Abstract: A large capacity filter assembly A comprising of a housing B, a filter chamber C, and a horizontal trap chamber D. Water flowing from industrial drain line 10 enters housing B, flows through filter chamber C, ingress horizontal trap chamber D and exits housing B. Horizontal trap chamber D is disposed within housing interior 12 for trapping noxious odors stemming from the drain line and preventing the noxious odors from permeating through housing inlets 16. Horizontal trap chamber D includes horizontal baffle plate 28, first vertical trap channel opening 32, first vertical trap channel 38, first horizontal trap channel 36, second vertical trap channel 44, second horizontal trap channel 42, and airspace 46.