Ahmad, Jamil, Muhammad Umar, Shujaat karim, Muhammad amaduddin, Kareem Akhtar, and Feroz Shah. 2018. “Effect of Coagulation Flocculation and Sand & Gravel Filtration on the Quality of Car Wash Waste Water”. Journal of the Pakistan Institute of Chemical Engineers 45 (2). http://piche.org.pk/journal/index.php/jpiche/article/view/370.