A few examples of misplaced blame involving septic systems do exist, but they have not been widely published or acknowledged. There are far more examples of other serious causes of nutrient and bacterial pollution, and by comparison, the water quality impact from septic systems is dwarfed by the impact of these wastewater treatment infrastructure “events.” In summary, there is little scientific evidence that show septic systems are the culprit they are made out to be. Some examples of the existing septic system studies are presented first. Infrastructure failures, second.
Suwannee River Study – 750 septic systems blamed for bacteria and nitrogen pollution were converted to sewer. Follow-up study found no reduction in either. Wildlife and fertilizer were found to be the problem.
Indian River Study FDOH, Two year study found waterfowl and domestic chickens responsible for nutrient and bacteria levels.
Indian River Study, Florida Institute of Technology. Field tested 16 code-compliant systems in the lagoon area and found insignificant impact from septic systems. Study funded by St. Johns Water Management District and National Park Service.
South Carolina lowland study – septic systems blamed for oyster bed decline. Independent study found overpopulation of raccoons was causing the nutrient pollution. Relocation of excess raccoon population solved the problem.
FDOH 2007 Assessment – 6% nitrogen input from septic systems, 94% other sources. In spite of this assessment, agencies, county governments and legislation has proposed, and is currently spending millions of dollars on septic system conversions to advanced systems or conversion to sewers. Disproportionate focus and cost given the lack of science, and the size and scope of the issue.
Sewer Infrastructure Failures
SEWER INFRASTRUCTURE FAILURES release untreated sewage in great quantities. Untreated sewage is considered hazardous waste by FDEP. Waste pumped from a septic system is considered a biosolid waste as a result of the pre-treatment capability of the tank. These are just a few of the infrastructure failure events recorded just since 2010:
2010 Biscayne Bay, Miami. 2 million gallons of raw sewage dumped from the local municipal plant in a heavy rain event.
2011 Escambia County – 2.2 million gallons of raw effluent dumped into Sandy Creek and Thompson Bayou from a lift station failure
2012 Santa Rosa County – 750,000 gallons of raw effluent dumped into the local bayou from a lift station failure
2013 Altamonte Springs 55,000 gallons per hour of raw effluent leaked into the Little Wekiva River from a ruptured sewer pipe. Event lasted ten days, and pumper trucks intercepting flow had to get a special hazardous waste permit to haul the effluent over public roads to the nearest operational sewer line.
2016 Tampa Bay – The city’s public works administrator told City Council on Thursday September 9th that the city will never know the exact amount of partially-treated sewage that has been dumped into Tampa Bay for the past eight days. Claude Tankersley said a stuck flow meter on discharge pipes made it impossible to determine how many millions of gallons have befouled the bay since Aug. 31. “And the city will never know,” he confirmed to the Tampa Bay Times.
The Tampa Bay Tribune article went on to say that earlier in the week, the city notified the state’s Department of Environmental Protection that more than 20 million gallons of wastewater had been dumped and the amount was increasing. Council members vent their frustrations at the third dump into the bay since August 2015 but there has been no specific actions or recommendations forthcoming. At least 60 million gallons have been spilled or dumped in Tampa Bay since last year due to heavy rains overwhelming their treatment plants.
In addition to the 2015 tally of spills, Hurricane Hermine’s rains have caused another 230 million gallons of untreated sewage to be dumped from treatment plants into the bayous and Gulf. Overflows from manholes backing up sewage into the streets drained into neighborhoods and storm sewers in the Tampa Bay area. The number of total gallons is still growing – details appeared in the Tampa Bay Times, Sept. 15, 2016.
Examples like these above continue with each heavy rain event in Florida.
Exfiltration
Exfiltration is typically not included in the estimates of nitrogen inputs, although exfiltration (leaking sewer pipes) is a daily event. This is a volume of raw waste that never reaches the sewage treatment plant. Exfiltration contributes more waste-related nitrogen than septic systems (estimates are over 20 times – a population-based volume calculation of effluent flowing into sewers versus effluent generated by population served by septic systems. If exfiltration was included, septic system nitrogen contribution would be near zero.
The Environmental Protection Agency estimates 240,000 water-main breaks occur in the U.S. each year. As many as 75,000 yearly sewer overflows discharge up to 10 billion gallons of untreated wastewater, the EPA said on its website. Source: Bloomberg News.
All of this overflow and we have not yet counted the effluent that just leaks from broken sewer pipes. This number is much more complex to calculate since no one knows exactly where the leaks occur. Calculations must be done on a “how much went into the sewer and how much was received by the municipal treatment facility. Source: EPA
The Misuse of the MACTEC Report estimates nitrogen input from human waste sources, which includes sewers and septic systems, without consideration for exfiltration from leaking sewer lines.
Stormwater, Rapid Infiltration Basins, and Injection Wells
During rain events, which are frequent in Florida, these three permitted infrastructures fill our streams, ground water, and aquifer with garbage, fertilizer run-off, chemicals and oil from automobiles, organic materials, dead animals, animal and human waste. By comparison, the nutrients reaching ground water or springs from septic systems is insignificant and the attention paid to septic systems nitrogen contribution is disproportionate to the actual size and scope of the problem.
Governmental Permitted Sources of Pollution
The three permitted sources of nitrogen entering the groundwater are:
- Stormwater
- Rapid Infiltration Basins
- Injection Wells
Stormwater
Urban surface runoff, or stormwater, is contaminated by nonpoint pollutants such as nitrogen, heavy metals and polycyclic aromatic hydrocarbons derived from traffic activity. Surface runoff has been considered an important pathway for delivery of pollutants to water environments. Non-point pollutants are widely distributed in the atmosphere and on surfaces. Since it is difficult to control these distributed pollutants, pollutant loads from nonpoint sources have become relatively larger than those from point sources.
Source: Jianjun Chen, Richard C. Beeson, and Brian Pearson of the University of Florida, IFAS, Mid-Florida Research and Education Center, Apopka, FL 32713.
Further information: on a $500,000 grant to study stormwater can be found in an article published July 11, 2014 in the Apopka Chief entitled, “Apopka IFAS scientists will study effects of read runoff to water.”
Rapid Infiltration Basins
An infiltration basin (also known as a recharge basin or in some areas, a sump), is considered a type of best management practice (BMP) that is used to manage stormwater runoff, prevent flooding and downstream erosion, and improve water quality in an adjacent river, stream, lake or bay. It is essentially a shallow artificial pond that is designed to infiltrate stormwater though permeable soils into the groundwater aquifer. Infiltration basins do not discharge to a surface water body under most storm conditions, but are designed with overflow structures (pipes, weirs, etc.) that operate during flood conditions. It is distinguished from a detention basin, sometimes called a dry pond, which is designed to discharge to a downstream water body (although it may incidentally infiltrate some of its volume to groundwater); and from a retention basin, which is designed to include a permanent pool of water. Source: Wikipedia
Orange County Florida has several such basins. One specifically located in the Northwest corner of the county holds the processed water from the Northwest Orange County Treatment facility. This rapid infiltration basin, by their own admission, introduces into the Wekiva Springs Area 60 metric tons of Total Nitrogen per year.
Injection Wells
An injection well is a vertical pipe in the ground into which water, other liquids, or gases are pumped or allowed to flow. There are, for example, over 400 injection wells in use by Orange County of Florida’s Municipal Treatment facilities.
A principal application is for waste water disposal, in which treated wastewater is injected into the ground between impermeable layers of rocks with the intent to avoid polluting fresh water supplies or adversely affecting quality of receiving waters. Injection wells are usually constructed of solid walled pipe to a deep elevation in order to prevent injectate from mixing with the surrounding environment. Unlike outfalls or other direct disposal techniques, injection wells utilize the earth as a filter to further clean the treated wastewater before it reaches the receiving water. This method of waste water disposal also serves to spread the injectate over a wide area, further decreasing environmental impacts. The St. John’s River Water Management District is the agency that issues permits for Rapid Infiltration Basins, injection wells and treatment plants. Source: Wikipedia
