Ca–Fe oxide granules as potential phosphate barrier material for critical source areas: a laboratory study of P retention and release

Authors

  • Risto Uusitalo MTT Agrifood Research Finland
  • Petri Ekholm Finnish Environment Institute
  • Jouni Lehtoranta Finnish Environment Institute
  • Aleksandar Klimeski MTT Agrifood Research Finland
  • Olli Konstari Sachtleben Pigments Oy
  • Riku Lehtonen Sachtleben Pigments Oy
  • Eila Turtola MTT Agrifood Research Finland

Keywords:

Fe oxides, phosphorus, eutrophication, best technologies, permeable reactive barriers

Abstract

Phosphate barriers may mitigate dissolved P losses from critical source areas. We studied P retention of industrially produced Ca–Fe oxide as potential P barrier material. In batch tests with 1 mg l1 P solution, P retention was 85% efficient in 5 min. In a flow-through system, the granule phosphate-retention capacity was 6–7 mg g1, being largely unaffected by pre-leaching. Phosphate release from P-saturated granules was pH-dependant and suggested P association with Fe oxides, and as Ca-phosphate precipitates. In a sequential extraction of P-saturated granules, about 25% of retained P was released, whereas a separate anaerobic incubation resulted in negligible release of P. Immersion of unleached, P-saturated granules for 16 days in a low-P–concentration lake resulted in more than 80% Ca loss, but no loss of metals, and about 25% loss of P accumulated earlier in granules. These granules are promising for P retention and merit a field-scale study.

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Articles

Published

2012-09-28

How to Cite

Uusitalo, R., Ekholm, P., Lehtoranta, J., Klimeski, A., Konstari, O., Lehtonen, R., & Turtola, E. (2012). Ca–Fe oxide granules as potential phosphate barrier material for critical source areas: a laboratory study of P retention and release. Agricultural and Food Science, 21(3), 224–236. https://doi.org/10.23986/afsci.6513
Received 2012-06-18
Accepted 2012-07-02
Published 2012-09-28