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 new and innovative power and treated water co-generation system is provided that includes a modified Kalina cycle and a forward osmosis (FO) membrane. The Kalina cycle of the provided system is used for power production, whereas the system's FO process is used for water production. The provided system modifies a typical Kalina cycle to include a more efficient and relatively low-temperature heat source, while still utilizing the same working fluid, which is ammonia-water. The draw solution for the provided system's FO process is also ammonia-water, which is known and efficient for desalination and wastewater treatment. In some aspects, the working fluid of the system may be a specific ammonia-water composition including between 30-95% ammonia. The presently disclosed system combines the Kalina process and the FO process into an improved and innovative heat integration system to minimize energy requirements and enable operation at both small and large scales.

A device for exchange of water molecule and temperature between two fluids. The device comprises thin molecular sieve membrane sheets that allow water molecules to permeate through while blocking cross-over of the exchanging fluids. The device provides two sets of flow channels having a hydraulic diameter ranged from 0.5 to 2.0 mm for respective process and sweep fluid flows. The two sets of the channels are separated by a membrane sheet having a thickness less than 200 μm. The thin molecule sieve membrane may be prepared by forming an ultra-thin zeolite membrane layer on a porous metal-based support sheet which provides very high water permeance so that the exchange can be conducted in a compact membrane module at high throughput. The device can be used to remove water from a process stream of higher water content by use of a sweep fluid of lower water content or higher water affinity. For example, the device can be used to condition outdoor fresh air close to the temperature and humidity of indoor air by conducting humidity and heat exchange between the fresh air flow drawn from outdoors and waste air discharged indoors.

A water desalination system includes a first set of ultrafiltration membranes, a second set of ultrafiltration membranes, a first backwashing system configured to treat at least one of the first set of ultrafiltration membranes or the second set of ultrafiltration membranes with brine generated by a reverse osmosis process, and a second backwashing system configured to treat at least one of the first set of ultrafiltration membranes or the second set of ultrafiltration membranes with one or more chemicals and reverse osmosis permeate water.

A method of operating a dual reverse osmosis/pressure retarded osmosis plant, including when electricity costs less than a first predetermined price, moderate salinity water is pumped into the first portion of a pressure vessel having first and second portions separated by a water permeable/salt impermeable osmotic membrane to yield desalinated permeate in the second portion and brine in the first portion. Further, when electricity costs greater than the first predetermined price, low salinity water is pumped into the second portion and brine is pumped into the first portion to yield pressurized moderate salinity water in the second portion which is run through an energy recovery device to generate electricity. The salinity of the low salinity water is lower than the salinity of the moderate salinity water, and the salinity of the moderate salinity water is lower than the salinity of the brine.

A reverse osmosis arrangement is described, the first chamber (5) having a first port (7) and a second port (8) and the second chamber (6) being connected to a permeate outlet (9), wherein the first port (7) is connected to a first pump (13). Such a reverse osmosis arrangement should be operated with high efficiency. To this end the second port (8) is connected to a second pump (14).

A system and process for concentrating a lithium stream is disclosed. The lithium stream is directed to a reverse osmosis unit which produces a concentrate containing lithium compounds. The RO concentrate is directed through two pressure retarded osmosis (PRO) modules connected in series. The two PRO modules further concentrate the RO concentrate and at the same time yield a diluted brine that is effective to drive an energy recovery device. The RO concentrate leaving the PRO modules is directed to an osmotically assisted reverse osmosis (OARO) module which also further concentrates the RO concentrate.

A heat power management system is disclosed for an alternating current (AC) power controller for use with portable reverse osmosis water purification systems requiring precise control of a heating action for an internal water heater coupled with energy savings and the reduction of AC line disturbances. The heat power management system is designed to operate with various international electrical systems while protecting such system from excessive current draws.

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 desalination system has a combined displacement pump and displacement pressure recovery motor that propagate feed water with a structurally fixed recovery rate and structurally stabilized volume flow through continuously alternating discharging and recirculation intervals. Thereby enabled is an instantaneous discharge of the entire feed water concentrate and unmixed replacement with low salinity source water that intermittingly and effectively flushes the reverse osmosis membranes. This in turn provides for high recirculation peak salinity and recovery rate that are simple and reliably controlled without impairing membrane longevity.