Adsorption is one of the most common techniques for removing
contaminants from wastewater. It has been shown that
adsorption using activated carbon is able to cope with a wide
range of contaminants due to its large surface area characteristic
[36]. Therefore, any integration with adsorption unit processes can
be a great hybrid system to improve the wastewater quality. As
presented in Table 2, adsorption–coagulation–dissolved air flotation
hybrid is able to get rid of high percentage of oil and grease
(91.6 to 94.4%) in the hydrocarbon reservoir, known as produced
water. The schematic diagram of adsorption–coagulation–dissolved
air flotation hybrid is as shown in Fig. 3a.