The high content of nitrates in drinking water leads to serious diseases. The creation of biofiltering devices with the longest time of their operation between preventive flushes is extremely important. The purpose of this study was to investigate the features of the functioning of the developed U-shaped submersible denitrifying biofilter during its long-term operation in the piston filtration mode. The denitrification of water by using the method of displacement (piston) biofiltration in a submersible small U-shaped biofilter with immovable carriers of attached microflora in its filter load was studied. As a result, clogging of the pore space of the biofilter in the zone of excess bacterial nutrition is prevented and the vital activity of bacteria is maintained in places where there is no nutrient substrate. It has been shown that, due to adaptive mechanisms, denitrifying bacteria convert nitrate ions into gaseous nitrogen, consuming extracellular polymeric substances. The rate constants of the reaction of reduction of nitrates to molecular nitrogen in different zones of the biofilter under different filtration modes were determined. The activity of the microflora inside the biofilter quickly returns to its original level when a full-fledged external nutrition is resumed. The efficiency of nitrate to nitrogen conversion in the studied biofilter is 94.2±8.9%.

Due to the rapid pace of urbanization, the lead-zinc slags previously located outside the settlement turned out to be within the city of Shymkent and began to pose a serious threat to the environment. Therefore, the purpose of the study was to investigate the impact of lead-zinc slags on the environment of Shymkent. It has been revealed that the fields of ruderal plant species are inversely correlated with the lead content in the soil, for phyto-indication of the state of soils, the most informative indicators are the phytocenotic composition and the projective covering of soils with vegetation. At the same time, the proportion of annual species in the control is 53.5 ± 5.6%; with an increase in the toxic load, their role gradually weakens, reaching from 14496.0 ± 105.1 mg/kg Pb 2+ to 5.2 ± 0.4%. It was found that Dodartia orientalis, Centaurea squarrosa Willd., Plantago lancetofolium are hyperaccumulators of lead ions, while electron microscopic images showed that lead ions accumulate in the intercellular space of plants, forming significant conglomerates of 10-75 nm. The negative influence of lead-zinc waste has been established, which leads to the accumulation of lead in the blood of children and, as a consequence, is the cause of various diseases. The maximum lead content in the amount of 103 micrograms / dl was found in the blood of children in the area of the city, located 800-1000 m from the slag storage site. Developing hypochromic anemia in children indicates its toxic origin. It was revealed that 90% of children have such pathologies as biliary dyskinesia, dental caries, small anomalies of heart development.