Comparative remediation rate of biostimulation, bioaugmentation, and phytoremediation in hydrocarbon contaminants

The environmental pollution caused by crude oil spillage has been recently turned into a critical challenge that requires a comprehensive plan to effectively reduce the contaminants in a short period. Bioremediation technologies as an efficient, cost-effective, and eco-friendly method are a good substitution for physiochemical techniques, except for requiring an approximately long time for remediation which limits their application on large scales. To increase the rate of biodegradation, some methods have been proposed to promote the living conditions of the indigenous/exogenous microorganisms. This review tries to address the recent works on the most common biodegradation technologies including biostimulation, bioaugmentation, phytoremediation, and immobilization by definition of biodegradation improvement per day parameter as an indication of degradation improvement per a specified time. The comparison analysis shows the highest degradation rate of immobilization, although it suffers from the high cost of immobilization carriers. In contrast, the phytoremediation process exhibits the lowest degradation rate, which could be accelerated by microorganism inoculation. Adjusting the optimum ratio of soil nutrients by the addition of waste materials could be also one of the cost-effective ways of hydrocarbon degradation. Considering the petroleum-contaminated soils as a serious threat to human, animal, and plant life, reaching maximum remediation during a short time is desired, if the remediation method is technically and economically appropriate. The results of this study will pave a way to roughly estimate the most efficient method for maximum biodegradation in a short time.