Efficiency of application of municipal wastewater sludge during reclamation of oily gray forest soil

Under the conditions of a model experiment, the effect of granular sludge of urban wastewater on the characteristics of reclaimed gray forest medium-carbonaceous soil with different levels of oil pollution was studied. The main physicochemical and microbiological characteristics of wastewater sludge, information on the content of biogenic elements, toxicity and efficiency of petroleum products destruction in soil samples incubated with and without granulate under different approaches to reclamation are presented. The introduction of granulate of wastewater sludge into oily gray forest medium-carbonaceous soil enriches the microbial pool, leads to an increase in the carbon content of the microbial mass. The additional introduction of biogenic elements with granular sediment of wastewater increases the resistance of microbocenoses to pollutant, reduces the time for restoration of properties and fertility of oily soil. It has been shown that the introduction of granular sewage sludge into soil samples containing 2.7-19.7 g/kg of petroleum products at the rate of 10 t/ha leads to 1.7-2.5-fold intensification of destruction processes, reduces the toxic effect of the pollutant, which indicates the possibility of its effective use in the reclamation of oily soils.