Drinking water disinfection by electro activated water and its inactivation mechanism on bacteria | Elektro aktif suyun içme suyu dezenfeksiyonunda kullanılması ve bakteri inakvitasyon mekanizmasının belirlenmesi

This thesis aims to produce a cost-effective and safe disinfectant agent which is named electro activated water (EAW). With this purpose, two different reactors were designed to generate EAW and the efficacy of generated water as a disinfectant agent was investigated on bacteria. The operation conditions of EAW system was modelled through Response Surface Methodology. The optimum parameters of disinfection process to achieve an effective inactivation of bacteria was studied. The inactivation efficiency of EAW was evaluated upon measurement of TTC-dehydrogenase activity and flow cyctometry analysis. Furthermore, the inactivation mechanism of EAW on bacteria has been evaluated comparing with sodium hypochloride (NaOCl) and chlorine dioxide (ClO2). The changes of cellular structure for Enterococcus faecalis were presented significantly upon several analyses such as determination of cell membrane integrity, protein leakage, and the measurement of conductivity, determination of DNA damage, SDS-PAGE and FTIR analysis. According to the results, electrolysis time is more important than brine concentration and current for oxidative potential of EAW. On the other hand, chlorine concentration of EAW is the most significant factor during disinfection of bacteria. The inactivation mechanism of NaOCl, ClO2 and EAW was almost similiar, however, EAW destroyed the cell structure considerably, since it inactivated the bacteria in less time with more damage.EAW process was applied for the disinfection of drinking water sample. A cost effective process conditions were determined to obtain complete bacteria removal and provide adequate residual chlorine concentration after 30 minutes of disinfection. Since EAW disinfection process does not cause THM formation, it may be an alternative method for drinking water chlorination. Stability of EAW was tested in different storage conditions.