The article presents a study of the hydrophysical properties of modified cement concretes, namely frost resistance and water resistance. The compositions of modified concretes for research are determined. It is established that the use of mineral fertilizer production waste in combination with the superplasticizer "Osnovit Safescreen SPP1" allows to increase the frost resistance, water resistance and strength of concrete composites.

Keywords: heavy concrete, hydrophysical properties, frost resistance, water resistance, strength, porosity, organomineral modifier, waste, plasticizer

The paper reveals the problem and causes of the formation of fetid compounds in the systems of transportation and wastewater treatment. Various methods used at the moment to eliminate and neutralize unpleasant odors, as well as a number of measures to clean the air from fetid compounds are considered. A new method is described to prevent the formation of odors of fetid compounds in wastewater transportation and treatment systems and a device for its implementation using low-intensity cavitation. The scheme of the device for sewage treatment from smells of fetid compounds. The principle of operation of this installation is described.

Keywords: fetid compounds , air purification, biological purification, low-intensity cavitation.