Determination of degradation of radioactivity and its kinetics in aerobic composting

In this study, the kinetics of disappearance of radioactivity in aerobic composting was investigated. For this purpose, compost materials were prepared by mixing sugar beet wastes, wine factory wastes (grape wastes), straw and biological treatment sludge in different amounts. While α-radioactivity was not initially detected in all composting materials, the composting materials had some β-radioactivity. In the mixtures of sugar beet wastes–straw–biological treatment sludge (I), sugar beet wastes–wine factory wastes (grape wastes)–biological treatment sludge (II) and wine factory wastes (grape wastes)–biological treatment sludge (III), the β-radioactivity reduced by 82%, 58%, 85% respectively of initial values after 52 d. The β-radioactivity degradation in the composting process could be represented by first-order kinetics and reaction rate constants of mixtures of I, II and III were k=0.0693 d−1 (R2=0.84), k=0.0453 d−1 (R2=0.98), k=0.0234 d−1 (R2=0.97), respectively.