A plant's nitrification is crucial for the removal of nitrogen and consequently, for the compliance with limit values. Imbalances of the nitrification process are therfore particularly problematic.



The bacteria responsible

Conversion of nitrogenous compounds to nitrate is a process essential for minimizing the concentration of nitrogenous compounds in the receiving waters. The group of nitrifying bacteria are responsible for this conversion and are divided into ammonia oxidizing bacteria and nitrite oxidizing bacteria.

Nitrifying bacteria

Nitrifying bacteria are comprised of the groups of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). They belong to the group of chemolithotrophic bacteria and can, if present, either oxidize ammonia to nitrite or oxidize nitrite to nitrate.

Ammonia oxidizing bacteria

Ammonia oxidizing bacteria oxidize ammonia to nitrite. Typically, they are closely associated with nitrite oxidizing bacteria.

Nitrite oxidizing bacteria

Nitrit oxidizing bacteria oxidize nitrite to nitrate. They have differing tolerance limits for nitrite, i.e. at a certain nitrite level, they are inhibited. Oxidation of nitrite produces nitrate, which is subsequently reduced to nitrogen by denitrifying bacteria.

Observe changes in nitrifying bacteria, act timely

Detection of nitrifying bacteria directly in the process enables to notice population shifts, before effluent limit values are exceeded. Consequently, process changes can be introduced in a timely manner.

Nitrification, effluent limit values

Detecting nitrifying bacteria with VIT®

With VIT® gene probe technology, nitrifying bacteria can be detected directly in the wastewater sample. AOB and NOB are reported individually. Visualization enables an additional evaluation of their activity.

Detection with Nitri-VIT®
Phase contrast image

Phase contrast image

Microscopic image of activated sludge.

After analysis with VIT®: Ammonia oxidizing bacteria shine red, nitrite oxidizing bacteria shine green

VIT® detection

Identical view of the microscopic image and detection by VIT®. Ammonia oxidizing bacteria (red) can be clearly distiguished from nitrite oxidizing bacteria (green).