Office of Solid Waste and EPA-540-R-11-006 Emergency Response June 2011 (5102G) www.epa.gov/tio www.clu-in.org/optimization Remediation System Evaluation (RSE) Baytown Township Superfund Site Lake Elmo, Minnesota REMEDIATION SYSTEM EVALUATION BAYTOWN TOWNSHIP SUPERFUND SITE LAKE ELMO, MINNESOTA Report of the Remediation System Evaluation Final Report June 30, 2011 Prepared by US Army Corps of Engineers Environmental and Munitions Center of Expertise NOTICE Work described herein was performed by the US Army Corps of Engineers Environmental and Munitions Center of Expertise (USACE CX) in Omaha, Nebraska for the U.S. Environmental Protection Agency (USEPA). Work conducted by the USACE CX, including preparation of this report, was performed under Work Assignment #58 of EPA contract EP-W-07-078. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. i PREFACE This report was prepared as part of a project conducted by the USEPA Office of Superfund Remediation and Technology Innovation (OSRTI) in support of the "Action Plan for Ground Water Remedy Optimization" (OSWER 9283.1-25, August 25, 2004). The objective of this project is to conduct Remediation System Evaluations (RSEs) at selected pump and treat (P&T) systems that are jointly funded by USEPA and the associated State agency. The project contacts are as follows: Organization Key Contact Contact Information USEPA Office of Superfund Jennifer Hovis USEPA Headquarters – Potomac Yard Remediation and Technology Construction and 2777 Crystal Drive Innovation Post-Construction Arlington, VA 22202 (OSRTI) Branch [email protected] Phone: 703/603-8888 USEPA Region V Leah Evison USEPA Region 5 Remedial Project 77 West Jackson Boulevard Manager Chicago, Illinois 60604 [email protected] Phone: 800/621-8431 Minnesota Pollution Control Kurt Schroeder Minnesota Pollution Control Agency Agency (MPCA) State Lead 520 Lafayette Road North Hydrogeologist St. Paul, Minnesota 56155-4191 [email protected] Phone: 651/757-2703 Terracon Brett Staeden Terracon Project Engineer 3535 Hoffman Road East White Bear Lake, Minnesota 55110-5376 [email protected] Phone: 651/770-1500 US Army Corps of Engineers Dave Becker US Army Corps of Engineers RSE Liason Environmental and Munitions Center of Expertise Omaha, Nebraska [email protected] Phone: 402-697-2655 ii TABLE OF CONTENTS NOTICE ......................................................................................................................................................... i PREFACE ..................................................................................................................................................... ii TABLE OF CONTENTS ............................................................................................................................. iii ACRONYM LIST ......................................................................................................................................... v 1.0 INTRODUCTION............................................................................................................................... 1 1.1 PURPOSE ........................................................................................................................................ 1 1.2 TEAM COMPOSITION...................................................................................................................... 2 1.3 DOCUMENTS REVIEWED ................................................................................................................ 2 1.4 BASIC SITE INFORMATION AND SCOPE OF REVIEW....................................................................... 3 1.4.1 LOCATION ...................................................................................................................... 3 1.4.2 SITE HISTORY, POTENTIAL SOURCES, AND RSE SCOPE ................................................ 3 1.4.3 HYDROGEOLOGIC SETTING/SITE CONCEPTUAL MODEL ................................................ 4 1.4.4 POTENTIAL RECEPTORS ................................................................................................. 6 1.4.5 DESCRIPTION OF GROUND WATER PLUME .................................................................... 6 2.0 SYSTEM DESCRIPTION .................................................................................................................. 8 2.1 EXTRACTION SYSTEM ................................................................................................................... 8 2.2 TREATMENT SYSTEM..................................................................................................................... 8 2.3 MONITORING PROGRAM ................................................................................................................ 9 3.0 SYSTEM OBJECTIVES, PERFORMANCE, AND CLOSURE CRITERIA ................................. 11 3.1 CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA .......................................................... 11 3.2 TREATMENT PLANT OPERATION STANDARDS ............................................................................ 12 4.0 FINDINGS ........................................................................................................................................ 13 4.1 GENERAL FINDINGS ..................................................................................................................... 13 4.2 SUBSURFACE PERFORMANCE AND RESPONSE ............................................................................ 13 4.2.1 PLUME CAPTURE.......................................................................................................... 13 4.2.2 GROUND WATER CONTAMINANT CONCENTRATION TRENDS ..................................... 15 4.2.3 DATA GAPS .................................................................................................................. 17 4.3 COMPONENT PERFORMANCE ....................................................................................................... 17 4.3.1 EXTRACTION SYSTEM .................................................................................................. 17 4.3.2 AIR STRIPPER ................................................................................................................ 18 4.3.3 SOLIDS FILTRATION SYSTEM ........................................................................................ 19 4.3.4 GROUNDWATER INFILTRATION SYSTEM ...................................................................... 20 4.3.5 SYSTEM CONTROLS ..................................................................................................... 20 4.3.6 ISCO PILOT STUDY ........................................................................................................ 21 4.3.7 PRIVATE WELL SAMPLING AND GAC MANAGEMENT PROGRAMS ................................. 22 4.4 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF ANNUAL COSTS ................. 22 5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN HEALTH AND THE ENVIRONMENT ............................................................................................................................. 24 5.1 GROUNDWATER ........................................................................................................................... 24 iii 5.2 SURFACE WATER ......................................................................................................................... 24 5.3 AIR ............................................................................................................................................ 25 5.4 SOIL ............................................................................................................................................ 25 5.5 WETLANDS AND SEDIMENTS ....................................................................................................... 25 6.0 RECOMMENDATIONS .................................................................................................................. 26 6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS .................................................................... 26 6.1.1 IMPLEMENT ISCO WITHIN SOURCE AREA ...................................................................... 26 6.1.2 PHASED IMPLEMENTATION OF ISCO SOURCE AREA TREATMENT ................................. 29 6.1.3 CONSIDERATION OF IN-SITU BIOLOGICAL TREATMENT ................................................ 32 6.1.4 POTENTIAL LIFE CYCLE COST SAVINGS OFFERED BY SOURCE AREA TREATMENT ....... 34 6.1.5 RECOMMENDATIONS FOR ADDITIONAL SOURCE AREA ASSESSMENT ........................... 36 6.1.6 PERFORMANCE-BASED CONTRACTING FOR SOURCE AREA TREATMENT ...................... 37 6.1.7 MORE RIGOROUS EVALUATION OF HYDRAULIC BARRIER CAPTURE INFLUENCE .......... 38 6.1.8 IMPROVEMENTS TO THE MONITORING PROGRAM ....................................................... 39 6.2 RECOMMENDATIONS TO REDUCE COSTS .................................................................................... 40 6.2.1 REDUCE BLOWER AIRFLOW RATE ................................................................................ 40 6.2.2 ADJUSTMENTS TO GAC MANAGEMENT PROGRAM ....................................................... 41 6.2.3 NO NEED FOR CLASS I, DIVISION I MOTORS .................................................................. 42 6.2.4 OPTIMIZATION OF GROUNDWATER MONITORING PROGRAM...................................... 42 6.3 RECOMMENDATIONS FOR TECHNICAL IMPROVEMENT ..............................................................