Lime soil conditioner based on soda production sludge for reclamation of industry-disturbed soils in the impact zone of an oil refinery

Institute for Environmental Protection, Perm National Research Polytechnical University, 614990, 29, Komsomolsky prospekt, Perm, Russia

^* Corresponding author: kalininaelena1@rambler.ru

Abstract

The paper presents the results of a study on the use of soda production sludge (SPS) as a lime soil conditioner. SPS with a less than 0.1 mm fraction is the most suitable in terms of physical, chemical, and toxicological properties and meets the requirements of GOST-14050-93 «Limestone (dolomite) dust. Specifications» on the content of the active substance, the mass fraction of calcium and magnesium carbonates. Reclamative properties of SPS were studied on soil samples taken in the territory removed from the sanitary protection zone of the oil refinery. It was found that all soil samples have a phytotoxic effect on pea seedlings. The introduction of SPS in amount of 1-3 g per kg of soil stimulates the development of the ground part and roots of oats and peas, and also increases the germination energy of oat and pea seeds in the initial soil samples by 2÷10 times. The introduction of SPS into the samples of the studied soils at a dose of 1-3 g/kg stimulates the development of colonies of Azotobacter bacteria and leads to an increase in the total number of soil microorganisms. The introduction of SPS in an amount of 3 g per kilo of soil leads to a slight increase in the environment reaction and an increase in the content of water-soluble salts in the soil up to 2 times. In view of this, it is necessary to control that the content of water-soluble salts does not exceed the established standards. Based on the results obtained, we consider it expedient to use soda production sludge as a lime soil conditioner and for the reclamation of industry-disturbed soils.