Columbia County is exploring cleanup options to stem the flow of contaminated groundwater migrating from its aging Baker Place landfill near Grovetown.

When the landfill opened in 1982, its first two 30-acre waste burial cells did not have protective liners because laws requiring them were not adopted until 1990 and did not take effect until 1993.

Consequently, groundwater flowing beneath those areas has become contaminated with methane -- "landfill gas" -- and various materials contained in liquid leachate that settles to the bottom of landfill garbage as it decomposes.

"What we will be doing is addressing contamination that's been discovered at that facility from that unlined portion of the landfill," said Don Bartles, the county's solid waste manager.

A later waste cell, which opened in the mid-1990s and closed in 2006 after it was filled, includes a protective liner and a leachate collection system.

A network of monitoring wells indicates a small plume of contamination that has moved southwest, off the landfill property, and onto a portion of Interstate 20. The affected area is about 56 feet below the water table.

Cleanup options include groundwater extraction, in which wells are drilled into the contaminated area.

Water pumped out would be discharged into the newer, lined portion of the landfill, which has a liquid recovery system.

That water is confined in a storage tank, then pumped to a county wastewater plant for final processing into clean water.

Pumping from the affected portion of the aquifer slows or halts the spread of the contamination, Mr. Bartles said.

Any cleanup plan must also be approved by the county's Public Works Committee and Georgia's Environmental Protection Division.

The county also is required to monitor the area for 30 years after the landfill is closed.

The unlined cells were closed in 1991 and 1995, respectively, and capped with a protective layer of dirt. The county's last cell, a 15-acre lined site, was closed in 2006.

The county will finance any necessary cleanup with a reserve fund accumulated over the years by proceeds of the small per-ton surcharge on waste buried at Baker Place. The county also can apply for funds from a state-managed trust fund created for landfill remediation.

The county's reserve fund had about $15 million when the landfill closed in 2006, Mr. Bartles said. About $3.5 million will have been spent by December in closure and capping activities, and the 30-year monitoring program is expected to cost $6 million to $7 million.

Remediation for the two unlined landfill cells has cost about $150,000 so far, and additional measures, Mr. Bartles estimated, would be in the $30,000 to $50,000 range.

Reach Rob Pavey at (706) 868-1222, ext. 119 or rob.pavey@augustachronicle.com.