mucus discharge in bum

Do you have a loop ileo? The mucous is naturally produced by the intestine. The green will be bile filtering down from your stomach. You will be losing lots of fluid with a loop ileo, so you need to drink lots. Try electrolyte replacement drinks like Gatorade, Lucozade, Powerade. Also using sachets mixed with water, like Dioralyte (sp?) will help.
Don't worry about the anal discharge, doesn't sound abnormal to me. I have an end ileo, but still purge mucous from my remaining rectum several times a day.

I am 9 months post op with a temporary loop ileo and I have mucus discharge, sometimes off-white, sometimes greenish-brown. Might have it steady for a week and the not at all for a while. Of course, my j pouch is currently hooked up to my rectum, so my surgeon told me it was the lining of my j pouch that was replacing itself. Also, I was told I would always have to drink lots...and lots...and lots. I also increased salt intake. Not sure what your surgeon recommended, but I was told to drink 3 liters a day, so I had to actually schedule my fluid intake in the beginning, because it was so much more than what I was used to. Now, my body gets thirsty a lot faster and it "reminds" me more. But I also go everywhere with a Gatorade or water. Hang in there.