Septic Systems:

Septic systems are used when sewage treatment plants are not accessible. They safely treat and dispose of wastewaters produced in the bathroom, kitchen, and laundry. These wastewaters may contain disease-causing germs and pollutants that must be treated to protect human health and the environment. Although septic systems are usually a permanent solution to wastewater treatment and disposal, they sometimes serve as a temporary solution until sewer lines are installed.

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Drainfield:

The real treatment of the wastewater occurs in the soil beneath the drainfield. Sewage effluent flows out of the tank as a cloudy liquid that still contains many disease-causing germs and environmental pollutants. Effluent flows into the perforated pipe in the trenches, passes through the holes in the pipe, and then trickles down through the gravel to the soil. As effluent enters and flows through the soil, many of the bacteria that can cause diseases are filtered out. Some of the smaller germs, such as viruses, are adsorbed by the soil until they are destroyed. The soil can also retain certain chemicals, including phosphorus and some forms of nitrogen.

Usually, the drainfield can fit within the front yard or the backyard of a typical 1-acre homesite. The precise area requirements will depend upon the kinds of soils at the homesite, the size of the house (the number of bedrooms), and the topography of the lot. A site with clayey, slowly permeable soils needs a larger drainfield to absorb the sewage effluent than does a site with sandy, permeable soils. Adequate land area must be available to isolate the entire septic system from any nearby wells, springs, streams, lakes, or other bodies of water. There also must be enough area to install a replacement system in case it is ever needed. This replacement area must meet the same soil and site requirements as the original system.