Treatments for kidney failure: Dialysis machines filter blood. Dialysis has to be carried out regularly to keep the concentration of dissolved substances in the blood at normal levels, and to remove waste substances. The dialysis machine filters flood between partially permeable membranes, surrounded by dialysis fluids. The membranes are small enough to filter ions and waste substances, but not large enough to filter large molecules such as proteins. Only waste substances can be filtered out due to the dialysis fluid having the same concentration as blood. Kidney transplant - A cure but can be rejected by the receiver's body. Doors donate 1 of their kidneys for people who require them, this increases the life expectancy of that person, however, the donor can be rejected by the body after the operation.