Protection of water environment from pollution is one of the major tasks in the contemporary world. Nowadays, in the Republic of Kazakhstan ecological situation concerning sewage treatment remains deficient. Raw sewage is often discharged directly onto filtration beds or landfills. Many existing wastewater treatment facilities in cities are in unsatisfactory technical conditions. In many villages and small settlement units the problem of treatment and disposal of sewage sludge from treatment facilities also requires urgent solutions. In this article, the current state of communal sewage treatment in the Republic of Kazakhstan is shown. The technical and technological characteristics of sewage disposal systems, including the cities of Almaty and Astana, are presented. This article is especially aimed at identification of environmental problems related with sewage treatment in the Republic of Kazakhstan.

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The purpose of this research was to prove that a hybrid system including activated sludge and biofilm attached to carrying media (natural zeolite) can improve the efficiency of municipal wastewater treatment. The study was performed using a pilotscale plant installed on Almaty Wastewater Treatment Plant (Kazakhstan) and treated sewage after preliminary mechanical treatment. The investigations were conducted in 2 stages: with installation without packing media (activated sludge only) and packed with zeolite from Chankanaysky field (activated sludge and biofilm). The results from the study showed a significant improvement of treatment efficiency for all examined parameters (BOD 5 , COD, suspended solids, nitrogen compounds and phosphates). Microbiological examination of biomass from the bioreactor indicated high diversity and activity of identified species, proving good conditions for both activated sludge and biofilm.

Due to geographical limitations (lack of natural receivers of treated wastewater) large sewage storage ponds are the main method of sewage disposal in the Republic of Kazakhstan. The paper presents the results of research on the environmental impact of sewage ponds serving the city of Kostanay (Kazakhstan). The scope of the research included the determination of basic quality parameters of raw and treated wastewater, the analysis of the chemical composition of groundwater in the vicinity of sewage ponds, and the analysis of the water quality of the Tobol River. The obtained results showed that efficiency of treatment facilities was unsatisfactory and water quality in the ponds did not meet requirements for surface waters for fishery. Highest contamination of groundwater was observed in sampling points close to the sewage ponds and was decreasing while the distance from the ponds was increasing. Multivariate analysis of the research data indicated that sewage from storage ponds, infiltrating into the ground, may affect quality of groundwater, which in turn supplying the Tobol River may also determine the quality of the river water.

The results of comprehensive research on the status of sewage treatment in Almaty are presented in this article. The results of the reconstruction and modernization of treatment facilities intended to improve the sewage treatment efficiency, including the results of pretreatment of wastewater with excess sludge in the primary clarification tank, and the results of hydrobiological and microbiological analysis of activated sludge in the aeration tank are presented. The analysis of the study results of the chemical composition of incoming, clarified and treated wastewater is presented. Besides, the results of the analysis of the water balance of wastewater are presented.