SHAMOKIN DAM -- Sunbury Generation LLC is the only facility in the Valley treating gas-well wastewater from Marcellus Shale drilling.

The plant received authorization by the state Department of Environmental Protection in November to treat up to 80,000 gallons a day.

However, according to Ed Griegel, of Sunbury Generation, it is receiving significantly less than that amount.

"It's just not available," he said. "It depends on the market."

Much of the water the facility treats comes from drilling locations in Tioga County and other Northern Tier counties.

The facility collects a fee for wastewater disposal from the drilling companies, he said.

A regular industrial wastewater facility treats 2 million gallons a day, according to Bob Hawley, manager of the Water Management Program at DEP, in Williamsport.

According to DEP, Marcellus Shale is a rock formation that underlies much of Pennsylvania and portions of New York and West Virginia at a depth of 5,000 to 8,000 feet, and is believed to hold trillions of cubic feet of natural gas.

Through a hydrofracturing process, exploration companies blast millions of gallons of chemically treated water into the Marcellus Shale well under high pressure, Hawley said. The water will include sand, which fractures the rock. The process leaves sand particles behind in order to prop open fractures in the rock, allowing the gas to flow better.

Approximately 30 to 50 percent of the water pumped into the well is pumped back out, Hawley said.

Wastewater treatment plants must contact DEP for a permit to treat certain chemicals, and then are required to maintain the standards provided, said Griegel, of Sunbury Generation.

Earlier this month, U.S. Sen. Robert Casey Jr. introduced legislation that would close a Bush administration loophole that made gas drilling the only industry not required to disclose exactly what chemicals are used in the fracking process. Casey noted that some chemicals known to have been used in fracking include diesel fuel, benzene, industrial solvents and other carcinogens and endocrine disrupters.

Once the wastewater from the drilling sites is hauled in by trucks, Sunbury Generation is required to perform a pretreatment for pH and metals, oil and grease. This is completed in a separate concrete basin. The treated water is then added to the existing industrial waste facility, and then sent out through the existing outfall to the Susquehanna River, Hawley said.

As a power plant, Sunbury Generation has extra capacity, and is able to run that water in and blend it with the wastewater facility there.

Through the treatment process, the chemicals are collected into a solid state. They currently are being held on site at Sunbury Generation, and will soon be disposed of into permitted landfills.