The $136.5-million Arlington County Water Pollution Control Plant project makes a significant contribution toward improving the environmental outlook for the delicate, imperiled Chesapeake Bay ecosystem.
In addition to expanding capacity from 30 million gallons per day to 40 MGD, the upgrade greatly reduced nitrogen discharges into a river that feeds into the ecosystem. Ten years ago, the plant was discharging 17 milligrams of nitrogen per liter of water into the Four Mile Run River. Today, it is discharging 2.5 milligrams of nitrogen.
The project was executed in two phases. Phase one primarily entailed building two prestressed concrete flow-equalization tanks with a combined capacity of 12 million gallons. Phase two focused on construction of a 30,000-sq-ft filtration and disinfection facility populated by 17 deep-bed de-nitrification filters and two chlorine contact tanks.
The site had an abundance of archaic underground infrastructure, much of it unmapped. The underground uncertainties compelled Fru-Con Construction to install a new conduit duct bank above an existing duct bank. The company created red-dyed concrete sidewalks on the duct bank cover.
Because of limited storage space onsite, two two-acre tracts approximately 5 mi from the jobsite were required. Quarries delivered product to the tracts where it was packaged in 4,000-lb sacks for just-in-time delivery to the jobsite. Fru-Con deployed 2,600 totes filled with sand, 400 filled with rock.
Fru-Con provided value-engineering solutions that produced more than $500,000 in savings for the owner. For example, crews utilized an existing tunnel to carry and house public water and plant effluent water-supply lines beneath an adjacent roadway, eliminating the cost to jack and bore.
The Arlington County Water Pollution Control Plant is one of the first waste water treatment plants in the U.S. to employ the digital serial process control Foundation Fieldbus Communications system.
The plant remained fully operational over the 46-month life of the project, which was part of a 10-year, $568-million modernization and expansion of Arlington’s 73-year-old water pollution control system.
Key Players
Owner: Arlington County – Dept. of Environmental Services
Contractor: Fru-Con Construction Corp.
Construction Manager: AECOM/Earthtech
Architect: Malcolm Pirnie Inc.
Engineer: Malcolm Pirnie Inc.
