FEATURES OF THE ACCUMULATION OF METAL IONS IN SLUDGES OF THE BIOENERGY COMPLEX

A study of the accumulation of metal ions in the sludge of the bioenergy complex after burning the plant's raw materials was carried out. The value of the content of toxic metals (cadmium, lead, and mercury) is less than an order of magnitude than the MPC for soils. The presence of a complex of trace elements, iron, calcium, magnesium, and sodium in sludge makes them attractive for use as raw materials for production of organic-mineral fertilizers for the cultivation of a sufficiently wide range of agricultural and ornamental crops. It was studied that distribution of heavy metals in sludge of the filtration fields in different depths : 1 – from the surface (1–5 cm), 2 – from the middle (~500 cm) and 3 – from a depth > 1500 cm. The distribution of metal's ions accumulation established that the maximum content of cadmium and nickel observed in the surface layer of silt, lead in the middle layer, and manganese in the deep (more than 1500 m) layer. Such distribution of heavy me­tals shows, that the maximum concentration of cadmium and lead takes place in the surface layer of silt, lead in the middle layer , and manganese in the deep (more than 1500 m) layer. Thus, the deep layer is the safest to use as a raw material in production of fertilizers. But the presence of cadmium and lead, which have cumulative properties, in all layers of sludge is a risk factor for using sludge as fertilizers for crops that will be used for food purposes but can be use for growing technical crops and ornamental plants. Also, the presence of aluminum and titanium in the composition of the sludge requires a more detailed study. The final decision is possible only after conducting field tests, with subsequent analytical control of products and soil after harvesting.