The Centralator™ is a four-cell cluster filter, usually of concrete construction but can be fabricated from steel as well. The Centralator™ has a capacity range from one MGD to 30 MGD and beyond with multiple units. The Centralator™ is a cost-effective process that requires no backwash pump or pipe galleries. When Simul-Wash™ is incorporated, the Centralator™ is an excellent system for tertiary/wastewater applications as well as large flow potable water plants.