Diagnosis and optimization of the composting process in full-scale mechanical-biological treatment plants

The aims of this study were (i) to evaluate the performance of the composting process operation in full-scale mechanical-biological treatment (MBT) plants, (ii) to estimate their performance under optimized conditions and (iii) to propose specific guidelines on how to improve the efficiency of the composting process. To fulfil these objectives, a first-order kinetic model was used. This model was calibrated with experimental data to account for the limitations imposed by less-than-optimal environmental conditions during operation of the composting process. Data treatment and simulation showed that two of the three MBT plants studied were poorly operated. Optimization of process management with measures of simple practical implementation was estimated to be highly significant in these poorly managed plants, increasing performance by 103% in MBT1 and 53% in MBT2. In MBT3, the potential for optimization was estimated at 17%. Similar results were obtained from the analysis of other published data, suggesting that poor process management in MBT composting is widespread. These findings highlight the importance of having programmes for monitoring and optimizing process performance in full-scale composting systems. The procedures developed here are simple to apply and can routinely be implemented in full-scale plants.