Anaerobic systems and aerobic lagoon systems are the most common types of septic tank systems. Mechanical hybrid systems that combine aerobic and anaerobic functions are rarely used. Septic tanks are typically made of concrete, fiberglass or plastic.
A traditional septic waste water system has three basic components: a watertight holding tank, a drain field and the soil beneath the drain field. A typical septic tank holds 1,000 to 1,500 gallons of effluent and is buried near a home.
Aerobic septic systems use bacteria to decompose solid waste that sinks to the bottom of the tank. Liquid waste moves through pipes near the top of the tank and flows to the drain field. Septic tank systems typically require pumping every three to five years.