Ecological testing of products from phosphorus recovery processes - first results

Phosphorus is the essential nutrient with the lowest reserves and phosphorus can not be substituted by other elements. Therefore there is a great interest in using other available phosphate resources like waste water materials as source for phosphate fertilizers. Since 2004 the German Federal Ministry of Education and Research (BMBF) and the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) launched the funding programme "Recycling management of plant nutrients, especially phosphorus" 'which comprise the proving of novel and - up to now - not employed technologies and processes for recovery of phosphorus and if applicable further plant nutrients from waste materials - especially from municipal waste water and sewage sludge as well as from further applicable secondary raw materials. Thus the aim of the project in question is to examine the products generated in the funding programme as for their effect as fertilizer, for possible harmful impacts on the environment and for the technical qualities of the observed products. First results are presented which gives information about solubility of phosphorus and the concentrations of trace metals in the tested products. Further more the effect of the products on Phosphorus availability in soil and the uptake into plants was investigated.