Investigation of the Effect of a Flocculent of Bentonite Clay with MgCO3 in Synthetic Acid Mine Drainage (AMD) Treatment

  • Oupa I. Ntwampe(1*)
    University of Johannesburg
  • K. Moothi(2)
    University of Johannesburg
  • (*) Corresponding Author
Keywords: wastewater, coagulants, AMD, mixing, shaking, turbidity


Effect of a flocculent of bentonite clay with MgCO3 in Synthetic AMD was investigated in present study. The AMD samples were collected from the western decant in Krugersdorp, South Africa was modified by adding arsenic, zinc and cobalt. The pH, conductivity, dissolved oxygen (DO), oxygen reduction potential (ORP) and turbidity were measured. Those samples were treated with bentonite clay, MgCO3 and a flocculent of bentonite clay and MgCO3 respectively in a jar test, employing either rapid or slow mixing. Results showed that the conductivity of the samples with increasing bentonite clay while keeping MgCO3 constant decreased with increasing dosage, which was attributed to adsorption of the ions onto the negative sites of the porous bentonite when ionic strength increased. The oxygen content of the DO and ORP was not influenced by the rate of mechanical agitation, i.e. rapid and slow mixing respectively. Destabilization-hydrolysis was not influenced by the pH but the ionic strength of the colloidal AMD suspension, valence and electronegative of the metal ions. Turbidity removal of the synthetic flocculent used occured through physico-chemical phenomenon (SEM micrographs) and charged porous bentonite clay. In conclusion: Bentonite clay controls equilibrium state of the ionic strength of the system through adsorption of excess ions added to the system. Velocity gradient induced by mechanical agitation does not have an influence on the turbidity removal.

Keywords: wastewater, coagulants, AMD, mixing, shaking, turbidity


Download data is not yet available.


Aboulhassan MA, Souabi S, Yaacoubi A, and Bauda M. 2006. Removal of surfactant from industrial wastewaters by coagulation flocculation process. Interface Journal of Environmental Science & Technology 3(4): 327-336. DOI:
Akcil A. and Koldas S. 2006. Acid minedrainage: causes, treatment and case studies. J Clean. Prod. 14: 1139-1145. DOI:
Aubẻ B and Arseneault B. 2003. “In-Pit Mine Drainage Treatment System in a Northern Ulmate” In Proceedings for Sudbbury Mining and Environment Conference” available at
Bratby J. 2006. Coagulants in Coagulation and Flocculation in Water and Wastewater Treatment, second (ed), IWA Publishing, London, p. 50-68.
Dzombak DA and Hudson RJM. 1995. In “Aquatic Chemistry: Interfacial and Interspecies Process” (C.P. Huang, C.R. O’Melia and J.J. Morgan, Eds.), p. 59, Am. Chem. Soc.
Washington DC. USA. DOI:
EEB. 2000. The environmental performance of the mining industry and the action necessary to strengthen European legislation in the wake of the Tisza-Danube pollution, European Environmental Bureau, Document No. 2000/016, p. 32.
Ekosse G-IE, Jumbam ND. 2010. Geophagic clays: their mineralogy, chemistry and possible human health effects. Afri. J Biotechnol. 9: 6755–6767.
Emmanuel IU, Jens CW, Lubahn S and Taubert A. 2013. Hybrid Clay: A New Highly Efficient Adsorbent for Water Treatment, Chem. Eng. 1 (8) : 966-973.
Gitari WM, Kaseke C, and Nkuzani BB. 2011. Passive Remediation of Acid Mine Drainage using Bentonite Clay: A Laboratory Batch Experimental Study. Int. Mine Wat. Asso. 325-330.
Kurniawan TA, Chan WS, Lo WH, and Babel S. 2006. Physicochemical treatment techniques for wastewater laden with heavy metals. J. Chem. Eng. 118: 83-87. DOI:
Mail & Guardian. 2005. A risong acid tide by Mellisa Fourie, 12 April 2005.
Pulles W, Banister S, and van Biljon M. 2005. The development of appropriate procedures towards and after closure of underground gold mines from a water management perspective, Report No. 1215/1/05, Wat. Res. Com. Pretoria, South Africa.
Mansri A, Bendraoua A, Benmoussa A, and Benhabib K. 2015. New Polyacrylamide [PAM] Material Formulations for the Coagulation/Flocculation/Decantation Process, J. Polymer and Environ. 23
(4): 580-587. DOI:
Maree JP. 2004. Treatment of industrial effluent for neutralization and sulphate removal; A thesis submitted for PhD at the North West University, RSA.
Nagajyoti PC, Lee KD, and Sreekanth TVM. 2010. Heavy metals, occurrence and toxicity for plants: a review. Environ. Chem. 8: 199–216. DOI:
Nel M, Waander FB, and Fosso-Kankeu E. 2014. Adsorption potential of bentonite and attapulgite clays applied for the desalination of sea water. Conference Report. Cape Town: 6th International Conference on Green Technology, Renewable Energy & Environmental Engineering NorthWest University.
Ntwampe IO, Jewell LL, and Glasser D. 2013. The effect of mixing on the treatment of paint wastewater with Fe 3+ and Al 3+ salts. J. of Environ. Chem. and Ecotoxicol. 5(1): 7-16.
Ntwampe IO, Waanders FB, Fosso-Kankeu E, and Bunt JR. 2015a. Turbidity removal efficiencies of clay and af-PFCl polymer of magnesium hydroxide in AMD treatment, Int. J Sci. Res. 4: 38-55.
Ntwampe IO, Waanders FB, and Bunt JR. 2015b. Optimization of a polymeric reagent of clay and varying concentrations of FeCl3 with dolomite dosage in AMD treatment, submitted to J. Mine Wat. and Environ. [Unpublished].
Ntwampe IO, Waanders FB, and Bunt JR. 2016. Destabilization dynamics of clay and acid-free polymers of ferric and magnesium salts in AMD without pH adjustment, Wat. Sci. & Technol. 74, 4: 861-875. DOI:
Ouazene N. 2010. Equilibrium and kinetic modeling of astrazonyellow adsorption by sawdust: effect of important parameters. Int J Chem React Eng. DOI:
Oladipo A A, Gazi M. 2014. ‘Enhanced removal of CV by low cost alginate/acid activated bentonite composite beads; Optimization and modeling using non-linear regressiontechnique’, J. of Wat. Proc. Eng. 2: 43-52. DOI:
Otto CC and Haydel SE. 2013. Microbial clays: composition, activity, mechanisms of action and therapeutic applications, A. Méndez-Vilas, ed. In: Microbial pathogens and strategies for combating them: science, technology and education. Badajoz, Spain: Formatex Research Center. 2: 1169-1180.
Sincero AP and Sincero GA. 2003. Physical-chemical treatment of water and wastewater, IWA Publishing, Londao, USA.
Syafalni, Abdullah R, Abustan I, Ibrahim ANM. 2013. ‘Waste water treatment using bentonite, the combination of bentonitezeolite, bentonite-alum, and bentonite-limestone as adsorbent and coagulant. Int. J Environ. Sci. 4 (3): 2013.
Swartz CD and Ralo T. 2004. Guidelines for planning and design of small water treatment plants for rural communities with specific emphasis on sustainability and community involvement and participation, Silowa Printers, SA.
Tahir SS and Naseem R. 2007. Removal of Cr³ from tannery waste water by adsorption onto bentonite clay. Sep. and Purific. Technol. 53: 312-321
Waanders FB and Brink MC. 2010. The Rehabilitation of Acid Mine Effluents and Toxic Heavy Metal Pollution, emanating from gold mines in South Africa, Proceedings XXV International Minerals processing Conference, IMPC-2010, Brisbane, Australia, 4117-4126.

PlumX Metrics

How to Cite
Ntwampe, O., & Moothi, K. (2018). Investigation of the Effect of a Flocculent of Bentonite Clay with MgCO3 in Synthetic Acid Mine Drainage (AMD) Treatment. Journal of Applied Chemical Sciences, 5(2), 435-444. Retrieved from

Most read articles by the same author(s)

Obs.: This plugin requires at least one statistics/report plugin to be enabled. If your statistics plugins provide more than one metric then please also select a main metric on the admin's site settings page and/or on the journal manager's settings pages.