Abstract: A pump arrangement that has a pump chamber with an inlet opening and a discharge opening. A discharge pipe is connected to the outlet opening to carry liquid, etc., from the pump chamber. An inlet pipe is connected to the inlet opening and extends downwardly therefrom into the liquid to carry liquid, etc., to the pump chamber. The inlet opening is formed in the pump chamber above the discharge opening. A supply pipe is connected between a source of compressed air and the pump chamber. The supply pipe selectively either supplies compressed air to the pump chamber for exhausting liquid, etc., therefrom via the outlet opening and the discharge pipe or vents the air for intaking liquid, etc., into the pump chamber via the inlet pipe and the inlet opening. The inlet pipe is valve-free, whereby the inlet pipe is open during the entire operation of the pump arrangement so that the pump may pump liquids containing solid objects.

Abstract: An air-driven rotary contact filter for biological cleaning of waste water has spiral channels mounted on a perforated rotatable center pipe having its axis of rotation disposed below the surface of the water whereby the filter is partially submerged with inlets to the channels at the central mixing chamber of the rotor below the water surface and some of the outlets at the periphery of the rotor above the water surface, so that when air is blown axially into the center pipe water is displaced on one side of the rotor whereby the channels will rotate due to the greater weight of water on the other side of the rotor.

Abstract: A rotary system composed of two worms (1 and 2) which are built together and interconnected at their central coils by a pipe conduit (4), said worms having their respective coils oppositely directed to one another and consisting of spirally coiled pipes rotatable about a horizontal axis (3), is used for flushing and aerating a medium which is disposed in the pipes and coated with microorganisms. The microorganisms take up nutrients from waste water (6) in a biological purification process, one worm (1) with part of its periphery immersed in the water (6) lifting quantities of water towards its center, the other worm (2) lowering the water to the original level. This provides for alternate flushing and aeration, and the weight of the water in said second worm (2) provides a torque which contributes towards driving the system.