• Energy Research
• 6. Clean water close

The slow pyrolysis process of poultry litter was investigated using different experimental and analytical techniques. A fixed bed reactor was used for the simulation of the slow pyrolysis process up to a constant temperature (400–800 °C) under nitrogen flow. Yields of the different product fractions were determined. On-line FTIR techniques were used to detect the most significant compounds in the evolved gas (carbon dioxide, carbon monoxide and methane). GC–MS results allowed the identification of the more important categories of compounds in the liquid condensate (phenols, fatty acids, sterols, N-containing compounds). The fate of nitrogen and sulphur, present in relevant amounts in the original substrate, was investigated: sulphur remains mostly in char at any investigated temperature, while nitrogen is split among the different products, slightly increasing its transfer to the gas phase only at higher pyrolysis temperatures. The energy transfer from the original biomass substrate to the different product fractions was also investigated. The fraction of biomass energy transferred to non-condensable gases raises with pyrolysis temperature and was estimated to be able to thermally sustain the process at 550 °C. The results obtained shed some light on the potential use of the slow pyrolysis process for sanitation and waste-to-energy valorization of poultry litter.

Abstract Removal of acid pollutants (HCl and SO2) is an important stage in waste incineration flue gas cleaning. Several technological options for acid gas neutralisation are currently available in order to comply with the increasingly stringent emission limit values and the choice of the best solution for a specific plant should be based on the economic and environmental considerations implied in the concept of Best Available Technique. The present study analyses and compares state-of-the-art dry, semi-dry and wet process configurations for acid gas removal in waste-to-energy plants. The performance of five representative process schemes was analysed: the streams associated with acid gas emission control were quantified via mass and energy balances and a life cycle perspective was applied in order to evaluate the inputs and outputs of the supply and disposal chains. The analysis pinpoints the key issues in terms of environmental and economic performance of the presented alternatives. Benefits and limits of the alternative technologies are discussed in view of different waste composition. The energy penalty associated with flue gas reheat appears to be the main environmental drawback of wet methods, while the main contribution to the environmental footprint of dry methods is given by the production of solid reactants. Multi-stage treatment systems systematically show lower environmental impacts than the single stage counterparts, but their cost-effectiveness is limited by the disposal cost for the generated solid residues. The provided insights can contribute to a more effective implementation of the strategies of circular economy and cleaner production in the operation of a waste-to-energy plant.

Background, Aim and Scope The increasing concern about environment protection and a broader awareness of the sustainable development issues cause more and more attention to be given to the environmental impacts of products through the different phases of their life cycle. Foods are definitely among the products whose overall environmental performance can be effectively investigated resorting to LCA. A LCA case study was performed in order to detect and quantify the environmental impacts deriving from the life cycle of a lager beer produced by an Italian small brewery, investigating and comparing two packaging options: beer in 20 L returnable stainless steel kegs and beer in 33 cL one way glass bottles.