Resource overview

Broad bean shells

© Ronja Einberger | University of Hohenheim

Nowadays, broad beans are mainly used as cattle feed. If they are processed into food, the skin remains. Dried, this can be kept for a long time.

Availability: approx. 2,000 t per year

Ammonium sulphate solution (ASL)

© Ronja Einberger | University of Hohenheim

Product from the nutrient recovery of biogas plant fermentation residues. After the separation of fibres and phosphorus, a liquid remains, which is heated to approx. 50°C. The nitrogen escapes as ammonia, which is then sprinkled with sulphuric acid to form ASL with approx. 9% nitrogen and 8% sulphur. ASL can be used as a fertiliser, among other things.

Birch bark

© Ronja Einberger | University of Hohenheim

Birch bark can be used as fuel or building material. It is also used as an adhesive or in naturopathy.

Availability: approx. 2,000 t per year

Biogas fermantation residue fibres (fine)

© Ronja Einberger | University of Hohenheim

Separation product from the biogas plant. After the coarse fibres have been separated from the fermentation residue, the fine fibres are then separated in a further step. This is done with the help of a spiral press with a 0.06 mm gap width of the sieves. The result is a very small-structured material.

Biogas fermentation residue fibres (coarse)

© Ronja Einberger | University of Hohenheim

Separation product from the biogas plant. After the fermentation process, the substrate is treated with sulphuric acid in a two-stage process. This leads to a pH reduction. This causes nitrogen and phosphorus to go into solution and the organic matter can be separated. After this acidification, the coarser fibres are separated using a spiral press with a 0.4 mm gap width of the sieves. The solids produced here are relatively coarse-fibred and rich in nutrients.

Fly ash from nut shells

© Ronja Einberger | University of Hohenheim

The production of nut oils and fats for the food and animal feed industry produces nut shells that are normally incinerated by the factories for their own energy needs. This combustion produces this quite homogeneous fly ash from nut shells, free of impurities.

Availability: approx. 2,500 t per year

Pomegranate peel

© Ronja Einberger | University of Hohenheim

Pomegranate peels are produced during the processing of pomegranates. In some cultures, the peels are already used in nutrition, medicine and cosmetics due to their high antioxidant content.

Availability: approx. 200 t per year

Oat husks

© Ronja Einberger | University of Hohenheim

The husks are a residue from oat processing in the food and feed sector.

Availability: approx. 2,000 t per year

Cocoa shells

© Ronja Einberger | University of Hohenheim

Cocoa shells are a by-product from cocoa processing. So far, many applications are known, such as an additive to animal feed, fertiliser and soil conditioner, or as a substitute for microplastics in the cosmetics industry.

Availability: approx. 10,000 t per year

Olive pomace pellets

© Ronja Einberger | University of Hohenheim

Olive pomace is left over when olives are processed into olive oil. The pomace consists of the residues of olive pits and shells. Olive pomace oil is sometimes extracted from olive pomace using chemical processes.

Availability: 10,000 t per year

Plant-based charcoal from cocoa shells

© Ronja Einberger | University of Hohenheim

Continuous industrial pyrolysis processes degas and carbonise cocoa shells to produce a highly active and absorbent plant carbon. So far, plant-based charcoal has been used, among other things, for the production of Terra Preta and as a soil conditioner in the agricultural sector. Research is also being conducted on plant-based charcoal in the area of animal and human health. There is a need for research for industrial applications, e.g. could it possibly be used as a substitute for soot?

Availability: approx. 4,000 t per year

Plum stones

© Ronja Einberger | University of Hohenheim

The plum stones are in chopped form and accumulate as residues during fruit processing.

Availability: approx. 400 t per year

Phosphorus salts

© Ronja Einberger | University of Hohenheim

Product from the nutrient recovery of biogas fermentation residues. After all organic matter has been separated, phosphorus salts are precipitated by adding lye and milk of lyme. Due to the increased pH value, phosphorus combines with magnesium, calcium, potassium and other elements and forms crystals. After the crystals have sunk, the phosphorus-containing sludge is pressed out in a chamber filter press. The question now is how this phosphorus fertiliser can be used further (pelletisation, granulation, mixing with other materials, etc.).

Sunflower hull pellets

© Ronja Einberger | University of Hohenheim

The processing of sunflower seeds produces large quantities of hulls. These have so far been used, among other things, as bedding for animal stalls, as their properties are very similar to those of straw pellets and granules.

Availability: approx. 10,000 t per year

Sugar beet molasses

© Ronja Einberger | University of Hohenheim

Molasses is a viscous sugar syrup that is a by-product of sugar refining. Up to now, molasses has been used as a feed in animal breeding due to its high sugar and protein content. Sugar beet molasses is also used as a raw material for the production of baker's yeast.

Availability: approx. 20,000 t per year