Peritoneal dialysis is a method of renal function, equivalent to hemodialysis. The treatment lasts 20-30 minutes and is done during the doctors' wishes. (usually every 6 hours when it comes to the manual procedure, ie 4 times a day).
There are 2 types:
1) Manual, every 6 hours, with fluid exchange, called Continuous Ambulatory Peritoneal Dialysis (CAPD)
2) The Automatic which occurs at night as the patient sleeps through a machine and is called Automated Peritoneal Dialysis (APD).
All patients start from the manual and when they are 4-6 weeks then diagnostic tests are done and if everything works according to the data the doctor thinks, then the patient can join the night, something that, as you understand, makes life much easier.