The treatment of water for residential and industrial use dates back thousands of years. From the Egyptians purifying drinking water through coagulation techniques to the Romans constructing aqueducts – water treatment has been a cornerstone to our civilization.
Some of those same antiquated techniques, such as coagulation and filtration, still exist today. But unlike ancient aqueduct bridges and sand, modern methods require technology to instantly serve thousands of residents and businesses – anytime, anywhere.
The Commerce Township Wastewater Treatment Plant, located in Commerce Township, Michigan, is one of many treatment facilities taking advantage of automation equipment to treat more than 2 million gallons of wastewater per day from its community.
A Bump in the Road
In 2010, the Commerce Township WWTP underwent a significant expansion project to meet the anticipated growth of the surrounding communities by nearly tripling its capacity from 2.4 million to 8.5 million gallons per day. After the installation of variable frequency drives (VFD’S), the Commerce Township WWTP hit a few bumps in the road.
“We were having numerous power interruptions that required our staff to reset process equipment,” said Brian Bennett, operations engineer at Oakland County Water Resources Commissioner’s Office (WRC) in Commerce Township. “Over time, the interruptions were causing damage to our equipment. This equipment doesn’t fail immediately – it’s similar to hitting speed bumps in your car. You can go down the road and hit potholes only so long, but eventually it’s going to take its toll.”
After several months, the power interruptions resulted in multiple hours of unplanned downtime that required Commerce Township WWTP staff to manually reset equipment with limited insight as to the cause. After the interruptions resulted in two damaged variable frequency drives (VFDs), Commerce Township WWTP knew it needed to get to the bottom of the problem.
A Treatment to the Interruption
To help identify the root cause, the Rockwell Automation Global Solutions team, who earlier installed the VFDs, ran multiple equipment tests to the installed VFDs. The goal was to see if the problem was being caused by faulty equipment or by the quality of the incoming power. According to Steve Liebrecht, water and wastewater industry team lead for Rockwell Automation, since power utilities typically measure availability – not quality – it is common for these small occurrences to go undetected.
The team decided to implement the Allen-Bradley® Bulletin 1608™ i-Sense® voltage monitor to collect, analyze and notify subscribers of incoming power quality. The monitor can interface with the Internet of Things in several ways with an analog phone line, or connect to the existing IT infrastructor with a IP address. Yet, in some highly secure environments, choosing to not connect to the local IT environment may be a preferred approach. Once the data is collected, it is hosted in a web portal for customer use and is also integrated with other i-Sense monitors in the area to better understand regional power disturbances.
“The installation of the i-Sense voltage monitor allowed us to focus on specific periods of internal data and identify where the main problems were occurring,” Bennett said. “As a result, we were able to pinpoint the issues as they related to our incoming power.”
Once the voltage monitoring solution was installed, the WRC also moved forward with a power quality study to better identify and document issues throughout the plant. The results allowed the Rockwell Automation team to confirm that voltage disturbances took place the same time the VFDs were tripped on overvoltage when running.
The monitor also alerted the facility about their generator power events. Fast generator shutdown and restart practices can impact the long-term durability of the drives. Controlled power cycling of VFDs should be managed in a methodical manner. For that reason, the Commerce Township WWTP was advised of practices that were shortening the life cycles of its VFDs.
It Made Sense
Within months of monitoring incoming power, Commerce Township was finally able to determine the root cause of its failed VFDs.
“There were two reasons why we installed the i-Sense voltage monitor,” said Greg Knauf, superintendent of the Commerce Township WWTP. “One reason was due to our consistent power interruptions and the other was a result of the two damaged VFDs. The data provided us documentation to go back to our power provider with results and work with them on addressing the power quality issues.”
While the Commerce Township WWTP now has data to work with its power provider on quality interruptions, the plant has also gained a sense of reliability since its implementation. Just a month after the product was installed, Knauf received an email from the monitor that indicated the WWTP experienced a power event. The WWTP’s SCADA system did not send out notification to Safety Dispatch due to the SCADA system being down.
“The moment I arrived home, I checked my laptop due to my concern of the WWTP’s equipment. Sure enough, 95 percent of the WWTP’s equipment was tripped,” Knauf said
As a result, Knauf was able to call an operator to restart equipment and get the plant up and running. If the power event would have gone unnoticed, this could have greatly impacted the operation of the WWTP and compliance could have been affected.
Since the voltage monitoring system and power quality study, the Commerce Township WWTP has been able to detect solutions to help buffer incoming power events. During the evaluation phase for instance, Rockwell Automation determined that while one transient surge suppressor was installed, multiple suppressors should be installed. This helps safeguard operations because interruptions are based on a variety of factors, including where and when the event takes place.
“One of the things that was enlightening to me was having clean power is not always the case,” Bennett said. “In fact, it might be to the point where it can damage electrical equipment. It doesn’t mean that fluctuations will damage everything, but it was eye-opening that fluctuations happen on a regular basis.”
Now, Commerce Township uses its voltage monitoring system to troubleshoot power events with its provider, while also mitigating its operation against future occurrences.
“The i-Sense voltage monitor has empowered management with data beyond what’s provided with the existing SCADA system,” said AJ Lee, sales engineer at McNaughton McKay “We’re hoping to continue the installation throughout other locations in the county so they are able to receive usable, actionable information.”
