The partitioning of 131I in sludge samples from a wastewater treatment plant

This study analyses the partition of 131I in organic, inorganic and residual fractions from secondary and digested sludge. Due to the microbiological process in the aeration tank, it was found that the secondary sludge sample had the highest 131I content associated with the organic fraction. In the digested sludge, the organic fraction was smaller due to the anaerobic digestion of part of the organic matter. In this case, 131I was also distributed into the inorganic and residual fractions. Based on this second result, the potential volatilization of 131I in the anaerobic digester has been assessed. The results showed that this radionuclide was not present in air samples, and therefore the potential exposure through inhalation would be negligible for WWTP workers.