Viability of Ascaris suum, Ascaris lumbricoides and Trichuris muris eggs to alkaline pH and different temperatures.

Disposal of wastewater sludges in agricultural soil is a way to recover mineral and organic substances. Nevertheless disposing and handling such untreated, potentially contaminated sludges may be hazardous for human health and the environment. The aim of this study is to evaluate a method for sludge decontamination consisting in alkaline treatment with ammonia at different temperatures (22 degrees C, 30 degrees C, 40 degrees C) to establish its effects on the survival of Ascaris suum, Ascaris lumbricoides and Trichuris muris eggs. Our experiments show that the combination of alkalinization with NH4OH at a temperature of 30 degrees C causes the eggs to be inactivated. A 40 degrees C temperature was unfavourable to the development of these helminths in the eggs, with or without addition of NH4OH. At 22 degrees C ammonia did not have any effect on their viability. Ammonia at suitable temperatures therefore, is able to destroy Ascaris and Trichuris eggs. It is suggested that this technology be adopted to decontaminate wastewater sludge before using it as manure in agriculture.