Disinfection of domestic effluents by gamma radiation: Effects on the inactivation of Ascaris lumbricoides eggs

This work investigated the inactivation of Ascaris lumbricoides eggs in domestic effluents by gamma radiation from a 60Co source. Domestic wastewater was treated in a compact demo-scale system consisting of a UASB reactor and a trickling filter; treatment was carried out at the Center for Research and Training on Sanitation (CePTS), Federal University of Minas Gerais, in Belo Horizonte-MG, Brazil. One-liter of treated wastewater samples was artificially contaminated with an average of 1000 non-embryonated Ascaris lumbricoides eggs from human feces; samples were then irradiated in a multiple-purpose irradiator at different doses (0.5–5 kGy). Eggs were recovered from the wastewater and the viability of these irradiated eggs was evaluated; the description of the egg developmental phases with each dose of gamma radiation was recorded. Radiation doses of 3.5 kGy effectively disinfected effluents with lower concentrations of A. lumbricoides eggs; higher radiation doses of 5 kGy were necessary to disinfect effluents with higher eggs concentrations.

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► We evaluated the use of gamma radiation for wastewater disinfection aiming at the inactivation of Ascaris eggs.
► Samples of treated wastewater were artificially contaminated with non-embryonated Ascaris lumbricoides eggs.
► The eggs were recovered from human feces and presented above 80% of viable eggs.
► Around 60% of the irradiated eggs stopped the development at the gastrula stage. The remaining formed non-viable eggs.
► Gamma radiation doses of 3.5 and 5.0 kGy were capable of inactivating 99.3% and 100% of the Ascaris eggs, respectively.