Ephrata Demissie and Shabbir H. Gheewala*
Abstract: Ethanol produced from different raw sources is used for a wide range of purposes, including as vehicle fuel. In Ethiopia, around 20 million liters of ethanol is expected to be produced from molasses every year by two dominant sugar factories (Metehara and Fincha). The main objective of this study is to assess the environmental effects of ethanol production from sugarcane molasses during the period 2016 to 2017. The functional unit is based on 1000 L-ethanol produced. Calculations were performed using the ReCiPe life cycle impact assessment method considering both midpoint and endpoint indicators. The result shows that the cultivation stage contributed the most to climate change (54.5%), photochemical oxidant formation (80%), and land use (99%) impact categories due to fertilizer production, cane burning and decomposition and application of fertilizers. On the other hand, ethanol production had a greatest contribution for resource depletion (63%), terrestrial acidification (92%), terrestrial ecotoxicity (99%), marine eutrophication (92%) and ozone depletion (84.4%) due to consumption of light fuel for ethanol plant and waste came from vinasses discharges into river. The endpoint indicators, however, showed that the cultivation stage was the major contributor to all the life cycle impacts from ethanol production. The outcome of this study is expected to be beneficial to the sugarcane sector and ethanol production, environmental and design engineers, and for academics and policymakers.
Keywords: Life Cycle Assessment (LCA), Sugar cane, Molasses, Ethanol.
Sudarat Rattana and Shabbir H. Gheewala*
Abstract: Due to the rapid increase in petroleum plastic consumption leading to severe waste problems and non-renewable resource depletion, bioplastics are an alternative option which can substitute petroleum plastic, serving as alternative renewable materials and expected to be more environmentally friendly. The goal of this study is to evaluate the environmental impacts in terms of global warming, fossil depletion, water depletion, land occupation, acidification, eutrophication, and toxicity for single-use carrier (shopping) bags produced from conventional plastic (HDPE) and bioplastic (PLA) and to find pros and cons of both products by applying the Life Cycle Assessment (LCA) tool. In addition, this study also focuses on the different waste management options. The results illustrate that petroleum plastic bags perform better than bioplastic bags in all categories and are quite similar in term of fossil depletion impact. The major stages contributing to the impacts of bioplastic bags are PLA production stage followed by the agricultural phase, particularly due to the higher resin requirement for bioplastic bag production as compared to plastic bags. Moreover, this study found that mechanical recycling is the most appropriate waste management option not just for petroleum plastic bags but also for bioplastic bags. However, there are other effects to the environment where bioplastics may be preferable to petroleum plastics, for instance, plastic waste accumulated in the deep marine environment and turning into microplastics affecting on the marine species, as well as persisting in the landfill for decades or centuries. Currently, the LCA study does not cover these impacts which are thus not mentioned in the study but will be beneficial to study further in the future.
Keywords: Life cycle assessment (LCA), Polylactic acid (PLA), High-density polyethylene (HDPE), Single use carrier bags, Sugarcane.
Robert H.B. Exell