MILLSBORO, Del.- The Delaware Department of Natural Resources and Environmental Control is directing Mountaire Farms to clean up an accidental wastewater release at its poultry processing facility near Millsboro.

A mechanical failure caused between 750,000 and 1 million gallons of partially treated wastewater to be discharged on Mountaire's property early Wednesday morning. The release was contained on site, with no discharge to the nearby Swan Creek, DNREC said.

According to Mountaire, the portion of the wastewater system that caused the release went into operation in late January, and it is designed to reduce nutrient levels in the wastewater that is sprayed on the land where the release occurred.

Clean-up efforts began as soon as Mountaire's alarm system notified workers of the malfunction and was expected to be complete as of Thursday evening. The recycling operation was expected to resume Thursday morning, Mountaire said.

DNREC said it would continue to investigate the incident while monitoring the company’s cleanup.

Last year, Mountaire agreed to pay a $420,000 civil penalty and offer an alternative water supply to nearby residents whose wells have been contaminated with high levels of nitrates. In a consent decree with state officials, the company also agreed to address problems with the wastewater treatment system at its Millsboro area plant.

Mountaire is also being sued by area residents complaining of water pollution.