The Alexandria Renew Enterprises WRF Successfully Transitions from Methanol to a Non-Hazardous Carbon Source (MicroC 2000™) While Maintaining Low Level Nitrogen Removal Performance

The Alexandria Renew Enterprises (AlexRenew) advanced Wastewater Reclamation Facility (WRF) is a 204,000 m3/day average daily flow (54 million gallon per day (mgd)) advanced wastewater treatment facility that is located in Alexandria, VA and discharges treated effluent into a tributary of the Potomac River. The AlexRenew facility is part of the Chesapeake Bay Total Maximum Daily Load (TMDL) for nutrients discharged into the Chesapeake Bay Watershed. The facility is currently being upgraded to meet an annual average total nitrogen (TN) waste load based on a concentration of 3 mg/L at its design capacity.In April 2011, the AlexRenew WRF began the upgrade of its existing methanol storage and feed system as part of the State-of-the-Art-Nitrogen-Upgrade Program (SANUP). During the construction, AlexRenew could no longer safely use methanol as its supplemental carbon source to maintain its effluent nitrogen permit limit as the existing methanol facility was taken offline for the upgrade. AlexRenew selected MicroC2000™ as the most cost effective, readily available, non-hazardous supplemental carbon source to replace methanol during the construction phase.This paper is a two phase case study wherein the first phase evaluates the facility's nitrogen removal performance as it transitioned from methanol to MicroC2000™ and a comparative analysis of the plant's nitrogen performance while doing so. The second phase of this paper will consist of observations in improved biological phosphorus uptake during the time in which the plant utilized MicroC2000™ as its supplemental carbon source for denitrification.