Mitigation of phosphate surplus from pig manure


For Dutch farmers, valuing pig manure is a major issue, since intensive livestock has caused a significant phosphate surplus in Dutch agriculture.

A local company has started operations wherein pig manure is collected from 70 farmers and mono-digested together with unborn manure, collected from slaughterhouses. The digestion process produces renewable gas for approx. 1,700 households. The digestate is separated in two streams. The phosphate rich stream is dried with waste heat and palletized into an organic phosphate turning into a rich fertilizer product, which is exported to low-phosphate regions in Europe. The other stream is processed in an on-site waste water treatment plant, resulting into clean water that is discharged to local surface water.

For 70 intensive pig livestock farmers, the practice offers a solution to process their manure surplus (required by Dutch law) into organic phosphate rich fertilizer pellets, which are transported to low-phosphate regions (closing the phosphate mineral loop).

The process is an example of closing the loop on economic and ecological sustainability for urgent challenges in the (national) agricultural sector. Through chain collaboration and high dedicated technology, this business model enables to create a stable economic opportunity out of (former) waste streams like pig manure, animal by-products and food residues

Nikos Kyriakoulis