Urgent need to reduce power and water waste in dialysis units: Australian study


By Mardi Chapman

25 Mar 2024

Power and water usage in haemodialysis facilities remains high, prompting a call for efficiency to be considered during procurement and in the operation of different systems .

As well, regular audits of resource usage in dialysis facilities should be conducted in order to encourage future improvements, the authors of a Victorian study say.

The study, published in Kidney International Reports [link here], reviewed power and water usage over two sequential two-week periods at the 15-chair Essendon Fields (EF) haemodialysis facility and the 12-chair Barwon Health North (BHN) facility.

The study, led by Dr Katherine Barraclough from the Royal Melbourne Hospital, found the average total power consumption at EF was 5.3 kWh per treatment comprising 3.1 kWh for the reverse osmosis (RO) plant and 2.2 kWh for the dialysis machines.

The estimated water consumption at the facility was 357 l per treatment. Of the 7.1 m3 of mains water coming into the RO plant per day, about 54% was discarded.

Meanwhile the BHN facility used about 10-12 kWh power per treatment comprising 7.2 kWh during automatic operation of the RO plant or 8.7 kWh during manual operation of the RO plant plus 3.1 kWh for the dialysis units.

Estimated per-treatment water consumption in manual and automatic modes were 754 l and 548 l, respectively. RO plant water usage was about 11.1 m3 in manual mode and 8.1 m3 in the automatic mode.

The study authors said there were lessons to be learned from the differences between the two facilities.

“We found substantial differences in per-treatment resource consumption between them as follows: average power usage was almost 2-fold higher and average water usage 1.5-fold higher at BHN than at EF, when the BHN RO plant was operating in the efficient automatic mode,” it said.

“When BNH’s RO plant was operating in manual mode, energy and water consumption were even higher.”

The researchers said the differential power usage was largely due to a more efficient RO system at EF.

“However, the BHN hemodialysis machines also used 41% more power compared with the EF machines due to their greater size and functionality,” they said.

“The EF RO system recirculates water sitting in the loop (∼500 l) at RO system start up rather than discarding it, as occurs at BHN. Furthermore, the EF system is set to recirculate 60% of water rejected at the RO membrane compared to 50% at BHN,” they added.

Dr Barraclough and colleagues said the BHN data demonstrates the importance of ensuring the most efficient RO settings were applied.

“In addition, where RO systems are unable to modify the amount of water circulated in response to demand, it is important to ensure the RO system is sized to match the number of hemodialysis chairs, and that the number of treatments provided at any one time is maximised.”

“… if BHN were to have utilised all 12 available chairs each session, water consumption would have fallen from 548 l to 391 l per treatment when the RO was operating in the automatic mode, which is comparable to EF per-treatment consumption.”

In other take-away messages, they suggested:

  • the installation of submetering equipment into new-built dialysis units should be mandatory to facilitate monitoring of resource usage
  • high observed power usage at facilities could be offset by locally generated solar power
  • capturing RO reject water for reuse should be considered
  • standard metrics of efficiency were required to permit comparisons between equipment from different manufacturers.

“In the current era of escalating climate change and resource scarcity, this must be addressed as a matter of urgency,” they concluded.

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