ATU Septic Systems and
Wakulla Springs



ATU Septic SystemsRecently our community has become aware of a serious threat to the water quality at Wakulla Springs, one of the most beautiful places in the Tallahassee and Wakulla area that has been enjoyed for generations by locals and tourists. Wakulla Springs is one of the world’s largest and deepest freshwater springs. Because of high levels of nitrogen-containing compounds flowing into the Springs we are seeing the explosive growth of an invasive, non-native plant called hydrilla, which has begun to clog the springs and require manual and chemical removal. Too much nitrogen in the form of nitrates acts as a nutrient in rivers and streams, causing the excessive growth of plants and algae. This can cause oxygen depletion which negatively impacts wildlife. Nitrogen is water soluble so wherever water goes, nitrogen goes too.

wakulla-springs-septicPhoto shows the Springs with and without hydrilla infestation :
( V. Ramey 2002 Univ. of Fla.)


Wakulla Springs is located in the Woodville Karst Plain, a unique geologic region that extends south of the City of Tallahassee to the Gulf of Mexico. Here, the limestone aquifer is very shallow. The landscape features numerous sinkholes, springs, open “windows” in the limestone that expose groundwater at the land’s surface and miles of unseen caves and tunnels. Through these “windows” nitrogen from our wastewater flows into the waterways. Wakulla Springs is the largest, single spring in the Woodville Karst Plain. The Wakulla Springs Recharge Area extends from just north of Tram Road in Tallahassee, in an area known as the Cody Scarp, south to Wakulla Springs.


Nitrogen is one of the most abundant elements. About 80 percent of the air we breathe is nitrogen. It is found in the cells of all living things and is a major component of proteins. In the form of nitrates, nitrogen dissolves easily in water and is stable over a wide range of environmental conditions so it is easily transported in streams and groundwater. As our communities have grown, more and more nitrogen-rich wastewater has made its way to Wakulla Springs, mainly from the following sources:

The Tallahassee Wastewater Treatment Plant Sprayfields
Septic systems in the Wakulla Springs Recharge Area
Storm water runoff
Fertilizers and pesticides used on lawns and in agriculture

The protection of Wakulla Springs and mitigation of the current problems will require the cooperation of many entities: government agencies, community groups and homeowners willing to make some changes in how we dispose of wastewater.


There is a common misconception that we can solve our problems with wastewater disposal by eliminating septic systems altogether and converting to centralized sewer. However, the nitrogen does not magically go away when it is transported to a central facility where it must be dealt with in much higher concentrations than what was produced onsite. The Tallahassee Wastewater Treatment Plant Sprayfields has been shown to be a major source of the nitrogen pollution that is harming Wakulla Springs so it should be clear that just sending it all to a central treatment facility does not solve that problem. There are other environmental problems associated with central sewer as well, such as concentrations of heavy metals, chlorine contamination, damage to the environment in the large sewer pipe installation, among others. The cost of centralized sewer is enormous, both in upfront and continuing costs to both the county and the homeowner. Converting everyone to centralized sewer is not a practical or appropriate solution.

The reality is that properly installed, maintained, and located septic systems, using appropriate technology, can be a safe and effective method of disposing of wastewater while protecting both ground and surface water and the community health standards. Some areas, such as the Wakulla Springs Recharge Area, are not suitable for standard septic systems but require advanced treatment or specialized designs now available. The community needs to identify these environmentally sensitive areas and mandate advanced treatment and management standards for them.

Recent innovations in septic system technologies have been proven to reduce nitrogen and improve effluent quality as demonstrated by the December, 2004 Wekiva Basin Onsite Sewage Treatment And Disposal System Study from the Florida Department of Health. The nitrogen levels of the effluent produced by these latest advances is below the levels that have been recorded at the Tallahassee Sprayfields. Using the HOOT system coupled with drip irrigation we can achieve a nitrogen level of 3 mg/L compared with the sprayheads level of 15 mg/L at the Tallahassee Sprayfield.

Both centralized sewer and appropriate use of septic systems have their place in the constellation of how we manage our community’s wastewater. Our challenge is to find every way possible to make them both as safe as possible for our environment.


The City of Tallahassee has been working to reduce the nitrogen coming from the Sprayfields and has made progress. There are currently studies underway to determine what future steps need to be taken.

Homeowners with septic systems in the Recharge Area also need to be on board with helping to restore the health of Wakulla Springs by using new technology that dramatically reduces the nitrogen coming from the septic system. This can be achieved by installing a nitrogen reducing Aerobic Treatment Unit (ATU) for all new construction and by using this technology to replace older systems when they need repair.

Apalachee Backhoe & Septic Tanks, LLC is a certified installer for an ATU system manufactured by HOOT Aerobic Systems, Inc. An operating permit for these systems, issued by the county, includes a requirement for regular inspections and maintenance.


1. Pretreatment tank where influent enters.
2. Aeration chamber where oxygen is pumped into the waste water.
3. Clarifier chamber where the clear, odorless effluent rises.
4. Chlorinator where the clear effluent passes through for disinfection.
5. Holding tank for disinfected effluent ready for discharge.
6. Extremely quiet, efficient aerator and pump.
7. Unique solid-stateHOOTControlCenter monitors and controls the system.
8. Discharge Pump

The HOOT Aerobic Treatment System is a complete five-stage, one piece wastewater treatment system. This system operates like a small municipal treatment plant.

The nitrogen level at the outlet of this tank is around 10 mg/L. In a standard septic system the level at the outflow from the tank is 20-50 mg/L. By coupling the HOOT system with a drip irrigation system we can lower the nitrogen level even more to around 3 mg/L. This is significantly lower than the 15 mg/L of nitrogen currently being discharged from the sprayheads at the Tallahassee Wastewater Treatment Sprayfields.

In a drip irrigation system the wastewater is discharged through a network of half-inch-diameter tubes typically located about 6 inches below the surface. Effluent is applied at a controlled rate through uniformly spaced drip emitters in the vegetation root zone, which minimizes percolation through the subsoil. Evapotranspiration is enhanced as water evaporates from soil and plants, which transfers the nitrogen to the atmosphere rather than to the subsurface water table.

Contact us at or 850-877-2824 for more information about these remarkable septic systems.