Dormitory Authority – State of New York Underground Storage Tank Investigation and Remediation

Posted on January 11, 2010

Client: Renaissance Project, Inc.
Location: Ellenville, New York
Project Type: Underground Storage Tank Investigation and Remediation
Project Period: May 2009 - January 2010
D&B Project Manager: James J. Magda
Project Cost: $15,000

Project Description

Introduction

D&B Engineers and Architects, P.C. was retained by the Renaissance Project, Inc. (Renaissance) under its Environmental Term Contract with the Dormitory Authority State of New York (DASNY) to provide technical assistance during the remediation of petroleum contamination at the Renaissance Project facility located in Ellenville, New York. Renaissance was in the process of constructing a drug rehabilitation facility on the site when three underground storage tanks (USTs), formerly used to store heating oil, were discovered by the general contractor. As a result, the general contractor was directed to remove the USTs. During the removal, the general contractor discovered two of the USTs had leaked fuel oil. The New York State Department of Environmental Conservation (NYSDEC) Region III Office was notified of the petroleum releases and assigned two NYSDEC spill numbers to the property, Spill Nos. 0902465 and 0902473.

Prior to D&B’s involvement in the project, the general contractor was directing the remediation and over 2,500 cubic yards of soil were excavated and stockpiled on-site, and approximately 85,000 gallons of water were pumped from the excavation and transported off-site for disposal.

D&B’s first action after being retained by Renaissance was to stop all ongoing remedial activities being performed by the general contractor. D&B’s primary objective was to provide Renaissance with guidance on the most efficient and cost-effective method of completing the remediation and to close out the open NYSDEC spills. To accomplish this objective, D&B first met with the NYSDEC Region III Case Manager to develop a plan of action for spill closure. Based on this meeting, D&B drafted a work plan detailing the agreed approach which included: a subsurface investigation, dewatering of the excavation areas, collection of post-excavation confirmatory soil samples and the characterization of the soil stockpile. D&B closely monitored all site activities associated with the approved work plan to ensure technical adequacy and quality of work.

Subsurface Investigation

Prior to proceeding with any additional remedial activities at the site, a subsurface investigation was performed to better define the extent of contamination associated with the leaking USTs. A total of twelve soil borings were advanced at various locations throughout the site using direct-push (Geoprobe) drilling techniques. Soil and/or groundwater samples were collected for laboratory analysis from select boring locations based on field observations. Samples were analyzed for volatile organic compounds (VOCs) and semi volatile organic compounds (SVOCs) utilizing the NYSDEC Spill Technology and Remediation Series (STARS) target compound list.

D&B prepared a summary of the contaminant concentrations compared to applicable standards, criteria, and guidance values (SCGs). No VOCs or SVOCs were detected in any of the subsurface soil samples at concentrations in excess of applicable SCGs. Furthermore, no VOCs or SVOCs were detected in any of the groundwater samples at concentrations in excess of applicable SCGs.

Building upon D&B’s initial assessment of the site and the results of the subsurface investigation, D&B met with Renaissance, NYSDEC and DASNY project representatives to discuss recommendations to close the two spills and evaluate alternatives to minimize project costs.

Construction Water Management

Prior to D&B’s involvement in the project, groundwater and surface water runoff entering the excavation areas was routinely pumped and transported off-site for disposal using a vacuum truck by the general contractor. This initial approach to managing the water was very costly. Based on the results of the subsurface investigation, D&B developed a very cost-effective water management plan that detailed the steps required to collect, characterize, and discharge construction water on-site. The construction water management plan was approved by the NYSDEC and subsequently implemented. The plan resulted in a significant reduction in transportation and disposal costs.

Post-Excavation Confirmatory Sampling

Following dewatering of the excavation areas, D&B developed a post-excavation confirmatory soil sampling plan. The plan utilized the analytical data generated as part of the previously completed subsurface investigation. As a result, the total number of post-excavation confirmatory soil samples required to document removal of petroleum-impacted soil was significantly reduced, further reducing the overall cost of the project.

A limited number of excavation sidewall and bottom samples were collected and analyzed for VOCs and SVOCs. No VOCs or SVOCs were detected in any of the samples at concentrations in excess of applicable SCGs. Based on the results of the subsurface investigation and post-excavation confirmatory soil sampling data, backfilling of the excavation areas was approved by NYSDEC.

Soil Stockpile Characterization Program

Prior to D&B’s involvement in the project, approximately 2,500 cubic yards of soil were excavated and stockpiled on-site by Renaissance’s general contractor. To determine the most efficient and cost-effective disposal options for the soil stockpile, D&B developed a soil characterization program. The plan was approved by the NYSDEC and subsequently implemented at the site.

The soil stockpile was graded to a uniform thickness. A network of equally spaced grids was established across the pile. A track-mounted direct-push Geoprobe Unit was then used to complete two soil borings within each grid location. Soil recovered from each of the borings was combined to form a composite sample representing the grid. The samples were then analyzed for VOCs and SVOCs. Analytical results were compared to Recommended Soil Cleanup Objectives for Fuel Oil Contaminated Soil and were evaluated relative to the SCGs on a grid-by-grid basis. No VOCs or SVOCs were detected in any of the soil samples at concentrations in excess of applicable SCGs. However, the total VOC tentatively identified concentration for one grid location sample exceeded SCGs.

Based on the results of the soil stockpile characterization program, NYSDEC approved the stockpile for beneficial re-use on-site as backfill material, with the exception of one grid. As a result, the vast majority of the stockpiled soil was used as backfill, saving the client well over $20,000 in disposal fees.

NYSDEC Spill Closure

After backfilling the excavation areas, D&B prepared an underground storage tank closure report was prepared for the site. The closure report summarized all completed field activities and sample results, and provided recommendations for spill closure. Based on the information provided in the report, NYSDEC closed both spill numbers and indicated no further remedial activities were necessary at the site.

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