What Are the Requirements for a Sludge Scraper in a DAF Tank

Solid Liquid Separator September 1, 2025 Dissolved Air Flotation

Equipment Selection
- Small rectangular DAF tanks usually adopt a chain-type scraper.
- For large rectangular DAF tanks (recommended span ≤ 10 m), a bridge-type scraper is commonly used.
- For circular DAF tanks (diameter 2–10 m), a planetary-type scraper is suitable.
Sludge Removal Efficiency
- If large amounts of floating sludge cannot be removed in time, or if the scraping process disturbs the sludge layer excessively, the flotation efficiency will be affected.
- Improper liquid level control or scraping sequence, as well as scraper travel speed being too fast, will also negatively impact performance.
Scraper Travel Speed
- To ensure the scraper plate does not move faster than the sludge overflow rate into the collection trough, the scraper’s travel speed should be controlled at 50–100 mm/s.
Operation Time
- The scraper’s operating time should be adjusted according to the actual sludge load.