Septic tanks contribute to nutrient overload in waterways

OKEECHOBEE — A potential source of water pollution could be in your backyard.

Nationwide about 20 percent of American homes use Onsite sewage treatment and disposal systems (OSTDS), more commonly known as septic tanks. In most states, septic tanks are used in rural areas where it is not cost effective to run sewer lines to remote homes. In Florida, according to the Florida Department of Environmental Protection, about 30 percent of all homes have septic tanks. Florida is home to 12 percent of all of the septic tanks in the United States. Unlike northern states where most homes with septic tanks are in rural areas surrounded by farmland, in Florida septic tanks can be found in urban coastal areas where development outpaced sewer line expansion or where developers opted to put in septic tanks to cut costs rather than pay the fees required for sewer line expansion and hookups.

The Florida Department of Environmental Protection (FDEP) estimates there are about 2.6 million homes in Florida with septic tanks. Many of these septic tanks are in environmentally-sensitive watersheds.

While manufacturers recommend septic tanks be pumped out and inspected every 1 to 5 years (the EPA recommends 1 to 3 years), according to FDEP, only about 100,000 septic tanks in Florida are pumped out each year. That means more than 2 million septic tanks have not been pumped out within the past 5 years. According to testimony given in Florida Legislative hearings, many have not been pumped out in 20 years or more.

In 2010, under Governor Charlie Crist, the Florida Legislature passed a law requiring septic tanks be inspected at least once every 5 years. Two years later, the Legislature repealed the law. Two years later, with Rick Scott in the governor’s office, the Florida Legislature repealed the law.

Typical septic tank and drain field. Courtesy of the Environmental Protection Agency.

In rural areas, where residents are more likely to have grown up in a home that had a septic tank, homeowners are more aware of the need for regular septic tank maintenance. Many who move to Florida from an urban area have no experience with septic tanks.

As amazing as it sounds, according to the EPA, some people who buy homes in Florida don’t even know they are not on a public sewer system.

The EPA offers this handy checklist for “how to know your home has an OSTDS.” The EPA website advises:

“You may already know you have a septic system. If you do not know, here are tell-tale signs that you probably do:

“You use well water.

“The waterline coming into your home does not have a meter.

“You show a “$0.00 Sewer Amount Charged” on your water bill or property tax bill.

“Your neighbors have a septic system.”

The EPA advises homeowners protect the OSTDS by conserving water. The average indoor water use in a typical single-family home is nearly 70 gallons per individual, per day. Just a single leaky or running toilet can waste as much as 200 gallons of water per day. All of the water a household sends down its pipes winds up in its septic system. The more water a household conserves, the less water enters the septic system. Efficient water use improves the operation of a septic system and reduces the risk of failure.

“Your septic system is not a trash can,” the EPA advises. “An easy rule of thumb: Do not flush anything besides human waste and toilet paper.”

Never flush:
• Cooking grease or oil;
• Flushable wipes;
• Photographic solutions;
• Feminine hygiene products;
• Condoms;
• Dental floss;
• Diapers;
• Cigarette butts;
• Coffee grounds;
• Cat litter;
• Paper towels;
• Pharmaceuticals;

• Household chemicals like gasoline, oil, pesticides, antifreeze, and paint or paint thinners.

Think at the sink!

A septic system contains a collection of living organisms that digest and treat household waste, the EPA advises. Pouring toxins down the drain can kill these organisms and harm your septic system. Whether you are at the kitchen sink, bathtub, or utility sink, the EPA cautions:

• Avoid chemical drain openers for a clogged drain. Instead, use boiling water or a drain snake.

• Never pour cooking oil or grease down the drain.

• Never pour oil-based paints, solvents, or large volumes of toxic cleaners down the drain. Even latex paint waste should be minimized.

• Eliminate or limit the use of a garbage disposal. This will significantly reduce the amount of fats, grease, and solids that enter your septic tank and ultimately clog its drainfield.
Septic tank/algae bloom connection

In South Florida, phosphorus and nitrogen from septic tanks can contribute to algae blooms in area waterways.

In a Nov, 8, 2017 press conference hosted by the Florida Chamber of Commerce in Tallahassee, Dr. Brian Lapointe of Harbor Branch Oceanic Institute and Florida Atlantic University, pointed to his decades of research which points to leaking septic tanks as a major cause of pollution into the coastal waterways.

“In the research I have conducted on behalf of Harbor Branch Oceanographic Institute in Fort Pierce, the science points directly to human pollution as the number one cause of what’s imperiling our state’s local water sources,” said Dr. Lapointe. “A leading cause of this pollution are aging septic tanks, which are leaking into the Indian River Lagoon and St. Lucie Estuary.”

While the FAU study pointed to the pollution from septic tanks near coastal waterways, this is an issue for rural counties as well.

In Okeechobee County, Taylor Creek/Nubbin Slough is historically high in nutrient load, contributing 21 percent of the total phosphorus load into the lake while just 7 percent of the water inflow. From 2013-2017, Taylor Creek/Nubbin Slough averaged an annual total phosphorus load of 104 metric tons, according to the South Florida Water Management District data. According to information provided at an October Okeechobee County Commission meeting, removal of the Treasure Island/Taylor Creek area septic tanks could reduce the annual nutrient load into the lake by 27.5 tons of phosphorus a year. The county commission has (so far unsuccessfully) sought state help for a septic-to-sewer conversion project for the homes on that waterway.


Know the signs of septic tank failure

Septic systems are underground wastewater treatment structures, commonly used in rural areas without centralized sewer systems. They use a combination of nature and proven technology to treat wastewater from household plumbing produced by bathrooms, kitchen drains, and laundry.

A typical septic system consists of a septic tank and a drainfield, or soil absorption field.
The septic tank digests organic matter and separates floatable matter (e.g., oils and grease) and solids from the wastewater. Soil-based systems discharge the liquid (known as effluent) from the septic tank into a series of perforated pipes buried in a leach field, chambers, or other special units designed to slowly release the effluent into the soil.

Alternative systems use pumps or gravity to help septic tank effluent trickle through sand, organic matter (e.g., peat and sawdust), constructed wetlands, or other media to remove or neutralize pollutants like disease-causing pathogens, nitrogen, phosphorus, and other contaminants. Some alternative systems are designed to evaporate wastewater or disinfect it before it is discharged to the soil.

Specifically, this is how a typical conventional septic system works:

• All water runs out of your house from one main drainage pipe into a septic tank.

• The septic tank is a buried, water-tight container usually made of concrete, fiberglass, or polyethylene. Its job is to hold the wastewater long enough to allow solids to settle down to the bottom forming sludge, while the oil and grease floats to the top as scum.

• Compartments and a T-shaped outlet prevent the sludge and scum from leaving the tank and traveling into the drainfield area.

• The liquid wastewater (effluent) then exits the tank into the drainfield. The drainfield is a shallow, covered, excavation made in unsaturated soil. Pretreated wastewater is discharged through piping onto porous surfaces that allow wastewater to filter though the soil. The soil accepts, treats, and disperses wastewater as it percolates through the soil, ultimately discharging to groundwater.

If the drainfield is overloaded with too much liquid, it can flood, causing sewage to flow to the ground surface or create backups in toilets and sinks.

• Finally, the wastewater percolates into the soil, naturally removing harmful coliform bacteria, viruses and nutrients. Coliform bacteria is a group of bacteria predominantly inhabiting the intestines of humans or other warm-blooded animals. It is an indicator of human fecal contamination.

Failure symptoms: Mind the signs!

A foul odor is not always the first sign of a malfunctioning septic system. Call a septic professional if you notice any of the following:
• Wastewater backing up into household drains.
• Bright green, spongy grass on the drainfield, especially during dry weather.
• Pooling water or muddy soil around your septic system or in your basement.
• A strong odor around the septic tank and drainfield.

If your septic system is not properly maintained, you may be risking your family’s health, hurting the environment, and flushing thousands of dollars down the drain, according to the EPA. In the long run, properly maintaining a septic system is much less expensive than replacing a failed system.

The EPA advises: “Some makers of septic tank additives claim that their products break down the sludge in septic tanks so the tanks never need to be pumped. Not everyone agrees on the effectiveness of additives. In fact, septic tanks already contain the microbes they need for effective treatment. Periodic pumping is a much better way to ensure that septic systems work properly and provide many years of service. Regardless, every septic tank requires periodic pumping.”


Septic system maintenance important

Septic tank maintenance is like changing the oil in your car, you don’t want to wait until there is a problem, said Ashley Austin-Neehan of Austin Sewer and Septic in Okeechobee.

Onsite septic systems do work, she said, “There is science behind them. But they have to be maintained.”

Septic tanks should be pumped out regularly, every 1 to 5 years, she explained. How often the tank should be pumped depends on the size of the tank and the number of people in the household. The more people in the household, the more often the tank may need to be pumped.

For example, a household of two may be fine with pumping the tank every five years; a household of four may need the tank pumped every three years.

Materials flushed will also make a difference.

“In the 1980s, when they put a septic system in, a lot of people wouldn’t even flush toilet paper,” she explained. “Now people flush anything and everything.”

Materials that will not break down naturally in the septic tank will stay there until the tank is pumped out.

Additional factors may also come into play. For example, some cancer patients must have their septic tanks pumped out annually because the medications they take kill off the bacteria that would otherwise help break down the waste.

Anything that goes down the sink or the toilet winds up in the septic tank and can affect its function.

Having the tank pumped out and inspected on a regular basis can also protect the homeowner and the community from a potential health hazard. A broken septic system will leak sewage into the groundwater, Ms. Austin-Neehan explained.

Vacation homes may need the septic tank pumped out more often than those occupied year round, she said. “If the tank isn’t used every day, the bacteria can die off, and sludge builds up.”

She said while there is currently a push for septic-to-sewer conversions, connecting to a “big pipe” sewer system is not possible in rural areas where people live many miles from the nearest town, and it would be too expensive for a utility company to run the pipes. Septic systems can and do work if they are installed and maintained properly by responsible homeowners, she said.

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