Optimization of electrochemical disinfection technology for the treatment of liquid effluent from onsite sanitation systems | |
| Author | Araya Wicheansan |
| Call Number | AIT Thesis no.EV-15-30 |
| Subject(s) | Electrochemical analysis Disinfection Water--Purification--Disinfection Sanitation--Thailand |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. EV-15-30 |
| Abstract | Currently, electrochemical disinfection system are being widely used to be highly effectiveness in killing of microorganism. However, its application for onsite sanitation system is rare. This research aims to optimize the performance of electrochemical disinfection system for treatment of liquid effluent from onsite sanitation systems and develop the kinetic model to validate in the blackwater. The pathogen inactivation rates were conducted in synthetic wastewater at different operation conditions of voltages (5 V and 12 V), distance between electrodes (1 cm and 2 cm) and electrolyte concentrations (43, 95, and 2000 mg/L) before develop inactivation kinetic model. pH, temperature, conductivity, and current density were observed to evaluated the affecting factor of electrochemical disinfection system. Then, the septic tank effluents were sampling to test in the intermittent experiment to optimize the performance of the electrochemical disinfection system and validation kinetic model with the actual toilet wastewater in the pilot scale. The results found that in case of low chloride concentrations, E.coli can be inactivated 1 log-reduction within an hour under 5 voltages at distance between electrodes of 1 cm with 0.0157 % NaCl and 6 log-reductions within 15 minutes under 12 voltages, exclude at distance between electrode 2 cm with 0% and 0.007% NaCl. On the other hand, if chloride concentration in the wastewater is high, current density is not significant. E.coli can be inactivated rapidly. Ascaris lumbricoides eggs cannot be inactivated by electrochemical disinfection system due to improper pH, in insufficient chlorine compounds in the water and inadequate the suitable temperature for inactivation. The significant factors on the performance of pathogen inactivation include a chloride concentration which is the main effect on pathogen inactivation, voltage (charge loading) and the operation time. On the other hand, distance between electrodes is the factor is not significant on the performance of pathogen inactivation. The optimum operating condition of electrochemical disinfection need the appropriate current density and minimize energy requirement. Weibull model was modified the relationship between current density and E.coli removal before convert in the first-order model to fit on the value of density and E.coli removal with R2. However, Observed data of E.coli log reduction in pilot scale was not fitted on the predicted E.coli log reduction from the model because of disrupting factors such as the scum layer, suspended solid in the wastewater. |
| Year | 2015 |
| 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) | Thammarat Koottatep |
| Examination Committee(s) | Shipin, Oleg V.;Sompong Hirunmasuwan |
| Scholarship Donor(s) | Bill &Melinda Gates Foundation through the Sustainable Decentralized Wastewater Management in Developing Countries Project;Royal Thai Government Fellowship |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2015 |