It took/is taking a long while to develop self-driving cars, despite the money and big players chasing it. How long will a fat-berg shark take-a-to-make-a?
Also, think of the people who might help you with this - sewer-diving experts! You are essentially collaborating with them to displace their own roles.
I used to work in retail stocking shelves. 1000% I would have happily collaborated on developing a shelf-stocking robot... if I got paid something for it.