A Fillmore County farmer who sought to build the county’s largest animal feedlot has withdrawn his permit application in the face of sustained local opposition, marking the end of the road for the proposed Catalpa Ag hog farm.

State pollution officials said Monday that Al Hein informed them of his decision via e-mail, and that it terminates his application.

Hein, the majority holder in Catalpa Ag, wanted to build a piglet operation with nearly 5,000 pigs on his farm near Mabel, Minn., in southeastern Minnesota. The operation would have been managed by Iowa-based Waukon Feed Ranch.

The feedlot ignited unusual local alarm, drawing large crowds at two informational meetings held by the Minnesota Pollution Control Agency (MPCA) and a record number of comments during the agency’s public-comment period. Area residents and others expressed concern that the 7.3 million gallons of liquid manure the pigs would produce each year would threaten their groundwater. They pressed the MPCA to require a full environmental review of the proposal and said that southeastern Minnesota, with its porous karst geography, was the wrong place for the large operation.

Manure is a source of nitrate, a form of chemical salt that can cause health problems in drinking water, and an estimated 15 percent of the private wells in Fillmore County exceed the safe drinking water standard for nitrate.

In December, the MPCA took the rare step of denying Hein’s application for a general permit, citing concerns that the karst geology was too sensitive to contamination.

Hein applied again, this time for an individual permit, a customized document that would have likely included additional protections for water resources. Most of the state’s 1,300 state-permitted feedlots are covered under general permits, according to the MPCA.

Hein did not respond Monday to a request for comment, and MPCA officials declined to discuss what prompted his decision.

Groups opposed to so-called factory farming welcomed the news.

“This is truly a win for the common good,” said Sonja Trom Eayrs, an activist with Dodge County Concerned Citizens, which opposes large animal feedlots. “It’s nice to see the citizen ‘Davids’ defeat the corporate big ag ‘Goliaths.’ ”

Bobby King of the Land Stewardship Project, a nonprofit advocacy group that opposes big feedlots, said he thinks the MPCA would have issued the permit but for the vocal pushback. “It was the many hundreds of rural residents and farmers that came together to stand up for their rural community who essentially did the MPCA’s job of protecting Minnesota’s air and water,” King said.

Dayna Burtness, a hog farmer and one of the leaders of a local citizen’s group called Responsible Agriculture in Karst Country, agreed. The victory is bittersweet, she said, explaining that she feels relief but remains frustrated that ordinary citizens must work so hard to get more rigorous oversight of concentrated animal feeding operations (CAFO).

“As Iowa becomes more and more saturated with hog CAFOs, they’re going to keep looking to spread into southeastern Minnesota,” Burtness said. “This isn’t the last hog operation we’re going to face.”