Upgrading of wastewater treatment plants to achieve advanced standards concerning nutrient removal

Abstract

According to the general wastewater administration rule, it is allowed for the single state authorities of Germany to make the minimal requirements on quality of wastewater discharge more restrictive then those given by the federal government. Schleswig-Holstein particularly has made extensive use of this rule in the past years. On addition of fluctuations due to tourism, industry or combined sewer system, the general criteria for the layout of wastewater treatment plants (WWTP) are presently unsatisfactory in order to meet these requirements. More detailed and comprehensive studies need to be carried out to fulfill these stricter demands. By illustrating four case studies of WWTP designs of size between 43,000 and 640,000 total number of inhabitants and population equivalents (PT), possible solutions will be presented. With the aid of land-registers, intensive measurement series and semi-technical and full scale experiments, design concepts including multi-stage and split flow treatment could be established.