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This article in JEQ

  1. Vol. 31 No. 4, p. 1362-1369
    Received: Sept 4, 2001

    * Corresponding author(s): hae1@psu.edu
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Influence of Water Treatment Residuals on Phosphorus Solubility and Leaching

  1. H.A. Elliott *a,
  2. G.A. O'Connorb,
  3. P. Lub and
  4. S. Brintonb
  1. a Agric. and Biol. Eng. Dep., Pennsylvania State Univ., University Park, PA 16802
    b Soil and Water Sci. Dep., Univ. of Florida, Gainesville, FL 32611


Laboratory and greenhouse studies compared the ability of water treatment residuals (WTRs) to alter P solubility and leaching in Immokalee sandy soil (sandy, siliceous, hyperthermic Arenic Alaquod) amended with biosolids and triple superphosphate (TSP). Aluminum sulfate (Al-WTR) and ferric sulfate (Fe-WTR) coagulation residuals, a lime softening residual (Ca-WTR) produced during hardness removal, and pure hematite were examined. In equilibration studies, the ability to reduce soluble P followed the order: Al-WTR > Ca-WTR ≈ Fe-WTR >> hematite. Differences in the P-fixing capacity of the sesquioxide-dominated materials (Al-WTR, Fe-WTR, hematite) were attributed to their varying reactive Fe- and Al-hydrous oxide contents as measured by oxalate extraction. Leachate P was monitored from greenhouse columns where bahiagrass (Paspalum notatum Flugge) was grown on Immokalee soil amended with biosolids or TSP at an equivalent rate of 224 kg P ha−1 and WTRs at 2.5% (56 Mg ha−1). In the absence of WTRs, 21% of TSP and 11% of Largo cake biosolids total phosphorus (PT) leached over 4 mo. With co-applied WTRs, losses from TSP columns were reduced to 3.5% (Fe-WTR), 2.5% (Ca-WTR), and <1% (Al-WTR) of applied P. For the Largo biosolids treatments all WTRs retarded downward P flux such that leachate P was not statistically different than for control (soil only) columns. The phosphorus saturation index (PSI = [Pox]/[Alox + Feox], where Pox, Alox, and Feox are oxalate-extractable P, Al, and Fe, respectively) based on a simple oxalate extraction of the WTR and biosolids is potentially useful for determining WTR application rates for controlled reduction of P in drainage when biosolids are applied to low P-sorbing soils.

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Copyright © 2002. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyPublished in J. Environ. Qual.31:1362–1369.