Answer:
The Kidneys are the body's filter as the purify the blood of waste products and certain fluids and salt.
When renal failure occurs, it means that the kidneys will no longer be able to filter the blood like they used to. When this happens one can either get a kidney transplant or they can use a Hemodialysis machine.
This machine filters the blood instead by drawing blood via a needle from the patient and then sending it back in after purifying it in the machine. The machine comes with its own risks however such as blood loss.
It is also recommended that a trained medical professional be the one to operate the machine so as to direct it on what to clean and how long the blood should be cleaned for.
There are indeed potable hemodialysis machines that can be used at home but it is recommended that one do it at a medical center because it would be best to have a trained professional on hand if there are issues such as blood loss, loss of consciousness or an inaccurately set time limit.