Life Cycle Assessment of electricity production in Italy from anaerobic co-digestion of pig slurry and energy crops

This study aims to evaluate the environmental consequences and energy requirements of a biogas production system and its further conversion into bioenergy by means of the Life Cycle Assessment (LCA) methodology. To do so, an Italian biogas plant operating with pig slurry and two energy crops (maize and triticale silages) as feedstock was assessed in detail in order to identify the environmental hotspots. The environmental pro\ufb01le was estimated through six impact categories: abiotic depletion potential (ADP), acidi\ufb01cation potential (AP), eutrophication potential (EP), global warming potential (GWP), ozone layer depletion potential (ODP) and photochemical oxidation potential (POFP). An energy analysis related to the cumulative non-renewable fossil and nuclear energy demand (CED) was also performed, considering this indicator as an additional impact category. According to the results, the biomass production subsystem was identi\ufb01ed as the main environmental key issue in terms of ADP, AP, EP, ODP and CED, with contributions ranging from 26% to 61% of the total impact. Regarding ADP, ODP and CED, these results are mainly related with diesel requirements in agricultural machinery, derived combustion emissions and mineral fertilizers production. Concerning AP and EP the production \ufb01eld emissions derived from fertilizers application was observed as the main contributor. Concerning GWP, this step presents an environmental credit due to the uptake of CO2 during crop growth, which contributes to offset the GHG emissions. The bioenergy production plant signi\ufb01- cantly contributes to the environmental impact in categories such as GWP (43%) and POFP (59%), mostly related with emissions produced in the gas engine and biogas losses. Emissions derived from digestate storage contribute to AP (52%) and EP (41%). The use of the digestate as an organic fertilizer has a bene\ufb01cial role because this action avoids the production and use of mineral fertilizers. A sensitivity analysis was also conducted to assess the in\ufb02uence of variations in important parameters of biogas systems. The environmental pro\ufb01le of the biogas system turned out to be highly dependent on the selection of system boundaries and the allocation method. To sum up, this study aims to assess the environmental performance of a biogas technology available not only in Italy but also in other European countries. The environmental analysis of the process under study highlights the environmental bene\ufb01ts of the co-digestion processes, which not only produces biofuel but also reduces the disposal of solid wastes and produces digestate, with special value in the fertilization of agricultural soil

Assuring the sustainable production of biogas from anaerobic mono-digestion

This study aims to analyse the potential environmental benefits and impacts associated to the anaerobic mono-digestion of two different substrates (pig slurry and maize silage). The Life Cycle Assessment methodology was applied in two full-scale Italian biogas plants (Plant A - pig slurry and Plant B - maize silage) in order to calculate the environmental profile of both systems with the aim of identifying the most suitable alternative from an environmental point of view. The study also includes credits due to avoided processes such as electricity production from the grid and mineral fertilisation as well as the conventional management of pig slurry regarding Plant A. The main outcomes show the importance of the feedstock composition on the environmental performance of these systems. While the assessment of Plant A ended up in environmental benefits in all impact categories as a consequence of credits related to replaced processes, its capacity for bioenergy production was limited. On the contrary, the use of maize silage as substrate provided a larger production capacity but it was also associated to negative environmental impacts. In this system, the cultivation of maize showed up as the largest responsible of the environmental impacts, specifically due to diesel fuel consumption in agricultural activities as well as on-site emissions linked to the application of fertilisers. A sensitivity analysis proved that the environmental profile of these bioenergy systems could be improved through surplus heat use as well as technological improvements such as the replacement of the traditional dehumidification unit by a chiller. \ua9 2014 Elsevier Ltd. All rights reserved

Environmental and sustainability evaluation of livestock waste management practices in Cyprus

The aim of this study was to compare the environmental performance and sustainability of different management options for livestock waste in Cyprus. The two most common practices in the country, i.e. the use of anaerobic lagoons and conventional biogas plants, were compared with the innovative scheme developed in the LiveWaste project (LIFE12 ENV/CY/000544), which aims not only to produce bioenergy, but also to treat the digestate for nutrient recovery and water reuse. The Life Cycle Assessment (LCA) methodology was combined with the Analytic Hierarchy Process (AHP) to compare the performance of these alternatives. Four relevant indicators were selected for each dimension of sustainability (environmental, social and economic). The results of the evaluations showed that anaerobic lagoons are not an appropriate option for the sustainable management of livestock waste due to environmental (e.g. climate change, acidification and eutrophication) and social impacts (e.g. noise exposure, visual impact and risk perception for human health). The most important strengths and weaknesses of anaerobic treatment with and without digestate treatment were identified. Compared to conventional anaerobic digestion where digestate is directly applied as an organic fertiliser, the technology proposed in the project entails higher technological complexity due to nitrogen removal and phosphorus recovery. The rise in chemical and electricity requirements increased the impacts on some indicators, such as climate change and operational cost (emissions of greenhouse gases and operation costs were around 50% higher), while reduced impacts in others due to proper nutrient management, as acidification and eutrophication impacts (which were 10 and almost two times lower, respectively). For the specific Cypriot conditions, where the overapplication of nutrients leads to pollution of water bodies, the innovative treatment scheme with higher technological development presents an interesting approach. Nevertheless, the treatment of the digestate should be analysed taking into account the specific characteristics of each scenario

Environmental assessment of bioenergy production through suitable wastewater and waste management

Environmental assessment of bioenergy production through suitable wastewater and waste managemen

Environmental assessment of farm-scaled anaerobic co-digestion for bioenergy production

The aim of this study was to assess the environmental profile of a bioenergy system based on a co-digestion plant using maize silage and pig slurry as substrates. All the processes involved in the production of bioenergy as well as the avoided processes accrued from the biogas production system were evaluated. The results evidenced the environmental importance of the cultivation step and the environmental credits associated to the avoided processes.In addition, this plant was compared with two different plants that digest both substrates separately. The results revealed the environmental benefits of the utilisation of pig slurry due to the absence of environmental burdens associated with its production as well as credits provided when avoiding its conventional management. The results also presented the environmental drawbacks of the utilisation of maize silage due to the environmental burdens related with its production. Accordingly, the anaerobic mono-digestion of maize silage achieved the worst results. The co-digestion of both substrates was ranked in an intermediate position.Additionally, three possible digestate management options were assessed. The results showed the beneficial effect of digestate application as an organic fertiliser, principally on account of environmental credits due to avoided mineral fertilisation. However, digestate application involves important acidifying and eutrophicating emissions

Environmental Assessment of Organic Waste and Domestic Wastewater Management in Decentralised Communities

Environmental Assessment of Organic Waste and Domestic Wastewater Management in Decentralised Communitie