Field Study on CO2 Sequestration through Mineral Carbonation and Enhanced Weathering using Waste Clays

This study investigates the potential of waste clays for CO2 sequestration through mineral carbonation and enhanced weathering in Northeast England. Light Brown Clay and Reddish Clay, provided by Scott Bros Ltd, were tested under field conditions for 12 months. The trial pits featured three configurations: clays tested alone, integrated with compost as topsoil, and thoroughly mixed with compost. Compost addition improved soil structure and moisture retention while enhancing microbial activity. Results demonstrated significant increases in carbonate content across all treatments. Reddish Clay mixed with compost showed the highest performance, with carbonate content increasing from 17.45 g/kg to 22.56 g/kg. Consistent declines in pH, indicative of carbonation reactions, were accompanied by notable improvements in soil compaction and moisture retention. Soil temperature variations, ranging from 16°C in summer to 3°C in winter, influenced reaction kinetics, with warmer conditions accelerating carbonation.
These findings highlight the synergistic role of waste clays with and without compost in enhancing CO2 sequestration. The study underscores the effectiveness of using waste clays and compost as sustainable materials for carbon capture and soil improvement, particularly in urban and industrial settings.