Aug 17, 2012

Graduate Student Maps Fluoride Contamination in Rural Ghana

Uses Ultrameter II to determine a cost-effective defluoridation plan using existing capped wells in rural Ghana

The need for safe drinking water in rural Ghana inspired Katherine Alfredo, a graduate student at the University of Texas at Austin to propose a project for a Fulbright Fellowship. The purpose of the fellowship was to map the extent of the fluoride concentration in the Bongo District of the Upper Eastern Region for use by local authorities and eventually use the data collected in the development of a cost-effective defluoridation filter for existing capped wells.

In rural areas, groundwater is plentiful, but natural geographic contamination by inorganic contaminants like iron, manganese and fluoride render government sponsored boreholes useless. Fluoride in the Upper East, Upper West and Northern regions of Ghana often exceeds the general WHO recommended limit of 1.5 mg/liter.

Katherine began her research by observing and recording local water usage habits. She conducted borehole water usage counts on centrally and non-centrally located borehole sites tracking the quantity of water collected daily.  Coupling this data with familial compound water usage surveys she was able to begin understanding the volumetric demand placed on each borehole daily and how that volume translates to the household level.

A one-liter sample of water was retrieved for testing and used for all the water quality tests. An aliquot of the sample water was placed in an Ultrameter II 6P, donated by the Myron L Co., to measure pH, ORP, conductivity, total dissolved solids and temperature.

Conductivity readings from the Ultrameter II will be used to simulate influent water containing excessive levels of fluoride in Katherine's laboratory. Using Bongo as a design test case, Katherine plans to adjust the ionic strength of her synthetic influent to reflect that seen in the Bongo District.

Ultrameter II TDS readings were used as a quality indicator of water as it was dispensed from a borehole. The amount of all dissolved solids is important in determining the potential for interference and competition for adsorption sites on the aluminum adsorbents. Preventing any ions from competing for active sites on alumina surfaces will greatly increase the efficiency of filtration.

ORP readings taken by the Ultrameter II gave a good indicator of the general biological activity in the water. Additional testing was performed using two 2 mL tubes filled with sample water to measure nitrate/nitrite and ammonia using test strips. In another 2 mL tube a 1:1 dilution of the sample was created using distilled water to measure alkalinity using test strips.

Using a 0.45 micron filter, a 30 mL or 60 mL sterile plastic bottle was completely filled for fluoride concentration testing later in the laboratory.

Each capped borehole, new borehole, or nonfunctional borehole that was visited had its corresponding borehole identity recorded in a handheld GPS device. After each governance was covered, eight capped boreholes were chosen for water quality testing to be compared to the nearby functional boreholes.

At the time of Katherine's departure, she had reported the pH and fluoride concentration of each well to the two water and sanitation government agencies in the Bongo area—The Community Water and Sanitation Agency and The Bongo District Assembly Water and Sanitation Team.

Katherine continues to analyze data recorded in Ghana and experiment with cost-effective solutions for fluoride removal in rural communities.