Why do Carrousel® systems meet low nutrient limits so consistently?

The power turndown of the Excell® aerator can reach 90%, so DO (dissolved oxygen) control even at low flows is no problem. Preventing overation is the key to good, consistent biological nutrient removal, and lack of power turndown is a reason so many other systems fail or need large amounts of chemicals to make up for this deficiency. In addition, the free internal recycle (with no pumps) from the aeration zone to the anoxic zone can reach very high values (IR/Q can be >10), allowing for large denitrification rates.