NanoFe. Supported Zero-Valent Nanoiron. An Innovative Remediation Technology for Soils and Groundwater. PARS Environmental Inc.

Transcription

1 NanoFe Supported Zero-Valent Nanoiron An Innovative Remediation Technology for Soils and Groundwater PARS Environmental Inc. H.S. Gill Ph.D. Tel:

2 Introduction NanoFe will remediate recalcitrant contaminants in soils and groundwater Sub-micron (<10-6 m) particles of Fe 0 with a noble metal catalyst Based on proven redox processes Very flexible and destroys contaminants rapidly in-situ or ex-situ 2

3 Treatable by NanoFe Technology Contaminants: Halogenated aliphatics (PCE, TCE, DCEs, VC) Halogenated aromatics PCBs Halogenated herbicides & pesticides Nitroaromatics Metals (e.g. Cr +6 ) Geologic Conditions: Sand Silt Fractured rock Landfills Fill materials Sediments 3

4 Clm Clm Cln Cln Applications of NanoFe Technology RCl n R H n + n Cl - [H] R Cl n e - ~ 0.1 µm Reductant ( Fe, Zn, Al ) Me n+ Catalyst ( Pd, Ag, Ni ) Ground Water Soil/Sediment Drinking Water Pump Monitoring Well Cl Biphenyl THMs Wast e Injection Well Metal Particle Suspension Control Volume Nanoscale Fe Particles Deposition Attachment Nano-particles SOIL PARTICLE PCBs Nanoparticle Embedded Granular Activated Carbon In Situ Reactive Zone Groundwater Flow Transport Detachment 1. Smaller than bacteria 2. Penetrate intraparticle pores 3. Reduce highly chlorinated compounds 4. Faster desorption due to dechlorination 5. Faster biodegradation Methane Treatment of Chlorinated Solvents Bioavailability Enhancement (PCBs and Chlorobenzenes) Trihalomethane (THM) Reduction 4

5 Technology Overview Iron is an effective reductant Based on proven redox process; contaminant serves as the electron acceptor Fe 0 + R-Cl + H + Fe +2 + R-H + Cl - Cr(VI) Cr(III) Major process variables: Fe 0 surface area (smaller particles are better) Presence of a noble metal catalyst NanoFe can be injected by gravity or under pressure 5

6 NanoFe Dehalogenation Schematic C 2 Cl 4 C 2 H 6 + Cl - e- Fe 2+, Zn2+ Base metal - Electron donor ~100 nm Noble Metals: - forms galvanic cells - catalyze hydrogenation Base Metal (Fe, Zn, Al, etc) Noble Metal (Pd, Pt, Ag, Ni, etc) 6

7 Treatment of Chromium Ore Processing Residue (COPR) Cr(VI) is reduced by nano iron to Cr(III) and immobilized as Cr(OH) 3 Nano iron particles further prevent Cr oxidation and leaching by Forming galvanic cells on the COPR surface, and Consuming oxidant such as oxygen 7

8 NanoFe Production Process Step I Preparation of Fe 0 particles 2FeCl. 6H 2 O + 6NaBH 4 2Fe 0 + 6B(OH) 3 + 6NaCl Step II Deposit catalytic metal on surface 2Me +n + nfe 0 nfe Me 0 Where Me is generally Pd or Pt 8

9 A Case Study A 27-acre NJ manufacturing site Continuous production since 1930s Major soil and groundwater contaminants include TCE, CCl 4, and BTEX >$1.0 million has been spent on natural attenuation Active remedy required 9

10 The Field Test Set Up Test area MW-15 and three pairs of nested piezometers 5, 10, & 15 feet downgradient of MW-15. Two 165 gal tanks Recirculation to storage tank Goal = Gravity Feed! 10

11 Schematic of Field Test Set-up injection and transport of nanoparticles in aquifers Pump Metal Particle Suspension Monitoring Well Waste Injection Well Nanoscale Metal Particle Deposition Attachment Flow Detachment In Situ Reactive Zone Transport Control Volume Aquifer Solids 11

12 The Secret Weapon NanoFe! NanoFe = Fe 0 with a Pd 0 coating (catalyst) 1.7 lbs used in Phase I, 3.75 lbs used in Phase II Slurried in 130 gal of GW 12

13 Gravity Injection a Success! NanoFe easily gravity-fed A conc. of 1 g/l minimizes plugging K = 2x10-1 cm/s Lower K formations may require pressure 13

14 NanoFe Process a Success! A total of 5 lbs NanoFe injected TCE levels reduced up to 95% Process is simple, low cost, & portable 14

15 Cost Comparison Remedial Approach Estimated Cost 1. Pump and Treat 2. Reactive Barrier 3. NanoFe $4,160,000 $2,200,000 $ 450,000 15

16 NanoFe Technology Treats dissolved plume and source area(s) No depth limitations Highly reactive rapid degradation & no toxic intermediates Portable low capital + O&M costs Easily injected, NanoFe flows with groundwater Low NanoFe /contaminant ratios required 16

17 NanoFe Recent Projects Site Location Principal Contaminants Manufacturing Plant Trenton, New Jersey TCE, cis-dce, Vinyl Chloride Former Electronics Manufacturing Plant Titusville, Pennsylvania PCE, TCE, cis-dce Plating Facility / Superfund Site Franklin Square, New York PCE, TCE, 1,1,1-TCA, Cr (VI) DOD Facility Lakehurst - 1, New Jersey TCE, cis-dce, Vinyl Chloride DOD Facility Lakehurst- 2&3, New Jersey TCE, cis-dce, Vinyl Chloride Former Electrical Distribution Facility New Brunswick, New Jersey TCE, 1,1,1-TCA, 1,1-DCA, 1,1-DCE Manufacturing Plant Newfield, New Jersey TCE, cis-dce, Cr (VI) Landfill Site Hamilton, New Jersey 1,1,1-TCA, 1,1-DCA, 1,1-DCE, Pb, Ni Chromium Ore Landfill Kearny, New Jersey Cr (VI) Former Chemical Manufacturing Plant Salem, Ohio TCE, cis-dce, Vinyl Chloride DOD Facility Dover, New Jersey CT, CF, TCE, PCE, 1,1-DCE DOD Facility Aberdeen, Maryland 1,1,2,2-TeCA, 1,1,1-TCA, TCE Chromium Ore Landfill Jersey City, New Jersey Cr (VI) DOD Facility Jacksonville - 1&2, Florida TCE, cis-dce, Vinyl Chloride 17