Sludge scrapers for circular tanks utilize either central drive or peripheral drive. This depends on the process, tank diameter, design and sludge loads. Circular scrapers can be studied through various classifications. They can be classified as central driven fixed bridge scrapers and peripheral driven rotating bridge scrapers with regard to their drive. The length of a rotating bridge scraper can be equal to the basin diameter or a fraction of the basin diameter. The solid load of the treatment plant determines the method of sludge disposal. The sludge that accumulates at the bottom can either be scraped into the sludge funnel or be pumped to the pipeline of the central structure by suction pipes. Numerous options can be proposed for both methods.