Sustainable water purification in Ghana (Summer 2016)

I had the opportunity to participate in an international research experience for students (IRES), which is sponsored by the National Science Foundation (Award #1358204 ). This program was carried out through Southern University and A&M College in partnership with the Kwame Nkrumah University of Science and Technology (KNUST), located in Baton Rouge, Louisiana and Kumasi, Ghana, respectively. 

Water collected from a borehole in the Bongo District.

Water collected from a borehole in the Bongo District.

Motivation

  • Elevated levels of fluoride (up to 4.60 mg/L) and frequent cases of dental and skeletal fluorosis among children have been reported in the Bongo District, which is located in the Upper East region of Ghana (Apambire, Boyle, & Michel, 1997)
  • Prolonged exposure to fluoride can lead to dental and skeletal fluorosis (Bhatnagar, Kumar, & Sillanp, 2011)
  • Controlling excess fluoride in the drinking water of developing countries is challenging due to the unavailability of advance defluoridation (i.e. fluoride removal) techniques (Craig, Stillings, Decker, & Thomas, 2015)
  • Treatment for dental fluorosis are costly for developing communities and there is no established treatment for skeletal fluorosis - Prevention is Key! (Sherwood, 2010; Whyte, Essmyer, Gannon, & Reinus, 2005)
  • It is vital to create sustainable and low cost methods of purifying fluoride from water to permissible levels (between 0.5 - 1.5 mg/L, World Health Organization) (Gorchev & Ozolins, 2011)

Laterite as a potential adsorbent material for fluoride removal

Preparing a laterite - alumina composite with my lab partner Eric Thompson, Jr. at the KNUST materials laboratory.

Preparing a laterite - alumina composite with my lab partner Eric Thompson, Jr. at the KNUST materials laboratory.

Laterite is a local resource found abundantly within the Bongo District. It is a soil that arises from the natural weathering of rocks. Previous research by Osei and colleagues has investigated the use of heat activated laterite as an adsorbent of fluoride. Although the performance of the heat activated laterite improved (compared to the raw laterite), fluoride uptake did not fall below 1.5 mg/L (Osei, Gawu, Schäfer, Atipoka, & Momade, 2016). 

Measuring the pH and fluoride concentration of effluents collected during the column adsorption experiments at the KNUST lab. 

Measuring the pH and fluoride concentration of effluents collected during the column adsorption experiments at the KNUST lab. 

The aim for our investigation was to enhance laterite in absorbing fluoride to permissible levels. In doing so, we combined laterite and alumina (Al2O3) to form a laterite - alumina composite and activated the mixture with intense heat. Previous research has reported that activated alumina has been sufficient for reducing fluoride concentrations  (Bhatnagar et al., 2011). Because of this, it was hypothesized that using an activated laterite - alumina will increase fluoride uptake and thus performance. 

Laterite - alumina composites were prepared using soil samples collected from the Bongo District. The prepared composites were utilized in column adsorption experiments for assessing their defluoridation capacities. Our investigation revealed that all of the laterite - alumina composites were successful in reducing the fluoride concentration below 1.5 mg/L. However, the observed bed volumes (i.e. the total volume of composite required for adsorbing fluoride to 1.5 mg/L) were too low and therefore the application of the composites was not feasible. Strategies for increasing the bed volumes are necessary for improving the composites for future implementation. 

Presentations & other activities

Use of laterite-alumina composite as a sustainable means of fluoride removal from drinking water [Talk]. AAAS Emerging Researchers National (ERN) conference in STEM, 2017. 

Won second place for my oral presentation at the 2017 AAAS ERN Conference (technology and engineering category). Photo credit: Colella Digital. 

Won second place for my oral presentation at the 2017 AAAS ERN Conference (technology and engineering category). Photo credit: Colella Digital. 

Bringing Back the Smiles of the Bongo District [Talk]. Living Marine Sciences Cooperative Science Center (LMRCSC) Research Symposium, 2016.

Using laterite-alumina composites for adsorbing fluoride [Talk]. Southern University and A&M College International Research Experience for Students (SU-IRES) Research Symposium, 2016. 

References

Apambire, W. B., Boyle, D. R., & Michel, F. A. (1997). Geochemistry, genesis, and health implications of fluoriferous groundwaters in the upper regions of Ghana. Environmental Geology, 33(1), 13–24. http://doi.org/10.1007/s002540050221

Bhatnagar, A., Kumar, E., & Sillanp, M. (2011). Fluoride removal from water by adsorption-A review. Chemical Engineering Journal. http://doi.org/10.1016/j.cej.2011.05.028

Craig, L., Stillings, L. L., Decker, D. L., & Thomas, J. M. (2015). Comparing activated alumina with indigenous laterite and bauxite as potential sorbents for removing fluoride from drinking water in Ghana. Applied Geochemistry, 56, 50–66. http://doi.org/10.1016/j.apgeochem.2015.02.004

Gorchev, H. G., & Ozolins, G. (2011). WHO guidelines for drinking-water quality. WHO Chronicle, 38(3), 104–108. http://doi.org/10.1016/S1462-0758(00)00006-6

Osei, J., Gawu, S. K., Schäfer, A. I., Atipoka, F. A., & Momade, F. W. (2016). Impact of laterite characteristics on fluoride removal from water. Journal of Chemical Technology and Biotechnology, 91(4), 911–920. http://doi.org/10.1002/jctb.4656

Sherwood, I. A. (2010). Fluorosis varied treatment options. Journal of Conservative Dentistry : JCD, 13(1), 47–53. http://doi.org/10.4103/0972-0707.6263