Alessandra Fusi

Environmental assessment of two different crop systems in terms of biomethane potential production.

The interest in renewable energy sources has gained great importance in Europe due to the need to reduce fossil energy consumption and greenhouse gas emissions, as required by the Renewable Energy Directive (RED) of the European Parliament. The production of energy from energy crops appears to be consistent with RED. The environmental impact related to this kind of energy primarily originates from crop cultivation. This research aimed to evaluate the environmental impact of different crop systems for biomass production: single and double crop. The environmental performances of maize and maize plus wheat were assessed from a life cycle perspective. Two alternative scenarios considering different yields, crop management, and climatic conditions, were also addressed. One normal cubic metre of potential methane was chosen as a functional unit. Methane potential production data were obtained through lab experimental tests. For both of the crop systems, the factors that have the greatest influence on the overall environmental burden are: fertilizer emissions, diesel fuel emissions, diesel fuel production, and pesticide production. Notwithstanding the greater level of methane potential production, the double crop system appears to have the worse environmental performance with respect to its single crop counterpart. This result is due to the bigger quantity of inputs needed for the double crop system. Therefore, the greater amount of biomass (silage) obtained through the double crop system is less than proportional to the environmental burden that results from the bigger quantity of inputs requested for double crop.

Environmental profile of paddy rice cultivation with different straw management.

Italy is the most important European country in terms of paddy rice production. North Italian districts such as Vercelli, Pavia, Novara, and Milano are known as some of the worlds most advanced rice cultivation sites. In 2013 Italian rice cultivation represented about 50% of all European rice production by area, and paddy fields extended for over 216,000 ha. Cultivation of rice involves different agricultural activities which have environmental impacts mainly due to fossil fuels and agrochemical requirements as well as the methane emission associated with the fermentation of organic material in the flooded rice fields. In order to assess the environmental consequences of rice production in the District of Vercelli, the cultivation practices most frequently carried out were inventoried and evaluated. The general approach of this study was not only to gather the inventory data for rice production and quantify their environmental impacts, but also to identify the key environmental factors where special attention must be paid. Life Cycle Assessment methodology was applied in this study from a cradle-to-farm gate perspective. The environmental profile was analyzed in terms of seven different impact categories: climate change, ozone depletion, human toxicity, terrestrial acidification, freshwater eutrophication, marine eutrophication, and fossil depletion. Regarding straw management, two different scenarios (burial into the soil of the straw versus harvesting) were compared. The analysis showed that the environmental impact was mainly due to field emissions, the fuel consumption needed for the mechanization of field operations, and the drying of the paddy rice. The comparison between the two scenarios highlighted that the collection of the straw improves the environmental performance of rice production except that for freshwater eutrophication. To improve the environmental performance of rice production, solutions to save fossil fuel and reduce the emissions from fertilizers (leaching, volatilization) as well as methane emissions should be implemented.

Mitigation strategies in the agro-food sector: the anaerobic digestion of tomato purée by-products. An Italian case study.

Tomato processing involves a significant production of residues, mainly constituted by discarded tomatoes, skins, seeds and pulp. Often, these residues are not valorized and represent an added cost for manufacturing companies because of disposal processes, with environmental issues due to the difficult management. The exploitation of these residual materials results complex as their availability is mainly concentrated in few months. A possible solution is the production of biogas employed in a Combine Heat and Power engine for energy production, in line with the 2020 targets of European Union in terms of promotion of energy from renewable resources and greenhouse gas emission reduction. The tomato by-product utilization for energy production as a strategy to reduce the environmental load of tomato purée was evaluated by means of Life Cycle Assessment. Two scenarios were considered: Baseline Scenario - tomato by-products are sent back to the tomato fields as organic fertilizers; Alternative Scenario - tomato by-products are employed in a nearby biogas plant for energy production. Methane production of tomato by-products was assessed by means of specific laboratory tests. The comparison between the two scenarios highlighted reductions for all the impact categories with the Alternative Scenario. The most important reductions are related to particulate matter (-5.3%), climate change (-6.4%) and ozone depletion (-13.4%). Although small, the reduction of the environmental impact cannot be neglected; for example for climate change, the anaerobic digestion of by-products allows a saving of GHG emissions that, over the whole year, is equal to 1.567 tons of CO2 eq. The results of this study could be up-scaled to the food industries with high heat demand producing considerable amounts of fermentable by-products employable as feedstock for biogas production.

Life Cycle Assessment in the Cereal and Derived Products Sector

This chapter discusses the application of life cycle assessment methodologies to rice, wheat, corn and some of their derived products. Cereal product systems are vital for the production of commodities of worldwide importance that entail particular environmental hot spots originating from their widespread use and from their particular nature. It is thus important for tools such as life cycle assessment (LCA) to be tailored to such cereal systems in order to be used as a means of identifying the negative environmental effects of cereal products and highlighting possible pathways to overall environmental improvement in such systems. Following a brief introduction to the cereal sector and supply chain, this chapter reviews some of the current cereal-based life cycle thinking literature, with a particular emphasis on LCA. Next, an analysis of the LCA methodological issues emerging from the literature review is carried out. The following section of the chapter discusses some practices and approaches that should be considered when performing cereal-based LCAs in order to achieve the best possible results. Conclusions are drawn in the final part of the chapter and some indications are given of the main hot spots in the cereal supply chain.

Life Cycle Environmental Impacts of Electricity from Biogas Produced by Anaerobic Digestion

The aim of this study was to evaluate life cycle environmental impacts associated with the generation of electricity from biogas produced by the anaerobic digestion (AD) of agricultural products and waste. Five real plants in Italy were considered, using maize silage, slurry, and tomato waste as feedstocks and cogenerating electricity and heat; the latter is not utilized. The results suggest that maize silage and the operation of anaerobic digesters, including open storage of digestate, are the main contributors to the impacts of biogas electricity. The system that uses animal slurry is the best option, except for the marine and terrestrial ecotoxicity. The results also suggest that it is environmentally better to have smaller plants using slurry and waste rather than bigger installations, which require maize silage to operate efficiently. Electricity from biogas is environmentally more sustainable than grid electricity for seven out of 11 impacts considered. However, in comparison with natural gas, biogas electricity is worse for seven out of 11 impacts. It also has mostly higher impacts than other renewables, with a few exceptions, notably solar photovoltaics. Thus, for the AD systems and mesophilic operating conditions considered in this study, biogas electricity can help reduce greenhouse gas (GHG) emissions relative to a fossil-intensive electricity mix; however, some other impacts increase. If mitigation of climate change is the main aim, other renewables have a greater potential to reduce GHG emissions. If, in addition to this, other impacts are considered, then hydro, wind, and geothermal power are better alternatives to biogas electricity. However, utilization of heat would improve significantly its environmental sustainability, particularly global warming potential, summer smog, and the depletion of abiotic resources and the ozone layer. Further improvements can be achieved by banning open digestate storage to prevent methane emissions and regulating digestate spreading onto land to minimize emissions of ammonia and related environmental impacts.