Environmental Impacts of Nutrient Removal Processes: Case Study
Publication: Journal of Environmental Engineering
Volume 123, Issue 1
Abstract
The influence of primary clarification of sewage on nitrogen and phosphorus removal in a modified University of Cape Town (UCT) type wastewater-treatment plant (WWTP) has been studied on a full scale. Before or after the introduction of raw sewage, the sludge was characterized on (denitrifying) phosphorus-removing activities by batch tests. For both situations, mass and energy balances in the WWTP were made in order to evaluate the effect of presettling on the environmental impact of the treatment process. Extra chemical oxygen demand (COD) input due to the introduction of raw sewage improved the overall nitrogen removal, whereas P-removal remained good. However, the improvement of nitrogen removal resulted mainly from increased assimilation into extra sludge production, not from increased denitrification. In fact, results of the batch tests indicated that the denitrification activity after the introduction of raw sewage was almost similar to the sludge with presettled sewage. The introduction of raw sewage resulted in an increase of energy consumption, mainly due to lower methane production in the digester. This research shows that evaluating treatment processes solely on effluent quality can easily lead to overall adverse effects for the environment. The full environmental impact should also be considered for treatment processes.
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References
1.
Appeldoorn, K. J. (1993). “Ecological aspects of the biological phosphate removal from waste waters,” PhD thesis, Agric. Univ. of Wageningen, CIP-Gegevens Koninklijke Bibliotheek, The Hague, The Netherlands.
2.
Bortone, G., Malaspina, F., Stante, L., and Tilche, A.(1994). “Biological nitrogen and phosphorus removal in an anaerobic/anoxic sequencing batch reactor with separated biofilm nitrification.”Water Sci. and Technol., 30(6), 303–313.
3.
Comeau, Y., Hall, K. J., and Oldham, W. K.(1990). “Indirect polyphosphate quantification in activated sludge.”Water Pollution Res. J. Canada, 25(2), 161–174.
4.
Janssen, L. P. B. M. (1991). Transport phenomena data companion. Delftse Uitgeversmaatschaooij, Delft, The Netherlands.
5.
Jenkins, D., and Tandoi, V.(1991). “The applied microbiology of enhanced biological phosphate removal∼accomplishments and needs.”Water Res., 25(12), 1471–1478.
6.
Kerrn-Jespersen, J. P., and Henze M. (1993). “Biological phosphorus uptake under anoxic and aerobic conditions.”Water Res., 27(4), 617– 624.
7.
Koot, A. C. J. (1980). Behandeling van afvalwater. Uitgeverij Waltman, Delft, The Netherlands (in Dutch).
8.
Kuba, T., Smolders, G. J. F., van Loosdrecht, M. C. M., and Heijnen, J. J. (1993). “Biological phosphorus removal from wastewater by anaerobic-anoxic sequencing batch reactor.”Water Sci. and Technol., 27(5– 6), 241–252.
9.
Kuba, T., Wachtmeister, A., van Loosdrecht, M. C. M., and Heijnen, J. J.(1994). “Effect of nitrate on phosphorus release in biological phosphorus removal systems.”Water Sci. and Technol., 30(6), 263–269.
10.
Kuba, T., van Loosdrecht, M. C. M., and Heijnen, J. J. (1996a). “Effect of cyclic oxygen exposure on the activity of denitrifying phosphorus removing bacteria.”Proc., 18th IAWQ Biennial Conf., IAWQ, Singapore, Vol. 1, 25–33.
11.
Kuba, T., van Loosdrecht, M. C. M., and Heijnen, J. J.(1996b). “Phosphorus and nitrogen removal with minimal COD requirement by integration of denitrifying dephosphatation and nitrification in a two-sludge system.”Water Res., 30, 1702–1710.
12.
Standard methods for the examination of water and wastewater, 16th Ed. (1985). Am. Public Health Assoc. (APHA), Washington, D.C.
13.
Tchobanoglous, G. (1982). Wastewater engineering: treatment, disposal, reuse. McGraw-Hill Book Co., Inc., New York, N.Y.
14.
Vlekke, G. J. F. M., Comeau, Y., and Oldham, W. K.(1988). “Biological phosphate removal from wastewater with oxygen or nitrate in sequencing batch reactors.”Envir. Technol. Letters, 9(8), 791–796.
15.
Wanner, J., Cech, J. S., and Kos, M. (1992). “New process design for biological nutrient removal.”Water Sci. and Technol., 25(4–5), 445–448.
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Copyright © 1997 American Society of Civil Engineers.
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Published online: Jan 1, 1997
Published in print: Jan 1997
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