CO2 SEQUESTIONAL

8/16/2019 CO2 SEQUESTIONAL

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Carbon Sequestration by Aquatic Microalgaein India—A State of the Art Review

R. Saravanane1*, T. Sundararajan

2 and N. Madhivanan

3 1,2Professor, Environmental Engineering Lab, Department of Civil Engineering,

Pondicherry Engineering College, Pondicherry–14, India3 Junior Research Fellow (JRF), Environmental Engineering Lab, Department of Civil

Engineering, Pondicherry Engineering College, Pondicherry–14, IndiaE-mail: *[email protected]

ABSTRACT

Carbon dioxide sequestration by aquatic micro algae appears to be the most promising,

environmental friendly and cost effective means of reducing carbon dioxide emission inthe energy sector. Carbon sequestering–capturing and storing carbon emitted from theglobal energy system by such photo-bioreactors could be a major tool for reducingatmospheric CO 2 emissions. Such carbon sequestration technologies could be ideallyincorporated and best applied in connection with large-scale energy conversion plantssuch as coal power plants and oil refineries. Carbon sequestration offers the possibilityfor new industrial applications such as the production of hydrogen, together withelectricity, from fossil fuels. This paper provides a state of he art review on this subject.

Keywords : Carbondioxde, Microalgae, Bubbling Reactor, Photo Bio-reactor

INTRODUCTIONCarbon dioxide is a naturally occurring chemical compound composed of twooxygen atoms each covalently double bonded to a single atom. It is a gas atstandard temperature and pressure and exists in the earth’s atmosphere in thisstate, as a trace gas at a concentration of 0.039 per cent by volume. As part ofthe carbon cycle, plants, algae and cyanobacteria use light energy tophotosynthesize carbohydrate from carbon dioxide and water, with oxygenproduced as a waste product. Carbon dioxide produced by combustion of coal

or hydrocarbons. CO 2 is also found in lakes, at depth under the sea andcommingled with oil and gas deposits.

The environmental effects of carbon dioxide are of significance interest.Carbon dioxide is an important greenhouse gas, absorbing heat radiation fromEarth’s surface which otherwise would have left the atmosphere. Burning ofcarbon-based fuels since the industrial evolution has rapidly increasedconcentrations of atmospheric carbon dioxide increasing the rate of globalwarming and causing anthropogenic climate change. CO 2 emissions areexpected to increase at an annual rate of 3%. The potential effects of globalwarming on India vary from the submergence of low lying islands and coastallands to the melting of glaciers in the Indian Himalayas, threatening thevolumetric flow rate many of important rivers of India and south Asia.

Records show that 0.6 ºC increase in global average temperature over thepast century mainly due to increase in atmospheric CO 2. The best scientific

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322 Green India: Strategic Knowledge for Combating Climate Change: Prospects & Challenges

MATERIALS AND METHODS

A small experimental setup (Fig. 1.) could be viable solution to study the effect

of CO2 sequestration.

Fig. 1: Sequestration of CO 2

Aquaculture systems involving microalgae production and wastewatertreatment (e.g., of amino acids, enzymes or food industries wastewaters)seems to be quite promising for microalgae growth combined with biologicalcleaning. This allows nutrition of microalgae by using organic compounds(nitrogen and phosphorous) available in some manufactures wastewater, notcontaining heavy metals and radioisotopes. Additionally, microalgae canmitigate the effects of effluent and industrial sources of nitrogenous wasteas those originating from treatment of fish aquaculture and at the sametime contributing to biodiversity. Moreover, removing nitrogen and carbonfrom water, microalgae can help reduce the eutrophication in theaquatic environment.

Mode of cultivation of algae:

Algae can be cultivated in two ways:

Open pond system.

Closed photo bioreactors.

A comparison of open and closed large scale culture system for micro algae.

Culture System for Algae Closed System (PBRs) Open Systems (Ponds)Contamination control Easy DifficultContamination risk Reduced HighSterility Easy NoneProcess control Easy DifficultSpecies control Easy NoneMixing Uniform Very poorOperating regime Batch/ Semi-continuous Batch/ Semi-continuous Area/ Volume ratio High (20.200/m) Low (5-10/m)Population density High LowInvestment High PoorOperation costs High LowCapital/ operating costs High LowLow utilization efficiency High PoorTemperature control More uniform temperature Difficult

Productivity 3-5 times more LowWater losses Depend upon cooling design EqualEvaporation on growth medium Low HighGas transfer control High LowCO2 losses Depend on pH, alakalinity etc Same.

Thermal Powerplant

Pre-Treatmentof flue gas

Co2 Algal Pond


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Carbon Sequestration by Aquatic Microalgae in India—A State of the Art Review 323

There are different types of photo bioreactors available in the market:

Vertical tubular photo bioreactor.

Flat panel photo bioreactor. Horizontal tubular photo bioreactor.

Helical type photo bioreactor.

Stirred tank photo bioreactor.

Hybrid type photo bioreactor.

CONCLUSIONS

CO2 sequestration is very essential to prevent earth from global warming. As CO2 plays a major role in green house effect. We must take care of increasingatmospheric CO 2 level. The most economic way of reducing CO 2 is by Biologicalmethod by using Microalgae. The suitable method of growing microalgae isdiscussd above. Microalgae not only plays vital role in CO 2 reduction it alsoused as alternative source for fuel. Microalgae on further processing usedas Biodiesel.

Algae Biomass to Biodiesel

Biodiesel is a mixture of mono alkyl esters of long chain fatty acids (FAME)derived from a renewable lipid feedstock such as algal oil. After the extractionprocess, the resulting product algal oil can be converted into biodiesel througha process called trans esterification. Trans-esterfication is a chemical reactionbetween triglycerides and alcohol in the presence of a catalyst to mono-estersthat are termed as biodiesel.

Algal biodiesel has several advantages over petroleum diesel in that:

• It is derived from biomass and therefore is renewable, biodegradableand quasi-carbon neutral under sustainable production.

• It is non-toxic and contains reduced levels of particulates, carbonmonoxide, soot, hydrocarbons and SOx.

REFERENCES

[1] Booras, G.S., Smelser, S.C. (1991). An engineering and economic evaluation of CO 2 removal fromfossil-fuel fired power plants. Energy, 1295–1305.

[2] Barbosa, M.J., Janssssen, M., Ham, N., Tramper, J., Wijffels, R.H. (2003). Microalgae cultivation inair-lift reactors: Modelling biomass yield and growth rate as a function of mixing frequency.Bitechnol. Bioeng., 82(2), 170–179.

[3] Chiu, S.Y., Kao, C.Y., Chen, C.H., Kuan, T.C., Ong, S.C., Lin, C.S. (2008). Redcution of CO 2 by a highdensity culture of chlorella sp. in a semi continuous Photo bioreactor. Bio resource Technology, 99,3389–3396.

[4] De Morais, M.G., Coasta, J.A.V. (2007). Isolation and selection of microalgae from coal firedthermoelectric power plant for bio fixation of carbon dioxide. Bio-energy research, 48(7), 2169–73.


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[5] Iqbal, M., Grey, D., Sarkissian, F.S., Fowler, M.W. (1993). A flat-sided photo bioreactor forcontinuous culturing microalgae. Aquaculture Engineering, 12, 183–190.

[6] Maeda, K., Owada, M., Kimura, N., Omata, K., Karube, I. (1995). CO 2 fixation from the fluegas on coal-fired thermal power plant by Microalgae. Energy conversion and management, 36(69),717–20.

[7] Nurdogan, Y., Ostwald, W.J. (1996). Tube settling rate of high-rate Pond algae. Water scienceTechnology, 33, 229–41.

[8] Tsukahara, K., Sawayama, S. (2005). Liquid fuel production using microalgae. Journal of the JapanPetroleum Institute, 48(5), 251–9.

[9] Wang, B., Li, Y., Wu, N., Lan, C.Q. (2008). CO 2 bio-mitigation using microalgae. Applied Microbiologyand Biotechnology, 79(5), 707–18.

[10] Xu, Y., Isom, L., Hanna, M.A. (2010). Adding value to carbondioxide from ethanol fermentations.Bioresource and Technology, 31, 523–532.

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