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 laboratory 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. Solid Phase-Sequencing Batch Reactors (SP-SBRs) were operated with the same silty clay loam artificially contaminated with diesel fuel. Different periodic aeration strategies were investigated in the SP-SBRs in an attempt to minimize volatile losses without sacrificing overall-removal efficiency. Results showed that a day 10 HRT in the SS-SBRs was optimal for the soil tested. The rate and extent of diesel fuel removal was increased by providing a higher concentration of diesel fuel at the beginning of the SBR cycle, indicating that removal rates are not zero-order. The findings also showed that a properly operated periodic venting strategy produced high overall removal efficiencies with considerably less volatilization than continuous aeration. Copyright (C) 1996 IAWQ.