Ozonation

Conventional methods of water treatment don’t remove some pollutants persistent at lower concentrations in water. Xylem (2012) referred pollutants at lower concentrations in drinking water as micro pollutants and explained persistence problem or bio accumulation of micro pollutants and endocrine effects or hormonal disruption of humans and animals. Reproductive effects on certain kinds of fish, decrease in fertility in humans and animals and developments of certain types of cancer are possible consequences of Endocrine Disruptive Compound (EDCs) in drinking water (Xylem, 2012).

Ozonation process is effective pollutant removal treatment process where ozone reacts with organic pollutants and dissolved organic carbon (DOC). Ozone is highly corrosive and toxic colourless gas and powerful oxidant capable of oxidising organic and inorganic compounds in water (EPA, 1999). Ozone is formed by combining an oxygen atom with oxygen molecule (O2). Ozone reacts with substrate or organic and inorganic compounds by direct oxidation and oxidation of compounds by hydroxyl free radicals (EPA, 1999).

Ozone attacks bacterial membrane either through the glycoproteins or glycolipids or through certain amino acids (Giese and Christensen, 1953 cited in EPA, 1999; Goldstein and McDoriagh, 1975 cited in EPA, 1999; Scott and Lesher, 1963 cited in EPA, 1999) and ozone reacts with nuclear material affecting pyrines and pyrimidine in nucleic acids.

Ozone acts on viral capsid to inactivate viruses and high concentration of ozone dissociates the capsid completely (EPA, 1999). Ozone inactivates RNA and DNA of the viruses. Protein capsid is affected by ozone attack which releases nucleic acid and inactivates DNA (Sproul et al., 1982 cited in EPA, 1999).

Ozonation is employed in bleaching process for pulp bleaching in pulp and paper industry, drinking water treatment such as improvement of flocculation, de coloration, taste/odour removal, iron/manganese removal, disinfection, algae removal and elimination of persistent substances, waste water treatment processes such as elimination of tensides, phenols, COD, process water such as cooling water, swimming pools and product polishing such as chemical modification of food and shelf-life improvement of food [Xylem, 2012; Sato & Saito, 2013].

Ozonation can be applied in water treatment process to remove bacteria, viruses, organic and inorganic pollutants and hazardous chemicals, controls colour, taste and odours and do not require chemicals as ozone is generated on-site [Xylem, 2012]. Ozonation process is also applied in the treatment of waste water contaminating milk and physico- chemically treated municipal wastewater r (Absi et al., n.d.).

References

Absi, F., Gamache, F., Genr, R., Leichti, P., and Nicell, J. (n.d.) Pilot Plant Investigation of Ozone Disinfection of Physico-Chemically Treated Municipal Waste Water. [Online] Available at http://www.ozonia.com/media [Accessed on 09 November 2013].

Environment Protection Agency (EPA) (1999) EPA Guideline Manual Alternative Disinfectants and Oxidants. [Online] Available at http://www.epa.gov [Accessed on 10 November 2013].

Giese, A.C. and E. Christensen (1954) Effects of Ozone on Organisms. Physiol. Zool. Vol 27, pp. 101 Cited in Environment Protection Agency (EPA) (1999) EPA Guideline Manual Alternative Disinfectants and Oxidants. [Online] Available at http://www.epa.gov [Accessed on 10 November 2013].

Goldstein, B.D. and E.M. McDonagh (1975) Effect of Ozone on Cell Membrane Protein Flourescence I. in vitro Studies Utilizing the Red Cell Membrane. Environ. Res. Vol 9, pp. 179-186 Cited in Environment Protection Agency (EPA) (1999) EPA Guideline Manual Alternative Disinfectants and Oxidants. [Online] Available at http://www.epa.gov [Accessed on 10 November 2013].

Sato, K. and Saito, T. (2013) A Newly Developed Wastewater Treatment by using Solidification Reaction of Milk Fats and Proteins through Ozonation. [Online] Available at http://www.aidic.it [Accessed on 09 November 2013].

Scott, D.B.M. and Lesher, E.C. (1963) Effect of Ozone on Survival and Permeability of Escherichia Coli. J Bacteriol, 85, pp. 567-576 Cited in Environment Protection Agency (EPA) (1999) EPA Guideline Manual Alternative Disinfectants and Oxidants. [Online] Available at http://www.epa.gov [Accessed on 10 November 2013].

Sproul, O. J. et al. (1982) The Mechanisms of Ozone Inactivation of Waterborne Viruses. Water Sci. Technol., 14, pp.303-314 Cited in Environment Protection Agency (EPA) (1999) EPA Guideline Manual Alternative Disinfectants and Oxidants. [Online] Available at http://www.epa.gov [Accessed on 10 November 2013].

Xylem (2012) Ozone Waste Water Treatment: Oxidizing Micropullutants in Water Circulation [Online]. Available at http://www.xylemwatersolutions.com [Accessed on 7 November 2013].

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