Reducing Phosphorus Loading of Surface Water Using Iron‐Coated Sand

• Published in: Journal of environmental quality Vol. 42; no. 1; pp. 250 - 259
• Main Authors: Groenenberg, Jan E., Chardon, Wim J., Koopmans, Gerwin F.
• Format: Journal Article
• Language: English
• Published: United States The American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc 01.01.2013; American Society of Agronomy
• Subjects: agricultural land; Agriculture; drainage; Ferric Compounds; flooded soils; grassland soils; groundwater; Iron; Load; phosphate; Phosphorus - metabolism; reduction; removal; Soil; Soils; Surface water; treatment residuals; waste-water; Water; Water Pollutants, Chemical; Water pollution; Water quality; Netherlands
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2012.0344

Phosphorus losses from agricultural soils is an important source of P in surface waters leading to surface water quality impairment. In addition to reducing P inputs, mitigation measures are needed to reduce P enrichment of surface waters. Because drainage of agricultural land by pipe drainage is an important pathway of P to surface waters, removing P from drainage water has a large potential to reduce P losses. In a field trial, we tested the performance of a pipe drain enveloped with Fe‐coated sand, a side product of the drinking water industry with a high ability to bind P, to remove P from the drainage water. The results of this trial, encompassing more than one hydrological season, are very encouraging because the efficiency of this mitigation measure to remove P amounted to 94%. During the trial, the pipe drains were below the groundwater level for a prolonged time. Nevertheless, no reduction of Fe(III) in the Fe‐coated sand occurred, which was most likely prevented by reduction of Mn oxides present in this material. The enveloped pipe drain was estimated to be able to lower the P concentration in the effluent to the desired water quality criterion for about 14 yr. Manganese oxides are expected to be depleted after 5 to 10 yr. The performance of the enveloped pipe drain, both in terms of its ability to remove P to a sufficiently low level and the stability of the Fe‐coated sand under submerged conditions in the long term, needs prolonged experimental research.