African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12487

Full Length Research Paper

Application of solar treatment for the disinfection of geophagic clays from markets and mining sites

Fosso-Kankeu E.*
  • Fosso-Kankeu E.*
  • School of Chemical and Minerals Engineering, Faculty of Engineering, North-West University, P. O. Box 558, Potchefstroom 2531, South Africa.
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Netshitanini T. L.
  • Netshitanini T. L.
  • School of Chemical and Minerals Engineering, Faculty of Engineering, North-West University, P. O. Box 558, Potchefstroom 2531, South Africa.
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Abia A. L. K.
  • Abia A. L. K.
  • Department of Environmental, Water and Earth Science, Tshwane University of Technology, 175 Nelson Mandela Drive, Pretoria 0001, South Africa.
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Ubomba-Jaswa E.
  • Ubomba-Jaswa E.
  • Natural Resources and the Environment, CSIR, P. O. Box 395, Pretoria 0001, South Africa.
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Waanders F. B.
  • Waanders F. B.
  • School of Chemical and Minerals Engineering, Faculty of Engineering, North-West University, P. O. Box 558, Potchefstroom 2531, South Africa.
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  •  Received: 16 September 2015
  •  Accepted: 12 October 2015
  •  Published: 16 December 2015

Abstract

Most of the microorganisms occurring in geophagic clays are undesirable and may to some extent be harmful to geophagists; it is therefore important to develop a cheap and sustainable technique for the treatment of these clays prior to consumption. In this study, a solar treatment simulated in a chamber has been investigated for its potential to inactivate the microorganisms found in the geophagic clays obtained from mining sites and from the markets. The results have shown that irrespective of the sources of the clays, they were contaminated with large amount of potentially harmful microorganisms which could have been sustained by suitable conditions such as relatively high moisture content (average of 3.6%) and the presence of organic carbon (between 1.06 and 1.5%). Treatment with simulated solar irradiation has resulted in most instances to the reduction of the number (up to 100% inactivation) of microorganisms although in few cases the same conditions have stimulated the growth of some dormant microorganisms including Bacillus subtilis, Paenibacillus, Bacillus cereus, Bacillus thuringiensis, Bacillus humi and Arthrobacterarilaitensis. This study shows that the solar treatment has the potential to significantly reduce the amount of microorganisms occurring in the geophagic clays, but require further investigation for improvement of the technique.
 
Key words: Geophagic clays, solar treatment, microorganisms, moisture content, organic carbon, mining sites, markets.