As planned, Dominion Virginia Power has begun a months-long draining of coal ash lagoons into a tributary of the Potomac River and into the James River after agreeing to enhanced treatment of the water discharged at both sites.

The company began drawing water on May 9 from its impoundment at the Possum Point power plant near Dumfries, about 30 miles south of the District of Columbia. It started draining a lagoon at its Bremo Bluff plant southeast of Charlottesville at the end of April.

In the coming weeks, Dominion plans to seek permits from the state Department of Environmental Quality to permanently cap 11 inactive ponds at four of its Virginia power plants. But the permitting process — and the next round of public meetings that will accompany it — has been delayed by recent changes to the federal rule that first triggered the closure of the coal ash ponds.

If, as expected, the court approves an agreement between the Environmental Protection Agency and environmental groups to revise the coal ash rule, companies like Dominion will be required to monitor groundwater around any closed ponds for 30 years— and to clean up any coal ash contaminants that might be detected there.

“We’re hoping that the requirement to monitor and [potentially] clean up groundwater after closure would influence companies like Dominion to remove the waste,” said Lisa Evans, senior administrative counsel for Earthjustice, a national environmental group involved in the settlement. The alternative would be removing it to a landfill lined to prevent leakage into groundwater.

Dominion officials said they intend to pursue their plans to cover the remaining coal ash in the Possum Point lagoon and at Bremo Bluff by early 2018, using a process the company contends would prevent contaminants from leaching into the surrounding environment.

Draining the impoundments at both sites could take up to a year, said Dominion spokesman Dan Genest. Then, the company plans to cover the dry ash left in the bottom of the lagoon with materials intended to keep water away from the waste, and later top it with clean dirt and vegetation.

Many of the environmental groups that complained the state’s water discharge limits were not strict enough have also expressed concerns that the company’s plans to cover the coal ash in place will not keep contaminants from leaking into the groundwater, nearby drinking wells and rivers. They’d prefer to see Dominion remove the remaining ash to one of two landfills in the state that have liners to prevent groundwater contamination.

Genest estimated that removing the ash from the four stations where impoundments are being closed would cost an estimated $3 billion more than the cost of closing the ash in place and would require “about 1.6 million trips with dump trucks on a very narrow road.”

But environmental groups aren’t finished making their case. Advocates and officials are sparring over conflicting tests of well water drawn from homes near the Bremo and Possum Point stations.

One family living near Possum Point has had its well water tested by three separate parties — the Virginia Department of Health, the Virginia Cooperative Extension and a third party contracted by the Potomac Riverkeeper Network — and each test has returned different results. The Riverkeeper’s test found lead at a level 36 times higher than levels that require municipal drinking water systems to take action under federal regulations to protect their customers from harm. The state’s test showed lead levels at just 3 parts per billion, well below the 15 ppb “action” level the EPA has set for public water suppliers. Riverkeeper Dean Naujoks has questioned whether the state conducted its test properly.

Private wells are not subject to EPA standards. But states can set rules to protect users of those wells. Environmentalists contend that even if the lead in a drinking water sample is below the EPA’s threshold, health experts have determined that no level of exposure to lead — a potent neurotoxin — is safe.

Brad McLane, an attorney with the Southern Environmental Law Center, which has opposed the coal ash drainage plans at both sites, helped residents near the Bremo site conduct some of the first well water tests. One of those tests found a small-but-measurable amount of hexavalent chromium, a known carcinogen that in general, is not naturally found in groundwater but is a byproduct of industrial processes, including burning coal. The health department’s response was that none of the metals detected were above the state’s standard for well water.

“Our reaction is, even if you’re within standards, any level of chromium in drinking water is a concern,” McLane said. “If I handed you a glass of water and said, ‘There’s only a little bit of toxic pollution,’ you wouldn’t drink it.”

Dominion responded by referencing a third-party review of health department and private tests conducted on the well near Possum Point. That review by Resource International, Ltd. for Prince William County noted that lead could leach from other sources, such as aging pipes, and concluded that “the Dominion Ash Ponds do not represent a potential source in connection with lead or other constituents identified in the private well samples.”

Dominion has taken steps to be more transparent with local government and other groups — even inviting their input on the next batch of permits before submitting them to the DEQ — after the quick public process for its discharge permits earlier this year drew the ire of local citizens and groups.

Bob Burnley, who served as director of the DEQ from 2002 to 2006, said the department should have brought more of those stakeholder groups, such as local riverkeepers, into the decision-making process before issuing the permits.

“In my humble opinion, that process should have been done before the permits were issued,” he said. “It should have given the big stakeholders more of a role.”

Now, Dominion is trying to do that on its own by working with some of the stakeholders that had once resisted the company’s efforts to drain water from coal ash lagoons into the nearest waterway.

Two of the groups that had opposed Dominion’s discharge permits — the Prince William County Board of Supervisors and the James River Association — were satisfied when the company agreed to treat the water beyond what the state required. They dropped their legal challenges of the permits in March. Dominion signed agreements with each party to introduce “enhanced treatment triggers” for certain contaminants.

The Prince William board’s agreement with Dominion, for example, set trigger limits for six heavy metals, including arsenic, selenium and lead. The thresholds that were written into the company’s engineering plans for the treatment process will flag any water above those stricter limits for more treatment before it is released into Quantico Creek, where those contaminants are of particular concern in the already-impaired waterway. The limit of 100 micrograms of arsenic per liter laid out in the agreement for Quantico Creek, for example, is 77 percent lower than what is mandated by the state permit.

The Potomac Riverkeeper Network is still appealing the permit granted to the Possum Point site. Naujoks contends that the permit sets a dangerous precedent for dozens of other plants in the country looking to decommission their coal ash pits by draining them into nearby waterways.

But Maryland announced Thursday that it has dropped its legal challenge against DEQ the same day that a hearing had been scheduled in the Circuit Court of Richmond. Jay Apperson, spokesman for the Maryland Department of the Environment, said changes the DEQ, Dominion and the EPA have made to increase wastewater treatment protections and long-term monitoring have assured them that the closure of coal ash ponds will not harm the Potomac River, which belongs to Maryland.

“Maryland is supportive of recent agreements in Virginia to increase wastewater treatment protections and monitoring protocols,” Maryland Secretary of the Environment Ben Grumbles wrote in a statement that mentioned “ongoing discussions with Virginia and Dominion to do even more testing for fish tissue, water quality and sediment in the river beyond the current testing and monitoring in current or soon-to-be-proposed permits.”

Apperson said Dominion’s commitment to treat the water to a higher degree than the permit initially required is one reason for the change of heart, as well as the EPA’s recently changed rule that will require longer monitoring of closed coal ash impoundments. He said DEQ also has pledged to draft a “stringent and comprehensive” solid waste permit for Possum Point, required to seal the ash in place, and to include Maryland in the process to ensure that it is protective of Quantico Creek and the Potomac River.

The two states are also discussing an agreement that would result in increased monitoring for the river that includes sampling fish tissue, water quality and river sediments “as part of Virginia’s holistic approach to protecting the river.”

Jason Williams, Dominion’s environmental manager overseeing the discharges at both sites, said the treatment process currently being used ensures that “everything that is released into Quantico Creek is protective of Quantico Creek.”

During a tour of the Possum Point lagoon after draining began, Williams explained how the treatment system installed there will remove and clean an estimated 200 million gallons of wastewater before the company begins to seal the ash in place.

The equipment assembled to filter coal ash constituents from the lagoon’s water stretches the length of a city block. Williams said the setup is similar to the one being used at Bremo Bluff near Charlottesville.

All of the water in the Possum Point lagoon, including the rain that has fallen frequently this spring, will go through the first of two-treatment processes before being delivered to a holding tank and then to Quantico Creek, Williams said. If a batch of water does not meet the stricter limits the company and other parties have agreed to, it will go through a second, more intensive treatment.

The company said it conducted closed-loop tests of the system for several days before the discharges began to ensure that the process ran smoothly. A third-party lab hired by Dominion conducted tests.

After infusing the water with oxygen and adjusting its pH, or acidity, it is dosed with “flocculants,” chemicals that get particles to settle out of the water. The water then moves through “geotube” filter bags that capture more sediment, which is periodically removed to landfills.

Additional filters remove minute particles from the water that are up to 1 micron in size, smaller than the width of a human hair.

Williams said the company plans to run all of the water through the first step of the enhanced treatment process, which entails injecting a chemical to remove arsenic and selenium. Only water that is flagged for additional treatment will go through the final process, using ion exchange to remove other contaminants such as aluminum, barium and lead.

The finished treated water then goes to one of two holding tanks that function “as a safety net, to make sure the water’s been treated and tested,” Williams said.

As the water is pumped from the holding tanks into a black pipe that stretches to Quantico Creek, it goes by one more valve that could redirect any water that doesn’t meet testing limits back into the lagoon.

The 79-acre lagoon now contains water pumped into it from four other impoundments at the Possum Point plant. Dominion plans to remove the ash in the bottom of the other ponds and deposit it in the dry bed of the largest, clay-lined impoundment, where the company intends to seal it all.

Dominion and its contractors are testing the water and reporting weekly results to the DEQ. The company also plans to make its test results public, posting them at www.dom.com/coalash. The first test data from the Bremo plant are already posted.

Even with the promise of enhanced water treatment, Naujoks said one of the main reasons his group didn’t drop its lawsuit over the discharge permit is that the treatment process doesn’t come with as much oversight as his group would like.

“This is going to go on for a year, and as this [water] draws down, the closer to the ash, the more metals. Who’s going to be watching this treatment? They are,” Naujoks said. “So we have to just trust that, over the next year, Dominion is going to do the right thing.”