Phosphorus is a chemical element. It is part of the backbone of DNA and thus contained in all animals and plants. It is one of the three primary macronutrients for plants. For agriculture, phosphorus is essential and it is, together with Nitrogen and Potassium, one of the three main constituents of fertilising products. Phosphorus for fertiliser production is mined from phosphorus rock. The main reserves of phosphorus rock lie in Morocco, West Africa and China. Scientists predict that in about 60 to 130 years peak phosphorus is achieved (in analogy to the peak oil). That means that the available resources of phosphorus will decrease, as only resource of phosphorus which are difficult to exploit will remain. As phosphorus which has been mined will be refund in food, it will also be refund in organic wastes and excreta. One alternative phosphorus resource is thus the reuse of treated and sanitised organic wastes and excreta as fertiliser.