Browsing by Author "Koolivand, Ali"
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Item Open Access Bioremediation of petroleum hydrocarbons by vermicomposting process bioaugmentated with indigenous bacterial consortium isolated from petroleum oily sludge(Elsevier, 2020-04-25) Koolivand, Ali; Saeedi, Reza; Coulon, Frederic; Kumar, Vinod; Villaseñor, José; Asghari, Fatemeh; Hesampoor, FaezehFinding a sound ecological-based approach for the removal of petroleum hydrocarbons (PHCs) from petroleum oily sludge (POS) generated in oil refinery plants is still a challenge. This study investigated the removal of total petroleum hydrocarbons (TPHs) using bioaugmentated composting (BC) by hydrocarbon-degrading bacteria (HDB) and vermicomposting (VC) by Eisenia fetida, individually and in combination (BCVC). After isolating two native bacterial strains from POS prepared from an oil refinery plant in Iran, the degradation capability of their consortium was initially assessed in mineral Bushnell-Haas medium (MBHM). Then, the biodegradation rates of POS in the BC, VC, and BCVC treatments containing different concentrations of TPHs (5, 10, and 20 g/kg) were determined by measuring TPHs before and after the biodegradation. The results showed that the consortium degraded 20–62% of TPHs contents of Kerosene (1–5%) in the MBHM after 7 days. After 12 weeks, the TPHs removal percentages in the BC, VC, and BCVC treatments were respectively found to be 81–83, 31–49, and 85–91 indicating the synergistic effect of bacteria and worms in bioremediation of POS. The PHCs biodegradation in the BC, VC, and BCVC experiments was fitted to 1st order model kinetics. The results of toxicity tests indicated that the values of the no observed lethal concentration (NOLC) and median lethal concentration (LC50) of TPHs were 2–5 and 14.64 g/kg, respectively after 28 days of earthworm exposure. Morphological impairments such as swelling, coiling, and curling were observed when TPHs concentration was even lower than NOLC. The study verified the effectiveness of vermicomposting bioaugmentated with the indigenous bacterial consortium for POS bioremediation.Item Open Access Effect of competition between petroleum-degrading bacteria and indigenous compost microorganisms on the efficiency of petroleum sludge bioremediation: field application of mineral-based culture in the composting process(Elsevier, 2020-01-06) Abtahi, Hamid; Parhamfar, Milad; Saeedi, Reza; Villaseñor, José; Sartaj, Majid; Kumar, Vinod; Coulon, Frederic; Parhamfar, Maryam; Didehdar, Mojtaba; Seifi, Hamed; Koolivand, AliThe effect of competition between isolated petroleum-degrading bacteria (PDB) and indigenous compost microorganisms (ICM) on the efficiency of composting process in bioremediation of petroleum waste sludge (PWS) was investigated. After isolating two native PDB (Acinetobacter radioresistens strain KA5 and Enterobacter hormaechei strain KA6) from PWS, their ability for growth and crude oil degradation was examined in the mineral-based culture (MBC). Then, the PDB isolate were inoculated into the composting experiments and operated for 12 weeks. The results showed that the PDB degraded 21.65–68.73% of crude oil (1–5%) in the MBC after 7 days. The PDB removed 84.30% of total petroleum hydrocarbon (TPHs) in the composting bioreactor containing the initial TPH level of 20 g kg−1. Removal of petroleum hydrocarbons (PHCs) in the composting experiments proceeded according to the first-order kinetics. The computed values of degradation rate constants and half-lives showed a better performance of the PDB than ICM for TPHs removal. This finding suggests that simultaneous application of the PDB and ICM in the composting reactors resulted in a decline in the effectiveness of the PDB which is due to competition between them. The study also verified that the capability of PDB in degrading PHCs can be successfully scaled-up from MBC to composting process.Item Open Access The effect of petroleum hydrocarbons concentration on competition between oil-degrading bacteria and indigenous compost microorganisms in petroleum sludge bioremediation(Elsevier, 2022-01-17) Koolivand, Ali; Abtahi, Hamid; Parhamfar, Maryam; Saeedi, Reza; Coulon, Frederic; Kumar, Vinod; Villaseñor, José; Sartaj, Majid; Najarian, Niloofar; Shahsavari, Maedeh; Seyedmoradi, Paria; Rahimi, Leila; Bagheri, FatemehThe influence of the concentration of total petroleum hydrocarbons (TPHs) on competition between isolated oil-degrading bacteria (ODB) and finished compost microorganisms (FCM) was investigated in composting bioreactors over 12 weeks period. First, the batch tests were performed in Bushnell–Haas medium (BHM) to evaluate the biodegradation activities of six native ODB isolated from petroleum sludge (PS). Then, the ODB were added to the composting bioreactors containing 10 and 30 g/kg of TPHs. Based on the BHM results, the highest degradation efficiency of crude oil (1%–3% concentration) were determined to be 72%–75% at pH 7 after 7 days. In the composting bioreactors containing only the ODB, TPHs removal rates were 86%–92% after 12 weeks. Although the lower degradation efficiency of TPHs (73%–89%) in the bioreactors containing both the FCM and ODB indicated a slight competition between them, the ODB were still effective in the presence of the FCM especially at greater concentrations of TPHs. Despite the fact that the addition of finished compost (FC) to the PS changed the microbial composition in the composting bioreactors; the microbial populations exhibited little variation during the process. This study indicated that the isolated ODB, alone or in the presence of the FCM, effectively degraded the PS in the composting process.