Rapid Sand Filtration 2D — Headloss & Backwash Cycle

Raw water enters a rapid gravity sand filter carrying suspended turbidity that must be removed before disinfection. This 2D cross-section models the ten-layer depth of a real sand bed with the Iwasaki filtration law and the Carman–Kozeny headloss equation running side by side: as each layer traps particles its local filter coefficient fades and its porosity shrinks, so a visible clogging front creeps downward through the bed while headloss climbs and effluent turbidity slowly rises toward breakthrough. Dial in the influent turbidity, filtration rate and sand grain size to see how each trades off run length against water quality, then trigger a fluidized backwash — or let auto-backwash catch the run at its headloss or turbidity limit — and watch the bed reset to a clean state.