عنوان مقاله [English]
Natural organic matter (NOM) forms the group of principal precursors to organic disinfection by-products (DBPS), which have been recognized to be human carcinogens. In fact, a high TOC concentration, used as an indicator of NOM, indicates a high potential for DBP formation. The aim of the present work was to investigate the effects of nanofiltration with and without preozonation on TOC removal. Nanofiltration alone at operating pressures of 4 and 8 bars could reduce TOC levels to slightly less than 2 mgL-1, which recorded a profile of success for all the experiments. This is while preozonation at a concentration of 2 mgL-1 recorded an effluent TOC level of 3.3 mgL-1, which is not an acceptable record. Preozonation at a concentration of 4 mgL-1 increased effluent TOC to 4.2 mgL-1, which indicates that preozonation could convert NOM from higher- to lower-MW fractions, thus increasing effluent TOC. It was also shown that preozonation-nanofiltration increased effluent TOC, as compared to nanofiltration alone.
1- Tchobanoglous, G., and Burton, F. (2003). Wastewater engineering: treatment and reuse, 4th Ed., McGraw-Hill, Metcalf and Eddy Inc.,New York.
2- Edwards, M., and Benjamin, M. M. (1992). “Effect of Pre-ozonation on coagulant-NOM-interactions.” J. AWWA, 84 (8), 63-72.
3- Manttari, M., and Nystrom, M. (2006). “Negative retention of organic compound in nanofiltration.” Desalination, 199(1-3), 41-42.
4- Torabian, A., Ghadimkhani, A. A., Rashidi Mehrabadi, A., Shokouhi, M., and Heidarzadeh, R. (2007). “Effect of pre-ozonation on total organic carbon removal in surface water treatment in Iran.” WIT, Water Resource Management,Bologna,Italy.
5- ترابیان، ع.، شکوهی هرندی، م.، نبی بیدهندی، غ.ر.، قدیمخانی، ع. ا.، و صفاییفر، م. (1386). ” بررسی کارایی یک غشای نانوفیلتراسیون در حذف نیترات از آب آشامیدنی در شرایط عملی مختلف. “م. آب و فاضلاب، 61، 15-24.
6- Frimmel, F. H., and Christman, R. F. (1988). Humic substances and their role in the environment, 1st Ed., John Wiley and Sons,New York.
7- Chen, K. C. (2003). “Ozonation, ultrafiltration and biofiltration for the control of NOM and DBP in drinking water.” J. AWWA., 82, 78-88.
8- Chen, K.C., and Masten, S.J. (2005). “Effect of combined ozonation-ultra filtration on membrane fouling and water quality.” J. of the Chinese Institute of Environmental Engineering, 15(4), 263-268.
9- Yavich, A. A. (1998). “The use of ozonation and biological fluidized bed treatment for the control of NOM in drinking water.” AWWA, 81, 45-52.
10- Karnik, B. S., Pavies, S. H., Baumann, M. J., and Masten, S. J. (2005). “The effect of combined ozonation and filtration on disinfection by-product formation.” Water Research, 39(13), 2839-2850.