Review article

The paper considers the problem of increased gas contamination of the sewer network in the areas of drop wells and shafts functioning, which leads to violation of the sewer networks operation standards, deterioration of the surrounding airspace sanitary and environmental conditions and premature deterioration of reinforced concrete structures and pipes due to gas (microbial) corrosion. In order to reduce gas contamination in drop shafts, the use of tube risers made of elastic materials is proposed. In order to investigate the hydraulic regime, there was carried out an experiment that showed the compression of the elastic tube walls providing the performance of the riser with a full cross-section. For the proper estimation of the gas emission intensity in the shaft equipped with elastic tubular riser, there was carried out a series of model calculations in the ANSYS CFX finite element analysis package for the unsteady problem. There were obtained the velocity and pressure fields in water and gas-air media (hydrogen sulfide was assumed as a sewage gas), as well as the volume fraction of water and gas-air media. In comparison with the classical design of the tubular drop, a decrease in the gas content of the subsurface space of the sewer shaft was evident.