Kl. Ogden et al., REMEDIATION OF LOW-LEVEL MIXED WASTE - CELLULOSE-BASED MATERIALS AND PLUTONIUM, Journal of hazardous materials, 51(1-3), 1996, pp. 115-130
Low-level mixed radioactive wastes containing cellulose-based material
s and plutonium have been generated during various nuclear processing
activities. Biological digestion of the organic- or cellulose- based m
aterial was examined as an environmentally acceptable and effective me
thod of treatment for these and other similar wastes. Cellulase enzyme
was used to initiate biodegradation prior to 90% destruction of the c
ellulose material by a sewage sludge consortium. Plutonium did not sig
nificantly effect the biodegradation. Bench-scale experimental data we
re used to design a batch treatment system. A cost and sensitivity ana
lysis was performed to determine the optimal reactor size, materials o
f construction and media type. The sensitivity analysis indicated that
while a 12-month treatment scenario using a carbon steel ball mill, s
ludge digester and vacuum thickener was the least expensive scenario e
valuated on a levelized cost basis ($800 per ton of waste degraded per
month), the 12-month scenario using stainless steel construction and
the alternative dewatering system offered the most cost-effective trea
tment alternative and better corrosion resistance (levelized cost of $
1130 per ton per month). The dewatering system consisting of a disk ce
ntrifuge and sludge dryer is capable of doubling the sludge solids con
tent and produce an overall waste reduction of 67%. The proposed waste
treatment system offers a cost savings of up to 31% compared to conve
ntional disposal practices.