EFFECT OF PHYSICOCHEMICAL PARAMETERS OF SLUDGE AEROBIC EXOTHERMIC STABILIZATION ON THE VIABILITY OF ASCARIS-SUUM EGGS

A laboratory aerobic exothermic stabilization of the primary sewage sl udge within a mesophilic and a thermophilic temperature range and at c onstant aeration of 0.7 1.min(-1) was studied for its lethal effect on Ascaris suum eggs. The mesophilic aerobic stabilization reached the m aximum temperature of 33.3 and 38.7 degrees C, with 37.2 to 33.4% of e ggs surviving. The thermophilic aerobic stabilization with the maximum temperature of 48.5 degrees C destroyed all eggs. Controls showed fro m 84.6 to 91.5% of viable eggs. A statistical evaluation has proved th e dependence of the percentage of viable eggs and the temperature, pH and dry matter (P<0.01) as well as on chemical oxygen demand (COD) (P< 0.05). We have not determined the relation of the surviving eggs eithe r to the content of ammoniacal nitrogen, total nitrogen and phosphorus or to the percentage of organic substances throughout the aerobic exo thermic stabilization.