Kaohsiung's CLSM Product Earns Carbon Label, Advancing Low-Carbon Management of Incineration Bottom Ash Recycling

The Kaohsiung City Environmental Protection Bureau has announced that it has assisted a local ready-mix concrete manufacturer in obtaining a carbon label for its 'Controlled Low-Strength Material (CLSM)' product made from incineration bottom ash. This achievement signifies that recycled construction materials have advanced from resource reuse to a new stage of scientific carbon footprint management.

The Bureau explained today that it guided Fengho Company, a ready-mix concrete producer located in Daliao District, to apply for the carbon label using CLSM produced by replacing natural aggregates with recycled bottom ash aggregates. The product received certification from the Environmental Protection Administration in June, becoming the first CLSM product in Kaohsiung to earn the carbon label.

In a press release, the Kaohsiung Environmental Protection Bureau emphasized that recycled bottom ash aggregate is a key component of CLSM. By selecting CLSM as the subject for carbon footprint calculation, the goal is to scientifically and quantitatively demonstrate the carbon reduction outcomes of the city's bottom ash recycling policy.

The CLSM product has undergone third-party verification in accordance with the international standard 'ISO 14067' for carbon footprint assessment. The results show that each cubic meter of CLSM emits 194 kilograms of carbon dioxide equivalent (kg CO2e).

The Bureau noted that engineering units can now compare the carbon footprint of CLSM with other construction materials, enabling the environmental benefits of recycled materials to be quantified, disclosed, and traced. This data will serve as a reference for future green procurement and low-carbon construction projects.

Kaohsiung operates four incineration plants, generating approximately 170,000 metric tons of incineration bottom ash annually. The Environmental Protection Bureau explained that bottom ash was previously treated as waste, but after proper processing, it can now be converted into recycled aggregates used in road construction, site backfilling, and CLSM for public infrastructure projects.

The Bureau added that in the previous year, Kaohsiung achieved a 100% bottom ash treatment rate and a 97% recycling rate for recycled aggregates. A complete ecological chain has been established, covering source material production, midstream quality control, and end-product utilization.

Zhang Ruihui, Director of the Kaohsiung City Environmental Protection Bureau, stated that the Bureau has been progressively supporting industries such as the Kaohsiung MRT, hotel operators, and ready-mix concrete producers. The goal is to help various sectors build comprehensive databases to guide consumers and downstream industries in taking concrete decarbonization actions. By analyzing carbon emissions, suitable reduction strategies can be identified, contributing collectively to the vision of a sustainable city. (Edited by Chang Ya-ching) 1150622