Biological methods of petroleum-contaminated wastewater purification

This review describes basic methods for purification of oil-contaminated wastewaters. Biotechno-logical methods were considered as suitable for oil-contaminated wastewater treatment. These approaches use bioreactors with immobilized monocultures of hydrocarbon-oxidizing microorganisms or their associations. In this review, the advantages of fluidized-bed bioreactors over other types of reactors are demonstrated. A fluidized-bed reactor provides (1) an increase in the retention time of carrier-immobilized cells in the reactor vessel, (2) even distribution of contaminated wastewaters across the irrigated area of the carrier with immobilized bacterial cells, and (3) using of small-size bioreactors without additional aeration systems.