Advances in Persulfate ISCO Remediation. Scott Steffl FMC Corporation

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1 Advances in Persulfate ISCO Remediation Scott Steffl FMC Corporation

2 Agenda Activated Persulfate Overview New Activation Methods On Site Persulfate Measurement Kits

3 What is In-Situ Chemical Oxidation? The addition of oxidants into the subsurface to convert recalcitrant organic compounds to CO 2 and H 2 O or less toxic / more biodegradable intermediates Chemical Oxidation reduces contaminant mass through the oxidation process Suitable for saturated and/or vadose zone source and plume treatment

4 Common Chemical Oxidants used for Remediation Permanganate (MnO 4 ) low solubility of K salt not strong enough to destroy benzene (no radical mechanism) forms solid residues crust on DNAPL Hydrogen Peroxide (H 2 O 2 ) (Fenton s Reagent) very reactive (creates heat and off gas) so potential safety issues short half life so limited distribution radical mechanism Ozone (O 3 ) low solubility gas must be sparged short half life thus limited distribution Radical mechanism often an addition to AS/SVE so unclear if oxidation mechanism is responsible for contaminant removal Activated Persulfate (S 2 O 8 ) high solubility radical mechanism variable half live hence longevity can be adjusted from hours to months Safe to handle and inject

5 Klozur Persulfate Chemistry Activation Persulfate can produce radicals which are powerful and kinetically fast, however activation is required fast, Persulfate however can produce radicals which are powerful and kinetically Engineered site activation methods is required are designed based on: specific contaminant(s) their nature and distribution site lithology S 2 O activator SO4 - + (SO4 - or SO -2 4 ) Heat Iron H 2 O 2 High ph Purchase of FMC s Klozur Persulfate includes rights to practice the inventions covered by the patents in the purchase price of the product

6 Activated Persulfate Effective on a broad range of organic contaminants Chlorinated Solvents PCE, TCE, DCE TCA, DCA Vinyl chloride Carbon tetrachloride Chloroform Chloroethane Chloromethane Dichloropropane Trichloropropane Methylene chloride Others Carbon disulfide PFOS / PFOA Aniline PVA TNT / DNT TPH BTEX GRO DRO ORO creosote Oxygenates MTBE TBA Freons Chlorobenzenes Chlorobenzene Dichlorobenzene trichlorobenzene Phenols phenol Pentachlorophenol nitrophenol PAHs Anthracene Benzopyrene Styrene Naphthalene Pyrene Chrysene trimethylbenzene Pesticides DDT Chlordane Heptachlor Lindane Toxaphene MCPA Bromoxynil

7 Iron Lactate New Activator Iron chelates have been shown to keep iron soluble across a neutral ph range Fe-Citrate and Fe-EDTA have been used to activate persulfate FMC researched iron lactate as an alternative activator

8 October 19, 2013 Iron Lactate activated persulfate TCE (ppm) hours Control (no persulfate) persulfate only Fe EDTA Fe Lactate Benzene (ppm) hours Control (no persulfate) persulfate only Fe EDTA Fe Lactate Lab results : 5 g/litre persulfate and 90 mg/litre iron

9 Ascorbic Acid New Activator Activation by direct oxidation of ascorbic acid S 2 O H 2 A SO A - + SO H +

10 October 19, 2013 Activation Efficiency Ascorbic Acid Benzene (ppm) Days TCE (ppm) Molar ratio Ascorbic Acid ,6 1,4 1,2 1 0,8 0,6 0,4 0,2 0-0, Days Molar ratio Ascorbic Acid

11 Persulfate Field Measurements Groundwater Measurement Primary Activator S 2 O -2 8 SO 4 - SO4-2 Contaminant Persulfate Activator Secondary sulfate ORP DO ph conductivity (chloride)

12 Klozur Persulfate Field Test Kits Klozur Persulfate Activator Chemistries Primary Titration Chemistry Kit K High ph Heat Permanganate back-titration of ferrous ammonium sulfate Kit C Chelated iron Ceric sulfate back-titration of ferrous ammonium sulfate Measurement Range: Accuracy: 1 g / L to 100 g / L Shelf Life: one year Storage: cool, dry conditions Operating Ranges: Water temperature 5 50 C ph 12 Fe(II) mg/l Range 1 50 g / L +/- 1 g / L Range g / L +/- 2 g / L

13 Summary Activated persulfate can treat a broad range of organic contaminants New activation methods have been developed to improve activator efficiency and address prior limitations Klozur Field Test Kit have been developed to allow for direct measurement of persulfate in groundwater in the field