The Greater Lawrence Sanitary District (GLSD) needed to upgrade a 135 MGD pump station and replace an existing 72-inch prestressed concrete cylinder pipe (PCCP) pipeline which was 35 years old and had experienced several reinforcing wire failures. Kleinfelder performed an alternatives analysis during design to address significant project challenges. The project required environmental permitting as well as permits from an active railroad operator and acquisition of easements along the project path.

Implementing Improvements Without Service Disruption

Significant challenges included constructing the 72-inch pipeline up to 25 feet deep in close proximity to and below the active existing 72-inch force main. The team also designed a new steel pump discharge header (up to 72 inch) inside the pumping station while the existing exterior header remained in service. Other improvements included replacement of four 42-inch knife valves that were not functional and upgrades to two 38,000 gallons per minute pumps. The project required large diameter below grade wall penetrations during construction. Other critical construction elements included two separate pipe jackings (including one under the railroad), sequencing and scheduling, thrust support, and connection to the influent structure at the wastewater treatment plant.

Planning, Design, and Construction Phase Services

Kleinfelder completed the planning, design, and construction phase services of this $13 million project which included replacement of 2,500 feet of 72- inch PCCP force main with a new fiberglass reinforced plastic (FRP) force main and related improvements to a 135 MGD pumping station.

Project Results

The plan recognized that protecting and keeping the existing pump station and force main operational during construction and minimizing construction impacts to the residential neighborhood were a client priority. Kleinfelder also assisted GLSD with acquiring State Revolving Fund (SRF) low interest loans for the full cost of the project.

Project Details

Location:
North Andover, MA

Owner:
Greater Lawrence Sanitary District (GLSD)