FINAL DESIGN DOCUMENTS: WATER TREATMENT SYSTEM, OPERABLE UNIT ONE DUBLIN TCE SITE BUCKS COUNTY, PENNSYLVANIA Work Assignment No. 90-47-3NS3 Contract No. 68-W8-0090 March 1995 Prepared for U.S. Environmental Protection Agency Region III 841 Chestnut Street Philadelphia, Pennsylvania 19107 Prepared by CH2M HILL Reston, Virginia WDCR846/024.WP5 ' n SRGGOQO Preface This report contains the following design documents: • Engineer's Report • Design Plans (bound under separate cover) • Design Specifications WDCR848/023.WP5 flftOOOOO:2 ;,g|ft^^: • • "•'>•',?':"-"'l. • ' ' " ENGINEER'S REPORT Final Water Treatment System Operable Unit One Dublin TCE Site Bucks County Pennsylvania Prepared for the U.S. Environmental Protection Agency Region HI ..V-, -, 841 Chestnut Street % - ; Philadelphia, Pennsylvania 19107 Prepared by OMH'ILL Reston, Virginia March 1995 WDCR846/025.WP5/1 AR000003 This design document has been prepared under the direction of a Registered Professional Engineer. WDCR846/025.WP5/2 1ROOOOOI* CONTENTS Section Page Acronyms and Abbreviations 1.0 Introduction .................................... 1-1 2.0 Site Background ................................. 2-1 3.0 Existing Municipal Water Supply System .................. 3-1 3.1 Overview .................................. 3-1 3.2 Water Supply Wells and Well Houses ................ 3-1 3.2.1 Well Pumps ......................... 3-1 3.2.2 Disinfection Facilities .................... 3-3 3.2.3 Well Houses ......................... 3-3 3.3 Distribution Network: Existing and Proposed ........... 3-3 3.4 Elevated Tank Reservoir ........................ 3-5 4.0 Design Criteria ................................... 4-1 4.1 Overview ................................. 4-1 4.2 Design Codes and Standards ...................... 4-1 4.2.1 Federal Codes ........................ 4-1 4.2.2 Pennsylvania and Bucks County Codes ......... 4-1 4.2.3 Dublin Borough Codes ................... 4-2 4.3 Design Water Demands ........................ 4-2 4.3.1 Supply Well and Treatment Facility Flow Demands .......................... 4-2 4.3.2 Distribution System Flow and Pressure Demands .......................... 4-7 4.3.3 Storage Demands ...................... 4-9 4.3.4 Sewerage Demands ..................... 4-9 4.3.5 Provisions for Future Water Demands .......... 4-9 4.4 Design Water Quality Criteria ................... 4-10 4.4.1 Summary of Water Quality Standards and Results .......................... 4-10 4.4.2 Volatile Organic Compounds ......:....... 4-10 4.4.3 Manganese .......................... 4-10 4.4.4 Other Water-Quality Parameters ............ 4-10 5.0 Proposed Facility Description ......................... 5-1 5.1 Process Overview ............................ 5-1 5.2 Supply Well ................................ 5-1 5.2.1 Site Selection ......................... 5-1 5.2.2 Source "Exploration ..................... 5-3 SR000005 CONTENTS (continued) Section Page 5.2.3 Sources of Contamination .................. 5-4 5.2.4 Well Retrofitting ...................... 5- 5.3 Piping and Appurtenances ....................... 5 5.4 Manganese Sequestering System ................... 5-< 5.5 Multi-Staged Diffused Air Stripper .................. 5-7 5.6 Off-Gas Treatment System ....................... 5-8 5.7 Effluent Tank and Booster Pump ................... 5-8 5.8 Chlorination System ........................... 5-9 5.9 Autodialer Alarm System ...................... 5-10 5.10 Building and Site Features ...................... 5-10 5.10.1 Building Layout ...................... 5-10 5.10.2 Heating and Ventilation ................. 5-1.0 5.10.3 Site Layout ......................... 5-11 5.10.4 Site Utilities ........................ 5-11 5.10.5 Noise Abatement ..................... 5-11 5.11 Operational Tie-in to the Borough's Existing System ...... 5-13 5.12 Emergency Provisions ........................ 5-13 5.13 Operation and Maintenance ..................... 5-14 5.14 Facility Startup ............................ 5-14 5.15 Operator Training ........................... 5-14 5.16 Treatment System Monitoring .................... 5-15 5.17 Drought Contingency Plan ...................... 5-15 5.18 Water Conservation Measures .................... 5-15 6.0 Proposed House Connections, Carbon Filter Removal, and Well Abandonment ............................ 6-1 6.1 Installation of House Connections ..............".... 6-1 6.2 Removal and Disposal of Carbon Filters .............. 6-3 6.3 Abandonment of Private Wells ................... 6-15 7.0 Construction Cost Estimate ........................... 7-1 8.0 Construction Schedule . ............................. 8-1 References Appendix A Laboratory Analytical Data, Water Quality Samples Appendix B Diffused Air Stripper References and Performance Data Appendix C Treatment System Monitoring Plan Appendix D Treatment System Quality Assurance Project Plan Appendix E Borough of Dublin Drought Emergency Plan Appendix F Borough of Dublin Water Use Regulations and Conservation Measures CONTENTS (continued) Figures Page 2-1 Site Location Map ................................ 2-2 2-2 Site Map ...................................... 2-3 3-1 Existing and Proposed Water Distribution System ............. 3-2 5-1 Process Flow Diagram ............................. 5-2 6-1 Affected and Potentially Affected Properties for OU-1 Remedial Action ............................. 6-2 8-1 Construction Schedule (EPA Region III and PaDER Waste Management Only) ................................ 8-2 Tables 3-1 Existing Water-Supply Wells, Pumps, and Disinfection Equipment .................................... 3-4 3-2 Existing Distribution-System Reservoir .................... 3-6 4-1 Affected or Potentially Affected Residences and Businesses .................:,................ ; 4-3 4-2 Summary of Design Water Demands .................... ; 4-7 4-3 Analysis of Distribution Network ....................... 4-8 4-4 PaDER New Source Sampling and Testing Requirements for Community Water Systems—Groundwater Sources ........ 4-11 4-5 Summary of Groundwater Sampling Results, Proposed Supply Well .................................. 4-15 5-1 Specifications for the Supply Well and Pump ................ 5-5 5-2 Electrical Requirements ............................ 5-12 6-1 Water Service Connection Data Summary .................. 6-4 6-2 Carbon Filter Data Summary ........................ 6-10 6-3 Residential Supply Well Abandonment Data Summary ......... 6-16 7-1 Construction Cost Estimate (EPA Region III and PaDER Waste Management Only) .......................... 7-2 WDCR846/012.WP5 flROOOOO? List of Acronyms and Abbreviations • ARAR applicable or relevant and appropriate requirements ARCS Alternative Remedial Contracting Strategy BCDH Bucks County Department of Health CERCLA Comprehensive Environmental Response, Compensation, and Liability Act DRBC Delaware River Basin Commission EPA United States Environmental Protection Agency FFS focused feasibility study MCL maximum contaminant level NPL National Priorities List PaDER Pennsylvania Department of Environmental Resources PCE tetrachloroethylene PRP potentially responsible party PVC polyvinyl chloride RI/FS remedial investigation and feasibility study ROD record of decision RPM remedial project manager SOW statement of work TCA 1,1,1 trichloroethane TCE • trichloroethylene USGS United States Geological Survey VOC volatile organic compound WDCR846/026.WP5 AROG.GGQ8 Section 1.0 Introduction This report presents the design for the public water-supply well and treatment system part of the selected remedy for Operable Unit 1 (OU-1) of the Dublin TCE Superfund Site (the Site) in Dublin, Pennsylvania. OU-1 is one of the two operable units at the site. The primary objective of OU-1 is to provide a permanent supply of clean drinking water for approximately 70 residential and commercial properties whose private wells are contaminated, or may become contaminated, by trichloroethylene (TCE) migrating from the Site. OU-2 is a potentially responsible-party (PRP)-led operable unit focusing on remediating groundwater, surface water, and soil at the Site. The major components of the selected remedy for OU-1, as outlined in the record of decision (ROD) prepared by the U.S. Environmental Protection Agency (EPA-) and dated December 30, 1991, are the following: 1. Extending Dublin Borough's public water system to connect the affected parties to the system. 2. Developing, constructing, and operating a new public water-supply well within the plume of TCE contamination or converting an existing well within the plume of contamination to a public water-supply well and incorporating the well into the existing Dublin Borough municipal water-supply system to supplement the Borough's existing capacity at a rate equal to the average demands of the affected residences and businesses. 3. Constructing and operating an air-stripping system for treating groundwater extracted from the proposed supply well and treating the vapor emissions using vapor-phase carbon or another feasible technology. 4. Hooking up each of the affected residences and businesses to the public water system. • 5. Removing existing carbon adsorption units or discontinuing bottled-water service to the affected residences and businesses and disposing of the carbon in accordance with federal and state regulations. 6. Abandoning the private wells of residences and businesses that are or will be within the plume of contamination or implementing institutional controls on the development and use of the wells. 7. Until a final groundwater