The present study was conducted to eva‎luate the life cycle for energy-material production processes from the brown seaweed Nizimodinia zenardini (a species of algae in the Persian Gulf and the Sea of Oman) in order to identify the effects and processes with the most harmful environmental effects. The system boundary in this study included the stages of seaweed cultivation and maintenance, harvesting by barge ships, drying by steam extracted from natural gas, transportation to the entrance of biorefinery, seaweed processing, and product and waste/ residue production. Considering that the information about seaweed cultivation in Iran was not available in this study, the assumptions and values of an experimental cultivation site in Limfjorden, Denmark were used. Two different scenarios were investigated to eva‎luate the ecological potential of Nizimodinia zenardini seaweed. In the first scenario, which is the biofuel production scenario, the environmental potential of seaweed for bioethanol production was eva‎luated. In the second scenario, which is the process of producing valuable materials, the ecological potential of seaweed to produce valuable materials such as bioethanol, sodium alginate, protein, mannitol and biofertilizer was investigated. The functional unit in this study is the production of one kg of bioethanol, and all inputs and outputs of the system were calculated according to this value. Simapro software and existing Ecoinvent databases were used to check the life cycle assessment for both scenarios. The information related to the mass and energy balance related to this study was extracted from the laboratory and economic studies that have been done on this type of seaweed in the past. Life cycle inventory assessment was done with IMPACT 2002+. In the first scenario, the impact categories of damage to human health, the ecosystem, climate change, and resources consumption were 1.15×10-5 DALY, 1.58 PDF per square meter per year, 10.6 kg carbon dioxide equivalent, and 329 MJ, respectively. Also, the corresponding impacts of the second scenario were 4.93*10-6 DALY, 2.47 PDF per square meter per year, -12.3 kg carbon dioxide equivalent, and 733 MJ. By comparing the results of normalization, it can be concluded that the second scenario has better results than the first scenario in the two categories of human health damage and climate change. And in the category of ecosystem damage, they had almost the same results as the second scenario. But in the resource damage category, the results of the second scenario were twice as high as the results of the first scenario. It can be concluded that, in general, the second scenario had a better performance compared to the first scenario, and despite more effects in the resource damage category, it has provided more valuable alternative products than the first scenario.

كيخسرو كريمي

صفورا ميرمحمدصادقي

ارجمند مهرباني، محسن محمدي