Evaluation of Petroleum-Degrading Bacteria in phytoremediation of soil contaminated with petroleum(Case study: Soils surrounding Tehran Oil Refinery)

The present research aims to evaluate simultaneous application of petroleum-degrading bacteria and phytoremediation of petroleum-polluted soils under greenhouse conditions. For this purpose, rangeland species Agropyron cristatum and Achillea millefolium in treatments with and without inoculation with bacteria B. megaterium and B. subtilis for petroleum contaminated soil surrounding Tehran refinery with pollution 5.3 and 7 wt% were applied. TPH variation was monitored with and without inoculation of bacteria for rangeland species. The results showed the best removal efficiency of TPHs for Agropyron cristatum at the end of growth period in presence of Bacillus megaterium and Bacillus subtilis treatment in 5.3 wt% pollution level was 72.18 and 64.08% respectively and as for Achillea millefolium it was 60.59 and 58.12% respectively. Also percentage of EC reduction Agropyron cristatum at the end of growth period in presence of Bacillus megaterium and Bacillus subtilis treatment in 5.3 wt% pollution level was 42.37% and 39.27% respectively and as for Achillea millefolium it was 33.41 and 31.48% respectively. the highest PH variations was occurred in presence of bacteria so that it was recorded in Bacillus subtilis treatment for Agropyron cristatum about 7.25%. Finally it can be noted that Agropyron cristatum and Achillea millefolium cultivated in TPH contaminated soil are resistant to oil pollution and reduced some oil pollution, however Agropyron cristatum was superior in removing petroleum pollution.