Table 3.

Literature on petroleum waste water treatment, parameters and treatments

Pollutant type	Parameters	Treatment	References
Petroleum refinery effluent	COD, BOD, Oil and Grease	Identified photocatalytic degradation as efficient technique	Henrik Pederson et al. (2014)
Oil and greasy effluent	COD	Significant amount of COD (about 85%) reduction within 10 min	Correia T et al. (2015)
Heavy oil produced as effluent	BOD, COD, TKN, Oil	Surface flow constructed wetland can be removed	Correia T et al. (2015)
Highly saline waste water	NaCl, turbidity	RO is efficient for removing the salt concentration and organic matters	Mishra A et al. (2011)
Oily waste water	COD and oil Content	Photocatalytic decomposition of oily waste water by modification of catalyst activity	Henrik Pederson et al. (2014)