The climate crisis is quickly becoming an issue for healthcare services and it’s one that the NHS will soon have to cope with while simultaneously reducing its own carbon footprint.
Since becoming the first national health service to commit to reaching net zero, the NHS has made significant progress in reducing its footprint, which represents 4% of the UK’s overall carbon emissions.
It’s vital that water safety groups have an active role in efforts to decarbonise, particularly given that 80% of the organisation’s carbon emissions come from heating and hot water.
Clearly, if the NHS is to hit its targets, this has to change, but the NHS consumes millions of litres of hot water every year for a reason.
Heating water to high temperatures and flushing systems with water are pillars of water safety plans in healthcare environments up and down the UK.
The climate crisis is quickly becoming an issue for healthcare services
These are designed with patient safety as the number one priority, and any interventions to reduce carbon emissions or water consumption can be no different.
This is the nature of the challenge for water safety teams, and significant work is going into finding a viable solution from groups such as the Water Management Society.
However, a magic bullet is yet to emerge and the final answer is likely to be a combination of interventions that reduce energy and water consumption while retaining the safeguards that protect patients.
A previous issue of Looking Deeper (Issue 14, Autumn/Winter 2023), the journal of the Water Safety Forum and published by Armitage Shanks, explores some of these pressing questions, and their largely imperfect answers.
Alternative energy
The majority of water heated for use in healthcare environments is heated by natural gas, something that is a significant barrier to the NHS hitting its emissions goals.
One more promising option is heat recovery from wastewater
However, gas is used to keep water at temperatures needed to protect against waterborne pathogens – a flow temperature of 60°C and a return temperature of 55°C, increasing to 70°C if sampling has indicated an increased microbial risk.
As a result, any alternative heating system needs to be efficient, powerful, and cost-effective enough to hit these temperatures consistently, a high bar that many of the solutions proposed so far are struggling to reach.
Heat pumps are one of these potential solutions.
Regular heat pumps have a Coefficient of Performance (CoP) of 3–3.5, but high-temperature heat pumps required to achieve the required flow temperatures have a CoP of 2.0 or less, meaning the more sustainable solution would have huge electricity demands.
Moreover, the maximum output temperature of domestic-sized heat pumps is 55°C, casting further doubt on the ability of the technology to meet the demands of large-scale healthcare settings without the use of secondary heaters to boost water temperature, which will likely also come with significant electricity needs.
There is an acute need for the UK to work smarter with its water as a whole
The story is similar for solar power and point-of-use water heating, which could play an important part in the solution, but will likely not be able to provide the consistent, substantial power needed to meet the requirements of healthcare facilities.
One more promising option is heat recovery from wastewater, where heat is exchanged between hot waste water that runs through a heat exchanger and back into the gas or oil boiler that treats water with heat.
Such a system wouldn’t replace a gas or oil boiler, but it would drastically reduce its energy expenditure. Heat recovery from wastewater is a system that has seen success when put into practice on an industrial scale, despite coming at a high cost.
However, heat recovery could create issues for current valve designs, lowering the temperature to below the standards required for thermostatic mixers.
Any application of heat recovery systems would have to ensure that input temperature isn’t diluted, with patient safety the primary concern.
Tapping into greywater as a resource is another potential intervention
If heat recovery systems were implemented, products and product standards EN 1111 / EN1287 would need to be aligned to ensure the safety of end users if inlet temperatures are to be diluted at either cold or hot inlets.
Reducing flow temperature requirements would make many of these systems more viable, but this would require significant changes to existing NHS water safety guidelines, an unlikely prospect and a long process that would require significant testing of an alternative safeguard against contamination.
Chemical water treatments such as chlorination, UV light radiation, ozonation, and sliver stabilised hydrogen peroxide have been raised as potential alternatives, but these have their own challenges.
The potential for harmful byproducts and the need for additional monitoring are just two examples.
When a solution (or combination of solutions) does arise, significant testing and validation will have to be conducted before it is approved for use in healthcare settings, and robust guidance for design and construction, use and maintenance will need to be implemented with stakeholders to ensure it is water-tight.
Water economy
When it comes to using less water, the situation is more promising but there remain challenges to be overcome with potential interventions.
There was never going to be a cure-all for carbon emissions in the NHS
Healthcare settings use huge amounts of water in rigorous cleaning regimes but also as a resource to keep water systems moving and prevent opportunities for contamination from a build-up of biofilm.
There is an acute need for the UK to work smarter with its water as a whole, and the Government has set reduction targets accordingly.
Hitting these targets will take regulation and innovation in domestic settings, but the challenge is even greater in healthcare, given the vital role that moving water plays in protection from infection.
There is scope for optimisation of the flushing routine for little-used outlets to ensure that they are only flushed when needed for infection control with automatic flushing systems, rather than simply at regular intervals.
This would undoubtedly reduce water usage but would require enhanced monitoring and tracking capability to identify these outlets in the first place and ensure the leaner regime isn’t affecting water quality.
Healthcare settings use huge amounts of water in rigorous cleaning regimes
Tapping into greywater as a resource is another potential intervention, but also one that has serious limitations.
Greywater is leftover, untreated water from washing machines, bathtubs, and bathroom sinks. According to existing guidelines, greywater isn’t suitable for healthcare settings, but there are significant potential savings on offer if appropriate and safe use cases could be found.
Again, the process for leveraging greywater to flush certain toilets, for example, would require robust safeguards to ensure it didn’t pose a risk to patient safety and contamination to the surrounding supply.
To be implemented safely, greywater should be heavily managed and monitored to ensure there is no contamination of the drinking water supply in line with EN1717.
Making it happen
There was never going to be a cure-all for carbon emissions in the NHS, in particular for the emissions burden of heating water and the quantities of water used throughout healthcare facilities.
Any application of heat recovery systems would have to ensure that input temperature isn’t diluted
But the progress already made in since efforts began shows that a sustainable health service isn’t an insurmountable task.
A solution that reduces energy and water demands while maintaining patient safety as priority number one will likely be a patchwork of different interventions tailored for specific facilities working in unison.
This will require multidisciplinary collaboration and for water safety groups to continue their admirable and diligent work not just to keep water safety standards high, but also to lead in the development and implementation of best practice when new solutions do arrive.
