FIG. 1 is a perspective view of a sewage pump embodying the ornamental design of the present invention;

FIG. 2 is front view of the sewage pump;

FIG. 3 is rear view of the sewage pump;

FIG. 4 is side view of the sewage pump;

FIG. 5 is an opposite side view of the sewage pump;

FIG. 6 is a top view of the sewage pump; and,

FIG. 7 is a bottom view of the sewage pump.

The broken line showings of FIGS. 1-7 are for illustrative purposes only and form no part of the claimed design.