Application of UV LEDs for turbid wastewater disinfection | |
| Author | Zeng, Chenghui |
| Call Number | AIT Thesis no.EV-14-02 |
| Subject(s) | Water--Purification--Disinfection Water--Purification--Ultraviolet treatment |
| 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 |
| Series Statement | Thesis ; no. EV-14-02 |
| Abstract | UV LEDs was thought to be a good alternative to conventional UV lamp. In this study, the impact of turbidity on the disinfection performance of UV LEDs (282 nm) was examined. Inactivation of Escherichia coli (E. coli) and total coliform was compared based the exposure time. Actinometry methods have been applied to measure the UV fluence in the reactor, including iodide-iodate and ferrioxalate actinometer. Both synthetic and real wastewater have been used to conduct the disinfection test. Turbidity of synthetic wastewater was 27, 70, 113, and 156 NTU and that for real wastewater was 57, 72, 86, and 130 NTU. Irradiance of UV LEDs was found to be 0.4282 mW/cm² (iodide-iodate) and 0.382 mW/cm² (ferrioxalate). In synthetic wastewater of 27, 70, and 113 NTU, 5 log-reduction of E. coli could be achieved and the inactivation kinetics was a first order reaction. However, in real wastewater of 72, 86 and 130 NTU, only 3 log-reduction of both total coliform and E. coli could be achieved. The reason is that part of the coliform bacteria or E. coli in real wastewater was attached to the particles. These particles can protect the bacteria from being exposed to UV irradiation, so bacteria can still be alive even though more UV fluence is applied. In conclusion, UV LEDs may not be able to disinfect the wastewater to meet the required guidelines for wastewater reclamation unless a proper pretreatment is applied to reduce the turbidity of wastewater to a certain level. |
| Year | 2014 |
| 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) | Visvanathan, C.; |
| Examination Committee(s) | Nguyen, Thi Kim Oanh;Shipin, Oleg V.;Fukushi, Kensuke; |
| Scholarship Donor(s) | China Scholarship Council (CSC); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2014 |