Aquarium and Fish Farm Water Disinfection

Ozonation should be selected as a disinfection treatment for marine applications where residual disinfecting agents or toxic oxidation products (chlorinated amines) cannot be tolerated. Ozone is unstable in water and decomposes slowly, with a half-life of approximately 30 min at 25°C. The decomposition rate is dependent on water quality. The half-life of the ozone at 25°C is 50 min in distilled water and 20 min in tap water. Decomposition is substantially accelerated by hydroxyl ions, transition metals and free radicals. The oxidation products of ozonation are usually nontoxic and biodegradable. Furthermore, ozonation leaves the water saturated with dissolved oxygen, important in fish hatcheries or fish farms.

Ozonation disinfects water and saturates it with dissolved oxygen. Ozonation can reduce organic contaminants and waste in fish farm water, allowing water recycling. Ozone concentrations higher than 0.1 ppm should be avoided because they can harm the fish. Research from the National Marine Fisheries Service demonstrates that ozonation destroys undesirable microorganisms with no harmful effects to the fish.

Other Disinfectants. For a discussion of the merits and drawbacks of ultraviolet irradiation, heating, chemical oxidants and metal ions, see Table 8.2.10.

—R.A. Conway, C.C. Walden, L.C. Gilde, Jr., C.A. Caswell, R.H. Zanitsch, E.G. Kominek, J.W. T. Ferretti, L.J. Bollyky

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