In humans, one role of the kidneys is to remove waste products from the blood. some individuals whose kidneys do not work properly use a medical treatment called dialysis to perform this function. the process of dialysis uses a semi-permeable membrane and dialysis fluid to remove waste products from the blood. a group of students sets up the model to investigate how dialysis works. the fluid in the beaker represents the blood, and the solute molecules represent waste products that accumulate in the blood. the fluid in the bag represents the dialysis fluid, and the membrane of the bag is permeable to the solutes.