Later on, devices were created which disposed of waste and urine, and I believe it is on the International Space Station where urine is now recycled rather than disposed of.
Lol - I think urine is recycled into water, perhaps for cooling systems or something, and waste might be used for fertilizer if they're growing their own food. Just a guess.
An interesting source from the 14th century about : “Alice Wade, who lived in 14th Century London, could not countenance the smell of her own poo“http://www.bbc.co.uk/news/magazine-12847529