Phosphorous are present in many anthropogenic waters with lakes and oceans as final recipients, where phosphorous cause eutrophication. The fact that large and important agriculture areas are placed close to the sea shores, poses a potential conflict between the need to keep the farmlands fertile and the possible phosphorus leakage from these areas. Small private owned sewage facilities is another major area causing emissions of phosphorous to lakes and oceans if no polishing is in use.

Hoganas is engaged in a partnership research project in Sweden (Project MINRENT) to explore the possibilities of purifying water from phosphorus, by using tailored filter materials made from industrial by-products from the Swedish steel and metal industry. The by-products included in the project are different kinds of slags. The partners in the project includes the Swedish steel industry as producers of filter material, manufacturers of filter systems and academia.

Lab and pilot-scale studies of by-products from Hoganas AB have shown that close to 100 % of phosphorus can be removed from water over time by using slag from steel and metal industry as filter material. These materials have also shown capacity to remove high level of nickel, zinc and copper from water.

When using by-products for water purification it will contribute to a decreased eutrophication. In addition, it will also lead to less use of virgin materials (including processing of these materials), that otherwise is used for this purpose.

At end of life, the sauterated filter materials can find use as either fertilizer and soil enricher, or as slag former in the steel and metal production.