Case Study Using Fenton s Reagent Under a Performance- Based Remediation Contract

Transcription

1 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 Mark MacEwan, PE 101 Marietta Street, Suite 2400 Atlanta, GA

2 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)

3 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 Until NFA is realized, restoration activities will continue including ongoing operations, maintenance, and monitoring.

4 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 Regulatory Criteria: Compound: Acetone Benzene Chlorobenzene 1,3-Dichlorobenzene 1,4-Dichlorobenzene MCL (ppb): Compound: 1,2-DCA cis-1,2-dce PCE TCE VC MCL (ppb):

5 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

6 Site Plan

7 Pilot Study Design Considerations Conceptual Site Model

8 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 Chlorobenzene 1,300 1, ,3-DCB ,4-DCB ,2-DCA cis-1,2-dce 1,900 2,900 3,000 2,300 PCE 2 U 40 U U TCE U 6 Vinyl Chloride Total VOCs % Reduction 6000 Total VOCs (ppb) Dec-04 Jan-05 Feb-05 Mar-05 Apr-05 May-05 Jun-05

9 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 Sampling Date Dec-04 Mar-05 Apr-05 Jun-05 Acetone Benzene U Chlorobenzene ,3-DCB ,4-DCB ,2-DCA cis-1,2-dce 2,800 1, PCE U 2 U TCE Vinyl Chloride J Total VOCs % Reduction Total VOCs (ppb) Dec-04 Jan-05 Feb-05 Mar-05 Apr-05 May-05 Jun-05

10 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 Sampling Date Dec-04 Mar-05 Apr-05 Jun-05 Acetone 4 U 4 U U Benzene J Chlorobenzene 1, U 3 1,3-DCB 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 J PCE 2 U 2 U U TCE 1.18 J 1 2 U 2 U Vinyl Chloride U 2 U Total VOCs % Reduction Total VOCs (ppb) Dec-04 Jan-05 Feb-05 Mar-05 Apr-05 May-05 Jun-05

11 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 Sampling Date Dec-04 Mar-05 Apr-05 Jun-05 Acetone 4 U 40 U Benzene 3 20 U U Chlorobenzene ,3-DCB ,4-DCB ,2-DCA cis-1,2-dce 1, PCE 0.36 J 20 U 1 U 2 U TCE Vinyl Chloride Total VOCs % Reduction 2500 Total VOCs (ppb) Dec-04 Jan-05 Feb-05 Mar-05 Apr-05 May-05 Jun-05

12 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 (%) Mass Reduction (ug/l) Percent Reduction (%) May-03 Mar-05 Apr-05 Jun Mass Reduction (ug/l) Percent Reduction (%) Mass Reduction (ug/l)

13 Pilot Study Design Considerations Why ISOTEC? Chelated Iron Catalyst Low Concentration of Hydrogen Peroxide More Controlled Reaction

14 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)

15 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

16 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

17 Full Scale Remedial Design Injection Well Configuration

18 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 (%) Mass Reduction (ug/l) Percent Reduction (%) May-03 Mar-05 Apr-05 Jun-05 Oct-05 Jan Mass Reduction Percent Reduction (%) Mass Reduction (ug/l)

19 Site Plan

20 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

21 Questions & Answers