A peritoneal-based (bloodless) artificial kidney processes peritoneal fluid without need for additional fluids (waterless). Fluid is separated into a protein-rich stream and a protein-free stream. The protein-rich stream is regenerated using a sorbent assembly, and its protein composition can be modified by removal of selected protein(s) (dialysate-pheresis). It is then reconstituted with additives and returned into the peritoneal cavity, thereby reducing protein-loss and providing oncotic-pressure for ultrafiltration. The protein-free stream is used to produce free water, and an alkaline or acid fluid for optimization of the composition of the regenerated stream. The unused protein-free stream can be used to reverse flush the separator to maintain its patency and the excess discarded for fluid-balance regulation. Compared to prior art, immobilization of urease allows more protein rich fluid to be regenerated and re-circulated into the peritoneal cavity for toxin removal and allows practicable development of portable and wearable artificial kidneys.
