Use of the co-composting time extract agar to evaluate the microbial community changes during the co-composting of activated sludge and date palm waste

Abstract This study investigates changes in the microbiological community of two co-composting mixtures of activated sludge and date palm waste over a 6-month period. The use of the co-composting time extract medium to evaluate the abundance of cultivable indigenous microflora showed that the total microbial biomass was higher during the thermophilic phase. The mesophilic microflora was more abundant than the thermophilic bacteria, throughout the co-composting process. The proportion of mesophilic and thermophilic actinobacteria was high during the maturation phase especially for mixture A. However, thermotolerant fungal microflora increased during the thermophilic stage. Furthermore, correlating physico-chemical analysis of samples with bacterial diversity indicated that the bacterial communities underwent temperature changes. Enterococci and thermotolerant coliforms decreased significantly toward the end of the co-composting process which indicates the safety and sanitization of the end product.