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Managing Biosolids Runoff Phosphorus Using Buffer Strips Enhanced with Drinking Water Treatment Residuals
Author(s) -
Wagner D. J.,
Elliott H. A.,
Brandt R. C.,
Jaiswal D.
Publication year - 2008
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2007.0338
Subject(s) - biosolids , buffer strip , surface runoff , phosphorus , environmental science , water quality , environmental engineering , environmental chemistry , chemistry , ecology , organic chemistry , biology
Abstract Vegetated buffers strips typically have limited ability to reduce delivery of dissolved phosphorus (DP) from agricultural fields to surface waters. A field study was conducted to evaluate the ability of buffer strips enhanced with drinking water treatment residuals (WTRs) to control runoff P losses from surface‐applied biosolids characterized by high water‐extractable P (4 g kg − 1 ). Simulated rainfall (62.4 mm h −1 ) was applied to grassed plots (3 m × 10.7 m including a 2.67 m downslope buffer) surface‐amended with biosolids at 102 kg P ha −1 until 30 min of runoff was collected. With buffer strips top‐dressed with WTR (20 Mg ha −1 ), runoff total P (TP = 2.5 mg L −1 ) and total DP (TDP = 1.9 mg L −1 ) were not statistically lower (α = 0.05) compared to plots with unamended grass buffers (TP = 2.7 mg L −1 ; TDP = 2.6 mg L −1 ). Although the applied WTR had excess capacity (Langmuir P maxima of 25 g P kg −1 ) to sorb all runoff P, kinetic experiments suggest that sheet flow travel time across the buffers (∼30 s) was insufficient for significant P reduction. Effective interception of dissolved P in runoff water by WTR‐enhanced buffer strips requires rapid P sorption kinetics and hydrologic flow behavior ensuring sufficient runoff residence time and WTR contact in the buffer. Substantial phosphate‐adsorbent contact opportunity may be more easily achieved by incorporating WTRs into P‐enriched soils or blending WTRs with applied P sources.