Abstract: Waste household liquid containing solid fecal content so as to include potentially toxic bacterial content is collected in a septic tank and periodically discharged through a pipe where a quantity of hydrogen peroxide is injected into the pipe to be mixed with the waste liquid. The pipe carries the liquid to a centrifugal separator to separate the solid content from the liquid so that the solid content free from toxic bacterial content is collected and the waste liquid with the solid content removed is discharged for re-use or for disposal to the ground.

Abstract: An aeration tank used in a method of treating effluent includes a pipe for transporting the effluent from the source to the tank bottom and a discharge duct having a siphon effect for tapping off an overflow from the tank as more effluent is added from the source. An array of generally horizontal pipes is located in the tank having a series of exit holes along their length and connected to an air plenum at one side wall for feeding air into the end of each of the pipes, the pipes being arranged in columns one above another such that the air escapes from the pipes of the array through the holes to inject air into the effluent in the tank at positions spaced transversely, longitudinally and vertically. The pipes have flat upper discharge surfaces. Above each pipe is provided a collector channel which collects bubbles as they get too large and channels them to one end to be replaced by fresh small bubbles from a next above pipe.