The sludge scraper, dredge, and sludge thickener are equipment for settling and concentrating. For static sedimentation tank applications We produce type BG(X) peripheral driven and type ZG(X) central driven rotating sludge scrapers. For Rectangular settling tanks we produce type QG(X) moving bridge sludge scrapers, our scrapers also come with suction dredge options and scum removal boards. For thickening we produce type W(B)NG central driven picket fence thickeners and LBG floating sludge scraping boards.The construction material above the water may be carbon or stainless steel or aluminum alloy. The material below the water may be carbon or stainless steel. The section of scraper below the water is a logarithmic spiral. The dredge is hydrostatic or a siphon..