83    DEVELOPMENT OF DESIGN CRITERIA FOR TREATMENT
OF METAL-CONTAINING WASTEWATERS
AT OAK RIDGE NATIONAL LABORATORY
George C. Patrick, Project Manager
Melvin R. Hockenbury, Vice-President
Engineering-Science, Inc.
Fairfax, Virginia 22030
Warren T. Thompson, Project Engineer
John M. Begavich, Development Engineer
Martin Marietta Energy Systems
Oak Ridge, Tennessee 37831
INTRODUCTION
A nonradiological wastewater treatment project was initiated to establish a treatment facility for
wastewaters generated at the Department of Energy's Oak Ridge National Laboratory (ORNL) in Oak
Ridge, Tennessee. The project was divided into four phases. This paper discusses only the work
associated with the first phase, wastewater characterization and treatability testing, which was conducted in 1985. The second phase which includes detailed design was performed in 1986. Construction
is expected to begin in late 1987 with start-up expected to begin in 1989. Specifically, this paper
discusses only the work associated with characterization and treatability testing of the wastewaters for
heavy metal removal. An overview of all the wastewater treatability tests including those which
evaluated air stripping and carbon adsorption for removal of organic compounds has been reported
by others.1
WASTEWATER CHARACTERISTICS
The wastewater treatment plant provides treatment of wastes from a variety of sources. These
sources include drainage from the various laboratories (chemical, physics, electronics, biological,
environmental and metallurgical); process wastewaters pretreated for radionuclides removal; boiler
blowdown from the stream plant; and aqueous streams from several radiochemical processing plants
and reactor operations. Analysis of the processes' wastewater showed that the heavy metals of concern
included cadmium, chromium, copper, lead, nickel, silver, zinc, and mercury. The source of these
metals was corrosion of the sewer pipes, metals used in the various laboratory reactions, and the
small-scale plating shops. Because large-scale plating or metal finishing is not performed at the Oak
Ridge National Laboratory, the metals concentration of wastewater was considered to be low.
Eight wastestreams were identified as contributing to the wastewater discharge at the Oak Ridge
National Laboratory. The characterization data of these wastewaters as well as the composite wastes-
tream are shown in Table 1.2 The values shown in Table I are maximum concentrations. In general,
the average concentrations were much lower. The composite sample had a concentration of less than
1 mg/L (1000 /ig/L) for each of the metals tested.
At the time that treatability tests were being conducted, the discharge requirements for the treatment system were not known. However, the discharge limitations for DOE's Y-12 facility located
adjacent to the Oak Ridge National Laboratory had recently been established and so these limitations
were used as a guideline for the treatability tests. The Y-12 limitations, as well as the primary drinking
water standards concentrations, are shown in Table II. The Y-12 permit limitations for all the metals
except iron, as shown in Table II, were between 0.1 to 1.0 mg/L.
The maximum metals concentrations of the ORNL composite were slightly higher than the Y-12
limitations. Since some of the wastestreams, specifically wastestream 3544, could probably be
bypassed around the metal treatment facility, the composite wastestream to be treated would have a
higher concentration for each metal. The 3544 wastestream could bypass the treatment facility
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