If you are out on the hill for a long day or overnight then at some point the call of nature must be answered. As the level of usage of our mountain environment increases and once quiet spots become busier it seems more and more irresponsible to be using the mountains as one big toilet. So unpleasant as it may seem you have to carry it out with you. In 1997 Cairngorm National Park started the Poo Project to reduce the amount of waste that is revealed by the melting snowpack. They provide bags and containers to use for free and a disposal service.
It’s actually pretty easy to do this at any time of year. You need some compostable nappy bags from the local chemist. These are made from corn starch, so even better than bio degradable, although human waste should not go in your compost bin.
Next get yourself some pooh powder. Pooh powder is like the inside of a nappy, it turns liquid waste into a gel and blocks odours. The waste is than acceptable as landfill in much the same way as a standard nappy. You put a couple of scoops of powder into the nappy bag before you leave home.
Finally get one of these double lock bio waste dry bags from Rab.
If you need to, use the nappy bag with the powder inside. Then use another nappy bag around that and then put the whole lot into a double sealed drybag. Hang it on the outside of your pack or put inside. When you get home, dump the nappy sacks into the bin and wash out the dry bag. A simple system which is pretty cost effective. A tub of the powder isn’t cheap but will last a group of people quite a long time. I have a slightly larger system which we use when wild camping in our van which also works very well.