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Brown and Caldwell, Columbus Water Works Earn Top International Award for Green CBFT3

ATLANTA-(Business Wire)-September 3, 2008 - The International Water Association today announced national environmental engineering firm Brown and Caldwell and the Columbus (Ga.) Water Works won the 2008 Global Project Innovation Superior Achievement Award for their work on the Columbus Biosolids Flow-Through Thermophilic Treatment and Cogeneration System Project.

The award will be presented at the IWA World Water Congress and Exhibition in Vienna, Austria, on Sept. 10. Cliff Arnett, CWW senior vice president of operations, and BC’s Principal Investigator John Willis and Project Manager Randy Shaw will be on hand to accept the award.

“This is great news for BC and the Columbus Water Works,” says Denny S. Parker, Ph.D., P.E., the company’s director of technology. “Our people are the best when it comes to originating innovative technology that promotes sustainability.”

To retrofit an existing wastewater treatment plant with anaerobic digesters, the Columbus Water Works and BC used first-of-its-kind engineering to develop the CBFT³ process to convert the existing mesophilic digestion process to low-cost, Class A thermophilic digestion and produce Class A biosolids. The CBFT³ reduces required batch processing times from 24 hours to 30 minutes, saving CWW approximately $3 million in capital costs.

Cogeneration is being implemented that incorporates state-of-the-art, lean-burn engine-generator technology to produce about 40 percent of the treatment plant’s electricity demand (Green Power) using biogas (digester gas) that would otherwise be flared. These new engines offer roughly 20 percent more power than previous generation engines or 60 percent more power than microturbines with low exhaust emissions.

The CBFT³ and Cogeneration project is under construction and represents the culmination of more than six years of research and engineering evaluations that will advance anaerobic digestion.

“The project is revolutionary in that it is the first thermophilic anaerobic digestion process in North America to be run entirely off heat derived from digester-gas fueled power generation,” says Willis. “Coupled with other gains, generation of this Green Power will result in a net carbon-offset of 9,500 metric tons as CO₂ per year for this 40-mgd treatment facility.”

Other green innovations include:

using all of the biogas from digesters to generate renewable thermal and electrical energy
heating the raw solids by first using heat recovered as digesting thermophilic biosolids are cooled to mesophilic temperatures in the TPAD system
continuing to heat solids to thermophilic temperatures and maintaining digesters at this level using heat recovered from the engines used to generate power
treating digester gas to remove water, siloxanes, hydrogen sulfide, and particulates to levels required for the advanced engine-generators

The project also won the IWA’s 2008 grand prize in the Applied Research category, as well as the grand prize for research in the American Academy of Environmental Engineers’ Excellence in Environmental Engineering awards competition in 2007.

Brown and Caldwell is a full-service environmental engineering firm that has been designing and implementing sustainable solutions to complex environmental problems for more than 60 years. The employee-owned company is headquartered in Walnut Creek, Calif., and employs more than 1,600 people in 45 offices nationwide. Engineering News-Record ranks Brown and Caldwell 48^th among the nation’s top 500 engineering firms, 36^th among the Top 200 environmental firms, 21^st largest in the Water Supply market and 8^th largest in the Sewer/Waste market.

Project description on the IWA site: www.iawq.org

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