Hydro cremation, scientifically known as alkaline hydrolysis, is an alternative method for final disposition that uses water and alkali chemicals rather than fire to process human remains. This water-based process mimics natural decomposition, but accelerates the timeline from years to mere hours within a specialized chamber. Often called water cremation or aquamation, the technique is gaining traction as an environmentally conscious choice. The method reduces the body to its basic chemical components, leaving behind only bone fragments that are then returned to the family.
How the Process Works
The process begins by placing the body into a stainless steel chamber, a pressurized, sealed vessel. This chamber is then filled with a solution that is predominantly water (typically 95%) combined with a strong alkali chemical, such as potassium hydroxide or sodium hydroxide. The highly basic solution creates an environment with a pH level of approximately 14, which initiates the breakdown of organic material.
The mixture is heated to a moderate temperature, often around 320 degrees Fahrenheit (160 degrees Celsius). Elevated pressure is simultaneously applied within the chamber to prevent the water-alkali solution from reaching its boiling point. This combination of heat and alkalinity accelerates the chemical reaction of hydrolysis, gently dissolving soft tissues, fats, and organs.
Depending on the specific temperature and pressure used, the entire process can take between four and sixteen hours, with many facilities reporting an average of six to eight hours. Once the cycle is finished, the chamber contains a sterile liquid effluent and the inorganic bone structure of the deceased. This effluent is a nutrient-rich solution composed of salts, sugars, amino acids, and peptides, which is safely returned to the wastewater treatment system.
The remaining bone fragments are allowed to dry after being saturated by the water solution. These brittle calcium phosphate pieces are then reduced to a fine powder using a specialized machine, a step similar to what occurs in flame cremation. This bone powder, which families receive in an urn, is the final physical remnant.
Key Differences from Flame Cremation
The primary difference between hydro cremation and flame cremation lies in the energy source and the temperatures used. Flame cremation requires a crematory retort to operate at extremely high temperatures, ranging from 1,400 to 1,800 degrees Fahrenheit, utilizing natural gas or other fossil fuels. Hydro cremation uses a water-alkali solution heated to a much lower temperature, typically around 300 to 350 degrees Fahrenheit, relying primarily on electricity to run the machinery.
This disparity in temperature affects the time required for each process. Flame cremation is generally faster, completing the reduction in approximately two to four hours. The lower-temperature process of alkaline hydrolysis typically requires a longer duration, with most cycles lasting between six and eight hours.
A noticeable distinction exists in the final appearance and volume of the processed remains returned to the family. The intense heat of flame cremation can cause chemical changes in the bone structure, resulting in a gray or off-white color and a coarser, ash-like texture. Remains from hydro cremation are typically a brighter, purer white color and have a finer, more consistent texture due to the lower temperature and water-based process. Furthermore, the volume of bone material returned is often significantly greater, up to 20% to 32% more than what is produced by a flame-based process.
Availability, Cost, and Environmental Impact
The availability of hydro cremation is highly dependent on local regulations, and its legality varies significantly by state and country. As a more recently adopted technology, it is not yet as widely accessible as flame cremation, though it is currently legal in over twenty states in the United States. Due to the need for specialized equipment and infrastructure, the service is often offered in a limited number of funeral homes, affecting its availability outside of major metropolitan areas.
When considering the cost, hydro cremation is often positioned similarly to flame cremation or slightly higher, with prices typically ranging from approximately $1,300 to over $4,500. This price point generally makes it a more affordable alternative compared to a traditional full-service burial. The final cost is heavily influenced by regional market factors, including local regulations, the cost of utilities, and competition among providers.
The environmental benefits of hydro cremation are a primary factor driving its adoption. The process uses substantially less energy than flame cremation, with estimates suggesting a reduction in energy consumption of up to 90%. This decrease in energy use translates to a lower carbon footprint.
A key benefit is the elimination of direct air emissions and pollutants, such as the mercury vapor released from dental amalgam when subjected to the high heat of a flame crematory. The sterile liquid byproduct also captures the carbon from the body, preventing its release into the atmosphere. This liquid is allowed to be reintegrated into the natural water cycle through municipal treatment facilities.