Abstract: The present invention provides a semi-batch method and a hyperfiltration system for treating a raw water. The hyperfiltration system is suitable to switch between two modes: a recirculation mode wherein the concentrate stream from hyperfiltration elements is recycled and a flush mode that sends the concentrate stream to discharge. The hyperfiltration system includes an energy recovery device suitable to recover energy from the concentrate stream during the flush mode. Liquid flows through the energy recovery device during at least a portion of said recirculation mode. Preferably the energy recovery device is an isobaric energy recovery device or a pressure exchanger.

Abstract: A method for fractionating a sulfuric acid process stream having at least 1 wt % sulfuric acid, using a treatment system comprising three filtration assemblies each having membranes that are suitable to pass less than 10% salt in a standard test such that average passage of sulfuric acid from the first and third filtration assemblies is less than 30% and average passage of sulfuric acid from second filtration assembly is more than 70%. The system produces a fraction of the stream with a pH between 4 and 10, and a second fraction that contains at least 20 weight percent of sulfuric acid.

Abstract: A water treatment system comprising a pressure vessel, vertically aligned separation elements within the vessel each having at least one porous UF or MF membrane, feed fluid passageways, a permeate fluid passageway, a concentrate removal port, and a biocontactor within the vessel that has biogrowth surfaces surrounding flow paths through the biocontactor. The flow paths have a median ratio of surface area to volume which exceeds 15 cm?1. The pressure vessel also contains a pressure plate with holes which separates the vessel into two chambers, a first chamber containing membrane elements and a second chamber that contains the biocontactor. A sealing means contacting the pressure plate prevents fluid flow between the first chamber and second chamber except through the porous membranes.

Abstract: A filtration system having: (a) a recirculation loop, (b) a pump, (c) a waste outlet, (d) a valve separating the loop from a waste outlet (d) a control device for said valve, (e) a membrane pressure vessel comprising a feed port, concentrate port and permeate port, and hyperfiltration elements in an axial direction, including an end hyperfiltration element nearest an inlet port or outlet port, (f) a flow distributor located between said end hyperfiltration element and said fluid port to provide a velocity profile with a coefficient of variation of less than 0.1 or a flow resistance of between 10 and 200 kP·sec·m?1, (g) wherein the flow distributor has a proximal surface nearest the end hyperfiltration element and a distal surface nearest said fluid port, and (h) an axial positioner that locates said distal surface at least 50% of the distance between the end hyperfiltration element and the port.

Abstract: A spiral wound filtration membrane element has a scroll face that includes at least two, concentric, axially displaced regions. At least one of those regions is sealed and at least one is unsealed. Such a membrane element can be produced by a winding process followed by a trimming or cutting step which produces the concentric, axially displaced regions. The seal can be applied before, during or after the trimming or cutting step.

Abstract: A method for fractionating a sulfuric acid process stream having at least 1 wt % sulfuric acid, using a treatment system comprising three filtration assemblies each having membranes that are suitable to pass less than 10% salt in a standard test such that average passage of sulfuric acid from the first and third filtration assemblies is less than 30% and average passage of sulfuric acid from second filtration assembly is more than 70%. The system produces a fraction of the stream with a pH between 4 and 10, and a second fraction that contains at least 20 weight percent of sulfuric acid.

Abstract: Filtration vessels containing multiple filtration elements, and devices and processes for detection of leaks within these filtration elements.

Abstract: The present invention pertains to an apparatus and method for treating a solution of high osmotic strength, especially seawater and solutions of greater than 20 bar osmotic pressure, by passing the solution through a vessel containing spiral wound reverse osmosis or nanofiltration elements. The vessel contains at least three elements in series and at least two of these elements have standard specific fluxed that differ by at least 50%. The invention allows a more even flux distribution within a filtration system to be obtained, and it may advantageously be combined with variations en element construction and feed spacers.