Bacteriological and sanitary evaluation of ponds supplied with biologically pretreated sewage under conditions of fish culture
Abstract
Bacteriological indices of water pollution (TVC 20°C and TVC 37°C) and sanitary indices (TC, FC and FS) in wastewater supplied fish ponds situated at the sewage treatment plant (domestic sewage and fruit and vegetable processing wastes) showed strong pollution of pond 1, considerable pollution of pond 2 and slight pollution of ponds 3 and 4. Bottom sediments of the ponds contained 1000-10000 times more indicatory microorganisms comparing to the water. Pathogenic bacteria of Salmonella genus were occasionally observed in all ponds and their presence might have resulted from activity of the birds, mainly gulls. From bacteriological point of view, in ponds 3 and 4 (situated at the end of the technological series) appropriate conditions for table fish rearing occured during the whole season. In pond 2 favourable conditions were observed tempprarily, when FC densities did not exceed 1000/100 cm3.
