If your system has an alarm panel and a hum you're used to hearing near the tank, you likely have an aerobic treatment unit — and the aerator is the part making that hum.
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A conventional septic tank is an anaerobic system — it relies on bacteria that work without oxygen, breaking waste down slowly as it settles and moves toward a drain field.
An aerobic treatment unit (ATU) works differently. A mechanical aerator — essentially a small air pump or compressor — continuously injects air into the tank. That oxygen supports a different, faster-acting population of aerobic bacteria, which break waste down more thoroughly before it leaves the tank. The result is cleaner effluent than a standard tank produces on its own.
ATUs are common on lots where soil conditions or lot size won't support a standard drain field — a real consideration in parts of St. Tammany Parish with clay-heavy or high-water-table soil.
A conventional tank has almost no moving parts. An ATU has a motor running continuously, which means it's a mechanical component with a service life — not something you can simply forget about the way you might a standard tank between pumpings.
Louisiana law generally requires ATU systems to be maintained under a service contract with an LDH-licensed maintenance provider, with periodic inspection visits — because the aerobic process depends on the mechanical parts actually working.
Most ATU control panels have an audible or visual alarm that triggers on a malfunction — don't ignore it.
A working aerator has a steady hum. If it's gone quiet, the motor may have failed.
A properly functioning aerobic system shouldn't produce a strong sewage smell — if it does, the aerobic process may have stalled.
Effluent that looks poorly treated where it discharges is a sign the aeration process isn't working as it should.
Pooling water or unusually lush, bright-green grass over the drain field can indicate the system isn't processing waste properly.
If it's been longer than your service contract calls for since the last inspection, that's worth catching up on before a bigger problem develops.
Specific maintenance frequency and licensing requirements for aerobic treatment units are set by the Louisiana Department of Health and can vary by system and permit. Confirm your system's specific maintenance schedule with your service provider or the LDH On-Site Wastewater Program — see our Resources page.
Aerator motors are mechanical components with a limited service life, and how long one lasts varies by brand, usage, and how consistently the system has been maintained. Regular professional service visits are the best way to catch a failing unit before it stops working entirely.
No. Aerobic treatment unit maintenance and repair in Louisiana must be performed by a contractor licensed through the LDH On-Site Wastewater Program's Maintenance license category.
No — only aerobic treatment units (ATUs) have one. A conventional gravity-fed septic tank doesn't use mechanical aeration at all. If you're not sure which type you have, the parish's Department of Environmental Services can tell you what's on record for your property — see our Buying/Selling guide for how to ask.