Page 9 - Simplified Wastewater Treatment Fundamentals_Advanced Nitrification P2
P. 9
Advanced Nitrification
Nitrification Seasonal Transitions
Most wastewater facilities endure at least 2 seasons. Northern facilities need to
proactively prepare for all 4 seasons.
It has been previously discussed that Nitrifiers are slow growers, even during the warm
summer months. Autotrophs are cold blooded meaning as temperatures drop, so does
metabolism, or rate of work cells can perform.
Nitrifiers become increasingly inhibited as temperatures approach 12 C. Colder
wastewater temperatures would require extremely long contact times under aeration,
as well as high SRT (older biomass). At 8 C additional time and age cannot keep
Nitrosomonas and Nitrobacter healthy.
As temperatures fall, the slowest growing Nitrobacter will be the first community to
suffer. The evidence can be clearly seen as Nitrite (NO2) levels begin to rise.
