In this study, the two-stage electroflotation-rising process was investigated with the aim of improving the performance of the conventional one-stage electroflotation process. A total of 32 min (the electroflotation and rising times were 30 min and 2 min, respectively,) was required when a current of 0.35 A was applied in the one-stage electroflotation-rising experiment. The amount of electric power required to treat 1 m3 of water was 1.75 kWh/m3. For the two- stage system, the time required to achieve a turbidity removal rate of over 95% was 16 min (50% of the one-stage system). The amount of electric power required to treat 1 m3 of water was 0.59 kWh/m3, which was only 33.7% of that required for the one-stage process. The total treatment time and electric power were excellent in case of the two-stage system in comparison with those of the one-stage process. The rate of turbidity removal for the horizontal electrode arrangement is 9.3% higher than that of vertical electrode arrangement. When Na2SO4 was used as the electrolyte, the optimum electrolyte concentration was 1.0 g/L.

Abstract
1. 서 론
2. 재료 및 방법
    2.1. 반응기와 실험방법
    2.2. 분석 및 측정방법
3. 결과 및 고찰
    3.1. 1단계 전기부상-상승 공정의 성능 평가
    3.2. 2단계 전기부상-상승 공정의 적용가능성과 성능평가
    3.3. 2단계 전기부상-상승 공정의 성능 평가
    3.4. 2단계 전기부상-상승 성능에 미치는 전극 설치 방향과 전해질 농도의 영향
4. 결 론
REFERENCES

• 김동석(대구가톨릭대학교 환경과학과) | Dong-Seog Kim (Department of Environmental Science, Catholic University of Daegu)
• 박영식(대구대학교 자유전공학부) | Young-Seek Park (Division of of Liberal Studies, Daegu University) Corresponding author