The Oxidation Ditch in Dahlgren VA (1.0 MGD, 4 ring) was upgraded using Entex’s IFAS Webitat system to achieve stringent total nitrogen limits after a successful pilot study.

Ten Webitat modules with BioWeb fixed media were installed in the anoxic zone of the outermost ring of the ditch in 2014. Each year since the installation, the TN limits have been met with large safety margins. In 2017, Dahlgren released only 1,966 lbs of TN, well below the permit limit of 9,137 lbs.

Application

1.0 MGD Oxidation Ditch Retrofit for TN control

Entex Solution

Ten Webitat modules installed in anoxic outer ring

Results

Met stringent TN limit all 5 years of operation

2017 average TN Effluent = 2.8 mg/L

Download: Dahlgren, VA Webitat Case Study