Bioremediation of phenols and polycyclic aromatic hydrocarbons in creosotecontaminated soil using ex-situ landtreatment

Soil from a former creosoting plant containing phenols and polycyclic aroma tic hydrocarbons, was remediated using an ex-situ landtreatment process. To tal 16 USEPA priority PAH and total phenol were reduced from 290 mg/kg and 40 mg/kg to <200 mg/kg and 2 mg/kg, respectively. The bioremediation proces s involved soil mixing, aeration, and slow release fertilizer addition. The indigenous populations of PAH and phenol utilizing populations of microorg anisms were shown to increase during the treatment process, indicating that biostimulation was effective. The most extensive degradation was apparent with the 2- and 3-ring PAH, with decreases of 97% and 82%, respectively. Th e higher molecular weight 3- and 4-ring PAH were degraded at slower rates, with reductions of 45% and 51%, respectively. Six-ring PAH were degraded th e least with average reductions of <35%. The residual concentrations of PAH and total phenol obtained in the study allowed the treated soil to be disp osed of as low level contaminated landfill. (C) 1999 Elsevier Science B.V. All rights reserved.