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 An exhaust gas is withdrawn from the gas transfer membrane and used to produce bubbles from an aerator immersed in the water.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 An exhaust gas is withdrawn from the gas transfer membrane and used to produce bubbles from an aerator immersed in the water.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 cord for supporting a biofilm has a plurality of yarns. At least one of the yarns comprises a plurality of hollow fiber gas transfer membranes. At least one of the yarns extends along the length of the cord generally in the shape of a spiral. Optionally, one or more of the yarns may comprise one or more reinforcing filaments. In some examples, a reinforcing yarn is wrapped around a core. A module may be made by potting a plurality of the cords in at least one header. A reactor may be made and operated by placing the module in a tank fed with water to be treated and supplying a gas to the module. In use, a biofilm covers the cords to form a membrane biofilm assembly.

Abstract: A cord for supporting a biofilm has a plurality of yarns. At least one of the yarns comprises a plurality of hollow fiber gas transfer membranes. At least one of the yarns extends along the length of the cord generally in the shape of a spiral. Optionally, one or more of the yarns may comprise one or more reinforcing filaments. In some examples, a reinforcing yarn is wrapped around a core. A module may be made by potting a plurality of the cords in at least one header. A reactor may be made and operated by placing the module in a tank fed with water to be treated and supplying a gas to the module. In use, a biofilm covers the cords to form a membrane biofilm assembly.

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: This specification describes a membrane aerated biofilm media and reactor (MABR) having a discontinuous layer of a porous material applied to the outer surface of a gas-transfer membrane. The porous material may have a void fraction of 50% or more. The porous material may have a thickness of up to about 500 microns and a pattern on the same order of magnitude as its thickness. The media may be used to carry on a deammonification reaction. In use, ammonia oxidizing bacteria (AOB) and annamox bacteria grown in or on the media, with the annamox bacteria located primarily in the porous material. The supply of oxygen through the gas-transfer membrane is limited to suppress the growth of nitrite oxidizing bacteria (NOB). Excess biofilm is removed, for example by coarse bubble scouring. The media may be placed in an anoxic zone of an activated sludge plant, which may be upstream of an aerobic zone.

Abstract: A cord for supporting a biofilm has a plurality of yarns. At least one of the yarns comprises a plurality of hollow fiber gas transfer membranes. At least one of the yarns extends along the length of the cord generally in the shape of a spiral. Optionally, one or more of the yarns may comprise one or more reinforcing filaments. In some examples, a reinforcing yarn is wrapped around a core. A module may be made by potting a plurality of the cords in at least one header. A reactor may be made and operated by placing the module in a tank fed with water to be treated and supplying a gas to the module. In use, a biofilm covers the cords to form a membrane biofilm assembly.

Abstract: A cord for supporting a biofilm has a plurality of yarns. At least one of the yarns comprises a plurality of hollow fiber gas transfer membranes. At least one of the yarns extends along the length of the cord generally in the shape of a spiral. Optionally, one or more of the yarns may comprise one or more reinforcing filaments. In some examples, a reinforcing yarn is wrapped around a core. A module may be made by potting a plurality of the cords in at least one header. A reactor may be made and operated by placing the module in a tank fed with water to be treated and supplying a gas to the module. In use, a biofilm covers the cords to form a membrane biofilm assembly.

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 bioreactor has a biofilm that receives a gas through a supporting membrane and another biofilm attached to an inert support. The first biofilm is aerated through the membrane and provides nitrification. The other biofilm has an anoxic or anaerobic zone and provides denitrification. A module useful in the bioreactor has cords potted in at least one potting head. Optionally, some or all of the cords have a gas transfer membrane. The module may provide inert supports, active gas transfer supports or a combination of both types of support. Multiple modules may be assembled together into a cassette, the cassette providing inert supports, active supports or a combination. The module or cassette may have an aerator for mixing or biofilm control.

Abstract: A conventional activated sludge wastewater treatment plant is upgraded by adding one or more of a membrane filtration unit, a membrane aerated biofilm reactor (MABR) unit, and a screen. The membrane filtration unit is added between a process tank and the secondary clarifier. The membrane filtration unit extracts treated effluent at a rate up to 25% of the influent flow rate. The plant is not converted into a membrane bioreactor (MBR) since the MLSS concentration is still less than 4,000 mg/L. The membrane-aerated biofilm reactor (MABR) unit is added to a process tank of the plant and provides attached growth biological treatment. The screen extracts solids from water flowing to the process tanks. When optionally used in combination, the added units and processes increase the capacity of the primary separation, biological processing and secondary separation functions of the plant. The influent flow rate may be increased.

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: 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 bioreactor has a biofilm that receives a gas through a supporting membrane and another biofilm attached to an inert support. The first biofilm is aerated through the membrane and provides nitrification. The other biofilm has an anoxic or anaerobic zone and provides denitrification. A module useful in the bioreactor has cords potted in at least one potting head. Optionally, some or all of the cords have a gas transfer membrane. The module may provide inert supports, active gas transfer supports or a combination of both types of support. Multiple modules may be assembled together into a cassette, the cassette providing inert supports, active supports or a combination. The module or cassette may have an aerator for mixing or biofilm control.

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: An immersed membrane system or process may use measured or calculated process information to optimize one or more process operating parameters to improve performance or reduce operating costs. An on-line process control system or method may use the resistance in series method in operating an immersed membrane water treatment system. A process control system or process may consider resistance values and adjust operational parameters such as membrane aeration frequency factor, membrane aeration flow, permeate flux, permeation duration, backwash flow and duration, relaxation duration or maintenance or recovery chemical cleaning frequencies in order to reduce the operational costs related to membrane fouling removal.