The problem with digging a hole on very busy routes like the
Camino Frances is that there are so many people who will have already 'been' there before you. And you are never far from 'civilisation' - houses, fields where people work etc.
Generally it is advised that burying the actual waste (in more remote parts of the world) might be ok if it is VERY deep, and well away from water courses, but that paper, tampons and such like should never be buried because animals, birds etc dig them out and then they blow around. Very nasty.
I think that the best solution is to keep plastic bags in your pockets and use them for all solid waste, paper etc, tie it up and carry it with you until you come to a rubbish bin. Like people here in the UK do for their dogs.
Ideally one should try to 'go' in a toilet in a bar or in the albergue but sometimes the urge comes in most inconvenient places!!
This forum has even had discussions about women and pee-ing! The various suggestions (in order to NOT leave paper around) were (as I recall)
1. as above, use a bag
2. wear a panty liner which will catch the drips or
3. keep a hanky in your pocket to use and rinse it out each night
best wishes
B