Enhancement of organic matter and total nitrogen removal in a membrane aerated biofilm reactor using bio-carriers | |
| Author | Premarathna, Nandana Hewawasamge Sajith Madhawa |
| Call Number | AIT Thesis no.EV-19-13 |
| Subject(s) | Water--Purification--Membrane filtration Wastewater--Treatment Membrane reactors |
| 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 | In this study, a modified Membrane Aerated Biofilm Reactor (MABR) which used PVAGel as bio-carriers was operated to enhance the Total Nitrogen (TN) removal efficiency when treating low-strength domestic wastewater (4 ≤ COD/N ≤ 7). The operation was conducted at different HRTs (12h, 9h and 6h) and different COD/N ratios (5, 5.5, 6, 6.5 and 7). Two different MABRs with Polydimethylsiloxane (PDMS) and MHF 130 Expanded Polyethylene (EPE) membrane modules were operated in parallel to treat synthetically prepared low-strength domestic wastewater. The MABR containing PDMS modules was modified by adding PVA-Gel beads (10% of volume of the reactor) into the reactor as biocarriers to support additional denitrifier growth. In both the reactors, the COD removal performance was always above 90% and had slight variations throughout the whole experimental duration. The COD removal performance was not affected by the addition of PVA-Gel bio-carriers (10% of reactor volume), by changing the COD/N ratio (5 to 7 stepwise) or by changing the HRT (12h to 9h stepwise). In the MABR with PDMS membrane modules, the nitrification performance increased by 14% while the TN removal performance increased by 13.4% after the addition of PVA-Gel bio-carriers. In addition, it had a maximum TN removal of 68.63% at 12h HRT and COD/N ratio of 6. The HRT of 12h in this study, which is low compared to previous studies is attractive when it comes to commercial and large-scale applications, due to less space requirement and high rate of treatment. Another important observation was that, the nitrification rate in the MABR with the PVA-gel had an upward trend when the COD/N ratio was increased or/and when the HRT was reduced in contrast to a conventional MABR. In addition, the MABR with the PDMS membrane modules (with PVA-Gel) required low biofilm controlling compared to the MABR with the MHF 130 EPE membrane module. Since, biofilm thickness control is still one of the major issues in using MABRs, this study will pave a new way to address that issue in the future using PVA-Gel bio-carriers. All these reasons concluded that the adding of PVA-Gel which contain denitrifying bacteria enhanced the overall MABR performance. |
| Year | 2019 |
| 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) | Visvanathan, C.; |
| Examination Committee(s) | Xue, Wenchao;Thammarat Koottatep; |
| Scholarship Donor(s) | Kurita Water and Environment Foundation, Japan; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2019 |