OPERATIONAL RESULTS OF WASTE-WATER TREATMENT PLANTS WITH BIOLOGICAL N-ELIMINATION AND P-ELIMINATION

To an ever-increasing degree, it is nowadays demanded of treatment plants that they eliminate nitrogen and phosphorus from the waste water. Of the 81 treatment plants operated by the Lippeverband, a large number even now eliminate nitrogen although the percentage eliminated is still not optimal since, until recently, N elimination was still predominantly considered from the point of view of economy and stabilization of the degradation process. A further increase is definitely possible by means of an improved process and control technology. Phosphorus elimination can also be largely effected biologically. One of the plants provided with denitrification stages was appropriately retrofitted for this process. The results after two years of operation show that an optimum treatment efficiency can be achieved with a plant of this type.