EXPLAINER | The process behind Archbishop Desmond Tutu's ‘water cremation’

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Archbishop Thabo Makgoba lays the ashes of Archbishop Emeritus Desmond Tutu to rest at the high altar of St George's Cathedral, with members of the Tutu family and Dean Michael Weeder of the Cathedral in the background.
Archbishop Thabo Makgoba lays the ashes of Archbishop Emeritus Desmond Tutu to rest at the high altar of St George's Cathedral, with members of the Tutu family and Dean Michael Weeder of the Cathedral in the background.
Benny Gool
  • Aquamation consists of cremation by water rather than fire.
  • The method, also known as alkaline hydrolysis, was introduced in South Africa in 2019.
  • It uses heat, pressure and water with a high alkaline level in the cremation process.

The body of Archbishop Desmond Tutu was reduced to dust by aquamation, a new cremation method using water that funerary parlours are touting as environmentally friendly.

Tutu, who vociferously campaigned for gentler stewardship of the earth, was cremated privately. His ashes were interred at St George's Cathedral in a private family service early on Sunday morning. Archbishop Thabo Makgoba of Cape Town laid the ashes to rest in front of the high altar of the Cathedral in a 30-minute service.

PICS | This is where Archbishop Desmond Tutu's ashes are buried in St. George's Cathedral

Like human composting, a technique of composting bodies with layers of organic material like leaves or wood chips, aquamation is authorised only in certain countries.

The introduction of aquamation to South Africa was introduced in 2019, reported Business Insider SA.

Aquamation, or alkaline hydrolysis, consists of cremation by water rather than fire.

The body of the deceased is immersed for three to four hours in a mixture of water and a strong alkali like potassium hydroxide in a pressurised metal cylinder and heated to around 150 degrees Celsius.

It is a saving of over 90% energy compared to using the traditional method. Also 20% to 30% more ash remains are returned to the family.

READ | We now bury the dead differently: cremations and grave recycling

The process liquifies everything except for the bones, which are then dried in an oven and reduced to white dust, placed in an urn and handed to relatives.

First developed in the early 1990s as a way to discard the bodies of animals used in experiments, the method was then used to dispose of cows during the mad cow disease epidemic, US-based researcher Philip R. Olson says.

In the 2000s, US medical schools used aquamation to dispose of donated human cadavers, before the practice made its way into the funeral industry, he wrote in a 2014 paper.

Tutu, who died on Boxing Day aged 90, was known for his modest lifestyle.

He left instructions that his funeral ceremony should be simple and without frills.

The anti-apartheid hero, whose funeral was held on Saturday, specifically asked for a cheap coffin and an eco-friendly cremation.

"The Archbishop was very clear on his wishes for his funeral. He wanted no ostentatiousness or lavish spending. He asked that the coffin be the cheapest available and that a bouquet of carnations from his family be the only flowers in the cathedral," according to the Archbishop Tutu IP Trust and the Desmond and Leah Tutu Legacy Foundation.

Q&A by Avbob: What aquamation is all about

How does the process actually work?

With aquamation, the beloved’s body is respectfully laid out in a receptacle, which is then placed in a sterile, stainless-steel chamber.

A combination of gentle water flow, moderate temperatures and alkalinity are then used to hasten the natural process, and all organic material is benignly broken down into its most basic building blocks.

At the end, the sterile process water is released for recycling – our bodies are made of about 63% water to begin with – and only the inorganic minerals remain. These are then lightly processed into powder and returned to the family in an urn.

Is acid used?

No. Aquamation uses a catalyst called alkali which, in fact, is the chemical opposite of acid. Alkalis are made from sodium and potassium salts.

Are the alkalis used in this process safe for the environment?

Yes. The water-based process uses a solution of 95% water and 5% alkali (a combination of sodium and potassium hydroxide). By the end of the process, the chemicals will have been completely absorbed and neutralised, and will no longer remain in the water solution.

Why is this seen as an environmentally friendly choice?

It’s a cleaner, kinder process. With aquamation, there is no direct emission of harmful greenhouse gases or mercury into the atmosphere. It is also extremely energy efficient, with more than 90% energy savings compared to flame cremation, and with just 1/10th of the carbon footprint.

What is the impact of the water usage?

The aquamation process uses as much water as a single household uses in a day. This includes the water used in the actual process, along with the final rinsing of the mineral remains and of the stainless-steel chamber.

READ MORE | Avbob introduces a new 'green' cremation - no flames, just water and heat

With burial space in urban areas worldwide becoming increasingly scarce and expensive, aquamation has obvious attractions.

Its advocates say water is a gentler way to go than flames and emits less greenhouse gases.

According to UK-based firm Resomation, aquamation uses five times less energy than fire, and reduces a funeral's emissions of greenhouse gases by around 35%.

Additional reporting by News24

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