SPD and Power Plant Area SPD and Power
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SPD and Power Plant Area Groundwater Remediation Former State Hospital In Massachusetts March 4, 2014 Frank Ricciardi, PE, LSP – Weston & Sampson Medfield State Hospital 1 Agenda • Background • Bench Scale • Pilot Test Proposed Full Scale Approach • Schedule Treatment Area Medfield State Hospital 2 Medfield State Hospital 3 Property Overview • Primarily a residential facility for ~100 years • 440 acres ± historically – 225 acres ± today – Sledding Hill to be conveyed to Town – 80 acres ± for residential redevelopment – Open space around redevelopment and parcel along North Meadows Road conveyed to State Medfield State Hospital 4 Public Involvement Plan Site • Designated PIP Site • Extremely Active Public Participation • Permanganate P t ruled l d outt – Purple P l daylighting • Fox hunt, horses, and dog walkers galore • SHERC committee formed Medfield State Hospital 5 Special Project Designation • Special Project Designation submittal to Department of Environmental Protection (DEP) to address three MCP Areas • S Submittal b itt l simplifies i lifi regulatory l t and d public bli input process – One comprehensive program – Consolidates PIP groups under one program Medfield State Hospital 6 Background • Two Potential Source Areas – Degreasing using solvents (PCE) o SPD Area by Former Laundry Building o Power Plant Area • Non-Detect N D t t PCE in i S Soilil (<0 (<0.002 002 mg/kg) /k ) • PCE in Groundwater > Cleanup Standard (5 µg/L), up to 400 ppb • Seasonal Groundwater Sampling November 2009 - August 2013 Medfield State Hospital 7 SPD & PP Areas – PCE Extent A August t 2013 PP Area SPD Area I2 I1 Medfield State Hospital 8 Bench Scale Study Tested Oxidants Soil Samples SPD-TP-103 PP TP 10 PP-TP-105 Groundwater Samples SPD-MW-507 PP-MW-203 • Hydrogen y g Peroxide o Unstable o Short Half Life 1-9 hours in PP Area 4-19 hours in SPD Area • Sodium Persulfate (chosen) • Stable • Half life of approximately 18 days • Effective with Site soil and groundwater • Total Oxidant Demand, Soil Oxidant Demand and buffering capacity it off soils il ttested t d Medfield State Hospital 9 Pilot Test Oxidant Injection in SPD & PP Areas • 55 gallons at 50% Solution - Sodium Hydroxide (catalyst) • 1,250 gallons at 10% Solution – Sodium Persulfate Average Depth to Water • SPD Area: 13 ft bgs • PP Area; 15 ft bgs Injection & Monitoring Well Configuration M1 5 ft IW Existing Well M2 10 ft 15 ft 15 ft M3 Medfield State Hospital 10 Pilot Test – SPD Area • PCE Reduction Rate: 13 13.1 1 – 87.1% 87 1% • pH and ORP effects in all monitoring p points • Zone of Influence - 15 feet (Radius from injection point) • Results show Full-Scale application feasible Medfield State Hospital 11 Pilot Test – PP Area • PCE Reduction Rate: 19.6 – 43.4% • pH and ORP effects observed but nonnon radial • Zone of Influence is elliptical • Full Scale application is feasible with modifications • Pre-mix P i catalyst l and d oxidant id • Install injection wells in elliptical pattern Medfield State Hospital 12 Proposed Full Scale Injection Locations SPD Area ZOI: 15 ft radius 38 Injection Wells Power Plant Area ZOI: 30 x 15 ft 23 Injection Wells Medfield State Hospital 13 Planned Groundwater Monitoring • Before – Baseline • During – To ensure oxidant distribution • Post – To monitor contaminant destruction • Real Time Water Quality measurements throughout program – pH, ORP, DO, Cond • Monitor contaminants of concern; sodium and sulfates (ISCO components) Medfield State Hospital 14 Monitoring Network Medfield State Hospital 15 SPD Area Injections • High till surface – Drumlin • PCE believed to be present at overburden/till interface • Installed injection wells straddling interface • Irregular till surface • Injected j double volume around till elevation high point Medfield State Hospital 16 SPD Area Till Contours Medfield State Hospital 17 SPD Area Injections j Medfield State Hospital 18 SPD Area Injections Medfield State Hospital 19 Power Plant Concrete Medfield State Hospital 20 Power Plant Area Post Concrete Removal Medfield State Hospital 21 Power Plant Area Direct Application Medfield State Hospital 22 Post Direct Application Medfield State Hospital 23 Next Steps • • • • • Post Injection monitoring – April 2014 Data Evaluation S Second d iinjection j ti round dM May 2014 Third injection round (if needed) – July 2014 Post-remediation monitoring Medfield State Hospital 24 Project Team • Weston & Sampson – Lead Consultant • Redox Tech – Lead Remediation Contractor • JM Environmental – Earthwork/Environmental Contractor • ConTest Analytical – y Lab Lead Analytical Medfield State Hospital 25 Questions and Answers ? Medfield State Hospital 26
