Western Lake Superior Sanitary District Extends Asset Life with Collections System Monitoring 

About 14 billion gallons of municipal and industrial sewage flow annually to the regional wastewater treatment plant through a 75-mile sewer network. Treated water is then discharged to Lake Superior, and ultimately, the Atlantic Ocean.

Preventing sewer overflows and leaks into the watershed is a top priority for the utility. Pump stations and force mains serve as an effective way to control sewer overflow.

As force mains (also termed rising mains) are not accessible for inspection by camera, they can be notoriously difficult to evaluate. To help develop their asset management plan, WLSSD hired a consultant to evaluate their force mains and identify vulnerabilities in the network.

Asset Management and Risk Assessment

The consultant conducted measurements and modeling on three force mains to identify the locations with the greatest risk of failure, which could lead to costly interruptions of service; and recommended improvements to reduce that risk. Based on this analysis, recommendations were provided based on worst-case scenarios, ranging in cost from $185,000 to $1 million in capital improvements.

Faced with this significant investment, WLSSD decided to obtain additional data to verify the model results before committing to the spending.

PIPEMINDER-ONE technology from Badger Meter was selected, providing pressure transient detection, burst alarming, and intelligent asset performance analysis to alert scenarios such as high/low delivery pressures, blocked pipes, trapped air and failing pumps or valves.

Data is sent to the cloud-based RADAR Pressure Management Data Platform, where it is analyzed against pre-set network performance parameters. This reveals the system’s operating state, enabling operators to quickly pinpoint issues with readings that fall outside of the norm.

Data Analysis and Findings

Analyzing multiple locations, WLSSD found that the data generated during normal operations lined up reasonably well with the models, as expected.

PIPEMINDER-ONE enabled the WLSSD team to verify or identify specific problem areas within their rising mains. The modeled data also identified a stuck air release valve that was providing limited air transfer to and from the pipe. PIPEMINDER-ONE allowed WLSSD to confirm that this component was not critical to force main operations, and the risk of an emergency repair from this connection was eliminated without detriment to the operation of the system.

Stuck Air Release Valve

At one lift/pump station, WLSSD had planned to vent an air release valve manhole to improve operating conditions. PIPEMINDER-ONE data later revealed that this change would not benefit pressures at the station or in the pipeline. This finding surprised the WLSSD team, and they changed their approach. Additional work was planned to evaluate whether reinstating a former air release valve location would improve pressures.

Transient Events Due to Power Failure

The pressure data also helped capture four separate transient events that occurred when pumps shut down due to power failure. The location of the transients was documented and showed significant additional pressure on the pipes that could cause a failure if the operation continued.

The Badger Meter team worked with WLSSD to highlight the importance of determining the cause of the outages to respond effectively and mitigate the problem.

Informed Decision-making

WLSSD improved its ability to make decisions regarding capital investments and operations backed by accurate data. This data provided the information necessary to invest resources where there was both the greatest risk and greatest potential benefits.

“When we compared the PIPEMINDER-ONE data to the modeling data [from previous efforts] it aligned well in routine conditions, however, when more significant events occurred we realized behavior was actually different than predicted, with increases in pressure where we would have expected decreases,” said Dianne Mathews, P.E. Senior Engineer, Western Lake Superior Sanitary District. “The data helped us to actively spot problems we would not have been unaware of.”

Improved System Availability

Industrial and residential customers rely on WLSSD’s systems 24 hours a day, seven days a week. Shutting down a pipeline due to transient events or component failures is not an option. By proactively identifying potential problem areas using pressure data generated by PIPEMINDER-ONE, WLSSD could take steps to reduce the risk of operational interruptions.