Environmental Research into Water Cremation
The Environmental Impact of Water Cremation
What does the research tell us?
One of the main reasons for growing interest in water cremation is its potential to reduce the environmental impact associated with funerals.
But describing something as “greener” is not enough.
A meaningful comparison needs to look at the whole process: energy consumption, emissions, materials, land use, water, transport and the treatment of remains.
Research reviewed by Durham University has compared alkaline hydrolysis — commonly called water cremation — with both traditional burial and flame cremation.
The findings suggest that water cremation has the potential to substantially reduce several of the environmental impacts associated with conventional methods.
Every funeral has an environmental impact
There is no form of funeral that has no environmental impact.
Burial may involve land, coffin materials, memorial stone, transport, cemetery maintenance and, in some cases, embalming.
Cremation requires fuel and high temperatures and produces emissions through combustion.
Water cremation uses electricity, water and alkaline compounds.
The important question is therefore not whether one process uses resources, but how their overall environmental impacts compare.
The environmental impact of traditional cremation
Modern cremation transformed funeral practice in Britain.
It initially offered important advantages over crowded cemeteries, particularly where land was limited.
But as environmental awareness has increased, attention has turned towards the emissions and energy consumption associated with cremation.
The academic research notes that concerns about crematorium emissions are not new. Environmental regulation of crematoria in Britain dates back at least to the Environmental Protection Act 1990, with particular concern historically surrounding pollutants including mercury.
High-temperature combustion can also produce gases including nitrogen oxides.
Research cited in Robinson’s paper demonstrates why reducing these emissions has become an increasing focus within the funeral industry.
Why water cremation is different
Water cremation does not rely on flame.
Instead, it uses alkaline hydrolysis: water, alkaline compounds and controlled conditions accelerate the natural chemical processes associated with decomposition.
Because there is no combustion of the body or coffin, the emissions profile is fundamentally different from flame cremation.
Research reviewed in the Durham paper cites estimates of approximately 90 kWh of electricity for the particular alkaline hydrolysis process examined and reports substantially lower energy consumption and carbon emissions than conventional cremation.
It also reports that dental amalgam containing mercury remains within the solid material, enabling it to be collected rather than being released through combustion.
Comparing environmental impact
One of the studies discussed in Robinson’s research is an independent life-cycle assessment by Dutch research organisation TNO.
The report examined four funeral technologies:
Burial
Cremation
Cryomation
Resomation / alkaline hydrolysis
Life-cycle assessment is important because it attempts to compare more than one isolated element of a process.
Instead, different environmental impacts are considered together.
The TNO analysis concluded that, under the assumptions used in its model, alkaline hydrolysis had a substantially lower overall environmental impact than either conventional burial or cremation.
That does not mean every individual funeral will produce precisely the same result.
The researchers themselves recognised that funeral choices vary considerably. A biodegradable shroud, for example, could make a burial less environmentally intensive than a funeral using resource-heavy materials.
The value of the study is therefore in comparing typical systems rather than claiming that every funeral has an identical footprint.
Lower energy requirements
Traditional cremation requires a chamber to reach extremely high temperatures.
Water cremation uses heat too, but the research reviewed by Robinson reports significantly lower overall energy requirements.
One estimate cited in the paper describes the process as using around one-eighth of the energy of cremation, although exact figures depend upon the equipment, energy source and operating conditions used.
This distinction is likely to become increasingly important as organisations attempt to reduce energy consumption and carbon emissions.
No flame
Perhaps the simplest difference is also the most fundamental:
There is no combustion.
Water cremation does not burn the deceased.
That means there is no cremation flame and no need to combust a conventional coffin alongside the body.
The process examined in Robinson’s research instead uses a biodegradable coffin or shroud.
This reduces some of the materials and combustion associated with traditional cremation.
What about mercury?
Dental fillings have historically been an environmental concern for crematoria because mercury can be released when amalgam fillings are exposed to the very high temperatures involved in cremation.
Water cremation does not burn dental amalgam.
Research cited in the Durham paper states that mercury-containing amalgam remains as a solid material that can be collected and safely recycled.
What about burial?
Burial has a very different environmental profile.
There is generally no direct combustion process, but a conventional burial may require:
land permanently or for extended periods;
coffin materials;
grave excavation;
memorial materials;
cemetery maintenance;
transport;
and potentially embalming.
This makes comparisons complex.
Natural burial can reduce several of these impacts significantly, particularly through biodegradable materials and lower levels of permanent infrastructure.
Water cremation should therefore not be presented as the only environmentally responsible funeral choice.
It is one of several ways in which families may seek to reduce the impact of a funeral.
How much water does water cremation use?
The use of water is an obvious and reasonable question.
The particular Resomation process considered by the research was reported as using approximately 1,500 litres of water per deceased person.
Viewed alone, that sounds substantial.
But environmental analysis needs to compare the complete lifecycle of different funeral methods rather than a single input.
Water use therefore needs to be considered alongside:
energy consumption;
carbon emissions;
land use;
materials;
air pollution;
and waste management.
The environmental question is consequently more complex than simply asking which process uses the least water.
What happens to the water afterwards?
Following alkaline hydrolysis, the mineral component of the bones remains separately.
The liquid contains the organic compounds that have been broken down during the process.
One concern historically raised about water cremation has been whether this liquid can safely enter normal wastewater treatment.
Research reviewed by Robinson describes UK testing undertaken with experts from Middlesex University working alongside Yorkshire Water.
The study concluded that the effluent tested presented no concern for sewer systems, wastewater treatment operations or receiving water quality, and was suitable for processing using standard wastewater treatment methods.
The research also reported that the tested liquid contained no DNA.
Is water cremation carbon neutral?
No responsible environmental claim should suggest that water cremation has no impact at all.
Electricity has an environmental footprint.
Water has to be supplied and treated.
The equipment must be manufactured.
Buildings need to be constructed and operated.
Transport remains part of most funerals.
For that reason, Aquatorium® believes the appropriate claim is not that water cremation is impact-free, but that research indicates it can offer a lower-impact alternative to conventional flame cremation.
A more sustainable funeral choice
Funeral traditions have always evolved in response to changing social needs.
In the nineteenth century, concerns about sanitation, overcrowded cemeteries and available land helped drive the development of modern cremation.
Today, climate change, energy consumption and sustainability have become increasingly important considerations.
Robinson’s research argues that these changing environmental priorities could play a similar role in encouraging interest in water cremation.
Water cremation therefore represents something straightforward:
another choice for families who want to consider the environmental consequences of what happens after death.
Water, not flame.
[Discover How Water Cremation Works]
Continue exploring
[Water Cremation vs Traditional Cremation]
[Water Cremation vs Burial]
[What Happens to the Water?]
[The History of Water Cremation]
Research source
The evidence discussed on this page draws principally upon Georgina M. Robinson’s 2021 academic review Dying to Go Green: The Introduction of Resomation in the United Kingdom. The article itself brings together evidence from a number of earlier environmental studies and should therefore be presented as a review of existing research, rather than as a new lifecycle assessment conducted by Aquatorium®.