Poop in outside sink

I am positive it is black water, trust me...the things I have seen cannot be unseen. So I tore apart the sink last evening and it appears that a mouse decided to chew the catch in the sink tail piece to get into the pipe. Then it decided to chew the internals of the waterless drain which cause my issues.

I really like the suggestion to put in a ball valve. That is a great idea. The only issue is that I do not have enough room to have the waterless trap and ball valve installed. It would be one or the other for me.