Challenges

The project posed a number of challenges that required a combination of skill, knowledge, and creativity to implement solid solutions. One of these was the size and complexity of the database required to handle the data acquisition for the plant's expansion.

A total of 5,000 data points, 5,000 I/O connections, 2100 annunciated alarms, and more than 200 monitor screens comprised the end result. Additional programming was required to provide local dynamic data exchange, archive existing data, and log equipment run time.

The SCADA system involved networking ten Allen-Bradley PLC-5s to seven Pentium PCs. Intellution software gives plant operators multiple screens of information, from which they can perform all necessary equipment interface, log equipment runs, and produce trending graphs. The system's design required the integration of equipment and software from multiple manufacturers, all selected for their records of reliability. Additionally, redundant instrumentation, alternate control algorithms, and on-line backup systems were installed to help maximize reliability.

For the effluent pump station, adjustable and variable speed pumps dictated the use of level-based algorithms to provide the control of critical measures needed to maintain the plant's balance and effectiveness. Safety was a design concern since reclaimed water from the plant is used to irrigate area golf courses and lawns.

(above) Revere engineer works on the critical task of developing the data base. (below) Effluent pump station.