SOLAR DETOXIFICATION OF FUEL-CONTAMINATED GROUNDWATER USING FIXED-BEDPHOTOCATALYSTS

A field test of a solar photocatalytic process for detoxification of w ater was conducted at Tyndall Air Force Base, Florida, where benzene, toluene, ethylbenzene, and xylene (BTEX) compounds were found in the f uel-contaminated groundwater. Platinized titanium dioxide supported on silica gel is packed in tubular photoreactors and used for single-pas s operations. Catalyst fouling, destruction inhibition, and water pret reatment are investigated in addition to BTEX destruction. Ionic speci es were found to be primarily responsible for photocatalyst fouling an d destruction inhibition. A simple pretreatment unit was developed for removing turbidity, adding oxidant, and ionic species. By using pretr eatment, the reactor system operated efficiently, and no loss in catal yst photoactivity was found during the month-long test. On a rainy day , BTEX compounds of a total influent concentration of more than 2 mg/L were destroyed within 6.5 minutes of empty-bed contact time. Test res ults with various flow rates, reactor diameters, influent concentratio ns, solar irradiances, and weather conditions confirm the application potential of the process.