MIDDLETOWN, IN -- Biodiesel producer E-Biofuels has agreed to pay an $18,000 fine for two discharges into city sewers that interfered with the operation of the town's wastewater treatment plant, the Star Press reported.

A discharge of waste product into sanitary sewers occurred on July 9, 2007, and a discharge of biodiesel byproduct occurred during the weekend of May 9-12 of this year, according to the Indiana Department of Environmental Management.

"It was a fat-like grease that floated on top [of the wastewater at the treatment plant]," Tim Mundell, a Middletown council member, told the newspaper, referring to the discharge this year. "They [E-Biofuels] came down and paid for it to be skimmed off. They cleaned up our sewage treatment plant for us."

According to IDEM spokeswoman Amy Hartsock, the discharge "falls under the category of fat, oil or grease."

"Workers in the treatment facility observed in the primary clarifier a yellow residue that smelled fatty, like an animal smell," Hartsock said. "Some soapy residue was observed as well as the yellow residue. Thick, soap-like residue was noted clinging to vegetation at the outfall as well."

Glycerin, a byproduct of biodiesel facilities, is classified by law as a "fat, oil or grease" pollutant, Hartsock told the Star Press.

Biodiesel is made through a chemical process called transesterification, in which glycerin is separated from fat or vegetable oil. The process leaves behind two products: methyl esters (the chemical name for biodiesel) and glycerin (a byproduct usually sold to be used in soaps and other products).

"We had an incident in May when an employee mistakenly put approximately 100 gallons of soap into our sanitary sewer outlet instead of the appropriate holding tank, which led to this incident at our Middletown facility," said Chad Ducey of E-Biofuel. "One of our employees improperly placed a discharge hose from a vessel we use to water wash the biodiesel for a short amount of time into a drain to the sanitary sewer."

"We worked very quickly to minimize the impact of that incident to the [treatment plant] in Middletown," he said.

Ducey added that the company will continue to train employees on proper procedures. In addition, E-Biofuels has taken further steps to prevent similar problems from occurring in the future. "Along with meeting these requirements, we have also installed a sanitary sewer interceptor as a precautionary measure to further prevent any discharges from reaching the sanitary sewer system in Middletown," Ducey said.