The series of mono- and bi-metallic catalysts with Pd and/or Cu supported over gamma -Al2O3 was investigated with respect to reduction of nitrate and nitrite ions in water by hydrogen. Pronounced limitations of catalytic performance due to intraporous diffusion of the reactants were observed in the reaction. Catalytic membrane containing the Pd-Cu active component supported over macroporous ceramic membrane-support was prepared, investigated and applied to facilitate the intraporous mass transfer. Forced flow of the reacting solution through the membrane was revealed to increase the effective catalytic activity. The approach explored in this study offers a cost-efficient alternative to the conventional concept of catalytic water denitrification process in a slurry reactor, presuming fixed-bed type operation with macroporous catalytic membranes at high level of catalytic activity.