Gannett Co. won U.S. antitrust approval for its $1.5 billion purchase of Dallas-based Belo Corp. and its 20 television stations, including WFAA/Channel 8, under a settlement with the Justice Department that requires the sale of a St. Louis television station.The station, CBS affiliate KMOV-TV, was among six Belo stations that Gannett already planned to sell to Sander Media for $101 million. But Gannett, which owns KSDK-TV in St. Louis, had agreed to align advertising sales incentives with Sander, which would drive up rates, the department said.Gannett said Monday that Sander has agreed to divest KMOV-TV next year. It will be sold to a buyer approved by the U.S., the department said in a statement. “The full divestiture required by the department will ensure that KMOV-TV will remain a vigorous competitor in St. Louis,” said Bill Baer, head of the department’s antitrust division. Gannett, based in McLean, Va., publishes USA Today and 81 other daily newspapers, and owns and operates 23 broadcast television stations nationwide. Belo, the oldest continuously operating business in Texas, spun off its newspaper division, including its flagship, The Dallas Morning News, into a company called A.H. Belo Corp. in 2008.In addition to WFAA, Belo operates KHOU in Houston, KVUE in Austin and KENS in San Antonio.