Explainer: Desmond Tutu was not cremated; he was aquamated

The ashes of South African spiritual leader Archbishop Desmond Tutu were buried at dawn on Sunday in a Cape Town cathedral.

Tutu had asked to be interred behind the pulpit at St George's Cathedral.

Despite his status as an icon of the anti-apartheid movement, the archbishop wanted a humble send-off in a pine coffin without extravagant spending on funeral services.

Tutu’s body underwent aquamation, the last act of this champion of the environment.

So, what is aquamation?

It is an increasingly popular and environmentally friendly alternative to traditional cremation methods, using water instead of fire.

With aquamation, or "alkaline hydrolysis", the body is immersed for three to four hours in a mixture of water and a strong alkali, such as potassium hydroxide, in a pressurised metal cylinder and heated to around 160 degrees Celsius.

Water, alkaline chemicals and heat are used to accelerate the decomposition process that takes place in nature.

The body is loaded into a stainless-steel vessel and filled with a mix of 95 per cent water and five percent alkali.

The mix is heated to around 160 degrees Celsius and gently circulates for four to six hours.

Aquamation vs cremation

By comparison, traditional cremation uses temperatures as high as 870 degrees Celsius and takes about two hours.

According to the Cremation Association of North America, only bones are left at the end of both aquamation and cremation.

From there, the bones are broken down further into a fine powder or dust and placed in an urn.

One of the greatest benefits of aquamation is its minimal impact on the environment.

With aquamation, there is no direct emission of harmful greenhouse gases or mercury into the atmosphere. Bio-Response Solutions says that the process doesn't use any fossil fuels and is 90 percent more energy-efficient than standard cremation.

History of aquamation

First developed in the early 1990s 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.

Aquamation was introduced in South Africa in 2019, reported Business Insider SA.