Innovative UV system reduces plant’s energy use and maintenance

After a 17-year run, the UV disinfection system at the French Creek Wastewater Treatment Plant was limping toward the finish line. The plant decided to replace the system with Xylem’s Wedeco Duron UV solution that requires dramatically less energy and maintenance.

The French Creek Wastewater Treatment Plant is wholly owned and operated by the city of North Ridgeville, located in northeast Ohio. The plant services about 12,500 accounts through nearly 300 miles of pipeline, which ultimately returns the treated effluent to French Creek.

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While the plant is only a few decades old, North Ridgeville has continually upgraded and maintained its operations. The city has invested millions of dollars to ensure that the plant remains current with technology and in compliance with changing environmental guidelines.

Challenge: replacing an outdated UV system

Although the plant is ready to serve its growing customer base well into the future with safe, sanitary, and cost-effective treatment of sewage, it was dealing with a dilapidated UV disinfection system installed in 2000. The equipment was also labor intensive.

For example, wiring for the lamps was routed inside the lifting arms. As the wiring aged, it would wear out causing a short. It was difficult to thread the wire through the arm.

Ballast assemblies were located above the channel and were cooled by a glycol loop. Loop tubing leaked, which made the ballast area slippery. The city was also finding it challenging to locate replacement parts, as the manufacturer was slowly rendering the equipment obsolete. Finally, the UV system was consuming a large amount of power as it inched closer to the end of its life.

The city needed to find a replacement UV system that fit into the same footprint, offered lower power consumption, and required less maintenance work.

Selecting an energy-efficient, compact UV system

Working closely with the city’s consulting engineer, Jones & Henry Engineers, Ltd., North Ridgeville selected the Wedeco Duron UV system over other inclined UV systems. The decision was based on a 20-year life cycle cost analysis of the system, its energy efficiency and its ease of maintenance.

The Duron is a 45-degree, inclined, open-channel UV system that has an integrated, compact, automatic-lifting device. It also features energy-efficient, high-power Ecoray lamps. It was the perfect answer to the French Creek Wastewater Treatment Plant’s requirements.

According to the client, the removal of the old system was fairly straightforward. The client was able to use the existing channel as the Duron UV banks are actually narrower than the space previously used. The area where the old UV system was located was demolished and a new level control gate structure was constructed.

OptiDose control automatically adjusts energy consumption

The Duron UV system is designed to treat 22 million gallons per day (MGD) and can be upgraded to a future peak design flow of 32 MGD by adding an additional UV bank. Wedeco’s UV system not only results in lower capital cost, but lower energy consumption as well.

OptiDose, a sensor-based, real-time dose control, monitors operating conditions including flow, UV transmittance (UVT), and UV intensity. With proven control logic, OptiDose adjusts the energy consumption to the minimum needed to meet dosing requirements.

Easy maintenance and cleaning of the UV system

Central to the design is how easily and efficiently the system is maintained and serviced. Lamps can be easily replaced while the modules remain in the channel. Safe and ergonomic maintenance is ensured by dry-top UV lamp access and a compact, integrated lifting mechanism.
Cleaning is also simple and safe thanks to the Duron’s automatic, chemical-free Opti Wipe system. Wipers consist of unique polytetrafluoroethylene and fluoroelastomer rings, which are effective even in waters with high fouling potential.

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