When Pima County, Arizona, began planning to upgrade its wastewater facilities’ operations and maintenance programs, it knew the project was a big one—considering that the utility manages 3,400 miles of sewers and treats 82 million gallons of sewage each day across two wastewater treatment plants and three sub-regional treatment facilities. What it may not have realized is how critical high-performance HMI concepts would be to the project.
The principal operational activities of the Pima County wastewater treatment facilities are to manage effluent feeds into the Santa Cruz River and meet environmental quality mandates to reduce nitrogen and ammonia. Key aspects of the utility’s $720 million upgrade of its facilities included increasing treatment capacity, decommissioning an older treatment plant while building a new one, and interconnecting them during the project. The new treatment plant would handle 50 million gallons a day, whereas the older facility handled 37.5 million gallons a day.
On top of these issues, the utility—like most industrial operations—faced a high percentage of retiring workers, as well as difficulty in attracting new workers.
Given the project’s goals, the utility wanted its operators to understand the operational processes better and, therefore, be able to make better decisions and take necessary actions. With these capabilities, the utility would no longer have operators, but multi-skilled operations and maintenance workers.
To achieve this, workers would need a seamless, holistic view into the utility’s processes that could be accessed in the control center as well as in the field.
During a session at the Wonderware 2015 Conference, Brad Callihan, P.E., practice group manager at system integrator EMA Inc., who worked with Pima County on the project, said that the facility was able to achieve its goals by employing situational awareness concepts as part of its upgrade project.
Key to the use of these concepts in the project were the utility’s reliance on ANSI/ISA 18.2-2009 Management of Alarm Systems, High-Performance HMI guidelines, and ASM Consortium’s Effective Console Operator HMI Design. “The only problem was that there were very few water/wastewater industry examples of these concepts being used,” Callihan said, “so there was a lot of resistance to these changes initially. Plus, not all of the technology tools existed yet. So we held lots of workshops to overcome operator resistance.”
A key factor of these workshops involved getting operator input into the new HMI design, even though standards and guidelines would largely direct their development. “The utility’s previous InTouch screens were mostly being ignored,” Callihan said, “because they were in constant alarm flood state. These screens essentially became white noise to the operators. The workshops focused on how to deal with alarms, determine alarm metrics, and implement incremental improvement. Stakeholder input into this process was critical.”
The biggest step in achieving the project’s overarching HMI goals involved moving away from the utility’s use of islands of Wonderware InTouch HMI software and toward Wonderware System Platform.
Operator situational awareness guidelines used to direct the new InTouch HMI development in the system upgrade at the utility focused on:
- Attributes—only show the most critical information and have its representation be intuitive/logical;
- Principles—ensure the new HMI graphic designs are clear and consistent; and
- Characteristics—the HMI should include easy navigation and effectively use color and symbols/graphics.
Following these guidelines, it was decided that “there would be minimal animation in the InTouch HMI screens,” Callihan said. He noted that this was a compromise with High-Performance HMI guidelines which suggest no use of animation. “Making this compromise was important to operator acceptance,” said Callihan, adding that, in keeping with other High-Performance HMI guidelines, there is no use of red or green colors in the new HMIs and that the new graphics clearly show the process state with filled or unfilled graphic backgrounds.
On the new InTouch HMI screens, the most critical elements are the alarms, followed by equipment status and setpoints, then equipment names, loop numbers, and engineering units. “Navigation needed to be easy down to the unit level and from plant to plant across the utility,” said Callihan. “Progressive details—from key performance indicators to unit and sub-unit details and equipment pop-ups—were all about improving context by being logically progressive.”
Benefits of the new HMI system at the utility include:
- 10-30x reduction in process displays required;
- Increased recognition of abnormal process conditions, which means operators no longer have to scroll through displays, with individual alarms aggregated up to equipment/unit;
- 73 percent reduction in average alarm rate, even though the I/O count doubled from 10,000 to 20,000;
- Met regulatory requirements a year ahead of schedule;
- Encountered no serious violations or loss of production while upgrading from InTouch to System Platform; and
- The utility now has the ability to retain best practices and cross-train staff.
