Source: EM Update | Vol. 12, Issue 7; Contributor: Anne Smith | February 18, 2020 


Crews at the headworks site of the Outfall 200 Mercury Treatment Facility are excavating for the construction of foundations.

 Oak Ridge workers building the Outfall 200 Mercury Treatment Facility recently achieved a safety milestone: zero lost workday cases and zero recordable injuries since mobilizing for the project six months ago.

The facility is vital to help fulfill EM’s regulatory commitments to reduce mercury levels in the East Fork Poplar Creek and enable large-scale cleanup and demolition to begin at the Y-12 National Security Complex. Outfall 200 is where the headwaters originate for the Upper East Fork Poplar Creek at Y-12.

Employees with Oak Ridge contractor APTIM – North Wind Construction (ANW) contribute to the project’s safety culture in a variety of ways. They conduct daily safety briefings, which provide opportunities for employee discussion and feedback; participate in continuous site- and task-specific training; implement appropriate controls from hazard recognition and analysis; and conduct regular site safety inspections.

The project also benefits from the Outfall 200 Health and Safety Committee, which convenes at least monthly. The group is comprised of representatives from EM, ANW management, and the project.


The site of the treatment plant for the Outfall 200 Mercury Treatment Facility, where workers are preparing to install concrete.

The treatment facility includes a headworks facility and a treatment plant connected by a pipeline nearly a mile long. The headworks facility will capture creek flow on the west end of Y-12, store excess stormwater collected during large rainfalls, remove grit, and pump water through the pipeline to the treatment plant on the east side of Y-12. The treated water will then flow into the creek.

Crews at the headworks site are currently excavating for the construcion of foundations. They are installing a wall designed to stabilize and support the surrounding soil that will be 110 feet long and 35 feet high when complete. At the treatment plant site, crews are installing materials and structures needed to pour concrete.

When the treatment facility is operational, it will limit and control potential mercury releases as crews take down massive Cold War buildings and address soils — activities that may disrupt the mercury-contaminated area on the west end of Y-12. The facility is designed to treat up to 3,000 gallons of water per minute and includes a 2-million-gallon storage tank to collect stormwater.