Electroconductive moving bed-membrane bioreactor for enhanced nutrient removal in domestic wastewater | |
| Author | Nutkritta Udomkittayachai |
| Call Number | AIT Thesis no.EV-20-05 |
| Subject(s) | Membrane reactors Wastewater--Treatment Biotechnology |
| 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 | Membrane Bioreactor (MBR) becomes an attractive technology for wastewater treatment due to its various advantages. However, efficient nutrient removal in MBR remains a major challenge. In this study, an Electroconductive Moving Bed Membrane Bioreactor (EcMBMBR) was proposed for simultaneous removal of organics and nutrient from domestic wastewater, as well as membrane fouling mitigation. An EcMB-MBR was composed of a submerged MBR, electrochemical process, and free-floating conductive media. The conductive media were introduced to reduce energy consumption. It was assumed that conductive media could improve TN removal and membrane fouling mitigation in combination with the electrochemical process. The results showed that COD, TN, and TP removal in an EcMB-MBR was up to 97.1 ± 1.36%, 88.9 ± 3.94%, and 99.0 ± 0.87%, respectively, in comparison with those of 93.4 ± 1.43%, 65.3 ± 5.06%, and 20.4 ± 10.7% in a conventional MBR. Meanwhile, a total membrane resistance reduction of about 26.7% was observed in an EcMB-MBR. The extracellular polymeric substances measurement indicated that EcMB-MBR was able to reduce 28.8% of organic foulants, especially bound EPS. An optimum operating condition was determined with electricity exposure time at 1:1 (10 minON/10 min-OFF) and a DC current density of 15 A/m2. A preliminary cost analysis showed that an additional operating cost of 2.60 Baht/m3 was needed at the optimum condition, which was acceptable considering the operating cost of a conventional MBR. Furthermore, the integrated functions of electric current and conductive media were explored to fully understand the working mechanism in the proposed system. It was found that the conductive media reduced 21% of the electrical resistance in the mixed liquor at a selected packing density of 0.18. Nitrate nitrogen reduction was obviously enhanced by the occurrence of denitrification process due to the presence of electric current and conductive media. It has 5.2% of nitrate nitrogen remaining in the effluent of EcMB-MBR when compared with 29.5% in MBR. Meanwhile, membrane fouling was minimized through both mechanical scouring and electrochemical process. |
| 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 and Management (EV) |
| Chairperson(s) | Xue, Wenchao |
| Examination Committee(s) | Visvanathan, C.;Salam, P. Abdul |
| Scholarship Donor(s) | Her Majesty the Queen’s Scholarships (Thailand) |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2020 |