Performance of UV LED and LP UV disinfection systems on bacteriophage MS2 inactivation for domestic wastewater | |
| Author | Poonyanooch Suwan |
| Call Number | AIT Thesis no.EV-16-15 |
| Subject(s) | Bacteriophages 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-16-15 |
| Abstract | Domestic wastewater still contains enteric pathogens, which increase the risk of public exposure to diseases. One of the common advanced disinfection treatments is ultraviolet (UV) disinfection. UV disinfection with conventional lamps has been applied for water and wastewater treatments for pathogen disinfection. UV LEDs are a new favorable alternative kind of the UV disinfection which preferred good resolutions for domestic wastewater after physical pretreatment. The main objective of the study was to compare disinfection efficacies of 2 types of UV disinfection systems (polychromatic UVC LEDs and a monochromatic LP UVC lamp) on the inactivation of MS2 coliphage in domestic wastewater (AIT wastewater) after pretreatment by a membrane filtration system. UV peak wavelengths applied in this study and measured by spectroradiometer were 277.26 nm, and 253.79 nm for UV LEDs and a UVC lamp, respectively. Two batch reactors as the collimated beam apparatuses for each type of the UV source were applied for this study. The irradiance was measured with a spectroradiometer and chemical actinometry (with iodide-iodate actinometer). The incident irradiances of UVC LEDs and LP UVC lamp for the batch reactors by spectroradiometer were 2.980 nm and 24.598 W/m², respectively. The average irradiances of UVC LEDs at 277.26 nm and LP UVC lamp at 253.79 nm by spectroradiometer after applying the collimated beam factors were 2.118 and 19.830 W/m², respectively. Due to the sensitivity of chemical actinometry, the average irradiances obtained from using radiometer measurement with the collimated beam factors were applied in this study. By applying the Chick-Watson model, UV dose response per one-log inactivation of MS2 were 32.137 mJ/cm² for polychromatic source of the 277 nm UVC LEDs and 20.252 mJ/cm² for monochromatic source of the LP UVC lamp. The inactivation rate constants of the UVC LEDs at 277.26 nm and the UVC LP lamp at 253.79 nm for the flow-through reactors were 0.031117 and 0.049377 cm²/mJ, respectively. Two flow-through reactors were constructed for disinfecting permeable effluent wastewater from the woven fiber microfiltration submerged membrane bioreactor (WF-MSBR) with MS2 spiking. In the UVC LED flow-through reactor, four units of 16W UVC LEDs were mounted on 4 sides of a quartz sleeve, emitting inward. For the LP UVC flow-through reactor, a 20W LP UVC lamp was installed inside a stainless steel casing. The flow-through reactors were validated with coffee solutions at varying UV transmittance, UVT (%). The minimum UVT at 277.26 nm was 34.0% for the UVC LED flow-through reactor and the minimum UVT at 253.79 nm was 37.8% for the LP UVC flow-through reactor. The LP UVC flow-through reactor had higher efficiency than the UVC LED flow-through reactor. For the UVC LED flow-through reactor, at an operational flow rate of 10 mL/min, the applied UV dose was 88.4 to 110.1 mJ/cm², resulting in a 2.8-to 3.48-log inactivation of MS2 for the minimum UVT of wastewater. For the LP UVC flow-through reactor, at a flow rate of 1,500 mL/min, the UV dose was higher than 137.97 mJ/cm², and over 7-log inactivation of MS2 was achieved for the minimum UVT of the wastewater. |
| Year | 2016 |
| 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) | Thammarat Koottatep; |
| Examination Committee(s) | Visvanathan, C. ;Beck, Sara E.; |
| Scholarship Donor(s) | Royal Thai Government;Asian Institute of Technology Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2016 |