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.

A method of desalinating water, including the steps of when electricity costs between a first predetermined price and a second predetermined price, fill water is pumped into a reverse osmosis desalination unit to yield desalinated permeate and saltwater having a first salinity, when electricity costs less than the first predetermined price, fill water is pumped into a reverse osmosis desalination unit to yield desalinated permeate and saltwater having a second salinity, and when electricity costs greater than the second predetermined price, pure water is flowed into a reverse osmosis unit to yield pressurized saltwater which is run through a turbine to generate electricity. The first salinity is lower than the second salinity.

This specification describes membrane based filtration and softening systems and methods. A system has a microfiltration or ultrafiltration (MF/UF) membrane unit upstream of a nanofiltration or reverse osmosis (NF/RO) membrane unit, optionally with no intermediate tank. In some cases, the system and method may be used with feed water provided at municipal line pressure to the membranes. NF/RO permeate is collected in a tank and then pumped to a header. Treated water may be drawn from the header for use or recycled to the system, for example to backwash or flush one or both of the membrane units. In a combined process, NF/RO permeate flushes the feed side of the NF/RO unit and then backwashes the MF/UF unit. In another process, the MF/UF unit and NF/RO unit are filled with NF/RO permeate before being placed in a standby mode.

A single-use device for filtration of a large volume of medium including a plurality of single-use filter units, at least some of which, preferably all of which, are connected to each other by rigid pipes. The filter units include at least one prefilter and at least one main filter for virus filtration which is configured as a hollow fiber capsule.

A method for fractionating a sulfuric acid process stream having at least 1 wt % sulfuric acid, using a treatment system comprising three filtration assemblies each having membranes that are suitable to pass less than 10% salt in a standard test such that average passage of sulfuric acid from the first and third filtration assemblies is less than 30% and average passage of sulfuric acid from second filtration assembly is more than 70%. The system produces a fraction of the stream with a pH between 4 and 10, and a second fraction that contains at least 20 weight percent of sulfuric acid.

The present invention provides a novel floating and renewable energy-powered desalination vessel, which also functions as a wind turbine generator and wave energy generator platform. With energy derived from the wind and waves, the vessel performs reverse osmosis within a vertically positioned cylindrical section extending below a buoyancy chamber. The cylindrical section contains reverse osmosis membranes located above a seawater screening and filtration system, which serve as ballast. The entire vessel and power systems are configured to have the center of mass below the center of buoyancy, forming a vertically stable floating structure with minimum pitch, roll, and wave heave in high sea states. The electric power generated is utilized internally to produce desalinated water or hydrogen from the desalinated water's electrolysis, power an onboard data center, or power delivery to a shoreside power grid. In addition to a wind turbine generator and a wave energy generator, a photovoltaic array or a marine current generator may be utilized to power these applications. Alternatively, the desalination vessel operates with the assistance of shore-based power provided by cable.

A biogas upgrading system can include a multiple stage membrane system that is configured to remove oxygen so that the biogas is upgraded to have a higher concentration of methane, a pre-selected oxygen (O.sub.2) concentration (e.g. less than or equal to 0.2 mol %, etc.), and a pre-selected carbon dioxide (CO.sub.2) concentration (e.g. less than or equal to 5 mol %, etc.). The membrane system can be configured to reject O.sub.2 by utilizing a low CO.sub.2/O.sub.2 selectivity that is within a pre-determined range (e.g. less than 5 or less than 4.5). In some embodiments, the upgraded biogas that is output from the system can be entirely made up of methane, carbon dioxide, and oxygen. In other embodiments, the biogas can be almost entirely composed of these components along with a small amount of nitrogen and a trace amount (e.g. less than or equal to 0.2%-0.1%, etc.) of other components.

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 method exosome purification and characterization is contemplated, comprising the steps of secondary two-stage tangential ultrafiltration to produce an extracted solution, pretreatment of the extracted solution for characterization, characterization of the extracted solution to detect particle size and concentration, and freeze-drying of the extracted solution. An exosome purification integrated device is also contemplated. Through the disclosed methods and devices, exosomes may be better purified and characterized in a manner that results in high practical value to overcome the problems associated with conventional exosome purification processes on the market today, including tedious purification processes, long durations, and high costs.

This specification describes membrane based filtration and softening systems and methods. A system has a microfiltration or ultrafiltration (MF/UF) membrane unit upstream of a nanofiltration or reverse osmosis (NF/RO) membrane unit, optionally with no intermediate tank. In some cases, the system and method may be used with feed water provided at municipal line pressure to the membranes. NF/RO permeate is collected in a tank and then pumped to a header. Treated water may be drawn from the header for use or recycled to the system, for example to backwash or flush one or both of the membrane units. In a combined process, NF/RO permeate flushes the feed side of the NF/RO unit and then backwashes the MF/UF unit. In another process, the MF/UF unit and NF/RO unit are filled with NF/RO permeate before being placed in a standby mode.