There are two types of primary treatment for a household sewage treatment system, septic tanks and aeration units. The septic tank is designed to separate the solids from the liquids in the wastewater that leaves your home. The solids collect on the bottom of the septic tank and the grease and scum rise to the top, between two or more baffles. The liquid pass around baffles and through the septic tank for further treatment in an absorption field. Primary treatment using an aeration unit breaks down and treats sewage through the use of aerobic bacteria, which thrive on oxygen pumped into the tank by an electric motor.
There are generally two types of household sewage treatment systems, onsite and off-site. Onsite systems vary by design, but the main goal is to keep all wastewater generated at the site confined to the site. Soil absorption fields are utilized as the final treatment and disposal components, and may be preceded by either a septic or aeration tank, depending on the soil characteristics. Off-site systems typically consist of an aeration unit, followed by a continuous disinfection system, and discharge “off-site” to a nearby lake, stream or ditch. These off-site systems may only be installed when an onsite system is no feasible, and generally require special approval and permits from the Ohio E.P.A.