EVALUATION OF THE COMPOSTING PROCESS THROUGH THE CHANGES IN PHYSICAL, CHEMICAL, MICROBIAL AND ENZYMATIC PARAMETERSA.I. KHALIL, M.S. HASSOUNA, M.M. SHAHEEN AND M.A. ABOU BAKRAbstract Evaluation of the composting process at three compost plants (Abis-I, Abis-II and El- Montaza) through the changes in physical, chemical, microbial and enzymatic parameters was investigated. The results showed that the temperature increased and reached the maximum and then slowly decreased. The temperature remained almost steady at high temperature throughout the composting period except during the winter season. The unpleasant odour decreased with time but not completely disappeared. A gradual darkening of colour was evident. The colour of the final composts was light brown, except that found at El-Montaza plant in the winter season it was nearly dark brown. Moisture content decreased with time. Marked changes in pH values were found. C/N, C/P and C/K ratios decreased with time. This decrease was higher in the winter season than in the other seasons and the highest decrease was found at El-Montaza plant. The mesophilic bacteria decreased with time, whereas the thermophilic ones increased and reached the maximum after 10 days and then decreased. The mesophilic fungi appeared at the beginning and then decreased and disappeared after a period differed from 10 to 20 days, whereas the thermophilic ones disappeared at the beginning and appeared after 10 days and then disappeared after a period differed from 20 to 30 days. The maximum activity of α-amylase was found at the beginning and then decreased. The activity of CMCase increased and reached the maximum after a period differed from 10 to 30 days and then decreased. The activity of xylanase increased and reached the maximum after 30 days and then decreased. The activity of enzymes was higher in the winter season than in the other seasons and the highest activity was found at El-Montaza plant.
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