Haemodialysis: Going Green
This blog is about a hobby-horse of mine: eco-dialysis or, as I call it, "Green dialysis". It is an aspect of dialysis that deeply interests us here in my city of Geelong, Australia.
We began to care about the environmental impact of haemodialysis (HD) when, after establishing the first nocturnal home HD program in Australia in 2000 where >40 home nocturnal HD patients now account for >25% of all our HD, our home patients reported feeling much better, but complained about their high utility costs. As single pass HD is one of the most water and power hungry of all healthcare therapies, and all our home patients use single pass Fresenius HD systems (NxStage has not been a successful system in the Australian context) we decided to develop ways to minimise the water and power costs for our home patients. While our home patients provided the initial impetus for us to assess our utility systems, it soon became clear that water and power savings were as applicable to our facility services as they were to our home patients. We thus decided to address water and power service-wide.
We began by first measuring our water use, water wastage and power consumption. Our local Barwon Health mean mains water use for every 4.5 hour treatment is ~450 litres/treatment with a further 50+ litres used during rinse and idle phases. Thus, more than 500 litres of mains water was being used per treatment. With on-site treatments numbering ~19,000/year, our facility-based water use was ~9.5 million litres/year. At home, where our patients average 7-8 hours of dialysis/treatment and dialyse a mean of 4.5 nights/week, water consumption was ~800 litres/treatment and 200,000 litres/patient/year.
Approximately 2/3rd of the mains water drawn by dialysis water treatment systems is 'rejected' by the membranes of the reverse osmosis (RO) plant when the RO converts drinking water into injectable-grade water for dialysis. In most jurisdictions, regulations and restrictions dictate that water 'rejected' by an RO system as it washes away any remaining salts from the mains water presented to it be directed to the sewer as 'reject water'. This water is, however, quite suitable for human consumption. At worst, is has a slightly higher salt content than mains water —similar to mineral water—but it remains well within World Health Organisation (WHO) limits for drinking water.
It is important to understand that RO reject water is not the same as post dialyser effluent. RO reject water is discarded by the pre-dialysis water filtration process. It has not yet come into contact with the patient or with blood. It is potable water. Yet, by our calculations, we were throwing away ~11 million litres of it each year—and in a region endemically prone to drought.
HD is also power-greedy. Our standard dialysis machine + reverse osmosis system equipment pair use a measured mean of 1.3kWh for every hour of dialysis.
It is sobering to think that if these water and power consumption data were to be applied uniformly to all the ~2.0 million HD patients world-wide, the extrapolated annualized worldwide water use would approximate 33.7 trillion litres and the annual power draw would be ~1.62 trillion kWh.
We have established two parallel environmental programs to address some of these problems.
In 2004-2005, we installed a range of simple, inexpensive tank, store, pump and pipe R/O reject water recycling processes for our hospital in-centre, satellite, and home HD programs. This "grey water," biochemically and biologically within the "potable" water standards of both the WHO and the Environmental Protection Agency (EPA), is now recycled to a range of practical uses including:
- In-center facility: surgical instrument sterilization, janitor services and toilet flushing
- Suburban satellite facilities: off-site school ground, sporting facility, and community garden maintenance
- Home patients: range of garden, domestic laundry and dishwashing, and agricultural options at home.
As the first reported re-use program in the world, our water-recycling projects reclaim and reuse up to 100,000L reject water each week. This has led to a positive community response from our drought-prone region and to major savings in water costs. The return on investment (ROI) for our capital outlay was recovered within 36 months.
In 2010, supported by Fresenius Medical Care (Aust), an 18 solar panel, 23.4 m2 solar array was installed our 4-chair home HD training and support facility. The total equipment and installation cost was A$16,219. This has been the first planned, reported, and operating solar-assisted HD project in the world. The system covers all power drawn by our home training facility and should repay the investment within 8 to 10 years. As current panel life is estimated at 30 years, both free service power and a future income stream should be possible in the 2nd and 3rd decades of operation. We now also offer the installation of a 9 panel array for home patients—an array sufficient to provide all their dialysis-related power needs—the purchase and installation costs being $A3,300.
Far more is both possible and desirable. While on-site autoclave-and-shred systems could reprocess the ~2.5 kg medical plastic waste created by each dialysis into sterile plastic suitable for recycling, our composite 2 million strong world-wide HD unit is currently producing a staggering 780,000 tonnes of plastic waste that enters land-fill or is incinerated. This is at enormous waste disposal and carbon footprint costs to our environment, and is wholly preventable.
Imaginative building design using roof-top spaces for food production—watered by RO reject water—should be standard considerations in new dialysis facility design.
Indeed, we should all be far more critical of the environmental impact(s) of processes like HD. Wiser resource utilization is possible, practical, cost effective and planet-friendly. We commend similar conservation practices to those we have applied here in Geelong to all dialysis services.
Our (rather clunky) but useful website http://www.greendialysis.org describes the simple steps we have taken both at home and in our facilities to 'go green'.
- Agar JWM. Personal Viewpoint: Hemodialysis – water, power and waste disposal. Re-thinking our environmental responsibilities. Hemodialysis International. 16 (1); 6-10. January 2012.
- Agar JWM, Perkins A, Tjipto A. Solar-assisted Hemodialysis. CJASN. 2012: 7 (2); 310-314. February 2012.
- Agar JWM. It is time for Green Dialysis. (Editorial). Hemodialysis International. 17 (4): 474 – 478, October 2013.
- Lim AE, Perkins A, Agar JWM. The Carbon Footprint of an Australian Satellite Haemodialysis Unit. Aust Health Rev. 2013. 37(3): 369-74.