Thus, it is necessary to pre-treat wastewater from metal and automobile industry by precipitation of its high content of heavy metals, in particular Cr, Ni, Cu and Zn before subjection to secondary biological treatments.
Thus, it is necessary to pre-treat wastewater frommetal and automobile industry by precipitation of its high contentof heavy metals, in particular Cr, Ni, Cu and Zn before subjection tosecondary biological treatments.