Brian used to have a friend who worked at a sewage treatment plant years ago. He always tells me the story of when his friend let him take a lorry load of this 'cake' away. He had a landscaping business at the time, mid summer and he was laying new lawns for people.
Anyway, he put this 'cake' under some of these lawns. A couple of weeks later one of the customers called him. It's about that lawn you laid. Brian said well if its gone brown, you haven't watered it like I told you to. Brown? the man said, no, it's the only green lawn in the street, what on earth did you do to it?
So I would say yes, take it. Don't tell the wife if you think she'd object. But I'd have some if I could. Saves it getting wasted.
I mean, what do they do with it?