Utilization of Steel Furnace Slag in Environmental Remediation

Transcription

1 Utilization of Steel Furnace Slag in Environmental Remediation JOHN J YZENAS JR / DIRECTOR TECHNICAL SERVICES KELLY COOK / LAB SUPERVISOR EDW. C. LEVY CO. DEARBORN, MICHIGAN STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 1

2 Slag is not Just Slag Foundry Slag Manganese Zinc Chrome Radio-active ETC. ETC. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 2

3 Physical Characterization Physical Properties Gradation Moisture Specific Gravity and Absorption Unit Weight Expansion / Disruption Permeability STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 3

4 Chemical Characterization Chemical Properties ph Chemical Analysis Target Analyte List (TAL - Metals) Toxicity Characteristic Leachate Procedure (TCLP) X-Ray Refraction (XRF) - oxides X-Ray Diffraction (XRD) - mineralogy Calcium Carbonate Equivalency (CCE) Free Lime STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 4

5 Oxides versus Mineralogy Typical Oxide Analysis SiO % Al 2 O % CaO 20-50% Major primary mineral constituents larnite, beta-dicalcium-silicate srebrodolskite, calcium-iron-oxide brownmillerite, calcium-aluminium-ironoxide Molecular and structural formula beta-ca2sio4 Ca2Fe2O5 Ca 2 AlFeO5 MgO 5-20% spinel Me2+Me3+2O4 MnO 0-8% FeO 10-40% wuestite, solid solution of iron(ii)-oxide with MgO and MnO (Fe1-x-y,Mgx,Mny)Oz S 0-1% gehlenite, calcium-aluminium-silicate Ca 2 Al 2 SiO 7 bredigite, calcium-magnesium-silicate Ca 14 Mg 2 Si 8 O 32 STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 5

6 Safety When Correctly Characterized Properly Processed steel slags are found to be safe and non-hazardous. TCLP Toxicity Characteristic Leachate Procedure Total Metals Human Risk Assessment 2011 STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 6

7 Manufactured Product Chemical Make-up Particle size Permeability Sorption Capacity STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 7

8 Environmental Remediation In many cases the leaching of chemicals into the environment creates massive issues: Fish Kills Destroying Vegetation Contaminating Drinking Water Health Hazards STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 8

9 Acid Mine Drainage (AMD) During Mining, pyrite is exposed to oxygen. Ground water seeps into the mine. Oxygen, water and pyrite react to form sulfuric acid and in turn dissolve metals from the rocks. Water drains out of the mine. Dissolved metals react with oxygen and fall out of solution into the stream water, turning a bright color. Aquatic animals and plants are killed by the drainage. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 9

10 AMD Remediation Active Treatment-Neutralization by Addition of Lime/Limestone Install Treatment Plant (High Cost) Passive Treatment - Utilize Naturally Occurring Biological and Geochemical Processes Steel Slag Utilization High Calcium Content Slag s ph is very high (>11%) Produces a High Alkaline Environment to Balance the acidic drainage. (ph > 7) STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 10

11 Metals Remediation Benefits of Steel Slag Crystalline phases of Fe, Mg, Ca and Silicates E.g. FeO, Fe 3 O 4, Ca 2 SiO 4, etc. Free Lime and Portlandite Dissolution drives ph & alkalinity Large Surface Area Potential for the sorption of Metals (e.g. Pb, Zn) and Oxyanions (As, Se) STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 11

12 Permeable Reactive Barrier (PRB) PRB s consist of a trench filled with reactive materials placed in the pathway of contaminated groundwater. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 12

13 University of Waterloo East Chicago, In mg/l As plume with neutral ph. Mainly As III 2 Parallel Barriers (3 meters apart) 500 meters long 11 meters deep 0.6m 5- years Removed Arsenic to <0.01 mg/l Slag ph reduced STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 13

14 Phosphorous Run-Off Leading Cause Waste Water / Agriculture / Animal Lots Non-Point Run-off: Agricultural, urban/residential Point Run-off: Waste Water 37% of Large River Delta, Coastal Waters are in Poor overall Condition (US EPA) Reducing P loads from soils to surface waters is necessary for resolving Eutrophication. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 14

15 Lake Erie Loading in 2003 was ~2448 tons of P Michigan Sea Grant STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 15

16 Western Lake Erie Watersheds 7.1 Million Acres: 70 % in Ohio 12% in Indiana 18% Michigan About 76% Cropland: 3/4 Corn & Soybeans Maumee Drains 2/3rds Area STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 16

17 River Raisin Watershed 1, 072 square miles Population: 178,577 (2010) Five Counties: Lenawee Monroe Washtenaw Jackson Hillsdale 22 Mainstream Dams 38 Tributary Dams 65% Agriculture 11% Urban 8% Wetland 7% Forest 7%Grassland STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 17

18 Erosion Control Erosion control and buffers are not always the solution to dissolved P. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 18

19 Major Source? Average Annual Export From the Maumee WS is 1.1 Pounds of P per acre as measured through the Heidelberg Gage at Waterville. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 19

20 Research USDA Soil Erosion Lab West Lafayette, IN STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 20

21 Remediation Design STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 21

22 Why Steel Slag? Early studies in Japan Yamada et.al Steel Slags Basic Oxygen Furnace (BOF) Electric Arc Furnace (EAF) Can reduce P by about 75 90% Photo System treats 150 Acres. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 22

23 Goals European Framework Directive [2000/60/EEC] defines clean water as <2 mg P / L. Laboratory tests indicate that slag can provide high phosphate adsorption (1 50 g P/kg slag). Positive effects are attributed to Ca 2+ -release and/or Fe, Al in solid. The use of steel slag as filter materials to remove P from agricultural run-off, wastewater and animal manure by: The design, construction, optimisation of slag filter systems on a pilot scale (in Michigan and Ohio) The examination of spent slag as potential (P-)fertilizer The assessment of the economic aspects of field treatment. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 23

24 Determination of P Sorption How much P will it hold? How fast will the P bind? Which is the best method? Methods: Batch Test Flow Trough Langmuir equation STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 24

25 Batch Test Suitable as an index for comparing the P sorption capacity of various PSM s. Values should not be used in the design of a P removal structure. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 25

26 Flow Through Mariotte Bottle Flow through cell Filter PSM Allows the use of low inflow P concentrations that are representative of drainage and wastewater dissolved concentrations. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 26

27 Langmuir Equation The batch isotherm results are used to develop the Langmuir model which tends to overestimate and underestimate P sorption in in various PSM s, relative to flow-through. A current study indicated that the Langmuir equation has poorly predicted P sorption in a pilot scale pond filter while the flow-through model produced reasonable estimates. Results suggest that flow-through methodology is necessary for estimating P sorption in the context of landscape P filters. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 27

28 Design Components Hydraulic Conductivity P Sorption ph Total Ca, Al, Fe Amorphous Al, Fe Buffer ph Index Mean particle size Bulk Density Porosity and Particle Density Saturated Hydraulic Density Total Metals Concentration Metals Solubility SPLP STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 28

29 Phosphorous Removal Efficiency by Size European Trials BOF-CA EAF-CA BOF-Fine EAF-Fine BOF +Sand EAF +Sand Mass "P" Inlet [g/kg slag] Mass "P" Retained Removal Efficiency [g/kg slag] [%] STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 29

30 Slag Volume Expected Outlet Concentration (mgp/l) BOF Outlet concentration LIfespan 0 0 0,0 0,5 1,0 1,5 2,0 2,5 Slag volume m3/pe Lifespan (year) Expected Outlet Concentration (mgp/l) EAF Outlet concentration LIfespan 0 0 0,0 0,5 1,0 1,5 2,0 2,5 Slag volume m3/pe Expected P concentration in the outlet and lifespan of filter systems as function of slag volume per PE Lifespan (year) STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 30

31 Observations BOF- and EAF slag are capable to remove significant amounts of P from wastewater, even on long terms. Attainment of the target value of 2 mg P/liter in the outlet is a realistic target. Removal efficiency is improved by longer contact time of wastewater and slag, higher ph (ph 8,5 instead of 8,0), higher temperature (summer instead of winter), improved design of filter systems (small, uniform grain size, increased CaO / FeO concentration in slag) STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 31

32 Waste Water New Zealand Township of Waiuku Installed in 1993 and handles up to 3000m³ a day of treated effluent from the settling ponds. Department of Conservation Headquarters in the Waipoua Forest Septic Systems STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 32

33 University of Waterloo Sewage Treatment System in Banff National Park, Canada Utilizes steel slag to chemically bind the residual phosphorus. Beneficial side effect, a measureable drop in e-coli and coliform bacteria. STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 33

34 Storm Sewers / Run-Off Storm Sewers Urban / Residential STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 34

35 Agricultural Fertilizer Run-Off Surface Drain Tile STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 35

36 Gabion Concept Drizo STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 36

37 Animal Lots Manure Cows Chicken Pigs Processing / Handling is costly Ship to treatment Spread on Field Excess Nutrients (Phosphorous, etc.) Artificial Wetlands Spread on Field STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 37

38 Acknowledgements Chad Penn USDA ARS Stan Livingston USDA ARS Aleksandra Drizo PhosphoReduc University of Waterloo STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 38

39 Thank You Questions? STEEL FURNACE SLAG IN ENVIRONMENTAL REMEDIATION 39