Introduction. It is widely known that the operation of sewage treatment facilities requires a significant amount of energy, consumed by the pumping equipment, the automated control system, lighting, heating, ventilation, etc. To ensure the reliable operation of pressure sewerage pipelines, it is necessary to analyze the flow parameters and adequately protect these structures from pressure surges (fluid shocks), that demonstrate unique features in the process of wastewater discharge. The proposed method of analyzing principal hydrodynamic parameters in case of a fluid shock takes into account the multi-phase nature of the pressure flow. The hydrodynamic cleaning of water supply and sewerage networks involves special equipment used to clean pipes, having the diameter of over 150 mm which are made of any material. The process of the hydrodynamic cleaning of networks is expensive and laborious. Therefore, the authors of the article propose to prepare a preliminary justification report for such an expensive operation. The purpose of the research is to identify the pipe characteristics, that can justify the application of the hydraulic method for the removal of a layer of internal deposits. Materials and methods. Dependencies, derived by the authors for the purpose of the hydraulic analysis of gravity drainage networks, are used in the article. Results. Dependence between the actual pipe filling and the thickness of the sediment layer in the pipe gully was confirmed. A specific example is provided by the authors to confirm the existence of such a dependence. The graph shows dependence between the actual pipe filling level and the thickness of the sediment layer in the gully and dependence between the value of the hydraulic slope and the thickness of the actual sediment layer. Conclusions. It is shown that the hydrodynamic cleaning of pipes, having a gully sediment layer exceeding 70 mm, is justified for the case analyzed in the article.

During operation, pipeline hydraulic characteristics change due to the presence of sedimentary layers in pipes. The efficiency coefficient in an important parameter for the evaluation of the pipeline operation.Purpose: The aim of this work is to prove the necessity of using the efficiency coefficient in the hydraulic analysis of water supply and removal with internal sedimentary layers in pipes in order to predict their hydraulic characteristics with any (measured) thickness of the sedimentary layer.Methodology: Dependences used herein are repeatedly published by the authors.Research findings: Calculation tables are developed to design the reference manual "Calculation tables for hydraulic analysis of water removal in pipes with sedimentary layers".Practical implication: The proposed values of the efficiency coefficient of water supply and removal can be used in hydraulic calculations to predict the hydraulic potential of pipes with sedimentary layers.

Introduction. The purpose of the research is to establish the criterion for assessing the pipeline operation efficiency and verify the accuracy of hydraulic design of metal pipes that have internal deposits. Materials and methods. The authors provide calculated dependences to determine the values of the characteristics of the hydraulic potential of metal pipes having internal deposits. A specific case is employed to compare the characteristics of new pipes and pipes having different thicknesses of the layer of internal deposits. The percent discrepancy between pipe characteristics is provided. Results. The authors recommend evaluating the accuracy of the hydraulic design of water supply and sewerage networks having internal deposits in reliance on the value of the operation efficiency coefficient for water supply or sewerage networks. The authors offer a formula derived to determine the value of the efficiency coefficient for the operation of water supply and sewerage networks having internal deposits on inside walls of a pipe. The authors suggest systematizing the hydraulic design of metal water supply and sewerage networks that are made of metal and have deposits on the inside of pipe walls by taking into account the thickness of the layer of internal deposits, characterized by the value of the network operation efficiency coefficient. Conclusions. Systematization of hydraulic design of water supply and sewerage networks that are made of metal and have deposits on the inside of pipe walls allows for the acceptable accuracy of its hydraulic design that takes account of the actual value of the coefficient of efficiency of pipeline operation Kef, taking into account the value of actual thickness of deposit layer σact. In other words, systematization of hydraulic design of water supply and sewerage networks, having deposits on the inside surface of metal pipes, is based on the value of their efficiency coefficient Kef, that takes into account the actual hydraulic potential of pipes (pipelines) depending on the layer of internal deposits σact.

The practice of operation of gravity sewer networks of domestic wastewater shows that sediment de-posits are formed in the chute section of pipes at certain velocities of the gravity flow. These deposits affect the hydraulic characteristics of the flow, which depend on the actual thickness of the sediment layer in sewer pipes. In this study, a velocity diagram reflecting the distribution of actual velocity values of wastewater flow along the depth of the wetted perimeter of pipes with sediment deposits in their chute sections is established. To this end, the dependences derived by the authors previously for hy-draulic calculation of drainage networks with internal sediments were used. It is confirmed on a specific example that the limiting value of sediment thickness preventing the continuation of further operation for concrete pipes with a diameter of 400 mm equals 80 mm. The obtained diagram of the vertical ve-locity distribution of sewage flow can be used to determine the actual pipeline fill level corresponding to the actual sediment layer thickness in sewer pipes.

Supplying population of small municipalities with drinking water brings up a number of problems. The main ones are water production, its treatment and transportation. Studying the difficulties of supplying population with drinking water makes it possible to identify acute problems and to outline the prospects for the development of water supply systems. The statistical data on water supply problems are given. The dynamics of aging water systems is presented. Various water supply schemes are considered. There are highlighted unique details of each water supply system, that require an individual approach, careful preparation and analysis of the initial data, and performance of quite complex technical and economic calculations. The options for combining existing systems and their reconstruction are discussed. Water supply systems with a water tower are analyzed. Ways out of the crisis in water supply field are suggested.