Effects of different kinds of sewage sludge amendment on urban lawn grasses

The paper presents the results of research on the use of sewage sludge from the municipal sewage treatment plant in Białystok for fertilization of urban lawns. To fertilize the ground two types of deposits were used: stabilized sludge after the dewatering process in the press and granular sludge after drying in the sludge dryer. Two doses of sludge were used – 5 and 10 kg/m². Effective microorganisms (EM) were added to the test plots. Both doses of the applied sewage sludge contributed significantly to the growth of grass biomass. Aboveground biomass of the plants was significantly correlated with the concentration of Cd, Cu, Pb and Zn in the surface layer of the soil. The addition of EM to soil containing the dewatered sludge from the press reduced significantly the content of heavy metals in the soil, as opposed to the sludge in a form of granules with addition of EM, which contributed to the increase of their concentration in the soil.