Water Use and Water Saving Strategies in Dialysis, Room for Improvement?

Dialysis treatment consumes a significant amount of water and energy, which entails an important waste management effort. Those variables play a relevant role on the total cost of a dialysis session. Strict dialysis water and ultrapure dialysis fluids standards were established as a pre-requisite for online convective therapies (e.g., hemodiafiltration), improving biocompatibility of the dialysis system, reducing inflammation profile of the dialysis patients, enhancing the responsiveness to erythropoiesis-stimulating agents and thus having the potential for improved survival. The main purification step of a dialysis water treatment system is the reverse osmosis. Fouling of reverse osmosis membranes remains a major issue and all effort should be made to reduce it, to ensure a constant output. Naturally occurring waterborne filamentous fungi, yeasts, bacteria and fragments may contaminate dialysis water and, consequently, dialysis fluids. To maintain the dialysis water treatment system under proper conditions and fulfilling the dialysis fluids quality standards there is a need of a significant effort, namely in terms of cleaning and disinfection procedures of the reverse osmosis, distribution systems and dialysis machines. Improving the reverse osmosis inlet water quality profile by installing an Ultrafiltration system as a pre-treatment, could have an impact in terms of dialysis water quality outcomes, water and energy consumption, and disinfection frequency. The water treatment system efficiency is strongly influenced by the system design and reverse osmosis setup. System design (i.e., not over dimensioned) with a clear focus on increasing efficiency is mandatory if one wants to decrease the carbon footprint. Dialysis prescription (namely dialysis fluid flow rates) plays an important role in the dialysis fluid consumption and consequently the water consumption. A more environmentally friendly dialysis can be influenced by optimization of the current technology and development of innovative technology, and by the adoption of a conscious and coherent behavior of all persons involved in the daily routine of a dialysis unit.