Abstract: A waste water evaporation system includes an elongated evaporation bed having an upper layer of rock pieces and a lower sand layer. A perforated pipe extends in the rock layer to slowly deliver waste water for percolation into the sand layer; and a lower layer of rock pieces under the sand layer may receive drainage of excess water for recirculation to the top layer via a sump and pump.

Abstract: A method of treating liquid sewage, including solids, includes(a) collecting the solids in a horizontally elongated narrow zone at the bottom of a sewage pond,(b) generating a stream of gas bubbles, and(c) successively subjecting said solids lengthwise of said zone to impingement of said stream.

Abstract: Odor suppression in a septic tank sewage system involves reception of sewage in a septic tank wherein solids are allowed to settle; receiving liquids discharging from the septic tank into an enclosed aeration zone outside the septic tank; agitating the liquids in the aeration zone and delivering a stream of air into the liquids being agitated; and draining aerated liquid from that zone, these and other steps are carried out in a particular manner, of unusual advantage.