People who suffer from end stage renal desease frequently undergo dialysis on a fixed schedule. For patients this artificial washing of the blood is a major burden. To remove toxins from the blood, large quantities of dialysis water for clearance are required. Until now there has been no solution so far to recover this dialysate cost-effectively. Therefore a cryo-purification method is being developed by Fraunhofer researchers that clears the water without loosing it. This approach not only reduces costs – it may even pave the way for a wearable artificial kidney by milder long-term dialysis treatment at complete water autonomy.