For a successful nutrient elimination in activated sludge plants the residue loads from the sludge treatment must not be neglected. In customary sewage treatment plants the residue load of nitrogen amounts up to 20%, however, hardly any phosphorus is recycled. A changed situation appears where the biological phosphorus elimination is concerned. Polyphosphates from the organisms are completely retro-solved in the anaerobic mesophilic sludge stabilisation. The liberated phosphate is, however, partly chemically-physically refixed. In the refixation the adsorption on solid matter-surfaces, the precipitation of struvit (MgNH4PO4 · 6H2O) and calcium phosphate, as well as the influence of zeolithes from detergents are involved. The phosphate concentration in putrified water is determined through the interaction of the various fixation processes. The processes were characterized in a laboratory-digestion reactor and in separate batch tests. The phosphorus residue-load through putrified water concerning sewage treatment plant intake amounts to 5 -10% at a common stabilisation of primary and excessive sludge and of the current sewage water composition in Switzerland. The residue-load through the thickening of the fresh sludge depends on the chosen process and can be minimised by means of a thickening of the excessive sludge.