Grit and Screen Separator

The grit and screen separator combines three mechanical pre-treatment processes in one compact unit: screenings removal, sand separation, and dewatering of both fractions. It replaces several separate structures at the head of the treatment line and prepares the wastewater for the biological treatment stage.

Screenings retained on the screen, drum, or bar rack are removed by scraper brushes mounted on a screw conveyor. The screw carries them upward, where they are dewatered, compacted, and washed in sequence, then discharged via a chute into a screenings container.

Pre-screened wastewater flows into a horizontal grit chamber connected to a separator. At this mechanical treatment stage, sand and other mineral particles settle out: the grains slow down and sink freely to the bottom. A horizontal spiral scraper moves the accumulated sand toward the separation section, where an inclined conveyor lifts it out of the unit while simultaneously dewatering it. The dewatered sand is then discharged via a chute into a container.

Optionally, the unit can be fitted with an aeration system. It keeps organic suspended solids in motion and assists their flow toward the biological treatment stage, while also promoting separation of organic from mineral matter, resulting in cleaner extracted sand.

• Screen, drum, or bar rack for screenings removal
• Screw conveyor with scraper brushes
• Screenings dewatering, compaction, and washing zone
• Screenings discharge chute to container
• Horizontal grit chamber with integrated separator
• Horizontal spiral grit scraper
• Inclined sand dewatering conveyor
• Sand discharge chute to container
• Optional aeration system