Operator terms · Wastewater
What is aeration in wastewater treatment?
Aeration is adding air, and the oxygen in it, to wastewater so the microorganisms in activated sludge can breathe and break down the waste. Blowers or mechanical mixers supply the oxygen the microbes need. Too little air starves them, so the operator controls aeration to keep the process healthy.
Last reviewed 2026-08-03
Feeding the microbes
The microorganisms that clean wastewater need oxygen to do their work. Aeration keeps enough dissolved oxygen in the tank for them to break down the incoming waste.
How it is supplied
Blowers push air through diffusers, or mechanical aerators churn the surface. Operators adjust it: too little oxygen starves the microbes, too much wastes energy.
Common questions
- Why aerate wastewater?
- To give the treatment microbes the oxygen they need to break down waste.
- What supplies the air?
- Blowers with diffusers, or mechanical surface aerators.
- What if there is too little air?
- The microbes are starved and treatment suffers.