Carbon Fiber Wheel Fan Design Controls Odor Emissions in Wastewater Treatment Plant

Odors were the primary concern for a wastewater treatment facility in Des Moines, Iowa. Existing stainless-steel fans had been in place for over 30 years, and with that came chemically induced corrosion and odors.

New fans had to fit into the existing space, and motors could not exceed 100 horsepower (HP) or emit any odors. Changing the HP was not possible, as it would require additional renovations and costs in rewiring and time. Noise was also an issue, as the treatment plant is located in a residential area, and noise levels are enforced by ordinance.

The new fans had to meet increased corrosion resistance, form factors, HP ratings, low noise, 23,000 CFM volume, 18 inches of static pressure, quieter operation, ease of installation and maintenance, and high reliability.

Two BCF 330 fiberglass fans from Aerovent helped solve the problem. Other types of fans would have to use fiberglass and stainless steel in combination to obtain the required speed and performance. However, Aerovent fans were able to meet and exceed the performance requirements with fiberglass and carbon fiber wheels.

Aerovent’s 33-inch, centrifugal, backward-curved, high-pressure fans are specifically designed for handling corrosive or caustic air in high-pressure applications where conventional steel and stainless fans are not suitable. The BCF’s carbon-fiber-reinforced wheel is designed for maximum efficiency, quiet operation, minimal weight, and optimum strength. Further, a wide wheel and housing produce high-volume, low-velocity air movement.

The two BCF fans installed at the wastewater treatment plant are identical, except for rotation. One of them has a clockwise rotation, while the other has a counterclockwise rotation. Because of the space and ductwork configuration constraints, one of the fans had to have an opposing rotation to fit the existing duct layout.

With regard to operation, the old fans ran at 100 percent all the time. However, with Aerovent’s BCF fans, run times average 50 percent less (it takes less energy to move more air with less vibration).

The 100-percent wheel width of Aerovent’s BCF fans easily produces the required 23,520 CFM at 18 inches of static pressure. Speed of each belt-drive fan is around 2,200 rpm. (A direct drive fan at 1,800 rpm motor would have to be an over-speed, or a 3,600 rpm motor would need to run slower.)

The Des Moines wastewater treatment facility is continuing to be a good neighbor by controlling odor emissions with Aerovent’s corrosion-resistant fiberglass/carbon fiber fans, which exhaust clean air into the atmosphere.

For more information about Aerovent’s carbon fiber wheel design and other products, visit www.aerovent.com, or call 763-551-7500.