Environmental Characterization of Metal Finishing Sludges

Application of Leaching Tests for the Assessment of Available Heavy Metals from Domestic and Industrial Sludges

“…Only in the case of Cr, the values of Samples IS1 and IS2 are clearly higher than to that found in the domestic sludges and the values of Ni in these samples are similar to that obtained in Samples DS1 and DS2. The elevated Cr content found in the industrial sludges could be perfectly attributed to the use of Cr(VI) for chromation operations in the coating finishing industry, reduced to Cr(III) in the wastewater treatment plant [36]. On the other hand, it is important to stress that the total metal contents found in all the analyzed domestic sludges as well as the Samples IS1 and IS2, except Cr, does not APPLICATION OF LEACHING TESTS 725 present a pollution problem in agricultural uses, according to Portuguese environmental regulation [10].…”