Dec 28, 2000

Media Filters Reduce Biocide Costs at Dairy

Gehl Guernsey Farms is a 100-year-old dairy in Germantown, Wis. Gehl manufacturers specialty products such as cheese sauce for nachos and nutritional drinks such as Gehl Cappuccino.

Cooling System Problems
Cooling for the food products is done with cooling towers and heat exchangers. Water flow rates vary from 8 to 1,200 gpm. Michael Sowieja, vice president of engineering, and Steve Sadowski, plant system coordinator, watched as their cost of maintaining good water quality was increasing. Their cooling towers were showing as much as 18 pounds of dirt and debris and the operating people had to drain the towers and shovel out the dirt three times per year. In addition, using dip slide tests to check the bio-counts, Gehl was using six drums of biocide chemicals per year at a cost of $1,500 per drum.

Mike and Steve analyzed several types of equipment to solve the dirt problem including screen filters, disposable cartridges, centrifugal separators and media filters. The particle size distribution of the contaminants in the systems was 90 percent at 10 microns and less so the selected equipment had to be able to remove this size of particles. While cartridge filters could clean up the problem, they were extremely costly in terms of operating and maintenance. Centrifugal separators were not selected, as this technology does not have the required removal efficiency. Sowieja and Sadowski worked with Dave Hammer of Chipley and Zeman in Milwaukee, Wis., and selected and installed a PEP SMF-FG-24 media filter from Process Efficiency Products, Inc., on the remote sump.

Within the first month of operation, the bio-counts were reduced by 50 percent and Gehl reduced its use of biocides. In fact, Gehl reduced the usage from six drums per year to two drums at a savings of more than $6,000 for the chemicals alone. The June bug problem that helps to drive up the use of biocides was reduced by the PEP media filters.

Sowieja and Sadowski stated that "cold water is very important to cooling the cheese, and the cost of maintenance to keep the water cold can be very expensive." In other words, water is cheap, but to treat it can be expensive. Gehl has now installed two additional filters on the other cooling tower sumps with similar results.

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This article was contributed by Process Efficiency Products, Inc.