• Energy Research

Purpose In Italy, composting olive mill waste has become a common practice, since it mitigates the environmental problems associated with spreading the waste on land. Compost can be used to prepare growth media for plant nursery cultivation as a substitute for peat, a non-renewable resource whose extraction has long raised environmental concerns. Here, we investigate two common composting procedures--open windrow and static-pile in gas-permeable bags--and compare them to evaluate their environmental impact. Methods We perform a cradle-to-grave life cycle assessment (LCA) in accordance with ISO 14040 and 14044. The LCA considers carbon storage in the soil after 100 years, fugitive greenhouse gas (GHG) emissions, and the impacts avoided by substituting for peat. We use cumulative energy demand, global warming potential (GWP), acidification potential, and eutrophication potential indicators in a contribution analysis and explore how the re-use of olive pits for energy production and reduction of commercial fertilizers improves the environmental balance. We also present a scenario analysis that indicates how parameter fluctuations affect the results. Results and discussion Our study shows that peat's impacts can be significantly reduced from 1162.3 to 96.3 kg CO2-eq/Mg for open windrow compost or 43.1 kg CO2-eq/Mg for static-pile compost in gas-permeable bags. For static-pile composting, the lack of volatile organic compound and ammonia emissions and the detection of oxygen concentrations above 12% vol. suggest fully aerobic conditions. Fugitive greenhouse gas emissions were the most important contributions to the GWP. In the contribution analysis for static-pile composting, the avoidance of compost spreading and the carbon storage effect (due to compost usage) contributed 54% of the overall impacts to GWP and between 21 and 45% to the other indicators. Conclusions This LCA study illustrates how horticulturists can improve their resource management practices by recycling olive mill waste materials. Proper management of composting unit aeration can reduce fugitive GHG emissions.

Abstract This paper presents the results of a detailed LCA study of a low-energy consumption building (thermal energy for heating equal to 11 kWh/m2 year) located in Perugia, Italy, according to European ISO 14040 and 14044. The building matches the criteria of environmental sustainability and bio-architecture, complying with the “PassivHaus” standard. All life cycle phases were included in the research: acquisition and production of materials, on-site construction and use/maintenance, demolition and material disposal (100% landfilling and demolition with waste recycling). A life span of 70 years was considered. The research was therefore focused on cradle-to-grave life, based on data collected by authors, integrated with data from the literature. In particular the study was carried out to analyze: the benefits due to the use of recycled materials, a solar PV (during the utilization years) and the final demolition of the building. The LCA modeling was performed using the SimaPro software application, connected to the ecoinvent database. The results show that applying energy saving measures (highly insulated building envelope and passive-house standard, solar PV, waste recycling and recycled products in pre-production phase) could significantly decrease the impact of modern dwellings, with the consciousness that new ways of building do not always provide a positive environmental outcome.