Comparison between dry and wet fermentation of biomasses as result of the monitoring of full scale plants

The first agricultural dry anaerobic digestion plant realized in Italy was monitored from the start-up, for over a year. The plant is fuelled by manure and other biomasses, corn silage in particular. The installed power is of about 910kWe. Biogas quality, biogas yield, energy production, labor requirement for loading and unloading operations were monitored. The results of the monitoring were compared to performance data obtained in several full scale wet digestion plants. The dry fermentation plant showed a set up phase that lasted several months during which the average power resulted of 641 kWe ( 70,4 % of nominal power), in the following period the power resulted of 788 kWe ( 86,6 % of installed power). With a correct feeding of digesters, the dry fermentation process showed biogas yields similar to wet anaerobic digestion, congruent to the energy potential of the biomasses used in the process. The operation of the plant furthermore, required relevant man labor, mainly related to loading and unloading of the anaerobic cells.