Ian Ross Ph.D. Mike Mueller & Philip Bock Ph.D. Aquaconsoil, Barcelona April 16, 2013

Transcription

1 Novel Activation Methods for Persulfate Oxidation: Cement, Lime and Calcium Peroxide Ian Ross Ph.D. Mike Mueller & Philip Bock Ph.D. Aquaconsoil, Barcelona April 16, 2013

2 Introduction to Activated Persulfate Oxidation Potentials In situ chemical oxidation ISCO with activated persulfate volts F OH 2.7 SO O S 2 O H 2 O MnO HClO 1.6 Cl ClO ClO

3 Chemistry and Stoichiometry However, persulfate anion kinetics are generally too slow for most contaminants. As a result, you must activate persulfate to form the sulfate radical. Activated Persulfate S 2 O activator SO4 - + (SO4 - or SO 4-2 ) Sulfate-free radical: SO e - SO 4-2 Activation produces a radical which is more powerful and kinetically fast proper activation method is based on contaminant, site lithology, and hydrogeology FMC always recommends using an activator

4 Klozur Activator Chemistry Primary Methods to Activate Klozur Persulfate Heat S 2 O heat 2 SO 4 Fast kinetics C Hydrogen Peroxide S 2 O H 2 O 2 2SO 4 + 2OH Fast kinetics ~ 0.7 lb H 2 O 2 / lb persulfate (46.2 gal 17.5% / 100 lb persulfate) Metal Chelates M +2 High ph [FeEDTA] Chelant Target Contaminants: Chlorinated ethenes, BTEX, MTBE, PAHs Typical use at gas stations and dry cleaners Moderately fast kinetics Target ph Alkalinity aids in desorption kinetics Forms super oxide which aids in dechlorination

5 Novel activation methods Cement with lime activation Activation with calcium peroxide

6 Combining activation with stabilization - cement activation Combination of Portland cement and lime as an activator package Heat generation from the pozzolonic cement reactions Soil stabilization and solidification

7 Cement Activation AT Turtle Bayou Turtle Bayou Far West Road Area Remediation Summer Fall 2008 Waste disposal believed to have started in the late 1960s Liquid waste dumped in unlined pits possibly tilled. Liquid waste applied to Frontier Park Road for dust suppression. Disposal company contracted to incinerate industrial fluids was diverting waste to site.

8 Cement Activation at Turtle Bayou List of contaminants fo concern: Acetone Naphthalene Styrene tert-butyl alcohol 1,1,2-Trichloroethane Trichloroethene Vinyl chloride 1,1-Dichloroethane 1,1-Dichloroethene 1,2-Dichloroethane 1,2-Dichloropropane cis-1,2-dichloroethene trans-1,2-dichloroethene Benzene Toluene Ethylbenzene Xylene (total)

9 Cement activation at Turtle Bayou Treatment Area Layout 4,800 ft 2 to 25 depth Augur drill locations Application of 760,000 lbs of persulfate April 30, 2013

10 Cement activation at Turtle Bayou Chemical handling and mixing system Large augur soil blending system

11 Cement activation at Turtle Bayou

12 Cement Activation at Turtle Bayou The remediation goal of 80% mass destruction was met. (84% based on confirmatory soil borings conducted 30 days after completion of the ISCO borings.) Based on the confirmation analysis, remaining acetone, tert-butyl alcohol, 1,1-dichloroethane and 1,2-dichloroethane concentrations were 1 to 2 orders of magnitude higher than any of the other COCs. Four data points skewed % mass destruction downward: Acetone and TBA at in CB-01. 1,1-DCA at in CB-03. TBA at 0-5 in CB-05. The four data points reduced mass destruction from 97% to 84%.

13 Soil Mixing with Lime Activation Lime is a good choice for persulfate activation when soil blending / mixing Inexpensive Activation through alkaline conditions Produces heat upon hydration (for additional persulfate activation) Reduces groundwater sulfate concentrations through precipitation of gypsum (calcium sulfate) But.. Lime can provide mis-leading results as it can encapsulate contaminant when not coupled with persulfate!

14 % reduction Soil Mixing with Lime Effect of Lime and Persulfate on Contaminant Destruction in Sediment PCB PAH Initial contaminant concentrations: PCB 7800 mg/kg PAH 7700 mg/kg

15 In Situ Chemical Oxidation of Chlorobenzene using Klozur Activated Persulfate Design Objective; maximize in situ destruction of COC in a single round of intensive treatment continuous flight auger rigs 7,317 m2 (all 5 Hotspots) treated Sept 07 Feb 08 - most impacted areas in Hotspots were treated twice Persulfate injection concentrations; 20 and 40% wt/wt (mostly 40% wt/wt) Lime activation resulted in enhanced mobilization of COC from sorbed and NAPL phases Estimated that 11,304 kg of COC s were oxidized in the soil phase - calculated that 189 kg of COC was oxidized in dissolved phase Concentrations of chlorobenzene and dichlorobenzene reduced at least ten fold since completion of the ISCO treatment Thornton, England Area B Area D Latest samples; all COC s are significantly below EQS (Envl Quality Std s) June 2008; Site closed acceptance letter by The Environment Agency 2008 Brownfield Briefing Remediation Innovative Award (bbria) for Best Conceptual Design Area A Area C Area E

16 Calcium Peroxide Activator Chemistry Coupling ISCO + Bioprocesses Klozur Persulfate ISCO for 2 3 months self-activating high ph persulfate S2O8-2 SO4 -, OH - residual sulfate to stimulate anaerobic bioremediation + Klozur CR PermeOx Plus slow release of oxygen for up to one year stimulate aerobic bioremediation CaO2 + 2 H2O H2O2 + Ca(OH)2 2 H2O2 O2 + 2 H2O

17 Klozur CR Combined Remedy Klozur CR impact across the site: Injection well Injection of Klozur CR high level chemical oxidation elevated dissolved oxygen natural organic extraction Down gradient dissolved O 2 sulfate molecular organic fragments groundwater flow monitoring well Contaminant plume

18 Impact on Aerobes Field Study West Central Alberta diesel and gasoline plume site Contaminants: BTEX, fuel constituents F1 and F2 Lithology: alternating layers of siltstone / mudstone and sandstone Application: 1600 lbs of Klozur CR Data courtesy of: Jim Studer, InfraSUR Portion of plume with dissolved phase Portion of plume with diesel / gas NAPL

19 Apr-07 May-07 Jun-07 Jul-07 Aug-07 Sep-07 Oct-07 Apr-07 May-07 Jun-07 Jul-07 Aug-07 Sep-07 Oct-07 Apr-11 May-11 Jun-11 Jul-11 Aug-11 Sep-11 Oct-11 Apr-07 May-07 Jun-07 Jul-07 Aug-07 Sep-07 Oct-07 Impact on Aerobes Field Study INJ92A Performance Data - Hydrocarbons INJ93A Performance Data - Hydrocarbons % Klozur OBC Injection % Klozur OBC Inj ection 0 0 Benzene (mg/l)x100 Toluene (mg/l)x100 Ethylbenzene (mg/l)x100 Xylene (mg/l)x100 F1 (mg/l) F2 (mg/l) Benzene (mg/l)x100 Toluene (mg/l)x100 Ethylbenzene (mg/l)x100 Xylene (mg/l)x100 F1 (mg/l) F2 (mg/l) INJ94A Performance Data - Hydrocarbons MW32 Performance Data - Hydrocarbons % Klozur OBC Inj ection OBC & PoxP Inj ection Benzene (mg/l)x100 Toluene (mg/l)x100 Ethylbenzene (mg/l)x100 Xylene (mg/l)x100 F1 (mg/l) F2 (mg/l) Benzene (mg/l)x100 Toluene (mg/l)x100 Ethylbenzene (mg/l)x100 Xylene (mg/l)x100 F1 (mg/l) F2 (mg/l)

20 Impact on Aerobes Field Study Biological Assay Bio-Traps deployed with C 13 -labelled benzene substrate Results Bio-Trap from Microbial Insights Near complete reductions of contaminants in all pilot monitoring wells microorganism populations reduced initially, but rebounded quickly (both aerobic and anaerobic) benzene utilization observed post ISCO application ( mg / day)

21 Impact on Anaerobes Sulfate Reducing Bacteria (SRBs) W. Michigan Lab Study Prof. Dan Cassidy % reductions from control contaminated sediments from Kalamazoo River Dose MeHg 1 (%) PCB 2 (%) PAH 2 (%) study incorporated 3 dosages 4 g / kg sediment 10 g / kg sediment 20 g / kg sediment Dose 1 > Dose 2 > Dose 3 > time= 5-10 days Stirred tank reactor 2 time= 4-8 weeks

22 log MPN/g soil Impact on Anaerobes SRBs MPN of Sulfate Reducing Bacteria (SRB) Time (weeks) Control Dose 1 Dose 2 Dose 3 SRB survive high doses of persulfate

23 Sulfide Conc. (mg/l as S) Impact on Anaerobes SRBs Sulfide Production Time (weeks) Control Dose 1 Dose 2 Dose 3

24 Impact on Anaerobes SRBs HgS formation after 30 weeks Dose [HgS] (μg/kg)* % total Hg Control Dose Dose Dose *[HgS]=203 μg/kg if all Hg precipitated as cinnabar.

25 Summary Activated persulfate can treat a wide range of contaminants Cement activation can be an effective approach to activate persulfate in a soil blending application Calcium peroxide can couple persulfate ISCO with subsequent bio-process

26 Questions? Ian Ross, PhD FMC Corporation Our remediation chemistries have had a positive impact in the communities in which we live and do business. We believe sustainability demands the use of the right chemistry - building on sustainable innovation, operations, and business practices - as we seek to grow and improve the quality of people s lives everywhere. The use of hydropower in our manufacturing process contributes significantly to our sustainability initiative; having one of the lowest carbon footprints in the environmental market for chemical remediation technologies.