Evaluation of iron ochre from mine drainage treatment for removal of phosphorus from wastewater

K. E. Dobbie, Katherine Heal, J. Aumonier, K.A. Smith, A. Johnston, P. L. Younger

Research output: Contribution to journalArticlepeer-review

Abstract

Treatment of polluting discharges from abandoned coal mines in the UK currently produces ca 30,000 t y−1 of hydrous iron oxides (“ochre”), for which there is no major end-use, but which has previously been shown to have potential for removing P from wastewater and agricultural runoff. The efficiency of ochre for P removal from wastewater was investigated in experiments at two sites in the UK: Leitholm in Scotland and Windlestone in England. The three-year experiment at Leitholm involved diverting secondary-treated wastewater effluent through a trough which contained granular and pelletized ochre at different times. In the nine-month experiment at Windlestone, beds of ochre pellets in horizontal and vertical flow configurations were tested. The ochre treatment systems at Leitholm reduced influent concentrations of total P (TP) and TP mass by ca 80% and 50%, respectively, during optimal flow conditions, and achieved a removal rate of up to 65 ± 48 mg TP kg−1 ochre d−1. There was no detectable release of potentially toxic metals from the ochre during the experiments. P removal rates by concentration were inversely related to flow and declined during the different phases of the experiments, probably due to clogging. At Windlestone, higher removal rates up to 195 mg TP kg−1 ochre d−1 were achieved for short periods of time following cleaning of the experimental system. Ochre has considerable potential to remove P from wastewater in a multi-stage treatment system and has a lifetime estimated to be 10 times longer than other substrates tested for P removal.
Original languageEnglish
Pages (from-to)795-800
Number of pages6
JournalChemosphere
Volume75
Issue number6
Early online date4 Feb 2009
DOIs
Publication statusPublished - 1 May 2009

Keywords

  • Field experiment
  • Mass removal
  • Operational lifetime
  • Potentially toxic metals
  • Waste recycling
  • Wastewater treatment

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