The present disclosure relates to a modular fluid modification system having an outer container configured to permit a fluid flow there into at a first location, and to allow the fluid flow to exit the container at a second location spaced apart from the first location. A plurality of fluid contacting elements is housed in the outer container. The fluid contacting elements each form an independent filtering or reactor element. Each fluid contacting element includes a plurality of openings formed in a grid or lattice-like pattern.