SAFR: Sustainable and Affordable Fluoride Removal

200 million people worldwide are at risk of developing irreversible crippling deformities (e.g., dental/skeletal fluorosis) by drinking groundwater contaminated with toxic levels of naturally-occurring fluoride. Sustainable and Affordable Fluoride Removal (SAFR) is a method for using mildly processed bauxite, an aluminum-rich ore, to remediate groundwater fluoride concentrations to the World Health Organization’s maximum contaminant limit for safe drinking water (1.5 mg F-/L).   

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  • Help us prototype our innovation
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About This Innovation

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Provide a status update for your Innovation.

Sustainable and Affordable Fluoride Removal (SAFR) is an effective, inexpensinve, and sustainable method for remediating excess fluoride in groundwater using mildly processed bauxite. Our latest update is that we have filed a provisional patent for this technology through the Lawrence Berkeley National Laboratory's Innovations and Partnerships (IPO) office and are in the process of applying for numerous grants. So far, approximately $25,000 in grant funding has been raised by the graduate student (Katya Cherukumilli) who initiated this project as part of her dissertation work.

To date, bauxite samples from USA, Ghana, Guinea, and India have all been shown to be effective; studies thus far demonstrate that these globally diverse bauxites can work to remediate field-relevant toxic concentrations of fluoride to below the World Health Organization (WHO) maximum contaminant limit in synthetic and real groundwater (1.5 mg F-/L). We have verified the first-generation prototype performance using groundwater from Nalgonda District and West Bengal, India and are reiterating the prototype based on that information. Samples of synthetic groundwater with high fluoride content reached potable levels after treatment with the SAFR process. Concurrently, in cooperation with local partners in India, project staff is identifying potential sites to pilot future prototypes to bring the product to full scale.   
Initial studies have successfully shown proof of concept inexpensive processing methods (the details of which can be provided after obtaining permission from the legal office owing to Intellectual Property matters).  In these studies, the dispersive batch media (mildly processed bauxite) was added to the groundwater at a certain pH and dose, which were determined based on the specific chemical composition of the bauxite being used and the initial concentration of fluoride in the source water. Based on previous literature on gibbsite, which is the active mineral component of bauxite, we hypothesize that the primary chemical mechanism adsorbing fluoride onto bauxite is the formation of a specific inner sphere complex between aluminum and fluoride, wherein fluoride ions replace hydroxyl groups on the bauxite surface. Our current studies focus on characterizing the various bauxite ores to determine their intrinsic features that control their fluoride removal performance.


How does your innovation work?

The following process is used to remove fluoride from the water using bauxite:
●      Bauxite is mildly processed using proprietary inexpensive methods described in our provisional patent. 
●      A specified dose (g/L) of bauxite calculated to bring fluoride concentrations down to the WHO limit (1.5 mg/L) is added to a batch reactor with groundwater pumped into a tank. This minimum bauxite dose depends on prior measured concentration of fluoride in the source water, as well as the specific bauxite source being used.
●      The bauxite particles are dispersed throughout the tank using motorized paddles. Depending on the bauxite mineralogy and chemical composition, which is influenced by the source, the pH of the mixture may need to be adjusted.
●      The fluoride is adsorbed onto the bauxite particles over a predetermined contact time, after which the mixing is stopped and a coagulant (e.g., alum) is added to aid in the removal of the spent bauxite particles allowing the treated water to be available for consumption.​  Many posttreatment processing options for this are widely available, including (1) allowing the particles to settle and removing them via sludge-outlet on the lower end of the sloping bottom of the tank amd drying the fluoride-laden bauxite sludge; (2) allowing enough contact time between the bauxite and fluoride to allow the adsorption reaction to occur and then passing the water through a rapid sand filter to remove the particles, or (3) using alum or another coagulant to generate larger particles and rapidly settle out the flocs, then removing them. 

What Evidence do you have that your Innovation works?

We have successfully shown experimental proof of concept that the SAFR process works to remediate field-relevant fluoride concentrations (10 mg/L) down to the WHO-MCL (1.5 mg/L) in the presence of coocurring groundwater ions in both synthetic and real groundwater samples. This scientific evidence will be published in the next year in numerous peer-reviewed journal articles. 

With its inception only a few years ago, the SAFR project is still in the initial R&D experimental testing phase. Over the next few years, the fluoride-remediation group at UC Berkeley will expand by adding more technical staff/researchers who will help pilot the innovation at scale (in the field) to demonstrate that the SAFR process can produce inexpensive fuoride-free water in a rural remote setting with locally available material production and processing methods.

Do you have current users or testers?

A final year PhD candidate (Katya Cherukumilli), an undergraduate research assistant, and a postdoctoral researcher are currently testing the SAFR process in lab through batch adsorption and analytical studies at UC Berkeley and the Lawrence Berkeley National Laboratory's Molecular Foundry. 

What is your strategy for expanding use of your innovation?

  • Pilot the SAFR process and conduct willingness to pay studies in Nalgonda District, India, to determine the local pricepoint for the innovation
  • Work with the local district-level public engineering health departments and rural water supply networks in South India (state of Telangana) to spread educational campaigns about the dangers of drinking fluoride contaminated groundwater from wells and inform the village panchayat leaders about the inexpensive SAFR process, which can be implemented at the community scale. 

Next Steps

  1. Conduct household surveys and in-depth focus groups in Nalgonda District, Telangana, India, in order to 1) Identify existing drinking water sources and reliance on fluoride-contaminated borewells and 2) Determine a preference for mode (self-pick up vs. home delivery) and scale (household vs. community) of treatment system
  2. Verify 1st generation prototype’s performance using real groundwater and estimate operating cost in the field (e.g., pumps, electricity, buying local materials to build small scale batch reactor, etc.)
  3. Use water quality measurements and feedback from the field test to build a 2nd generation prototype that takes into account necessary adjustments (or additional treatment) for local groundwater composition (e.g. pH, competing ions, pathogens, natural organic matter, etc.)
  4. Assess competitors by comparing our expected material/operation costs relative to other available market technologies (e.g. activated alumina & reverse osmosis)
  5. Meet local industrial contacts to source bauxite ore from mining sites and obtain access to ball milling and processing technologies in local setting
  6. Give in-person update to existing partners (NGO, District Collectorate’s office, etc.) on technical performance and get feedback on future business partners/models
  7. Continue conversations with potential field community partners to gauge how our product could fit into their technology-agnostic business models 
  8. License technology to chosen field implementation partner and use their help to pilot the final generation prototype in Nalgonda (at a school or village center) to demonstrate a successful 3 month operation of different scales (100L/hr-2000L/hr) of the prototype
  9. To successfully implement the full-scale demonstration plant, collaborate with future business partners to develop educational materials to increase awareness about fluoride contamination. 
  10. Succeeding this initial full-scale pilot, replicate and test the delivery model in the field. Work with future licensed partners and the local Public Health Engineers Department, to obtain permission to sell water and verify that the treated water quality meets IS10500:2012 standards (Indian Drinking Water Quality Standards:

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