Realisation of the EU Directive 91/271/EWG in Germany technical and economic effects from the perspective of an operator of large wastewater treatment plants.

In the Federal Republic of Germany, the requirements on the effluent quality which wastewater treatment plants (WWTPs) with a design value larger than 100,000 PE must achieve in regard to the parameter Nanorg were increased by a national regulation on 01/08/2002. The reason for this action was a pending threat of the European Court because of the insufficient realisation of the EU Municipal Wastewater Directive (91/271/EWG). The report at hand describes the consequences of such an increase of the requirements for operators of WWTPs, using the example of Emschergenossenschaft and Lippeverband. The currently applicable demands in Germany are compared to those valid on a European level, and the current construction and performance state of the WWTPs operated by Emschergenossenschaft and Lippeverband is presented. The secure compliance with the increased requirements necessitates optimisation measures, but also construction measures; these are described in regard to their technical realisation and the prospective costs.

Elimination costs for different wastewater compounds.

The present report presents the system and discusses the results of the cost calculation for the reduction/elimination of different wastewater and sludge compounds. These costs were calculated for different types of processes at 102 wastewater treatment plants of Emschergenossenschaft/Lippeverband and Aggerverband. Comparing enhanced biological phosphorus removal and precipitation, one of the results indicates that in general the costs for elimination of one kilogram of phosphorus are lower in the plants in which only chemical precipitation is used for P reduction. Further results of the cost calculation will be presented with a discussion of their possible influence on planning decisions.

Remote control system for the operation of 65 WWTPs.

The present report discusses the monitoring system for approximately 340 facilities for water management of the Emschergenossenschaft and Lippeverband. It is based on the operation control system of the wastewater treatment plants (currently 61) and the pumping stations of the Lippeverband, which has been created since 1985. For the near future, the integration of the plants of the Emschergenossenschaft including storm-water tanks is scheduled. The current connection ratios of the WWTPs which are to be monitored vary between 500 and 1,940,000 Population Equivalents. The data recorded at each plant are transmitted to the allocated catchment area centre and then to the district centres. The encompassing monitoring centre serves the integrated control of all plants. The comprehensive remote control is managed through the presentation of relevant plant-type-specific system parameters. The investment costs of approximately 33,000 Euros/plant and annual costs of 9,400 Euros/plant stand against a considerable increase of the operation safety and the reduction of manpower.

Modelling of full-scale wastewater treatment plants with different treatment processes using the Activated Sludge Model no. 3.

In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical Modeling for Design and Operation of Biological Wastewater Treatment was presented. The model is used for simulation of nitrogen removal. On the basis of a new calibration of the ASM 3 with the easy degradable COD measured by respiration simulation runs of this paper have been done. In 2000 a biological phosphorus removal module by the EAWAG was added to the calibrated version of ASM 3 and is now serving the current requirements for modelling the enhanced biological P-removal. Only little experiences with different load situations of large-scale wastewater treatment plants were made with both new models so far. This article reports the experiences with the simulation and calibration of the biological parameters using ASM 3 and the EAWAG BioP Module. Three different large-scale wastewater treatment plants in Germany with different treatment systems will be discussed (Koblenz: pre-denitrification; Hildesheim: simultaneous denitrification with EBPR; Duderstadt: intermediate denitrification with EBPR). Informations regarding the choice of kinetic and stoichiometric parameters will be given.