Electron transfer capacity as a rapid and simple maturity index for compost.

Electron transfer capacity (ETC) of dissolved organic matter (DOM) is proposed as the maturity index to predict the composting status, based on the fact that the compositions of DOM strongly associate with the degree of decomposition. ETC, including electron accept capacity (EAC) and electron recycle rate (ERR), increases as the composting goes on, showing a close correlationship with the germination index (GI). The correlation coefficient between EAC and GI is 0.9273, and that between ERR and GI is 0.9501. The measurements of these ETC parameters require no chemical reagent preparations before analyses and can be obtained very rapidly. The results of this study indicate that these simply and rapidly obtainable ETC parameters can be potential alternatives to evaluate the composting process.