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Consol treatment plant: the cost to coal of clean streams

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Reverse osmosis cylinders are the core of Consol Energy's new Northern West Virginia Water Treatment Plant outside Mannington. Reverse osmosis cylinders are the core of Consol Energy's new Northern West Virginia Water Treatment Plant outside Mannington.

In Marion County on July 11, Consol Energy unveiled what may be the future of coal.

Its new Northern West Virginia Water Treatment Plant outside Mannington treats 3,500 gallons per minute of polluted discharges from the company's Blacksville, Loveridge and Robinson Run mines in Monongalia, Marion and Harrison counties.

The NWVWTP is enabling streams in the Monongahela River watershed to recover from decades of mine discharges. According to the company's educational video, it will be "an industry benchmark for mine water management."

Long time coming

The plant is the result of a March 2011 court settlement. In that settlement, Consol took responsibility for its role in a 2009 golden algae bloom that killed most of the life on 30 miles of Dunkard Creek at the West Virginia-Pennsylvania border.

An investigation determined the fish and mussel kill was caused primarily by wastewater high in total dissolved solids, or TDS — salts, essentially — from coal and coalbed methane production. Consol had been putting salty discharges into Dunkard Creek from its Blacksville No. 2 and other mines for decades. The state Department of Environmental Protection eventually established water quality standards for chlorides, a component of TDS, and had been engaged with the company since 2002 in a series of actions and negotiations over the company's failure to meet the resulting permit limits.

It's not an easy problem to solve. Dissolved solids in waste fluids are a particular challenge for fossil fuel producers — for underground coal mines where water is pumped out, in this instance, and similarly for natural gas producers in hydraulic fracturing flowback and produced water. Suspended solids, which can include metals and sediment, can largely be settled or filtered out at relatively low expense. But removing dissolved solids requires far more expensive methods.

In the March 2011 settlement with the U.S. Environmental Protection Agency, the company agreed in part to build a state-of-the-art reverse osmosis system to treat discharges from its mines in the region that couldn't meet their permit limits for chlorides. The company also committed to monitor Dunkard Creek and time its discharges to keep the saltiness under control until the mandated May 2013 opening of the new treatment plant.

It's hard to treat mine water

The NWVWTP went into operation on schedule. The plant's zero-liquid-waste process removes suspended solids, then dissolved solids through multiple levels of treatment.

Discharges undergo initial pretreatment at the three mines to remove some suspended solids before traveling through 34 miles of pipeline to the facility. That wastewater enters a 3 million gallon-tank and is mixed to ensure consistent characteristics as it enters processing.

Then it's further pretreated in several steps. It's aerated, chemicals are added, metals are settled out, the pH is adjusted and more metals settle out, then it's filtered once and filtered again before hitting the reverse osmosis membranes.

"Everything up to here is to protect the RO system," said project manager Klete Kutrovac. The reason is that reverse osmosis is a gold standard of water treatment: very effective, and very expensive. This plant cost $130 million and, even with careful maintenance, the costly reverse osmosis membranes have to be replaced every three to five years.

Of the 5 million gallons of wastewater that enters the facility each day, 85 percent comes through RO so unnaturally clean that it would not be good for aquatic life, according to Director of Water Systems and Operations John Owsiany. Minerals have to be added back in before the "product water" can be discharged to nearby Hibbs Run Reservoir.

But treatment is not done yet.

"Everything beyond this is where this facility goes above and beyond any other," Kutrovac said.

The 15 percent sludge that's rejected by the reverse osmosis filters is concentrated and salty, with seawater-level TDS of 30,000 parts per million. After distillation in an evaporator and crystallization, TDS is more than 200,000 ppm — nearly as salty as the Dead Sea. Dewatering through a plate and frame press converts that to dry cakes of salts.

The two process lines — the removal of suspended solids before reverse osmosis and the removal of dissolved solids from the RO reject — produce two streams of solid waste. They amount to about 100 tons per day of sludge and 150 tons per day of salts. A staff chemist estimated off the top of his head that less than 20 percent of that volume is chemicals added at the plant. That would mean more than 80 percent is pollutants that no longer enter Dunkard and other creeks. The solid waste is trucked to a nearby landfill that has multiple liners, leachate collection and leak detection.

The facility, landfill included, is designed to operate for 25 years. The plant employs 30.

This is not Consol's first RO plant. The company started operation in 2010 on a plant about half the size of this one, at a capacity of 1,600 gpm, at its Buchanan No. 1 mine in Virginia.

The benefit, and cost, of cleaner mining

Hibbs Run Reservoir, where the clean water goes, is a 30-acre lake, part of the 1,200-acre Dents Run Wildlife Management Area the state Division of Natural Resources obtained under long-term lease from Consol in 2010.

"It's one of our newest wildlife management areas," said DNR fisheries biologist Frank Jernejcic. "We're building a shooting range over there. And we'll manage the lake for bass and catfish and sunfish."

Dunkard Creek is recovering impressively.

"I get lots of reports on successful bass and muskie fishermen," Jernejcic said. He knew the creek well before the kill and monitored it closely during and after. The recovery has gone much faster than anticipated, he said. "I think most of us didn't have a clue to what had cumulatively happened to the streams."

DNR also has stocked the creek twice with fish inoculated with two species of mussels, but it takes years, if not decades, to evaluate the success of that.

Downstream from the Loveridge and Robinson Run mines, Buffalo Creek and tributaries of the West Fork River also are relieved of salty mine discharges.

Jernejcic observed that construction of the NWVWTP makes it possible to put a price on keeping streams clean in coal mining watersheds.

"The money they're spending indicates the legacy cost of treating mine water," he said.

That's $200 million in capital costs for the plant and pipeline and another $14 million each year to run it, an expenditure of $550 million over the plant's 25-year life. If the three mines produce each of those 25 years what they produced in 2012, that would come, without making any accounting adjustments, to $1.60 per ton of coal.