NSU Research Contributions
Title : Hand-pump subsurface arsenic removal: The effect of groundwater conditions and intermittent operation.
Authors : S.C.B., Freitas, D. Van Halem, M.M. Rahman, J.Q.J.C. Verberk, A.B.M. Badruzzaman, W.G.J. Van Der Meer,
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 ?g/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 ΒΌ 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.
| Journal : Water Science and Technology: Water Supply | Volume : 14 | Year : 2014 | Issue : 1 |
| Pages : 119-126 | City : | Edition : | Editors : |
| Publisher : | ISBN : | Book : | Chapter : |
| Proceeding Title : | Institution : | Issuer : | Number : |
