Update March 2010

Jet Grout Barrier Wall Completed!
Focus Shifts to Operable Unit 2

Operable Unit 1 (40 Willow Avenue)
National Grid and NYSDEC Reached a Major Milestone on the Final Major Phase of Remediation of OU-1 (40 Willow Ave. Sector) of Former Manufactured Gas Plant (MGP) Site.

The New York State Department of Environmental Conservation (NYSDEC) and National Grid (formerly KeySpan) have completed the installation of the jet grout barrier wall at the sector of the former manufactured gas plant site on which the gas holder and supporting facilities were located (the OU-1, 40 Willow Avenue parcel).  Quality assurance coring and hydrogeologic testing of select areas of the barrier wall have been completed, and the four walls have been certified by the Engineer-of-Record.  All site restoration activities have been completed and the jet grout and waste management contractors have demobilized from the site.

Field activities to monitor and study the potential for removing Dense Non-Aqueous Phase Liquid (DNAPL) from within the containment barrier were initiated in December 2009.  Pilot wells were placed within the holder foundation, adjacent to the former holder to evaluate soils just below the bottom of the holder foundation, and within coarse grained soils located at significant depths outside of the holder.  The next step is to perform a short-term recoverability test and analyze the results.  The following bullet points detail ongoing and future anticipated activities on the OU-1 site.
On-going activities:

  • Continued recovery testing and measurement of three (3) NAPL recovery wells within the jet grout barrier wall as part of the NYSDEC-approved NAPL recovery pilot test.
  • Continued monthly groundwater sampling within the Lynhurst Avenue #53 buffer zone as agreed to with the Lynhurst residents in the June 2009 public meeting and as required by NYSDEC and New York  State Department of Health (NYSDOH).

Future (two week look-ahead) activities:

  • Continue recovery testing and measurement of NAPL recovery pilot test wells at the concrete work platform within the jet grout barrier wall.
  • Finalize the Clifton OU-1 Construction Completion Report and submit to NYSDEC/NYSDOH.

Recently Completed Activities:

  • Installed three DNAPL recovery wells within the jet grout barrier containment walls.
  • Performed CAMP monitoring during the drilling and waste management activities.

Operable Unit 2 (25 Willow Avenue)

With the completion of the OU-1 barrier wall installation, focus has shifted to the remedial design investigation and remedial construction of OU-2.    OU-2 is the site of the former manufactured gas plant that previously operated at 25 Willow Avenue and was closed in 1957.  There also are two off-site areas that are located adjacent to OU-2 at 89 Willow Avenue and 1 Edgewater Street.  The remedial activities at OU-2 have progressed with the approval of the final remedial design work plan by NYSDEC and NYSDOH, including activities to be conducted during the Preliminary Design Investigation (PDI).  The PDI activities are conducted to provide additional design related data. PDI activities were initiated in December and consist of utility preclearance, geophysical and land surveys, drilling, test pit excavation, groundwater sample collection throughout the OU-2 properties.

Ongoing activities:

  •  Land survey of the property and offsite areas.

Future (two week look-ahead) activities:

  • Conduct soil drilling activities on the offsite areas.
  • Conduct groundwater sampling activities as a part of the PDI field activities.
  • Complete land survey of the property and offsite areas.
  • Conduct fence repair work.

Recently Completed Activities:

  • Completed geotechnical soil drilling and test pit excavation activities as part of  PDI field activities.

Community Air Monitoring Plan Summary

Operable Unit 1 (40 Willow Avenue)

A Community Air Monitoring Plan (CAMP) is implemented when intrusive activities are performed at Operable Unit 1.  However, there were no intrusive activities at OU-1 during the month of January that required CAMP monitoring. Copies of previous weekly CAMP reports and other site documents for OU-1 are stored at the two public document repositories for the project. 

Operable Unit 2 (25 Willow Avenue)

A Community Air Monitoring Plan (CAMP) is implemented in support of the PDI activities at the OU-2 properties during intrusive work .  The CAMP consists of portable monitors placed upwind and downwind of the work area.  Concentrations of vapors and dust associated with the pre-design investigation drilling and waste handling were below levels requiring action in the NYSDEC and NYSDOH approved plan.

Community Board 1
One Edgewater Plaza
Room 311
Staten Island, NY 10305
Phone #: (718) 981-6900
Borough President’s Office
Borough Hall
Staten Island, New York 10301
Phone #: (718) 816-2057

If you have any questions or comments about the work on the site, please use the site's Telephone Hotline at 718-982-7349.