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Photo: Department of Energy Office of Legacy Management

Looking at the site, it’s not obvious what took place there years ago. In May 1951, ground was broken on a 1,050-acre site in the southwest corner of Ohio, and construction began on the Feed Materials Protection Center. Over the next four decades, operations at the site would produce almost 500 million pounds of uranium product that would be used in the production of nuclear weapons.

During the years it operated, contamination spread across the site, and by 1986 the plant was on the National Priorities List. In 1989, operations at the facility ceased, and by 1991 remedial efforts had begun. The damage was extensive—over 400 acres of soil were contaminated, and a 225-acre contaminant plume existed beneath the site. Waste was left in place and included more than 1 million tons of low-level radioactive waste, 6.6 million cubic feet of containerized low-level waste, nearly 175,000 gallons of low-level liquid waste, and 31 million pounds of nuclear product. The site also included 224 process-related administrative structures.

Cleaning up the site was one of the largest remediation projects in the nation’s history. Contaminated groundwater continues to be remediated through an onsite pump-and-treat system. Waste and contaminated soil, and other media, were taken offsite for disposal. The majority of the buildings were decontaminated and decommissioned. An onsite disposal facility remains on the site, but is not accessible to the public.

Jane Powell is the Fernald Preserve site manager with the US Department of Energy (DOE), Office of Legacy Management and has a long history with the site.

Photo: Department of Energy Office of Legacy Management The Fernald Preserve Visitors Center received a LEED platinum certification in September 2008. It was the first platinum rating in Ohio and only the second for DOE.

The Office of Legacy Management was established by the DOE, to provide long-term and sustainable solutions for sites originally used during the Cold War era. The office took on responsibility for the Fernald site once environmental remediation was deemed complete in 2006. But that doesn’t mean the site that Legacy Management was left to work with was a pristine pallet. Excavations were left unfilled, and poor quality soil was left in place.

“We were left with a lot of deep excavations,” says John Homer, Fernald Preserve ecological restoration group lead with S.M. Stoller Corp. “There was a big production area with a lot of foundations; once they were pulled out and disposed of offsite, we were left with severe topography. But we took advantage of it and used it to create a series of wetlands and open water, surrounded by prairie.”

“What’s been done here verges on a miracle,” says Powell. “It was the combined effort of the DOE, contractors, the community, and regulators.”

The miracle Powell refers to is the effort involved, from the community through the government, to make Fernald Preserve what it is today—a connected series of wooded lots, prairie, wetlands, open water, and savanna. Rather than provide ingredients for the country’s nuclear arsenal, the site now offers passive and active recreation for the community, along with habitat and feeding grounds for all classes of animals from mute swans and salamanders to beavers and toads. Over three miles of open and wooded paths—with names like Shingle Oak Trail—wind through a portion of the site, allowing visitors to enjoy the flora and fauna Fernald Preserve has to offer.

And one onsite building not only tells the story of the preserve, but also offers an example in sustainable design and operation.

The Visitors Center
In the northwestern part of the Fernald Preserve sits the Visitors Center, but it’s more than just a building. The 10,000-square-foot center provides visitors with a bit of history, and, according to Powell, “it’s a story worth telling.”

Students and staff from the University of Cincinnati, OH, worked on the various multimedia displays. But they didn’t go it alone; designers attended community stakeholder meetings to make sure the citizen’s needs were met. Displays in the Visitors Center are not typical for a nature preserve. They include an impressive video of one of the structures imploding during demolition. Interactive multimedia is used to tell the story as it progresses from when Native American’s lived on the land to the settlers and farmers who arrived later, and then, finally, the uranium operations.

Duck and Cover, a civil defense film shown routinely to schoolchildren in the 1950s, rolls in what’s called the Cold War room. News reports of the contamination from the1980s are presented along with models, showing the site as it transforms into its current state.

But there’s another story to tell—it’s about the how the Visitors Center was designed and constructed, and the role it plays in creating more sustainable buildings. In September 2008, the Fernald Preserve Visitors Center received Leadership in Energy and Environmental Design (LEED) platinum certification from the United States Green Building Council (USGBC). Originally designed for Gold certification, the center garnered more points than anticipated, elevating it to platinum status. It was the first platinum rating in Ohio and only the second
for DOE.

Photo: Department of Energy Office of Legacy Management The site offers recreation for the community and habitat feeding grounds for all classes of animals.

Geothermal heating and cooling uses a nearby lake with water that ranges from 50°F to 60°F year-round. During the summer, the heat exchanger helps cool the building, and in the winter, it heats it. Other amenities that increased the LEED score include bike racks and showers for cyclists and preferred parking for low-emitting and fuel-efficient cars.

The center scored a perfect five out of five points in the water efficiency category. A portion of the score addressed the use of native and drought-resistant plants. By utilizing native plants, less irrigation water is needed, and it provides natural habitat for animals and insects. A rain garden is used to collect water from the parking lot, keeping it from entering the storm sewer. And collected rain is used to irrigate native plants, when needed, and provides water for animals.

Plumbing fixtures that reduce water use by 41% were installed. Bathroom fixtures include low-flow, dual-flush toilets. When only liquids need to be flushed, 1.1 gallons of water are used. Solids use 1.6 gallons of water. The urinals chosen use only 0.5 gallons of water per flush.

The final touch in the water efficiency category is the biotreatment wetlands used to handle wastewater produced in the Visitors Center. Because the treatment process utilizes plants and microorganisms in concert with the environment and keeps all processed wastewater onsite, a perfect score in water efficiency was achieved. And because of local regulations, the biotreatment system was designed without the benefit of reduced flows.

“Gains in water efficiency were not factored into the basis of design,” says Homer. “The design flow was based on published values from the Ohio Administrative Code. Sizing of the system was driven by the potential use of the meeting room. The meeting room can hold 200 people, so the system had to be sized to meet that capacity.”

No corners were cut; the treatment system was sized for full occupancy.

The Biotreatment Wetlands
Initially, the biotreatment wetlands seem analogous to a typical septic system, but there are differences that go beyond replacing the standard infiltration gallery with wetlands. “The wastewater treatment system for the Visitors Center is different from a standard septic system in a couple ways,” says Homer. “Secondary and tertiary treatment is provided by a two-stage system, where wastewater is pumped from the holding tanks to a lined subsurface flow wetland. Effluent from the subsurface flow wetland is either recirculated through the wetland or released to a surface flow wetland. The surface flow wetland is designed as a zero-discharge system, with water lost via evapotranspiration.”

The key components of the treatment system break down as follows:

The Septic System. The septic system is comprised of two 2,000-gallon septic tanks set up in series and located just west of the Visitors Center. Wastewater gravity flows from the Visitors Center to the septic tanks where primary settling takes place.

All Photos: Department of Energy Office of Legacy Management The Visitors Center is a refurbished storage building.

Construction of biotreatment wetlands

Approximately 50 to 60 people have worked on the project, ranging from construction workers to office staff, designers, and health and safety staff.

Subsurface Flow Wetland System. The total subsurface treatment area is 5,580 square feet. The subsurface wetlands are designated as secondary treatment, but achieve tertiary treatment standards.

Treatment in the lined subsurface flow wetland system is designed to meet Ohio Administrative Code which requires the following parameters to be treated: biological oxygen demand, total suspended solids (TSS), total Kjehldahl nitrogen (which include ammonia, nitrates, and nitrites), total phosphorus and pathogens, or bacteria and viruses. From the surface flow wetlands, treated water gravity flows to a recirculation manhole equipped with a pump. Flow is either pumped back to the influent of the subsurface wetland system, to keep water from stagnating during times of low flow, or into the surface wetlands system.

Surface Flow Wetland System. As water enters the 1.53-acre wetlands, it is equally dispersed throughout gravel bed where TSS is filtered out. Treatment relies on a series of natural processes that take place between the gravel bed buried below the surface and the vegetation planted at ground level. Microorganisms within the media, and attached to the root systems, break down organic matter in the wastewater. Plants such as green bulrush, duck potato, blue flag iris, river bulrush, and prairie cordgrass pull water out of the subsurface water through transpiration. This slightly reduces the volume of water and can increase nutrient concentrations in the sediment.

Oxygen concentrations within the wetlands also affect treatment. In the shallower portions of the wetlands, oxygen from the surface assists in nitrification. Deeper portions of the wetlands that do not have access to air encourage denitrification. Ultimately, nitrates are broken down into nitrogen and nitrous oxide gas, and are volatilized through the surface.

Because pathogens, such as fecal coliform, will naturally die off, the wetlands system is designed with adequate residence time. Phosphorus is removed through adsorption to the gravel mediate or adsorption by the wetland plants.

The surface flow wetland is the final stage in the treatment system. Because the treatment system is designed for zero-discharge, all water must be lost either to infiltration, evaporation, or evapotranspiration. The surface wetland system was constructed out of an existing pond. To ensure there was adequate volume to support needed plant species and maintain zero-discharge, the original pond was regraded and expanded. Berms were also incorporated into the footprint of the wetland to avoid short-circuiting of the water as it flows through. The wetland was sized to retain flow from November through March, when transpiration, evapotranspiration, and infiltration are minimal.

A slight disadvantage to biotreatment wetlands is the time required to establish startup and adequate treatment levels. Unlike manmade equipment, plants must have time to establish themselves and become attuned to their surroundings. Part of that process is ensuring flows to all parts of the system are controlled.

For the system at Fernald Preserve, startup included opening the septic system to accept flow from the Visitor Center. To make certain water wasn’t released until treatment was assured, the valve between the septic tank and flow equalization was locked shut.

Potable water was then used to test the equalization manhole, located between the septic tanks and the subsurface wetland. Flow from one unit to the next is controlled by a series of four floats. Starting at the lowest elevation, the first is a low float that switches the pump off, the second float turns on one pump, and the third turns on the second pump. The fourth and highest float trips an emergency alarm. An alternating relay was installed to ensure pumps are used equally to avoid damage from over- or under-use of any one pump.

Once controls for the flow equalization system were set, water was pumped through the flow distribution manhole into the subsurface wetlands. Downstream of the wetlands, plates were adjusted to maintain adequate depth upstream. Water that flowed to the recirculation manhole was then pumped back to the equalization manhole, just downstream of the septic tank.

This was the final step in starting up the system. When complete, the valves were opened, and the system deemed operational. Weekly inspections included evaluation of vegetation and collection of samples for analysis of carbonaceous biochemical oxygen demand. With the system up-and-running, only routine operation and maintenance is required.

“The surface flow wetland is designed as a zero-discharge system, so no routine effluent from the system is anticipated,” says Homer. “There is a discharge pipe, for system maintenance, and an emergency overflow spillway that empty into a series of wetlands and ponds. These basins eventually drain into a large excavation that provides passive groundwater recharge. As far as managing the system, valves and control structures are opened and closed manually. Pumps are controlled from panels in the field.”

Photos: Department of Energy Office of Legacy Management Plants like green bulrush, duck potato, blue flag iris, river bulrush, and prairie cordgrass pull water out of the subsurface water through transpiration.

By utilizing native plants, less irrigation water is needed, and it provides natural habitat for animals and insects.

“It’s an undeveloped park,” says Powell. “The deer and the turkey, balance with the community needs. Everything is incorporated into the same mosaic.”

An old aerial photo was used along with a land survey dating back to the 1800s that included native plant species. This information helped guide the team, both in how to restore areas and what plants to choose. All in all, approximately 50 to 60 people have worked on the project ranging from construction workers to office staff, designers, and health and safety staff.

“Everybody who worked onsite took a lot of pride in the project,” says Powell. “People who knew the site from the 50s, 60s, and 70s even come back to visit. People wanted it to be eco-friendly.”

And it is that. All in all, the cost to remediate the site was $4.4 billion. The cost for environmental restoration was $14 million. According to DOE reports, closure of the site came in 12 years earlier than expected and $8 billion less than original estimates.

In an October 2008 speech at the site, Acting Deputy Secretary of the DOE summed up Fernald’s transformation and emphasized importance of the LEED certification earned by the Visitors Center with these words:

“…The educational opportunities this site and Visitors Center affords point us toward a greater understanding of the world around us. But there is yet another way in which this Visitors Center points us toward the future, a future that will depend upon increased energy efficiency and enhanced environmental responsibility across all sectors as we seek to secure our energy future. And so today, as we remember and seek to preserve the many contributions Fernald has made to our national security, we also celebrate Fernald’s future—the future of America—as we forge ahead to achieve energy security in an environmentally responsible way.”

The Visitors Center at the Fernald Preserve illustrates the potential for sustainability.