(479e) Bond Graph Modeling of an Integrated Biological Wastewater Treatment System

Compared with abstract pure mathematical representation of a system and rough engineering drawings, bond graph theory provides a unique graphical view based on energy interactions between interdependent domains. Bond graph representation sits in the middle between equations and schematic block-graphs, combining most of the advantages from both extremes. Bond graphs have been shown to be effective for mechatronics system, mech-hydraulics system and electro-chemical system modeling.

In this study, bond graph theory is extended to include the biochemical domain. The traditional bond graph can be used to describe the flow of energy between two integrated biological reactors ? a packed bed reactor in series with a tubular reactor--that is part of NASA's advanced wastewater treatment system for human long-duration space flight missions to moon and Mars. Beyond the biochemical domain, bond graph theory also would be applied to model the hydraulics between the packed bed reactor and the tubular reactor, the mechanics for the peristaltic pump drives and valves supporting the hydraulics and finally the electronics of the control system. With the bond graph, a general description of the integrated biological reactor system including the biochemical, mechanical, hydraulic, and electronic information will be used for system control studies and process fault-detection/isolation (FDI) applications.

In this work, modified bond graph theory will be developed and presented for the integrated biological reactors. Its merit will be demonstrated on applications of control and FDI.

References

J. Lefevre and J. Barreto, ?A Mixed Block Diagram Bond Graph Approach for Biochemical Models with Mass Action and Rate Law Kinectics?, J. Franklin Inst. Vol. 319, No. 1/2, pp. 201-215, 1985.

D. C. Karnopp, D. L. Margolis and R. C. Rosenberg, ?System Dynamics, Modeling and Simulation of Mechatronic Systems?, Third Edition, Wiley, New York, 2000.

J. Thomas and B. O. Bouamama, ?Modeling and Simulation in Thermal and Chemical Engineering, A Bond Graph Approach?, Springer, New York, 2000.