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.
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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. |
“I’ve been involved with this
project for 26 years and was here when we made uranium,” she says.
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.
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Photo: Department of Energy Office of Legacy Management
The site offers recreation for the community and
habitat feeding grounds for all classes of animals. |
LEED points were earned in areas
of sustainability, energy and atmosphere, and water efficiency. From the onset,
points were earned for reclaiming the brown site and transforming it into a
natural preserve. And rather than start from scratch, the Visitors
Center—designed by Megen Construction Co. and Glaserworks Architecture (www.bizjournals.com/cincinnati/related_content.html?topic=Megen%20Construction%20Co)—is
a refurbished storage building, one of the few buildings that didn’t require
demolition.
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.
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All Photos: Department of Energy Office of Legacy Management
The Visitors Center is a refurbished storage building. |
 |
Construction of biotreatment wetlands |
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Approximately 50 to 60 people have worked on the project, ranging from
construction workers to office staff, designers, and health and safety staff. |
Flow from the septic system is
controlled through a series of manholes. First, the equalization manhole, and
then, the distribution manhole, where water is directed north to two parallel
subsurface flow wetlands.
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.”
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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. |
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By utilizing native plants, less irrigation water is needed, and it provides
natural habitat for animals and insects. |
The Big Picture
Although the biotreatment wetlands
aren’t hydraulically connected to other wetlands on the site, they fit in well
and enhance the natural atmosphere that is the Fernald Preserve.
“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.