Concrete waste as a source of calcium and alkalinity for coccolithophore cultivation: an experimental test of carbon dioxide removal and sequestration

Hydrated lime and ground waste concrete increased calcite production in coccolithophore Chrysotila sp cultures, with lime yielding 3.6-fold higher rates (4.5 vs. 1.2 mg L-1 d-1) over 26 days.

• Why it matters: Coccolithophore calcification can release CO2, so CDR depends on supplying calcium together with alkalinity rather than calcium alone.
• What they did: In a 26-day factorial batch culture experiment, pH, nitrate, and dissolved calcium were monitored, calcite was quantified by thermogravimetric analysis, and carbonate-system calculations estimated CO2 uptake capacity changes.
• The result: Lime and concrete raised pH significantly without differing algal growth rate inferred from nitrate drawdown; added alkalinity increased equilibrium CO2 uptake capacity by ca. 3.4 mmol kg-1, offsetting CO2 released by calcification.

AI summary of the abstract · may contain errors · not medical advice · read the paper.