Presentation on theme: "IN SITU TREATMENT WITH HYDROGEN PEROXIDE Bruce Leavitt PE PG, Consulting Hydrogeologist Washington, Pennsylvania Prepared in conjunction with West Virginia."— Presentation transcript:
IN SITU TREATMENT WITH HYDROGEN PEROXIDE Bruce Leavitt PE PG, Consulting Hydrogeologist Washington, Pennsylvania Prepared in conjunction with West Virginia University under a grant from the Office of Surface Mining Applied Science Research Program
Hydrogen Peroxide: Net alkaline mine drainage Rapidly oxidize ferrous iron in mine drainage 2 Fe 2+ + H 2 O OH ¯ 2 Fe(OH) 3 Is used at some AMD treatment facilities. Freezing point -33 C° (35 % solution) Density (35 % solution)
T & T Mine Complex
Mine Portal Discharge
H-Flume & Sample Pipe
T & T Water Quality
Two Inch Well with Sampling Well Discharge
Five Inch Well Casing ya gotta love hydrostatic pressure
Hydrogen Peroxide Storage
Variable Peristaltic Pump
Effect of Peroxide Addition DateTimepHDOORPAlk 8/18/200910: /19/20098: Peroxide on 8/18/09 11:10 metering pump
Bench Tests 10 liter continuously stirred Dilute 35% H to 11.67% Monitor pH, ORP, & DO Micro pipette ( g/dose) Aeration tests with and without peroxide Settling tests
T & T #2 Mine Water
Settling of Peroxide Treated Mine Water 50 min. 100 min. 24 hours
Travel Time Ruthbelle to main discharge 32 hours at 700 to 750 gpm, Coastal Coal dye test. Coastal well to sampling well: 87 minutes first arrival, 212 minutes complete reaction.
Peroxide Dosing Rate
Aeration with pH Monitoring
Carbon Dioxide Removal
Determination of Complete Oxidation In Situ
ORP at the Discharge
Percent Ferrous Iron in the Mine Discharge
Dissolved Iron at the Discharge
Flow in the Mine Entry Mine Discharge 175 gpm. Calculated flow in the test entry 43 gpm. Calculated flow is 24.6% of total flow. Mined area is about 33% of total mined area. Flow unlikely in up dip entry. Possibilities: Non-uniform recharge, Sludge disposal, Flow in up dip entry.
Estimation of Ruthbelle Water Quality LivengoodT&T DischargeRuthbelle est. Flow pH Acidity Dissolved Fe Ferrous Fe Dissolved Al Dissolved Mn Dissolved Ca Dissolved Mg Sulfate
Cost of Treatment mg/L Ferrous required 6.2 to 6.32 mL/min of 35% H 2 O mL / 1000 gal. 600 gal H 2 O 2 = $3,400 $0.22 per 1000 gal treated. $ per mg/L/1000 gal.
Conclusions In Situ oxidation of ferrous iron using hydrogen peroxide has been demonstrated. The reaction is rapid and proportional to dose. Either pH, ORP, or both may be used to determine the completion of the oxidation process so that over treatment does not occur. Hydrogen Peroxide addition does not affect the amount of carbon dioxide dissolved in the mine water.
Conclusions continued Hydrogen peroxide can be used to determine the volume of flow in an entry. Injection of hydrogen peroxide into a point of concentrated flow was deemed essential. The chemical cost of Hydrogen Peroxide treatment has been calculated to be $ per mg/l ferrous per 1000 gallons. The estimated capital cost for a single site is $36,000 although this number will vary with site specific conditions.
Recomendations The potential addition of alkalinity to the sludge disposal water in T&T #3 should be investigated. In Situ settlement of iron should be achievable in T&T #2 if the location of the injection well is located further in-by the test location. Pre-aeration may reduce ammonia requirement.