INACTIVATION OF ASCARIS SUUM BY AMMONIA IN FECES SIMULATING THE PARAMETERS OF THE SOLAR TOILET

Inactivation of Ascaris spp. eggs by ammonia in human feces with very high moisture content and sludge has been widely documented. Nevertheless, the application of this treatment alternative in dry toilets where human feces have low moisture content has not been explored. This study evaluated the use of ammonia to inactivate 100% of Ascaris eggs in laboratory conditions incorporating the parameters of the solar dry toilet: human feces with low moisture content and alkaline pH, temperature values ranging from 28°C to 45°C, additive created from a mixture of dirt and lime, and 56 days of storage. Ascaris suum eggs were used as a model for Ascaris lumbricoides, and urea was used as the source of ammonia. Closed samples containing human feces mixed with additive and urea at different concentrations (0%, 1%, and 2% urea) were placed with A. suum eggs in duplicates at four different temperatures (28°C, 35°C, 40°C and 45°C). Ammonia, pH, and moisture were measured, and A. suum eggs viability was evaluated. The results suggested that 100% inactivation of A. suum eggs by ammonia could be possible in fecal material with low moisture content (27.5%), supporting the application of this treatment alternative in dry toilet technologies.