January 27, 1998

The Chemical Industry Environmental Technology Projects (CIETP) has begun a program to evaluate the economic feasibility and technological capabilities of two processes designed to reduce wastewater sludge volume and thus significantly reduce disposal costs.

Both processes extract the water from biosludge, the gelatinous, biological solids that remain following the treatment of wastewater. The sludges are then conditioned to allow for their recycle back into the wastewater treatment system.

One process being evaluated is a mechanical cell-rupturing device developed by KADY International of Scarborough, Maine. The proprietary process breaks apart microbial cells in the return activated sludge lines, which facilitates additional digestion and release of bound water in the aeration basins.

The second process is an electrical plasma method developed by Scientific Utilization Inc. of Huntsville, Ala., which sends pulses of electrical current into the sludge, shocking the fluid from the organisms.

"In conventional wastewater treatment, microbes are used to consume waste organics. Consequently, the microbes grow and reproduce, and the excess have to be eliminated. They are gelatinous and it's hard to extract the water from them," said Brad Dunn of DuPont, who is project manager for the evaluations. "Typically the wasted biosludge is first filtered and then pressed, which eliminates some of the water. But there's still significant moisture in the sludge, which costs money for disposal."

Better sludge-volume reduction techniques will reduce transportation and disposal costs.

Battelle, a technology firm based in Columbus, Ohio, is conducting the economic evaluations for CIETP.

CIETP would welcome additional companies to participate in the evaluations.

For more information, contact Charlie Nunn, President, CIETP, 505 King Ave., Columbus, Ohio 43201-2693.