engineered wetland-phosphex integration project … documents/reports... · 6.1 feed for the phase...

REPORT

to

LAKE SIMCOE REGION CONSERVATION AUTHORITY

for

ENGINEERED WETLAND-PHOSPHEX INTEGRATION PROJECT

ADVANCED ENGINEERED WETLANDS PROCESS TO REMOVE NUTRIENTS AND OTHER CONTAMINANTS FROM

WASTEWATERS AND STORMWATERS IN THE LAKE SIMCOE AREA

PHASE 1 TREATABILITY TESTING VOLUME 2 - APPENDICES

PROJECT 1221 10066

Prepared By

Stantec Consulting 7070 Mississauga Road

Mississauga, ON L5N 7G2 Tel: (905) 817-2079 Fax: (905) 858-4426

September, 2010

EW-Phosphex Project, Phase 1, Project 1221 10066/7 © Stantec, 2010

i

TABLE OF CONTENTS FOR VOLUME 1 VOLUME 1 OF THIS REPORT IS BOUND SEPARATELY

1. INTRODUCTION

1.1 Background 1.2 Engineered Wetlands 1.3 The Phosphex™ Technology 1.4 The EW-Phosphex Project 1.5 Phase 1A Pilot Testing 1.6 Phase 1B Demonstration Testing 1.7 Phase 2 Field Testing 1.8 This Report

2. SCOPE OF PHASE 1A

2.1 The Phase 1A Pilot Unit 2.2 The Phase 1B Demonstration Unit 2.3 Objectives of Phase 1A Pilot Testing 2.4 Objectives of Phase 1B Demonstration Testing

3. DESIGN AND CONSTRUCTION OF THE PHASE 1A PILOT UNIT

3.1 Phase 1A Pilot Unit Layout 3.2 Phase 1A Pilot Unit Mixing Tank 3.3 Phase 1A Pilot Unit Aerated Cell 3.4 Phase 1A Pilot Unit Phosphex Cell 3.5 Phase 1A Pilot Unit Open Tank Cell 3.6 Phase 1A Pilot Unit Polishing Cell

4. DESIGN AND MODIFICATION OF THE PHASE 1B DEMONSTRATION UNIT

4.1 Phase 1B Demonstration Unit Layout

4.2 Phase 1B HSSF CW Cell 4.3 Phase 1B Aerated VSSF EW Cell 4.4 Phase 1B Phosphex Cell 4.4 Phase 1B CO2 Addition Tanks

5. OPERATION OF THE PHASE 1A PILOT UNIT

5.1 Feed for the Phase 1A Pilot Unit 5.2 Schedule for Phase 1A Pilot Unit Operations 5.3 Phase 1A Pilot Unit Operations

6. OPERATION OF THE PHASE 1B DEMONSTRATION UNIT

6.1 Feed for the Phase 1B Demonstration Unit 6.2 Schedule for Phase 1B Demonstration Unit Operations 6.3 Phase 1B Demonstration Unit Operations 7. ANALYTICAL TESTING & METHODOLOGY 7.1 Phase 1 Monitoring 7.2 Sampling Carried Out 7.3 Analytrical Test Procedures carried Out by CAWT 7.4 Analytrical Test Procedures carried Out by UofW

8. DISCUSSION OF PHASE 1A PILOT UNIT RESULTS


ii

8.1 General 8.2 Total Phosphorus Removal during Phase 1A 8.3 Ortho-Phosphate Removal during Phase 1A 8.4 pH and Alkalinity during Phase 1A 8.5 Dissolved Oxygen during Phase 1A 8.6 Conductivity during Phase 1A 8.7 cBOD and COD during Phase 1A 8.8 Ammonia Nitrogen and Nitrate Nitrogen during Phase 1A 8.9 Pathogen Indicators during Phase 1A 8.10 Metals during Phase 1A

8.11 Temperature during Phase 1A 8.12 Opening of the Phase 1A Phosphex Cell 8.13 Summary of Results for Phase 1A

9. DISCUSSION OF PHASE 1B DEMONSTRATION UNIT RESULTS

9.1 General 9.2 Total Phosphorus Removal during Phase 1B 9.3 Ortho-Phosphate Removal during Phase 1B 9.4 pH and Alkalinity during Phase 1B 9.5 Dissolved Oxygen during Phase 1B 9.6 Conductivity during Phase 1B 9.7 cBOD and COD during Phase 1B 9.8 Ammonia Nitrogen and Nitrate Nitrogen during Phase 1B 9.9 Pathogen Indicators during Phase 1B 9.10 Metals during Phase 1B 9.11 Temperature during Phase 1B 9.12 Summary of Results for Phase 1B

10. CONCLUSIONS AND RECOMMENDATIONS

11. CLOSURE


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TABLE OF CONTENTS

VOLUME 2 - APPENDICES

APPENDIX A EXPERIMENTAL DATA FROM PHASE 1A PILOT UNIT OPERATIONS .......... A-1

Table A-1: Total Phosphorus (mg/L) ............................................................................................ A-2 Table A-2: Total Phosphorus (μg/L) ............................................................................................. A-4 Table A-3: Ortho-Phosphorus (mg/L as P) ................................................................................... A-6 Table A-4: Temperature (ºC) ........................................................................................................ A-8 Table A-5: pH ............................................................................................................................. A-10 Table A-6: Dissolved Oxygen (mg/L) ......................................................................................... A-12 Table A-7: Alkalinity (mg CaCO3/L) ............................................................................................ A-14 Table A-8: Conductivity (μS/cm @ 25 ºC) .................................................................................. A-16 Table A-9: cBOD (mg/L) ............................................................................................................. A-18 Table A-10: COD (mg/L) ............................................................................................................ A-19 Table A-11: Ammonia Nitrogen (mg/L) ...................................................................................... A-20 Table A-12: Nitrate Nitrogen (mg/L) ........................................................................................... A-21 Table A-13: Total Coliforms (cfu/100 mL) .................................................................................. A-22 Table A-14: E. coli (cfu/100 mL) ................................................................................................. A-23 Table A-15: Aluminum (μg/L) ..................................................................................................... A-24 Table A-16: Vanadium (μg/L) ..................................................................................................... A-25 Table A-17: Zinc (μg/L)............................................................................................................... A-26 Table A-18: Iron (μg/L) ............................................................................................................... A-27 Table A-19: Manganese (μg/L) .................................................................................................. A-28 Table A-20: Total Chromium (μg/L) ............................................................................................ A-29 Table A-21: Copper (μg/L) ......................................................................................................... A-30 Table A-22: Nickel (μg/L)............................................................................................................ A-31 Table A-23: Lead (μg/L) ............................................................................................................. A-32 Table A-24: Titanium (μg/L) ....................................................................................................... A-33 Table A-25: Cadmium (μg/L) ...................................................................................................... A-34

APPENDIX B EXPERIMENTAL DATA FROM PHASE 1B DEMONSTRATION UNIT TESTING ...................................................................................................... B-1

Table B-1: Total Phosphorus (μg/L) ............................................................................................. B-2 Table B-2: Ortho-Phosphorus (mg/L as P) ................................................................................... B-3 Table B-3 : Temperature (°C) ....................................................................................................... B-4 Table B-4 : pH .............................................................................................................................. B-5 Table B-5 : Dissolved Oxygen (mg/L) .......................................................................................... B-6 Table B-6 : Alkalinity (mg/L as CaCO3) ........................................................................................ B-7 Table B-7 : Conductivity (μS/cm @ 25ºC) .................................................................................... B-8 Table B-8 : Carbonaceous BOD5 (mg/L) ...................................................................................... B-9 Table B-9 : Chemical Oxygen Demand (mg/L) .......................................................................... B-10 Table B-10 : Ammonia Nitrogen (mg/L) ..................................................................................... B-11 Table B-11 : Nitrate Nitrogen (mg/L) .......................................................................................... B-12 Table B-12 : Nitrite Nitrogen (mg/L) ........................................................................................... B-13 Table B-13 : Total Coliforms (cfu/100 mL) ................................................................................. B-14 Table B-14 : E Coli (cfu/100 mL) ................................................................................................ B-15 Table B-15 : Aluminum (µg/L) .................................................................................................... B-16 Table B-16 : Vanadium (µg/L) .................................................................................................... B-17


iv

Table B-17 : Zinc (µg/L).............................................................................................................. B-18 Table B-18 : Iron (µg/L) .............................................................................................................. B-19 Table B-19 : Manganese (µg/L) ................................................................................................. B-20 Table B-20 : Chromium (µg/L) .................................................................................................... B-21 Table B-21 : Copper (µg/L) ........................................................................................................ B-22 Table B-22 : Nickel (µg/L) .......................................................................................................... B-23 Table B-23 : Lead (µg/L) ............................................................................................................ B-24 Table B-24 : Titanium (µg/L) ...................................................................................................... B-25 Table B-25 : Cadmium (µg/L)……………………………………………………………. B-26

APPENDIX C CONSTRUCTED WETLANDS ............................................................................. C-1

C.1 Wetlands ........................................................................................................................... C-2 C.2 Natural Wetlands .............................................................................................................. C-3 C.3 Treatment Wetlands .......................................................................................................... C-4 C.4 Constructed Wetlands ....................................................................................................... C-5 C.5 Stormwater Wetlands ........................................................................................................ C-5 C.6 Constructed Treatment Wetlands ...................................................................................... C-6 C.7 Types of Constructed Wetlands ........................................................................................ C-7 C.8 Free Water Surface Wetlands ........................................................................................... C-8 C.9 Sub-Surface Flow Wetlands .............................................................................................. C-8 C.10 Horizontal Sub-Surface Flow Wetlands ............................................................................. C-9 C.11 Vertical Sub-Surface Flow (VSSF) Wetlands .................................................................. C-10 C.12 CW Vegetation ................................................................................................................. C-11 C.13 Pollutant Removal in CWs ............................................................................................... C-11 C.14 Aerobic Wetlands ............................................................................................................. C-13 C.15 Anaerobic Wetlands ......................................................................................................... C-14 C.16 Advantages and Disadvantages of Constructed Wetlands ............................................. C-15

APPENDIX D ENGINEERED WETLANDS ................................................................................. D-1

D.1 Engineered Wetlands ........................................................................................................ D-2 D.2 EW Systems ...................................................................................................................... D-5 D.3 Engineered Stormwater Wetlands (ESWs) ....................................................................... D-7 D.4 Aerated SSF Wetlands ...................................................................................................... D-8 D.5 Fill & Drain Wetlands ....................................................................................................... D-12 D.6 Anaerobic SSF Wetlands................................................................................................. D-12 D.7 Anaerobic Biochemical Reactors ..................................................................................... D-14 D.8 Wastewaters Treatable in EW Systems .......................................................................... D-16 D.9 Design of EW Systems .................................................................................................... D-19 D.10 Treatability Testing .......................................................................................................... D-21 D.11 The Effect of Temperature on EW Systems .................................................................... D-22 D.12 Sludge formation in EW Systems .................................................................................... D-25

APPENDIX E PHOSPHORUS REMOVAL .................................................................................. E-1

E.1 Lake Simcoe Protection Plan ................................................................................................ E-2 E.2 Phosphorus Basics ............................................................................................................... E-2 E.3 Phosphorus Removal Processes .......................................................................................... E-4

E.3.1 Processes for Phosphorus Removal from Wastewaters .................................. E-4 E.3.2 Phosphorus Removal by Settling ..................................................................... E-4 E.3.3 Phosphorus Removal by Precipitation ............................................................. E-5 E.3.3.1 Phosphorus Removal by Metal Salts ............................................................... E-5 E.3.3.2 Phosphorus Removal Using Alum .................................................................... E-5 E.3.3.3 Phosphorus Removal Using Ferric Chloride .................................................... E-6 E.3.3.4 Phosphorus Removal Using Lime ..................................................................... E-7 E.3.3.5 Phosphorus Removal Using Ferrous and Ferric Sulphates .............................. E-7


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E.3.4 Biological Nutrient Removal ............................................................................... E-7 E.3.5 Combination Processes .................................................................................. E-9 E.3.6 Sorption Processes ............................................................................................ E-9

E.4 Steel Slags .......................................................................................................................... E-11 E.5 The Phosphex Process ........................................................................................................ E-15

E.5.1 The Phosphex™ Patent ..................................................................................... E-15 E.5.2 Development of the Phosphex™ Technology .................................................... E-15 E.5.3 Other Phosphex™ Demonstration Projects ...................................................... E-18

E.6 Phosphorus Removal in Wetlands ...................................................................................... E-19

APPENDIX F REFERENCES ....................................................................................................... F-1

LIST OF OTHER TABLES Table C-1: Effect of Vegetation Root Depth on Ammonia Removal Efficiency in HSSF CWs ... C-9 Table C-2: Comparison of VSSF & HSSF CWs ........................................................................ C-11

Table D-1: BREW Project Pilot Unit Results – Suspended Solids (Septic Overflow Feed) ........ D-8 Table D-2: BREW Project Pilot Unit Results – BOD5 (Septic Overflow Feed) ............................ D-8 Table D-3: BREW Project Pilot Unit Results - NH3-N (Septic Overflow Feed) ........................... D-9 Table D-4: BREW Project Pilot Unit Results – Total Phosphorus (Septic Overflow Feed)......... D-9 Table D-5: BREW Project Pilot Unit Results ............................................................................. D-10 Table D-6: Theoretical Solubilities of Bivalent Cation Sulphides and Hydroxides (mg/L) ........ D-13 Table D-7: Summary of High Temperature Results for Alexandria Treatability Test ................ D-23 Table D-8: EW Rate Constants for High Temperature Runs with Alexandria Sewage ............ D-24 Table D-9: EW Rate for Low Temperature Runs with Alexandria Sewage .............................. D-24 Table D-10: Arrhenius Coefficients for the Alexandria Treatability Test ................................... D-24 Table D-11: Summary of Rate Constant Results for Alexandria Treatability Test .................... D-25

Table E-1: Typical Steel Industry Slag Metal Characterizations (mg/kg) ................................... E-11 Table E-2: Typical Slag Leachate Trace Metal Characterizations (mg/L) ................................. E-12 Table E-3: Isotherm Results For Steel Slags (mg PO4/g substrate) .......................................... E-14 Table E-4: Pilot-Scale BOF Slag EW Results for High Phosphate Wastewaters (SESI,1998) . E-20 LIST OF FIGURES Figure D.1: Heat Balance for Lutsen Sea Villas SSF EW System ............................................ D-23

APPENDIX A EXPERIMENTAL DATA FROM PHASE 1A PILOT UNIT

OPERATIONS

EW-Phosphex Project, Phase 1A, Project 1221 10066 © Stantec, 2010

A-2

Table A-1: Total Phosphorus (mg/L)

Week Date Detection

Outlet of Outlet of Percent Percent

Limit Mixing Aerated Phosphex Removal Removal

(mg/L) Tank Cell Cell Aerated

Cell Phosphex

Cell

Week 1 1-Jun-09 0.02 8.89 3.49 0.17 61% 95.1%

Week 3 17-Jun-09 0.02 8.40 3.13 0.09 63% 97.1%

Week 4 24-Jun-09 0.02 5.49 1.95 <0.02 64% 99.5%

Week 5 2-Jul-09 0.02 5.71 2.51 <0.02 56% 99.6%

** 2-Jul-09 0.02 5.40 2.85 <0.02 47% 99.6%

Week 6 8-Jul-09 0.02 4.57 2.54 <0.02 44% 99.6%

9-Jul-09 0.006 4.762 2.921 <0.006 39% 99.9%

Week 7 15-Jul-09 0.02 3.59 2.25 <0.02 37% 99.6%

Week 8 22-Jul-09 0.02 3.26 2.35 <0.02 28% 99.6%

Week 9 30-Jul-09 0.02 3.59 2.41 <0.02 33% 99.6%

Week 10 5-Aug-09 0.02 3.85 2.45 0.06 36% 97.6%

Week 11 10-Aug-09 0.006 3.361 2.211 <0.006 34% 99.9%

12-Aug-09 0.02 3.75 2.28 <0.02 39% 99.6%

Week 12 19-Aug-09 0.02 4.73 2.12 <0.02 55% 99.5%

Week 13 26-Aug-09 0.02 4.89 2.41 <0.02 51% 99.6%

Week 14 2-Sep-09 0.02 5.14 3.26 <0.02 37% 99.7%

Week 15 9-Sep-09 0.02 4.00 2.77 <0.02 31% 99.6%

Week 16 16-Sep-09 0.02 3.34 3.69 <0.02 -10% 99.7%

Week 17 23-Sep-09 0.02 3.18 2.77 <0.02 13% 99.6%

Week 18 30-Sep-09 0.02 3.59 3.62 <0.02 -1% 99.7%

Week 19 5-Oct-09 0.02 3.51 3.46 <0.02 1% 99.7%

Week 20 14-Oct-09 0.02 4.00 3.03 0.06 24% 98.1%

15-Oct-09 0.003 3.507 2.915 <0.003 17% 99.9%

Week 22 30-Oct-09 0.02 4.65 3.10 <0.02 33% 99.7%

Week 23 4-Nov-09 0.005 5.445 3.625 0.006 33% 99.8%

4-Nov-09 0.02 4.97 3.49 <0.02 30% 99.7%

Week 24 11-Nov-09 0.006 7.320 4.672 0.013 36% 99.7%

11-Nov-09 0.02 7.09 4.08 <0.02 43% 99.8%

Week 25 17-Nov-09 0.005 8.724 4.643 <0.005 47% 99.9%

18-Nov-09 0.02 7.66 4.70 0.08 39% 98.3%

Week 26 * 25-Nov-09 0.02 9.46 5.58 <0.02 41% 99.8%

Week 27 2-Dec-09 0.02 9.46 6.65 0.08 30% 98.7%

Week 28 9-Dec-09 0.02 12.07 7.50 0.15 38% 98.0%

Week 29 16-Dec-09 0.005 11.960 8.121 0.057 32% 99.3%

* 16-Dec-09 0.02 10.27 7.53 0.09 27% 98.7%


A-3

Table A-1 (TP)

(Continued)

Week Date Detection Outlet of Outlet of Outlet of Percent Percent

Limit Mixing Aerated Phosphex Removal Removal

(mg/L) Tank Cell Cell Aerated

Cell Phosphex

Cell

Week 33 14-Jan-10 0.02 8.64 7.60 0.08 12% 99.0%

Week 34 20-Jan-10 0.02 7.34 6.13 0.06 16% 99.0%

Week 35 27-Jan-10 0.008 5.899 5.003 0.012 15% 99.8%

27-Jan-10 0.02 7.50 5.54 0.10 26% 98.2%

Week 36 3-Feb-10 0.008 7.040 6.237 0.011 11% 99.8%

3-Feb-10 0.02 7.18 5.25 0.07 27% 98.7%

Week 38 19-Feb-10 0.008 7.634 5.517 <0.008 28% 99.9%

Average (Weeks 16 - 38)

6.86 4.98 0.04 24% 99.3%

* TP values are slightly lower than corresponding o-PO4 ones (See Table A-3) CAWT samples are un-filtered, UoW samples are filtered

samples analyzed by UoW


A-4

Table A-2: Total Phosphorus (μg/L)

Week Date MDL Outlet of Outlet of Outlet of Outlet of

Mixing Aerated Phosphex Polishing

Tank Cell Cell Cell

Week 1 1-Jun-09 20 8890 3490 170 740

Week 3 17-Jun-09 20 8401 3130 90 270

Week 4 24-Jun-09 20 5490 1950 <20 300

Week 5 2-Jul-09 20 5710 2510 <20 140

* 2-Jul-09 20 5400 2850 <20 130

Week 6 8-Jul-09 20 4570 2540 <20 300

9-Jul-09 5.925 4762.000 2921.000 <5.925 45.600

Week 7 15-Jul-09 20 3590 2250 <20 230

Week 8 22-Jul-09 20 3260 2350 <20 100

Week 9 30-Jul-09 20 3590 2410 <20 620

Week 10 5-Aug-09 20 3850 2450 60 160

Week 11 10-Aug-09 5.925 3361.000 2211.000 <5.925 65.110

12-Aug-09 20 3750 2280 <20 260

Week 12 19-Aug-09 20 4729 2120 <20 567

Week 13 26-Aug-09 20 4892 2413 <20 287

Week 14 2-Sep-09 20 5137 3261 <20 241

Week 15 9-Sep-09 20 3995 2772 <20

Week 16 16-Sep-09 20 3343 3685 <20 4550

Week 17 23-Sep-09 20 3180 2772 <20 3131

Week 18 30-Sep-09 20 3588 3620 <20 3539

Week 19 5-Oct-09 20 3506 3457 <20 3310

Week 20 14-Oct-09 20 3995 3033 59 2544

15-Oct-09 3.281 3507.000 2915.000 <3.281 2872.000

Week 22 30-Oct-09 20 4647 3098 <20 2120

Week 23 4-Nov-09 4.503 5445.000 3625.000 5.544 1333.000

4-Nov-09 20 4974 3490 <20 1353

Week 24 11-Nov-09 5.503 7320.000 4672.000 12.600 757.300

11-Nov-09 20 7094.00 4077 <20 832

Week 25 17-Nov-09 4.948 8724.000 4643.000 <4.948 691.300

18-Nov-09 20 7664 4696 78 701

Week 26 * 25-Nov-09 20 9458 5577 <20 938

Week 27 2-Dec-09 20 9458 6653 85 457

Week 28 9-Dec-09 20 12067 7501 147 511

Week 29 16-Dec-09 4.938 11960.000 8121.000 56.800 91.380

* 16-Dec-09 20 10273 7534 95 380

Week 33 14-Jan-10 20 8643 7599 75 2479

Week 34 20-Jan-10 20 7338 6131 59 261


A-5

Table A-2 TP ppb

(Continued)



Tank Cell Cell Cell

Week 35 27-Jan-10 7.541 5899.000 5003.000 11.900 197.900

27-Jan-10 20 7501 5544 101 264

Week 36 3-Feb-10 7.541 7040.000 6237.000 10.600 212.000

3-Feb-10 20 7175 5251 68 254

Week 38 19-Feb-10 7.541 7634.000 5517.000 <7.541 133.700

*TP (mg/L) values are slightly lower than corresponding o-PO4 (See Table 3) CAWT samples are un-filtered, UoW samples are filtered


** QA/QC check by SGS


A-6

Table A-3: Ortho-Phosphorus (mg/L as P)

Week Date Detection Outlet of Outlet of % Removal

in Outlet of % Removal in

Limit Mixing Aerated Aerated Phosphex Phosphex

Tank Cell Cell Cell Cell

Week 1 3-Jun-09 0.0065 4.34 2.50 42.3% 0.07 97.39%

Week 2 10-Jun-09 0.0065 5.16 2.19 57.6% 0.01 99.70%

Week 3 18-Jun-09 0.033 4.48 1.97 56.0% <0.033 99.16%

Week 3 19-Jun-09 0.0065 5.22 2.33 55.4% 0.01 99.58%

Week 4 24-Jun-09 0.033 5.18 1.97 62.0% <0.033 99.16%

Week 5 2-Jul-09 0.033 4.99 2.32 53.5% <0.033 99.29%

** 2-Jul-09 0.033 4.97 2.49 49.9% <0.033 99.34%

3-Jul-09 0.033 4.99 2.32 53.5% <0.033 99.29%

Week 6 8-Jul-09 0.033 5.11 2.39 53.2% <0.033 99.31%

9-Jul-09 0.005 3.600 0.224 93.8% <0.005 98.88%

10-Jul-09 0.0065 4.27 2.06 51.9% <0.0065 99.84%

Week 7 15-Jul-09 0.033 3.27 2.13 34.9% <0.033 99.22%

21-Jul-09 0.033 2.94 1.84 37.5% <0.033 99.10%

Week 8 22-Jul-09 0.033 3.10 2.16 30.3% <0.033 99.24%

24-Jul-09 0.033 3.33 2.25 32.4% <0.033 99.27%

Week 9 30-Jul-09 0.033 2.85 1.84 35.4% <0.033 99.10%

30-Jul-09 0.033 3.03 2.12 29.8% <0.033 99.22%

Week 10 5-Aug-09 0.033 2.82 1.74 38.4% <0.033 99.05%

7-Aug-09 0.033 3.15 1.93 38.7% <0.033 99.14%

Week 11 10-Aug-09 0.005 2.992 1.789 40.2% 0.009 99.50%

12-Aug-09 0.033 3.19 1.90 40.3% <0.033 99.13%

14-Aug-09 0.033 6.40 2.89 54.8% <0.033 99.43%

Week 12 19-Aug-09 0.033 4.08 2.20 46.0% <0.033 99.25%

21-Aug-09 0.033 4.01 2.24 44.3% <0.033 99.26%

Week 13 26-Aug-09 0.033 4.96 2.76 44.4% <0.033 99.40%

31-Aug-09 0.033 3.90 2.08 46.7% <0.033 99.21%

Week 14 2-Sep-09 0.033 3.97 2.40 39.4% <0.033 99.31%

3-Sep-09 0.033 4.18 2.35 43.8% <0.033 99.30%

Week 15 9-Sep-09 0.033 3.26 2.43 25.5% <0.033 99.32%

10-Sep-09 0.033 2.85 2.23 21.8% <0.033 99.26%

Week 16 16-Sep-09 0.033 2.23 2.16 3.2% <0.033 99.24%

Week 20 15-Oct-09 0.005 2.830 2.330 17.7% <0.005 99.89%

Week 22 30-Oct-09 0.0065 4.11 2.79 32.1% <0.0065 99.88%

Week 23 4-Nov-09 0.0065 4.67 3.26 30.1% 0.01 99.80%

Week 24 11-Nov-09 0.0065 6.04 3.82 36.8% 0.04 98.97%

Week 25 17-Nov-09 0.005 6.370 3.634 43.0% <0.005 99.93%

18-Nov-09 0.0065 6.82 4.41 35.4% 0.05 98.89%

Week 26 * 25-Nov-09 0.0065 9.20 6.33 31.2% 0.08 98.71%


A-7

Table A-3 o-PO4

(Continued)

Week Date Detection Outlet of Outlet of % Removal

in Outlet of % Removal in

Limit Mixing Aerated Aerated Phosphex Phosphex


Week 27 2-Dec-09 0.0065 9.27 6.85 26.1% 0.06 99.14%

Week 28 9-Dec-09 0.0065 7.61 5.55 27.1% <0.0065 99.94%

Week 29 16-Dec-09 0.005 5.249 4.486 14.5% 0.005 99.89%

16-Dec-09 0.005 10.016 6.447 35.6% 0.065 98.99%

16-Dec-09 0.0065 12.27 7.18 41.5% 0.12 98.36%

Week 33 14-Jan-10 0.0065 8.06 7.37 8.5% 0.04 99.42%

Week 34 20-Jan-10 0.005 7.624 5.335 30.0% 0.009 99.83%

20-Jan-10 0.0065 6.07 6.00 1.1% 0.07 98.91%

Week 35 27-Jan-10 0.0065 5.45 4.50 17.4% 0.07 98.48%

Week 36 3-Feb-10 0.0065 5.64 4.83 14.5% 0.02 99.59%

Week 38 19-Feb-10 0.005 5.412 3.992 26.2% 0.007 99.82%

Average Weeks 16 - 38 6.94 5.07 26.2% 0.037 97.27%

* Ortho phosphate values are slightly higher than corresponding TP ones (see Table A.1).

Analyses with an MDL of 0.033 mg/L were taken on the CAWT Ion Chromatograph

Analyses with an MDL of 0.065 mg/L were taken on a Hach using Method 8048

All samples were filtered

** QA/QC check by SGS



A-8

Table A-4: Temperature (ºC)

Week Date Outlet of Outlet of Outlet of Outlet of


Tank Cell Cell Cell

Week 1 1-Jun-09 23.5 24.1 23.7 25.2

Week 3 17-Jun-09 23.7 24.7 24.3 23.9

Week 4 24-Jun-09 24.6 25.5 24.5 24.6

Week 5 2-Jul-09 21.9 22.3 22.1 21.7

Week 6 8-Jul-09 21.7 22.6 22.2 22.0

Week 7 15-Jul-09 23.1 24.2 23.4 22.3

Week 8 22-Jul-09 23.8 24.6 24.1 24.0

Week 9 30-Jul-09 22.8 23.6 23.1 22.8

Week 10 5-Aug-09 24.3 25.1 24.3 23.8

Week 11 12-Aug-09 25.0 25.6 25.0 25.5

Week 12 19-Aug-09 25.1 26.4 25.6 24.8

Week 13 26-Aug-09 24.4 24.8 24.3 24.1

Week 14 2-Sep-09 21.6 21.3 21.0 20.9

Week 15 9-Sep-09 24.1 24.5 23.9

Week 16 16-Sep-09 21.9 22.6 21.8 22.1

Week 17 23-Sep-09 22.7 22.5 22.0 22.6

Week 18 30-Sep-09 19.2 19.1 18.7 18.6

2-Oct-09 18.9 16.7

Week 19 5-Oct-09 20.3 19.4

6-Oct-09 19.9

Week 19 7-Oct-09 18.6 18.6 18.2 17.6

8-Oct-09 20.2 19.4

7-Oct-09 18.6 18.6 18.2 17.6

9-Oct-09 20.3 20.1

Week 20 13-Oct-09 18.7 18.6

14-Oct-09 16.4 16.9 16.3 15.6

15-Oct-09 15.7 16.9

16-Oct-09 17.0 16.1

Week 21 19-Oct-09 18.7 16.8

20-Oct-09 23.0 21.2

21-Oct-09 20.2 20.7

22-Oct-09 16.0 16.7 15.9 16.2

23-Oct-09 13.7 14.4 13.6 13.1

Week 22 26-Oct-09 14.4 14.1


A-9

Table A-4 Temperature

(Continued)

Week

Date

Outlet of Mixing Tank

Outlet of Aerated

Cell

Outlet of Phosphex

Cell

Outlet of Polishing

Cell

Week 22 27-Oct-09 19.5 19.3

28-Oct-09 16.8 1.1

29-Oct-09 17.2 16.1

Week 23 2-Nov-09 17.1 16.0

3-Nov-09 18.2 17.5

6-Nov-09 13.6 12.9

Week 24 9-Nov-09 18.1 16.5

Week 24 10-Nov-09 17.4 16.7

13-Nov-09 16.1 15.5

Week 25 16-Nov-09 18.0 17.1

19-Nov-09 14.6 13.3

20-Nov-09 14.6 14.3

Week 26 26-Nov-09 15.0 14.4

27-Nov-09 15.0 15.2

Week 27 30-Nov-09 15.5 14.3

2-Dec-09 12.8 13.3 12.9 12.5

3-Dec-09 14.4 14.7

Week 28 7-Dec-09 13.4 12.5

9-Dec-09 14.1 14.6 14.6 14.7

Week 29 14-Dec-09 16.8 16.7

15-Dec-09 17.1 16.6

16-Dec-09 15.9 16.0 15.7 15.5

17-Dec-09 17.5

Week 33 14-Jan-10 17.3 16.3 15.4 18.9

Week 34 20-Jan-10 17.3 17.9 17.3 16.8

Week 35 27-Jan-10 17.2 17.7 17.0 17.1

Week 36 3-Feb-10 15.8 16.6 15.3 16.2

Average Weeks 16-26 17.1 17.4 15.4 14.7


A-10

Table A-5: pH

Week Date Outlet of Outlet of Outlet of Open Tank

Mixing Aerated Phosphex

Tank Cell Cell

Week 1 1-Jun-09 8.54 8.54 12.19 11.67

Week 3 17-Jun-09 8.30 8.62 12.35 11.90

22-Jun-09 8.09 8.62 12.34 12.07

Week 4 24-Jun-09 8.15 8.62 12.32 12.01

26-Jun-09 7.96 8.61 12.28 12.01

29-Jun-09 7.98 8.66 12.36 12.14

Week 5 2-Jul-09 8.02 8.57 12.35 12.17

2-Jul-09 8.17 8.46 12.30 12.00

Week 6 8-Jul-09 8.09 8.60 12.35 12.07

9-Jul-09 8.38 8.62 12.19 12.05

Week 7 15-Jul-09 8.17 8.53 12.30 11.85

Week 8 22-Jul-09 7.94 8.31 11.80 11.49

Week 9 30-Jul-09 7.70 8.24 11.70 11.48

Week 10 5-Aug-09 7.92 8.48 11.95 11.76

Week 11 12-Aug-09 7.68 8.41 11.78 11.45

Week 12 19-Aug-09 7.49 8.49 11.65 10.22

Week 13 26-Aug-09 7.52 8.45 11.72 11.11

Week 14 2-Sep-09 7.53 8.29 11.87 11.40

Week 15 9-Sep-09 7.68 8.41 11.64

Week 16* 16-Sep-09 7.82 8.33 11.69 6.80

Week 17 23-Sep-09 8.00 8.58 11.88 7.25

24-Sep-09 11.50

25-Sep-09 11.37 7.07

28-Sep-09 11.71 7.26

29-Sep-09 11.44 6.84

Week 18 30-Sep-09 7.49 8.09 11.03 6.95

1-Oct-09 11.35 7.14

2-Oct-09 11.25 7.14

Week 19 5-Oct-09 11.65 7.11

6-Oct-09 11.86 7.28

7-Oct-09 7.74 8.40 11.59 7.18

8-Oct-09 11.92 7.34

9-Oct-09 11.80 7.04

Week 20 13-Oct-09 11.32 7.29

14-Oct-09 7.86 8.50 11.80 7.28

15-Oct-09 11.77 7.33

15-Oct-09 8.01 8.62 11.98 7.51

16-Oct-09 11.42 7.38


A-11

Table A-5 pH

Week Date Outlet of Outlet of Outlet of Open Tank

Mixing Aerated Phosphe

x

Tank Cell Cell

Week 21 19-Oct-09 11.78 7.41

20-Oct-09 11.89 7.44

21-Oct-09 11.58 7.44

22-Oct-09 7.71 8.41 11.50 7.00

23-Oct-09 7.65 8.41 11.60 7.34

Week 22 26-Oct-09 11.61 7.27

27-Oct-09 11.63 7.24

28-Oct-09 11.29 7.33

29-Oct-09 11.64 7.45

Week 23 2-Nov-09 11.64 7.33

3-Nov-09 11.21 7.31

6-Nov-09 11.17 7.18

Week 24 9-Nov-09 11.14 7.07

10-Nov-09 11.52 7.43

13-Nov-09 11.54 7.30

Week 25 16-Nov-09 11.55 7.42

17-Nov-09 7.73 8.39 11.74 7.53

19-Nov-09 11.46 6.87

20-Nov-09 11.40 6.94

Week 26 23-Nov-09 11.23 6.82

24-Nov-09 11.66 7.13

26-Nov-09 11.50 6.91

27-Nov-09 11.27 6.88

Week 27 30-Nov-09 11.62 7.16

2-Dec-09 7.42 7.85 11.15 7.24

3-Dec-09 11.36 7.39

Week 28 7-Dec-09 11.31 7.50

9-Dec-09 7.91 8.11 11.41 7.90

Week 29 14-Dec-09 11.52 7.72

15-Dec-09 11.44 7.55

16-Dec-09 7.63 7.99 11.35 7.46

17-Dec-09 11.47

Week 33 14-Jan-10 7.72 7.59 11.60 7.91

Week 34 20-Jan-10 7.94 7.75 11.11 7.34

Week 35 27-Jan-10 7.66 7.58 10.96 6.97

Week 36 3-Feb-10 7.82 7.70 11.12 7.14

Week 38 9-Feb-10 7.99 7.57 11.46 7.47

Average Weeks 16-38 7.78 8.11 11.70 7.39

UoW Values *Open Tank moved


A-12

Table A-6: Dissolved Oxygen (mg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 10.7 8.1 2.0 3.5

Week 3 17-Jun-09 7.3 7.4 2.1 4.3

Week 4 24-Jun-09 5.4 5.7 1.4 1.6

Week 5 2-Jul-09 6.2 7.0 1.4 3.2

5* 2-Jul-09 5.3 7.0 6.6 4.4

Week 6 8-Jul-09 6.5 7.0 1.2 1.8

Week 7 15-Jul-09 6.7 6.9 1.6 2.1

Week 8 22-Jul-09 7.0 7.0 1.4 1.7

Week 9 30-Jul-09 6.6 7.0 1.7 2.2

Week 10 5-Aug-09 6.5 7.2 1.7 2.5

Week 11 12-Aug-09 3.0 6.9 1.8 3.4

Week 12 19-Aug-09 1.0 7.4 1.8 1.8

Week 13 26-Aug-09 1.1 7.2 2.2 2.2

Week 14 2-Sep-09 4.0 8.7 1.7 2.9

Week 15 9-Sep-09 5.5 7.7 2.2

Week 16 16-Sep-09 5.9 8.0 2.9 3.5

Week 17 23-Sep-09 5.1 7.7 2.1 3.5

Week 18 30-Sep-09 4.8 8.9 2.7 3.9

1-Oct-09 6.8 3.6

2-Oct-09 3.1 6.1

Week 19 5-Oct-09 4.4 3.8

6-Oct-09 2.7

Week 19 7-Oct-09 4.9 8.7 2.0 3.7

8-Oct-09 3.2 3.7

9-Oct-09 2.5 4.2

Week 20 13-Oct-09 2.9 5.6

14-Oct-09 5.7 8.7 2.1 4.1

15-Oct-09 2.2 4.0

16-Oct-09 2.7 5.2

Week 21 19-Oct-09 2.3 5.0

20-Oct-09 2.7 4.6

21-Oct-09 2.5 8.1

22-Oct-09 6.7 9.7 2.9 3.9

23-Oct-09 9.9 9.9 2.1 8.1

Week 22 26-Oct-09 3.5 5.4

27-Oct-09 2.7 5.0


A-13

Table A-6 DO

(continued)

Week

Date


Outlet of Aerated

Cell

Outlet of Phosphex

Cell

Outlet of Polishing

Cell

Week 22 28-Oct-09 3.0 4.2

29-Oct-09 2.5 4.4

Week 23 2-Nov-09 4.8 4.9

3-Nov-09 3.0 4.7

6-Nov-09 4.9 4.7

Week 24 9-Nov-09 6.2 7.7

10-Nov-09 5.7 4.9

13-Nov-09 4.2 5.8

Week 25 16-Nov-09 3.2 5.0

19-Nov-09 3.9 5.9

20-Nov-09 4.0 5.6

Week 26 23-Nov-09 4.9 4.8

24-Nov-09 4.6 4.6

26-Nov-09 4.3 4.7

27-Nov-09 6.0 8.0

Week 27 30-Nov-09 4.3 7.9

2-Dec-09 5.7 9.7 4.9 7.9

3-Dec-09 4.9 7.3

Week 28 7-Dec-09 3.8 7.1

9-Dec-09 3.1 10.8 5.6 7.1

Week 29 14-Dec-09 5.5 8.3

15-Dec-09 5.5 7.2

16-Dec-09 1.9 9.4 4.3 6.9

Week 33 14-Jan-10 3.4 3.7 3.0 6.4

Week 34 20-Jan-10 1.5 7.2 3.8 3.5

Week 35 27-Jan-10 3.6 6.9 4.8 4.4

Week 36 3-Feb-10 2.7 7.6 5.3 4.5

Average Weeks 16 - 36 4.8 8.4 3.8 5.4

* QA/QC check by SGS


A-14

Table A-7: Alkalinity (mg CaCO3/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 243 175 1560 342

Week 3 17-Jun-09 248 220 1292 952

Week 4 24-Jun-09 256 220 1030 582

Week 5 2-Jul-09 252 224 1052 556

Week 5* 2-Jul-09 254 241 995 621

Week 6 8-Jul-09 236 232 964 528

Week 7 15-Jul-09 224 220 880 324

Week 8 22-Jul-09 212 228 744 356

Week 9 30-Jul-09 224 220 680 400

Week 10 5-Aug-09 232 212 592 352

Week 11 12-Aug-09 276 236 524 292

Week 12 19-Aug-09 284 236 480 216

Week 13 26-Aug-09 256 222 478 164

Week 14 2-Sep-09 268 226 422 146

Week 15 9-Sep-09 222 224 420

Week 16 16-Sep-09 240 240 340 688

Week 17 23-Sep-09 256 248 424 472

Week 18 30-Sep-09 266 252 386 258

1-Oct-09 374 227

2-Oct-09 378 206

Week 19 5-Oct-09 426 200

7-Oct-09 266 254 446 196

Week 20 13-Oct-09 456 194

14-Oct-09 284 270 410 182

16-Oct-09 410 194

Week 21 19-Oct-09 442 208

21-Oct-09 435 195

22-Oct-09 268 268 426 198

Week 22 29-Oct-09 398 174

Week 23 2-Nov-09 354 152

Week 24 13-Nov-09 278 230

Week 26 30-Nov-09 280 348

Week 27 2-Dec-09 398 225 265 335

3-Dec-09 264 252


A-15

Table A-7 Alkalinity

(continued)

Week

Date


Outlet of Aerated

Cell

Outlet of Phosphex

Cell

Outlet of Polishing

Cell

Week 28 7-Dec-09 286 292

9-Dec-09 450 225 228 238

Week 29 14-Dec-09 244 200

15-Dec-09 254 184

16-Dec-09 488 205 280 200

Week 33 14-Jan-10

Week 34 20-Jan-10 560 170 203 175

Week 35 27-Jan-10 620 168 210 122

Week 36 3-Feb-10 625 194 200 130

Average Weeks 16-36 393 227 337 248

* QA/QC check by SGS MDL = 10 mg CaCO3/L


A-16

Table A-8: Conductivity (μS/cm @ 25 ºC)



Tank Cell Cell Cell

Week 1 1-Jun-09 936 787 6710 1780 Week 3 17-Jun-09 977 920 5710 2117 Week 4 24-Jun-09 957 921 5050 2556 Week 5* 2-Jul-09 906 890 4917 3080

2-Jul-09 893 876 4470 2770

Week 6 8-Jul-09 895 877 4726 2588 Week 7 15-Jul-09 823 825 3751 1735 Week 8 22-Jul-09 802 803 3534 1762 Week 9 30-Jul-09 823 800 3410 1856 Week 10 5-Aug-09 865 812 2924 1856 Week 11 12-Aug-09 958 893 2800 1505 Week 12 19-Aug-09 1025 928 2480 741 Week 13 26-Aug-09 1078 978 2693 1055 Week 14** 2-Sep-09 1092 1020 2664 1358 Week 15 9-Sep-09 1031 1031 2691

Week 16 16-Sep-09 1100 1069 2296 1757 Week 18 30-Sep-09 1077 1047 2296 954 1-Oct-09 2236 928 2-Oct-09 2264 865 Week 19 5-Oct-09 2476 894 6-Oct-09 2395 872 Week 19 7-Oct-09 1091 1063 2582 874 Week 19 7-Oct-09 1091 1063 2582 874 8-Oct-09 2481 838 9-Oct-09 2519 873 Week 20 13-Oct-09 2509 894

14-Oct-09 1089 1069 2353 843 15-Oct-09 2392 865 16-Oct-09 2368 878 Week 21 19-Oct-09 2489 906 20-Oct-09 2465 848 21-Oct-09 2380 893


A-17

Table A-8 Conductivity

(continued)

Week

Date


Outlet of Aerated

Cell

Outlet of Phosphex

Cell

Outlet of Polishing

Cell

Week 21 22-Oct-09 1031 1018 2312 856 23-Oct-09 80 876 1916 707 Week 22 26-Oct-09 2377 878 27-Oct-09 2507 903 28-Oct-09 2354 901 29-Oct-09 2379 858 Week 23 2-Nov-09 2154 849 3-Nov-09 2371 857 6-Nov-09 1928 880 Week 24 9-Nov-09 2047 995 10-Nov-09 1875 1007 13-Nov-09 1836 982 Week 25 16-Nov-09 1872 866 19-Nov-09 1924 1297 Week 25 20-Nov-09 2114 1329 Week 26 23-Nov-09 1702 1145 24-Nov-09 1783 1082 26-Nov-09 1968 1233 27-Nov-09 1112 1000 1668 1134 Week 27 30-Nov-09 1791 1127 2-Dec-09 1560 1021 3-Dec-09 1283 1102 1742 1096 Week 28 7-Dec-09 1895 1138 9-Dec-09 1584 1005 Week 29 14-Dec-09 1388 1161 1870 1053 15-Dec-09 1765 1031 16-Dec-09 1642 977 Week 33 14-Jan-10 1406 1138 1653 1112 Week 34 20-Jan-10 1663 1318 1655 1096 Week 35 27-Jan-10 1642 1318 1669 978 Week 36 3-Feb-10 1788 1465 1873 1078 Average Weeks 16-36 1306 1126 2091 988

MDL = 5 μS/cm * Sample sent to SGS for QA/QC


A-18

Table A-9: cBOD (mg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 48 42 <1 18 Week 3 17-Jun-09 37 39 <1 8 Week 4 24-Jun-09 11 5 <1 5 Week 5 2-Jul-09 12 8 <1 2

* 2-Jul-09 <4 <4 <4 <4 Week 6 8-Jul-09 8 4 <1 <1 Week 7 15-Jul-09 6 8 <1 <1 Week 8 22-Jul-09 5 7 <1 <1 Week 9 30-Jul-09 8 9 <1 <1

Week 10 5-Aug-09 6 11 <1 <1 Week 11 12-Aug-09 9 11 <1 <1 Week 12 19-Aug-09 17 8 <1 <1 Week 13 26-Aug-09 10 4 <1 <1 Week 14 2-Sep-09 9 7 <1 3 Week 15 9-Sep-09 4 7 <1 11

Week 23 4-Nov-09 8 <1 <1 Week 24 11-Nov-09 10 2 <1 4 Week 25 18-Nov-09 12 4 <1 6 Week 26 25-Nov-09 10 6 <1 5 Week 27 2-Dec-09 11 7 <1 7 Week 28 9-Dec-09 27 7 <1 6 Week 29 16-Dec-09 24 3 <1 5 Week 29 16-Dec-09 24 3 <1 5 Week 34 20-Jan-10 46 10 <1 6 Week 36 3-Feb-10 57 10 <1 <1 Average Weeks 16-36 26 6 <1 5

MDL = 1 mg/L at CAWT, 4 mg/ at SGS * Sample sent to SGS for QA/QC


A-19

Table A-10: COD (mg/L)

Week Date Outlet of Outlet of Outlet of % Removal Outlet of

Mixing Aerated Phosphex in Phosphex Polishing


Week 1 1-Jun-09 81 115 48 58.7% 183 Week 3 17-Jun-09 32 25 16 38.7% 111 Week 4 24-Jun-09 56 27 15 43.0% 91 Week 5 2-Jul-09 33 27 9 65.7% 50

Week 5* 2-Jul-09 30 32 9 71.9% 46 Week 6 8-Jul-09 29 27 15 42.7% 51 Week 7 15-Jul-09 24 23 7 68.9% 47 Week 8 22-Jul-09 27 29 8 71.8% 42 Week 9 30-Jul-09 5 9 <3 83.8% 27

Week 10 5-Aug-09 11 12 1 89.1% 15 Week 11 12-Aug-09 29 22 9 60.2% 32 Week 12 19-Aug-09 32 31 4 87.9% 63 Week 13 26-Aug-09 27 27 11 60.0% 40 Week 14 2-Sep-09 32 42 12 71.6% 34 Week 15 9-Sep-09 25 36 14 59.4%

Week 16 16-Sep-09 23 80 13 83.9% 55 Week 17 23-Sep-09 26 36 13 64.3% 36 Week 18 30-Sep-09 25 58 10 82.6% 43 Week 22 30-Oct-09 31 26 12 55.1% 23 Week 23 4-Nov-09 34 32 14 56.9% 31 Week 24 11-Nov-09 38 32 15 53.3% 19 Week 25 18-Nov-09 37 30 14 51.2% 20 Week 25 18-Nov-09 37 30 14 51.2% 20 Week 26 25-Nov-09 42 30 9 69.0% 18 Week 27 2-Dec-09 51 30 10 67.1% 7

Week 28 9-Dec-09 78 27 16 39.5% 14 Week 29 16-Dec-09 79 21 <3 93.0% <3 Week 33 14-Jan-10 113 32 9 73.3% 31 Week 34 20-Jan-10 105 36 13 64.3% 15 Week 35 27-Jan-10 127 44 27 38.6% 22 Week 36 3-Feb-10 113 28 15 45.8% 15 Average Weeks 16-36 61 36 13 65.0 % 23

MDL = 3 mg/L * Sample sent to SGS for QA/QC


A-20

Table A-11: Ammonia Nitrogen (mg/L)

Week Date Outlet of Outlet of %

Removal Outlet of Outlet of

Mixing Aerated in Aerated Phosphex Polishing


Week 1 1-Jun-09 0.06 0.05 16.67% 0.60 5.90 Week 3 17-Jun-09 0.16 <0.02 93.75% 0.41 6.40 Week 4 24-Jun-09 0.40 <0.02 97.50% 0.29 6.50 Week 5 2-Jul-09 0.15 <0.02 93.33% 0.22 3.60

Week 5* 2-Jul-09 0.50 <0.1 90.00% 0.20 3.70 Week 6 8-Jul-09 0.37 <0.02 97.30% 0.20 4.50 Week 7 15-Jul-09 0.37 <0.02 97.30% 0.25 3.60 Week 8 22-Jul-09 0.05 0.03 40.00% 0.17 3.70 Week 9 30-Jul-09 0.77 0.06 92.21% 0.19 4.50

Week 10 5-Aug-09 0.65 <0.02 98.46% 0.15 2.90

Week 11 12-Aug-09 1.23 <0.02 99.19% 0.07 2.60 Week 12 19-Aug-09 4.30 <0.02 99.77% 0.23 6.30 Week 14 2-Sep-09 4.20 0.08 98.10% 0.12 2.80 Week 15 9-Sep-09 0.11 0.13 -18.18% 0.22 Average Weeks 1 -15 0.89 0.03 96.62 % 0.22 Week 16 16-Sep-09 0.40 <0.02 97.50% 0.08 2.60

Week 22 30-Oct-09 <0.02 0.14 2.10 Week 23 4-Nov-09 4.30 0.01 99.77% 0.07 1.80 Week 24 11-Nov-09 10.80 0.04 99.63% 0.11 1.48 Week 25 18-Nov-09 15.60 0.07 99.55% 0.06 1.48 Week 26 25-Nov-09 17.50 0.25 98.57% 0.09 2.10 Week 27 2-Dec-09 30.90 0.38 98.77% 0.06 0.95 Week 28 9-Dec-09 40.00 0.03 99.93% 0.07 1.52 Week 29 16-Dec-09 40.30 0.06 99.85% 0.09 0.98 Week 33 14-Jan-10 46.00 0.40 99.13% 3.60 3.70 Week 34 20-Jan-10 14.20 0.80 94.37% 0.40 1.40 Week 35 27-Jan-10 53.20 6.10 88.53% 0.57 0.60 Week 36 3-Feb-10 57.60 0.20 99.65% 0.23 1.14 Average Weeks 16 - 36 27.6 0.64 97.67% 0.43 1.68

MDL = 0.02 mg/L, * Sample sent to SGS for QA/QC


A-21

Table A-12: Nitrate Nitrogen (mg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 1.66 2.29 1.62 0.53 Week 3 17-Jun-09 5.42 3.44 1.40 <0.05 Week 4 24-Jun-09 7.48 5.13 2.85 <0.05 Week 5 2-Jul-09 10.80 7.80 4.61 <0.05

Week 5* 2-Jul-09 9.31 7.26 4.38 0.06 Week 6 8-Jul-09 11.18 8.61 4.78 <0.05 Week 7 15-Jul-09 9.49 7.52 6.88 <0.05 Week 8 22-Jul-09 8.02 6.92 6.52 0.08 Week 9 29-Jul-09 7.14 6.24 5.79 0.28 Week 9 30-Jul-09 7.30 6.56 5.90 0.18

Week 10 5-Aug-09 7.02 6.35 5.28 0.63 7-Aug-09 7.92 7.12 6.37 0.71

Week 11 12-Aug-09 6.44 6.76 6.36 0.24 Week 12 19-Aug-09 3.82 5.14 5.04 1.74 Week 13 26-Aug-09 3.47 7.52 5.33 2.35 Week 14 2-Sep-09 5.33 9.97 7.51 2.86 Week 15 9-Sep-09 7.33 8.33 9.17 Average Weeks 1 -15 6.27 5.94 4.73 0.54 Week 16 16-Sep-09 5.38 4.06 6.04 Week 22 30-Oct-09 5.04 5.49 3.51 <0.05 Week 23 4-Nov-09 5.21 6.88 4.69 0.28 Week 24 11-Nov-09 5.57 11.40 7.79 0.84 Week 25 18-Nov-09 3.95 13.75 10.55 2.18 Week 26 25-Nov-09 2.60 25.94 18.35 3.69 Week 27 2-Dec-09 1.30 33.04 25.65 12.41 Week 28 9-Dec-09 1.29 39.12 31.25 10.59

Week 29 16-Dec-09 0.08 17.21 10.94 Week 33 14-Jan-10 <0.05 42.91 28.44 11.35 Week 34 20-Jan-10 <0.05 52.48 41.60 19.32 Week 35 27-Jan-10 <0.05 92.50 78.28 41.34 Week 36 3-Feb-10 <0.05 60.20 56.73 32.86 Average Weeks 16 - 36 2.34 32.31 25.39 12.15

MDL = 0.05 mg/L, * Sample sent to SGS for QA/QC


A-22

Table A-13: Total Coliforms (cfu/100 mL)



Tank Cell Cell Cell

Week 1 1-Jun-09 4250 <100 <60 <30 Week 3 17-Jun-09 330 345 <30 <6 Week 4 24-Jun-09 3270 215 <3 <3 Week 5 2-Jul-09 3970 275 <3 <3 Week 6 8-Jul-09 1940 1085 <3 <3 Week 7 15-Jul-09 12120 2935 <3 <3 Week 8 22-Jul-09 760 >6060 <3 <3 Week 9 30-Jul-09 >24240 >4848 <3 <3

Week 10 5-Aug-09 2120 1875 <3 <3 Week 11 12-Aug-09 6700 55 <3 <3 Week 12 19-Aug-09 2800 8 <3 <3 Week 13 26-Aug-09 1040 204 <3 <3 Week 14 2-Sep-09 1040 118 <3 <3 Week 15 9-Sep-09 1440 26 <3 Week 16 16-Sep-09 440 26 <3 16 Week 22 30-Oct-09 165 <3 <3 <3 Week 23 4-Nov-09 66 <3 <3 114 Week 24 11-Nov-09 228 <3 <3 <3 Week 25 18-Nov-09 1230 5 <3 46 Week 26 25-Nov-09 1320 19 <3 46 Week 27 2-Dec-09 1060 5 <3 22 Week 28 9-Dec-09 >24240 5 <3 5 Week 29 16-Dec-09 >24240 5 <3 <3 Week 33 14-Jan-10 1610 90 <3 Week 34 20-Jan-10 1770 33 <3 <3 Week 35 27-Jan-10 3390 49 <3 25 Week 36 3-Feb-10 19400 132 <3 <3

MDL = 3 cfu/100 mL


A-23

Table A-14: E. coli (cfu/100 mL)



Tank Cell Cell Cell

Week 1 1-Jun-09 <1500 <100 <60 <30 Week 3 17-Jun-09 300 165 <10 <6 Week 4 24-Jun-09 140 <15 <3 <3 Week 5 2-Jul-09 295 8 <3 <3

* 2-Jul-09 190 8 <2 <2 Week 6 8-Jul-09 <15 13 <3 <3 Week 7 15-Jul-09 5870 390 <3 <3 Week 8 22-Jul-09 160 28 <3 <3 Week 9 30-Jul-09 13700 1020 <3 <3

Week 10 5-Aug-09 <60 <15 <3 <3 Week 11 12-Aug-09 1570 20 <3 <3 Week 12 19-Aug-09 2090 8 <3 <3 Week 13 26-Aug-09 380 32 <3 <3 Week 14 2-Sep-09 220 22 <3 <3 Week 15 9-Sep-09 260 26 <3 Week 16 16-Sep-09 60 10 <3 <3 Week 22 30-Oct-09 25 <3 <3 <3 Week 23 4-Nov-09 32 <3 <3 90 Week 24 11-Nov-09 <3 <3 <3 <3 Week 25 18-Nov-09 110 3 <3 3 Week 26 25-Nov-09 250 <3 <3 39 Week 27 2-Dec-09 30 <3 <3 3 Week 28 9-Dec-09 >24240 <3 <3 <3 Week 29 16-Dec-09 4180 3 <3 <3 Week 33 14-Jan-10 130 5 <3 Week 34 20-Jan-10 980 30 <3 <3 Week 35 27-Jan-10 1660 19 <3 <3 Week 36 3-Feb-10 12300 69 <3 <3

MDL = 3 cfu/100 mL


A-24

Table A-15: Aluminum (μg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 3 36 56 463 644 Week 3 17-Jun-09 3 66 66 504 344 Week 4 24-Jun-09 3 30 61 530 1027 Week 5 2-Jul-09 3 34 28 594 1039

* 2-Jul-09 3 20 20 670 1020 Week 6 8-Jul-09 3 <3 21 456 Week 6 9-Jul-09 0.029 4.413 20.970 821.1 1334.0 Week 7 15-Jul-09 3 13 12 814 996 Week 8 22-Jul-09 3 13 15 1081 566 Week 9 30-Jul-09 3 21 30 1006 1291

Week 10 5-Aug-09 3 63 403 967 1303 10-Aug-09 0.449 <0.449 21.31 1183.00 1516.00

Week 11 12-Aug-09 3 66 58 1010 1196 Week 12 19-Aug-09 3 77 67 842 1104 Week 13 26-Aug-09 3 64 74 937 1035

31-Aug-09 3 121 73 956 963 Week 14 2-Sep-09 3 55 80 880 929 Week 15 9-Sep-09 3 61 76 993

Week 20 15-Oct-09 0.055 2.025 5.162 955.20 23.38 Week 23 4-Nov-09 3 9 9 723 24

4-Nov-09 0.453 10.610 3.310 817.600 27.820 Week 24 11-Nov-09 3 9 13 675 15

11-Nov-09 0.000 <0.000 2.216 637.20 10.67 Week 25 17-Nov-09 0.082 <0.082 0.125 707.500 5.987

18-Nov-09 3 10 9 591 10 Week 26 25-Nov-09 3 6 6 737 9 Week 27 2-Dec-09 3 4 5 583 16 Week 28 9-Dec-09 3 6 4 230 28 Week 29 16-Dec-09 3 15 4 473

16-Dec-09 0.08 6.079 <0.080 424.60 39.95 Week 33 14-Jan-10 3 16 4 534 20 Week 34 20-Jan-10 3 32 6 402 21 Week 35 27-Jan-10 3 28 5 221 33

27-Jan-10 0.419 7.771 0.816 186.10 22.22 Week 36 3-Feb-10 0.419 5.634 <0.419 430.50 13.32

3-Feb-10 3 21 6 404 33 Week 38 19-Feb-10 0.41 5.760 <0.419 217.00 14.66 Average Weeks 16-38 1.84 10.22 4.327** 523 14.33

* QA/QC check by SGS Samples analyzed by UoW PWQO = 75 μg/L in pH 6.5 to 9.0 range, none thereafter ** Probably higher than actual average of ~<1 μg/L


A-25

Table A-16: Vanadium (μg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 3 49 40 149 38 Week 3 17-Jun-09 3 20 8 <3 <3 Week 4 24-Jun-09 3 <3 <3 <3 <3 Week 5 2-Jul-09 3 <3 <3 <3 <3

* 2-Jul-09 3 1 2 1 1 Week 6 8-Jul-09 3 14 5 <3 <3

9-Jul-09 0.029 0.623 1.834 1.932 1.800

Week 7 15-Jul-09 3 <3 <3 <3 3 Week 8 22-Jul-09 3 <3 <3 <3 3 Week 9 30-Jul-09 3 3 <3 4 6

Week 10 5-Aug-09 3 <3 <3 5 4

10-Aug-09 0.449 <0.035 2.168 4.991 5.160

Week 11 12-Aug-09 3 <3 <3 6 4 Week 12 19-Aug-09 3 <3 <3 11 7 Week 13 26-Aug-09 3 <3 <3 11 4

31-Aug-09 3 <3 60 20 6

Week 14 2-Sep-09 3 <3 <3 20 5 Week 15 9-Sep-09 3 <3 <3 <3

Week 20 15-Oct-09 0.015 1.139 1.283 12.900 2.108 Week 23 4-Nov-09 3 <3 <3 23 8

4-Nov-09 0.015 0.614 1.033 15.800 6.962

Week 24 11-Nov-09 3 <3 <3 32 7

11-Nov-09 0.007 0.564 1.468 36.570 8.454

Week 25 17-Nov-09 0.007 0.695 1.285 32.390 9.887

18-Nov-09 3 <3 <3 34 6

Week 26 25-Nov-09 3 <3 <3 29 5 Week 27 2-Dec-09 3 5 3 39 20 Week 28 9-Dec-09 3 <3 <3 36 12 Week 28 9-Dec-09 3 <3 <3 36 12 Week 29 16-Dec-09 3 <3 <3 41

16-Dec-09 0.009 0.529 0.730 48.470 21.930

Week 33 14-Jan-10 3 <3 <3 <3 34 Week 34 20-Jan-10 3 <3 <3 <3 40 Week 35 27-Jan-10 3 <3 <3 33 21

27-Jan-10 0.008 0.532 1.041 44.210 26.300

Week 36 3-Feb-10 0.008 0.473 0.722 47.120 23.570

3-Feb-10 3 <3 <3 36 18

Week 38 19-Feb-10 0.008 0.556 0.732 47.53 26.37 Average Weeks 16-38 1.741 1.374 1.445 32.81 16.54

PWQO = 6 μg/L

Samples analyzed by UoW

* sample sent to SGS for QA/QC


A-26

Table A-17: Zinc (μg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 5 14 9 <5 14 Week 3 17-Jun-09 5 57 13 <5 <5 Week 4 24-Jun-09 5 8 5 <5 9 Week 5 2-Jul-09 5 <5 <5 <5 <5

* 2-Jul-09 5 3 3 3 7 Week 6 8-Jul-09 5 5 7 <5 <5

9-Jul-09 0.057 2.907 3.402 6.636 4.658

Week 7 15-Jul-09 5 <5 5 <5 <5 Week 8 22-Jul-09 5 <5 <5 <5 <5 Week 9 30-Jul-09 5 <5 <5 <5 5

Week 10 5-Aug-09 5 11 117 13 22 10-Aug-09 0.067 <0.067 4.530 4.671 12.180

Week 11 12-Aug-09 5 15 8 15 12 Week 12 19-Aug-09 5 10 8 5 13 Week 13 26-Aug-09 5 8 <5 8 10

31-Aug-09 5 12 8 6 19 Week 14 2-Sep-09 5 10 11 <5 20 Week 15 9-Sep-09 5 11 5 7

Week 20 15-Oct-09 0.083 16.410 5.559 2.069 6.465 Week 23 4-Nov-09 5 7 <5 <5 <5

4-Nov-09 0.025 8.567 4.606 1.598 5.109 Week 24 11-Nov-09 5 9 <5 16 7

11-Nov-09 0.086 12.100 8.322 23.650 10.880 Week 25 17-Nov-09 0.086 35.330 3.173 1.268 23.300

18-Nov-09 5 13 5 <5 19 Week 26 25-Nov-09 5 5 9 <5 9 Week 27 2-Dec-09 5 6 <5 5 12 Week 28 9-Dec-09 5 6 <5 <5 12 Week 29 16-Dec-09 5 8 <5 <5

16-Dec-09 0.072 22.440 4.435 3.465 14.200 Week 33 14-Jan-10 5 <5 5 <5 7 Week 34 20-Jan-10 5 10 <5 <5 8 Week 35 27-Jan-10 5 22 6 <5 5

27-Jan-10 1.559 5.931 5.792 4.367 5.574 Week 36 3-Feb-10 5 23 <5 <5 8

3-Feb-10 0.071 4.394 3.672 1.388 7.22 Week 38 19-Feb-10 0.071 15.27 6.969 3.922 7.505 Average Weeks 16-38 3.003 12.126 4.446 4.481 8.958

PWQO = 20 μg/L, * Sample sent to SGS for QA/QC



A-27

Table A-18: Iron (μg/L)



Tank Cell Cell Cell

Week 10 5-Aug-09 231 448 86 126 Week 11 12-Aug-09 38 36 21 52 Week 12 19-Aug-09 22 27 18 165 Week 13 26-Aug-09 54 44 43 102

31-Aug-09 74 40 18 112 Week 14 2-Sep-09 34 64 63 79 Week 15 9-Sep-09 21 25 19

Week 23 4-Nov-09 12 8 6 52 Week 24 11-Nov-09 23 7 <5 30 Week 25 18-Nov-09 26 8 7 18 Week 26 25-Nov-09 45 10 5 28 Week 27 2-Dec-09 99 32 23 33 Week 28 9-Dec-09 107 17 11 14 Week 29 16-Dec-09 159 6 202 59 Week 33 14-Jan-10 54 41 34 59 Week 34 20-Jan-10 78 19 14 28 Week 35 27-Jan-10 68 14 9 17 Week 36 3-Feb-10 55 13 8 18 Average Weeks 16-38 66 16 29 32

MDL = 5 μg/L, PWQO = 300 μg/L


A-28

Table A-19: Manganese (μg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 7 13 <7 <7 46 Week 3 17-Jun-09 7 128 <7 <7 14 Week 4 24-Jun-09 7 <7 <7 <7 <7 Week 5 2-Jul-09 7 <7 <7 <7 <7

* 2-Jul-09 7 2 0 1 4 Week 6 8-Jul-09 7 10 <7 <7 <7

9-Jul-09 0.057 3.695 0.558 2.568 7.453 Week 7 15-Jul-09 7 <7 <7 <7 <7 Week 8 22-Jul-09 7 <7 <7 <7 <7 Week 9 30-Jul-09 7 <7 <7 <7 9

Week 10 5-Aug-09 7 39 54 12 10-Aug-09 0.067 <0.067 0.331 1.933 5.864

Week 11 12-Aug-09 7 <7 <7 <7 <7 Week 12 19-Aug-09 7 <7 <7 <7 16 Week 13 26-Aug-09 7 39 <7 <7 28

31-ug-09 7 48 <7 <7 36 Week 14 2-Sep-09 7 42 <7 <7 25 Week 15 9-Sep-09 7.000 18 <7 <7

Week 20 15-Oct-09 0.019 9.722 0.466 0.886 84.860 Week 23 4-Nov-09 7 12 <7 <7 71

4-Nov-09 0.008 15.910 0.394 0.770 67.920 Week 24 11-Nov-09 7 35 <7 <7 78

11-Nov-09 0.000 40.750 1.138 1.622 90.350

17-Nov-09 0.012 47.390 1.016 1.255 100.600

Week 25 18-Nov-09 7 37 <7 <7 146 Week 26 25-Nov-09 7 58 <7 <7 224 Week 27 2-Dec-09 7 74 <7 <7 58 Week 28 9-Dec-09 7 68 <7 <7 89 Week 29 16-Dec-09 7 87 <7 <7

16-Dec-09 0.012 101.300 0.649 0.753 8.064 Week 33 14-Jan-10 7 60 17 <7 118 Week 34 20-Jan-10 7 52 <7 <7 60 Week 35 27-Jan-10 7 54 <7 <7 47

27-Jan-10 0.012 84.240 1.017 0.319 54.090 Week 36 3-Feb-10 7 52 <7 <7 53

3-Feb-10 0.012 65.320 0.469 0.915 49.040 Week 38 19-Feb-10 0.012 1.156 0.486 5.026 1.221

Average Weeks 16-38 4.057 50.098 3.044 2.634 74.117 Samples analyzed by UoW *QA/QC check by SGS No PWQO


A-29

Table A-20: Total Chromium (μg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 5 <5 <5 <5 <5 Week 3 17-Jun-09 5 137 29 8 7 Week 4 24-Jun-09 5 12 6 <5 30 Week 5 2-Jul-09 5 <5 <5 <5 <5

* 2-Jul-09 5 <0.5 <0.5 <0.5 <0.5 Week 6 8-Jul-09 5 16 8 <5 <5

9-Jul-09 0.009 0.041 0.058 2.125 0.458 Week 7 15-Jul-09 5 <5 <5 <5 <5 Week 8 22-Jul-09 5 <5 <5 5 <5 Week 9 30-Jul-09 5 <5 <5 <5 13

Week 10 5-Aug-09 5 <5 <5 <5 <5 10-Aug-09 0.031 <0.031 <0.031 3.850 <0.031

Week 11 12-Aug-09 5 <5 <5 <5 <5 Week 12 19-Aug-09 5 <5 <5 <5 <5 Week 13 26-Aug-09 5 <5 <5 <5 <5

31-Aug-09 5 <5 <5 <5 <5 Week 14 2-Sep-09 5 <5 <5 <5 <5 Week 15 9-Sep-09 5 <5 <5 <5

Week 16 16-Sep-09 5 Week 20 15-Oct-09 0.019 0.134 0.105 3.943 2.095 week 23 4-Nov-09 0.011 0.390 0.049 3.589 0.129

4-Nov-09 5 11 12 14 13 Week 24 11-Nov-09 0.000 0.233 0.253 4.377 0.370

11-Nov-09 5 11 12 15 10 Week 25 17-Nov-09 0.011 0.182 0.260 4.709 0.565

18-Nov-09 5 12 10 13 10 Week 26 25-Nov-09 5 10 10 13 9 Week 27 2-Dec-09 5 6 <5 <5 <5 Week 28 9-Dec-09 5 <5 <5 <5 <5 Week 29 16-Dec-09 0.012 0.382 0.097 4.205 1.319

16-Dec-09 5 23 12 22 Week 33 14-Jan-10 5 11 13 16 13 Week 34 20-Jan-10 5 14 12 13 12 Week 35 27-Jan-10 0.015 0.308 0.224 4.028 1.064

27-Jan-10 5 14 14 15 14 Week 36 3-Feb-10 0.011 0.249 0.161 4.321 1.141

3-Feb-10 5 13 13 16 13 Week 39 19-Feb-10 0.011 1.156 0.486 5.026 1.221

Average Weeks 16-39 6.852 6.039 9.215 5.953

PWQO 8.9 µg/L Samples analyzed by UoW


A-30

Table A-21: Copper (μg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 3 98 42 20 16 Week 3 17-Jun-09 3 95 43 <3 5 Week 4 24-Jun-09 3 35 24 6 11 Week 5 2-Jul-09 3 26 19 <3 5

5* 2-Jul-09 3 19 22 4 4 Week 6 8-Jul-09 3 61 41 20 6

9-Jul-09 0.021 20.950 20.230 6.656 6.447 Week 7 15-Jul-09 3 138 123 49 66 Week 8 22-Jul-09 3 67 86 23 40 Week 9 30-Jul-09 3 33 23 17 14

Week 10 5-Aug-09 3 29 79 75 165 Week 11 10-Aug-09 0.029 18.360 23.930 12.000 10.210

12-Aug-09 3 71 44 85 24 Week 12 19-Aug-09 3 46 20 11 15 Week 13 26-Aug-09 3 <3 12 8 8

31-Aug-09 3 <3 13 6 10 Week 14 2-Sep-09 3 8 13 <3 12 Week 15 9-Sep-09 3 <3 14 4

Week 16 16-Sep-09 3 Week 20 15-Oct-09 0.043 25.040 14.860 6.415 4.041 Week 23 4-Nov-09 0.043 9.604 12.340 6.266 4.413

4-Nov-09 3 11 15 9 5 Week 24 11-Nov-09 0.000 14.690 17.820 14.860 11.330

11-Nov-09 3 12 17 13 6 Week 25 17-Nov-09 0.02 30.640 19.810 10.600 102.400

18-Nov-09 3 27 14 11 8 Week 26 25-Nov-09 3 7 13 9 5 Week 27 2-Dec-09 3 14 17 14 9 Week 28 9-Dec-09 3 10 12 6 9 Week 29 16-Dec-09 0.02 8.198 22.480 24.930 16.810

16-Dec-09 3 4 10 9 Week 33 14-Jan-10 3 <3 14 10 <3 Week 34 20-Jan-10 3 10 12 8 5 Week 35 27-Jan-10 0.027 4.282 15.800 7.935 6.751

27-Jan-10 3 15 11 6 5 Week 36 3-Feb-10 0.021 4.345 11.360 8.325 7.741

3-Feb-10 3 15 12 7 7 Week 38 19-Feb-10 0.021 8.499 12.230 6.794 8.283 Average Weeks 20 -38

12.161 14.443 9.489 12.294

PWQO = 6 μg/L, * Sample sent to SGS for QA/QC



A-31

Table A-22: Nickel (μg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 13 <13 <13 <13 <13

Week 3 17-Jun-09 13 <13 <13 <13 <13

Week 4 24-Jun-09 13 <13 <13 <13 <13

Week 5 2-Jul-09 13 <13 <13 <13 <13

* 2-Jul-09 13 2.6 2.6 0.8 2.3

Week 6 8-Jul-09 13 <13 <13 <13 <13

9-Jul-09 0.015 2.087 1.874 0.356 1.250

Week 7 15-Jul-09 13 <13 <13 <13 <13

Week 8 22-Jul-09 13 <13 <13 <13 <13

Week 9 30-Jul-09 13 <13 <13 <13 <13

Week 10 5-Aug-09 13 <13 <13 <13 <13

Week 11 10-Aug-09 0.042 1.920 1.938 0.428 1.255

12-Aug-09 13 <13 <13 <13 <13

Week 12 19-Aug-09 13 <13 <13 <13 <13

Week 13 26-Aug-09 13 <13 <13 <13 <13

31-Aug-09 13 <13 <13 <13 <13

Week 14 2-Sep-09 13 <13 <13 <13 <13

Week 15 9-Sep-09 13 <13 <13 <13 <13

Week 16 16-Sep-09 13 <13 <13 <13 <13

Week 20 15-Oct-09 0.018 2.741 2.087 0.781 1.581

Week 23 4-Nov-09 0.088 3.846 1.895 0.714 1.183

4-Nov-09 13 <13 <13 <13 <13

Week 24 11-Nov-09 0.000 2.672 2.785 1.464 1.315

11-Nov-09 13 <13 <13 <13 <13

Week 25 17-Nov-09 0.021 2.486 2.506 1.663 1.735

Week 25 18-Nov-09 13 <13 <13 <13 <13

Week 26 25-Nov-09 13 <13 <13 <13 <13

Week 27 2-Dec-09 13 <13 <13 <13 <13

Week 28 9-Dec-09 13 <13 <13 <13 <13

Week 29 16-Dec-09 0.021 3.909 2.323 1.316 1.380

16-Dec-09 13 <13 <13 <13 <13

Week 33 14-Jan-10 13 <13 <13 <13 <13

Week 34 20-Jan-10 13 <13 <13 <13 <13

Week 35 27-Jan-10 0.053 3.305 2.561 1.759 1.374

27-Jan-10 13 <13 <13 <13 <13

Week 36 3-Feb-10 0.053 2.514 2.007 0.974 1.351

Week 37 3-Feb-10 13 <13 <13 <13 <13

Week 38 19-Feb-10 0.053 3.820 8.445 1.037 1.313

Average Weeks 16-38

5.165 5.135 4.385 4.462

PWQO = 25 μg/L, * Sample sent to SGS for QA/QC Samples analyzed by UoW


A-32

Table A-23: Lead (μg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 11 <11 <11 <11 <11

Week 3 17-Jun-09 11 291 38 <11 15

Week 4 24-Jun-09 11 <11 14 11 24

Week 5 2-Jul-09 11 <11 <11 <11 <11

* 2-Jul-09 11 <11 <11 <11 <11

Week 6 8-Jul-09 11 71 <11 <11 <11

9-Jul-09 0.002 0.048 0.048 0.329 0.152

Week 7 15-Jul-09 11 <11 <11 <11 <11

Week 8 22-Jul-09 11 <11 <11 <11 <11

Week 9 30-Jul-09 11 <11 11 18 <11

Week 10 5-Aug-09 11 <11 208 <11 73

Week 11 10-Aug-09 0.005 <0.005 0.137 0.138 0.104

12-Aug-09 11 <11 77 67 35

Week 12 19-Aug-09 11 44 <11 <11 <11

Week 13 26-Aug-09 11 13 <11 20 <11

31-Aug-09 11 <11 178 16 <11

Week 14 2-Sep-09 11 <11 <11 <11 <11

Week 15 9-Sep-09 11 <11 <11 <11

Week 20 15-Oct-09 0.006 0.714 0.066 0.077 0.102

Week 23 4-Nov-09 0.002 0.026 0.021 0.045 0.062

4-Nov-09 11 <11 <11 <11 <11

Week 24 11-Nov-09 0.000 0.448 0.334 0.580 0.466

11-Nov-09 11 <11 <11 <11 <11

Week 25 17-Nov-09 0.002 57.920 0.225 0.148 0.502

18-Nov-09 11 <11 <11 <11 <11

Week 26 25-Nov-09 11 <11 <11 11 <11

Week 27 2-Dec-09 11 <11 <11 <11 <11

Week 28 9-Dec-09 11 <11 <11 <11 <11

Week 29 16-Dec-09 0.002 0.473 0.900 0.224 1.104

16-Dec-09 11 <11 <11 19 <11

Week 33 14-Jan-10 11 <11 <11 <11 <11

Week 34 20-Jan-10 11 <11 <11 <11 <11

Week 35 27-Jan-10 0.003 2.271 0.196 0.169 0.144

27-Jan-10 11 <11 <11 13 <11

Week 36 3-Feb-10 0.002 0.644 0.447 0.364 1.088

3-Feb-10 11 <11 <11 <11 <11

Week 38 19-Feb-10 0.002 0.487 0.293 0.108 0.061

Average Weeks 16-38

6.499 3.315 4.395 3.370

PWQO = 5 μg/L, * Sample sent to SGS for QA/QC Samples analyzed by UoW


A-33

Table A-24: Titanium (μg/L)



Tank Cell Cell Cell

Week 1 1-Jun-09 2 16 <2 <2 2

Week 3 17-Jun-09 2 27 76 <2 <2

Week 4 24-Jun-09 2 32 41 <2 82

Week 5 2-Jul-09 2 7 6 6 7

* 2-Jul-09 2 <1 <1 <1 <1

Week 6 8-Jul-09 2 65 33 <2 <2

9-Jul-09 0.064 0.477 0.225 <0.064 0.127

Week 7 15-Jul-09 2 <2 <2 <2 <2

Week 8 22-Jul-09 2 <2 <2 <2 <2

Week 9 30-Jul-09 2 10 7 <2 20

Week 10 5-Aug-09 2 <2 11 10 5

Week 11 10-Aug-09 0.181 <0.181 0.324 <0.181 0.296

12-Aug-09 2 <2 <2 <2 <2

Week 12 19-Aug-09 2 <2 <2 <2 <2

Week 13 26-Aug-09 2 <2 <2 <2 <2

31-Aug-09 2 <2 <2 <2 <2

Week 14 2-Sep-09 2 <2 <2 <2 <2

Week 15 9-Sep-09 2 21 <2 <2

Week 20 15-Oct-09 0.125 0.519 0.464 <0.125 1.644

Week 23 4-Nov-09 0.107 1.198 0.510 0.012 0.653

4-Nov-09 2 <2 <2 <2 <2

Week 24 11-Nov-09 0.000 1.313 1.246 0.335 0.329

11-Nov-09 2 <2 <2 <2 <2

Week 25 17-Nov-09 0.127 1.466 0.803 <0.127 <0.127

18-Nov-09 2 <2 <2 <2 <2

Week 26 25-Nov-09 2 2 2 2 <2

Week 27 2-Dec-09 2 16 12 15 11

Week 28 9-Dec-09 2 9 5 8 5

Week 29 16-Dec-09 0.099 2.674 1.811 <0.099 0.227

16-Dec-09 2 39 2 98 18

Week 33 14-Jan-10 2 22 19 24 19

Week 34 20-Jan-10 2 21 9 12 12

Week 35 27-Jan-10 0.09 1.833 1.547 0.706 0.971

27-Jan-10 2 7 4 8 9

Week 36 3-Feb-10 0.059 15.940 14.220 0.634 1.033

3-Feb-10 2 12 6 7 8

Week 38 19-Feb-10 0.059 16.530 12.390 0.621 0.742

Average Weeks 16-36

9.056 4.997 9.423 4.822 No PWQO, * Sample sent to SGS for QA/QC



A-34

Table A-25: Cadmium (μg/L)


Mixing Aerated Phosphex Polishing Tank Cell Cell Cell

Week 1 1-Jun-09 3 132.2 77.4 408.1 225.4 Week 3 17-Jun-09 3 8.8 <3 <3 <3 Week 4 24-Jun-09 3 <3 <3 <3 <3 Week 5 2-Jul-09 3 <3 <3 <3 <3

* 2-Jul-09 3 <3 <3 <3 <3 Week 6 8-Jul-09 3 <3 <3 <3 <3

9-Jul-09 0.001 0.013 0.012 0.007 0.011 Week 7 15-Jul-09 3 <3 <3 <3 <3 Week 8 22-Jul-09 3 <3 <3 <3 <3 Week 9 30-Jul-09 3 <3 <3 <3 <3

Week 10 5-Aug-09 3 <3 <3 <3 <3 Week 11 10-Aug-09 0.018 <0.018 <0.018 <0.018 <0.018

12-Aug-09 3 <3 <3 <3 <3 Week 12 19-Aug-09 3 <3 <3 <3 <3 Week 13 26-Aug-09 3 <3 <3 <3 <3

31-Aug-09 3 <3 <3 <3 <3 Week 14 2-Sep-09 3 <3 <3 <3 <3 Week 15 9-Sep-09 3 <3 <3 <3

Week 20 15-Oct-09 0.010 <0.010 0.022 <0.010 <0.010 Week 23 4-Nov-09 0.010 0.007 0.018 0.004 0.012

4-Nov-09 3 <3 <3 <3 <3 Week 24 11-Nov-09 0.000 0.060 0.041 0.192 0.042

11-Nov-09 3 <3 <3 <3 <3 Week 25 17-Nov-09 0.001 0.053 0.015 0.002 0.024

18-Nov-09 3 <3 <3 <3 <3 Week 26 25-Nov-09 3 <3 <3 <3 <3 Week 27 2-Dec-09 3 <3 <3 <3 <3 Week 28 9-Dec-09 3 <3 <3 <3 <3 Week 29 16-Dec-09 0.001 0.059 0.013 0.026 0.026

16-Dec-09 3 <3 <3 <3 Week 33 14-Jan-10 3 <3 <3 <3 <3 Week 34 20-Jan-10 3 <3 <3 <3 <3 Week 35 27-Jan-10 0.002 0.014 0.026 0.013 0.013

27-Jan-10 3 <3 <3 <3 <3 Week 36 3-Feb-10 0.002 0.018 0.032 0.014 0.026

3-Feb-10 3 <3 <3 <3 <3 Week 38 19-Feb-10 0.002 0.027 0.026 0.012 0.022

Average Weeks 16-36

0.881 0.879 0.883 0.843 PWQO = 0.2 μg/L, * Sample sent to SGS for QA/QC Samples analyzed by UoW

APPENDIX B EXPERIMENTAL DATA FROM PHASE 1B

DEMONSTRATION UNIT TESTING

EW-Phosphex Project, Phase 1B Treatability Testing, 1221 10067 © Stantec, 2010

B-2

Table B-1: Total Phosphorus (μg/L)

Date Outlet

of Outlet of Outlet of % Removal Outlet of % Removal %

Removal

Holding HSSF CW Aerated in Aerated Phosphex in Phosphex in EW

Tank Cell VSSF EW VSSF EW Cell Cell System

Cell Cell

Week 1 27-Jan-

10

9.28 5.46 2.63 51.78% 0.23 91.36% 95.84%

Week 2 3-Feb-10 12.72 6.52 2.80 57.00% 0.06 97.79% 99.05%

Week 15 5-May-10 7.13 8.01 4.31 46.18% 1.72 60.14% 78.55%

Week 16 12-May-

10 8.44 6.19 4.16 32.71% 0.89 78.67% 85.65%

Week 17 19-May-10 7.67 6.63 3.68 44.58% 0.28 92.41% 95.79%

Week 18 27-May-10 6.94 6.58 2.97 54.87% 0.24 91.96% 96.37%

Week 19 2-Jun-10 8.08 5.91 2.00 66.17% 0.14 93.24% 97.71%

Week 20 8-Jun-10 8.64 6.82 2.32 66.03% 0.32 86.20% 95.31%

Week 21 16-Jun-

10 10.15 7.99 2.87 64.08% 0.15 94.77% 98.12%

Week 22 23-Jun-

10 12.46 7.10 3.77 46.94% 0.85 77.50% 88.06%

Week 23 29-Jun-

10 6.85 7.54 3.08 59.14% 0.59 80.77% 92.14%

Week 24 6-Jul-10 8.12 9.52 1.97 79.28% 0.19 90.41% 98.01%

Week 25 14-Jul-10 4.96 7.34 2.04 72.22% 0.79 61.28% 89.24%

Week 26 20-Jul-10 6.33 8.19 2.90 64.54% 0.18 93.93% 97.85%

Week 27 28-Jul-10

6.49 8.90 2.80 68.50% 0.33 88.14% 96.26%

Week 28 4-Aug-10

4.96 4.86 3.47 28.52% 0.26 92.58% 94.70%

Week 29 10-Aug-10

5.51 5.48 3.77 31.25% 0.45 88.05% 91.79%

Week 30 18-Aug-10

5.94 7.83 3.75 52.08% 0.79 78.87% 89.88%

Week 31 31-Aug-10

3.82 4.34 4.45 -2.63% n/a n/a n/a

Week 32 8-Sep-10

4.14 3.20 4.19 -31.12% 0.75 82.10% 76.53%


7.04 6.80 3.25 52.21% 0.49 84.78% 92.72

MDL <0.02 mg TP/L by Hach method 8190, all samples unfiltered Total phosphorus (mg/L) values are slightly lower than corresponding ortho-phosphate as P values (mg/L)

EW-Phosphex Project, Phase 1B Treatability Testing, 1221 10067 B-3 © Stantec, 2010

Table B-2: Ortho-Phosphorus (mg/L as P)

Date Outlet

of Outlet

of Outlet of % Removal Outlet of % Removal % Removal

Holding HSSF CW Aerated in Aerated Phosphex in Phosphex in EW

Tank Cell VSSF EW Cell Cell Cell System

Cell

Week 1 27-Jan-10 5.40 3.57 0.95 73.29% <0.033 98.27% 99.54%

27-Jan-10 6.471 4.262 2.420 43.21% 0.005 99.79% 99.88%

Week 2 3-Feb-10 2.80 3.36 1.89 43.66% <0.033 99.13% 99.51%

3-Feb-10 7.155 4.893 2.309 52.82% 0.005 99.78% 99.90%

Week 11 6-Apr-10 3.910 4.786 3.282 31.43% 0.061 98.14% 98.73%

13-Apr-10 4.358 5.049 4.078 19.23% 0.012 99.70% 99.76%

Week 14 30-Apr-10 5.280 7.472 5.020 32.82% 0.010 99.81% 99.87%

Week 15 5-May-10 3.35 5.04 4.41 12.53% 0.12 97.25% 97.59%

Week 16 12-May-10 4.66 4.77 3.32 30.29% <0.033 99.50% 99.65%

Week 17 19-May-10 6.33 6.24 2.69 56.90% <0.033 99.39% 99.74%

21-May-10 5.417 6.170 4.665 24.39% 0.005 99.89% 99.92%

Week 18 27-May-10 5.16 5.41 2.58 52.35% <0.033 99.36% 99.69%

Week 19 2-Jun-10 6.55 5.24 0.81 84.51% <0.033 97.97% 99.69%

Week 20 8-Jun-10 8.52 6.83 2.88 57.87% <0.033 99.43% 99.76%

Week 21 16-Jun-10 8.24 7.36 4.39 40.42% <0.033 99.62% 99.78%

18-Jun-10 7.545 6.444 2.340 63.69% 0.005 99.79% 99.92%

Week 22 23-Jun-10 7.76 5.33 3.21 39.76% <0.033 99.49% 99.69%

Week 23 29-Jun-10 7.50 8.82 4.79 45.62% <0.033 99.66% 99.81%

Week 24 6-Jul-10 7.64 9.49 1.99 79.03% <0.033 99.17% 99.83%

Week 25 14-Jul-10 5.48 8.86 3.23 63.52% <0.033 99.49% 99.81%

Week 26 20-Jul-10 5.47 7.85 2.66 66.12% <0.033 99.38% 99.79%

Week 27 28-Jul-10 5.48 7.22 2.50 65.35% <0.033 99.34% 99.77%

Week 28 4-Aug-10 4.62 5.09 3.43 32.70% <0.033 99.52% 99.68%

Week 29 10-Aug-10 5.51 5.55 4.21 24.19% <0.033 99.61% 99.70%

Week 30 18-Aug-10 4.82 7.50 3.37 55.10% 0.10 97.04% 98.67%

Average (Weeks 15 - 30) 5.89 6.50 3.33 46.56% 0.03 99.17% 99.56%

All samples were filtered to 45 µm and phosphate values are expressed as phosphorus

Ortho-phosphate as P values (mg/L) are slightly higher than corresponding Total Phosphorus (mg/L)

CAWT samples measured by Ion Chromatograph, MDL = 0.033 mg/L as P

UofW samples measured by Hach Method 8048, MDL = 0.005 mg/L as P

>MDL averaged as 1/2 MDL (Clark, 1998)


Table B-3 : Temperature (°C)

Date Outlet of Outlet of Outlet of Outlet of

Holding HSSF CW Aerated Phosphex

Tank Cell VSSF EW Cell

Cell

Week 1 27-Jan-10 4.5 4.8 5.3 4.0

Week 2 3-Feb-10 7.1 7.0 5.6 6.6

Week 15 5-May-10 17.2 16.8 16.2 16.0

Week 16 12-May-10 14.9 16.0 10.9 14.6

Week 17 19-May-10 15.3 15.6 16.6 13.7

Week 18 27-May-10 17.2 19.0 21.0 16.9

Week 19 2-Jun-10 18.1 20.0 21.2 17.8

Week 20 8-Jun-10 21.6 22.2 22.1 21.9

Week 21 16-Jun-10 17.6 19.1 19.2 17.4

Week 22 23-Jun-10 21.9 21.5 21.5 21.9

Week 23 29-Jun-10 19.8 21.4 21.0 21.4

Week 24 6-Jul-10 21.3 22.8 22.8 22.6

Week 25 14-Jul-10 23.0 24.1 23.1 21.5

Week 26 20-Jul-10 17.5 18.4 23.6 21.8

Week 27 28-Jul-10

22.8 23.0 22.9 22.8

Week 28 4-Aug-10

23.5 23.5 23.5 23.4

Week 29 10-Aug-10

24.4 23.2 25.9 23.8

Week 30 18-Aug-10

21.3 21.9 22.5 21.8

Week 31 31-Aug-10

23.4 23.3 23.3 23.3


20.0 20.7 21.0 20.1

Note: temperatures reflect sample temperature shortly after sampling but may not accurately reflect temperature within the Demonstration Unit.


Table B-4 : pH




Cell

Week 1 27-Jan-10 7.53 7.79 7.48 11.35

Week 2 3-Feb-10 7.98 8.11 8.10 11.83

Week 15 5-May-10 7.23 7.63 7.80 11.52

Week 16 12-May-10 7.19 7.63 8.06 11.29

Week 17 19-May-10 7.02 7.66 8.17 11.60

Week 18 27-May-10 7.22 7.69 8.13 11.53

Week 19 2-Jun-10 6.83 7.64 8.29 11.89

Week 20 8-Jun-10 7.04 7.55 8.26 11.29

Week 21 16-Jun-10 7.15 7.33 8.29 11.85

Week 22 23-Jun-10 6.98 7.33 7.76 11.52

Week 23 29-Jun-10 7.70 7.71 8.22 11.39

Week 24 6-Jul-10 7.01 7.22 8.14 11.56

Week 25 14-Jul-10 7.27 7.61 8.07 11.96

Week 26 20-Jul-10 7.50 7.55 8.45 11.86

Week 27 28-Jul-10

7.60 7.93 8.58 11.81

Week 28 4-Aug-10

7.62 7.95 8.25 11.84

Week 29 10-Aug-10

7.46 7.78 8.40 12.20

Week 30 18-Aug-10

7.68 7.84 8.21 11.88

Week 31 31-Aug-10

7.73 7.87 8.10 11.69


7.31 7.64 8.19 11.69


Table B-5 : Dissolved Oxygen (mg/L)




Cell

Week 1 27-Jan-10 1.39 1.37 11.64 2.97

Week 2 3-Feb-10 0.26 0.20 11.42 3.83

Week 15 5-May-10 3.49 0.70 8.74 6.02

Week 16 12-May-10 0.85 2.43 10.89 3.44

Week 17 19-May-10 0.20 2.16 12.28 4.00

Week 18 27-May-10 1.80 1.63 9.01 2.63

Week 19 2-Jun-10 0.13 1.02 8.78 2.74

Week 20 8-Jun-10 0.22 2.44 9.23 6.78

Week 21 16-Jun-10 0.42 2.02 8.97 2.62

Week 22 23-Jun-10 0.14 1.42 7.19 4.59

Week 23 29-Jun-10 4.85 3.14 8.51 4.95

Week 24 6-Jul-10 0.35 2.30 8.41 4.33

Week 25 14-Jul-10 2.35 0.18 6.50 3.04

Week 26 20-Jul-10 0.19 0.26 8.37 2.36

Week 27 28-Jul-10

1.50 4.30 8.40 3.74

Week 28 4-Aug-10

2.54 4.48 8.15 3.84

Week 29 10-Aug-10

0.85 1.32 8.18 3.09

Week 30 18-Aug-10

0.51 2.32 8.92 3.16

Week 31 31-Aug-10

3.70 2.53 8.42 6.10


1.42 2.04 8.76 3.97


Table B-6 : Alkalinity (mg/L as CaCO3)




Cell

Week 1 27-Jan-10 6353 455 195 2298

Week 2 3-Feb-10 763 538 225 2360

Week 15 5-May-10 728 248 250 403

Week 16 12-May-10 594 564 240 343

Week 17 19-May-10 650 450 275 768

Week 18 27-May-10 536 638 320 682

Week 19 2-Jun-10 638 605 253 1535

Week 20 8-Jun-10 613 688 295 443

Week 21 16-Jun-10 578 660 323 1675

Week 22 23-Jun-10 533 550 288 713

Week 23 29-Jun-10 493 570 350 255

Week 24 6-Jul-10 470 605 300 1238

Week 25 14-Jul-10 368 470 275 825

Week 26 20-Jul-10 420 470 248 1530

Week 27 28-Jul-10

343 415 203 800

Week 28 4-Aug-10

343 363 225 1525

Week 29 10-Aug-10

355 370 213 1265

Week 30 18-Aug-10

303 323 185 858

Week 31 31-Aug-10

310 340 241 823


486 490 264 922

MDL = 10 mg/L


Table B-7 : Conductivity (μS/cm @ 25ºC)




Cell

Week 1 27-Jan-10 2118 1441 1349 8160

Week 2 3-Feb-10 2048 1504 1192 7500

Week 15 5-May-10 1818 1903 1706 2262

Week 16 12-May-10 1728 1706 1574 2258

Week 17 19-May-10 1947 1840 1699 4350

Week 18 27-May-10 1841 2000 1716 4720

Week 19 2-Jun-10 1830 1971 1686 7040

Week 20 8-Jun-10 1948 2021 1630 2489

Week 21 16-Jun-10 1705 1845 1540 7520

Week 22 23-Jun-10 1821 1852 1630 4020

Week 23 29-Jun-10 1579 1671 1510 1929

Week 24 6-Jul-10 1569 1774 1544 6280

Week 25 14-Jul-10 1360 1541 1440 7890

Week 26 20-Jul-10 1004 1468 1303 7480

Week 27 28-Jul-10

1256 1330 1231 4160

Week 28 4-Aug-10

1207 1337 1197 7360

Week 29 10-Aug-10

1222 1225 1128 6050

Week 30 18-Aug-10

1121 1187 1113 4500

Week 31 31-Aug-10

1101 1168 1093 2500


1533 1638 1455 4871

MDL = 5 µS/cm


Table B-8 : Carbonaceous BOD5 (mg/L)

Date Outlet of Outlet of Outlet of % Removal Outlet of

Holding HSSF CW Aerated in Aerated Phosphex

Tank Cell VSSF EW Cell Cell

Cell

Week 1 27-Jan-10 169 52 37 28.10% <1

Week 2 3-Feb-10 202 85 37 56.54% <1

Week 15 5-May-10 59 63 10 83.70% <1

Week 16 12-May-10 92 76 9 87.88% <1

Week 17 19-May-10 79 94 32 66.29% <1

Week 18 27-May-10 60 51 4 92.23% <1

Week 19 2-Jun-10 124 85 13 84.22% <1

Week 20 8-Jun-10 49 30 10 65.67% <1

Week 21 16-Jun-10 91 32 11 67.40% <1

Week 22 23-Jun-10 43 20 10 49.83% <1

Week 23 29-Jun-10 30 17 8 51.66% <1

Week 24 6-Jul-10 34 9 6 30.53% <1

Week 25 14-Jul-10 18 18 3 83.48% <1

Week 26 20-Jul-10 10 6 4 33.97% <1

Week 27 28-Jul-10

5 2 1 62.07% <1

Week 28 4-Aug-10

16 15 6 60.53% <1

Week 29 10-Aug-10

25 15 10 33.31% <1

Week 30 18-Aug-10

20 12 5 55.78% <1

Week 31 31-Aug-10

9 9 5 44.49% <1


45 33 9 73.37% <1

MDL = 1 mg/L


Table B-9 : Chemical Oxygen Demand (mg/L)

Date Outlet of Outlet of Outlet of % Removal Outlet of

Holding HSSF CW Aerated in Aerated Phosphex

Tank Cell VSSF EW Cell Cell

Cell

Week 1 27-Jan-10 332 273 65 76.2% 112

Week 2 3-Feb-10 335 240 64 73.5% 88

Week 15 5-May-10 109 128 38 70.6% 36

Week 16 12-May-10 118 82 30 63.6% 32

Week 17 19-May-10 167 85 50 40.4% 24

Week 18 27-May-10 131 89 26 70.6% 30

Week 19 2-Jun-10 174 76 19 75.0% 36

Week 20 8-Jun-10 128 71 25 65.4% 31

Week 21 16-Jun-10 123 59 24 59.8% 33

Week 23 29-Jun-10 90 46 18 60.7% 17

Week 24 6-Jul-10 118 49 23 53.0% 27

Week 25 14-Jul-10 73 44 18 59.4% 33

Week 26 20-Jul-10 104 74 52 29.5% 61

Week 27 28-Jul-10

41 46 22 52.2% 32

Week 28 4-Aug-10

60 38 20 46.0% 33

Week 29 10-Aug-10

66 39 19 50.8% 34

Week 30 18-Aug-10

73 45 20 55.7% 27

Week 31 31-Aug-10

53 38 21 45.5% 34

Week 32 8-Sep-10

75 35 21 41.5% 21


100 61 26 57.3% 32

MDL = 3 mg/L


Table B-10 : Ammonia Nitrogen (mg/L)

Date Outlet of Outlet of Outlet of % Removal in Outlet of

Holding HSSF CW Aerated Aerated Phosphex

Tank Cell VSSF EW VSSF EW Cell

Cell Cell

Week 1 27-Jan-10 84.80 64.40 10.40 83.85% 58.60

Week 2 3-Feb-10 85.40 60.80 8.00 86.84% 49.60

Week 15 5-May-10 26.60 55.00 0.80 98.55% 4.60

Week 16 12-May-10 15.00 20.50 0.30 98.54% 4.20

Week 17 19-May-10 31.60 25.20 0.40 98.41% 5.50

Week 18 27-May-10 29.40 39.80 <0.02 ~100% 5.60

Week 19 2-Jun-10 44.90 40.00 0.06 99.85% 8.00

Week 20 8-Jun-10 42.10 39.00 <0.02 ~100% 2.50

Week 21 16-Jun-10 46.30 34.30 <0.02 ~100% 4.73

Week 22 23-Jun-10 49.80 31.40 <0.02 ~100% 2.30

Week 23 29-Jun-10 39.20 17.80 <0.02 ~100% 5.30

Week 24 6-Jul-10 28.50 30.40 <0.02 ~100% 2.80

Week 25 14-Jul-10 28.00 27.20 <0.02 ~100% 3.36

Week 26 20-Jul-10 32.46 24.99 0.08 99.68% 2.77

Week 27 28-Jul-10

20.20 21.40 <0.02 ~100% 1.58

Week 28 4-Aug-10

28.80 28.00 0.03 99.89% 2.30

Week 29 10-Aug-10

25.80 22.00 <0.02 ~100% 1.82

Week 30 18-Aug-10

23.80 16.60 0.27 98.37% 1.44

Week 31 31-Aug-10

15.50 15.90 0.20 98.74% 1.30

Week 32 8-Sep-10

26.70 12.50 0.07 99.44% 0.19


30.81 27.89 0.12 99.56% 3.35

MDL = 0.02 mg NH3-N/L by Hach


Table B-11 : Nitrate Nitrogen (mg/L)




Cell

Week 1 27-Jan-10 ND 11.55 61.51 9.88

Week 2 3-Feb-10 ND ND 63.10 2.98

Week 15 5-May-10 4.37 0.03 63.98 59.04

Week 16 12-May-10 0.05 ND 45.71 40.75

Week 17 19-May-10 ND ND 46.90 40.61

Week 18 27-May-10 0.10 ND 23.34 27.68

Week 19 2-Jun-10 ND ND 38.05 36.13

Week 20 8-Jun-10 0.12 ND 40.42 30.59

Week 21 16-Jun-10 ND ND 36.83 39.06

Week 22 23-Jun-10 0.29 0.04 35.60 35.10

Week 23 29-Jun-10 0.58 0.23 36.12 34.94

Week 24 6-Jul-10 ND ND 39.18 33.10

Week 25 14-Jul-10 0.56 ND 33.95 30.12

Week 26 20-Jul-10 0.09 ND 29.44 28.42

Week 27 28-Jul-10

0.52 <0.05 26.65 23.44

Week 28 4-Aug-10

0.67 <0.05 25.07 25.81

Week 29 10-Aug-10

<0.05 <0.05 22.12 23.39

Week 30 18-Aug-10

<0.05 <0.05 20.57 20.85


0.47 <0.05 35.24 33.06

MDL = 0.05 mg NO3-N/L by Ion Chromatograph


Table B-12 : Nitrite Nitrogen (mg/L)




Cell

Week 1 27-Jan-10 ND ND 2.52 1.86

Week 2 3-Feb-10 ND ND 1.06 1.25

Week 15 5-May-10 1.37 ND 1.38 1.64

Week 16 12-May-10 ND ND ND 2.29

Week 17 19-May-10 ND ND ND 1.99

Week 18 27-May-10 0.14 ND ND 2.13

Week 19 2-Jun-10 3.19 ND ND 5.47

Week 20 8-Jun-10 ND ND ND 5.66


Week 22 23-Jun-10 ND ND 0.82 1.95


Week 24 6-Jul-10 ND ND ND 5.09



Week 27 28-Jul-10

0.43 <0.05 <0.05 6.41

Week 28 4-Aug-10

0.75 <0.05 <0.05 5.91

Week 29 10-Aug-10

<0.05 <0.05 <0.05 4.56

Week 30 18-Aug-10

<0.05 <0.05 <0.05 3.17


0.38 <0.05 <0.05 4.30

MDL = 0.05 mg NO2-N/L by Ion Chromatograph ND = non-detect


Table B-13 : Total Coliforms (cfu/100 mL)




Cell

Week 1 27-Jan-10 n/a, overgrown 1270 136 <3

Week 2 3-Feb-10 694000 50 76 <3

Week 15 5-May-10 156000 <24240 <2424 <3

Week 16 12-May-10 1174000 19000 <1500 <3

Week 17 19-May-10 1238000 18000 500 <3

Week 18 27-May-10 4848000 41800 220 <3

Week 19 2-Jun-10 430000-280000 3800 360 <3

Week 20 8-Jun-10 152000 6500 213 30

Week 21 16-Jun-10 1717333 14783 133 <3

Week 22 23-Jun-10 339000 15850 200 <3

Week 23 29-Jun-10 469000 80600 33 <3

Week 25 14-Jul-10 194000 4700 52 8

Week 27 28-Jul-10

3800 3800 49 <3

Week 28 4-Aug-10

177000 70000 114 <3

Week 29 10-Aug-10

85800 46600 98 <3

Week 30 18-Aug-10

938000 9800 87 <3

Week 31 31-Aug-10

434000 3270 1038 <3

Week 32 8-Sep-10

938000 10380 654 <3

MDL = 3 cfu/100mL

n/a = not analyzed


Table B-14 : E Coli (cfu/100 mL)




Cell

Week 1 27-Jan-10 n/a, overgrown 300 3 11

Week 2 3-Feb-10 307000 50 16 <3

Week 15 5-May-10 49000 2470 141 <3

Week 16 12-May-10 146000 3000 <1500 <3

Week 17 19-May-10 158000 2200 <60 <3

Week 18 27-May-10 78000 5900 <30 <3

Week 19 2-Jun-10 <30000 <600 15 <3

Week 20 8-Jun-10 32000 300 11 <3

Week 21 16-Jun-10 174000 950 <60 <3

Week 22 23-Jun-10 52000 2950 13 <3

Week 23 29-Jun-10 136000 29200 <3 <3

Week 25 14-Jul-10 33000 150 <3 <3

Week 27 28-Jul-10

2200 1250 <3 <3

Week 28 4-Aug-10

94000 1250 8 <3

Week 29 10-Aug-10

3300 2200 5 <3

Week 30 18-Aug-10

55000 1000 8 <3

Week 31 31-Aug-10

59000 855 375 <3

Week 32 8-Sep-10

740000 5100 489 <3

MDL = 3 cfu/100mL


Table B-15 : Aluminum (µg/L)

Date MDL Outlet of Outlet of Outlet of Outlet of



Cell

Week 1 27-Jan-10 0.149 4.622 <MDL 139.4 23.69

27-Jan-10 10 20.4 15.9 16.6 23.2

Week 2 3-Feb-10 0.149 <MDL <MDL 1.512 19.31

3-Feb-10 10 21.5 13.5 25.3 29.5

Week 11 6-Apr-10 0.155 <MDL 1.393 1.262 <MDL

13-Apr-10 0.155 6.692 6.282 2.507 <MDL

Week 14 30-Apr-10 0.155 <MDL <MDL <MDL <MDL

Week 15 5-May-10 10 44.2 12.3 13.8 <10

Week 16 12-May-10 10 20.4 <10 25.5 <10

Week 17 19-May-10 10 27.4 <10 26.6 <10

21-May-10 0.155 <MDL <MDL 36.27 <MDL

Week 18 27-May-10 10 11.0 <10 36.3 <10

Week 19 2-Jun-10 10 16.3 <10 50.9 33.5

Week 20 8-Jun-10 10 42.4 <10 59.9 <10

Week 21 16-Jun-10 10 14.7 <10 37.5 89.5

18-Jun-10 0.155 <MDL <MDL 23.91 <MDL

Week 22 23-Jun-10 10 <10 <10 21.3 <10

Week 23 29-Jun-10 10 <10 <10 31.3 <10

Week 24 6-Jul-10 10 <10 <10 39.0 12.2

Week 25 14-Jul-10 10 <10 <10 33.4 56.9

Average Weeks 15-25

15.1 4.8 33.5 17.5


Method:

ICP-MS (UoW) ICP-OES (CAWT)

PWQO: 75 µg/L

CKL Sewer Use ByLaw Limit: 50 mg/L


Table B-16 : Vanadium (µg/L)




Cell

Week 1 27-Jan-10 0.022 <MDL 0.417 13.19 10.45

27-Jan-10 5 <5 <5 15.3 <5

Week 2 3-Feb-10 0.022 <MDL 0.42 13.76 0.229

3-Feb-10 5 <5 <5 14.6 <5

Week 11 6-Apr-10 0.026 0.479 0.74 7.137 5.491

13-Apr-10 0.026 1.317 1.039 6.321 4.671

Week 14 30-Apr-10 0.026 1.072 0.111 7.402 7.239

Week 15 5-May-10 5 <5 <5 10.5 <5

Week 16 12-May-10 5 <5 <5 10.9 <5

Week 17 19-May-10 5 <5 <5 12.8 <5

21-May-10 0.026 <MDL 0.133 11.86 3.615

Week 18 27-May-10 5 <5 <5 11.7 <5

Week 19 2-Jun-10 5 <5 <5 13.5 <5

Week 20 8-Jun-10 5 <5 <5 12.5 <5

Week 21 16-Jun-10 5 <5 <5 10.6 <5

18-Jun-10 0.026 0.163 0.318 10.22 3.797

Week 22 23-Jun-10 5 <5 <5 10.1 <5

Week 23 29-Jun-10 5 <5 <5 8.2 5.3

Week 24 6-Jul-10 5 <5 <5 11.5 <5

Week 25 14-Jul-10 5 <5 <5 8.9 <5

Average Weeks 15 - 25

2.13 2.11 11.02 2.90


Method:


PWQO: 6 µg/L

CKL Sewer Use ByLaw Limit: none


Table B-17 : Zinc (µg/L)




Cell

Week 1 27-Jan-10 0.098 9.841 4.499 6.471 29.8

27-Jan-10 3 15.4 4.8 4.3 <3

Week 2 3-Feb-10 0.098 3.52 1.992 2.82 0.083

3-Feb-10 3 19.5 <3 <3 <3

Week 11 6-Apr-10 0.254 9.201 5.333 6.816 19.5

13-Apr-10 0.254 4.332 8.048 9.742 0.79

Week 14 30-Apr-10 0.254 3.614 1.03 2.321 1.06

Week 15 5-May-10 3 12.4 7.9 5.2 <3

Week 16 12-May-10 3 16.7 6.6 <3 <3

Week 17 19-May-10 3 28.9 6.5 <3 <3

21-May-10 0.254 5.943 6.404 0.237 <MDL

Week 18 27-May-10 3 4.6 6.5 <3 <3

Week 19 2-Jun-10 3 14.1 <3 <3 <3

Week 20 8-Jun-10 3 4.1 <3 <3 <3

Week 21 16-Jun-10 3 11.5 <3 <3 <3

18-Jun-10 0.254 5.652 0.852 <MDL <MDL

Week 22 23-Jun-10 3 6.7 <3 <3 <3

Week 23 29-Jun-10 3 9.6 <3 28.3 <3

Week 24 6-Jul-10 3 6.1 <3 <3 <3

Week 25 14-Jul-10 3 4.0 6.7 <3 <3

Average Weeks 15-25

10.0 3.9 3.6 1.3


Method: ICP-MS (UoW) ICP-OES (CAWT)

PWQO: 20 µg/L



Table B-18 : Iron (µg/L)




Cell

Week 1 27-Jan-10 0.088 28.16 78.33 40.88 54.69

27-Jan-10 5 41.4 80.8 17.1 <5.0

Week 2 3-Feb-10 0.088 9.486 60 23.41 3.404

3-Feb-10 5 40.1 54.7 20.3 <5.0

Week 11 6-Apr-10 0.066 21.29 39.45 27.86 2.171

13-Apr-10 0.066 28.6 63.77 51.22 20.96

Week 14 30-Apr-10 0.066 24.93 81.64 57.28 4.74

Week 15 5-May-10 5 63.1 55.3 9.7 <5.0

Week 16 12-May-10 5 88.3 55.1 7.1 34.9

Week 17 19-May-10 5 76.8 38.9 <5.0 <5.0

21-May-10 0.066 48.08 48.84 28.22 <MDL

Week 18 27-May-10 5 40.1 35.0 <5.0 <5.0

Week 19 2-Jun-10 5 49.0 32.7 <5.0 <5.0

Week 20 8-Jun-10 5 78.7 65.3 5.6 <5.0

Week 21 16-Jun-10 5 60.6 71.8 <5.0 <5.0

18-Jun-10 0.066 60.58 77.55 1.367 <MDL

Week 22 23-Jun-10 5 51.5 76.9 5.8 7.8

Week 23 29-Jun-10 5 49.0 97.3 7.1 <5.0

Week 24 6-Jul-10 5 40.7 86.7 4.8 <5.0

Week 25 14-Jul-10 5 38.5 75.2 4.8 <5.0

Average Weeks 15-25

57.3 62.8 6.5 6.6


Method:


PWQO: 300 µg/L



Table B-19 : Manganese (µg/L)




Cell

Week 1 27-Jan-10 0.028 44.25 11.94 43.72 11.18

27-Jan-10 4 44.5 11.2 20.5 <4.0

Week 2 3-Feb-10 0.028 41.55 14.01 22.02 <MDL

3-Feb-10 4 43.0 12.7 19.9 <4.0

Week 11 6-Apr-10 0.035 15.78 25.45 101.7 0.042

13-Apr-10 0.035 17.2 39.08 139.7 2.127

Week 14 30-Apr-10 0.035 36.19 75.37 89.38 0.837

Week 15 5-May-10 4 36.0 39.5 <4.0 <4.0

Week 16 12-May-10 4 34.8 36.6 <4.0 <4.0

Week 17 19-May-10 4 46.5 36.4 <4.0 <4.0

21-May-10 0.035 53.87 54.7 <MDL <MDL

Week 18 27-May-10 4 30.6 46.4 <4.0 <4.0

Week 19 2-Jun-10 4 47.8 46.0 <4.0 <4.0

Week 20 8-Jun-10 4 55.0 57.8 <4.0 <4.0

Week 21 16-Jun-10 4 48.9 64.2 <4.0 <4.0

18-Jun-10 0.035 54.39 77.78 0.042 <MDL

Week 22 23-Jun-10 4 50.7 70.0 <4.0 <4.0

Week 23 29-Jun-10 4 41.9 69.6 <4.0 <4.0

Week 24 6-Jul-10 4 39.5 72.7 <4.0 <4.0

Week 25 14-Jul-10 4 29.3 55.2 <4.0 <4.0

Average Weeks 15-25

43.8 55.9 1.7 1.7


Method:


PWQO: none



Table B-20 : Chromium (µg/L)




Cell

Week 1 27-Jan-10 0.027 <MDL <MDL 0.893 12.74

27-Jan-10 3 <3.0 <3.0 3.20 <3.0

Week 2 3-Feb-10 0.027 <MDL <MDL 0.571 0.917

3-Feb-10 3 <3.0 <3.0 <3.0 <3.0


13-Apr-10 0.052 <MDL 0.256 <MDL <MDL

Week 14 30-Apr-10 0.052 <MDL <MDL <MDL 0.588

Week 15 5-May-10 3 <3.0 <3.0 <3.0 <3.0

Week 16 12-May-10 3 <3.0 <3.0 <3.0 <3.0

Week 17 19-May-10 3 3.54 <3.0 <3.0 <3.0

21-May-10 0.052 <MDL <MDL <MDL <MDL

Week 18 27-May-10 3 <3.0 <3.0 <3.0 <3.0

Week 19 2-Jun-10 3 <3.0 <3.0 <3.0 <3.0

Week 20 8-Jun-10 3 <3.0 <3.0 <3.0 <3.0

Week 21 16-Jun-10 3 <3.0 <3.0 <3.0 <3.0

18-Jun-10 0.052 <MDL <MDL <MDL <MDL

Week 22 23-Jun-10 3 <3.0 <3.0 <3.0 <3.0

Week 23 29-Jun-10 3 <3.0 <3.0 <3.0 <3.0

Week 24 6-Jul-10 3 <3.0 <3.0 <3.0 <3.0

Week 25 14-Jul-10 3 <3.0 <3.0 <3.0 <3.0

Average Weeks 16-25

<MDL <MDL <MDL <MDL


Method:


PWQO: 8.9 µg/L



Table B-21 : Copper (µg/L)




Cell

Week 1 27-Jan-10 0.026 4.911 4.488 29.14 27.45

27-Jan-10 5 7.1 <5.0 26.7 12.2

Week 2 3-Feb-10 0.026 2.845 3.741 20.78 22.05

3-Feb-10 5 6.6 <5.0 17.7 12.7

Week 11 6-Apr-10 0.040 8.316 3.94 17.02 11.42

13-Apr-10 0.040 9.112 3.878 14.55 11.53

Week 14 30-Apr-10 0.040 4.538 2.606 12.38 9.889

Week 15 5-May-10 5 23.9 8.9 25.0 9.6

Week 16 12-May-10 5 25.2 5.7 17.2 10.9

Week 17 19-May-10 5 5.4 17.1 10.7

21-May-10 0.040 9.653 2.367 15.86 7.974

Week 18 27-May-10 5 8.4 5.4 15.2 10.6

Week 19 2-Jun-10 5 38.3 <5.0 18.2 9.0

Week 20 8-Jun-10 5 9.7 <5.0 17.1 6.8

Week 21 16-Jun-10 5 10.5 <5.0 13.3 7.8

18-Jun-10 0.040 6.511 1.955 14.5 7.753

Week 22 23-Jun-10 5 12.8 6.2 27.0 6.9

Week 23 29-Jun-10 5 14.3 <5.0 6.0

Week 24 6-Jul-10 5 17.5 <5.0 12.7 7.0

Week 25 14-Jul-10 5 18.5 <5.0 12.4 7.7

Average Weeks 15 - 25

16.3 3.9 15.8 8.4


Method:


PWQO: 6 µg/L



Table B-22 : Nickel (µg/L)




Cell

Week 1 27-Jan-10 0.027 2.554 4.355 4.626 41.71

27-Jan-10 6 <6.0 <6.0 <6.0 27.8

Week 2 3-Feb-10 0.027 2.588 3.461 4.321 27.97

3-Feb-10 6 <6.0 <6.0 <6.0 24.7

Week 11 6-Apr-10 0.035 6.595 3.113 3.698 9.845

13-Apr-10 0.035 6.519 3.459 4.28 9.006

Week 14 30-Apr-10 0.035 3.795 2.689 2.912 8.726

Week 15 5-May-10 6 <6.0 <6.0 <6.0 9.2

Week 16 12-May-10 6 <6.0 <6.0 <6.0 8.8

Week 17 19-May-10 6 <6.0 <6.0 <6.0 9.2

21-May-10 0.035 3.189 3.795 2.125 16.12

Week 18 27-May-10 6 <6.0 <6.0 <6.0 17.4

Week 19 2-Jun-10 6 <6.0 <6.0 <6.0 33.9

Week 20 8-Jun-10 6 <6.0 <6.0 <6.0 14.3

Week 21 16-Jun-10 6 <6.0 <6.0 <6.0 37.7

18-Jun-10 0.035 3.657 2.881 2.032 17.04

Week 22 23-Jun-10 6 <6.0 <6.0 <6.0 17.1

Week 23 29-Jun-10 6 <6.0 <6.0 <6.0 9.8

Week 24 6-Jul-10 6 <6.0 <6.0 <6.0 27.6

Week 25 14-Jul-10 6 <6.0 <6.0 <6.0 36.5

Average Weeks 15-25

3.1 3.1 2.9 19.6


Method: ICP-MS (UoW) ICP-OES (CAWT)

PWQO: 25 µg/L



Table B-23 : Lead (µg/L)




Cell

Week 1 27-Jan-10 0.008 <MDL <MDL 3.774 13.75

27-Jan-10 50 <50.0 <50.0 <50.0 <50.0

Week 2 3-Feb-10 0.008 4.251 5.088 0.074 8.268

3-Feb-10 50 <50.0 <50.0 <50.0 <50.0

Week 11 6-Apr-10 0.012 <MDL <MDL <MDL 0.328

13-Apr-10 0.012 <MDL <MDL <MDL <MDL


Week 15 5-May-10 50 <50.0 <50.0 <50.0 <50.0

Week 16 12-May-10 50 <50.0 <50.0 <50.0 <50.0

Week 17 19-May-10 50 <50.0 <50.0 <50.0 <50.0

21-May-10 0.012 <MDL <MDL <MDL 0.689

Week 18 27-May-10 50 <50.0 <50.0 <50.0 <50.0

Week 19 2-Jun-10 50 <50.0 <50.0 <50.0 <50.0

Week 20 8-Jun-10 50 <50.0 <50.0 <50.0 <50.0

Week 21 16-Jun-10 50 <50.0 <50.0 <50.0 <50.0

18-Jun-10 0.012 <MDL <MDL <MDL 0.136

Week 22 23-Jun-10 50 <50.0 <50.0 <50.0 <50.0

Week 23 29-Jun-10 50 <50.0 <50.0 <50.0 <50.0

Week 24 6-Jul-10 50 <50.0 <50.0 <50.0 <50.0

Week 25 14-Jul-10 50 <50.0 <50.0 <50.0 <50.0

Average Weeks 15-25

<MDL <MDL <MDL <MDL


Method:


PWQO: 5 µg/L



Table B-24 : Titanium (µg/L)




Cell

Week 1 27-Jan-10 0.003 <MDL <MDL <MDL 12.13

27-Jan-10 5 <5.0 <5.0 <5.0 <5.0

Week 2 3-Feb-10 0.003 <MDL <MDL <MDL <MDL

3-Feb-10 5 <5.0 <5.0 <5.0 <5.0




Week 15 5-May-10 5 <5.0 <5.0 <5.0 <5.0

Week 16 12-May-10 5 <5.0 <5.0 <5.0 <5.0

Week 17 19-May-10 5 <5.0 <5.0 <5.0 <5.0


Week 18 27-May-10 5 <5.0 <5.0 <5.0 <5.0

Week 19 2-Jun-10 5 <5.0 <5.0 <5.0 <5.0

Week 20 8-Jun-10 5 <5.0 <5.0 <5.0 <5.0

Week 21 16-Jun-10 5 <5.0 <5.0 <5.0 <5.0


Week 22 23-Jun-10 5 <5.0 <5.0 <5.0 <5.0

Week 23 29-Jun-10 5 <5.0 <5.0 <5.0 <5.0

Week 24 6-Jul-10 5 <5.0 <5.0 <5.0 <5.0

Week 25 14-Jul-10 5 <5.0 <5.0 <5.0 <5.0

Average Weeks 16-25

<MDL <MDL <MDL <MDL


Method:


PWQO: none



Table B-25 : Cadmium (µg/L)


Septic Vegetated Vegetated Phosphex

Tank Horizontal VSSF Cell

Cell EW Cell

Week 1 27-Jan-10 0.012 <MDL <MDL 0.068 12.41

27-Jan-10 0.2 0.31 <0.2 0.31 0.22

Week 2 3-Feb-10 0.012 <MDL 0.164 <MDL <MDL

3-Feb-10 0.2 0.36 0.31 0.27 <0.2




Week 15 5-May-10 0.2 0.06 <0.2 <0.2 0.32

Week 16 12-May-10 0.2 0.36 0.36 0.30 <0.2

Week 17 19-May-10 0.2 0.32 <0.2 <0.2 <0.2


Week 18 27-May-10 0.2 <0.2 0.29 <0.2 0.22

Week 19 2-Jun-10 0.2 0.27 <0.2 0.38 <0.2

Week 20 8-Jun-10 0.2 <0.2 <0.2 <0.2 <0.2

Week 21 16-Jun-10 0.2 <0.2 0.44 <0.2 <0.2


Week 22 23-Jun-10 0.2 <0.2 <0.2 <0.2 0.20

Week 23 29-Jun-10 0.2 0.29 <0.2 <0.2 <0.2

Week 24 6-Jul-10 0.2 <0.2 <0.2 <0.2 0.30

Week 25 14-Jul-10 0.2 0.27 <0.2 0.26 0.23

Average Weeks 16-25

<MDL <MDL <MDL <MDL


Method:


PWQO: 0.2 µg/L

CKL Sewer Use ByLaw Limit: 0.7 mg/L

APPENDIX C CONSTRUCTED WETLANDS

EW-Phosphex Project, Phase 1 Treatability Testing, 1221 10066/7 © Stantec, 2010

C-2

THE ECOLOGICAL FUNCTIONS OF WETLANDS

CONTROLLING AND STORING SURFACE WATER

RECHARGING AND DISCHARGING GROUNDWATER

AIDING IN FLOOD CONTROL

PROTECTING SHORELINES FROM EROSION

SUPPORTING AND INITIATING COMPLEX FOOD CHAINS

PROVIDING HABITAT AND VEGETATED AREAS

PROVIDING CORRIDORS FOR WILDLIFE MOVEMENT

TRAPPING SEDIMENTS WHICH MIGHT CLOG

WATERCOURSES

MAINTAINING AND IMPROVING WATER QUALITY

IMMOBILIZING SOME CONTAMINANTS AND NUTRIENTS

C.1 Wetlands

Wetlands are ubiquitous. They are found in flat, protected, tidally-inundated areas. They are found next to freshwater streams, lakes and floodplains, and in surface depressions everywhere. Wetlands can be defined as lands, which are seasonally or permanently inundated by shallow water. In them the presence of abundant water causes the formation of hydric soils (those which are saturated with water and are anaerobic in nature) and favours the dominance of either hydrophytic (water-loving), or water-tolerant rooted and floating plants. Wetlands are biologically extremely diverse. This is because of their sensitivity to water level. Seasonal and annual variations can dramatically alter vegetation, microbial communities and wildlife in and around a wetland. These alterations stress the ecosystem but also provide a series of ecological niches, which support a variety of flora and fauna (Hammer, 1997). Wetlands have commercial and utilitarian functions. These include aesthetic, educational and other social values. They also can be sources of crops such as wild rice and cranberries, fur-bearing animals, fish and shellfish. The productivity of many wetlands exceeds most fertile farm fields as they receive, hold and recycle nutrients continually washed into them from higher, drier ground. The box below lists some of the ecological functions of wetlands. It is the last few of them that especially interest engineers. Wetlands will remove a variety of materials from any water passing through them, including suspended and dissolved solids, some soluble salts and other compounds, pesticides and other biocides, undesirable micro-organisms, heavy metals, spilled fuels, oils & greases, and a host of other organic compounds. A wetland’s vegetation also will absorb and assimilate nutrients (nitrogen, phosphorus and potassium compounds) from water. The result is that many harmful and/or undesirable contaminants in the water are greatly reduced in quantity and much of them do not move further downstream from a wetland. This in turn reduces or eliminates many adverse environmental impacts. Wetlands therefore act as water treatment facilities. Algae and aquatic plants in wetlands release (“leak”) oxygen into their root zones as a by-product of their growth. This increases the dissolved oxygen content in the water and in the soil in the vicinity of plant roots, thereby allowing aerobic microbial reactions to occur more readily, supplementing the anaerobic ones normal in hydric soils. Accordingly, wetlands can be used to treat contaminants which enter them in sewage streams, leachates, food wastes, wastewaters from industries, other disposals, spills, and/or as surface runoff from non-point pollution sources (e.g., mines, agricultural areas, urban streets). The impacts of such discharges on the wetlands can be highly variable, but in spite of often-rapid changes in the quantity and quality of waters passing through them, they function well as pollution removal mechanisms.


C-3

C.2 Natural Wetlands

As was mentioned, Natural Wetlands are those areas wherein, at least periodically, the land supports predominantly hydrophytes (and whose substrate is predominantly un-drained hydric soils and are saturated with water or covered by shallow water at some time during the growing season each year. Flooding-intolerant vegetation is absent from them. Natural Wetlands are found in surface depressions, and alongside streams, lakes and the sea everywhere; they often provide the interfaces between fully aquatic and terrestrial ecosystems. Waters in Natural Wetlands are generally less than two meters deep (and often very much shallower), and may stand/flow both on the surface and sub-surface in/via soils and substrates. Regular to erratic drying cycles may occur in all or part of Natural Wetlands. Water level fluctuations are normal in them, and morphologies usually are complex, with many flow channels, backwaters, and other heterogeneous areas. Around the world, there are many names for different kinds of Natural Wetlands (e.g., They can be called marshes, tidal marshes, billabongs, carrs, mires potholes, sloughs, fens, wet meadows, playas, and vernal pools when their vegetation is not woody, or swamps (forested wetlands) and mangrove swamps when it is. They can occur as ponds in low lying, upland areas fed by springs and/or precipitation, and in arctic areas as bogs where permafrost dominates their ecosystems. The official designations for them in Canada are: marshes, swamps, bog, fens and shallow open water wetlands. Bogs are peat-covered low/no flow areas dominated by Sphagnum moss and other ombiotrophic (isolated from water sources other than precipitation) and acidophilic (thriving under acidic conditions) vegetation. Waters in bogs are low in pH, calcium, magnesium and nutrients (nitrogen and phosphorus compounds). While moss and similar herbaceous plants are the most prevalent vegetation, where conditions allow, some shrubs, low bushes and trees such as white cedar, tamarak and black spruce may grow in them too. Fens are another kind of peatland typified by high water tables and slow internal drainage. Like bogs, herbaceous plants are the dominant vegetation in them (e.g., leather leaf), although a few shrubs (e.g., bog rosemary) and trees (e.g., willows) also may be present. Waters in fens tend to be mineral rich. Marshes are areas permanently or periodically inundated and dominated by stands of emergent herbaceous vegetation such as cattails and reeds. Waters in them are neutral in pH, relatively high in dissolved oxygen and nutrients, and are generally moving. Open water areas in them may also contain floating plants (e.g., duckweed) and submergent plants (e.g., wild celery). As with other herbaceous vegetation-dominated Natural Wetlands, a few bushes and trees may also grow in marshes. Swamps are wooded Natural Wetlands with water-logged sub-surface areas in which shrubs, bushes (e.g., willow, dogwood) and trees (e.g., white cedar) are the dominant vegetation, although some herbaceous plants are usually present among them. Waters in swamps tend to be standing or slowly moving most of the time. Shallow Open Water Wetlands are ponds (potholes, sloughs, depressional basins) of standing or flowing water transitional between lakes and marshes. They often have


C-4

emergent herbaceous plants growing on their peripheries and in shallower areas, and floating and submergent vegetation in the open water. Natural Wetlands are biologically extremely diverse. Seasonal and annual variations in a wetland can dramatically alter vegetation, microbial communities and wildlife in and around the wetland. Natural wetlands are ecologically important as they: provide habitat and corridors for wildlife movement; aid in flood control; protect shorelines from erosion; control and store surface water; trap sediments; immobilize contaminants and nutrients; and maintain and improve water quality. Over 45% of all Natural Wetlands lie above 45º North Latitude, and these are largely tundra, muskeg, taiga and coastal marsh wetlands. Prior to division of Nunavut from the Northwest Territories, the territories had the second highest total of natural wetland area in Canada, second only to Ontario. It is important to note that the addition of a wastewater to a Natural Wetland will dramatically alter its ecology and biology. Temperature, flow regime, pH, water levels, plant growth/speciation, etc. will change. Nutrient-deficient, standing-water ones such as bogs may be converted into flowing systems and the plants in them will proliferate in the new positively stressed conditions that favour their growth.

C.3 Treatment Wetlands

There are two basic varieties of wetlands: Natural ones and Artificial ones deliberately built by people. Wetlands of either type used to treat wastewater are referred to as Treatment Wetlands (Moshiri, 1993). These are attached-growth treatment reactors that support the growth of emergent wetland plants such as cattails, bulrushes, reeds and sedges. The vegetation provides surface for the attachment of bacterial biofilms, aids in the filtration and adsorption of wastewater contaminants; transfers oxygen into the water column; and, for open water surface wetland systems, controls the growth of algae by restricting the penetration of sunlight. Although plant uptake is a consideration in nutrient removal, it is only one of many active removal mechanisms in a wetland environment. Removal mechanisms can be classified as physical, chemical and biological, and are operative in the water column, in the humus and soil column beneath the growing plants, and at the interface between the water and soil columns. Since most of the biological transformations take place on or near a surface to which bacteria are attached as biofilms, the presence of vegetation and humus is very important. Natural wetlands are generally used for wastewater treatment only if they already exist convenient to a wastewater source. Natural wetlands have been used for millennia to dispose of sewage. The first recorded deliberately designed use of a natural wetland for municipal sewage treatment began at a natural freshwater wetland at Great Meadows, MA on the Concord River in the U.S. in 1912 (Kadlec & Knight, 1996). In Canada, from 1919 on, sewage effluent from the Dundas, Ontario wastewater treatment plant has been directed into the Cootes Paradise natural wetland at Hamilton, ON on the west end of Lake Ontario. Both fresh and saltwater marshes in Florida have been (since 1939) and still are, used for municipal sewage treatment. The Town of Houghton Lake in Michigan, USA has been using a local fen for sewage disposal since 1978 and this much studied and monitored system continues to operate well (Kadlec & Knight, 1996).


C-5

An important northern kind of Arctic Natural Treatment Wetland is the Tundra Wetland, a kind of bog/pond mixed wetland. (The term Tundra Wetland was proposed by Stantec and is now used by the governments of the Northwest Territories and Nunavut to describe any Natural Treatment Wetland in the Arctic.) Tundra Wetlands may be viewed as almost the natural analogues of the marsh-pond-marsh configuration of Constructed Wetlands often used in past, and consist of combinations of boggy areas and small ponds. The latter are spongy accumulations of living and dead Sphagnum moss, lichens and other vegetation, the dead plants usually only partly decomposed. Water flow through these areas is partially sub-surface and partly via surface channels. The other aspect of Tundra Wetlands is numerous shallow ponds that have no drainage to groundwater in the short summers due to underlying permafrost. Frost heaving during winter creates ridges and depressions with unique polygon configurations. In summer in the north, long days lead to the proliferation of algae in tundra wetland ponds, and photosynthesis leads to highly oxic conditions in them. Stantec is carrying out Tundra Wetland projects in the hamlets of Coral Harbour, Baker Lake and Chesterfield Inlet, all in Nunavut.

C.4 Constructed Wetlands

There are two kinds of Artificial Wetlands deliberately built by people: Created Wetlands and Constructed Wetlands. Created Wetlands are those wetlands built for purposes other than wastewater treatment (e.g., recreation, habitat creation, mitigation) (Hammer, 1997), while constructed wetlands are built to treat wastewaters. There are two kinds of constructed wetlands: those used for controlling stormwater quality (Stormwater Wetlands), and those used for managing wastewater quality (pollution control). Generally the term, Constructed Wetland (CW), refers to the latter, ones used for wastewater treatment, and not to ones used for stormwater management.

C.5 Stormwater Wetlands

Stormwater Wetlands are used for stormwater management and their main purpose is the control of water volumes. The removal of pollutants from the water passing through them usually is of less concern. Although they give somewhat better removals of suspended solids than do the alternative end-of-pipe stormwater management technologies such as dry or wet ponds (which many categorize as kinds of stormwater wetlands anyway), they still only provide moderate removals of suspended stormwater contaminants, and little removal of dissolved ones. Many Stormwater Wetlands consist of a large inlet forebay (a deep pool to settle out particles and sediment); a downstream marshy area in which wetland plants are growing (to filter out some suspended solids, and often divided into low and high marsh sectors); an outlet micro-pool; some sort of inlet and outlet control structures to manage water flows; and a wet meadow plant-vegetated riparian buffer area around the basins which may serve as an extended detention area. Stormwater wetland basins and ponds are more likely than CWs to be designed with irregular shapes and can be vegetated with biodiverse local plants. Various morphologies for Stormwater Wetlands are possible including shallow marsh


C-6

wetlands, pocket wetlands, extended detention wetlands, and pond-wetland versions, and as was mentioned, dry ponds and wet ponds for some. Typically, Stormwater Wetlands can remove about 50% of suspended solids in waters passing through them, up to 45% of the total phosphorus (mostly that associated with the suspended solids), up to 25% of total nitrogen (again mostly that associated with the suspended solids), up to 15% of organic carbon in the water being treated, and varying levels of metals and pathogens (again depending mostly on how much of these are associated with removable solids). Stormwater Wetlands are not effective for removing contaminants of a dissolved or colloidal nature. Stormwater Wetlands are designed to manage precipitation from storm events and flows of this runoff can vary from zero (or some low base flow) to very high flow levels over relatively short periods. This is consistent with their major role, which is to delay stormwater flows, preventing the discharge of the stormwater into receiving waters too quickly. This is in contrast to flows through Treatment Wetlands which usually are equalized and controlled within narrow limits.

C.6 Constructed Treatment Wetlands

The modern use of constructed wetlands (CWs) for wastewater treatment began with seminal research at the Max Planck Institute in Germany in 1952. In North America, R&D on treatment wetlands began at the Tennessee Valley Authority and University of North Carolina in 1960s and expanded to the Universities of Florida and Michigan in the 1970s. The first modern CW pilot unit was built at the Brookhaven Institute in New York in 1973, and was followed by a full scale unit treating municipal sewage at Mount View in California later that year. The first constructed wetland system treating industrial wastewater went into service at the Amoco Refinery in Mandan, ND and operates to this day. The largest CW system in the world to date is an 1800 ha one at Kis-Balaton in Hungary. There are two 500+ ha ones in Florida (Kadlec & Knight, 1996). There are now thousands of CWs operating worldwide treating sewage, septage, stormwater, industrial effluents, leachates, agricultural runoff and many other streams. Their numbers are increasing almost exponentially. Constructed wetland technology is now well proven. There are textbooks on the subject (Kadlec & Wallace, 2008, Kadlec & Knight, 1996, Reed et al., 1995, Vymazal, 2001), and the systems can be designed and engineered with as much confidence as can the other types of biological units widely used in conventional (mechanical) wastewater treatment plants (WWTPs). Constructed wetlands usually consist of a number of individual rectangular and/or irregularly-shaped cells (artificially-constructed basins) connected in series or parallel and these often are surrounded by berms (dykes) of earth, rock or other materials. They contain structures (distributors, weirs, piping) to ensure good hydraulic dispersion, level and rate control, and collection. Additional open water areas, integral ponds and forebays may be involved, depending on the type and application. CW cells are usually associated with a variety of ancillaries (e.g., ditching, piping, pumps). CWs are often used in association with other types of WWT technology as part of integrated treatment systems. Ponds and lagoons are often associated with vegetated CW cells, both in front


C-7

of and behind them and may themselves be regarded as cells of the wetland system. Cascades, land treatment methods, and/or conventional wastewater treatment (WWT) units may also form part of a CW system. With CWs, hydrological conditions, vegetation specifically chosen for effectiveness with certain pollutants, and soil substrates engineered for various CWs may be used for habitat/recreation/mitigation, for handling stormwater quantity, and/or for pollution control. In Europe, for municipal wastewater treatment CWs often serve as secondary units downstream of primary (physical) treatment. In North America, it used to be more common to use them as tertiary (polishing) units downstream from lagoons and other, more conventional WWT facilities, but this is changing as the full capabilities of the technology become more apparent. The most common use now of CWs is for secondary treatment downstream of a septic tank. A trend towards the use of more passive, all natural treatment systems has seen the increased use of wetlands in treating much larger flows of municipal sewage, agricultural and industrial wastewaters, mine drainage and leachates.

C.7 Types of Constructed Wetlands

Three types of CWs may be defined:

POND

FREE WATER SURFACE (FWS)

SUB-SURFACE FLOW (SSF) Pond Wetlands, as the name suggests, are simple shallow pools, usually vegetated with emergent wetland vegetation (e.g., cattails) around the peripheries (10 - 30% of area) and having some portion of their surface consisting of open water in which submergent and/or floating wetland vegetation is growing. They are most commonly used in conjunction with other types of wetlands cells (e.g., as re-aeration basins between FWS cells in the common marsh-pond-marsh system), or as parts of some kinds of stormwater wetland systems. Pond wetlands provide quiescent areas where sediments and some of the suspended solids in a wastewater can settle out. Hence, pond wetlands are good methods for dealing with any suspended solids, and the BOD, oil & grease, pesticides & herbicides, fertilizers, heavy metals and other organics which become associated with them in many wastewaters. Pond wetlands differ from lagoons in that they are almost always deliberately vegetated with wetland plants and most lagoons are not. In addition, they are usually shallower, and hence tend to be more aerobic (due to surface re-aeration) in contrast to usually deeper facultative lagoons which contain significant anaerobic zones. Where sediment loads are high, pond wetland cells can be provided with floating rafts of wetland plants and used in front of downstream FWS or SSF wetland cells. Floating plant raft pond wetlands allow settled sediments to be periodically easily removed and water levels to be varied without adversely impacting plant hydrology (NAWE, 2002). Floating reed beds are employed as part of a SSF CW system used at Heathrow Airport in the UK for treating glycol-contaminated stormwater (Worrall et al., 2002).


C-8

C.8 Free Water Surface Wetlands

Constructed wetlands of the Free Water Surface type (sometimes called Surface Flow wetlands) are marsh-type ones (US EPA, 2000) where water flows over the surface. They consist of relatively shallow, open basins containing water 0.1 to 0.3 metres (1 – 3’) deep. With FWS CWs, surface water surrounds emergent vegetation and there are often open water areas with submergent vegetation as well. In FWS CWs, the submerged portions of wetland plants as well as soil and detritus act as substrates for biofilm attachment, and the micro-organisms in these biofilms (largely bacteria) are responsible for much of the pollution removal. FWS CWs can be used for secondary municipal and industrial wastewater treatment, for advanced wastewater treatment, and for polishing or tertiary treatment. FWS constructed wetlands are the most common type of constructed wetland in North America and in tropical countries. FWS CWs can have areas of open water and are similar in appearance to natural marshes. When vegetation in them is dense, they can be largely anaerobic in nature (except near their water surfaces) but contain anaerobic zones and micro-environments. As decaying vegetation can maximize anaerobic conditions in FWS CWs, it is best to incorporate un-vegetated deeper, open water areas in them to balance out aerobic conditions too due to increased atmospheric diffusion. (Perpendicular deep zones also tend to smooth out flow through wetland cells.) FWS Wetlands are most commonly used to polish secondary effluents prior to surface water discharge, as receiving water bodies, and for stormwater treatment.

C.9 Sub-Surface Flow Wetlands

Sub-Surface Flow constructed wetlands are sometimes variously referred to as Vegetated Submerged Bed, Gravel Bed, Rock Reed Filter, Root Zone, or Reed Bed wetlands. With them, pollutant removal is via the substrate and plant root systems and, although wetland vegetation is apparent in them, their surfaces are largely dry. Generally, SSF wetlands consist of one or more beds of rock, gravel, sand, soil or engineered growth substrates. Beds in sub-surface flow wetlands can be easily replaced if clogging occurs but in most cases this would not be expected to occur for very many years (10+) in well-designed CW systems. Where potentially clogging suspended solids are found in a wastewater, pre-treatment to remove them is necessary before it is directed to SSF cells. SSF constructed wetlands are usually much smaller in area than FWS CWs for the same levels of pollutant removal, and can tolerate higher loadings. They are, however, generally more expensive, costing up to several times the cost of a FWS CW of equivalent size. (The higher capital cost is due the higher costs for designing and building them, especially for the cost of providing the substrate). SSF CWs are used where the wastewater being treated is noxious or odorous; where liquid sludges (e.g., sludges [biosolids] from a mechanical WWTP) need to be de-watered; where either very high or very low levels of dissolved metals and other contaminants need to be removed; where a higher degree of freeze protection is desired; where space (i.e., “footprint” area) is an important consideration; where the attraction of waterfowl may be undesirable (e.g., at airports); where ample, economic supplies of substrate material are readily available; and/or where operation in an engineered wetland mode is desired.


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There are two types of SSF CWs: those which are horizontally fed (HSSF, the most common) and in which the wastewater flows horizontally through the substrate; and those that are fed by applying wastewater either to their surfaces (downflow vertically fed, VSSF, it then percolates down to a buried effluent collection pipe below the substrate), or up from below (upflow VSSF wetlands). Some define VSSF CWs as Vertical Filter Beds (VSBs), a separate category of wetlands. It should be noted that constructed wetlands are LOW maintenance systems, not NO maintenance ones. This is especially true for SSF CWs and designers and operators should plan to cleanse or replace substrate beds every decade or so. (Such has not yet been found to be necessary with well-designed SSF CW systems that have been operating for many years, but prudent design and operations should allow for it.) Although cleaning or replacing the gravel substrate in a SSF CW cell would be onerous, its cost would be small on a net present value basis in comparison to the normal ongoing maintenance costs associated with alternative mechanical wastewater treatment plants.

C.10 Horizontal Sub-Surface Flow Wetlands

The most common type of SSF CW is the Horizontal Sub-Surface Flow variety. In HSSF CWs, the wastewater being treated enters the substrate bed at one end of the cell and flows generally horizontally across the cell parallel to the cell bottom. Bed thickness for HSSF CWs is usually from 0.5 – 0.8 m. This is the maximum depth to which the roots of the oxygen-leaking wetland plant roots can penetrate, and, were beds any thicker, some of the wastewater would flow below the plant roots, missing needed aerobic removal processes for oxidizable contaminants. As shown in the following table (Reed et al., 1995), maximum practical plant root depths normally limit the thickness of HSSF substrates.

Table C-1: Effect of Vegetation Root Depth on Ammonia Removal Efficiency in HSSF CWs

Root Penetration NH3-N Removal (% of way through substrate) (%)

100% 94

~50% 28

No Plants 11

Accordingly, unless the wetland plants’ roots penetrate to the bottom of the substrate layer in a HSSF wetland, some of the wastewater flowing through it will not be exposed to aerobic bacteria, and relevant microbial transformations will not occur in all of it. For the common constructed wetland plants, the maximum practical root penetration into a HSSF substrate is about 76 cm for bulrushes, somewhat over 60 cm for reeds, and only

30 cm for cattails (Reed et al. 1995). (Beds for Aerated HSSF EWs, see below, can be

any thickness as the oxygen needed is supplied from below the beds by blowers; generally the beds for them are 1.0 to 4.0 m thick.)

Influent can enter a HSSF CW cell either from a perforated pipe (or similar distributor) on the surface of the upstream end of the substrate bed (in which case its bulk flow pattern is sloping downwards towards the perforated outlet collection pipe usually buried


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at the base of the bed at the other end), or out from a buried inlet distributor. In any case, the wastewater being treated only “sees” the cross sectional area of the wetland bed and this limits the maximum flow that can be achieved (according to Darcy’s Law) and makes HSSF CWs more prone to plugging than are VSSF ones. Typically, SSF wetlands use substrate beds consisting of screened gravel or crushed rock, although early versions used soil (which readily plugged) (Kickuth, 1989), and some existing types use shales, peat, biosolids, compost as all or part of their substrates. As SSF CWs have no open water (water levels is usually maintained just below the substrate surface), atmospheric diffusion into them is even lower than that into Pond and FWS CWs (0 - 3 g-O2/m

2) (US EPA, 2000) which is usually small compared to the oxygen demand exerted by even a stormwater or dilute wastewater (NAWE, 2002). With poorly designed HSSF constructed wetlands, substrates can plug, resulting in the surfacing of wastewater flows. While this will lead to reduced performance, it is not always a disaster, as the failure mode of a HSSF CW is a FWS CW. Some CWs in northern regions operate in a FWS mode in summer and in a (more weather-resistant) HSSF mode during colder times.

C.11 Vertical Sub-Surface Flow (VSSF) Wetlands

Downflow VSSF CWs are variously referred to as Vertical Flow Constructed Wetlands (VFCWs), Reed Bed Filters (RBFs), Vertical Filter Beds, or Infiltration Beds. VSSF CWs treating sewage from small communities are becoming popular for the primary and secondary treatment of sewage from small communities (<500 person equivalents, Pe) in France, where often they operate in a pulse flow mode (intermittent dosing of multiple cells) and can involve two or three intermittently-dosed primary cells in parallel followed by two secondary cells in parallel. VSSF CWs are also often used in a continuous flow mode and in situations where wastewater flows are so high that hydraulic considerations preclude the HSSF morphology. There are also various kinds of upflow VSSF wetlands. In Brazil, a technology of this sort known as Filtering Soil is used. Another example of the downflow VSSF morphology is the Biosolids Stabilization Wetland (sometimes called a Reed Bed Wetland after the usual plant it will be vegetated with). These are increasingly being used as a method to economically condition, de-water and even degrade parts of the biosolids from activated sludge wastewater treatment plants using gravity and solar power. Downflow vertical sub-surface flow wetlands can be operated in two modes; saturated bed and freely draining bed. Fill & Drain VSSF wetlands are an example of the later and are operated by dosing a cell with a wastewater (usually sewage), then allowing the water to drain down through the bed while another cell is dosed. This draws oxygen into the bed, improving aerobic processes such as nitrification. Biosolids Stabilization Wetlands are another free drainage example. There are also various kinds of upflow VSSF wetlands. In Brazil, a technology of this sort known as Filtering Soil is used. Biochemical Reactors (BCRs, see below) are another example of a VSSF morphology often involving upflows. The following table compares vertical and horizontal sub-surface flow in wetlands.


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Table C-2: Comparison of VSSF & HSSF CWs

VSSF HSSF

cCell Shape Can be any shape Rectilinear cells preferable

WW Stratification Cannot occur Can occur

SS Removal Poorer Better

Nitrification Potential Better Poorer

De-Nitrification Potential Poorer Better

Substrate Layering Multiple layers possible Multiple layers will promote stratification, channelization

Hydraulic Capacity Higher Lower

If Clogging Occurs Easy to deal with Harder to deal with

It is emphasized that the comparisons in the above table are relative and will vary depending on the specific situation. For example, both VSSF and HSSF CWs can achieve very good suspended solids removals, but HSSF ones do a somewhat better job of doing so. Hybrid systems mixing VSSF and HSSF cells are becoming more common in some areas.

C.12 CW Vegetation

The most common types of emergent vegetation used in CWs in Europe and North America are cattails (Typha spp.), bulrushes (Scirpus spp.), and reeds (Phragmites spp.), although a variety of other wetland vegetation can be used as well. In all but the smallest CWs, monocultures usually are used rather than biodiverse vegetation as under the stressed conditions of a CW, the more “aggressive”, stress-resistant wetland plants (e.g., cattails) will quickly displace others if they are present. With FWS CWs, cattails and bulrushes are the most common types of emergent vegetation used in treatment wetlands. The most common type of plant used in SSF CWs is reeds, but cattails, bulrushes, reed canary grass (Pharis arundinacea) and managrass (Glyceria maxima) also have been used. In some cases SSF wetland cells are operated with no vegetation at all, especially for the early cells of a CW train, ones where the cells operate anaerobically, and/or in cases where relatively easy to degrade pollutants (e.g., low molecular weight alcohols) are the main contaminants being treated.

C.13 Pollutant Removal in CWs

Wastewaters usually contain a variety of pollutants, many of which are present in soluble (dissolved) and insoluble (particulate) forms. When such waters pass through a treatment wetland, a large portion of the particulate forms are removed by physical processes, but most of other pollutant removal is by microbially-mediated processes. A small portion of this may involve planktonic (floating) microorganisms, but the bulk occurs on and in the biofilms which cover all surfaces below the water level and permeate sediments, wetland soils and substrates. These biofilms consist of complex communities of aerobic, anaerobic and facultative bacteria, algae, and other microbes protected inside mucous. Even in biofilms in the most aerobic wetland areas, there are anaerobic micro-environments and vice versa.


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In pond and FWS CWs, the biofilm coats all underwater surfaces. In SSF CWs, the surfaces of the substrate particles of the beds are completely covered with remarkably permeable biofilms, and contaminants in a wastewater passing through are sorbed on/into this biofilm where the microbes interact with them. That part of the substrate bed that is penetrated by plant roots (the entire bed depth in CWs and part of it in EWs) forms a even more complex biofilm/root(let)s matrix. While some of the contaminants of wastewaters exist in discrete forms (dissolved single species such as ammonia), many others occur in a range of forms (e.g., dissolved, colloidal and particulate) and, for the latter, sizes (e.g., the particulates of suspended solids may exist in ranges of particle sizes and morphologies). These components are each removed at different rates in a wetland. Such types of pollutants are deemed lumped parameters. Examples are suspended solids, organic nitrogen, BOD, cBOD, total phosphorus, and many others. In addition, many other contaminants are preferentially associated with certain parts of a lumped parameter. For example, many metals, pathogens and organic materials are often found associated with or bound to mineral and organic particulates in wastewaters, and the removal of these suspended solids will also remove them. Suspended solids are usually quickly removed in treatment wetlands, often in the early parts of wetland cells by a variety of often inter-related processes such as settling, filtration, physical-chemical precipitation, sorption, and burial in sediments. Their removal leaves the non-particulate parts of other lumped parameter (e.g., the colloidal and dissolved components of organic nitrogen and BOD) to be removed more slowly later in the wetland. There are several ramifications to this. Bulk removal rate constants in wetlands for lumped parameters such as BOD, cBOD and organic nitrogen available from the literature may reflect the rapid and easy removals of the particulate parts, and may not be indicative of the [lower] rate constants representative of the remaining colloidal and dissolved components. This may be important for wetland design of advanced systems if such a component is the object of wetland treatment (e.g., a focus on the rate of removal of BOD in a glycol-contaminated airport stormwater runoff stream may be meaningless if the object is to remove its soluble glycol component). In general, in well-designed CW and EW systems, it is often preferable that the removals of the particulate portions of lumped parameters occur in upstream facilities, leaving the wetlands per se to deal with the more recalcitrant components. Most CWs are largely anaerobic in nature. In ordinary CWs, the amount of oxygen that can be supplied by plant root zone “leakage” is small and will suffice for the oxygen supply of aerobic removal mechanisms only in very lightly-loaded systems. In Pond and FWS CWs, oxygen supply is supplied mostly by that in the influent wastewater, atmospheric diffusion and algal photosynthesis. However, in SSF CWs the latter two mechanisms are very limited or absent, making them tend to be more anaerobic unless oxygen supply is augmented from external sources (see below). Vegetation in CWs (and some kinds of EWs) is capable of removing heavy metals from wastewaters passing through them by sorption (both abiotic and biotic) and by forming plaques in and around the root zones of the plants (Kadlec & Wallace, 2008). For metals of metabolic importance (Fe, Ni, Zn), minor amounts of the sorbed metals may be taken up (translocated) into plant tissue as well (Scholtz et al., 2002).


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While initially an SSF CW (or an EW) will sorb some dissolved phosphorus from a wastewater passing through it, and its biofilm will also take up more, once acclimatized, influent dissolved phosphorus can be expected to be virtually the same as that in its effluent (see Appendix E.6). SSF CWs (and EWs) are efficient scavengers of suspended solids and these can be expected to be largely removed in them. However, for many wastewater (e.g., sewage) the concentrations involved are so small (a few to a couple of tens of ppm) that there is little danger of plugging substrate beds with them. Nevertheless, Stantec advises its clients to take SSF CWs and EWs off-line every decade or so, to wash the gravel substrate before putting it back, a relatively simple and low cost procedure. More details omn phosphorus removal in wetlands is found in Appendix E.6

C.14 Aerobic Wetlands

The removal of many contaminants requires aerobic conditions (e.g., ammonia nitrification), and in many cases such removals require the provision of oxygen to aerobic microbes living symbiotically or opportunistically in the root zones of wetland plants (e.g., ammonia nitrification is a bacterially-mediated aerobic process). This can be difficult in the normally anaerobic environment below the water surface of CWs. As was discussed above, in them oxygen may come from that dissolved in the influent wastewater, from surface re-aeration, from “leakage” from the plant roots/rootlets in the root zone (such is the nature of many wetland plants), via the venturi effect through the hollow wetland plant stems (the reason aerobic reactions can continue in a CW even in winter), and/or artificially. All of these methods other than the artificial ones can only provide limited amounts of oxygen, and thus restrict ordinary CWs requiring the removal of oxidizable contaminants to low loading conditions (i.e., such wetlands will be large in size, have high water residence times, and in any case will only achieve limited removals of the oxidizable components). Accordingly, most ordinary CWs typically consist of cells in which aerobic and anaerobic processes take place simultaneously at different locations in the wetland at much lower efficiencies than would be possible in a cell where one type of process was optimized. However, there are methods to do just this - optimize one kind of condition (aerobic conditions or anaerobic conditions) and the multiple cells of a wetland system offer opportunities to do so in separate cells. A wetland involving enhanced oxic or aerobic conditions is known as an Aerobic Wetland, while one involving enhanced anoxic or anaerobic conditions is known as an Anaerobic Wetland. Both passive (CW) and semi-passive (EW) versions of Aerobic and Anaerobic Wetlands are possible, and a multi-cell treatment wetland system can contain one or more of either type of cell. Anaerobic Wetlands are kinds of SSF CWs (see below) while Aerobic Wetlands per se are kinds of FWS CWs. While all FWS CWs will have both aerobic and anaerobic zones and micro-environments of each mode, sparsely-vegetated FWS CWs with plenty of open water areas will be much more aerobic than anaerobic and can be defined as Aerobic Wetlands. Pond Wetlands also tend to be highly aerobic and also can be defined as Aerobic Wetlands and they depend on shallow water and surface re-aeration for their aerobic natures. Fill & Drain wetlands are kinds of EWs (see Appendix D.5) which involve periodically unsaturated substrate beds, and these therefore are aerobic for parts of their cycles.


C-14

C.15 Anaerobic Wetlands

There are three kinds of Anaerobic Wetlands:

ANAEROBIC SSF CWs

SUCCESSIVE ALKALINITY PRODUCING SYSTEMS (SAPS EWs)

ANAEROBIC BIOCHEMICAL REACTOR (BCR) EWs Heavily-vegetated FWS CWs with little or no open water also tend to be more anaerobic than aerobic. Any kind of anaerobic wetland can be expressed as a cell of an EW System. As with Aerobic Wetlands, Anaerobic Wetlands were first used by the Mining Industry to remove iron (and to a lesser extent manganese) from small streams and seeps, but in this case as sulphides in a reducing environment. In the bed, made up of an organic material such as compost mixed with limestone and from 0.1 to 0.3 m thick, any ferric iron (Fe3+) in the minewater is reduced to ferrous iron (Fe2+), which along with any other ferrous iron present, reacts with the H2S produced by the SRB to form an insoluble precipitate in the bed. (C.1)

Over time, the insoluble ferrous sulphide builds up in the bed. With Anaerobic Wetlands, acidic minewater was applied at the surface and flowed down through the substrate bed (i.e., VSSF) to collection distributors under the bed. The required size of these early SSF CWs was a function of metal loading, pH and alkalinity. Typical values for their sizings in past were 10 g Fe/m2/d or 2 g Mn/m2/d and they could tolerate up to 3.5 g of acidity/m2/d (Kadlec & Knight, 1996). Again, these simple Anaerobic Wetlands proved effective for metals removals only at low feedwater flow rates and only if the water was net acidic in this case. They are rarely used now for minewater treatment as they have been superceded by more efficient designs. However versions of them, sized using reactor-based models and modern design methods are still used and these are called Anaerobic SSF CWs (sometimes referred to as Compost Wetlands). Anaerobic SSF CWs, now designed by Stantec using modern methods and ancillaries, are not limited to treating ARD and neural mine drainage (NMD), and can be used to remove not only dissolved metals (and not just iron), as well as other contaminants (e.g., organics, nitrates), from a variety of wastewaters. They are designed as downflow VSSF cells and may be either vegetated or un-vegetated, with mixed organic/limestone substrates from 0.1 to 0.5 m thick.


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C.16 Advantages and Disadvantages of Constructed Wetlands

The use of CWs for treating or polishing wastewaters has a number of advantages, including that they:

Provide effective and reliable wastewater treatment

Are relatively inexpensive to adapt or even construct

Are relatively economical to operate and have low labour requirements

Are easy to maintain and have low energy requirements

Are able to accept varying quantities and concentrations of pollutants

Are relatively tolerant of fluctuating hydrologic conditions

Provide various indirect aesthetic benefits (e.g., habitat, green space, recreation)

The use of CWs for wastewater treatment is not a panacea; there are disadvantages to their use as well. These include that constructed wetlands:

Require large land areas

Are ecologically and hydrologically complex

Can lead to pest problems (e.g., mosquitoes in pond and FWS ones)

May not prove practical in some situations where local conditions (topography, drainage, soils, etc.) are not suitable

May require some time before optimum efficiency is achieved

Do not have many years of experience to draw on

Maybe unfamiliar to regulatory authorities who may not have precedents

Many early ones were misdesigned, leading to erroneous negative perceptions

May operate at lower efficiencies during winter Constructed wetland technology has evolved rapidly and ecological engineers are now able to design wetland and other natural wastewater treatment systems with as much confidence as to their operability and pollutant removal levels as with comparable conventional (mechanical) wastewater treatment systems. There are now constructed wetland systems operating in all provinces and territories of Canada from the mouth of the MacKenzie River in the Arctic to southern Ontario.

APPENDIX D ENGINEERED WETLANDS


D-2

D.1 Engineered Wetlands

The concept now known as Engineered Wetlands was developed in the late 1990s by an affiliate of engineering consultant, Conestoga-Rovers & Associates (CRA), called Soil Enrichment Systems Inc. (SESI), in a partially NRC IRAP-funded R&D project known as BioReactor Engineered Wetland (BREW). The Project also involved as participants universities (particularly the University of Waterloo [UoW] and the University of Guelph [UoG]), government agencies (the Ontario Ministry of the Environment, Environment Canada, and the then Municipality of Metropolitan Toronto), several engineering consultants (e.g., CRA, Altech Technolgies, Jacques Whitford), and other firms (e.g., Dofasco Steel) (Higgins, 1997, IRAP, 1999). The purpose of the BREW Project was to advance constructed treatment technology to allow CWs to provide enhanced secondary wastewater treatment year round, especially for otherwise difficult to handle wastewaters such as industrial process waters and landfill leachates. The BREW Project involved bench-, pilot- and demonstration-scale R&D using sub-surface flow wetlands. It showed that wastewater treatment of municipal sewage and landfill leachates in one m2 indoor pilot-scale HSSF EW test cells gave much the same kinetic results as testing in 25 m2 outdoor HSSF wetland cells, without the attendant environmental “noise” found with the latter. The BREW Project showed that roughly the same contaminant removal rate constants were obtained at both pilot and demonstration scales, indicating that the smaller, more controllable indoor pilot unit testing could be used in future treatability testing. Accordingly, results with smaller, pilot EW equipment could be scaled up to define design criteria for full-scale EW facilities. The BREW Project particularly addressed one major limitation of constructed wetlands, their relatively modest (30 – 60%) removals of the nutrients, particularly nitrogen and phosphorus. The BREW Project involved R&D on two aspects: placing aeration tubing under the gravel substrates of HSSF wetlands (see below), and replacing some or all of a SSF wetland’s gravel substrate with steel slag (this latter aspect being suggested by project participant, UoW, which was patenting the concept of phosphorus removal from wastewaters using slags under what would be called the Phosphex™ technology (Blowes et al., 1996). The EW concept quickly grew and evolved and now EWs can be described as advanced, semi-passive kinds of CWs which provide vastly superior wastewater treatment in relatively smaller areas, regardless of ambient air and water temperatures. Indeed, Constructed Wetlands now may be described as “engineered” if they involve one or more of the following aspects:

DESIGN MODIFICATIONS

Aeration

Engineered Substrates

System Ancillaries

PROCESS ADDITIONS/MODIFICATIONS

Energy

Chemicals

Dilution


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VEGETATION MODIFICATION

Stress-Resistant Species

Harvesting for Nutrients Removal

Phytoremediating Plants

ADVANCED SYSTEMS OPERATIONS

Stream Control

Recycle

Computerized Operation An Engineered Wetland’s design may be modified in several ways to enhance contaminants removal (Higgins, 2000). Adding air is one way to create an Engineered Wetland. The removal of many pollutants in a treatment wetland is dependent on microbially-mediated aerobic transformations such as ammonia nitrification. As was mentioned above, most of the needed oxygen for such reactions is supplied by wetland plants which “pump” air to microbes in their root zones. This limits the degree of oxidation reactions such as nitrification which can occur. For example, ammonia removals of from 30 to 60% are typical with ordinary (i.e., non-engineered) Constructed Wetlands. Oxygen availability also limits the thickness of SSF CW substrates to the maximum that roots can penetrate, (0.4 to 0.8m thick) and hence also reduces the potential for passive heat retention since thicker substrates allow better heat retention. One way to overcome this limitation is to add air to the wetland cells. This may be accomplished by placing mechanical aerators in bays or open areas, by operating in a fill & drain mode (see Section 6.3 below), or by using submerged perforated or diffuser piping through which air is introduced into the water under the substrates in SSF CW cells (Davies & Hart, 1990). By improving aeration, nitrification rates can be increased to over 99%+. And because the conversion of ammonia is often rate limiting in a wetland, adding air can sometimes dramatically reduce size (and hence the capital cost). In general, an aerated EW system treating municipal wastewater will have about half the cost of an equivalent mechanical wastewater treatment plant and 20 – 50% of the O&M costs. Aerated Wetlands are discussed in more detail in Appendix D.4 below. Stantec associate firm, NaturallyWallace Consulting (NWC) holds patents for this latter technology now known as Forced Bed Aeration™ (Wallace, 1998, 2000), and Stantec has rights for its use. As was discussed above, Sub-Surface Flow CWs pass the wastewater they are treating through a bed of porous medium of high hydraulic conductivity such as gravel. Another way by which such wetlands can be “engineered” is by replacing all or part of the gravel with a suitable engineered substrate capable of chemically adsorbing, precipitating and/or causing the volatilization of pollutants from the wastewater. By this means, the removal levels of certain contaminants (e.g., phosphates, arsenates), which can be relatively low in ordinary constructed wetlands, can be increased to 99% or more in engineered ones. The Phosphex™ technology is one example of this method of creating an EW.


D-4

Energy can be added to EWs (or other EW System processes, see below) to enhance performance. For example, many industries and other kinds of businesses which are sources of wastewaters requiring treatment have to manage, dispose of or otherwise handle large volumes of cooling water containing significant amounts of low-grade heat. Some of the main, size-dictating reactions occurring in treatment wetlands are highly temperature-sensitive, and this ordinarily would require design for the coldest conditions. This would result in wetland systems which were overly large (and expensive) and which were over-designed for operating conditions during most of the year. Energy addition, either by mixing in or heat exchanging with relatively warm cooling water, or by using cooling coils in primary EW cells, can greatly reduce the size of a wetland system. Such low grade heat can be used to keep wastewaters requiring treatment warmer than they would otherwise be, allowing enhanced treatment. In addition to adding energy, another way to engineer a treatment wetland system is modify it so that heat is retained. Microbially-mediated wetland processes (e.g., nitrification, de-nitrification) slow as wastewater temperatures drop, and may become so reduced at the coldest temperatures encountered (i.e., in winter) that the wetland will have to be very, very large to achieve desired effluent pollutant concentrations. However, many wastewaters (e.g., landfill leachates, municipal sewage) are naturally warm when generated and if the heat loss from them can be reduced, contaminant removal processes can be carried out at higher temperatures, requiring corresponding smaller wetlands. Sub-Surface Flow Wetlands retain heat much better than do other kinds, and their surfaces can be insulated with layers of mulch to even further retain heat. Pond Wetlands and lagoon cells in EWs can be fitted with insulated floating covers to retain heat. By using such process modifications, dramatically smaller EW Systems can be used. Another major way that EWs may differ from ordinary CWs is the practice with them of adding things to the process. Additions need not be limited to energy. Chemicals can be added as well. For example, a carbon-rich wastewater stream from another source can be added to a very low BOD, high nitrate stormwater to allow de-nitrification to occur, or alum can be added to a pond wetland cell or sedimentation pond cell to precipitate phosphorus, to name just two. In addition, the pH of a wastewater stream in an EW may be adjusted by adding acid or caustic to enhance certain removals and/or reduce toxicity. Similarity, in some cases dilute streams may be added as well (e.g., stormwater streams added to process streams being treated in an Engineered Wetland). Another way by which Constructed Wetlands may be “engineered” is by manipulating their vegetation. Often the wastewaters being treated in a CW contain contaminants or have conditions such that they will negatively affect the plants used, stressing or killing them. Wastewaters with excessively high or low pHs, or ones containing toxic pollutants or salt can be very hard on the common types of CW vegetation. However, wetland plants can be selected that are more stress-resistant, better allowing their use under such conditions. All emergent wetland macrophytes provide some level of phytoremediation, be it only adsorption on surfaces of their rhizomes (sub-surface root systems). With Engineered Wetlands, the possibility exists of enhancing this, and/or of even selecting wetland plants that have phytoremediating properties which allow them to take up and metabolize, sequester, and/or otherwise remove heavy organics, inorganics and heavy metals from wastewaters passing through their root systems.


D-5

Although it is well known that, at certain times of the year, wetland plants can take up part of a wastewater’s influent nitrogen, and phosphorus, the harvesting of vegetation from constructed wetlands to remove these contaminants is usually impractical and/or uneconomic and they are cycled back into the wetland as detritus. Harvesting is not normally carried out. However, EWs will often be used in special situations which may prove exceptions to this rule. With them, plant harvesting and disposal may be practiced. In addition, the “dry” surfaces of Engineered SSF Wetlands present an opportunity for harvesting equipment access much more easily than with Pond and FWS CWs. Still another way to engineer a CW is to operate it in an advanced manner. In engineered wetland systems, wastewater feed rates to the wetland cells may be monitored and controlled to maximize performance (e.g., lower feed rates and hence longer retention times may be used in colder weather to compensate for temperature effects). Another way which will enhance microbially-mediated aerobic reactions such as ammonia nitrification in a SSF CW is to periodically turn off the feed to all or some of the system’s wetland cells for short intervals, thereby allowing the water levels in them to drop (Fill & Drain operation). This pulls air into the substrates during the “off” cycle and such batch loading can increase the removal of those contaminants whose removals in a wetland depend on aerobic conditions. Engineered Wetland have to facilitate many contaminant removal reactions and some of them require conditions (pH, wastewater carbon content, alkalinity, aerobic conditions, anaerobic conditions) which may be present in one part of a wetland system but deficient elsewhere where they may be needed. In some cases, such limitations can be overcome by using multiple cells in a train and/or by recycling back part of a cell’s effluent stream to earlier in the system (i.e., pumping back part of a partially-treated one from downstream cells). An example where recycling might be considered is the de-nitrification of nitrates. This microbially-mediated reaction requires anaerobic conditions which may only occur after nitrates are created from ammonia in more aerobic, upstream cells which may also remove most of the carbon (i.e., BOD) which is required for the later de-nitrification reaction. Recycling some of nitrate-rich effluent to BOD-rich influent can solve this carbon deficiency problem.

D.2 EW Systems

Wastewaters such as sewage may be treated either in passive or semi-passive natural treatment systems (e.g., wetlands) or active conventional (mechanical) treatment systems The latter include Wastewater treatment plants (WWTPs) such as those based on the activated sludge process, on diverse kinds of membrane-based systems, and on many others. WWTPs, whether natural ones such as those based on natural systems or fossil fuel- based mechanical ones, involve an integrated treatment approach involving pre-treatment (e.g., settling and/or screening to remove large objects from a wastewater), primary treatment (1° treatment, physical and/or chemical treatment largely to remove solids suspended in the wastewater), secondary treatment (2° treatment, involving biological treatment such as activated sludge, largely to remove dissolved organics and some nutrients from the wastewater), and tertiary treatment (3° treatment or polishing, which may involve further physical, chemical and/or biological treatment, especially to remove nutrients and other dissolved species to high levels).


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Where wastewaters are also microbially-contaminated (e.g., sewage), WWT systems often involve final treatment by chlorine or ultra-violet (UV) disinfection. EWs are often used as the secondary (biological) treatment step of more comprehensive wastewater treatment systems referred to as Engineered Wetland Systems. These systems may incorporate just the secondary (EW) treatment step, or may include primary treatment (physical and/or chemical unit operations such as coagulation/ precipitation) and/or tertiary treatment steps (e.g., carbon filtration, phosphorus sorption) as well as pre-treatment (e.g., screening) and disinfection steps. An example of the former is an EW System involving an anaerobic EW cell, a Biochemical Reactor (BCR, see Appendix D.7 below), followed by a Forced Bed Aeration™ cell used to treat stormwater runoff from Hydro Quebec’s electrical utility pole storage yard at Laval, QC that becomes contaminated with the wood preservatives used to protect the wooden poles stored there from degradation (pentachlorophenol and copper chrome arsenate). An example of the latter is the EW-based wetland treatment System at Buffalo Niagara International Airport that treats glycol-contaminated stormwater there. It involves oil/grit separation as a primary treatment step and four Forced Bed Aeration™ EW cells, each as large as a football field containing gravel substrate 1.5 m thick as the secondary step. In fact, EW cells are rarely used alone and usually are part of a more comprehensive wastewater treatment system that may contain Pond Cells, FWS Cells, ordinary SSF CW cells as well as the ancillaries such as sedimentation ponds, lagoons or other natural treatment processes (e.g., overland flow systems). When a wetland system is engineered, these system ancillaries can be more complex, involving high performance aerated lagoons (HPALs) located upstream of EW cells, floating aquatic plant WWT cells, land WWT units, bioreactors, limestone drains and many other things. While EW Systems can and do usually involve some mechanical equipment (e.g., pumps, blowers, chemical injection facilities) and unit operations (e.g., sedimentation ponds, sand filters, aerated vessels), there is a preference with them to involve other kinds of natural wastewater treatment unit operations in their primary and secondary treatment steps. These may include ordinary CW cells, facultative and aerated lagoons, overland flow systems, floating aquatic plant treatment cells, bioreactors, ponds and many others. Examples of recalcitrant (i.e., difficult-to-treat) wastewaters that EW Systems can successfully treat include leachates from landfills, landfarms, and industrial waste tips; overflow from combined sewer systems (CSOs); acid rock drainage (ARD) from mines; industrial process waters (e.g., the high BOD, high phosphate streams from food processing plants); sludges, runoff and washwaters from intensive farming/livestock raising operations; and contaminated groundwater and surface water flowing through sites requiring remediation. Stantec has pilot-scale EW test facilities at two colleges in Ontario, at which treatability testing may be carried out to both demonstrate the ability of the EW ecotechnologies to treat new wastewaters but also to determine the kinetic and other scale up parameters needed to design subsequent full-scale EW Systems.


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The operating costs for an EW System will usually be higher than those for an ordinary CW System (but still very much less than those of a mechanical WWT plant), and an EW system will only be economic vs an ordinary CW where its special qualities (e.g., lower capital costs, the ability to handle otherwise hard-to-treat - i.e., recalcitrant - wastewaters better, etc.) more than compensates.

D.3 Engineered Stormwater Wetlands (ESWs)

Ordinary Stormwater Wetlands only remove limited amounts of suspended solids, and little dissolved contaminants. However, increasing environmental stresses on many receiving waters such as lakes and rivers has regulators and the public expressing growing concern on their contamination from conventional stormwater management systems. Because of this, Stantec has extended the EW concept from Treatment Wetlands to Stormwater Wetlands, by creating a new class of EW System called an Engineered Stormwater Wetland (ESW). ESWs are multi-cell stormwater treatment systems involving at least one EW cell. Typically, ordinary Stormwater Wetlands (including wet and dry ponds) have large, usually wet, inlet forebay areas (plunge pools) at their entrances in which grit settles out, oil & grease are filtered out, and some suspended solids are removed. However, these forebay areas are usually relatively large, only remove limited amounts and kinds of contaminants, and their sizes restrict options where available land supply is tight. Various companies have developed and offer for sale advanced oil/grit/sediment (OGS) removal vessels which not only more efficiently remove oil and grit, but also allow much higher removals of suspended solids (up to 70 - 80%) in vessels which are a fraction the size of the forebays they replace. Examples include Imbrium Inc.’s vortex-based Stormceptor OGS (Perry et al.) and Wincester Concrete’s lamella-type Watergate OGS (Higgins et al., 2010b). Such vessels can provide advanced primary treatment as part of an ESW, while at the same time eliminating (or at least greatly reducing the size of) a forebay. Following an OGS vessel, a SSF EW cell is used in an ESW to provide secondary treatment as part of an ESW. As stormwater flows are highly variable, the kinds of SSF EW cells used in an ESW have to have relatively high freeboards (headspaces above the EWs’ gravel surfaces below their berm tops). The SSF EW cell in an ESW operates in an HSSF mode for low stormwater flows from minor precipitation events. When larger stormwater events occur (e.g., 2 – 5 year storms), the EW basin fills up above its gravel surface and the water thereby collected in it then later percolates down into and through the EW’s substrate in a VSSF mode after the storm event is over. Thus, the EW cell of an ESW is a special kind of combined HSSF/VSSF wetland. The final cell of an ESW can be a simple FWS or Pond Wetland and this provides final polishing of the stormwater before its discharge. The entire ESW’s basins can be designed to flood to accommodate even larger storms (e.g., 50- and 100-year storms). A demonstration ESW has been designed by Stantec to upgrade a stormwater dry pond in the Town of Aurora (Higgins et al., 2010b). Stantec soon will be proceeding soon with the design of a second ESW system, one planned to upgrade a stormwater wet pond in the Town of Uxbridge, ON.


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D.4 Aerated SSF Wetlands

For the engineered version of the aerobic wetland technology (the Forced Bed Aeration™ Aerated SSF EWs mentioned above), operation is carried out in a fully saturated mode, with air supplied by a blower, and an aeration system placed under the gravel. The Aerated SSF EW is then operated either with downflowing wastewater applied at or just below the substrate surface moving countercurrent to uprising air bubbles (i.e., VSSF) or with the wastewater flowing horizontally (i.e., HSSF) through wetland beds in which the air bubbles rise. The result is greatly enhanced microbially-mediated oxidation. The following tables summarize the results of the BREW Project pilot-scale experiments for four major pollutants (suspended solids, BOD, ammonia and total phosphorus) in two trains of the indoor EW test unit used for the BREW Project in the late 1990s (IRAP, 1999), where one train used quartz gravel as the substrate for an aerated EW cell and the other used a 50/50 gravel/BOF slag mixture in an EW cell that was also aerated, comparing the results with those for un-aerated HSSF CWs available in the literature (Reed et al., 1995, Kadlec & Knight, 1996). Table D.1 shows average results for suspended solids.

Table D-1: BREW Project Pilot Unit Results – Suspended Solids (Septic Overflow Feed)

Gravel Gravel/Slag Literature

Average Influent Concentration (mg TSS/L) 64 64

Average Effluent Concentration (mg TSS/L) 1 1.5

Removal (%) 99 97 70 - 85

Indicated SS PFR Rate Constant kv (yr-1) 912 314

As may be seen from Table D.1, the BREW Project results indicate that excellent removals of suspended solids were obtained. (Current EW design – see below - uses the tanks-in-series [TIS] reaction kinetic model but at the time of the BREW Project, literature data was only available expressed according to the plug flow reactor [PFR] model, so BREW results were also presented under that model.) Table D.2 presents the results of the BREW testing for BOD.

Table D-2: BREW Project Pilot Unit Results – BOD5 (Septic Overflow Feed)


Average Influent Concentration (mg BOD/L) 149 153

Average Effluent Concentration (mg BOD/L) 6 3

Removal (%) 96 98 70 - 85

Indicated BOD PFR Rate Constant kv (yr-1) 919 669 403*

* Value from Reed et al. (1995). Kadlec & Knight (1996) give the equivalent of 789 yr-1

.


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As with suspended solids, excellent BOD removals were obtained during the test runs, with results for the ordinary (gravel substrate) EW cell being better than BOD removal rate constants reported in the literature. The results showed that for septic tank overflow, at least some of the components of the BOD appeared to be susceptible to increased degradation when aeration was used. (Organic matter in septic plant overflow is relatively easy to degrade in either a CW or an aerated EW, so it is not unexpected that the BREW results only showed modest improvements for BOD removal. Later testing with less labile feedstocks [Jacques Whitford, 2005a, 2005b] showed much better improvements.) The following table presents comparable BREW results for ammonia.

Table D-3: BREW Project Pilot Unit Results - NH3-N (Septic Overflow Feed)


Average Influent Concentration (mg NH3/L) 73 61

Average Effluent Concentration (mg NH3/L) 1 3.6

Removal (%) 99 96 25 – 35

Indicated NH3-N PFR Rate Constant kv (yr-1) 1529 261 150*

* Value from Reed et al. (1995).

Ammonia degradation rates were very high in the train containing aerated EW cell with gravel substrate, more than an order of magnitude higher than might be indicated from literature data for HSSF CWs where no aeration was involved. Lower (but still higher than literature values) rate constants were calculated for the train with an aerated EW cell which had the gravel/BOF slag mixture as its substrate, perhaps due to the difficulty experienced in maintaining a biofilm in the highly alkaline (pH>10) environment of the cell (but a biofilm did form; the cells for the BREW project had windows in their sides). The following table presents the BREW Project pilot unit results for phosphorus removal.

Table D-4: BREW Project Pilot Unit Results – Total Phosphorus

(Septic Overflow Feed)


Average Influent Concentration (mg TP/L) 19 20

Average Effluent Concentration (mg TP/L) 7 0.5

Removal (%) 63 98 20 – 60

Indicated TP PFR Rate Constant kv (yr-1) 98 443 53*

* Value from Kadlec & Knight (1996).

As may be seen, the train with the gravel cell showed a result roughly equivalent to that which might be expected in ordinary un-aerated CWs from literature values (and probably indicated simple adsorption of some ortho-phosphate on the quartz particles), but the much higher rate were found in the train containing the HSSF cell with the BOF slag indicated that chemical sorption was occurring with the slag as well (and perhaps also some precipitation due to interstitial lime, although the BOF slag for the BREW Project was well weathered and washed before use – see Appendix E.3).


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The following table summarizes typical results for treating raw landfill leachate in the BREW pilot unit where the feedstock, instead of being septic tank overflow, was raw leachate from the Keele Valley Landfill north of Toronto. (Gravel was the substrate.) For this case, because of the strength of the leachate, part of EW cell’s treated effluent was recycled to dilute incoming leachate. The recycle rate was 1.5:1.

Table D-5: BREW Project Pilot Unit Results (Landfill Leachate Feed)

Inlet Concentration Outlet Concentration Rate Constant

(mg/L) (mg/L) (yr-1)

BOD 4,500 6 531

NH3 713 76 170

TP 13 0.1 339

As may be seem, the BREW Project pilot unit was very successful in reducing to very low levels the BOD in the leachate (>11,000 mg/L in this case) although the feed to the aerated EW cell still had a very high 4,500 mg BOD/L in it even after dilution with 1.5 times as much recycle from the effluent. Normally, in an HSSF CW, a wastewater BOD of 4,500 mg/L would be expected to kill any wetland vegetation that it came in contact with. However, during the BREW testing, the plants (reeds) suffered no noticeable ill effects during the experiment, or even during subsequent ones where raw leachate was introduced without recycle dilution. This was probably due to the fact that the extremely eutrophic conditions which would have normally resulted were such a wastewater introduced into an ordinary constructed wetland were prevented by the aeration. The BREW Project results demonstrated that the concept of engineered wetlands was correct, and the project assisted in the development of the Forced Bed Aeration™ and Phosphex™ technologies. It also showed that unless an EW cell containing an engineered substrate such as steel slag was involved, only limited phosphorus could be expected. Continuous flow reactor bench scale comparisons (Matthys et al., 2000) of a conventional VSSF operation (i.e., simulating an ordinary CW), periodic flooding and drawdown VSSF operation (i.e., simulating a Fill & Drain Wetland, see Appendix D.5, below) and aerated VSSF operation (i.e., simulating an aerated EW) have shown that while the Fill & Drain EW performed better than the ordinary CW, the aerated EW greatly outperformed the other two in terms of organics and ammonia nitrogen removals. In addition, the rooting patterns were significantly affected by the supply of oxygen and, for the system simulating the aerated EW, cattail roots spread vertically (vs. horizontally in the other two systems) much deeper into the substrate at a much quicker rate. It has since been shown in larger scale Aerated VSSF EW cells that the roots of wetland plants in them extend very much further into the substrates (up to a metre or more) (Jacques Whitford, 2005a). Since then, the vast superiority of this Aerated SSF EW (Forced Bed Aeration™) technology in removing oxidizable contaminants (e.g., ammonia, most organics) from wastewaters of all sorts has been demonstrated and proven in a variety of other pilot-, demonstration- and full-scale projects. It has been successfully used to treat all sorts of


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municipal, industrial, and agricultural wastewaters summer and winter. Forced Bed Aeration™ EWs are much smaller in surface area (one-fifth to one-tenth the area of an ordinary CW); very much more efficient in pollutant removals (almost complete removals of organics and ammonia are possible); able to operate successfully and at high efficiencies whatever the water and ambient air temperatures are (down to 0.5°C water temperature); and can treat very high flow rates of water (up to thousands of m3/d). Forced Bed Aeration™ EWs are effective both when wastewaters containing very high BOD COD, ammonia and/or other pollutant levels are being treated, and, conversely, when ones with very low BOD and/or nutrient levels are being treated but extremely low effluent levels are needed. EWs can treat wastewaters with high or low pHs; wastewaters with highly intermittent flows and/or pollutant levels: salt-contaminated wastewaters; and ones saturated with certain species (Higgins et al., 2010 a, 2010b, 2010c, Mattes et al., 2010) Pollutant removal rates in aerated SSF EWs are much higher than those found with ordinary CWs (often ten times as much or more for certain contaminants) and aerated EW systems require much less energy for aeration than do equivalent mechanical, activated sludge-based WWTPs (about 1/10 as much). Aerated EW systems often cost less than half that of a conventional mechanical WWTP to build (if lagoon upgrading is involved), and have very much lower O&M and Life Cycle costs than mechanical WWT plants. Extensive tracer testing has shown that Aerated SSF EWs behave like completely stirred reactors (CSRs) and, based on the results of treatability tests, larger scale facilities can be sized using a CSR design model (or the slightly more conservative two or three Tanks-In-Series [2TIS or 3TIS] design models). In many mechanical WWTPs, dealing with excess Waste Activated Sludge (WAS or biosolids, living and dead bacteria from the secondary treatment aeration tanks of the activated sludge unit) is a major part of operational complexity. These excess biosolids, the organic sludge byproduct of the treatment process, require conditioning, stabilizing, de-watering and disposal. Indeed, such biosolids management can be responsible for up to 2/3 of a mechanical WWTP’s energy costs. Aerated SSF EWs can be designed so that the rate of formation of organic sludge is equal to or less than the rate that this sludge is removed by rhizodegradation reactions. This unique ability NOT to generate organic sludge vastly simplifies their operations and costs. (However, EW Systems may nevertheless produce primary treatment sludges and backwashes from tertiary treatment systems that require further management.) Over 70 smaller aerated HSSF and VSSF EWs are now in operation in a number of northern U.S. locations, as well as several large ones. Four very large aerated VSSF EW Systems have been designed by Stantec: one treating BTEX-contaminated groundwater at a former BP refinery site in Caspar WY (6,000 m3/d); one treating 5,500 m3/d from the Town of Alexandria in eastern Ontario; an even larger industrial EW system (17,000 m3/d) treating cyanide- and ammonia-contaminated tailings pond reclaim water at a gold mine in Suriname in South America; and a large system operating at Buffalo Niagara International Airport (BNIA) This latter system, which is successfully treating glycol-contaminated stormwater runoff and spent glycol from cold weather aircraft de-icing activities, involves four very large Forced Bed Aeration™ cells, each as large as a football field and containing gravel substrate five feet thick (Higgins et


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al., 2010a). The EW System, which is located alongside the main runway at BNIA and looks like four grassy fields, is capable of treating up to 1.2 MM USGPD of glycol-contaminated water containing up to 10,000 #/d of BOD, even in the coldest weather, and treats the BOD-equivalent of a city of 50,000 people. Recently, for this project’s design Stantec (along with its client, the Niagara Frontier Transportation Authority, its civil engineering sub-consultant, Urban Engineers of NY, and its process sub-consultant, NaturallyWallace) was awarded the Diamond Award in the Environmental Category by the NY branch of the American Council of Engineering Companies (ACEC) and a very prestigious Honor Award by the US National ACEC. The project has also won awards from the American Public Water Works Association and the Airport Council International (ACI).

D.5 Fill & Drain Wetlands

Fill & Drain SSF Wetlands, also variously referred to as reciprocating bed, tidal flow, pulse flow and cyclic wetlands, are kinds of high freeboard, downflow SSF Engineered Wetlands where the substrate beds (usually gravel) are periodically flooded then drained, resulting in partially unsaturated beds. Applied batches of wastewater percolate down through the substrate, and air is drawn into the bed as the water level drops. This allows aerobic reactions such as nitrification to occur at rates up to double that possible in an ordinary SSF CW with removal rates above 95% (vs 40 - 60% in ordinary SSF CWs) (Matthys et al., 2000). During the flood stage, providing sufficient alkalinity is present, NH4

+ ions adsorb to negatively-charged biofilm located between the substrate particles, and aerobic microbes in the biofilm oxidize them to nitrate. During a subsequent flood stage these NO3

- ions are desorbed back into the bulk wastewater where de-nitrification will occur if there is sufficient carbon present. Enhanced (>90%) removals of several other contaminants (BOD, TSS, pathogens) also occur in Fill & Drain SSF EWs.

D.6 Anaerobic SSF Wetlands

The Anaerobic Wetland technology involves contacting a wastewater containing dissolved metals/metalloids and other reducible contaminants (e.g., nitrates, sulphates, some organics) in a wetland with a bioavailable carbonaceous material that is added and/or forms part of its soil, sediment or solid substrate bed. The carbonaceous material (reactive medium) may be added in a liquid form (e.g., as part of solutions containing alcohols, aldehydes and/or other organics) along with the

wastewater being treated. Alternatively (and more usually), the reactive medium may be in a solid form (e.g., manure, wood chips, compost, biosolids) forming part of a substrate matrix (wetland bed). Anaerobic Wetland beds with solid carbonaceous material often include mixtures of, and/or layers of substrate support material such as sand, gravel or rock to improve permeability, and layers of limestone to adjust pH. The substrate beds in Anaerobic Wetlands create a habitat for facultative and anaerobic (including fermentative) microbial populations (i.e., acid-producing bacteria [APB]), iron-reducing bacteria (IRB), iron-oxidizing bacteria (IOB), and sulphate-reducing bacteria, SRB).


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APB metabolize complex and simple organics in the reactive medium (or media) by a variety of anaerobic fermentation and respiration reactions, break downing organic contaminants to produce compounds such as ethanol and acetate which can be further metabolized by SRB. SRB contribute to alkalinity as follows: (D.1)

where CH2O represents the carbonaceous material. Below pH 8, the sulphide is present as S2-. The hydrogen sulphide ions react with many dissolved metals and metalloids in wastewater passing through the beds to precipitate them in insoluble forms. Indeed, one of the most important roles of Anaerobic Wetlands is in the biological removal of dissolved metals and metalloids as insoluble, precipitated sulphides as follows (illustrated for divalent cations): (D.2)

where Me represents a typical dissolved divalent metal cation such lead or zinc. These sulphides are highly insoluble and are resistant to oxidation and re-mobilization should an Anaerobic Wetland’s bed ever be exposed to oxic conditions. Some bivalent meals which do not form sulphides may form hydroxides instead but these are less insoluble and may be subject to oxidation and re-mobilization if the Anaerobic Wetland’s bed is exposed to oxic conditions. (There are, however, ways to deal with this problem.) It is noted that two moles of alkalinity and one mol of acidity are the result of the reactions illustrated above, so the combined action of the SRB is to raise alkalinity and buffer the solution. The following table shows the theoretical solubilities of bivalent cation sulphides and hydroxides in pure water (Palmer et al., 1988).

Table D-6: Theoretical Solubilities of Bivalent Cation Sulphides and Hydroxides (mg/L)

Sulphide Hydroxide

Cadmium 6.7 x 10-10 2.3 x 10-5

Chromium No precipitate 8.4 x 10-4

Cobalt 1.0 x 10-8 2.2 x 10-1

Copper 5.8 x 10-18 2.2 x 10-2

Iron 3.4 x 10-5 8.9 x 10-1

Lead 3.8 x 10-9 2.1

Manganese 2.1 x 10-3 1.2

Mercury 9.0 x 10-20 3.9 x 10-4

Nickel 6.9 x 10-8 0.9 x 10-3


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Silver 7.4 x 10-12 13.3

Tin 3.8 x 10-8 1.1 x 10-4

Zinc 2.3 x 10-7 1.1

Metal removal processes in Anaerobic Wetlands (and BCRs) are not limited to those involving bivalent cations. Dissolved selenium in a wastewater passing through an Anaerobic Wetlands may be removed by reducing it to elemental selenium. Aluminum, if present in a wastewater in any significant quantities (i.e., above a few mg/L), will form gelatinous aluminum hydroxides that can cause plugging in a SSF wetland if the water’s pH is raised under aerobic conditions. However, aluminum can be readily removed as a precipitate in an Anaerobic Wetland without plugging. A potential mechanism (Thomas & Romanek, 2002) may involve the production of alunite: (D.3)

For metals which form oxyanions in water instead of cations (e.g., arsenic), slightly different microbially-mediated processes are involved but these also can lead to the formation of insoluble sulphides, as shown for arsenite removal under some conditions as outlined in the following equations. (D.4) (D.5) As may be seen, unlike the situation with the removal of bivalent cations (e.g., Cu, Zn) in an Anaerobic Wetland where one mol of sulphate reduces one mol of metal, for arsenic three mols of sulphate are required to reduce two mols of it. Additionally, in Anaerobic Wetlands (and BCRs) chemically- and microbially-mediated iron reduction and oxidation reactions form compounds which complex with many contaminants, removing them from the wastewater as precipitates in the bed. Other anaerobic processes (e.g., de-nitrification, the degradation of many chlorinated organics) also will occur in the reducing conditions of the bed. Dissolved oxygen levels in the substrate of an Anaerobic Wetland are low (<1 mg/L) and redox levels (ORP) is negative (< -200 mV).

D.7 Anaerobic Biochemical Reactors

The ultimate, Engineered Wetland version of an Anaerobic Wetland is called an Anaerobic Biochemical Reactor (BCR, formerly referred to as an anerobic bioreactor, ABR). (If the main reaction is only de-nitrification, the system may be referred to as an anoxic bioreactor instead.) BCRs are specialty units for carrying out sulphate reduction and other anoxic reactions. BCRs are made up from beds of the reactive media (carbonaceous material) and support substrates such as gravel, sand and/or limestone. These in-ground, semi-passive bioreactors can be operated as stand alone, multi-layer units, or they can be expressed as one or several VSSF EW cells in series. Wastewater to a BCR may be applied at the surface to move downflow, or may flow up from the bottom of the substrate bed (Neculita et al., 2007, Mattes et al., 2010).


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Microbiology in BCRs is similar to that in Anaerobic SSF Wetlands. As may be seen from Equations D.1, D.3 and D.5, an adequate supply of sulphate is necessary in the wastewater being treated for the reactions to work. The carbon source can be any type of carbonaceous material (e.g., sawdust, wood, biosolids, manure) submerged in the bioreactor’s water, the decaying roots/detritus of the wetland plants, an added soluble carbon-based liquid material (e.g., methanol), or a layer/cell fully or partially filled with microbially-available carbonaceous mat. The surfaces of BCR EW cells are usually un-vegetated, and BCRs are often buried or designed to have deep water (1 - 2 m) on their surfaces to maintain anaerobic conditions. As most BCRs (as well as Anaerobic SSF EWs and SAPSs) leach various materials (e.g., suspended solids, ammonia, nitrates, BOD) from their substrates, it is common practice by Stantec with an EW System to include one or more Aerobic Wetland cells (e.g., usually Aerated VSSF EW ones) downstream of the BCR cell(s) to remove these pollutants. Wastewater containing dissolved metal(loid)s can be fed into BCRs using distributors buried in or below one of the substrate layers or, in warmer climes for downflow operation, by surface distributors or sprayers. In colder climates, buried inlet and outlet distributors can be used to direct flow up through the cells, and, as was mentioned, the unit buried or a deep layer of water placed over the cells for carbonaceous material such as municipal compost or biosolids. Stantec is involved in designing a BCR-based EW demonstration system (500 m3/d) which also will include an Aerated VSSF EW at a gold mine in Northern Ontario, as well as several bench- and pilot-scale BCR-based EW projects for the removals of metals such as Cu, Sb, and Cr. The state-of-the art BCR-based EW technology used by Stantec is that developed by Nature Works Remediation Inc. (Nature Works), a Stantec associate firm. Nature Works now operates a field-scale BCR-based EW system at Teck’s lead zinc smelter in Trail BC. This facility, which has operated summer and winter for the past six years (and during summers for several years before that), includes two BCR cells followed by three HSSF CW cells and a Pond Wetland cell. It is designed to treat highly metal-contaminated landfill leachate. This EW system removes dissolved zinc (up to thousands of mg/L), arsenic (up to a thousand mg/L) and cadmium (up to a hundred mg/L) reducing their concentrations to a few (Zn) to much less than one mg/L (As, Cd). Sulphate ions present at the input at mean concentrations of up to 1,600 ppm are reduced in it to about 750 ppm. Originally designed as a field-scale system to treat 20 - 25% of the landfill leachate, the Teck EW System has proven to be robust enough to treat up to 125 m3/d, and is now considered by Teck to be a back-up treatment option to its metal refinery’s WWTP plant for the entire collection of landfill leachate (Mattes et al., 2010). BCRs can treat both ARD or NMD. With the former, either it is preferable to locate a SAPS cell upstream of the BCR to raise pH, or to incorporate a layer of limestone into the inlet side of the BCR bed.


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When designing a BCR cell for an EW System, it is important to ensure that several important requirements are met (Neculita et al., 2007). These are:

Near neutral pH

Available carbon from a suitable organic source

A solid matrix, (sand and/or gravel) onto which SRB can establishment micro-environments

An anaerobic (or at least anoxic) environment

A supply of sulphate in the water being treated sufficient that the SRB can outcompete methanogens for available carbon

A way to physically retain the metal sulphides that will be produced

There are a number of large pilot-, demonstration- and full-scale BCR-based dissolved metal treatment systems in operation in the USA and elsewhere, including ones at:

West Fork Missouri

July 14, Pennsylvania

Fran Mine, Pennsylvania

Golinsky Mine, California

Lutrell Repository, Montana

Lilly Orphan Boy

Surething

Fabius Coal Mine (WV)

Wheal Jane Mine (UK)

Haile Mine

Elizabeth Copper Mine

Peerless Jenny King Mine

Burleigh Tunnel

MSF Waste Rock

Forest Queen For example, the full-scale BCR-based EW system at West Fork on the Black River is designed to treat 1,200 USGPM of lead-contaminated minewater and consists of two BCRs (0.2 ha each), an aerobic rock filter (0.6 ha), an aerated pond (0.8 ha) and a polishing/settling pond (0.3 ha). It has been operating year round since 1996 and used sawdust, limestone, manure and hay in its 2 m thick BCR substrates. It reduces lead from about 0.6 mg/L in the influent minewater down to meet NPDES effluent criteria of 0.027 to 0.05 mg/L.

D.8 Wastewaters Treatable in EW Systems

Engineered Wetland Systems have been successfully used to treat all sorts of municipal, industrial, and agricultural wastewaters. They may find particular applicability where it is difficult to achieve really good pollutant removals using more conventional WWT technologies where some of the following conditions apply for the wastewater being treated: very high BOD, COD, ammonia and/or other pollutant levels; very low BOD and/or nutrient levels; high or low pH; very cold wastewaters; highly intermittent flows and/or pollutant levels: salinity; and


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saturation with certain species. Examples of such recalcitrant (i.e., difficult-to-treat) wastewaters that can be readily treated in EW Systems include leachates from landfills (Nivala, 2005), landfarms, and industrial waste tips; seepages from metal mine tailings ponds; acid rock drainage (ARD) from mine acid-generating tailing and waste rock piles; effluents from mine leach beds; certain industrial process waters (e.g., the high BOD, high phosphate streams from food processing plants); runoff and washwaters from intensive farming/livestock raising operations; contaminated runoff from northern airports carrying out glycol de-icing in cold weather; contaminated groundwater and surface water flowing through sites requiring remediation; and a variety of liquid sludges (e.g., the 0.5 - 2% solids) from the activated sludge units of conventional wastewater treatment plants. EWs can and have been used to treat a variety of municipal wastewaters including:

Municipal Sanitary Sewage

Septic Tank Overflow

Liquid Municipal Biosolids

Septage

Combined Sewer Overflow (CSO) Water

Municipal Landfill Leachates

Compost Facility Leachates

Municipal Stormwater One major opportunity for EW Systems is in the upgrading of lagoon-based WWT facilities (Higgins et al., 2010c). Many communities have been using such WWT facilities for long periods, but evolving stricter regulations and sludge build ups in the lagoons now dictate their upgrading. EW Systems are ideal for doing so, especially since the EW cells per se often can be located within the boundaries of an existing, decommissioned lagoon. With EW upgrades of lagoon-based WWT facilities, ones which had only been allowed seasonal discharge can be converted to continuous discharge and effluent quality vastly improved. For lagoon-based WWT facilities upgrades, EW systems will prove more economic to build than alternative mechanical WWTPs (about half the capital cost), be cheaper to operate (20 - 40% of the O&M costs), and are suitable for communities generating up to 10,000 m3/d of raw sewage. An example is an EW System for a lagoon upgrade is a system designed for the Town of Alexandria in eastern Ontario where an existing one-aerated lagoon, three-facultative lagoon system can no longer meet the discharge criteria of its Certificate of Approval (C of A). Stantec’s design for an EW System to upgrade the lagoon system is for a design flow rate of 5,500 m3/d of raw sewage, and involved installing an equalization pond (in an old lagoon) and inlet screening equipment; upgrading the poorly-performing surface aspirated aerated lagoon by converting it to a two-cell High Performance Aerated Lagoon (HPAL) with submerged coarse bubble aeration; installing alum precipitation equipment and a sedimentation pond; carrying out secondary treatment in three, parallel EW cells in an old lagoon; and disinfecting system effluent using UV. Sludge de-watering in four Biosolids Stabilization EW cells is also involved, and the regulator, the Ontario Ministry of the Environment (MOE) has approved an amendment to the site’s C of A for the EW System (Jacques Whitford, 2005b).


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While CWs can be used to treat a variety of agricultural wastewaters, Engineered Wetland Systems are even more suitable for doing so and can be designed to treat any of the following agricultural wastewaters:

Liquid Manures

Milkhouse Waters

Exercise Yard Runoff

Tile Drain Discharges

Feed Lot Runoff

Process Waters from Agribusiness Operations

Anaerobic Digester Effluent Engineered Wetland Systems have particular advantages in the treatment of a variety of industrial wastewaters including:

Process Waters

Cooling Waters

Product & Raw Material Pile Runoffs

Lagoon & Sludge Pit Materials

Landfarm Leachates

Ballast Waters

Commercial/Industrial Landfill Leachates

Industrial Facility Stormwaters A Stantec affiliate was responsible for a demonstration wetland pilot at General Motors’ Saginaw MI Metal Castings plant. The HSSF EW treats industrial wastewater and recycles it for use in a stream with waterfall and fish pond at the plant entrance. In addition to a long record of the treatment of minewaters in CWs, EW Systems can now be used to treat a variety of wastewaters and runoffs from mining & metallurgical facilities including:

Acid Rock Drainage (ARD)

Neutral Mine Drainage (NMD)

Leachates for Heap Leach Piles

Percolates through Tailings Dams

Mill Process Waters

Metal Refinery Process Waters

Sanitary Sewage at Minesites

Stormwater Runoff at Mine Sites Stantec designed an EW System for Rosebel Gold Mines in the Republic of Suriname in South America (Jacques Whitford, 2005a). The project involved proof-of-concept treatability testing in Canada and at the RGM site. The system designed involves an aerated lagoon (now in operation) and several trains of aerated downflow VSSF cells to remove ammonia, cyanide and other contaminants to very low levels.


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One of the commonest uses for Aerated SSF EWs are as the main treatment step in On-Site WWT (where they replace the leach bed of septic systems for single homes) and in larger De-Centralized WWT Systems for communities of a number of homes (and often other facilities) which, although connected to the EW by sewers, are not accessed by major trunk sewers to large central wastewater treatment plants. (The latter are often also called cluster systems.) EWs are ideal for De-Centralized WWT and may accept primary treated sewage from individual; septic tanks at each of a cluster’s homes and businesses, or may be part of an EW System which includes one or more Imhoff tanks (large-scale septic tanks) upstream of EW treatment cells. Treated water disposal from EW-based De-Centralized WWT systems may be infiltrated into local soils (if such are suitable and regulations permit) or disposed into receiving waters like the water from central WWTPs.

D.9 Design of EW Systems

Engineered Wetland Systems are designed in manners similar to other kinds of WWTPs. While the sizing (determining required surface area needed for a particular wastewater treatment situation) of ordinary CWs is often carried out using empirical correlations (e.g., selecting some pre-determined m2 of area per Pe or m3/d of wastewater), EWs are sized using reaction kinetics (Kadlec & Knight, 2006, Kadlec & Wallace, 2008). Generally, for Aerated HSSF or VSSF EWs, sizings are carried out using the TIS model assuming conservatively that the number of tanks in series (N) is 2. However, Anerobic EW cells (e.g., BCRs) may still be sized using the empirical relationships. In order to design an EW System, information is required on the flow rates of the wastewaters involved (base and peak rates); the contaminant loadings in the wastewater; the location, nature and condition of the receiving waters (or aquifer for soil infiltration disposal); expected target effluent quality; site considerations (space, soils, climate, geology), and any relevant economic considerations. Using the data assembled, mass and heat balances are carried out and the design proceeds in the manners outlined in the two aforementioned textbooks. For most EW Systems, influent wastewater flows are equalized in some manner and introduced into the system at some controlled rate. The design approach takes peak flows into account. (It is, however, noted that that EW systems have high turndown ratios and can operated successfully over ranges from a few percent of design flow rate to 150% for short periods with no adverse effects. EWs can even be “turned off”, i.e., left with no flow for months at a time with little effect,) The design & engineering of field scale EW Systems involves sophisticated chemical and civil engineering methods, and generally proceeds in stages from a preliminary Systems Analysis phase involving any Feasibility Studies and other analyses as well as any Treatability Testing through an initial design phase (Conceptual Design) to a Final Design phase before implementation. In some cases, especially for larger EW projects, the needs for client approvals, regulatory approvals, outside stakeholder buy-in aspects, and the ability to accommodate inevitable last minute design changes, dictate that the Final Design phase be considered as two stages in series, Preliminary Detailed Design and Final Detailed Design. The former involves the actual design & engineering of the proposed wetland system, while the latter involves finalization of the


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design, the preparation of approved construction drawings and specifications, and assistance the tendering of the project to a contractor or contractors who will implement its construction. In general Stantec envisages EW projects being divided into six phases as follows:

Phase 1 –Treatability Testing/ Feasibility Study Phase 2 – Conceptual Design Phase 3 – Final Design Phase 4 - Construction Monitoring and Oversight Phase 5 – Start Up and Commissioning Phase 6 – Operations & Maintenance

The cells of EW Systems are often lined with geomembrane liners (HDPE, PVC or bituminous) but in some cases, where soils or local sources are appropriate, EW System cells may use compacted clay liners. Where EW and other EW System cells are placed in a drained and decommissioned lagoon during the upgrade of a lagoon-based WWT system, the lining of that lagoon may be sufficient, reducing engineering and construction costs. EW cells (and the other cells of EW Systems) may be surrounded by berms of excavated or imported material made impervious by clay or geomembrane lining. Berm slopes may range from 3:1 to 1:1 inside EW cells. Another common Stantec construction method for them involves erecting vertical plywood sheeting on which a plastic liner is attached before the cell’s substrates are put in. (The wood outside the liner eventually degrades away but by then the inner substrate and outside soil with the liner between them then serve as the cell sides.) Water levels in the cells of EW Systems are controlled by swivel standpipes or adjustable weirs located inside concrete control structures. For its EW System projects, Stantec has developed sophisticated Technical Specifications and Construction Drawings, and these are provided to clients along with Design Basis Reports, Contract Documents, Construction Schedules, Operation & Maintenance Manuals, and Engineered Cost Estimates as part of

Tender and other project documentation.

EW Systems can be designed to meet even the most stringent effluent performance criteria for contaminant concentrations and toxicity, including if required, producing effluents meeting CCME and provincial drinking water quality guidelines. The ability to meet these high standards can be shown by on- or off-site treatability testing, and is demonstrated at dozens of successfully operating facilities. In addition, Stantec has been extending the EW System technology into the treatment of wastewaters which have already low, but still not low enough, concentrations of some specific contaminant of concern. For example it is carrying out a project for Newmont Canada to reduce dissolved molybdenum from about one mg/L (~1 ppm) in excess meteoric water from the tailings pond of a closed gold mine at Marathon, ON to a stringent discharge criterion of less than the Ontario Provincial Water Quality Objective (PWQO) of 20 µg/L (<20 ppb). It has already successfully demonstrated at


D-21

the Alfred Pilot Plant that such removals are possible in EW Systems, and is now planning to build a 500 m3/d on-site demonstration facility at the mine site. In another project carried out at the Fleming Pilot Unit for a confidential client, Stantec has demonstrated that a similar EW System configuration can reduce chromium in stormwater runoff from a closed industrial site from the 20 – 40 ppb levels to less than the PWQO for hexavalent Cr of one ppb. In both cases the design of the EW System is for an ABR EW cell (to remove the dissolved oxyanionic target metal) followed by an Aerated VSSF EW cell (to remove any co-contaminating ammonia and BOD, plus any breakdown products from the organic part of the substrate of the upstream ABR).

D.10 Treatability Testing

As every wastewater is different, pilot-scale treatability testing usually is required. (Treatability testing sometimes may be bypassed for well-categorized wastewaters such as municipal sewage.) Treatability testing has several purposes: 1) to show clients considering EW Systems that the wastewater that they wish treated can indeed be handled by such a system; 2) to conclusively demonstrate to regulators, bodies providing project financing, and other stakeholders that the ecotechnology is indeed viable and will produce the desired levels of treatment; and 3) to determine the kinetic and other scale up parameters needed to design and engineer subsequent full-scale facilities. Pilot-scale treatability testing can be carried out in an indoor pilot unit or in an outdoor pilot unit, or both, and such facilities may be located either at a client’s site (on site), or at a remote central pilot plant facility (off site). Indoor and outdoor pilot units each have advantages and disadvantages. Outdoor pilot units can be installed on-site and can treat an actual wastewater under the ambient conditions that a full-scale facility would encounter. However, varying temperatures, precipitation, feedstock contaminants’ concentrations, lighting and other field conditions make it difficult with an outdoor pilot unit to accurately determine the kinetic data and other scale up parameters needed. With indoor pilot units, a variety of confounding conditions (e.g., changing feedstock rate and contaminants’ concentration, temperature, lighting) can be fully controlled, allowing more accurate definition of kinetic data. Indoor, off-site pilot testing can then be followed by outdoor, on-site testing to confirm that the feasibility demonstrated in the indoor testing

will stand up under field conditions.

Some Stantec clients proceed by following indoor, off-site smaller scale pilot testing at a central Stantec test facility with somewhat larger scale, outdoor, on-site testing. Stantec’s Ecological Engineering Group currently has two central, pilot-scale EW test units available for treatability tests. The first, the Alfred Pilot Unit, is located at Campus D’Alfred of the University of Guelph located in Alfred, ON half way between Ottawa and Montreal. It is operated for Stantec by staff of the Ontario Rural Wastewater Centre (ORWC). The second, the Fleming Pilot Unit, is located at Frost Campus of Fleming College located in Lindsay, ON. The Fleming Pilot Unit is operated for Stantec by staff of the Centre for Alternative Wastewater Treatment (CAWT). Active R&D and development EW test programs are currently underway for Stantec at each. The facilities at Fleming College also include two outdoor, demonstration-scale


D-22

SSF CW/EW test trains. Stantec has also collaborated with the Mining and Mineral Sciences Laboratory of Natural Resources Canada (CANMET-MMSL) in Ottawa, ON in the operation of other bench-and pilot-scale EW treatment tests. The Alfred and Fleming Pilot Units, which can involve one or more indoor, one-cubic meter wetland and associated cells, can be operated for treatability tests with imported or synthetic wastewaters of all sorts. The two Stantec test units are associated with adjacent, comprehensive analytical laboratories that allow quick and relatively economic analyses of influents and effluents, as well as any related bench-scale testing that may be required.

D.11 The Effect of Temperature on EW Systems

Biological processes such as those in Engineered Wetlands are affected by water temperature and contaminant removal rates in them decline as temperature decreases according to the Arrhenius Equation (see Table D.10). The degree of decline varies depending on the process involved; nitrification in SSF CWs, for example, has an Arrhenius coefficient of 1.04 indicating moderate temperature effects while insulated, below ground, aerated SSF EWs have an ammonia nitrogen Arrhenius coefficient of 1.02 indicating much less impacts. Accordingly, Treatment Wetlands exhibit poorer contaminant removal performances in colder weather. There are several design/operational methods to mitigate the effects of lower temperatures in CW and EW Systems. Operations may be restricted to warmer weather periods. Deep water above the wetland surface may be used in winter to protect/insulate the biological components. SSF CWs may be used instead of Pond or FWS CWs, as the treatment of wastewaters below the surfaces of solid substrates are naturally better insulated. And the surfaces of SSF wetlands may be actively insulated with layers of mulch, peat or compost to retain heat, and keep originally warm wastewaters (e.g., sewage, leachates) being treated as warm as possible as long as possible. All of these strategies are used by Stantec in designing SSF EW Systems, and it designs them to operate throughout the winter whatever the ambient air temperatures by carrying out appropriate heat balances. The Company has great expertise in designing EWs which can and will operate throughout the severest winter conditions. The radial, aerated HSSF EW at Caspar, WY is one example of a system designed by a Stantec affiliate that operates continuously, summer and winter, even when air temperatures drop as low as -35°C and water temperatures are just above freezing. The following figure shows temperatures of sewage influent (top red curve), HSSF EW effluent (lower green curve) and ambient air temperatures for the SSF EW cells at Lutsen Sea Villas, a de-centralized WWT system for a lodge and townhouse complex on the south shore of Lake Superior that was designed and is operated by the Company. As may be seen, the wetlands continue to operate successfully without freezing even when winter ambient air temperatures on the South shore of Lake Superior drop below -10°F. Stantec and its affiliates have designed and operated dozens of such wetland treatment systems in all seasons.


D-23

Figure D-1: Heat Balance for Lutsen Sea Villas SSF EW System

For design, the EW cells of Stantec’s Alfred Pilot Unit can be heated or cooled (the latter by placing the cells in a walk-in refrigerator) to obtain kinetic data at the highest temperature that a wastewater being treated may be at in summer and lowest it may experience in winter. The following tables present treatability test data for the treatment of sanitary sewage from the Town of Alexandria, ON in a single Aerated VSSF EW cell (Jacques Whitford, 2005b). Table D.7 is for influent and effluent concentrations for the main contaminants for treatment during the High Temperature Runs of a Treatability Test at 25 °C. Table D-7: Summary of High Temperature Results for Alexandria Treatability Test

TREATABILITY TEST RESULTS HIGH TEMPERATURE RUNS

Concentration Influent Effluent Removalmg/L mg/L %

NH3-N 9.3 0.2 97.5

NO3-N 2.7 17.0 -

TKN 13.5 2.8 79.1

ORG-N 4.2 2.6 38.7

cBOD 16.0 4.7 70.8

TSS 26.7 11.4 57.4

Dissolved O2 3.4 5.7 n/a

Using these results, the rate constants for the removal of the main wastewater contaminants in the EW were calculated and these are presented in Table D.8.

-10

0

10

20

30

40

50

60

70

80

22/08/2000 26/09/2000 31/10/2000 05/12/2000 09/01/2001 13/02/2001 20/03/2001 24/04/2001 29/05/2001 03/07/2001 07/08/2001 11/09/2001

Te

mp

era

ture

de

g F

Lutsen Sea VillasWetland Temperature Monitoring

Air

Inlet


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Table D-8: EW Rate Constants for High Temperature Runs with Alexandria Sewage

TREATABILITY TEST RESULTS – HIGH TEMPERATURE RUNS

VOLUMETRIC RATE CONSTANTS (day-1)

PFR CSTR 2TIS

NH3-N* 3.3 38.5 10.0

cBOD 1.1 2.1 1.5

TSS 0.9 1.8 1.1

ORG-N 0.4 0.5 0.5

* Adjusted for impact of Org-N

As may be seen from Table D.8, similar results were obtained for the testing of the EW pilot unit located in the walk-in refrigerator at low temperatures (averaging °6 C). Table D-9: EW Rate for Low Temperature Runs with Alexandria Sewage

TREATABILITY TEST RESULTS – LOW TEMPERATURE RUNS

VOLUMETRIC RATE CONSTANTS (day-1)

PFR CSTR 2TIS

NH3-N* 3.0 29.4 8.4

cBOD 1.3 3.1 1.9

TSS 1.3 2.9 1.9

ORG-N 0.2 0.2 0.3

* Adjusted for impact of Org-N

The results from the low and high temperature runs were used to determine the Arrhenius coefficients for treatment in the aerated EW cells and these are presented in Table D.10. Table D-10: Arrhenius Coefficients for the Alexandria Treatability Test

TREATABILITY TEST RESULTS –CALCULATION OF ARHENNIUS

THETAkT = k20 C.

(T – 20)

Test Literature*

NH3-N 1.02 1.04

cBOD 0.99 1.00 (BOD)

TSS 0.97 1.00

ORG-N 1.04 1.05

* Kadlec & Knight, 1996

As may be seen from Table D.10, the Arrhenius coefficients for pollutant removals in Aerated SSF EWs are lower than those reported in the literature for ordinary SSF CWs.


D-25

This should not be surprising as similar low Arrhenius coefficients are found for pollutant removals in the highly oxygen-saturated environments of the aerated tanks of conventional activated sludge-type WWTPs, most of which operate outdoors. Other SSF EW treatability testing has confirmed these results and recent testing by Stantec associate, Nelson Environmental, which has developed an advanced version of the aerated EW technology which it refers to as a Submerged Aerated Growth Reactor™ (SAGR) which it uses in conjunction with its advanced aerated lagoon technology to treat municipal wastewaters, often for upgrading lagoon-based wastewater treatment systems. With outdoor SSF EW cells treating lagoon effluent near Winnipeg, MB last winter at temperatures as low as 0.5 °C it continued to demonstrate rate constants 5 to 10 times those possible in ordinary CWs. It appears that the aerobic bacteria responsible for the removals of oxidizable pollutants in aerated EWs, although slightly negatively affected by lower temperatures, compensate by greater numbers in the colder, but more oxygen-rich waters. Table D.11 summarizes the rate constant results of ammonia nitrogen and cBOD for the

Alexandria treatability test and compares the results with those for an ordinary SSF CW.

Table D-11: Summary of Rate Constant Results for Alexandria Treatability Test

AVERAGE CW/EW PERFORMANCE ENHANCEMENT

(PFR Removal Rate, day-1, North Glengarry Pilot Testing)

cBOD NH3-N

Ordinary CW - 0.3*

EW @ 25 ºC 1.1 3.3

EW @ 6 ºC 1.3 3.0

* Kadlec & Knight, 1996, θ = 1.04

As may be seen, although there is some effect on the rate constant for ammonia nitrogen removals at lower operating temperatures in SSF EW cells, the absolute rate constants are still 10X those found in ordinary SSF CWs.

D.12 Sludge formation in EW Systems

Substrate beds in SSF EWs may become reduced in hydraulic throughput, or even clog, if: 1) substrate particle sizes are too small; 2) inorganic material accumulates in or on the substrate beds; 3) chemical precipitation leads to the deposition of material between the substrate pores; and/or 4) the rate of organic sludge (microbial biomass) accumulation exceeds the autolysis rate. Early kinds of SSF CWs used soil as their substrate but the small pore spaces that this medium involves often led to clogging and/or channeling. Most modern SSF CWs use gravel or some similar higher pore space aggregate as their substrates, and clogging due to too small pore spaces is no


D-26

longer a problem in well-designed systems. Beds in Sub-Surface Flow Wetlands can be easily replaced if clogging occurs but in most cases this would not be expected to occur for very many years (20+) in well-designed CW and EW systems. An exception to the avoidance of clogging due to too small pore space sizing are vertical downflow biosolids stabilization (reed bed) sludge dewatering EWs that treat liquid municipal and industrial by-product sludges (0.5 – 2% solids) called biosolids. These kinds of EWs are designed to “clog”. They have an upper layer of sand above increasingly larger particle size layers of gravel. These periodically-dosed wetlands do not require continuous flow, and the reeds growing up through the upper sand layer help to maintain liquid percolation while the solid materials in the biosolids are trapped above and in the sand layer. Inorganic material (i.e., suspended solids) will only clog SSF CW and EW beds if it is not first removed to low levels upstream of the wetland cells, and the prevention of such situations is a matter of judicious treatment wetland system design. Similarly, reduced hydraulic conductivity/clogging of SSF EW substrate beds due to chemical precipitation also can be prevented/mitigated by proper consideration of chemical and process conditions. It is not a problem in most SSF EWs treating most wastewaters. (An example of a situation where chemical precipitation can be a problem is in the wetland treatment of acid rock drainage, ARD, containing dissolved ferrous iron that can oxidize to ferric hydroxide precipitates if exposed to oxygen in the wetland at certain pH levels. Even in such situations, advanced wetland design methods can deal with these kinds of problems.) The last potential for reduced SSF EW hydraulic conductivity/clogging is that due to the formation of excess organic sludge (i.e., microbial biomass) in the biofilms that bridge, then fill the pore spaces between the substrate particles. Like other kinds of biofilters, SSF CWs/EWs may be regarded as kinds of attached growth systems. However, the comparison should not be carried too far as EWs are generally much more massive than other attached growth systems such as biofilters, and usually operate at very much lower local loading conditions. Any “excess” sludge formed in SSF EW can be quickly degraded by aerobic and anaerobic phytoremediation processes such as phytodegradation (plant-induced organics degradation) and rhizodegradation (plant-mediated microbial organics degradation due to enhanced populations of heterotrophic bacteria in the wetland plant root zones). Accordingly, the accumulation of excess sludge in the beds of well-designed SSF EWs does not usually occur at levels that will clog the beds, or even seriously impede hydraulic conductivity. Even fears that such excess sludge will slough off continually into effluent from the wetlands where it will report as a TSS and BOD have proved to be unfounded. Attempts to directly compare SSF EWs with other kinds of attached growth technologies as to parameters such as biofilm area per unit of pollutant loading are a mistake and should not be entertained (Kadlec & Knight, 1996). However, it is cautioned that there are other kinds of sludge formed in WWT systems than that formed in the biological treatment step(s). Inorganic and other sludges may be formed in other cells of EW Systems than the EW ones and such will require management.

APPENDIX E PHOSPHORUS REMOVAL


E-2

E.1 Lake Simcoe Protection Plan

Human activities have influenced the Lake Simcoe watershed for over 200 years and increasing anthopogenic effects are leading to the europhification of the lake. To mitigate the impact of excess phosphorus into Lake Simcoe, the Government of the Province of Ontario passed the Lake Simcoe Protection Act in 2008. This act provides authority for the establishment and later amending of a Lake Simcoe Protection Plan (the Plan) (MOE, 2009). The Plan addresses key environmental problems associated with the lake including stresses, from human activities, stresses from excess levels of phosphorus entering the lake, and the losses of sensitive natural areas and habitat in and around it. The LSRCA is a key partner with the MOE in the implementation of the Plan. As part of this implementation, the MOE, the LSRCA and other key stakeholders are drafting a comprehensive Lake Simcoe Phosphorus Reduction Strategy (MOE, 2010). Its purpose is to reduce the average 2002 – 2007 phosphorus loading into the lake of 72 t/yr to a target level of 42 t/yr, and to restore deep water dissolved oxygen levels in the lake to 7 mg/L. (Without action, phosphorus loadings are forecast to rise to 94 t/yr. Historical loadings into Lake Simcoe in the 1800s are estimated to have been 32 t/yr.) The Canadian federal government via Environment Canada has established the Lake Simcoe Clean Up Fund (LSCUF) to partially fund initiatives supporting the Plan. As part of its mandate the LSRCA seeks out projects to forward the objectives of the Plan and, in cooperation with industry, local governments, universities, NGOs and other parties it makes proposals to Environment Canada for funding under the LSCUF which it also supports with funding from its own and other sources. The Project described in this Report was such an initiative.

E.2 Phosphorus Basics

In the literature, the noun “phosphorus” is sometimes spelt “phosphorous”, but this alternate usage can be misleading as the adjective phosphorous correctly refers to the III valence state of the element (often compared to the V valence state adjective, phosphoric) and should not be used to describe the element as a noun. The main sources of phosphorus in municipal wastewaters are excreta and detergents/cleaning agents, although decaying organic matter, fertilizers, biocides, plasticizers, home care products, and chemicals can make contributions as well. Phosphorus is often quantified as total phosphorus (TP) and dissolved phosphorus (DP). The phosphorus in a wastewater may be found either as part of particulates (grit, suspended solids, colloids) in the water and/or as DP. The dominant form of phosphorus is ortho-phosphate (o-PO4) and this species, may be present as part of the particulates or as part of DP. Many equate dissolved phosphorus with ortho-phosphate (o-PO4) but this is not always the case. Although o-PO4 is usually the dominant kind of DP in most stormwaters and wastewaters, there are other kinds of DP including polyphosphates (Poly-P) from cleaning agents and other anthropogenic sources, as well as phosphorus-containing organic material (Org-P). Accordingly, total phosphorus is given by:


E-3

(E.1) where the ortho-phosphate concentration is expressed as phosphorus. Typically a municipal wastewater will contain 3 – 5 mg o-PO4-P/L, 1 – 3 mg Poly-P/L and <1 – 1 mg Org-P/L (Rybicki, 1997). As with o-PO4, Poly-P and Org-P in a wastewater may be present as part of particulates or in dissolved forms. Of concern is the fact that much of the non-o-PO4 DP (dissolved polyphosphates and organic phosphates) is capable of hydrolizing chemically and biologically to o-PO4 in aqueous media but this usually takes some time and, since many of the dissolved forms of non-o-PO4 species may be poorly (or not at all) removed in the usual kinds of phosphorus removal processes (e.g., alum sedimentation ponds), this may not occur until after this phosphorus has passed through them, reaching receiving waters and entering the environment. Ortho-Phosphate (o-PO4) may consist of the following species: H3PO4, H2PO4

-, HPO42-

and PO43- and may be reported as itself (e.g., mg o-PO4/L) or as phosphorus (mg o-PO4-

P/L) in the same manner that ammonia is often reported as ammonia nitrogen. In the case of phosphorus, results reported as mg o-PO4/L can be converted to mg o-PO4-P/L (allowing direct comparison with TP) by multiplying their concentrations by the ratio of their molecular weights (i.e., x 31/95). Ortho-phosphate is highly bio-available and functions as a “quick sugar” for the growth of algae and other microbes in stormwater and wastewater treatment facilities (Perry et al.) Polyphosphates involving P-O-P bonding and consisting of molecules with two or more phosphate atoms. They include linear polyphosphates, pyrophosphates and metaphosphates. Tripolyphosphates may consist of the following species: H3P3O10

2-, H2P3O10

3-, HP3O104-, and P3O10

5-, and complexes thereof (linear chains). Trimetaphosphates may involve HP3O9

2- and P3O93-, and complexes thereof (cyclic

compounds). Most polyphosphates come from detergents and cleaning agents. Most polyphosphates (and many organic phosphorus–containing compounds) undergo hydrolysis in aqueous solutions and revert to ortho-phosphates, however usually this hydrolysis is quite slow (Metcalfe & Eddy, 2004). Organic phosphorus (usually involving P-O-C bonding) includes easily decomposable (and hence readily bioavailable) species such as phospholipids, sugar phosphates, nucleotides, phosphoamides and a variety of other soluble phosphorus-containing species, and slowly decomposable organic phosphorus which may be relatively un-bioavailable (e.g., that in phytins, and humins). In stormwaters and wastewaters, much of the organic phosphorus comes from excreta and decaying organic matter. Org-P is a minor component of municipal wastewaters but can be an important constituent of some industrial wastewaters and sludges such as biosolids. There are two types of phosphorus in stormwaters and wastewaters: particulate-bound material and soluble (dissolved) phosphorus (DP), the latter also sometimes referred to as Soluble Reactive Phosphorus (although strictly speaking the term SRP should only apply to ortho-phosphate and some condensed phosphates). A significant part of the SRP will be bioavailable (>90%) so it sometimes also referred to as bioavailable phosphorus. It is the SRP and other kinds of DP (e.g., dissolved organic phosphorus


E-4

compounds) that can lead to eutrophication in receiving waters and levels as low as 20 ppb can support excess algal development. Particulate phosphorus is that which is removed by a 40 micron filter, and consists of phosphorus sorbed (bound) to suspended solids by physical and chemical means, and that incorporated in inorganic or organic particles. Precipitated particulate phosphorus may cause problems as organic materials containing it that settle out in primary stormwater and wastewater treatment facilities (e.g., in a stormwater wet pond) may later degrade, releasing their phosphorus back into the environment. In addition, research has identified that particulate-bound phosphorus in stormwater is concentrated in the finer parts of the suspended particulates, those in the 1 to 25 micron size range (Perry et al., Vaze & Chiew, 2004). Organic phosphorus may be particulate if it involves intact cell biomass, or dissolved if secreted by disintegrating dead cells.

E.3 Phosphorus Removal Processes

Phosphorus may be removed from stormwaters and wastewaters by the following physical, chemical and biological mechanisms:

SETTLING

CHEMICAL PRECIPITATION

FLOCCULATION/COAGULATION

SORPTION

BIOLOGICAL UPTAKE In many processes, combinations of the above basic removal mechanisms are the norm (e.g., in wetlands).

Simple settling in a lagoon, settling pond, tank or forebay will remove part of a stormwater’s or wastewater’s particulate phosphorus (generally 20 – 30% for municipal sewage and 50 - 70% for stormwater, although TP and DP can vary from 20% to more than 90% depending on the waters involved). Since about half of the particulates (mostly suspended solids) will settle out, about 10 – 15% of total phosphorus from a municipal wastewater and up to 35% of it in a typical stormwater (Perry et al.) can be removed in this manner. The problem with particulate-bound phosphorus is that the part of particulates settled out in ponds, etc. may be remobilized during later storm or other high flow events, and also that phosphorus in particulates that have settled may change into more soluble forms between events (i.e., the degradation of organic matter settled out on the floor of a stormwater dry pond). The use of oil-grit-sediment (OGS) separator vessels will enhance the removal of grit and suspended solids, and these have the added advantage of being cleaned out regularly, completely removing their phosphorus from the system. Advanced kinds of OGS vessels (e.g., Stormceptors™, Watergate™ Lamella OGSs) can remove all of the grit and 60 - 80% of the suspended solids (TSS) (allowing much larger amounts of influent TP to be removed by physical means) and can capture particles down to 20


E-5

microns and smaller. Stantec’s Engineered Stormwater Wetlands (ESWs, see Appendix D.3) use this method to remove phosphorus (Higgins et al., 2010b).

Adding certain chemicals (calcium, aluminum and iron salts) to precipitate insoluble phosphate compounds represent other common phosphorus removal methods. Used as a primary WWT process, chemical precipitation can achieve effluent TP concentrations from 0.3 to 1.0 mg/L. (Chemical precipitation can also be used as part of one- and two-stage advanced tertiary WWT processes, and even part of certain types of secondary wastewater treatment processes, see below.) There are a variety of metals salts used for phosphorus removal by chemical precipitation and each works best in narrowly defined pH ranges. Metal salts can be added by dispersing them as solids into WWT lagoons, injecting them as liquid solutions into the wastewater feeds into lagoons or specially-designed sedimentation ponds (including ones functioning as cells of EW Systems), or injecting them as liquids into the tanks of mechanical WWTPs. Metal salts remove dissolved phosphorus from stormwaters and wastewaters largely by the direct precipitation of ortho-phosphates. With them, the phosphates removed from aqueous solution end up as phosphate minerals including for example calcium phosphate (hydroxyl apatite), octacalciumphosphate, β-tricalciumphosphate, brushite, monetite), aluminum phosphate (variscite), iron phosphate (vivianite, strengite), and manganese phosphate (MnHPO4), compounds (Baker, 1996). Associated with the precipitation reactions are flocculation, coagulation and sorption mechanisms that facilitate the removal of the precipitates, as well as any remaining particulates in the water. With all them, sludges are formed, and the management of these sludges is a significant factor in the use of chemical precipitation for phosphorus removal. Other difficulties with using metal salts for removing phosphorus from aqueous media include the amounts and costs of the chemicals. Often high molecular weight polymers are added to metal salt-based primary phosphorus removal processes to enhance flocculation, coagulation and settling (and hence phosphorus removal). Commercially-available polymers used include polyacrylamides, polyacrylic acid, polyvinyl alcohol, polymethacrylic acid, and many more as well as various co-polymers of them. The overall advantages and disadvantages of phosphorus removal using metal salts during primary, secondary and tertiary processes are reviewed in Metcalfe & Eddy (2004).

The most common trivalent metal salt used for phosphorus removal is alum which is nominally Al2(PO4)3.18H2O, although actual hydration ranges from 14 (MW, 594.4 gm/mole) to 18 (666.5 gm% Al2O3) (Metcalfe & Eddy, 2004). The nominal chemical equation for alum’s reaction with ortho-phosphate for the 14 hydrate is given by (Pycha & Lopez, 2008):


E-6

(E.2)

A more general equation is: (E.3)

The weight ratio of the above reaction is 0.87:1, Al:P. For example, the quantity of alum needed to react with 10 mg/L of alkalinity is 10 mg/L x {3 x 1000 gm/mole/666.5 gm/mole} = 4.5 mg/L. A curve showing the relationship between the concentration of DP during alum dosing is provided on page 503 of Metcalfe and Eddy (2004). Actual reactions during alum-based phosphorus removal are more complex, also involving the co-formation of hydroxide salt complexes which may in turn sorb further phosphate (Rybicki, 1997). When added to water with calcium or magnesium alkalinity, the formation of such aluminum hydroxide flocs is a major factor, as they carry down phosphorus (and other contaminants) during their settling: (E.4) The use of alum for phosphorus removal achieves the best results in the 5.5 to 6.5 pH range, doesn’t do well over about pH 7, and operates poorly from pH 3 to pH 5.5. In some facilities, acids or caustic (more common) can be added to a wastewater to ensure an optimum pH for alum-based phosphorus removal. Various factors affect the actual quantities of alum required including alkalinity, the final pH required, the presence of various ions in the water being treated (i.e., sulphates, fluorides, sodium), the quantity and nature of the suspended solids in the water, the presence and amounts of microorganisms present, the intensity of mixing, and a variety of other aspects. Typical dosages are 75 – 250 mg/L (Metcalfe & Eddy, 2004). A company called Seprotech has developed a tertiary treatment version of the alum technology using polyaluminum sulphate (PASS), a kind of partially hydrated alum. This technology is claimed to require less pH adjustment and lower dosages than alum or ferric chloride, and can be delivered either in packed columns or removable cartridges. The PASS technology is claimed to achieve effluent concentrations of <0.02 mg TP/L.

Ferric chloride reacts with ortho-phosphate to form ferric phosphate: (E.5)

The stiochiometric weight ratio of the above reaction is 1.8:1 Fe:P. Similarly to alum, calcium or magnesium alkalinity leads to the formation of a ferric hydroxide floc that also carries down phosphorus (and other contaminants) during its precipitation: (E.6)


E-7

The use of ferric chloride for phosphorus removal achieves the best results with wastewaters with pHs in the 4.5 to 5.0 range. Ferric chloride is usually supplied as approximately 20% liquid solutions, often as byproduct streams from iron and steel production. Typical dosages are 45 – 90 mg/L (Metcalfe & Eddy, 2004).

Lime (either as CaO or Ca(OH)2) is not used much in to remove phosphorus from municipal wastewaters but rather from ones which tend to more alkaline. If the wastewater’s pH is >10, added lime will react with ortho-phosphate to produce hydroxyl apatite: (E.7)

Generally the quantity of lime required for effective phosphate removal is 1.4 to 1.5 times the influent wastewater’s alkalinity expressed as CaCO3 (~ 200 - 400 mg/L). Lime is available as lump (63 – 73% CaO), powder (85 – 99% CaO) or as a slurry (15 – 20% CaO) (Metcalfe & Eddy, 2004). Phosphate removal using lime rarely results in effluents containing less than 1 mg TP/L.

In addition to ferric chloride, there are two other iron salts sometimes used for phosphorus removal from wastewaters: ferric sulphate, Fe2(SO4)3, and ferrous sulphate, FeSO4.7H20. Ferric sulphate is available in granular form (18.5% Fe) and works best in wastewaters in the 4 to 5.5 pH range, while ferrous sulphate is also available in granular form (20% Fe) and works best in wastewaters in the 7 to 8 pH range (Metcalfe & Eddy, 2004). Ferrous sulphate is also used in combination with lime but there are many problems with the use of this combination. (Lime is sometimes also used in conjunction with ferric chloride and ferric sulphate as well.)

Secondary wastewater treatment processes used in most larger (a few thousand m3/d up to tens of thousands of m3/d) mechanical wastewater treatment plants (WWTPs) are versions of the activated sludge (AS) process. There are many variations of the AS process including continuous (e.g., the Extended Aeration process) and intermittent (e.g., sequencing batch reactor, SBR, processes) feed flow versions. In its most basic form, the secondary treatment part of an AS-based WWTP consists of an open aeration tank (in which bacteria and other microorganisms degrade the wastewater’s organic matter) and a secondary clarifier vessel. (Primary clarifiers at mechanical WWTPs are part of the plant’s upstream primary treatment processes.) The secondary clarifier settles out excess biomass (i.e., mostly living and dead bacteria at this point) known as activated sludge, and part of this material is pumped back to the aeration tank joining influent there and promoting the biological reactions in the aeration tank. The amount of activated sludge produced is always greater than that needed for recycle and part of it has to be “wasted” as waste activated sludge (WAS) which must be


E-8

managed and disposed of. Indeed, as was mentioned, the management of WAS at most mechanical WWTPs is the largest part of their operating costs. Microbial cells are about 3% phosphorus on a dry weight basis. If biomass at AS plants can be expressed as C118H170N17P, then it is clear that the removal of the WAS will lead to the removal of some of the influent wastewater’s phosphorus as well. Since the carbon:phosphorus ratio (C/P) in the WAS is about 100, effectively just over one unit of phosphorus will be removed for every 100 units of BOD. Assuming a typical municipal wastewater contains ~ 250 mg BOD/L and 5 – 15 mg TP/L and a basic AS process removes 90% of BOD, it can be seen that for an AS process roughly about 20% of the influent’s phosphorus can be removed with the WAS (i.e., 10 mg TP/L would be reduced to ~8 mg/L) (Jiang et al., 2004). Many AS-based WWTPs have been upgraded to remove larger amounts of nutrients (especially nitrogen) using biological nutrient removal (BNR) processes. In its most basic form, this is the two-stage activated sludge (AO) process involving placing an anoxic tank in front of the aeration basin. This allows nitrates in the recycled sludge to be removed by de-nitrification and also improves phosphorus removal from the ~20% of the AS process to about 45% (Jiang et al., 2004). There are patented versions of the AO process available (e.g., the A/O™ process and the Phoredox™ process). When activated sludge processes are enhanced for phosphorus removal, the promotion of the growth of Phosphate Accumulating Organisms (PAOs) in the tanks is always involved. PAOs are microbes which take up phosphorus in excess of normal biological needs (so-called “luxury uptake”) A further, refinement of the AO process, an example of something called enhanced biological nutrient removal (EBNR), is the AAO process which involves inserting a third tank, one designed to promote anaerobic reactions, before the anoxic and aerated tanks of the WWTP’s secondary treatment train (the three-stage sequence is then anaerobic-anoxic-aerated before the clarifier), and arranging an internal recycle from the outlet of the aerobic tank back to the inlet of the anoxic tank. (This is in addition to the main recycle of activated sludge, now back from the clarifier to join feedstock entering the initial anaerobic tank.) With the AAO process, more than 60% phosphorus removal is possible reducing effluent phosphorus to the 1 mg/L region. As with the AO process there are patented versions of the AAO process (e.g., the A2/O™ process, the Virginia Initiative Plant [VIP] process, and the University of Cape Town [UCT] process). There are even more complex EBNR processes available such as the five-stage modified BardenPho process which involves anaerobic-anoxic-aerobic-anoxic-aerobic tanks, with recycle from the exit of the first aerobic tank to the inlet of the first anoxic tank (Metcalfe & Eddy, 2004). The ultimate in EBNR is to add a tertiary treatment stage involving a membrane process after an AAO process. Combinations of ultrafiltration and reverse osmosis (with pre-treatment) after AAO can reduce phosphorus by >98%, resulting in effluent TP concentrations of 0.05 mg/L. This comes at a price: the capital costs of such EBNR WWTPs are in the order of twice the cost of ones with ordinary AS processes for their secondary treatment steps (Jiang et al., 2004).


E-9

Another way that the three-stage AAO process can be enhanced by incorporating metal salt precipitation into it. The usual metal salts (See Section E.3.3) can be added to an aerobic tank to supplement biological phosphorus removal with chemical precipitation. With the addition of a tertiary clarifier into which polymer is added to further enhance removal, of phosphorus, up to 87% with influent total phosphorus can be removed resulting in effluent levels in the 0.5 mg/L range. A patented version of this process is the PhoStrip™ process. Other AAO combination processes with added tertiary treatment involve inserting a backwashed filter after the secondary clarifier (effluent TSS approaching 1 mg/L and TP of <0.15 mg/L), or placing a backwashed (with NaOH) alumina sorption column there as the last step (96% removal to 0.01 mg TP/L) In addition, for moderate wastewater flows (1,000 – 5,000 m3/d), there are advanced tertiary phosphorus removal processes involving one- and two-stage continuous backwash filters which combine phosphorus removal by adsorption, precipitation and filtration. Examples are Parkson’s Dynasand process and Bluewater Technology’s BluPro™ process, both of which are claimed to be able to reduce effluent phosphorus levels to as low as 0.05 mg TP/L. However, these processes may be relatively expensive from both capital and O&M bases for smaller wastewater flows, and may be difficult to use in smaller applications such as de-centralized WWT systems. One group of tertiary phosphorus removal processes that may be more suitable for these smaller cases are physical-chemical sorption processes such as ones using steel slag and such is the main focus of this Report.

Sorption is a mass transfer process which transfers a material from the liquid phase to the solid phase, and is a combination of physical-chemical interactions which include adsorption, absorption and surface complexation (Perry et al.). For phosphate removal, sorption-based processes are particularly effective in removing dissolved phosphorus. There are various kinds of phosphorus sorbents used, both by themselves (un-promoted) and amended (promoted using carriers and/or co-precipitants) to enhance phosphorus removal. (E.g., ordinary silica sand is a poor phosphorus adsorbent but promoted with iron salts, sand is used in several phosphorus removal processes.) Iron & steel slags (Mann, 1997), blast furnace slag and cement clinker (Calder et al., 2006), gypsum, activated alumina, red mud, activated carbon, crushed crustacean shells, shales (Lemon et al., 1996), lightweight aggregates (Zhu et al., 1997), zeolites (Sakadevan & Bavor, 1998), bentonite, ferric (hydr)oxides, diatomaceous earth, and various sands (Perry et al.) can all be used promoted and unpromoted as phosphorus adsorbents. The co-precipitants with which many adsorbents are promoted allow the rapid adsorption of phosphorus on their surfaces, followed by its slower incorporation into the crystal structures of the co-precipitants (Xiong & Peng, 2008). Carrier (binder) materials are co-precipitants which incorporate (sorb) phosphorus into their structures using adsorption, other sorption mechanisms and encapsulization. They are particularly useful where the adsorbent is a more exotic metal salt that may be (or


E-10

may be perceived to be) toxic, as the sorption/encapsulization process can mitigate such toxicity. Lanthanide salts (chlorides, nitrates) are an example claimed to be very effective in removing phosphates from water by precipitation/adsorption then encapsulation when combined with bentonite clay, but whose potential toxicity is a matter of concern. These form the basis of the patented Phoslock™ process. (Other versions of such processes use diatamonaceous earth, alumina, silica and zeolites as the carriers.) A sorption medium’s ability to capture and retain a targeted pollutant will be a function of type, specific surface area, porosity, gradation, the presence or absence of associated support media, organic content and several other factors, Sorption is defined by four descriptive performance factors: adsorption isotherms, reaction kinetics, breakthrough, and in some cases, desorption. The capability of a sorption reactive medium is quantified by Adsorption Isotherms which define the available sorption capacity of the medium for a given pollutant for a known quantity of medium and volume of water being treated over a fixed period of time, based on testing under controlled conditions. Traditionally, the Freundlich or Langmiur Isotherms have been used to define this aspect, although there are now more advanced formulations available. The Freundlich equation is given by: (E.8)

where X is the amount of the compound being adsorbed (the adsorbate, ortho-phosphate in this case) in units of weight per weight of the adsorbent (e.g., steel slag reported as mg/gm or gm/kg), and C is the equilibrium concentration of the absorbant. In the liquid phase in mg/L after adsorption (Mecalfe & Eddy, 2004). Kf is known as the Freundlich capacity factor and 1/n the Freundlich intensity factor. The constants of the Freundlich equation (Equation E.8) may be determined using a shaker test and plotting log X against log Kf + 1/n.log C. The Langmuir equation is given by:

(E.9)

Where K1 is the adsorption maximum and K2 is related to the binding energy (Mann, 1997). The constants of the Langmuir equation also can be determined using a shaker test and plotting C/X vs 1/K1K2 + C/K1. For some adsorbents, the Freundlich equation (Equation E.8) is a better measure of sorption, while for others the Langmuir Equation (Equation E.9) is (Mecalfe & Eddy, 2004).


E-11

E.4 Steel Slags

Iron and steel slags are produced as the non-metallic co-products of iron and steel production (NAWE, 2002, Banks et al., 2006). There are three kinds of these slags, each named for the process from which it is produced: Blast Furnace iron slag (BF slag), Basic Oxygen Furnace (BOF) steel slag (BOF slag), and Electric Arc Furnace (EAF) steel slag (EAF slag). All three are composed of impurities separating from the ores used plus fluxing agents (mainly lime from limestone) which rise above the molten metals during production. Table E.1 compares some average metal compositions in the three slags by Proctor et al. (2000) who performed a detailed characterization of slag from 58 active BF, BOF and EAF mills which accounted for more than 47% of the total iron and steel industry slag generated in North America. Table E-1: Typical Steel Industry Slag Metal Characterizations (mg/kg)

Slag BF BOF EAF

Aluminum 41,425 23,841 35,009

Antimony ND 3.3 4.0

Arsenic 1.3 ND 1.9

Barium 273 75 557

Beryllium 8.2 0.5 1.1

Cadmium ND 2.5 7.6

Calcium 273,855 280,135 250,653

Carbon 2,279 2,600 2,936

Chromium (total) 132 1,271 3,046

Cobalt 3.0 3.8 4.8

Copper 5.3 30 178

Iron 17,355 184,300 190,211

Lead 3.6 50.0 27.5

Magnesium 69,991 55,318 54,460

Manganese 5,527 32,853 39,400

Mercury ND 0.1 0.04

Molybdenum 0.8 11 30

Nickel 1.4 4.9 30

Phosphorus 220 3,197 1,781

Selenium 3.9 15 18

Silicon 170,064 59,653 74,524

Silver ND 9.1 8.4

Sulphur 10,268 1,112 1,891

Thallium ND 7.2 11

Tin 1.6 6.5 10

Vanadium 54 992 513

Zinc 20 46 165

ND = non-detect


E-12

The slag by-products may be landfilled, or screened and classified for use as aggregates in civil engineering applications (Bayer, 1994). As may be seen from Table E.1, they mainly consist of silica and alumina (from the ores) along with calcium and magnesium oxides (from the fluxes). Also, the steel slags are higher in manganese and iron and lower in silicon and sulphur than the BF slag. Mikhail et al. (1994) indicated that BOF slag is a relatively homogeneous material containing elevated concentrations of calcium, iron, magnesium, silica and alumina, primarily in the form of dicalcium silicates, ferrous oxide, and complex ferrites and silicates. The major components (>10 wt%) of BOF slag are di-calcium silicate(Ca2SiO4), tri-calcium silicate (Ca3SiO5), ferrous oxide (FeO), and Ca-Mg-Mn-Zn-ferrite (Ca,Mg,Mn,Zn)Fe2O4. Other components (5 - 10 wt%) of BOF slag include calcium hydroxide (Ca(OH)2), calcium-ferrite (Ca2Fe2O4), and magnesium ferrite (MgFe2O4). Minor components (<5 wt%) include silicon dioxide (SiO2), aluminum silicate (3Al2O3SiO2), calcium aluminum silicate (CaO•Al2O3•2SiO2), magnesium oxide (MgO), calcium oxide (CaO), di-calcium-aluminum-silicate (2CaO•Al2O3•SiO2), calcium-iron-oxide (CaFeO2), magnesium-manganese-ferrite ((Mg,Mn)Fe2O4), manganese-iron-oxide (MnFeO), and metallic iron (Fe) (Proctor et al., 2000; Mikhail et al., 1994). If water passes through BOF or EAF slag, the resulting leachate will contain tufa, a form of calcium carbonate. This is the result of the presence of lime in the interstices between the slag particles. When such leachate is exposed to carbon dioxide in the air, it forms the tufa. The leachates are quite high in pH (>12) and, although actual compositions will depend on a variety of factors (e.g., mill, ore, pH, particle size, contact time), may contain some

trace metals as are illustrated in the following data (Proctor et al., 2000, NAWE, 2002)

and compared to Ontario Provincial Water Quality Objectives (PWQO). Table E-2: Typical Slag Leachate Trace Metal Characterizations (mg/L)

Slag BF BOF EAF PWQO

Aluminum 3.8 2.7 38 0.005 – 0.1

Antimony ND ND 0.017 0.02

Arsenic ND 0.003 0.004 0.005

Barium 0.22 0.11 0.49

Beryllium ND ND ND 1.1

Cadmium ND ND ND 0.005

Chromium (total) 0.0038 ND 0.066 0.0089

Copper ND ND ND 0.001 -0.005

Iron ND ND ND 0.3

Lead ND 0.027 0.018 0.005

Manganese 0.0014 0.0022 0.0035

Mercury ND 0.008 ND 0.0002

Molybdenum ND ND 0.044 0.04

Nickel ND ND ND 0.025

Selenium 0.0075 ND 0.011 0.1

Silver 0.0037 ND ND 0.0001

Thallium ND ND ND 0.0003


E-13

Tin ND ND ND 0.01

Vanadium 0.01 0.0087 0.015 0.006

Zinc ND ND ND 0.02

ND = non-detect

This above characterization indicates that although the slags contained elevated concentrations of metals and/or metalloids relative to natural soil (antimony, cadmium, total chromium, manganese, molybdenum, selenium, silver, thallium, tin and vanadium), these metals and metalloids are not readily leached from them, although vanadium needs to be watched. Iron and steel slags have been demonstrated to be effective for the removal of phosphate from wastewater in previous studies (Higgins, 1997, IRAP, 1999). Speciation calculations, mineralogical characterization and literature comparisons identified that the main mechanisms of the phosphate removal are related to calcium phosphate precipitation and to adsorption of o-PO4 onto the surfaces of slag particles. (Baker et al. 1997). Thus the governing reactions would be related to one of the following calcium phosphate mineral forming reactions (Baker et al. 1998):

-19.24= Ksplog H+ PO+Ca=CaHPO monetite

-18.91= Ksplog H+O H2 + PO+Ca= O2H CaHPO brushite

-28.94= Ksplog PO2 +Ca 3=)(POCa te)(whitlocki phosphate tricalcium

-93.95= Ksplog H2+ PO6+O H5 +Ca 8=O H5 )(POHCa :phosphate moctacalciu

40.41- to-44.20= Ksplog OH+ PO3+Ca 5= H+OH)(POCa :titehydroxyapa

+-3

4

+2

4

+2

-3

4

+2

24

-3

4

+2

243

+-3

42

+2

26428

2

-3

4

+2+

345

The solubility of calcium phosphate phases under neutral to alkaline pH conditions increase generally in the following order: hydroxyl apatite (HAP), β-tricalcium phosphate (TCP), octa-calcium phosphate (OCP), monetite, and brushite (Graham et al., 1993). It is desirable to remove the free lime (and MgO) before a slag is used to remove phosphorus. This can be accomplished either by weathering and/or washing (preferably both). Weathering should involve storing the slag uncovered outdoors (preferably after screening to remove fines and classification into suitably sized aggregate particles). After six to nine months of weathering, the free lime will be converted to tufa (which can be later washed out) and will stabilize at about a few percent of its initial concentration (Thomas, 1979, Banks et al., 2006). Because of potential cementation, piles of slag being weathered should be periodically turned and broken up. After the weathering process is complete, the slag should be again screened and washed before use. Despite pre-washing, some lime [CaO and Ca(OH)2] will still be present in weathered and washed slags, at least initially. Dissolution of these components will significantly increase the pH of any water passing through a bed of such slag (to as high as pH~12+) and the concentration of Ca in solution (Baker et al., 1998). (E.10)


E-14

At these high pHs, hydroxyl apatite is the most likely phosphate-containing precipitate to form. Some will be washed from the slag bed but much will be retained on/in the bulk of the slag. (E.11)

However, over time as the residual free lime is used up, the pH should drop to below 10 and the potential for cementation and plugging when using it becomes greatly reduced. Properly prepared, the bulk of phosphate removal should be by sorption at rates of about 2 - 3 gm PO4/kg slag (Higgins, 1997, IRAP 1999).

The Langmuir Equation (E.9) has been claimed (Sakadevan & Bavor, 1998) to be valuable for assessing phosphorus sorption on steel slag than the Freundlich Equation (E.8) since it defines an adsorption maximum and this is said to represent the highest possible levels of adsorption which might be expected in a particular system. However, for practical SSF wetland cell sizing work, it was found (IRAP, 1999, Higgins, 2000) that the Freundlich Equation was more appropriate. It may be considered a hypothetical index of phosphate sorbed from a solution having a unit (1 mg/L) equilibrium (i.e., effluent) phosphate concentration. This may be taken to provide a measure of the relative phosphate adsorption capability of a slag and can be used to determine the volumes of it needed to remove specified amounts of phosphate from wastewaters over defined periods. The following table compares shaker test results found for two samples of BOF slag (BOF-1 and BOF-2) used during the BREW Project (see Appendix D.4) with reported Australian results (Wood & McAtamney, 1996, Mann, 1997, Sakadevan & Bavor, 1998): Table E-3: Isotherm Results For Steel Slags (mg PO4/g substrate)

Substrate Freundlich Kf Langmuir K1

BOF-1 2.3 25.4

BOF-2 3.2 15.2

Steel Slag 2.44 1.43

Blast Furnace Slag 2.23 44.25

No other potential phosphorus sorbents that might be used in EW cells showed adsorptions as high as the various steel industry byproducts, the closest of anything else reported was that for natural zeolites which had Freundlich and Langmuir K values of 0.91 and 2.15 mg phosphate per gram respectively (Sakadevan & Bavor, 1998). The reason for the slags’ alkaline natures may be shown by representing the oxides which make up steel industry byproduct slags as R-OH. Then, the adsorption of phosphate from a wastewater passing through a bed of slag may be represented (very highly simplistically) by: (E.12)

where H3O

+ is the protonated (acid state) form of water.


E-15

E.5 The Phosphex Process

Basic Oxygen Furnace slag has been identified as a promising material for adsorbing and immobilizing phosphorus, as well as certain other dissolved and/or suspended contaminants such as arsenic and waterborne pathogens, from contaminated groundwaters and wastewaters (Blowes et al., 1996). Treatment of these contaminants requires the flow of water through a permeable bed, chamber or reactive zone containing the BOF slag. In use, Phosphex™ reactors (e.g., beds, chambers, EW cells) are operated in water-saturated modes and are designed to contain enough reactive BOF slag medium to remove phosphorus from stormwaters and wastewaters being passed through them for periods between 5 – 15 years, after which the medium must be removed and replaced. Spent medium can be landfilled, used as fertilizer or soil builder, or used as an aggregate or filler in civil engineering projects. BOF slag may used as is, or be the reactive medium in mixtures with other kinds of substrate materials such as sand, gravel, or limestone. Despite its advantages, the Phosphex™ technology has some disadvantages including a tendency of beds of BOF slag to cement up with tufa (calcium carbonate), the discharge of very high pH water from them, and the leaching of certain metals form the slags. In addition, if the slag material is not carefully prepared, free lime and other caustics occupying the spaces between slag particles will react with incoming ortho-phosphate forming apatites and other precipitates which can plug the beds. Laboratory and field-scale applications have demonstrated excellent treatment of arsenic, phosphate and pathogens (E. coli) in water using BOF slag (Baker et al., 1997; 1998, McRae et al., 1999; Blowes et al., 2000; Smyth et al., 2002). A patent (Blowes et al., 1996) has been acquired for this innovation in the name of the University of Waterloo. A technology based on this patent as applied to phosphorus removal from water has been protected under the trade-mark “Phosphex™”. Laboratory and field applications of BOF slag systems have been carried out and they have demonstrated excellent treatment and commercial potential for markets involving. The Phosphex™ may be particularly promising for: i) the removal of phosphate and pathogens associated with decentralized wastewater treatment as well as having applications for the treatment of stormwater runoff, agricultural drainage, and contaminated surface waters; and ii) treatment of dissolved metalloids and heavy metals, most notably arsenic, in groundwater or mine drainage water.

Bench-, pilot- and some field-scale testing of the Phosphex™ technology for wastewater treatment over the past decade have typically exhibited excellent contaminant removal over periods of a few months up to five years, but the same applications have also identified characteristics that potentially affect the long-term viability of such treatment systems.


E-16

Under a project funded by the NSERC Idea to Innovation (I2I) program, 11 samples of steel slags were obtained from ten steel mills in Ontario, Quebec, Indiana and Michigan (or from their associated distributors). These were evaluated with respect to their phosphorus removal potentials. The eleven samples included:

Stelco BOF slag (Hilton Works, Hamilton, ON) The Levy Corporation BOF slag (Portage, IN) The Levy Corporation BOF slag (Detroit, MI) Dofasco Inc. KOBM BOF slag (Hamilton, ON) Dofasco Inc. EAF slag (Hamilton, ON) Mittal Canada Inc./MultiServ screened BOF slag (formerly Ispat Sidbec Inc., Contrecoeur, QC) Mittal Canada Inc./MultiServ crushed BOF slag (formerly Ispat Sidbec Inc., Contrecoeur, QC) Gerdau Ameristeel EAF slag (Whitby, ON) Gerdau Ameristeel EAF slag fines (Whitby, ON) Gerdau AmeriSteel Corporation EAF slag (Cambridge, ON) Algoma Steel BOF slag (Sault Ste. Marie, ON)

Several tens of kilograms of slag material were supplied by the steel mills directly or by companies licensed to distribute slag. At UofW, one kg portions of the samples were sieved to establish grain-size distribution characteristics, and other portions were prepared for the laboratory batch and column tests. The laboratory batch and column tests to evaluate phosphorus removal from water were conducted using slag material coarser than 100 mesh (U.S. Standard Sieve; 0.01 in (0.25 mm) and finer than 8 mesh (0.125 in (3.175 mm)). In addition to the phosphorus removal tests, samples of each slag material were sent to SGS-Lakefield Laboratories for solid-phase chemical analyses. The analyses included major elements and trace metals and metalloids. All of the steel slags had similar chemical compositions, containing approximately 33 wt.% calcium oxide (CaO), 33 wt.% iron oxide (Fe2O3), 12 wt.% silica oxide (SiO2), 10 wt.% magnesium oxide (MgO) and 5 wt.% manganese oxide (MnO). Sulfur content was low and ranged between 0.08 and 0.2 wt.%. Batch tests were performed to assess the evolution of solution chemistry with time in the presence of reactive media within a glass flask. Each batch test involved the addition 750 gm of tap water spiked with phosphate into a flask containing approximately 50 g of a slag and silica sand mixture. Four tests were conducted for each slag. In two, the reactive mixture contained 2.5 g of slag and 47.5 g of silica sand, and in the other two, the mixture contained 5 g of slag and 45 g of silica sand. Slags were sieved to coarser than 50 mesh (U.S. Standard Sieve) and finer than 8 mesh. The flasks were agitated at room temperature on an orbital shaker and periodically sampled. The flasks were capped during shaking, but were open while samples were removed using a syringe. The tests were conducted over an eight-hour period. As many as 10 water samples were collected at time intervals that increased from 0.25 to 2 hour during the test. The analytical results indicated that concentrations of phosphorus decreased rapidly and pH increased as a function of time for all slag mixtures tested. Excellent phosphorus removal (99.8%) was achieved in the tests using Levy Detroit, Levy Portage, Dofasco EAF and Sault Ste Marie BOF using five gm slag mixtures. Phosphorus removal was


E-17

80% after 8 hours of testing using the Dofasco KOBM, Montreal screened and Montreal crushed BOF slags. In the batch test, the phosphorus removal performance of the Cambridge EAF and Whitby EAF slag was only ~40 %. The pH of the water was highest (11.5 to 12) in the tests involving the Levy Detroit, Levy Chicago and Algoma Sault Ste. Marie slag samples, and was lowest (~8 to 8.5) in the tests involving the Cambridge and Whitby slag materials. All 11 slag samples were evaluated in column tests to assess water-treatment characteristics under dynamic flow conditions. The barrels of the columns were 25.8 cm in length and 5 cm in diameter. The columns had an internal volume of approximately 0.5 L. Three shorter columns (length 15.8 cm) with 0.3 L internal volume were used for Whitby, Dofasco KOBM and Cambridge slag. The columns were operated in an upward-flow mode, and had two influent/effluent ports on both the top and basal plates of each column. The longer columns had eight lateral sampling ports spaced along the length of the column barrel and the shorter ones had four sampling ports. The column packing included 2 cm thick basal and upper filter layers containing washed Ottawa sand (20-30 Standard U.S. Mesh). The central portion of the column was filled with the reactive material (silica sand, pea gravel and slag mixture in dry form; 50 % slag by volume) in 150 mL increments. The pore volume (volume of water contained in each column when saturated with water) was estimated by comparing the total dry mass of each column to the water saturated mass. The pore volumes of the columns ranged from 100 mL for the short columns to as much as 200 mL for the long columns. Influent was tap water spiked with phosphate. Flow of source water through the columns had been maintained continuously from the start of testing (March 22 or April 15, 2005) for all columns except the two Stelco columns (July 2005). The volume of flow through each of the columns was monitored regularly. Flow rates were typically about 150 mL per day, therefore residence time of water in individual columns ranged from 0.5 to 1.5 days. The column-test results demonstrated excellent removal of phosphorus within the initial 10 cm in all BOF slag mixtures over the 6 to 10 months of testing. The phosphorus concentration decreased from an input value of ~ 20 mg/L (ranged between 16 and 24.5 mg/L P) in the input water to ~0.4 mg/L (98% removal) within ~8.5 cm travel through the Levy Detroit (LD), Levy Chicago (LC), Dofasco EAF (DE) and Stelco fine (ST) slags. In Sault Ste Marie (SN), Whitby “C” fine (WC), Cambridge (CA) and Montreal screened (MS) slags, more than 98 % of the phosphorous was removed within a zone 6.8 cm in length. The Montreal crushed (MC) slag achieved removal of more than 98 % of the phosphorus within a zone of 4 cm in length. Dofasco KOBM (DK) and Stelco coarse slag (STC) also exhibited good phosphorus removal characteristics, and had continued to remove >95 % of the phosphorus at the final sampling session. The concentration profiles of phosphorus as a function of distance in the columns showed a very gradual advance with increasing time of testing. The pH of the pore water in the columns increased from approximately 7 in the influent to between 11 and 12 in all columns with the exception of those containing Stelco fine (ST) and Stelco coarse (STC) slag in which pH was approximately 9.5 at the end of six months of testing. The residence times of water within the two Stelco slag columns were among the shortest (~0.5 days) of the columns tested.


E-18

A PhosphexTM (BOF slag) treatment chamber was installed to treat effluent from a septic system which used a recirculating sand filter at a single-family, lakeside household in North Bay, Ontario in the fall of 1999. This installation was part of a larger initiative by the City of North Bay, which oversaw installation, sampling and analyses, to demonstrate and compare the performance of several phosphorus removal technologies for on-site wastewater treatment systems. The PhosphexTM system was installed by an independent contractor with no direct participation of UofW. It was constructed of a flexible membrane liner in a wooden frame, and was designed to accommodate wastewater for a day under peak flow conditions. Following pre-treatment by the septic tank and sand filter, the water entering the PhosphexTM chamber had a pH value between 7 and 8, phosphorus concentrations between 5 and 10 mg/L (as PO4-P), and E-coli ranging from less than 250 to more than 100,000 CFU/mL. The monitoring confirmed increased pH (11 to12) of water in contact with the BOF slag and very low concentrations of phosphate (less than 0.02 mg/L as PO4

-P) and E-coli (less than 5 to 20 CFU/100 mL). The high-pH effluent water was discharged to the sub-surface through a tile bed. The pH of the effluent decreased in situ beneath the tile bed through geochemical interactions with the aquifer materials and interaction with CO2 in the vadose zone in the vicinity of the tile bed. Shallow groundwater monitoring adjacent to the tile bed indicated that the pH had declined to between 6 and 7. The PhosphexTM chamber operated maintenance free until the fall of 2004 when the influent and effluent pipe networks were de-scaled and flushed. Following further disruption of hydraulic performance of the chamber in the spring of 2005, the chamber was excavated and the slag material replaced in June 2005. Operation of the system was re-started in mid summer 2005, and the excellent phosphorus and E-coli removal characteristics were re-established. In late March 2006, overall system operation was terminated because of difficulty associated with pumping PhosphexTM effluent into the tile field. The North Bay trial achieved excellent treatment performance, but highlighted the need to incorporate design features and maintenance to ensure effective hydraulic performance. Precipitate formation observed within and down-stream of the PhosphexTM chamber was the primary concern. The precipitate formation was likely a consequence of CO2, and possibly organic carbon, being present in dissolved form in the water from the re-circulating sand filter, or from CO2 gas transport into the chamber, effluent reservoir or tile lines from the adjacent vadose zone. The Town of Richmond Hill initiated the Lake Wilcox Hypolimnetic Withdrawal Pilot Project in 2005 to evaluate the rehabilitation of phosphorus concentrations in an urban kettle lake. PhosphexTM was selected as a potential technology solution for pilot evaluation. The ultimate treatment goal was to re-circulate lake water through a PhosphexTM filter with a capacity of several thousand cubic meters. As the lake water passes through the PhosphexTM filter, phosphorus would be removed to low concentrations. After adjusting the pH to near-neutral levels, the water would then be returned to the lake. The final treatment system would need to handle several thousand cubic metres per day, and would be operate seasonally from the late spring to early fall. In order to evaluate the feasibility of using PhosphexTM in this lake treatment application, a field-scale pilot plant was initiated by the Town of Richmond Hill in the summer of 2005 under the management and oversight of their environmental consulting firm,


E-19

Gartner Lee. The system included three large columns in series with a combined internal volume of approximately 3 m3. The flow rate of the pilot ranged between 0.53 m3/ day to 1.51 m3/ day and the phosphate removal ranged from 96.8% to 99.3%. The pH of the PhosphexTM system was lowered using a CO2 gas-bubbling system which resulted in the effluent pH being decreased to between 7.0 and 9.64. The pilot system was subsequently run over the 2006 - 2007 summer seasons to incorporate some additional optimized design changes and to further generated a performance data set.

E.6 Phosphorus Removal in Wetlands

Phosphorus is present in wetlands in their soils/sediments, in microbes and other biota in them, and in living and dead wetland plants (which can contain from 1000 – 3000 mg P/kg). In acidic conditions, phosphorus may be fixed by aluminum and iron (if available), while under alkaline conditions, it may be fixed by calcium or magnesium (again, only if these species are available). Under reducing conditions (and most ordinary FWS and SSF CWS have anerobic micro-environments and zones), iron minerals in wetlands may be solubilized’ releasing phosphorus from co-precipitants (Kadlec & Knight, 1996, Kadlec & Wallace, 2008). Phosphorus from incoming stormwater or wastewater interacts strongly with wetland biota and wetland soils/sediments/substrates and is retained in various ways. Treatment wetlands, therefore, are capable of removing phosphorus from wastewaters and stormwaters on both short- and long-term bases by sorption, precipitation, biomass storage and cycling, and by burial in soils/sediments (Kadlec & Wallace, 2008). However, only limited amounts of phosphorus are present in living and dead plants, and harvesting to remove it is feasible only in very limited circumstances (e.g., floating aquatic plant systems, surface-vegetated versions of pond wetlands). Even in such cases, only a few percent of the incoming phosphorus can be removed by harvesting, even in lightly loaded CWs. In FWS CWs, phosphorus removal by sorption and biomass cycling are not sustainable as the system eventually saturates, but longer term, sustainable removal is possible by burial in sediments. In these CWs, 20 - 60% removal is possible. About the same level of phosphorus removal is possible in SSF CWs initially, but burial is not a factor, being replaced by the accretion of precipitates between the substrate particles, a situation that longer term, can lead to flow channeling and substrate plugging. The substrate medium may sorb phosphorus, especially initially, but the levels possible are strongly affected by its make up. Iron, aluminum, or calcium, and the available number of adsorption sites are factors. Some have claimed that phosphorus removal in SFF CWs does not follow the general first order models of the Rational Method (McCarey et al., 2004), but others have found, that at least with EWs, it does (Calder et al, 2006). Based on data from 90 SSF CWs, Kadlec & Knight (1996) developed the following correlation relating effluent phosphorus concentration (Co) to inlet concentration, Ci for values between 0.5 mg TP/L and 20 mg TP/L: (E.13)


E-20

These phosphorus removal mechanisms are finite and not sustainable and, in practice, the long term potential of SSF CWs per se for phosphorus removal is essentially zero (Kadlec and Wallace, 2008). (However, EW Systems can incorporate other kinds of cells such as alum sedimentation ponds that are able to remove phosphorus long term, and as is discussed in this Report, specific EW cells and systems to remove phosphorus are possible.) As was mentioned in Appendix E.6, various materials will sorb phosphorus from wastewaters and when these are used as all or part of substrate beds in SSF wetland cells, the result are EW cells. Shales (Drizo et al., 2000), lightweight aggregates (Zhu et al., 1997) and steel slags (IRAP, 1999) have been used in this manner. Calder et al., (2006) compared phosphorus sorption in three pilot-scale SSF wetland cells containing gravel, cement clinker and blast furnace slag. It was found that first order kinetics applied for the removals, with the slag having the best removal rates (kTP = 0.042 m/d) with the clinker having removal rates almost the same (kTP = 0.015 m/d) of the fresh quartz gravel (kTP = 0.017 m/d). (Literature values for areal rate constants for phosphorus in HSSF CWs average 0.003 m/d, [Kadlec & Knight, 1996], equivalent to a volumetric rate constant of 53 yr-1, See Table D.4.) The removal of high levels of phosphates from gypsum stack leachate (the by-product of the manufacture of phosphate fertilizers from phosphate rock) was evaluated (SESI, 1998, Higgins, 2000) using an indoor pilot-scale SSF EW system at the Alfred Pilot Unit (see Appendix D-10) with a BOF slag substrate. The following table summarizes the results for two wastewaters imported from the closed IMC phosphate manufacturing facility at Port Maitland, ON: a gypsum stack leachate, and a lime plant feedwater containing diluted leachate. Both were treated at a rate of 200 mL/min in a single SSF wetland cell (BOF substrate from Dofasco Steel in Hamilton, ON 0.8 m thick) with residence times of about one day. Table E-4: Pilot-Scale BOF Slag EW Results for High Phosphate Wastewaters (SESI,1998)

Leachate Lime Plant Feedwater

Average Influent PO4 Concentration (mg/L) 460 162

Average Effluent PO4 Concentration (mg/L) 0.7 0.6

Removal (%) 99.9 99.6

Indicated PFR Rate Constant kv (yr-1) 1,687 1,246

As may be seen, almost all of the phosphate is removed in a single pass. The first order, PFR volumetric plug flow phosphate rate constants of Table E.4 may be compared with average literature values (Kadlec & Knight, 1999 of 53 yr-1 for municipal wastewaters treated in ordinary SSF CWs. Test cell effluents were quite alkaline (pHs >11). Some hydroxyl apatite precipitate was observed to accumulate on slag particles near the test cell inlets, but this did not lead to clogging or interfere with operations as the slag was well weathered before use.


E-21

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