Wpływ procesu stabilizacji na całkowitą zawartość metali śladowych i ich frakcje w komunalnych osadach ściekowych

The article presents the results of sewage sludge investigations, coming from two water treatment plants purifying similar household sewage with 75-95% efficiency. Despite different technology of sludge processing in each plant, physico-chemical parameters of sludge were similar. Total content of heavy metals in Bytom-Miechowice did not exceed standard, maximum values reguired for sludge being used in agriculture. Sludge from Dąbrowa Górnicza-Strzemiszyce did not meet reqirements because of excessive amount of Pb, Cd, Zn. Seqential trace element extraction revealed, that in the two fractions of the greatest importance for the environment, i.e. exchangeable (I) and bound with carbonates (II), percentage of metals in sludge from both plants was relatively small and comparable. For both investigated plants metals were bound mostly with organic fraction (IV). The greatest amount of metals in every fraction were found in sludge coming from anaerobic fermentation process in Dąbrowa Górnicza-Strzemieszyce.