MICROBIOLOGICAL DESCRIPTION OF KYIV SEWAGE AND ENVIRONMENTAL ASSESSMENT OF FITNESS FOR USE IN FARMING

Abstract

In recent years it was indicated that a catastrophic water pollution of planet by wastewater anthropogenic origin. This problem is important also forUkraine. The shortage of water in its streams discharged large amounts of contaminated wastewater because of their ecological condition is critical. With biological positions the only way to protect water bodies is prevention of discharges of wastewater. The most rational way of recycling waste water is their inclusion in the biological cycle. World experience shows the feasibility of their use for irrigation of agricultural land for the purpose of soil purification and recycling. A decision on the feasibility of sewage for irrigation must have systematic information on the comprehensive assessment of their suitability to prevent negative consequences. Along with other important diagnostic indicators of environmental acceptability of waste water for irrigation is ecological and microbiological data: the number of microorganisms in specific ecological - trophic groups, the specificity of microbiota’s functional orientation, the degree of phytotoxicity and others. This knowledge will make it possible to predict the impact of wastewater on the ecological state of soils, developing proactive measures in accordance with the environmental situation, and others. There is no such information about the biologically treated sewage of Kyiv.

 Goal. To evaluate the quantitative and functional characteristics of microorganisms biologically treated sewage of Kyiv, to establish the degree of their phytotoxicity and justify their forecast impact on the ecological and biological properties of soils.

Methods. The biologically treated wastewater of Kyiv was investigated in 2014-2015. Samples were taken in dynamics during May-September after secondary clarifiers of Bortnichy aeration station WWTP JSC AK "Kyivvodocanal" in the output channel fault. For comparison, analyzing river water samples which were taken in dynamics during May-September thru Dnipro River within the bounds of Kyiv (near Metro Bridge below100 m in the flow) and the Dniprovska water intake pumping station of Bortnichy Water Resources Management named by M.A.Harkusha.Ukraine. Determination of the number of microorganisms specific ecological- trophic groups in samples of sewage and river water was conducted at theInstitute ofAgricultural Microbiology and agricultural production of NAAS by conventional methods. The method of sowing dilutes suspensions used in appropriate dilutions on selective nutrient media. The number of ammonium-fixing microorganisms studied on the meat-peptin agar and bacteria that metabolize mostly mineral compounds of nitrogen on starch-ammonia agar, phosphate-containing bacteria on the medium with tricalcium phosphate and glucose-aspartic environment, cellulolytic bacteria on the environment of Inshenetskiy’s and Solntseva’s environment and Micromycetes on Capek-Dox’s nutrient media. Phytotoxicity of sewage and river water determined by Krasilnikov’s method with the use of seed corn as test culture. Besides, the tap water served as a control option.

Results. Industrial waste water after treatment parameters are characterized by relatively high content of phosphorus and nitrogen microbial natural cycles (in millions 1 ml), which indirectly indicates the presence of appropriate substrates in biotransformation are involved indicated biota. It includes a small amount of cellulose-decomposing bacteria, micromyceta found in some samples.

In relation to higher plant the wastewater doesn’t have sharply pronounced toxic properties.

The river water, sampled within the bounds of Kyiv, is characterized by a relatively high number of individual eco-trophic groups of microorganisms, the

Exception -cellulolytic bacteria in river water are not found. Two samples of water present in sufficiently large quantities of microscopic fungi. In these samples revealed phytotoxic symptoms which can be explained by the presence of phytotoxic forms of fungi. In terms of individual selection found phytotoxic properties of river water, but since this effect not systemic, it probably explains the unauthorized dumping referred to the river in the city of toxicants from untreated sewage.

In river water, sampled in the Dnipro water intake pumping station of Water Resources Management of Ukraine, the number of microorganisms phosphorus and nitrogen natural cycles one to two orders of magnitude lower than the number of parameters in their biologically treated wastewater and river water samples taken from the channel within the bounds of Kyiv. It is not found Micromycetes, water tap did not differ from the effect on germ culture test, which indicates a high buffer capacity ofDniproRiver.

Consequently, research phytotoxicity biologically treated sewage of Kyiv and content of some representatives of ecological - trophic groups of organisms indicate that their use in agriculture for irrigation is promising. Absence of phytotoxicity in wastewater after biological treatment and the presence of microbial nitrogen and phosphorus cycles describing them as a favorable source for irrigation. These findings are reinforced by the results of studies of river water. As for irrigation usually river water is used, its quality indicators can be used as a new standard. Comparison parameters of biologically treated wastewater with indicators of river water quality indisputable evidence of biological wastewater treatment and their suitability for practical use.

Perspectives. A prospect for future research is to study the impact of irrigation by biologically treated wastewater on number microorganisms of individual eco-logical - trophic groups of soil.