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The presented work is devoted to solving the actual problem of increasing the efficiency of rapid sand filters with granular filling, which operate at a constant filtration rate when cleaning suspensions with a relatively high concentration of contaminants. The proposed mathematical model for clarifying the suspension by filtration consists of three interconnected blocks: clarified, filtration, and hydraulic. Convenient dimensionless mathematical dependencies are obtained for calculating the concentrations of contaminants and sediment from the height of the filter and suspension in the filtrate; head loss in the filter loading; the effective time of the filter (the duration of the filter cycle). The design of the experimental setup and the methodology for conducting experimental studies and mathematical processing of the results are valid. The results of experimental studies of the suspension filtering process through the granular loading are presented, and the obtained data is analyzed. Measurement of pressure losses in the filter loading is performed when a suspension is passed with a relatively high concentration of contaminants at various filtration rates. The nature of the change in the filtration rate with time and height (length) loading at various filtration rates and initial contamination concentrations is determined. Measured variable concentration of suspended matter in filtered water and retained contamination over time. As a result of the experiments, it is confirmed that an increase in the concentration of retained contaminants S leads to an increase in the parameter Δn/n. Upon reaching a certain value of the concentration of the retained sediment S (in our case S=30 g/dm3), an increase in the relative specific volume of the sediment greater than Δn/n0=0.65 is not observed. It is established that an important characteristic of the retained sediment is the ratio of the volume concentration of the sediment to the volume concentration of solid particles in this sediment γ=Csd/Сs. The values of the adhesion and detachment of particles of contaminant in the particles of the material loading =4,9; =0,009. The results of experimental studies in general confirm the correctness and reliability of the obtained analytical dependencies.

This paper reports the results of the experimental and theoretical studies of the characteristics of perforated pipelines, which are used to collect and dispose water from capacitive treatment structures of water supply and sewerage systems.The value and nature of the change in the flow rate through the perforation holes µ col lengthwise a pipeline have been examined depending on the design characteristics of the perforated pipes and parameters of a fluid flow in the pipeline. Measurements were carried out at a specially assembled experimental bench. The experiments determined the nature of changes in the flow rate value, as well as in the piezometric line along the collector. The obtained data showed that the flow rate factor µcol varies along the length of the collecting channel. Its value depends on the ratio of the velocity of the fluid jets that enter the pipe to the average velocity in the examined cross-section (U h /V). In this case, this ratio also changes along the path; it has a maximum value at the beginning of the pipe and a minimum value at its end. The variable flow rate factor of perforation holes, on the contrary, had a minimum at the beginning and a maximum at the end of the collector. The result of the analysis of initial equations and the findings based on experimental data has shown that calculations may assume, without a significant error, the flow rate factor value of perforation holes µ col to be constant lengthwise the collector. The impact of the transit flow rate on the value of this coefficient has also been estimated. It is shown that the increase in transit leads to a certain increase in the flow rate factor, which is averaged for the entire collector. The paper proposes empirical dependences that are convenient to use in order to calculate the flow rate factor, both variable and constant, for the case of the presence and absence of transit in the head drainage channel

Most production technologies require a uniform flow path of liquid from pressure distribution pipelines. To achieve this goal, it is proposed to introduce polymer additives into the liquid flow or to use converging distribution pipelines with a continuous longitudinal slot in the wall. To reduce the uneven operation of the distribution pipeline during discrete liquid dispensing, it is proposed to use cylindrical output rotary nozzles with a lateral orthogonal entry of the jet into the nozzle. The problem is the lack of methods for accurate hydraulic calculation of the operation of distribution pipelines. Adequate calculation methods are based on differential equations. Finding the exact solution of the differential equation of fluid motion with variable path flow rate for perforated distribution pipelines is urgent, because it still does not exist. The available calculation methods take into account only the right angles of separation of the jets from the flow in the distribution pipeline. These methods are based on the assumption that the coefficient of hydraulic friction and the coefficient of resistance of the outlets are constant along the flow. A calculation method is proposed that takes into account the change in the values of these resistance coefficients along the distribution pipeline. The kinematic and physical characteristics of the flow outside the distribution pipeline are also taken into account. The accuracy of calculating the value of the flow rate of water distributed from the distribution pipeline has been experimentally verified. The error in calculating the water consumption by the method assuming that the values of the resistance coefficients are unchanged along the distribution pipeline reaches 18.75 %. According to the proposed calculation method, this error does not exceed 6.25 %. However, both methods are suitable for the design of pressure distribution pipelines, provided that the jet separation angles are straight. Taking into account the change from 90° to 360° of the angle of separation of the jets from the flow in the distribution pipeline will expand the scope and accuracy of calculation methods.

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