Participants underwent 24 hours in-hospital treatment with the Wearable Artificial Kidney (WAK). Up to 10 subjects with ESRD will complete the protocol in its entirety. The objective of this protocol is to provide additional preliminary data supporting the hypothesis that the WAK safely and effectively delivers dialysis therapy that is at least equal to the current standard of care for treatment of ESRD using conventional machines for thrice weekly hemodialysis treatments. These objectives would be accomplished by absence of adverse events during treatment with the WAK, along with effective removal of fluid and solutes at least equal to those delivered with conventional currently used dialysis machines. The WAK will be the only investigational device used in this study. The reason for this trial is to advance the eventual approval of this device to be legally commercialized as it potentially may respond to the unmet public health needs to improve outcomes and reduce costs in the treatment of ESRD patients.