A fixed biofilm reactor system composed of anaerobic, anoxic(1), anoxic(2), aerobic(1) and aerobic(2) reactor was packed with synthetic activated ceramic (SAC) media and adopted to reduce the inhibition effect of low temperature on nitrification activities. The changes of nitrification activity at different wastewater temperature were investigated through the evaluation of temperature coefficient, volatile attached solid (VAS), specific nitrification rate and alkalinity consumption. Operating temperature was varied from 20 to 5 ℃. In this biofilm system, the specific nitrification rates of 15 ℃, 10 ℃ and 5 ℃ were 0.972, 0.859 and 0.613 when the specific nitrification rate of 20 ℃ was assumed to 1.00. Moreover the nitrification activity was also observed at 5 ℃ which is lower temperature than the critical temperature condition for the microorganism of activated sludge system. The specific amount of volatile attached solid (VAS) on media was maintained the range of 13.6-12.5 mg VAS/g media at 20~10 ℃. As the temperature was downed to 5 ℃, VAS was rapidly decreased to 10.9 mg VAS/g media and effluent suspended solids was increased from 3.2 mg/L to 12.0 mg/L due to the detachment of microorganism from SAC media. And alkalinity consumption was lower than theoretical value with 5.23 mg as CaCO3/mg NH4 +-N removal at 20 ℃. Temperature coefficient (θ) of nitrification rate (20 ℃ ~ 5 ℃) was 1.033. Therefore, this fixed film nitrogen removal process showed superior stability for low temperature condition than conventional suspended growth process.

Abstract
 1. Introduction
 2. Materials and Methods
  2.1. Experimental setup
  2.2. Characteristics of fabricated ion selectivemicroelectrode
 3. Results and Discussion
  3.1. Specific nitrification rate at different temperature
  3.2. Variation of ammonia and nitrate ion microelectrodecalibration curves according to elapsed time
  3.3. Alkalinity consumption in the nitrification
  34.6 days as the wastewater temperature had beendowned from 20 ℃ to 5 ℃, VAS was not severely changed.
 4. Conclusions
 References

• Se-Yong Jang(Facility Devision, Pusan National University)
• Im-Gyu Byun(Institute for Environmental Technology and Industry, Pusan National University) Corresponding author