"Oxygen and Utilization"
By: Mike Baumgartner, ARWA Wastewater Technician
Dissolved oxygen or D.O. is a term we use in the wastewater business quite often. It is one of the big three parameters we control in order to have a successful process. The other two are control of organics (food) and population of microorganisms. Let’s discuss D.O. and how it is utilized.
It is a measure of the amount of free oxygen present in wastewater or mixed liquor expressed in mg/l. Remember, mg/l is the same unit as ppm. Because the treatment process is considered an aerobic condition, our goal is to maintain a metabolic process that produces energy for growth and reproduction. It is important to recognize that after the microorganisms consume their demand for oxygen there is a residual left over. That is the number you read on the meter. It can be expressed as: Supply – Demand = Residual.
Why is this important? We all have read that the D.O. in an aeration basin should run from 1.0 to 3.0 mg/l. Let me suggest to you that anything over that is a WASTE of energy and money. You will get no more benefit. The 1.0 to 3.0 mg/l should be maintained because it is the “bugs” driving force in performance. If you are having issues nitrifying and the ammonia levels are rising – it is most likely a D.O. problem. Remember, nitrifying bacteria need oxygen to work so feed them the driving force – D.O.
First appeared in Waterline, Spring 2015
- More News -
Start Planning Now!
Save the Dates!
ARWA's 45th Annual Technical Training Conference
See you in
March 19-22, 2023
Registration is Open!
Joint Technical Training Conference
Thanks to Everyone
See you next year in Orange Beach!
May 23 - 25, 2023
Hotel Room Block is Open!
Open for Registration
Operator Certification Classes
WW I-II | July 17th, 2023
Water I-II | July 18th, 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