DRUM FILTER PERFORMANCE IN A RECIRCULATING EEL CULTURE UNIT

The performance of a drum filter of a recirculating eel culture unit w as studied. Electron microscopy scanning micrographs of drum filter pa nels showed a high degree of clogging of the filter mesh (after 4 mont hs of operation). Mean removal efficiency for Total Suspended Solids ( TSS) fluctuated considerably between subsequent sampling periods (9.6- 18.4%). Drum filtration changed the particle size distribution of fish tank drainage water, resulting in increasing amounts (from 56 to 67% of dry weight, before and after filter passage) of the smaller particl e fractions (< 20 mu m), thereby indicating a partial breakdown of lar ger particles during the filtration process. Possible reasons for rapi d filter clogging and suggestions for improvements in filter performan ce are discussed.