ENHANCED NITRIFICATION IN BIOFILMS BY OPTIMIZED OXYGEN ADDITION
Abstract:Nitrification in a packed bed biofilm reactor (Biofor) for nitrification was strongly correlated to oxygen availability. Experiments controlling biofilm diffusion and external mass-transfer were performed.
In one test the airflow was enriched with oxygen to variable levels without changing the total gasflow, thus eliminating hydraulic effects. The reactor was operated at an empty bed water velocity of 10 m/h. The nitrification rate increased instantaneously from 0.45 to 1.0 kg NH4− N/(m3.d) when the oxygen content increased from 20.9 to 50 % in the gasflow. The nitrification rate was correlated to follow a half order reaction rate with respect to oxygen, indicating that diffusion of oxygen into the biofilm was rate limiting.
In another test the airflow at constant oxygen partial pressure changed from 0 to 2.5 – 3.5 Nm3/hr, during operation at three different empty bed water velocities, 6, 8 and 10 m/h, to investigate hydraulic effects on the nitrification rate. The reaction rate and bulk liquid oxygen concentration increased proportional with airflow. The reaction rate increased with increasing water velocity, indicating lower external mass transfer resistance. At 5 mg/l dissolved oxygen the nitrification rates in the reactor were 0.24, 0.39 and 0.53 kgNH4-N/(m3.d) at water velocity of 6, 8 and 10 m/h respectively.
Document Type: Research Article
Publication date: 2001-01-01
More about this publication?
- Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
- Subscribe to this Title
- Membership Information
- About WEF Proceedings
- WEFTEC Conference Information
- Ingenta Connect is not responsible for the content or availability of external websites