It is used in rectangular settling ponds of medium and large scale wastewater treatment systems. Mud, sand, etc. accumulated at the bottom of the settling pond. The materials are linearly scraped from the pool floor with crawler scrapers and directed to the sludge collection pit. The oil and foam formed on the surface are directed to the oil-foam collection compartments by means of scraper pallets. Bridge drive can be by means of movable wheels on concrete or rail.
