Adsorption and biodegradation of high explosives on granular activated carbon

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20014774

Morley, M C; Shammas, S; Speitel, Jr, G E

Adsorption to granular activated carbon (GAC) is an effective method for removing high explosives (HE) compounds from water, but no permanent treatment is achieved. An off-line bioregeneration system, which combines adsorption and biodegradation, is being developed to reduce GAC usage rates and destroy RDX and HMX. Desorption is often the limiting mass transfer mechanism in bioregeneration systems; thus, two cosolvents, four surfactants, and two cyclodextrins were considered for improving desorption of RDX and HMX. In batch experiments, about 3% of the adsorbed RDX was desorbed over 11 days using buggered water as the desorption fluid. In comparison, about 96% of the RDX was extracted from the GAC by acetonitrile. Ethanol and methanol were both effective in desorbing RDX and HMX. Sodium dodecyl sulfate (SDS), an anionic surfactant, desorbed 56.4% of the RDX at a concentration of 500 mg SDS/L. Cyclodextrins were marginally more effective than water. Continuous operation of a sequencing batch reactor (SBR) has effectively treated both contaminants. In an SBR that was operated with 4-day cycles for 72 days, mixed cultures consistently reduced RDX concentrations from 1 mg/L to non-detectable levels and HMX from 0.6 mg/L to 0.4 mg/L over each cycle. When removal from groundwater by adsorption is combined with enhanced desorption and subsequent biological treatment, the overall process is expected to effectively increase the GAC service life and provide a permanent treatment method for RDX and HMX.

• Research Organization: Univ. of Texas, Austin, TX (US)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: FC04-95AL85832
• OSTI ID: 20014774
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
54 ENVIRONMENTAL SCIENCES
ACETONITRILE
ACTIVATED CARBON
ADSORPTION
BIODEGRADATION
CHEMICAL EXPLOSIVES
DESORPTION
REGENERATION
REMEDIAL ACTION
SOILS
SURFACTANTS