Reuse of Reject Water from Reverse Osmosis for Steam Production

Key learning point

By redirecting clean reject water to the boiler house for steam production, the hospital achieves significant water savings, reduced sewerage costs, and greenhouse gas savings.

Setting/Patient Group: Dialysis Unit

Issue to be addressed:

Reverse osmosis water purification for dialysis results in large quantities of water being rejected. The rejected water is currently sent to the drains, despite being perfectly clean with a slightly raised mineral content

Intervention:

• The project captures reject water in the dialysis unit and directs it to a sump pump.
• The water is taken for use in the boiler house and processed into steam

Outcome:

Social   

• Minimising water wastage for wider community

Environmental

• 13.4 million litres of water saved annually.
• Estimated 13,836 kg of CO2 saved annually.

Economic

• > £15,000 saved per year on mains water and sewerage
• Anticipated return on investment within 5 years: 67%

From an implementation perspective, staff nurse Dan Speakman has lobbied the capture of waste water for some time and the intial project idea was raised two years previously. His persistance in keeping the idea alive has paid off as water saving has more recently been recognised as an opportunity to make a saving.