By: Mike Baumgartner, ARWA Wastewater Technician
The oxidation of nitrogen in wastewater treatment is done in three steps. The first step is not talked about much. The process is Ammonification. This is the oxidation of amino acids and urea to Ammonium / Ammonia. The second step is the conversion of Ammonium to Nitrite (No2). Lastly, the process of de-nitrification is the conversion of Nitrate (No3) to Nitrogen Gas and ultimately released to the atmosphere. There are two types of bacteria that are in play. Nitrifying bacteria are called “Nitrosomes” and De-nitrifying bacteria are called “Nitrobacter”.
Two separate conditions must exist for the conversions to take place. The Nitrosomes (Nitrifying) bacteria make up 5% of the overall mass population and only use Ammonia as its food source. They thrive in an oxic condition. The D.O. should be in the 1.5 mg/l range. Nitrobacter bacteria work under anoxic conditions.
Remember, Nitrogen is not removed from the system unless De-nitrification occurs. This step will reduce all forms of nitrogen. It is important to note that since Nitrifying bacteria are few, avoid over wasting or your ammonia may start to rise.
There is one more important topic to discuss since we need a healthy environment for the successful conversion. Not only do we need a healthy influent food source (Carbon and Nutrients), but adequate Alkalinity. Nitrifying bacteria are acid forming so alkalinity is needed to maintain a proper p.H. Remember that 7.2 lbs. of Alkalinity is needed to maintain p.H. per Lb. of Ammonia oxidized.
Test your influent for Alkalinity. Lastly, the Denitrification process will add back around 50% that was lost. That is one of the advantages of that process. In summary, the goal of Nitrification is to oxidize the Ammonia present in the wastewater and De-nitrification will reduce all forms of Nitrogen.
First appeared in Waterline, Summer 2018
- More News -
Start Planning Now!
Save the Dates!
ARWA's 45th Annual Technical Training Conference
See you in
March 19-22, 2023
More info coming soon...
Joint Technical Training Conference
Thanks to Everyone
See you next year in Orange Beach!
May 23 - 25, 2023
Open for Registration
Operator Certification Classes
Water I-II | Feb 21st, 2023
WW I-II | Feb 22nd, 2023
Water III-IV | April 11th, 2023
WW III-IV | April 12th, 2023
See all open CEH classes
in our new training section at
Utility Management Certification
Schedule your own
On-site CEH Training
Water Loss Protection
The ARWA/NRWA ServLine Program protects your utility against losses from customers’ water leaks, and provides the opportunity for them to add service line repair replacement protection.
Pay any ARWA invoice online.
Alabama Rural Water Association is a non-profit organization representing water and wastewater systems serving rural communities and towns and commercial firms which support these systems.
We provide assistance to comply with State and Federal regulations, to help with management and operational problems, and to stimulate training initiatives.
GET IN TOUCHAlabama Rural Water Association
2576 Bell Road
Montgomery AL 36117
Phone: (334) 396-5511
Fax: (334) 396-7090