An energy recovery system for use in a reverse osmosis system is provided. The energy recovery system has a pair of double headed pistons that reciprocate to pressurize unfiltered water into a reverse osmosis filtration unit. High pressure wastewater from the reverse osmosis filtration unit is used in conjunction with a pump to pressurize the unfiltered water that is pumped to the reverse osmosis filtration unit.

A system for reverse osmosis, RO, and for pressure retarded osmosis, PRO, includes: a RO subsystem (10) with a high-pressure RO chamber (11) and a low-pressure RO chamber (12) separated by a RO membrane (13), the high-pressure RO chamber (11) having a RO feed inlet (14) and a brine outlet (15) and the low-pressure RO chamber (12) having a permeate outlet (16); a PRO subsystem (20) with a high-pressure PRO chamber (21) and a low-pressure PRO chamber (22) separated by a PRO membrane (23), the high-pressure PRO chamber (21) having a draw inlet (24) and a draw outlet (25) and the low-pressure PRO chamber (22) having PRO feed inlet (26) and a PRO feed outlet (27); an induction motor (30) having a stator and a rotor, wherein the rotor is mechanically connected to an input shaft of a hydraulic pump (31) configured for providing a feed solution to the RO feed inlet (14) and to an output shaft of a hydraulic motor (32) configured for receiving a draw solution from the draw outlet (25). The invention further discloses a method for operating such system for RO/PRO and to the use of such system.

A reverse osmosis system includes a membrane unit, an energy recovery device, high and low pressure inlet lines, and a concentrate line. The membrane unit has a membrane, an inlet for receiving a feed fluid, a permeate outlet for discharging a permeate fluid and a concentrate outlet for discharging a concentrate fluid. The energy recovering device has a turbine portion, a turbine inlet and a turbine outlet, a pump portion, a pump inlet and a pump outlet, a motor, and a motor control unit for controlling the motor. The low pressure inlet line is connected to the pump inlet for supplying the feed fluid at a low pressure. The high pressure inlet line connects the pump outlet with the inlet for supplying the feed fluid at a high pressure. The concentrate line connects the concentrate outlet with the turbine inlet for supplying the concentrate fluid to the turbine portion.

Method and apparatus for batch and semi-batch operation of membrane system using a sweep stream with essentially repeating process flows is disclosed. The method and apparatus are used for separating a source liquid into its constituent solvents and solutes. The method includes circulating a feed stream and sweep stream in a feed side circulation loop and a sweep side circulation loop, respectively, in a counter-current, or co-current or cross-flow configuration. The pressure in the feed loop is gradually increased to initiate flow of solvent from the feed loop to the sweep loop. The concentrate and diluate streams obtained may be continuously removed. The applied feed loop pressure is continually increased until maximum desired operating pressure is reached or maximum concentration of a solute is reached in the feed solution. The method extends the maximum achievable salt concentration of RO process to at least about 300 g/L NaCl.

A reverse osmosis system includes a first pretreatment system and a fluid source located below a reservoir. A first membrane housing has a reverse osmosis membrane therein. A first turbocharger includes a first pump portion and a first turbine portion. The first pump portion receives feed fluid from the first pretreatment system, pressurizing the feed fluid and communicates the feed fluid to the feed fluid inlet. The first turbine portion receives brine fluid from the brine outlet. The system further includes a second and third turbocharger. A second turbine portion and the third turbine portion receive brine fluid from the first turbine portion. Second feed fluid is communicated through a booster pump, a second pretreatment system, and second pump portion to increase a pressure of the second feed fluid. The second feed fluid is communicated to the third pump portion which communicates the pressurized second feed fluid to the first pump portion.

The present invention discloses an SWRO and MCDI coupled seawater desalination device system with energy recovery, including a pre-filtering unit, an SWRO treatment unit, an MCDI treatment unit, and a post-filtering unit. The SWRO treatment unit is coupled with the MCDI treatment unit. Seawater desalination is performed through a coupling complementary water passage and circuit design, while water quality is improved, and the continuity of water output from a water passage of the device is kept. By recovering the pressure potential energy of high-pressure brine in the SWRO treatment unit and electric energy released by desorption in the MCDI treatment unit, energy consumption is reduced.

A reverse osmosis system includes a membrane unit, an energy recovery device, high and low pressure inlet lines, and a concentrate line. The membrane unit has a membrane, an inlet for receiving a feed fluid, a permeate outlet for discharging a permeate fluid and a concentrate outlet for discharging a concentrate fluid. The energy recovering device has a turbine portion, a turbine inlet and a turbine outlet, a pump portion, a pump inlet and a pump outlet, a motor, and a motor control unit for controlling the motor. The low pressure inlet line is connected to the pump inlet for supplying the feed fluid at a low pressure. The high pressure inlet line connects the pump outlet with the inlet for supplying the feed fluid at a high pressure. The concentrate line connects the concentrate outlet with the turbine inlet for supplying the concentrate fluid to the turbine portion.

A system and method of operating the same includes a membrane chamber comprising a membrane, an inlet, a concentrate outlet and a permeate outlet. The membrane chamber is located in a body of water at a predetermined depth. A turbocharger is disposed at about the predetermined depth and includes a pump portion coupled to the inlet of the membrane chamber and a turbine portion coupled to the concentrate outlet. A pump communicates pressurizing feed fluid and communicates the feed fluid to the turbine portion of the turbocharger though a feed pipe. A permeate pipe extends from the permeate outlet to about the surface of at the body of water.

The present application includes a symbiotic reverse osmosis train system for maximizing desalinated water recovery, meanwhile yielding high salinity brine suitable for osmotic power generation or commercial salt production. The trains comprise a series of cells operating in an interrelated sequential pattern within a salinity field. Each cell forms a closed hydraulic brine loop having pumping means, power recovery means and shared semipermeable membranes between adjacent cells. Used are a semipermeable Flat Sheet or Hollow Fiber Membrane in desalination and osmotic power generation of brackish, seawater and brines of 15% salinity or more. Charging each cell in the train of cells with a formulated brine having a specified ionizable inorganic salt concentration and type, without permitting mixing of the given brines among adjacent cells. Allowing the train to achieve water recovery exceeding 85% with concentrated rejected brine of 28-30% salt content.

A process for treating waste water, including the steps of extracting by forward osmosis treated water from a wastewater feed stream and transferring it to a saline draw stream, and extracting from the saline draw stream treated water by a reverse osmosis process.