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A three-step test of phosphate sorption efficiency of potential agricultural drainage filter materials

Lyngsie, G. LU ; Borggaard, O. K. and Hansen, H. C B (2014) In Water Research 51. p.256-265
Abstract

Phosphorus (P) eutrophication of lakes and streams, coming from drained farmlands, is a serious problem in areas with intensive agriculture. Installation of P sorbing filters at drain outlets may be a solution. Efficient sorbents to be used for such filters must possess high P bonding affinity to retain ortho-phosphate (Pi) at low concentrations. In addition high P sorption capacity, fast bonding and low desorption is necessary. In this study five potential filter materials (Filtralite-P®, limestone, calcinated diatomaceous earth, shell-sand and iron-oxide based CFH) in four particle size intervals were investigated under field relevant P concentrations (0-161μM) and retentions times of 0-24min. Of the five materials... (More)

Phosphorus (P) eutrophication of lakes and streams, coming from drained farmlands, is a serious problem in areas with intensive agriculture. Installation of P sorbing filters at drain outlets may be a solution. Efficient sorbents to be used for such filters must possess high P bonding affinity to retain ortho-phosphate (Pi) at low concentrations. In addition high P sorption capacity, fast bonding and low desorption is necessary. In this study five potential filter materials (Filtralite-P®, limestone, calcinated diatomaceous earth, shell-sand and iron-oxide based CFH) in four particle size intervals were investigated under field relevant P concentrations (0-161μM) and retentions times of 0-24min. Of the five materials examined, the results from P sorption and desorption studies clearly demonstrate that the iron based CFH is superior as a filter material compared to calcium based materials when tested against criteria for sorption affinity, capacity and stability. The finest CFH and Filtralite-P® fractions (0.05-0.5mm) were best with P retention of ≥90% of Pi from an initial concentration of 161μM corresponding to 14.5mmol/kg sorbed within 24min. They were further capable to retain ≥90% of Pi from an initially 16μM solution within 11/2 min. However, only the finest CFH fraction was also able to retain ≥90% of Pi sorbed from the 16μM solution against 4 times desorption sequences with 6mM KNO3. Among the materials investigated, the finest CFH fraction is therefore the only suitable filter material, when very fast and strong bonding of high Pi concentrations is needed, e.g. in drains under P rich soils during extreme weather conditions.

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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Carbonates, Eutrophication, Farmland drainage, Iron oxides, Water quality
in
Water Research
volume
51
pages
10 pages
publisher
Elsevier
external identifiers
  • scopus:84895074248
ISSN
0043-1354
DOI
10.1016/j.watres.2013.10.061
language
English
LU publication?
no
id
4d7fe350-0464-4af1-8801-676368c5f68d
date added to LUP
2016-10-17 14:08:45
date last changed
2017-08-06 05:12:17
@article{4d7fe350-0464-4af1-8801-676368c5f68d,
  abstract     = {<p>Phosphorus (P) eutrophication of lakes and streams, coming from drained farmlands, is a serious problem in areas with intensive agriculture. Installation of P sorbing filters at drain outlets may be a solution. Efficient sorbents to be used for such filters must possess high P bonding affinity to retain ortho-phosphate (Pi) at low concentrations. In addition high P sorption capacity, fast bonding and low desorption is necessary. In this study five potential filter materials (Filtralite-P<sup>®</sup>, limestone, calcinated diatomaceous earth, shell-sand and iron-oxide based CFH) in four particle size intervals were investigated under field relevant P concentrations (0-161μM) and retentions times of 0-24min. Of the five materials examined, the results from P sorption and desorption studies clearly demonstrate that the iron based CFH is superior as a filter material compared to calcium based materials when tested against criteria for sorption affinity, capacity and stability. The finest CFH and Filtralite-P<sup>®</sup> fractions (0.05-0.5mm) were best with P retention of ≥90% of Pi from an initial concentration of 161μM corresponding to 14.5mmol/kg sorbed within 24min. They were further capable to retain ≥90% of Pi from an initially 16μM solution within 11/2 min. However, only the finest CFH fraction was also able to retain ≥90% of Pi sorbed from the 16μM solution against 4 times desorption sequences with 6mM KNO<sub>3</sub>. Among the materials investigated, the finest CFH fraction is therefore the only suitable filter material, when very fast and strong bonding of high Pi concentrations is needed, e.g. in drains under P rich soils during extreme weather conditions.</p>},
  author       = {Lyngsie, G. and Borggaard, O. K. and Hansen, H. C B},
  issn         = {0043-1354},
  keyword      = {Carbonates,Eutrophication,Farmland drainage,Iron oxides,Water quality},
  language     = {eng},
  month        = {03},
  pages        = {256--265},
  publisher    = {Elsevier},
  series       = {Water Research},
  title        = {A three-step test of phosphate sorption efficiency of potential agricultural drainage filter materials},
  url          = {http://dx.doi.org/10.1016/j.watres.2013.10.061},
  volume       = {51},
  year         = {2014},
}