Rocky Flats Plant,
Waste Treatment Facility
HAER No. CO-83-AI (Rocky Flats Plant, Building 774)
Rocky Flats Environmental Technology Site, Highway 93, Golden, Jefferson
County, Colorado. Building 774 is located in the northern portion of the protected area.
The west side of the building is adjacent to the east side of Building 771C.
This building is a secondary contributor to the Rocky Flats Plant
historic district, associated with the U.S. strategy of nuclear military
deterrence during the Cold War, a strategy considered of major importance in preventing
Soviet nuclear attack. Constructed in 1953, Building 774 was the original liquid process
waste water treatment facility at the Rocky Flats Plant. Building 774 was designed
to treat the liquid process wastes generated in Building 771. As the plant expanded to
accommodate increased production of nuclear weapon triggers, Building 774 began processing wastes for additional plant operations and buildings.
Building 774 was originally a two-story rectangular structure designed
to treat liquid process waste. The original portion of the building is constructed of
poured-in-place concrete. By 1989, seven additions had been made to the building,
resulting in a multi-level structure varying from one to four stories in height. The
additions are constructed of block wall, reinforced concrete, metal-on-metal framing, and
transite. As a result of the additions, floor space increased to 25,000 square feet. The
facility is built on a steeply sloping site. The first floor on the north side is 7.5 feet below-grade, and the fourth floor on the south side is 4 feet above-grade.
Building 774 was designed to treat the liquid process wastes generated in
Building 771. As the plant expanded to accommodate increased production of nuclear weapon
triggers, Building 774 began processing radioactive acidic
wastes; caustic, aqueous, and organic wastes; waste oils; and non-radioactive waste
photographic solutions. Buildings 111, 112, 130, 371, T371J, 441, 444, 460, 551, 559, 664,
707, 750, 771, 776, 777, 881, and 991 generated one or more waste streams that were
processed in Building 774. In 1971, the waste treatment operations in this building were
enclosed to provide containment of radioactive airborne particles.
The goal of the waste treatment process, which occurred in Building 774, was to reduce
liquid radioactive wastes and convert them into a form suitable for transport off site for
storage and disposal. In general, wastes were either piped directly into Building 774, or
transferred in drums, containers, or other types of packaging. The waste entered a series
of interconnected tanks designed to treat acidic, caustic, and radioactive wastes, and
separate relatively low-level radioactive effluent from contaminated solids or sludges.
Each of the four processes used in the building were tailored to meet certain
characteristics of the waste. The waste may have passed through one or more of these
processes before entry into the next stage of the operation. These first stage processes
- Neutralization and filtration of acidic wastes containing large quantities of metal
ions or chloride ions. The main purpose of this process was to remove the large quantities
of metal hydroxide solids from the waste stream, as these solids hampered the
decontamination ability of the succeeding flocculation and clarification processes.
- Batch neutralization, precipitation, and filtration of acidic wastes containing only
small quantities of metal ions or basic wastes containing large quantities of undissolved
- Continuous radioactive decontamination of neutral and caustic wastes.
- Solidification of aqueous wastes containing complexing agents, certain radioactive
isotopes, or hazardous chemicals that were undesirable in the regular waste system. These
wastes were mixed with an absorbent material and Portland cement in barrels for disposal.
This process was eventually replaced by the organic and sludge immobilization system. The
organic and sludge immobilization system accepted waste oils from any building at the
plant that contained transuranic material and converted the liquid waste into solid waste.
The second stage of the decontamination process included two separate radioactive waste
decontamination processes. The benefit of segregating the wastes was better utilization of
the waste storage ponds based on whether or not the wastes met standards for radioactive
and chemical contamination. The two processes were:
- Batch precipitation to remove radioactive materials from wastes containing both
radioactive and chemical contaminants in excess of standards. After the radioactive
material was separated from the waste, if the remaining liquid met the on-site storage
guidelines for radioactivity, it was transferred to asphalt-lined evaporation ponds,
otherwise it was reprocessed to reduce contaminant levels.
- Continuous precipitation to remove radioactive materials from wastes meeting the
standards for chemical but not radioactive contaminants. After the radioactive material
was separated from the waste, if the remaining liquid met drinking water standards, it was
transferred to an evaporation pond, otherwise it was reprocessed to reduce contaminant
The slurry from both processes was held in a slurry tank until it was processed by
vacuum filtration to separate the solids from the liquid. The separated solids were mixed
with a solidifying agent, and packaged for shipment and long-term storage as
transuranic-mixed (hazardous and radioactive) waste.
Recovery of silver from photographic solution also took place in Building 774. Waste
photographic solution flowed through silver recovery units where silver was plated onto an
electrically charged metal plate and recovered as silver ingots for resale.
The role of Building 774 diminished with the inauguration of the new process waste
treatment facility in Building 374. Building 774 continued to process all contaminated
organic wastes that could not be incinerated and the liquid process wastes generated in
United States Department of Energy. Site Safety Analysis Report,
Notebook 7-Security, by EG&G Rocky Flats, Inc.
Rocky Flats Repository. Golden,
United States Department of Energy. Mission Transition Program Management
Plan, Site Support Facilities
Element. Appendix A-1, A-2, A-3, A-5 Revision 7, A-4
Revision 4 (1992), by EG&G. Rocky Flats Plant Repository,
Golden, Colorado, 1992.
United States Department of Energy. Draft Rocky Flats Plant Plutonium Recovery
Reference Process, by
Rocky Flats, Inc., Golden, Colorado, 1991.
United States Department of Energy. Rocky Flats Plant, Interim Safety Analysis
Report (1989), by Rockwell International Energy Systems Group. Rocky Flats
Repository. Golden, Colorado, 1989.
United States Department of Energy. Final Cultural Resources Survey Report (1995), by Science Applications International Corporation. Rocky Flats Repository. Golden,
Weaver, Jack, employed at the plant since 1961 by the site contractor. Personal
communication, August 1997.
D. Jayne Aaron, Environmental Designer, engineering-environmental
Management, Inc. (e2M), 1997. Judith Berryman, Ph.D., Archaeologist, e2M,
Index to Photographs
Located adjacent to Building 771C, in the northern portion of the protected area, Golden Vicinity, Jefferson County, Colorado.
Photograph CO-83-AI-1 was taken by Rockwell International on August 23, 1977.
CO-83-AI-1 – View of the interior of Building 774, the original liquid process wastewater treatment facility. The photograph shows storage tanks and associated plutonium-contaminated solutions. The glove box is used by operators to manually operate pumps and valves that require periodic adjustment. Other valves in the room were infrequently adjusted, and are sealed in plastic wrap.