파일롯 플랜트 운전을 통한 고도정수처리공정의 최적화

Abstract

The unpleasant taste and odor in the tap water cause various problems for both citizens and water supplier. These days, taste and odor problems are often reported in some water purification plants. Geosmin and 2-MID are known as the major taste and odor causing materials in water purification plants. There are many ways to remove these materials such as advanced oxidation process, activated carbon adsorption and its combination process. In order to apply such a process to water purification plants, pilot plant experiments must be carried out first. Dongbok-Ho is one of the water source of Gwangju city and has a possibility of taste and odor causing potential. Gwangju city plans to retrofit the conventional water purification system into a advanced water purification system in order to prepare for such taste and odor problems. Ozone alone process, Ozone and hydrogen peroxide combination process, activated carbon adsorption process are considered as advanced water purification process. Pilot scale experiments were carried out to find the appropriate processes and to obtain the design and operation parameters. Ozone alone could remove 50% of geosmin. On the other hand, the combination of ozone and 3mg/L of hydrogen peroxide could remove 90% of geosmin and 90% of 2-MIB, simultaneously. Residual ozone is harmful to citizens. Therefore, ozone quenching step is necessary after ozone oxidation process. Considering residual ozone and oxidation efficiency, the optimal ozone dosage is obtained as 0.3 to 2.0mg/L with the 15 minutes of contact time as the result of the experiments. Manganese also threatened water quality. Very often, manganese concentration of the source water exceed 0.05mg/L but it reduced less than 0.0lmg/L by the conventional rapid sand filtration. However, 0.3mg/L of ozone could remove 60% more manganese. Biological activated carbon(BAC) adsorption increased the removal rate of both turbidity and dissolved organic Carbon(DOC).