Abstract

An on-site wastewater treatment system is disclosed suitable for domestic or other sewage. After separation of the settleable solids from incoming wastewater by means of a septic tank or other means the effluent is passed into a basin holding particles of a media through which the effluent travels. The media bed removes a substantial amount of the suspended solids in the effluent and some of the BOD (biological oxygen demand material). The filtrate is collected and uniformly dispersed, preferably by spraying, over the surface of the same media bed for travel therethrough a second time. The effluent carries oxygen from the air into the media. The media retains the effluent until the surface tension of the effluent between the particles of the media bed is overcome by gravity, at which time it is displaced from the media and discharged. During the retention time aerobic action in the media bed reduces the bacterial count of the effluent significantly. The effluent from the septic tank is preferably alternately distributed between a first area of the media bed and a separate second area of the media bed in order to allow continuous regeneration of the media bed by avoiding a continuously ponded condition and by the action of the aerated effluent.