Filter elements for perfusion systems and methods are provided. A filter element sheet includes a microporous membrane having a mean pore size of at least about 0.65 ?m and a feed spacer comprising woven fibers and having an open area of at least about 35%. The filter element sheet can be arranged within a filter element, for example, in a spiral-wound format or in a cassette format. A perfusion system includes at least one filter element and a pump configured to control flow of a liquid feed through the at least one filter element.

A tunable nanofiber filter device can include a filter housing defining an interior space, the housing having defined therein and inlet and an outlet, each in fluid communication with the interior space, and a plurality of filter laminas disposed within the interior space, each filter lamina including an upper surface, a lower surface, and an aperture defined therethrough. The plurality of filter laminas can be arranged in a stack wherein the opposing surfaces of adjacent filter laminas define a portion of an interlaminar flow space extending between the opposing surfaces. The flow space can be in fluid communication with the apertures of corresponding adjacent filter laminas to form a continuous flow passage extending through the lamina stack from the inlet to the outlet. An array nanofibers can extend into the flow passage from a portion of each filter lamina such that a fluid flowed through the flow passage flows across a portion of said array.

The concentrated and dilute saline water distribution systems of Electro Dialysis Reversal EDR or Capacitive Electro Dialysis Reversal CEDR are modified by feeding and retrieving the saline water to and from multiple spacers in an electrodialysis stack such that (1) the saline water enters and leaves the spacers in the plane of the thin spacers rather than traditionally perpendicular to them and (2) the saline waters are independently fed and retrieved to and from the spacers through long and small cross-sectional area tubes such that the electrical resistance to ion flow is very high relative to the electrical resistance to ion flow through the electrodialysis stack containing the cation and anion exchange membranes and dilute and concentrated saline water spacers. Consequently, little ion flow will occur in the saline water distribution systems and consequently most of the ions flow through the electrodialysis stack of EDR or CEDR providing effective desalination regardless of the salinity levels of the feed waters.

The present invention provides, in various embodiments, hybrid single-pass tangential flow filtration assemblies, disposable single-pass tangential flow filtration assemblies, scalable single-pass tangential flow filtration assemblies and adaptable modular single-pass tangential flow filtration assemblies. In other embodiments, the invention relates to processes for recovering proteins from the surface of a filtration membrane in a single-pass tangential flow filtration assembly and for cleaning a tangential flow filtration assembly. In additional embodiments, the invention provides methods of increasing the processing capacity of a single-pass tangential flow filtration assembly.

A membrane stack comprising the following components: (a) a first ion diluting compartment (D1); (b) a second ion diluting compartment (D2); (c) a first ion concentrating compartment (C1); (d) a second ion concentrating compartment (C2); and (e) a membrane wall (CEM1, mAEM, mCEM, AEM, CEM2) between each compartment and on the outside of the first and last compartment of the stack; wherein: (i) each membrane wall comprises a cation exchange membrane (CEM1, mCEM, CEM2) or an anion exchange membrane (mAEM, AEM) and the order of the cation and anion exchange membranes alternates from each wall to the next; (ii) the membrane walls (mAEM, mCEM) on each side of compartment (a) both have a higher monovalent ion selectivity than the corresponding membrane walls (AEM, CEM2) on each side of compartment (b); and (iii) the stack further comprises a means for communicating fluid between compartments (a) and (b).

Membrane cell stack arrangement comprising a housing, a stack of membranes defining flow compartments and a fluid manifold system, wherein the direction of flow through the flow compartments is different to the direction of flow through entry and exit openings and the width of the entry and exit openings are each larger than 45% of the width of the flow compartment.

A method of filtering a liquid feed is described, comprising passing a liquid feed through a single pass tangential flow filtration (SPTFF) system and recovering the retentate and permeate from the system in separate containers. A method of filtering a liquid feed is also described comprising passing a liquid feed through a tangential flow filtration (TFF) system, recovering permeate and a portion of the retentate from the system in separate containers without recirculation through the TFF system, and recirculating the remainder of the retentate through the TFF system at least once. The methods of the invention can be performed using an SPTFF or a TFF system that comprises manifold segments to serialize the flow path of the feed and retentate without requiring diverter plates.

Fluid treatment assemblies comprising a plurality of adjustable tensioning rod assemblies comprising tensioning rods having a tensioning nut and a locking nut threadably attached to the tensioning rods, and methods of adjusting the tension on the assemblies, are provided.

A process for preparing a membrane stack comprising the steps of: (i) interposing a curable adhesive between alternate anion exchange membranes and cation exchange; and (ii) curing the adhesive; CHARACTERIZED IN THAT said adhesive, when cured, has a Shore A hardness of less than 70 and an elongation at break of at least 50%.

A tunable nanofiber filter device can include a filter housing defining an interior space, the housing having defined therein and inlet and an outlet, each in fluid communication with the interior space, and a plurality of filter laminas disposed within the interior space, each filter lamina including an upper surface, a lower surface, and an aperture defined therethrough. The plurality of filter laminas can be arranged in a stack wherein the opposing surfaces of adjacent filter laminas define a portion of an interlaminar flow space extending between the opposing surfaces. The flow space can be in fluid communication with the apertures of corresponding adjacent filter laminas to form a continuous flow passage extending through the lamina stack from the inlet to the outlet. An array nanofibers can extend into the flow passage from a portion of each filter lamina such that a fluid flowed through the flow passage flows across a portion of said array.