Calculation of the environmental capacity of cooling ponds for cage fish farming

Purpose. The determination of a maximum annual amount of fish reared in cagesm which does not result in the deterioration of the ecological state of water cooling ponds of the Zmiev Thermal Power Plant and Kursk Nuclear Power Plant series Ι and ΙΙ. Methodology. The specific (per 1 ton of farmed fish) nutrient intake necessary for calculations was determined according to the data of own studies. For this purpose, we perfrormed the determination of the input of suspended solids into cooling ponds from cage lines. The calculation of mean fish weight increase during the period of trap exposition bsed on fish farm data allowed calculating the specific input of suspended solids from cages. The effect of artificial feeds and a mixture of feed resideus and fish of fishes collected under cages on water quality were evaluated in the condoitins of laboratory experiments. The effect of fish metabolites on water quality was taken into account according to literature data. Findings. In the specific conditions of the investigated cooling ponds, the environmentally allowable concentrations of biogenic elements are established based on the mineral nitrogen content. With the mean volume of the Zmiev Thermal Power Plant of 40.5 million m3, the total amount of mineral nitrogen, which can be introduced with cage aquaculture residues, is 21.87 tons. When rearing one ton of fish in cages, 91.3 kg of mineral nitrogen get into the cooling pond. Thus, the environmental capacity of the Zmiev Thermal Power Plant cooling pond for cage fish farming is 281.7 tons. Accordingly, the allowable amounts of the production of cage fish farming for the Kursk NPP taking into account N content of 0.406 mgN/dm3 and volume of the cooling pond is 625.5 tons. Originality. For the first time, we calculated the ecological capacity of cooling ponds of the Zmiev TPP and Kursk NPP, series I–II. Practical value. Application of the results presented in the paper will allow creating and developing cage fish farms without disturbing the ecological state of cooling ponds of power plant, on the base of which they are created.