I don't why people give you low score. It is good shot of a person do hard work for a living!
But watch out for the Garbage Collector on Cape Cod if you are famous.
I like your idea for the challenge. This is one job I personally would not want to do. For me, had the background been blurred out some it would have been better. That and not cutting off the top of his head.
I understand by your title that this must be the garbage collector - but I still do not feel it meets the challenge, this could be a snapshot of any guy off the street and how would any of us know differently? Perhaps if he was shown with the garbage or in any kind of action with the garbage so that we could verify for ourselves that he is in fact "The Garbage Collector" - nice snapshot though :)
At first glance, I thought maybe this was entered in the wrong challenge until I read the title. I think your photo would score higher if you were to capture the subject "in action" :)