Systems and processes for purifying and concentrating a liquid feed stream are disclosed. In the systems, the concentrated liquid output from the high pressure side of a reverse osmosis stage is used as the draw solution in the low pressure side of the reverse osmosis stage in a configuration called osmotically assisted reverse osmosis. This reduces the osmotic pressure differential across the membrane, permitting high solute concentrations to be obtained, hastening the purification of the liquid. Reduced system pressures are also obtained by arranging multiple osmotically assisted reverse osmosis stages in a cross-current arrangement. Overall system energy consumption is reduced compared to conventional thermal processes for high concentration streams.

A high salinity feed water such as seawater is treated to produce a reverse osmosis (RO) concentrate and an RO permeate. Optionally, some or all of the RO concentrate may be filtered to produce a nanofiltration (NF) permeate. Optionally, some feed water can also be filtered to produce NF permeate without first being concentrated by RO treatment. The NF permeate, or a blend of the RO permeate and NF permeate, may be used to produce a product water for injection into an oil-bearing reservoir to enhance oil recovery. Optionally, the product water may have salinity greater than the feedwater, or at least 30 g/L. The product water may have hardness of less than 20 mg/L.

A high salinity feed water such as seawater is treated to produce a reverse osmosis (RO) concentrate and an RO permeate. Optionally, some or all of the RO concentrate may be filtered to produce a nanofiltration (NF) permeate. Optionally, some feed water can also be filtered to produce NF permeate without first being concentrated by RO treatment. The NF permeate, or a blend of the RO permeate and NF permeate, may be used to produce a product water for injection into an oil-bearing reservoir to enhance oil recovery. Optionally, the product water may have salinity greater than the feedwater, or at least 30 g/L. The product water may have hardness of less than 20 mg/L.

A biological treatment apparatus comprising: (a) a vessel; (b) an inlet conduit for providing feed water to an inlet region; (c) an outlet conduit for removal of treated water from an outlet region; (d) an inlet distributor comprising inlet ducts, each in fluid communication with both the inlet region and a porous surface section of the inlet duct wall; (e) an outlet distributor comprising a plurality of outlet ducts, each in fluid communication with both the outlet region and a porous surface section of the outlet duct wall; and (f) a media bed comprising particles in fluid communication with porous surface sections of both the inlet and outlet duct walls; wherein a ratio of the length of an inlet duct to a minimum distance between an inlet duct and an outlet duct is from 15:1 to 2:1.

A system for separating competing anions from per- and polyfluoroalkyl substances (PFAS) in a flow of water contaminated with PFAS and elevated levels of competing anions that includes a separation subsystem which receives the flow of water contaminated with PFAS and elevated levels of competing anions and separates competing anions from the PFAS and concentrates the PFAS to produce a treated flow of water having separated competing anions therein and a flow of water having a majority of PFAS therein. At least one anion exchange vessel having an anion exchange resin therein receives the flow of water having a majority of PFAS therein and removes PFAS from the water to produce a flow of treated water having a majority of the PFAS removed. The separation of competing anions by the separation subsystem increases the treatment capacity of the anion exchange resin to remove PFAS from the contaminated water.

A reverse osmosis filter ram apparatus comprises a base rack having a controllable linear actuator thereon, preferably a hydraulic ram apparatus. The ram apparatus comprises detachable and changeable connection brackets configured to alternately connect to steel reverse osmosis tubes and fiberglass reverse osmosis tubes. The linear actuator comprises a plunger head that is configured to push one or more spools within a reverse osmosis tube for moving tubular reverse osmosis filters therein, either for adding the same from the reverse osmosis tube or removal of the same from the reverse osmosis tube. Systems and methods of using the same are further provided.

A reverse osmosis filter ram apparatus comprises a base rack having a controllable linear actuator thereon, preferably a hydraulic ram apparatus. The ram apparatus comprises detachable and changeable connection brackets configured to alternately connect to steel reverse osmosis tubes and fiberglass reverse osmosis tubes. The linear actuator comprises a plunger head that is configured to push one or more spools within a reverse osmosis tube for moving tubular reverse osmosis filters therein, either for adding the same from the reverse osmosis tube or removal of the same from the reverse osmosis tube. Systems and methods of using the same are further provided.

The present invention relates to shallow water subsea desalination system with a subsea desalination template (20) located on a seabed. A retrievable subsea RO-module (4) is located in a subsea RO-module zone (23) of the subsea desalination template (20) and is connected to a RO-module connection. A seawater booster pump assembly (1) includes a seawater inlet (7) and an outlet in fluid connection with a seawater inlet side of the RO-cartridge assembly. A retrievable subsea booster module (2) includes the seawater booster pump assembly (1). A pressure regulator (11) is in fluid connection with a retentate side of the least one retrievable subsea RO-module (4).

The present invention relates to shallow water subsea desalination system with a subsea desalination template (20) located on a seabed. A retrievable subsea RO-module (4) is located in a subsea RO-module zone (23) of the subsea desalination template (20) and is connected to a RO-module connection. A seawater booster pump assembly (1) includes a seawater inlet (7) and an outlet in fluid connection with a seawater inlet side of the RO-cartridge assembly. A retrievable subsea booster module (2) includes the seawater booster pump assembly (1). A pressure regulator (11) is in fluid connection with a retentate side of the least one retrievable subsea RO-module (4).

A backflow preventer for water filtering equipment, the water filtering equipment has a plurality of filtering units, the filtering units are connected among each other via at a plurality of connectors connected by at least one hose and connected to a water source via the at least one of the connectors, at least one of the connectors has a check valve set, and the check valve set has a check valve and an unidirectional valve. The check valve has an elastic tube with a duckbill valve at one end and is connected to a base at another end, and the base has a socket sleeved onto the elastic tube. The unidirectional valve has a first main portion with a larger diameter and a second main portion with a smaller diameter, the diameter of the second main portion corresponding to an inner diameter of the socket of the check valve.