Denitrification at low temperatures using a suspended carrier biofilm process

The denitrification process was studied in a stirred lab-scale suspended carrier biofilm reactor at low temperatures (3-20degreesC). The reactor was filled to 50% with Kaldnes K1 carriers. The denitrification rate showed only a rather weak dependence on the temperature, the rate at 3degreesC being approximately 55% of that at 15degreesC. The maximum denitrification rate obtained at 15degreesC was 2.7 g NOx- -Nm(-2) carrier d(-1). The maximum denitrification rate at 3degreesC during an 8-day period was found to be constant. During the 8 days, the hydraulic retention time was approximately 1.5 h and the inlet NO3--N concentration was 30mgl(-1). (C) 2003 Elsevier Science Ltd. All rights reserved.