macrophages are white blood cells which ingest bacteria. In order to digest the bacteria, which organelle must macrophages have a good supply of?

The organelle needed to digest bacteria would be a
lysosome. Lysosomes are found in most cells, but are particularly plentiful in
macrophages, because these cells engulf and destroy bacteria and other
pathogens.Lysosomes are small membranous sacs of enzymes. There are about forty
different hydrolytic enzymes that have been identified in the lysosomes of
cells.

Once a macrophage engulfs a bacteria by the process
of phagocytosis, the bacteria ends up in a membranous sac called a phagosome. When a
phgosome encounters a lysosome inside the cell, the two membranes fuse. This creates a
phagolysosome, which is where the bacteria get digested.  So in answer to your question,
an active macrophage would probably have an abundance of both lysosomes and
phagolysosomes present.