New plant, SCADA system mean better remote control for Canadian water treatment plant
- Canadian city needs accurate, real-time data gathering in SCADA system.
- New remote stations manage water distribution system from source to city limits.
- Alarm system, return on investment do not disappoint plant personnel, managers.
By Ellen Fussell Policastro
The City of Thunder Bay is a growing community on the shores of Lake Superior in Ontario, Canada. Ranked as one of the top 10 cities for business in Canada, population is likely to continue to increase from the 120,000 citizens who live there today. To provide safe drinking water as well as protect the environment, Thunder Bay set a goal to implement lake-to-lake water management-taking water from Lake Superior through the treatment process to the distribution system, and then back through the pollution control plant before returning it to the environment. In less than a decade, Thunder Bay has succeeded.
The old electronics system used to be connected by a telephone line and involved local computers to transmit the information. "Moving to PLCs at each of the water stations tied all these systems together for easier decision making," said Carl Goodwin, process engineer at Thunder Bay. After expanding again in 2004, the plant is now updating its system for more effective process management by having the same software at all of their remote locations, "which cuts control costs and provides standardization at all locations," Goodwin said.
"The remote stations manage the water distribution system from source water treatment plant to the city limits," said John Marchant, electrical engineering technologist from AutomationNow, system integrator for the project. "These stations include booster pumping, water storage reservoirs, pressure zone stations and storm lift stations. There are a total of 16 new and existing stations online and two more currently in the construction phase." Integrating these stations into the current SCADA system was easy with the new system, he said.
"We now have greater station control," Goodwin said. "Operators at the central treatment plant can get information more quickly and can relay information back and forth," he said. "They can now remotely control these locations when before they could only gather data-no control process was available before. They have control over chlorine residual and water pressure. We even have a more efficient water model by being able to look at gaining energy efficiencies," he said. "Having this control, we can more fully implement a more efficient water model."
Thunder Bay was actually the first of its kind to achieve lake-to-lake water management by constructing an entirely new facility. While the previous plant used direct filtration with sand filters and disinfectants, the Bare Point Water treatment plant uses an advanced ultra filtration system to purify the city's water, while expanding daily capacity from 14 million gallons to 25 million gallons.
Challenges included integrating an existing pumping station with the new plant equipment as well as planning for future expansions. The initial facility had 12 PLCs, with 20 additional remote pumping stations to come that would incorporate PLCs from different manufacturers. Communications between the local PLCs and remote locations would be vital to the success of the project.
Without the ability to closely monitor and control this complicated system, the quality of Thunder Bay's water would be at risk. So it was critical to find the right supervisory control and data acquisition (SCADA) system-one versatile enough to meet the needs of the new facility plus its future expansion. Bare Point required accurate, real-time data-gathering to ensure reliable control of the plant's equipment, regardless of location. Recording and logging the data, sounding alarms for threshold conditions, and securely storing information were also priorities. The new system needed to be easy to use as well as provide comprehensive reports for management's informed decision-making.
A Windows-based system located in the operations center of the main plant controls the Bare Point plant software. "Redundant servers with UPS backup systems log over 5,000 points of data, 24 hours a day, 7 days a week," said Larry Levchak a manager at AutomationNow.
The human machine interface (HMI) software forms the core of the Bare Point system. In the application design phase, it provided power and flexibility as well as connectivity for the broad range of devices in the local and remote plant locations. Now operators can closely monitor pumps and control valves; graphics let them visualize water moving through the plant.
Working with the new software, the historian provides a high-performance, real-time, and historical database to integrate the operations center with the plant floor. As an extension of Microsoft SQL Server, the historian collects comprehensive Bare Point operating statistics while reducing the volume of data to store. And it integrates this information with event, summary, production, and configuration data.
For desktop-based analysis and reporting, another software package designed into the system allows Bare Point's process engineers to spot specific trends in real time and prepare historical reports, which they can export to Microsoft Excel. Simple point-and-click dialogs mean plant operators can trouble-shoot problems and identify operational inefficiencies more easily.
Alarms allow birds-eye view
Plant operators rely on the new SCADA alarm system to maintain water quality. If an instrument takes a reading that is out of a pre-determined range, an alarm sounds-both on the alarm screen and a plant-wide alarm system.
The new SCADA system allows operators to view all remote stations. The SCADA application runs on two redundant servers. Should there be a failure, the secondary is the failover node to the primary. If communications are lost to the historian, the data continues to store locally, forwarding data when communications re-establish.
The "remote stations" menu helps with navigation, communications monitoring, and alarming for all stations located throughout the city of Thunder Bay. The menu heading will also indicate what screen the operator is currently on, including time, data, and the ability to silence the reactive alarms. The silence horn button will flash red when any unacknowledged active alarm is present. A keyboard button is for the tablet control. When the tablet is in use, it connects via remote desktop so there is a need to access a soft keyboard. The lower alarm template uses the bottom 100 lines of the screen. This alarm window distributes to be common to all workstations for alarm recognition.
"The operator can have a bird's eye view of the city of Thunder Bay with geographical location of all stations," Marchant said. When selecting the "location map" button, the city is displayed into two sections, Thunder Bay North and Thunder Bay South. When an operator clicks on any of the indicated stations, it will jump to that station information screen. "Each of the remote stations has a consistent look and feel to it," he said. On the lower edge of the process screen is a submenu. This allows the operator to view an alarm summary and a station utilities breakout, as well as make setpoint changes, and view trends.
Throughout the process, common popups are available to the operator. Using a popup screen helps control pumps. When clicking on a selected pump, a popup will appear with the required control and information of that pump. The popup will give the option to start or stop the pump. It indicates whether the pump is ready and running. Status displays tell if the pump is in "hand" or PLC mode. When in PLC mode, you can control the pump manually or automatically.
Lower upgrade costs, less development time
With remote stations that attach seamlessly to the existing network, development time is minimal, and "the operators can control and monitor the plant from a single terminal if required," Marchant said. With such a structured programming regime, "it was easy to integrate the remote stations. All other station configuring and programming aside, upgrading the stations only required about two days on average to develop and commission each station."
The training facility also gives instructors project live views of the operations, providing a highly productive environment for learning, group analysis, and troubleshooting. "It's very easy to use," said Michelle Warywoda, a process engineer at Bare Point. "I am able to pull whatever parameters I need into one trend and see how they're related and make better-informed decisions."
"The ease of use is the same for everyone," said Mike Bazdarick, a water treatment supervisor at Bare Point. "That gets everyone on the same page really fast. And that's important when you want to increase efficiency and run your plant the best that you can."
The city of Thunder Bay saves man hours per station, which lowers the cost of the upgrades. "The production of water at the treatment plant is important, but the system is only as good as its distribution," Marchant said. "All corners of the city can now be monitored and any issue corrected quickly and efficiently." As a result, the new water distribution system has led to a reduction in costs and an increase in efficiency from the first day the system was online.
Return on investment came in record time because "real-time reporting enabled more effective regular maintenance for reduced downtime," Marchant said. "And historical trending reports led to greater visibility and increased operational efficiencies." But the integrator expects the biggest return on investment to come as the plant adds future remote stations, which means development time for the additions could be cut in half.
ABOUT THE AUTHOR
Ellen Fussell Policastro is the associate editor of InTech. Her e-mail is firstname.lastname@example.org.
Thunder Bay system profile
The membrane filtration system consists of five trains of ultra filtration membranes. These hollow fiber ultra filtration membrances use gentle suction to filter impurities from water.
Thunder Bay's 125,000 residents get their drinking water from two municipal water treatment plants, Lock Lomond and Bare Point. However, in 2003, after completing a Class Environmental Assessment (Class EA) process, the city's Council decided to retire the Lock Lomond plant and to upgrade and expand the Bare Point facility to provide all the community's drinking water from a single source.
Thunder Bay's drinking water distribution system includes five storage facilities-the Hodder Avenue standpipe, Duke Street reservoir, McIntyre reservoir, Hazelwood reservoir, and the newly constructed Rockcliff reservoir. While some parts of the distribution system date back to 1909, the average age of the pipes is about 50 years old. Water can be moved back and forth between the two distribution systems as needed through the James Street and Vickers pumping stations.
The retirement of the Lock Lomond treatment plant took place in February 2008. The Bare Point plant-originally built in 1903, and expanded in 1970 and again in 2007 to its current capacity of 113.5 million liters per day-will then supply the entire city's drinking water. Bare Point's treatment methods include pre-chlorination, coagulation-flocculation, membrane ultrafiltration, and post-chlorine disinfection. The plant's unique ultrafiltration system represents state-of-the-art technology.