An exciting collaboration is taking place between Trinity College Dublin’s TERRAFORM group and a research team at University College Dublin working on the “Crushed returned concrete as a soil amendment for carbon capture” project. Co-funded by iCRAG and Silicate, the project aims to investigate the potential of concrete application on agricultural soils as a negative emissions technology. A team of botanists and geologists from two leading Irish universities have joined forces to provide a holistic understanding of the potential of enhanced weathering to capture carbon, as well as any possible benefits for crops.
The project draws on silicate weathering, an ancient process that plays an important role in the Earth’s long-term carbon cycle, capturing CO2 from the atmosphere and helping regulate the Earth’s climate over millions of years. Cations produced during rock weathering react with CO2 from the atmosphere and the reaction products are eventually stored deep in the ocean as carbonates.
The ancient silicate weathering process inspired the exploration of enhanced weathering as a negative emissions technology. The practice aims to accelerate weathering reactions in order to remove CO2 from the atmosphere and reduce the effects of global warming. It commonly involves crushing silicate rocks followed by application onto agricultural soils, where it has the added benefit of weathered rock acting as a fertilizer by providing nutrients to crops. This project is unique in that it aims to investigate the possibility of using an otherwise waste industrial product, concrete, as the reactant in this process, further streamlining the sustainability of enhanced weathering as a practice.
Pilot studies are in full swing on fields of barley and oat located in Co. Wexford. Dr Ruadhán MaGee and Leo Hickey, based at UCD, study the CO2 removal potential under field conditions. Terraform members, Dr Christos Chondrogiannis and Katie O’Dea investigate the impact of concrete application on crop physiology and yields.
Possible positive results yield multiple benefits including; 1) Enhanced weathering as a carbon negative emission technique, 2) Alternate use of crushed concrete, a waste by-product of construction industry, 3) use of rocks as a crop soil fertilizer.