The investigation of nutrient addition impact on bioremediation capability of gasoil by Alcaligenes faecalis

Oil and Gas well excavation, frequent extraction and its pumping to refineries and translocation of oil products to consuming sites, cause ecosystem contamination, especially soil contamination. This issue make inevitable the application of efficient methods which are either environmental friendly or appropriate for any sites. The bioremediation technology which is biological remediation of these contaminants, is much more efficient and safe than other clean-up technologies. Therefore, the aim of this study was to investigate hydrocarbon (Gasoil) removal rate from soil by Alcaligenes faecalis with the addition of nutrient in a bioremediation experiment. This study was carried out as factorial in a completely randomized design. The factors were two levels of bacteria (with inoculation by Alcaligenes faecalis and without inoculation) plus two levels of nutrient (with the addition of nutrients and without nutrients addition). There were three replication for each treatment. Therefor the experiment was establish with 12 experimental unites in plastic containers which had soils with 4% of Gasoil. The experiment was carried out in laboratory conditions (addition of nutrients, moisture as 70%-80% FC and daily aeration) for 40 days. After this time the biological removal rate of Gasoil in soils were measured using EPA 413.1 and EPA 9071 methods. Results showed that regarding mentioned condition, Alcaligenes faecalis could remediate in average 78% of Gasoil contamination. Furtheremore, the addition of nutrients could increase the efficiency of bioremediation of Gasoil by 11% in comparison with condition no nutrient addition. Key words: Alcaligenes faecalis, Bioremediation, Gasoil, Petroleum contaminant.