biomass. |
| Year | 2020 |
| 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 (EV) |
| Chairperson(s) | Thammarat Koottatep; |
| Examination Committee(s) | Chongrak Polprasert;Visvanathan, Chettiyappan; |
| Scholarship Donor(s) | Royal Thai Government;Bangchak Petroleum Public Company Limited, Thailand; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2020 |