Waste (concentrate) water from the reverse osmosis (RO) unit at the Renal department is now recycled into the main soft water storage break tanks - these are very large tanks and serve our hot water requirements for the main hospital site. The calculated water saving is 3,145 M3/Year or 3,145,000 L/Year - cash saving of £6,300 p.a. - this consumption has been closely monitored since the installation and it can be verified as achieving this reduction on the subsequent water bills.
The installation costs to recycle the RO water (break tank, pumps & pipe-work etc) was in the region of £6k so that the pay back for this scheme was less than 12 months.
Renal Unit, Lister Hospital
Cost savings, reduce water wastage
01/02/2011
completed
£6,000
Infection risk
The water is recovered from the RO water purification system, upstream of the supply to dialysis machines. The system is supplied with mains water (drinking water quality), which it further purifies (softens) to produce ultra-pure water for haemodialysis. Although the waste water is uncontaminated, we considered any possible infection risk from diverting/storing it. We spoke in detail to our legionella water consultants - and we looked at the dilution rates and took a pragmatic view that it was safe to divert the water to the main hot water supply after considering the facts that:
Our mains cold water supplying our site is disinfected using CL02 (carried out by the Trust)
Our soft water is disinfected with CL02 (the Trusts secondary CL02 plant)
The hot water is distributed @ >65 deg C (thermal disinfection)
Robert Jones, Property Services Manager, robert.jones@nhs.net
