Helminth eggs in wastewater: quantification technique

In the framework of agricultural wastewater reuse, the W.H.O. has defined a parasitological quality for sewage with less than one nematode egg per liter. The purpose of this work is to define an effective method to detect helminth eggs in wastewater. Seven techniques have been applied to waste water analysis, with a comparison of their respective results, varying from 26 to 74 %. Be it in the framework of artificial contamination or on site, the best results were obtained with the diphasic technique perfected at the laboratory including a treatment with antiformine at 8 % + ethylacetate followed by a flotation with zinc sulphate at 55%. The validation in the laboratory of the methods performance on treated wastewater allowed us to show that the yield of the method is significantly independent of the egg concentration as well as giving good homogeneity of results with a concentration of 1 egg/litre.