HD is a major devourer of water resources. For reference purposes, one dialysis cycle consumes as much water as 3.5–4 people per day at the centre.8 Ultrapure water is generated at the water plant, the efficiency of which depends on various factors: on the one hand, the supply water (conductivity, salinity, hardness, suspended elements and seasonal variability); and on the other hand, the design of the treatment and pretreatment plant (some designs are more efficient than others for saving waste water and the shelf life of the reverse osmosis membranes). The technology used can achieve a recovery rate of 50%–75%.9 Finally, the efficiency of the HD session depends on the size and operation of the centre. Larger facilities, even though they use a higher total amount of water, can be more efficient since almost all of the water is used for treatment. In small centres, part of this water usage, especially if the centre dialyses on alternate days, is used for ring washing and regeneration of some elements of the treatment plant, even if dialysis is not carried out that day. By way of example, in a study conducted in 12 of our centres over three years (2019–2021), with an average of 10,541.5 ± 7264 (range 756−22,436) HD sessions per year, large centres (>10,000 sessions per year) consumed a greater amount of water than small ones (<10,000 sessions) (5910 vs 2437 m3 year) (P < .001). However, water usage per HD session was significantly lower in large centres than in small ones (367.3 vs 589 l/HD (P < .001).10

Two of the consequences of the climate crisis are variations in temperatures and weather patterns. Sensitive regions, such as the Mediterranean basin, will be affected by an increase in the number and intensity of heat waves, which will contribute to periods of drought with storms and floods.11 A 15% decrease in rainfall is projected according to the most conservative models, which will significantly affect the planet's water resources12 and, as a direct result, dialysis techniques. Each conventional HD session (duration of four hours) can require up to 500 l of mains water,13 with only a third being used directly as dialysate (500 ml/min × 4 h = 120 l, not counting disinfection water). For on-line haemodiafiltration (OLHDF), the usage of replacement fluid needs to be added to these figures. In addition, maintaining the water plant also entails additional usage, as we have already mentioned, washing and regeneration processes, keeping the water in the ring in constant motion, disinfection, etc.

The indicator that measures the energy expenditure of an HD unit is electricity usage (kWh)/session. The average annual electricity usage of the centre can be equated to the estimated daily usage of approximately 2.5–3 households (estimated average usage of 9 kWh/day per household).14 The energy expenditure in an HD centre is multifactorial. In addition to the usage of the monitors themselves (between 1.5–3 kWh/session), other costs are involved in this type of treatment that need to be calculated,15 such as the energy usage of air conditioning, lighting and other equipment (computers, storage refrigerators, water treatment or osmosis systems, thermal disinfection, automation of centralised concentrates and patient televisions, etc.), as well as transportation.

The production and distribution of materials used in haemodialysis is a multifaceted process with significant environmental implications. Transportation from manufacturing plants to distribution centres and, ultimately, to healthcare facilities, requires significant energy expenditure and logistical coordination, contributing to carbon emissions and air pollution. The decision in a unit to use individual acid canisters for all patients or to use centralised acid for the majority and canisters for those requiring more personalised treatment can have a major environmental impact. Materials used in haemodialysis predominantly include plastics, polymers and other synthetic compounds, reflecting the strict requirements for biocompatibility, durability and sterility.

The waste generated in the haemodialysis process is classified according to its nature (Fig. 1):

• 1

  Group I (waste similar to urban waste): paper and cardboard (product boxes, packaging, office paper), containers (plastic and metal, medical device wrappers, empty concentrate canisters), organic waste, glass and other unclassifiable waste (the so-called remainder).

• 2

  Group II (non-specific medical waste): dressing material, bandages, plasters, blood-stained single-use tissue, secretions, gloves, lines and used and emptied haemodialysers, as well as all waste not classifiable as hazardous.

• 3

  Group III (medical waste with biological hazard): which would include blood and blood products in liquid form, live and attenuated vaccines, anatomical waste without sufficient entity, cultures, infectious agents, animal waste for research, as well as sharp and cutting material, such as needles, scalpel blades and slides.

• 4

  Group IV and Group V (cytotoxic material with mutagenic, carcinogenic or teratogenic properties, biohazardous medication, chemicals).

Fig. 1.

Classification of waste generated in haemodialysis.

(0.35MB).

Waste generation is linked to both quantity (kg/HD session) and type of material. Of particular interest is waste that is reusable or easily recyclable with a view to extending their life cycle or reducing the carbon footprint resulting from their management, which depends on the waste group and its subsequent processing (recycling, reuse, landfill or incineration). The bulk of the waste generated by HD will usually fall within groups I and II, and to a lesser extent group III. Nonetheless, we should not forget the huge amount of paper consumed in HD units, which can be minimised.

Transporting this material from manufacturing plants to distribution centres, and ultimately to healthcare facilities, requires considerable energy expenditure and logistical coordination, contributing to carbon emissions and air pollution. The same applies to transportation used by staff and patients.

In order for any activity to be carried out, it needs an input of energy, materials, consumables and raw materials, etc. Therefore, in dialysis there will always be usage and emissions generated in proportion to the scale of the activity.

It should be noted that any measure or action to not use any electricity or water, or generate any waste (zero emissions) is completely unfeasible. In the short term, the best policy is to minimise energy and water usage, and waste generation (which will never be zero). In the long term, moving towards a zero-emissions policy makes sense through the use of offsetting systems (photovoltaic panels, implementation of CO2 capture systems, planting of trees, extended manufacturer responsibility).

The need to focus actions towards a more environmentally friendly model in the field of dialysis has been clearly stated in the literature.16–18 In order to make a gradual transition towards a more sustainable treatment, indicator measuring systems, environmental impact and efficiency analysis should be introduced as an initial step, according to the needs and limitations of each centre (Table 1).

The energy efficiency of HD is related to the electricity usage of the monitor, the water treatment plant and thermal disinfection, as well as the air conditioning and lighting of the facilities. Both air conditioning and lighting must meet optimal standards of well-being for both healthcare personnel and patients, ensuring the maximum possible efficiency in the use of energy resources.

In order to be more energy efficient, the following measures can be considered, always taking into account the optimal conditions of well-being for staff and patients:

• a

  Lighting.

One of the simplest measures is the installation of energy-efficient LED lights and motion sensors that activate the centre's lighting devices to reduce electricity usage in general and in unnecessary periods (night, non-active days).

• b

  Air conditioning options.

Royal Decree-Law 14/202219 stipulates that heating and air conditioning in public buildings should not exceed 21 °C in winter or be below 26 °C in summer. For patients on dialysis, it should be considered that changes in the temperature of the dialysate can increase or decrease their body temperature. For the well-being of these patients, it is important to either adjust the temperature for their comfort or use blankets (which also entail a cost of manufacturing, periodic washing and replacement). Other measures include proper compartmentalisation and insulation of rooms, the use of materials to minimise dissipation losses and the use of highly-efficient air conditioning systems.

• c

  Green energy generation.

The possibility of installing solar panels or photovoltaic solar energy to cover part of the centre's demand should be evaluated.

• d

  Cold disinfection.

An easy strategy to implement is the use of monitors that allow cold disinfection (37 °C), as opposed to high temperature disinfection (80 °C), but this will depend on the chemicals involved.

• e

  Energy reuse.

A novel alternative is the installation of generating turbines in the different stages of the reverse osmosis (RO) system, which allow part of the energy consumed to be recovered through mechanical energy.20

Centres consume water in healthcare activities as well as in healthcare-related tasks, such as cleaning, bathrooms, hand washing and dishwashing. There are a number of strategies that could be put in place to optimise dialysis water usage (Fig. 2):

• a

  Rationalising dialysis bath flow.

Fig. 2.

Strategies for optimising consumption in haemodialysis.

(0.47MB).

While there is a downward trend, practices whereby the dialysate flow is between 700−800 ml/min21 (including usage for its generation) are still common. Given that climate change will have an impact on drought, emphasis must be placed on optimising water usage. For some years now, there has been an insistence on rationalising the dialysis flow at 500 ml/min, even in OLHDF techniques. Higher values demonstrate only a marginal contribution, both in the dialysis dose (Kt)22,23 and in the clearance of uraemic toxins.24,25

• b

  Modification of priming and flushing strategies, as well as washing and regeneration processes of the pretreatment elements and the ring.

• c

  Assess the number of water softeners needed based on the hardness of the water (fewer water softeners save water and the salt required for the process).

• d

  Water reuse.

Possibility of using the water discarded at various stages of its use (in the reverse osmosis [RO] system or from the haemodialyser effluent fluid):

• •

  Water rejected by the RO system: there are systems that achieve reject water recycling rates of 50%–75% by passing it through osmosis again. The waste water meets quality standards26,27 and can be used for other purposes: supply for toilets (WC), steam for sterilisation28 or irrigation of garden areas.29 In other innovative trials, waste is used in a horticulture and aquaponics system.30

• •

  Effluent liquid from monitors: there is reluctance to reuse it owing to its high salinity and content of phosphates, nitrates and microorganisms.31,32 However, standard waste water treatment processes allow the recovery of nutrients with high fertiliser value for the agricultural sector.33,34 Nonetheless, these measures are not without cost.

  • a

    Scalable water plant that generates sufficient quantities of water for the number of patients in the unit.

  • b

    Water plant automation.

Ensuring that the absence of chemical and microbiological contamination is a priority for all HD units. All components of the system are involved in this process: water supply, arrival at the monitor, design of the treatment plant, etc. The implementation of digitisation and remote control in water plants, compared to conventional advanced sensor technology, can increase energy expenditure, but reduces water usage and the number of trips by technical staff (from 486 h to 92 h), substantially reducing the environmental impact.35

• a

  Other actions: plumbing and sanitation maintenance, review and updating of quality standards, as well as introducing new technologies and optimised dialysers, dry cleaning techniques, installation of aerators on taps and reduction of toilet water usage.

Waste reduction and management and its proper segregation must be an objective in dialysis units. This can be achieved by:

• •

  Optimising usage.

• •

  Expiration control.

• •

  Cleaning of lines and dialysers to make them suitable for municipal recycling.

• •

  Prioritising sustainable suppliers.

• •

  Reducing reliance on paper thanks to digitisation and bidirectional connection between monitors and electronic medical records (if paper is used, it should ideally be recycled).

• •

  Using centralised systems (lower usage of plastic canisters).

In terms of economic and environmental sustainability, kidney transplant is currently the most sustainable renal replacement therapy (RRT) option,44 accounting for 54.45% of RRT patients in Spain according to data from the 2021 Dialysis and Transplant Report.45

A recent Italian study46 suggests that home HD methods (especially unassisted home HD) are a viable option with a lower environmental impact for subjects living in low population density areas where the transport of subjects and professionals has a high impact on CO2 emissions. However, there is considerable room for improvement for increasing the implementation of home-based techniques, and further research is needed to demonstrate that these techniques do indeed reduce the carbon footprint significantly compared to in-centre HD.

It is essential to raise awareness among professionals in order to minimise the environmental impact of healthcare activities. All medical societies and scientific organisations urgently need to undertake useful and long-lasting educational initiatives, where digital innovation opens the door to a more sustainable future.

Countries such as the United Kingdom and the Netherlands have already launched national initiatives. The European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) has created a specific committee, the “Sustainable Nephrology Task Force”, whose aim is to raise awareness about sustainability and kidney disease, and has organised its 60τη congress as a hybrid event to reduce the impact of travel. It has also promoted Forestami, a project launched by local authorities to plant three million trees by 2030. The International Society of Nephrology has also launched its global initiative (Global Environmental Evolution in Nephrology and Kidney Care [GREEN-K]) with the aim of promoting sustainable and resilient renal care.47 In Spain, the carbon footprint was measured at the last two Spanish Society of Nephrology (SEN) congresses and the results showed a total scope of 97 tons of CO2 equivalents and 64.5 kg of CO2eq/participant at the Granada Congress (52nd edition, 2022).

It is important to define activities that reduce environmental impact, such as waste packaging. When choosing new dialysis equipment or materials, their sustainability or the development of programmes to reduce, reuse and recycle materials must be considered.48

In general, the measures adopted in HD to reduce environmental impact have an initial cost of investments, data analysis, etc., which is not always recovered. Even so, some of these measures may lead to at least a partial recovery of the initial cost in the medium-long term, such as, for example, the use of centralised systems instead of canisters for more efficient dialysis fluid consumption, improvements in air conditioning to reduce expenditure on energy usage, or appropriately sized water plants to optimises the cost of water usage. However, future studies that include an analysis of the economic impact of these measures are needed.

Dialysis tenders must take into account the reality of treatment and technology, updating requirements that have become obsolete and that may entail unnecessary costs, both economically and environmentally (e.g., requiring water plants with certain characteristics that are oversized with respect to the centre's needs). It would be interesting if dialysis tenders, in both the rates and their valuations, took into account the investment that an environmental improvement entails.