Abstract: Arrangement for the biological cleaning of water, said arrangement being suitable for large urban stations for cleaning sewage or for the cleaning of waste waters of industrial plants. The arrangement comprises an activating system with pneumatic aeration and a separating system communicating therewith, the arrangement operates on the basis of fluid filtration and automatic return of activated sludge into the activating system by gravitation. Suitable partition walls in a large container form a number of part activating spaces and part separating spaces; by suitable interconnections, by rectifying walls, by the supply of raw water, and by aeration a convenient streaming flow of the liquid and an advantageous operation of the arrangement are obtained.

Abstract: Arrangement for separation of suspensions or emulsions from liquids by flotation having a flotation space widening from the bottom upwards, to be again narrowed from the place of its largest width upwards. The flotation space is formed by a partition wall within a tank, the supply of cleaned liquid terminating into the lower part of the flotation space. The flotated foam is removed at the surface of the top part of the flotation space, with transfer openings above the widest place of the flotation space terminating in a collecting space of cleaned liquid defined by the partition wall and the wall of the tank, a rectifying wall being provided in front of said transfer openings for preventing passage of the flotated suspension to the collecting space of cleaned liquid.

Abstract: An improved technique for reprocessing, through a reaction zone, a portion of an agitated flow of waste water that is coupled into a wedge-shaped or frusto-conical separating zone via such reaction zone is described. A recirculation conduit, independent of an inlet aperture at the bottom of the separating zone for admitting an upward flow of water from the separating zone, has an inlet end communicating with the separating zone at an upper region thereof, the outlet of the recirculation zone emptying into the agitated water stream in the reaction zone. The inlet aperture at the bottom of the separating zone has a cross-sectional area which is small relative to the cross-sectional area of the separating zone and small relative to the cross-sectional area of the reaction zone.

Abstract: A cylindrical reaction chamber for purifying waste water has a separating zone extending substantially along its entire length and bounded transversely by first and second downwardly converging partition walls. The space in the vessel between the vessel wall and the first and second walls form separate waste water activation zones, in at least one of which an aerating device is disposed. Such zones are so configured that separate, oppositely directed transverse swirls of the waste water are established in the respective activating zones. A portion of the agitated water, after suitable treatment by baffle plates to remove the transverse swirling component, is introduced into the bottom of the separating zone for purification via fluid filtration.

Abstract: A reactor, comprising a homogenizing, separating and thickening space has at the bottom a homogenizing space narrowing toward the top and passing over a narrowed opening at the top into a separating space, widening toward the top, with a thickening space connected to the separating space, situated around both these spaces.

Abstract: A gas compressor or motor of the elastic bellows type is provided with improved facilities for maintaining the diaphragm in contact with an actuating member that reciprocates the roll sock between its expanded and compressed positions. An auxiliary piston-cylinder set is disposed within the machine housing to establish a pressure differential between the two sides of the roll sock as the actuating member retracts so that the difference in air pressure maintains the surface of the roll sock firmly in contact with the actuating means. The resulting prevention of collapse of the roll sock permits a full intake of operating air or other gaseous fluid during the suction stroke, and greatly improves the efficiency of the machine.

Abstract: An apparatus for biological and chemical purification of water by agglomeration having a number of parallel, horizontal tanks, aligned side by side, the length of which is larger than their diameter, with inclined conduits advantageously tangential to both adjacent tanks connecting said tanks. The space determined by the inclined walls, adjacent upper parts of the mantles of the tanks, and by front and rear walls serve as a separating space for separating the floccular suspension from the purified water.