Abstract: An opposed-piston compressor has a rigid yoke which interconnects the pistons, and a drive comprising a crankshaft and balance weights within the yoke, enabling the shaft bearings to be placed close to the center line of the pistons.

Abstract: An apparatus for the anaerobic digestion of natural organic waste comprises a feed tank, a digester and an outlet tank. There is further provided feed means which feeds waste to be digested from the feed tank to the digester at an adjustable continuous rate. A gas pump may be used to recirculate from the top of the digester through a diffuser to the bottom of the digester. A suitable gas pump comprises a container partially filled with liquid so as to provide a space above the liquid surface and within the container sealed by the liquid from the exterior of the container, pumping means being provided in the said space.

Abstract: In a cylonic incinerator for burning liquid and solid wastes, one or more scraper bars are suspended by a non-rigid suspension from support arms projecting from a vertical driven shaft, so as to spread and disturb the waste on the floor of the incinerator.

Abstract: A sewage treatment apparatus of the activated sludge extended aeration type, particularly for use on board ships, comprises an inverted cone-shaped settling tank extending downwardly into an aerating tank. Sewage entering the aerating tank is constrained to flow around the outside of the settling tank, during which time it is aerated. The aerated liquid is then transferred to the settling tank, where sludge settling to the bottom thereof is removed and fed back to the aerating tank. An outlet means for removing treated liquid from just below the liquid surface in the settling tank is disposed at the center of said tank.