Tribar Manufacturing will resume sending its wastewater to the Wixom Wastewater Treatment Plant, the city announced Thursday, more than a month after the company released toxic hexavalent chromium into the sewer system that feeds into the plant. 

Wixom granted Tribar with conditional approval to continue discharging to the plant after the city, company and regulatory agencies developed a series of improvements designed to prevent similar releases. 

"The process improvements that are required at Tribar Plant #5 address the non-compliance issues which led to the Cease and Desist order issued on August 1st and both the City and Tribar will actively monitor for ongoing compliance," Wixom Mayor Steve Brown said in a press release. "Given these process improvements, we have issued a conditional approval for discharge to the Wixom Wastewater Treatment Plant for Tribar Plant #5."

The Thursday announcement ended a month-long cease and desist order Wixom had issued because of the hexavalent chromium release. 

"We want to thank the city for their close collaboration through this process and are pleased we have been able to resume normal operations," Tribar said in a statement. "As we have said from the beginning, we take our commitment to the community and the environment seriously. We are thankful our systems worked as intended. However, we are continuing to improve our internal systems and controls so something like this cannot happen in the future."

Tribar released 3,892 pounds of hexavalent chromium into the sewer system on July 29, the Michigan Department of Environment, Great Lakes and Energy determined in an investigation. Hexavalent chromium is a carcinogen and dangerous to human health and the environment.

A Tribar employee overrode waste treatment alarms 460 times, EGLE said in a violation notice. The company also failed to notify the state immediately after discovering the pollution discharge, EGLE said. 

State environment and health officials assumed the pollution reached Norton Creek, which feeds into the Huron River, but further analysis showed most of it was contained at the manufacturing plant and in sludge at the wastewater treatment plant. What wasn't captured largely broke down into trivalent chromium, a less toxic substance. 

Wixom issued Tribar the cease and desist order, which prohibited the company from discharging waste to the city's wastewater treatment plant, on Aug. 1, the day Tribar warned city and state officials of the release.

Tribar, Wixom and regulators developed this series of improvements for Tribar operations before Wixom agreed to end the order: