Process development for the production of a biobased fertilizer with metered nutrient release
Meat processing companies generate large amounts of waste that require complex and costly treatment based on national and European hygiene regulations. Usually this type of waste is processed in rendering plants (TKV) which require large amounts of thermal energy. The final products are either burned in waste incineration plants and cement factories or are limitedly used as an animal feed additive. Großfurtner GmbH, one of the largest slaughterhouses in Austria is the first company worldwide that is able to utilize large parts of its accumulated waste through a unique fermentation process in order to generate heat and power. Apart from the main product, which is biogas, also a side product, digestate, is produced during fermentation. Due to the relatively low nutrient density of the digestate - as it usually is the case in waste biogas plants – profitable application seems virtually impossible.
During the production process, additionally significant amounts of risk materials (category 1 and 2) as well as litter material arise, which only can be sent to rendering plants so far. In the course of project approach, the two aforementioned problems (expensive digestate exploitation and low-value waste) will be solved in a synergistic manner in order to generate a completely new and high value product with soil activating and soil-improving properties. This product not only shows a high nutrient density and storage stability, but also is expected to be largely free of odor and climate-relevant emissions. Furthermore, it even counteracts to climate change by a long-term carbon fixation in the soil. From the so far unused waste materials, the base product biochar (nutrient carrier) is obtained by pyrolysis. By varying the process parameters and by a targeted modification of the char surface with chemical methods, the base product is optimized in terms of quantity and quality of nutrients to be adsorbed as well as the maximum achievable water holding capacity.
The nutrients to be adsorbed are obtained from anaerobically processed slaughterhouse waste by means of an innovative low-temperature process.
In addition, pure water can be recovered that is able to replace expensive process water in the facility.
The resulting product will be extensively characterized, whereas the focus is set on toxic substances (European Biochar Directive) as well as on the quantity and quality of adsorbed nutrients and their bioavailability in soil. Nutricoal therefore enables to close the gap in terms of exploiting the entire waste material accumulated during the slaughter process in an innovative and sustainable way. Low-value waste material will be converted into a high-value biobased product. The main goal of the project is the development and adaptation of the individual process steps and the optimization of the entire process chain. This project represents a flagship in terms of waste recycling and product development not only for meat-processing industry, which generates in Europe up to twenty million tons of waste per year, but also for agriculture and the biogas industry.
FFG - Österreichische Forschungsförderungsgesellschaft
Universität für Bodenkultur Wien
AEE Institut für Nachhaltige Technologien
Next Generation Elements (NGE) GmbH