CHARACTERIZATION OF THE LIQUID-PHASE OF SEWAGE-SLUDGE - EFFECTS ON COPPER(II) ADSORPTION BY SOIL

A study has been carried out in order to investigate both the role of organic compounds present in sludges and the effect of their decomposi tion on the adsorption process of copper(II) following application of sludges to soils. Strong interactions occur between soils and water so luble organic compounds of sewage sludges applied to agricultural soil , These interactions influence the adsorption process of the metals; t his is promoted by the change in the nature of organic matter that occ urs during the decomposition process. The results obtained with soil s amples treated by us with the liquid phase of a sewage sludge (LPS), a nd with soil portions collected in a neighbouring zone treated 10 year s ago with sewage sludges have been compared. It appears clear that th e behaviour of the soil treated with LPS allows prediction of the adso rption pattern of the sludge-amended soil towards heavy metals.