Francesco da Borso

Microbiological aspects of humid husk composting.

The feasibility of composting as disposal practice of husk mixed with olive mill wastewaters (OMW) was studied in the present research. The process was investigated with regards to some reliable and easy to be determined microbial activity parameters such as the ATP content, the activity of a pool of enzymes and the viable counts, keeping in mind the well known bias of this last technique. Two different composting technologies were compared: static pile and reactor by studying the cured composts obtained. Among the bioindicators tested, the composting process trend was described better by the ATP content and the activity of some enzymes. In fact, the ATP content showed an increase during the thermophilic phase in both the pile and the reactor, and decreased at the end of the process, it was also higher in the bioreactor‐pile technology than in the pile. With regard to the enzymatic activity, with the reactor technology experiment, two peaks were evidenced in the thermophilic phase and during the curing phase in pile, and a drop during the transfer of material from the reactor to the pile. The quality of the cured product obtained using the reactor technology has been evaluated considering phytoxicity and hygienic features: the stabilised compost resulted to have neither phytoxical effect, nor faecal indicator contaminants.

Dry anaerobic digestion of cow manure and agricultural products in a full-scale plant: efficiency and comparison with wet fermentation.

For years, anaerobic digestion processes have been implemented for the management of organic wastes, agricultural residues, and animal manure. Wet anaerobic digestion still represents the most common technology, while dry fermentation, dedicated to the treatment of solid inputs (TS>20%) can be considered as an emerging technology, not in terms of technological maturity, but of diffusion. The first agricultural dry anaerobic digestion plant constructed in Italy was monitored from the start-up, for over a year. The plant was fed with manure and agricultural products, such as corn silage, triticale, ryegrass, alfalfa, and straw. Three Combined Heat and Power units, for a total installed power of 910kWe, converted biogas into thermal and electric energy. The monitoring included the determination of quality and quantity of input feedstocks, of digestate (including recirculation rate), of leachate, biogas quality (CH4, CO2, H2S), biogas yield, energy production, labor requirement for loading, and unloading operations. The results of the monitoring were compared to performance data obtained in several full scale wet digestion plants. The dry fermentation plant revealed a start-up phase that lasted several months, during which the average power resulted in 641kWe (70.4% of nominal power), and the last period the power resulted in 788kWe (86.6% of installed power). Improving the balance of the input, the dry fermentation process demonstrated biogas yields similar to wet anaerobic digestion, congruent to the energy potential of the biomasses used in the process. Furthermore, the operation of the plant required significant man labor, mainly related to loading and unloading of the anaerobic cells.

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.

Anaerobic Digestion of Swine Manure in Conventional and Hybrid Pilot Scale Plants: Performance and Gaseous Emissions Reduction

This study aims to present the results of a series of experimental tests performed with pilot scale digesters operating with swine manure: two digesters were conventional high load, completely mixed type, while the third digester was a hybrid type, with a fixed bed up-flow section.

Ventilation Control of Pig-Houses During Winter Period

Abstract The aim of this article is to present some experience on the field of ventilation control of pig-houses dining a winter period and some information about the mathematical simulation of indoor air conditions in ventilated buildings with different equipment used for breeding of pigs. The simulation model accounts for a large number of parameters including category and characteristics of animals, structure of building, local climatic data, ventilation rate, heating and heat recovery systems.