Tuesday, March 8, 2016

It's Time For the Treatment

Dominion coal ash wastewater debate centers on treatment
Dominion Virginia Power's plan to release hundreds of millions of gallons of coal ash waste water into state waterways has sparked a protest by hundreds at the Capitol, the arrest of eight and court action to block the utility's plan. The opposition stems from concerns that water at former coal-burning power plants will not be properly treated before it is discharged into public waters. Dominion contends it will be. Following is a look at what is pushing this issue to the forefront, how the power company plans to treat the waste water, and the concerns of environmental groups.

Dominion contends the coal ash wastewater it intends to discharge actually amounts to a thimble compared to the volume of water in the James and the Potomac, and that its treatment regimen will not harm marine life. Jason Williams, who manages Dominion's water and waste systems, outlined a treatment system that includes multiple screenings, holding tanks and other measures aimed at removing heavy metals and sediment from the water before it is released. Here's an abridged version of the treatment:
You only need to look at Possum Point on Google Earth to see that the amount in the treatment ponds is trivial compared to the volume in the nearby Potomac River.
Water pumped from the ponds is drained at a slow pace to remove sediment and ash. With the water stored in holding tanks, oxygen is pumped. That has the effect of settling solids such as metals. A second step increases the pH, or acidity, level of the water, which essentially has the same result. Then more metals are removed when the water goes into a series of tanks with what is called a flocculent — "What this does is this chemical makes them all stick together," James said of the metals and sediment. "Once they're stuck together, you get a sludge that you can collect."
A pretty standard treatment for arsenic. It's fairly difficult to remove from water, because it's not as "sticky" as many other metals. On the other hand, despite its bad rap (caused almost entirely by the play "Arsenic and Old Lace"), arsenic is not nearly a toxic as many pollutant metal, and even some necessary nutrient metals, like selenium.
The next steps put the water through a series of filters with finer and finer membrane, and from there the water goes into tanks before adjusting downward the pH level. A high pH level could harm wildlife in the river. The final step returns the water to a series of tanks where the water is sampled to ensure metal concentrations are within state-permitted limits. "The permit limits are set so to ensure that the water going in is as same as the river or better," Williams said. Once the discharges begin, Dominion is required to sample the waste water three times a week and report to the state if discharges exceed limits. That would also temporarily halt dewatering until a corrective plan was in place.
That's an insanely high standard.
The gap between Dominion's dewatering plans and the demands of environmental groups boil down to acceptable levels of heavy metals in the discharged waste water. They are convinced Dominion can narrow that difference through more stringent treatment. They also are seeking testing of fish tissue during the wastewater releases to see if toxic metals are accumulating in the tissue.

Brad McLane is a senior attorney at the Southern Environmental Law Center, which has gone to court on behalf of James and Potomac protection groups to seek more stringent state environmental controls during dewatering. He doesn't agree the discharges amount to a thimble-full of water in vast water systems. "We're talking about toxic metals that are harmful to aquatic life and are carcinogens," he said. Despite the criticism, McLane said he has reviewed Dominion plans at Bremo and calls them encouraging. The group's real beef is with the DEQ, he said. "Ultimately our dispute is with the DEQ for setting lax limits," McLane said.
Numbers don't mean anything to a person devoted to a religious view of humans as bad, and nature is fragile. 'Sola dosis facit venenum''

The best thing for nature in this case, is to get rid of the toxic ponds as quickly as possible. They are hurting the environment more as attractive nuisances than they would be if they were simply to be slowly bled into the Potomac and paved over. Treatment would a bonus.

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