Particle Behavior in Deep‐Bed Filtration: Part 1—Ripening and Breakthrough

Laboratory‐scale filtration experiments were conducted using sedimentation basin effluent from a local lime‐softening water treatment plant. An electronic particle counter was used to observe changes in the particle size distribution of the filtrate as a function of filter depth and time under a variety of filter operating conditions. The experiments were conducted for an extended period (up to 48 h) to observe the effects of both ripening and breakthrough over the duration of a typical water treatment plant filter cycle. The results indicate that ripening and breakthrough are not distinct stages but occur simultaneously for different‐size particles. The effects of media size and filtration velocity were investigated, and simple normalizations were developed.