Processes for Filtering Liquids Using Single Pass Tangential Flow Filtration Systems And Tangential Flow Filtration Systems With Recirculation of Retentate

A method of filtering a liquid feed, comprising:

• i) passing a liquid feed through a tangential flow filtration (TFF) system that comprises:
• a plurality of stacked filtration modules that are fluidly connected, each filtration module comprising:
• a single manifold segment comprising a first manifold for receiving and carrying the feed into the filtration module, a second manifold for receiving and carrying retentate out of the filtration module, and a third manifold for receiving and carrying permeate through the filtration module;
• and
• one or more TFF capsules that are positioned on one or both faces of, and are fluidly connected to, the manifold segment,
• wherein the manifold segments are stacked and the manifolds in the manifold segments are coupled to create a centralized serial flow path through the system for feed and retentate and wherein each subsequent filtration module has a total filtration area equal to or less than the previous filtration module;
• a feed inlet on the first filtration module in the system;
• a retentate outlet on the last filtration module in the system;
• a recirculation loop for recirculating retentate through all or part of the system;
• and
• at least one conduit for recirculating retentate;
• the TFF system having a liquid flow path that is parallel into the capsules in each filtration module and serial through the manifold segments in adjacent filtration modules by coupling the first manifold in each manifold segment to the second manifold of an adjacent manifold segment, such that the retentate of one module serves as the feed for the manifold segment of the next filtration module, except that the first manifold in the manifold segment of the first filtration module in the system is connected to the feed inlet and the second manifold in the manifold segment of the last filtration module in the system is connected to the retentate outlet;
• and
• b) recovering permeate in a permeate container and a portion of the retentate from the system in a retentate container without recirculation through the TFF system;
• and
• c) recirculating the remainder of the retentate through all or part of the TFF system at least once, thereby filtering the liquid feed.