Effects of coagulation types on flocculation were investigated by using a photometric dispersion analyzer (PDA) as an on-line monitoring technique in this study. Nakdong River water were used and alum and ferric chloride were used as coagulants. The aim of this study is to compare the coagulation characteristics of alum and ferric chloride by a photometric dispersion analyzer (PDA). Floc growing rates (Rv) in three different water temperatures (4℃, 16℃ and 30℃) and coagulants doses (0.15 mM, 0.20 mM and 0.25 mM as Al, Fe) were measured. The floc growing rate (Rv) by alum was 1.8∼2.8 times higher than that of ferric chloride during rapid mixing period, however, for 0.15 mM∼0.25 mM coagulant doses the floc growing rate (Rv) by ferric chloride was 1.1∼2.3 times higher than that of alum in the slow mixing period at 16℃ water temperature. Reasonable coagulant doses of alum and ferric chloride for turbidity removal were 0.1 mM (as Al) and 0.2 mM (as Fe), respectively, and the removal efficiency of those coagulant doses showed 94% for alum and 97% for ferric chloride. The appropriate coagulant dose of alum and ferric chloride for removing dissolved organic carbon (DOC) showed about 0.3 mM (as Al, Fe) and at this dosage, DOC removal efficiencies were 36% and 44%, and ferric chloride was superior to the alum for removal of the DOC in water.

Abstract
 1. 서 론
 2. 실험재료 및 방법
  2.1. 낙동강 원수 및 응집제 선정
  2.2. 응집실험
  2.3. 분석방법
 3. 결과 및 고찰
  3.1. 수온별 및 응집제 투입농도별 FSI 평가
  3.2. 탁도 및 용존 유기물질 제거능 평가
 4. 결 론
 참 고 문 헌

• 손희종(부산광역시 상수도사업본부 수질연구소) | Hee-Jong Son (Water Quality Institute, Water authority) Corresponding author
• 염훈식(부산광역시 상수도사업본부 수질연구소) | Hoon-Sik Yoom (Water Quality Institute, Water authority)
• 김상구(부산광역시 상수도사업본부 수질연구소) | Sang-Goo Kim (Water Quality Institute, Water authority)
• 서창동(부산광역시 상수도사업본부 수질연구소) | Chang-Dong Seo (Water Quality Institute, Water authority)
• 황영도(부산광역시 상수도사업본부 수질연구소) | Young-Do Hwang (Water Quality Institute, Water authority)