Site Name: SOMERSWORTH SANITARY LANDFILL
EPA ID: NHD980520225 EPA Region: 01 Metro Statistical Area: 6450
BLACKWATER RD, SOMERSWORTH, NH 03878
Site Description:
MUNIC LF W/GARAGE FACILITY COVERING 24 ACRES. CONVERTED FR BURNING DUMP F/RESIDL, COMMRCL & INDUSTL WASTES TO SANITARY LF IN 1950. SURF WTR & GRND WTR CONTAM W/CARBON TET, ETHLYBENZENE, TOLUENE& METALS. LEACHATE BRKOUTS NOTED.CLAY DOME BUIL
Remediation Information (Records of Decision)
Operable Unit: 01
ROD ID: EPA/ROD/R01-94/087 ROD Date: 06/21/94
Contaminant: VOCs
Keys: slurry wall, RCRA, institutional controls, groundwater monitoring, landfill, fencing, contaminants and VOCs.
Abstract:
Please note that the text in this document summarizes the Record of Decision for the purposes of facilitating searching and retrieving key text on the ROD. It is not the officially approved abstract drafted by the EPA Regional offices. Once EPA Headquarters receives the official abstract, this text will be replaced.
The 26-acre Somersworth Sanitary Landfill is an inactive municipal landfill in Somersworth, New Hampshire. Land use in the area is predominantly residential and recreational. In addition, the landfill is entirely within the Peter's Marsh Brook surface drainage basin. This Basin supplies water for both the cities of Somersworth and Berwick, Maine. The landfill was operated by the City and accepted municipal and industrial waste from the mid 1930's until 1981. In 1981, the City ceased disposal operations at the landfill and began taking wastes to a regional landfill. From 1981 to the present, in the southwest portion of the landfill, the wastes which could not be incinerated were stockpiled and hauled away.
With the cessation of landfilling operations, the City installed four groundwater monitoring wells. Samples taken from these wells indicated the presence of VOC. As a result of this and subsequent investigations, the site was placed on the NPL list on September 8, 1983. In 1989, the Somersworth Landfill Trust (SLT) was formed by the City of Somersworth and approximately thirty businesses and industries. On April 28, 1989, the SLT signed an Administrative Order by Consent with EPA and the State of New Hampshire. By this order, the SLT agreed to complete limited aspects of the Remedial Investigation (RI) and to prepare the Feasibility Study (FS) for the site. On December 8, 1993, EPA notified thirty-one parties, many of which were members of the SLT, of their potential liability with respect to the site.
This ROD (OU1) addresses both source control and management of migration alternatives. The remedy provides treatment of contaminated overburden and bedrock groundwater with flushing of contamination from the source area.
The remedy status for the media addressed in this ROD are as follows:
Groundwater 1 is Interim Action. The media volume associated with the Landfill - Municipality Owned site is not documented. Soil 1 is Final Action. The media volume associated with the Landfill - Municipality Owned site is not documented. The state concurs with the selected remedy.
Remedy:
The selected remedial action for source control and groundwater includes an innovative, in-situ chemical treatment wall with groundwater diversion and a permeable landfill cover. After specified groundwater clean-up levels are achieved, an appropriate landfill cover will be constructed. If the preferred alternative will not meet performance standards, then a contingency remedy will be implemented. This contingency remedy will be constructed in two stages. Stage One includes installation of a perimeter slurry wall, a diversion trench on the upgradient side of the landfill, and a multi-layer landfill cover that complies with RCRA C requirements. Stage Two involves extraction and treatment of overburden groundwater from within the slurry wall with on-site treatment and disposal or pretreatment and discharge to a wastewater treatment facility. The preferred alternative and the contingency measures will all include a bedrock groundwater extraction system, natural attenuation for the wetlands groundwater plume, a groundwater monitoring program, and a fence around the landfill. Institutional controls such as deed restrictions or zoning ordinances to ensure that groundwater will not be used may also be implemented.