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/m.sup.2/h. The membranes are dosed with chlorine or another oxidant, preferably at 700 minutes*mg/L as Cl.sub.2 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.

An example water purification system for purifying high concentration feed solutions includes a high rejection forward osmosis module, one or more low rejection modules, and a high rejection reverse osmosis module. The low rejection modules may have different rejection levels. The system may be pressurized by one or more pumps. One or more of the low rejection modules may include one or more nanofiltration (NF) membranes. The draw solution may comprise a monovalent salt, a multivalent salt, or a combination of both.

An apparatus for extracting a material from a liquid includes a concentration stage having a tangential flow filter, a first path from the tangential flow filter, and a second path from the tangential flow filter. Under this configuration, the concentration stage accepts an initial liquid volume. A first liquid not having material collected by the tangential flow filter is passed along the first path, and concentrated liquid having material therein, which is entrapped by the filter, is directed to the second path. The apparatus also includes an aerosolizing stage coupled to the concentration stage that converts the concentrated liquid into an aerosol and a drying stage that dries the aerosol such that material extracted from the aerosol onto a material substrate.

An apparatus for extracting a material from a liquid includes a concentration stage having a tangential flow filter, a first path from the tangential flow filter, and a second path from the tangential flow filter. Under this configuration, the concentration stage accepts an initial liquid volume. A first liquid not having material collected by the tangential flow filter is passed along the first path, and concentrated liquid having material therein, which is entrapped by the filter, is directed to the second path. The apparatus also includes an aerosolizing stage coupled to the concentration stage that converts the concentrated liquid into an aerosol and a drying stage that dries the aerosol such that material extracted from the aerosol onto a material substrate.

A method for process a chemical liquid is provided. The method includes at least providing a system having at least one filtration medium, treatment the system with a treatment liquid having a content of iron (Fe) and calcium (Ca) of about 10 ppb or less, and processing a chemical liquid using an apparatus having the system configured therein after the treatment process.

An automated modular filtration system, particularly for low volume tangential flow filtration processes, comprises a plurality of filtration modules formed as separate assemblies and at least one control unit for jointly controlling filtration processes of individual filtration units. Each filtration module contains at least one individual filtration unit for executing a filtration process independent of the other filtration units, first input ports for receiving a first type of fluids, second input ports for receiving a second type of fluids, and exit ports for outputting unused system fluids. First type fluids are process fluids are specific to the filtration processes executed in individual filtration units. Second type fluids are system fluids not specific to filtration processes executed in the individual filtration units. The second input and exit ports establish inter-module connections so system fluids can be forwarded from one filtration module to an adjacent filtration module of the filtration system.

An example water purification system for purifying high concentration feed solutions includes a high rejection forward osmosis module, one or more low rejection modules, and a high rejection reverse osmosis module. The low rejection modules may have different rejection levels. The system may be pressurized by one or more pumps. One or more of the low rejection modules may include one or more nanofiltration (NF) membranes. The draw solution may comprise a monovalent salt, a multivalent salt, or a combination of both.

An apparatus and method for cleaning and restoring air separation modules (ASMs). The present invention cleans and restores ASMs that comprise a gas permeable fiber module that uses a fiber composition in the polyimide hollow fiber family. The present invention removes contaminants, such as fuel, from an ASM by blowing air at environmental temperature into the ASM, and then restores the ASM by blowing hot air into the ASM.

A water treatment chemical for membranes, which contains a polymer compound having a carboxyl group and a sulfo group, preferably a polymer compound represented by formula (1). A membrane treatment method wherein this water treatment chemical for membranes is added to membrane feed water when water to be treated, which contains an organic compound having a phenolic hydroxy group, is subjected to a membrane separation treatment. ##STR00001## In the formula, m and n represent molar percentages of respective structural units; (m+n) is 90-100%; and R represents an anionic group containing a sulfo group.

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.