Cobb County, Ga., adds automation to improve wastewater treatment operations.
Cobb is one of metropolitan Atlanta's most populated counties. Nearly one million people call it home. Millions more work, play and visit inside the borders of this suburban stretch of neighborhoods, businesses and parks. The infrastructure is among the area's best and getting better. The Cobb County Water System (CCWS) is a strong case in point.
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The CCWS is capable of handling three to five times more than the combined 80 million gallons of sewage and runoff it processed daily through four regional treatment plants. The aging SCADA systemthat monitored and managed the facilities, however, was due for a major upgrade, as the county was experiencing the costs that come with lost productivity and inefficiencies.
The Challenges
The biggest challenge facing technicians charged with upgrading the operation was identifying and implementing a solution that could seamlessly unify the CCWS. The four primary plants and 42 pump stations, which direct wastewater from neighborhoods and developments throughout the 345-square-mile county, had been deployed over time by an assortment of integrators.
“Our old architecture was disjointed and aging,” explains Pat Brechbill, technology support manager for the CCWS who heads up a team of seven process control analysts and six instrumentation technicians. “So, we focused on implementing a future-proof plant upgrade capable of providing our staff with a clear view into the whole wastewater treatment system. The main goal is to give our engineers, maintenance teams and operators real-time, anytime plant access from virtually anywhere.”
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| Plant overview screen shot |
Plant unification was the top priority, but other lofty objectives loomed. The elimination of cumbersome and complicated license management procedures was high on the punch list. Time-consuming programming and troubleshooting requirements had to go too, along with outdated graphics and screens.
The Solution
The Technology Support Group (TSG) considered a new release of the plant's 12-year-old SCADA software. But after months of research and brainstorming all the available options, the team instead initiated a full blown replacement to leverage the full potential of the existing programmable logic controller (PLC) platform that was in service across much of the CCWS operation.
With a PLC platform already in place throughout the system, the TSG opted to standardize the upgrade on the series of PLCs. “The synchronization of our PLC and SCADA software platforms was critical. We had to implement a system we knew would grow and expand together,” says Brechbill, who ultimately decided to replace the old SCADA with a web-based WinCC solution.
The Plant's Full Potential
“The S7 series is an extremely powerful PLC platform, fully capable of communicating with different network layers simultaneously. Most integration software can't do that,” Brechbill says. “By marrying the Siemens PLC with the WinCC SCADA, we can get the most from our architecture and our plant far into the future.”
Once the system-wide upgrade is complete in late 2012, all the plants and pump stations will be operating on WinCC and accessible through online portals using Web Navigator. “We want to ensure that everyone who's authorized to operate and maintain the facilities can easily and quickly get as much information and feedback from the plant as possible, but in a safe, secure and authorized manner” says Brechbill. “WinCC and Web Navigator put the whole system at their fingertips. That plant-wide view just wasn't possible before with our limited SCADA.”
Using built-in plant viewing stations or laptops at home or on the road, operators, maintenance and engineering crews can see the entire CCWS or drill down to the device level in any facility to monitor, program or troubleshoot. Web Navigator can be used for web access to anything in the human-machine interface (HMI).
“Before, we had to use a dedicated desktop unit and a limited license pool to manually access the plant,” Brechbill explains. “Our new Web-based SCADA enables portable licensing that allows us to log on at the plant or anywhere, use an online license to see the plant, make the changes and log off. That is a powerful solution that is saving us money and time and opens the door to tremendous capabilities we didn't have before.
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| The Noonday Creek facility was the first plant to be upgraded. |
Prior to the upgrade, when a maintenance technician signed on for a license to check a particular plant, the operator had to be hands off during the troubleshoot effort. That often meant operators went an hour or more without a view into the plant while they waited for the manual license to return to the pool.
The new plant architecture was planned from the outset of the project. “We sat down with Siemens and some of their solutions consultants to make sure we set a sound foundation for the long haul,” says Brechbill.
The WinCC SCADA platform unleashes the full potential of the CCWS. Operators, engineers and maintenance teams at the Noonday Creek plant are already reaping the benefits of automated maintenance and management tools.
Changing a pop up screen in the old system, for example, required the programmer to make the change to every pop up. “Now our pop ups are global, so we make the change to one pop up and every identical screen is updated automatically,” Brechbill explained. “That's a huge time and cost savings. What used to take four hours or more is done in five minutes.”
“Because plants like CCWS feature objects and processes that require redundant programming and setup, Siemens and iQuest (a solutions integrator) have helped us globalize everything we can possibly globalize,” says Brechbill. “The biggest benefit is far more productive plant maintenance and management,” he added.
WinCC enables integrators to automate configuration.
Building on Success
The first plant upgrade at the Noonday Creek facility in Kennesaw, Ga., creating a model for the technology refresh at Cobb's three other treatment plants. Because the system standardized to the PLC and WinCC SCADA, CCWS can reuse all the screens and templates created for the Noonday plant in upgrades at the other system facilities. The South Cobb plant in the Austell community is nearing completion, the Northwest treatment site in the town of Acworth is on deck and the Sutton plant in Smyrna will be revamped by December 2012. None of the plants will need to be shut down during the upgrade.
“The S7 PLC series design allows us to implement WinCC in parallel with our old SCADA system,” explains Brechbill. “As a result, we could beta test WinCC while running the old SCADA at Noonday. Once testing is completed at each plant, the migration to WinCC will be seamless and simple.”
The CCWS hit a wall with its aging SCADA system and couldn't build on the investment made years ago. “Now we're posi-tioning ourselves to take advantage of Siemens' TIA (Totally Integrated Automation) platform. That will enable our operations staff to easily integrate and leverage new technologies and applications in the future,” says Brechbill, who envisions plant access on smart phone and handheld devices fast approaching. “The more portable and flexible the access, the more our teams will know what's going on across the plant,” he notes.
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| The Noonday Creek plant feeds clean, treated water into Noonday Creek. |
One of the mission-critical strengths of the PLC is its networking capabilities and design to communicate simultaneously with multiple servers. While other software packages, including CCWS's old SCADA system, rely on a fail-over platform with a primary server, the upgraded PLC and SCADA platform delivers the same data at the same time to every server.
“Network glitches used to cost our maintenance crews a lot of time because they would have to remote in and manually publish data to the servers. We don't have to do that anymore,” says Brechbill.
The TSG is rebuilding the networking infrastructure of the CCWS in part based on the innovative work done at Orlando's Iron Bridge wastewater treatment plant. Brechbill and his core team toured the facility that underwent its own system-wide upgrade built on the WinCC and PLC platforms.
Self-Sufficient Solution
When Brechbill first joined the CCWS as a programmer five years ago, he was new to upgraded PLCs. “I quickly realized how powerful the Siemens PLC platform truly is and how it enables you to innovate on the architecture side,” Brechbill says.
Now that the Noonday Creek plant upgrade is complete and the learning curve is a thing of the past, operators and support teams “are more confident than ever in their plant management capabilities,” says Brechbill. “Now that we've got the exposure of two upgrades under our belt and a real comfort level with the intuitive SCADA software, our plan is to be self sufficient with the next two plant upgrades and ongoing management,” he noted.
Should CCWS hit any hurdles, it has support in place that has the expertise to help. CCWS now has a standardized, revamped and efficient wastewater treatment system that the staff can easily manage and maintain. The self sufficiency could lead to an estimated triple-digit savings at the Northwest plant alone.
“There's a huge cost savings that comes with self sufficiency in engineering and plant set up,” Brechbill says. “The intuitive nature of WinCC allows us to do much of the work ourselves, to the tune of at least $150,000 in just engineering cost savings at the Northwest facility,” he projects.
Putting a price, however, on what Brechbill considers one of the biggest benefits of the upgrade—a new level of confidence in the operation and the clean water it's putting back into the area's rivers and streams—is difficult. “We've always produced reusable water at our plants, but our system upgrade will no doubt enable us to further enhance our processes and the quality of water destined for the Chattahoochee River, Noonday Creek and other waterways,” explains Brechbill.