Sewage sludge is a very complex system, with solids and water. It is generated as waste from wastewater treatment. Sewage sludge is used to fertilize agricultural and forest areas and to rehabilitate devastated areas. It is a good organic fertilizer because it contains significant amounts of nutrients beneficial for plant development and humus-forming substances. The composition of sludge from municipal wastewater treatment plants is similar to soil organic matter, therefore it can be used to improve the physicochemical properties of soil, increasing its sorption capacity. Research material was collected in the Swietokrzyskie and Mazowieckie Voivodships. Sewage sludge was collected from the wastewater treatment plants in Sitkowka Nowiny (Sitkowka) and Kunow, as well as high-quality agricultural soil from Opatowiec and sandy-clay soil from Jastrzebie. Research was carried out on the sorption of heavy metals (Cd, Cr, Cu, Pb, Ni, Zn) by mixtures of sewage sludge with soil. The calculations were made for the concentrations of heavy metals in sewage sludge, soil, and sewage sludge–soil mixtures. The geoaccumulation index (Igeo) and the risk assessment code (RAC) were calculated. Increased sorption capacity was demonstrated in samples with a predominance of sewage sludge. It was shown that heavy metals from sewage sludge, after mixing with soil, changed their form from immobile to mobile.

No abstract

The paper presents the results of research on the content of selected heavy metals (Cu, Pb, Zn, Ni) depending on pH, organic carbon content and soil sorption in the direct location of busy streets around the campus of the Kielce University of Technology. Based on the conducted studies of the sequential fractionation of metals by the BCR method was found that the highest content of nickel fraction FI (exchangeable) was 142.75 mg/kg. However, the total nickel concentration in all research areas exceeded the value specified in the Journal of Laws approx. 2 times. The lowest content from the analyzed metals in the surface layer of soil was found for zinc, the content of which was 1.5% in relation to the standard. The average percentage share of the analyzed metals in the separated fractions, in relation to the total content, was in decreasing series for Ni: FIII > FI> FII> FIV; for Pb: FII > FI > FIV > FIII; for Cu: FII > FI > FIII > FIV and for Zn: FII > FIII > FI > FIV. The studied soils are characterized by a varied granulometric composition of sand fraction, from very thick (1000 μm-2000 μm) to very fine 2 μm-50 μm). Statistical calculations showed that the pH, Corg content and sorptivity of the studied soil correlate with each other.

No abstract

No abstract