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...

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...

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 storage of sewage sludge in landfills is still the primary method of their disposal in many countries. Therefore, finding sustainable solutions for the reuse of this waste is an important issue to be addressed. This paper presents the results of research on processing sewage sludge generated at the wastewater treatment plants of Almaty, Kazakhstan, for use in the manufacturing of ceramic bricks. The chemical composition of the sewage sludge was determined, showing the presence of 35.7% silicon dioxide, 7.3% aluminum oxide, 11.2% iron oxide, and 10.6% calcium oxide. Experimental studies established that adding sewage sludge to clay reduces the compressive strength of ceramic bricks while increasing their flexural strength. Furthermore, as the proportion of sewage sludge in the clay mixture increases, the average density of the ceramic bricks decreases, while water absorption increases. It was also found that ceramic bricks made from a mixture of 90% clay and 10% sewage sludge demonstrated the best physico-mechanical properties. This composition showed increased flexural strength and a simultaneous reduction in the average density by 15.4%, indicating the improved structural quality of the manufactured bricks.

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.

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.