Little Bubbles, Big Payoff

by Kneeland A. Godfrey, Jr., Sr. Ed.; Civil Engineering Magazine, ASCE World Headquarters, 345 East 47th Street, New York City, NY.,

Serial Information: Civil Engineering—ASCE, 1987, Vol. 57, Issue 5, Pg. 86-89

Document Type: Feature article

Abstract: Fine poor diffusers often boost the energy-efficiency of aeration in sewage plants by 25-50%. This is important because the combined energy bill of all U.S. municipal sewage plants is several hundred million dollars a year. A case history of a recent installation of fine-pore ceramic diffusers at the Albuquerque, N.M. plant reports that the $1 million cost of the installation was paid back in three years. Also, 14,500 of a newer type of diffuser, the PVC flexible membrane or tube type, were installed at the Renton plant of Seattle. Reportedly they are 25-30% more energy efficient than the old, coarse-bubble diffusers they replace. The fine-pore diffusers have not been installed in as many industrial wastewater plants as municipal plants. The wastewater organic loadings in the latter are typically higher, and the sludge ages differently. These are thought to be among reasons why the fine-pore diffusers tend to clog in industrial plants. But the Courtland, Ala., plant of Champion International has had 31,000 fine-pore ceramic diffusers in service for 3½ years with little clogging or head-loss problem.

Subject Headings: Waste treatment | Bubbles | Diffusion | Aeration | Sewage |

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