Sains Malaysiana 41(6)(2012): 739 –745

Physicochemical and Microbiological Analysis of Drinking

Water Treated by Using Ozone

(Analisis Fisikokimia dan Mikrobiologi Air Minimum yang dirawat dengan Ozon)

D.P. Subedi & A. Khadgi

Department Of Natural Science, Kathmandu University, Dhulikhel, Nepal

R.B. Tyata

Department Of Physics, Khwopa College, Dekocha, Bhaktapur, Nepal

C.S. Wong*

Plasma Technology Research Centre, Physics Department, University Of Malaya

50603 Kuala Lumpur, Malaysia

Received: 13 July 2011 / Accepted: 5 January 2012

ABSTRACT

This study focused on the application of a Dielectric Barrier Discharge (DBD ) unit to produce highly oxidizing ozone molecules for the treatment of drinking water. The samples of water were collected from three different sources, namely tap, stone spout and tube-well in the Kathmandu valley. Various physical, chemical and micro-biological analyses were carried out to both the ozone treated and untreated samples of water for comparison. Our results indicated that ozone does not alter the physical characteristics, namely pH, conductivity and turbidity of water but it has significant effect on the chemical properties such as nitrate concentration, total hardness, calcium hardness, Fe(II) and Fe(III) concentration. It was observed that ozone efficiently precipitates ferrous ion into ferric ion and is effective in the removal of fecal coliform, a key element for various water related health problems in most of the developing countries. It is shown that the treatment with ozone leads to a significant reduction in the number of fecal coliform in the samples of drinking water from tap, stone spout and tube well with p values 0.00182, 0.026 and 5.8 ×10-15, respectively at 0.05 level of significance.

Keywords: Dielectric barrier discharge; ozone; water treatment

ABSTRAK

Kajian ini berfokus kepada kegunaan molekul ozon yang dihasilkan daripada nyahcas dielektrik berpenghadang (DBD) untuk membersihkan air minimum. Sampel air dari paip air, batu spout dan perigi tuib di Lembah Kathmandu telah dirawati dengan ozon. Pelbagai analisis cirian fizikal, kimia dan mikrobiologi telah dilakukan ke atas sampel air sebelum dan selepas dirawat dengan ozon. Hasil analisis menunjukkan bahawa rawatan ozon tidak mengakibatkan perubahan kepada cirian fizikal seperti nilai pH, kekonduksian dan kekeruhan tetapi membawa kesan terhadap cirian kimia seperti kepekatan nitrat, keliatan keseluruhan, keliatan kalsium, kepekatan Fe(II) dan Fe(III). Ozon didapati sangat berkesan untuk menukarkan ion ferus kepada ferik dan berjaya menghapuskan koliform feses yang merupakan satu masalah penting tentang kebersihan air yang dihadapi oleh kebanyakan negara membangun. Hasil kajian ini menunjukkan bilangan koliform feses dalam air dapat di kurangkan secara berkesan dengan rawatan ozon, ia itu nilai p untuk sampel air minumam dari paip air, batu spout dan perigi tuib adalah 0.00182, 0.026 dan 5.8 ×10-15, masing-masing pada aras tekal bernilai 0.05.

Kata kunci: Nyahcas dielektrik berpenghadan; ozon; perawatan air

REFERENCES

American Public Health Association, American Water. 1995. Works Association and Water Environment Federation 1995, Standard Methods for Examination of Water and Waste water. 19th edition.

Bubnov, A.G., Grinevich, V.I. & Kurykin, N.A. 2004. The Kinetics of Plasma-Induced Degradation of Organic Pollutants in Sewage Water. High Energy Chemistry 38: 41-45.

Chang, M.B. & Wu, S.J. 1997. Experimental study on ozone synthesis via dielectric barrier discharges. Ozone Science Engineering 19: 241-254.

Eliasson, B., Hirth, M. & Kogelschatz, U. 1987. Ozone synthesis from oxygen in dielectric barrier discharges. Journal Phys. D: Applied Phys. 20: 1421-1437.

Gupta, P.K. 2000. Methods of Environmental Analysis: Water, Soil and Air. (1st ed.). Jodhpur, India: Agrobios.

Kuraica, M.M., Obradovic, B.M., Manojlovic, D., Ostojic, D.R. & Puric, J. 2004. Ozonized water generator based on coaxial dielectric-barrier-discharge in air. Vacuum 73: 705-708.

Malik, M.A., Ghaffar, A. & Malik, S.A. 2001. Water purification by electrical processing. Plasma Sources Sci. Technol.10: 82-91.

McNair, D.B. & Lesher E.C., 1963. Effect of ozone on survival and permeability of Escherichia coli. J. Bacteriol.85: 567–576.

Moris, K. 1977. Methods of Air Sampling and Analysis, 2nd Ed. Washington DC: Apha Intersociety Committee.

Patrick, N., Robert, H., Pierre, L. & Maurice, L. 2007. An innovative process for the treatment of high loaded surface waters for small communities. J. Environ. Eng. Sci.6: 139-145.

Rajeswari, K.R., Noorsaadah, A.R. & Wong, C.S. 2001. Effect of temperature on the ozonation of textile waste effluent. Coloration Technology 117: 95-97.

Shrestha, G., Freere, P., Basnet, S.M., Jewel, W.T. & Subedi, D.P. 2007. Development of a Cold Plasma Generator for Atmospheric Pressure Dielectric Barrier Discharge. IEEE, Region 5 Technical Conference.

Subedi, D.P., Tyata, R., Khadgi, A. & Wong, C.S. 2009. Treatment of water by dielectric barrier discharge. Journal of Science and Technology in the Tropics 5: 117-123.

Sunka, P., Babicky, V., Clupek, M., Lukes, P., Simek, M, Schmidt, J. & Cernak, M. 1999. Generation of chemically active species by dielectric barrier discharges in water. Plasma Sources Sci. Technol. 8: 258-265.

*Corresponding author; email:cswong@um.edu.my