Raymond V. Lee, 37, of Grovetown, was shot at least once in the chest and taken to Medical College of Georgia Hospital, where he was pronounced dead, police said.
Police arrested Thomas Bradford, 43, of Hephzibah, a contracted truck driver who was hauling waste from the Reed Creek Water Pollution Control Plant in Martinez, Deputy Coroner Harriet Garrison said.
Bradford, a driver with Thomson-based Hudsons Grassing Co. Inc., was arrested about 2 p.m. and charged with murder.
Calls to the company were not answered Friday.
Bradford, who hauled sludge from wastewater treatment plants to facilities in Jefferson and Lincoln counties, was about to put a ripped tarp on his truck when someone told him to replace it, and an argument started, said County Commission Chairman Ron Cross.
Bradford and Lee might have had a disagreement in the past, Cross said.
When Bradford started to dump the waste, Lee told him to stop. Cross said Bradford initially tried to run over Lee with his truck.
Garrison said she was told Bradford went to his truck to get a gun after an altercation, and the two men struggled. According to witnesses, Bradford pushed Lee back and shot him, she said.
Bradford called 911 and told dispatchers he'd left his .380-caliber pistol on the running board of his truck, according to police radio reports. His call was disconnected, but he called back and said he was on his knees in the back parking lot.
Lee's body was taken to the GBI crime lab in Atlanta for an autopsy, Garrison said.
Lee had worked for the county for 14 years, Cross said. His middle child has a heart condition and recently was accepted for treatment at a Mayo Clinic, Cross said.
"It's just a bad situation," he said.
Cross said county officials are discussing setting up an education fund for Lee's children and would have more details next week.