New York State Department Of Environmental Conservation Active Industrial Uniform Site

Posted on June 16, 2015

Client: New York State Department Of Environmental Conservation
Project Type: Active Industrial Uniform Site

Major Components

  • Performance Monitoring Services

Project Description

Introduction

D&B Engineers and Architects, P.C. was retained by the New York State Department of Environmental Conservation (NYSDEC) to provide performance monitoring services in connection with the Active Industrial Uniform Site. D&B began monitoring site performance on July 1, 2006 and will continue monitoring the site for 36 months.

The Active Industrial Uniform Site is a former dry cleaning and laundry facility located on Montauk Highway in the Village of Lindenhurst, Suffolk County, New York. The site is approximately 1/2 acre in size and is currently occupied only by the groundwater treatment facility.

Site Background

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  • The Active Industrial Uniform Site was used as a commercial laundry from 1945 to 1993. Dry cleaning operations reportedly started in the 1970s and was discontinued in 1987.
  • By May of 1994, all site operations had ceased, and site buildings were demolished by February 1995. Currently, the site is vacant except for the building and equipment to treat the groundwater, and is entirely fenced with a locked gate.
  • Remedial investigations have been conducted at the Active Industrial Uniform site since 1987. A soil vapor extraction (SVE) system, installed as an interim remedial measure (IRM), began operation in 1991. The goal of the IRM was to remove soil contamination on-site.
  • The NYSDEC approved a Remedial Investigation and Feasibility Study (RI/FS) in October 1993. The RI/FS determined that soil on site and the groundwater between the site and Little Neck Creek were contaminated. A shallow plume, with concentrations of tetrachlorethene (PCE) as high as 20 ppm, was identified heading southwest toward Little Neck Creek, approximately 800  feet away. Little Neck Creek discharges into the Great South Bay, approximately 4,200 feet south.
  • The original design concept outlined in the Record of Decision (ROD) called for two groundwater recovery wells; one on-site and one off-site, 100 yards downgradient, each pumping at 60 gallons per minute (gpm). Results of the design investigation required a modification to the scope of work for remediation.
  • When contamination of 10 parts per million (ppm) PCE was found in the groundwater approximately three blocks away, the scope of work was modified to include two groundwater recovery wells, one well on-site and one well three blocks away, each pumping at 100 gpm.
  • The NYSDEC issued a ROD for the site on March 26, 1997, which provided for the installation of a groundwater extraction and treatment system to remediate the spill.

Groundwater Treatment System Descriptionaiu2

The system to treat the contaminated groundwater extracted by the extraction wells includes air stripping for VOC removal with a packed tower stripper, and carbon adsorption of the VOCs from the exhaust gas prior to the release to the atmosphere. The system also includes controls and instrumentation to completely automate the treatment process and an autodial system to report any alarms or malfunctions.

The removal of total VOCs from the extracted groundwater is achieved by air stripping. The objective of the air stripping system is to reduce total VOC concentrations in the extracted groundwater to meet the requirements of 40 CFR Part 469 and discharge criteria established by the Village of Lindenhurst. The air stripper is a packed tower stripper where the VOC-contaminated water flows down and across the packing. At the same time, fresh air is blown into the stripper, bubbling up through the spaces in the packing and transferring volatile solutes from the liquid to the vapor phase. The stripper is designed to remove more than 99% of the tetrachloroethene (PCE) from the extracted groundwater.

Since the air stripper does not destroy the VOCs but actually transfers them from the water to the air, granular activated carbon was selected for the treatment of the air stripper exhaust gas. The carbon adsorption system will remove more than 99% of the contaminants present in the air stripper exhaust gas before the air is finally released to the atmosphere.

The treated groundwater will be discharged to the existing Village of Lindenhurst storm sewer system. The discharge of treated groundwater from the system will be in accordance with all Village of Lindenhurst requirements.

Performance Monitoring and Site Management

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Site management activities performed by D&B for the Active Industrial Uniform site include providing performance monitoring services for a period of 36 months for the site groundwater extraction and treatment system. The scope of performance monitoring services is as follows:

  • Samples of air stripper combined influent and effluent are collected once per month; combined influent and effluent samples are analyzed for TCL VOCs and combined influent is analyzed for Target Analyte Test (TAL) inorganics and pH. Effluent samples are analyzed for TAL inorganics on a quarterly basis.
  • Collection and analysis of samples from each of the extraction well influent pipe sample taps and at the “mid-fluent” sample tap between the two air strippers once every 3 months. Influent samples are analyzed for VOCs, TAL inorganics and pH. The “mid-fluent” samples are analyzed for VOCs.
  • Effluent samples are analyzed semiannually for pH, chemical oxygen demand, alkalinity, total suspended solids and total dissolved solids. Additionally, effluent samples are monitored semiannually by field test for dissolved oxygen, conductivity, turbidity and chlorine.
  • Collection and analysis of vapor phase influent, “mid-fluent” and effluent samples from the carbon adsorption vessels, once per month. Influent, “mid-fluent” and effluent samples are analyzed for VOCs.
  • Collection and analysis of samples from each of the 11 groundwater monitoring wells once every 3 months. Groundwater samples are analyzed for VOCs and pH.
  • Inspection and routine preventive maintenance of the pressure blower unit, once every 3 months.
  • Inspection and routine maintenance of the transfer pumps, once every 6 months.
  • Acid washing each of the packed air strippers once per year.

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