JESSUP, Ga. (From the Florida Times-Union) -- The Georgia Environmental Protection Division issued a permit to allow Rayonier Advanced Materials to continue discharging treated wastewater into the Altamaha River at its Jesup plant but with tighter limits on pollutants.

The EPD sent out a letter in late December informing those who commented during the permitting process that the resulting document protected the environment and that the permit had been issued.

Atlanta lawyer Hutton Brown, who represented the Altamaha Riverkeeper in the permitting process, said he was told Monday the permit had been issued and hasn't had time to study it fully.

"From what I've seen, our concerns haven't been addressed," he said.

The big sticking point -- and most visible -- objection from environmental groups was the dark black discharge that stained the river for miles downstream along with tighter limits on conventional pollutants.

Rayonier spokesman Russell Schweiss said the company had spent a lot of money clearing up the discharge water.

"We spent $70 million in the past eight years to upgrade the facility to reduce the color," Schweiss said. "That's not a small capital investment. We've got [only] two mills."

The substance responsible for the stain is lignin, Schweiss said.

Lignin is an organic polymer that helps form the cell walls of plants. Lignin holds the cellulose together and gives trees and other plants their rigidity. In breaking down trees to the pure cellulose that Rayonier Advanced Materials converts to clear plastic, the lignin had formerly been discarded into the wastewater, but, Schweiss said, that process has been changed.

"Where we've concentrated our efforts is to capture that color," before it becomes wastewater, Schweiss said.

The formerly discharged lignin is now captured and used as fuel to help power the plant, he said.

The company is working with employees to ensure that lignin is captured and not discharged, Schweiss said.

The clear cellulose is used as computer and TV screens and competes with petroleum-based plastic in the market place, he said.

"To our customers, lignin is a contaminant," because it would make the products less transparent, he said.

The new permit imposes new monitoring and testing requirements and changes the reporting from an annual average to a monthly average, which will prevent spikes in color during times of low flow in Georgia's largest river, Schweiss said.

Brown said he will fully study the permits and then consult with the Riverkeeper on filing an appeal.

But Brown said it is obvious the permit limits don't adequately address the color and odor of the discharge and that the permit "kicks the can down the road."

The EPD also required Rayonier Advanced Materials to pay for a study. While some may see that as an onerous requirement, Brown said it's unnecessary because the problems have been known for years.

"We just don't think we need a study. This plant is 60 years old. It's a little late in the day for a study," he said.