| Title |
Estimating Disinfection Processes in Water Treatment Plants |
| Authors |
윤제용(Je Yong Yoon), 변석종(Seok Jong Byun), 이상덕(Sang Deok Lee), 석관수(Kwan Su Seok) |
| Abstract |
Disinfection process in water treatment plants is one of the most important step in order to inactivate waterborne disease. However, what is the necessary disinfection which has to be achieved in water plants was not properly established in Korea. In this study, we introduced the concept of CT values and evaluated CT in several water treatment plants to propose reasonable guidelines of necessary disinfection capabilities. The concept of CT was referred to the SWTR(Surface Water Treatment Rule) which is current US-EPA regulation. The necessary disinfection capability is expressed by CT which may be variable depending on the type of disinfectant, temperature, and pH etc. C is the concentration of disinfectant in the effluent of clearwell and T(=T-10) is the detention time at which 90% of the water passing through the unit is retained within the basin. Total of 8 water treatment plants(CJ, SS, BS, KG, BW, YC, KC, YJ) were intended to investigate the necessary disinfection capability in clearwell. For two of them, tracer study to find out T_(10) was not possible due to the unavailability of the port of chemical addition in the clearwell. It was found that T-10/T were varied widely from 0.2 to 0.5 even though all the clearwell in water treatment plants investigated were not baffled. For reference, T_(10)/T of 0.1 were given for unbaffled clearwell in terms of US-EPA recommendation. Considering the operation condition of plants and water quality characteristics at the time of study, 6 of water treatment plants successfully met the necessary disinfection capability based on 90% giardia removal. However, under the scenario of worst case which can be anticipated year round, nearly all the water treatment plants failed to meet CT requirements. Therefore, the necessities for adjusting disinfection process to the condition of various water quality were raised. |