Septic systems are individual on-site wastewater treatment systems that use bacteria and the soil to treat our wastewater. A basic septic system consists of a septic tank, a distribution box, and a drain field—all connected by a pipe system.
The septic tank begins to treat your household wastewater by temporarily holding it in the first compartment of the tank. Here, heavy solids and lighter scum are allowed to separate from the wastewater. This is called the primary treatment. The solids stored in the tank are decomposed by bacteria. That which is not broken down, along with grease and other floating scum, must be removed periodically by a professional septic pumper.
In the second compartment of the septic tank, more solids settle out, allowing the relatively clear wastewater to leave the tank and flow into a distribution box. This separates the water flow into a network of drain field trenches. Drainage holes in the trench pipes allow the water to filter through the surrounding gravel and ultimately seep slowly into the surrounding soil. Bacteria and other microorganisms in the soil further treat and purify the liquid; this is called the secondary treatment. A properly functioning septic system does not pollute the groundwater and should function for many years.
The Septic Tank SystemThe septic tank system is a small on-site sewage treatment and disposal system buried in the ground. The septic system has 2 essential parts: (1) the septic tank and (2) the soil absorption area.
The Septic TankThe modern septic tank is a watertight box usually made of pre-cast concrete, concrete blocks, or reinforced fiberglass. When household waste enters the septic tank, several things occur:
- Organic solid material floats to the surface and forms a layer of what is commonly called scum. Bacteria in the septic tank biologically converts this material to liquid.
- Inorganic or inert materials and the by-products of bacterial digestion sink to the bottom of the tank and form a layer commonly known as sludge.
- Only clear water should exist between the scum and sludge layers. It is this clear water—and only this clear water— that should overflow into the soil absorption area.
Solid material overflowing into the soil absorption area should be avoided at all costs. It is this solids overflow that clogs soil spores and causes systems to fail. Two main factors cause solid material to build up enough overflow: bacterial deficiency and lack of sludge removal.
Bacteria must be present in the septic tank to break down and digest the organic solids. Normal household waste provides enough bacteria to digest the solids unless any harm is done to the bacteria.