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Review

Kanchan Arsenic Filters for Household Water Treatment: Unsuitable or Unsustainable?

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School of Earth Science and Engineering, Hohai University, Fo Cheng Xi Road 8, Nanjing 211100, China
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Faculty of Science, Department of Chemistry, University of Maroua, Maroua P.O. Box 46, Cameroon
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Biosystems and Environmental Engineering Research Group, Department of Agricultural and Biosystems Engineering, University of Zimbabwe, Mount Pleasant, Harare P.O. Box MP167, Zimbabwe
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Centre for Modern Indian Studies (CeMIS), Universität Göttingen, Waldweg 26, D-37073 Göttingen, Germany
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Department of Applied Geology, University of Göttingen, Goldschmidtstraße 3, D-37077 Göttingen, Germany
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Department of Water and Environmental Science and Engineering, Nelson Mandela African Institution of Science and Technology, Arusha P.O. Box 447, Tanzania
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Faculty of Science and Technology, Campus of Banekane, Université des Montagnes, Bangangté P.O. Box 208, Cameroon
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Authors to whom correspondence should be addressed.
Academic Editor: Christos S. Akratos
Water 2022, 14(15), 2318; https://doi.org/10.3390/w14152318
Received: 23 May 2022 / Revised: 21 July 2022 / Accepted: 23 July 2022 / Published: 26 July 2022
(This article belongs to the Special Issue Sustainable Remediation Using Metallic Iron: Quo Vadis?)
This article critically evaluates the conventional Kanchan Arsenic Filter (KAF) in order to determine the main reasons for its reported poor performance. The KAF was introduced in 2004 in Nepal and makes use of non-galvanized nails as a Fe0 source for As removal. As early as 2009, the KAF was demonstrated to be ineffective for As removal in many cases. This was unambiguously attributed to the Fe0 layer which is placed on top of a sand filter instead of being incorporated into a sand matrix. Despite this conceptual mistake, the conventional KAF has been largely distributed in Asia, and recent articles have assessed its sustainability. This study reiterates that the suitability of the technology, rather than its sustainability, should be addressed. Evidence shows that the KAF has the following design limitations: (i) uses iron nails of unknown reactivity, and (ii) operates on the principle of a wet/dry cycle. The latter causes a decrease in the corrosion rate of the used nails, thereby limiting the availability of the iron corrosion products which act as contaminant scavengers. Taken together, these results confirm the unsuitability of the conventional KAF. Besides correcting the design mistakes, more attention should be paid to the intrinsic reactivity of the used iron nails, including using alternative Fe0 materials (e.g., iron filings, steel wool) for filters lasting for just 6 or 18 months. Specific design considerations to be addressed in the future are highlighted. View Full-Text
Keywords: arsenic removal; groundwater pollution; household water filter; public health; zero-valent iron arsenic removal; groundwater pollution; household water filter; public health; zero-valent iron
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MDPI and ACS Style

Ndé-Tchoupé, A.I.; Konadu-Amoah, B.; Gatcha-Bandjun, N.; Hu, R.; Gwenzi, W.; Noubactep, C. Kanchan Arsenic Filters for Household Water Treatment: Unsuitable or Unsustainable? Water 2022, 14, 2318. https://doi.org/10.3390/w14152318

AMA Style

Ndé-Tchoupé AI, Konadu-Amoah B, Gatcha-Bandjun N, Hu R, Gwenzi W, Noubactep C. Kanchan Arsenic Filters for Household Water Treatment: Unsuitable or Unsustainable? Water. 2022; 14(15):2318. https://doi.org/10.3390/w14152318

Chicago/Turabian Style

Ndé-Tchoupé, Arnaud Igor, Bernard Konadu-Amoah, Nadège Gatcha-Bandjun, Rui Hu, Willis Gwenzi, and Chicgoua Noubactep. 2022. "Kanchan Arsenic Filters for Household Water Treatment: Unsuitable or Unsustainable?" Water 14, no. 15: 2318. https://doi.org/10.3390/w14152318

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