"The accumulation of waste has been a nationwide issue in recent years, involving challenges such as incinerator bottom ash from municipal waste, steel slag from industrial steel mills, and reclaimed asphalt from road construction," explained Shih Jing-Lan, Section Chief of the Construction Management Section, Public Works Department, Taoyuan City Government, highlighting the environmental problems arising from the handling and disposal of industrial and municipal waste.
Taiwan produces approximately 3 million metric tons of steel slag, 5 million metric tons of reclaimed asphalt pavement, 1 million metric tons of incinerator bottom ash, and 150,000 metric tons of waste tires annually. The lack of proper disposal facilities for these materials has led to significant problems, including forced reductions in steel mill production, stalled public infrastructure projects, and disruptions in municipal waste recycling. These issues have caused severe economic losses and greatly affected daily life. To address these challenges and align with sustainable economic development and net-zero emissions policies, the Taoyuan City Government has designated road paving projects as demonstration initiatives. The government has developed applications for recycled materials such as "incinerator bottom ash aggregate," "steel slag aggregate," "reclaimed asphalt pavement (RAP)," and "waste tire rubber granules." Additionally, it has planned to introduce a GIS (Geographic Information System) to manage road paving projects utilizing recycled materials throughout the city. This systematic approach aims to promote the use of recycled materials in road construction, establish a model for best practices, and advance the circular economy.
Addressing the Challenge of Incinerator Bottom Ash Management
Taiwan primarily relies on incineration, supplemented by landfilling, to manage waste. Incineration processes and high-temperature treatment produce a significant amount of incinerator bottom ash. According to statistics from the Environmental Protection Administration, the annual output of incinerator bottom ash in Taiwan has been approximately 800,000 to 1 million metric tons in recent years. Given Taiwan's limited land availability and rising environmental awareness, sustainable development has become a pressing trend. Utilizing incinerator bottom ash for recycling not only reduces waste but also achieves the goals of sustainable resource use and a circular economy, addressing one of the key challenges faced by the government today.
"Taoyuan City generates approximately 60,000 metric tons of incinerator bottom ash annually. We coordinate with the Department of Environmental Protection to first cure the ash for three months. After the curing process is completed and inspected by the Department of Environmental Protection, the ash is transported to recycling plants where it is processed into construction materials for use in public infrastructure projects," explained Yang Chao-Fu, Section Chief of the Construction Management Section, Public Works Department, Taoyuan City Government.
Circular Economy to Protect the Ecosystem
Taiwan's annual demand for gravel exceeds 75 million tons, making it the second most consumed resource after water. Extracting sea sand disrupts seabed stability, while river sand mining alters river and coastal ecosystems, leading to ecological disasters such as river flooding and coastal erosion.
"Road construction projects often generate waste from milled asphalt, which presents disposal challenges. To address this, we proactively utilize these materials as recycled resources in engineering projects. This approach reduces the need for raw material extraction while efficiently repurposing waste," shared Section Chief Yang Chao-Fu of the Public Works Section.
The Taoyuan City Government has implemented initiatives to recycle industrial waste from steel mills into asphalt concrete materials, reuse milled asphalt in road sublayers, and incorporate rubber powder from waste tires into road surfaces. These efforts aim to achieve zero waste through recycling, significantly reducing the need for river and sea sand excavation. By embracing circular economy practices, Taoyuan safeguards the ecosystem and ensures a sustainable living environment for future generations.
Building Consensus Through Communication and Advocacy
"When we first started promoting the policy for using recycled materials, both suppliers and the public were skeptical. During the process, we addressed their concerns about safety and quality through educational campaigns and demonstration projects. Additionally, when suppliers began adopting recycled materials, they faced challenges such as resource allocation issues. For example, using Material A might displace Material B. To mitigate these concerns, we provided alternative solutions and strategies," explained Section Chief Shih Ching-Lan and Subsection Chief Yang Chao-Fu, discussing how they overcame skepticism and gained support from suppliers and the public.
The Taoyuan City Government aims not only to expand the use of recycled materials but also to establish a robust framework by revising construction standards, developing user manuals, and implementing the "Taoyuan City Guidelines for the Use of Recycled Aggregates and Green Building Materials Certification in Public Works." Furthermore, the government provides support to asphalt mixing plants and recycling institutions for transformation and upgrading, thereby creating a comprehensive recycling industry chain. This approach effectively reduces waste aggregates, promotes resource regeneration, and enhances the Circular Economy Recycled Materials Management Platform to optimize resource control, flow management, and recycling goals. These efforts resolve challenges faced by the industry and construction sectors, ensuring that contractors and the general public can confidently accept and utilize recycled materials.
Sustainable and Low-Carbon City
"Taiwan is a small island with limited natural resources. Natural aggregate extraction is highly susceptible to weather conditions, and its prices fluctuate significantly. To stabilize material supply and reduce natural resource extraction, adopting recycled aggregates is an inevitable solution. Using recycled aggregates not only saves project costs but also reduces energy consumption and carbon emissions, protects the ecological environment, and preserves limited resources for future generations. This approach aligns with the nation's goals for sustainable development," stated Section Chief Shih Ching-Lan and Subsection Chief Yang Chao-Fu. They highlighted that Taoyuan City's recycled material utilization rate has reached 40%, the highest among all counties and cities in Taiwan. By enhancing resource sustainability, reducing construction costs, and addressing industrial challenges, Taoyuan City aims to steadily advance toward becoming a sustainable and low-carbon city.