ABSTRACT

Grit chambers remove sand, grit, cinders, small stones, and other similar size and weight material.

Grit removal equipment can be velocity controlled, aerated, or of the cyclone degritter design.

Velocity controlled grit chambers have either flow controlled square or rectangular chambers that can be either manually or mechanically cleaned. A chain and flight mechanism or manual cleaning efforts move the grit into a sump or bucket for disposal. Flow velocity should be about 1 ft/sec.

Aerated grit removal systems inject air into a chamber to produce a spiral flow. Air flow is adjusted to provide a spiral movement while keeping the velocity low enough to allow grit to settle out.

Cyclone degritters use centrifuge force in a cone shaped unit to remove grit from the wastewater. Wastewater flows into the upper end of the cone to create a vortex that forces the grit particles to the outside of the rotating flow stream. The grit stream produced falls into a grit washer while the degritted flow leaves the cyclone unit through an opening near the top of the unit.

Grit removed is usually washed to remove organic material prior to its disposal.