A membrane separation pretreatment apparatus including a membrane separation unit and a first underwater plasma discharge unit disposed in front of the membrane separation unit is provided. The membrane separation pretreatment apparatus includes a membrane separation unit configured to remove particulate matter contained in raw water, and a first underwater plasma discharge unit disposed in front of the membrane separation unit and configured to cause a portion of the raw water to be introduced into the membrane separation unit to perform underwater plasma discharging.

A device for tangential flow filtration includes a filter unit having first and second fluid openings, a filter element and a permeate opening, a first flow connection to connect the first fluid opening to a reservoir, a second flow connection to connect the second fluid opening to the reservoir, a first centrifugal pump in the first flow connection to convey the fluid from the reservoir to the filter unit, a first controller to actuate the first centrifugal pump, the filter unit designed such that the fluid for tangential flow filtration is capable of flowing substantially parallel to the filter element, a second centrifugal pump in the second flow connection, with which a counter-pressure is capable of being generated at the second fluid opening, and a second controller to actuate the second centrifugal pump.

An apparatus includes a filtration skid configured to generate a filtrate through at least one of microfiltration and ultrafiltration. The apparatus further includes a desalination skid fluidly connected to the filtration skid. The desalination skid is configured to perform reverse osmosis desalination on the filtrate to generate a permeate, where the filtrate travels from the filtration skid to the desalination skid without traversing a storage tank. In one embodiment, the apparatus further comprises a controller, where the filtration skid and the desalination skid are integrated to provide self-adaptive operation of the filtration skid and the desalination skid in response to control by at least one of a supervisory controller and a local controller. In one embodiment, the control responds to at least one of temporal variability of feed water quality, a permeate production capacity target, and a permeate quality target.

A water treatment device includes a sub-reverse osmosis membrane device having a primary casing and a primary reverse osmosis membrane dividing the primary casing into a primary liquid passing part and a primary permeating part; a low pressure water feed pump feeding seawater to the primary liquid passing part at a pressure that is equal to or lower than an osmotic pressure of the seawater; a main reverse osmosis membrane device having a secondary casing and a secondary reverse osmosis membrane dividing an inside of the secondary casing into a secondary liquid passing part and a secondary permeating part; and a high pressure water feed pump feeding a primary treated liquid, which is a resultant product of the seawater passing through and flowing out of the primary liquid passing part, to the secondary liquid passing part at a pressure higher than an osmotic pressure of the primary treated liquid.

Membrane filtration systems can be used to purify liquid streams for downstream use. In practice, foulant can build-up on the surface of a membrane within a filtration system over time. The effectiveness of the filtration system will deteriorate if the fouling is not properly controlled. In some examples, a method of controlling membrane fouling in a pressurized membrane system involves supplying a feed stream that is predominately air mixed with water to the membrane. In other words, the feed stream a greater volume of air than water, even though it is the water being processed by the membrane. Supplying the pressurized membrane system with a feed stream that contains a greater volume of air than water can yield significantly better performance than supplying the membrane with a feed stream that contains a greater volume of water than air.

A membrane separation pretreatment apparatus including a membrane separation unit and a first underwater plasma discharge unit disposed in front of the membrane separation unit is provided. The membrane separation pretreatment apparatus includes a membrane separation unit configured to remove particulate matter contained in raw water, and a first underwater plasma discharge unit disposed in front of the membrane separation unit and configured to cause a portion of the raw water to be introduced into the membrane separation unit to perform underwater plasma discharging.

Disclosed herein are apparatuses and methods for semi-permeable membrane cleaning. In particular, a pressure retarded osmosis (PRO) process redirects raw solution and fluid streams in such a way as to cause periodic changes of the process from PRO to reverse osmosis (RO) for lifting and detaching fouling. Further disclosed is applying, at least periodically, a pulsed-flow regime in the fluid stream, thereby causing increased shearing force for enhanced evacuation of the foulant. Additionally, a backward wash may be provided by injection, for a predetermined injection time, of additional solution selected in such way that net driving pressure becomes RO opposite to normal PRO operation, thereby providing a backward flow from a first side of the membrane to a second side of the membrane, so as to lift and evacuate foulant.

A water purifier and a filter for the water purifier are provided. The water purifier includes a raw water flow path formed to bring in raw water from the outside, a purified water flow path connected to the raw water flow path for the raw water to flow in a first direction, a filter located in the purified water flow path to filter the raw water, a bypass flow path branched from the purified water flow path for the raw water to bypass the filter and connected to the purified water flow path on a downstream side of the filter in the first direction, a washing flow path branched from the bypass flow path and connected to the purified water flow path on a downstream side of the filter in the first direction, and a drain flow path connected to the filter to guide the raw water flowing into the filter to a second direction. The filter includes a raw water inlet through which raw water flowing in the first direction is introduced, a purified water outlet through which purified water filtered is released, and a drain outlet through which wash water having washed the filter is discharged.

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 valved raw liquid supply line, which is connected to a filtration unit including a liquid purification unit with an inlet and with outlets for purified liquid and drain liquid, a mixing device, a means for maintaining pressure, a means for maintaining a recirculating flow of liquid, which is located on a line supplying a mixture of raw liquid and concentrate upstream of the liquid purification unit, a recirculating line, a purified liquid line, a drain liquid line, and a control unit, which is connected to the means for maintaining pressure, pressure monitor, the raw liquid supply valve and a drain liquid discharge valve. The means for maintaining pressure is located on a raw liquid supply line upstream of the liquid mixing device. The technical result is a longer system working life, more efficient use of raw liquid, and reduced energy expenditure.