FerroSorp® GW

Adsorbents based on iron hydroxide for the remediation and restoration of water bodies


The eutrophication of bodies of water is one of the most common water quality problems worldwide. Eutrophication, in example drinking water production, fish farming or swimming, often leads to efforts to improve the trophic situation. An excessive availability of phosphorus in water and sediment is seen as the main reason for increased biomass production and thus the eutrophication of water bodies. Phosphorus, however, also represents the limiting factor for eutrophication, i.e. a controlled reduction of the concentration of plant-available phosphorus can effectively limit eutrophication. A very effective way to eliminate phosphorus is binding it on the surface of iron hydroxide particles. To meet the different requirements regarding the treatment technology, a range of products under the name “FerroSorp® GW” has been developed, which can be used in both in-situ and ex-situ processes for the elimination of phosphate.


In a first step, in-water dissolved phosphate ions are absorbed onto the surface of FerroSorp® GW. In a subsequent reaction, the conversion to stable iron phosphate occurs according to the following equation:

equation FerroSorp GW

Product range

FerroSorp® GW is available in following standard grain sizes:



Depending on the grain size following applications for FerroSorp® GW are recommended:

  • Grain size 0 – 0.5 mm and liquid product: in situ-treatment of waterbodies
  • Grain size 0.5 – 2 mm: use in quick filters floating on water or stationary on shore
  • Grain size 2 – 4 mm: This product is available in special filter bags, which for example can be built into the water feed as a “nutrient trap”.

Use of FerroSorp® GW in a fresh water filter system here

Examples for the use of FerroSorp® GW in a fresh water filter system:


Advantages at a glance

  • High efficiency at low cost
  • Excellent loading rates due to a highly porous surface

In comparison with iron salt or aluminum salt solutions:

  • No change in pH in the treated water body
  • No addition of anions into the water body
  • Non-hazardous material – easy storage and handling