The pH value increased throughout the composting
because of the decomposition of acid-type compounds
and the mineralization of organic compounds to
inorganic compounds, such as NH4
+-N (Fig. 2-B)
(Paredes et al. 2000). The value of electrical
conductivity (EC) increased at the beginning and
thermophilic phase because of the mineralization of
OM, but decreased at the latter phase which might
be due to the precipitation of mineral salts, the
volatilization of NH3 and the stabilization of OM
(Fig. 2-B).