Kidney dialysis is a life-support treatment that uses a special machine to filter harmful wastes, salt, and excess fluid from your blood. This restores the blood to a normal, healthy balance. Dialysis replaces many of the kidney's important functions. There are different types of kidney dialysis, including: 1  Hemodialysis. 2  Blood is filtered using a dialyzer and dialysis machine. 3  Peritoneal dialysis.