Homes here in the Big Bend of Florida are built over a honeycomb of limestone cracks and caves (called karst). These cracks and caves carry water and chemicals from lawns, roads, and septic systems to the groundwater (our drinking water) and to our springs, rivers, and bays. More and more chemicals are getting into our water this way.
Nitrogen is causing the most trouble. Nitrogen is called a nutrient, because it feeds plants and makes them grow. Nitrogen is feeding the growth of water weeds and algae in places like Lake Lafayette, Lke Jackson, Lake Munson and Wakulla Springs. Too much nitrogen in our drinking water can cause health problems, too. Every person in our community needs to know how nutrients (such as nitrogen and phosphorus) are getting into our water – and what we can do to protect our drinking water and our springs, rivers, and bays. We are all part of the problem. We must all be part of the solution.
Where Does Nitrogen Come From?
Nitrogen in our water comes from many places – nitrogen in the air, sewage treatment sprayfields, fertilizers, septic tanks, pet and farm animal wastes, and stormwater runoff.
HOW NITROGEN GETS INTO OUR WATER FROM SEPTIC SYSTEMS
From Beyond Septic Tanks, Tallahassee-Leon County Planning Department, August 2006
Nitrogen Can Come from Septic Tanks
Each septic system can put nitrogen into our water. Some newer kinds, called nitrogen-reducing systems or advanced treatment systems, put a lot less nitrogen into our water. Inside a septic tank, solids sink to the bottom and grease floats to the top of the tank. Then liquid flows out of the tank to the drainfield, carrying nitrogen with it. Some nitrogen is removed by our sandy soil as the liquid from the drainfield travels to the groundwater.
In a nitrogen-reducing system, the liquid in the tank is first mixed with air, and then starved of air. This removes much of the nitrogen in the tank and turns it into harmless gas. Up to 75% of the nitrogen goes into the air (instead of the drainfield). As little as 25% gets into our water.
When Should I Replace my Septic Tank with a Nitrogen-Reducing System?
Some people are installing nitrogen-reducing systems now, because it is the right thing to do to protect our springs, bays, and drinking water. Others will install the new systems when major repairs are needed to their existing septic systems. Still others may wait until county ordinances or state laws require them to upgrade their system or connect to central sanitary sewer systems.
How Much Does a Nitrogen-Reducing System Cost?
The cost of installing any septic system depends on the site; for example, the size of your house, how close you are to water, how much fill dirt is needed, your soil type and other such site conditions. For example, a three-bedroom house, installing a traditional septic system costs from $2,000 to $8,000. Installing a nitrogen-reducing system costs from $8,000 to $15,000. Nitrogen-reducing systems also have small monthly electricity costs. Operating permits and maintenance contracts add to the costs too.
How Do I Get a Nitrogen-Reducing System?
The first step is to contact either a septic system installer or an engineer who works with these systems. You may find it helpful to visit http://www.doh.state.fl.us/ENVIRONMENT/ostds/ to see a list of licensed installers. There, too, you will find general information on septic systems and nitrogen-reducing systems.
How Do I Maintain a Nitrogen-Reducing System?
The installer (or other maintenance company) will check the system 2-4 times yearly. They will get needed permits, also. Like septic tanks, these systems should be pumped (to remove the sludge that builds up in the tank) every 3-5 years.
From Beyond Septic Tanks, Tallahassee-Leon County Planning Department, August 2006