County Considering Advanced Septic Tanks

During 2011, the county commission will be taking another look at requiring more advanced septic tanks for southern Leon County.  In my view, the proposal before the county commission to require performance based treatment systems (PBTS) probably is not what we need and it is certainly not what the property owners want.  A performance based treatment systems is simply a septic tank with more advanced treatment capability than a traditional septic tank, with some very big differences:  They cost substantially more to install and operate than traditional systems.

The reason for the proposal is to protect groundwater quality of the Floridan Aquifer, which is principal source of drinking water, and Wakulla Springs.  There is evidence that the quality of both have diminished over the past 30 years or so.  However, traditional septic tanks are not the principal source degradation from nutrients such as nitrogen, a byproduct of waste water treatment.  High nitrate levels have more to do with the presence of the city’s waste water treatment facilities than with septic tanks.

Prior to 1980, before the city built the southeast spray field, nitrate levels in Wakulla Springs were less than 0.2 milligrams per liter (mg/l).  Within a decade after opening the drain field, nitrate levels rose to an astonishing 1.5 mg/l.  However, with more environmental awareness, sensitivity, and policies, by the end of the 20^th century, nitrate levels had dropped to around 0.58 to 0.60 mg/l and, for the past decade or so, have been holding around 0.5 mg/l.  The state and others believe that the nitrogen level is still too high and would like to reduce it to less than 0.35 mg/l.

Although the number of traditional septic tanks has increased significantly over the past 30 years, nitrate levels have actually gone down.  Clearly, something unrelated to septic tanks is involved here.  Contributing to reduced nitrogen and nutrient levels have been improved air quality, better control of runoff, more judicious use of phosphates, reduced grazing, and not the least of which, changes in the way the city treats and disposes of waste water.

Nevertheless, both the city and the county are taking steps to reduce their nitrogen footprint.

Currently, the city is spending about $227-million to develop advanced wastewater treatment.  According to the city of Tallahassee, advanced water treatment can reduce nitrogen loading by 75%.  If that is true, I estimate that the city’s efforts could reduce overall nitrogen loading in the county by about 26%

Leon County has responded, in part, by creating the Primary Springs Protection Zone.  The county is also considering a proposal to require performance based treatment systems inside the zone.  Under the most recent version of the proposal, non-homesteaded property owners and homesteaded property owners exceeding a specified household income and property value would be required to use advanced septic tanks for new development, redevelopment, or whenever their traditional septic tank fails.

Given the expected life of traditional septic tanks, it could take another 20 to 30 years to phase in the more advanced systems, which in turn could last another 30 to 40 years.  Together, that means we could be using septic tanks as the primary means of treating southern Leon County’s waste water for the next 50 to 70 years or so.

Do we want to spend the better part of the next century using septic tanks (traditional or advanced) to collect, treat, and dispose of wastewater in southern Leon County?  My feeling is that we probably do not, nor should we.  While I am not convinced that we need to do anything about septic tanks at this time, in the long run, I am prepared to do something.

So what is a better alternative than performance based treatment systems?  If we are going to spend the next 20 or 30 years doing something, we ought to be planning for central sewer in those areas in southern Leon County where there is sufficient density.  While central sewer has its own issues, the advance water treatment efforts currently underway in the city’s system should promote more effective nitrogen reduction than advanced septic tanks.

There are only two such areas in southern Leon County where central sewer may be more feasible than advanced septic tanks: Lake Munson and Woodville.  Of the two, Lake Munson is probably the better candidate for more immediate sewer and, within the next 30 years, Woodville.

In the meantime, if the county is going to insist upon performance based treatment systems for southern Leon County, we also probably need to consider a couple other actions.  First, the county should not permit any other developments inside the Primary Springs Protection Zone unless it provides for central sewer.  Second, we should have a building moratorium outside the Primary Springs Protection Zone until there are sufficient waste water treatment facilities in north and central Leon County to collect, treat, and dispose of sewage without sending it into southern Leon County.

If water quality in the Floridan Aquifer is everyone’s responsibility, the cost of protecting it should not be placed only on those who live in the southern Leon County.  If the county expects neighborhood specific solutions, it should involve those neighborhoods that are making a bigger contribution to the problem: neighborhoods outside the Primary Springs Protection Zone that have sewer.