A water treatment system including: a reverse osmosis membrane device A for treating a water to be treated; a reverse osmosis membrane device E for treating permeated water from device A; a reverse osmosis membrane device B for treating concentrated water from device A or E; a reverse osmosis membrane device C for treating concentrated water from device E or A; and each of water flow lines through which the concentrated water and permeated water from devices A to E respectively flow downstream, wherein the connections of each of the water flow lines are switchable so that while the concentrated water from device E flows to device B to wash device B, the concentrated water from device A is treatable by device C, and while the concentrated water from device E flows to device C to wash device C, the concentrated water from device A is treatable by device B.

The present invention is a filtration system and a method for cleaning a filtration system. The filtration system comprising a hydraulic circuit Cp recycling the permeate stream to the feed side of the membrane and/or a hydraulic circuit Cr recycling the retentate stream to the feed side of said membrane. The method injects an amount of a chemical product into the filtration system in the hydraulic circuit Cp or in the hydraulic circuit Cr or upstream of the cross-flow filtration membrane, setting the proportion of recycled permeate stream or recycled retentate stream collected in the hydraulic circuit Cp and/or Cr to enable the recycling of a significant amount of unreacted chemical product having passed through the cross-flow filtration membrane to the feed side of said cross-flow filtration membrane.

A biofouling/biofilm removal system includes a filtration module configured to separate a permeate from a feed; a first inert electrode placed at an inlet of the filtration module; a second inert electrode placed at an outlet of the filtration module; and a power source configured to apply a current between the first and second electrodes. The inlet is configured to receive the feed and the outlet is configured to discard a concentrate, and the current applied between the first and second electrodes initiates electrochemical reactions inside the feed and along a biofilm formed in the filtration module, but not into the permeate.

Multiple chemical dosing levels of differing chemical dosages are set. When control is initiated, chemical dosing is started at the level with the highest chemical dosage. Each time a sampling period S passes, the rate of increase in the pressure difference of an RO system is compared with a threshold value A. When the rate of increase is at or below the threshold value A, the chemical dosage is reduced to the level that is one step lower. When the rate of increase is greater than the threshold value A, the chemical dosage is increased to the level that is one step higher.

The present disclosure is directed to filtering technologies that combine elements of continuous and batch NF/RO based on the constraints of the end-user facility to achieve a target balance between, for instance, recovery and power consumption, and to reduce long term operating cost of a plant. A method for extending batch operation into a second induction period with antiscalant injection is also disclosed herein, with the second induction period allowing for yet higher water recovery.

Biocide can be controllably added to a feed stream for a membrane. The membrane can separate the feed stream into a purified permeate stream and a concentrate stream containing contaminants from the feed stream. In some examples, a charge neutral biocide is introduced into the feed stream at a first addition rate. The concentration of the charge neutral biocide in the permeate stream is measured to provide a measured concentration of the charge neutral biocide in the permeate stream. The addition rate of the charge neutral biocide can be adjusted based on the measured concentration of the charge neutral biocide in the permeate stream to introduce charge neutral biocide into the feed stream at a second addition rate different than the first addition rate.

The present invention relates to a computer-readable recording medium having recorded thereon a clogging location determination program for a separation membrane module, in which, in order to determine a clogging location of a separation membrane module in a fresh water generation system for obtaining treated water by filtrating water to be treated by a separation membrane module having a separation membrane, a computer is caused to function as a clogging location determination means for determining a clogging location of the separation membrane module from a resistance in a lower part of the separation membrane module, a filtration resistance of a hollow-fiber membrane, and a resistance in an upper part of the separation membrane module.

Provided is a gas separation device configured to separate a non-hydrocarbon gas from a feed gas containing the non-hydrocarbon gas through use of a gas separation membrane, in which a decrease in operating rate can be suppressed, and economic efficiency is satisfactory. A first membrane module (1) and a second membrane module (2) are arranged in parallel to each other with respect to supply lines for a feed gas. Gas lines for regeneration (14, 15) ((24, 25)), which are branched from a permeate gas line (13) ((23)) of the membrane module (1) ((2)), and which are joined to a feed gas line (21) ((11)) configured to supply the feed gas to the membrane module (2) ((1)), are provided. Under a state in which the feed gas is supplied to the membrane module (1), a permeate gas through the membrane module (1) is supplied, as a gas for regeneration, to the membrane module (2) through the gas lines for regeneration (14, 15). In this case, the membrane module (2) is brought into a non-operation state, and the membrane module (2) is regenerated.

A method includes measuring, by a flow sensor (70), a flow rate of a permeate fluid (48) flowing through a filter (20) of a membrane filtration system (12). Further, the method includes receiving, by a control unit (86), the measured flow rate of the permeate fluid (48) and determining, by the control unit (86), a first flux rate of the filter (20) based on the measured flow rate of the permeate fluid (48). Furthermore, the method includes comparing, by the control unit (86), the determined first flux rate with a first predetermined flux rate. Additionally, the method includes operating the membrane filtration system (12), by the control unit (86), in a normal mode or a flux tolerant mode based on the comparison of the determined first flux rate with the first predetermined flux rate. The flux tolerant mode of the membrane filtration system (12) is further based on a determined normalized water permeability value of the filter (20).

A method includes inducing a first quantity of a feed fluid (28) to flow along a first direction (72) from a bioreactor (12) to a tangential flow filter (16) to separate the first quantity of the feed fluid (28) into a permeate fluid (42) and a retentate fluid (48). Further, the control unit (66) is operated to control at least one feed flow control device (24, 26) to inhibit the flow of first quantity of the feed fluid (28). Furthermore, the control unit (66) is operated to control the at least one feed flow control device (24, 26) to direct at least one of further flow of a second quantity of the feed fluid (28) from the bioreactor (12), a portion of the permeate fluid (42), and a portion of a nutrient fluid, along a second direction (74) opposite to the first direction (72) via the tangential flow filter (16).