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in mg/L. Columns have volumes of 34.9 and 7.9 cm3 and average particlesizes of 637 and 302 µm , for large and small scale respectively. Startingconcentration and flow rate were equivalent for both at 8.6 mg/L fluorideand 1.2 ml/min 945.1Results of batch isotherms showing the fluoride removal capacities ofuntreated wood char and metal oxide amended wood chars. Qe, the mg offluoride removed per gram of media is plotted against Ce, the equilibriumconcentration of fluoride in mg/L .1155.2Results of batch isotherms showing the fluoride removal capacities ofuntreated wood char and metal oxide amended wood chars with andwithout pretreatment (KM potassium permanganate, HP hydrogenperoxide). Figure 5.2A shows results of wood char treated with aluminumsulfate and Figure 5.2B shows results of wood char treated with iron (III)chloride. Qe, the mg of fluoride removed per gram of media is plottedagainst Ce, the equilibrium concentration of fluoride in mg/L .117-1185.3Results of material analysis where 5.3A shows metal loading percentages,5.3B shows point of zero charge values and 5.3C shows specific surfacearea data. Numbers above the bars in each graph note the Qe1.5 values forthat media . 122-1235.4Data shows the fluoride removal capacities of untreated wood char andmetal oxide amended wood chars (WC), with and without pretreatment,(KM potassium permanganate, HP hydrogen peroxide) normalized bymetal content. 5.4A shows results of wood char treated with aluminumxiii

sulfate, 5.4B shows wood char treated with aluminum chloride, 5.4Cshows wood char treated with iron (III) nitrate with the inset graph showingthe data only up to Ce 5 and 5.4D shows wood char treated withiron (II) chloride. The y-axis shows, Qe/metal %, the mg of fluoride removedper gram of media normalized by metal content, and is plotted against Ce,the equilibrium concentration of fluoride in mg/L . .127-1295.5Results of batch isotherms showing the fluoride removal capacities ofuntreated wood char and metal oxide amended wood chars normalized byboth specific surface area and metal content. Qe, the mg of fluorideremoved per gram of media is normalized by specific surface areaand metals content (mg fluoride * g char/g metal * m2) and plottedagainst Ce, the equilibrium concentration of fluoride in mg/L .134A-1Graph shows adsorption isotherms of fluoride removal by Ximeniaamericana (XA) and Eucalyptus robusta (EU) wood chars amendedwith aluminum oxides, plotting fluoride levels adsorbed by the chars(Qe, mg fluoride/g wood char) versus equilibrated aqueousfluoride concentration (Ce, mg/L) . 149A-2Graph shows adsorption isotherms of fluoride removal by fish andbone chars and aluminum oxide amended fish and bone chars, plottingfluoride levels adsorbed by the chars (Qe, mg fluoride/g wood char)versus equilibrated aqueous fluoride concentration (Ce, mg/L) .150B-1Adsorption isotherms of fluoride on fish bone char (FBC), withcompeting ions sulfate (SO4) and phosphate (PO4) present in somexiv

systems as noted in the legend. The y-axis shows fluoride levelsadsorbed by the fish bone char (Qe, mg fluoride/g fish bone char) andthe x-axis shows equilibrated aqueous fluoride concentration (Ce, mg/L) .151.xv

AbstractHuman consumption of unsafe drinking water from an unimproved source is aglobal issue affecting approximately 748 million people worldwide. While this numberhas been decreasing in recent years, an additional 1.2 billion people are estimated tolack access to water that is consistently free from health risks. This dissertation beginswith a literature review investigating drinking water improvement initiatives around theworld and a discussion of reasons why these initiatives often fail. Resources areprovided for researchers and practitioners working on drinking water treatmentimplementations and examples of implementations that have failed or succeeded arediscussed. The conclusion from this review is that global drinking water solutions willbe more effective when designed and implemented by personnel from multipledisciplines.For example, people in several fields, including: social sciences,engineering and business, should collaborate and share ideas and expertise. Ideally thiscollaboration should start at the genesis of a project and continue throughimplementation and follow up.There is hope that the synergistic efforts ofmultidisciplinary teams will help to increase the number of successful water initiatives.Next the dissertation focuses on the problem of elevated fluoride concentrationsin drinking water. Naturally occurring fluoride is the second largest issue contributingto the global water crisis. It is estimated that globally over 200 million people areaffected by elevated concentrations of fluoride in drinking water. The goal of thetechnical portion of this dissertation is to investigate locally available and sustainablematerials that can be used to remove fluoride from drinking water, with a focus onEthiopia and eastern Sub-Saharan Africa. Bone char is very effective as an adsorptivexvi

material, but is not always accepted by communities due to religious or cultural beliefs.Therefore, this research evaluated methods to improve the fluoride removal capacity ofbone char as well as investigated materials that might serve as a replacement for bonechar in appropriate communities. Eucalyptus trees are prevalent in Ethiopia where alarge fluoride problem exists, and thus, eucalyptus wood char was investigated as apotential substitute for bone char. This dissertation studied wood char produced fromEucalyptus robusta as an adsorption material to remove fluoride from water, therebymaking it safe for consumption. Although the use of eucalyptus wood char aloneremoved minimal fluoride, when it was amended with aluminum and iron oxides itevidenced much higher fluoride removal capacities. Metal oxides, produced fromstarting materials such as aluminum sulfate and iron (III) nitrate, were used to amendthe wood char. Metal amendments resulted in fluoride removal capacities ranging from3 to 50 times higher than wood char without amendment. The combination of woodchar and metal oxide amendment is synergistic because the wood char provides a matrixwith a high specific surface area for the metal oxides to adhere to while the metal oxideamendment increases the electrostatic attraction of the char surface for fluoride.Additionally, wood char was pretreated with oxidizing agents such as hydrogenperoxide and potassium permanganate prior to metal amendment. These pretreated andmetal amended chars were found, in most cases, to have increased metal loading ratesand, in some cases, higher fluoride removal capacities.This dissertation also looked at ways to improve the adsorption effectiveness ofbone char for communities where bone char is an acceptable material for drinking watertreatment. Amending bone char with aluminum nitrate showed an increase in fluoridexvii

removal at high equilibrium concentrations but not at low equilibrium concentrationsclose to the WHO recommended value for fluoride (1.5 mg/L). Select fluoride removalmaterials, including aluminum impregnated wood char, activated alumina, bone charand aluminum amended bone char, were studied in the field using groundwater from awell in a rural Ethiopian community. Field results suggested that the combination ofelevated groundwater pH along with competing ions such as sulfate (both common inground waters of the Ethiopian Rift Valley) affected the fluoride removal capacities ofthe materials studied, particularly the aluminum impregnated wood char. Finally, thisresearch tested the validity of the Rapid Small Scale Column Tests (RSSCT) principlesfor bone char adsorbing fluoride from water. These experiments indicated that RSSCTprinciples are applicable for bone char; use of this approach can result in large time andcost savings to researchers and implementers. Overall, this dissertation provides severalconclusions that are practically helpful to researchers in the field and also foundationalresearch on which future studies can build to continue efforts to find sustainable andappropriate fluoride removal technologies.xviii

CHAPTER 1IntroductionSafe Drinking Water and FluorideLack of safe drinking water is a key global issue. The World HealthOrganization (WHO) and the United Nations International Children’s Emergency Fund(UNICEF) estimate that 748 million people currently lack access to an improved watersource (WHO and UNICEF, 2014). Onda et al. (2012) suggested that in addition to the748 million people without an improved water source, another 1.2 billion people maybe consuming water from sources that are improved but still at risk for microbialcontamination. Lack of safe water is further exacerbated by the reality that 1.4 billionpeople are estimated to live on less than 1.25 (US) per day (Chen and Ravallion,2008). In addition, water-related health issues contribute to concerns such as lack ofeducation, gender equity and economic development. To mitigate these drinking waterissues, sustainable, inexpensive and locally available water treatment technologies mustbe developed, improved and implemented.After pathogens, the largest issue contributing to lack of safe drinking water isnaturally occurring fluoride, which is estimated to affect 200 million people globally(Amini et al., 2008). The WHO recommended fluoride limit in drinking water is 1.5mg/L (World Health Organization, 2011). Fluoride is naturally occurring in thegroundwater of many areas of the world including: the Rift Valley of Africa, portions ofChina and India and parts of the southwestern United States (Brindha et al., 2010;Fewtrell et al., 2006; Meenakshi and Maheshwari, 2006; Nigussie et al., 2007).1

Although fluoride is naturally occurring in groundwater, it can also occur due toanthropogenic processes such as aluminum smelting and fertilizer production (Hem,1985; Hudak, 2008). Fluoride is an example of an element where the dose consumeddetermines whether it is beneficial or toxic. In low doses fluoride helps to preventdental carries and, thus, improves the health of teeth (Fawell et al., 2006; Schamschulaand Barmes, 1981). However, consumption of higher concentrations can be harmful asit causes dental and skeletal fluorosis (Fawell et al., 2006; Gazzano et al., 2010). Dentalfluorosis results in darkening or mottling of teeth, which, while not physicallydebilitating, can cause social and financial issues due to the stigma of mottled teeth.Skeletal fluorosis can cause bones to become deformed or stiff which can limit mobilityand/or cause pain (Kaseva, 2006; Meenakshi and Maheshwari, 2006). Therefore, manyresearchers are investigating fluoride removal technologies (Abe et al., 2004; Ayoob etal., 2008; Gwala et al., 2011; Nigussie et al., 2007).Fluoride Removal TechnologiesWater treatment methods frequently investigated for fluoride removal include:precipitation, ion exchange, electrocoagulation, and adsorption (Brunson and Sabatini,2009; Gwala et al., 2011; Kamble et al., 2007; Meenakshi and Maheshwari, 2006; Rao,2003; Tchomgui-Kamga et al., 2010). For rural regions in developing countries,techniques should be inexpensive, sustainable and use locally available materials fortreating water containing high concentrations of fluoride. The Nalgonda techniqueutilizes alum and lime to produce aluminum oxide precipitates that sorb and settlefluoride ions. This technique is popular because of its low cost and use of chemicals that2

are easily obtained. However, the Nalgonda technique requires frequent addition ofchemicals, produces copious amounts of waste sludge, and is not efficient for fluorideremoval when the starting concentration is high (Fawell et al., 2006; Nigussie et al.,2007). While electrocoagulation can effectively remove fluoride, it requires some formof electricity (Gwala et al., 2011). Activated alumina is an adsorptive materialfrequently used in filtration systems. Adsorption can be helpful for fluoride removalbecause it operates using gravity flow, and, depending on the sorptive material, can beeffective at treating water to meet the WHO fluoride standard. Activated alumina can beeffective, but is a manufactured material that may be prohibitively expensive to obtainin rural developing regions. Therefore, research evaluating less expensive and locallyavailable adsorptive materials is desirable in an effort to respond to the limitations oftechniques discussed above.Bone char has been widely investigated as an adsorptive material for removal offluoride and several trace metals (Bhargava and Killedar, 1991; Kaseva, 2006; Larsen etal., 1994; Thomson et al., 2003). Bone char is primarily composed of hydroxyapatite(70-76%) and carbon (8-11%) and is currently produced in several developing countriesfrom waste bones, which makes it relatively inexpensive (Medellin-Castillo et al., 2007;Müller, 2007; Purevsuren et al., 2004; Wilson et al., 2003). Charring animal bonesremoves organic matter from the bone structure, producing a large specific surface areawhich is helpful for high adsorption capacity (Chidambaram et al., 2004; Kaseva,2006). For example, Medellin-Castillo et al. (2007) reported a specific surface area of104 m2/g for their tested bone char. This is similar to levels reported by others, such as150 m2/g (Chen et al., 2008) and 105 m2/g (Brunson and Sabatini, 2009). Variations in3

specific surface area can be attributed to char source, type of bones and preparationmethod. Bone char also exhibits favorable surface chemistry with Medellin-Castillo etal. (2007) and Brunson and Sabatini (2009) both finding the point of zero charge(pHPZC) of bone char to be close to 8.3. In solutions with pH values below the pHPZC, thebone char surface will exhibit a positive charge, while at solution pH values above thepHPZC the material will exhibit a negative charge. Thus, for fluoride removal occurringin groundwater with near neutral pH values, a material with a high pHPZC will evidencea positive surface charge which will attract negatively charged fluoride ions. Despite itsfavorable surface chemistry and effective fluoride removal, bone char is not accepted insome communities due to religious and cultural reasons or poor quality of charproduction (Fawell et al., 2006), leading to the need for alternate materials.New research investigating the potential for using a carbon-based material, suchas wood char, as an adsorption material is helpful for locations where bone char is notaccepted. Wood is typically composed of carbon (50%), oxygen (44%), hydrogen (6%)and trace amounts of metals (Pettersen, 1984; Rowe and Conner, 1979). However, thechemical composition and other characteristics of wood can vary based on location, soiltype, season, age and type of wood (Pettersen, 1984). The specific surface area of woodchar is shown to differ greatly depending on charring conditions, wood type andlocation of wood growth. For example, James et al. (2005) showed wide ranges ofspecific surface area for wood chars produced in laboratory conditions, ranging from1.0 to 397 m2/g, and different kinds of wood charred in nature, ranging from 1.7 to 85m2/g. Although wood char in some cases exhibits a high surface area, a study by Abe etal. (2004) showed that bone char has a much higher fluoride removal capacity than4

several tested wood chars. Therefore, methods are needed to improve the fluorideremoval capacity of wood chars.Metal amendments have shown promise as one way to improve the fluorideremoval capacity of wood chars. For example, studies have shown promising results forremoving fluoride with aluminum or iron-based precipitates.Levya-Ramos et al.(1999) found that impregnating activated carbon with aluminum greatly improved thefluoride removal capacity. A material produced from aluminum and iron was studiedby Biswas et al. (2007) and results showed a maximum removal value of 18 mg offluoride removed per g of material as calculated by the Langmuir equation. The successof fluoride adsorption by metal amendments is attributed to the attraction between thenegatively charged fluoride ions and the positively charged metal oxide surfaces,resulting in ion exchange between fluoride and hydroxide ions on the material surface.While bone char has previously shown a high fluoride removal capacity, it is notreaching the removal effectiveness of some of the aluminum/iron based materialsdiscussed above, which means it may be useful to investigate ways of enhancingfluoride uptake with bone char.A final approach of interest is pretreating charred media with either oxidizing orreducing agents to alter their surface chemistry. Pretreatment methods could beinvaluable for their effects on surface chemistry. Polovina et al. (1997) suggested this isone of the most important aspects of an adsorption material. There are several potentialeffects of pretreating char media. One is that pretreatment of media with reducingagents may remove some acidic functional groups from the surface of the materials,which would increase the basicity of the media and, thus, increase the pHPZC values.5

This change in pHPZC should increase the attraction between the media and fluoride ionswithout the requirement of metal amendments. Minimal work has been done in thisarea.One study was conducted where activated carbon was treated with ironammonium sulfate and sodium dithionite to enhance removal of hexavalent chromiumfrom water. While the study by Han et al. (2000) did not show success with increasedhexavalent chromium removal, their preliminary work laid the foundation for thecurrent research seeking to enhance fluoride removal. A se

Dr. David A. Sabatini, Chair . Susan Williams and Audre Carter in the College of Engineering. The work done in rural Ethiopia could not have been done without the generous help of . without pretreatment (KM potassium permanganate, HP hydrogen peroxide). Fig