Development of a Two-Stage Treatment Plant for Extensive Nitrogen and Phosphorus Elimination

Abstract

The report describes low-cost development and design of a two-stage wastewater treatment plant for 90,000 PE to achieve the highest possible degree of phosphorus and nitrogen elimination. The receiving water body of the treatment plant is a small watercourse fed almost exclusively by treated wastewater. A significant improvement in the water quality of this watercourse is planned. In particular, the performance of the wastewater treatment plant will need to be enhanced. The plant operator, the Erft River Board, organized a competition to attract solutions for an appropriate development of the plant from several consultants. Apart from embodying the concept of extensive wastewater treatment, designs were expected to preserve the existing infrastructure of the two-stage treatment plant as far as possible. Following selection of the most suitable design, the intended process technology is currently being tested in a pilot-scale plant. Planning envisages advanced wastewater treatment processes, including enhanced biological phosphorus removal, chemical precipitation/flocculation, nitrification and denitrification and combined coagulation/filtration. The pilot-scale investigations are carried out in close co-operation between the water authorities, the plant operators, the consultant, and a university institute of sanitary engineering. The paper presents the design and first results of the pilot-scale investigations in terms of the parameters BOD5, COD, phosphorus, ammonia and nitrate.