[Object] To provide a method for isolating and purifying a minute useful substance. [Solution] Disclosed is a method for isolating and purifying a minute useful substance. The method includes filtering a liquid containing a minute useful substance through a hollow fiber membrane. The hollow fiber membrane has an inner diameter of 0.2 mm to 1.4 mm and a molecular weight cut-off of 100000 to 1000000. The filtering includes a first filtration process of press-fitting the liquid containing the minute useful substance from a first opening on one end side of the hollow fiber membrane and filtering the liquid to separate the liquid into a permeate and a first concentrate, and a second filtration process of press-fitting the first concentrate from a second opening on the other end side of the hollow fiber membrane and filtering the first concentrate to separate the first concentrate into a permeate and a second concentrate. A concentrate is produced in which a concentration of the minute useful substance is increased by filtration in which the first filtration process and the second filtration process are alternately performed a plurality of times at a membrane surface velocity of 0.3 m/sec to 2 m/sec.

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.

The present invention provides a membrane separation process comprising a pressurized feed of solution that is combined with a repressurized, internal circulation of a concentrated solution. This combined flow of feed solution and concentrated solution may be introduced to either end of pressurized vessels containing membranes and this direction of flow is periodically reversed. This combination of repressurized internal circulation and reversal of the direction of flow allows for manipulations of concentration gradients both along the length of membranes in the pressure vessel and concentration gradients within the boundary layers at the surface of the membranes

A method of operating a pressure-retarded osmosis plant, the plant comprising at least one osmosis element having a semi-permeable membrane, the semi-permeable membrane defining a feed side and a permeate side of the osmosis element, the method comprising, in a first mode of operation, supplying a feed stream having a relatively high concentration of solute to the feed side, supplying a permeate stream having a relatively low concentration of solute to an inlet of the permeate side, and receiving a feed outlet stream from the feed side wherein permeate has passed through the semi-permeable membrane from the permeate side to the feed side, in a second mode of operation, supplying a backwash stream having a relatively low concentration to the feed side of the osmosis element such that water passes through the semi-permeable membrane, and receiving a permeate outlet stream from an outlet of the permeate side, the method further comprising alternately performing the first mode of operation, to perform a production step, and performing the second mode of operation, to reduce fouling of the semi-permeable membrane.

A method for removing silica includes treating feedwater with Mg at a high pH, inputting treated feedwater to an optional reactor, pumping the feedwater to a ceramic membrane in a first direction, removing precipitated solids with the ceramic membrane, and removing the precipitated solids from the ceramic 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 be-comes 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 renal therapy apparatus includes a blood filter, a blood pump, a treatment fluid pump, and a control unit configured to control at least one of the blood pump or the treatment fluid pump during a filter cleaning sequence. In a first phase of the filter cleaning sequence, a first fluid including a blood-compatible and physiologically safe fluid is transferred back and forth across the insides and/or outsides of the blood filter. After the first phase, a second fluid is formed by mixing the first fluid with air. In a second phase of the filter cleaning sequence, the second fluid is transferred across the insides and/or outsides of the blood filter at least one time.

A peritoneal dialysis apparatus includes a filter and a dialysis fluid circuit in fluid communication with the filter. The peritoneal dialysis apparatus also includes a pump for pumping fresh dialysis fluid to a peritoneum of a patient via the dialysis fluid circuit and pumping used dialysis fluid from the peritoneum of the patient through the dialysis fluid circuit and the filter. The peritoneal dialysis apparatus further includes a selective air access in fluid communication with the dialysis fluid circuit and a control unit configured to control the pump during a peritoneal dialysis treatment and a filter cleaning sequence. The control unit forms a fluid mixture during a filter cleaning sequence by opening the selective air access to mix air with a physiologically safe fluid. The fluid mixture is transferred across insides and/or outsides of the filter at least one time.

The present application includes a symbiotic reverse osmosis train system for maximizing desalinated water recovery, meanwhile yielding high salinity brine suitable for osmotic power generation or commercial salt production. The trains comprise a series of cells operating in an interrelated sequential pattern within a salinity field. Each cell forms a closed hydraulic brine loop having pumping means, power recovery means and shared semipermeable membranes between adjacent cells. Used are a semipermeable Flat Sheet or Hollow Fiber Membrane in desalination and osmotic power generation of brackish, seawater and brines of 15% salinity or more. Charging each cell in the train of cells with a formulated brine having a specified ionizable inorganic salt concentration and type, without permitting mixing of the given brines among adjacent cells. Allowing the train to achieve water recovery exceeding 85% with concentrated rejected brine of 28-30% salt content.

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.