Alkaline Hydrolysis & Water Cremation Options

To prevent additional carbon exhausting directly into the atmosphere, Interra Green Burial by Mueller Memorial offers alkaline hydrolysis as an ecological alternative to traditional flame cremation.

What is water cremation? 

Water cremation, or alkaline hydrolysis, is a human disposition method where water, heat, and an alkaline solution accelerate tissue breakdown, eventually resulting in dry, fine cremated remains (ashes) which are returned to the family. Alkaline hydrolysis is the scientific name but it is also many other names such as, water cremation, flameless cremation, green cremation, wet cremation, chemical cremation, aqua cremation, hydro cremation, liquid cremation, aquamation, or resomation.

The body is laid onto a cot connected to the alkaline hydrolysis machine. The cot is inserted into the large vessel and sealed, then a lye solution of 95% water and 5% strong base (sodium hydroxide and/or potassium hydroxide) are introduced. Moderate temperature (177C or 350F) and fluid flow accelerate the natural reduction of soft tissue to its elements. The liquid is removed, leaving only the dense bone material, very similar to what remains after flame cremation. 

This remaining inorganic bone material is dried and processed into what most people would recognize as cremated remains, the only differences being remains from alkaline hydrolysis are a brighter white color and have about 20% greater volume. 

Potassium hydroxide (lye) is a strong base that occurs in nature through the leaching process from wood ashes after forest fires. People have made soaps by burning wood, extracting hydroxide compounds from the ashes, and then filtering out the particles. However, the leaching process from wood is not efficient for large-scale production of potassium hydroxide so modern production utilizes easily accessible fibrous biomaterials. Sodium hydroxide (also called lye) is very similar in function but is produced through the electrolysis of brine, a salt water solution.

The aquamation process takes roughly 6-8 hours. By comparison, flame cremation takes roughly 1.5-3 hours at about five times the temperature.

After the alkaline hydrolysis process is complete what remains is an inert liquid rich with peptides, sugars, amino acids, and captured carbon which is harmlessly released into the wastewater system. The inorganic solid bone material is processed and returned to the family as fine hydrolyzed remains or “ashes,” similar to those of traditional cremation.

The liquid that remains after aquamation is sterile, non-toxic and a welcomed addition to the waste water system. In fact, some states allow the remaining liquid, with its peptides, sugars, amino acids, and captured carbon to be reclaimed and repurposed as fertilizer. 

We do not have a system for direct liquid recapture at Interra, but the liquid produced is sent to the Blue Lake Wastewater Treatment facility, where it is separated then either turned into fertilizer or processed and carried on as clean water back into the Minnesota River bound to join the mighty Mississippi in Mendota, MN.

Flame or traditional cremation uses combustible gasses, usually natural gas, to heat the cremation chamber, or retort, to a temperature of 1400-1600 degrees fahrenheit to allow rapid disintegration of the tissue. Water based cremation uses a more moderate temperature of 350 degrees using roughly 90% less natural gas than flame cremation. Aquamation also captures, or sequesters, the carbon from the body in water rather than emitting it into the atmosphere. 

The human body is made up of 18.5% carbon. Flame cremation exhausts carbon from the body directly into the atmosphere along with the exhaust from the natural gas used to heat the retort. According to the U.S. Energy Information Administration, about 117 pounds of CO2 are produced per million British thermal units (MMBtu) equivalent of natural gas. And according to the Cremation Association of North America (CANA) the average cremation uses 2,379,915 BTUs. This means that 278.46 pounds of carbon from natural gas plus the carbon from the body are emitted directly into the atmosphere.

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Alkaline hydrolysis does require about 350 gallons of clean water per service. However, with Interra that water is returned to the water system, destined for the Blue Lake Wastewater Treatment plant. Once there, organic elements are removed from the wastewater, dewatered, dried and pelletized for use as an agricultural fertilizer, under a public-private partnership between MCES and the New England Fertilizer Company (NEFCO). An additional solids treatment process called anaerobic digestion produces methane gas that helps power the solids drying equipment. All clean water that remains carries on to join the Minnesota River.

Aquamated remains are returned to the survivors for whatever permanent memorialization they choose, they can be buried in a cemetery, kept in an urn, scattered on land or in water, transformed into a gemstone, or launched into space (yes, that’s really a thing). Anything that someone would do with flame cremation remains can be done with aquamated remains.

Yes, with some help. Aqumated remains, like flame cremated remains, are non-nutrient and contain a high level of calcium phosphates and salts, not ideal for growing plants. So, as with any cremated remains you cannot place the remains at the root of a tree without treating or supplementing it first. 

The Living Urn has science-based solutions for incorporating cremated remains into a tree planting, but with some research you could likely do it yourself. Alternatively at a memorial forest like Better Place Forests in the St Croix Valley of Minnesota you can scatter the ashes at the base of an existing tree you purchase in a preserve setting.

Generally the cost for aquamation is more than flame cremation, because the process takes longer, and the equipment is more costly. However, currently Interra Green Burial by Mueller Memorial is charging the same amount for water cremation as Mueller Memorial does for flame cremation to encourage more people to consider the more eco-friendly cremation option.

Disposition laws are determined by the individual states and as of May 2023 alkaline cremation is legal in, Alabama, Arizona, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Idaho, Illinois, Kansas, Maine, Maryland, Michigan, Minnesota, Missouri, Nevada, North Carolina, North Dakota, Oklahoma, Oregon, Tennessee, Utah, Vermont, Virginia, Washington, West Virginia, Wyoming.

Yes, alkaline hydrolysis is legal and available in Minnesota. In 2003 Minnesota was the first state in the US to legalize water cremation, led by the highly respected Mayo Clinic which used View Source alkaline hydrolysis cremation as their primary means of disposition for their anatomical bequest and research program donors.

Not in accordance with the March 2023 statement from the Committee on Doctrine, United States Conference of Catholic Bishops titled, “On the Proper Disposition of Bodily Remains”. It is the official position of the Catholic Church that, “[Aquamation] does not show adequate respect for the human body, nor express hope in the resurrection.” 

That is the policy of the Church not the policy of the provider. Interra will provide aquamation services, without judgment, to anyone who requests them and return all remains to the family to do with as they wish, including interment in any Catholic or other cemetery.

If you are searching for “water cremation MN,” you’ll find that Interra Green Burial by Mueller Memorial offers aquamation services to the entire seven county Twin Cities metro area.

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