United States Environmental Protection Agency
Region V
POLLUTION REPORT

Subject: 

See POLREPs #1-7 for a full Site Description.

During the fall/winter of 2012, a network of extraction wells was installed that, along with the Multi-Phase Extraction (MPE) system, will be used to evacuate LNAPL identified in the site subsurface. 36 extraction wells were incorporated into the well network located toward the southwest corner of the site. Wells are 4-inch in diameter and placed to a maximum depth of 25 feet below ground surface. In addition to the extraction wells, two gas probes were installed on each side of the site (N,S,E,W) to be used for monitoring vapors and vacuum pressure.

The main components of the MPE system include a solids knockout tank, oil/water separation tank, bag-filters, carbon vessels, LNAPL storage tank, and a discharge line to the city storm sewers. A network of PVC piping connects the extraction wells to the MPE system and includes valves for adjusting flow rates and fittings to allow vacuum and gas monitoring. Connections to the PVC piping are reinforced HDPE dip-tubes that can be adjusted to different levels within the wells. The dip-tubes are capable of running to the bottom of the extraction wells and allow transportation of groundwater/LNAPL to the surface and down the PVC pipes to the MPE system for treatment.

Following installation of the MPE system, extraction/discharge piping was insulated and heat traced to allow operation of the system during winter months.

During the fall, a pilot test was schedule that would have allowed continuous running of the system, but during startup, it was discovered the MPE system was having difficulty separating LNAPL from the extracted groundwater. The small amount of LNAPL passing by the system oil/water separator was causing frequent filter and carbon media change-outs. Over the winter of 2012, CRA re-designed the MPE system to include different filters, media, and additional carbon treatment.
In March 2013, a second building was installed down-stream of the primary treatment building to house four additional carbon vessels and one additional effluent filter. Additional upgrades to the original MPE system included the addition of oil-absorbing filters and conversion of the first two treatment carbon vessels from activated carbon media to oil absorbing Organo-clay media. Installation and setup of the second treatment building was completed on March 18, 2013.

On March 20, 2013, EPA approved the Respondents’ Construction Certification Report (CCR), which effectively marks the construction complete milestone of the Removal. A copy of the report can be found under documents.

- Continue MPE system startup
- The MPE system will operate until extractable LNAPL has been recovered (up to 10 years).
- The CCR contains a program of operation and maintenance that will continue for the next several years.

- Transition from CERCLA to RCRA lead