First lets see what every wastewater system should do.

Wastewater systems should:

• Take the water away
• Treat the water
• Protect public health and the environment

This is true for onsite systems as well municipal treatment plants. A septic tank system although very simple in design does all of these things very well. It takes the wastewater from your home, and allows the naturally occurring bacteria in the soil to treat the water.

• First by settling the solids that enter the tank (clarification).
• Then bacteria in the soil treat the water, as it moves through the field lines.
• The clean water then returns to ground water.

TYPICAL SYSTEMS: (gravity)

All wastewater from the house comes to a central drain. This one drain leaves the house and runs into the septic tank. Although some tanks are made of plastic or fiberglass, most tanks are made of concrete. A tank for a single-family residence (three or four bedroom) is 1000-gallon capacity, and measures approximately 4.5’w x 9’l x5’d.

Side view of a typical septic tank.

Septic tanks have one inlet and one outlet. By design the inlet is higher than the outlet. The outlet level determines the water level of the tank. A tank at its proper water level is always below the inlet pipe; this allows the inlet to remain empty between uses. A baffle divides the tank. This baffle is open at the bottom and half way up. Its primary purpose is to hold floating solids on the inlet side of the tank. The outlet tee serves the same purpose, keeping any floating solids that may have passed the baffle from entering the field lines. All new systems are installed with effluent filters in the outlet tee.

The field lines are a series of trenches in the yard that allow the effluent from the septic tank to return to the ground for final treatment. While the septic tank catches and holds the solid waste, the field lines and the soil that surrounds them are the final treatment where naturally occurring bacteria break down pathogens in the tank effluent.

Simple, yet effective, septic tanks are part of the solution for our growing concerns about a cleaner environment. Handling wastewater onsite in small quantities is a key to better management of tax revenues for other areas.