Treatability of metal finishing wastewater in Alexandria

ABSTRACT

This work aimed to study the characteristics and treatability of wastes representing the different types of metal finishing in Alexandria. Ten samples from each of the studied three metal finishing types were collected over one year. The samples were subjected to complete physical and chemical analysis. Two treatment approaches were applied [precipitation and adsorption]. The results of analysis indicated that the wastewater effluent violated the decree 44/2000. PH, conductivity, dissolved solids, total phosphate and some heavy metals were examples of the parameters violated the decree limits. The results of the precipitation treatment using different doses of lime indicated that with increasing pH, the reduction of all the measured parameters increased. PH of 9.5 [8.5 in case of anodizing waste] gave the best reduction of all the measured parameters and became complied with the decree limits. The results of activated carbon adsorption treatment in pH range 4.5-7.5 indicated that adsorption efficiency increased with pH increase. PH of 7.5 showed the best reduction of all the measured parameters and were complied with the decree limits