A wastewater treatment and dispersal system wherein wastewater will stand until it has a BOD of less than about 125 mg/l. The dispersal field may comprise inner and outer conduits, an inner conduit and a permeable outer cover, or a trough and an enclosure....http://www.google.es/patents/US7300577?utm_source=gb-gplus-sharePatente US7300577 - Wastewater treatment and dispersal system
