Abstract: Integrated, sequential stages of nanofiltration, forward osmosis, and reverse osmosis and related membranes provide an Integrated Osmosis structure, systems and methods. By optimally placing and using the desired characteristics of each membrane, performance and cost effectiveness not attainable individually is obtained. Integrated Osmosis systems provide high diffusive and osmotic permeability, high rejection, low power consumption, high mass transfer, and favorable Peclet number, by manipulating convection, advection and diffusion, low concentration polarization gradients, low reverse salt flux and effective restoration of performance after cleaning fouled membranes. Benefits include increased permeate recovery and decreased waste concentrate volume from reverse osmosis processes or other elevated osmotic pressure solutions. Integrated Osmosis first employs nanofiltration for selective harvesting of solutes, proffering a reduced osmotic pressure permeate.

Abstract: CO2 absorption and desorption affords differing osmotic pressure metal salt osmolyte draw solutions from a common solution. These draw solutions serve a staged forward osmosis membrane process. First stage draw solution is the lowest osmotic pressure osmolyte. First stage concentrate is fed to the second stage and fresh water is externally extracted from the first stage diluted osmolyte. Concentrated first stage osmolyte returns from fresh water extraction, blends and is heated with solid precipitates of the lower osmotic pressure solute. CO2 desorbs from the lower osmotic pressure osmolyte converting to a higher osmotic pressure osmolyte. The higher osmotic pressure osmolyte serves as second stage draw solution to further dewatering the first stage concentrate. Second stage concentrate conveys to external processing or discharge. CO2 absorption converts the dilute high osmotic pressure osmolyte from the second stage to the lower osmotic pressure osmolyte serving as draw solution in the first stage.

Abstract: A cartridge filter assembly includes a depth filter element and a downstream second filter element. The depth filter element has a mass of melt-blown polymer filaments. The depth filter removes 0.5 to 10 micron sized contaminants at an efficiency of 90% or more. The depth filter preferably comprises multiple zones occupying different depths, with one or more melt-blown polymer filaments traversing two or more of the zones. The second filter element comprises nano-fibers having a diameter of 1 micron or less, and removes a material percentage of contaminants that are less than 1 micron in size, preferably less than 0.5 microns in size. The depth filter element may be in the form of a tube and the second filter element may be in the form of a pleated sheet located inside of the depth filter. The cartridge filter assembly may be used to pre-treat a feed water upstream of an RO membrane. The SDI of the feed water may be reduced to 3 or less or 2 or less.

Abstract: A feed channel spacer for a spiral wound membrane element has inlet and outlet edges that are thinner than the rest of the spacer material. The edges may be made thinner, for example, by passing the edges of a sheet of feed spacer material through a pair of hot rollers or by compressing the edges of the sheet in a heated press. The thinned edges of the feed spacer material are located in the element between glue lines applied to the permeate spacers of the element. The thin edges allow a greater membrane surface area to be provided in a given element diameter. A feed channel spacer may also have an area with obstructions to create micro-mixing effects. These obstructions may be provided on a feed spacer sheet of constant thickness, or one with thin edges.

Abstract: A spiral would membrane element has a feed channel spacer providing a tortuous feed flow path through an open spacer mesh material. The feed flow path may force the feed liquid to flow across substantially all of an adjacent membrane surface. The length of the flow path and average cross-flow velocity are increased relative to a straight flow path. A rise in pressure drop that might otherwise be produced by the increased average cross-flow velocity is reduced by the open spacer mesh. In a system having two or more upstream and downstream spiral wound membrane elements, a downstream element may have a feed channel spacer providing a tortuous flow path while an upstream element has a feed channel spacer providing a less tortuous flow path or a straight flow path.

Abstract: A feed channel spacer for use in a spiral wound membrane element provides a series of generally parallel interior channels. The interior channels extend from an inlet side of the spacer to an outlet side of the spacer, but follow an undulating or zigzagging path. Dean's vortices or other flow patterns that cause mixing reduce concentration polarization. The feed channel spacer is made by pressing a sheet of thermoplastic material in a die.

Abstract: A permeate carrier for a spiral wound membrane element has two or three layers, for example of tricot construction. The two outer, or only, layers resist movement of the membrane sheet into permeate channels in the permeate carrier. The total thickness of the permeate carrier sheet may be similar to the thickness of typical tricot permeate carrier sheets. The permeate carrier sheet may be coated to make its surfaces hydrophilic. The coating may be, for example, a cross-linked polyvinyl alcohol (PVA) or polyvinyl pyrrolidone (PVP). In the spiral wound element, a permeate carrier sheet may be wrapped in one or more layers around a central tube. Channels in the permeate carrier sheet are oriented helically relative to a longitudinal axis of the central tube.