MBBR and IFAS Pilot Program for Denitrification at Fairfax County's Noman Cole Pollution Control Plant

As part of a nutrient reduction program, developed to meet new Virginia ENR requirements, two innovative denitrification technologies were piloted at the Noman Cole Jr. Water Pollution Control Plant in Fairfax County, Virginia. The first technology was a Moving Bed Biofilm Reactor (MBBR). The second technology was a modified Integrated Fixed Film Activated Sludge (IFAS) process. These studies have shown that both technologies can be used for denitrification at the plant. Each was shown to be easily capable of reducing the pilot influent NOx-N of 7 mg/L to below 2 mg/L NOx-N at the loadings studied. The MBBR system was shown to be sensitive to influent ortho-phosphate levels below 1.0 mg//l. Only about 1.25 gm of excess TSS was produced per gm of NOx-N removed, in the MBBR system.