There is a product called Odoban. It comes in a gallon container that you then mix with water. It is amazing. I had moved into in a basaement apartment that had a concrete covered walk to the entrance and someone's cat would pee in the walk way so that it stunk so bad you couldn't breath. I used this product for about a week or so, would soak down the cement and even the walls and ceiling. The smell went away and the cat never came back to pee there.
I also used it on wood paneling and carpeting to get rid of the smell of cigarette smoke when I quit and it was incredible. No one ever knew that I had smoked in that apartment. I copied the link below to the one website I could find.
this is a must for all pet owners!
It is also sold at select Walmart stores, Sam's Club and here is the companies direct website