The city of Rossville, Ind., owns and operates a 350,000-gallon-per-day wastewater treatment plant responsible for the treatment of wastewater from homes and businesses. The facility eliminates contaminants such as human waste, oil, soap, and chemicals before circulating the water back into the environment. Production time, or “uptime,” is critical for wastewater treatment plants, as they are responsible for ensuring that rivers, lakes and oceans remain clean and safe to enjoy.
Challenge
Rossville was experiencing repetitive equipment failures, primarily in the control devices that monitor flow and tank levels; these setbacks led to increased downtime for the facility. Input failures often result in irreparable damage to larger automated controls systems, leading to significant equipment damage, labor costs and downtime.
Most failures were reported during or shortly after electrical storm activity, indicating that the problems stemmed from poor surge protection within the facility. Without proper surge protection, wastewater treatment plants are prone to higher risk of lightning damage due to their large, exposed surface areas and isolated locations.
Lightning can have a major impact on all electrical equipment found in water treatment facilities. Overvoltage from lightning activity directly impacts instrumentation, communications and sensitive electronic equipment such as gauges, meters and programmable logic controllers. The impact can range from complete failure to data disruption, causing downtime for the facility. Therefore, protection against electrical surge activity is critical and should include a comprehensive approach across all types of facility structures including pump stations, treatment plants, storage, transport, and distribution.
Solution
To solve its surge problem and resulting downtime, the city of Rossville chose Eaton for its expertise in surge phenomena employing the latest design and products.
An Eaton team of Power Quality Experts carefully reviewed the Rossville system and conducted several power quality studies to examine surge voltages, sags, harmonics, and needed support.
Following the facility assessment, Eaton worked with Rossville to design a high-quality solution that would address electrical surge activity across all aspects of the plant. Impressed with Eaton’s expert analysis, broad range of products and knowledgeable field staff, the city began to implement a surge protection system that would provide value and reliable performance for years to come.
Considering the complexity of the system and critical nature of its operations, Eaton implemented a cascaded approach to maximize protection. For main incoming service lines, an Eaton 250 kA, SPD Series surge unit was applied to mitigate catastrophic surge activity coming from external sources such as lightning. At secondary locations, Eaton 120 kA, CVL Series units were employed to further reduce external surge activity and mitigate any internally generated surge activity. Where highly sensitive components were located, the Eaton Aegis Critical Load Filters were used to ensure long-term protection of highly critical components.
Results
Since implementing the Eaton surge protection solution, there have been several lightning strikes and system events in the Rossville area - with little if any electrical damage to the wastewater treatment plant.
According to Utility Manager Chad Colby, “The City of Rossville Utilities (CRU) was continually battling outages and damage from surges, [and] Eaton helped identify a cost-effective and efficient surge protection solution. Based on the amount of downtime and loss of revenue due to equipment failures and damage we experienced earlier, the estimated payback on the entire system is about 1.8 years.”
The investment in a comprehensive surge protection solution seems minor compared to the long-term protection and performance it provides. The city of Rossville was proactive in avoiding potential downtime, which can sometimes lead to untreated discharges and the associated fines. It’s also helping the utility minimize maintenance and labor costs, and ensure accurate electronic equipment performance.
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