Biodegradation and leaching of polycyclic aromatic hydrocarbons in soil column

Polycyclic aromatic hydrocarbons are common ubiquitous compounds found in soils due to natural and anthropogenic productions, which are a threat to agricultural ecosystems. The present study aims to evaluate the efficiency of poly aromatic hydrocarbons removal in contaminated soil column. Also, prediction of the groundwater contamination as well as optimized biodegradation of these pollutants using the selective microbial consortium and various nutrients is among the crucial objectives of this study. For this purpose, four pilot bioreactors were used and filled with contaminated soil mixed with an indigenous microbial consortium and one of the following nutrients: (NH2),2CO (T1), (NH4)(2)SO4 (T2), NH4NO3 (T3). However, final treatment (T4) did not receive anything to estimate passive bioremediation. For each treatment, the bioremediation rates of poly aromatic hydrocarbons were estimated by measuring their concentration in effluences of the pilot and soil column with 1 m depth every 25 cm for 4-week intervals. The results showed that the highest rate of degradation of poly aromatic hydrocarbons was observed in the first two weeks in the depth of 0-25 cm soil column. The maximum percentage of biodegradation of total poly aromatic hydrocarbons after 4 weeks in the depth of 0-25 cm of the different treatments decreased in the order of (T2) 78.43% > (T3) 69.97% > (T1) 66.96% > (T4) 35.57%. After 4 weeks, the maximum percentage of total poly aromatic hydrocarbons in the drainage of soil columns was calculated as 1.56%.