Disposing of an ostomy pouch is easy, when you’re changing your pouch you take it off and put it in a zip lock or other plastic pouch, then zip to lock it or tie a knot and put it in the trash. Using a dark bag is a more discreet way to dispose of your ostomy pouch, especially handy when you’re a friend’s house. Some people carry dog poop bags with them to use, and some of the manufacturers include plastic disposal bags when you order your ostomy pouches.
If you wear a two-piece, the disposal bags are usually packaged with the ostomy pouches. Just pull everything off, throw it in the bag, tie a knot, and put it in the trash. If you’re worried about it smelling up the room you can take it straight to your outdoor trashcan, though most of the disposable bags are actually pretty odor resistant. If you are still concerned about the smell, or have to hold on to the old ostomy pouch for a while before you get to a trashcan, there are attachments you can purchase that clip on to the back of a 2-piece system pouch, keeping all of the effluent and odor in the used ostomy pouch.
Many people with colostomies use closed-end pouches and change them as needed, putting the used one in a disposable bag and tossing it in the trash. You could easily use a ziplock bag to get rid of soiled ostomy pouches. Going through a lot of closed-end pouches means a lot in a landfill, but there are some cool flushable products out there that you can use too.