Poultry litter valorization to energy

Historically manure has found utilization as fertilizer in agriculture because it contributes to the fertility of the soil by adding organic matter and nutrients, such as nitrogen, phosphorus and potassium. However, the current European Directive 91/676 drastically reduces the application of this material as fertilizer due to its high nitrate content. Therefore, identification of alternative eco-friendly disposal routes with potential financial benefits has become necessary, and the energetic valorization of these biomasses is particularly promising. Poultry litter represents one of the more challenging bio-fuel feedstocks for energy generation, being easy to handle and showing a composition that potentially assures a high energy content and the production of a byproduct (ash) with good fertilizing properties. In this paper an evaluation of the technical and economic feasibility of the energy conversion technologies usable to recover both the potential energy and fertilizer properties of poultry litter was provided. The focus was posed on the poultry farms of North-East Italy, where more than half of the national poultry production is concentrated. The preliminary cost analysis suggests that energy production from poultry litter is actually economically viable in the case of large off-site plants only by means of anaerobic digestion, while in the case of small plants operating in situ the gasification process appears the most convenient option.