Protecting Water Quality for Two Communities & the Merrimack River Watershed
Construction is underway on major improvements to the Allenstown Wastewater Treatment Facility, marking an important milestone in a project designed to strengthen treatment reliability for Allenstown and Pembroke while helping protect the water quality of the Suncook and Merrimack Rivers. For years, the Allenstown Sewer Commission has been evaluating ways to address aging infrastructure and improve treatment performance. Following a comprehensive planning and alternatives analysis process, the community is now seeing those efforts take shape as construction begins on a series of critical facility upgrades.

construction on a wastewater treatment facility plant Bringing a Long-Term Vision to Life
At the heart of the project are two new secondary clarifiers that will enhance the facility’s treatment capabilities and provide greater operational flexibility for years to come. Supporting improvements throughout the site will help ensure the facility continues to operate efficiently and reliably while serving both communities.
Key project components include:

  • Two new secondary clarifiers
  • Relocation of the plant water system
  • New sludge pumps and associated piping
  • New gravity sewers to convey clarifier effluent to the disinfection process
  • Supporting site improvements and utility modifications

Transforming these recommended improvements into a buildable project required careful coordination and design. The project team worked through complex site constraints to identify suitable locations for the new clarifiers while maintaining plant operations, accommodating existing infrastructure, relocating utilities, obtaining environmental permits, and coordinating closely with facility staff throughout the design process.

Construction Moves the Project into its Most Visible Phase
crane operating at a construction site at a wastewater treatment facility plant With construction now underway, years of planning, design, permitting, and funding coordination are becoming visible progress on site. New infrastructure is beginning to take shape, representing a significant investment in the long-term reliability and resilience of the wastewater system. While wastewater facilities often operate behind the scenes, they provide essential services that communities rely on every day. These improvements will help position the facility to meet future demands while continuing to protect local waterways and support environmental stewardship throughout the watershed.

Supporting the Project from Concept Through Construction
Hoyle Tanner provided planning, alternatives analysis, conceptual and final design, permitting assistance, funding support, and public outreach throughout the project. The team also worked with the Allenstown Sewer Commission to secure funding and build community support through public presentations and outreach efforts. As construction continues, Hoyle Tanner remains actively involved, working alongside the Allenstown Sewer Commission and project partners to help deliver these critical improvements and bring years of planning from concept to reality.