I'd just hate to see an honest, law abiding garbage collector lose his job to make room for a convicted felon
Where I live, garbage collection isn't done by government employees but by private contractors. Even were garbage collection remains government work, implementing your idea would probably mean some of the current employees would be displaced by felons. That's hardly fair to the honest workers.
Instead, maybe we should put them to work doing jobs that communities can't afford to fund, such as erosion control in parks and on public lands (that can involve some pretty heavy lifting) and the like.