Membrane bioreactors for the treatment of oily wastewater: pros and cons

Urbanization and industrialization creates waste water, in which, now a days, oily wastewater is a serious concern due to its very complex management options. Moreover, the problem is not local as the oil on waste water spreads around, so internationally several laws have been imposed on the regulation to manage the oily wastewater originating from different sectors. Oily wastewater contains toxic substances such as phenols, petroleum hydrocarbons, polyaromatic hydrocarbons, which are inhibitory to plant and animal growth, equally, mutagenic and carcinogenic to humans. So, treatment of this particular oily wastewater is a concern at local and international levels. Existing treatment technologies of oily wastewater like gravity separation, dissolved air flotation, evaporation, and incineration have several limitations. As an alternative to these physicochemical treatment processes, biological treatment offers better promise toward this challenge but as oily wastewater becomes highly saline and contains several toxic chemicals, it hinders the organism’s growth and so the treatment process as well. Biological treatment coupled with membrane separation has been found to effectively address this problem since it retains high biomass and leaves a small footprint. Although like other methods, membrane bioreactor also has some limitations. This chapter has critically evaluated the MBR technologies for case sensitive effectiveness for oily wastewater treatment.