What is Water Cremation (Alkaline Hydrolysis / Aquamation)? A Guide

Also known as alkaline hydrolysis, water cremation, or aquamation is a gentler alternative to traditional flame cremation, offering a more environmentally friendly approach to the process. Water cremation uses water, alkaline chemicals, heat, and pressure to accelerate the natural decomposition of a body. This method has gained popularity in recent years for its reduced carbon footprint and a different way of treating human remains.

Steps in the Alkaline Hydrolysis Process

The water cremation process consists of a few key steps:

1. Preparation: The preparation of the body is similar to that of traditional cremation. However pacemakers and other implants do not need to be removed unlike with flame cremation. Clothes are removed.
2. Positioning: The body is placed in a pressurized vessel known as a hydrolysis or aquamation chamber.
3. Solution Added: A mixture of around 95 percent water and 5 percent alkali, a type of chemical that is highly basic (as opposed to acidic), is added to the chamber. The chemical used is typically potassium hydroxide or sodium hydroxide.
4. Heating: The chamber is heated to around either 200 °F or 300 °F (depending on the rating of the machine)​. This temperature is maintained, but the mixture is not boiled.
5. Hydrolysis: Over several hours, the heat, pressure, and alkali solution break down the body’s organic materials. This leaves behind only inorganic compounds, primarily bone ash, and a sterile liquid. The higher temperature process takes 6-8 hours, the lower temperature process takes 18-20 hours.
6. Cooling and Rinsing: After the process is complete, the chamber is cooled and rinsed, leaving only bone fragments and the sterile liquid.
7. Processing of Bone Fragments: The bone fragments that remain are composed of calcium phosphate. They are processed into a fine ash, similar to what is left after flame cremation.
8. Disposal of Sterile Liquid: The sterile liquid, which is essentially a nutrient-rich solution of amino acids, peptides, sugars, and salts, can be safely released into the sewer system or used as a fertilizer. In most cases in the US, liquids are released in the sewers for later processing by water treatment plants.
9. Return of Ashes: The ashes can be returned to the family in an urn or other container in a similar way to the ashes from a traditional cremation.

Comparison to Traditional Cremation

Aquamation and traditional flame cremation differ in several key aspects. Aquamation uses a gentle process involving water, heat, and alkali to dissolve the body, which tends to be more environmentally friendly but also more expensive than traditional cremation. Flame cremation, on the other hand, uses intense heat to reduce the body to ash, which is generally less expensive and more widely available. The final remains from aquamation are more voluminous and finer in texture compared to those from flame cremation.

Aquamation is generally more expensive than the cheapest flame cremation options and prices vary across states.

The decision between the two often comes down to personal preferences, budget, and environmental considerations.

Science Behind Water Cremation

Unraveling the Process: How Water Cremation Works

Aquamation works based on a chemical process called hydrolysis. Hydrolysis involves the breaking down of a compound by a reaction with water. In the context of aquamation, the human body is placed in a pressurized vessel with a mixture of water and alkali, typically potassium hydroxide or sodium hydroxide. The vessel is then heated to a high temperature (around 200 °F or 300 °F / 93 °C or 150 °C) which helps speed up the hydrolysis process. Because of the pressure, the water is able to reach a high temperature without boiling.

Over a period of several hours, the heat, pressure, and alkali solution work together to break down the body’s organic materials, leaving behind only inorganic compounds, primarily bone ash, and a sterile liquid. The sterile liquid, which is essentially a nutrient-rich solution of amino acids, sugars, and salts, can be safely disposed of into the sewer system or even used as a fertilizer. The remaining bone ash, similar to what’s left after flame cremation, can be returned to the family if they wish.

The Chemistry of Alkaline Hydrolysis: A Closer Look

Alkaline hydrolysis is a chemical reaction that occurs when a compound is exposed to a solution of water and an alkali. Alkalis are substances that have a high pH level, above 7, and can neutralize acids. In this case, the alkali (potassium hydroxide or sodium hydroxide) breaks down the body’s proteins, fats, and carbohydrates into simpler compounds.

What’s left after the process is a small amount of bone ash and a sterile liquid that’s rich in nutrients. The bone ash can be given to the family, similar to traditional cremation, while the sterile liquid is safe to be released into the sewer system or used as a fertilizer.

History of Aquamation

The genesis of alkaline hydrolysis traces back to the late 19th century, having initially been developed as a means to safely dispose of animal carcasses. Its transition into usage with human bodies is more recent.

Alkaline hydrolysis was patented by an Englishman, Amos Herbert Hobson, on December 25, 1888 as a method for processing animal remains into plant food​. Although this method was beneficial to farmers, it was not yet applicable to the funeral industry, which at the time was primarily concerned with slowing down rather than accelerating decay.

Albany Medical College colleagues Gordon I. Kaye and Peter B. Weber revisited the technique of alkaline hydrolysis in 1994. They adapted it for the safe disposal of animals used in research. They founded the company WR2. They installed their first “tissue digester” machine at Albany Medical College in 1992 and sold their first system for processing human remains donated for medical research to Shands Hospital at the University of Florida in 1995​²​.

Over the next decade, they installed more than 75 alkaline hydrolysis machines in various institutions, including the Mayo Clinic. Their company WR2 went bankrupt in 2006 following an unsuccessful expansion attempt in Europe. Former president and CEO Joseph Wilson later formed Bio-Response Solutions, and Sandy Sullivan, who had headed the company’s subsidiary in Europe, formed Resomation Ltd. in Scotland the following year​²​.

In 2010, funeral director Jeff Edwards started offering aquamation services to his customers, marking the first time the method was used in a funeral home setting. However, after performing 19 processes, Edwards faced regulatory challenges and was denied permits for body disposal via alkaline hydrolysis. Despite a legal challenge, as of 2023, the process is still not permitted for disposing of human remains in Ohio​.

Water Cremation of Desmond Tutu

Interest in water cremation spiked in early 2022 following the death of Desmond Tutu, who opted for alkaline hydrolysis. The South African Anglican bishop and social rights activist, passed away on December 26, 2021, in Cape Town, South Africa. He made headlines as one of the most high-profile individuals to opt for a water cremation. His ashes are interred in St. George’s Cathedral in Cape Town. Although acceptance of water cremation varies among religious communities, Desmond Tutu, being an Anglican, was in favor of the process.

Legal and Regulatory Aspects

State Approvals

In the United States, water cremation is not yet legal in all states. However, 25 states have already approved its use for human remains, including California, Florida, Illinois, Minnesota, Oregon, and Maine. Regulations and terminology may vary across states, with some referring to the process as dissolution, chemical disposition, or alkaline hydrolysis.

International Acceptance

While water cremation is growing in popularity in the United States, its acceptance and legality vary internationally. Countries may have different regulations regarding the use of alkaline chemicals, and some may not yet recognize water cremation as a viable option. Countries where aquamation is legal include Australia, some Canadian provinces, Ireland, Mexico and South Africa.

Pet Cremation

Water cremation is legal for pets in all states in the USA.

Alternatives to Water Cremation

Human Composting

Also referred to as natural organic reduction, human composting is another green burial option that is gaining popularity. This method transforms remains into a nutrient-rich soil that can be used to nurture the growth of plants and trees.

The process involves placing the body in a specially designed vessel, along with materials like wood chips and straw, to aid in decomposition. After approximately 30 days, the vessel contents will have broken down into a fertile soil that can be returned to the family or used in designated memorial landscapes.

Human composting is considered to have a smaller environmental impact than traditional funerals and even water cremation, as it doesn’t use chemicals or release harmful emissions. However, this method is currently available only in a few locations, as it is a relatively new funeral option.

Natural Burial

Natural burial, sometimes referred to as green burial or eco-friendly burial, is another option to consider. This method encourages the natural decomposition process, returning the body to the earth in a more environmentally friendly manner than conventional cremation and traditional funeral practices.

In a natural burial, the body is prepared without the use of harmful chemicals or embalming fluids. It is typically placed in a biodegradable casket made of renewable materials or wrapped in a simple shroud. The grave site is chosen to have the least impact on the surrounding environment, allowing nature to take its course.

While natural burials may not be as widely known or available as traditional funerals, they provide an alternative that can ease your environmental concerns and offer a more serene resting place.

Further Questions Relating to Aquamation