Globally, the water/wastewater industry is evolving. Delivering reliable, safe and affordable access to water is no longer solely on the minds of water and wastewater managers. Raised consumer awareness and stakeholder operational demands over this most precious resource are guiding utilities to build smarter, more sustainable infrastructures.
Rockwell Automation has many successful solutions and shared examples during the Water/Wastewater Industry Forum at Automation Fair this week in Philadelphia. Several water professionals discussed industry trends and requirements. They also provided examples of how advancements in technology help utilities to design, operate and maintain smart water plants.
"This year water/wastewater is one of the industries highlighted in The Connected Enterprise industry pavilion," said Kevin Hurdle, water/wastewater industry manager at Rockwell Automation. "When we talk about The Connected Enterprise for the water/wastewater industry, the key is to gather the information and present it to the enterprise system from instruments, smart equipment and skids to smart clients. It is just like other industries, the data is captured, contextualized and used to create actionable results."
The connected water plant is something Rockwell Automation is helping end user customers, OEMs and partners realize. The first presenters discussed a recent project at the City of Tacoma where the control system for its wastewater treatment system was replaced with a Rockwell Automation PlantPAx distributed control system.
TSI Controls in Lynnwood, Washington, was the integrator and general contractor for this $12 million project. This Rockwell Automation Solution Partner, with more than 50 employees, has been in business for approximately 48 years and is PlantPAx DCS-certified.
The City of Tacoma, with approximately 208,000 residents, operates two wastewater treatment plants, including 48 lift stations and about 650 miles of piping. The majority of the wastewater (80%) is residential, and 20% is commercial.
The central treatment plant was built in 1954 and has a capacity of 139 million gallons/day (MGD). It had major upgrades in 1988 when secondary treatment was added and in 2006 when capacity was added. The northern treatment plant was built in 1968 and handles 30 MGD today.
"We were faced with the decision to either upgrade our existing DCS to a newer version or replace it with something else," said Chris Roberts, electrical/instrument technician, City of Tacoma. "We used outside engineering services to consult on the technology selection. In these two plants, the operations staff was the group responsible for the DCS programming and had a lot of ownership in the existing system. They were very reluctant to use anything different."
Eventually, we did some project cost estimates and interviewed and visited other wastewater sites near us with similar distributed control systems, as well as other successful PLC-based systems, continued Roberts. "All in all, we found that Rockwell provided much better support than the current provider—better local support and phone support," he said. "Both systems could do it; that was never an issue. However, with parts being available blocks away from our office and at a better price point, it was an obvious decision to go with Rockwell for this upgrade."
Contractor selection was not based on low bid. "We scored the contractors we interviewed, with 25% based on background, qualification and experience; 50% was weighted on project understanding, delivery and approach," said Roberts. "It was important that the supplier have skills, ability, personnel and methods to lead us to a successful project completion. Sustainability was weighted 5%, and only 20% of the project selection was related to price. In the end, TSI Controls was selected and they were the lowest bid."
A collaborative solution
"The goal was to change this system from what I called 'manualmatic,’" said Roberts. "We had a DCS with all these capabilities, but the operators would actually turn off all the features and hard-set the setpoints. They were very proud that they could make it work that way. We wanted all the operators to be on the same page doing the same things and use setpoint control."
Key to the success of this project was the collaboration between TSI Controls and the City of Tacoma. "We formed a support team with two operators, two instrumentation-and-electrical (I&E) technicians and a systems engineer," said Roberts. "We wanted a collaborative approach from the start. The support team worked closely with TSI to test the hardware, verify the field loops and perform factory acceptance testing (FAT) and control narrative tests. The team was also tasked with unexpected repairs. With the many upgrades, we found many existing instruments and equipment not working; much needed to be fixed on the fly."
A big part of the upgrade was the use of the PlantPAx DCS, and there were many benefits, said Lucas Koelle, project engineer at TSI Controls. "Rockwell's integrated hardware and software package just makes it easier to get a project to a successful completion," he said. "The detailed process library was very useful in this scenario. It provided a standard method of operation for all the users. It helped the team understand how to use the system while breaking away from the original DCS."
As a systems integrator, Koelle added, the extensive use of add-on instructions helped reduce programming time and get things done quickly. "Rockwell did a lot of the leg work, and we could just take the end result and use it," said Koelle. "It also helped to simplify the integration of the many non-Rockwell devices into PlantPAx objects for use in the new control system.”
As part of the project, TSI provided two industrial data centers that consisted of FactoryTalk View Site Edition, FactoryTalk VantagePoint, FactoryTalk EnergyMetrix, FactoryTalk AssetCentre, FactoryTalk Historian and ACP ThinManager.
The PlantPAx DCS in the two plants consisted of 22 PLC control panels with ControlLogix L73 processors, 35 remote I/O panels, 23 vendor panels converted over to the PlantPAx standard, six quad-screen workstations and 49 thin clients.
"Originally, we conceptualized using high-performance HMI as the industry is heading that direction,” said Roberts. "However, when we started rolling it out to the operation staff, there was a large resistance. They were used to the older graphics, black background, lots of animation and colors, so we made some changes. One of the many useful features in PlantPAx is the flexibility to adjust it to scenarios like this. Of course, we couldn't just force the high-performance HMI standard on operations. We created a modified version of the standard faceplates adding in some color and more of the extensive details the operators were looking for. We did eliminate much of the animation but worked to maintain the screen color structure that the team was used to."
Challenging and successful
"There were many challenges," said Koelle. "One was cutting over the system while keeping the plant operational. It's not easy to stop wastewater, so we needed to do whatever it took to keep the pumps running."
Transitioning to setpoint controls was difficult as well. "The entire culture of operations and how they ran the plant had to change," said Roberts. "Setpoints were new for them. There were many questions on, 'Why does it do this?' so we spent a lot of time reviewing the control strategies. Over time, operations started working through the strategies themselves."
The project was completed successfully, and one of the biggest successes was that it stayed within budget. "We had contingency money available to do the things we wanted and the PlantPAx system was flexible enough to do them,” said Roberts. “However, the working relationship between the City of Tacoma and TSI Controls was the real winner here—the relationship, the trust we built. We weren't going to do anything to TSI that would hurt their business, and they were going to be flexible and help us with our schedule and requests. That was a big one for the city."