Treatment of fish processing wastewater by purple phototrophic bacteria using anaerobic photobioreactor | |
| Author | Nakassorn Ruangekavit |
| Call Number | AIT Thesis no.EV-25-07 |
| Subject(s) | Fishery processing industries--Environmental aspects Sewage--Biological treatment Biotechnology |
| 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 treatment of wastewater from fish processing wastewater with high salt content poses a major biological treatment problem as it may affect the growth of microorganisms. This study evaluated the treatment of organic and nutrients removal from fish processing wastewater by using purple phototrophic bacteria (PPB) in the anaerobic photobioreactor (AnPBR). In a high salinity environment, PPB has outstanding adaptability and can maintain its ability to remove organic matter and nutrients to some extent. In the first phase, PPB were isolated from water samples from various sources, namely effluent samples from the wastewater treatment plant of Asian Institute of Technology (AIT), water samples from the pond located at AIT golf club, and paddy fields by culturing them in glass tubes containing acetate yeast extract (AYE) culture media. After obtaining PPB, the cultures were enriched and the amount of NaCl in the culture media increased to 2, 3 and 4 g/L gradually. The PPB cultures were then tested in the batch tests serum bottles containing synthetic wastewater and real fish processing wastewater using three infrared (IR) and white light-emitting diodes (LED). The light intensity was 64 W/m2 and the serum bottles were placed on a continuous stirrer at 200 rpm. The fish processing wastewater was subjected to pre-treatment using sedimentation and filtration using a filter paper of pore size 11 μm to minimize the solids and avoid the effect of solids on light availability for the PPB. For the treatment of real pre-treated fish processing wastewater using AnPBR, equipped with four IR lights (each of 64 W/m2) and white LED lights were used with a total intensity of 5,099 lux. The AnPBR was operated at hydraulic retention time (HRT) of 6, 3, and 4 days, respectively, with a total operation period of 87 days. Additionally, the effluent from the AnPBR was treated with treated with microfiltration (MF) membrane with a pore size of 400 nm, operated at 3.1 and 5.6 LMH to determine the feasibility of integrating with AnPBR.The results showed the maximum COD removal efficiency in the batch, AnPBR, and AnPBR+MF were 63.64, 66.67, and 76.5%, respectively. The maximum NH3 removal efficiency in the batch, AnPBR, and AnMBR was 45.42, 23.81, 29.58%, respectively. The maximum PO43- removal efficiency in the batch, AnPBR, and AnPBR+MF were 17.88, 24.73, 53.65%, respectively. The maximum COD, NH3, and PO43- removal efficiency of the AnPBR was at HRT of 6 days and decreased when HRT was reduced to 4 and 3 days. In batch experiments, the biomass productivity was 6.06 mg/L-d. The maximum biomass productivity in the AnPBR experiment was 13.21 mg/L-d. Monod Kinetic parameters of kd, Ks, Y, and µmax for continuing experiments were 0.1117 d-1, 137.2184 mgCOD/L, 0.9658 mgTSS/mgCOD, and 0.1117 d-1, respectively. Monod Kinetic parameters of kd, Y, Ks, and µmax obtained in the batch experiments were 0.5886 d-1, 0.1285 mgTSS/mgCOD, 16.1484 mgCOD/L, and 0.3232 d-1, respectively. The AnPBR was effective in removing COD to a significant degree; however, further research is needed to assess the integration of membrane reactors to increase the biomass in the AnMBR for better nutrient removal. Additionally, the use of white LED lights promoted the growth of microalgae in the reactor. Therefore, it is recommended to utilize only IR light or visible light filters to avoid microalgae growth in the reactors. |
| Year | 2025 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Water Resources and Environmental Engineering (DWREE) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Ghimire, Anish;Cruz, Simon Guerrero (Co-chairperson); |
| Examination Committee(s) | Xue, Wenchao;Anal, Anil Kumar; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2025 |