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 air diffusion members is located in the center of the tank. Above each of the air diffusion members is provided a collector guide surface which collects bubbles as they get too large and channels them to outwardly from the center into a honeycomb filter medium formed in part annular members around the center. The filter medium receives the air and directs it back into the center around the guide surface to act as a growth medium for a biomass of bacteria.

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.

Abstract: There is provided an apparatus for developing a propulsion force in a predetermined direction. The apparatus includes an outer frame and an inner frame slidably mounted within the outer frame. The inner frame supports a flywheel which rotates about a shaft defining a first axis. Masses are mounted to the flywheel for rotational movement with the flywheel and for lateral movement relative to the flywheel in a direction to increase and decrease a distance of a center of gravity of the masses from the first axis. The outer frame supports a mass movement control member rotating with the flywheel about a second axis parallel to the first axis. The control member moves the masses cyclically such that the distance from the first axis is at a maximum in the direction of propulsion and at a minimum in a direction opposite to the direction of propulsion.