How an Australian Clinic Conserves Water and Power
By Keith Chartier
Given the seeming abundance of water on Earth, it's hard to comprehend that there is actually a limited supply—only 2.5 percent of all the water on the planet is considered fresh water, the rest is salt water in the oceans and lakes. And as the human population grows, these resources are becoming strained. In fact, an average American family of four can use 400 gallons of water a day, and now 36 states are expected to face water shortage soon, according to a report from the U.S. Government Accountability Office.
Dialysis centers also use an extraordinary amount of water, and much of it sent down the drain as waste. There are ways to combat this trend, namely, through the smarter use of water. It’s possible that by merely saving all of the wastewater every year from the reverse osmosis process in U.S. dialysis clinics, we could supply all of the water needs for a city the size of Salt Lake City. That’s the calculation Australian nephrologist John Agar made after reading a 2008 study showing how reclaimed wastewater in Morocco can be reused for other purposes, such as agriculture.
"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,” said Agar. “This is water pre-dialysis rejected by the reverse osmosis process—not contaminated post-dialysis effluent from the dialysis process."
The research from the July 2008 issue of the American Journal of Kidney Diseases showed 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, according to study author Dr. Faissal Tarrass, of Hassani General Hospital in Nador, Morocco. According to Tarrass, more than 120 liters—nearly 32 gallons— of purified water are required during a typical dialysis session. They estimate that in Morocco alone, facilities use more than 50 million gallons of water each year.
The researchers analyzed the wastewater from a dialysis 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. Also, in their cost analysis, they estimate that recycling dialysis facility wastewater would result in cost savings of 20 percent to 30 percent in comparison to desalination of seawater.
Saving more than 7 billion gallons of water is an enticing prospect, but can it be done? Dr. Agar and his associates at Barwon Health in the southern Australian coastal city of Geelong may have figured out a way to do this.
Practical Water Savings
Australia has a sizable home hemodialysis population whose dialysis is completely paid for by the state. There is also a sizable incentive for home dialysis. In the state of Victoria, for each patient that goes home, the dialysis unit gets $10,000 each year per patient in additional funding. Peritoneal dialysis gets $2,500 (Right now, the Australian and U.S. dollars are worth just about this same). This has led to approximately 12 percent of Australian dialysis patients to go home. In Agar's unit, 31 percent of the patients are home dialysis patients.
"The government recognized that home hemodialysis is not only outcome rich, but it’s also funding rich as well in terms of a lesser cost to government to maintain patients in the home than it is to maintain patients in the centers," Agar said. "They have incentivized the home programs such that it is to the benefit of the service to send patients home and not keep them in the centers. They also listened to us on the water."
Australia is a drought-prone nation, and this makes water expensive. They do not use NxStage in Australia, but rather larger dialysis machine in the homes. Therefore, home patients use large amounts of water at their homes, and that was an extra cost that was not covered by the government. To help these patients, Agar and his team started looking at their water consumption and waste, especially from the reverse osmosis machines in the clinics. "We found that we were throwing away reject water anywhere up to 60 to 70 percent of the presented main water to the RO." Agar said. "That amount was being rejected to allow the rest through to the [dialysis] machine."
Based on their dialysis flow rates, Agar and his team began to measure what was being rejected by the RO and found that they had 1,100 mL going down the drain. "We thought, 'Hmm, that’s a bit of a pity, the RO water was better than drinking water, except it has a slightly higher salt content,'" Agar said. "We asked 'how does that salt content, that conductivity of the RO reject water match potable water standard by AAMI, EPA, WHO.' We found that the reject water that we were throwing away, the 1,100 mL/min per machine, fell within all national and international requirements for drinking water, including conductivity. So I potted a couple of liters of that and went down to the local supermarket and got some mineral water off the shelf and I potted that in another jug and took it along to a Barwon Health board meeting. I said, 'here I have a glass of A and a glass of B and tell me which one is the reject water and which is the mineral water.' Fifty percent got it right, and 50 percent got it wrong."
That led Barwon Health to realize that it was throwing away a lot of water. They then did the calculation of how many dialysis machines they had and were able to measure the total facility and home reject water losses, and it came to around 100,000 liters a week.
"Why would you throw it away?" Agar asked. "This is not post-patient water. This is before the water ever gets to the patient. This is not used dialysate."
