Strategic Filter Backwashing Techniques and Resulting Particle Passage

Abstract

A new filter backwashing strategy, extended terminal subfluidization wash (ETSW), aimed at reducing particle passage into the filtered water during the initial filter ripening sequence immediately following backwashing has been evaluated on pilot-scale filters at a conventional water treatment plant using alum as the sole coagulant. Turbidities and particle counts were measured following backwashes extending across a range of ETSW flow rates. The ETSW procedure was effective in significantly reducing the passage of particles through filters that originated from the backwash remnant water flowing out of the filter during the first