Fluoride, DBP Precursors, and Particles: Simultaneous Removal with Aluminum Salts A Solution for Small Drinking Water Systems

EPA Grant Number: R835176
Title: Fluoride, DBP Precursors, and Particles: Simultaneous Removal with Aluminum Salts A Solution for Small Drinking Water Systems
Investigators: Lawler, Desmond , Katz, Lynn
Institution: The University of Texas at Austin
EPA Project Officer: Page, Angela
Project Period: December 1, 2011 through November 30, 2014 (Extended to June 19, 2016)
Project Amount: $499,357
RFA: Research and Demonstration of Innovative Drinking Water Treatment Technologies in Small Systems (2011) RFA Text |  Recipients Lists
Research Category: Drinking Water , Water


In January 2011, EPA finalized the risk and exposure assessments for fluoride and announced that it would review the drinking water regulations for fluoride due to concerns associated with dental and skeletal fluorosis. Many utilities currently unconcerned with the presence of naturally occurring fluoride in their water will suddenly face problems meeting a lower standard, and other systems using a water blending approach to meet existing standards will have to reconsider their current strategy. Irrespective of potential future regulations, some SWS already struggle to meet the current regulations. Adsorption and/or co-precipitation to aluminum are potentially viable approaches for meeting these new standards and alum coagulation is considered a conventional treatment techno logy for removal of particles from drinking water sources. Moreover, enhanced alum coagulation which requires high concentrations of aluminum added to the process has been shown to be effective for removal of DBP precursors: namely, natural organic matter (NOM). Unfortunately, the presence of fluoride may interfere with the formation of aluminum hydroxide precipitates and interrelationships among NOM, aluminum precipitation and fluoride removal are not well understood. The goals of this project are to (1) develop a treatment system for the simultaneous removal of fluoride, natural organic matter (NOM). and particles from natural waters that are used as drinking water sources. and (2) demonstrate the efficacy of the system through small-scale pilot testing of a continuous flow system using a real drinking water source. The system will be specifically designed for small water systems (SWS) in recognizing the limited capital and personnel resources available. The treatment system will exploit favorable interactions of all three contaminants with aluminum (oxy)hydroxides in an enhanced coagulation process for removal of turbidity, NOM and fluoride.

Expected Results:

The research plan will be conducted in three phases that include:

  1. Develop a mechanistic understanding of the interactions among fluoride. organic ligands and aluminum during enhanced coagulation processes
  2. Apply this mechanistic understanding to waters containing natural organic matter for a range of values, PACI, and alum concentrations, NOM concentrations, and NOM sources to verify, the mechanistic interpretation developed within Phase I and develop a set of guidelines for implementation of enhanced coagulation processes for simultaneous fluoride and NOM removal
  3. Conduct pilot test at two different sites using conditions determined from recommendations with PACI and Alum to validate the guidelines

The results of this research will provide a set of validated guidelines for the implementation of enhanced alum coagulation for simultaneous removal of NOM and fluoride. These guidelines will be available to practitioners. academicians and government agencies interested in treatment. process development, and regulatory guidance.