Uncovering the energy-carbon-water footprint of waste rubber recycling: Integrated environmental and economic perspectives

The commitment to waste management has gained increasing momentum as global waste generation continues to skyrocket and threaten the environment. However, detailed assessments and clear insights remain absent to address the global waste utilization conundrum. This study evaluated the impact-oriented energy, carbon, and water (ECW) footprints of three typical scenarios for a waste recycling activity (i.e., waste rubber recycling) from environmental and economic dimensions, and explored key factors, nexus characteristics, and optimization measures. Results indicated that the rubber powder as an asphalt modifier scenario had a 93% greater environmental impact and 87% higher economic cost compared with the pyrolysis and reclaimed rubber production scenarios. Key processes, such as direct processes, electricity generation, and transportation, were identified as the major contributors to the ECW footprints, with the internal costs of raw materials, equipment, and taxes coupled with the external costs of human health dominating the economic impact. The nexus analysis results highlighted the urgent need to optimize the energy system for waste rubber recycling. Greening the production process revealed the benefits, with natural additives mitigating 85% of the environmental burden and 97% of the external costs compared with conventional additives. Industrial green microgrids, clean energy generation, proximity waste management, and electrified transportation were explored to foster sustainable optimization of waste rubber recycling systems. Moreover, a joint tax-subsidy mechanism for rubber production-recycling systems can stimulate recycling-oriented product design and increase the motivation to recycle waste rubber.

Automated summary

The commitment to waste management is growing in importance due to the increasing global waste generation and its threat to the environment. However, there is a lack of detailed assessments and insights on how to address the global waste utilization challenge. This study evaluated the impact of three waste recycling scenarios for waste rubber recycling from environmental and economic perspectives, identified key factors and nexus characteristics, and explored optimization measures. The results showed that the rubber powder as an asphalt modifier scenario had a higher environmental impact and economic cost compared to the pyrolysis and reclaimed rubber production scenarios. Key processes such as direct processes, electricity generation, and transportation were identified as major contributors to the environmental, carbon, and water footprints, while raw materials, equipment, and human health costs dominated the economic impact. The study highlighted the urgent need to optimize the energy system for waste rubber recycling and proposed various measures such as greening the production process and introducing a tax-subsidy mechanism to stimulate recycling-oriented product design.