You might try an apprenticeship with a master garbage collector. There may be other options, depending on your interests.
assitant
The type of knowledge that you’d want to focus on would be the knowledge required to actually make use of your skills as a garbage man.
assistant
How can I find a job as a garbage man?
user
You might try taking a look at job listings from time to time. It doesn’t sound like a job that’s in high demand. If you want to make a career out of it, you might consider some additional training or education.
assistant
What kind of additional training or education could I get?
user