engleski

THE EFFICIENCY OF ROTATING BIOLOGICAL CONTACTORS IN A CLOSED RECIRCULATING FISH CULTURE SYSTEM

The study considers the performance characteristics of rotating bilogical contactors within a commercial recirculating aquaculture system, and by using the data of other researchers provides the comparison with other biofilter designs. Rotating biological contactors, with the ammonia removal rate of 1, 21 g/m2/day have been demonstrated to be one of the most efficient biofilters available for nitrification of aquaculture wastes. Recirculating aquaculture is one of the solution to an environmentally sustainable and economicalloy feasible aquaculture production and its benefits have been clearly identified (Losordo et al, 2001). By proper use of various unit processe and technologies to recycle and reuse the water, recirculating system design can provide for the control of water quality under intensive feeding regimes. Biological filtration as the reduction of the poisonous ammonia compounds generated by digestion of proteins is a critical determinant of the performance of entire production system. Many types of biofilters are being used in commercial and research aquaculture facilities with differences in choice of working organism, design, material, price, etc. Biofilter design must take into account all of the water quality management criteria, as well as consideration of space and cost efficiency. A rotating biological contactor or biodisc filter is a fixed film bioreactor composed of circular plates aligned on a central axe. The discs are rotated slowly, to alternately expose the biologigically active media to the water carrying nitrogenous wastes, and to the air, providing the source of oxigen to the bacteria. The study considers the performance characteristics of rotating bilogical contactors within a commercial recirculating aquaculture system, and by using the data of other researchers provides the comparison with other biofilter designs. Rotating biological contactors, with the ammonia removal rate of 1, 21 g/m2/day have been demonstrate to be one of the most efficient biofilters available for nitrification of aquaculture wastes.

aquaculture; recirculation; biofilter; nitrification

SAŽETAK Recirkulacijska akvakultura predstavlja jednu od opcija okolišno održive i ekonomski isplative akvakulturne proizvodnje čije su beneficije jasno prepoznate. Pravilnom upotrebom različituh komponenti i tehnologija recikliranja vode, sustav omogućava kontrolu kvalitete vode u intenzivnim hranidbenim režimima. Biološka filtracija kao redukcija toksičnih dušičnih spojeva nastalih probavom proiteina jedan je od krtitičnih procesa koji određuje efikasnost cijelog proizvodnog sustava. Brojni tipovi biofiltera upotrebljavanih u različitim proizvodnim i istraživačkim pogonima razlikuju se po vrsti organizama, dizajnu, materijalu, cijeni i sl. Pri dizajniranju biofiltera trbaju biti uzeti u obzir svi kriteriji održavanja optimalne kvalitete uzgojne vode, kao i potrebni prostor te ekonomska isplativost. Rotirajući biološki kontaktor, od kojih je najčešći biodisk filter, sastoji se od okruglih ploča fiksiranih na centralnu osovinu. Diskovi se polako okreću da bi naizmjenice izložili aktivni biološki medij vodi koja sadrži otopljeni dušični otpad, i zraku kao izvoru kisika. Ovaj rad opisuje karakteristike rotirajućih bioloških kontaktora u komercijalnom re