Performance of a commercial recirculating alligator production system employing a paddle-washed floating bead filter

A 2.83 m 3 prototype paddle-washed bead filter for combined solids capture and biological filtration was successfully operated in a commercial recirculating alligator ( Alligator mississippiensis) facility. The bead filter was originally designed and operated as a downflow filter but due to operational and water quality problems, it was reconfigured to operate in an upflow mode. Water quality conditions and filter performance improved dramatically, with the upflow bead filter capable of handling the equivalent loading of 10.3 kg m −3 beads per day of 40% protein feed, despite oxygen limitations and hydraulic problems associated with the retrofitted alligator system.