REDUCTION OF THE VIABILITY OF HELMINTH EGGS IN LIME-TREATED SEWAGE SLUDGE - DOI: 10.13083/1414-3984.v22n01a05

Abstract

The agricultural use of sewage sludge is presented as one of the most viable alternatives for its disposal. However, for its adequate reuse it must first be stabilized. The aim of this study was to determine the concentration of viable helminth eggs present in sewage sludge, to evaluate the survival of the eggs in the sludge submitted to different reaction times with lime and classify the sludge, according to the CONAMA 375 Resolution, regarding its agricultural use. The experiment consisted of three treatments and four replications. The treatments consisted of: reaction of sewage sludge with the lime dose required to maintain the pH greater than 12 for 72 h, reaction of sewage sludge with the lime dose required to maintain the pH greater than 12 for 2 h, and sewage sludge without addition of lime. To compare the concentration of helminth eggs between treatments, generalized linear models were adjusted using the Poisson error distribution corrected for Quasi-Poisson, and submitted to the F-test. The sewage sludge treated for 2 h and 72 h promoted the inactivation of 93.75 and 99.32% of helminth eggs, where after treatment the sludge was classified as Class B and Class A, respectively. From a sanitary view the time of 72 h resulted in a safer sludge for agricultural use.