Water Treatment Plant 1

A group of three dozen Arlington seniors toured the county government's Water Pollution Control Plant on March 29, 2013, getting an up-close view of how the county disposes of 40 million gallons of wastewater each day. (Photo by Scott McCaffrey)

Arlington County Board members on July 18 are expected to agree to sell to George Mason University nutrient credits over a six-year period.

Because of upgrades, the Arlington Water Pollution Control Plant emits less nitrogen and phosphorous than allowed under its discharge limit, and is able to offer credits to other plants that are over their limit.

GMU officials recently contacted the county government to purchase credits; state officials have given preliminary approval to the proposal.

“Similar private agreements may be negotiated in the future,” county staff told County Board members in a memo recommending approval of the proposal.

Arlington officials expect the sale of credits to generate about $3,720 per year, or about $24,500 through 2021, when the agreement will terminate.

County officials say that even with the sale, “a comfortable margin” exists should the treatment plant ultimately release a higher amount of nitrogen and phosphorous than expected.

The private sale to GMU is separate from the county government’s participation in the Virginia Nutrient Credit Exchange, which allows participating jurisdictions to buy and sell credits among themselves.