ABSTRACT
Rapid industrialization and transport activities have increased the use of petroleum based fuels, to meet this demand extraction and refining of the crude oil has also been increased. Petroleum refining generates huge amount of wastewater containing oil and grease, salts and hydrocarbons, which has deleterious impact on the aquatic environment and their life forms. The oil droplets spread over the surface of water bodies and blocks the sunlight, the exchange of atmospheric gases that are essentially required by the life forms. For the treatment of petroleum wastewater, there are conventional physical, chemical and biological processes, which are applied in a series of steps; but not enough to provide the efficient treatment. Beside this, many advanced processes like photocatalytic oxidation, wet oxidation, catalytic vacuum distillation, fenton oxidation and ultrasonic degradation are also used, but their high building and operational cost have limited the scope for widespread adaptability.
Microalgal remediation can solve the problem of infective conventional methods and unaffordable advanced processes. Cyanobacterial mats are found to thrive in oil contaminated sites, but there are multiple opinions about the direct role of this microalgal community in oil degradation. It could be possible that hetertrophic bacteria are the prinicipal oil degraders in a cyanobacterial mats. However microalgae are able to metabolize simple hydrocarbons for their growth, and play an important role by supporting the bacterial growth by providing crucial oxygen for the bacterial respiration.
