Utilization of Organic Substrates for Remediation of TENORM Waste Generated from Some Strategic Industries

The reduction of the enhanced naturally occurring radioactivity in the TENORM residues associated with some strategic industries has become an inevitable task. Therefore, the insoluble sulfates of radium-isotopes (²²⁸Ra, ²²⁶Ra, ²²⁴Ra) have been reduced into soluble sulfides using certain reactive organic carbon as an electron-donor. It is found that all the studied TENORM scale, sludge and phosphogypsum (PG) waste release radiological health hazardous for the public and/or workers contributed mainly to Ra-isotopes and/or their progenies such as radon gases (²²²Rn and ²²⁰Rn) and lead-210. Furthermore, the removal of the \(\gamma\) $\gamma$ -emitters was influenced by the organic carbon sources polarity and waste constituents. Therefore, the removal efficiency (R%) took place as scale > PG > sludge; and correlated positively with polarities of organic substrate as lactic acid (LA) > methanol (MeOH) > ethanol (EtOH) > propanol (nPrOH). As a result, ~ 25, 60 and 75% of total \(\gamma\) $\gamma$ -emitters were removed from sludge, PG and scale wastes using 5% LA solution, respectively. It can be concluded that the treatment can be attributed to the promising bioremediation process by certain sulfate-reducing microorganisms (SRM) for the conversion of the insoluble ^228,226,224Ra-sulfate (electron-acceptor) into more soluble Ra- species such as sulfides (S²⁻), hydrogen sulfides (HS⁻) and/or bicarbonate (HCO₃⁻) in presence of reactive organic substrate (electron-donor).