How Does a Septic Tank Work?


How Does a Septic Tank Work?

A septic tank system is a concrete, fiberglass or polyethylene — plastic — tank. It is used as a private sewage treatment plant in rural areas where municipal sewage system is not practical or too expensive to install. Common storage capacities range between 1000 to 1500 gallons. The size needed depends mostly on the square footage of the home and the number of people who reside there. Learning how your septic system works can help you avoid costly repairs in the future.

Septic Tank Basics

There are three main components of a standard septic system: the tank, the drain field and the soil beneath the drain field.

  • The tank provides a storage area that allows the solids to separate from the effluent and partially decompose while allowing the liquid to flow into the drain field.
  • The drain field, also known as a leach field or absorption field, disperses the effluent into the surrounding soil.
  • The soil below the drain field is the final step in the treatment process and is very important. Organisms in the drain field soil treat the effluent before it eventually enters the ground below it.

How It Works

As your home’s wastewater travels through its drain system and enters the septic tank, heavy solids sink to the bottom forming the sludge layer. Lighter materials rise to the top and form the scum layer. Effluent — greywater — makes up the middle layer. Bacteria in the tank decompose about 50 percent of the solids. The remaining solids must be removed periodically by pumping to avoid drain field contamination. The effluent enters the drain field where it eventually percolates into the ground.

Maintaining Your Septic System

Many things can have an adverse impact on your septic system. Excessive water use, household cleaners and too much organic matter — garbage disposal — entering the tank can cause a failure. Use water conservatively whenever possible. Install low-flow showerheads and high-efficiency bathroom fixtures to reduce the amount of water entering the tank. Avoid harsh, household cleaners and use the garbage disposal sparingly to maintain a healthy septic system.

In addition, have your septic system pumped periodically — at least every three years — to remove sludge and scum buildup before it enters your drain field. Sludge and scum contain particles that will clog your drain field and render it inoperable. If this happens, the effluent cannot drain and the system will back up leading to costly drain field repairs.

For answers to your questions, contact The Pink Plumber today.

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