Owning a septic system requires maintenance to ensure you get the most life out of the system. The first step in providing maintenance, is understanding how the system works.
A septic system contains two major components: a septic tank and the absorption field. The septic tank is usually made of concrete, fiberglass, or plastic and is buried and watertight. Some very old systems may still utilize steel tanks , which are considered antiquated. These type of systems will likely need replacement. All septic tanks should have baffles (internal slabs or tees) at the inlet and outlet to insure proper flow patterns. Most septic tanks are single compartment tanks or two tanks in a series. Today's newer sand mount systems generally utilize two tanks. One, the septic tank(treatment tank) which retains the solids. Two, the dosing tank. This tank has a mechanical pump and electrical components that through a series of floats provide a pressurized dose of effluent to the absorption area.
The wastewater is passed onto the absorption field through a connection pipe. The absorption field is also known as the drain field or leach field. The absorption field contains a series of underground-perforated pipes that are commonly, but not always, connected in a closed loop system. The wastewater is distributed to the entire absorption field through the perforated pipes. The absorption field which is located in the unsaturated zone of the soil, treats the wastewater through an oxygenated digestion process and removes the remaining impurities before the wastewater returns to the ground water.
The wastewater coming out of the septic tank is a cloudy liquid that still contains many disease-causing germs. When this water flows into the perforated pipe in the absorption field and exits through the holes in the pipe and trickles through the rock or gravel where it is stored until it is absorbed by the soil. In some systems, subsurface chambers store this effluent. As the effluent enters and flows through the unsaturated soil, many bacteria that can cause disease are filtered out. Some of the other smaller germs, such as viruses, are trapped and held by the soil molecules until they die. The soil can also retain certain nutrients such as phosphorus and some forms of nitrogen.
Understanding how the system works will give you the necessary information in outlining an effective plan for maintaining your septic system, and ultimately extending it's life. It is very important to properly maintain your system. While maintaining your system is another whole article, it's suffice to say that one should pump these tanks a minimum every two years.