Use of biochar waste in carbon capture and reduced emissions

This project will explore the potential of biochar for use as a climate-responsible, high-performance, pavement material.

According to Transport Emissions: Driving down car pollution in cities, transport contributes 17% of Greenhouse Gas (GHG) emissions in Western Australia (WA). While vehicle emissions are an obvious source of GHG emissions, the construction of transport infrastructure also contributes. New pavement materials offer the potential not only to improve pavement performance but to contribute to achieving WA’s aspirational target of net zero emissions by 2050, through reuse, carbon storage and reduced emissions.

Biochar is the product of pyrolysis, which is the process of heating biomass to a relative high temperature (500 °C, for example) without oxygen. It is a lightweight black solid that locks carbon in a chemically stable form and can endure in soil for thousands of years. It has a long history of being used to increase soil fertility and agricultural productivity but there has been a growing interest in its role in carbon capture and storage because of its stability.

Furthermore, recent literature suggests that biochar can improve asphalt’s performance against the effects of aging, deformation, and high temperature. To harness the carbon sequestration potentials, this research will investigate:

1. the application of biochar as a filler material in asphalt pavements; and
2. the combination of biochar and limestone dust to reduce or even replace the anti-stripping agent – hydrated lime (the production of which generates a large amount of greenhouse gases into the atmosphere).

Participants

• Department of Transport (WA)
• University of Western Australia

Project background

Over 75% of natural resources are allocated and consumed in cities, where over 70% of global waste production is also generated (Zaman and Lehmann, 2013). With approximately half of the GHG emissions associated with material handling and use (IRP, 2019), there is a clear need to transform linear value chains and preserve material value to achieve Net Zero at the city scale (UNEP, 2021).

Circular economy strategies are becoming increasingly more popular in mitigating waste production and helping to maintain materials and resources in use, effectively reducing the need to extract virgin materials in production processes (Kirchherr et al., 2017). This equally applies to resources, such as concrete, metals, glass, electronics, plastics, fossil fuels, and biomass at an industry and household level.

Problematically, however, creating closed material loops at a product or industry level alone does not ensure environmental sustainability (Harris et al., 2021), highlighting the importance of a systems-wide approach at a city or regional level that goes beyond waste management strategies (Schandl et al., 2020). Such an approach must monitor and integrate indicators with a clear understanding of the circularity mechanism concerning economic activity and environmental performance (Lieder and Rashid, 2016; Pauliuk, 2018).

Together with Local and Regional Councils, State departments, and industry partners, this project will further enhance our understanding of circularity in Western Australia (WA) with the ultimate aim of providing a key performance indicator framework within a digital circular monitor (suggested working title: Western Australian Tool for Circular Horizons – WATCH) for effectively monitoring and driving circular outcomes.

Such comprehensive tools are critical in understanding urban metabolism and supporting cross-sector collaboration towards enhanced resource efficiency and environmental performance. These innovative tools and processes will provide governments, industry, communities, and any interested stakeholders with the conceptual and empirical backbone to support circular planning and decision-making related to waste minimisation and effective circular applications within WA (D’amato and Korhonen, 2021). This project will position WA as a global leader in integrating circular economic and Net Zero approaches within a digital monitoring framework.
The purpose of the longer-term project is to map and monitor the flow of materials from extraction to end-of-use and support the identification of key opportunities towards greater circularity and Net Zero emissions for WA cities. The research will create tangible methods and tools for WA cities to measure, monitor and report on enhanced material flows (including narrowing, slowing, cycling, and regenerating) and assess progress towards decoupling raw material use and environmental impacts from economic activity and societal needs.

Through local and state government demonstrations, the project will inform resource strategies (including enhanced resource efficiency, closing supply chains, product lifetime extension, and residual waste management) and enable scale-up plans at the city and regional scale.

These objectives align with WA’s Waste Avoidance and Resource Recovery Strategy 2030 and its key objectives such as waste avoidance, recovery and environmental protection, and addresses many of the identified knowledge and information gaps (Government of Western Australia – Waste Authority, 2019). More broadly, the project supports the WA Climate Policy’s commitment to a low carbon transition (Government of Western Australia – Department of Water and Environmental Regulation, 2020L), The National Circular Economy Roadmap (2022), National Waste Policy (2018) and Action Plan (2019) and to the UN’s Sustainable Development Goals (United Nations, 2015): namely, Goal 11 and 12.

Project objectives

This project concerns the first step in the process of developing such a digital circular economy monitoring framework for WA. This stage 1 project will provide a high-level overview and understanding of the materials footprint and socioeconomic metabolism of Greater Perth within the wider WA context.

Stage 1 will measure the materials footprint linked to final consumption in Greater Perth, quantifying the resource inflow and waste outflow and related energy use and greenhouse gas (GHG) emissions.

Building on the material footprint, localised stock and flow accounts of actual material and energy use within the administrative boundaries of Greater Perth will be prepared, providing a high-level overview, and understanding of the socioeconomic metabolism of Greater Perth, and the wider WA economy.

The project objectives are to:

• determine the state of play in circular economy systems research and policy internationally and locally;
• quantify and visualise the resource inflow and waste outflow linked to final consumption within Greater Perth and the related energy use and greenhouse gas (GHG) emissions;
• estimate, map and visualise the material stocks and flows within the administrative boundaries of Greater Perth; and
• recommend further stages and dissemination will conclude Stage 1.

Please note …

This page will be a living record of this project. As it matures, hits milestones, etc., we’ll continue to add information, links, images, interviews and more. Watch this space!

REFERENCES

Bolan, N.S., Thangarajan, R., Seshadri, B., Jena, U., Das, K.C., Wang, H. and Naidu, R. (2013) “Landfills as a biorefinery to produce biomass and capture biogas”, Bioresource Technology, 135, 578-587
Lehmann, J., Gaunt, J. and Rondon, M. (2006) “Bio-char sequestration in terrestrial ecosystems – a review”, Mitigation and Adaptation Strategies for Global Change, 11, 403-427
Zhao, S., Huang, B., Ye, X.P., Shu, X. and Jia, X. (2014) “Utilizing bio-char as a bio-modifier for asphalt cement: A sustainable application of bio-fuel by-product”, Fuel, 133(2014), 52-62
Celoglu, M.E., Yilmaz, M., Kok, B.V. and Yalcin, E. (2016) “Effects of various biochars on the high temperature performance of bituminous binder”, 6th Euraphalt & Eurobitume Congress, 1-3 June 2016, Prague, Czech Republic, (DOI): dx.doi.org/10.14311/EE.2016.232
Galetakis, M. and Soultana, A. (2016) “A review on the utilisation of quarry and ornamental stone industry fine by-products in the construction sector”, Construction and Building Materials, 102 (2016), 769-781.
Antonio, J., Bastos, G., Almeida, J., Tadeu, A., Marques, B., Marques, A., Armesto, J., and Patino-Barbeito, F. (2021) “Influence of different dosages of limestone dust and charcoal on the properties of light weight cement composites”, Journal of Materials in Civil Engineering, ASCE, 33(10), 04021271, DOI: 10.1061/(ASCE)MT.1943- 5533.0003891.
Downie, A., Van Zwieten, L. (2013). “Biochar: A Coproduct to Bioenergy from Slow-Pyrolysis Technology”, Chapter 8 In: Lee, J. (eds) Advanced Biofuels and Bioproducts. Springer, New York, NY.
Lehmann, J., Kuzyakov, Y., Pan, G. and Ok, Y.S. (2015) “Biochars and the plant-soil interface”, Plant Soil, 395 (2015), 1-5,