Industrial Utility Efficiency

DO Control System and Turbo Blowers Optimize Energy Use at a WWTF

Every municipality and utility is facing the reality of rising energy costs. In 2010, the Town of Billerica, MA, which is located 22 miles northwest of Boston with a population of just under 40,000 residents, engaged Process Energy Services and Woodard & Curran to conduct an energy evaluation of the Town’s Wastewater Treatment Facility (WWTF) and pump station systems sponsored by National Grid. The objective of the evaluation was to provide an overview of each facility system to determine how electrical energy and natural gas were being used at the facility and to identify and develop potential cost-saving projects.

Conclusions & Recommendations

The energy efficiency project was successful in meeting both process improvement and energy reductions. Furthermore, the environmental benefit of significantly reducing greenhouse gas emissions was achieved. Annual energy savings of \\$39,000 justified the cost of the improvements at the plant. These construction costs will be recouped in less than eight years in part due to the incentives from National Grid.

While a variety of startup issues were encountered, the turbo blowers have continued to run without interruption since the summer of 2012. The Town continues to optimize their control system and at times will “stress” their process systems to further develop their understanding of the treatment processes and how the system will respond. Jeff Kalmes indicates that an upcoming project to identify a replacement or cleaning strategy for the existing ceramic diffusers is currently under discussion. The current challenges would be taking a treatment train offline and emptying the tank for the inspection. Addressing the diffusers will be the final component of a successful project, which will provide an optimized aeration system at the Billerica WWTF while maximizing energy savings.

For more information contact Jack Troidl, P.E., Project Engineer, Woodard & Curran, tel:781-251-0200

The author would like to thank the following contributors to this paper: Lorraine Sander, Superintendent – Wastewater Division, Town of Billerica and Jeff Kalmes, Laboratory Technician – Billerica Wastewater Treatment Plant

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