Optimizing Sequestration of Manganese (II) with Sodium Triphosphate A Major Qualifying Project Report Submitted to the Faculty of WORCESTER POLYTECHNIC INSTITUTE In partial fulfillment of the requirements for the Degree of Bachelor of Science By Jessica Coelho Katrina Kucher Aaron Ting Environmental Engineering Civil Engineering Civil Engineering Date: March 9, 2008 Approved Professor John Bergendahl Table of Contents Table of Figures....................................................................................................................................................................................... i Table of Tables ....................................................................................................................................................................................... ii Executive Summary ................................................................................................................................................................................ i MQP Design Requirement ................................................................................................................................................................... ii 1 Introduction .............................................................................................................................................................................. 1 2 Background ............................................................................................................................................................................... 3 2.1 Water Chemistry ................................................................................................................................................................... 3 2.1.1 Ligands .......................................................................................................................................................... 4 2.1.1.1 Polyphosphates ............................................................................................................................................. 4 2.1.2 Metal Complexes ........................................................................................................................................... 6 2.1.3 Bonding Mechanisms .................................................................................................................................... 6 2.1.4 Precipitation versus Sequestration ............................................................................................................... 7 2.2 Manganese ............................................................................................................................................................................ 8 2.2.1 Chemical Structure ....................................................................................................................................... 9 2.2.2 Environmental Concerns Associated with Manganese ............................................................................... 10 2.2.3 Conventional Manganese Removal Methods .............................................................................................. 11 2.3 Sequestering using a Polyphosphate .................................................................................................................................. 13 2.3.1 Polyphosphate Reactions with Manganese (II) .......................................................................................... 14 2.3.2 Polyphosphate Reactions with Other Metals .............................................................................................. 16 2.3.3 Additional Issues Surrounding Polyphosphate Sequestering ..................................................................... 17 2.4 West Boylston Drinking Water Facility .............................................................................................................................. 18 2.4.1 West Boylston Drinking Water Distribution ............................................................................................... 18 2.4.2 Common Constituents in West Boylston Drinking Water ........................................................................... 18 2.4.3 Federal & State Regulations for Water Quality at West Boylston .............................................................. 20 2.4.4 Water Treatment Methods Employed by West Boylston ............................................................................ 20 2.5 Previous Experimentation to Alleviate Manganese Precipitation at the West Boylston Drinking Water Facility............ 21 2.6 Background Summary ........................................................................................................................................................ 21 3 Methodology ............................................................................................................................................................................ 22 3.1 Stock Solutions .................................................................................................................................................................... 22 3.2 Calibration of Analyzing Apparatuses ................................................................................................................................ 25 3.3 Manganese Precipitation Using Ozone ............................................................................................................................... 26 3.4 Preliminary Sequestration experiments using Sodium Triphosphate................................................................................ 27 3.5 Residence Time for Proper Sequestering of Mn using Na5(P3O10) ...................................................................................... 28 3.6 Optimizing pH for Sequestering Mn Using Na5(P3O10) ....................................................................................................... 30 3.7 Effect of Competing Metals on Na5(P3O10) and Sequestering Mn ....................................................................................... 31 3.8 Alternative Sequestering Agents ........................................................................................................................................ 31 4 Analysis & Results ................................................................................................................................................................... 32 4.1 Manganese Precipitation .................................................................................................................................................... 32 4.2 Sequestration ...................................................................................................................................................................... 34 4.3 Detention Time of Triphosphate & Manganese .................................................................................................................. 35 4.4 pH ........................................................................................................................................................................................ 40 4.5 Alternative Polyphosphate Chemicals ................................................................................................................................ 42 5 Triphosphate Dosing Design: West Boylston ...................................................................................................................... 44 5.1 Problem ............................................................................................................................................................................... 44 5.2 Laboratory Experimentation .............................................................................................................................................. 44 5.3 Application of Data ............................................................................................................................................................. 45 5.4 Barriers of Deployment ....................................................................................................................................................... 46 6 Recommendations .................................................................................................................................................................. 48 6.1 Sequestration of Manganese ............................................................................................................................................... 49 6.2 Future Work for West Boylston Drinking Water Facility ................................................................................................... 49 6.3 Other Water Treatment Facilities ...................................................................................................................................... 50 6.4 Future Analysis of Polyphosphate Sequestering ................................................................................................................. 50 6.4.1 Proposed Future West Boylston Drinking Water Experimentation ........................................................... 51 7 Conclusion ................................................................................................................................................................................ 52 8 References ...............................................................................................................................................................................