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This paper describes a method to decrease the additional measurement effort during a model calibration/verification to create reliable models for plant optimisation. The method is based on the deterministic processes creating the dry weather inflow to municipal treatment plants, which can be described by a simple influent composition model. This method was applied to two wastewater treatment plants of Lippeverband and the usability is indicated by the good correlation between routine online effluent measurements and simulation results. This paper presents one of these applications, the case study WWTP Dorsten. The resulting model is used to analyse the current plant performance, to analyse bottlenecks and to develop future improvements of operation and control of this plant. A selection of control options is demonstrated. [ABSTRACT FROM AUTHOR]

The selector activated sludge (SAS) systems are known to prevent excessive growth of filamentous microorganisms responsible for bulking sludge, but these systems were hardly ever modelled. This study aimed to develop a model capable of predicting rapid substrate removal in the SAS systems. For this purpose, the Activated Sludge Model No. 3 (ASM3) was extended with three processes (adsorption, direct growth on the adsorbed substrate under aerobic or anosic conditions). The modified ASM3 was tested against the results of batch experiments with the biomass originating from two full-scale SAS systems in Germany. The endogenous biomass was mixed with various readily biodegradable substrates (acetate, peptone, glucose and wastewater) and the utilisation of substrate (expresses as COD) and oxygen uptake rates (OURs) were measured during the experiments. In general, model predictions fitted to the experimental data, but a considerable number of kinetic (5) and stoichiometric (2) parameters needed to be adjusted during model calibration. The simulation results revealed that storage was generally a dominating process compared to direct growth in terms of the adsorbed substrate utilisation. The contribution of storage ranged from 65-71% (Plant A) and 69-92% (Plant B). [ABSTRACT FROM AUTHOR]

In the end of the year 1999 a new concept for Hamburg's wastewater treatment plants was commissioned to cope with the additional load of 250,000 PE which has been connected to the existing plant serving 1.85 million population equivalents. The new concept consists of an additional tank for the storage of sludge liquor to avoid peak nitrogen concentrations in the effluent of the plant. This solution has been developed within a study assessing a wide range of concepts with costs between initial €100 million and the final construction costs of €1 million. Here the dynamic simulation showed to be a very efficient planning tool. Within the first three years of operation the chosen solution showed to be able to fulfil the requirements. In 2002 the concept has been improved by a few more measures, mainly the equipment of one of the storage tanks as a SAT tank for further cost effective nitrogen removal. For a further improvement of the treatment capacity additional measures are planned to be carried out within the next years. [ABSTRACT FROM AUTHOR]

This paper shows how the dynamic simulation of municipal wastewater treatment plants can be used for assessing the performance of a plantunder different legal requirements. In this study, the situation is described, when it was uncertain, how the requirements of the German law (ARAN 199 1) would be adapted to the requirements given by the EC-directive concerning urban wastewater treatment (EC directive, 1991). The requirements of these two are compared to each other. A simulation study is described, in which the future results of a plant to be extended am calculated for the period of one year. It is shown that, concerning the effluent concentrations of ammonia and total nitrogen,this plant will be able to meet both laws. (c) 1998 IAWQ. Published by Elsevier Science Ltd [ABSTRACT FROM AUTHOR]