A method of filtering a fluid with components includes providing an alternating pressure. The alternating pressure yields an oscillating transmembrane pressure through volume and pressure variations within a filtration chamber while sealing the filtration chamber. A separation surface can be housed in the filtration chamber wherein an influent is introduced. Components can be concentrated on the separation surface, effectively removing some or all of them from the fluid. To flush the filtration chamber and separation surface, a backwash fluid and components can be introduced and removed from the filtration chamber. While both the components are being concentrated and backwashed, the system can maintain the oscillating transmembrane pressure and varying volume and pressure relative to the separation surface.

A filtration system can comprise a pressure pump configured to apply a pressure on fluid flowing between a first chamber and a second chamber. The filtration system can also comprise a flow sensor configured to determine at least one parameter associated with fluid flowing across a membrane deposited between the first chamber and a second chamber. The filtration system can comprise a pressure sensor configured to determine pressure readings of the fluid flowing from the first chamber to the second chamber. The filtration system can comprise a filtration management system configured to cause the pressure pump to apply a constant pressure on fluid flowing across the membrane for a first predetermined time based on the pressure reading. The filtration management system can be configured to cause the pressure pump to reverse the fluid flow across the membrane.

A device for measuring the membrane fouling index which can measure the modified fouling index (MFI) and the silt density index (SDI) at the same time and quantify the degree of membrane fouling caused by various kinds of membrane fouling materials, such as particulate materials, colloids, organic matters, and so on, in a short period of time.

Methods of detecting, quantifying and/or characterizing the fouling of a device from a combination of pressure and spectroscopic data are provided. The device can be any device containing components susceptible to fouling. Components can include membranes, pipes, or reactors. Suitable devices include membrane devices, heat exchangers, and chemical or bio-reactors. Membrane devices can include, for example, microfiltration devices, ultrafiltration devices, nanofiltration devices, reverse osmosis, forward osmosis, osmosis, reverse electrodialysis, electro-deionisation or membrane distillation devices. The methods can be applied to any type of membrane, including tubular, spiral, hollow fiber, flat sheet, and capillary membranes. The spectroscopic characterization can include measuring one or more of the absorption, fluorescence, or raman spectroscopic data of one or more foulants. The methods can allow for the early detection and/or characterization of fouling. The characterization can include determining the specific foulant(s) or type of foulant(s) present. The characterization of fouling can allow for the selection of an appropriate de-fouling method and timing.

According to the present invention, since a pretreatment mechanism can be operated while inhibiting the pretreated water from fluctuating in pressure, a fresh-water production apparatus is obtained in which the desalting mechanism can be stably operated. Furthermore, the period of water supply or flushing in the step of washing the pretreatment mechanism can be shortened, and the load on the lines where washing is not being performed is hence reduced. Consequently, a fresh-water production apparatus is obtained in which the pretreatment mechanism can be operated while inhibiting the pretreatment membranes from being fouled.

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. The blood filter includes a plurality of hollow fiber membranes. During the filter cleaning sequence, a fluid mixture is formed by mixing air with a blood-compatible and physiologically safe fluid. Also during the filter cleaning sequence, the fluid mixture is transferred across insides and/or outsides of the plurality of hollow fiber membranes at least one time. The use of the fluid mixture enables the filter cleaning sequence to be performed during the blood treatment.

A filtration system can comprise a pressure pump configured to apply a pressure on fluid flowing between a first chamber and a second chamber. The filtration system can also comprise a flow sensor configured to determine at least one parameter associated with fluid flowing across a membrane deposited between the first chamber and a second chamber. The filtration system can comprise a pressure sensor configured to determine pressure readings of the fluid flowing from the first chamber to the second chamber. The filtration system can comprise a filtration management system configured to cause the pressure pump to apply a constant pressure on fluid flowing across the membrane for a first predetermined time based on the pressure reading. The filtration management system can be configured to cause the pressure pump to reverse the fluid flow across the membrane based on the at least one parameter for a second predetermined time.

An integrated system comprising a closed circuit desalination (CCD) unit with membrane cleaning (MC) means wherein the latter are activated briefly (8 minute) on a frequent basis, once a day or several days, for removal of fouling and/or scaling deposits off membrane surfaces created during the elapsed time interval and thereby, avoiding their accumulation and the need of CIP. MC proceeds in a tie-line sequence with different reagents solution in permeate known to affect the removal of common fouling and/or scaling constituents from membrane surfaces such as organic and/or bioorganic substances and/or inorganic scaling constituents including silica and polymerized silica coatings with either metal hydroxides or organic substances. Removal of silica containing deposits from membrane surfaces proceeds by a brief exposure to diluted hydrofluoric acid solution in permeate in the absence of interfering metal ions (e.g., Ca). The MC sequence incorporate both reverse osmosis (RO) and direct osmosis (DO) principles, the former to enable an effective contact of the cleaning reagents with membrane surfaces and the latter for inside-out backwash of semi-permeable membranes with permeate.

The fully computerized inventive system should enables a near perfect removal of all fouling and/or scaling constituents off membrane surfaces at an early stage on a regular basis before their accumulation and thereby, preventing the need for CIP and avoiding irreversible damage membranes as result of accumulation of irremovable fouling constituents.

This membrane separation device includes: an organic substance concentration measurement means which measures the organic substance concentration in the treatment target water; a pressure measurement unit which measures a transmembrane pressure of the separation membrane; transmembrane pressure increase speed comparing means which compares a transmembrane pressure increase speed selected on the basis of the value of the organic substance concentration measured by the organic substance concentration measurement means, with a transmembrane pressure increase speed calculated from the transmembrane pressure measured by the pressure measurement unit; and a control unit which controls the membrane surface aeration flow amount of the membrane surface aeration device, wherein the control unit changes the membrane surface aeration flow amount on the basis of the difference between the transmembrane pressure increase speeds, obtained by the transmembrane pressure increase speed comparing means.

A method for managing an operation of a reverse osmosis membrane device, includes managing the operation of the reverse osmosis membrane device based on an aluminum ion concentration and/or an iron ion concentration of a feed water and/or a concentrated water of the reverse osmosis membrane device. Any one or more of suitability of a raw water as the feed water, a water temperature of the feed water, a concentration ratio (recovery rate), a pressure (feed water supply pressure, concentrated water pressure, or treated water pressure of the reverse osmosis membrane), an amount of the concentrated water, a continuous operation period, a washing time, a wash frequency, and a timing of replacement of the reverse osmosis membrane are managed based on the aluminum ion concentration and/or the iron ion concentration of the feed water and/or the concentrated water.