Sustained phosphorus removal by calcareous materials in long-term (two years) column experiment

Solvei Mundbjerg Jensen*, Helmer Søhoel, Frances Helen Blaikie, Carlos Alberto Arias, Hans Brix

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

10 Downloads (Pure)


(1) Phosphorus (P) removal has proven difficult in decentralized wastewater treatment systems, and external filters installed with a highly P sorbent material have been proposed to improve the P removal. In particular, calcium (Ca) rich materials have shown promising results. (2) Eight materials (five calcareous materials, one quartz sand, and two Sol–Gel coated calcareous materials) were tested in columns fed with P-spiked tap water for two years. The experiment was operated under four periods with increased P concentration from 3.3 to 21.5 mg P L −1, and with increased surface loading rate from 18 to 227 mm d −1 . After termination, the element content was measured in four column height fractions. (3) Initially, all columns removed P effectively and the calcareous materials (CAT, CAT A, and CAT C) maintained an effective removal until termination, while increases in effluent P concentration were detected already after 7 weeks for SAN and after 80–90 weeks for OPO, PHO, CAL, and HYG. The highest P content for materials were measured for the bottom fraction closest to the inlet distribution. For most materials, we observed a good agreement between the maximum sorption capacity (Q max ) and the P content in the bottom fraction; however, a discrepancy was observed for CAL, CAT A, and CAT C. (4) In conclusion, the calcareous materials provided a consistent P removal for all 24 months. Additionally, the Sol–Gel coating had a minimal effect on the P removal capacity contrary to previous findings in batch experiments for the coated materials.

Original languageEnglish
Article number682
Number of pages14
Publication statusPublished - Mar 2022


  • Constructed wetlands
  • Filter
  • Langmuir
  • Material
  • Media
  • Phosphorus
  • Sol–Gel coating
  • Sorption
  • Total P binding capacity
  • Treatment wetlands
  • media
  • total P binding capacity
  • sorption
  • Sol-Gel coating
  • filter
  • treatment wetlands
  • material
  • constructed wetlands
  • phosphorus

Cite this