Virginia doesn’t have the massive droughts that some parts of the United States do, but it has exactly the same water problems. Homes and businesses in the Hampton Roads area in the southeastern corner of the state are pumping groundwater faster than it can. Replenished. In some places the situation is getting worse as the earth is sinking.
But officials believe they may have found a solution in the sewers. Every day, the area’s sanitation system receives one million gallons of treated wastewater and pumps it back into the Potomac Aquifer, the area’s primary source of drinking water. And there are plans to increase that to 100 million gallons in the next few years.
Cities and towns across the country are increasingly turning to wastewater treatment to increase the supply of drinking water. The number of drinking water reuse projects has quadrupled in the last 20 years. according to the data It was collected by the National Alliance for Water Innovation, a research program funded by the U.S. Department of Energy.
said Michael Kipalski, director of the Wheeler Water Institute at the University of California, Berkeley.
For coastal Virginia, the goal is to stabilize groundwater to address two increasingly urgent problems. First, the ground is slowly sinking and collapsing in places due to groundwater depletion.
Households and industries in the region pump approximately 155 million gallons of groundwater daily. In confined aquifers like the Potomac River, subsurface impermeable clay and rock layers make it difficult for rainwater to seep into the ground, and natural replenishment is much slower.
Even if people stopped pumping groundwater today, it would still be thousands of years before the aquifers would refill, said Mark Bennett, who runs the Water Science Center in Virginia and West Virginia at the U.S. Geological Survey. said it is possible.
During that time, if there is not enough water to support the ground, the underlying sediment will fall off and the surface will collapse.
The second major problem is that as more and more freshwater is pumped out, pressure is lost and more dense seawater seeps underground, making aquifers susceptible to saltwater pollution. .
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We are facing drought. Stories of Holland’s long struggle with excess water are written all over the marshes. Now that climate change has dried up water, the Dutch hope to blaze a trail to safety again – only this time by figuring out how to retain water rather than flush it out.
In low-lying coastal areas like Hampton Roads, climate change is exacerbating the problem. This is because as the temperature rises, the volume of seawater expands and sea level rises. Also, land-based glaciers are melting at a faster rate, adding even more water to the ocean.
All of this leads to increased flood risk and helps salt water invade freshwater sources.
Many cities in the Hampton Roads area, such as Virginia Beach and Norfolk, average less than 10 feet above sea level. Over the past 100 years, sea levels in the region have already risen nearly 18 inches. according to the data From the National Oceanic and Atmospheric Administration.
In response to the growing threat, the Hampton Roads Sanitary District, which manages the area’s wastewater, began taking a more direct approach to groundwater replenishment in 2018 with a project called the Sustainable Water Initiative (SWIFT). I was.
While other water agencies around the country, such as California’s Orange County Water Department, inject treated wastewater into underground aquifers to act as a barrier to seawater intrusion, this project It was the first effort to do this in .
In fact, the state did not have a regulatory framework to oversee the injection of water into the ground. As such, sanitary districts had to push for legislation to carry out surveillance. Dr. Kipalski said this is an unusual situation. Because it’s rare to see water districts calling for more regulation.
Currently, the district’s sewer system captures wastewater and sends it to a wastewater treatment plant to remove nutrients and bacteria.
Then, every day at the SWIFT Research Center in Suffolk, Virginia, 1 million gallons of water are disinfected to remove harmful contaminants and pathogens and undergo additional treatments to make the water drinkable. Advanced treatment plants also adjust things like acidity and dissolved oxygen levels to make the water suitable for the aquifer.
It’s essentially a “foolproof drinking water plant,” said Charles Bott, the district’s director of water technology and research.
Treated water enters the Potomac Aquifer via a 12-inch diameter recharge well and is discharged intermittently between 500 and 1,400 feet below ground. Aquifers act as environmental buffers, basically providing another level of treatment as water slowly filters through the soil. This is a process that can remove some pathogens and trace contaminants.
By 2032, the district will treat up to 100 million gallons of wastewater daily, pump it into an aquifer and discharge it into the Elizabeth, James or York rivers.In addition to reinforcing the aquifer, the project, when fully implemented, will 90% of district wastewater discharge.
Turning wastewater into potable water is expensive. The next full-scale SWIFT plant, which will process up to 16 million gallons of wastewater per day, is expected to cost more than $650 million, partially financed by customer fees and loans from the Environmental Protection Agency. It is This does not include maintenance and day-to-day operations that cost an estimated $7.2 million annually.
However, sanitary districts have calculated that more intensive treatment of wastewater could reduce the costs of complying with regulations. getting tougher A regulation that regulates pollution from hundreds of treatment plants that regularly discharge wastewater into the Chesapeake Bay.
Planners expect the rules, which are primarily focused on excess nutrients that can harm marine life, to become more stringent over time, said Hampton Roads district chief of technical services. Jamie Mitchell said. It’s not cost-effective to make incremental upgrades “every five or ten years to deal with new regulations,” she said.
So far, the system appears to be in a “win-win-win situation,” according to Dr. Kipalski. This is because it addresses a variety of issues, including land subsidence and saltwater intrusion, nutrient contamination of the Chesapeake Bay, and increased costs to the district.
The project is still in its early stages, but researchers from the U.S. Geological Survey have already noted slight improvements in the aquifer.
Not so long ago, such an idea would probably have been dismissed as too costly and unpleasant. For example, efforts to develop water recycling in San Diego and Los Angeles in the 1990s were thwarted by activists who denounced what they called a “toilet-to-tap” system.
Today, the growing acceptance of wastewater reclamation projects is being increasingly considered by local governments facing pressures on water supplies from climate change and population growth, even in areas where drought does not last long. It reflects the calculations that have to be done.
Other drought-hit states such as California and Texas have similar projects, in some cases imposing mandatory water restrictions on homes and businesses to reduce water consumption. Some even send the treated wastewater directly for use as drinking water, without environmental buffers such as aquifers.
One of the great advantages of wastewater is that it always has a reliable supply, says Dr. Kiparsky. He said using it to recharge aquifers is a complex but effective way to achieve the basic goal of returning water to its original place.
“It’s closing the loop on the city’s water cycle,” he said.