Rhizoremediation of petroleum hydrocarbon-contaminated soils: Improvement opportunities and field applications

The remediation of petroleum hydrocarbon-contaminated soils has remained a challenging issue for environmental scientists and engineers. Within the scope of bioremediation; rhizoremediation has emerged as the most suitable method for petroleum-impacted soils. It can be promoted by the proper selection of suitable plant-microbe combinations and its overall efficiency can be enhanced by adding suitable soil amendments. This review article summarizes the available knowledge on rhizoremediation with respect to plant selection, inoculation with specific microbial strains (hydrocarbon-degrading as well as plant growth-promoting microbes) and a variety of soil amendments for enhancing the remediation efficiency. A large set of organic and inorganic soil amendments has been presented for the discussion on potential increase of rhizospheric effects. Finally, we discussed a unique multi-process phytoremediation system (MPPS) for the remediation of petroleum-polluted soils along with its field applications.