Provided is a method for operating an RO-membrane treatment system that includes an energy recovery device that recovers energy from the concentrate of an RO-membrane device and the RO-membrane treatment system that reduce the occurrence of biofouling in not only the RO-membrane device but also the energy recovery device in order to increase the energy efficiency of the entire system and operate the RO-membrane treatment system with consistency. The method includes adding at least one slime-control agent selected from a combined-chlorine slime-control agent and a stabilized-bromine slime-control agent to water that is to be treated with the reverse-osmosis-membrane device such that a residual halogen concentration in the concentrate that is to be introduced into the energy recovery device is 0.1 to 10000 mg/L as total chlorine.

A reverse osmosis system and method includes a feed pump pressurizing a feed stream, a first and second membrane array that generates permeate and brine streams. A first turbocharger uses first energy from the second brine stream to pressurize the first brine stream. A first and second auxiliary and bypass valves are associated with the first and second turbocharger. A second turbocharger uses second energy from the second brine stream to increase a second pressure of the feed stream. A first flow meter generates a first flow signal for the first permeate stream. A second flow meter generates a second flow signal for of the second permeate stream. A third flow meter generates a third flow signal for the second brine stream or the feed stream. A motor drives the first turbocharger or the feed pump. A controller controls the motor in response to the flow signals.

A fluid system includes a membrane module including a first section and a second section that are separated by a semipermeable membrane, a feed pump connected to the first section, a draw pump connected to the second section, a load connected to the second section, a flush valve, and an electronic control unit (ECU) configured to control one or more of the feed pump, the draw pump, the flush valve, and the load. The ECU may be configured to control the feed pump, the draw pump, the flush valve, and/or the load according based on or according to net power generation.

A reverse osmosis system and method of operating the same includes a membrane housing comprising a reverse osmosis membrane therein. The membrane housing has a feed fluid input, a brine outlet and a permeate outlet; The system further includes a charge pump, a plurality of valves and a tank having a volume comprising a movable partition dividing the volume into a first volume and a second volume. The plurality of valves selectively couples the charge pump to the first volume or the second volume and the brine outlet to the second volume or the first volume respectively.

A reverse osmosis system includes a wheel formed of a hollow central hub, radial tubes fluidly connected to the central hub, semi-permeable membranes provided in each radial tube, a permeate outlet tube, and a concentrate outlet tube; a permeate collection tank; a concentrate collection tank; and a drive mechanism. The drive mechanism rotationally drives the wheel while the source liquid is supplied to the central hub of the wheel, the rotation causing the source liquid to enter the radial tubes in radially outward directions and cause pressure increase on the source liquid in the radial tubes. The pressure increase forces the source liquid through the semi-permeable membranes to separate into permeate and concentrate, the permeate being directed to the permeate collection tank through the permeate outlet tube and the concentrate being directed to the concentrate collection tank through the concentrate outlet tube.

A reverse osmosis system and method includes a pump pressurizing a feed stream, a first and second membrane array that generates permeate and brine streams. A first energy recovery device uses first energy from the second brine stream to pressurize the first brine stream. A first and second auxiliary and bypass valves are associated with the first and second energy recovery device. A second energy recovery device uses second energy from the second brine stream to increase a second pressure of the feed stream. A first flowmeter generates a first flow signal for the first permeate stream. A second flowmeter generates a second flow signal for of the second permeate stream. A third flowmeter generates a third flow signal for the second brine stream. A motor drives the first energy recovery device. A controller controls the in response to the flow signals.

An object of the present invention is to provide a desalination apparatus in which a high pressure pump can be operated at a high efficient operation point even when temperature, salt concentration or the like of water to be treated vary. The desalination apparatus includes a high pressure pump which is provided in a first flow path and supplies raw water to a first module at high pressure to apply reverse osmotic pressure to a first module and a second module, a third flow path for supplying second concentrated water after separation in the second module to upstream of the high pressure pump in the first flow path, and a fourth flow path for supplying a portion of the first concentrated water after separation in the first module to upstream of the high pressure pump in the first flow path.

An example water purification system for purifying high concentration feed solutions includes a high rejection forward osmosis module, one or more low rejection modules, and a high rejection reverse osmosis module. The low rejection modules may have different rejection levels. The system may be pressurized by one or more pumps. One or more of the low rejection modules may include one or more nanofiltration (NF) membranes. The draw solution may comprise a monovalent salt, a multivalent salt, or a combination of both.

An apparatus, system and method to purify water is disclosed. Pumps and energy recovery devices for taking water from an intake, filtering the water to remove solid contaminates before running the filtered water through the reverse osmosis system to the discharge device and purified water lines are described. The system may comprise a control panel that controls the plurality of filters, plurality of reverse osmosis membranes, purified water line and effluent discharge device, to achieve favorable water purification. A method that utilizes the apparatus and/or system is described herein.

The reverse osmosis centrifuge converts rotational energy into fluid velocity and conserves the energy placed into the concentrate. As concentrate travels back towards the center of the reverse osmosis centrifuge, the velocity of the fluid is converted into rotational force, thus conserving energy. To accomplish this, the reverse osmosis centrifuge includes a stationary cylindrical housing having a vacuum chamber and a vacuum pump for generating vacuum pressure in the vacuum chamber, a driveshaft coupled to a membrane cylinder rotatable within the stationary cylindrical housing, the membrane cylinder having a plurality of vertical desalination membranes, and an energy recovery turbine. The reverse osmosis centrifuge can be placed on the concentrate or waste stream outlet of a desalination or reverse osmosis facility to increase freshwater production. Through using the methods described above, plant water production can be increased up to 40%, which in turn has a dramatic effect on plant profitability.