Sure you can use "desecho," but if you want to establish a clearer difference when you have both "waste" and "disposal" in the same sentence, you may use "eliminación" or "destrucción," depending on the process of disposal (e.g., "destrucción" involves incineration or any other destruction process).

These are widely used, and sometimes even preferred, in UN official documents.

Ref. Direct experience with the subject, former UNEP officer and translator.