OMAHA, Neb. (AP) — A federal appeals court has affirmed a $2.3 million penalty against a company that operated a rendering plant in Lexington and violated the federal Clean Water Act and the Nebraska Environmental Protection Act.

STABL Inc. had appealed the penalty, ordered by a federal judge last year. Federal officials said STABL had violated terms of its wastewater discharge limits hundreds of times between August 2006 and May 2010, resulting in an economic benefit to the company of more than $1.1 million. The pollutants included ammonia, oil and grease.

In its appeal, STABL argued — among other things — that discharge monitoring reports used against it were unreliable and should not have been allowed into evidence. On Thursday, the 8th U.S. Circuit Court of Appeals rejected that and other arguments by STABL.