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08:13
A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Operating parameters for high nitrite accumulation during nitrification in a rotating biological nitrifying contactor
Christian Antileo1, Marlene Roeckel, Jörg Lindemann
1Department of Chemical Engineering, Universidad de La Frontera, Casilla 54-D, Temuco, Chile. cantileo@ufro.cl
Summary
This study investigated incomplete nitrification in rotating biological contactors (RBCs). Completely submerged RBCs achieved high nitrite accumulation, suggesting oxygen mass transfer limits nitrification efficiency.
Area of Science:
- Environmental Engineering
- Microbiology
- Biotechnology
Background:
- Nitrification is a key process in wastewater treatment.
- Rotating Biological Contactors (RBCs) are used for biological wastewater treatment.
- Incomplete nitrification can lead to nitrite accumulation, impacting effluent quality.
Purpose of the Study:
- To investigate incomplete nitrification in completely and partially submerged RBCs.
- To determine factors affecting nitrite accumulation in RBC systems.
- To model oxygen mass transfer limitations in submerged RBC biofilms.
Main Methods:
- Experimental study using completely and partially submerged RBCs.
- Varying rotation speeds and aeration conditions.
- Molecular analysis using fluorescence in situ hybridization (FISH).
- Biofilm modeling to predict oxygen profiles.
Main Results:
- Partially submerged RBCs achieved 50-90% nitrite accumulation.
- Completely submerged RBCs achieved up to 96% nitrite accumulation.
- Oxygen mass transfer was identified as a rate-limiting factor in submerged RBCs.
- Biofilm modeling predicted limited oxygen penetration (<30 microm).
- FISH analysis showed nitrite-oxidizers located superficially (<200 microm) and ammonia-oxidizers deeper (up to 800 microm).
Conclusions:
- High nitrite accumulation in submerged RBCs is linked to oxygen mass transfer limitations.
- Limited oxygen penetration restricts nitrite-oxidizer growth within the biofilm.
- Biofilm structure and oxygen availability are critical for efficient nitrification in RBCs.
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