The Treatment System

Pond 5

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The fifth pond in the treatment system is a Vertical Flow Pond, also called a Sequential Alkalinity Producing System, or SAPS. Below about two feet of water is a thick layer of organic material and then about four feet of limestone. The bottom of the pond is lined with numerous drainage pipes. AMD flows through the layer of compost and is stripped of oxygen by the decaying organic material, then through the thick limestone layer, significantly raising its pH without depositing any metals, then out through the bottom discharge pipes into the next pond. This vertical flow process helps to prevent the iron and other metals from coating the limestone, making the AMD treatment system more efficient and long-lasting.

« Ponds 2–4

Pond 6 »