What is alkaline hydrolysis?

• Scotland has legalised alkaline hydrolysis (water cremation), an environment-friendly alternative to cremation or burial.

• This process is already in use in some countries including the United States, Australia, Ireland, Canada, and South Africa.

• The Scottish government consulted on the issue in 2023, with 84 per cent of those who responded supporting the introduction of hydrolysis.

• The Scottish government is not suggesting hydrolysis replaces or displaces traditional methods of burial or cremation in any way.

• It gives an option for people interested in alternatives to burial or cremation. 

What is alkaline hydrolysis?

• Alkaline hydrolysis is a method of disposal of human remains using hot water with the addition of potassium hydroxide, or sodium hydroxide, or a mix of both. 

• The body is wrapped in a silk or woollen shroud, or other biodegradable material, before being placed into a pressurised chamber and heated to up to 150°C. 

• The combined action of heat, water, and potassium hydroxide, causes the body’s organic substances to dissolve in the liquid. 

• This fully automated process takes two to ten hours, depending on the temperature and on the weight of the body to be processed. 

• In addition to heating the liquid, a complete cycle involves various cooling and rinsing steps.

• After the process is complete and the bones and any implants removed, the remaining liquid is cooled before being moved to a treatment tank. 

• The liquid produced as a result of alkaline hydrolysis is slightly alkaline. 

• It includes compounds such as sugars, amino acids and fatty acids, nitrogen, phosphorus, and potassium hydroxide. 

• Remains can be returned to next of kin, similarly to ashes following cremation.

• International evidence suggests hydrolysis is more sustainable than traditional cremation, which uses large amounts of natural gas.