Laboratory «Soil Health»

Scientific results:

A technology has been developed for obtaining carbonaceous biosorbents with high porosity parameters from various organic wastes, differing in composition and origin. Two types of plant waste from the south of Russia were used as feedstock: spring barley straw (Hordeum vulgare L.) and common corn (Zea mays). The third type of feedstock for obtaining biosorbents was partially dehydrated and compacted after centrifugal treatment sludge sediments from wastewater from municipal wastewater treatment facilities, selected from RostovVodokanal JSC. A series of experiments were performed to test the temperature modes of pyrolysis (300; 500; 700; 900 °C), heating rates (2.5; 5; 10; 15; 20 °C/min) and raw material holding time (10; 25; 45; 60; 75 min). The results showed that these pyrolysis parameters had a significant effect on the physicochemical, structural and morphological properties of the obtained samples.

The pyrolysis temperature turned out to be a key factor influencing the properties of the biosorbent. The specific surface area of ​​the samples obtained at a pyrolysis temperature of 700 °C decreased depending on the type of raw material in the following order: barley straw (76.43 m2/g) > corn straw (63.68 m2/g) >> sewage sludge (14.02 m2/g). A similar series was observed for the total pore volume, and the opposite for their diameter. Biosorbents from corn straw and barley straw are characterized by a high carbon content and a low ash content. The opposite pattern was found for biosorbent samples from sewage sludge, where the ash content reaches almost 69%, and carbon - only 23%.

An assessment of the environmental safety of the possible use of the obtained biosorbents from sewage sludge was carried out based on the determination of polycyclic aromatic hydrocarbons and heavy metals in them. It was found that an increase in the pyrolysis temperature contributes to an increase in the content of heavy metals in biosorbents from sewage sludge and a decrease in their bioavailability due to an increase in the potentially stable and unstable fractions of metals. With an increase in the pyrolysis temperature, there is a decrease in the potential environmental risk (RI), based on the fractional composition of heavy metals in the sample: from 432.6 in the sludge to 151.7 at the maximum temperature (900 oC). Despite the significant decrease in the RI index with increasing pyrolysis temperature, the obtained indicator indicates a significant potential environmental risk of using biosorbents from sewage sludge. Nevertheless, the study shows that pyrolysis is a promising method of treating sewage sludge in order to immobilize heavy metals in biosorbents and emphasizes the possibility of minimizing the harmful effects of biochar by controlling the pyrolysis temperature. Based on the calculations performed, it was found that the safe dose of biosorbents for application to a 0-20 cm layer of ordinary chernozem is 26 t/ha, provided that the optimal technological parameters of carbonization are observed: pyrolysis temperature of 500 ° C, heating rate of 10 ° C/min, holding time of 60 minutes.

Implementation of research results:

An exchange of experience with industrial partners was conducted, and the main scientific results of the project were presented at the III International Scientific Conference "Current State of Chernozems" and the II International Youth School "Monitoring, Protection and Restoration of Soil Ecosystems under Anthropogenic Load", organized on the basis of the Soil Health laboratory. Work was carried out for interested industrial partners to study the degree of soil degradation and methods of their biorestoration with industrial partners.

Education and personnel occupational retraining:

The following qualified specialists (bachelors, specialists, masters) and highly qualified personnel (scientific personnel) from among the members of the scientific team, trained during the reporting period, were trained: 1 doctor of science and 4 candidates of science, 2 laboratory employees were accepted for postgraduate studies, 1 laboratory employee was accepted for doctoral studies. Training of members of the scientific team was conducted for the purpose of advanced training. 16 members of the scientific team received certificates or certificates of training, completion of additional professional education in the amount of 23 pieces.

Cooperation:

1. Biokhutor Petrovsky (IP Head of the Peasant Farm Shchepetyeva N.A.), Rostov Region, Fedorovka settlement
2. GC NPO "Biocenter", Stavropol Region, Nevinnomyssk
3. Agroholding "Steppe"
4. Consulting IT company "AXENIX", Rostov-on-Don
5. Agrarian and Technological Institute of RUDN, Moscow
6. Rostov TPP-2, Rostov-on-Don