About Septic Systems

About Septic Systems

The septic tank performs two functions. First it acts as a holding tank and allows the solids to settle out. Second, naturally occurring anaerobic bacteria begin breaking down the solids in size and destroying the pathogens.
Waste water leaves the house and enters the septic tank. The septic tank performs two functions. First it acts as a holding tank and allows the solids to settle out. The heavier solids sink to the bottom forming the sludge layer, the lighter solids, fats, oils, grease, etc. rise to the surface and form the scum layer. The relatively clear layer in the middle is called effluent. Second, naturally occurring anaerobic bacteria begin breaking down the solids in size and destroying the pathogens. This is a standard septic system. The treatment process starts in the septic tank and is completed in and around the drainfield. This simple type of system is best suited for those ideal building lots: Well-draining soils No high water tables or nearby bodies of water	The Septic Tank Home Wastewater Treatment and Disposal System
Click here to see an animated history lesson of septic systems!
After the treatment process is started in the septic tank, the effluent enters the soil treatment phase of the process (baffles prevent the larger floating solids from entering the drainfield). The soil treatment system, more commonly called the drainfield, is comprised of distribution pipe laid in a trench partially filled with gravel and covered with topsoil. By the time the effluent has traveled 2 - 3 feet through the soil, all the remaining pathogens have been destroyed and the water is drinking quality.
As the effluent enters the drainfield, it percolates through the gravel bed where a large portion of the pathogens are destroyed. Pockets of oxygen created by the uneven shape of the gravel allow the more efficient aerobic bacteria to exist. As the effluent exits the drainfield the natural soil completes the treatment process. By the time the effluent has traveled 2 - 3 feet through the soil, all the remaining pathogens have been destroyed and the water is drinking quality. The cleaning process continues as the water migrates though the soil. Phosphorus and nitrogen are utilized by the vegetative life covering the drainfield and chemically changed in the soil. A large portion of the moisture is returned to the atmosphere through evaporation (evapotranspiration).