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City of Northfield New Wastewater Treatment Facility Wins 3 Awards

The Northfield Wastewater Treatment Facility Modifications and Expansion has been honored with 3 Awards. The American Council of Engineering Companies (ACEC/MN) awarded the City with a 2003 Grand Award. The project also won the Project of the Year as presented by the City Engineers Association of Minnesota (CEAM) as well as a 7 Wonders of Engineering Award from the Minnesota Society of Professional Engineers (MSPE).

Northfield's upgraded wastewater treatment facility incorporates a new system destined to help advance wastewater treatment technology in the United States.

In 1997, the city of Northfield hired the engineering firm of Bolton and Menk, Inc., to evaluate wastewater treatment alternatives for the city's wastewater treatment facility. The facility is located on a small peninsula along the Cannon River and offered little space for facility expansion. In addition, the Cannon River is classified as an Outstanding Resource Value Water, placing strict discharge limits on the facility ‹ limits that would not be attainable without a significant upgrade of the existing facility.

To meet the rigorous new wastewater treatment standards while economically achieving the city of Northfield's short- and long-term wastewater treatment goals, Bolton & Menk, Inc., developed a plan using an advanced technology -Biological Aerated Filters (BAF) and parallel plate clarifiers for wastewater treatment, and lime heat stabilization for biosolids treatment. BAF is a submerged media upflow filter that provides a biological conversion of organic matter and the physical capture of solids on media. It efficiently provides biological treatment in a fraction of the space required by traditional U.S. wastewater processes and is considered the best technology available today.

The use of this new technology proved both practical and cost effective, yielding several advantages over conventional wastewater plans. For example, the compactness of the advanced system allowed reuse of the site, saving the city millions of dollars in capital investment. By carefully staging construction of the new facilities, the existing plant was able to maintain operations over the course of nearly two years while the new facilities were built. The system reduces Biochemical Oxygen Demand, ammonia and phosphorous below standards. The reduced size of the facilities also allowed for a comprehensive odor treatment system to be installed, meeting environmental requirements for odor control.

The city of Northfield's new wastewater treatment facility efficiently complies with the stringent wastewater discharge limits for the Cannon River. The facility will meet the city's needs for the next 20 years, and has an expansion option to 40 years.

BAF technology, along with parallel plate clarifiers, provides biological treatment in a much smaller space than required by traditional U.S. wastewater processes and will help solve the complex space issues facing municipalities and engineers today and in the future.