Task Group on Good Modelling Practice (gmp) - guidelines for use of activated sludge models

The Task Group is officially hosted by the IWA Specialist Group on Systems Analysis and Integrated Assessment and and has full support from the Task Group on Mathematical Modelling for Design and Operation of Biological Wastewater Treatment.

Introduction

Mathematical modelling of activated sludge systems has become a widely accepted tool in the past decade, and is used for research, plant design, optimisation, training, and model-based process control. However, model results are only accepted in practice if the model predictions are reliable and the required effort for conducting the simulation study complies with the pre-defined goals. The quality of simulation studies can vary strongly depending on the project objectives, resources spent and expertise available. A great variety of approaches and insufficient documentation make quality assessment and comparability of simulation results difficult or almost impossible. To overcome these obstacles a general framework for the application of activated sludge models is needed.

Several guidelines have been developed during the last years. To merge their experience three European and one North American group decided to organize a workshop at the 4th IWA World Water Congress in Marrakech, Morocco:

• HSG – Hochschulgruppe, a group of researchers from German speaking countries
• STOWA - Dutch Foundation for Applied Water Research, The Netherlands
• BIOMATH – Department of Applied Mathematics, Biometrics and Process Control, Ghent University, Belgium
• WERF, Water Environment Research Foundation, North America

Goals of the Task Group

The goal of the group is to set up an internationally accepted framework to deal with the ASM type models in practice. This framework shall make modelling more straightforward and systematic to use especially for practitioners and consultants. Additionally, it shall help to define quality levels for simulation results, a procedure to assess this quality and to assist in the proper use of the models. The goals can be summarised as follows:

1. Set-up of an internationally accepted framework for activated sludge modelling, which should support the quality control of simulation studies.
2. The framework should be targeted towards practitioners and consultants and therefore has to include cost aspects.
3. The main task is to identify and classify different model application goals together with the required effort to obtain results with sufficient quality to meet the objectives of the study.

Outcomes

The framework will describe a methodology for goal-oriented application of activated sludge models demonstrated by means of a concise guideline about the procedure of a simulation study and some illustrative case studies. The case studies shall give examples for the required data quality and quantity and the effort for calibration/validation with respect to a defined goal.

The Task Group has full support from the IWA Specialist Group on Systems Analysis and Integrated Assessment and the Task Group on Mathematical Modelling for Design and Operation of Biological Wastewater Treatment.