$17.50 plus tax (Refund Policy)

Buy Article:


This study investigated stoichiometric relationships between metal cations (Ca2+, Mg 2+, K+, Na+, Al3+ and Fe (II and III)) and P uptake and release in full-scale EBPR activated sludge treatment plants with a range of configurations and influent wastewater characteristics.

The plants had specific P uptake and release rates ranging from 1.4 to 24 mg P/g VSS-h and ratio of anaerobic volatile fatty acids (VFA) uptake to P release ranging from 0.2 to 0.5 (gP/gHAc), indicating a significant difference in populations of the poly-phosphateaccumulating organisms (PAO) in the mixed liquors tested.

The K+/P and Mg2+/P mole ratios observed during the P release and uptake tests varied from plant to plant and ranged from 0.15 to 0.48 for K+/P and from 0.27 to 0.48 for Mg2+/P. We found that cation/P mole ratios measured during anaerobic P release can differ significantly from those measured during aerobic P uptake. In general the cation/Prelease ratio was lower than the cation/Puptake ratio for Ca and Mg. While no consistent difference between K+ and Prelease and K+/Puptake ratios was observed. Three out of the six plants clearly showed the association of Ca with phosphate uptake and release. The Ca2+/Prelease ratio ranged from 0.07 to 0.28. The other three did not show a direct correlation of soluble Ca2+ and phosphate uptake and release based on the soluble Ca2+ and P measured. However, further evaluation of Ca2+ and PO4 3− concentrations and pH indicated chemical precipitation could occur under the study conditions. The correlation of Ca2+ to P uptake and release clearly shown in this study demonstrated that Ca2+ actually plays just as important a role as Mg2+ in the biological P-removal process. The Ca2+ availability in the influent should thus be evaluated together with Mg2+ when investigating whether poor performance of an EBPR process may be related to possible metal limiting conditions.

Document Type: Research Article

DOI: http://dx.doi.org/10.2175/193864704784131608

Publication date: January 1, 2004

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 These proceedings are not peer reviewed.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