97100599 Bench-scale studies of reactor-based treatment of fuel-contaminated soils Truax. D. D. CI rrl.. Wusrc, Moncr~~??~cflr, lYY.5. 15. (516). 351-357. This study used contaminated soil made in the laboratory using No. 2 diesel fuel and sand to study the biological treatment of hazardous wastes in soil. ('ontamination levels studied were from 13.15 to 6675 mg (TPH) as derived tram No. 2 fuel oil per kg sand. Variation in mean cell age was obtained hctween hiol-eactors. with sufficient nutrients and oxygen made available to cnrurc the fuel oil organic\ were the only limit to microhlal growth. A thcclretical hiokinetic model was tormulated based on Monad's theory, of limiting \uh\tratc and continuous cultures. The results of thi\ investigation showed that c(mtinuous hioreactor treatment is a vinhle option in the treatment ot diesel-contaminnted undy soils. Removal efficiencies of up t(l YlI'; were :it~aincd at a Ioadlng of I.335 mg TPH!kg Liet sand. operated at a biological solid retention time (RSRT) of 60 days. Experiments also showed that TPH dc\orption and volatilization were not rate-limiting in the overall removal proces. Sand-to-moisture ratios in excess of 3: I were also shown to Irctard TPH rcmo\al rates very littlc. However. hiokinetic constant\ were It,und to vary t,>er a range of values. This was particularly true at varying diesel loading Icvel\ i%';rverthclesa. significant removal efficiency (up to Sh'( ) ~a\ n(>ted at the highest loading level tested. 6675 mp TPHikg wet Ullil. 97100600 Bioassay-based risk assessment of complex mixtures D<~nncl1!. K. ( and Huebnur, II. J.. /I s7;6l s/,ec 7izrh I'r,h/. lYY6. STP I20-I (Sunrrfuncl RI\I, A\essment in Soil Contamination Studies: Second C'dume): li7~11.5.