Laboratory long-term upstream fixed-bed experiments were carried out to investigate the efficiency of phosphorus elimination with the effluent of a biological sewage treatment plant using crushed gas concrete. The development of the pH-value in the column outflow as well as the reaction kinetics was investigated. Furthermore, the phosphorus yield was balanced for phosphorus recovery and the calcium phosphate compounds generated were specified by mineralogical analysis methods. These activities were followed by a study with respect to the suitability of the material as raw material for the phosphate industry.