Dutch analysis for P-recovery from municipal wastewater

Abstract

There is a considerable practical interest in phosphorus recovery from water authorities, elementary P-industry, fertilizer industry and regulators in a number of countries. Due to a handful of full-scale plants worldwide, P-recovery can be seen as technically feasible. However, the economic feasibility of P-recovery from sewage can still be judged as dubious. The most important reason for this is that the prices of the techniques (in €/tonne P) are much higher compared to the prices of phosphate rock. In this paper an analysis is given to recover phosphate from municipal wastewater for the elementary P-industry Thermphos International B.V. and the fertiliser industry Amsterdam Fertilizers B.V. in The Netherlands. Several scenarios are evaluated and the end products of these scenarios are compared to the quality required by both industries. From a Dutch study it became clear that all end products from the final sludge treatment do not provide a good source of secondary phosphate. As a consequence of this, the most preferred possibility for P-recovery is to extract phosphate before sludge goes to the final sludge treatment. Different scenarios can be selected based on the position of P-recovery in the WWTP configuration, the type of P-recovery product, and the precipitation technique. Local conditions will determine which scenario is the most expedient. Because it is more realistic to judge a practical situation instead of theoretical estimations based on literature, some local situations have to be assessed in sufficient detail to gain more feeling for the expenses and possible savings of P-recovery. One important actor that should be involved in the process management around P-recovery, is the national government. Especially, the Government have the responsibility for sustainable development and should have attention for some stimulation of P-recovery in The Netherlands. Water authorities and the P- and fertilizer industry made already some good steps.