Also known as home aeration units, the aerobic treatment unit, or ATU, provides wastewater treatment and storage functions similar to a normal septic tank. By contrast, however, the ATU has a mechanism to inject air into the tank, thereby turning the anaerobic environment aerobic. This allows aerobic bacteria to treat the wastewater resulting in a cleaner effluent than that from a normal septic tank system. The basic ATU consists of an aeration chamber and a settling chamber, with some ATUs also having pretreatment chambers and/or screens to reduce the amount of larger solids entering the aeration chamber. The aeration chamber contains a mechanical stirrer or diffuser lines to add air to the wastewater. Aerated wastewater treatment is more effective and produces a better quality effluent than anaerobic or septic treatment. The improved effluent quality allows ATUs to be used on sites that are not suitable for conventional septic systems.