Assessment of Bioaugmentation and Biostimulation Efficiencies for Petroleum Contaminated Sediments

 The effectiveness of hydrocarbon bioremediation strategies approaches is depending on various issues such as type and volume of pollution, nutrient accessibility in the target ecosystem, time, biodiversity of microorganisms, pollutant bioavailability and many others. In the present research, laboratory studies were carried out on the bioremediation of coastal sediment samples artificially contaminated with weathered crude oil. The efficiency of natural attenuation, bioaugmentation and biostimulation for removal of Total Petroleum hydrocarbons (TPH) were compared in 90 days experiments. Three oil concentrations of 3, 30, 60 g oil/kg soil were studied to investigate the effect of oil concentration on the bioremediation process. The average degradation, in biostimulation tests were 52.11, 58.36 and 43.02% whereas in bioaugmentation tests were 73.89, 73.76 and 58.31% for 3, 30 and 60 g oil respectively. The results indicated that excessive crude oil (more than 30 g/kg in this case) is not suitable for bioremediation presumably duo to inhibitory or toxicity to the microorganisms. By supplementation of acclimatized microorganism as well as nitrogen and phosphorus, a satisfactory amount of biodegradation is reachable in two months.