Abstract: An aeration system for a submerged membrane module has a set of aerators connected to an air blower, valves and a controller adapted to alternately provide a higher rate or air flow and a lower rate of air flow in repeated cycles. In an embodiment, the air blower, valves and controller, simultaneously provide the alternating air flow to two or more sets of aerators such that the total air flow is constant, allowing the blower to be operated at a constant speed. In another embodiment, the repeated cycles are of short duration. Transient flow conditions result in the tank water which helps avoid dead spaces and assists in agitating the membranes.

Abstract: A filtration module has at least one nanofiltration or reverse osmosis membrane. The module is used to filter water and, when optionally fitted with at least one membrane adapted to selectively reject hardness causing salts, is used to remove hardness. Methods of cleaning using acidic solutions or gaseous carbon dioxide are discussed. Cleaning methods include the steps of periodically stopping permeation, injecting an acidic solution or gaseous carbon dioxide into the feed/retentate side of the module, holding the acidic solution or gaseous carbon dioxide in the module for a selected time, and flushing the acidic solution or gaseous carbon dioxide from the feed/retentate side of the module after expiration of the selected time.

Abstract: The invention relates to a method and an apparatus for encoding images, more particularly to an encoding unit in conjunction with a library of pictorial entities and image qualifiers. The method and apparatus provide encoding an image by using a code factor table in conjunction with a set of element codes. The resulting image code allows the set pictorial elements of an image and their associated image qualifiers to be represented by a compact code uniquely representing a given configuration of pictorial elements. The use of the resulting image code facilitates the transmission and storage of images requiring only the code to be sent or stored. The invention further provides a computer readable medium comprising a program element that direct a computer to implement the encoding process.

Abstract: An apparatus to transfer gas to or from a liquid has a flexible and oxygen permeable but liquid water impermeable membrane, a flexible and gas permeable spacer, an inlet conduit, an outlet conduit and a non-rigid restraint system. When used for treating wastewater, an aerobic biofilm is cultured adjacent the planar elements, an anoxic biofilm is cultivated adjacent the aerobic biofilm and the wastewater is maintained in an anaerobic state. A first reactor for treating wastewater has an anaerobic section, a plurality of gas transfer membrane modules, and an aerobic section. A biofilm is cultivated on the surface of the gas transfer membranes in fluid communication with the anaerobic section. Biological reduction of COD, BOD, nitrogen and phosphorous are achieved. In a second reactor, phosphorous is also removed chemically in a precipitation branch.

Abstract: A user may discover and navigate among hyperlinks through the use of a keyboard. For example, a user may press a tab key to discover and navigate to a first hyperlink that is part of a hypertext document. The first hyperlink is, in response, given focus and a focus shape is drawn around the text or graphics for the hot region of the hyperlink. If the user again presses the tab key, the next hyperlink is given focus and a focus shape (i.e., an outline that surrounds the next hyperlink) is drawn around the next hyperlink. A user may also tab to a placeholder for an image in order to make a decision whether the image should be downloaded or not.

Abstract: An apparatus to transfer gas to or from a liquid has a flexible and oxygen permeable but liquid water impermeable membrane, a flexible and gas permeable spacer, an inlet conduit, an outlet conduit and a non-rigid restraint system. When used for treating wastewater, an aerobic biofilm is cultured adjacent the planar elements, an anoxic biofilm is cultivated adjacent the aerobic biofilm and the wastewater is maintained in an anaerobic state. A first reactor for treating wastewater has an anaerobic section, a plurality of gas transfer membrane modules, and an aerobic section. A biofilm is cultivated on the surface of the gas transfer membranes in fluid communication with the anaerobic section. Biological reduction of COD, BOD, nitrogen and phosphorous are achieved. In a second reactor, phosphorous is also removed chemically in a precipitation branch.

Abstract: A method of chemically cleaning normally immersed suction driven filtering membranes involves backwashing a chemical cleaner through the membranes while the tank is empty in repeated pulses in which the chemical cleaner is pumped to the membranes separated by waiting periods in which chemical cleaner is not pumped to the membranes. The duration and frequency of the pulses is preferably chosen to provide an appropriate contact time of the chemical, preferably without allowing the membranes to dry between pulses and without using excessive amounts of chemical. In other aspects, such membranes preferably used for filtering water to produce potable water in a batch process are backwashed with a chemical cleaner substantially at the same time as the tank is being drained. The chemical cleaner is optionally supplied in pulses.

Abstract: An aeration system for a submerged membrane module has a set of aerators connected to an air blower, valves and a controller adapted to alternately provide a higher rate or air flow and a lower rate of air flow in repeated cycles. In an embodiment, the air blower, valves and controller, simultaneously provide the alternating air flow to two or more sets of aerators such that the total air flow is constant, allowing the blower to be operated at a constant speed. In another embodiment, the repeated cycles are of short duration. Transient flow conditions result in the tank water which helps avoid dead spaces and assists in agitating the membranes.

Abstract: A method for stretching a hollow fibre while making a stretched filtering membrane from a precursor involves wrapping the hollow fibre around a structure and modifying the structure such that at least portions of the hollow fibre are forced to elongated. For example, the hollow fibre may be wrapped around around two or more supports and the distance between adjacent supports increased. This produces first portions of the hollow fibre stretched to a first elongation and porous to a first porosity and second portions of the hollow fibre that are not stretched or are stretched to a second elongation less than the first elongation and that remain non-porous or become porous to a second porosity which is less than the first porosity. The membrane may be made into a module with second portions of the membranes located at points where the membranes exit the potting material or at turns in loops of the fibres, if any. In various embodiments, the fibre is potted into modules before or after it is stretched.

Abstract: An apparatus to transfer gas to or from a liquid has a flexible and oxygen permeable but liquid water impermeable membrane, a flexible and gas permeable spacer, an inlet conduit, an outlet conduit and a non-rigid restraint system. When used for treating wastewater, an aerobic biofilm is cultured adjacent the planar elements, an anoxic biofilm is cultivated adjacent the aerobic biofilm and the wastewater is maintained in an anaerobic state. A first reactor for treating wastewater has an anaerobic section, a plurality of gas transfer membrane modules, and an aerobic section. A biofilm is cultivated on the surface of the gas transfer membranes in fluid communication with the anaerobic section. Biological reduction of COD, BOD, nitrogen and phosphorous are achieved. In a second reactor, phosphorous is also removed chemically in a precipitation branch.

Abstract: An aeration system for a submerged membrane module has a set of aerators connected to an air blower, valves and a controller adapted to alternately provide a higher rate of air flow and a lower rate of air flow in repeated cycles. In an embodiment, the air blower, valves and controller, simultaneously provide the alternating air flow to two or more sets of aerators such that the total air flow is constant, allowing the blower to be operated at a constant speed. In another embodiment, the repeated cycles are of short duration. Transient flow conditions result in the tank water which helps avoid dead spaces and assists in agitating the membranes.

Abstract: A process for reducing hair, trash or fibrous materials concentration in a waste water treatment system having a membrane filter in conjunction with a bioreactor comprises flowing a portion of mixed liquor through a screen in a side stream. The flow rate of the mixed liquor through the screen is about no more than the average design flow rate of the waste water treatment system. The screenings can be either treated or disposed of directly or in combination with the waste activated sludge. The openings of the screen are between about 0.10 mm and about 1.0 mm in size as can be provided by, for example, a rotary drum screen. The invention can be used to provide both screening and sludge thickening.

Abstract: An aerator for immersed filtering membranes has an aerator shell with openings for discharging bubbles from its upper surface and a shape capable of temporarily containing a volume of air in fluid communication with the openings. The shell is open to tank water below it and located so that discharged bubbles will rise through an assembly of the filtering membranes. The shell may be wholly or partially made of parts of the assemblies of filtering membranes. A supply of air is provided to the air space in the aerators alternating between a high flow rate and a low flow rate in short cycles of between about 10 seconds and 100 seconds. A filtration system has an inlet for adding substrate and an outlet for retentate are located so as to create a horizontal flow of substrate through the tank. Membrane assemblies are located within the horizontal flow of substrate. Aerators as described above are provided and operated as described above.

Abstract: An aerator for filtering membranes immersed in a tank of liquid has an upper surface having holes for discharging bubbles below the membranes, sides extending downwardly from upper surface for trapping a variable volume of air in communication with holes and an opening to the liquid in the tank below the volume of trapped air so that liquid can be displaced from or enter into the aerator as the volume of trapped air changes. A supply of air is provided to the air space in the aerators alternating between a high flow rate and a low flow rate in short cycles of between about 10 seconds and 100 seconds. Typically, there is substantially no air flow during the period of low air flow. The aerator is sized in relation to the duration and rate of air flow provided during a cycle such that either air flows through the holes throughout each cycle or such that no air flows through the holes during at least part of the cycle such that liquid in the tank may flood the aerator and wash away any accumulated solids.

Abstract: A process for operating filtering membranes submerged in a tank involves, in one aspect, periodically deconcentrating the tank by at least partially emptying and refilling the tank with fresh water while permeation continues. In another aspect, long trains of membranes modules are placed in series along a flow path in the tank. In one embodiment, constant aeration is provided to prevent tank water from by-passing the membrane modules while proving controlled mixing such that the average concentration of solids in the tank is lower than the concentration of solids in the tank near an outlet for removing retentate from the tank. In another embodiment, the membrane modules are arranged in a series of filtration zones between a feed water inlet and a retentate outlet of a tank. Permeate is withdrawn from the filtration zones by separate means associated with each filtration zone.

Abstract: A filtration module has a plurality of hollow fibre nanofiltration or reverse osmosis membranes suspended between a pair of opposed headers. The lumens of the membranes are the retentate or feed side. The membranes are arranged in groups, such as sectors of a cylinder, and form preceding or succeeding stages. A permeate collection plenum is in direct fluid communication with each stage. The stages are connected by caps typically having dividers located at the ends of the module. The module is used to filter water and, when optionally fitted with hollow fibre membranes adapted to selectively reject hardness causing salts, is used to remove hardness. Methods of cleaning using acidic solutions or gaseous carbon dioxide are discussed.

Abstract: A process for operating filtering membranes submerged in a tank involves, in one aspect, periodically deconcentrating the tank by at least partially emptying and refilling the tank with fresh water while permeation continues. In another aspect, long trains of membranes modules are placed in series along a flow path in the tank. In one embodiment, constant aeration is provided to prevent tank water from by-passing the membrane modules while proving controlled mixing such that the average concentration of solids in the tank is lower than the concentration of solids in the tank near an outlet for removing retentate from the tank. In another embodiment, the membrane modules are arranged in a series of filtration zones between a feed water inlet and a retentate outlet of a tank. Permeate is withdrawn from the filtration zones by separate means associated with each filtration zone.

Abstract: An apparatus to transfer gas to or from a liquid has a flexible and oxygen permeable but liquid water impermeable membrane, a flexible and gas permeable spacer, an inlet conduit, an outlet conduit and a non-rigid restraint system. When used for treating wastewater, an aerobic biofilm is cultured adjacent the planar elements, an anoxic biofilm is cultivated adjacent the aerobic biofilm and the wastewater is maintained in an anaerobic state. A first reactor for treating wastewater has an anaerobic section, a plurality of gas transfer membrane modules, and an aerobic section. A biofilm is cultivated on the surface of the gas transfer membranes in fluid communication with the anaerobic section. Biological reduction of COD, BOD, nitrogen and phosphorous are achieved. In a second reactor, phosphorous is also removed chemically in a precipitation branch.

Abstract: A method of chemically cleaning normally immersed suction driven filtering membranes involves backwashing a chemical cleaner through the membranes while the tank is empty in repeated pulses in which the chemical cleaner is pumped to the membranes separated by waiting periods in which chemical cleaner is not pumped to the membranes. The duration and frequency of the pulses is preferably chosen to provide an appropriate contact time of the chemical, preferably without allowing the membranes to dry between pulses and without using excessive amounts of chemical. In other aspects, such membranes preferably used for filtering water to produce potable water in a batch process are backwashed with a chemical cleaner substantially at the same time as the tank is being drained. The chemical cleaner is optionally supplied in pulses.

Abstract: An improvement to an outside/in hollow fiber membrane filtration system includes a source of suction on the lumens of the membranes or pressure on the outside of the membranes operable without producing permeate and an air collector to collect any air that passes from the outside of the membranes to their lumens during an integrity test. A method for testing the integrity of filtering membranes involves exposing a first side of the membranes to air while a second side of the membranes remains exposed to water. A transmembrane pressure forces air through defects of concern in the membranes. Air that passes through a set of membranes is collected and its amount measured and compared to an acceptable amount of air to indicate whether there is a defect in the set of membranes. Preferably, air is collected individually from a plurality of membrane units in a filtration train and the amounts so collected compared to indicate if one of the membrane units is defective.