Utilisation of used diatomaceous earth

In this area we cooperate with SF-Soepenberg GmbH (Link), one of whose specialist areas is the recycling of used diatomaceous earth.

The "Düngemittelverordnung“ (fertilizer ordinance) permits the use of diatomaceous earth as a raw material for the production of fertilizers or soil additives. Based on analyses carried out since 2000, the recycling company has measured a diatomaceous earth content in the filtration residue of 18.4 %. The proportion of crystalline silica with a diameter of less than 50 µm is between 0.06 and 0.09 %. These values result from internal calculations and depend on the premix and use of different diatomaceous earths. Regular external analyses are below the detection limit. Requirements from the “Düngemittelverordnung” with regard to particle size are achieved through agglomeration using starch. There are no impurities with heavy metals or other solids. The last revision of the “Düngemittelverordnung” has just been completed without any changes as regards diatomaceous earth recycling. The labelling obligations are complied with.

There is therefore nothing to prevent future agricultural use.

Soepenberg organises the sale of the diatomaceous earth sludge and recycles it in the following manner:

  • Agricultural use as a soil additive (direct use or use for the treatment of liquid manure);
  • Utilisation of used filtration diatomaceous earth as a covering material in the steel industry instead of rice husk ash;
  • Utilisation in its dried state for pest control in henhouses or to control storage pests (in organic farming)

The recycling company recommends that breweries collect diatomaceous earth sludge in a tank to enable clean, odourless storage. In this way, transportation can also be optimised. The used diatomaceous earth is collected from the breweries in special vehicles and treated according to its intended use.

New recycling paths and possible applications are being investigated and developed.