A method for operating a desalting device that has a first desalting device and a second desalting device, said method comprising: a normal operation step for supplying to-be-treated water to the first desalting device so as to separate the to-be-treated water into first concentrated water and first desalted water, and supplying the first concentrated water to the second desalting device so as to separate the first concentrated water into second concentrated water and second desalted water; and a recovery operation step for supplying the to-be-treated water to the first desalting device so as to separate the to-be-treated water into the first concentrated water and first permeate water, and passing dilute water having a lower concentration than the first concentrated water through the second desalting device so as to recover desalting performance of the second desalting device.

A membrane gas separator with a built-in valve along with a method of open and closing the membrane gas separator are disclosed herein. The membrane separator contains an an inlet chamber, hollow selective fibres, an outlet chamber, a central core element and a flushing space. The membrane separator contains a built-in combined valve in the outlet chamber and a the central space and a check valve at an inlet manifold. The built-in valve contains a throttling section to ensure a reduced backflow of a final product from the outlet manifold to the inner space of hollow fibres, and the sealing section to stop the flow of the flushing medium from the outlet chamber to the flushing space when no inlet medium flows through the separator. The method of opening of the membrane separator includes opening of the sealing section and subsequent opening and deactivation of the throttling section. The method of closing of the membrane separator includes closing and activation of the throttling section and closing of the sealing section.

The disclosure relates to water treatment systems that may be used to remove impurities from water, particularly systems that inserted at the point of entry of a water supply into a building.

A fluid filtration system includes a fluid storage vessel such as a bioreactor, a filter housing including a filter element disposed therein, a pump coupled between the fluid storage vessel and the filter housing, and a flow diverter disposed between the pump and the filter housing. The pump is configured to move fluid from the fluid storage vessel through the filter element, and the flow diverter is configured for selectively directing fluid received from the pump to the first or second end of the filter housing. In a first mode of operation, the flow diverter directs flow through the filter housing in a first direction, while in a second mode of operation, the flow diverter directs flow through the filter housing in a second direction opposite the first direction.

A filtration device includes a continuous first unit including a first membrane that separates a liquid into first permeated and non-permeated liquids, a first adjuster that adjusts a flow rate of the first permeated liquid to be substantially constant, and a first liquid scale that detects a liquid amount, a second unit including a second membrane that separates another liquid into second permeated and non-permeated liquids, a second adjuster that adjusts a flow rate of the second permeated liquid to be substantially constant, and a second liquid scale that detects another liquid amount, a first controller that controls the liquid amount in the first storage tank based on measurement values from continuous two first units or from the continuous first and second units, and a second controller that controls the another liquid amount based on a measurement value from the second unit.

An apparatus and a method use permeate to flush a reverse osmosis filter membrane in the same flow direction as when fluid is being filtered through the membrane. The apparatus includes a housing having a membrane positioned therein. The membrane has an interior surface and an exterior surface. The housing has an inlet port located outward of the exterior surface of the membrane and first and second outlet ports. The first outlet port is located outward of the exterior surface of the membrane and the second outlet port is located inward of the interior surface of the membrane. A first pump is used to route pressurized, untreated fluid from a fluid source through the membrane to produce permeate. A second pump is used to route permeate to a desired function while also routing some permeate at low pressure to the housing to flush the membrane.

Apparatus and method for semi-permeable membrane cleaning in particular, applying series of pulsed water stroke, made simultaneously with osmosis backward flow causing superposed membrane directional shaking and fouling detachment. Pulsed water stroke provided by water stroke generator as several momentum sharp changes in gauge pressure and induce velocity pulse of residual brine flow. The pulsed water strokes ideally induce resonance in the membrane. Osmosis backward wash may be provided either by injection for predetermined injection time, additional solution selected in such way that net driving pressure becomes opposite to normal osmotic operation thereby providing a backward flow of permeate towards to the side opposite to normal operation mode, so as to lift said foulant, or by throttling permeate exiting from the permeate enclosure, until the net driving pressure value become equal to zero, during application of precise synchronized and opposing brine and permeate pressure strokes thereby providing a plurality of quick RO-FO-RO process changes. These procedures allow a membrane to be kept continuously clean and operate at higher recovery.

A membrane filtration device includes a plurality of membrane separation units vertically disposed in multiple stages. The membrane separation unit has a primary side communicating with a backwash drainage system and a flushing-air supply system to receive supplied raw water and a secondary side communicating with a backwash-water supply system to collect permeate. The backwash-water supply system includes a backwash-water main pipe and a plurality of backwash-water branch pipes to feed the backwash water into the membrane separation units. The backwash drainage system includes a plurality of backwash-drainage branch pipes and a backwash-drainage main pipe connected in parallel to the backwash-drainage branch pipes. The flushing-air supply system includes an air main pipe for passing flushing air upward and a plurality of air branch pipes for feeding flushing air into the membrane separation units, the air branch pipes being connected in parallel to the air main pipe.

A water treatment device includes: a measure that repeats measurement of pressures on a primary side and a secondary side of a hollow fiber membrane module every minute time of three seconds or less in one or more steps of water filling, backwashing, pressure relieving, bubbling, and draining; and an estimater that estimates: abnormality of an internal state of the hollow fiber membrane module or of a peripheral device; a time required from a start to an end of the one or more steps; an effect of physical washing or chemical washing; or a future increase in an membrane differential pressure, based on a temporal transition of a measurement result of at least one of the pressures, or based on a difference in the temporal transition between a plurality of times of the step.

The present invention provides a hollow fiber membrane module that can effectively resolve the accumulation of suspended solids within the membrane module, lower running costs, and also operate stably. The present invention relates to a hollow fiber membrane molecule provided with: a cylindrical case having a first end and a second end in the direction of height; a plurality of hollow fiber membranes accommodated within the cylindrical case; and a first potting part accommodated within the cylindrical case and attaching the plurality of hollow fiber membranes together such that the end parts of the plurality of hollow membrane fibers at a first end side of the cylindrical case are open. The hollow fiber membranes are porous hollow fiber membranes having a breaking strength of 23 MPa, and the hollow membrane module has a membrane area per unit volume of 800-3700 m.sup.2/m.sup.3. The filling fraction for the hollow fiber membranes in a cross-section orthogonal to the direction of height of the cylindrical case is 25-38%.