Running the garbage system is a desk job largely I would expect. It might not be the most stimulating subject matter to you, but I think it's within the realm of possibility that you'd find people who found it an interesting system to manage.

Cleaning the sewers sounds objectionable. I think you shouldn't discount the idea that in a societal structure that's different from ours you'd remove some of the social stigma that comes from such a job. But at the same time, if you observed that very very few people wanted to clean sewers for whatever reason, and there wasn't enough supply to meet demand, then you invest more in technology that reduces the shortfall. As others suggested, automation.