SANBORN Hl; HEAD 20 Foundry Street
Building Trust. Engineering Success. Concord, NH 03301
Mr. Kerry Converse September 2, 2016
Landfill Engineer
Nashua Division of Public Works, Solid Waste Department
840 West Hollis Street
Nashua, NH 03062
Re: | Proposed Engineering Scope of Services
Type II Permit Modification Application and Construction Documents
Phase III Landfill Expansion, Four Hills Landfill, Nashua, New Hampshire
Dear Kerry:
Sanborn, Head & Associates, Inc. (Sanborn Head) is pleased to present our proposed
engineering scope of services to prepare a Type II Modification to Solid Waste Facility
Permit (Type II PMA) and construction documents for Phase III at the Four Hills Landfill.
Phase III is the third and final permitted expansion area associated with the lined landfill
approved by the New Hampshire Department of Environmental Services (NHDES) as
Standard Permit Number DES-SW-SP-002 issued on June 26, 1995, and modified on
February 27, 1998. Based on a review of available permitting documents, we understand
that the proposed Phase III expansion would consist of about 9.4 acres of lined area and
would provide about 1.0 million cubic yards (yd3) of airspace. Furthermore, we
understand that a portion of the 9.4-acre lined landfill expansion is located within the 500-
foot residential setback, and, as such, that portion of the expansion area would not be
eligible for waste placement and the projected airspace may be less than previously
calculated.
BACKGROUND
We understand the Phase | of the lined landfill began accepting waste in 2003 and that
Phase II began accepting waste in 2009. Construction permitting for each phase of the
lined landfill involved preparing a Type II PMA and an Alteration of Terrain (AoT) permit
application for NHDES review and approval. We anticipate that similar permit applications
will be required for Phase IIL.
According to the available permit documents, the design of the Phase III leachate collection
and transmission system is different than that constructed for the previous phases. While
Phases I and II incorporated a gravity leachate drain that includes a penetration through
the liner system at the north end of Phase I, the proposed liner base grading in Phase III
does not lead itself to continuing the gravity drain concept. Rather, a leachate collection
sump and pump system will be needed to remove leachate from the Phase III lined area.
We understand that the collected leachate will be pumped north to the leachate manhole
associated with Phase I, from which the leachate would drain by gravity to the City’s
wastewater treatment plant. Because a leachate pump system will be needed for the Phase
III expansion, Sanborn Head proposes to incorporate a supervisory control and data
SANBORN, HEAD & ASSOCIATES, INC. www.sanbornhead.com
