In this study we followed biofilm formation and development in a granular activated carbon (GAC) filter on pilot-scale during the 12 months of operation. GAC particles and water samples were sampled from four different depths (-5, -25, -50 and –90 cm from surface of GAC bed) and attached biomass were measured with adenosine tri-phosphate (ATP) analysis and heterotrophic plate count (HPC) method. The attached biomass accumulated rapidly on the GAC particles of top layer throughout all levels in the filter during the 160 days (BV 23,000) of operation and maintained a steady-state afterward. During steady-state, biomass (ATP and HPC) concentrations of top layer in the BAC filer were 2.1 μg·ATP/g·GAC and 3.3×108 cells/g·GAC, and 85%, 83% and 99% of the influent total biodegradable dissolved organic carbon (BDOCtotal), BDOCslow and BDOCrapid were removed, respectively. During steady-state process, biomass (ATP and HPC) concentrations of middle layer (-50 cm) and bottom layer (-90 cm) in the BAC filter were increased consistently. Biofilm development (growth rate) proceed highest rate in the top layer of filter (μATP = 0.73 day-1; μHPC = 1,74 day-1) and 78%∼87% slower in the bottom layer (μATP = 0.14 day-1; μHPC = 0.34 day-1). This study shows that the combination of different analytical methods allows detailed quantification of the microbiological activity in drinking water biofilter.

Abstract
 1. 서 론
 2. 실험재료 및 방법
  2.1. 실험재료
  2.2. 실험방법
 3. 결과 및 고찰
  3.1. 운전기간 증가에 따른 용존 유기물질 제거 및 표층부착 박테리아 생체량 변화
 4. 결론
 참고문헌

• 손형식(울산 테크노파크 정책기획단) | Hyeng-Sik Son (Division of Policy Panning, Ulsan Technopark)
• 정철우(울산 테크노파크 정책기획단) | Chul-Woo Jung (Division of Policy Panning, Ulsan Technopark)
• 최영익(동아대학교 환경공학과) | Young-Ik Choi (Dept. of Environmental Engineering, Dong-A University)
• 이건(동아대학교 환경공학과) | Gun Lee (Dept. of Environmental Engineering, Dong-A University)
• 손희종(부산광역시 상수도사업본부 수질연구소) | Hee-Jong Son (Water Quality Institute, Water Authority) Corresponding author