Assessment of factors influencing the performance of electrochemical disinfection in treating liquid effluent from on-site sanitation systems | |
| Author | Sitichok Tepin |
| Call Number | AIT Thesis no.EV-17-24 |
| Subject(s) | Electrochemical analysis Sanitation--Thailand 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-17-24 |
| Abstract | This work assesses the disturbing factors, from both onsite-sanitation system (OSS) effluent characteristic and hydraulic characteristic, on electrochemical disinfection using Ti/IrO₂. Laboratory batch and pilot scale electrochemical disinfection (ED) experiment was conducted to investigate the primary disinfectant species generation, E. coli inactivation performance with different OSS physicochemical and hydraulic characteristic conditions. In addition, Pearson correlation test, response surface methodology based on Box-Behnken design experiment was applied to develop the two statistical models for prediction oxidant demand and optimization of ED in OSS effluent, respectively. The results showed that reactive chlorine species (RCS) (e.g., free chlorine and chloramines) was generated from electrochemical treatment using Ti/IrO₂ and the concentration of RCS was the main responding to inactivation of E. coli in ED process. The presence of oxidant demand in OSS lead to intensely decreases in disinfection performance, the main contributions of oxidation demand in the OSS were sulfide, and organic matter (aromatic organics, amines) which shown the high correlation (p> 0.95, and 0.80). For the continuous ED system, calcareous deposit from calcium and magnesium will gradually precipitate on the cathode lead to decrease in current efficiency, hence, quite lower disinfection performance was observed after continuously electrolysis more than 20 hour. Moreover, the results of RTD functions shown that higher disinfection performance can be achieved in the plug flow condition with small short-circuit effect. Analysis of the models was shown a high coefficient of determination value in both model for predict necessary disinfection time and energy consumption (0.9482, and 0.7180). 3-Dresponse surface and desirability function have been applied to evaluate the best point of necessary disinfection time with lowest energy consumption for disinfection in different concentration of oxidant demand in OSS. The result shown that when oxidant demand increase 1%, the energy consumption was increase 1.07%, respectively. The result also shown that the using lower the applied current intensity, leading to reduce the energy consumption to achieved the same E. coli log reduction. Hence, ED using Ti/IrO₂ are suitable for treating OSS effluent with oxidant demand lower than 7 mg Cl2L-1, COD, or sulfide lower than 360 mg L-1and 3.5 mg S2L-1, respectively. |
| 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 (EV) |
| Chairperson(s) | Thammarat Koottatep; |
| Examination Committee(s) | Nguyen, Thi Kim Oanh;Chongrak Polprasert; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2017 |