Disinfection of seawater for
hatchery aquaculture systems using electrolytic water treatment
M.A.
Jorquera, G. Valencia, M. Eguchi, M. Katayose-2002
Aquaculture, 207(3-4): 213-224
Abstract:
A recently marketed electrolytic water treatment
system (Hoshizaki) was evaluated for disinfection of seawater used in
disease-prone high-intensity aquaculture systems. Bacterial plate counts
(CFU), direct bacterial total counts using 4´,6´ diamidino-2-phenylindole
(DAPI) staining, and viable bacterial total counts using 6-carboxy
fluorescein diacetate (6CFDA) showed complete inactivation of bacterial
populations at an intensity of >/= 1.3 amp (>/= 2.13 mg Cl/l). This
included disinfection of seawater experimentally dosed with the known
scallop pathogen Vibrio anguillarum. Experimental use of electrolysis
between 1.0 and 4.0 A was able to disinfect cultures of the (food) microalga
Isochrysis galbana without deleterious effects on its growth rate.
When this technique was applied on a commercial scale in a scallop hatchery,
higher microalgal growth rates were achieved compared to those of
traditionally autoclaved seawater, or seawater treated with germicidal
ultraviolet light (UV). Results suggested that disinfection of hatchery
culture waters could be achieved using electrolytic release of very low
levels of active Cl- ion, providing an effective and economically
attractive alternative to currently used methods in these culture systems.
(Laboratorio
de Ecología Microbiana, Facultad de Recursos del Mar, Universidad de
Antofagasta, Avda. Angamos 601, Antofagasta, Chile, Tel.:
+56-55-637447; fax: +56-55-637804, e-mail of C. Riquelme: criquelme@uantof.cl)