1. General Model Information

Name: Activated Sludge SIMulation Program

Acronym: ASIM

Main medium: aquatic
Main subject: biogeochemistry
Organization level: Ecosystem
Type of model: not specified
Main application: education, research, decision support/expert system
Keywords: waste water, activated sludge systems,


Willi Gujer
8600 Dübendorf

email: willi.gujer@eawag.ch



ASIM (Activated Sludge SIMulation Program) is a simulation program, which allows for the simulation of a variety of different biological wastewater treatment systems: Activated sludge systems with up to 10 different reactors in series (aerobic, anoxic, anaerobic), including sludge return and internal recirculation streams, batch reactors, chemostat reactors, etc. The program allows for the definition of process control loops (simple proportional controllers and on/off type controllers) and dynamic simulation of load variation (diurnal load variation, temperature variation, variation of operational parameters such as aeration, excess sludge removal, recycle rates etc.). Data analysis is supported by the possibility to compare observed data with simulation results in easy to use graphic support routines. Simulated results may be exported to spreadsheets for further treatment.

A menu driven user interface with marginal help information, graphic support and simple file handling makes the program easy to use in class rooms, research and commercial applications.

The special feature of ASIM is, that biokinetic models (the different materials or components used to characterize the wastewater and the transformation processes with relevant stoichiometry and kinetics) may be freely defined, stored and edited by the user. This allows the researcher to develop his own specific model and it allows the student to learn modeling by stepwise increase of model complexity. Simple as well as complex models are distributed together with the program in the model library. The distribution diskette includes copies of the Activated Sludge Model No.1 and No.2 as proposed by the IAWQ Task Group for Mathematical Modeling for Design and Operation of Biological Wastewater Treatment.

Examples of the application of ASIM are documented in the following publications:

ASIM was developed as a teaching program, it serves today for research and consulting as well. The program may be copied and further distributed as long as nothing is charged for this service. If the program is used for commercial purposes, it is considered to be fair if a contribution of SFr. 1000.- is made towards the cost of developing such programs.

The ASIM package includes a batch version of the program, which allows for the simulation of complex problems. A simplified version requires less RAM and may be useful in teaching. If you order version 3.00 from the author (and pay a nominal fee) you will be informed about further developments.

ASIM Version 3.00 exists in English only. Hardware requirements are specified in the following order form.

Source of abstract: EAWAG, ASIM homepage http://www.eawag.ch/services_e/software/e_asim.html

II. Technical Information

II.1 Executables:

Operating System(s):

II.2 Source-code:

Programming Language(s):

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

W. Gujer and M. Henze 1991: Activated Sludge Modeling and Simulation, Wat. Sci. Tech., 24, Kyoto, pp 1011-1023.

W. Gujer and T. A. Larsen 1995: The Implementation of Biokinetics and Conservation Principles in ASIM, Wat. Sci. Tech, 31, No. 2, 257 - 266.

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: Juergen Bierwirth Fre Nov 3 16:56:44 CET 2000
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:39 CEST 2002

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