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The aim of study was to determine the impact of three different biogas fermentation residues on some chemical and biochemical characteristics in sandy soil. The laboratory experiment was carried out on loamy sand. Residues were added to soil samples in the forms of pulp, drought, and granulate at dosages of 10, 50, and 100 g·kg-1. The reference was the soil sample without residues. On day 28, the content of macroelements and heavy metals was determined. In addition, on days 1, 7, 14, 28, and 56, the content of biomass and the activities of some hydrolases and oxidoreductases were assayed. Results showed that the application of all fermentation residues caused an increase in most of the chemical parameters. The highest impact on pH and the content of Ctot, Ntot, Stot, K, and P was observed in the soil treated with granulate, whereas the increase in the content of heavy metals was the highest after the drought application. The effect of biogas fermentation residues on all hydrolases and o-diphenol oxidase activities was mostly significant, but depended on the kind of residues and the day of experiment. Biomass content and the activity of dehydrogenase were increased in the whole experiment.

Survival of microorganisms in soils from treatment facility and landfill of wooden railway sleepers contaminated with creosote oil as well as in two types of soils with different content of organic carbon, treated with creosote oil vapors, was assessed. Microbiological assays including determination of: the biomass of living microorganisms method and the number of proteolytic, lipolytic and amylolytic microorganisms were carried out under laboratory conditions. Chromatography analysis of the soil extract from railway sleepers treatment facility was performed using GC/MS. The highest biomass and the number of tested microorganisms were determined in soils from wooden railway sleepers landfill, while the lowest in soil from the railway sleepers treatment facility. Vapors of creosote oil, regardless of the soil type, significantly increased only the number of lipolytic bacteria.