High-density adsorbents of bacteria, closed circulatory system containing the same for fish farming and fish fry culture and fishes fed by using this system

摘要

A closed circulatory system for fish farming and fish fry culture containing high-density adsorbents of bacteria in which microbial cells of nitrifying bacteria and denitrifying bacteria are fixed at a high density. This system is composed at least of a water tank unit for fish farming, a pH-controlling unit, an oxygen-supplying unit for elevating the dissolved oxygen concentration, a nitrifying reactor unit and a denitrifying reactor unit. Water discharged from the fish-farming water tank is purified via the pH controlling unit, the oxygen-supplying unit, the nitrifying reactor unit and the denitrifying reactor unit and then returned into the farming fish-water tank. A high-density adsorbent of nitrifying bacteria, in which nitrifying bacteria cultured at a high density have been fixed, is provided in the nitrifying reactor unit, while a high-density adsorbent of denitrifying bacteria, in which denitrifying bacteria cultured at a high density have been fixed, is provided in the denitrifying reactor unit. Also, a chemical solution storage tank is connected directly to the pH-controlling unit so that the pH value of the farming water can be controlled in the pH-controlling unit with a solution of a mixture of sodium carbonate with sodium hydrogencarbonate.