Sewage Sludge Application Effects on Runoff Water Quality in a Semiarid Grassland
- R. L. Harris-Pierce,
- E. F. Redente and
- K. A. Barbarick *
One of the concerns of land application of sewage sludge (also referred to as biosolids) to rangeland is its effect on the amount and quality of runoff water. In this study, we applied three treatments consisting of 0, 22, and 41 Mg ha−1 of municipal sewage sludge to Larim gravelly sandy loam (Ustollic Arginstoll) and Altvan sandy loam (Aridic Argiustoll) soils in paired plots on two slope gradients (8 and 15%). We used a one-time application of simulated rainfall for 30 rain at a rate of 100 mm h−1 and collected and analyzed the runoff. We found greater sediment loads in the runoff on 8% slopes due to the larger amount of line soil particles (<2-mm diam.) in the soil compared with 15% slopes. As sludge rate increased from 0 to 41 Mg ha−1, decreasing concentrations (P < 0.05) of Al (0.55–0.26 mg L−1) and Fe (0.29–0.15 mg L−1) in unfiltered samples of runoff water resulted. Increasing sludge rate from 0 to 41 Mg ha−1 increased (P ≤ 0.05) sediment (0.5–1.0 g L−1), organic N (0.5–25 mg L−1), NH4-N (0.5–76 mg L−1), and total Na (6.6–10.4 mg L−1), K (4.8–24.8 mg L−1), B (0.016–0.70 mg L−1), P (0.4–15.8 mg L−1), Cu (0.007–0.62 mg L−1), Ni (0.006–0.50 mg L−1), and Mo (0.005–0.52 mg L−1). Concentrations of all measured constituents in the runoff water were less than USEPA standards for drinking water and recommended levels for livestock water.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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