Development of Low Cost Treatment Options for Arsenic Removal in Water Treatment Facilities

...............................................................................................3 Introduction............................................................................................3 Arsenic Maximum Contaminant Level.............................................................3 Arsenic Speciation...................................................................................4 Concurrent Arsenic and Iron Removal............................................................4 Prior Work in the Area of Oxidation/Coagulation/Filtration for Arsenic Removal.........5 Fenton Process Chemistry..........................................................................5 Project Approach....................................................................................8 Materials and Methods...............................................................................9 Chemicals.............................................................................................9 Analytical Methods..................................................................................9 Arsenic.........................................................................................9 Iron...........................................................................................10 Hydrogen Peroxide........................................................................10 Other Instrumental Measurements......................................................10 Experimental Procedures...........................................................................10 Sample Collection..........................................................................10 Flow Experiments...................................................................................11 Laboratory flow experiments....................................................11 On-site pilot-scale experiments..................................................13 Calculational Methods..............................................................................16 Kinetic Calculations........................................................................16 Equilibrium Calculations..................................................................17 Results and Discussion...........................................................................18 Preliminary Laboratory Experiments.............................................................18 Determination of Rates of Iron Oxidation by Oxygen.................................18 Effect of Hydrogen Peroxide on Iron Oxidation Rate.................................20 Laboratory Flow Experiments.....................................................................26 On-Site Pilot-Scale Flow Experiments...........................................................27 Treatment Cost Estimates..........................................................................33 Conclusions..........................................................................................34 Future Work........................................................................................35 Acknowledgements................................................................................35 Appendix A..........................................................................................36 Appendix B..........................................................................................45 Appendix C..........................................................................................50 References...........................................................................................53