In a waste water treatment method using membrane separation-activated sludge, when, during filtration while supplying air using an immersion-type membrane separation unit loaded with multiple flexible membranes, the filtration differential pressure of the membranes at a set filtration flow rate exceeds a specified value P2 with respect to the filtration differential pressure P1 of the initial period of operation, membrane filtration is continued with air supply stopped until the filtration differential pressure P3 becomes P3P1+20 [kPa]. Then with the filtration flux or filtration pressure being smaller or negative compared to when filtering while supplying air, air is supplied and after the filtration differential pressure P4 during filtration reaches P4P1+5 [kPa], filtration is returned to filtration while supplying air.

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.

A detonator positioning device for use with a detonator in a perforating gun assembly is described. The detonator positioning device is configured for electrically contactably forming an electrical connection within the perforating gun housing by contact. The detonator positioning device includes a body having a first end, a second end, and a central bore extending between the first and second ends. The central bore is adapted for receiving one or more electrically contactable components of a detonator. The detonator positioning device aligns at least one of the one or more electrically contactable components to form an electrical connection with a bulkhead assembly.

A system for aerating a submerged membrane is provided. The system includes: a device for supplying compressed air; at least one orifice for aerating the submerged membrane; a pipe for feeding air from the air supplying device to the at least one aeration orifice; a first valve for opening or closing an orifice between the pipe and the surrounding air; a pressure sensor configured to measure the pressure in the pipe. The system is configured to perform at least one iteration of an operation to evacuate solid materials from the pipe, the said evacuation including at least: stopping supplying compressed air in the pipe and opening the first valve, causing reduction of the pressure in and penetration of liquid into the pipe; closing the first valve and resuming supplying compressed air in the pipe causing an increase in the pressure in and expulsion of liquid from the pipe through the at least one aeration orifice. The system is characterized in that it includes a processor configured to receive pressure measurements from the said pressure sensor that are performed during the said evacuation operation and to detect an anomaly of the aeration system on the basis of a comparison of the pressure measurements and at least one pressure threshold higher than or equal to the hydrostatic pressure of the column of liquid.

A membrane filter for submerged operation for filtering a liquid, comprising membrane elements and geyser elements for flushing the membrane elements in pulses using a gas, each membrane element having: hollow fiber membranes secured in a base element, each hollow fiber membrane having a lumen into which a liquid permeate is filterable out of the liquid, a permeate collection cavity connected to the lumens of the hollow fiber membranes for collecting the permeate from the hollow fiber membranes, a permeate outlet for discharging the permeate out of the permeate collection chamber, and a tubular housing enveloping the hollow fiber membranes of the membrane elements and penetrated by the permeate outlet, wherein the geyser elements are installed below the membrane elements, and each of the geyser elements having: a gas collection cavity and an outlet device for discharging the gas in pulses upwards out of the gas collection cavity.

A water treatment system is disclosed. The water treatment system comprises a filtration module comprising one or more ultrafiltration membrane configured to remove one or more non-PFAS contaminant from a PFAS contaminated water stream to provide a partially purified water stream containing soluble PFAS contaminants. The water treatment system also comprises a sorption module comprising one or more sorption units comprising a sorbent material, the sorption module being in fluid communication with the filtration module and downstream therefrom and configured to remove substantially all PFAS contaminants from the partially purified water stream to provide purified water that is substantially free from PFAS contamination.

Algae harvesting and cultivating systems and methods for producing high concentrations of algae product with minimal energy. In an embodiment, a dead-end filtration system and method includes at least one tank and a plurality hollow fiber membranes positioned in the at least one tank. An algae medium is pulled through the hollow fiber membranes such that a retentate and a permeate are produced.

Algae harvesting and cultivating systems and methods for producing high concentrations of algae product with minimal energy. In an embodiment, an algae harvesting method is provided for performing dead-end filtration in an algae harvesting system having at least one treatment tank defining a plurality of filtration stages including at least a first filtration stage and a second filtration stage. An algae medium is pulled through the hollow fiber membranes such that a retentate and a permeate are produced.

A purge air regulating unit for a drying device for compressed air, the purge air regulating unit being connectable to a housing in which a membrane filter, such as a bundle of hollow fiber membranes, is arranged such that a sub-flow of dried compressed air flowing out of the housing from an outlet channel can be conducted back to the hollow fiber membranes as purge air by the purge air regulating unit. A method for regulating the flow of dried compressed air flowing out of a membrane dryer back into a housing of the membrane dryer, the membrane dryer being equipped with a membrane filter, such as a bundle of hollow fiber membranes, is also provided.

In a first membrane filtration module comprises a membrane module comprising a plurality of permeable hollow membranes; a fluid distribution device adapted to removably surround at least a portion of the membranes of the membrane module, the fluid distribution device comprising a plurality of through-hole openings for distributing a fluid, and the fluid distribution device adapted to distribute a flow of fluid along a surface of the permeable hollow membranes. In a second membrane filtration device comprises a membrane module comprising a plurality of permeable hollow membranes, each of the permeable hollow membranes having a surface; and a gas distribution device: adapted to distribute gas bubbles to the surface of the permeable hollow membrane, adapted to removably surround at least a portion of the plurality of permeable hollow membranes, and defining a plurality of through openings for distributing the gas bubbles to the membranes.