Case Study Using Fenton s Reagent Under a Performance- Based Remediation Contract Presented at JSEM 2006 Presented by: John Mieher, RG 7500 N Dreamy Draw Dr., Suite 2321 Phoenix, AZ 85020 602.266.2011 Mark MacEwan, PE 101 Marietta Street, Suite 2400 Atlanta, GA 30303 404.225.5514
Why Performance-Based Remediation? Performance-Based remediation is a contracting approach in which performance is judged against the desired outcome rather than the level of effort BEM and Tetra Tech partnered for this project and has functioned as an integral team in support of the Air Force mission to restore the DC34 ( Horse Pasture ) Site at Robins AFB, Georgia This Site represents one of largest single-site environmental PBC remediation projects for the Air Force ($8.7M)
PBC Goals of Project Achieve regulatory closure and no further action (NFA) status at each of the SWMUs for both soil and groundwater. Achieve NFA by 08 May 2009. Until NFA is realized, restoration activities will continue including ongoing operations, maintenance, and monitoring.
Site Description: Horse Pasture Site Location: Robins AFB, Warner Robins, Georgia Origin: Historical solid waste management unit (SMWU) Contaminants of Concern: TCE and degradation products, chlorobenzenes, acetone, and benzene Contaminant Distribution: Large, 7-acre plume Remedial Goals: Achieve milestones of PBC and ultimately achieve MCL cleanup levels for all groundwater wells by 2009. Regulatory Criteria: Compound: Acetone Benzene Chlorobenzene 1,3-Dichlorobenzene 1,4-Dichlorobenzene MCL (ppb): 1558 5 100 9.5 75 Compound: 1,2-DCA cis-1,2-dce PCE TCE VC MCL (ppb): 5 70 5 5 2
Modified Fenton s Reagent Rationale Large plume (7-acres) High oxygen content Very low natural oxidant demand Compatible contaminants of concern Beneficial use of confining clay layer Short contract duration Favorable bench-scale and pilot study results
Site Plan
Pilot Study Design Considerations Conceptual Site Model
Pilot Study Analytical Results Total Volatile Organic Compounds: Zone 1 Location DC34MW6 DC34MW6 DC34MW6 DC34MW6 Sampling Round Groundwater Baseline Post Treatment 1 Post Treatment 2 Post Treatment 3 Sampling Date Dec-04 Mar-05 Apr-05 Jun-05 Acetone 4 U 80 U 40 U 14 Benzene 10 13 12 5 Chlorobenzene 1,300 1,400 990 580 1,3-DCB 52 57 53 32 1,4-DCB 220 270 220 110 1,2-DCA 35 56 87 50 cis-1,2-dce 1,900 2,900 3,000 2,300 PCE 2 U 40 U 8.2 2 U TCE 7 11 10 U 6 Vinyl Chloride 340 410 330 360 Total VOCs 3864 5117 4700.2 3457 11% Reduction 6000 Total VOCs (ppb) 5000 4000 3000 2000 1000 3864 5117 4700.2 3457 0 Dec-04 Jan-05 Feb-05 Mar-05 Apr-05 May-05 Jun-05
Pilot Study Analytical Results (cont.) Total Volatile Organic Compounds: Zone 2 Location DC34MW28 DC34MW28 DC34MW28 DC34MW28 Sampling Groundwater Post Treatment Post Treatment Post Treatment Round Baseline 1 2 3 Sampling Date Dec-04 Mar-05 Apr-05 Jun-05 Acetone 22 100 110 76 Benzene 11 6 1.6 2 U Chlorobenzene 450 220 57 7 1,3-DCB 68 44 13 2 1,4-DCB 160 140 43 7 1,2-DCA 59 73 41 16 cis-1,2-dce 2,800 1,700 450 76 PCE 2 3 2.5 U 2 U TCE 660 430 120 22 Vinyl Chloride 160 40 7 0.86 J Total VOCs 4392 2756 842.6 206 95% Reduction Total VOCs (ppb) 4500 4000 4392 3500 3000 2500 2756 2000 1500 1000 500 842.6 206 0 Dec-04 Jan-05 Feb-05 Mar-05 Apr-05 May-05 Jun-05
Pilot Study Analytical Results (cont.) Total Volatile Organic Compounds: Zone 3 Location DC34MW19 DC34MW19 DC34MW19 DC34MW19 Sampling Round Groundwater Post Treatment Post Treatment Post Treatment Baseline 1 2 3 Sampling Date Dec-04 Mar-05 Apr-05 Jun-05 Acetone 4 U 4 U 3.8 2 U Benzene 240 1 0.9 0.2 J Chlorobenzene 1,200 2 2 U 3 1,3-DCB 16 1.8 1.8 1.6 J 1,4-DCB 13 2 U 2 U 0.4 J 1,2-DCA 2 U 2 U 2 U 2 U cis-1,2-dce 2 2 U 0.86 0.35 J PCE 2 U 2 U 0.46 2 U TCE 1.18 J 1 2 U 2 U Vinyl Chloride 2 0.44 2 U 2 U Total VOCs 1473 6.24 7.82 3 99.8% Reduction Total VOCs (ppb) 1600 1400 1200 1473 1000 800 600 400 200 6.24 7.82 3 0 Dec-04 Jan-05 Feb-05 Mar-05 Apr-05 May-05 Jun-05
Pilot Study Analytical Results (cont.) Total Volatile Organic Compounds: Zone 4 Location DC34MW10 DC34MW10 DC34MW10 DC34MW10 Sampling Round Groundwater Post Treatment Post Treatment Post Treatment Baseline 1 2 3 Sampling Date Dec-04 Mar-05 Apr-05 Jun-05 Acetone 4 U 40 U 23 31 Benzene 3 20 U 0.46 2 U Chlorobenzene 250 47 23 10 1,3-DCB 30 8 5 3 1,4-DCB 83 22 9 7 1,2-DCA 26 19 14 10 cis-1,2-dce 1,400 440 260 89 PCE 0.36 J 20 U 1 U 2 U TCE 190 58 18 13 Vinyl Chloride 110 19 7 5 Total VOCs 2092 613 359.46 168 92% Reduction 2500 Total VOCs (ppb) 2000 2092 1500 1000 500 613 0 359.46 168 Dec-04 Jan-05 Feb-05 Mar-05 Apr-05 May-05 Jun-05
Pilot Study Analytical Results (cont.) Total Volatile Organic Compounds: All Zones (Mass and Percent Reduction) All Zones All Zones All Zones All Zones Sampling Round Groundwater Baseline Post Treatment 1 Post Treatment 2 Post Treatment 3 Sampling Date May-03 Mar-05 Apr-05 Jun-05 Percent Reduction (%) 0 35.48 49.83 60.58 Mass Reduction (ug/l) 22727.28 11681.5 9084.2 7137.5 70 25000 Percent Reduction (%) 60 50 40 30 20 10 0 May-03 Mar-05 Apr-05 Jun-05 20000 15000 10000 5000 0 Mass Reduction (ug/l) Percent Reduction (%) Mass Reduction (ug/l)
Pilot Study Design Considerations Why ISOTEC? Chelated Iron Catalyst Low Concentration of Hydrogen Peroxide More Controlled Reaction
Pilot Study Design Considerations (cont.) Design Elements Tested PVC vs. Stainless Steel Well Screens Natural Sand Pack Radius of Influence Ratios (pounds reagent to pounds contaminant mass)
Groundwater Restoration of the Horse Pasture Site Summary Successful Pilot Study Analytical results >90% reductions three areas Decline in TZ1 area following contaminant desorption Last Robins site to meet RIP (first AF site to meet overall RIP Goal) Design elements successfully evaluated during pilot study Ready to ramp-up into full scale remediation Pilot study stoichiometry shows estimated two full rounds plus one to two partial rounds of ISCO
Full Scale Implementation Design Parameters 188 Wells Radius of Influence 20 in hot zone 25 in medium zone Anticipate 3 to 6 injection events using 12% peroxide solution
Full Scale Remedial Design Injection Well Configuration
Full-Scale Analytical Results Total Volatile Organic Compounds: All Zones (Mass and Percent Reduction) Sampling Round Groundwater Baseline Pilot Treatment 1 Pilot Treatment 2 Pilot Treatment 3 Full Scale Treatment 1 Full Scale Treatment 2 Sampling Date May-03 Mar-05 Apr-05 Jun-05 Oct-05 Jan-06 Percent Reduction (%) 0 35.48 49.83 60.58 62.39 68.49 Mass Reduction (ug/l) 22727.28 11681.5 9084.2 7137.5 6810.3 5704.5 Percent Reduction (%) 80 60 40 20 0 May-03 Mar-05 Apr-05 Jun-05 Oct-05 Jan-06 25000 20000 15000 10000 5000 0 Mass Reduction Percent Reduction (%) Mass Reduction (ug/l)
Site Plan
PBC Lessons Learned Soil Remediation Unknowns Buried drums encountered during soil remediation Change in base logistics/access gates Weather Impact of tropical storms Groundwater Remediation Insitu Chem-Ox success Partnering with Regulators Cleanup at source is most difficult
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