title: Reducing phosphorus loading of surface water using iron-coated sand.
abstract: 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.
authors.forename: Jan E
authors.initials: JE
authors.lastname: Groenenberg
authors.forename: Wim J
authors.initials: WJ
authors.lastname: Chardon
authors.forename: Gerwin F
authors.initials: GF
authors.lastname: Koopmans
mesh_terms: D005290:Ferric Compounds; D007501:Iron; D010758:Phosphorus / Q000378:metabolism; D012987:Soil; D014867:Water; D014874:Water Pollutants, Chemical
chemical_list: D005290:Ferric Compounds; D012987:Soil; D014874:Water Pollutants, Chemical; D014867:Water; D010758:Phosphorus; D007501:Iron