BIOLOGICAL TREATMENT OF A SOIL CONTAMINATED WITH DIESEL FUEL USING PERIODICALLY OPERATED SLURRY AND SOLID-PHASE REACTORS

A silty clay loam contaminated with diesel fuel was treated in the lab oratory using periodically operated slurry and solid phase bioreactors . Soil Slurry-Sequencing Batch Reactors (SS-SBRs) were operated with a 40% solids concentrations (w/v) to determine the effect of hydraulic residence time and volumetric replacement strategy on performance. Sol id Phase-Sequencing Batch Reactors (SP-SBRs) were operated with the sa me silty clay loam artificially contaminated with diesel fuel. Differe nt periodic aeration strategies were investigated in the SP-SBRs in an attempt to minimize volatile losses without sacrificing overall-remov al efficiency. Results showed that a day 10 HRT in the SS-SBRs was opt imal for the soil tested. The rate and extent of diesel fuel removal w as increased by providing a higher concentration of diesel fuel at the beginning of the SBR cycle, indicating that removal rates are not zer o-order. The findings also showed that a properly operated periodic ve nting strategy produced high overall removal efficiencies with conside rably less volatilization than continuous aeration. Copyright (C) 1996 IAWQ.