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: Wastewater is treated though primary treatment of the water by way of a micro-sieve to produce a primary effluent and primary sludge. There is secondary treatment of the primary effluent by way of a membrane bioreactor (MBR) or an integrated fixed film activated sludge (IFAS) reactor to produce a secondary effluent and a waste activated sludge. The micro-sieve may have openings of 250 microns or less, for example about 150 microns. In a process, a gas transfer membrane is immersed in water. Pressurized air flows into the gas transfer membrane. An exhaust gas is withdrawn from the gas transfer membrane and used to produce bubbles from an aerator immersed in the water.

Abstract: Wastewater is treated though primary treatment of the water by way of a micro-sieve to produce a primary effluent and primary sludge. There is secondary treatment of the primary effluent by way of a membrane bioreactor (MBR) or an integrated fixed film activated sludge (IFAS) reactor to produce a secondary effluent and a waste activated sludge. The micro-sieve may have openings of 250 microns or less, for example about 150 microns. In a process, a gas transfer membrane is immersed in water. Pressurized air flows into the gas transfer membrane. An exhaust gas is withdrawn from the gas transfer membrane and used to produce bubbles from an aerator immersed in the water.

Abstract: An apparatus has a plurality of gas transfer membranes. The apparatus floats in water with the membranes submerged in the water. To treat the water, a gas is supplied to the membranes and is transferred to a biofilm supported on the membranes or to the water. Gas is also used to supply mixing or membrane scouring bubbles to the water. The mixing or scouring bubbles can be provided by a cyclic aeration or other gas supply system, which optionally provides gas at a variable pressure to the membranes in parallel or series with an aerator. Condensates can be removed from the membranes, and exhaust gasses from the membranes can be monitored, optionally through one or more dedicated pipes.

Abstract: An apparatus has a plurality of gas transfer membranes. The apparatus floats in water with the membranes submerged in the water. To treat the water, a gas is supplied to the membranes and is transferred to a biofilm supported on the membranes or to the water. Gas is also used to supply mixing or membrane scouring bubbles to the water. The mixing or scouring bubbles can be provided by a cyclic aeration or other gas supply system, which optionally provides gas at a variable pressure to the membranes in parallel or series with an aerator. Condensates can be removed from the membranes, and exhaust gasses from the membranes can be monitored, optionally through one or more dedicated pipes.

Abstract: A conventional media filter such as a gravity sand filter is converted into a membrane filter. The media is removed and replaced by immersed membrane modules. Transmembrane pressure is created by a static head pressure differential, without a suction pump, thereby creating a membrane gravity filter (MGF). Preferred operating parameters include transmembrane pressure of 5-20 kPa, 1-3 backwashes per day, and a flux of 10-20 L/m2/h. The membranes are dosed with chlorine or another oxidant, preferably at 700 minutes*mg/L as Cl2 equivalent per week or less. The small oxidant does is believed to provide a porous biofilm or fouling layer without substantially removing the layer. The media filter may be modified so that backwash wastewater is removed from near the bottom of the tank rather than through backwash troughs above the membrane modules. Membrane integrity testing may be done while the tank is emptied after a backwash.

Abstract: A conventional media filter such as a gravity sand filter is converted into a membrane filter. The media is removed and replaced by immersed membrane modules. Transmembrane pressure is created by a static head pressure differential, without a suction pump, thereby creating a membrane gravity filter (MGF). Preferred operating parameters include transmembrane pressure of 5-20 kPa, 1-3 backwashes per day, and a flux of 10-20 L/m2/h. The membranes are dosed with chlorine or another oxidant, preferably at 700 minutes*mg/L as Cl2 equivalent per week or less. The small oxidant does is believed to provide a porous biofilm or fouling layer without substantially removing the layer. The media filter may be modified so that backwash wastewater is removed from near the bottom of the tank rather than through backwash troughs above the membrane modules. Membrane integrity testing may be done while the tank is emptied after a backwash.

Abstract: A conventional media filter such as a gravity sand filter is converted into a membrane filter. The media is removed and replaced by immersed membrane modules. Transmembrane pressure is created by a static head pressure differential, without a suction pump, thereby creating a membrane gravity filter (MGF). Preferred operating parameters include transmembrane pressure of 5-20 kPa, 1-3 backwashes per day, and a flux of 10-20 L/m2/h. The membranes are dosed with chlorine or another oxidant, preferably at 700 minutes*mg/L as Cl2 equivalent per week or less. The small oxidant does is believed to provide a porous biofilm or fouling layer without substantially removing the layer. The media filter may be modified so that backwash wastewater is removed from near the bottom of the tank rather than through backwash troughs above the membrane modules. Membrane integrity testing may be done while the tank is emptied after a backwash.

Abstract: A membrane bioreactor (MBR) has membranes comprising a supporting structure. A supply unit doses a sorbent such as powdered activated carbon (PAC) into the MBR. The PAC is maintained at a concentration in the mixed liquor of 200 mg/L or more. Mixed liquor with the sorbent particles recirculates within the MBR at a flow rate of at least twice the feed flow rate. Air bubbles are provided to scour the membranes including during at least part of a permeation step. The sorbent particles are present in the mixed liquor and contact the membranes. Bioaugmentation products may be immobilized on PAC or other carriers and then added to an MBR or other bioreactors.

Abstract: A conventional media filter such as a gravity sand filter is converted into a membrane filter. The media is removed and replaced by immersed membrane modules. Transmembrane pressure is created by a static head pressure differential, without a suction pump, thereby creating a membrane gravity filter (MGF). Membrane permeate passes through a bed of adsorption media optionally located in a tank with the membrane modules. The membranes are backwashed periodically with permeate, which bypasses the adsorption media as it returns to the membrane module.

Abstract: Wastewater is treated though primary treatment of the water by way of a micro-sieve to produce a primary effluent and primary sludge. There is secondary treatment of the primary effluent by way of a membrane bioreactor (MBR) or an integrated fixed film activated sludge (IFAS) reactor to produce a secondary effluent and a waste activated sludge. The micro-sieve may have openings of 250 microns or less, for example about 150 microns. In a process, a gas transfer membrane is immersed in water. Pressurized air flows into the gas transfer membrane. An exhaust gas is withdrawn from the gas transfer membrane and used to produce bubbles from an aerator immersed in the water.

Abstract: Wastewater is treated though primary treatment of the water by way of a micro-sieve to produce a primary effluent and primary sludge. There is secondary treatment of the primary effluent by way of a membrane bioreactor (MBR) or an integrated fixed film activated sludge (IFAS) reactor to produce a secondary effluent and a waste activated sludge. The micro-sieve may have openings of 250 microns or less, for example about 150 microns. In a process, a gas transfer membrane is immersed in water. Pressurized air flows into the gas transfer membrane. An exhaust gas is withdrawn from the gas transfer membrane and used to produce bubbles from an aerator immersed in the water.

Abstract: A conventional media filter such as a gravity sand filter is converted into a membrane filter. The media is removed and replaced by immersed membrane modules. Transmembrane pressure is created by a static head pressure differential, without a suction pump, thereby creating a membrane gravity filter (MGF). Preferred operating parameters include transmembrane pressure of 5-20 kPa, 1-3 backwashes per day, and a flux of 10-20 L/m2/h. The membranes are dosed with chlorine or another oxidant, preferably at 700 minutes*mg/L as Cl2 equivalent per week or less. The small oxidant does is believed to provide a porous biofilm or fouling layer without substantially removing the layer. The media filter may be modified so that backwash wastewater is removed from near the bottom of the tank rather than through backwash troughs above the membrane modules. Membrane integrity testing may be done while the tank is emptied after a backwash.

Abstract: An apparatus has a plurality of gas transfer membranes. The apparatus floats in water with the membranes submerged in the water. To treat the water, a gas is supplied to the membranes and is transferred to a biofilm supported on the membranes or to the water. Gas is also used to supply mixing or membrane scouring bubbles to the water. The mixing or scouring bubbles can be provided by a cyclic aeration or other gas supply system, which optionally provides gas at a variable pressure to the membranes in parallel or series with an aerator. Condensates can be removed from the membranes, and exhaust gasses from the membranes can be monitored, optionally through one or more dedicated pipes.

Abstract: Wastewater is treated though primary treatment of the water by way of a micro-sieve to produce a primary effluent and primary sludge. There is secondary treatment of the primary effluent by way of a membrane bioreactor (MBR) or an integrated fixed film activated sludge (IFAS) reactor to produce a secondary effluent and a waste activated sludge. The micro-sieve may have openings of 250 microns or less, for example about 150 microns. In a process, a gas transfer membrane is immersed in water. Pressurized air flows into the gas transfer membrane. An exhaust gas is withdrawn from the gas transfer membrane and used to produce bubbles from an aerator immersed in the water.

Abstract: A membrane bioreactor (MBR) has membranes comprising a supporting structure. A supply unit doses a sorbent such as powdered activated carbon (PAC) into the MBR. The PAC is maintained at a concentration in the mixed liquor of 200 mg/L or more. Mixed liquor with the sorbent particles recirculates within the MBR at a flow rate of at least twice the feed flow rate. Air bubbles are provided to scour the membranes including during at least part of a permeation step. The sorbent particles are present in the mixed liquor and contact the membranes. Bioaugmentation products may be immobilized on PAC or other carriers and then added to an MBR or other bioreactors.

Abstract: A hollow fiber membrane element may be used in a pressure vessel similar to those used with spiral wound elements, optionally as a replacement for a spiral wound element. A connecting sleeve is used to connect the insides of adjacent elements to each other or to one or more fittings in communication with the outside of the pressure vessel. The element has hollow fiber membranes suspended between two potting heads spaced apart by a cross flow tube that is open at the outside faces of both potting heads. The potting heads are each adapted to slide into an end of a connecting sleeve. A module has one or more hollow fiber elements located inside of a pressure vessel. At least one port is provided in communication between the outsides of the one or more elements and the outside of the vessel. An aerator may be provided on the bottom of the vessel.

Abstract: A hollow fiber membrane element may be used in a pressure vessel similar to those used with spiral wound elements, optionally as a replacement for a spiral wound element. A connecting sleeve is used to connect the insides of adjacent elements to each other or to one or more fittings in communication with the outside of the pressure vessel. The element has hollow fiber membranes suspended between two potting heads spaced apart by a cross flow tube that is open at the outside faces of both potting heads. The potting heads are each adapted to slide into an end of a connecting sleeve. A module has one or more hollow fiber elements located inside of a pressure vessel. At least one port is provided in communication between the outsides of the one or more elements and the outside of the vessel. An aerator may be provided on the bottom of the vessel.

Abstract: A filtration process has permeation periods and deconcentration periods. The length of the permeation period or periods between backwashes is chosen, or controlled, to allow the system to reach a TMP and flux value at which the system is operating near its mechanical limits.