Final Pilot Testing Report - Minnesota Legislature 2013f.pdf Pilot testing commenced in May 2012 and

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  • Final Pilot Testing Report

    Plant Site Wastewater Treatment Plant Pilot Testing Program

    Prepared for Poly Met Mining Inc. January 2013

  • Final Pilot Testing Report

    Plant Site Wastewater Treatment Plant Pilot Testing Program

    Prepared for Poly Met Mining Inc. January 2013

    4700 West 77 th

    Street Minneapolis, MN 55435-4803 Phone: (952) 832-2600 Fax: (952) 832-2601

  • P:\Mpls\23 MN\69\2369C08 NorthMet WWTF\WorkFiles\PS WWTF Pilot Testing\Reports\Final Report\Pilot Testing Report v1

    25JAN2013.docx i

    Final Pilot Testing Report Plant Site Wastewater Treatment Plant Pilot Testing Program

    January 2013

    Table of Contents

    Executive Summary ....................................................................................................................................... i

    1.0 Introduction ............................................................................................................................................ 4

    2.0 Testing Program Structure ...................................................................................................................... 6

    2.1 Pilot Test Program Overview ...................................................................................................... 6

    2.1.1 Phase 1 – Well Testing .................................................................................................. 6

    2.1.2 Phase 2 – Startup and Commissioning ........................................................................... 6

    2.1.3 Phase 3 – Membrane Selection, Pretreatment Investigations, and System Optimization7

    2.1.4 Phase 4 – Steady-State Operation .................................................................................. 7

    2.1.5 Phase 5 – Concentrate Volume Reduction Investigation ............................................... 7

    2.1.6 Phase 6 – Effluent Stabilization Investigation ............................................................... 7

    2.1.7 Phase 7 – Membrane Fouling ........................................................................................ 7

    2.1.8 Supplemental Testing ..................................................................................................... 8

    2.1.9 Testing Facilities ............................................................................................................ 8

    2.1.10 Roles .............................................................................................................................. 8

    2.1.10.1 PolyMet ........................................................................................................... 8

    2.1.10.2 Barr Engineering ............................................................................................. 8

    2.1.10.3 Equipment Suppliers ....................................................................................... 9

    2.1.10.4 Laboratories ..................................................................................................... 9

    3.0 Water Quality ....................................................................................................................................... 11

    3.1 Influent Water Quality .............................................................................................................. 11

    3.2 Treated Water Quality Targets .................................................................................................. 11

    4.0 Reverse Osmosis Pilot Test Results ..................................................................................................... 12

    4.1 Pretreatment .............................................................................................................................. 12

    4.1.1 Filter Loading............................................................................................................... 12

    4.1.2 Filter Removal Rates .................................................................................................... 12

    4.1.3 Residuals ...................................................................................................................... 13

    4.1.4 Discussion .................................................................................................................... 13

    4.2 Reverse Osmosis ....................................................................................................................... 14

    4.2.1 Flux and Recovery ....................................................................................................... 14

    4.2.2 Permeate Water Quality ............................................................................................... 15

    4.2.2.1 Removal Rates............................................................................................... 15

    4.2.2.2 Comparison to Equipment Supplier Model ................................................... 16

    4.2.3 Cleaning Requirements ................................................................................................ 17

  • ii

    4.2.4 Discussion .................................................................................................................... 17

    5.0 VSEP Pilot Test Results ....................................................................................................................... 19

    5.1 Pretreatment and Optimization ................................................................................................. 19

    5.1.1 Operational Mode ........................................................................................................ 19

    5.1.2 Chemical Pretreatment ................................................................................................. 20

    5.1.2.1 Acid Type ...................................................................................................... 20

    5.1.2.2 pH Adjustment Method ................................................................................. 21

    5.1.2.3 Degree of pH Adjustment ............................................................................. 21

    5.1.3 Recovery ...................................................................................................................... 22

    5.1.4 Cleaning ....................................................................................................................... 22

    5.2 Removal Rates .......................................................................................................................... 23

    5.3 Discussion ................................................................................................................................. 25

    6.0 Effluent Stabilization Bench Test Results ............................................................................................ 26

    6.1 Overview ................................................................................................................................... 26

    6.2 Lime Addition Bench Test ........................................................................................................ 27

    6.2.1 Experimental Setup ...................................................................................................... 27

    6.2.2 Results .......................................................................................................................... 27

    6.2.2.1 Stabilized Water Chemistry........................................................................... 27

    6.2.2.2 Whole Effluent Toxicity ................................................................................ 28

    6.2.3 Implementation Considerations ................................................................................... 28

    6.3 Limestone Bed Contactor Bench Test ...................................................................................... 30

    6.3.1 Experimental Setup ...................................................................................................... 30

    6.3.2 Results .......................................................................................................................... 31

    6.3.2.1 Stabilized Water Chemistry........................................................................... 31

    6.3.2.2 Whole Effluent Toxicity ................................................................................ 31

    6.3.3 Implementation Considerations ................................................................................... 31

    6.4 Discussion ................................................................................................................................. 32

    7.0 Metals Seeding and Arsenic Removal Tests ........................................................................................ 34

    7.1 Overview ................................................................................................................................... 34

    7.2 Methodology ............................................................................................................................. 35

    7.2.1 Metals Seeding Test ..................................................................................................... 35

    7.2.2 Arsenic Removal Test ...................................................................................