Cement Manufacturers Association (CMA)

49 The Azonian Process: An Indigenous Novel Low-Cost Scalable Decarbonisation Pathway For The Indian Cement Industry Souryadeep Basak1*, Naqui Anwer1, Apoorva Mishra1, Aayushi Sharma2, Koshika Chhabra2 1. Department of Sustainable Engineering, TERI School of Advanced Studies, New Delhi, India 2. Department of Biotechnology, TERI School of Advanced Studies, New Delhi, India Corresponding Author: souryadeep.basak@terisas.ac.in Abstract Carbon capture, utilisation, and storage has received attention lately as a measure to mitigate climate change. However, the artificial routes of carbon capture are economically inadequate to be scaled up in the global South. This paper presents a novel approach to capture atmospheric carbon via enhanced cultivation of the aquatic fern azolla, which has one of the lowest biomass doubling times among photosynthetic species. Due to the fern’s ability to also capture atmospheric nitrogen through its symbiosis with an endophytic cyanobacteria, the harvested azolla can be used as a bio-fertiliser, reducing the demand for nitrogenous fertilisers like urea and di-ammonium phosphate. This could reduce the emissions associated with the production and use of such synthetic fertilisers. Besides capturing carbon dioxide through a natural process, this practice could also reduce the dependence of small and marginal farmers on expensive synthetic fertilisers, making the agricultural community more resilient to the impacts of climate change. The applicability of this novel decarbonisation pathway has been explored vis-à-vis the hard-to-abate Indian cement industry A preliminary financial analysis, complete with a discounted cash flow analysis and sensitivity analysis has also been presented to communicate the financial viability of this carbon capture technology. Keywords: carbon capture, utilisation and storage (CCUS), net-zero, cement, decarbonisation Introduction Azolla is an aquatic fern with very high growth rates, achieving a biomass doubling time of 2 to 5 days under optimal conditions 1. Apart from the high growth rates, azolla has a symbiotic relationship with an endophytic cyanobacteria Anabaena azollae which can fix atmospheric nitrogen 2,3. This characteristic enables the growth of azolla in nitrogen deficient conditions. Azolla can be used as a nutritional supplement for fish, poultry and dairy livestock 4. Azolla based biofuels are another end use alternative through the process of transesterification 5. Since both the aforementioned end uses release a portion of the captured CO 2 back to the atmosphere , this study focusses on the use of azolla as a bio-fertiliser 6, offsetting the demand for nitrogenous fertilisers like urea and di-ammonium phosphate, which are responsible for significant greenhouse gas emissions 7 . The high growth rate of azolla can be leveraged to sequester atmospheric carbon dioxide (CO 2 ) through the process of photosynthesis. One mathematical modelling study has hypothesised 1,018,023 km2 of effective azolla cultivation under their assumed growth equations would be equivalent to sequestering the annual net anthropogenic CO2 emissions into the atmosphere 8 .