DI Anna Stadler (Institute for Medicine and Biomechatronics, JKU) explained: "Leftover food is a high mass of organic energy."  Disposing of food waste and doing something useful with it can, however, be very costly. This is where mechatronic scientists can help: their method of "hydrothermal carbonization" converts biogenic substances – such as food waste – into hydro coal within a few hours.  DI Stadler added: "The pressure and temperature are comparatively low as well." A maximum of 250°C and 1-4 Mega Pascal pressure is required – both of which are inexpensive and feasible without much effort.

The process requires that the food waste be high in water content as the water serves as a reagent for the carbonization process. The process turns out perfect coal which can be directly recovered after drying and has a heating value of 15 per 25 megajoules per kilogram.

The process was developed as part of a collaboration effort between mechatronic scientists at the Institute of Environmental Economics and the Institute of Analytical Chemistry as well as an energy consultant who is also a restaurant owner.

The new procedure is particularly interesting for the food service industry as restaurants do not need to worry about where to store leftover food and removing the food waste. In addition, the conversion system is so simple that there is no need for special training or maintenance.

It is an absolute success story – medieval period alchemists could not have done any better.