SUMMARY OF SLUDGE REMOVAL PROJECT

BWX Technologies Inc.

September 2, 2008
to James River. The system, including the FEPs, is permitted by the Virginia Department

of Environmental Quality. The FEPs contain low level radioactive solids. For this

reason, they are incorporated into BWXLs Nuclear Regulatory Commission (NRC)

license that permits BWXT to process and possess radioactive materials.

A photograph of the FEPs is presented in Figure 1. FEP 1 (601) is triangular shaped and

FEP 2 (701) is rectangular shape and closer to the James River. FEP 1 was placed in

service in 1973 with a nominal capacity of 2,000,000 gallons. FEP 2 was placed inservice in 1979 with a nominal capacity of 1,900,000 gallons. Both FEPs were

constructed using existing on-site clay soil as a liner. The surface areas of FEP 1 and

FEP2 are approximately 1.6 and 1.4 acres.

The sludge in the FEPs originates from suspended solids carried over from the

neutralization ofradioactive and industrial wastewaters. The industrial wastewatersinclude effluent from a process that was considered by VDEQ to generate a listed F006

hazardous waste. BWXT successfully delisted the F006 filter cake solids in 2000. Thus,

Figure 1 BWXT’s Final Effluent Ponds

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from BWXT’s radioactive processing areas. The solids deposited in both ponds contain

low levels ofradioactivity. Under its NRC license, BWXT has analyzed the levels of

radioactivity in the FEP sludge several times. The sludge in the FEPs is regulated by the

NRC and is also considered to be a listed F006 hazardous waste. Upon removal from the

ponds, the sludge must be managed and regulated as a mixed waste. The FEP sludge

must be dewatered to meet the free water waste acceptance criteria at a licensed mixed

(radioactive/hazardous) waste disposal facility.

FEPs Sludge Removal Project

BWXT contracted with EnergySolutions to remove as much sludge as possible from the

FEPs under a turnkey project for the removal, shipping and disposal ofthe waste.EnergySolutions is a conglomerate of nuclear engineering, nuclear waste processing and

nuclear waste disposal organizations. EnergySolutions developed a sludge removal

approach for the FEPs that is presented in the following schematic.

Final Effluent Ponds

Solids

Schematic of FEP Sludge Removal Operation

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following its cable routes back and forth across the pond, the dredge operated around the

perimeter of the pond to ensure that any residue sludge in the pond was removed.

The dredge fluidized the sludge and pumped it to an agitation tank where chemicals wereadded to improve the filterability ofthe solids. A 213 cubic foot filter press was used to

remove the solids from the sludge slurry. The filtrate (water) was returned to the pond.

‘When the filter press reached its operating pressure it was “blown down” (excessive

water removed) and the resulting filter cake was dropped onto a moving conveyor belt.

The filter cake was deposited into a lift liner (240 cubic foot super-sack) that served as an

IP-2 shipping container. A small quantity of water adsorbent was added to each lift liner

to ensure that the packaged mixed waste met the free water criteria at the disposal site.

The filter cake generated in the dewatering process was on average approximately 25

percent ofthe volume of the sludge pumped to the filter press. The photographs ofthe

setup and final arrangement ofthe sludge dewatering system are presented in Figures 3

and 4.

Figure 2 Dredge located in Final Effluent Pond 1 (note front end “rototiller” device)

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The filled super-sacks were weighed and shipped in covered Gondola railcars to the

licensed mixed waste disposal facility. The sludge removal project generated a total of

450 super-sacks that contained 4,050 cubic yards (109,000 cubic feet) of filter cake, for a

-

Figure 3 Agitation Tank and Filter Press being Setup

Figure 4 Final System Setup and Operating arrangement

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EnergySolutions is confident that sludge in both FEPs was removed to the maximum

extent practicable. The volume offilter cake generated in the dewatering process is

approximately equivalent to 4,050 cubic yards (109,000 cubic feet) ofsludge removed

from the FEPs. In 2005, the total volume ofsludge residing in the ponds was estimated

at 13,200 cubic yards (356,400 cubic feet) based on detailed measurements of in situ

sludge thickness (BWXT, 2005). Therefore, only a small quantity ofthe sludge remains

in the FEPs.

Recently BWXT dropped the water level in FEP 1 in order to perform some maintenance

work on the inlet pipe to the pond. FEP 1 was relatively free ofsludge along its

perimeter and towards the center ofthe pond. However, adjacent to the inlet pipe, there

was a quantity ofsludge, estimated to be on the order of 2,000 cubic feet based on the

apparent area and thickness ofthe residual sludge. Assuming that an equivalent volume

ofsludge remains in FEP 2 (4,000 cubic feet for both FEPs), it is estimated that more

than 98% ofthe sludge has been removed from the ponds.

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