A Booming Population
In 2011, a major urban area in the United States was experiencing a rapidly growing population due to its hip vibe and low unemployment rates. The city was feeling the growing pains and decided to build a new greenfield water treatment facility. Without it, the city risked reaching capacity.
Based on their experiences operating at other facilities, the municipality’s staff wanted the new facility to have all the process control advancements available.
Confounded by Nuisance Alarms
Alarms had been posing serious issues at the district’s other treatment plants. Operators could not distinguish between nuisance and serious alarms, so they were ignoring all of them. And the color display on the human-machine interfaces (HMIs) made it difficult for operators to identify and act on priority information.
The facility managers wanted an alarm system that would alert operators to issues that required immediate attention using a gray-scale HMI that they could read clearly at a glance. They also wanted to track the time it took operators to respond to alerts.
In addition, the facility’s staff needed to log five years’ worth of operating data to comply with federal regulations. They wanted a system with a historian software application that could easily integrate with their control system data and with the district’s existing OSIsoft PI System.
Implementing a Modern System
To best meet the federal standards, the company decided to base the alarming on the ISA 18.2 alarm management standard. For the system design, they brought in the design and engineering firm CH2M Hill, a Recognized System Integrator and member of the Rockwell Automation PartnerNetwork program. They chose Rockwell Automation to supply the technologies and support because the district had used the company’s solutions at other plants.
“We’ve implemented the PlantPAx modern DCS system from Rockwell Automation at other customer facilities, and recommended it to the wastewater treatment company for their new site,” said John Costello, west regional technology lead for automation, CH2M Hill. “Also, our partnership with Rockwell Automation helps provide an ecosystem of support for any maintenance issues.”
To lay the foundation for the PlantPAx system, CH2M Hill designed a virtualized control system using a high-availability, redundant, storage-area network (SAN). Six virtualized servers ease and speed redundancy, allowing staff to start operations with a backup server in case the primary server fails, reducing the risk of water-treatment interruption. The network can be accessed and managed from a state-of-the-art video wall in the plant control room.
At the operations level, CH2M Hill designed in the PlantPAx solution for process control. The solution integrates all operations – process, discrete and motor control – into one system to increase productivity of operations across the mile-long facility. Realizing the district already had too few experienced operators, CH2M Hill designed an intuitive control system that required less training to operate.
CH2M Hill leveraged alarms within the PlantPAx system, which monitors over 60,000 tags and 6,000 alarms. It tracks which alarms go off most frequently, improving predictive maintenance and reducing the risk of bigger issues. The design firm also developed HMI graphics with a modified gray scale to further support the alarm standard and ease operator use. Different types of alarms are set based on the level of priority. Staff will be compensated for responding to high-priority alarms quickly.
Historian software in the PlantPAx modern DCS system gathers on water conditions historical data on temperature, pH levels and other data points for five years. This information-keeping meets federal regulations and helps operators create a baseline to better identify aberrations in processes. The historian software also connects to an existing PI data repository for better data collection. In case of connection issues, the new greenfield facility will continue to gather data and update the repository when reconnected.
The system is built using IP-based network communications standards to help streamline control and information flow, and enable real-time diagnostics and electronic documentation. An EtherNet/IP network enables remote access and maintenance through secure remote connections. Operators can access and control key processes from anywhere on-site using tablets. Ten controllers based on the Logix-based control platform communicate via EtherNet/IP. Directory software helps centralize access to resources and components – such as displays and tags – in the control system. Operators can easily find data on any part of an application.
In addition, the CH2M Hill team used FactoryTalk AssetCentre change management software from Rockwell Automation to integrate the plant’s instrumentation from Endress+Hauser (E+H), a Rockwell Automation Strategic Alliance Partner. The instrumentation gathers process data to predict chemical usage, as well as better monitor water conditions, and the composition and level of incoming effluent. The asset-management software provides process device configuration and automatic program version control, helping operators quickly set parameters for 1,800 devices. They can also configure and troubleshoot the devices, as well as schedule, manage, track and report on device activity.
Approaching the Finish Line
Once implemented, the alarm system and gray-scale HMI will meet the ISA 18.2 alarm-management standard, and will limit the alarms per hour to help improve operator awareness. The greenfield facility will meet federal regulations with five years of data on hand. The historian software will eventually be connected to and synced with existing facilities.
The intuitive PlantPAx system provides multidiscipline control capabilities, and the standardization on the PlantPAx system and E+H instrumentation will allow facility operators to simplify inventory, and speed training and integration time. Facility operators will be able to manage the water treatment process from the control room or wireless tablets instead of sending people into the field – thus improving productivity and personnel safety.
Asset-management software within the PlantPAx system helped configure the E+H instrumentation, reducing configuration and commissioning time by 40 percent. The software will also securely file device data for record-keeping and trend-tracking.
Design of the facility is complete, and CH2M Hill team used its Replica process-simulation software to successfully simulate the system.
