Apparatus is disclosed for separating an amount of a substance from groundwater, comprising an elongate chamber (18) having an inlet (22) which is arranged in use to admit groundwater into the chamber near a lower first end (24). There is also a gas sparger (26) located near the first end (24) which admits gas into the chamber for inducing groundwater to flow from the first end (24) of the chamber toward a second end upper end, and for producing a froth layer (32) which rises above an interface with the groundwater including a concentrated amount of the substance. A suction hood (38) can be moved downward from the top of the chamber (18) into a position to collapse the froth layer (32) and to cause it to be removed from the well body (14). The suction hood (38) (acting as a froth depth regulation device) controls the amount of groundwater in the froth layer (32), which influences the concentration of the contaminant substance achieved in the froth layer (32).

A bioreactor may comprise a head-plate configured to provide coupling features to attach selected components to the bioreactor. The bioreactor may also comprise impeller and sparger, and the sparger is positioned at a pre-determined distance from the impeller based at least in part on a spatial configuration of the head-plate. The bioreactor further comprises a vessel defining a hollow enclosure for receiving a culture medium, and an opening of the vessel is covered by the head-plate.

An aerator device, a filter system including an aerator device, and a method of aerating a filter using an aerator device. An aerator device includes a housing having an interior cavity; a first plate in the interior cavity and defining a first cavity portion and a second cavity portion thereof, the first plate being spaced apart from a top wall of the housing to define a first opening through which the first cavity portion and the second cavity portion are in communication; and a second plate defining a first chamber and a second chamber of the second cavity portion, the first chamber and the second chamber being in communication with each other below a lower end of the second plate, the housing having an inlet opening in communication with the first cavity portion, and an outlet opening through the top wall and in communication with the second chamber.

Apparatus is disclosed for separating an amount of a substance from groundwater, comprising an elongate chamber (18) having an inlet (22) which is arranged in use to admit groundwater into the chamber near a lower first end (24). There is also a gas sparger (26) located near the first end (24) which admits gas into the chamber for inducing groundwater to flow from the first end (24) of the chamber toward a second end upper end, and for producing a froth layer (32) which rises above an interface with the groundwater including a concentrated amount of the substance. A suction hood (38) can be moved downward from the top of the chamber (18) into a position to collapse the froth layer (32) and to cause it to be removed from the well body (14). The suction hood (38) (acting as a froth depth regulation device) controls the amount of groundwater in the froth layer (32), which influences the concentration of the contaminant substance achieved in the froth layer (32).

Apparatus is disclosed for separating an amount of a substance from groundwater, comprising an elongate chamber (18) having an inlet (22) which is arranged in use to admit groundwater into the chamber near a lower first end (24). There is also a gas sparger (26) located near the first end (24) which admits gas into the chamber for inducing groundwater to flow from the first end (24) of the chamber toward a second end upper end, and for producing a froth layer (32) which rises above an interface with the groundwater including a concentrated amount of the substance. A suction hood (38) can be moved downward from the top of the chamber (18) into a position to collapse the froth layer (32) and to cause it to be removed from the well body (14). The suction hood (38) (acting as a froth depth regulation device) controls the amount of groundwater in the froth layer (32), which influences the concentration of the contaminant substance achieved in the froth layer (32).

Apparatus is disclosed for separating an amount of a substance from groundwater, comprising an elongate chamber (18) having an inlet (22) which is arranged in use to admit groundwater into the chamber near a lower first end (24). There is also a gas sparger (26) located near the first end (24) which admits gas into the chamber for inducing groundwater to flow from the first end (24) of the chamber toward a second end upper end, and for producing a froth layer (32) which rises above an interface with the groundwater including a concentrated amount of the substance. A suction hood (38) can be moved downward from the top of the chamber (18) into a position to collapse the froth layer (32) and to cause it to be removed from the well body (14). The suction hood (38) (acting as a froth depth regulation device) controls the amount of groundwater in the froth layer (32), which influences the concentration of the contaminant substance achieved in the froth layer (32).

A gas diffusion system configured to feed a gas stream, in particular a passivating gas stream, into an apparatus, in particular a decomposer, of a urea plant; the system extends along an axis and has a gas feed conduit having an outlet from which the gas flows substantially parallel to the axis, and a diffuser assembly configured to diffuse the gas supply from the conduit; the diffuser assembly is shaped so as to intercept the gas stream flowing axially from the outlet, and divert the gas stream substantially radially with respect to the axis and uniformly about the axis.