Water Cremation UK: 5-step Guide to Alkaline Hydrolysis

Water Cremation UK: 5-step Guide to Alkaline Hydrolysis

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Organising Alkaline Hydrolysis should be easy and low-stress. Learn about this environmentally-friendly alternative to cremation in our ease-to-use guide. 



Water Cremation UK: A 5-step Guide to Alkaline Hydrolysis



What is Alkaline Hydrolysis?

Alkaline Hydrolysis is an environmentally-friendly alternative to cremation or burial. The process can be referred to as a water cremation, green cremation or flameless cremation. Aquamation, Resomation and Biocremation are registered brand names for the same process. 



How Does Alkaline Hydrolysis Work?


Alkaline hydrolysis uses a mix of potassium hydroxide and water at a very high temperature to break down the soft tissue in a body. The mix is made up of 5% Potassium hydroxide (also known as lye or caustic soda) and 95% water, creating a high-alkalinity liquid. The high temperatures and pressure mimics the slow process of natural decomposition. The end result is that water cremation breaks down all proteins, including DNA, into a sterile liquid. 


After water cremation, all that is left behind is:

  • bones 
  • any artificial implants or prosthetics the deceased may have had 


After the alkaline hydrolysis process, what is left of the bones is pure calcium phosphate. This is extremely brittle and it can be converted into white dust. The ‘ash’ that results from this can be returned to the deceased’s family. They can choose to scatter, bury or store this ash as they wish.



What is the Full Alkaline Hydrolysis Process?


The process of water cremation is similar to conventional cremation, in that the deceased is brought to the facility after the family have said goodbye. The deceased is placed in a stainless steel container inside a high-pressure Resomator machine. The vessel is sealed and filled with an alkaline mixture of 95% water and 5% potassium hydroxide. This mixture will have a pH level of 14. 


The liquid is heated at high pressure to around 160°C. Water cremation mimics the natural process that occurs when a body breaks down through decomposition, but the high temperature and pressure speeds up the process from a number of years, to a number of hours. The high pressure means that the air above the water is kept at 160°C, thus maintaining a sterile environment. The liquid is washed over the body in a cycle until all soft tissue is dissolved.


Once this Resomation process is complete, the liquid and the bones are completely sterilised (pathogen-free). 



How long does the process of water cremation take?

The Resomation or  Biocremation process should take 2-3 hours. The resomator is a high-pressure vessel with temperatures reaching over 160°C . The high pressure in the chamber ensures that the air above the water is also sterilised. This guarantees that no pathogens survive the process, and leaves the bones sterile and pure white. The Resomation process is a comparable alternative to cremation in terms of time.


Aquamation, on the other hand, uses a machine with a lower pressure and temperatures around 98°C. The Aquamation cycle must run for around 14 hours to complete the process of decomposition and sterilisation. 



What happens to the remains after a water cremation?

After the Resomation process, the sterile liquid is drained from the machine and cooled. It contains the most basic building blocks of any living organism: amino acids, peptides, sugars and salts. However, this liquid does not contain any DNA or genetic material. After filtration, it can be disposed of in a garden of remembrance. It can also be disposed of in a standard surgical-waste manner.


Once the liquid has been drained, the bones are rinsed and carefully removed from the vessel. They are allowed to air-dry for a few days. The bones are extremely brittle at this point. As with conventional cremation, they are then placed in a cremulator. After this, the pure white ‘ash’ is returned to the next of kin.


Resomation is a favourable alternative to cremation because the process has a similar turnaround time, and the result is similar: the next of kin receives their human ashes. Families can choose to keep these remains in an urn, bury them, or disperse them, according to their beliefs and the deceased’s wishes.


Any non-protein based materials in the body will not dissolve during the Resomation process. This includes teeth, dental fillings, artificial implants, pacemakers and jewellery. These items are collected after the process is complete. They can be returned to the family or appropriately recycled.



What are the benefits of a water cremation?

Alkaline hydrolysis is known as ‘green cremation’ because it is more environmentally-friendly.


Water cremation is a better alternative to cremation for a number of reasons:

  • it uses 10% of the electricity required for traditional cremation
  • no mercury or toxic emissions are released into the atmosphere
  • pacemakers and prosthetics do not need to be surgically removed
  • jewellery, gold teeth and implants can be disposed of after the process is complete
  • all soft tissue is dissolved, leaving pure white bone
  • the powdered bone is returned to next of kin, just as human ashes would be after cremation
  • families receive about 20% more “ashes” than from a conventional cremation


Some people also view Resomation as a kinder and more dignified option. They find water to be a more peaceful alternative to cremation


Water cremation also has certain benefits over burial:

  • a body is decomposed in a matter of hours, compared to the 8 – 12 years it takes for a body to decompose in a traditional coffin
  • no embalming chemicals are leached into the ground, thus protecting ground water from toxins
  • bodies do not take up space in graveyards, which can be important in overcrowded cities
  • a water cremation does not require a wood or steel casket, nor a gravestone



What is the History of Alkaline Hydrolysis?


Alkaline Hydrolysis was originally a method used for animal carcasses. It has now become an environmentally-friendly option for processing human remains. It is still a relatively new option, but it is growing in popularity around the world.



Alkaline hydrolysis for animal disposal:

The Alkaline Hydrolysis process was first developed in 1888 as a process to decompose animal matter for use as plant fertiliser. After the BSE epidemic in Britain resulted in millions of cattle burned in pyres, the EU Parliament approved Alkaline hydrolysis as a method to dispose of animals. It was found to be a more hygienic and environmentally-friendly way to decompose of contaminated animals that had been culled. It also guaranteed the destruction of pathogens, whereas burning or burying the carcasses still carried the risk of infection. 


In the 1990s, two lab technicians developed a way of disposing lab animals using the alkaline hydrolysis technique. They started a company called Waste Reduction by Waste Reduction Inc.

The alkaline hydrolysis machines they produced for animal disposal were very large and could hold several cows at once. Alkaline hydrolysis machines like this can process hundreds of pounds of animal waste products and carcasses a day. This includes waste from meat processing plants, as well as contaminated wild deer and elk that have been culled. Companies like Bio-Response Solutions, produce smaller machines to process domestic pets and individual animals.



Alkaline hydrolysis as an alternative to cremation:

In 2007, a Scottish biochemist called Sandy Sullivan developed a processing machine that could be used as an alternative to cremation. He developed a vessel, which he called the Resomator. It held a single human body and was capable of handling high temperatures and pressure. The vessel brings the alkaline liquid up to 160°C  at high pressure, meaning the liquid and air above it are completely sterilised. Within four hours, this machine dissolves the soft tissues of a human body, and sterilises the bones. Once the cycle is completed, the liquid is cooled and disposed of. The bones are rinsed, dried and crushed in a cremulator. Sullivan called the process, and his company, Resomation. The first Resomator was installed at a water cremation facility in Florida in 2011. 


Subsequently, other water cremation companies have developed their own alkaline hydrolysis machines. Bio-Response Solutions started off making alkaline hydrolysis machines for veterinary colleges and pet cremation companies. They now also produce more cost-effective alkaline hydrolysis machines for human remains. 


Aquamation machines, too, are a more cost-effective option. These vessels work with a lower heat and lower pressure. They rely on a process whereby an alkaline solution is heated to 98°C, before it flows gently over the body for up to 14 hours. Though this cycle takes much longer to complete, these machines are more popular for small funeral homes. The founders of Resomation have been very vocal about these slower alkaline hydrolysis machines. They claim this slower process is not dignified and does not guarantee sterility.


In 2010, the cremation society of North America changed the definition of cremation to include alkaline hydrolysis. Their definition is based on the fact that the body is reduced to bone fragments and returned to the next of kin. Though accepted by the cremation society, water cremation is only legal in about 20 US states. The funeral industry has been slow to embrace alkaline hydrolysis. Generally, interest in the process is growing overall, as people become aware of the environmental benefits.



What is the Legal Status of Alkaline Hydrolysis in the UK?


In the UK, Alkaline hydrolysis is considered a safe way to dispose of contaminated animal remains after mass outbreaks of bird flu, or foot and mouth disease. It is also a legally accepted method for pet cremation. 


Alkaline hydrolysis for human remains is currently legal in the UK, provided the correct health and safety guidelines are adhered to. There are still a few factors delaying its widespread use across the country. 




The high cost of the alkaline hydrolysis machines make them a difficult purchase for small, family-run facilities. A Resomator can cost about £330 000 to buy. The Aquamation and Biocremation machines are cheaper to purchase, but their cycles take much longer to complete and thus fewer bookings can be processed in a day. As the popularity of alkaline hydrolysis grows, the cost of the machines should come down, making it a more affordable option.



Water treatment:

The other difficulty with alkaline hydrolysis is getting buy-in from local water treatment authorities. Scientific studies have found the water to be completely sterile and free of DNA material. Yet many people are still uncomfortable with the idea of adding dissolved human remains to the water system. In March 2020, the first “waste water consent to discharge” was given to a Resomation facility in Yorkshire. This allowed the facility to discharge the liquid from the water cremation process into the sewer system, and for it to be processed with standard water treatment methods. 




As it is a relatively new method, water cremation is not yet widely accepted in the UK. Some people are uncomfortable with the process of dissolving a body in liquid. There are also religious concerns from the Catholic Church that the process is undignified. However, it is growing in popularity as people become more aware of the environmental impacts of both conventional burial and cremation. Some people also view Resomation as a more dignified and peaceful alternative to cremation by fire. 



How Much Does a Water Cremation Cost in the UK?


Currently, a Resomator machine costs around £330 000 to purchase. This means that investing in the Resomation process will be quite expensive for the average water cremation facility. However, the cost to run a Resomator is lower than the cost of running a conventional crematorium. For this reason, water cremation in the UK should cost around the same as a conventional cremation, and perhaps even less, as it grows in popularity. In the UK, it costs around £1600 for a direct cremation, and about £4000 for a cremation with a simple funeral service. Water cremation services will cost around the same.


At Fenix Funeral Directors, we offer a range of green funeral plans. We would be happy to assist you with any questions you have around alternative funerals and cremation services. If you are considering alkaline hydrolysis as a burial option, our advisors are here to help arrange this for you in the UK. 





What remains do the family get back after a water cremation?

The family receive a container of sterile white powder. This ‘ash’ is the result of the Resomation process, which leaves behind the deceased’s bones as pure calcium phosphate. There is usually around 20% more bone ash retained after an alkaline hydrolysis cycle, compared to the remains from a conventional cremation.



Can you have a funeral if you have a water cremation?

It is completely viable to plan a normal funeral ceremony before a water cremation. The process is thus the same as a conventional cremation: 

  • after the service, the deceased is transported to the facility
  • the body is removed from a temporary casket 
  • it is wrapped in natural fibers, or undressed
  • the body is placed inside the vessel 
  • the process runs for its allocated time


Once the Resomation or Aquamation process is complete, the bones are dried, turned into powder, and returned to the next of kin. According to the wishes of the family, these ‘ashes’ may be scattered, buried or kept in an urn. If the family decide not to have a funeral service before the water cremation, they may choose to hold a memorial service at a later date.



Is Resomation a green alternative to cremation?

Resomation, or alkaline hydrolysis, is a green cremation option. It uses 10% of the electricity needed for a conventional cremation, and it does not release carbon and toxins into the atmosphere. If you are interested in alternative funerals and cremation services, please contact us (insert hyperlink) at Fenix Funeral Directors. Our caring advisors will take you through the different options to suit your exact circumstances, in the most environmentally-friendly way – if you so wish.