STUDY OF THE CONDITIONS OF THE WATER COAGULATION PROCESS VOLKHOV RIVER IN WINTER
This article presents the results of studying the conditions of the process of coagulation of the Volkhov River water in winter. It is indicated that the chemical composition of natural waters changes depending on the period of the year. In winter, the water of the Volkhov River is characterized by high oxidability, high color, high total iron content and low turbidity. The study of the coagulation process was carried out with the water of the Volkhov river, selected in winter heated to a temperature of 23°C. Aluminum sulfate, aluminum-iron coagulant, aluminum hydroxochlorosulfate, grade A aluminum hydroxochloride and grade B aluminum hydroxochloride were studied as coagulants. It was found that the minimum value of water color is achieved at a dose of coagulants 32 mg/dm<sup>3</sup> by Al<sub>2</sub>O<sub>3</sub>. When heating cold water, the studied coagulants at the optimal dose almost equally reduce the color, turbidity, and oxidizability of natural water. However, when adding aluminum hydroxochlorides of grades A and B, the aluminum content in the water is significantly less and does not exceed the maximum permissible norm for drinking water.