Managing a MGP Site Containing 121,000 Tons of Soils Containing Highly Impacted and Multiple Contaminates Of Concern (COC) Clinton, Iowa

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1 Managing a MGP Site Containing 121,000 Tons of Soils Containing Highly Impacted and Multiple Contaminates Of Concern (COC) Clinton, Iowa Dean Hargens, Alliant Energy Frank Kellogg, DCI Environmental. Inc. Kevin Larson, USEPA Region 7, OSC 1

2 Clinton MGP Site 1930 s Clinton MGP Site 1960 s 2

3 History of Site Interstate Power & Light Co. (IPL) Service Center Former Allied Steel Property (FAS) Separated by Railroad Years of Operation 1869 to 1954 Land Use IPL manufactured gas, electric generation, operating/service center FAS river back water, sluice pond, ASTs, city incinerator, fill area, steel manufacturing, vacant Regulatory History Iowa Department of Natural Resources (IDNR) 1989 USEPA Region IPL Administrative Order of Consent for investigation of MGP site 1997 Engineering evaluation/cost analysis (EE/CA) 2003 Consent Order 2004 Public Involvement City/CAG/Activist 3

4 USEPA Investigation Remedial Investigation Identified COCs EE/CA source removal (non time critical removal action) FAS lead contamination Phase 1 (455 CY), July 1997 FAS lead contamination Phase 2, (7,151 tons) December 2004 PCBs Phase 1 Impacted Soil Remediation Technologies Evaluated In-Situ Ex-Situ Biological Physical Fixation Soil vapor extraction Chemical Fixation Thermal Conductive Heating Asphalt Incorporation Steam Stripping Biological Land farming Vitrification Co-Burning at Generation Facility Solvent Extraction Material Substitute at Cement Kiln Chemical Oxidation Fixed Base Thermal Desorption (selected) Mobile Thermal Desorption (selected) 4

5 Impacted Soil Remediation EE/CA Removal Estimate 10,000 tons Negotiated Cleanup Levels All visible contamination IDNR Standards 100 mg/kg PAHc/ 500 mg/kg PAHt Compound Specific Risk based Soil Action Levels Compound 0 to 2 ft Below 2 ft Benzo(a)anthracene 28 mg/kg 310 mg/kg Benzo(a)pyrene 2.8 mg/kg 31 mk/kg Benzo(b)fluoranthene 28 mg/kg 310 mg/kg Benzo(k)fluoranthene 280 mg/kg 3,100 mg/kg Chrysene 2,800 mg/kg 31,000 mg/kg Dibenz(ah)anthracene 2.8 mg/kg 31 mg/kg Indeno(1,2,3-cd)pyrene 28 mg/kg 310 mg/kg PCBs (total) 25 mg/kg 25 mg/kg Lead 800 mg/kg 1,200 mg/kg 5

6 Air Monitoring Perimeter 5 real time fixed based stations Exclusion Zone Direct read instruments Total suspended particulates Hydrogen cyanide (HCN) Total VOCs Integrated Passive samplers for PAHs, lead, HCN & BTEX Laboratory Primary On-Site Laboratory Environmental Chemistry Consulting Services, Inc. (Madison, WI) Control Laboratories Keystone Laboratories, Inc. (Newton, IA) TestAmerica (Cedar Falls, IA) 6

7 Estimated Excavation Areas from EE/CA Clinton MGP Site IPL prior to excavation 7

8 Clinton MGP Site FAS prior to excavation Phase 1 - Years 2004/2005 MGP Impacted material transported to MTTD facility located in Cedar Rapids, Iowa 34,081 tons treated and used as landfill daily cover 1.2 tons of PCB contaminated material transported to Beatty, Nevada 8

9 DCIs Soil Management Facility Phase MTTD was relocated to Clinton site Testing for lead impacted soil 7,151 tons of lead impacted soil stabilized and stockpiled onsite Additional PCB testing non detected 48,405 tons of MGP impacted soil treated by the MTTD unit and used a site backfill Additional soil testing required upon finding a significant COC tar seam 9

10 IPL MTTD Unit at MGP Site Additional Soil Testing Detected high levels of COC s TPH equated to 51% Coal tar seam 200 x 250 x 4 average depth Approximately 12,000 tons of highly impact COC tar media Multiple COC level soil piles tested by an on-site lab to manage COC loading within the MTTD unit to comply with IDNR Air Quality and health and safety requirements 10

11 IPL MGP Source Tar Seam Phase Time critical material management based upon significant COC tar seam treatment impact Multiple COC level soil piles tested by an on-site lab to manage COC loading within the MTTD unit to comply with IDNR Air Quality and health and safety requirements 36,679 tons of MGP impacted soil treated by MTTD unit and used at site backfill Site grading, backfilling, placement of perimeter fencing and final backfill 11

12 2008 6,051 tons of stockpiled stabilized lead impacted soil transported offsite for disposal Installation of Eco-Prairie Restoration on FAS Installation of concrete parking on IPL Final Excavation Areas 12

13 Summary Administrative actions USEPA and IDNR Public Relations USEPA s decision expediency Lead impacted soil stabilization of 7,151 tons and shipped to SAL Excavation, soils management of 51% COC soils, treatment, testing, and backfill and compaction of 119,165 tons of MGP impacted media Summary (continued) 51% COC - accelerated reevaluation of treatment options 51% COC - required other soil management details Cost saving $4.0 M - Transportation $5.5 M - COC Management on-site $9.5 M - TOTAL 13

14 Yet to be completed Establishment of Eco-Prairie Vapor intrusion investigation Indoor air samples from 4-5 structures Determination of the nature and extent of the groundwater impacts from the site Groundwater risk evaluation Evaluation of potential groundwater remedial technologies Complete ground water treatability & feasibility studies Yet to be completed (continued) Long term quarterly ground water monitoring Implementation of institutional controls Implementation of Groundwater Remedy USEPA 5-year reviews (2017 & 2022) Site closure (2027) 14

15 Concrete Parking and Building Expansion IPL Eco-Prairie Restoration FAS 15