Click here to enlarge imageFor central processing and remote terminal unit control, Pigeon Forge selected Allen-Bradley ControlLogix® and MicroLogix™ controllers. Installing controls at each blending basin allows plant workers to choose which pump to turn on and gives them the ability to adjust the blending speed as needed. A combination of drives and motor starters located inside networked intelligent MCCs regulate pump and blending speed.
Throughout the facility, Rockwell Software RSView®32™ HMI software with RSView Active Display™ System allows operators to monitor all aspects of the process. Operators can view basin levels, filter operations, chemical application, flow rates, water turbidity and chlorine content. Plant workers can run many operations remotely through the RSView Active Display System, including controlling the remote water pumps at Douglas Lake, based on the basin levels at the plant.
As capacity increases, remote monitoring and control eliminated the need for extra personnel at Pigeon Forge. For example, filter operations at the basin, including scraping floc from basins into the trough and transferring it to the wastewater plant, can now be monitored on site at the filter station via four Allen-Bradley PanelView™ HMIs or remotely via RSView. Personnel can even remotely add the flash mix.
"RSView clearly displays the entire treatment process," said Joel Skelley, electrical engineer, SSR. "RSView libraries and pre-built parts help us create intuitive screens that follow the flow of the system. This allows plant personnel to move smoothly from one screen to the next and see water flow rates for more efficient system monitoring and control."
With RSView continuously presenting data, record keeping has become much easier. Data files are sent directly to the plant's server, where they are archived for a year. After the year has passed, the data files are then saved to CDs and stored offline. The stored data can be used for faster troubleshooting and maintenance. When an alert flashes on the screen, plant engineers can quickly reference the stored data to determine when the problem started and how it should be resolved. As EPA data collection requirements evolve, the water plant will be able to comply by modifying its collection parameters.
Saving valuable construction time is always a high priority for any municipal project. Rockwell Automation engineers assembled and factory-tested the Motor Control Center before shipping it to the site - a step that reduced installation time by 10 percent. The factory production assembly and test made on-site wiring and start-up much easier and eliminated many of the common factory-to-field installation problems typically associated with this type of installation. Overall, the time to engineer the system was reduced by 15 percent, and the installation and startup time was reduced by 25 percent. SSR's engineering liability was reduced by 20 percent, creating more engineering time to focus on process improvements. Once the system was installed, SSR provided start-up and on-site operator training.
"Training on the new system was easy," said Lynn Light, chief water plant operator, Pigeon Forge. "The graphics walk our personnel through the process, improving comprehension and reducing training time."
In addition to the controls at the Douglas Lake pump house, the city also integrated a contact-switch-based security system to alert the district of unauthorized entry. By integrating the intrusion detection system into the remote SCADA system, the district is better prepared to minimize site security vulnerability at these remote sites.
If the city of Pigeon Forge had expanded its production capacity using the same systems, it would have needed more than double the personnel it was using at the time. With the automated system in place, the City of Pigeon Forge Water Plant has successfully tripled its capacity to 12 mgd, without adding plant personnel - saving an estimated $200,000 per year. With higher capacity, the city now meets projected city water demands, which continue to grow 10 percent annually. The added production capabilities also generate revenue for the city. Able to triple its capacity, Pigeon Forge can sell water to neighboring towns.