Abstract: An immersed membrane cassette has a high tank intensity achieved by one or more of: reduced module to module gap; using structural hollow tubing in at least parts of a frame in place of separate permeate and/or air pipes; and, using vertical permeate port connections. The cassette has a tank intensity over 650 m2/m2. The cassette may be combined with a fine screen. This specification also describes an immersed membrane module having a permeate port and/or connector on the top of a header. The permeate connection between the module and a permeate collection tube may be vertical, i.e. perpendicular to the length of the header. A piston seal may be used between the permeate port of the header and the permeate collection tube. The permeate collection tube may be a horizontal structural member on the periphery of a frame that holds the module.

Abstract: A gas sparger produces an intermittent flow of bubbles even if provided with a continuous gas flow. The sparger has a housing to collect a pocket of gas and a conduit to release some of the gas from the pocket when the pocket reaches a sufficient size. Optionally, a cover over an outlet from the conduit may break up or distribute the released gas. A large sparger for use with a commercial membrane module can comprise a plurality of smaller units.

Abstract: A method of air scouring an immersed membrane is described in this specification. The method comprising a step of adjusting one or more aeration parameters: between successive permeation, back pulse or relaxation cycles; during a permeation cycle; or, between a permeation cycle and a backpulse or relaxation cycle.

Abstract: A gas delivery device includes a manifold and a plurality of channels. The manifold is adapted to be connected to a source of a pressurized gas. Each of the plurality of channels is in fluid communication with the manifold through a distinct associated port. Each of the plurality of channels has a generally open bottom.

Abstract: A method of air scouring an immersed membrane is described in this specification. The method comprises a step of adjusting one or more aeration parameters during a permeation cycle, or between a permeation cycle and a back pulse or relaxation cycle, or between successive cycles. The method may be used with a gas delivery device described in this specification in which a supply of gas is provided to a manifold with multiple ports connected to multiple conduits. The method may further comprise bringing a flow of pressurized gas into a tank to near or below the bottom of a membrane module. At about this elevation, the flow of pressurized gas is split into multiple flows of pressurized gas. Each of the multiple flows of pressurized gas is directed to a different lateral position and then released as bubbles.

Abstract: A gas sparger produces an intermittent flow of bubbles even if provided with a continuous gas flow. The sparger has a housing to collect a pocket of gas and a conduit to release some of the gas from the pocket when the pocket reaches a sufficient size. Optionally, a cover over an outlet from the conduit may break up or distribute the released gas. A large sparger for use with a commercial membrane module can comprise a plurality of smaller units.

Abstract: A gas sparger produces an intermittent flow of bubbles even if provided with a continuous gas flow. The sparger has a housing to collect a pocket of gas and a conduit to release some of the gas from the pocket when the pocket reaches a sufficient size. Optionally, a cover over an outlet from the conduit may break up or distribute the released gas. A large sparger for use with a commercial membrane module can comprise a plurality of smaller units.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. Wastewater treatment processes are described. A process to denitrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated as a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square meters per cubic meter of tank volume. A hybrid process has suspended biomass and a membrane supported biofilm.

Abstract: A gas sparger produces an intermittent flow of bubbles even if provided with a continuous gas flow. The sparger has a housing to collect a pocket of gas and a conduit to release some of the gas from the pocket when the pocket reaches a sufficient size. Optionally, a cover over an outlet from the conduit may break up or distribute the released gas. A large sparger for use with a commercial membrane module can comprise a plurality of smaller units.

Abstract: A gas sparger for a filtering membrane system produces an intermittent flow of bubbles even if provided with a relatively continuous gas flow. The sparger has a housing to collect a pocket of gas and a conduit to release some of the gas from the pocket when the pocket reaches a sufficient size. Optionally, a cover over an outlet from the conduit may break up or distribute the released gas. A large sparger for can comprise a plurality of smaller units or areas. The supply of gas to the sparger may vary in flow rate over larger periods of time in response to changes in conditions in the membrane system to change the time between consecutive bursts of bubbles. A gas supply pipe may have two or more outlets at different elevations in communication with each of two or more units or areas.

Abstract: A gas sparger produces an intermittent flow of bubbles even if provided with a continuous gas flow. The sparger has a housing to collect a pocket of gas and a conduit to release some of the gas from the pocket when the pocket reaches a sufficient size. Optionally, a cover over an outlet from the conduit may break up or distribute the released gas. A large sparger for use with a commercial membrane module can comprise a plurality of smaller units.

Abstract: A gas delivery device includes a manifold and a plurality of channels. The manifold is adapted to be connected to a source of a pressurized gas. Each of the plurality of channels is in fluid communication with the manifold through a distinct associated port. Each of the plurality of channels has a generally open bottom.

Abstract: A method of air scouring an immersed membrane is described in this specification. The method comprising a step of adjusting one or more aeration parameters: between successive permeation, back pulse or relaxation cycles; during a permeation cycle; or, between a permeation cycle and a backpulse or relaxation cycle.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. Wastewater treatment processes are described. A process to denitrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated as a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square metres per cubic metre of tank volume. A hybrid process has suspended biomass and a membrane supported biofilm.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. Wastewater treatment processes are described. A process to denitrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated as a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square meters per cubic meter of tank volume. A hybrid process has suspended biomass and a membrane supported biofilm.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. Wastewater treatment processes are described. A process to denitrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated as a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square meters per cubic meter of tank volume. A hybrid process has suspended biomass and a membrane supported biofilm.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. Wastewater treatment processes are described. A process to denitrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated as a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square metres per cubic metre of tank volume. A hybrid process has suspended biomass and a membrane supported biofilm.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. The membranes have an outside diameter of about 200 microns or less and occupy between 0.5% and 4% of the tank volume. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. The membranes may be oriented generally vertically and a spreader may be located near the bottom of the apparatus to disperse the membranes. Wastewater treatment processes are described. A process to dentrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated at a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square metres per cubic metre of tank volume.

Abstract: A gas sparger for a filtering membrane system produces an intermittent flow of bubbles even if provided with a relatively continuous gas flow. The sparger has a housing to collect a pocket of gas and a conduit to release some of the gas from the pocket when the pocket reaches a sufficient size. Optionally, a cover over an outlet from the conduit may break up or distribute the released gas. A large sparger for can comprise a plurality of smaller units or areas. The supply of gas to the sparger may vary in flow rate over larger periods of time in response to changes in conditions in the membrane system to change the time between consecutive bursts of bubbles. A gas supply pipe may have two or more outlets at different elevations in communication with each of two or more units or areas. The discharge of gas between two or more units or areas may be synchronized. One or more of a set of units or area may receive a supplied gas at a higher flow rate.

Abstract: A gas sparger produces an intermittent flow of bubbles even if provided with a continuous gas flow. The sparger has a housing to collect a pocket of gas and a conduit to release some of the gas from the pocket when the pocket reaches a sufficient size. Optionally, a cover over an outlet from the conduit may break up or distribute the released gas. A large sparger for use with a commercial membrane module can comprise a plurality of smaller units.