COMPARATIVE ANALYSIS OF THE FLOW CAPACITYOF SEWAGE NETWORKS DURING RECONSTRUCTION

An analysis of the technical condition of water drainage systems in Ukraine has been carried out, which shows that a significant part of sewer collectors are in critical or emergency condition, posing a threat to the stable operation of engineering infrastructure and requiring immediate technical solutions. The wear and tear of reinforced concrete pipelines, their susceptibility to biogenic corrosion and mechanical stress, as well as significant infiltration in the networks, result in increased load on the drainage networks, higher operating costs and a high risk of accidents. The results of the study show that trenchless reconstruction methods, in particular the ‘pipe-in-pipe’ technology using polymer pipelines, are one of the most effective ways to technically re-equip wastewater networks, allowing not only to extend the service life of the systems, but also to significantly improve their hydraulic characteristics. Hydraulic calculations have confirmed that, under the same operating conditions, polymer pipes increase the flow velocity and flow rate by an average of 40-45% compared to reinforced concrete counterparts of the same diameter. This is due to the low roughness coefficient of the inner surface of polyethylene, thanks to which, even with a partial reduction in the effective cross-section, the throughput capacity of the system is not only maintained but often increases. Pressure sewer networks have significant additional energy saving potential. Reducing pressure losses along the length of the pipeline when using polymer pipes allows for a reduction in the overall energy costs of sewer pumping stations, which makes reconstruction using polymer materials economically viable even in the short term. Overall, the study confirms that trenchless rehabilitation using polymer pipes should be considered a priority for the modernisation of wastewater systems.