Comparative life cycle assessment of fired brick production in Thailand

Fired bricks are an essential construction material in Thailand where the majority of fired brick kilns use rice husk as feedstock. Given the increasing demand of rice husk from other industries, alternative feedstocks are needed for future fired brick production. This life cycle assessment (LCA) study investigates the environmental burden of Thai brick production using different biomass types. Three biomass fuels for fired brick production were compared: cane leaves, rice straw, and rice husk. Both the attributional and consequential modeling approaches were applied. Separated inventories were compiled using different databases: ecoinvent v. 3 and the Thai National Life Cycle Inventory (TH-LCI). Overall, this study includes a total of nine scenarios, for which characterized results were calculated using the Stepwise method. Differences in biomass scenario, modeling approach, and database used were tested via analysis of variance using four distinct fired brick production plants as replications. Overall, using cane leaves and rice straw gives lower impacts than using rice husk. The largest burden for cane leaves and rice straw scenarios comes from the burning process, while using electricity and using fertilizers for rice cultivation were the most contributors for rice husk scenario. However, different modeling approaches yield mostly significantly different results and the consequential results were lower than the attributional ones. Regarding database choice in attributional modeling approach, results were lower when using TH-LCI compared with ecoinvent. Using cane leaves and rice straw as fuels in fired brick production are better scenarios than using rice husk. Nevertheless, factors related to season, size, and collection effort should be considered in the large-scale use of these biomasses. For database choice, ecoinvent is currently recommended over TH-LCI despite the higher geographical representativeness of the latter.