A novel reactor configuration in which blocks of monoliths are arranged in a stirrer-like configuration was studied. A substantial liquid flow rate can be realized through the monolith blades at relatively low power input, owing to the high permeability of the monolithic structure. The inside of the monolithic channels can be coated with a thin layer of either a conventional catalyst or a biocatalyst, thereby eliminating many of the problems associated with using a suspended catalyst. The basic relationship among stirrer speed, geometry, liquid viscosity, and the resulting torque and flow through the blades were studied. Furthermore, the fast decomposition of a dilute, aqueous hydrogen peroxide solution was used to characterize the rate of external mass transfer.