Multi-cartridge membrane contactors, modules, systems, and related methods

A multi-cartridge membrane contactor that can be used for many purposes, including, but not limited to, being a multi-cartridge degassing module. In accordance with at least particular certain embodiments, the module includes a plurality of hollow-fiber cartridges placed in a radial pattern around a central cartridge within a single larger vessel. For example, there may be two radial sets of cartridges placed in series at each of the radial positions.