Sustainable Water Initiative for Tomorrow (SWIFT) Project in Hampton Roads

The Hampton Roads Sanitation District (HRSD) has committed to spend $1 billion for an innovative solution to two problems. In 2017, wastewater from all but one of the district's 13 treatment plants was discharged into the Chesapeake Bay or a tributary. That wastewater carried too much phosphorous and nitrogen into the bay, adding to the excessive levels of nutrients that resulted in low levels of dissolved oxygen.

In addition, extraction of groundwater in the region (especially for paper mills at Franklin and West Point) had led to ground subsidence. The lower elevation was significance enough to increase the predicted destructive impacts from future sea level rise, and to increase the threat of saltwater intrusion into the bottom of existing wells. Sea level was rising 4 millimeters a year, the second-highest level of sea level rise in the United States after New Orleans. Continued subsidence would result in greater damage to local infrastructure in times of high water, such as king tides.

The innovative solution was to treat wastewater to drinking water standards, then inject it deep into the Potomac Aquifer. Reinjecting the water would eliminate discharge of nutrients (and pharmaceuticals still in the wastewater) into the bay. At the same time, injecting 120 million gallons a day would increase pressure in the aquifer to offset the effects of groundwater withdrawal. The natural recharge rate was far below the amount being withdrawn, estimated at 144 million gallons a day.

The $1 billion price tag was staggering, but alternative ways to reduce nutrient pollution and Save the Bay could have been even more expensive. Wastewater treatment plant upgrades could match the success of Northern Virginia plants, upgrading to maximum feasible treatment technology in order to reduce nitrogen levels to 3mg/l. However, the space available at different plants for new tanks required for additional nitrogen removal capacity was limited. Another likely alternative was to reduce stormwater runoff into local creeks, but the land and cost required to build stormwater ponds would not be cheap.

Thought wastewater would be treated to drinking water standards, it would not be re-used for that purpose. The proposal by Newport News to build the King William Reservoir revealed that there was an adequate supply of drinking water. The Hampton Roads Sanitation District had no market for the water, but injecting it would create an underground reservoir that localities might tap in the future. 1

Links


Wastewater Reuse: Eliminating Discharge to "Receiving Waters"
Sewage Treatment in Virginia
Virginia Places