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The Septic Tank
Home » Plumbing » Septic Systems » The Septic TankSewer systems are too expensive for rural communities that have houses spread apart. For these houses, the septic tank is a good alternative. A septic tank holds on average about 1,000 gallons of water. It is made of concrete of steel and is buried in the backyard. Wastewater flows into the tank and separates itself into three layers. The first layer is the scum layer. Anything that is floating on the surface of the water is found here. The second layer is mostly clear water. This clear water contains bacteria and chemicals that act as fertilizers. This water eventually flows back out into the ground. The third layer is the sludge layer. Anything heavier than water sinks to the bottom to make up this layer.
Septic tanks produce gases as a result of the breakdown of organic material. To prevent this gas from leaking into the house, sinks are equipped with P-traps, which block the gases and force them up a vent pipe instead, which leads to the roof.
As water flows into the septic tank, it displaces the old water, which flows into the drain field. The drain field is a series of pipes that disperse the water into the ground. The type of soil surrounding the septic system determines how big your drain field needs to be. If the ground readily absorbs water, the drain field can be small, but if the soil is hard clay, for example, the drain field needs to be much bigger. The drain field pipes are buried in trenches that are about 4-6 feet deep. The first 2-3 feet of the trench is filled with gravel, and the remaining depth is filled in with dirt.
Septic systems require nothing but gravity to operate. They are completely passive systems.
Related Septic Systems Articles
- The Sewer System
- The Septic Tank
- Pumping your Septic System
- Caring for your Septic System
- Early Warning Signs of System Failure