A structure adapted to be at least partially immersed in a liquid to be purified, in particular sewage, the structure comprising: a hollow body provided with at least one inlet opening and at least one outlet opening for the liquid; first dispensing means adapted to dispense an oxygen-containing gas, for example air, arranged so as to generate a flow of fluid, in particular a mixture of sewage and said gas, towards said at least one outlet opening; second dispensing means adapted to dispense an oxygen-containing gas, for example air, arranged so as to generate a flow of fluid, in particular a mixture of sewage and said gas, outside the hollow body.

An aerator for treating wastewater is configured to produce air bubbles to mix and circulate wastewater within a treatment facility. Additionally, the aerator is configured to inject additive into the wastewater at the same time as the air bubbles are being produced, so that roiling of the air bubbles and/or circulation induced by the air bubbles rising within the water column facilitates mixing of the additive with the wastewater.

An apparatus for degrading the organic fraction of sewage by means of active biomass, in particular active sludge particles, comprising: —at least one tank (1) adapted to contain the sewage and said active biomass; —at least one hollow structure (6, 106, 206), adapted to be at least partially immersed in the sewage, provided with at least one first opening (61) for letting in the sewage and with at least one second opening (62) for letting out the sewage, wherein the ratio between the area of the at least one first opening (61) and the area of the at least one second opening (62) is equal to at least 5:1; —air delivery means (7, 70) adapted to introduce air inside said at least one structure (6, 106, 206); wherein said at least one first opening (61) is proximal to said air delivery means (7, 70) and said at least one second opening (62) is distal from said air delivery means (7, 70), so that the air delivery means (7, 70) are adapted to generate a flow of sewage from said at least one first opening (61) to said at least one second opening (62).

A floating aerator that is highly efficient in oxygenating water and wastewater utilizes high-volume, low pressure air that is diffused into a sub-surface oxygen transfer chamber in which water and wastewater is oxygenated. An air lift is created in the oxygen transfer chamber through the discharge of air bubbles in the water column in the aerator. The aerator comprises a floating head having a concave lower surface, a main chamber or barrel that defines the oxygen transfer chamber, and an air diffuser that extends coaxially through the float head and barrel interconnects the float head to the barrel such that there is a discharge slot defined between the lower surface of the float head and the barrel. A ballast ring floats the aerator at the desire level such that a flow of air bubbles and oxygenated water or wastewater are discharged at a subsurface level.

The present invention relates to a reaction device with air-lift type internal circulation which includes: a vertical cylindrical volume (1), more than one draft tube vertical element (2) positioned within the cylindrical volume (1) in such a manner as to form an gap with the walls of said volume, more than one gas distributor (3), each of which is positioned on the bottom of said device; wherein: each vertical internal element (2) has an internal diameter which increases along the vertical axis of said element, and the ratio between the total height of the reaction device and the internal diameter of the reaction device is less than 1.

An aeration nozzle is provided, having on one end an air supply port (16a) connected to an aeration pump (13) and a waste water suction port (17) for suctioning waste water in a processing tank (3, 4), and having a micro-bubble generation unit (18), provided facing the air supply port, for mixing air supplied by the air supply port and waste water suctioned from the waste water suction port and generating micro-bubbles (9), wherein a plurality of blades of cylindrical micro-bubble generators (19) included in the micro-bubble generation unit (18) is configured such that tip ends of the blades are formed so as to face one another around the center of the cylindrical micro-bubble generators (19a, 19b); and by being formed from an elastic member (such as rubber), the tip ends of the blades are configured so as to bend with the base ends as starting points.

The invention relates to a stirred tank reactor for gas-liquid mass transfer in a slurry. The reactor includes a reactor tank (1) having a first volume (V.sub.1), a drive shaft (2) that extends vertically in the reactor tank, a motor (3) for rotating the drive shaft (2), a main impeller (4) which is a downward pumping axial flow impeller attached to the drive shaft (2) to create a main flow pattern in the reactor tank, and a gas inlet (5) arranged to supply gas into the reactor tank (1) to be dispersed to the liquid. The reactor includes a mechanical gas sparging apparatus (6) comprising a dispersion chamber (7) having a second volume (V.sub.2) which is substantially smaller than the first volume (V.sub.1) of the reactor tank (1), the dispersion chamber being arranged coaxial with the drive shaft (2), and the gas inlet (5) being arranged to feed gas into the dispersion chamber (7), and mixing means (8, 9, 10, 11, 12) arranged within the dispersion chamber (7) for mixing the gas into liquid by dispersing the gas to fine bubbles before the bubbles enter the main flow pattern. The mixing power per unit volume inside the dispersion chamber (7) is significantly larger than the mixing power elsewhere in the reactor.

A submersible aerator includes a hollow cylindrical housing having an open upper end, an open lower end and a hollow interior. An air supply hose extends from an air supply source into the upper end of the housing and terminates at an air outlet, immediately above the lower end of the housing. Attached to the interior surface of the housing outer wall are a series of vertically spaced, oppositely facing baffle plates that provide impact surfaces to cleave rising air bubbles into smaller bubbles. A weep hole is formed on the outer surface of the air supply hose, equidistantly positioned between each adjacent pair of baffle plates. Accordingly, excess air pressure will be relieved via the weep holes as opposed to the lower end of the housing to protect nearby external equipment.

An apparatus for degrading the organic fraction of sewage by means of active biomass, in particular active sludge particles, comprising: —at least one tank (1) adapted to contain the sewage and said active biomass; —at least one hollow structure (6, 106, 206), adapted to be at least partially immersed in the sewage, provided with at least one first opening (61) for letting in the sewage and with at least one second opening (62) for letting out the sewage, wherein the ratio between the area of the at least one first opening (61) and the area of the at least one second opening (62) is equal to at least 5:1; —air delivery means (7, 70) adapted to introduce air inside said at least one structure (6, 106, 206); wherein said at least one first opening (61) is proximal to said air delivery means (7, 70) and said at least one second opening (62) is distal from said air delivery means (7, 70), so that the air delivery means (7, 70) are adapted to generate a flow of sewage from said at least one first opening (61) to said at least one second opening (62).

The invention relates to the design of an enclosure for a membrane aeration module, which incorporates a reversible, low-pressure, air-lift pump to encourage a vertical water flow through and between the membranes in the module. These enclosed membrane modules are suitable for use in membrane aerated biofilm reactors, which are used to treat water or wastewater.