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This article in JEQ

  1. Vol. 29 No. 6, p. 1896-1904
    Received: Sept 30, 1999

    * Corresponding author(s): tmorris@canr.cag.uconn.edu
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Phosphorus Availability in Soils Amended with Dewatered Water Treatment Residual and Metal Concentrations with Time in Residual

  1. J. E. Hyde and
  2. T. F. Morris *
  1. Department of Plant Science, Univ. of Connecticut, 1376 Storrs Road, Storrs, CT 06269.



The objective of this laboratory study was to measure the effect of dewatered water treatment residual (WTR) on extractable P and Al in soils with above-optimum P concentrations. A secondary objective was to document the variability of the metal content of WTR during 1 yr. Two soils, a Paxton fine sandy loam (coarse-loamy, mixed, active, mesic Oxyaquic Dystrudept) and an Enfield silt loam (coarse-silty over sandy or sandy-skeletal, mixed, active, mesic Typic Dystrudept) with above-optimum Mehlich 3 P concentrations (833 mg kg−1 and 630 mg kg−1, respectively) were amended with four dewatered WTRs. The WTRs were dewatered using three treatments: (i) WTR dewatered at 40°C in a forced-air oven (DRY), (ii) WTR dewatered by freezing at −4°C and then dried at 40°C in a forced-air oven (FROZEN), and (iii) WTR dewatered to 4.5% solids at 40°C in a forced-air oven (RAW). The WTRs were added to the soils at rates of 20 or 60 g kg−1 and incubated for 21 d. The WTRs in the RAW treatment significantly reduced Mehlich 3 P concentrations compared with the DRY and FROZEN treatments. The RAW treatment reduced soil P concentrations an average of 64% compared with a reduction of 28% for the DRY treatment and 23% for the FROZEN treatment. The results suggest that the method used to dewater WTR will alter its ability to decrease Mehlich 3 P soil concentrations. The secondary objective involved collection of two of the WTRs every 3 wk for 1 yr and subsequent analysis for metal concentrations. The metal concentrations changed little during the year and only Cu, due to its use as an algicide, was elevated.

Storrs Agric. Exp. Stn. Journal Paper no. 1914.

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