Aerobic Treatment Unit Homeowner
For Owners/Users of Aerobic Treatment Systems:
Did you know that your household waste is processed
directly onsite by a special kind of septic system called an aerobic
treatment unit (ATU)? ATUs are not only more versatile than a
conventional system but, also more efficient at processing waste.
This highly versatile and efficient system has many advantages
including the ability to be installed in a place where a
conventional systems could not go (due to soil quality or site
conditions), as well as providing the ability to build a larger
house on a smaller lot (ATUs require a smaller drainfield size than
conventional systems). Additionally, ATUs reduce the amount of
biological material that enters your drainfield. This not only
extends the lifespan of your drainfield, but also makes your ATU
more environmentally friendly than a conventional system. ATUs can
even be added to existing systems to help fix malfunctioning
systems. So, go ahead—feel proud to be the owner of an ATU!
Just like the city sewer system, there are fees
associated with using an ATU. These fees are a direct result of the
need to maintain a current operating permit and a maintenance
contract for the life of the system. With these in place, you can
rest assured that your ATU is receiving the maintenance it requires
to function at its peak levels.
The information contained within this packet should
answer most of the questions you have about your ATU. The first
section will define an ATU and explain how it works. The second
section introduces you to the state’s requirements concerning ATUs,
as well as the people who will be helping you to uphold those
requirements. The next section is a quick reference section
containing bulleted lists with crucial information (i.e. state
requirements, homeowner do’s and don’ts, common compliance issues,
suggested items for homeowner records, etc.). The final section
includes information that you will want to keep for your records: a
copy of the original construction permit, a copy of the operating
permit, a copy of the maintenance agreement, a site plan showing the
location of the ATU on your property, information on your specific
ATU, and a maintenance record. It is highly recommended that you
take the time to review this information.
ATU Program Coordinator:
Congratulations! You have an Aerobic Treatment Unit (ATU). ATUs
are similar to conventional septic systems in that they both use
natural processes to treat wastewater from your home.
Conventional septic systems use anaerobic treatment, which is
treatment without the use of oxygen, while aerobic treatment
units use aerobic treatment, which is treatment in the presence
of oxygen. Aerobic treatment units use air, the oxygen source,
to reduce the concentrations of certain pollutants in your
sewage. When compared to conventional septic tanks, ATUs break
down organic matter more efficiently, achieve quicker
decomposition of organics solids, and reduce the concentration
of pathogens in the wastewater.
Richard Tompkins, Environmental Specialist II
2295 Victoria Ave #206
Fort Myers, FL. 33901
How Aerobic Treatment Units Work
ATUs force compressed air through the liquid effluent in the
tank to create a highly oxygenated (aerobic) environment for
bacteria. “Bacteria that thrive in oxygen-rich environments work
to break down and digest the wastewater inside the aerobic
treatment unit ”. Aerobic units come in a variety of sizes and
shapes such as rectangular, conical, and oval. They can be made
of concrete, fiberglass or polyurethane. They are designed to
collect and treat all the water from your home, including water
from toilets, showers, bathtubs, sinks, and laundry. There are
as many as three stages that your ATU takes wastewater through
before the sewage is dispersed into the drainfield.
Some ATUs have a step before the actual aeration begins. This is
pretreatment and it helps to reduce the amount of solids and
other materials that the bacteria cannot degrade that go into
the system. These solids include grease, oil, toilet paper, and
other substances that get put down the drain or flushed into the
system. This stage may take place in a separate tank or in a
compartment of the ATU itself. Typically pretreatment is
optional but it can greatly improve the ATUs performance.
*Aerobic Treatment Unit*
The aeration chamber is where the bacteria decompose the
pollutants in the wastewater. The ATU consists of a pump, pipes,
and diffusers. The pump compresses the air that flows into the
chamber. The pipes carry the air from the aerator to the
diffusers. The diffuser forces air into the water in the form of
bubbles which introduces oxygen into the sewage. There are two
main types of ATUs: suspended growth units and attached growth
units. Suspended units are the most common type of ATU and work
by mixing air with the sewage to feed the free floating bacteria
without the use of any type of medium. In attached growth units
the bacteria is attached to some type of medium located inside
the ATU itself.
The settling chamber is a calm area which allows settling to
occur with the use of gravity. This is the area where the clear,
treated water is separated from the bacteria that have been
treating the sewage and other solids before they leave the
system and travel to the drainfield.
After all the treatment is complete what started as sewage is
now effluent which is discharged into the ground and allowed to
filter through the soil and continue further treatment. The
effluent from aerobic treatment units can be discharged into a
variety of different drainfield systems. There are gravel
systems, chamber systems, pipe systems, and Dripline systems.
All these different materials have different requirements, sizes
and capacities. There are gravity feed systems and pump systems.
The type of drainfield material you have present depends on what
you, the builder or the engineer wanted installed. The health
department is not involved in that decision.
Maintaining a Healthy ATU (it’s a Team Effort!)
The Department of Health (DOH) has outlined a list of
requirements in chapter 64E-6 of the state’s administrative code
that, when properly followed, will ensure the preservation of
the integrity of each ATU installed in Florida. Upholding these
requirements is truly a team endeavor, as it depends upon a
concerted effort on behalf of the maintenance entity, the DOH
ATU coordinator, and YOU—the homeowner.
What are the requirements?
The homeowner is required to maintain a current maintenance
agreement for the life of the system. The maintenance agreement
must initially be good for two years. Subsequent contracts must
be good for at least a one year period. The cost of a
maintenance agreement varies depending on the type of system you
have and the maintenance entity you select or, whether the
operating permit fee is included or billed separately. The
maintenance entity you select is required to inspect/ service
your system at least two times per year and submit service
reports to the health department. The maintenance entity is
responsible for obtaining an operating permit from the health
department for the system. The operating permit must be renewed
with the health department every two years at a cost of $150. In
addition, an environmental specialist employed by the health
department is required to inspect your ATU at least once per
year to verify that it is functioning properly.
Who are the Team Members?
The maintenance entity is an important team member as they have
earned certification to service your specific type of ATU
directly from the manufacturer. Therefore, the maintenance
entity is not only equipped to handle all technical aspects of
maintaining your ATU, but also is a valuable source of
information. Florida administrative code places the following
responsibilities on the maintenance entity: submission of
semi-annual inspection reports to the health department,
obtaining the operating permit and service related issues.
(NOTE: Not all malfunctions are covered under the
warranty/maintenance agreement. See copy of maintenance
agreement in this packet.)
The DOH ATU coordinator is responsible for ensuring that the ATU
remains compliant with Florida administrative code and does not
become a public nuisance. To accomplish this, your DOH ATU
coordinator reviews the inspection reports submitted to the
health department by the maintenance entity for completeness,
keeps detailed records of issues relevant to your ATU, and
performs annual DOH ATU inspections.
The homeowner is the most essential team member as their
lifestyle has a direct effect on the performance of the ATU. The
homeowner can do their part to maintain peak performance of
their ATU by keeping accurate records (i.e. site plan showing
location of system and copies of maintenance contracts,
operating permits, service reports, and correspondence) and
being mindful of how they dispose of their waste (please refer
to list of Do’s and Don’ts contained within the quick reference
section of this packet).
Common Compliance Issues:
- The maintenance entity must maintain a current operating permit
for the life of the system. The operating permit must be renewed
every two years. Payment of $150.00 to the Lee County Health
Department will be due.
- The homeowner must maintain a current maintenance contract with
an approved maintenance entity for the life of the system. The
maintenance contract should initially be good for two years.
Subsequent renewals must be good for at least a one-year term
for the life of the system. Prices vary depending on maintenance
entity selected and type of system.
- Maintenance entity is required to inspect/service the ATU at
least two times per year. Inspection reports must be submitted
to the Lee County Health Department.
- The health department must inspect the maintenance, and
performance, of the ATU at least once per year.
Signs your ATU may not be functioning properly
- No current maintenance contract on file
- No current operating permit on file
- Evidence of overflow
- Alarm not functioning properly
- Blower/aerator not functioning properly
- Hole/crack in lid and /or lid not secured
- Unit not readily accessible
- Bypass on system
Suggestions for Homeowner Records:
- Alarms or lights going off
- Changes in the system’s normal operating sound
- Plumbing backups
- Sewage odors in the house or yard
- Sewage on the ground
Homeowner Do’s and Don’ts
- Copy of site plan showing location of ATU
- Copy of all operating permits issued
- Copy of all maintenance contracts
- Copy of service reports
- Copy of any correspondence between maintenance entity and/or DOH
ATU program coordinator
- Copy of original permit
- Keep the system accessible for inspection and pumping yet
protected from unauthorized entrance
- Keep electricity going to the ATU at all times
- Call a service professional whenever you experience problems
with your system, whenever the alarm is activated, or whenever
there are any signs of system failure.
- Conserve water to avoid over loading the system. Be sure to
repair any leaky faucets or toilets
- Space out loads of laundry over the week—too much water at once
can hinder system performance
- Divert other sources of water, like roof drains, house footing
drains, and sump pumps away from the system
- Slowly add water back into system when arriving home from
vacation. Too much water entering system after an extended leave
can wash the bacteria in the system out.
- Limit the amount of fat, grease, and food that enters the
system—overloading system with organic material can cause
premature failure. Garbage disposals are NOT recommended for
houses on septic systems.
- Become familiar with how you own particular system operates, and
the way it looks, sounds and smells when it is working correctly
- Keep detailed records on your system (suggestions below)
DO NOT FLUSH LIST…
- Don’t drive or park a vehicle over any part of your system
- Don’t use your toilet as a trash can
- Don’t poison your treatment system and the ground water by
pouring harmful chemicals down the drain
- Don’t make or allow unauthorized repairs to the system. A
permit for repair must be obtained from the county health
- Don’t attempt to clean or perform maintenance on any sealed
aerobic unit components
- Don’t plant trees on or within 4’ of the drainfield.
||Fat, grease or oil
|Original Permit # __________________ Operating Permit
Septic System Installer
Telephone # ___________________
Telephone # ____________________
Trash Tank Size (gallons) ____________________________
ATU Tank Size (gallons) _____________________________
Pump Tank Size (gallons) ____________________________
Drainfield Type ____________________________________
Drainfield Dimensions _______________________________
Number of Drainlines ________________________________
Date System Installed ________________________________
System Maintenance Record