BIOLOGICAL TREATMENT OF DE-ICING AGENTS AND STORMWATER FOR RUNWAY 1L-19R AND ASSOCIATED TAXIWAYS, WASHINGTON DULLES INTERNATIONAL AIRPORT

The Metropolitan Washington Airports Authority is planning to construct a fourth runway and associated taxiways and accompanying service roads at Washington Dulles International Airport (future Runway 1L-19R). The stormwater management system for the future runway system and de-icing pad is being designed to take into consideration environmental resources, stormwater regulatory requirements, and long-term airport operational needs. The proposed stormwater treatment system is being designed to detain stormwater for treatment through passive biological systems for removal of biochemical oxygen demand (BOD) from fugitive deicing materials and total phosphorus (TP).Low-Impact Development (LID) concepts are incorporated into the design to meet Virginia Department of Environmental Quality (VDEQ) water quality requirements. The principles of LID require that runoff be minimized by promoting infiltration and treatment onsite or as near to the source as possible. This approach is increasingly advocated by regulators and reflected in changes in professional practice.This paper describes the methodology used to determine the size and components of the stormwater treatment system. Water quality treatment projections are provided based upon available published information and assumptions of flow and constituent loading. Construction, operation, and maintenance requirements are summarized.