Luiz Kulay

Environmental and energy assessment of the substitution of chemical fertilizers for industrial wastes of ethanol production in sugarcane cultivation in Brazil

PurposeVinasse and filter cake are residues of bioethanol processing that are used to be recycled as fertilizers in sugarcane plantation. Studies related to the environmental dimension on this practice are concerned only with the effects on water and soil. The present study examines the systemic effects of replacing chemical fertilizers with vinasse and filter cake on the environmental performance of ethanol, via life cycle assessment (LCA).MethodsThe analysis was carried out by comparing various scenarios structured from two control variables: crop management techniques (manual and mechanized harvesting) and source of nutrients (for supplying the nutritional needs of sugarcane crops): chemical fertilizers, chemical fertilizers + vinasse, and chemical fertilizer + vinasse + filter cake. Impact assessment was carried out in terms of primary energy demand, climate change, terrestrial acidification, freshwater eutrophication, human toxicity, and terrestrial ecotoxicity. LCA has been applied according to both attributional and consequential perspectives. Moreover, a sensitivity analysis was performed in order to verify the effects of the varying amounts of nitrogen (N), phosphorus (P), and potassium (K) in the composition of vinasse on the results obtained for the impact profile.Results and discussionFrom the attributional LCA perspective, the most expressive contributions regarding primary energy demand occurred in terms of depletion of non-renewable fossils. Replacing chemical fertilizers with vinasse and filter cake was beneficial for the environmental performance of ethanol as it reduces climate change, terrestrial acidification, and human toxicity impacts and sustains freshwater eutrophication and terrestrial ecotoxicity unaltered in relation to scenarios using only fertilizers. In terms of consequential LCA, ethanol’s environmental performance is influenced by the inclusion of the production of calcium fluorite to compensate the hexafluorosilicic acid deficit occurring in conjunction to the decrease of phosphate fertilizer and is compensated by the benefits provided by the general reduced consumption of chemical fertilizers for most of the impact categories. The exception occurred for primary energy demand.ConclusionsThe reuse of residues from bioethanol production—vinasse and filter cake—as primary nutrient suppliers for the cultivation of sugarcane instead of chemical fertilizers is a valid practice that improves the environmental performance of ethanol, even if it is analyzed under a consequential LCA perspective. The transport of these inputs to the field must be managed, however, in order to minimize primary energy demand and climate change impacts.

Hydropower Life-Cycle Inventories: Methodological Considerations and Results Based on a Brazilian Experience

Hydropower studies are among the least discussed themes concerning energy systems life-cycle assessments (LCA). This scarcity may be related both to the relevance of this energy source in only a small group of countries and to the difficulty in obtaining the necessary data to conduct those evaluations. The present chapter gives some useful insights regarding specifically the construction of hydropower life-cycle inventories (LCI), aiming to help LCA practitioners involved with environmental evaluation of this source of electricity. Starting with a brief review of the available studies, methodological considerations are given, separated by each LCI methodological step. These recommendations are illustrated with a case study of Itaipu Hydroelectric Power Plant, the largest energy plant in operation worldwide, leading to conclusions and recommendations for further studies. With the present chapter, the authors hope not only to guide, but encourage the conduction of new hydropower plants LCIs, in order to improve the actual LCA databases used for renewable energy sources comparison.

Life Cycle Inventory of Physic Nut Biodiesel: Comparison Between the Manual and Mechanised Agricultural Production Systems Practiced in Brazil

The physic nut (Jatropha curcas L.) is an oleaginous species recently introduced into Brazil for energy purposes. The technological framework for the development of the physic nut biodiesel productive chain in Brazil is still being set up. Two production systems are in practice at the agricultural level, the small scale manual system and the medium scale mechanised system. The objective of the present research was to assess the environmental performance of these two production systems by elaborating life-cycle inventories (LCIs) using a cradle-togate approach. The main environmental aspects of these LCIs are the synthetic fertilisers, pesticides, land-use changes and its emissions and the occupation of the land. Making use of the residues from the agroindustrial physic nut chain and the use of biological pest control methods could improve the environmental performance of these systems.

Verifying the effectiveness of environmental performance improvement actions in the chain of production of an agrochemical produced in Brazil

PurposeA Brazilian agrochemical company agreed to conduct an initiative to further evaluate the environmental impact caused by its product SC50. This agrochemical is obtained from thiophanate-methyl, an active ingredient produced in Brazil as well as in Japan, where another industrial plant of the same corporation is located. The initiative evaluated the environmental performance of the SC50 life cycle so as to provide the company’s private management with information to influence stakeholders in the sector.MethodsThe working method comprised five steps. Step 1 established the impact profile associated to the SC50 life cycle. The diagnosis was obtained by LCA from a ‘cradle-to-grave’ approach. Step 2 identified the stages causing significant environmental impacts throughout the entire life cycle. In Step 3, improvement actions were proposed in order to mitigate, reduce, or even minimize the effects detected. Step 4 comprised the modeling, in which specific scenarios and their environmental impacts were analyzed. The synergistic effect was checked by successive additions of improvement actions, characterizing each scenario. Step 5 analyzed the results, comparing impact profiles of each scenario with the original diagnosis (as a baseline scenario) and verifying the individual effect of each action.Results and discussionThe results indicate relevant contributions of the dispersion from the SC50 life cycle in terms of global warming, terrestrial ecotoxicity, human toxicity, and eutrophication. Regarding to the manufacture, the use of diesel has great influence in the impacts of SC50, and its performance as eutrophication is conditioned to the low efficiency of the wastewater treatment. While the company decided not to implement improvements in the dispersion stage fearing market losses, five alternatives based on cleaner production principles were proposed to improve performance: to review the instrumentation systems in the plant, to adjust wastewater treatment, to stop importing thiophanate-methyl from Japan, to install an energy cogeneration system, and to substitute renewable glycerin with a fossil counterpart. All scenarios led to improvements from baseline.ConclusionsThe use of LCA determined the impact profile associated to SC50 in soybean pest control. Because of strategic reasons, the company decided not to propose improvements in the most significant stage of this life cycle. Among the improvements, we highlight the replacement of imported thiophanate-methyl by a Brazilian equivalent and the installation of a combined cycle for energy recovery. For both these cases, however, the appropriate organizational measures must be taken before implementation.