An apparatus and method for filtering a fluid is provided. The apparatus includes a filtration unit having an inlet and hollow fiber membranes. The hollow fiber membranes are each formed from an elongated tube having an exterior surface and an interior surface. The hollow fiber membranes are configured to separate the filtration unit into a permeate side that allows permeate to exit the filtration unit through a permeate outlet and a retentate side that allows retentate to exit the filtration unit through a retentate outlet. The hollow fiber membranes include a coating linked to the exterior surface or interior surface of the hollow fiber membranes. The coating includes a poly electrolyte electrostatically coupled to the charged exterior surface or the charged interior surface.

A water purification filter element is provided. The water purification filter element may include a filter bottle, a filter material, an end cover, and a water self-stopping and passing structure.

A raw water channel spacer capable of suppressing formation of a concentration polarization layer in a region in the vicinity of a separation membrane in a raw water channel, and a spiral wound membrane element including the same are provided. A raw water channel spacer is formed by superposing a first yarn row and a second yarn row, and includes alternately a first mesh structure having a configuration in which first rectangular meshes formed of the yarn rows are continuous in an extending direction of the second yarn row, and a second mesh structure having a configuration in which meshes are continuous in the extending direction of the second yarn row such that an interval in the second yarn row is smaller than an interval of the second yarn row forming the first mesh structure.

Provided is a feed spacer having a three-layer structure, in which a set forming the feed spacer is formed in a three-layer structure, so that the set, which is in contact with a reverse osmosis membrane, convects raw water to a center of the structure of the feed spacer and a laminar flow velocity gradient is generated at the center to decrease a polarization phenomenon of a reverse osmosis filter module and minimize pressure loss, and a reverse osmosis membrane filter module including the feed spacer.

Provided is a feed spacer having a three-layer structure, in which a set forming the feed spacer is formed in a three-layer structure, so that the set, which is in contact with a reverse osmosis membrane, convects raw water to a center of the structure of the feed spacer and a laminar flow velocity gradient is generated at the center to decrease a polarization phenomenon of a reverse osmosis filter module and minimize pressure loss, and a reverse osmosis membrane filter module including the feed spacer.

There is provided a retrofit control module that is connectable to various types of reverse osmosis systems, and a method of using the same. The retrofit control module includes a controller, the controller being located within a housing. The controller includes a first communication interface, the first communication interface being connectable to the reverse osmosis system, a processing unit and a memory connected to the processing unit. The processing unit is configured for receiving at least one parameter of the reverse osmosis system, comparing the at least one parameter of the reverse osmosis system with a predetermined threshold and in response to the at least one parameter of the reverse osmosis system being above the predetermined threshold: transmitting a control parameter to the reverse osmosis system, the control parameter causing the reverse osmosis system to control at least one component of the reverse osmosis system.

There is provided a retrofit control module that is connectable to various types of reverse osmosis systems, and a method of using the same. The retrofit control module includes a controller, the controller being located within a housing. The controller includes a first communication interface, the first communication interface being connectable to the reverse osmosis system, a processing unit and a memory connected to the processing unit. The processing unit is configured for receiving at least one parameter of the reverse osmosis system, comparing the at least one parameter of the reverse osmosis system with a predetermined threshold and in response to the at least one parameter of the reverse osmosis system being above the predetermined threshold: transmitting a control parameter to the reverse osmosis system, the control parameter causing the reverse osmosis system to control at least one component of the reverse osmosis system.

A method of desalinating water, including the steps of when electricity costs between a first predetermined price and a second predetermined price, fill water is pumped into a reverse osmosis desalination unit to yield desalinated permeate and saltwater having a first salinity, when electricity costs less than the first predetermined price, fill water is pumped into a reverse osmosis desalination unit to yield desalinated permeate and saltwater having a second salinity, and when electricity costs greater than the second predetermined price, pure water is flowed into a reverse osmosis unit to yield pressurized saltwater which is run through a turbine to generate electricity. The first salinity is lower than the second salinity.

A method of desalinating water, including the steps of when electricity costs between a first predetermined price and a second predetermined price, fill water is pumped into a reverse osmosis desalination unit to yield desalinated permeate and saltwater having a first salinity, when electricity costs less than the first predetermined price, fill water is pumped into a reverse osmosis desalination unit to yield desalinated permeate and saltwater having a second salinity, and when electricity costs greater than the second predetermined price, pure water is flowed into a reverse osmosis unit to yield pressurized saltwater which is run through a turbine to generate electricity. The first salinity is lower than the second salinity.

An online cleaning system for micro-polluted nanofiltration membranes uses forward osmosis, and a process of the online cleaning system, and relates to the field of water treatment membrane separation technique. The online cleaning system includes a nanofiltration raw water tank, a nanofiltration membrane assembly, a pure water tank, a forward osmosis feed solution tank, a forward osmosis draw solution tank, a first saline water tank, a second saline water tank and a water bath temperature control device. Compared with convention techniques, some embodiments include efficient cleaning of the nanofiltration membranes that is realized by using forward osmosis as a nanofiltration membrane cleaning system, and cyclic regeneration of the nanofiltration membranes can be realized, so that the purposes of removing dissolved organic matters in micro-polluted raw water, reducing hardness of calcium and magnesium and prolonging the service life can be achieved.