A PETRI NETS-BASED PROCESS PLANNING SYSTEM FOR WASTEWATER TREATMENT

It is always challenging to simulate, debug or diagnose automated systems. The aim of this paper is to present the development of a convenient tool for reengineering the control system in a complicated industrial wastewater treatment plant. In this project, a PC-based Human-Machine Interface (HMI) in conjunction with Petri nets (PN) theory is adopted to develop and simulate the operational process for wastewater treatment. The resultant tool offers many advantages to the reality of the automated control world. It not only reduces the process reengineering time and the cost of error recovery, but also builds a panel of human interface for the process. The discrete event control sequence of wastewater treatment can be easily modeled and evaluated before its build-up. Furthermore, this PN-based system can be used as an online diagnostic tool when the wastewater treatment process is malfunctioning. That is, the presented PN tool provides an adequate means for of process development, simulation, performance evaluation, and quick online process diagnosis.