If I understand correctly, all enemas will be 1 liter of water plus 9 grams of salt.
1. Enema 1 will be immediately expelled and there will be no solution left in rectum/colon.
2. Enema 2 will be held for 30 minutes and then completely expelled before the next one.
3. Same as #2 for the next two enemas.
4. For a total elapsed time of about 2 hours.
5. No enema will be held longer than half an hour
Except for the salt, this should be safe. There is no guarantee an isotonic solution is truly isotonic for any individual, especially when repeatedly introducing the solution. Holding the salt solution will cause the body to actively seek a balance between what’s in the intestines and what is outside them. Basically, a series of saltwater enemas will act as a brine marinade and the recipient could easily experience adverse health reactions.
My advice, if sought, is to maybe use the solution for the first two enemas then use the second two for a thorough clean out to rid the colon of any excess salt. Even after a brine, the meat must be rinsed to get rid of the excess salt.