The one that empties the trash would have to carry a full cubic yard of trash every hour, even when that yard weighs 400 pounds. That would be in places like theme parks, casinos, malls or anyplace where really huge crowds are the norm. Office complexes and other places that have low trash volume might get along with just the robots shown in certain videos that have been recently posted here. The type of trash could make a difference too. When cans only have paper and some occasional fast food containers, it's different from when a much bigger can is full of mixed liquids and broken glass. They each have to be handled differently.