Hand-pump subsurface arsenic removal: The effect of groundwater conditions and intermittent operation

S. C.Borges Freitas*, D. Van Halem, M. M. Rahman, J. Q.J.C. Verberk, A. B.M. Badruzzaman, W. G.J. Van Der Meer

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)

Abstract

Hand-pump subsurface arsenic removal (SAR) has been investigated in rural Bangladesh with different groundwater conditions and intermittent operation modes. Multiple injection-abstraction cycles were performed after injection of 1 m3 of aerated water. From these experiments it can be concluded that hand-pump SAR, in the traditional injection-abstraction design, does not provide drinking water below the WHO arsenic guideline of 10 μg/L. Results show that arsenic removal was not enhanced by: (i) injection of O2-rich water, (ii) higher Fe:As ratios in the groundwater, or by (iii) multiple injection-abstraction cycles, i.e. at location 1, the breakthrough occurred at abstractioninjection ratios of Va/Vi=2, for cycle 23. It is proposed that dissolved organic carbon (DOC), bicarbonate and phosphate have a significant effect on the arsenic adsorption process. However, iron removal was very efficient and abstraction-injection ratios increased within successive cycles, with Va/Vi>8 for cycle 23. Furthermore, intermittent operation reduced arsenic concentrations after stop and restart, suggesting insufficient contact time between soluble arsenic and oxidized iron surfaces around the tube well.

Original languageEnglish
Pages (from-to)119-126
Number of pages8
JournalWater Science and Technology: Water Supply
Volume14
Issue number1
DOIs
Publication statusPublished - 2014
Externally publishedYes

Keywords

  • Bangladesh
  • Groundwater conditions
  • Hand-pump
  • Intermittent operation
  • Iron
  • Subsurface arsenic removal

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