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Why Grit Must Be Removed First

Abrasive inorganic particles damage plant and accumulate where they are not wanted

Abrasion

Silica sand and grit are hard and dense, eroding impellers, seals and pipework and driving high maintenance requirement.

Deposition

Grit settles in channels, digesters and aeration tanks, reducing volume and disrupting biological processes.

Variable Loading

Grit load surges during storm flow and varies with catchment, demanding a unit that performs across the range.

Design Settling Velocity — Discriminating Grit from Organics

Grit removal targets dense inorganic particles (ρp ≈ 2,650 kg/m³) of 150–200 µm, whose Stokes settling velocity is roughly 20–25 m/h, while retaining lighter organic solids (ρp ≈ 1,050 kg/m³) in suspension for downstream biological treatment. The unit is designed so the surface overflow rate sits between these two settling velocities — capturing grit while passing organics.

Grit Removal Technologies

Selected by flow, headloss, footprint and grit characteristics

Horizontal-Flow Channels

Velocity-controlled channels (about 0.3 m/s) settle grit while keeping organics moving; simple and robust.

Aerated Grit Chambers

A spiral roll induced by diffused air separates grit by density and scours organics, giving clean grit capture.

Vortex & Hydrocyclone Units

Forced-vortex and cyclonic units use centrifugal force for compact, high-efficiency grit removal in a small footprint.

Grit Handling Package

Grit Classifiers & Washers

Screw and cyclone classifiers dewater and wash captured grit for low-odour, low-organic disposal.

Sand Traps & Separators

Robust sand-separation units protect downstream pumps and equipment on industrial and tunnelling duty.

Conveyors & Storage

Grit conveying and storage integrated for continuous, unattended operation.

Sizing a grit or sand removal stage?

Reynolds & Bauhm engineers sediment-removal trains from grit chambers to colloidal polishing, matched to your particle-size distribution and discharge consent.

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.