Removal of detergents in car wash wastewater by sub-surface flow constructed wetland

Abstract

Suspended substances in car washes can often be easily removed by physicochemical processes. The main problem is to remove dissolved substances such as detergents from the water. In this study, a biodegradable substance Sodium Lauryl Sulfate (SLS) was removed from the car wash wastewater by the use of Phragmites australis in the subsurface constructed wetland. For this study, 4 plexiglass reactors having an effective volume of 10.8 L with the dimensions of 15cm×45cm×20 cm were used. The experiments were conducted with vegetation which was called SCW and without vegetation which was named control group (CG), as two groups. A serial connection of two reactors was performed for each group. Up to 90% detergent removal was observed with the vegetation in the SCW with a loading rate of 75 L/(m2.d) The effluents quality showed that the treated water can be reused carwash or irrigation for landscaping.