Method of reclamation of contaminated soils of ash dump

Abstract

The utility model relates to the field of agriculture and ecobiotechnology, namely to biochemical methods for restoring degraded areas, such as ash dumps of thermal power plants and tailings ponds of the mining industry. The method involves implementing a series of measures to reclaim ash dumps, including surface leveling and loosening, adding peat (up to 4 cm) or soil (up to 2 cm), and mineral fertilizers (100 kg N, 50 kg P₂O₅, 50 kg K₂O / ha in two doses). A mixture of green manure and phytomeliorants is sown on the prepared area: sweet clover (10 kg / ha), brome grass (8 kg / ha), and couch grass (6 kg / ha) at a depth of 1.5-2 cm and covered with an ash layer (2-3 cm). To improve water retention and reduce dust formation, the top layer is treated with a polyacrylamide solution (0.5-0.6 kg / m³ of water, 35 l / m²). Irrigation is carried out with treated wastewater for 14 weeks at a variable rate (30-40 mm / week for the first 8 weeks and 15-20 mm / week thereafter). Bioecological indicators are regularly monitored: grass stand development, root and aboveground biomass formation, generative activity, and changes in soil properties. The method for restoring the ecosystem of ash dumps demonstrates that the proposed set of operations - a thin organomineral surface layer, a balanced grass mixture, a moderate dose of PAA and adaptive irrigation - ensures an accelerated transition of ash into productive technosoil and reliably eliminates the dust load already in the first season of operation. The technical result of the proposed ash dump reclamation method is a comprehensive improvement in the physical, chemical, and biological properties of man-made soils. The use of organomineral preparation, the sowing of resistant perennial grasses, and polyacrylamide treatment help reduce dust formation, increase the water-holding capacity of the substrate, and accelerate the formation of vegetation. Systematic irrigation ensures sustainable grass growth in dry conditions, and monitoring allows for prompt adjustments to agricultural practices. This results in rapid restoration of the soil's protective buffering function, ecosystem stabilization, and a reduction in the anthropogenic impact on the environment.