A multimedia filter (MMF) is a pressure or gravity vessel containing graded layers of anthracite, sand, and garnet that removes suspended solids and turbidity from RO feed water before cartridge filtration. Feed flows downward through coarse anthracite (top), medium sand (middle), and dense garnet (bottom). Coarser particles are caught high in the bed; finer particles penetrate deeper. Periodic backwash fluidizes the bed and discharges captured solids. MMF is the workhorse particulate-removal stage upstream of cartridges and RO. It handles feeds with 10–100 NTU turbidity that cartridges cannot economically service. A well-operated MMF typically delivers SDI₁₅ < 3 from raw seawater feed with < 1 NTU turbidity. Every 24–72 hours depending on solids load. Triggered by ΔP rise (typically 0.5–0.7 bar above clean) or scheduled time. MMF is cheaper and proven for low-fouling feeds. UF is preferred for variable-quality coastal feeds with algal blooms or high TOC. ForeverPure has supplied desalination, high-pressure pumps, and energy-recovery devices to commercial and industrial customers since 2003. Contact our engineers for sizing, quotes, or technical support.Multimedia Filter (MMF)
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