Is Excavated Soil and Rock a Waste? Sintering Utilization Says No

Urban construction, especially the ongoing large-scale expansion and utilization of underground space, has resulted in massive excavated soil and rock (ESR) from buildings and subways. A novel solution suggests sintering utilization is a feasible method to recycle solid waste to construction products from the perspective of technology, environment, and policy through qualitative and quantitative methods in Shenzhen, China.

They published their study on 19 May 2022, in Circular Economy. (DOI 10.1016/j.cec.2022.100007)

This study discusses the feasibility of ESR environmental-friendly sintering technology and aims to explore the utilization of sintering from the technical point of view, environmental protection restrictions, and governmental policy levels. Specifically, the case object of this study is ESR generated in Shenzhen.

First, the technical evaluation aims to determine whether the soil conditions of ESR meet the criteria of relevant standards and technical sintering utilization specifications. The investigation of ESR samples in Shenzhen reveals that the soil types in each administrative region of the city are complex and diverse, and the ESR of high-content clay produced by the existing construction project in Shenzhen (2020) is estimated to be 37.3%, which can be recycled as the sintering raw materials. On this basis, we can estimate the entire amount of high-content clay that can be used as sintering raw materials in Shenzhen is close to 27 million m³. If some fired brick and tile plants operated in Shenzhen under the encouragement of competent authorities, using 27 million m³ of clay-rich ESR to sintered products instead of traditional disposal will save nearly 270 million yuan of disposal cost.

Researchers of this study also collected the actual emission data of some representative fired brick plants of ESR (or co-combustion) as sintering raw materials in China, and the actual air emission concentration of domestic factories can meet the “Emission Standard of Air Pollutants for Brick and Tile Industry (GB-29620-2013)”, which showed that there was no implementation obstacle from the environmental perspective of sintering ESR.

Finally, at the policy level, mainly from the perspective of national and provincial policies and systems, the sintered brick industry belongs to the encouraged industry. It is feasible to promote ESR sintering utilization at the national and municipal policy levels.

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About Circular Economy

Circular Economy is an international journal serving as a sharing and communication platform for novel contributions and outcomes on innovative techniques, systematic analysis, and policy tools of global, regional, national, local, and industrial park’s waste management system to improve the reduce, reuse, recycle, and disposal of waste in a sustainable way.

Circular Economy is a fully open access journal. It is co-published by Tsinghua University Press and Elsevier, and academically supported by the School of Environment, Tsinghua University, and the Circular Economy Branch, Chinese Society for Environmental Sciences. At its discretion, Tsinghua University Press will pay the Open Access Fee for all published papers from 2022 to 2024.

About Tsinghua University Press

Established in 1980, belonging to Tsinghua University, Tsinghua University Press (TUP) is a leading comprehensive higher education and professional publisher in China. Committed to building a top-level global cultural brand, after 41 years of development, TUP has established an outstanding managerial system and enterprise structure, and delivered multimedia and multi-dimensional publications covering books, audio, video, electronic products, journals and digital publications. In addition, TUP actively carries out its strategic transformation from educational publishing to content development and service for teaching & learning and was named First-class National Publisher for achieving remarkable results.