HYDRAULIC CONDUCTIVITY DEPENDENCE ON POROSITY OF RAPID FILTERS MEDIA

Abstract

Important characteristics of the rapid filters media, such as hydraulic conductivity, porosity and filtration rate, are determined on the basis of experimental research, conducted by the authors. The relationship between these parameters, as well as the nature of their variation in the height of the filter bed, and over time during the operation of the structure is defined. The scheme of the developed experimental setup and its operation is presented. It consists of a filter column, sand filter media with initial porosity n = 0,47. Measurements were performed at different initial filtration rates V0 = 4.08 m/h, 6.93 m/h, 9.78 m/h, 13.04 m/h and concentrations of model contaminants С0 = 50 mg/dm3, 100 mg/dm3. Experimental dependences and relationships between the main experimental parameters were obtained according to the measurements results. Namely, the relationships between the porosity and the filter media hydraulic conductivity, between the porosity and the filtration rate were received. The analysis of the received data is carried out in the dimensionless form. The necessary graphs are constructed and the corresponding empirical dependences are determined. The effect of the hydraulic conductivity of granular media and filtration rate reduction while reducing the porosity of sand is confirmed. It is shown that filter media siltation and the filtration rate don’t change significantly at the initial stages of the filtration process. The intensity of these processes increases over time and reaches its maximum at the end of the filtration cycle.