Document Type : Research Paper
Authors
1 Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
2 Faculty Member in Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.
3 Department of Chemistry, Faculty of Science, University of Zanjan, Zanjan, Iran
Abstract
Keywords
Main Subjects
Evaluating the environmental impacts of eggplant production in hydroponic greenhouse: implementing a circular bioeconomy approach through composting and biochar
EXTENDED ABSTRACT
The recent global coronavirus outbreaks emphasize the crucial role of vitamins in boosting the human immune system. While fresh produce faces challenges in continuous availability, greenhouse cultivation, valued at $42.04 billion in 2023 and projected to reach $56.79 billion by 2028, offers a practical solution. However, traditional greenhouses raise sustainability concerns due to their heavy reliance on chemical pesticides. Hydroponic systems present an appealing alternative, reducing the need for chemicals. This research proposes an ecological-circular economic approach to manage agricultural waste in hydroponic systems, focusing on converting waste into compost or biochar. The approach aims for sustainability by utilizing renewable resources and fostering local development. The study, using the life cycle assessment (LCA) method, evaluates environmentaly the transition to a circular bioeconomy system in hydroponic eggplant cultivation, emphasizing the need for environmental compatibility before large-scale implementation.
This research focused on eggplant production under hydroponic systems, examining both conventional and circular bioeconomy approaches with a specific emphasis on compost and biochar production from eggplant green waste. The LCA method was employed to evaluate the environmental impacts of eggplant production under linear and circular bioeconomy systems. This approach offers a comprehensive assessment of the environmental effects throughout the entire life cycle of a product, from raw material extraction, through production and use, to disposal or recycling at the end of its life. The goal of this research as the first stege of an LCA was to investigate the environmental impacts of hydroponic eggplant production, transitioning from a linear economy to a circular bioeconomy under two pathways: compost and biochar. In the second stage, by documenting the environmental inputs and outputs throughout the eggplant life cycle, background and foreground information was collected from reliable sources. In the third stage, the environmental impact assessment was conducted using the ReCiPe method, revealing impacts at both midpoint and endpoint levels.
The environmental analysis of producing one kilogram of eggplant under hydroponic conditions reveals a significant carbon footprint increase of 2.37 kilograms of carbon dioxide, with 69% attributed to the production and consumption of natural gas. Additionally, the production of fertilizers and the use of steel in greenhouse structures introduce harmful substances like trichlorofluoromethane. Addressing these challenges necessitates the implementation of strategies to enhance production technology and substitute materials with lower environmental impact. According to the results, the production of one kilogram of hydroponic eggplant imposes health damages of 1.6×10-6 DALY on humans. Furthermore, in the ecisystems domain, the damage caused by producing one kilogram of hydroponic eggplant is equivalent to 1.08×10-8 species per year while in terms of resources, the estimated total damage cost is $0.261 per kilogram. Natural gas emerges as a significant contributor to these challenges, prompting recommendations for mitigating negative impacts through the adoption of sustainable energy sources and optimization of greenhouse heating systems. Furthermore, the benefits of eggplant production, adopting a circular bioeconomy approach and emphasizing compost production, are evident. This ecological-economic strategy results in reduced greenhouse gas emissions, ozone layer preservation, improved environmental and human health, reduced suspended particle production, and enhanced water and soil quality. A comparison between compost and biochar pathways reveals that compost production from green eggplant residues is more effective in mitigating negative impacts on human health, ecosystems, and resources. The results indicate that under the circular bioeconomy approach, especially the compost production pathway, there is a 16.6% reduction in health damages. Moreover, in the ecological realm, the compost production pathway contributes to biodiversity conservation with a 16% reduction compared to the biochar production pathway, demonstrating better performance. In the resource damage category, the compost production pathway from green eggplant residues leads to approximately a 16% reduction compared to conventional hydroponic eggplant production.
This study indicates that embracing circular bioeconomy approach, especially through compost production, proves effective in reducing environmental impacts of hydroponic eggplant. Comparing compost and biochar pathways underscores the superiority of compost production in mitigating negative impacts on health, ecosystems, and resources. A 16.6% reduction in health damages, ecosystems and resource damage reduction demonstrate the positive outcomes of transitioning from linear to circular bioeconomy practices through compost production vs. a 6% reduction through biochar production. In conclusion, adopting circular bioeconomy practices, particularly through compost utilization, provides a promising avenue for minimizing the environmental footprint of hydroponic eggplant cultivation, fostering sustainability and local development.
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