A multi-arm spider fitting including a central hub from which such arms radiate. The arms are adapted at their extremities for coupling with filter modules, so that multiple filter modules can be secured to a single spider fitting, with the filter modules being arranged in a compact array to minimize the volumetric and spatial requirements of the filtration system. The multi-module filter assembly may be mounted on a motive cart, to provide for ready transport of the filter assembly between locations in a process plant.