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This article presents the results of a pilot study on the treatment of sludge from a water treatment plant in the city of Almaty, Republic of Kazakhstan, to ensure further disposal. The main objective of the study was to compare the efficiency of sludge drying by natural and artificial methods. The qualitative characteristics of the leachate from the dewatering unit, the chemical composition of the dried sludge and the granulometric analysis of the dried sludge were also studied. The greatest reduction in moisture content was recorded for drying in natural conditions (2.1%), but this process required the longest drying time. The leachate obtained from sludge dewatering was characterized by significant contamination (e.g., turbidity—55.65 on average, color—67.7, total Fe—5.15 mg/L, total N—79.6 mg/L, COD—311 mg/L, BOD—336.15 mg/L), which indicates the need for its pretreatment before further management in the technological system of the treatment station. The content of chemical substances contained in the dry residue of the sludge was also determined, of which aluminum was 0.94–13.8 mg/kg, silicon was 50.24–146.3 mg/kg, potassium was 1.72–5.51. mg/kg, calcium was 71.8–79.1 mg/kg, iron was 2.0–7.54 mg/kg and nickel was 0.9–4.4 mg/kg. A particle size analysis of the dried sludge showed that the majority fractions were fine and very fine sand, with a total of 20.2%, and silt and clay, with a total of 78.3%. Such properties justify the rationality of considering the reuse of dried sludge as a raw material for making, for example, construction materials or soil remediation material. [ABSTRACT FROM AUTHOR]

The geologically complex Kyzylzharma groundwater field is located in the south-central part of Kazakhstan in the lower Syr Darya Basin. It supplies the 243,000 population of Kyzylorda City by drinking and agricultural water needs. Numerical modeling was used to predict the consequences of increased groundwater withdrawal for future water supply needs. The results displayed a mean squared error for the groundwater simulations of about 0.6 m and was thus acceptable. The validated transmissivity was between 2 x 10-7 and 2 x 10-5 m/d. These parameters showed that the planned groundwater withdrawal will result in a depression cone reaching 90-100 m below present levels in 2040. Maximum groundwater level drawdown may reach 130 m below present levels. This drawdown increases risks for brackish saltwater intrusion into the main groundwater aquifer. The results point at the depletion of groundwater resources in the Syr Daria Artesian Basin and the risks for groundwater quality, particularly increase in mineralization. The key outcome is the recognition that effective joint management of the Syr Daria Artesian Basin's groundwater resources, involving both Kazakhstan and Uzbekistan, necessitates development and operation of a joint numerical aquifer model. Building this model is a crucial tool for assessing the sustainable groundwater resources in the region. [ABSTRACT FROM AUTHOR]

The paper presents the results of laboratory studies on the removal of phosphate in a wastewater treatment plant by adding sludge formed at the water treatment plant (water treatment sludge—WTS) in the city of Astana (Kazakhstan). Raw WTS from the sludge drying beds was used in the study, and the content of chemical compounds present in the dry sludge residue was determined, yielding 10.8–14.6% aluminum oxide (Al2O3) and 4.58–5.31% iron oxide (Fe2O3). The sludge moisture ranged from 90.5 to 95.6%, and the ash content ranged from 51.3 to 63.9%. The raw sludge from the WTP was added to the wastewater collected before the sand trap and after biological treatment. On the basis of the obtained test results, it was found that the effect of phosphate removal depended primarily on the sludge dose and was above 90% when adding 50 mL of sludge to 1 L of sewage. To a lesser extent, the effect of phosphate removal was dependent on the contact time of the sludge with the wastewater and the place where the wastewater sample was taken. [ABSTRACT FROM AUTHOR]

This article presents the results of research intended to obtain a complex alumina-iron reagent based on natural diatomite and industrial products of alumina production for wastewater purification from hydrogen sulfide. The material composition of the obtained samples using X-ray diffraction analysis was determined. The results of interaction research in the NaFeO2 - H2S - H2O system at 25°C are given. The results of research on wastewater purification from hydrogen sulfide in Almaty city with the use of ferric sulfate, ferric chloride, sodium ferrite and a complex reagent containing iron at the content of 5.1 mg/l H2S in the initial sample of wastewater were presented. [ABSTRACT FROM AUTHOR]

This article presents the results of studies on the comprehensive assessment pertaining to the peculiarities of nutrition, accumulation, transit and discharge of groundwater in the adjacent territory of the Sorbulak reservoir. The information about the waste water storage was presented. The results of the analysis and decryption of satellite images, as well as the results of aerial photography of the territory of the Sorbulak were presented. The results of field route studies of the work area were presented to identify the external manifestations of directional filtration, areas of exits to the daytime surface of groundwater. The results of the calculation of the filtration flow controlled by the Sorbulak storage lake, unloading through the western side of the plateau into the Kurty River, were presented. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This article presents the results of experimental studies pertaining to the suckling improvement of secondary clarifier in an aeration station in Almaty. According to the obtained research results, the work of secondary clarifiers was evaluated for the removal of suspended solids, concentration of returned sludge and sediment moisture. The technical specifications of aerations, secondary settling tanks and cesspool emptier in the aeration station of Almaty were defined. Additionally, it was shown that the use of the articulated sucker with movable scrapers can increase the efficiency of cleaning the bottom of the circular tanks. In this practical test, the proposed suckling radial settler in aeration station of Almaty during the year showed that the sucker reduces the costs for the installation and maintenance of cesspool emptier and has no damaging effects on the bottom of the sump. [ABSTRACT FROM AUTHOR]

The purpose of this research was to prove that a hybrid system including activated sludge and biofilm attached to carrying media (natural zeolite) could 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 pretreatment. 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). Results from the study showed a significant improvement of treatment efficiency for all examined parameters (BOD, 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 both of activated sludge and biofilm. [ABSTRACT FROM AUTHOR]

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 (BOD5, 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The article presents the results of an experimental study on the clarification of biologically treated wastewater in a clarifier with a suspended sludge layer. The pilot plant was receiving effluent from trickling filters treating municipal wastewater. An experimental clarifier worked under steady-state conditions considering the influent characteristics and variable operating parameters in terms of flow velocities and height of the suspended layer. From the experimental dependences between different technological parameters it was found that the optimum range of the upward flow velocities providing a dynamic equilibrium of the suspended layer was 0.6–1.4 mm/s. Upward flow velocities below 0.5 mm/s can lead to sludge compaction at the bottom of the unit, while values greater than 1.8 mm/s may cause sludge washout. It was also found that higher suspended layer height values favor higher efficiency of the clarifier and can achieve suspended solids in the discharge of less than 5.0 mg/L; this height should be greater than 0.6 m Technological efficiency of the experimental clarifier was significantly higher than the conventional unit and was comparable with tertiary treatment technologies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]