THE INTERFACE BETWEEN FILTRATION AND BACKWASHING

A conceptual model of the initial degradation phase of filtration is presented as an interface effect between backwashing and filtration. It is shown that the initial degradation of effluent quality is due to the backwash water remnants within the media and the backwash water above the media. The two peak characteristics of initial degradation due to the backwash water remnants within the media and above the media is established by an extensive experimental investigation. A mathematical model for the quality of backwash water as a function of backwash water volume is developed. Deductions made from the mathematical expression confirm the validity of some accepted facts on backwashing and also lay the basis for the peaks in initial degradation. Refs.