Document Type : Research Paper
Authors
1 Department of Agricultural Machinery Engineering, College of Agriculture and Natural Resources, University of Tehran,, Iran
2 Department of Agricultural Machinery Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
3 Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
4 Department of Agricultural Machinery, Faculty of Agricultural Engineering and Technology, College of Agriculture and Natural Resources, Tehran University
Abstract
Keywords
Main Subjects
Evaluation of the environmental impacts of two pathways for utilizing chicken meat production waste in Guilan Province
EXTENDED ABSTRACT
Chicken meat not only can address the essential amino acids and protein requirements of humans but also as a cost-effective dietary choice. However, the rapid growth of the chicken industry due to its reasonable price and good quality has given rise to serious challenges pertaining to environmental sustainability and escalated energy consumption. In response to this challenge, the concept of circular bioeconomy that can be implemented by biorefineries is taken into consideration, aiming to transform chicken waste into added-value products, thereby mitigating the environmental impact. This study assesses the environmental impacts of chicken meat production based on this approach under two various pathways by life cycle assessment.
Primary data is sourced from a prominent collection representing one the Iran's most extensive chicken production and distribution networks in the Guilan province during 2022-2023. To implement a circular bioeconomy approach for chicken meat production two various pathways are proposed. Pathway 1 encompasses all processes within chicken farms and slaughterhouses. Additionally, chicken feathers obtained during the slaughterhouse stage were employed for sound insulation generation in this biorefinery. In contrast, Pathway 2 focuses on chicken meat and sound insulation production, as well as utilizing chicken fat waste from the slaughtering phase to produce biodiesel through esterification and transesterification processes. A life cycle assessment tool is used to assess the environmental impacts of chicken meat production under the mentioned pathways. The system boundaries are limited to meat production in farms and slaughterhouses along with the waste valorization phase and one ton of chicken meat as the functional unit is considered. The life cycle inventory is collected directly (face-to-face interview) and indirectly from the literature and EcoInvent database. The life cycle impact assessment is done by the ReCiPe method among available options due to its capacity to identify environmental impact at both midpoint and endpoint levels by the employment of SimaPro software. The study also weighted the environmental impacts to obtain a single score that helps to a better comparison and a more correct decision.
Pathway 1 results in higher carbon emissions and ozone layer depletion due to electricity usage, while pathway 2, focusing on diverse bioproducts, reduces these impacts significantly. It also decreases other impact categories such as acidification, eutrophication, and land occupation. The findings highlight Pathway 2 is a practical and sustainable approach to improve the midpoint impact categories while promoting system efficiency and managing waste effectively. From the point of view of endpoint level, Pathway 1 leads to damages of 6.83E-03 DALY to human health, 6.81E-05 species.yr to ecosystems, and $101 to resources. Pathway 2 reduces damages by 23.26% in human health damage, 24.48% in ecosystem damage, and 17.76% in resource depletion. Weighting assigns more importance to categories with greater environmental impact. Under Pathway 1, each ton of chicken meat production results in 321.49 Pt, with human health damage contributing the most (200.23 Pt). Pathway 2, producing biodiesel, glycerol, and sound insulation, reduces overall impacts by 21.92%, showing improvements in human health (23.26%), ecosystem quality (24.48%), and resource depletion (17.76%). A sensitivity analysis is also done to identify effective factors in each damage category in both pathways. The results indicate that direct emissions, natural gas, and electricity play a key role in human health and ecosystem damage categories. For the resources damage category, optimal fossil fuel consumption significantly reduces impacts.
The study highlights that chicken meat production and its waste valorization under Pathway 2 leads to a decrease of 23.26% in human health, 24.48% in ecosystems, and 17.76% in resources compared to Pathway 1. Accordingly, variation in production for systems based on a circular bioeconomy approach can be proposed. Since chicken farms are trying to obtain more sustainability, this finding helps them to improve efficiency and decrease damages waste as well as produce a greener production for the future.