SOIL REMEDIAL ACTION PLAN VILLAGE LAUNDRY DSCA SITE ID # DC410034 707 COLLEGE ROAD GREENSBORO, GUILFORD COUNTY, NC STATE CONTRACT NO.: N12001S AUTHORIZATION 021 AUGUST 21, 2017 Prepared for: North Carolina Department of Environmental Quality Division of Waste Management, Superfund Section 1646 Mail Service Center Raleigh, NC 27699 Prepared by: AECOM Technical Services of North Carolina, Inc. 5925 Carnegie Boulevard, Suite 370 Charlotte, NC 28209 Tel. (704) 553-6150 Certification I certify that, to the best of my knowledge, after thorough investigation, the information contained in or accompanied this certification is true, accurate, and complete. Kevin Arnold, PG, CHMM Project Manager Robert MacWilliams, PG Program Manager, Principal
Transcript
SOIL REMEDIAL ACTION PLAN VILLAGE LAUNDRY DSCA SITE ID # DC410034 707 COLLEGE ROAD GREENSBORO, GUILFORD COUNTY, NC STATE CONTRACT NO.: N12001S AUTHORIZATION 021 AUGUST 21, 2017
Prepared for:
North Carolina Department of Environmental Quality Division of Waste Management, Superfund Section 1646 Mail Service Center Raleigh, NC 27699 Prepared by: AECOM Technical Services of North Carolina, Inc. 5925 Carnegie Boulevard, Suite 370 Charlotte, NC 28209 Tel. (704) 553-6150 Certification I certify that, to the best of my knowledge, after thorough investigation, the information contained in or accompanied this certification is true, accurate, and complete.
Kevin Arnold, PG, CHMM Project Manager
Robert MacWilliams, PG Program Manager, Principal
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1.1 Current DSCA Petitioner .........................................................................................4 1.2 Current Property Owners .........................................................................................5 1.3 Objectives of the SRAP ...........................................................................................5
2.0 SUMMARY OF SITE ASSESSMENT DATA ...................................................................6
5.0 LAND USE RESTRICTIONS ...........................................................................................13
5.1 Notice of Dry-Cleaning Solvent Remediation .......................................................13 5.2 Annual DSCA Land-use Restrictions Certification ...............................................13 5.3 Analyses of Long Term Reliability & Feasibility of Engineering & Institutional
Controls ..................................................................................................................13 5.4 Criteria For Demonstration of Success ..................................................................14
6.1 Site Preparation ......................................................................................................15 6.2 Signage/Fencing .....................................................................................................15 6.3 Demolition of Red Brick building .........................................................................15 6.4 Utilities ...................................................................................................................15 6.5 Well Abandonment ................................................................................................16 6.6 Blending of COC-Impacted Soil ............................................................................16
6.6.1 Depth and Volume .....................................................................................16 6.6.2 Confirmatory Soil Sampling ......................................................................16
7.0 PROTECTION OF HEALTH & SAFETY OF ADJACENT RESIDENTIAL AND BUSINESS COMMUNITIES .......................................................................................................17
7.1 Limitation of Pedestrian Access to Property .........................................................17 7.2 Public Notification .................................................................................................17 7.3 Ambient Air Monitoring Plan ................................................................................17 7.4 Noise Control .........................................................................................................18
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Figure 1 Site Location Map Figure 2 Property Location Map Figure 3 Soil Analytical within Proposed Blending Area Figure 4 Most Recent Groundwater Analytical Results Figure 5 Comprehensive Soil Gas Map Figure 6 Comprehensive Indoor Air Map
APPENDICES
APPENDIX A – Evaluation of Remedial Measures APPENDIX B – Notice of Dry Cleaning Solvent Remediation APPENDIX C – Survey Plat showing locations of Land Use Restrictions APPENDIX D – “Annual DSCA Land-use Restrictions Certification” form APPENDIX E – Ambient Air Monitoring Plan
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1.0 INTRODUCTION
AECOM Technical Services of North Carolina Inc. (includes legacy URS and herein referred to as AECOM) has prepared a Soil Remedial Action Plan (SRAP) on behalf of the North Carolina Dry-Cleaning Solvent Cleanup Act (DSCA) Program to document proposed soil remediation activities associated with the former Village Laundry located at 707 College Road, Greensboro, Guilford County, North Carolina, as indicated on Figure 1 and 2. This SRAP has been prepared in accordance with the applicable requirements of 15A NCAC 02S .0507.
Dry-cleaning operations occurred at the former Village Laundry property from 1969 to 2004. During that time, companies which have operated at the facility are ACW Management and Master Kleen (Hangers of the Triad, B and C Management, C and K Investments and CMH LLC all operated under the name Master Kleen). The Master Kleen company has since been dissolved and no longer exists. As of 2004, the former dry-cleaner property has been occupied by a restaurant called One Wok and Grill.
Soil contamination associated with the former Village Laundry property extends onto an adjacent property (5804 Hunt Club Road) owned by Mr. William Sherrill. A property location map is included as Figure 2. This SRAP documents the proposed remediation of impacted soils on the Village Laundry and Sherrill properties.
For clarification purposes the former Village Laundry property will be referred to as such, or as the “source property”. The off-site property owned by Mr. Sherrill will be referred to as such, or as the “Sherrill Property”. Soils targeted for remediation located on both the source and off-site properties will be referred to herein as “source area soils”.
The SRAP does not directly address groundwater contamination identified beneath the source property or the Sherrill property, as well as other off-site properties within the contiguous area of groundwater impacts (which includes: 701 College Road/Hardee’s Restaurant, 609 College Road/CVS and Shops and 5939 Friendly Avenue/Westborough Apartment Complex). However, remediation of the source area soils will improve groundwater quality as leaching of contaminants from source area soils into groundwater will be greatly reduced resulting in a continual reduction in dissolved phase contaminant mass.
1.1 Current DSCA Petitioner
The DSCA site petitioner is the current owner of the 707 College Road property, G Partnership, LLC. G Partnership, LLC petitioned into the DSCA Program on April 15, 2009. Two building structures are located on the 707 College Road property. The One Wok and Grill restaurant (707A College Road) is located in the building and tenant space formerly occupied by the Master Kleen dry
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cleaners and the other building is occupied by the Village Laundromat (707 College Road) which solely functions as a coin operated laundromat.
1.2 Current Property Owners
The current owner of the 707 College Road property is G Partnership, LLC. A deed is on file for this property at the Guilford County Register of Deeds (Book # 005493, Page # 00115).
The current owner of the property adjacent to, and immediately west of the former Village Laundry, is Mr. William Sherrill. A deed is on file for this property at the Guilford County Register of Deeds (Book # 3425, Page # 725 & Book # 5493, Page # 113).
1.3 Objectives of the SRAP
AECOM has completed the SRAP to outline the proposed activities for remediation of the source area soil contamination resulting from former dry cleaning activities (source area soils are shown in Figure 3). Source area soil contamination is considered to be soils exhibiting contaminant concentrations above calculated Site Specific Target Levels (SSTLs) protective of residential groundwater Vapor Intrusion Screening Levels (VISLs) as discussed within Section 3.0.
Specifically, source area soils can leach/partition contaminants to the groundwater resulting in groundwater contamination which will migrate with groundwater flow away from the soil source. Contaminants in turn can volatilize from the impacted groundwater creating a potential vapor intrusion risk to overlying structures. The SRAP will demonstrate that soil blending using In-Situ Chemical Oxidation (Potassium Permanganate) is the most appropriate remedial option to address soils on the property and reduce soil contaminant concentrations to the SSTLs calculated to be protective of residential groundwater VISLs as discussed within Section 3.0.
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2.0 SUMMARY OF SITE ASSESSMENT DATA
Environmental assessment activities have been completed for the former Village Laundry site by AECOM on behalf of the DSCA Program.
2.1 Background
The release of chlorinated solvents, primarily tetrachloroethylene (PCE), from the former Village Laundry property was first discovered as part of groundwater sampling conducted during a Phase II Environmental Site Assessment performed at the Friendly Hills Apartments (currently Westborough Apartments) by ECS of Greensboro, NC in November 2006. The Westborough Apartments property is located 375 feet southwest and downgradient of the source property. A property location map is included as Figure 2. The Westborough Apartment Complex is now owned by Friendly Hills Apts., LLC.
On April 15, 2009, the source property was voluntarily petitioned into the DSCA Program by the property owner. The DSCA Program has completed several phases of investigation to evaluate the extent of soil, groundwater and soil vapor impacts likely attributable to the former dry-cleaning operations. The findings of these assessment activities have been documented in the reports below, which are available online at http://edocs.deq.nc.gov/WasteManagement/Search.aspx?cr=1 by entering DC410034 in the ID field or in the search bar at the top of the page.
• Assessment Report dated January 6, 2009; • Indoor Air Quality Evaluation Results dated January 27, 2010; • Prioritization Assessment Report dated March 18, 2011; • Indoor Air Vapor Quality Evaluation Results Report dated May 19, 2011; • Residential Indoor Air Vapor Quality Evaluation Results Report dated August 23, 2011; • Sub-slab Depressurization System Installation Report dated July 20, 2012; • Comprehensive Soil Gas Report dated August 23, 2012; • Indoor Air Quality Evaluation Results dated January 14, 2013; • Updated Soil Data Report for soil samples collected in February/August 2011 and July
2012 dated March 13, 2013; • Groundwater Analytical Report for February 2011, July 2012 and February 2013
sampling events dated March 25, 2013; • Indoor Air Vapor Quality Evaluation Results dated March 25, 2013; • Updated Soil Data Report dated March 13, 2013; • Remedial Options Evaluation dated April 18, 2013; • Updated Assessment Report dated September 27, 2013; • Residential Indoor Air Quality Evaluation Results Addendum – Building 32 Apartment C
dated November 7, 2013; • Sherrill Property Precursory Risk Assessment dated November 15, 2013; • Subslab Depressurization System Operations and Maintenance Manual dated December
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• Residential Indoor Air Quality Evaluation Results Addendum – Building 32 Apartment C dated March 19, 2014;
• Soil Gas Report dated July 25, 2014; • Soil Assessment Report dated November 6, 2014; • Residential Indoor Air Quality Evaluation Results Addendum – Building 32 Apartment C
dated November 10, 2014; • Updated Subslab Depressurization System Operations and Maintenance Manual dated
November 2014; • Residential Indoor Air Quality Evaluation Results Addendum – Building 32 Apartment C
dated May 13, 2015; • Groundwater Analytical Report dated May 26, 2015; • Residential Indoor Air Quality and Soil Gas Evaluation Results Building 32 Apartment C
and Permanent Soil Gas Point SG-41 Report, dated April 4, 2016; and, • Groundwater Analytical Report dated June 15, 2017.
A summary of the assessment activities is provided in sections 2.1.1 through 2.1.3.
2.1.1 Soil Assessment Activities
Forty soil borings were advanced from December 2008 through August 2014 as part of assessment activities completed to delineate the extent of soil impacts. Based on the results of the soil assessment activities an area of significantly impacted soils was identified straddling the boundaries of the source property and the Sherrill property, likely in proximity to where the garbage dumpster was located during the operation of the former dry-cleaner. Figure 3 displays comprehensive soil data collected from soil borings advanced as part of the soil quality assessment activities. As indicated on Figure 3, the primary contaminants of concern (COCs) detected in soil and their respective highest detected contaminant concentration are listed below:
• PCE at a concentration of 3,800 milligrams/kilogram (mg/kg); • Trichloroethylene (TCE) at a concentration of 49.3 mg/kg; and, • Vinyl chloride (VC) at a concentration of 4.9 mg/kg.
All of the highest concentrations were detected within soil boring SB-9 collected from a depth of 4-5 feet below ground surface (bgs) near the current location of the garbage dumpster. Comprehensive soil analytical results are included in Table 1.
2.1.2 Groundwater Sampling Activities
Groundwater assessment and groundwater quality monitoring were conducted from December 2008 through April 2017. These assessment activities included the installation and sampling of 12 permanent monitoring wells and one temporary monitoring well. A figure depicting the most recently collected groundwater quality data from each well is included as Figure 4.
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As indicated on Figure 4, the primary COCs detected in groundwater and their respective highest detected contaminant concentration include:
• PCE at a concentration of 92.2 milligrams per liter (mg/L) in temporary monitoring well TMW-1;
• TCE at a concentration of 4.61 mg/L in temporary monitoring well TMW-1; and, • VC at a concentration of 3.1 mg/L in monitoring well MW-3.
Comprehensive groundwater analytical results are included in Table 2.
The petroleum constituents detected in groundwater samples collected from monitoring wells MW-2 and MW-4 are attributed to a petroleum release from two 8,000 gallon gasoline underground storage tanks formerly located along the east side of the former Village Laundry Property (location of tanks shown in Figure 2). The tanks were reportedly removed on January 3rd, 1990 and the incident (incident number 8711) was closed on August 22, 1991 by the State of North Carolina Department of Environment, Health, and Natural Resources – Winston-Salem Regional Office. Soil and groundwater petroleum contamination resulting from the petroleum release is not addressed by this SRAP.
2.1.3 Vapor Intrusion Assessment
A total of thirty soil gas sampling points have been advanced as part of vapor intrusion assessment activities completed between September 2010 and February 2016 within the contiguous area of groundwater impacts. Eight of the thirty soil gas sampling points were converted to permanent sampling points. Permanent soil gas sampling locations are located within the Westborough Apartment Complex.
A total of ten structures/building spaces have been sampled for indoor air quality as part of vapor intrusion assessment activities conducted from December 2009 to February 2016. Results from the collected soil gas and indoor air samples are shown on Figures 5 and 6, respectively. As indicated on Figure 5, the primary COCs detected in soil gas and their respective highest detected contaminant concentration include:
• PCE at a concentration of 1,590 milligrams per meter cubed (mg/m3); • TCE at a concentration of 74.8 mg/m3; and, • VC at a concentration of 325 mg/m3.
The highest soil gas concentrations were all detected within soil gas boring SG-1. Comprehensive soil gas and indoor air analytical results are included in Tables 3 and 4, respectively.
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3.0 REMEDIAL GOALS
Based on the current and anticipated future use of the Sherrill property, inhalation of indoor air contaminant vapors is the primary exposure pathway in respect to potential risks associated with soil and groundwater contamination. The origin of the contaminant vapors responsible for this pathway is attributable to the volatilization of contaminants from impacted soil and groundwater underlying the Sherrill property and source property. Groundwater contamination in this area is resultant of the partitioning of contaminants from affected soils identified during soil assessment activities completed between December 2008 and August 2014.
In February 2017, AECOM and the DSCA Program established SSTLs for contaminated soil using the DSCA Risk Based Corrective Action Toolkit (DSCA Toolkit) to be protective of the residential groundwater VISLs at a distance of 0-feet (directly beneath source area) for soil. The DSCA Toolkit is used by DSCA to characterize risk using a series of equations and methodologies consistent with the Environmental Protection Agency (EPA) risk assessment guidance, including EPA Risk Assessment Guidance for Superfund (EPA, 1991 and EPA, 2004), EPA Soil Screening Guidance (EPA, 1996 and EPA, 2002), EPA Region 4 Human Health Risk Assessment Supplemental Guidance (EPA, 2014a), and the EPA Regional Screening Levels (RSL) website.
Based on the findings of the February 2017 DSCA Toolkit calculations, the analytes and their respective SSTLs are as follows:
TABLE A
As concentrations of PCE, TCE and VC are present in soil on the source property and Sherrill property at levels above the calculated SSTLs, these constituents are considered to be the primary contaminants specific to the development of this SRAP. The SSTLs were compared against existing soil data to define an area where soil impacts exceed the SSTLs and remediation should be considered.
Based on a comparison of the calculated SSTLs and the existing soil quality data as depicted in Figure 3, approximately 1,750 cubic yards (2,300 tons) of impacted soil requires remediation to prevent the continued leaching of contaminants from soil to groundwater resulting in groundwater contaminant concentrations exceeding the residential groundwater VISLs. The volume (1,750 cubic yards or 2,300 tons) is based on an estimated area of 3,945 square feet, and an assumed depth
Analyte Soil Protective of Residential GW VISL @ 0 ft.
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(thickness) of 12 feet which is the anticipated depth of groundwater in this area. The extent of the soil treatment area is shown on Figure 3.
After a negotiation period from late 2014 until October 4, 2016, Mr. William Sherrill and the DSCA Program entered into a Settlement Agreement such that the DSCA Program and their subcontractor could have access for performing soil remedial work on the Sherrill property. As part of the Settlement Agreement, the DSCA Program (or their contractor on behalf of DSCA) will demolish an approximate 2,100 square foot red brick building located on the east side of the Sherrill property to facilitate access to the contaminated soils requiring remediation. Figure 2 shows the location of the red brick building located on the Sherrill property.
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4.0 RECOMMENDED REMEDIATION STRATEGY
Based on the evaluation of six different soil remediation strategies (evaluation of the six remedial options is located in Appendix A), in-situ soil blending was chosen for the remediation strategy. In-situ soil blending involves the use of a mixer to distribute chemical amendments throughout the soil. Blending would occur throughout the area of contaminated soils exceeding the SSTLs to a depth of 12 feet bgs (approximate groundwater elevation) which is consistent with the depth of affected unsaturated soils. By immediately targeting and remediating the known source of contamination to 12 ft bgs, future groundwater contamination will be reduced.
In-situ blending will allow for direct contact between the chemical amendments and impacted soil. Activated persulfate, Potassium Permanganate, ABC+ and Daramend were evaluated as soil blending options (chemical amendments). Potassium Permanganate is an oxidizer and has been determined to be the most appropriate selection for in-situ soil blending. Potassium Permanganate will oxidize PCE, TCE and VC into harmless compounds and when used at the recommended product application concentrations, is not harmful to human health or the environment.
After removing asphalt on the east side of the affected area, soil blending would allow contaminated soils within the source area shown in Figure 3 to be treated on site. Additional volume created due to the application of the amendment will be used to “fill in” the depression left following the demolition and removal of the approximately 2,100-square foot red brick building on the Sherrill property. It is anticipated that approximately 52,000 pounds of Potassium Permanganate at a dose of 10 grams per kilogram would be mixed with the contaminated soil. The actual Potassium Permanganate amount will be determined based on analysis of soil samples collected for total oxidant demand prior to performing the soil blending activities.
It is probable that blending will weaken the bearing capacity of soils during/after the treatment. Portland cement (3 weight percent or 78 tons) will be mixed with the treated soil to regain soil strength in the event future building might occur in the area where soil blending activities have occurred. Soil blending will be a one-time activity with no O&M requirements expected.
Confirmation soil samples will be necessary to demonstrate that SSTLs have been met throughout the treatment area following the soil blending activities. Post treatment confirmation soil samples will be collected in accordance with applicable confirmatory sampling guidance specific to in-situ soil remedial actions to confirm blended soils are less than the SSTLs. Post treatment, boring locations and depths will be established within the source area for collecting soil samples. If soil samples contain concentrations greater than the SSTL, data will be averaged in accordance with an appropriate data averaging technique. An estimated 4 to 5 weeks will be required to complete the soil blending.
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Based on the remedial action chosen for achieving the contaminated soil SSTLs established in this SRAP, AECOM has recommended the following order of activities:
1) File and record a Notice of Dry Cleaning Solvent Remediation (NDCSR), with Land Use Restrictions pursuant to N.C. General Statute 143-215.104M with the Guilford County Register of Deeds office for the Sherrill property. Additional information concerning the NDCSR for the Sherrill property is provided in Section 5.
2) Obtain necessary permits from local and state entities prior to soil blending. For example, a pre-demolition permit will be obtained from City of Greensboro and the North Carolina Health Hazards Control Unit (HHCU) for the demolition of the approximate 2,100-square foot red brick building located on Mr. Sherrill’s property. The demolition and subsequent soil blending will not proceed until all necessary permits have been obtained.
3) Re-locate a utility pole currently located in the center of the “blending” area.
4) Demolish approximate 2,100-square foot red brick building on the Sherrill property. The aluminum coolers and concrete slab on which the aluminum coolers sit and the shop on the west side of the property will not be demolished. See Figure 2 for the locations of the 2,100-square foot red brick building and associated building structures.
5) Blend potassium permanganate with soil where soil contaminant concentrations exceed the SSTLs; anticipated to be approximately 3,945 square feet, or 1,750 cubic yards (2,300 tons) assuming a depth of 12 feet.
a. During the treatment process, additional volume of treated soils due to the extra volume created by the amendment would be directed into the depression formerly occupied by the 2,100-square foot red brick building on the Sherrill property.
6) Following the soil blending, Portland cement will be added to the treated soil to improve soil strength.
7) Collect confirmation soil samples from the treated soils within the treatment area to confirm soil contaminant concentrations are less than SSTLs.
8) Submit completion report to DSCA documenting soil blending and subsequent soil sampling activities.
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5.0 LAND USE RESTRICTIONS
Presented below is a summary of the restrictions which will be placed on the Sherrill property.
5.1 Notice of Dry-Cleaning Solvent Remediation
The risk assessment for the site was based on assumptions that usage of the site property will remain commercial and that groundwater will not be utilized on the property. Land-use restrictions will be implemented for the Sherrill property to ensure that land-use conditions are maintained and monitored until the land-use restrictions are no longer required for the site. A Notice of Dry-Cleaning Solvent Remediation was prepared for the site to comply with the land-use restriction requirement. The Notice of Dry-Cleaning Solvent Remediation, signed by Mr. William Sherrill on September 6, 2016, is included in Appendix B. A survey plat showing the locations and types of dry-cleaning solvent contamination on the property is included as Appendix C. The locations of dry-cleaning solvent contamination are where contaminants have been detected above unrestricted use standards. Soil quality data within the survey plat will be revised after the blending and confirmation soil sampling have been completed.
The Notice of Dry-Cleaning Solvent Remediation contains a clause which requires the owner of the site to submit a notarized “Annual DSCA Land-use Restrictions Certification” to the North Carolina Department of Environmental Quality (NCDEQ) on an annual basis certifying that the Notice of Dry-Cleaning Solvent Remediation remains recorded with the Register of Deeds and that land-use conditions have not changed. An example of such a notice is included in Appendix D. Documents relating to this site will be maintained by the NCDEQ.
5.3 Analyses of Long Term Reliability & Feasibility of Engineering & Institutional Controls
The land-use restrictions specified in the Notice of Dry-Cleaning Solvent Remediation prohibit site activities that could create unacceptable exposure to contaminated soil, groundwater, or vapor, and are intended to be temporary, but shall remain in force in perpetuity unless superseded or canceled by the Secretary of the NCDEQ. These restrictions include prohibiting the use of any surface or underground water at the site without the approval of the NCDEQ. Land-use restrictions are deemed to provide long term reliability as they are to be recorded in the Guilford County Register of Deeds and are to be observed by all owners of the property unless superseded or canceled by the Secretary of the NCDEQ.
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5.4 Criteria For Demonstration of Success
Demolition of the building will immediately eliminate the current indoor air exposure pathway for the property as no inhabitable structures other than the shop in the northwest corner will exist on the property. Compliance with item number 3 of the Land Use Restrictions within The Notice of Dry-Cleaning Solvent Remediation will prohibit future activities that cause or create a vapor intrusion risk. Compliance with the Notice of Dry-Cleaning Solvent Remediation will be the responsibility of the property owner.
At the request of the property owner, restrictions can be canceled by the NCDEQ after risk to public health and the environment associated with the dry-cleaning solvent contamination and any other contaminants included in the dry-cleaning solvent assessment and remediation agreement has been eliminated.
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6.0 ENGINEERING DESIGN
Presented below is a summary of the planned soil remediation activities.
6.1 Site Preparation
Site preparation activities include establishment of a visitor check-in area, decontamination area, and staging areas (predominantly Mr. Sherrill’s property). Equipment and supply storage areas will be established, as needed, adjacent to the appropriate work areas. Personnel and equipment decontamination areas will be constructed and identified in accordance with the site-specific Health and Safety Plan requirements.
Environmental protection controls will include potential air emissions from the blending process. These controls will be in place prior to initiating land disturbing activities. Best management practices will be implemented to control, minimize and/or prevent the release of impacted tailings entrained in storm water discharges. Dust control measures may be implemented in areas having the potential to produce dust, such as mixing areas.
6.2 Signage/Fencing
A temporary construction fence will be installed around the Sherrill property which will extend outside the perimeter of the blending area on the former Village Laundry property. The fence will remain in place until blending and confirmation soil sampling are complete. Warning signs will be placed on the fence along each boundary.
6.3 Demolition of Red Brick building
The red brick building on the Sherrill property will be demolished prior to beginning blending activities. Asbestos within the building will be removed prior to demolition in accordance with applicable HHCU regulations for asbestos abatement. A demolition permit will be submitted to the HHCU 10 days prior to beginning the demolition. Remnants of the building will be transported to the appropriate disposal facility.
6.4 Utilities
Prior to excavation activities, all subsurface utilities shall be located on the former Village Laundry and Sherrill properties by a utility locating contractor. The utility pole within the middle of the proposed blending activities will be relocated by Duke Energy prior to implementation of blending activities.
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6.5 Well Abandonment
Prior to blending activities, monitoring well MW-3, located within the vicinity of the work area, will be abandoned in accordance with North Carolina regulation 15A NCAC 2C 0.113 and .0214 by a North Carolina licensed drilling firm. Additional monitoring wells (MW-1 and MW-10) may need to be abandoned prior to blending.
6.6 Blending of COC-Impacted Soil
The estimated limits of the blending area are shown on Figure 3. Presented below is a summary of the planned blending activities.
6.6.1 Depth and Volume
The proposed blending excavation dimensions (subject to change based on unexpected utilities, etc.) are approximately 3,945 square feet, or 1,750 cubic yards (2,300 tons) assuming a thickness of 12 feet. Proposed costs (approximately $300,000) for the blending activities include a potassium permanganate dose of 10 grams per kilogram, which equates to 52,000 pounds of potassium permanganate. Prior to performing the blend, a soil sample(s) will be collected and analyzed for total oxidant demand to more accurately determine the proper dose for the site.
6.6.2 Confirmatory Soil Sampling
Post treatment confirmation soil samples will be collected in accordance with applicable confirmatory sampling guidance specific to in-situ soil remedial actions to confirm soils are less than the SSTLs. Locations of the soil samples and the depth at which they will be collected will be determined based on field conditions and applicable confirmatory sampling guidance for soil blending. Soil samples defining the extent of the blend area have already been collected.
6.7 Blending Portland Cement
Portland cement will be blended into the treatment area. A three weight % application rate of Portland cement will be used for the treatment area which includes the area which will be filled in following the demolition of the red brick building. 6.8 Demobilization
Upon completion of remedial activities, equipment will be decontaminated before being transported off site. All temporary facilities such as staging areas, work areas, temporary structures, stockpiles of excess materials, and other signs of construction activities will be removed. Personal protective equipment and other waste materials generated during remedial activities will be properly disposed of in accordance with local, state, and federal laws and regulations. Areas where remedial activities occurred will be left in a clean and stable condition prior to fully demobilizing from the property.
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7.0 PROTECTION OF HEALTH & SAFETY OF ADJACENT RESIDENTIAL AND BUSINESS COMMUNITIES
The blending process is expected to be completed within a four to five week period. DSCA will provide notification to the City of Greensboro and contiguous property owners of the scheduled start and end date of the blend. DSCA has required the development of the following work practices to ensure the protection of the health and safety of the surrounding community members during this work.
7.1 Limitation of Pedestrian Access to Property
A temporary six-foot chain link security fence with privacy screening will be erected along the perimeter of the treatment area and the Sherrill property boundary to restrict pedestrian and vehicular access during the blending activities. Sidewalks along the south side of Hunt Club Road and west side of Francis King Street will remain open. Proper signage warning against trespassing will be placed along each side of the temporary fence.
7.2 Public Notification
At least two weeks prior to the scheduled remedial activities, property owners within and contiguous to the contamination plume, and interested parties that have provided contact information, will be notified of the dates of the scheduled remedial activities, which will also be posted on the DSCA website (http://ncdenr.gov/web/wm/dsca/bbt_updates). In the case of properties with multiple residents, similar to the Westborough Apartment Complex, the property manager will be contacted and made aware of the remedial activities and pending implementation schedule. The property manager will communicate with any residents requesting information on the activities.
Prior to the remedial activities, questions regarding the SRAP can be directed to Michael Cunningham at 919-707-8361.
DSCA will post a schedule along with weekly updates on the status of the remediation on its website at www.ncdsca.org, and e-mail the update to interested parties that have provided contact information. The weekly status updates will include an updated schedule and descriptions of conditions encountered during the weekly reporting period. These updates will begin one week after blending activities commence at the subject property.
7.3 Ambient Air Monitoring Plan
An ambient air monitoring plan is provided within Appendix E.
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7.4 Noise Control
DSCA will require that the blending contractor perform work between the hours of 7 am and 6 pm. During those hours noise typical of blending equipment, asphalt saws, trackhoes, and dump trucks (including back up alarms) is to be expected.
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8.0 SCHEDULE
It is anticipated that the proposed soil blending will be completed in 4 to 5 weeks. Additional treatment may be required, pending confirmation soil sample data/soil data quality averaging if necessary. Soil sample results will be used exclusively to determine if additional treatment is necessary.
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9.0 BUDGET ESTIMATE
The proposed cost of the soil blending remedial action activities, based on projects of similar scope and other applicable environmental cost estimating tools, is estimated to be approximately $300,000. This cost does not include the following:
• Oversight, management and travel for AECOM personnel; • Relocating the utility pole; • Demolition of the red brick building on the Sherrill property; • Monitoring well abandonment prior to soil blending activities; • Field monitoring equipment; • Analytical costs for soil samples collected post soil blending activities; • Applying asphalt on the former Village Laundry property post soil blending activities; and, • Post soil blending reporting.
All results reported in mg/kg (milligrams per kilogram) on a dry-weight basisNC - Not calculatedJ - Estimate ValuePCE - TetrachloroetheneTCE - Trichloroethenecis-1,2-DCE - cis-1,2-Dichloroethenetrans-1,2-DCE - trans-1,2-DichloroetheneVC - Vinyl Chloride1,1-DCE - 1,1-Dichloroethene
Results bolded indicate exceedance of Inactive Hazardous Site Branch (IHSB) Residential Preliminary Soil Remediation Goal (PSRG) last updated October 2016.
Results shaded in blue indicate exceedance of Site Specific Target Levels (SSTLs).
Table 8: Analytical Data for GroundwaterDSCA ID No.: DC410034
Table 4: Analytical Data for Soil GasDSCA ID No.: DC410034
Ben
zene
cis-
1,2-
Dic
hlor
oeth
ylen
e
Ethy
lben
zene
Met
hyl t
ert-b
utyl
eth
er(M
TBE)
Nap
htha
lene
Tetra
chlo
roet
hyle
ne
Tolu
ene
trans
-1,2
-Dic
hlor
oeth
ylen
e
Tric
hlor
oeth
ylen
e
Vin
yl c
hlor
ide
Xyl
enes
(tot
al)
SG-1 6 0.5h 9/21/10 NA 278000 NA NA NA 2E+06 NA <28000 74800 325000 NA
SG-2 6 0.5h 9/21/10 NA 951 NA NA NA 132 NA 114 495 741 NASG-3 6 0.5h 9/21/10 NA 97100 NA NA NA <6300 NA <3700 <5000 84200 NA
SG-20 6 0.5h 2/22/11 NA <2.7 NA NA NA 4.69 NA <2.7 <3.7 <1.7 NASG-21 6 0.5h 2/22/11 NA <2.7 NA NA NA 1370 NA <2.7 56.8 <1.7 NASG-22 6 0.5h 2/22/11 NA <2.7 NA NA NA <4.6 NA <2.7 <3.7 <1.7 NASG-23 6 0.5h 2/22/11 NA <2.5 NA NA NA <4.3 NA <2.5 <3.4 <1.6 NASG-24 6 0.5h 2/22/11 NA 629 NA NA NA 13600 NA <240 1010 <150 NA
SG-31 6 0.5h 8/24/11 NA <60 NA NA NA 159 NA <60 <81 <38 NASG-32 6 0.5h 8/24/11 NA <3 NA NA NA <5.1 NA <3 7.65 <1.9 NASG-33 6 0.5h 8/24/11 NA <3.2 NA NA NA <5.5 NA <3.2 <4.4 <2.1 NASG-34 6 0.5h 8/24/11 NA 10.2 J NA NA NA 292 NA <67 <91 <43 NASG-35 6 0.5h 8/24/11 NA 6.45 NA NA NA 25.5 NA < 3.2 0.42 J 0.76 J NA
SG-4 6 0.5h 8/25/11 NA 131000 NA NA NA 54900 NA 2330 43900 <640 NASG-5 6 0.5h 8/25/11 NA 4.03 NA NA NA 405 NA < 3.5 18.6 <2.2 NA
SG-41 6 0.5h 10/18/11 NA <1.5 NA NA NA 22.9 NA <1.5 1.1 <0.47 NASG-42 6 0.5h 10/18/11 NA <1.5 NA NA NA <1.2 NA <1.5 <0.99 <0.47 NASG-43 6 0.5h 10/18/11 NA <1.8 NA NA NA 2.6 NA <1.8 <1.2 <0.56 NASG-44 6 0.5h 10/18/11 NA <1.5 NA NA NA 5.6 NA <1.5 <0.99 <0.47 NASG-45 6 0.5h 10/18/11 NA <1.4 NA NA NA <1.2 NA <1.4 <0.95 <0.45 NASG-46 6 0.5h 10/19/11 NA <1.5 NA NA NA <1.2 NA <1.5 <0.99 <0.47 NASG-47 6 0.5h 10/19/11 NA <1.5 NA NA NA <1.3 NA <1.5 <1 <0.49 NASG-48 6 0.5h 10/19/11 NA <1.6 NA NA NA <1.4 NA <1.6 <1.1 <0.51 NASG-49 6 0.5h 10/19/11 NA <1.4 NA NA NA <1.2 NA <1.4 <0.95 <0.45 NA
Sam
ple
ID
Sam
plin
g D
ate
(mm
/dd/
yy)
Dep
th[f
eet b
gs]
[µg/m3]Sam
ple
Dur
atio
n 1
ADT 4
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Table 3 - Comprehensive Soil Gas Results
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Table 4: Analytical Data for Soil GasDSCA ID No.: DC410034
Ben
zene
cis-
1,2-
Dic
hlor
oeth
ylen
e
Ethy
lben
zene
Met
hyl t
ert-b
utyl
eth
er(M
TBE)
Nap
htha
lene
Tetra
chlo
roet
hyle
ne
Tolu
ene
trans
-1,2
-Dic
hlor
oeth
ylen
e
Tric
hlor
oeth
ylen
e
Vin
yl c
hlor
ide
Xyl
enes
(tot
al)
Sam
ple
ID
Sam
plin
g D
ate
(mm
/dd/
yy)
Dep
th[f
eet b
gs]
[µg/m3]Sam
ple
Dur
atio
n 1
ADT 4
SG-50 6 0.5h 10/19/11 NA <1.4 NA NA NA <1.2 NA <1.4 <0.95 <0.47 NA
SG-41 6 0.5h 6/24/14 NA <1.8 NA NA NA 2.5 NA <1.8 <1.2 <0.58 NASG-42 6 0.5h 6/24/14 NA <1.5 NA NA NA <1.3 NA <1.5 <1.0 <0.48 NASG-47 6 0.5h 6/24/14 NA <1.5 NA NA NA <1.3 NA <1.5 <1.0 <0.48 NASG-80 6 0.5h 6/25/14 NA <1.5 NA NA NA 1.2 J NA <1.5 0.76 J <0.48 NASG-81 6 0.5h 6/25/14 NA <1.4 NA NA NA <1.2 NA <1.4 0.81 J <0.46 NASG-82 6 0.5h 6/25/14 NA <1.4 NA NA NA 4.9 NA <1.4 0.71 J <0.46 NASG-83 6 0.5h 6/25/14 NA 2.3 NA NA NA <1.6 NA <1.9 4.6 <0.62 NASG-84 6 0.5h 6/25/14 NA <5.5 NA NA NA <4.7 NA <5.5 <3.7 <1.8 NA
SG-41 6 0.5h 3/7/16 NA <0.40 NA NA NA 9.5 NA <0.40 <0.10 <0.10 NA
1 Indicate "G" for grab sample or for longer samples indicate the number of hours followed by "h".
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Table 3 - Comprehensive Soil Gas Results
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Table 5: Analytical Data for Indoor and Outdoor AirDSCA ID No.: DC410034
Ben
zene
cis-
1,2-
Dic
hlor
oeth
ylen
e
Ethy
lben
zene
Met
hyl t
ert-b
utyl
eth
er(M
TBE)
Nap
htha
lene
Tetra
chlo
roet
hyle
ne
Tolu
ene
trans
-1,2
-Dic
hlor
oeth
ylen
e
Tric
hlor
oeth
ylen
e
Vin
yl c
hlor
ide
Xyl
enes
(tot
al)
Indoor Air 12/14/09 F SU 8h NA 0.1 NA NA NA 6.6 NA0.0096
J 0.13 <0.013 NAOutdoor
Air 12/14/09 F SU 8h NA 0.032 J NA NA NA 0.23 NA0.0092
J 0.039 J <0.013 NA
Indoor Air 04/29/10 F O 14d NA <0.12 NA NA NA 26 NA <0.12 0.36 <0.19 NAOutdoor
Air 04/29/10 F O 14d NA <0.12 NA NA NA 0.64 NA <0.12 <0.072 <0.19 NA
Hardees-IA-1 02/22/11 C SU 8h NA 0.025 J NA NA NA 0.33 NA 0.019 J 0.056 0.024 NA
Building 32 APT C 06/02/11 R SU 24h NA 2.2 NA NA NA 41 NA 0.05 3 0.018 NA
Building 32-APT C- 07/22/11 R SU 24h NA 6.3 NA NA NA 90 NA 0.19 8.3 0.035 NA
18E-IAQ-1 11/15/11 R SU 24h NA0.0054
J NA NA NA <0.68 NA <0.04 0.019 J 0.007 J NA
28B-IAQ-2 11/15/11 R SU 24h NA <0.04 NA NA NA <0.68 NA <0.04 0.024 J0.0085
J NA
BLDG 32 APT C IA-
303/13/12 R SU 24h
NA 0.32 NA NA NA 9.8 NA 0.012 J 0.61 0.031 NAIA-
APT26C-1 03/13/12 R SU 24hNA 0.032 J NA NA NA 1.4 NA <0.04 0.047 J 0.029 NA
BLDG 32 APT C IA-
407/26/12 R SU 24h
NA 0.76 NA NA NA 10 NA 0.015 J 0.79 0.022 NA
IA-Sherrills-1 11/13/12 AD SU 8h NA <0.14 NA NA NA 0.61 NA <0.14 <0.19 <0.09 NA
Sam
ple
Loca
tion
1
Sam
plin
g D
urat
ion 3
Sam
plin
g M
etho
d 2
Sam
ple
ID
Sam
plin
g D
ate
(mm
/dd/
yy)
[µg/m3]
ADT 5
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Table 4 - Comprehensive Indoor Air Results
kevin.arnold
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kevin.arnold
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Table 5: Analytical Data for Indoor and Outdoor AirDSCA ID No.: DC410034
Ben
zene
cis-
1,2-
Dic
hlor
oeth
ylen
e
Ethy
lben
zene
Met
hyl t
ert-b
utyl
eth
er(M
TBE)
Nap
htha
lene
Tetra
chlo
roet
hyle
ne
Tolu
ene
trans
-1,2
-Dic
hlor
oeth
ylen
e
Tric
hlor
oeth
ylen
e
Vin
yl c
hlor
ide
Xyl
enes
(tot
al)
Sam
ple
Loca
tion
1
Sam
plin
g D
urat
ion 3
Sam
plin
g M
etho
d 2
Sam
ple
ID
Sam
plin
g D
ate
(mm
/dd/
yy)
[µg/m3]
ADT 5
IA-Apt. 32C 02/28/13 R SU 24h NA 0.092 NA NA NA 1.3 NA <0.14 0.18 <0.090 NA
BLDG 32 APT C IA-
609/11/13 R SU 24h NA 0.20 NA NA NA 8.3 NA <0.14 0.34 <0.090 NA
BLDG 32 APT C IA-
703/07/14 R SU 24h NA <0.14 NA NA NA 0.34 NA <0.14 <0.19 <0.09 NA
BLDG 32 APT C IA-
809/10/14 R SU 24h
NA 0.45 NA NA NA 11 NA <0.14 0.90 <0.090 NA
BLDG 32 APT C -A-
903/26/15 R SU 24h
NA <0.14 NA NA NA 0.83 NA <0.14 0.087 J <0.090 NA
BLDG 32 APT C -A-
1002/05/16 R SU 24h
NA <0.14 NA NA NA 0.22 J NA <0.14 <0.19 <0.090 NA
Notes:1 Indicate "F" for former or current dry-cleaning facility, "AD" for adjacent space, "R" for residence, "C" for commercial not adjacent space. If sample was taken outdoors, leave blank.2 Indicate "SU" for summa canister, "FC" for flux chambers, "T" for tedlar bags, "P" for passive samplers, "O" for other.3 Indicate "8h" for 8-hour, "24h" for 24-hour, "G" for grab sample, for other hours indicate the number of hours followed by "h" or "d" for days.
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Table 4 - Comprehensive Indoor Air Results
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800
850
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PRIC
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RD
LIPS
CO
MB
RD
S SW
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RD
NILE
PL
SATIN W
OO
D D
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KING GEO
RGE
DR
BALLINGER RD
FOX
CHAS
E RD
COLL
EGE
RD
FOXFIRE DR
MEADOW
OOD
ST
VILLAGE LN
DOLLEY
MADIS
ON RD
HOBBS RD
HORNADAY RD
OLLE
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AM
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AN
AV
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WESTWIND DR
OLD OAK RIDGE RD
BIG TREE WAY
GREEN MEADOW DR
COUNTR
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ARCADIA DR
BLEDSOE DR
GREENLEE RD
CO
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DO
DR
MA
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TTA
RD
CHIM
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ROCK
PL
STAG
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CH
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SPR
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TIM
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TOWER
RD
W FRIENDLY AVE
GARDEN
LAKE DR
BEC
KWIT
H D
R
LEAWO
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DR
NATHAN
HUNT
RD
AIN
SW
ORTH DR
NDLY RD
W FRIENDLY AVE
BUCKHORN RD
BUDDINGWOOD DR
OV
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ST
EDWAR
DIA
DR
TOMAHAWK DR
BURNT POPLAR RD
N C
HIM
NEY
RO
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STAG
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FUQUAY PL
GAR
DE
N VILLAGE WAY
SPAN
ISH OAK DR
QUAIL HOLLOW
RDN
EW G
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DEN
RD
GUIDA DR
DOBSON RD
COUNTRY LN
HIGH
WOO
DS BL
VD
CARLY'S W
AY
NC
REEK
RD
ALO
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D
FRIEN
DW
AY RD
LEA RAY DR
AUBURNDALE DR
KNIG
HTW
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D D
R
NORTHLAKE
DR
K
CH
IMN
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OC
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OLD
STAG
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OA
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TR
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N D
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HEN
LN
FLEMING TERRACE RD
RICHLAND ST
HUNT CLUB RD
JOSEPH M BRYAN BLVD
DOVER AVE
Horsepen Cr
S Buffalo
FriendlyLake
GuilfordColl
GuilfordCollege
Guilford
9
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9
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URS CORPORATION - NORTH CAROLINA5925 CARNEGIE BOULEVARD, SUITE 370
Building 32 Apt C IA-10 (2/5/16)PCE - 0.22 J ug/m3
TCE - <0.19 ug/m3
cis-1,2-DCE - <0.14 ug/m3
trans-1,2-DCE - <0.14 ug/m3
VC - <0.090 ug/m3
Building 28B-IAQ-2 (11/15/11)PCE - <0.68 ug/m3
TCE - 0.024 J ug/m3
cis-1,2-DCE - <0.04 ug/m3
trans-1,2-DCE - <0.04 ug/m3
VC - 0.0085 J ug/m3
Building 26C-IAQ-1 (3/13/12)PCE - 1.4 ug/m3
TCE - 0.047 J ug/m3
cis-1,2-DCE - 0.032 J ug/m3
trans-1,2-DCE - <0.04 ug/m3
VC - 0.029 ug/m3
Building 18E-IAQ-1 (11/15/11)PCE - <0.68 ug/m3
TCE - 0.019 J ug/m3
cis-1,2-DCE - 0.0054 J ug/m3
trans-1,2-DCE - <0.04 ug/m3
VC - 0.007 J ug/m3
Hardees-IA-1 (2/22/11)PCE - 0.33 ug/m3
TCE - 0.056 ug/m3
cis-1,2-DCE - 0.025 J ug/m3
trans-1,2-DCE - 0.019 J ug/m3
VC - 0.024 ug/m3
IA-Sherrills-1 (11/13/12)PCE - 0.61 ug/m3
TCE - <0.19 ug/m3
cis-1,2-DCE - <0.14 ug/m3
trans-1,2-DCE - <0.14 ug/m3
VC - <0.09 ug/m3
TG
ST
S KI
NG
ANC
ISFR
A
Indoor Air (12/14/09)PCE - 6.6 ug/m3
TCE - 0.13 ug/m3
cis-1,2-DCE - 0.1 ug/m3
trans-1,2-DCE - 0.0096 J ug/m3
VC - <0.013 ug/m3
Radiello Indoor (4/29/10)PCE - 26 ug/m3
TCE - 0.36 ug/m3
cis-1,2-DCE - <0.12 ug/m3
trans-1,2-DCE - <0.12 ug/m3
VC - <0.19 ug/m3
Radiello Outdoor (4/29/10)PCE - 0.64 ug/m3
TCE - <0.072 ug/m3
cis-1,2-DCE - <0.12 ug/m3
trans-1,2-DCE - <0.12 ug/m3
VC - <0.19 ug/m3
Outdoor Air (12/14/09)PCE - 0.23 ug/m3
TCE - 0.039 J ug/m3
cis-1,2-DCE - 0.032 J ug/m3
trans-1,2-DCE - 0.0092 J ug/m3
VC - <0.013 ug/m3
APPENDIX A
Village Laundry DC410034 Evaluation of Remedial Measures
1 | P a g e Evaluation of Remedial Measures
1.0 EVALUATION OF REMEDIAL MEASURES
AECOM and the DSCA Program evaluated several soil remedial technologies to achieve the desired SSTLs for the source and Sherrill properties. The evaluated area for each technology is depicted in Figure 3 of the Soil Remedial Action Plan and is estimated at approximately 3,945 square feet, or 1,750 cubic yards (2,300 tons) assuming a depth (thickness) of 12 feet. Depending on the type of remediation evaluated, costs are not included for the following:
• Relocating an active utility pole located within the area of soils targeted for remediation. • Demolition of the approximate 2,100 square foot red brick building on the Sherrill
property. • Management and oversight of the project by AECOM personnel. • Analytical costs for contained-in policy and confirmation soil sampling, where
applicable. • Re-asphalting the parking lot.
Pursuant to 15A NCAC 02S .0507 (b)(2), the following subsections discuss each of the evaluated remedial technologies based on the analysis of the following factors:
1) Practical Considerations for Implementing the Technology – Evaluates the requirements necessary to perform the remediation work including ease of construction, site accessibility and required permits.
2) Operation & Maintenance (O&M) Requirements – Evaluates the requirements needed for multiple return trips to the site to perform remediation system equipment maintenance.
3) Risks and Effectiveness of the Proposed Remediation – Evaluates the type, frequency, and duration of any post remediation activity that may be needed including, O&M, monitoring, inspections and other activities necessary to protect public health, safety and the environment.
4) Long Term Reliability and Feasibility of Engineering and Institutional Controls – Evaluates the future effectiveness of the remedial technology (e.g. will further work need to occur?) and the potential for return site visits and additional remediation of breakdown chemicals or by-products formed by natural processes.
5) Technical Feasibility of the Proposed Method – Evaluates the potential success of the remediation technology to reduce the concentrations of COCs at the site to below the targeted SSTLs.
Village Laundry DC410034 Evaluation of Remedial Measures
2 | P a g e Evaluation of Remedial Measures
6) Estimated Time Required to Achieve Established SSTLs – Evaluates the time needed to perform the remediation services to satisfy established contaminant reduction requirements.
7) Cost Effectiveness of Proposed Remediation When Compared to Other Remediation Alternatives – Compares the potential remediation costs with other remediation technologies considered to meet the SSTLs for this site. The preliminary costs included under each scenario do not include AECOM labor to manage project or analytical costs for contained-in soil sampling if applicable. Also, costs are not included for demolishing the red brick building located on the Sherrill property.
8) Community Acceptance – Evaluates the degree of public acceptance the remediation technology is likely to receive.
1.1 Excavation and Offsite Disposal
Excavation is the removal of contaminated material from a site using heavy construction equipment. Excavation is accomplished by digging up the contaminated soils that exceed SSTLs and loading them into containers for subsequent testing (to determine waste classification) and eventual transport from the property. The excavation will reach a maximum depth of 12 feet bgs which is the approximate depth to groundwater.
It has been determined that a portion of the soil contaminant concentrations within the source area are considered hazardous and will require disposal at a Subtitle C facility since they contain PCE above 14 mg/kg. The approximate area of PCE affected soils that exceed 14 mg/kg and will require disposal at a Subtitle C facility is approximately 270 cubic feet (approximately 540 tons) and is depicted in Figure 3 of the Soil Remedial Action Plan.
Excavated soils will be transported to a Subtitle D or Subtitle C disposal facility based on analytical data results (totals, TCLP, etc.) in accordance with North Carolina Hazardous Waste Section “Contained-in” Policy for soil contaminated with Listed Hazardous Waste. The excavation will be backfilled with clean soils and the area of the excavation will be returned to similar conditions prior to excavation activities.
One advantage of source area soil excavation is that no additional confirmatory soil sampling will be required post-excavation since soil quality data has already been collected defining the limits of the excavation. A disadvantage of the soil excavation option is that excavated soil must be transported off-site to an appropriate landfill/disposal facility in accordance with the waste classification based on analytical results of samples collected from the excavated soil, with a portion of the soil requiring disposal at a Subtitle C facility.
Village Laundry DC410034 Evaluation of Remedial Measures
3 | P a g e Evaluation of Remedial Measures
1) Practical Considerations for Implementing the Technology: The excavation area is moderately accessible and the presence of existing structures such as on-site utility poles and the brick building on the Sherrill property can be relocated or demolished to accommodate excavation requirements. Adjacent properties may be affected by the heavy flow of truck traffic carrying excavated soils off-site. Mr. Sherrill’s property will be affected for staging purposes of impacted soils. Upon excavation completion, the excavation will be backfilled with clean fill and restored to previous conditions with moderate interruption to immediate and adjacent property activities. Compaction tests will be performed in the area currently containing asphalt such that new asphalt can be installed properly. Grass seed and straw will be spread in the area which currently contains grass.
The activity will require interruption to the One Wok and Grill/Village Laundromat’s back parking lot and limited interruption to the Sherrill property given the building will be demolished. Christmas trees are sold on the Sherrill Property in late November and December each year, other than late November and December the Sherrill property is unoccupied.
2) Operation & Maintenance (O&M) Requirements: Excavation will be a one-time activity with no O&M requirements expected.
3) Risks and Effectiveness of the Proposed Remediation: Contaminated soils will be excavated and removed as described above to a depth of 12 ft bgs (static water level). Confirmation soil samples will not be collected as the area to be excavated has already been delineated to applicable SSTLs using existing soil quality data. Soil samples will not be collected from the base of the excavation as the base will be within the water table and saturated samples would not be representative of soil quality.
4) Long Term Reliability and Feasibility of Engineering and Institutional Controls: By removing the soil source of COC contamination to below the SSTLs, the soil remedial action will be considered complete and a success. Furthermore, groundwater quality beneath and downgradient of the excavation will improve over time. Future excavation should not be required thereafter.
5) Technical Feasibility of the Proposed Method: All work will be conducted using excavators and backhoes. Access to the excavation area will require removal of the brick building on the Sherrill property and relocating the power pole currently located in the middle of the excavation. In addition, technical consideration will be necessary to account for the depression in the ground adjacent to the excavation where the basement of the brick building was located.
Village Laundry DC410034 Evaluation of Remedial Measures
4 | P a g e Evaluation of Remedial Measures
The anticipated 12-foot depth of the proposed excavation is accessible using standard equipment. By immediately targeting and removing source soils exceeding the SSTLs, the soil remedial action will be considered complete and a success.
6) Estimated Time Required to Achieve Established SSTLs: An estimated 4-5 weeks will be required to complete the excavation, backfilling and site restoration. The following items affect duration:
o Number of roll-offs available to contain and transport the excavated soil; and, o The area which can be used for staging roll-offs. If the area formerly containing
the red brick building on the Sherrill property can be “filled in” more roll-offs can be used for transporting soil.
7) Cost Effectiveness of Proposed Remediation When Compared to Other Remediation Alternatives: Hazardous and non-hazardous soils designation and pricing associated with each designation was determined using existing soil quality data collected to date. Soils that are hazardous (approximately 540 tons) will be disposed at the US Ecology Michigan facility in Belleville, MI. Soils can be disposed at this location if they are above or below the Land Disposal Restriction values (60 parts per million for PCE).
Soils that are non-hazardous (approximately 1,760 tons) will be disposed at Evo Corporation in Winston-Salem, NC. The estimated cost for the excavation, transport and disposal of hazardous and non-hazardous soils offsite is between $450,000 and $500,000.
8) Community Acceptance: Since excavation will remove the primary source of soil COC contamination, it is anticipated that the community would be supportive of this remediation technology; however, disapproval may be encountered as the truck traffic for transporting soils will be heavy in an area that is already congested (nearby grocery store, fast food and strip mall) and has single lane roads at Hunt Club Drive and Francis King Street.
1.2 Excavation with Steam Distillation Treatment
The excavation component of this option is the same as excavation listed under section 1.1, with the exception that excavated soils deemed hazardous based on the analytical results of samples collected from the excavated soils and compared against the North Carolina Hazardous Waste Section “Contained-in” Policy, will be treated on-site using steam distillation to reduce contaminant concentrations such that they can be disposed as non-hazardous material at a subtitle D landfill (Evo Corporation in Winston-Salem, NC). As documented in the excavation and off-site disposal option, the approximate volume of PCE affected soils that exceed 14 mg/kg, and is therefore considered a hazardous waste, is approximately 540 tons. This option assumes that the 540 tons of excavated hazardous soils will require steam distillation treatment (additional
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soils may need to be treated depending on soil analytical results). Soils will be treated until they are within contaminant concentration limits to be accepted by a subtitle D landfill. The total area to be excavated is estimated at approximately 3,945 square feet, or 1,750 cubic yards (2,300 tons) assuming a depth of 12 feet.
The advantage of this remedial activity is not incurring additional expenses to dispose of excavated soil classified as hazardous, since soils deemed to be hazardous will be treated using steam distillation to reduce concentrations to below hazardous levels. The disadvantages include:
• The additional time to treat the soil to reduce concentrations to non-hazardous will be significantly longer.
• Higher contaminant concentrations may require multiple treatments and analysis of soils post treatment. The multiple treatments increase project duration which increase costs.
• Additional space and room for vehicles to re-locate staged soils for treatment and testing will be necessary. Multiple roll-offs will be staged on-site as part of these efforts.
• The steam distillation process creates odors as a result of the process. These odors may be found unfavorable to the surrounding public.
1) Practical Considerations for Implementing the Technology: The excavation area is moderately accessible and the presence of existing structures such as on-site utility poles and the brick building on the Sherrill property can be relocated or demolished to accommodate excavation requirements. Adjacent properties may be affected by the heavy flow of truck traffic carrying excavated soils off-site. Mr. Sherrill’s property will be affected for staging purposes of impacted soils and to perform the steam distillation treatment process. Upon excavation completion, the excavation will be backfilled with clean fill and restored to previous conditions with moderate interruption to immediate and adjacent property activities. Compaction tests will be performed in the area currently containing asphalt such that new asphalt can be installed properly. Grass seed and straw will be spread in the area which currently contains grass.
The activity will require interruption to the One Wok and Grill/Village Laundromat’s back parking lot and limited interruption to the Sherrill property given the building will be demolished. Christmas trees are sold on the Sherrill Property in late November and December each year, other than late November and December the Sherrill property is unoccupied.
2) Operation & Maintenance (O&M) Requirements: Excavation will be a one-time activity with no O&M requirements expected. The steam distillation process of soils
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deemed to be hazardous based on analytical results will require additional time to be treated to below hazardous concentrations.
3) Risks and Effectiveness of the Proposed Remediation: Contaminated soils will be excavated and removed to a depth of 12 ft bgs (static water level). Confirmation soil samples will not be collected as the area to be excavated has already been delineated to applicable SSTLs using existing soil quality data. Soil samples will not be collected from the base of the excavation as the base will be within the water table and saturated samples would not be representative of soil quality.
High concentrations of COC soils could potentially require multiple treatments prior to disposing at a subtitle D facility.
4) Long Term Reliability and Feasibility of Engineering and Institutional Controls: By removing the soil source of COC contamination to below the SSTLs, the soil remedial action will be considered complete and a success. Furthermore, groundwater quality beneath and downgradient of the excavation will improve over time. Future excavation should not be required thereafter.
5) Technical Feasibility of the Proposed Method: All work will be conducted using excavators, backhoes and steam distillation equipment. Access to the excavation area will require removal of the brick building on the Sherrill property and relocating the power pole currently located in the middle of the excavation. In addition, technical consideration will be necessary to account for the depression in the ground adjacent to the excavation where the basement of the brick building was located.
The anticipated 12-foot depth of the proposed excavation is accessible using standard equipment. By immediately targeting and removing source soils exceeding the SSTLs, the soil remedial action will be considered complete and a success.
6) Estimated Time Required to Achieve Established SSTLs: An estimated 5-6 weeks will be required to complete the excavation, backfilling and site restoration. The following items affect duration:
o Number of roll-offs available to contain and transport the excavated soil; and, o The area which can be used for staging roll-offs. If the area formerly containing
the red brick building on the Sherrill property can be “filled in” more roll-offs can be used for transporting soil.
7) Cost Effectiveness of Proposed Remediation When Compared to Other Remediation Alternatives: The estimated cost for excavation with steam distillation treatment is between $300,000 and $350,000. The non-hazardous (approximately 2,300 tons) soils
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will be disposed at Evo Corporation in Winston-Salem, NC. The treatment of the hazardous soils encountered during the excavation make will make this option more cost effective than the excavation with no treatment option. Depending on magnitude of contaminant concentrations, several treatments may be required. The additional treatments are included within the price; however, the additional time for more than one treatment is not included within the price.
8) Community Acceptance: Since excavation will remove the primary source of soil COC contamination, it is anticipated that the community would be supportive of this remediation technology. However, the use and staging of steam distillation treatment equipment, stockpiled contaminated soil onsite and the constant flow of trucks hauling away soil may not appeal to the community from an aesthetic point of view. The truck traffic for transporting soils will be heavy in an area that is already congested (nearby grocery store, fast food and strip mall) and has single lane roads at Hunt Club Drive and Francis King Street.
The steam distillation process creates odors as a result of the process. These odors may be found unfavorable to the surrounding public/community.
1.3 In-Situ Soil Blending
In-situ soil blending involves the use of an in-situ mixer to distribute chemical amendments throughout the soil. The mixer is capable of mixing dry and saturated soils to a depth of 18 feet below ground surface (bgs) which would affect unsaturated soils from 0-12 feet bgs and saturated soils from 12 to 18 feet bgs; however, for the purposes of this remedial evaluation, blending would only occur to a depth of 12 feet bgs which is consistent with the depth of affected soils. In-situ blending will allow for direct contact between the chemical amendments and the impacted soil. Activated persulfate, Potassium Permanganate, ABC+ and Daramend were evaluated as soil blending options. Activated persulfate and Potassium Permanganate are oxidizers. ABC+ is a combination of carbon substrate, nutrients and zero valent iron (ZVI) that enables a direct chemical reduction and promotes biological reduction. Daramend uses ZVI, coupled with anaerobic bioremediation for the effective treatment of chlorinated solvents. Physical, chemical, and biological processes combine to create an extremely reduced environment that stimulates chemical and microbiological dechlorination of otherwise persistent chlorinated compounds. For costing purposes, under number 7 of section 1.3, Potassium Permanganate was determined to be the most appropriate selection for in-situ soil blending at the site.
After removing asphalt on the east side of the excavation, soil blending would allow contaminated soils within the source area shown in Figure 3 of the Soil Remedial Action Plan to be treated on site. The asphalt would be removed and properly disposed. Typically, the addition
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of an amendment as part of a soil blend would require excavating and removing the upper three feet of soil to allow for displacement of the additional volume to fill. However, the additional volume created due to the application of the amendment will be used to “fill in” the depression left following the demolition and removal of the approximate 2,100-square foot red brick building on the Sherrill property. It is anticipated that approximately 52,000 pounds of Potassium Permanganate at a dose of 10 grams per kilogram would be mixed with the contaminated soil. The actual Potassium Permanganate amount will be determined based on analysis of soil samples collected for total oxidant demand prior to performing the soil blending activities. Portland cement (3 weight percent or 78 tons), would also be mixed with the treated soil to regain soil strength in the event future building might occur where the fill is placed on the Sherrill property or within the excavation area.
One disadvantage is that Potassium Permanganate is a relatively new technology for treatment of unsaturated contaminated soils (which is the target contamination reduction zone). According to Redox Tech, it is critical to use plenty of water during the process to affect unsaturated soils. An additional disadvantage is that confirmation soil samples will be necessary to demonstrate that SSTLs have been met throughout the treatment area following the blending activities. Post treatment confirmation soil samples will be collected in accordance with applicable confirmatory sampling guidance specific to in situ soil remedial actions.
1) Practical Considerations for Implementing the Technology: The soil blending/excavation areas are moderately accessible and the presence of existing structures such as on-site utility poles or the red brick building on the Sherrill property can be relocated or demolished to accommodate blending/excavation requirements. Adjacent properties will not be impeded by the blending/excavation activities other than for staging purposes on the Sherrill property.
2) Operation & Maintenance (O&M) Requirements: Soil blending will be a one-time activity with no O&M requirements expected.
3) Risks and Effectiveness of the Proposed Remediation: Asphalt on the east side of the excavation will be removed and disposed appropriately. Remaining contaminated soils will be blended using an excavator equipped with a mixing tool to a depth of 12 ft bgs. There is a good possibility that blending will weaken the bearing capacity of soils during/after the treatment. Thus, Portland cement will be added for soil stability and strength. Post treatment confirmation soil samples will be collected in accordance with applicable confirmatory sampling guidance specific to in situ soil remedial actions to confirm soils are less than the SSTLs.
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4) Long Term Reliability and Feasibility of Engineering and Institutional Controls: Potassium Permanganate will oxidize PCE, TCE and VC into harmless compounds. Soil analysis after blending will be required to confirm that soils have been remediated to below the SSTLs. Boring locations and depths would need to be established within the source area for collecting soil samples post treatment.
5) Technical Feasibility of the Proposed Method: All work will be conducted using an excavator equipped with mixing tool and backhoe(s). Access to the excavation area will not be an issue after the power pole and red brick building on the Sherrill property have been relocated and removed, respectively.
By immediately targeting and remediating the known source of contamination to 12 ft bgs, future contamination issues in the groundwater will be reduced. Only the asphalt layer on the east side of the excavation will be removed from the site and properly disposed. The remaining soil beneath the asphalt will be treated in the blending process and kept within the affected area.
6) Estimated Time Required to Achieve Established SSTLs: An estimated 4 to 5 weeks will be required to complete the soil blending.
7) Cost Effectiveness of Proposed Remediation When Compared to Other Remediation Alternatives: The estimated cost for soil blending Potassium Permanganate and adding Portland cement is approximately $300,000.
8) Community Acceptance: The soil blending process will require limited asphalt removal with the remaining contaminated soil being treated on-site and in-situ. Soil blending with Potassium Permanganate may cause temporary purple staining in the soils and immediate surrounding area. The staining is temporary and will disappear over time. The temporary purple staining could cause concern to the community.
Potassium Permanganate, when properly used at the recommended product application concentrations, is not harmful to human health or the environment.
1.4 Injection/EOS-VOS
EOS-VOS is a soybean oil emulsion that will be injected at multiple locations directly above the water table in the soil source area depicted in Figure 3 (of the Soil Remedial Action Plan) where soils exceed the SSTLs. Once injected into the subsurface at properly spaced locations within the source area, the emulsion will provide a two foot vertical section immediately above the water table (10-12 feet bgs). The EOS-VOS includes nutrients, pH buffer and microbes that promote reductive dechlorination of impacted waters percolating vertically through the soil within the source area. However, impacted soils above the SSTL would remain in place above
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the application interval which may act as a contaminant source for vapor intrusion to future structures in the area.
The use of EOS-VOS will allow for all soil to be kept on-site. The work would require injections using Geoprobe technology. EOS-VOS is a relatively new product for treating unsaturated zones (the product has been used at a few sites with success for treating unsaturated zones) but it is still considered somewhat unproven at this time. The costs may be prohibitive due to the high purchase price of the product and the number of injection points given the size of the treatment area. Costs for AECOM labor, equipment and regulatory permitting requirements were not factored in to this technology’s evaluation.
1) Practical Considerations for Implementing the Technology: EOS-VOS injection is much less invasive than the other technologies evaluated. Geoprobe injections will deliver the product below grade without disturbing the property significantly. Impacted soils within the source area will remain in place.
2) Operation & Maintenance (O&M) Requirements: Geoprobe technology will deliver the EOS-VOS below the subsurface by injection. Additional injections may be required after one year, pending groundwater analytical results showing reductive de-chlorination.
3) Risks and Effectiveness of the Proposed Remediation: The EOS-VOS will act as a permeable reactive zone and prevent contamination from leaching and migrating vertically through the subsurface to the groundwater table. This technology is relatively new and does not directly address the source of COC contamination (it mitigates migration of COCs into the water table and downgradient from the site).
4) Long Term Reliability and Feasibility of Engineering and Institutional Controls: The EOS-VOS does not actively address the COC soil contamination; rather it will reduce contaminated water above the EOS-VOS layer as it contacts the emulsion during percolation from the ground surface to the water table. Additional injections may need to be performed after one year.
5) Technical Feasibility of the Proposed Method: The EOS-VOS will be installed using Geoprobe technology. Given past completed Geoprobe sampling at the site, installations should not be problematic. After one year, additional injections may need to be performed using the same method.
6) Estimated Time Required to Achieve Established SSTLs: An estimated 6 weeks will be required to complete installation. SSTLs will not be achieved for soils as they will not be removed. After installation, groundwater will need to be analyzed to confirm reduction
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of contaminant concentrations to below the applicable groundwater vapor intrusion action levels.
7) Cost Effectiveness of Proposed Remediation When Compared to Other Remediation Alternatives: The cost for the EOS-VOS product is approximately $300,000 to $350,000. This cost does not include analytical costs to confirm reductive de-chlorination within the groundwater.
8) Community Acceptance: Compared to other alternatives within this SRAP, EOS-VOS installation by injection is the least invasive remediation technology. There should be no issues with community acceptance as the ground surface will be disturbed minimally. Adjacent properties will not be significantly impacted by the work.
1.5 Soil Vapor Extraction
Soil Vapor Extraction (SVE) involves applying a vacuum through extraction wells to create a pressure/concentration gradient that induces gas-phase volatile contaminants to partition from affected soils and be removed via a long-term treatment system. Depending on local and state air discharge regulations, the gas leaving the soil may be treated to recover or destroy the contaminants. Vertical SVE points would be installed and screened above the water table (12 feet bgs) to minimize entrainment of water from the saturated zone. Contaminated soil vapor would be extracted by using regenerative blowers or similar vacuum pumps. The area to treat is outlined in Figure 3 of the Soil Remedial Action Plan.
SVE has been implemented successfully at other DSCA sites maintained by AECOM and is a proven technology for this type of in-situ vadose zone remediation. The installation will require AECOM to be on site continuously during the drilling, trenching, equipment installation, etc. Unlike the other technologies evaluated, a building and discharge permit for effluent air from City of Greensboro may be required prior to system operation. Given the high clay content in the subsurface soil, SVE effectiveness may be limited. A pilot study should be performed to determine system effectiveness prior to installation, as well as design specifics such as radius of influence and blower/pump sizing. Additional power and O&M costs will be required to operate the SVE system successfully.
1) Practical Considerations for Implementing the Technology: SVE system installation will require significant time, coordination and preparation with the SVE installation subcontractor, Mr. Sherrill and AECOM due to immediate and long-term operation and coordination. Documented clay content within subsurface soils in the area of treatment will likely limit effectiveness. The pilot study may prove an SVE system will not be effective.
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2) Operation & Maintenance (O&M) Requirements: O&M visits during the life of the system (2 to 5 years) will be required to maintain system operation.
3) Risks and Effectiveness of the Proposed Remediation: Permits controlling air effluent contaminant concentrations may be required prior to system operation. The soil will be treated in place eliminating the need to remove soil from the site (other than drilling cuttings from installation of the SVE points). SVE technology is capable of addressing the COCs in the unsaturated zone without the need for more invasive, supplemental technologies.
4) Long Term Reliability and Feasibility of Engineering and Institutional Controls: SVE is a proven technology capable of reducing the COCs within the vadose zone. Since the COCs are finite (no more contamination is anticipated to occur), SVE operations can reduce the contamination sufficiently to meet SSTLs without the need for further remediation in the future. Sites with high clay content in the subsurface may limit SVE effectiveness. A pilot study will be required to determine system effectiveness prior to installation.
5) Technical Feasibility of the Proposed Method: SVE has been successful in meeting SSTLs for various other DSCA projects. Sites with high clay content in the subsurface may limit SVE effectiveness. A pilot study will be required to determine system effectiveness prior to implementation.
6) Estimated Time Required to Achieve Established SSTLs: An estimated 2 to 5 years will be required to achieve completion (including installation, operations/maintenance). System optimization during O&M visits may reduce the amount of operating time. Confirmation sampling would be necessary to demonstrate that impacted soils have been remediated to below the SSTLs prior to considering the treatment a success.
7) Cost Effectiveness of Proposed Remediation When Compared to Other Remediation Alternatives: It is estimated to cost a minimum $245,000 to install the SVE system equipment and components (wells, trench lines, etc.). It is also estimated to cost $50,000 per year of operation for O&M activities.
8) Community Acceptance: The system components can be housed in a shed made to look like a typical backyard shed. System noise abatement, odor and security can be maintained to prevent community aversion. Although this technology is viewed as a long-term remediation approach, the SVE system can be made to blend in and meet the community’s standards.
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1.6 Thermal Conductive Heating
Thermal Conductive Heating (TCH) is performed by heating the treatment area (shown in Figure 3 of Soil Remedial Action Plan) while a slight vacuum is applied to the subsurface to extract soil vapors. The heating of the soil is driven by temperature gradients created by steel TCH wells. Although it is a proven technology to treat chlorinated Volatile Organic Compound(s) (VOC) impacts, it is often implemented at larger scale soil and groundwater remediation projects due to its associated costs.
TCH requires above grade components thus limiting access to the area and nearby perimeter during treatment. Limited access to this area could affect seasonal work associated with Mr. Sherrill’s property and the rear parking lot of the One Wok and Grill and Village Laundromat.
1) Practical Considerations for Implementing the Technology: A TCH system installation will require multiple contractors to be on-site at various phases of construction. This will require significant time/coordination and preparation with all parties involved including Mr. Sherrill to complete the installation. Seasonal work associated with Mr. Sherrill’s property and the rear parking lot of the One Wok and Grill and Village Laundromat may also be disturbed due to construction/O&M activities. This technology will also require a large area due to above ground equipment limiting access to the treatment area and immediate perimeter.
2) Operation & Maintenance (O&M) Requirements: O&M visits will be required during the life of the remediation system operation which is anticipated to be up to 6 months.
3) Risks and Effectiveness of the Proposed Remediation: Permits controlling air effluent contaminant concentrations may be required prior to system operation. Exposure to soil vapors during O&M and exposure to high temperatures from the heating wells during system implementation are a safety concern. TCH is a proven technology that can meet SSTLs within 6 months of implementation without excavating/removing affected soils.
4) Long Term Reliability and Feasibility of Engineering and Institutional Controls: TCH is a proven technology capable of reducing the COCs within the unsaturated zone. Since the COCs are finite (no more contamination is anticipated to occur), TCH operations can reduce the contamination sufficiently to meet SSTLs without the need for further remediation in the future. Soil vapor recovery will be implemented alongside the TCH to control effluent COC concentrations. If necessary, Granular Activated Carbon (GAC) vessels can be installed to reduce effluent vapor COC concentrations released to the atmosphere. Breakdown components of the COCs will also be addressed by the TCH process and soil vapor extraction.
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5) Technical Feasibility of the Proposed Method: TCH is a proven technology to address chlorinated VOC contamination in the subsurface, but due to the high costs of implementation it is generally limited to larger scale operations.
6) Estimated Time Required to Achieve Established SSTLs: It is anticipated that the TCH remediation may meet the SSTLs in 6 months. Confirmation soil sampling would be necessary to demonstrate that impacted soils have been remediated to below the SSTLs prior to considering the treatment a success.
7) Cost Effectiveness of Proposed Remediation When Compared to Other Remediation Alternatives: It is estimated to cost approximately $650,000 to $700,000 to perform the TCH work.
8) Community Acceptance: Most of the system components will be constructed above ground, with the exception of the TCH wells. The system components will also take up a large area which will limit the space Mr. Sherrill will have to perform seasonal work on his property and parking behind the One Wok and Grill/Village Laundromat. System components will be exposed to public view which may not be acceptable to surrounding property owners.
APPENDIX B
APPENDIX C
APPENDIX D
APPENDIX E
Ambient Air Monitoring Plan
Prepared for: North Carolina Department of Environmental Quality Division of Waste Management, Superfund Section
INTRODUCTION AND BACKGROUND ................................................................................. 1
SCOPE OF WORK ....................................................................................................................... 1 Project Goals ....................................................................................................................... 1 Target Compounds .............................................................................................................. 2 Sampling Period and Frequency ......................................................................................... 4 Number and Location of Samplers ..................................................................................... 4 Sampling and Analysis Methods ......................................................................................... 6 Network Operations ............................................................................................................ 7 Data Management ............................................................................................................... 7
SCHEDULE & REPORTING ..................................................................................................... 7 List of Tables Table 1 Screening Levels for VOC’s ................................................................................... 2 Table 2 Summary of Proposed Monitoring .......................................................................... 3 Table 3 Proposed Monitoring Locations .............................................................................. 6 Table 4 Summary of Measurement Parameters ................................................................... 6 Table 5 Technical specification of Meteorological Sensors ................................................ 7
Ambient Air Monitoring Plan 1 of 7 Village Laundry
INTRODUCTION AND BACKGROUND
AECOM Technical Services of North Carolina, Inc. (AECOM) will undertake remediation activities at the Village Laundry, DC410034 located at 707 College Road (Site) in Greensboro, North Carolina. Contaminated soils will be blended with Potassium Permanganate. Historical soil quality data indicate that the primary chemicals of concern (COC) are:
Other volatile organic compounds (VOCs) commonly associated with dry cleaning operations, as well as some petroleum constituents were reported in small quantities.
This ambient air monitoring plan (AAMP) has been drafted to proactively demonstrate the effectiveness of the on-site emission controls and to prevent site activities from creating unacceptable air concentrations at the work site and/or beyond the boundaries of the remediation areas. Meeting these goals and objectives will be demonstrated by monitoring ambient air within the work site, and at the property line using a PPBv RAE. The PPBV RAE will provide real time measurements of total VOCs. Additional details concerning the use of the PPBv RAE and potential next steps if applicable are provided within the text of this document.
SCOPE OF WORK
AAMP elements include:
1. Project goals; 2. Target compounds; 3. Sampling period & frequency; 4. Number & location of samplers; 5. Sampling & analysis methods; 6. Network operations; and 7. Data management & reporting.
Project Goals
AECOM will monitor air quality at the site, and at the boundaries of the remediation area, to help protect the health of site workers and the general public. The goals of this monitoring effort are to:
• Document ambient air quality surrounding remediation activities throughout the remediation effort;
• Provide timely feedback to the site personnel so that on-site activities can be modified as necessary to maintain downwind concentrations at acceptable levels; and,
• Provide localized, continuous meteorological data to support the continuous ambient air monitoring and ambient air sampling.
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Target Compounds
The soils at the site have been extensively characterized. The primary target compounds in soil at the site are listed in Table 1. In the interest of being most conservative, the lower comparable values (highlighted in yellow) in Table 1 will be used for initial ambient air screening.
Table 1 – Primary Target Compounds in Soil Chemical
Abstracts No. Chemical
Name Maximum Soil
Concentrations Sample ID, and Sample Depth
79-01-6 TCE Maximum = 49.3 mg/kg Sample = SB-9
Depth = 4-5 ft bgs 127-18-4 PCE Maximum = 3800 mg/kg
Sample = SB-9 Depth = 4-5 ft bgs
156-59-2 cis-1,2-DCE Maximum = 49.3 mg/kg Sample = SB-9
Depth = 4-5 ft bgs 156-60-5 trans-1,2-
DCE Maximum = 0.033 mg/kg
Sample = SB-16 Depth = 0-1 ft bgs
75-01-4 Vinyl Chloride
Maximum = 4.9 mg/kg Sample = SB-9
Depth = 4-5 ft bgs 71-43-2 Benzene Maximum = 1.3 mg/kg
Sample = SB-12 Depth = 5-6 ft bgs
108-88-3 Toluene Maximum = 0.034 mg/kg Sample = SB-10
Depth = 0-1 ft bgs 100-41-4 Ethylbenzene Maximum = 0.0038 mg/kg
Sample = SB-10 Depth = 0-1 ft bgs
1330-20-7 Xylenes (total)
Maximum = 0.013 mg/kg Sample = SB-10
Depth = 0-1 ft bgs
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A – Occupational Safety and Health Administration B – Permissible Exposure Level
In addition, particulate matter (dust) emissions also are a potential concern, given the potential for asphalt removal, soil blending and other activities to generate dust emissions. The Primary National Ambient Air Quality Standards (NAAQS) are designed to be protective of human health and welfare. The 24-hour NAAQS for PM10 is an average of 150 micrograms per cubic meter (µg/m3).
The NAAQS values for PM10 will be used to develop conservative and protective real-time particulate matter action levels. If predicted ambient levels of constituents in air exceed the screening levels, it does not necessarily indicate a problem, but rather triggers a more in-depth review.
Table 2 - Summary of Proposed Monitoring
Constituent of Concern Collection Methodology Analytical Methodology
VOCs Continuous PPBv RAE Monitoring
Total VOC via photoionization
Benzene Hand aspirating pump and Dräger tube
Colormetric tube; standard deviation of 15%
Vinyl Chloride Hand aspirating pump and Dräger tube
Colormetric tube; standard deviation of 15-20%
PM10 Portable Continuous PM10
Monitoring Light Scattering Technology
A PPBv RAE will be used to monitor ambient air quality for total VOCs. Readings will be collected at the property line throughout the day. If results from the PPBv RAE exceed 1 ppm for longer than 1 minute a Dräger tube specific to vinyl chloride and benzene will be used to determine if VOCs detected by the PPBv RAE are the result of benzene or vinyl chloride. The PPBv RAE meets or exceeds the OSHA PEL for each constituent found in onsite soils. PEL’s for each constituent are displayed in Table 1.
In addition, the following meteorological parameters will be monitored:
The data from the meteorological station will be logged via Campbell Scientific CR800 (or equivalent) data logger. Data will be used to determine upwind and downwind locations, should wind directions shift during a sampling event. A percent downwind/upwind will be applied to constituents resultant concentrations as listed in Table 1.
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The Thermo Scientific Model ADR1500 Dust Monitor utilizes the highly sensitive light-scattering photometer (nephelometer) technology. The intensity of the light scattered by airborne particles passing through the sensing chamber is linearly proportional to their concentration. The ADR1500 incorporates a temperature and relative humidity (RH) sensor coupled with an internal heater to mitigate the positive bias with elevated ambient RH. Additionally, the flow control is truly volumetric and is maintained through digital feedback of the onboard barometric pressure sensor, temperature sensor and calibrated differential pressure across a precision orifice. The principles of true volumetric flow, as incorporated by the ADR1500, result in an accurate sample volume and precise particle cut-point. This optical configuration produces optimal response to particles, providing continuous measurements of the concentrations of airborne particles for total particulate and cut-points ranging from PM10 down to PM1. The measured concentration of particulate matter is displayed in real-time on the two-line LCD readout display.
Communications options are available for USB, RS-232, analog and wireless capability.
Sampling Period and Frequency
Remediation work is scheduled to begin in Fall of 2017 and will be completed in approximately four to five weeks. AECOM will collect continuous PM10 data and meteorological data for the duration of the soil blending and associated management and handling of impacted media at the site.
AECOM will collect readings from the PPBv RAE at the property line. Based on the results from the PPBv RAE, samples may be collected via Dräger tube and analyzed for vinyl chloride and/or benzene. The location of where blending activities are taking place will affect where readings are collected via PPBv RAE. For example, if the blending area is known to have high soil contaminant concentrations more frequent monitoring will occur. Oppositely, if the area has low concentrations less frequent monitoring may occur.
PM sampling will be conducted for no less than two days before the blending activities begin. VOC monitoring will be performed at least once before the start of the blending as a check of the monitoring systems and procedures, and to generate baseline data.
Location of Monitoring
Monitoring will occur daily at four locations near the perimeter of the property line for the Sherrill and Village Laundry properties (e.g., NE, SW, NW, and SE of blending activities). Meteorological data will be collected at one location. AECOM will utilize PPBv RAE data at the four locations described in the below Table 3. The monitoring locations were selected based on the prevailing winds at the Piedmont Triad International Airport (Airport) which is approximately 2.5 miles west of the Site.
Wind speed and wind direction data from the Airport were utilized to generate a wind rose for the area. This wind rose from the Piedmont Triad International Airport Greensboro Airport is shown
Ambient Air Monitoring Plan 5 of 7 Village Laundry
below in Figure 1. The predominant winds are from the southwest. Therefore, the greatest air quality impacts from remediation activities are expected to occur to the northeast. The secondary peaks in frequency are from the northeast.
Figure 1. Wind Rose for Greensboro, NC Source: http://www.nc-climate.ncsu.edu/windrose.php
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Table 3 - Proposed Monitoring Locations
Site/Station ID Approximate Location Monitoring Equipment
Station - 1 (NE edge of Site)
Downwind based on prevailing winds – See Figure 1.
Met station, Thermo ADR 1500 Portable PM10
PPBv RAE
Station - 2 (SW edge of Site)
Downwind location based on secondary prevailing winds. PPBv RAE
Station - 3 (NW edge of Site)
Upwind based on prevailing winds – See Figure 1.
Thermo ADR 1500 Portable PM10
PPBv RAE
Station - 4 (SE of edge of Site)
Upwind location based on secondary prevailing winds. PPBv RAE
Sampling and Analysis Methods
Proposed AAMP sampling and analysis methods are summarized in Table 4.
Table 4 - Summary of Measurement Parameters
Measurement Parameter Frequency Sampling Method Analytical Method
If downwind dust levels exceed pre-set criteria or visible dust emissions are observed, water sprays or other measures will be used to reduce dust emissions. If dust emissions are controlled, air emissions of other contaminants will also be controlled. The results of particulate monitoring will be compared to the OSHA Permissible Exposure Limit (PEL) of 5 mg/m3 for PM10 dust.
The action level for perimeter particulate levels (from the real-time monitoring stations) is 100 ug/m3 averaged over a rolling 60 minute period. This action level is significantly lower as compared to the 150-ug/m3 PM10 standard on a 24-hour average and the OSHA standard of 5 mg/m3.
The portable meteorological station will be used to collect wind direction, wind speed, precipitation, and temperature data on a tripod at a height of 18 feet above ground surface. The sensors for the meteorological monitoring component of the program have been selected to meet or exceed U.S. EPA monitoring criteria. The data will be augmented, as needed, with meteorological data from the nearest National Weather Service monitoring site or an equivalent monitoring site. Table 5 summarizes the technical specifications of the proposed meteorological sensors.
Ambient Air Monitoring Plan 7 of 7 Village Laundry
Table 5 -Technical specification of Meteorological Sensors
Meteorological Data Ambient Temperature Accuracy ± 1.8°F Wind Speed Accuracy ± 0.4 mph Wind Speed Threshold Limit: 0.6 mph Wind Direction Accuracy ± 5 degrees Wind Direction Resolution: 1 degree Precipitation Accuracy ± 0.1 inches Completeness > 90% of 5-minute averages for each event
°F – Fahrenheit; Mph – miles per hour
Network Operations
Experienced personnel from the AECOM-Morrisville office will perform initial set-up and calibration of the equipment at the site. Subsequently, trained site staff will perform routine on-site air monitoring activities.
The action levels for PM10 concentrations will be used by site personnel to initiate additional particulate controls in the event that unusual conditions (such as high wind speeds or gusty winds) render normal controls inadequate to mitigate particulate emissions from blending activities. The air monitoring station data loggers will be programmed to compare current PM10 concentration readings to the appropriate action level value for the corresponding averaging period. If concentrations above the action level are detected, the data logger will immediately initiate a text message notification that will be transmitted to the cell phones of on-site personnel.
Data Management
The data reported from the laboratory will be evaluated by AECOM. Continuous on-site monitoring data will be maintained by AECOM in a database. In general, the goal is to have 90% or more of the attempted monitoring events result in valid data. Field sampling data, such as initial PPBv RAE readings, or elapsed time readings will be manually recorded in a logbook. A single logbook will be used to document all sampling during the study, and the field technician(s) will make entries at the time of sampling.
SCHEDULE & REPORTING
The project duration is estimated to be four to five weeks. Data summaries will be prepared weekly and distributed by email. If necessary, the continuous monitoring data can be prepared for a formal submittal, upon request. Supporting information will be included in a final report documenting blending activities.
