Submitted to: Aquaculture America Conference
Publication Type: Proceedings
Publication Acceptance Date: 8/20/2002
Publication Date: 1/20/2003
Citation: PFEIFFER, T.J. AIR SCOURING EFFECTS AND CONTROL ON A FLOATING BEAD BIOFILTER FOR A SMALL-SCALE RECIRCULATING AQUACULTURE SYSTEM. SMALL-SCALE AQUACULTURE: PROCEEDINGS OF THE SPECIAL SESSION OF AQUACULTURE AMERICA.2002.P.22-23.
Technical Abstract: The success of biological filtration depends on careful control and management of the nitrifying bacterial biomass attached to the filter media. During the filter backwashing cycle, excess bacterial biomass is removed leaving sufficient bacterial biomass for ammonia removal during the next filter cycle. A useful strategy for removing the excess bacterial biomass during a backwash cycle is air scouring the filter media. A floating bead biofilter was modified to allow for the computer control of several filter media air-scrubbings per day with the equivalent volumetric water loss of a single filter backflush. With several computer-controlled air-scrubbing/solids purging per day (4 per day) the feed loading rate capabilities for the floating bead biofilter was doubled (1.0 lb of feed per ft3 of filter media per day) without a significant reduction in water flow. The peak ammonia removal rate (measured six hours after feeding) ranged between 400 and 700 gram of ammonia removal per m3 of media per day. Based on visual suspended solids settling observations, a three-minute settling time after each air scrub was provide for maximum solids removal. Air-scrubbing of the filter media and purging of the settled solids is one method for enhancing the nitrification and solid removal capabilities of the floating bead biofilter.