Abstract: The aim of the research was to demonstrate significant differences in the shares of phosphorus speciation forms after dosing sewage sludge with the Bacillus megaterium bacteria. The experiment was conducted throughout the period of seven days. Every day the following parameters were checked: the total count of the mesophilic bacteria, pH value as well as the share of particular speciation forms of phosphorus. On the basis of the research into the number of mesophilic bacteria one may suppose that the Bacillus megaterium bacteria colonized the hygienised sediment effectively and 24 hours after the dosing it was already possible to observe significant changes in the number of these bacteria. The fast colonization of the sediment by the bacteria is also connected with an intensive exudation of organic acids to the environment, which caused a 2.5 unit decrease of the pH value within 24 hours. The pH value did not change significantly in the last three days of the experiment but it was still low and amounted to about 3. This pH value indicates that the environment is strongly acidified, which in turn may influence the dissolving of the hard-to-access phosphorus forms, thus increasing the amount of mobile forms of this element. It was documented that the most significant changes in the shares of the speciation phosphorus forms were observed after 24-hour impact of the bacteria on the sewage sludge. In the following days the change was smaller. The presence of the bacteria caused the exudation of the mobile fraction on the first days of the experiment. The knowledge about the changes in the shares of the phosphorus forms, especially the bioavailable (mobile) ones, is important while using hygienised sediment cultured with microorganisms for environmental purposes.
Web of Science