William F Sarra

US Patent:

41871758, Feb 5, 1980

Filed:

Jun 23, 1978

Appl. No.:

5/918593

Inventors:

Charles V. Roberts - Drexel Hill PA
William F. Sarra - Bridgewater NJ
Peter J. Neuspiel - Media PA

Assignee:

Robert Filter Manufacturing Company - Darby PA

International Classification:

B01D 2324

US Classification:

210 80

Abstract:

A treatment facility has a granular media bed for use in acting upon (e. g. filtering) liquid mixtures, such as industrial and municipal water and wastewater, and employs a backwash operation between treatment operations for cleaning or otherwise enhancing the quality of the bed. A control system for the backwash operation establishes a first backwash rate for washing and scouring the granular media to release suspended solids and/or other impurities from the bed. Thereafter the control system establishes a second and generally greater rate for removing the released impurities from the facility. Preferably the first rate is chosen to just completely fluidize the granular bed, at which point a pressure responsive control system detects a constant differential pressure (i. e. a zero change in differential pressure), and the second rate, which generally is greater than the first rate, is responsive to the temperature of the backwash liquid.