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Installation of Granular Activated Carbon (GAC) Filtration Systems

The flurry of activity at our Shelter Rock Road plants since March will end in June when the installation of Granular Activated Carbon (GAC) filtration systems are completed.

Water Commissioner Kenneth Borchers explained, “A total of four GAC filters were recently installed, two each at Plant 7 and at Plant 10. This technology will treat emerging contaminants in our water by the process of adsorption. Construction is being done simultaneously since the plants are adjacent to one another. This will expedite installation, minimize potential interruptions and we can take advantage of economies of scale. It’s a win-win situation.”

How Does GAC Work?

Granular Activated Carbon (GAC), which can be derived from wood, peat, coal, lignite or even coconut shells, is a remarkable substance with a unique pore structure consisting or micro-pores, meso-pores and macro-pores. Unlike the process of absorption where atoms, molecules or ions actually permeate a liquid or solid, in adsorption the atoms, molecules or ions form a film and adhere to the surface of the liquid or solid without penetrating. To put it into persepective, 10 grams of granulated activated carbon, (less than a third of an ounce), has a surface area equal to a standard NFL football field. That porosity is why GAC is ideal for eliminating emerging contaminants in water.