Skip to main content


Buy Article:

$17.50 plus tax (Refund Policy)

Or sign up for a free trial

Significant (60–80%) phosphorus (P) release has been reported during anaerobic digestion of BNR sludge. The objectives of this study are to examine the P release in aerobic sludge digestion and to better understand its governing mechanisms. In this study, P release was examined using the secondary sludge from both conventional and BNR processes. The experiments were carried out at room temperature (22 ± 2 °C), with or without automatic control of pH (4.5–7.8), and under three aeration schemes: fully aerobic (DO at 3–4 mg/L), low-DO (0.2–0.8 mg/L), and cyclic (with alternate on/off-aeration). The released P concentrations were 20–80 mg/L for the conventional sludge and 60–130 mg/L for the bio-P sludge. Higher P release also occurred at low pH (< 6.0). As for the effect of DO, fully aerobic digestion caused higher P release than the low-DO and cyclic operations. For better understanding, the solid-P in sludge was conceptually categorized into three forms: the inorganic P precipitates, the organic cellular P, and the poly-P in polyphosphate-accumulating organisms (PAOs). Dissolution of inorganic P precipitates is controlled by physical/chemical conditions, pH being the most important in this study. Lowering pH to 4 – 6 clearly promoted the release of inorganic P. Poly-P hydrolysis, on the other hand, was found regulated biologically (sensitive to occurrence of anaerobic conditions) and was insignificant in the glutaraldehyde-fixed sludge. P release from organic-P should correlate with the VS digestion, which lyses the cells and frees the P covalently bonded with the organic matters. The amounts of P released per unit VS digested, ΔP/ ΔVS, were therefore calculated for experiments with long periods of constant pH (to minimize interferences from dissolution/precipitation of inorganic-P). The results suggested that some poly-P was hydrolyzed and released accompanying the aerobic VS digestion, but at rates far lower than those under anaerobic conditions.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Data/Media
No Metrics

Document Type: Research Article

Publication date: 2002-01-01

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.

    A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Learn about the many other WEF member benefits and join today
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect 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