Control of pH during water denitrification in an upflow bio-electrochemical reactor (UBER) using a pumparound system

Ghafari, S. and Aroua, M.K. and Hasan, M. (2010) Control of pH during water denitrification in an upflow bio-electrochemical reactor (UBER) using a pumparound system. Separation and Purification Technology, 72 (3). pp. 401-405. ISSN 1383-5866

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Abstract

In this study a new reactor design is proposed to control the pH during the bio-electrochemical denitrification process. A previously developed UBER was modified by including a pumparound system. With the pumparound system a portion of the treated water is continuously withdrawn from the UBER into a CO 2 sparging bottle to decrease its pH to about 6.1 ± 0.1, before being returned to the cathode zone where denitrification process takes place. Continuous denitrification was studied with a HRT of 24 h applying an electric current in the range of 15-25 mA. The effects of circulation flow rate (F c) on the pH and on the concentrations of nitrate and nitrite ions in the effluent were investigated. The pumparound system succeeded to stabilize the cathode pH around 7-8 through alteration of circulation flow rate (F c). Complete denitrification with no trace of nitrite was therefore achieved at circulation flow rate of 0.7 mL/min and electric current 25 mA. A further investigation in absence of bicarbonate sodium resulted in a satisfactory nitrate treatment showing that the carbon dioxide gas dissolved in the CO 2 sparging bottle supplied enough carbon for the autohydrogenotrophic microorganisms.

Item Type: Article
Additional Information: Cited By (since 1996):4 Export Date: 21 April 2013 Source: Scopus CODEN: SPUTF :doi 10.1016/j.seppur.2010.03.014 Language of Original Document: English Correspondence Address: Ghafari, S.; Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia; email: shahin@um.edu.my References: Canter, L.W., (1997) Nitrates in Groundwater, , CRC Press; Shrimali, M., Singh, K.P., (2001) Environ. Pollut., 112, pp. 351-359; Guo, Z., Zheng, Z., Gu, C., Zheng, Y., (2008) Radiat. Phys. Chem., 77, pp. 702-707; Moreno-Castilla, C., Bautista-Toledo, I., Ferro-García, M.A., Rivera-Utrilla, J., (2003) Carbon, 41, pp. 1743-1749; Glass, C., Silverstein, J., (1999) Water Res., 33, pp. 223-229; Cast, K.L., Flora, J.R.V., (1998) Water Res., 32, pp. 63-70; Ghafari, S., Hasan, M., Aroua, M.K., (2008) Bioresour. Technol., 99, pp. 3965-3974; Biswas, S., Bose, P., (2005) J. Environ. Eng., 131, pp. 1212-1220; Feleke, Z., Sakakibara, Y., (2002) Water Res., 36, pp. 3092-3102; Killingstad, M.W., Widdowson, M.A., Smith, R.L., (2002) J. Environ. Eng., 128, pp. 491-504; Ghafari, S., Hasan, M., Aroua, M.K., (2009) J. Hazard. Mater., 162, pp. 1507-1513; Ghafari, S., Hasan, M., Aroua, M.K., (2009) J. Biosci. Bioeng., 107, pp. 275-280; Ghafari, S., Hasan, M., Aroua, M.K., (2009) Electrochim. Acta, 54, pp. 4164-4171; Sakakibara, Y.M., Nakayama, T., (2001) Water Res., 35, pp. 768-778; Prosnansky, M., Sakakibara, Y., Kuroda, M., (2002) Water Res., 36, pp. 4801-4810; Zhou, M., Fu, W., Gu, H., Lei, L., (2007) Electrochim. Acta, 52, pp. 6052-6059; Ghafari, S., Hasan, M., Aroua, M.K., (2010) Bioresour. Technol., pp. 2236-2242
Uncontrolled Keywords: Autohydrogenotrophic denitrification; Nitrite; pH; UBER; Circulation flow rate; Denitrification process; Electrochemical denitrification; Electrochemical reactor; Nitrite ion; Reactor designs; Carbon dioxide; Dissolution; Effluents; Electric current measurement; Electric power supplies to apparatus; Electric reactors; Structural design; Water treatment; Denitrification.
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TP Chemical technology
Divisions: Faculty of Engineering
Depositing User: Mr Jenal S
Date Deposited: 16 Jul 2013 05:08
Last Modified: 11 Dec 2013 03:15
URI: http://eprints.um.edu.my/id/eprint/7429

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