A Comparative Study of Nitrification Inhibition by Heavy Metals: the Influence of Metal Exposure Time on Biological Effect

$17.50 plus tax (Refund Policy)

Buy Article:


Stringent effluent discharge limits for nitrogen from wastewater treatment facilities require development of assays to accurately and rapidly determine whether a wastewater stream will inhibit nitrification. Using biomass from a well-controlled continuously-operated lab-scale nitrifying bioreactor, the suitability of batch extant respirometric assays to predict nitrification inhibition in a continuous flow reactor was evaluated. The effect of Cu, Zn, Ni and Cd on ammonium and nitrite oxidation was quantified. Metal partitioning coefficients (Kp) were first determined in separate batch experiments at 78.42 2.46, 0.54 0.04, 0.05 0.01 and 0.60 0.01 L/g XCOD for Cu, Zn, Ni and Cd, respectively. A reactor mass-balance model incorporating partitioning adequately fit the dynamics of all metals in the continuous flow reactor during and after a 24-hour shock load. However, short-term batch assays significantly underestimated inhibition in the continuous flow reactor if no corrections were made. The underestimation was, most likely, due to the slow kinetics of Zn, Ni and Cd internalization and the effect of continued metal exposure in the continuous flow reactor. However, the discrepancy in inhibition by Cu was the largest among the four metals tested, presumably due to its unique mode of action. Hence, using results from short-term batch inhibition assays to infer responses in the continuous flow reactors with longer exposure should be done with caution.

Document Type: Research Article

DOI: http://dx.doi.org/10.2175/193864702785073299

Publication date: January 1, 2002

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • ingentaconnect is not responsible for the content or availability of external websites



Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more