Recycled Hemodialysis Water a Boon to Drought-Stricken Areas

August 12, 2014, 10:06am EDT

Hemodialysis centers use a huge amount of water, but now, research shows that this water can safely be recycled for agricultural purposes, saving money for the dialysis center at the same time.

The process of recycling water from dialysis facilities is feasible and cost-effective, Dr. Faissal Tarrass and colleagues, of Hassani General Hospital in Nador, Morocco, report in the July issue of the American Journal of Kidney Diseases, the official journal of the National Kidney Foundation

In parts of the U.S., as elsewhere in the world, water is becoming a dwindling natural resource due to global warming, climate change and recurring droughts. Alternatives are needed to the current practice of simply discarding all the water used for hemodialysis into municipal sewers.

"Hemodialysis is required by patients with chronic kidney failure, when the kidneys can no longer remove enough wastes and fluid from the blood," Joseph Vassalotti, MD, Chief Medical Officer of the National Kidney Foundation said.

In hemodialysis, Dr. Vassalotti explained, a dialysis machine and a special filter called an artificial kidney (dialyzer) is used to remove wastes and fluid from the blood. In general, the dialyzer has two entry ports, one for the blood and one for a washing fluid called dialysate, separated by a thin membrane. Excess water and small waste products pass from the blood through the membrane and are washed away through an exit port.

However, large amounts of water are used to prepare the dialysate and to rinse and reprocess the dialysis membranes and machines.

According to lead author Dr. Tarrass, more than 120 liters of purified water are required during a typical dialysis session. They estimate that in Morocco alone, water hemodialysis facilities use more than 50 million gallons each year

Dr. Tarrass and associates analyzed the wastewater from a hemodialysis facility and found that the only problem in reusing hemodialysis wastewater is its high salt content. Otherwise, their measurements showed that the water discharged from the facility met standards set by the World Health Organization and the United Nations Food and Agriculture Organization for use in irrigation and landscape use after desalination.

In their cost analysis, they estimate that recycling dialysis facility wastewater would result in cost savings of 20% to 30% in comparison to desalination of seawater.

According to Dr. John W. M. Agar from Barwon Health in Geelong, Australia, "There is a clear challenge to rethink our dialysis wastewater policies, and we must rapidly explore the potential for innovative wastewater reuse."

In an editorial published with the report, Dr. Agar points out that much of the water used to prepare the dialyzer membranes would not even require desalination, and writes that "facility-based reject water has provided water for sterilizer steam generation, janitor stations, maintenance and landscape care." It can also be used to supply toilets and laundries.

"I estimate that the U.S. is likely to be discarding around 7.13 billion gallons of grade ‘A’ potable water from their dialysis processes per year," says Dr. Agar. "This is water PRE-dialysis rejected by the reverse osmosis process -- not contaminated POST dialysis effluent from the dialysis process. That's about the annual water use for a U.S. city the size of Salt Lake City!"

"The Tarrass report in this edition of American Journal of Kidney Diseases provides our wake-up call," Dr. Agar concludes. "Let us hope it leads to further innovative reuse ideas for one of nature’s most precious resources – water."

For the actual study visit American Journal of Kidney Diseases here.