CO2 sequestration and flue gas mitigation

CO2 sequestration and flue gas mitigation ( Click here for News item in Deccan Chronicle)

Microalgae, a diverse group of fast growing prokaryotic and eukaryotic photosynthetic microorganisms, have the capacity to fix CO2 from atmosphere and industrial flue gas streams or utilizing inorganic carbonate salts (e.g., Na2CO4 and NaHCO4) to produce high quality biofuels via biophotosynthesis. They are the most promising bio-species for combined CO2 mitigation and renewable biofuel production due to their high photosynthetic efficiency. It was also suggested that microalgal CO2 mitigation and biofuel production could be combined with waste heat utilization, wastewater treatment and/or production of novel bioproducts to further enhance the economical feasibility and environmental sustainability of micro algal CO2 mitigation and biofuel production using microalgae. 

The advantages of algae based technology: The microalgae for CO2-mitigation strategy offers numerous advantages. Firstly, microalgae have much higher growth rates and CO2 fixation abilities compared to conventional forestry, agricultural, and aquatic plants (Borowitzka 1999; Chisti 2007; Li et al. 2008). Secondly, it could completely recycle CO2  because carbon dioxide is converted into the chemical energy via photo-synthesis, which can be converted to fuels using existing technologies (Demirbas 2004). In comparison, the chemical reaction-based CO2 mitigation approaches, as discussed above, have disposal problems because both the captured CO2 and the wasted absorbents need to be disposed of (Bonenfant et al. 2003; Yeh et al. 2001). Thirdly, as discussed previously, chemical reaction-based CO2mitiga-tion approaches are energy-consuming and costly processes (Lin et al. 2003;Resniketal.2004), and the only economical incentive for CO2mitigation using the chemical reaction-based approach is the CO2credits to be generated under the Kyoto Protocol. On the other hand, CO2 bio-mitigation using microalgae could be made profitable from the production of biofuels and other novel bioproducts. Finally, the microalgal CO2bio-mitigation could be made more economically cost-effective and environmentally sustainable, especially when it is combined with other processes such as wastewater treatment.

TECHNOLOGY: Dr V Sivasubramanian has developed algae based technology to mitigate flue gas and produce valuable algal biomass. Culture collection at PERC has some of the robust freshwater and marine micro algal species which can be very effectively employed in largescale mitigation at various industries. The technology developed by Dr V Sivasubramanian is being implemented at pilot scale and largescale flue gas mitigation in some of the industries. Dr V Sivasubramanian is collaborating with Shree Cement, Rajasthan and ONGC, New Delhi to perfect this technology.


Industrial projects

Dr V Sivasubramanian and his team has implemented algae based treatment technology in industries in India and abroad. pH correction, sludge reduction/removal, BOD and COD reduction have been achieved through Phycoremediation MORE