Septic System Effects on Water Quality

Karen BickfordLee County Division of Natural Resources

kbickford@leegov.com

Known Human Health Effects – EPA’s Sewer Reporting Program

EPA correlated reports of human illness to sewage exposure through their Sanitary Sewer Overflow reporting program in the 1990’s

EPA research found that sewer and OSTDS effluent contains :

All diseases associated with sewage exposure are life threatening to children, elderly or generally immuno-compromised persons.

Beach closures and boil water notices are issued by the Department of Health based on these findings.

•Bacteria•Parasites•Intestinal worms•Inhaled molds and fungi•Viruses

•Mild to severe gastroenteritis•Severe dehydration•Cholera•Dysentery•Hepatitis

causing

Related Typical Fecal Coliform Contribution≈1,600,000

cfu≈20,000

cfu

≈2,000 cfu

90%-99% removed

Removal efficiency

dependent on design, soil type

& lot size

Florida’s Fecal Coliform Standard (based on safety for human exposure): 200 cfu/100 mL/mo or 800 cfu/100 mL once.

≈200 cfu to surfac

e

Zone of Potential Failure

Related Typical Nitrogen Contribution≈ 23.4 lbs/h/y

≈15.4 lbs/h/y

10%-40% removed

Florida’s Nitrogen Standard:Set by DEP and/or EPA

≈11.55 lbs/h/y to surface

Zone of Potential Failure

Where’s the “smoking gun”?Florida Keys– “use of septic systems in coastal areas is

difficult due to unsuitable soils and the inability to achieve safe setbacks to water source wells and surface water bodies because of high population density.” Reef and water clarity degradation increased substantially in the

1980s. Studies in the 1980’s showed high quantities of nutrients in test wells

and surface water sample points near septic systems (compared to control test sites).

1995 study using radioisotope dye and bacteriophage seeding test demonstrated that waste water traveled from the toilet to a surface water test point 167 m from the septic system within 11 hours.

2005 study demonstrated septic influence by the presence of human enteric virus present on offshore reefs.

http://soils.ifas.ufl.edu/academics/pdf/Non-Thesis%20Projects/Fall%202011/Higginbotham_William_Tom.pdf

Many communities choosing sewer…Port Saint Lucie – In the 1990’s they noticed massive

seagrass die offs. Studies linked high nutrient and bacterial content in lagoons near septic tanks.

Tampa Bay – In the 1990’s they had massive seagrass die offs, fish kills, algae blooms, etc. They formed a nutrient management consortium and stepped up sewering in higher density neighborhoods.

Wekiva Springs – 2004-2006 studies showed high nutrient content in springs near septic systems. The state mandated septic management programs in all springsheds in Florida.

Many more communities in FL have made similar changes.

Water quality costs big bucks to fix… Combined Lee Co total nitrogen clean-up

obligation=162,849 lbs/yr.

Estimated N removal costs $800/lb/yr

Estimated cost obligation is $130,279,200.

Lee Co’s current surface water projects budget allocation is $21,000,000 per year.

=Ouch!

Questions?