| Author | Nguyen Thi Minh Hong |
| Call Number | AIT Thesis no.EV-17-13 |
| Subject(s) | Sewage--Purification--Disinfection
|
| 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-17-13 |
| Abstract | Pretreatment system including tube settlers sand filter supposed to give an appropriate wastewater quality for UV disinfection flow through reactor. Performance of pretreatment system depended on overflow rate of tube settlers and corresponding filtration rate of sand filter. Corresponding with inlet flowrate of the system including 500, 1000 and 1500 mL/min, the tube settler was operated at 0.016, 0.032 and 0.048 m³/m².h with sand filtration rate at 0.15, 0.3 and 0.45 m³/m².h. The highest performance of pretreatment system was achieved at first operating condition, overflow rate 0.016 m³/m².h with 2.53 hours of HRT of tube settlers, corresponding filtration rate of sand filter is 0.15 m³/m².h. The treatment performance decreased when inlet flowrate increased and there was no statistical significant different in performance of other two remaining flow rates. The MS2 inactivation rate constant achieved in this study was 0.0519 ± 0.0003 cm²/mJ on UV-LEDs laboratory collimated beam batch reactor. UV dose response of MS2 coliphage to the 280 nm LEDs was 19.27 mJ/cm² for 1 log inactivation and 38.5 mJ/cm² for 2 logs inactivation. In UV-LEDs flow through reactor, with the treated wastewater, 3.1 ± 0.1 logs MS2 coliphage reduction was only reached when the operation flow rate is 30 mL/min and the corresponding contact time was 137 seconds. The calculated electrical energy per order of MS2 coliphage reduction of the UV-LEDs reactor was 0.01165 kWh/m³ at operating flow rate of 30 mL/min. In continuous feeding condition with flow rate of 30 mL/min, the disinfection efficiency on MS2 coliphage spiked into distilled water was reduced from 3.7 logs reduction to under 1 log from the pre-fouled condition to after 600 hours of continuous operation. Fouling effect was clearly observed from the 6th operating day by more than 1 log of MS2 coliphage inactivation decreased. Cleaning procedure should be taken after 400 hours continuous operation to avoid further reduction of disinfection efficacy. Summary of mechanisms of fouling effect in this case of study could be sedimentation inorganic and organics Calcium, Magnesium and Iron complexes preformed particles in treated wastewater and precipitation of UV-induced organic complexes of these elements and organic fouling placed the most important role. In optimal cleaning test, the results of log MS2 inactivation indicated that the original performance of UV-LEDs reactor was only achieved after soaking with citric acid solution in 4 hours and beyond. |
| Year | 2017 |
| 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.;Shipin, Oleg V.;Beck, Sara E.; |
| Scholarship Donor(s) | AITCV Silver Anniversary Scholarships; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2017 |