Does the World Bank impose interest on the loans it provides?

As Jawwad Farid pointed out, they do. Typically, World Bank (and IMF), charge 0.5% on top of their cost of borrowing (at a very minimum).

If you're familiar with Brenton Woods Project, they have a very apt answer to this very specific question: How does the World Bank operate?

Interest rates on World Bank loans are revised every six months and typically, the Bank charges borrowers a rate of interest 0.5 per cent above its own cost of borrowing on the international market, the proceeds going towards paying the Bank's operating costs and to add to reserves.